Line data Source code
1 : // SPDX-License-Identifier: GPL-2.0
2 : /*
3 : * Performance events core code:
4 : *
5 : * Copyright (C) 2008 Thomas Gleixner <tglx@linutronix.de>
6 : * Copyright (C) 2008-2011 Red Hat, Inc., Ingo Molnar
7 : * Copyright (C) 2008-2011 Red Hat, Inc., Peter Zijlstra
8 : * Copyright © 2009 Paul Mackerras, IBM Corp. <paulus@au1.ibm.com>
9 : */
10 :
11 : #include <linux/fs.h>
12 : #include <linux/mm.h>
13 : #include <linux/cpu.h>
14 : #include <linux/smp.h>
15 : #include <linux/idr.h>
16 : #include <linux/file.h>
17 : #include <linux/poll.h>
18 : #include <linux/slab.h>
19 : #include <linux/hash.h>
20 : #include <linux/tick.h>
21 : #include <linux/sysfs.h>
22 : #include <linux/dcache.h>
23 : #include <linux/percpu.h>
24 : #include <linux/ptrace.h>
25 : #include <linux/reboot.h>
26 : #include <linux/vmstat.h>
27 : #include <linux/device.h>
28 : #include <linux/export.h>
29 : #include <linux/vmalloc.h>
30 : #include <linux/hardirq.h>
31 : #include <linux/hugetlb.h>
32 : #include <linux/rculist.h>
33 : #include <linux/uaccess.h>
34 : #include <linux/syscalls.h>
35 : #include <linux/anon_inodes.h>
36 : #include <linux/kernel_stat.h>
37 : #include <linux/cgroup.h>
38 : #include <linux/perf_event.h>
39 : #include <linux/trace_events.h>
40 : #include <linux/hw_breakpoint.h>
41 : #include <linux/mm_types.h>
42 : #include <linux/module.h>
43 : #include <linux/mman.h>
44 : #include <linux/compat.h>
45 : #include <linux/bpf.h>
46 : #include <linux/filter.h>
47 : #include <linux/namei.h>
48 : #include <linux/parser.h>
49 : #include <linux/sched/clock.h>
50 : #include <linux/sched/mm.h>
51 : #include <linux/proc_ns.h>
52 : #include <linux/mount.h>
53 : #include <linux/min_heap.h>
54 : #include <linux/highmem.h>
55 : #include <linux/pgtable.h>
56 : #include <linux/buildid.h>
57 :
58 : #include "internal.h"
59 :
60 : #include <asm/irq_regs.h>
61 :
62 : typedef int (*remote_function_f)(void *);
63 :
64 : struct remote_function_call {
65 : struct task_struct *p;
66 : remote_function_f func;
67 : void *info;
68 : int ret;
69 : };
70 :
71 0 : static void remote_function(void *data)
72 : {
73 0 : struct remote_function_call *tfc = data;
74 0 : struct task_struct *p = tfc->p;
75 :
76 0 : if (p) {
77 : /* -EAGAIN */
78 0 : if (task_cpu(p) != smp_processor_id())
79 : return;
80 :
81 : /*
82 : * Now that we're on right CPU with IRQs disabled, we can test
83 : * if we hit the right task without races.
84 : */
85 :
86 0 : tfc->ret = -ESRCH; /* No such (running) process */
87 0 : if (p != current)
88 : return;
89 : }
90 :
91 0 : tfc->ret = tfc->func(tfc->info);
92 : }
93 :
94 : /**
95 : * task_function_call - call a function on the cpu on which a task runs
96 : * @p: the task to evaluate
97 : * @func: the function to be called
98 : * @info: the function call argument
99 : *
100 : * Calls the function @func when the task is currently running. This might
101 : * be on the current CPU, which just calls the function directly. This will
102 : * retry due to any failures in smp_call_function_single(), such as if the
103 : * task_cpu() goes offline concurrently.
104 : *
105 : * returns @func return value or -ESRCH or -ENXIO when the process isn't running
106 : */
107 : static int
108 0 : task_function_call(struct task_struct *p, remote_function_f func, void *info)
109 : {
110 0 : struct remote_function_call data = {
111 : .p = p,
112 : .func = func,
113 : .info = info,
114 : .ret = -EAGAIN,
115 : };
116 0 : int ret;
117 :
118 0 : for (;;) {
119 0 : ret = smp_call_function_single(task_cpu(p), remote_function,
120 : &data, 1);
121 0 : if (!ret)
122 0 : ret = data.ret;
123 :
124 0 : if (ret != -EAGAIN)
125 : break;
126 :
127 0 : cond_resched();
128 : }
129 :
130 0 : return ret;
131 : }
132 :
133 : /**
134 : * cpu_function_call - call a function on the cpu
135 : * @func: the function to be called
136 : * @info: the function call argument
137 : *
138 : * Calls the function @func on the remote cpu.
139 : *
140 : * returns: @func return value or -ENXIO when the cpu is offline
141 : */
142 0 : static int cpu_function_call(int cpu, remote_function_f func, void *info)
143 : {
144 0 : struct remote_function_call data = {
145 : .p = NULL,
146 : .func = func,
147 : .info = info,
148 : .ret = -ENXIO, /* No such CPU */
149 : };
150 :
151 0 : smp_call_function_single(cpu, remote_function, &data, 1);
152 :
153 0 : return data.ret;
154 : }
155 :
156 : static inline struct perf_cpu_context *
157 0 : __get_cpu_context(struct perf_event_context *ctx)
158 : {
159 0 : return this_cpu_ptr(ctx->pmu->pmu_cpu_context);
160 : }
161 :
162 0 : static void perf_ctx_lock(struct perf_cpu_context *cpuctx,
163 : struct perf_event_context *ctx)
164 : {
165 0 : raw_spin_lock(&cpuctx->ctx.lock);
166 0 : if (ctx)
167 0 : raw_spin_lock(&ctx->lock);
168 0 : }
169 :
170 0 : static void perf_ctx_unlock(struct perf_cpu_context *cpuctx,
171 : struct perf_event_context *ctx)
172 : {
173 0 : if (ctx)
174 0 : raw_spin_unlock(&ctx->lock);
175 0 : raw_spin_unlock(&cpuctx->ctx.lock);
176 0 : }
177 :
178 : #define TASK_TOMBSTONE ((void *)-1L)
179 :
180 0 : static bool is_kernel_event(struct perf_event *event)
181 : {
182 0 : return READ_ONCE(event->owner) == TASK_TOMBSTONE;
183 : }
184 :
185 : /*
186 : * On task ctx scheduling...
187 : *
188 : * When !ctx->nr_events a task context will not be scheduled. This means
189 : * we can disable the scheduler hooks (for performance) without leaving
190 : * pending task ctx state.
191 : *
192 : * This however results in two special cases:
193 : *
194 : * - removing the last event from a task ctx; this is relatively straight
195 : * forward and is done in __perf_remove_from_context.
196 : *
197 : * - adding the first event to a task ctx; this is tricky because we cannot
198 : * rely on ctx->is_active and therefore cannot use event_function_call().
199 : * See perf_install_in_context().
200 : *
201 : * If ctx->nr_events, then ctx->is_active and cpuctx->task_ctx are set.
202 : */
203 :
204 : typedef void (*event_f)(struct perf_event *, struct perf_cpu_context *,
205 : struct perf_event_context *, void *);
206 :
207 : struct event_function_struct {
208 : struct perf_event *event;
209 : event_f func;
210 : void *data;
211 : };
212 :
213 0 : static int event_function(void *info)
214 : {
215 0 : struct event_function_struct *efs = info;
216 0 : struct perf_event *event = efs->event;
217 0 : struct perf_event_context *ctx = event->ctx;
218 0 : struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
219 0 : struct perf_event_context *task_ctx = cpuctx->task_ctx;
220 0 : int ret = 0;
221 :
222 0 : lockdep_assert_irqs_disabled();
223 :
224 0 : perf_ctx_lock(cpuctx, task_ctx);
225 : /*
226 : * Since we do the IPI call without holding ctx->lock things can have
227 : * changed, double check we hit the task we set out to hit.
228 : */
229 0 : if (ctx->task) {
230 0 : if (ctx->task != current) {
231 0 : ret = -ESRCH;
232 0 : goto unlock;
233 : }
234 :
235 : /*
236 : * We only use event_function_call() on established contexts,
237 : * and event_function() is only ever called when active (or
238 : * rather, we'll have bailed in task_function_call() or the
239 : * above ctx->task != current test), therefore we must have
240 : * ctx->is_active here.
241 : */
242 0 : WARN_ON_ONCE(!ctx->is_active);
243 : /*
244 : * And since we have ctx->is_active, cpuctx->task_ctx must
245 : * match.
246 : */
247 0 : WARN_ON_ONCE(task_ctx != ctx);
248 : } else {
249 0 : WARN_ON_ONCE(&cpuctx->ctx != ctx);
250 : }
251 :
252 0 : efs->func(event, cpuctx, ctx, efs->data);
253 0 : unlock:
254 0 : perf_ctx_unlock(cpuctx, task_ctx);
255 :
256 0 : return ret;
257 : }
258 :
259 0 : static void event_function_call(struct perf_event *event, event_f func, void *data)
260 : {
261 0 : struct perf_event_context *ctx = event->ctx;
262 0 : struct task_struct *task = READ_ONCE(ctx->task); /* verified in event_function */
263 0 : struct event_function_struct efs = {
264 : .event = event,
265 : .func = func,
266 : .data = data,
267 : };
268 :
269 0 : if (!event->parent) {
270 : /*
271 : * If this is a !child event, we must hold ctx::mutex to
272 : * stabilize the event->ctx relation. See
273 : * perf_event_ctx_lock().
274 : */
275 0 : lockdep_assert_held(&ctx->mutex);
276 : }
277 :
278 0 : if (!task) {
279 0 : cpu_function_call(event->cpu, event_function, &efs);
280 0 : return;
281 : }
282 :
283 0 : if (task == TASK_TOMBSTONE)
284 : return;
285 :
286 0 : again:
287 0 : if (!task_function_call(task, event_function, &efs))
288 : return;
289 :
290 0 : raw_spin_lock_irq(&ctx->lock);
291 : /*
292 : * Reload the task pointer, it might have been changed by
293 : * a concurrent perf_event_context_sched_out().
294 : */
295 0 : task = ctx->task;
296 0 : if (task == TASK_TOMBSTONE) {
297 0 : raw_spin_unlock_irq(&ctx->lock);
298 0 : return;
299 : }
300 0 : if (ctx->is_active) {
301 0 : raw_spin_unlock_irq(&ctx->lock);
302 0 : goto again;
303 : }
304 0 : func(event, NULL, ctx, data);
305 0 : raw_spin_unlock_irq(&ctx->lock);
306 : }
307 :
308 : /*
309 : * Similar to event_function_call() + event_function(), but hard assumes IRQs
310 : * are already disabled and we're on the right CPU.
311 : */
312 0 : static void event_function_local(struct perf_event *event, event_f func, void *data)
313 : {
314 0 : struct perf_event_context *ctx = event->ctx;
315 0 : struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
316 0 : struct task_struct *task = READ_ONCE(ctx->task);
317 0 : struct perf_event_context *task_ctx = NULL;
318 :
319 0 : lockdep_assert_irqs_disabled();
320 :
321 0 : if (task) {
322 0 : if (task == TASK_TOMBSTONE)
323 : return;
324 :
325 : task_ctx = ctx;
326 : }
327 :
328 0 : perf_ctx_lock(cpuctx, task_ctx);
329 :
330 0 : task = ctx->task;
331 0 : if (task == TASK_TOMBSTONE)
332 0 : goto unlock;
333 :
334 0 : if (task) {
335 : /*
336 : * We must be either inactive or active and the right task,
337 : * otherwise we're screwed, since we cannot IPI to somewhere
338 : * else.
339 : */
340 0 : if (ctx->is_active) {
341 0 : if (WARN_ON_ONCE(task != current))
342 0 : goto unlock;
343 :
344 0 : if (WARN_ON_ONCE(cpuctx->task_ctx != ctx))
345 0 : goto unlock;
346 : }
347 : } else {
348 0 : WARN_ON_ONCE(&cpuctx->ctx != ctx);
349 : }
350 :
351 0 : func(event, cpuctx, ctx, data);
352 0 : unlock:
353 0 : perf_ctx_unlock(cpuctx, task_ctx);
354 : }
355 :
356 : #define PERF_FLAG_ALL (PERF_FLAG_FD_NO_GROUP |\
357 : PERF_FLAG_FD_OUTPUT |\
358 : PERF_FLAG_PID_CGROUP |\
359 : PERF_FLAG_FD_CLOEXEC)
360 :
361 : /*
362 : * branch priv levels that need permission checks
363 : */
364 : #define PERF_SAMPLE_BRANCH_PERM_PLM \
365 : (PERF_SAMPLE_BRANCH_KERNEL |\
366 : PERF_SAMPLE_BRANCH_HV)
367 :
368 : enum event_type_t {
369 : EVENT_FLEXIBLE = 0x1,
370 : EVENT_PINNED = 0x2,
371 : EVENT_TIME = 0x4,
372 : /* see ctx_resched() for details */
373 : EVENT_CPU = 0x8,
374 : EVENT_ALL = EVENT_FLEXIBLE | EVENT_PINNED,
375 : };
376 :
377 : /*
378 : * perf_sched_events : >0 events exist
379 : * perf_cgroup_events: >0 per-cpu cgroup events exist on this cpu
380 : */
381 :
382 : static void perf_sched_delayed(struct work_struct *work);
383 : DEFINE_STATIC_KEY_FALSE(perf_sched_events);
384 : static DECLARE_DELAYED_WORK(perf_sched_work, perf_sched_delayed);
385 : static DEFINE_MUTEX(perf_sched_mutex);
386 : static atomic_t perf_sched_count;
387 :
388 : static DEFINE_PER_CPU(atomic_t, perf_cgroup_events);
389 : static DEFINE_PER_CPU(int, perf_sched_cb_usages);
390 : static DEFINE_PER_CPU(struct pmu_event_list, pmu_sb_events);
391 :
392 : static atomic_t nr_mmap_events __read_mostly;
393 : static atomic_t nr_comm_events __read_mostly;
394 : static atomic_t nr_namespaces_events __read_mostly;
395 : static atomic_t nr_task_events __read_mostly;
396 : static atomic_t nr_freq_events __read_mostly;
397 : static atomic_t nr_switch_events __read_mostly;
398 : static atomic_t nr_ksymbol_events __read_mostly;
399 : static atomic_t nr_bpf_events __read_mostly;
400 : static atomic_t nr_cgroup_events __read_mostly;
401 : static atomic_t nr_text_poke_events __read_mostly;
402 : static atomic_t nr_build_id_events __read_mostly;
403 :
404 : static LIST_HEAD(pmus);
405 : static DEFINE_MUTEX(pmus_lock);
406 : static struct srcu_struct pmus_srcu;
407 : static cpumask_var_t perf_online_mask;
408 :
409 : /*
410 : * perf event paranoia level:
411 : * -1 - not paranoid at all
412 : * 0 - disallow raw tracepoint access for unpriv
413 : * 1 - disallow cpu events for unpriv
414 : * 2 - disallow kernel profiling for unpriv
415 : */
416 : int sysctl_perf_event_paranoid __read_mostly = 2;
417 :
418 : /* Minimum for 512 kiB + 1 user control page */
419 : int sysctl_perf_event_mlock __read_mostly = 512 + (PAGE_SIZE / 1024); /* 'free' kiB per user */
420 :
421 : /*
422 : * max perf event sample rate
423 : */
424 : #define DEFAULT_MAX_SAMPLE_RATE 100000
425 : #define DEFAULT_SAMPLE_PERIOD_NS (NSEC_PER_SEC / DEFAULT_MAX_SAMPLE_RATE)
426 : #define DEFAULT_CPU_TIME_MAX_PERCENT 25
427 :
428 : int sysctl_perf_event_sample_rate __read_mostly = DEFAULT_MAX_SAMPLE_RATE;
429 :
430 : static int max_samples_per_tick __read_mostly = DIV_ROUND_UP(DEFAULT_MAX_SAMPLE_RATE, HZ);
431 : static int perf_sample_period_ns __read_mostly = DEFAULT_SAMPLE_PERIOD_NS;
432 :
433 : static int perf_sample_allowed_ns __read_mostly =
434 : DEFAULT_SAMPLE_PERIOD_NS * DEFAULT_CPU_TIME_MAX_PERCENT / 100;
435 :
436 0 : static void update_perf_cpu_limits(void)
437 : {
438 0 : u64 tmp = perf_sample_period_ns;
439 :
440 0 : tmp *= sysctl_perf_cpu_time_max_percent;
441 0 : tmp = div_u64(tmp, 100);
442 0 : if (!tmp)
443 0 : tmp = 1;
444 :
445 0 : WRITE_ONCE(perf_sample_allowed_ns, tmp);
446 0 : }
447 :
448 : static bool perf_rotate_context(struct perf_cpu_context *cpuctx);
449 :
450 0 : int perf_proc_update_handler(struct ctl_table *table, int write,
451 : void *buffer, size_t *lenp, loff_t *ppos)
452 : {
453 0 : int ret;
454 0 : int perf_cpu = sysctl_perf_cpu_time_max_percent;
455 : /*
456 : * If throttling is disabled don't allow the write:
457 : */
458 0 : if (write && (perf_cpu == 100 || perf_cpu == 0))
459 : return -EINVAL;
460 :
461 0 : ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
462 0 : if (ret || !write)
463 : return ret;
464 :
465 0 : max_samples_per_tick = DIV_ROUND_UP(sysctl_perf_event_sample_rate, HZ);
466 0 : perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
467 0 : update_perf_cpu_limits();
468 :
469 0 : return 0;
470 : }
471 :
472 : int sysctl_perf_cpu_time_max_percent __read_mostly = DEFAULT_CPU_TIME_MAX_PERCENT;
473 :
474 0 : int perf_cpu_time_max_percent_handler(struct ctl_table *table, int write,
475 : void *buffer, size_t *lenp, loff_t *ppos)
476 : {
477 0 : int ret = proc_dointvec_minmax(table, write, buffer, lenp, ppos);
478 :
479 0 : if (ret || !write)
480 : return ret;
481 :
482 0 : if (sysctl_perf_cpu_time_max_percent == 100 ||
483 : sysctl_perf_cpu_time_max_percent == 0) {
484 0 : printk(KERN_WARNING
485 : "perf: Dynamic interrupt throttling disabled, can hang your system!\n");
486 0 : WRITE_ONCE(perf_sample_allowed_ns, 0);
487 : } else {
488 0 : update_perf_cpu_limits();
489 : }
490 :
491 : return 0;
492 : }
493 :
494 : /*
495 : * perf samples are done in some very critical code paths (NMIs).
496 : * If they take too much CPU time, the system can lock up and not
497 : * get any real work done. This will drop the sample rate when
498 : * we detect that events are taking too long.
499 : */
500 : #define NR_ACCUMULATED_SAMPLES 128
501 : static DEFINE_PER_CPU(u64, running_sample_length);
502 :
503 : static u64 __report_avg;
504 : static u64 __report_allowed;
505 :
506 0 : static void perf_duration_warn(struct irq_work *w)
507 : {
508 0 : printk_ratelimited(KERN_INFO
509 : "perf: interrupt took too long (%lld > %lld), lowering "
510 : "kernel.perf_event_max_sample_rate to %d\n",
511 : __report_avg, __report_allowed,
512 : sysctl_perf_event_sample_rate);
513 0 : }
514 :
515 : static DEFINE_IRQ_WORK(perf_duration_work, perf_duration_warn);
516 :
517 0 : void perf_sample_event_took(u64 sample_len_ns)
518 : {
519 0 : u64 max_len = READ_ONCE(perf_sample_allowed_ns);
520 0 : u64 running_len;
521 0 : u64 avg_len;
522 0 : u32 max;
523 :
524 0 : if (max_len == 0)
525 : return;
526 :
527 : /* Decay the counter by 1 average sample. */
528 0 : running_len = __this_cpu_read(running_sample_length);
529 0 : running_len -= running_len/NR_ACCUMULATED_SAMPLES;
530 0 : running_len += sample_len_ns;
531 0 : __this_cpu_write(running_sample_length, running_len);
532 :
533 : /*
534 : * Note: this will be biased artifically low until we have
535 : * seen NR_ACCUMULATED_SAMPLES. Doing it this way keeps us
536 : * from having to maintain a count.
537 : */
538 0 : avg_len = running_len/NR_ACCUMULATED_SAMPLES;
539 0 : if (avg_len <= max_len)
540 : return;
541 :
542 0 : __report_avg = avg_len;
543 0 : __report_allowed = max_len;
544 :
545 : /*
546 : * Compute a throttle threshold 25% below the current duration.
547 : */
548 0 : avg_len += avg_len / 4;
549 0 : max = (TICK_NSEC / 100) * sysctl_perf_cpu_time_max_percent;
550 0 : if (avg_len < max)
551 0 : max /= (u32)avg_len;
552 : else
553 : max = 1;
554 :
555 0 : WRITE_ONCE(perf_sample_allowed_ns, avg_len);
556 0 : WRITE_ONCE(max_samples_per_tick, max);
557 :
558 0 : sysctl_perf_event_sample_rate = max * HZ;
559 0 : perf_sample_period_ns = NSEC_PER_SEC / sysctl_perf_event_sample_rate;
560 :
561 0 : if (!irq_work_queue(&perf_duration_work)) {
562 0 : early_printk("perf: interrupt took too long (%lld > %lld), lowering "
563 : "kernel.perf_event_max_sample_rate to %d\n",
564 : __report_avg, __report_allowed,
565 : sysctl_perf_event_sample_rate);
566 : }
567 : }
568 :
569 : static atomic64_t perf_event_id;
570 :
571 : static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
572 : enum event_type_t event_type);
573 :
574 : static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
575 : enum event_type_t event_type,
576 : struct task_struct *task);
577 :
578 : static void update_context_time(struct perf_event_context *ctx);
579 : static u64 perf_event_time(struct perf_event *event);
580 :
581 0 : void __weak perf_event_print_debug(void) { }
582 :
583 0 : extern __weak const char *perf_pmu_name(void)
584 : {
585 0 : return "pmu";
586 : }
587 :
588 0 : static inline u64 perf_clock(void)
589 : {
590 0 : return local_clock();
591 : }
592 :
593 0 : static inline u64 perf_event_clock(struct perf_event *event)
594 : {
595 0 : return event->clock();
596 : }
597 :
598 : /*
599 : * State based event timekeeping...
600 : *
601 : * The basic idea is to use event->state to determine which (if any) time
602 : * fields to increment with the current delta. This means we only need to
603 : * update timestamps when we change state or when they are explicitly requested
604 : * (read).
605 : *
606 : * Event groups make things a little more complicated, but not terribly so. The
607 : * rules for a group are that if the group leader is OFF the entire group is
608 : * OFF, irrespecive of what the group member states are. This results in
609 : * __perf_effective_state().
610 : *
611 : * A futher ramification is that when a group leader flips between OFF and
612 : * !OFF, we need to update all group member times.
613 : *
614 : *
615 : * NOTE: perf_event_time() is based on the (cgroup) context time, and thus we
616 : * need to make sure the relevant context time is updated before we try and
617 : * update our timestamps.
618 : */
619 :
620 : static __always_inline enum perf_event_state
621 0 : __perf_effective_state(struct perf_event *event)
622 : {
623 0 : struct perf_event *leader = event->group_leader;
624 :
625 0 : if (leader->state <= PERF_EVENT_STATE_OFF)
626 : return leader->state;
627 :
628 0 : return event->state;
629 : }
630 :
631 : static __always_inline void
632 0 : __perf_update_times(struct perf_event *event, u64 now, u64 *enabled, u64 *running)
633 : {
634 0 : enum perf_event_state state = __perf_effective_state(event);
635 0 : u64 delta = now - event->tstamp;
636 :
637 0 : *enabled = event->total_time_enabled;
638 0 : if (state >= PERF_EVENT_STATE_INACTIVE)
639 0 : *enabled += delta;
640 :
641 0 : *running = event->total_time_running;
642 0 : if (state >= PERF_EVENT_STATE_ACTIVE)
643 0 : *running += delta;
644 : }
645 :
646 0 : static void perf_event_update_time(struct perf_event *event)
647 : {
648 0 : u64 now = perf_event_time(event);
649 :
650 0 : __perf_update_times(event, now, &event->total_time_enabled,
651 : &event->total_time_running);
652 0 : event->tstamp = now;
653 0 : }
654 :
655 0 : static void perf_event_update_sibling_time(struct perf_event *leader)
656 : {
657 0 : struct perf_event *sibling;
658 :
659 0 : for_each_sibling_event(sibling, leader)
660 0 : perf_event_update_time(sibling);
661 0 : }
662 :
663 : static void
664 0 : perf_event_set_state(struct perf_event *event, enum perf_event_state state)
665 : {
666 0 : if (event->state == state)
667 : return;
668 :
669 0 : perf_event_update_time(event);
670 : /*
671 : * If a group leader gets enabled/disabled all its siblings
672 : * are affected too.
673 : */
674 0 : if ((event->state < 0) ^ (state < 0))
675 0 : perf_event_update_sibling_time(event);
676 :
677 0 : WRITE_ONCE(event->state, state);
678 : }
679 :
680 : #ifdef CONFIG_CGROUP_PERF
681 :
682 : static inline bool
683 : perf_cgroup_match(struct perf_event *event)
684 : {
685 : struct perf_event_context *ctx = event->ctx;
686 : struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
687 :
688 : /* @event doesn't care about cgroup */
689 : if (!event->cgrp)
690 : return true;
691 :
692 : /* wants specific cgroup scope but @cpuctx isn't associated with any */
693 : if (!cpuctx->cgrp)
694 : return false;
695 :
696 : /*
697 : * Cgroup scoping is recursive. An event enabled for a cgroup is
698 : * also enabled for all its descendant cgroups. If @cpuctx's
699 : * cgroup is a descendant of @event's (the test covers identity
700 : * case), it's a match.
701 : */
702 : return cgroup_is_descendant(cpuctx->cgrp->css.cgroup,
703 : event->cgrp->css.cgroup);
704 : }
705 :
706 : static inline void perf_detach_cgroup(struct perf_event *event)
707 : {
708 : css_put(&event->cgrp->css);
709 : event->cgrp = NULL;
710 : }
711 :
712 : static inline int is_cgroup_event(struct perf_event *event)
713 : {
714 : return event->cgrp != NULL;
715 : }
716 :
717 : static inline u64 perf_cgroup_event_time(struct perf_event *event)
718 : {
719 : struct perf_cgroup_info *t;
720 :
721 : t = per_cpu_ptr(event->cgrp->info, event->cpu);
722 : return t->time;
723 : }
724 :
725 : static inline void __update_cgrp_time(struct perf_cgroup *cgrp)
726 : {
727 : struct perf_cgroup_info *info;
728 : u64 now;
729 :
730 : now = perf_clock();
731 :
732 : info = this_cpu_ptr(cgrp->info);
733 :
734 : info->time += now - info->timestamp;
735 : info->timestamp = now;
736 : }
737 :
738 : static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
739 : {
740 : struct perf_cgroup *cgrp = cpuctx->cgrp;
741 : struct cgroup_subsys_state *css;
742 :
743 : if (cgrp) {
744 : for (css = &cgrp->css; css; css = css->parent) {
745 : cgrp = container_of(css, struct perf_cgroup, css);
746 : __update_cgrp_time(cgrp);
747 : }
748 : }
749 : }
750 :
751 : static inline void update_cgrp_time_from_event(struct perf_event *event)
752 : {
753 : struct perf_cgroup *cgrp;
754 :
755 : /*
756 : * ensure we access cgroup data only when needed and
757 : * when we know the cgroup is pinned (css_get)
758 : */
759 : if (!is_cgroup_event(event))
760 : return;
761 :
762 : cgrp = perf_cgroup_from_task(current, event->ctx);
763 : /*
764 : * Do not update time when cgroup is not active
765 : */
766 : if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup))
767 : __update_cgrp_time(event->cgrp);
768 : }
769 :
770 : static inline void
771 : perf_cgroup_set_timestamp(struct task_struct *task,
772 : struct perf_event_context *ctx)
773 : {
774 : struct perf_cgroup *cgrp;
775 : struct perf_cgroup_info *info;
776 : struct cgroup_subsys_state *css;
777 :
778 : /*
779 : * ctx->lock held by caller
780 : * ensure we do not access cgroup data
781 : * unless we have the cgroup pinned (css_get)
782 : */
783 : if (!task || !ctx->nr_cgroups)
784 : return;
785 :
786 : cgrp = perf_cgroup_from_task(task, ctx);
787 :
788 : for (css = &cgrp->css; css; css = css->parent) {
789 : cgrp = container_of(css, struct perf_cgroup, css);
790 : info = this_cpu_ptr(cgrp->info);
791 : info->timestamp = ctx->timestamp;
792 : }
793 : }
794 :
795 : static DEFINE_PER_CPU(struct list_head, cgrp_cpuctx_list);
796 :
797 : #define PERF_CGROUP_SWOUT 0x1 /* cgroup switch out every event */
798 : #define PERF_CGROUP_SWIN 0x2 /* cgroup switch in events based on task */
799 :
800 : /*
801 : * reschedule events based on the cgroup constraint of task.
802 : *
803 : * mode SWOUT : schedule out everything
804 : * mode SWIN : schedule in based on cgroup for next
805 : */
806 : static void perf_cgroup_switch(struct task_struct *task, int mode)
807 : {
808 : struct perf_cpu_context *cpuctx;
809 : struct list_head *list;
810 : unsigned long flags;
811 :
812 : /*
813 : * Disable interrupts and preemption to avoid this CPU's
814 : * cgrp_cpuctx_entry to change under us.
815 : */
816 : local_irq_save(flags);
817 :
818 : list = this_cpu_ptr(&cgrp_cpuctx_list);
819 : list_for_each_entry(cpuctx, list, cgrp_cpuctx_entry) {
820 : WARN_ON_ONCE(cpuctx->ctx.nr_cgroups == 0);
821 :
822 : perf_ctx_lock(cpuctx, cpuctx->task_ctx);
823 : perf_pmu_disable(cpuctx->ctx.pmu);
824 :
825 : if (mode & PERF_CGROUP_SWOUT) {
826 : cpu_ctx_sched_out(cpuctx, EVENT_ALL);
827 : /*
828 : * must not be done before ctxswout due
829 : * to event_filter_match() in event_sched_out()
830 : */
831 : cpuctx->cgrp = NULL;
832 : }
833 :
834 : if (mode & PERF_CGROUP_SWIN) {
835 : WARN_ON_ONCE(cpuctx->cgrp);
836 : /*
837 : * set cgrp before ctxsw in to allow
838 : * event_filter_match() to not have to pass
839 : * task around
840 : * we pass the cpuctx->ctx to perf_cgroup_from_task()
841 : * because cgorup events are only per-cpu
842 : */
843 : cpuctx->cgrp = perf_cgroup_from_task(task,
844 : &cpuctx->ctx);
845 : cpu_ctx_sched_in(cpuctx, EVENT_ALL, task);
846 : }
847 : perf_pmu_enable(cpuctx->ctx.pmu);
848 : perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
849 : }
850 :
851 : local_irq_restore(flags);
852 : }
853 :
854 : static inline void perf_cgroup_sched_out(struct task_struct *task,
855 : struct task_struct *next)
856 : {
857 : struct perf_cgroup *cgrp1;
858 : struct perf_cgroup *cgrp2 = NULL;
859 :
860 : rcu_read_lock();
861 : /*
862 : * we come here when we know perf_cgroup_events > 0
863 : * we do not need to pass the ctx here because we know
864 : * we are holding the rcu lock
865 : */
866 : cgrp1 = perf_cgroup_from_task(task, NULL);
867 : cgrp2 = perf_cgroup_from_task(next, NULL);
868 :
869 : /*
870 : * only schedule out current cgroup events if we know
871 : * that we are switching to a different cgroup. Otherwise,
872 : * do no touch the cgroup events.
873 : */
874 : if (cgrp1 != cgrp2)
875 : perf_cgroup_switch(task, PERF_CGROUP_SWOUT);
876 :
877 : rcu_read_unlock();
878 : }
879 :
880 : static inline void perf_cgroup_sched_in(struct task_struct *prev,
881 : struct task_struct *task)
882 : {
883 : struct perf_cgroup *cgrp1;
884 : struct perf_cgroup *cgrp2 = NULL;
885 :
886 : rcu_read_lock();
887 : /*
888 : * we come here when we know perf_cgroup_events > 0
889 : * we do not need to pass the ctx here because we know
890 : * we are holding the rcu lock
891 : */
892 : cgrp1 = perf_cgroup_from_task(task, NULL);
893 : cgrp2 = perf_cgroup_from_task(prev, NULL);
894 :
895 : /*
896 : * only need to schedule in cgroup events if we are changing
897 : * cgroup during ctxsw. Cgroup events were not scheduled
898 : * out of ctxsw out if that was not the case.
899 : */
900 : if (cgrp1 != cgrp2)
901 : perf_cgroup_switch(task, PERF_CGROUP_SWIN);
902 :
903 : rcu_read_unlock();
904 : }
905 :
906 : static int perf_cgroup_ensure_storage(struct perf_event *event,
907 : struct cgroup_subsys_state *css)
908 : {
909 : struct perf_cpu_context *cpuctx;
910 : struct perf_event **storage;
911 : int cpu, heap_size, ret = 0;
912 :
913 : /*
914 : * Allow storage to have sufficent space for an iterator for each
915 : * possibly nested cgroup plus an iterator for events with no cgroup.
916 : */
917 : for (heap_size = 1; css; css = css->parent)
918 : heap_size++;
919 :
920 : for_each_possible_cpu(cpu) {
921 : cpuctx = per_cpu_ptr(event->pmu->pmu_cpu_context, cpu);
922 : if (heap_size <= cpuctx->heap_size)
923 : continue;
924 :
925 : storage = kmalloc_node(heap_size * sizeof(struct perf_event *),
926 : GFP_KERNEL, cpu_to_node(cpu));
927 : if (!storage) {
928 : ret = -ENOMEM;
929 : break;
930 : }
931 :
932 : raw_spin_lock_irq(&cpuctx->ctx.lock);
933 : if (cpuctx->heap_size < heap_size) {
934 : swap(cpuctx->heap, storage);
935 : if (storage == cpuctx->heap_default)
936 : storage = NULL;
937 : cpuctx->heap_size = heap_size;
938 : }
939 : raw_spin_unlock_irq(&cpuctx->ctx.lock);
940 :
941 : kfree(storage);
942 : }
943 :
944 : return ret;
945 : }
946 :
947 : static inline int perf_cgroup_connect(int fd, struct perf_event *event,
948 : struct perf_event_attr *attr,
949 : struct perf_event *group_leader)
950 : {
951 : struct perf_cgroup *cgrp;
952 : struct cgroup_subsys_state *css;
953 : struct fd f = fdget(fd);
954 : int ret = 0;
955 :
956 : if (!f.file)
957 : return -EBADF;
958 :
959 : css = css_tryget_online_from_dir(f.file->f_path.dentry,
960 : &perf_event_cgrp_subsys);
961 : if (IS_ERR(css)) {
962 : ret = PTR_ERR(css);
963 : goto out;
964 : }
965 :
966 : ret = perf_cgroup_ensure_storage(event, css);
967 : if (ret)
968 : goto out;
969 :
970 : cgrp = container_of(css, struct perf_cgroup, css);
971 : event->cgrp = cgrp;
972 :
973 : /*
974 : * all events in a group must monitor
975 : * the same cgroup because a task belongs
976 : * to only one perf cgroup at a time
977 : */
978 : if (group_leader && group_leader->cgrp != cgrp) {
979 : perf_detach_cgroup(event);
980 : ret = -EINVAL;
981 : }
982 : out:
983 : fdput(f);
984 : return ret;
985 : }
986 :
987 : static inline void
988 : perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
989 : {
990 : struct perf_cgroup_info *t;
991 : t = per_cpu_ptr(event->cgrp->info, event->cpu);
992 : event->shadow_ctx_time = now - t->timestamp;
993 : }
994 :
995 : static inline void
996 : perf_cgroup_event_enable(struct perf_event *event, struct perf_event_context *ctx)
997 : {
998 : struct perf_cpu_context *cpuctx;
999 :
1000 : if (!is_cgroup_event(event))
1001 : return;
1002 :
1003 : /*
1004 : * Because cgroup events are always per-cpu events,
1005 : * @ctx == &cpuctx->ctx.
1006 : */
1007 : cpuctx = container_of(ctx, struct perf_cpu_context, ctx);
1008 :
1009 : /*
1010 : * Since setting cpuctx->cgrp is conditional on the current @cgrp
1011 : * matching the event's cgroup, we must do this for every new event,
1012 : * because if the first would mismatch, the second would not try again
1013 : * and we would leave cpuctx->cgrp unset.
1014 : */
1015 : if (ctx->is_active && !cpuctx->cgrp) {
1016 : struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
1017 :
1018 : if (cgroup_is_descendant(cgrp->css.cgroup, event->cgrp->css.cgroup))
1019 : cpuctx->cgrp = cgrp;
1020 : }
1021 :
1022 : if (ctx->nr_cgroups++)
1023 : return;
1024 :
1025 : list_add(&cpuctx->cgrp_cpuctx_entry,
1026 : per_cpu_ptr(&cgrp_cpuctx_list, event->cpu));
1027 : }
1028 :
1029 : static inline void
1030 : perf_cgroup_event_disable(struct perf_event *event, struct perf_event_context *ctx)
1031 : {
1032 : struct perf_cpu_context *cpuctx;
1033 :
1034 : if (!is_cgroup_event(event))
1035 : return;
1036 :
1037 : /*
1038 : * Because cgroup events are always per-cpu events,
1039 : * @ctx == &cpuctx->ctx.
1040 : */
1041 : cpuctx = container_of(ctx, struct perf_cpu_context, ctx);
1042 :
1043 : if (--ctx->nr_cgroups)
1044 : return;
1045 :
1046 : if (ctx->is_active && cpuctx->cgrp)
1047 : cpuctx->cgrp = NULL;
1048 :
1049 : list_del(&cpuctx->cgrp_cpuctx_entry);
1050 : }
1051 :
1052 : #else /* !CONFIG_CGROUP_PERF */
1053 :
1054 : static inline bool
1055 0 : perf_cgroup_match(struct perf_event *event)
1056 : {
1057 0 : return true;
1058 : }
1059 :
1060 : static inline void perf_detach_cgroup(struct perf_event *event)
1061 : {}
1062 :
1063 0 : static inline int is_cgroup_event(struct perf_event *event)
1064 : {
1065 0 : return 0;
1066 : }
1067 :
1068 0 : static inline void update_cgrp_time_from_event(struct perf_event *event)
1069 : {
1070 0 : }
1071 :
1072 0 : static inline void update_cgrp_time_from_cpuctx(struct perf_cpu_context *cpuctx)
1073 : {
1074 0 : }
1075 :
1076 : static inline void perf_cgroup_sched_out(struct task_struct *task,
1077 : struct task_struct *next)
1078 : {
1079 : }
1080 :
1081 : static inline void perf_cgroup_sched_in(struct task_struct *prev,
1082 : struct task_struct *task)
1083 : {
1084 : }
1085 :
1086 0 : static inline int perf_cgroup_connect(pid_t pid, struct perf_event *event,
1087 : struct perf_event_attr *attr,
1088 : struct perf_event *group_leader)
1089 : {
1090 0 : return -EINVAL;
1091 : }
1092 :
1093 : static inline void
1094 0 : perf_cgroup_set_timestamp(struct task_struct *task,
1095 : struct perf_event_context *ctx)
1096 : {
1097 : }
1098 :
1099 : static inline void
1100 : perf_cgroup_switch(struct task_struct *task, struct task_struct *next)
1101 : {
1102 : }
1103 :
1104 : static inline void
1105 : perf_cgroup_set_shadow_time(struct perf_event *event, u64 now)
1106 : {
1107 : }
1108 :
1109 : static inline u64 perf_cgroup_event_time(struct perf_event *event)
1110 : {
1111 : return 0;
1112 : }
1113 :
1114 : static inline void
1115 0 : perf_cgroup_event_enable(struct perf_event *event, struct perf_event_context *ctx)
1116 : {
1117 0 : }
1118 :
1119 : static inline void
1120 0 : perf_cgroup_event_disable(struct perf_event *event, struct perf_event_context *ctx)
1121 : {
1122 0 : }
1123 : #endif
1124 :
1125 : /*
1126 : * set default to be dependent on timer tick just
1127 : * like original code
1128 : */
1129 : #define PERF_CPU_HRTIMER (1000 / HZ)
1130 : /*
1131 : * function must be called with interrupts disabled
1132 : */
1133 0 : static enum hrtimer_restart perf_mux_hrtimer_handler(struct hrtimer *hr)
1134 : {
1135 0 : struct perf_cpu_context *cpuctx;
1136 0 : bool rotations;
1137 :
1138 0 : lockdep_assert_irqs_disabled();
1139 :
1140 0 : cpuctx = container_of(hr, struct perf_cpu_context, hrtimer);
1141 0 : rotations = perf_rotate_context(cpuctx);
1142 :
1143 0 : raw_spin_lock(&cpuctx->hrtimer_lock);
1144 0 : if (rotations)
1145 0 : hrtimer_forward_now(hr, cpuctx->hrtimer_interval);
1146 : else
1147 0 : cpuctx->hrtimer_active = 0;
1148 0 : raw_spin_unlock(&cpuctx->hrtimer_lock);
1149 :
1150 0 : return rotations ? HRTIMER_RESTART : HRTIMER_NORESTART;
1151 : }
1152 :
1153 8 : static void __perf_mux_hrtimer_init(struct perf_cpu_context *cpuctx, int cpu)
1154 : {
1155 8 : struct hrtimer *timer = &cpuctx->hrtimer;
1156 8 : struct pmu *pmu = cpuctx->ctx.pmu;
1157 8 : u64 interval;
1158 :
1159 : /* no multiplexing needed for SW PMU */
1160 8 : if (pmu->task_ctx_nr == perf_sw_context)
1161 : return;
1162 :
1163 : /*
1164 : * check default is sane, if not set then force to
1165 : * default interval (1/tick)
1166 : */
1167 4 : interval = pmu->hrtimer_interval_ms;
1168 4 : if (interval < 1)
1169 1 : interval = pmu->hrtimer_interval_ms = PERF_CPU_HRTIMER;
1170 :
1171 4 : cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * interval);
1172 :
1173 4 : raw_spin_lock_init(&cpuctx->hrtimer_lock);
1174 4 : hrtimer_init(timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS_PINNED_HARD);
1175 4 : timer->function = perf_mux_hrtimer_handler;
1176 : }
1177 :
1178 0 : static int perf_mux_hrtimer_restart(struct perf_cpu_context *cpuctx)
1179 : {
1180 0 : struct hrtimer *timer = &cpuctx->hrtimer;
1181 0 : struct pmu *pmu = cpuctx->ctx.pmu;
1182 0 : unsigned long flags;
1183 :
1184 : /* not for SW PMU */
1185 0 : if (pmu->task_ctx_nr == perf_sw_context)
1186 : return 0;
1187 :
1188 0 : raw_spin_lock_irqsave(&cpuctx->hrtimer_lock, flags);
1189 0 : if (!cpuctx->hrtimer_active) {
1190 0 : cpuctx->hrtimer_active = 1;
1191 0 : hrtimer_forward_now(timer, cpuctx->hrtimer_interval);
1192 0 : hrtimer_start_expires(timer, HRTIMER_MODE_ABS_PINNED_HARD);
1193 : }
1194 0 : raw_spin_unlock_irqrestore(&cpuctx->hrtimer_lock, flags);
1195 :
1196 0 : return 0;
1197 : }
1198 :
1199 0 : void perf_pmu_disable(struct pmu *pmu)
1200 : {
1201 0 : int *count = this_cpu_ptr(pmu->pmu_disable_count);
1202 0 : if (!(*count)++)
1203 0 : pmu->pmu_disable(pmu);
1204 0 : }
1205 :
1206 0 : void perf_pmu_enable(struct pmu *pmu)
1207 : {
1208 0 : int *count = this_cpu_ptr(pmu->pmu_disable_count);
1209 0 : if (!--(*count))
1210 0 : pmu->pmu_enable(pmu);
1211 0 : }
1212 :
1213 : static DEFINE_PER_CPU(struct list_head, active_ctx_list);
1214 :
1215 : /*
1216 : * perf_event_ctx_activate(), perf_event_ctx_deactivate(), and
1217 : * perf_event_task_tick() are fully serialized because they're strictly cpu
1218 : * affine and perf_event_ctx{activate,deactivate} are called with IRQs
1219 : * disabled, while perf_event_task_tick is called from IRQ context.
1220 : */
1221 0 : static void perf_event_ctx_activate(struct perf_event_context *ctx)
1222 : {
1223 0 : struct list_head *head = this_cpu_ptr(&active_ctx_list);
1224 :
1225 0 : lockdep_assert_irqs_disabled();
1226 :
1227 0 : WARN_ON(!list_empty(&ctx->active_ctx_list));
1228 :
1229 0 : list_add(&ctx->active_ctx_list, head);
1230 0 : }
1231 :
1232 0 : static void perf_event_ctx_deactivate(struct perf_event_context *ctx)
1233 : {
1234 0 : lockdep_assert_irqs_disabled();
1235 :
1236 0 : WARN_ON(list_empty(&ctx->active_ctx_list));
1237 :
1238 0 : list_del_init(&ctx->active_ctx_list);
1239 0 : }
1240 :
1241 0 : static void get_ctx(struct perf_event_context *ctx)
1242 : {
1243 0 : refcount_inc(&ctx->refcount);
1244 0 : }
1245 :
1246 0 : static void *alloc_task_ctx_data(struct pmu *pmu)
1247 : {
1248 0 : if (pmu->task_ctx_cache)
1249 0 : return kmem_cache_zalloc(pmu->task_ctx_cache, GFP_KERNEL);
1250 :
1251 : return NULL;
1252 : }
1253 :
1254 0 : static void free_task_ctx_data(struct pmu *pmu, void *task_ctx_data)
1255 : {
1256 0 : if (pmu->task_ctx_cache && task_ctx_data)
1257 0 : kmem_cache_free(pmu->task_ctx_cache, task_ctx_data);
1258 0 : }
1259 :
1260 0 : static void free_ctx(struct rcu_head *head)
1261 : {
1262 0 : struct perf_event_context *ctx;
1263 :
1264 0 : ctx = container_of(head, struct perf_event_context, rcu_head);
1265 0 : free_task_ctx_data(ctx->pmu, ctx->task_ctx_data);
1266 0 : kfree(ctx);
1267 0 : }
1268 :
1269 0 : static void put_ctx(struct perf_event_context *ctx)
1270 : {
1271 0 : if (refcount_dec_and_test(&ctx->refcount)) {
1272 0 : if (ctx->parent_ctx)
1273 0 : put_ctx(ctx->parent_ctx);
1274 0 : if (ctx->task && ctx->task != TASK_TOMBSTONE)
1275 0 : put_task_struct(ctx->task);
1276 0 : call_rcu(&ctx->rcu_head, free_ctx);
1277 : }
1278 0 : }
1279 :
1280 : /*
1281 : * Because of perf_event::ctx migration in sys_perf_event_open::move_group and
1282 : * perf_pmu_migrate_context() we need some magic.
1283 : *
1284 : * Those places that change perf_event::ctx will hold both
1285 : * perf_event_ctx::mutex of the 'old' and 'new' ctx value.
1286 : *
1287 : * Lock ordering is by mutex address. There are two other sites where
1288 : * perf_event_context::mutex nests and those are:
1289 : *
1290 : * - perf_event_exit_task_context() [ child , 0 ]
1291 : * perf_event_exit_event()
1292 : * put_event() [ parent, 1 ]
1293 : *
1294 : * - perf_event_init_context() [ parent, 0 ]
1295 : * inherit_task_group()
1296 : * inherit_group()
1297 : * inherit_event()
1298 : * perf_event_alloc()
1299 : * perf_init_event()
1300 : * perf_try_init_event() [ child , 1 ]
1301 : *
1302 : * While it appears there is an obvious deadlock here -- the parent and child
1303 : * nesting levels are inverted between the two. This is in fact safe because
1304 : * life-time rules separate them. That is an exiting task cannot fork, and a
1305 : * spawning task cannot (yet) exit.
1306 : *
1307 : * But remember that these are parent<->child context relations, and
1308 : * migration does not affect children, therefore these two orderings should not
1309 : * interact.
1310 : *
1311 : * The change in perf_event::ctx does not affect children (as claimed above)
1312 : * because the sys_perf_event_open() case will install a new event and break
1313 : * the ctx parent<->child relation, and perf_pmu_migrate_context() is only
1314 : * concerned with cpuctx and that doesn't have children.
1315 : *
1316 : * The places that change perf_event::ctx will issue:
1317 : *
1318 : * perf_remove_from_context();
1319 : * synchronize_rcu();
1320 : * perf_install_in_context();
1321 : *
1322 : * to affect the change. The remove_from_context() + synchronize_rcu() should
1323 : * quiesce the event, after which we can install it in the new location. This
1324 : * means that only external vectors (perf_fops, prctl) can perturb the event
1325 : * while in transit. Therefore all such accessors should also acquire
1326 : * perf_event_context::mutex to serialize against this.
1327 : *
1328 : * However; because event->ctx can change while we're waiting to acquire
1329 : * ctx->mutex we must be careful and use the below perf_event_ctx_lock()
1330 : * function.
1331 : *
1332 : * Lock order:
1333 : * exec_update_lock
1334 : * task_struct::perf_event_mutex
1335 : * perf_event_context::mutex
1336 : * perf_event::child_mutex;
1337 : * perf_event_context::lock
1338 : * perf_event::mmap_mutex
1339 : * mmap_lock
1340 : * perf_addr_filters_head::lock
1341 : *
1342 : * cpu_hotplug_lock
1343 : * pmus_lock
1344 : * cpuctx->mutex / perf_event_context::mutex
1345 : */
1346 : static struct perf_event_context *
1347 0 : perf_event_ctx_lock_nested(struct perf_event *event, int nesting)
1348 : {
1349 0 : struct perf_event_context *ctx;
1350 :
1351 : again:
1352 0 : rcu_read_lock();
1353 0 : ctx = READ_ONCE(event->ctx);
1354 0 : if (!refcount_inc_not_zero(&ctx->refcount)) {
1355 0 : rcu_read_unlock();
1356 0 : goto again;
1357 : }
1358 0 : rcu_read_unlock();
1359 :
1360 0 : mutex_lock_nested(&ctx->mutex, nesting);
1361 0 : if (event->ctx != ctx) {
1362 0 : mutex_unlock(&ctx->mutex);
1363 0 : put_ctx(ctx);
1364 0 : goto again;
1365 : }
1366 :
1367 0 : return ctx;
1368 : }
1369 :
1370 : static inline struct perf_event_context *
1371 0 : perf_event_ctx_lock(struct perf_event *event)
1372 : {
1373 0 : return perf_event_ctx_lock_nested(event, 0);
1374 : }
1375 :
1376 0 : static void perf_event_ctx_unlock(struct perf_event *event,
1377 : struct perf_event_context *ctx)
1378 : {
1379 0 : mutex_unlock(&ctx->mutex);
1380 0 : put_ctx(ctx);
1381 0 : }
1382 :
1383 : /*
1384 : * This must be done under the ctx->lock, such as to serialize against
1385 : * context_equiv(), therefore we cannot call put_ctx() since that might end up
1386 : * calling scheduler related locks and ctx->lock nests inside those.
1387 : */
1388 : static __must_check struct perf_event_context *
1389 0 : unclone_ctx(struct perf_event_context *ctx)
1390 : {
1391 0 : struct perf_event_context *parent_ctx = ctx->parent_ctx;
1392 :
1393 0 : lockdep_assert_held(&ctx->lock);
1394 :
1395 0 : if (parent_ctx)
1396 0 : ctx->parent_ctx = NULL;
1397 0 : ctx->generation++;
1398 :
1399 0 : return parent_ctx;
1400 : }
1401 :
1402 0 : static u32 perf_event_pid_type(struct perf_event *event, struct task_struct *p,
1403 : enum pid_type type)
1404 : {
1405 0 : u32 nr;
1406 : /*
1407 : * only top level events have the pid namespace they were created in
1408 : */
1409 0 : if (event->parent)
1410 0 : event = event->parent;
1411 :
1412 0 : nr = __task_pid_nr_ns(p, type, event->ns);
1413 : /* avoid -1 if it is idle thread or runs in another ns */
1414 0 : if (!nr && !pid_alive(p))
1415 0 : nr = -1;
1416 0 : return nr;
1417 : }
1418 :
1419 0 : static u32 perf_event_pid(struct perf_event *event, struct task_struct *p)
1420 : {
1421 0 : return perf_event_pid_type(event, p, PIDTYPE_TGID);
1422 : }
1423 :
1424 0 : static u32 perf_event_tid(struct perf_event *event, struct task_struct *p)
1425 : {
1426 0 : return perf_event_pid_type(event, p, PIDTYPE_PID);
1427 : }
1428 :
1429 : /*
1430 : * If we inherit events we want to return the parent event id
1431 : * to userspace.
1432 : */
1433 0 : static u64 primary_event_id(struct perf_event *event)
1434 : {
1435 0 : u64 id = event->id;
1436 :
1437 0 : if (event->parent)
1438 0 : id = event->parent->id;
1439 :
1440 0 : return id;
1441 : }
1442 :
1443 : /*
1444 : * Get the perf_event_context for a task and lock it.
1445 : *
1446 : * This has to cope with the fact that until it is locked,
1447 : * the context could get moved to another task.
1448 : */
1449 : static struct perf_event_context *
1450 2310 : perf_lock_task_context(struct task_struct *task, int ctxn, unsigned long *flags)
1451 : {
1452 2310 : struct perf_event_context *ctx;
1453 :
1454 2310 : retry:
1455 : /*
1456 : * One of the few rules of preemptible RCU is that one cannot do
1457 : * rcu_read_unlock() while holding a scheduler (or nested) lock when
1458 : * part of the read side critical section was irqs-enabled -- see
1459 : * rcu_read_unlock_special().
1460 : *
1461 : * Since ctx->lock nests under rq->lock we must ensure the entire read
1462 : * side critical section has interrupts disabled.
1463 : */
1464 4620 : local_irq_save(*flags);
1465 2310 : rcu_read_lock();
1466 2310 : ctx = rcu_dereference(task->perf_event_ctxp[ctxn]);
1467 2310 : if (ctx) {
1468 : /*
1469 : * If this context is a clone of another, it might
1470 : * get swapped for another underneath us by
1471 : * perf_event_task_sched_out, though the
1472 : * rcu_read_lock() protects us from any context
1473 : * getting freed. Lock the context and check if it
1474 : * got swapped before we could get the lock, and retry
1475 : * if so. If we locked the right context, then it
1476 : * can't get swapped on us any more.
1477 : */
1478 0 : raw_spin_lock(&ctx->lock);
1479 0 : if (ctx != rcu_dereference(task->perf_event_ctxp[ctxn])) {
1480 0 : raw_spin_unlock(&ctx->lock);
1481 0 : rcu_read_unlock();
1482 0 : local_irq_restore(*flags);
1483 0 : goto retry;
1484 : }
1485 :
1486 0 : if (ctx->task == TASK_TOMBSTONE ||
1487 0 : !refcount_inc_not_zero(&ctx->refcount)) {
1488 0 : raw_spin_unlock(&ctx->lock);
1489 0 : ctx = NULL;
1490 : } else {
1491 0 : WARN_ON_ONCE(ctx->task != task);
1492 : }
1493 : }
1494 2310 : rcu_read_unlock();
1495 2310 : if (!ctx)
1496 2310 : local_irq_restore(*flags);
1497 2310 : return ctx;
1498 : }
1499 :
1500 : /*
1501 : * Get the context for a task and increment its pin_count so it
1502 : * can't get swapped to another task. This also increments its
1503 : * reference count so that the context can't get freed.
1504 : */
1505 : static struct perf_event_context *
1506 2310 : perf_pin_task_context(struct task_struct *task, int ctxn)
1507 : {
1508 2310 : struct perf_event_context *ctx;
1509 2310 : unsigned long flags;
1510 :
1511 2310 : ctx = perf_lock_task_context(task, ctxn, &flags);
1512 2310 : if (ctx) {
1513 0 : ++ctx->pin_count;
1514 0 : raw_spin_unlock_irqrestore(&ctx->lock, flags);
1515 : }
1516 2310 : return ctx;
1517 : }
1518 :
1519 0 : static void perf_unpin_context(struct perf_event_context *ctx)
1520 : {
1521 0 : unsigned long flags;
1522 :
1523 0 : raw_spin_lock_irqsave(&ctx->lock, flags);
1524 0 : --ctx->pin_count;
1525 0 : raw_spin_unlock_irqrestore(&ctx->lock, flags);
1526 0 : }
1527 :
1528 : /*
1529 : * Update the record of the current time in a context.
1530 : */
1531 0 : static void update_context_time(struct perf_event_context *ctx)
1532 : {
1533 0 : u64 now = perf_clock();
1534 :
1535 0 : ctx->time += now - ctx->timestamp;
1536 0 : ctx->timestamp = now;
1537 0 : }
1538 :
1539 0 : static u64 perf_event_time(struct perf_event *event)
1540 : {
1541 0 : struct perf_event_context *ctx = event->ctx;
1542 :
1543 0 : if (is_cgroup_event(event))
1544 : return perf_cgroup_event_time(event);
1545 :
1546 0 : return ctx ? ctx->time : 0;
1547 : }
1548 :
1549 0 : static enum event_type_t get_event_type(struct perf_event *event)
1550 : {
1551 0 : struct perf_event_context *ctx = event->ctx;
1552 0 : enum event_type_t event_type;
1553 :
1554 0 : lockdep_assert_held(&ctx->lock);
1555 :
1556 : /*
1557 : * It's 'group type', really, because if our group leader is
1558 : * pinned, so are we.
1559 : */
1560 0 : if (event->group_leader != event)
1561 0 : event = event->group_leader;
1562 :
1563 0 : event_type = event->attr.pinned ? EVENT_PINNED : EVENT_FLEXIBLE;
1564 0 : if (!ctx->task)
1565 0 : event_type |= EVENT_CPU;
1566 :
1567 0 : return event_type;
1568 : }
1569 :
1570 : /*
1571 : * Helper function to initialize event group nodes.
1572 : */
1573 0 : static void init_event_group(struct perf_event *event)
1574 : {
1575 0 : RB_CLEAR_NODE(&event->group_node);
1576 0 : event->group_index = 0;
1577 : }
1578 :
1579 : /*
1580 : * Extract pinned or flexible groups from the context
1581 : * based on event attrs bits.
1582 : */
1583 : static struct perf_event_groups *
1584 0 : get_event_groups(struct perf_event *event, struct perf_event_context *ctx)
1585 : {
1586 0 : if (event->attr.pinned)
1587 0 : return &ctx->pinned_groups;
1588 : else
1589 0 : return &ctx->flexible_groups;
1590 : }
1591 :
1592 : /*
1593 : * Helper function to initializes perf_event_group trees.
1594 : */
1595 8 : static void perf_event_groups_init(struct perf_event_groups *groups)
1596 : {
1597 8 : groups->tree = RB_ROOT;
1598 8 : groups->index = 0;
1599 : }
1600 :
1601 0 : static inline struct cgroup *event_cgroup(const struct perf_event *event)
1602 : {
1603 0 : struct cgroup *cgroup = NULL;
1604 :
1605 : #ifdef CONFIG_CGROUP_PERF
1606 : if (event->cgrp)
1607 : cgroup = event->cgrp->css.cgroup;
1608 : #endif
1609 :
1610 0 : return cgroup;
1611 : }
1612 :
1613 : /*
1614 : * Compare function for event groups;
1615 : *
1616 : * Implements complex key that first sorts by CPU and then by virtual index
1617 : * which provides ordering when rotating groups for the same CPU.
1618 : */
1619 : static __always_inline int
1620 0 : perf_event_groups_cmp(const int left_cpu, const struct cgroup *left_cgroup,
1621 : const u64 left_group_index, const struct perf_event *right)
1622 : {
1623 0 : if (left_cpu < right->cpu)
1624 : return -1;
1625 0 : if (left_cpu > right->cpu)
1626 : return 1;
1627 :
1628 : #ifdef CONFIG_CGROUP_PERF
1629 : {
1630 : const struct cgroup *right_cgroup = event_cgroup(right);
1631 :
1632 : if (left_cgroup != right_cgroup) {
1633 : if (!left_cgroup) {
1634 : /*
1635 : * Left has no cgroup but right does, no
1636 : * cgroups come first.
1637 : */
1638 : return -1;
1639 : }
1640 : if (!right_cgroup) {
1641 : /*
1642 : * Right has no cgroup but left does, no
1643 : * cgroups come first.
1644 : */
1645 : return 1;
1646 : }
1647 : /* Two dissimilar cgroups, order by id. */
1648 : if (cgroup_id(left_cgroup) < cgroup_id(right_cgroup))
1649 : return -1;
1650 :
1651 : return 1;
1652 : }
1653 : }
1654 : #endif
1655 :
1656 0 : if (left_group_index < right->group_index)
1657 : return -1;
1658 0 : if (left_group_index > right->group_index)
1659 0 : return 1;
1660 :
1661 : return 0;
1662 : }
1663 :
1664 : #define __node_2_pe(node) \
1665 : rb_entry((node), struct perf_event, group_node)
1666 :
1667 0 : static inline bool __group_less(struct rb_node *a, const struct rb_node *b)
1668 : {
1669 0 : struct perf_event *e = __node_2_pe(a);
1670 0 : return perf_event_groups_cmp(e->cpu, event_cgroup(e), e->group_index,
1671 0 : __node_2_pe(b)) < 0;
1672 : }
1673 :
1674 : struct __group_key {
1675 : int cpu;
1676 : struct cgroup *cgroup;
1677 : };
1678 :
1679 0 : static inline int __group_cmp(const void *key, const struct rb_node *node)
1680 : {
1681 0 : const struct __group_key *a = key;
1682 0 : const struct perf_event *b = __node_2_pe(node);
1683 :
1684 : /* partial/subtree match: @cpu, @cgroup; ignore: @group_index */
1685 0 : return perf_event_groups_cmp(a->cpu, a->cgroup, b->group_index, b);
1686 : }
1687 :
1688 : /*
1689 : * Insert @event into @groups' tree; using {@event->cpu, ++@groups->index} for
1690 : * key (see perf_event_groups_less). This places it last inside the CPU
1691 : * subtree.
1692 : */
1693 : static void
1694 0 : perf_event_groups_insert(struct perf_event_groups *groups,
1695 : struct perf_event *event)
1696 : {
1697 0 : event->group_index = ++groups->index;
1698 :
1699 0 : rb_add(&event->group_node, &groups->tree, __group_less);
1700 0 : }
1701 :
1702 : /*
1703 : * Helper function to insert event into the pinned or flexible groups.
1704 : */
1705 : static void
1706 0 : add_event_to_groups(struct perf_event *event, struct perf_event_context *ctx)
1707 : {
1708 0 : struct perf_event_groups *groups;
1709 :
1710 0 : groups = get_event_groups(event, ctx);
1711 0 : perf_event_groups_insert(groups, event);
1712 0 : }
1713 :
1714 : /*
1715 : * Delete a group from a tree.
1716 : */
1717 : static void
1718 0 : perf_event_groups_delete(struct perf_event_groups *groups,
1719 : struct perf_event *event)
1720 : {
1721 0 : WARN_ON_ONCE(RB_EMPTY_NODE(&event->group_node) ||
1722 : RB_EMPTY_ROOT(&groups->tree));
1723 :
1724 0 : rb_erase(&event->group_node, &groups->tree);
1725 0 : init_event_group(event);
1726 0 : }
1727 :
1728 : /*
1729 : * Helper function to delete event from its groups.
1730 : */
1731 : static void
1732 0 : del_event_from_groups(struct perf_event *event, struct perf_event_context *ctx)
1733 : {
1734 0 : struct perf_event_groups *groups;
1735 :
1736 0 : groups = get_event_groups(event, ctx);
1737 0 : perf_event_groups_delete(groups, event);
1738 0 : }
1739 :
1740 : /*
1741 : * Get the leftmost event in the cpu/cgroup subtree.
1742 : */
1743 : static struct perf_event *
1744 0 : perf_event_groups_first(struct perf_event_groups *groups, int cpu,
1745 : struct cgroup *cgrp)
1746 : {
1747 0 : struct __group_key key = {
1748 : .cpu = cpu,
1749 : .cgroup = cgrp,
1750 : };
1751 0 : struct rb_node *node;
1752 :
1753 0 : node = rb_find_first(&key, &groups->tree, __group_cmp);
1754 0 : if (node)
1755 0 : return __node_2_pe(node);
1756 :
1757 : return NULL;
1758 : }
1759 :
1760 : /*
1761 : * Like rb_entry_next_safe() for the @cpu subtree.
1762 : */
1763 : static struct perf_event *
1764 0 : perf_event_groups_next(struct perf_event *event)
1765 : {
1766 0 : struct __group_key key = {
1767 0 : .cpu = event->cpu,
1768 0 : .cgroup = event_cgroup(event),
1769 : };
1770 0 : struct rb_node *next;
1771 :
1772 0 : next = rb_next_match(&key, &event->group_node, __group_cmp);
1773 0 : if (next)
1774 0 : return __node_2_pe(next);
1775 :
1776 : return NULL;
1777 : }
1778 :
1779 : /*
1780 : * Iterate through the whole groups tree.
1781 : */
1782 : #define perf_event_groups_for_each(event, groups) \
1783 : for (event = rb_entry_safe(rb_first(&((groups)->tree)), \
1784 : typeof(*event), group_node); event; \
1785 : event = rb_entry_safe(rb_next(&event->group_node), \
1786 : typeof(*event), group_node))
1787 :
1788 : /*
1789 : * Add an event from the lists for its context.
1790 : * Must be called with ctx->mutex and ctx->lock held.
1791 : */
1792 : static void
1793 0 : list_add_event(struct perf_event *event, struct perf_event_context *ctx)
1794 : {
1795 0 : lockdep_assert_held(&ctx->lock);
1796 :
1797 0 : WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
1798 0 : event->attach_state |= PERF_ATTACH_CONTEXT;
1799 :
1800 0 : event->tstamp = perf_event_time(event);
1801 :
1802 : /*
1803 : * If we're a stand alone event or group leader, we go to the context
1804 : * list, group events are kept attached to the group so that
1805 : * perf_group_detach can, at all times, locate all siblings.
1806 : */
1807 0 : if (event->group_leader == event) {
1808 0 : event->group_caps = event->event_caps;
1809 0 : add_event_to_groups(event, ctx);
1810 : }
1811 :
1812 0 : list_add_rcu(&event->event_entry, &ctx->event_list);
1813 0 : ctx->nr_events++;
1814 0 : if (event->attr.inherit_stat)
1815 0 : ctx->nr_stat++;
1816 :
1817 0 : if (event->state > PERF_EVENT_STATE_OFF)
1818 0 : perf_cgroup_event_enable(event, ctx);
1819 :
1820 0 : ctx->generation++;
1821 0 : }
1822 :
1823 : /*
1824 : * Initialize event state based on the perf_event_attr::disabled.
1825 : */
1826 0 : static inline void perf_event__state_init(struct perf_event *event)
1827 : {
1828 0 : event->state = event->attr.disabled ? PERF_EVENT_STATE_OFF :
1829 : PERF_EVENT_STATE_INACTIVE;
1830 : }
1831 :
1832 0 : static void __perf_event_read_size(struct perf_event *event, int nr_siblings)
1833 : {
1834 0 : int entry = sizeof(u64); /* value */
1835 0 : int size = 0;
1836 0 : int nr = 1;
1837 :
1838 0 : if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
1839 0 : size += sizeof(u64);
1840 :
1841 0 : if (event->attr.read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
1842 0 : size += sizeof(u64);
1843 :
1844 0 : if (event->attr.read_format & PERF_FORMAT_ID)
1845 0 : entry += sizeof(u64);
1846 :
1847 0 : if (event->attr.read_format & PERF_FORMAT_GROUP) {
1848 0 : nr += nr_siblings;
1849 0 : size += sizeof(u64);
1850 : }
1851 :
1852 0 : size += entry * nr;
1853 0 : event->read_size = size;
1854 0 : }
1855 :
1856 0 : static void __perf_event_header_size(struct perf_event *event, u64 sample_type)
1857 : {
1858 0 : struct perf_sample_data *data;
1859 0 : u16 size = 0;
1860 :
1861 0 : if (sample_type & PERF_SAMPLE_IP)
1862 0 : size += sizeof(data->ip);
1863 :
1864 0 : if (sample_type & PERF_SAMPLE_ADDR)
1865 0 : size += sizeof(data->addr);
1866 :
1867 0 : if (sample_type & PERF_SAMPLE_PERIOD)
1868 0 : size += sizeof(data->period);
1869 :
1870 0 : if (sample_type & PERF_SAMPLE_WEIGHT_TYPE)
1871 0 : size += sizeof(data->weight.full);
1872 :
1873 0 : if (sample_type & PERF_SAMPLE_READ)
1874 0 : size += event->read_size;
1875 :
1876 0 : if (sample_type & PERF_SAMPLE_DATA_SRC)
1877 0 : size += sizeof(data->data_src.val);
1878 :
1879 0 : if (sample_type & PERF_SAMPLE_TRANSACTION)
1880 0 : size += sizeof(data->txn);
1881 :
1882 0 : if (sample_type & PERF_SAMPLE_PHYS_ADDR)
1883 0 : size += sizeof(data->phys_addr);
1884 :
1885 0 : if (sample_type & PERF_SAMPLE_CGROUP)
1886 0 : size += sizeof(data->cgroup);
1887 :
1888 0 : if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE)
1889 0 : size += sizeof(data->data_page_size);
1890 :
1891 0 : if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE)
1892 0 : size += sizeof(data->code_page_size);
1893 :
1894 0 : event->header_size = size;
1895 0 : }
1896 :
1897 : /*
1898 : * Called at perf_event creation and when events are attached/detached from a
1899 : * group.
1900 : */
1901 0 : static void perf_event__header_size(struct perf_event *event)
1902 : {
1903 0 : __perf_event_read_size(event,
1904 0 : event->group_leader->nr_siblings);
1905 0 : __perf_event_header_size(event, event->attr.sample_type);
1906 0 : }
1907 :
1908 0 : static void perf_event__id_header_size(struct perf_event *event)
1909 : {
1910 0 : struct perf_sample_data *data;
1911 0 : u64 sample_type = event->attr.sample_type;
1912 0 : u16 size = 0;
1913 :
1914 0 : if (sample_type & PERF_SAMPLE_TID)
1915 0 : size += sizeof(data->tid_entry);
1916 :
1917 0 : if (sample_type & PERF_SAMPLE_TIME)
1918 0 : size += sizeof(data->time);
1919 :
1920 0 : if (sample_type & PERF_SAMPLE_IDENTIFIER)
1921 0 : size += sizeof(data->id);
1922 :
1923 0 : if (sample_type & PERF_SAMPLE_ID)
1924 0 : size += sizeof(data->id);
1925 :
1926 0 : if (sample_type & PERF_SAMPLE_STREAM_ID)
1927 0 : size += sizeof(data->stream_id);
1928 :
1929 0 : if (sample_type & PERF_SAMPLE_CPU)
1930 0 : size += sizeof(data->cpu_entry);
1931 :
1932 0 : event->id_header_size = size;
1933 0 : }
1934 :
1935 0 : static bool perf_event_validate_size(struct perf_event *event)
1936 : {
1937 : /*
1938 : * The values computed here will be over-written when we actually
1939 : * attach the event.
1940 : */
1941 0 : __perf_event_read_size(event, event->group_leader->nr_siblings + 1);
1942 0 : __perf_event_header_size(event, event->attr.sample_type & ~PERF_SAMPLE_READ);
1943 0 : perf_event__id_header_size(event);
1944 :
1945 : /*
1946 : * Sum the lot; should not exceed the 64k limit we have on records.
1947 : * Conservative limit to allow for callchains and other variable fields.
1948 : */
1949 0 : if (event->read_size + event->header_size +
1950 0 : event->id_header_size + sizeof(struct perf_event_header) >= 16*1024)
1951 0 : return false;
1952 :
1953 : return true;
1954 : }
1955 :
1956 0 : static void perf_group_attach(struct perf_event *event)
1957 : {
1958 0 : struct perf_event *group_leader = event->group_leader, *pos;
1959 :
1960 0 : lockdep_assert_held(&event->ctx->lock);
1961 :
1962 : /*
1963 : * We can have double attach due to group movement in perf_event_open.
1964 : */
1965 0 : if (event->attach_state & PERF_ATTACH_GROUP)
1966 : return;
1967 :
1968 0 : event->attach_state |= PERF_ATTACH_GROUP;
1969 :
1970 0 : if (group_leader == event)
1971 : return;
1972 :
1973 0 : WARN_ON_ONCE(group_leader->ctx != event->ctx);
1974 :
1975 0 : group_leader->group_caps &= event->event_caps;
1976 :
1977 0 : list_add_tail(&event->sibling_list, &group_leader->sibling_list);
1978 0 : group_leader->nr_siblings++;
1979 :
1980 0 : perf_event__header_size(group_leader);
1981 :
1982 0 : for_each_sibling_event(pos, group_leader)
1983 0 : perf_event__header_size(pos);
1984 : }
1985 :
1986 : /*
1987 : * Remove an event from the lists for its context.
1988 : * Must be called with ctx->mutex and ctx->lock held.
1989 : */
1990 : static void
1991 0 : list_del_event(struct perf_event *event, struct perf_event_context *ctx)
1992 : {
1993 0 : WARN_ON_ONCE(event->ctx != ctx);
1994 0 : lockdep_assert_held(&ctx->lock);
1995 :
1996 : /*
1997 : * We can have double detach due to exit/hot-unplug + close.
1998 : */
1999 0 : if (!(event->attach_state & PERF_ATTACH_CONTEXT))
2000 : return;
2001 :
2002 0 : event->attach_state &= ~PERF_ATTACH_CONTEXT;
2003 :
2004 0 : ctx->nr_events--;
2005 0 : if (event->attr.inherit_stat)
2006 0 : ctx->nr_stat--;
2007 :
2008 0 : list_del_rcu(&event->event_entry);
2009 :
2010 0 : if (event->group_leader == event)
2011 0 : del_event_from_groups(event, ctx);
2012 :
2013 : /*
2014 : * If event was in error state, then keep it
2015 : * that way, otherwise bogus counts will be
2016 : * returned on read(). The only way to get out
2017 : * of error state is by explicit re-enabling
2018 : * of the event
2019 : */
2020 0 : if (event->state > PERF_EVENT_STATE_OFF) {
2021 0 : perf_cgroup_event_disable(event, ctx);
2022 0 : perf_event_set_state(event, PERF_EVENT_STATE_OFF);
2023 : }
2024 :
2025 0 : ctx->generation++;
2026 : }
2027 :
2028 : static int
2029 0 : perf_aux_output_match(struct perf_event *event, struct perf_event *aux_event)
2030 : {
2031 0 : if (!has_aux(aux_event))
2032 : return 0;
2033 :
2034 0 : if (!event->pmu->aux_output_match)
2035 : return 0;
2036 :
2037 0 : return event->pmu->aux_output_match(aux_event);
2038 : }
2039 :
2040 : static void put_event(struct perf_event *event);
2041 : static void event_sched_out(struct perf_event *event,
2042 : struct perf_cpu_context *cpuctx,
2043 : struct perf_event_context *ctx);
2044 :
2045 0 : static void perf_put_aux_event(struct perf_event *event)
2046 : {
2047 0 : struct perf_event_context *ctx = event->ctx;
2048 0 : struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2049 0 : struct perf_event *iter;
2050 :
2051 : /*
2052 : * If event uses aux_event tear down the link
2053 : */
2054 0 : if (event->aux_event) {
2055 0 : iter = event->aux_event;
2056 0 : event->aux_event = NULL;
2057 0 : put_event(iter);
2058 0 : return;
2059 : }
2060 :
2061 : /*
2062 : * If the event is an aux_event, tear down all links to
2063 : * it from other events.
2064 : */
2065 0 : for_each_sibling_event(iter, event->group_leader) {
2066 0 : if (iter->aux_event != event)
2067 0 : continue;
2068 :
2069 0 : iter->aux_event = NULL;
2070 0 : put_event(event);
2071 :
2072 : /*
2073 : * If it's ACTIVE, schedule it out and put it into ERROR
2074 : * state so that we don't try to schedule it again. Note
2075 : * that perf_event_enable() will clear the ERROR status.
2076 : */
2077 0 : event_sched_out(iter, cpuctx, ctx);
2078 0 : perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
2079 : }
2080 : }
2081 :
2082 0 : static bool perf_need_aux_event(struct perf_event *event)
2083 : {
2084 0 : return !!event->attr.aux_output || !!event->attr.aux_sample_size;
2085 : }
2086 :
2087 0 : static int perf_get_aux_event(struct perf_event *event,
2088 : struct perf_event *group_leader)
2089 : {
2090 : /*
2091 : * Our group leader must be an aux event if we want to be
2092 : * an aux_output. This way, the aux event will precede its
2093 : * aux_output events in the group, and therefore will always
2094 : * schedule first.
2095 : */
2096 0 : if (!group_leader)
2097 : return 0;
2098 :
2099 : /*
2100 : * aux_output and aux_sample_size are mutually exclusive.
2101 : */
2102 0 : if (event->attr.aux_output && event->attr.aux_sample_size)
2103 : return 0;
2104 :
2105 0 : if (event->attr.aux_output &&
2106 0 : !perf_aux_output_match(event, group_leader))
2107 : return 0;
2108 :
2109 0 : if (event->attr.aux_sample_size && !group_leader->pmu->snapshot_aux)
2110 : return 0;
2111 :
2112 0 : if (!atomic_long_inc_not_zero(&group_leader->refcount))
2113 : return 0;
2114 :
2115 : /*
2116 : * Link aux_outputs to their aux event; this is undone in
2117 : * perf_group_detach() by perf_put_aux_event(). When the
2118 : * group in torn down, the aux_output events loose their
2119 : * link to the aux_event and can't schedule any more.
2120 : */
2121 0 : event->aux_event = group_leader;
2122 :
2123 0 : return 1;
2124 : }
2125 :
2126 0 : static inline struct list_head *get_event_list(struct perf_event *event)
2127 : {
2128 0 : struct perf_event_context *ctx = event->ctx;
2129 0 : return event->attr.pinned ? &ctx->pinned_active : &ctx->flexible_active;
2130 : }
2131 :
2132 : /*
2133 : * Events that have PERF_EV_CAP_SIBLING require being part of a group and
2134 : * cannot exist on their own, schedule them out and move them into the ERROR
2135 : * state. Also see _perf_event_enable(), it will not be able to recover
2136 : * this ERROR state.
2137 : */
2138 0 : static inline void perf_remove_sibling_event(struct perf_event *event)
2139 : {
2140 0 : struct perf_event_context *ctx = event->ctx;
2141 0 : struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2142 :
2143 0 : event_sched_out(event, cpuctx, ctx);
2144 0 : perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
2145 0 : }
2146 :
2147 0 : static void perf_group_detach(struct perf_event *event)
2148 : {
2149 0 : struct perf_event *leader = event->group_leader;
2150 0 : struct perf_event *sibling, *tmp;
2151 0 : struct perf_event_context *ctx = event->ctx;
2152 :
2153 0 : lockdep_assert_held(&ctx->lock);
2154 :
2155 : /*
2156 : * We can have double detach due to exit/hot-unplug + close.
2157 : */
2158 0 : if (!(event->attach_state & PERF_ATTACH_GROUP))
2159 : return;
2160 :
2161 0 : event->attach_state &= ~PERF_ATTACH_GROUP;
2162 :
2163 0 : perf_put_aux_event(event);
2164 :
2165 : /*
2166 : * If this is a sibling, remove it from its group.
2167 : */
2168 0 : if (leader != event) {
2169 0 : list_del_init(&event->sibling_list);
2170 0 : event->group_leader->nr_siblings--;
2171 0 : goto out;
2172 : }
2173 :
2174 : /*
2175 : * If this was a group event with sibling events then
2176 : * upgrade the siblings to singleton events by adding them
2177 : * to whatever list we are on.
2178 : */
2179 0 : list_for_each_entry_safe(sibling, tmp, &event->sibling_list, sibling_list) {
2180 :
2181 0 : if (sibling->event_caps & PERF_EV_CAP_SIBLING)
2182 0 : perf_remove_sibling_event(sibling);
2183 :
2184 0 : sibling->group_leader = sibling;
2185 0 : list_del_init(&sibling->sibling_list);
2186 :
2187 : /* Inherit group flags from the previous leader */
2188 0 : sibling->group_caps = event->group_caps;
2189 :
2190 0 : if (!RB_EMPTY_NODE(&event->group_node)) {
2191 0 : add_event_to_groups(sibling, event->ctx);
2192 :
2193 0 : if (sibling->state == PERF_EVENT_STATE_ACTIVE)
2194 0 : list_add_tail(&sibling->active_list, get_event_list(sibling));
2195 : }
2196 :
2197 0 : WARN_ON_ONCE(sibling->ctx != event->ctx);
2198 : }
2199 :
2200 0 : out:
2201 0 : for_each_sibling_event(tmp, leader)
2202 0 : perf_event__header_size(tmp);
2203 :
2204 0 : perf_event__header_size(leader);
2205 : }
2206 :
2207 0 : static bool is_orphaned_event(struct perf_event *event)
2208 : {
2209 0 : return event->state == PERF_EVENT_STATE_DEAD;
2210 : }
2211 :
2212 0 : static inline int __pmu_filter_match(struct perf_event *event)
2213 : {
2214 0 : struct pmu *pmu = event->pmu;
2215 0 : return pmu->filter_match ? pmu->filter_match(event) : 1;
2216 : }
2217 :
2218 : /*
2219 : * Check whether we should attempt to schedule an event group based on
2220 : * PMU-specific filtering. An event group can consist of HW and SW events,
2221 : * potentially with a SW leader, so we must check all the filters, to
2222 : * determine whether a group is schedulable:
2223 : */
2224 0 : static inline int pmu_filter_match(struct perf_event *event)
2225 : {
2226 0 : struct perf_event *sibling;
2227 :
2228 0 : if (!__pmu_filter_match(event))
2229 : return 0;
2230 :
2231 0 : for_each_sibling_event(sibling, event) {
2232 0 : if (!__pmu_filter_match(sibling))
2233 : return 0;
2234 : }
2235 :
2236 : return 1;
2237 : }
2238 :
2239 : static inline int
2240 0 : event_filter_match(struct perf_event *event)
2241 : {
2242 0 : return (event->cpu == -1 || event->cpu == smp_processor_id()) &&
2243 0 : perf_cgroup_match(event) && pmu_filter_match(event);
2244 : }
2245 :
2246 : static void
2247 0 : event_sched_out(struct perf_event *event,
2248 : struct perf_cpu_context *cpuctx,
2249 : struct perf_event_context *ctx)
2250 : {
2251 0 : enum perf_event_state state = PERF_EVENT_STATE_INACTIVE;
2252 :
2253 0 : WARN_ON_ONCE(event->ctx != ctx);
2254 0 : lockdep_assert_held(&ctx->lock);
2255 :
2256 0 : if (event->state != PERF_EVENT_STATE_ACTIVE)
2257 : return;
2258 :
2259 : /*
2260 : * Asymmetry; we only schedule events _IN_ through ctx_sched_in(), but
2261 : * we can schedule events _OUT_ individually through things like
2262 : * __perf_remove_from_context().
2263 : */
2264 0 : list_del_init(&event->active_list);
2265 :
2266 0 : perf_pmu_disable(event->pmu);
2267 :
2268 0 : event->pmu->del(event, 0);
2269 0 : event->oncpu = -1;
2270 :
2271 0 : if (READ_ONCE(event->pending_disable) >= 0) {
2272 0 : WRITE_ONCE(event->pending_disable, -1);
2273 0 : perf_cgroup_event_disable(event, ctx);
2274 0 : state = PERF_EVENT_STATE_OFF;
2275 : }
2276 0 : perf_event_set_state(event, state);
2277 :
2278 0 : if (!is_software_event(event))
2279 0 : cpuctx->active_oncpu--;
2280 0 : if (!--ctx->nr_active)
2281 0 : perf_event_ctx_deactivate(ctx);
2282 0 : if (event->attr.freq && event->attr.sample_freq)
2283 0 : ctx->nr_freq--;
2284 0 : if (event->attr.exclusive || !cpuctx->active_oncpu)
2285 0 : cpuctx->exclusive = 0;
2286 :
2287 0 : perf_pmu_enable(event->pmu);
2288 : }
2289 :
2290 : static void
2291 0 : group_sched_out(struct perf_event *group_event,
2292 : struct perf_cpu_context *cpuctx,
2293 : struct perf_event_context *ctx)
2294 : {
2295 0 : struct perf_event *event;
2296 :
2297 0 : if (group_event->state != PERF_EVENT_STATE_ACTIVE)
2298 : return;
2299 :
2300 0 : perf_pmu_disable(ctx->pmu);
2301 :
2302 0 : event_sched_out(group_event, cpuctx, ctx);
2303 :
2304 : /*
2305 : * Schedule out siblings (if any):
2306 : */
2307 0 : for_each_sibling_event(event, group_event)
2308 0 : event_sched_out(event, cpuctx, ctx);
2309 :
2310 0 : perf_pmu_enable(ctx->pmu);
2311 : }
2312 :
2313 : #define DETACH_GROUP 0x01UL
2314 :
2315 : /*
2316 : * Cross CPU call to remove a performance event
2317 : *
2318 : * We disable the event on the hardware level first. After that we
2319 : * remove it from the context list.
2320 : */
2321 : static void
2322 0 : __perf_remove_from_context(struct perf_event *event,
2323 : struct perf_cpu_context *cpuctx,
2324 : struct perf_event_context *ctx,
2325 : void *info)
2326 : {
2327 0 : unsigned long flags = (unsigned long)info;
2328 :
2329 0 : if (ctx->is_active & EVENT_TIME) {
2330 0 : update_context_time(ctx);
2331 0 : update_cgrp_time_from_cpuctx(cpuctx);
2332 : }
2333 :
2334 0 : event_sched_out(event, cpuctx, ctx);
2335 0 : if (flags & DETACH_GROUP)
2336 0 : perf_group_detach(event);
2337 0 : list_del_event(event, ctx);
2338 :
2339 0 : if (!ctx->nr_events && ctx->is_active) {
2340 0 : ctx->is_active = 0;
2341 0 : ctx->rotate_necessary = 0;
2342 0 : if (ctx->task) {
2343 0 : WARN_ON_ONCE(cpuctx->task_ctx != ctx);
2344 0 : cpuctx->task_ctx = NULL;
2345 : }
2346 : }
2347 0 : }
2348 :
2349 : /*
2350 : * Remove the event from a task's (or a CPU's) list of events.
2351 : *
2352 : * If event->ctx is a cloned context, callers must make sure that
2353 : * every task struct that event->ctx->task could possibly point to
2354 : * remains valid. This is OK when called from perf_release since
2355 : * that only calls us on the top-level context, which can't be a clone.
2356 : * When called from perf_event_exit_task, it's OK because the
2357 : * context has been detached from its task.
2358 : */
2359 0 : static void perf_remove_from_context(struct perf_event *event, unsigned long flags)
2360 : {
2361 0 : struct perf_event_context *ctx = event->ctx;
2362 :
2363 0 : lockdep_assert_held(&ctx->mutex);
2364 :
2365 0 : event_function_call(event, __perf_remove_from_context, (void *)flags);
2366 :
2367 : /*
2368 : * The above event_function_call() can NO-OP when it hits
2369 : * TASK_TOMBSTONE. In that case we must already have been detached
2370 : * from the context (by perf_event_exit_event()) but the grouping
2371 : * might still be in-tact.
2372 : */
2373 0 : WARN_ON_ONCE(event->attach_state & PERF_ATTACH_CONTEXT);
2374 0 : if ((flags & DETACH_GROUP) &&
2375 0 : (event->attach_state & PERF_ATTACH_GROUP)) {
2376 : /*
2377 : * Since in that case we cannot possibly be scheduled, simply
2378 : * detach now.
2379 : */
2380 0 : raw_spin_lock_irq(&ctx->lock);
2381 0 : perf_group_detach(event);
2382 0 : raw_spin_unlock_irq(&ctx->lock);
2383 : }
2384 0 : }
2385 :
2386 : /*
2387 : * Cross CPU call to disable a performance event
2388 : */
2389 0 : static void __perf_event_disable(struct perf_event *event,
2390 : struct perf_cpu_context *cpuctx,
2391 : struct perf_event_context *ctx,
2392 : void *info)
2393 : {
2394 0 : if (event->state < PERF_EVENT_STATE_INACTIVE)
2395 : return;
2396 :
2397 0 : if (ctx->is_active & EVENT_TIME) {
2398 0 : update_context_time(ctx);
2399 0 : update_cgrp_time_from_event(event);
2400 : }
2401 :
2402 0 : if (event == event->group_leader)
2403 0 : group_sched_out(event, cpuctx, ctx);
2404 : else
2405 0 : event_sched_out(event, cpuctx, ctx);
2406 :
2407 0 : perf_event_set_state(event, PERF_EVENT_STATE_OFF);
2408 0 : perf_cgroup_event_disable(event, ctx);
2409 : }
2410 :
2411 : /*
2412 : * Disable an event.
2413 : *
2414 : * If event->ctx is a cloned context, callers must make sure that
2415 : * every task struct that event->ctx->task could possibly point to
2416 : * remains valid. This condition is satisfied when called through
2417 : * perf_event_for_each_child or perf_event_for_each because they
2418 : * hold the top-level event's child_mutex, so any descendant that
2419 : * goes to exit will block in perf_event_exit_event().
2420 : *
2421 : * When called from perf_pending_event it's OK because event->ctx
2422 : * is the current context on this CPU and preemption is disabled,
2423 : * hence we can't get into perf_event_task_sched_out for this context.
2424 : */
2425 0 : static void _perf_event_disable(struct perf_event *event)
2426 : {
2427 0 : struct perf_event_context *ctx = event->ctx;
2428 :
2429 0 : raw_spin_lock_irq(&ctx->lock);
2430 0 : if (event->state <= PERF_EVENT_STATE_OFF) {
2431 0 : raw_spin_unlock_irq(&ctx->lock);
2432 0 : return;
2433 : }
2434 0 : raw_spin_unlock_irq(&ctx->lock);
2435 :
2436 0 : event_function_call(event, __perf_event_disable, NULL);
2437 : }
2438 :
2439 0 : void perf_event_disable_local(struct perf_event *event)
2440 : {
2441 0 : event_function_local(event, __perf_event_disable, NULL);
2442 0 : }
2443 :
2444 : /*
2445 : * Strictly speaking kernel users cannot create groups and therefore this
2446 : * interface does not need the perf_event_ctx_lock() magic.
2447 : */
2448 0 : void perf_event_disable(struct perf_event *event)
2449 : {
2450 0 : struct perf_event_context *ctx;
2451 :
2452 0 : ctx = perf_event_ctx_lock(event);
2453 0 : _perf_event_disable(event);
2454 0 : perf_event_ctx_unlock(event, ctx);
2455 0 : }
2456 : EXPORT_SYMBOL_GPL(perf_event_disable);
2457 :
2458 0 : void perf_event_disable_inatomic(struct perf_event *event)
2459 : {
2460 0 : WRITE_ONCE(event->pending_disable, smp_processor_id());
2461 : /* can fail, see perf_pending_event_disable() */
2462 0 : irq_work_queue(&event->pending);
2463 0 : }
2464 :
2465 0 : static void perf_set_shadow_time(struct perf_event *event,
2466 : struct perf_event_context *ctx)
2467 : {
2468 : /*
2469 : * use the correct time source for the time snapshot
2470 : *
2471 : * We could get by without this by leveraging the
2472 : * fact that to get to this function, the caller
2473 : * has most likely already called update_context_time()
2474 : * and update_cgrp_time_xx() and thus both timestamp
2475 : * are identical (or very close). Given that tstamp is,
2476 : * already adjusted for cgroup, we could say that:
2477 : * tstamp - ctx->timestamp
2478 : * is equivalent to
2479 : * tstamp - cgrp->timestamp.
2480 : *
2481 : * Then, in perf_output_read(), the calculation would
2482 : * work with no changes because:
2483 : * - event is guaranteed scheduled in
2484 : * - no scheduled out in between
2485 : * - thus the timestamp would be the same
2486 : *
2487 : * But this is a bit hairy.
2488 : *
2489 : * So instead, we have an explicit cgroup call to remain
2490 : * within the time source all along. We believe it
2491 : * is cleaner and simpler to understand.
2492 : */
2493 0 : if (is_cgroup_event(event))
2494 0 : perf_cgroup_set_shadow_time(event, event->tstamp);
2495 : else
2496 0 : event->shadow_ctx_time = event->tstamp - ctx->timestamp;
2497 : }
2498 :
2499 : #define MAX_INTERRUPTS (~0ULL)
2500 :
2501 : static void perf_log_throttle(struct perf_event *event, int enable);
2502 : static void perf_log_itrace_start(struct perf_event *event);
2503 :
2504 : static int
2505 0 : event_sched_in(struct perf_event *event,
2506 : struct perf_cpu_context *cpuctx,
2507 : struct perf_event_context *ctx)
2508 : {
2509 0 : int ret = 0;
2510 :
2511 0 : WARN_ON_ONCE(event->ctx != ctx);
2512 :
2513 0 : lockdep_assert_held(&ctx->lock);
2514 :
2515 0 : if (event->state <= PERF_EVENT_STATE_OFF)
2516 : return 0;
2517 :
2518 0 : WRITE_ONCE(event->oncpu, smp_processor_id());
2519 : /*
2520 : * Order event::oncpu write to happen before the ACTIVE state is
2521 : * visible. This allows perf_event_{stop,read}() to observe the correct
2522 : * ->oncpu if it sees ACTIVE.
2523 : */
2524 0 : smp_wmb();
2525 0 : perf_event_set_state(event, PERF_EVENT_STATE_ACTIVE);
2526 :
2527 : /*
2528 : * Unthrottle events, since we scheduled we might have missed several
2529 : * ticks already, also for a heavily scheduling task there is little
2530 : * guarantee it'll get a tick in a timely manner.
2531 : */
2532 0 : if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
2533 0 : perf_log_throttle(event, 1);
2534 0 : event->hw.interrupts = 0;
2535 : }
2536 :
2537 0 : perf_pmu_disable(event->pmu);
2538 :
2539 0 : perf_set_shadow_time(event, ctx);
2540 :
2541 0 : perf_log_itrace_start(event);
2542 :
2543 0 : if (event->pmu->add(event, PERF_EF_START)) {
2544 0 : perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2545 0 : event->oncpu = -1;
2546 0 : ret = -EAGAIN;
2547 0 : goto out;
2548 : }
2549 :
2550 0 : if (!is_software_event(event))
2551 0 : cpuctx->active_oncpu++;
2552 0 : if (!ctx->nr_active++)
2553 0 : perf_event_ctx_activate(ctx);
2554 0 : if (event->attr.freq && event->attr.sample_freq)
2555 0 : ctx->nr_freq++;
2556 :
2557 0 : if (event->attr.exclusive)
2558 0 : cpuctx->exclusive = 1;
2559 :
2560 0 : out:
2561 0 : perf_pmu_enable(event->pmu);
2562 :
2563 0 : return ret;
2564 : }
2565 :
2566 : static int
2567 0 : group_sched_in(struct perf_event *group_event,
2568 : struct perf_cpu_context *cpuctx,
2569 : struct perf_event_context *ctx)
2570 : {
2571 0 : struct perf_event *event, *partial_group = NULL;
2572 0 : struct pmu *pmu = ctx->pmu;
2573 :
2574 0 : if (group_event->state == PERF_EVENT_STATE_OFF)
2575 : return 0;
2576 :
2577 0 : pmu->start_txn(pmu, PERF_PMU_TXN_ADD);
2578 :
2579 0 : if (event_sched_in(group_event, cpuctx, ctx))
2580 0 : goto error;
2581 :
2582 : /*
2583 : * Schedule in siblings as one group (if any):
2584 : */
2585 0 : for_each_sibling_event(event, group_event) {
2586 0 : if (event_sched_in(event, cpuctx, ctx)) {
2587 0 : partial_group = event;
2588 0 : goto group_error;
2589 : }
2590 : }
2591 :
2592 0 : if (!pmu->commit_txn(pmu))
2593 : return 0;
2594 :
2595 0 : group_error:
2596 : /*
2597 : * Groups can be scheduled in as one unit only, so undo any
2598 : * partial group before returning:
2599 : * The events up to the failed event are scheduled out normally.
2600 : */
2601 0 : for_each_sibling_event(event, group_event) {
2602 0 : if (event == partial_group)
2603 : break;
2604 :
2605 0 : event_sched_out(event, cpuctx, ctx);
2606 : }
2607 0 : event_sched_out(group_event, cpuctx, ctx);
2608 :
2609 0 : error:
2610 0 : pmu->cancel_txn(pmu);
2611 0 : return -EAGAIN;
2612 : }
2613 :
2614 : /*
2615 : * Work out whether we can put this event group on the CPU now.
2616 : */
2617 0 : static int group_can_go_on(struct perf_event *event,
2618 : struct perf_cpu_context *cpuctx,
2619 : int can_add_hw)
2620 : {
2621 : /*
2622 : * Groups consisting entirely of software events can always go on.
2623 : */
2624 0 : if (event->group_caps & PERF_EV_CAP_SOFTWARE)
2625 : return 1;
2626 : /*
2627 : * If an exclusive group is already on, no other hardware
2628 : * events can go on.
2629 : */
2630 0 : if (cpuctx->exclusive)
2631 : return 0;
2632 : /*
2633 : * If this group is exclusive and there are already
2634 : * events on the CPU, it can't go on.
2635 : */
2636 0 : if (event->attr.exclusive && !list_empty(get_event_list(event)))
2637 0 : return 0;
2638 : /*
2639 : * Otherwise, try to add it if all previous groups were able
2640 : * to go on.
2641 : */
2642 : return can_add_hw;
2643 : }
2644 :
2645 0 : static void add_event_to_ctx(struct perf_event *event,
2646 : struct perf_event_context *ctx)
2647 : {
2648 0 : list_add_event(event, ctx);
2649 0 : perf_group_attach(event);
2650 0 : }
2651 :
2652 : static void ctx_sched_out(struct perf_event_context *ctx,
2653 : struct perf_cpu_context *cpuctx,
2654 : enum event_type_t event_type);
2655 : static void
2656 : ctx_sched_in(struct perf_event_context *ctx,
2657 : struct perf_cpu_context *cpuctx,
2658 : enum event_type_t event_type,
2659 : struct task_struct *task);
2660 :
2661 0 : static void task_ctx_sched_out(struct perf_cpu_context *cpuctx,
2662 : struct perf_event_context *ctx,
2663 : enum event_type_t event_type)
2664 : {
2665 0 : if (!cpuctx->task_ctx)
2666 : return;
2667 :
2668 0 : if (WARN_ON_ONCE(ctx != cpuctx->task_ctx))
2669 : return;
2670 :
2671 0 : ctx_sched_out(ctx, cpuctx, event_type);
2672 : }
2673 :
2674 0 : static void perf_event_sched_in(struct perf_cpu_context *cpuctx,
2675 : struct perf_event_context *ctx,
2676 : struct task_struct *task)
2677 : {
2678 0 : cpu_ctx_sched_in(cpuctx, EVENT_PINNED, task);
2679 0 : if (ctx)
2680 0 : ctx_sched_in(ctx, cpuctx, EVENT_PINNED, task);
2681 0 : cpu_ctx_sched_in(cpuctx, EVENT_FLEXIBLE, task);
2682 0 : if (ctx)
2683 0 : ctx_sched_in(ctx, cpuctx, EVENT_FLEXIBLE, task);
2684 0 : }
2685 :
2686 : /*
2687 : * We want to maintain the following priority of scheduling:
2688 : * - CPU pinned (EVENT_CPU | EVENT_PINNED)
2689 : * - task pinned (EVENT_PINNED)
2690 : * - CPU flexible (EVENT_CPU | EVENT_FLEXIBLE)
2691 : * - task flexible (EVENT_FLEXIBLE).
2692 : *
2693 : * In order to avoid unscheduling and scheduling back in everything every
2694 : * time an event is added, only do it for the groups of equal priority and
2695 : * below.
2696 : *
2697 : * This can be called after a batch operation on task events, in which case
2698 : * event_type is a bit mask of the types of events involved. For CPU events,
2699 : * event_type is only either EVENT_PINNED or EVENT_FLEXIBLE.
2700 : */
2701 0 : static void ctx_resched(struct perf_cpu_context *cpuctx,
2702 : struct perf_event_context *task_ctx,
2703 : enum event_type_t event_type)
2704 : {
2705 0 : enum event_type_t ctx_event_type;
2706 0 : bool cpu_event = !!(event_type & EVENT_CPU);
2707 :
2708 : /*
2709 : * If pinned groups are involved, flexible groups also need to be
2710 : * scheduled out.
2711 : */
2712 0 : if (event_type & EVENT_PINNED)
2713 0 : event_type |= EVENT_FLEXIBLE;
2714 :
2715 0 : ctx_event_type = event_type & EVENT_ALL;
2716 :
2717 0 : perf_pmu_disable(cpuctx->ctx.pmu);
2718 0 : if (task_ctx)
2719 0 : task_ctx_sched_out(cpuctx, task_ctx, event_type);
2720 :
2721 : /*
2722 : * Decide which cpu ctx groups to schedule out based on the types
2723 : * of events that caused rescheduling:
2724 : * - EVENT_CPU: schedule out corresponding groups;
2725 : * - EVENT_PINNED task events: schedule out EVENT_FLEXIBLE groups;
2726 : * - otherwise, do nothing more.
2727 : */
2728 0 : if (cpu_event)
2729 0 : cpu_ctx_sched_out(cpuctx, ctx_event_type);
2730 0 : else if (ctx_event_type & EVENT_PINNED)
2731 0 : cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
2732 :
2733 0 : perf_event_sched_in(cpuctx, task_ctx, current);
2734 0 : perf_pmu_enable(cpuctx->ctx.pmu);
2735 0 : }
2736 :
2737 0 : void perf_pmu_resched(struct pmu *pmu)
2738 : {
2739 0 : struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
2740 0 : struct perf_event_context *task_ctx = cpuctx->task_ctx;
2741 :
2742 0 : perf_ctx_lock(cpuctx, task_ctx);
2743 0 : ctx_resched(cpuctx, task_ctx, EVENT_ALL|EVENT_CPU);
2744 0 : perf_ctx_unlock(cpuctx, task_ctx);
2745 0 : }
2746 :
2747 : /*
2748 : * Cross CPU call to install and enable a performance event
2749 : *
2750 : * Very similar to remote_function() + event_function() but cannot assume that
2751 : * things like ctx->is_active and cpuctx->task_ctx are set.
2752 : */
2753 0 : static int __perf_install_in_context(void *info)
2754 : {
2755 0 : struct perf_event *event = info;
2756 0 : struct perf_event_context *ctx = event->ctx;
2757 0 : struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
2758 0 : struct perf_event_context *task_ctx = cpuctx->task_ctx;
2759 0 : bool reprogram = true;
2760 0 : int ret = 0;
2761 :
2762 0 : raw_spin_lock(&cpuctx->ctx.lock);
2763 0 : if (ctx->task) {
2764 0 : raw_spin_lock(&ctx->lock);
2765 0 : task_ctx = ctx;
2766 :
2767 0 : reprogram = (ctx->task == current);
2768 :
2769 : /*
2770 : * If the task is running, it must be running on this CPU,
2771 : * otherwise we cannot reprogram things.
2772 : *
2773 : * If its not running, we don't care, ctx->lock will
2774 : * serialize against it becoming runnable.
2775 : */
2776 0 : if (task_curr(ctx->task) && !reprogram) {
2777 0 : ret = -ESRCH;
2778 0 : goto unlock;
2779 : }
2780 :
2781 0 : WARN_ON_ONCE(reprogram && cpuctx->task_ctx && cpuctx->task_ctx != ctx);
2782 0 : } else if (task_ctx) {
2783 0 : raw_spin_lock(&task_ctx->lock);
2784 : }
2785 :
2786 : #ifdef CONFIG_CGROUP_PERF
2787 : if (event->state > PERF_EVENT_STATE_OFF && is_cgroup_event(event)) {
2788 : /*
2789 : * If the current cgroup doesn't match the event's
2790 : * cgroup, we should not try to schedule it.
2791 : */
2792 : struct perf_cgroup *cgrp = perf_cgroup_from_task(current, ctx);
2793 : reprogram = cgroup_is_descendant(cgrp->css.cgroup,
2794 : event->cgrp->css.cgroup);
2795 : }
2796 : #endif
2797 :
2798 0 : if (reprogram) {
2799 0 : ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2800 0 : add_event_to_ctx(event, ctx);
2801 0 : ctx_resched(cpuctx, task_ctx, get_event_type(event));
2802 : } else {
2803 0 : add_event_to_ctx(event, ctx);
2804 : }
2805 :
2806 0 : unlock:
2807 0 : perf_ctx_unlock(cpuctx, task_ctx);
2808 :
2809 0 : return ret;
2810 : }
2811 :
2812 : static bool exclusive_event_installable(struct perf_event *event,
2813 : struct perf_event_context *ctx);
2814 :
2815 : /*
2816 : * Attach a performance event to a context.
2817 : *
2818 : * Very similar to event_function_call, see comment there.
2819 : */
2820 : static void
2821 0 : perf_install_in_context(struct perf_event_context *ctx,
2822 : struct perf_event *event,
2823 : int cpu)
2824 : {
2825 0 : struct task_struct *task = READ_ONCE(ctx->task);
2826 :
2827 0 : lockdep_assert_held(&ctx->mutex);
2828 :
2829 0 : WARN_ON_ONCE(!exclusive_event_installable(event, ctx));
2830 :
2831 0 : if (event->cpu != -1)
2832 0 : event->cpu = cpu;
2833 :
2834 : /*
2835 : * Ensures that if we can observe event->ctx, both the event and ctx
2836 : * will be 'complete'. See perf_iterate_sb_cpu().
2837 : */
2838 0 : smp_store_release(&event->ctx, ctx);
2839 :
2840 : /*
2841 : * perf_event_attr::disabled events will not run and can be initialized
2842 : * without IPI. Except when this is the first event for the context, in
2843 : * that case we need the magic of the IPI to set ctx->is_active.
2844 : *
2845 : * The IOC_ENABLE that is sure to follow the creation of a disabled
2846 : * event will issue the IPI and reprogram the hardware.
2847 : */
2848 0 : if (__perf_effective_state(event) == PERF_EVENT_STATE_OFF && ctx->nr_events) {
2849 0 : raw_spin_lock_irq(&ctx->lock);
2850 0 : if (ctx->task == TASK_TOMBSTONE) {
2851 0 : raw_spin_unlock_irq(&ctx->lock);
2852 0 : return;
2853 : }
2854 0 : add_event_to_ctx(event, ctx);
2855 0 : raw_spin_unlock_irq(&ctx->lock);
2856 0 : return;
2857 : }
2858 :
2859 0 : if (!task) {
2860 0 : cpu_function_call(cpu, __perf_install_in_context, event);
2861 0 : return;
2862 : }
2863 :
2864 : /*
2865 : * Should not happen, we validate the ctx is still alive before calling.
2866 : */
2867 0 : if (WARN_ON_ONCE(task == TASK_TOMBSTONE))
2868 : return;
2869 :
2870 : /*
2871 : * Installing events is tricky because we cannot rely on ctx->is_active
2872 : * to be set in case this is the nr_events 0 -> 1 transition.
2873 : *
2874 : * Instead we use task_curr(), which tells us if the task is running.
2875 : * However, since we use task_curr() outside of rq::lock, we can race
2876 : * against the actual state. This means the result can be wrong.
2877 : *
2878 : * If we get a false positive, we retry, this is harmless.
2879 : *
2880 : * If we get a false negative, things are complicated. If we are after
2881 : * perf_event_context_sched_in() ctx::lock will serialize us, and the
2882 : * value must be correct. If we're before, it doesn't matter since
2883 : * perf_event_context_sched_in() will program the counter.
2884 : *
2885 : * However, this hinges on the remote context switch having observed
2886 : * our task->perf_event_ctxp[] store, such that it will in fact take
2887 : * ctx::lock in perf_event_context_sched_in().
2888 : *
2889 : * We do this by task_function_call(), if the IPI fails to hit the task
2890 : * we know any future context switch of task must see the
2891 : * perf_event_ctpx[] store.
2892 : */
2893 :
2894 : /*
2895 : * This smp_mb() orders the task->perf_event_ctxp[] store with the
2896 : * task_cpu() load, such that if the IPI then does not find the task
2897 : * running, a future context switch of that task must observe the
2898 : * store.
2899 : */
2900 0 : smp_mb();
2901 0 : again:
2902 0 : if (!task_function_call(task, __perf_install_in_context, event))
2903 : return;
2904 :
2905 0 : raw_spin_lock_irq(&ctx->lock);
2906 0 : task = ctx->task;
2907 0 : if (WARN_ON_ONCE(task == TASK_TOMBSTONE)) {
2908 : /*
2909 : * Cannot happen because we already checked above (which also
2910 : * cannot happen), and we hold ctx->mutex, which serializes us
2911 : * against perf_event_exit_task_context().
2912 : */
2913 0 : raw_spin_unlock_irq(&ctx->lock);
2914 0 : return;
2915 : }
2916 : /*
2917 : * If the task is not running, ctx->lock will avoid it becoming so,
2918 : * thus we can safely install the event.
2919 : */
2920 0 : if (task_curr(task)) {
2921 0 : raw_spin_unlock_irq(&ctx->lock);
2922 0 : goto again;
2923 : }
2924 0 : add_event_to_ctx(event, ctx);
2925 0 : raw_spin_unlock_irq(&ctx->lock);
2926 : }
2927 :
2928 : /*
2929 : * Cross CPU call to enable a performance event
2930 : */
2931 0 : static void __perf_event_enable(struct perf_event *event,
2932 : struct perf_cpu_context *cpuctx,
2933 : struct perf_event_context *ctx,
2934 : void *info)
2935 : {
2936 0 : struct perf_event *leader = event->group_leader;
2937 0 : struct perf_event_context *task_ctx;
2938 :
2939 0 : if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2940 : event->state <= PERF_EVENT_STATE_ERROR)
2941 : return;
2942 :
2943 0 : if (ctx->is_active)
2944 0 : ctx_sched_out(ctx, cpuctx, EVENT_TIME);
2945 :
2946 0 : perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
2947 0 : perf_cgroup_event_enable(event, ctx);
2948 :
2949 0 : if (!ctx->is_active)
2950 : return;
2951 :
2952 0 : if (!event_filter_match(event)) {
2953 0 : ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2954 0 : return;
2955 : }
2956 :
2957 : /*
2958 : * If the event is in a group and isn't the group leader,
2959 : * then don't put it on unless the group is on.
2960 : */
2961 0 : if (leader != event && leader->state != PERF_EVENT_STATE_ACTIVE) {
2962 0 : ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
2963 0 : return;
2964 : }
2965 :
2966 0 : task_ctx = cpuctx->task_ctx;
2967 0 : if (ctx->task)
2968 0 : WARN_ON_ONCE(task_ctx != ctx);
2969 :
2970 0 : ctx_resched(cpuctx, task_ctx, get_event_type(event));
2971 : }
2972 :
2973 : /*
2974 : * Enable an event.
2975 : *
2976 : * If event->ctx is a cloned context, callers must make sure that
2977 : * every task struct that event->ctx->task could possibly point to
2978 : * remains valid. This condition is satisfied when called through
2979 : * perf_event_for_each_child or perf_event_for_each as described
2980 : * for perf_event_disable.
2981 : */
2982 0 : static void _perf_event_enable(struct perf_event *event)
2983 : {
2984 0 : struct perf_event_context *ctx = event->ctx;
2985 :
2986 0 : raw_spin_lock_irq(&ctx->lock);
2987 0 : if (event->state >= PERF_EVENT_STATE_INACTIVE ||
2988 : event->state < PERF_EVENT_STATE_ERROR) {
2989 0 : out:
2990 0 : raw_spin_unlock_irq(&ctx->lock);
2991 0 : return;
2992 : }
2993 :
2994 : /*
2995 : * If the event is in error state, clear that first.
2996 : *
2997 : * That way, if we see the event in error state below, we know that it
2998 : * has gone back into error state, as distinct from the task having
2999 : * been scheduled away before the cross-call arrived.
3000 : */
3001 0 : if (event->state == PERF_EVENT_STATE_ERROR) {
3002 : /*
3003 : * Detached SIBLING events cannot leave ERROR state.
3004 : */
3005 0 : if (event->event_caps & PERF_EV_CAP_SIBLING &&
3006 0 : event->group_leader == event)
3007 0 : goto out;
3008 :
3009 0 : event->state = PERF_EVENT_STATE_OFF;
3010 : }
3011 0 : raw_spin_unlock_irq(&ctx->lock);
3012 :
3013 0 : event_function_call(event, __perf_event_enable, NULL);
3014 : }
3015 :
3016 : /*
3017 : * See perf_event_disable();
3018 : */
3019 0 : void perf_event_enable(struct perf_event *event)
3020 : {
3021 0 : struct perf_event_context *ctx;
3022 :
3023 0 : ctx = perf_event_ctx_lock(event);
3024 0 : _perf_event_enable(event);
3025 0 : perf_event_ctx_unlock(event, ctx);
3026 0 : }
3027 : EXPORT_SYMBOL_GPL(perf_event_enable);
3028 :
3029 : struct stop_event_data {
3030 : struct perf_event *event;
3031 : unsigned int restart;
3032 : };
3033 :
3034 0 : static int __perf_event_stop(void *info)
3035 : {
3036 0 : struct stop_event_data *sd = info;
3037 0 : struct perf_event *event = sd->event;
3038 :
3039 : /* if it's already INACTIVE, do nothing */
3040 0 : if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
3041 : return 0;
3042 :
3043 : /* matches smp_wmb() in event_sched_in() */
3044 0 : smp_rmb();
3045 :
3046 : /*
3047 : * There is a window with interrupts enabled before we get here,
3048 : * so we need to check again lest we try to stop another CPU's event.
3049 : */
3050 0 : if (READ_ONCE(event->oncpu) != smp_processor_id())
3051 : return -EAGAIN;
3052 :
3053 0 : event->pmu->stop(event, PERF_EF_UPDATE);
3054 :
3055 : /*
3056 : * May race with the actual stop (through perf_pmu_output_stop()),
3057 : * but it is only used for events with AUX ring buffer, and such
3058 : * events will refuse to restart because of rb::aux_mmap_count==0,
3059 : * see comments in perf_aux_output_begin().
3060 : *
3061 : * Since this is happening on an event-local CPU, no trace is lost
3062 : * while restarting.
3063 : */
3064 0 : if (sd->restart)
3065 0 : event->pmu->start(event, 0);
3066 :
3067 : return 0;
3068 : }
3069 :
3070 0 : static int perf_event_stop(struct perf_event *event, int restart)
3071 : {
3072 0 : struct stop_event_data sd = {
3073 : .event = event,
3074 : .restart = restart,
3075 : };
3076 0 : int ret = 0;
3077 :
3078 0 : do {
3079 0 : if (READ_ONCE(event->state) != PERF_EVENT_STATE_ACTIVE)
3080 : return 0;
3081 :
3082 : /* matches smp_wmb() in event_sched_in() */
3083 0 : smp_rmb();
3084 :
3085 : /*
3086 : * We only want to restart ACTIVE events, so if the event goes
3087 : * inactive here (event->oncpu==-1), there's nothing more to do;
3088 : * fall through with ret==-ENXIO.
3089 : */
3090 0 : ret = cpu_function_call(READ_ONCE(event->oncpu),
3091 : __perf_event_stop, &sd);
3092 0 : } while (ret == -EAGAIN);
3093 :
3094 : return ret;
3095 : }
3096 :
3097 : /*
3098 : * In order to contain the amount of racy and tricky in the address filter
3099 : * configuration management, it is a two part process:
3100 : *
3101 : * (p1) when userspace mappings change as a result of (1) or (2) or (3) below,
3102 : * we update the addresses of corresponding vmas in
3103 : * event::addr_filter_ranges array and bump the event::addr_filters_gen;
3104 : * (p2) when an event is scheduled in (pmu::add), it calls
3105 : * perf_event_addr_filters_sync() which calls pmu::addr_filters_sync()
3106 : * if the generation has changed since the previous call.
3107 : *
3108 : * If (p1) happens while the event is active, we restart it to force (p2).
3109 : *
3110 : * (1) perf_addr_filters_apply(): adjusting filters' offsets based on
3111 : * pre-existing mappings, called once when new filters arrive via SET_FILTER
3112 : * ioctl;
3113 : * (2) perf_addr_filters_adjust(): adjusting filters' offsets based on newly
3114 : * registered mapping, called for every new mmap(), with mm::mmap_lock down
3115 : * for reading;
3116 : * (3) perf_event_addr_filters_exec(): clearing filters' offsets in the process
3117 : * of exec.
3118 : */
3119 0 : void perf_event_addr_filters_sync(struct perf_event *event)
3120 : {
3121 0 : struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
3122 :
3123 0 : if (!has_addr_filter(event))
3124 : return;
3125 :
3126 0 : raw_spin_lock(&ifh->lock);
3127 0 : if (event->addr_filters_gen != event->hw.addr_filters_gen) {
3128 0 : event->pmu->addr_filters_sync(event);
3129 0 : event->hw.addr_filters_gen = event->addr_filters_gen;
3130 : }
3131 0 : raw_spin_unlock(&ifh->lock);
3132 : }
3133 : EXPORT_SYMBOL_GPL(perf_event_addr_filters_sync);
3134 :
3135 0 : static int _perf_event_refresh(struct perf_event *event, int refresh)
3136 : {
3137 : /*
3138 : * not supported on inherited events
3139 : */
3140 0 : if (event->attr.inherit || !is_sampling_event(event))
3141 : return -EINVAL;
3142 :
3143 0 : atomic_add(refresh, &event->event_limit);
3144 0 : _perf_event_enable(event);
3145 :
3146 0 : return 0;
3147 : }
3148 :
3149 : /*
3150 : * See perf_event_disable()
3151 : */
3152 0 : int perf_event_refresh(struct perf_event *event, int refresh)
3153 : {
3154 0 : struct perf_event_context *ctx;
3155 0 : int ret;
3156 :
3157 0 : ctx = perf_event_ctx_lock(event);
3158 0 : ret = _perf_event_refresh(event, refresh);
3159 0 : perf_event_ctx_unlock(event, ctx);
3160 :
3161 0 : return ret;
3162 : }
3163 : EXPORT_SYMBOL_GPL(perf_event_refresh);
3164 :
3165 0 : static int perf_event_modify_breakpoint(struct perf_event *bp,
3166 : struct perf_event_attr *attr)
3167 : {
3168 0 : int err;
3169 :
3170 0 : _perf_event_disable(bp);
3171 :
3172 0 : err = modify_user_hw_breakpoint_check(bp, attr, true);
3173 :
3174 0 : if (!bp->attr.disabled)
3175 0 : _perf_event_enable(bp);
3176 :
3177 0 : return err;
3178 : }
3179 :
3180 0 : static int perf_event_modify_attr(struct perf_event *event,
3181 : struct perf_event_attr *attr)
3182 : {
3183 0 : if (event->attr.type != attr->type)
3184 : return -EINVAL;
3185 :
3186 0 : switch (event->attr.type) {
3187 0 : case PERF_TYPE_BREAKPOINT:
3188 0 : return perf_event_modify_breakpoint(event, attr);
3189 : default:
3190 : /* Place holder for future additions. */
3191 : return -EOPNOTSUPP;
3192 : }
3193 : }
3194 :
3195 0 : static void ctx_sched_out(struct perf_event_context *ctx,
3196 : struct perf_cpu_context *cpuctx,
3197 : enum event_type_t event_type)
3198 : {
3199 0 : struct perf_event *event, *tmp;
3200 0 : int is_active = ctx->is_active;
3201 :
3202 0 : lockdep_assert_held(&ctx->lock);
3203 :
3204 0 : if (likely(!ctx->nr_events)) {
3205 : /*
3206 : * See __perf_remove_from_context().
3207 : */
3208 0 : WARN_ON_ONCE(ctx->is_active);
3209 0 : if (ctx->task)
3210 0 : WARN_ON_ONCE(cpuctx->task_ctx);
3211 : return;
3212 : }
3213 :
3214 0 : ctx->is_active &= ~event_type;
3215 0 : if (!(ctx->is_active & EVENT_ALL))
3216 0 : ctx->is_active = 0;
3217 :
3218 0 : if (ctx->task) {
3219 0 : WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3220 0 : if (!ctx->is_active)
3221 0 : cpuctx->task_ctx = NULL;
3222 : }
3223 :
3224 : /*
3225 : * Always update time if it was set; not only when it changes.
3226 : * Otherwise we can 'forget' to update time for any but the last
3227 : * context we sched out. For example:
3228 : *
3229 : * ctx_sched_out(.event_type = EVENT_FLEXIBLE)
3230 : * ctx_sched_out(.event_type = EVENT_PINNED)
3231 : *
3232 : * would only update time for the pinned events.
3233 : */
3234 0 : if (is_active & EVENT_TIME) {
3235 : /* update (and stop) ctx time */
3236 0 : update_context_time(ctx);
3237 0 : update_cgrp_time_from_cpuctx(cpuctx);
3238 : }
3239 :
3240 0 : is_active ^= ctx->is_active; /* changed bits */
3241 :
3242 0 : if (!ctx->nr_active || !(is_active & EVENT_ALL))
3243 : return;
3244 :
3245 0 : perf_pmu_disable(ctx->pmu);
3246 0 : if (is_active & EVENT_PINNED) {
3247 0 : list_for_each_entry_safe(event, tmp, &ctx->pinned_active, active_list)
3248 0 : group_sched_out(event, cpuctx, ctx);
3249 : }
3250 :
3251 0 : if (is_active & EVENT_FLEXIBLE) {
3252 0 : list_for_each_entry_safe(event, tmp, &ctx->flexible_active, active_list)
3253 0 : group_sched_out(event, cpuctx, ctx);
3254 :
3255 : /*
3256 : * Since we cleared EVENT_FLEXIBLE, also clear
3257 : * rotate_necessary, is will be reset by
3258 : * ctx_flexible_sched_in() when needed.
3259 : */
3260 0 : ctx->rotate_necessary = 0;
3261 : }
3262 0 : perf_pmu_enable(ctx->pmu);
3263 : }
3264 :
3265 : /*
3266 : * Test whether two contexts are equivalent, i.e. whether they have both been
3267 : * cloned from the same version of the same context.
3268 : *
3269 : * Equivalence is measured using a generation number in the context that is
3270 : * incremented on each modification to it; see unclone_ctx(), list_add_event()
3271 : * and list_del_event().
3272 : */
3273 0 : static int context_equiv(struct perf_event_context *ctx1,
3274 : struct perf_event_context *ctx2)
3275 : {
3276 0 : lockdep_assert_held(&ctx1->lock);
3277 0 : lockdep_assert_held(&ctx2->lock);
3278 :
3279 : /* Pinning disables the swap optimization */
3280 0 : if (ctx1->pin_count || ctx2->pin_count)
3281 : return 0;
3282 :
3283 : /* If ctx1 is the parent of ctx2 */
3284 0 : if (ctx1 == ctx2->parent_ctx && ctx1->generation == ctx2->parent_gen)
3285 : return 1;
3286 :
3287 : /* If ctx2 is the parent of ctx1 */
3288 0 : if (ctx1->parent_ctx == ctx2 && ctx1->parent_gen == ctx2->generation)
3289 : return 1;
3290 :
3291 : /*
3292 : * If ctx1 and ctx2 have the same parent; we flatten the parent
3293 : * hierarchy, see perf_event_init_context().
3294 : */
3295 0 : if (ctx1->parent_ctx && ctx1->parent_ctx == ctx2->parent_ctx &&
3296 0 : ctx1->parent_gen == ctx2->parent_gen)
3297 0 : return 1;
3298 :
3299 : /* Unmatched */
3300 : return 0;
3301 : }
3302 :
3303 0 : static void __perf_event_sync_stat(struct perf_event *event,
3304 : struct perf_event *next_event)
3305 : {
3306 0 : u64 value;
3307 :
3308 0 : if (!event->attr.inherit_stat)
3309 : return;
3310 :
3311 : /*
3312 : * Update the event value, we cannot use perf_event_read()
3313 : * because we're in the middle of a context switch and have IRQs
3314 : * disabled, which upsets smp_call_function_single(), however
3315 : * we know the event must be on the current CPU, therefore we
3316 : * don't need to use it.
3317 : */
3318 0 : if (event->state == PERF_EVENT_STATE_ACTIVE)
3319 0 : event->pmu->read(event);
3320 :
3321 0 : perf_event_update_time(event);
3322 :
3323 : /*
3324 : * In order to keep per-task stats reliable we need to flip the event
3325 : * values when we flip the contexts.
3326 : */
3327 0 : value = local64_read(&next_event->count);
3328 0 : value = local64_xchg(&event->count, value);
3329 0 : local64_set(&next_event->count, value);
3330 :
3331 0 : swap(event->total_time_enabled, next_event->total_time_enabled);
3332 0 : swap(event->total_time_running, next_event->total_time_running);
3333 :
3334 : /*
3335 : * Since we swizzled the values, update the user visible data too.
3336 : */
3337 0 : perf_event_update_userpage(event);
3338 0 : perf_event_update_userpage(next_event);
3339 : }
3340 :
3341 0 : static void perf_event_sync_stat(struct perf_event_context *ctx,
3342 : struct perf_event_context *next_ctx)
3343 : {
3344 0 : struct perf_event *event, *next_event;
3345 :
3346 0 : if (!ctx->nr_stat)
3347 : return;
3348 :
3349 0 : update_context_time(ctx);
3350 :
3351 0 : event = list_first_entry(&ctx->event_list,
3352 : struct perf_event, event_entry);
3353 :
3354 0 : next_event = list_first_entry(&next_ctx->event_list,
3355 : struct perf_event, event_entry);
3356 :
3357 0 : while (&event->event_entry != &ctx->event_list &&
3358 0 : &next_event->event_entry != &next_ctx->event_list) {
3359 :
3360 0 : __perf_event_sync_stat(event, next_event);
3361 :
3362 0 : event = list_next_entry(event, event_entry);
3363 0 : next_event = list_next_entry(next_event, event_entry);
3364 : }
3365 : }
3366 :
3367 0 : static void perf_event_context_sched_out(struct task_struct *task, int ctxn,
3368 : struct task_struct *next)
3369 : {
3370 0 : struct perf_event_context *ctx = task->perf_event_ctxp[ctxn];
3371 0 : struct perf_event_context *next_ctx;
3372 0 : struct perf_event_context *parent, *next_parent;
3373 0 : struct perf_cpu_context *cpuctx;
3374 0 : int do_switch = 1;
3375 0 : struct pmu *pmu;
3376 :
3377 0 : if (likely(!ctx))
3378 : return;
3379 :
3380 0 : pmu = ctx->pmu;
3381 0 : cpuctx = __get_cpu_context(ctx);
3382 0 : if (!cpuctx->task_ctx)
3383 : return;
3384 :
3385 0 : rcu_read_lock();
3386 0 : next_ctx = next->perf_event_ctxp[ctxn];
3387 0 : if (!next_ctx)
3388 0 : goto unlock;
3389 :
3390 0 : parent = rcu_dereference(ctx->parent_ctx);
3391 0 : next_parent = rcu_dereference(next_ctx->parent_ctx);
3392 :
3393 : /* If neither context have a parent context; they cannot be clones. */
3394 0 : if (!parent && !next_parent)
3395 0 : goto unlock;
3396 :
3397 0 : if (next_parent == ctx || next_ctx == parent || next_parent == parent) {
3398 : /*
3399 : * Looks like the two contexts are clones, so we might be
3400 : * able to optimize the context switch. We lock both
3401 : * contexts and check that they are clones under the
3402 : * lock (including re-checking that neither has been
3403 : * uncloned in the meantime). It doesn't matter which
3404 : * order we take the locks because no other cpu could
3405 : * be trying to lock both of these tasks.
3406 : */
3407 0 : raw_spin_lock(&ctx->lock);
3408 0 : raw_spin_lock_nested(&next_ctx->lock, SINGLE_DEPTH_NESTING);
3409 0 : if (context_equiv(ctx, next_ctx)) {
3410 :
3411 0 : WRITE_ONCE(ctx->task, next);
3412 0 : WRITE_ONCE(next_ctx->task, task);
3413 :
3414 0 : perf_pmu_disable(pmu);
3415 :
3416 0 : if (cpuctx->sched_cb_usage && pmu->sched_task)
3417 0 : pmu->sched_task(ctx, false);
3418 :
3419 : /*
3420 : * PMU specific parts of task perf context can require
3421 : * additional synchronization. As an example of such
3422 : * synchronization see implementation details of Intel
3423 : * LBR call stack data profiling;
3424 : */
3425 0 : if (pmu->swap_task_ctx)
3426 0 : pmu->swap_task_ctx(ctx, next_ctx);
3427 : else
3428 0 : swap(ctx->task_ctx_data, next_ctx->task_ctx_data);
3429 :
3430 0 : perf_pmu_enable(pmu);
3431 :
3432 : /*
3433 : * RCU_INIT_POINTER here is safe because we've not
3434 : * modified the ctx and the above modification of
3435 : * ctx->task and ctx->task_ctx_data are immaterial
3436 : * since those values are always verified under
3437 : * ctx->lock which we're now holding.
3438 : */
3439 0 : RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], next_ctx);
3440 0 : RCU_INIT_POINTER(next->perf_event_ctxp[ctxn], ctx);
3441 :
3442 0 : do_switch = 0;
3443 :
3444 0 : perf_event_sync_stat(ctx, next_ctx);
3445 : }
3446 0 : raw_spin_unlock(&next_ctx->lock);
3447 0 : raw_spin_unlock(&ctx->lock);
3448 : }
3449 0 : unlock:
3450 0 : rcu_read_unlock();
3451 :
3452 0 : if (do_switch) {
3453 0 : raw_spin_lock(&ctx->lock);
3454 0 : perf_pmu_disable(pmu);
3455 :
3456 0 : if (cpuctx->sched_cb_usage && pmu->sched_task)
3457 0 : pmu->sched_task(ctx, false);
3458 0 : task_ctx_sched_out(cpuctx, ctx, EVENT_ALL);
3459 :
3460 0 : perf_pmu_enable(pmu);
3461 0 : raw_spin_unlock(&ctx->lock);
3462 : }
3463 : }
3464 :
3465 : static DEFINE_PER_CPU(struct list_head, sched_cb_list);
3466 :
3467 0 : void perf_sched_cb_dec(struct pmu *pmu)
3468 : {
3469 0 : struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3470 :
3471 0 : this_cpu_dec(perf_sched_cb_usages);
3472 :
3473 0 : if (!--cpuctx->sched_cb_usage)
3474 0 : list_del(&cpuctx->sched_cb_entry);
3475 0 : }
3476 :
3477 :
3478 0 : void perf_sched_cb_inc(struct pmu *pmu)
3479 : {
3480 0 : struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
3481 :
3482 0 : if (!cpuctx->sched_cb_usage++)
3483 0 : list_add(&cpuctx->sched_cb_entry, this_cpu_ptr(&sched_cb_list));
3484 :
3485 0 : this_cpu_inc(perf_sched_cb_usages);
3486 0 : }
3487 :
3488 : /*
3489 : * This function provides the context switch callback to the lower code
3490 : * layer. It is invoked ONLY when the context switch callback is enabled.
3491 : *
3492 : * This callback is relevant even to per-cpu events; for example multi event
3493 : * PEBS requires this to provide PID/TID information. This requires we flush
3494 : * all queued PEBS records before we context switch to a new task.
3495 : */
3496 0 : static void __perf_pmu_sched_task(struct perf_cpu_context *cpuctx, bool sched_in)
3497 : {
3498 0 : struct pmu *pmu;
3499 :
3500 0 : pmu = cpuctx->ctx.pmu; /* software PMUs will not have sched_task */
3501 :
3502 0 : if (WARN_ON_ONCE(!pmu->sched_task))
3503 : return;
3504 :
3505 0 : perf_ctx_lock(cpuctx, cpuctx->task_ctx);
3506 0 : perf_pmu_disable(pmu);
3507 :
3508 0 : pmu->sched_task(cpuctx->task_ctx, sched_in);
3509 :
3510 0 : perf_pmu_enable(pmu);
3511 0 : perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
3512 : }
3513 :
3514 0 : static void perf_pmu_sched_task(struct task_struct *prev,
3515 : struct task_struct *next,
3516 : bool sched_in)
3517 : {
3518 0 : struct perf_cpu_context *cpuctx;
3519 :
3520 0 : if (prev == next)
3521 : return;
3522 :
3523 0 : list_for_each_entry(cpuctx, this_cpu_ptr(&sched_cb_list), sched_cb_entry) {
3524 : /* will be handled in perf_event_context_sched_in/out */
3525 0 : if (cpuctx->task_ctx)
3526 0 : continue;
3527 :
3528 0 : __perf_pmu_sched_task(cpuctx, sched_in);
3529 : }
3530 : }
3531 :
3532 : static void perf_event_switch(struct task_struct *task,
3533 : struct task_struct *next_prev, bool sched_in);
3534 :
3535 : #define for_each_task_context_nr(ctxn) \
3536 : for ((ctxn) = 0; (ctxn) < perf_nr_task_contexts; (ctxn)++)
3537 :
3538 : /*
3539 : * Called from scheduler to remove the events of the current task,
3540 : * with interrupts disabled.
3541 : *
3542 : * We stop each event and update the event value in event->count.
3543 : *
3544 : * This does not protect us against NMI, but disable()
3545 : * sets the disabled bit in the control field of event _before_
3546 : * accessing the event control register. If a NMI hits, then it will
3547 : * not restart the event.
3548 : */
3549 0 : void __perf_event_task_sched_out(struct task_struct *task,
3550 : struct task_struct *next)
3551 : {
3552 0 : int ctxn;
3553 :
3554 0 : if (__this_cpu_read(perf_sched_cb_usages))
3555 0 : perf_pmu_sched_task(task, next, false);
3556 :
3557 0 : if (atomic_read(&nr_switch_events))
3558 0 : perf_event_switch(task, next, false);
3559 :
3560 0 : for_each_task_context_nr(ctxn)
3561 0 : perf_event_context_sched_out(task, ctxn, next);
3562 :
3563 : /*
3564 : * if cgroup events exist on this CPU, then we need
3565 : * to check if we have to switch out PMU state.
3566 : * cgroup event are system-wide mode only
3567 : */
3568 0 : if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3569 0 : perf_cgroup_sched_out(task, next);
3570 0 : }
3571 :
3572 : /*
3573 : * Called with IRQs disabled
3574 : */
3575 0 : static void cpu_ctx_sched_out(struct perf_cpu_context *cpuctx,
3576 : enum event_type_t event_type)
3577 : {
3578 0 : ctx_sched_out(&cpuctx->ctx, cpuctx, event_type);
3579 0 : }
3580 :
3581 0 : static bool perf_less_group_idx(const void *l, const void *r)
3582 : {
3583 0 : const struct perf_event *le = *(const struct perf_event **)l;
3584 0 : const struct perf_event *re = *(const struct perf_event **)r;
3585 :
3586 0 : return le->group_index < re->group_index;
3587 : }
3588 :
3589 0 : static void swap_ptr(void *l, void *r)
3590 : {
3591 0 : void **lp = l, **rp = r;
3592 :
3593 0 : swap(*lp, *rp);
3594 0 : }
3595 :
3596 : static const struct min_heap_callbacks perf_min_heap = {
3597 : .elem_size = sizeof(struct perf_event *),
3598 : .less = perf_less_group_idx,
3599 : .swp = swap_ptr,
3600 : };
3601 :
3602 0 : static void __heap_add(struct min_heap *heap, struct perf_event *event)
3603 : {
3604 0 : struct perf_event **itrs = heap->data;
3605 :
3606 0 : if (event) {
3607 0 : itrs[heap->nr] = event;
3608 0 : heap->nr++;
3609 : }
3610 : }
3611 :
3612 0 : static noinline int visit_groups_merge(struct perf_cpu_context *cpuctx,
3613 : struct perf_event_groups *groups, int cpu,
3614 : int (*func)(struct perf_event *, void *),
3615 : void *data)
3616 : {
3617 : #ifdef CONFIG_CGROUP_PERF
3618 : struct cgroup_subsys_state *css = NULL;
3619 : #endif
3620 : /* Space for per CPU and/or any CPU event iterators. */
3621 0 : struct perf_event *itrs[2];
3622 0 : struct min_heap event_heap;
3623 0 : struct perf_event **evt;
3624 0 : int ret;
3625 :
3626 0 : if (cpuctx) {
3627 0 : event_heap = (struct min_heap){
3628 0 : .data = cpuctx->heap,
3629 : .nr = 0,
3630 0 : .size = cpuctx->heap_size,
3631 : };
3632 :
3633 0 : lockdep_assert_held(&cpuctx->ctx.lock);
3634 :
3635 : #ifdef CONFIG_CGROUP_PERF
3636 : if (cpuctx->cgrp)
3637 : css = &cpuctx->cgrp->css;
3638 : #endif
3639 : } else {
3640 0 : event_heap = (struct min_heap){
3641 : .data = itrs,
3642 : .nr = 0,
3643 : .size = ARRAY_SIZE(itrs),
3644 : };
3645 : /* Events not within a CPU context may be on any CPU. */
3646 0 : __heap_add(&event_heap, perf_event_groups_first(groups, -1, NULL));
3647 : }
3648 0 : evt = event_heap.data;
3649 :
3650 0 : __heap_add(&event_heap, perf_event_groups_first(groups, cpu, NULL));
3651 :
3652 : #ifdef CONFIG_CGROUP_PERF
3653 : for (; css; css = css->parent)
3654 : __heap_add(&event_heap, perf_event_groups_first(groups, cpu, css->cgroup));
3655 : #endif
3656 :
3657 0 : min_heapify_all(&event_heap, &perf_min_heap);
3658 :
3659 0 : while (event_heap.nr) {
3660 0 : ret = func(*evt, data);
3661 0 : if (ret)
3662 0 : return ret;
3663 :
3664 0 : *evt = perf_event_groups_next(*evt);
3665 0 : if (*evt)
3666 0 : min_heapify(&event_heap, 0, &perf_min_heap);
3667 : else
3668 0 : min_heap_pop(&event_heap, &perf_min_heap);
3669 : }
3670 :
3671 : return 0;
3672 : }
3673 :
3674 0 : static int merge_sched_in(struct perf_event *event, void *data)
3675 : {
3676 0 : struct perf_event_context *ctx = event->ctx;
3677 0 : struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
3678 0 : int *can_add_hw = data;
3679 :
3680 0 : if (event->state <= PERF_EVENT_STATE_OFF)
3681 : return 0;
3682 :
3683 0 : if (!event_filter_match(event))
3684 : return 0;
3685 :
3686 0 : if (group_can_go_on(event, cpuctx, *can_add_hw)) {
3687 0 : if (!group_sched_in(event, cpuctx, ctx))
3688 0 : list_add_tail(&event->active_list, get_event_list(event));
3689 : }
3690 :
3691 0 : if (event->state == PERF_EVENT_STATE_INACTIVE) {
3692 0 : if (event->attr.pinned) {
3693 0 : perf_cgroup_event_disable(event, ctx);
3694 0 : perf_event_set_state(event, PERF_EVENT_STATE_ERROR);
3695 : }
3696 :
3697 0 : *can_add_hw = 0;
3698 0 : ctx->rotate_necessary = 1;
3699 0 : perf_mux_hrtimer_restart(cpuctx);
3700 : }
3701 :
3702 : return 0;
3703 : }
3704 :
3705 : static void
3706 0 : ctx_pinned_sched_in(struct perf_event_context *ctx,
3707 : struct perf_cpu_context *cpuctx)
3708 : {
3709 0 : int can_add_hw = 1;
3710 :
3711 0 : if (ctx != &cpuctx->ctx)
3712 0 : cpuctx = NULL;
3713 :
3714 0 : visit_groups_merge(cpuctx, &ctx->pinned_groups,
3715 0 : smp_processor_id(),
3716 : merge_sched_in, &can_add_hw);
3717 0 : }
3718 :
3719 : static void
3720 0 : ctx_flexible_sched_in(struct perf_event_context *ctx,
3721 : struct perf_cpu_context *cpuctx)
3722 : {
3723 0 : int can_add_hw = 1;
3724 :
3725 0 : if (ctx != &cpuctx->ctx)
3726 0 : cpuctx = NULL;
3727 :
3728 0 : visit_groups_merge(cpuctx, &ctx->flexible_groups,
3729 0 : smp_processor_id(),
3730 : merge_sched_in, &can_add_hw);
3731 0 : }
3732 :
3733 : static void
3734 0 : ctx_sched_in(struct perf_event_context *ctx,
3735 : struct perf_cpu_context *cpuctx,
3736 : enum event_type_t event_type,
3737 : struct task_struct *task)
3738 : {
3739 0 : int is_active = ctx->is_active;
3740 0 : u64 now;
3741 :
3742 0 : lockdep_assert_held(&ctx->lock);
3743 :
3744 0 : if (likely(!ctx->nr_events))
3745 : return;
3746 :
3747 0 : ctx->is_active |= (event_type | EVENT_TIME);
3748 0 : if (ctx->task) {
3749 0 : if (!is_active)
3750 0 : cpuctx->task_ctx = ctx;
3751 : else
3752 0 : WARN_ON_ONCE(cpuctx->task_ctx != ctx);
3753 : }
3754 :
3755 0 : is_active ^= ctx->is_active; /* changed bits */
3756 :
3757 0 : if (is_active & EVENT_TIME) {
3758 : /* start ctx time */
3759 0 : now = perf_clock();
3760 0 : ctx->timestamp = now;
3761 0 : perf_cgroup_set_timestamp(task, ctx);
3762 : }
3763 :
3764 : /*
3765 : * First go through the list and put on any pinned groups
3766 : * in order to give them the best chance of going on.
3767 : */
3768 0 : if (is_active & EVENT_PINNED)
3769 0 : ctx_pinned_sched_in(ctx, cpuctx);
3770 :
3771 : /* Then walk through the lower prio flexible groups */
3772 0 : if (is_active & EVENT_FLEXIBLE)
3773 0 : ctx_flexible_sched_in(ctx, cpuctx);
3774 : }
3775 :
3776 0 : static void cpu_ctx_sched_in(struct perf_cpu_context *cpuctx,
3777 : enum event_type_t event_type,
3778 : struct task_struct *task)
3779 : {
3780 0 : struct perf_event_context *ctx = &cpuctx->ctx;
3781 :
3782 0 : ctx_sched_in(ctx, cpuctx, event_type, task);
3783 : }
3784 :
3785 0 : static void perf_event_context_sched_in(struct perf_event_context *ctx,
3786 : struct task_struct *task)
3787 : {
3788 0 : struct perf_cpu_context *cpuctx;
3789 0 : struct pmu *pmu = ctx->pmu;
3790 :
3791 0 : cpuctx = __get_cpu_context(ctx);
3792 0 : if (cpuctx->task_ctx == ctx) {
3793 0 : if (cpuctx->sched_cb_usage)
3794 0 : __perf_pmu_sched_task(cpuctx, true);
3795 0 : return;
3796 : }
3797 :
3798 0 : perf_ctx_lock(cpuctx, ctx);
3799 : /*
3800 : * We must check ctx->nr_events while holding ctx->lock, such
3801 : * that we serialize against perf_install_in_context().
3802 : */
3803 0 : if (!ctx->nr_events)
3804 0 : goto unlock;
3805 :
3806 0 : perf_pmu_disable(pmu);
3807 : /*
3808 : * We want to keep the following priority order:
3809 : * cpu pinned (that don't need to move), task pinned,
3810 : * cpu flexible, task flexible.
3811 : *
3812 : * However, if task's ctx is not carrying any pinned
3813 : * events, no need to flip the cpuctx's events around.
3814 : */
3815 0 : if (!RB_EMPTY_ROOT(&ctx->pinned_groups.tree))
3816 0 : cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
3817 0 : perf_event_sched_in(cpuctx, ctx, task);
3818 :
3819 0 : if (cpuctx->sched_cb_usage && pmu->sched_task)
3820 0 : pmu->sched_task(cpuctx->task_ctx, true);
3821 :
3822 0 : perf_pmu_enable(pmu);
3823 :
3824 0 : unlock:
3825 0 : perf_ctx_unlock(cpuctx, ctx);
3826 : }
3827 :
3828 : /*
3829 : * Called from scheduler to add the events of the current task
3830 : * with interrupts disabled.
3831 : *
3832 : * We restore the event value and then enable it.
3833 : *
3834 : * This does not protect us against NMI, but enable()
3835 : * sets the enabled bit in the control field of event _before_
3836 : * accessing the event control register. If a NMI hits, then it will
3837 : * keep the event running.
3838 : */
3839 0 : void __perf_event_task_sched_in(struct task_struct *prev,
3840 : struct task_struct *task)
3841 : {
3842 0 : struct perf_event_context *ctx;
3843 0 : int ctxn;
3844 :
3845 : /*
3846 : * If cgroup events exist on this CPU, then we need to check if we have
3847 : * to switch in PMU state; cgroup event are system-wide mode only.
3848 : *
3849 : * Since cgroup events are CPU events, we must schedule these in before
3850 : * we schedule in the task events.
3851 : */
3852 0 : if (atomic_read(this_cpu_ptr(&perf_cgroup_events)))
3853 0 : perf_cgroup_sched_in(prev, task);
3854 :
3855 0 : for_each_task_context_nr(ctxn) {
3856 0 : ctx = task->perf_event_ctxp[ctxn];
3857 0 : if (likely(!ctx))
3858 0 : continue;
3859 :
3860 0 : perf_event_context_sched_in(ctx, task);
3861 : }
3862 :
3863 0 : if (atomic_read(&nr_switch_events))
3864 0 : perf_event_switch(task, prev, true);
3865 :
3866 0 : if (__this_cpu_read(perf_sched_cb_usages))
3867 0 : perf_pmu_sched_task(prev, task, true);
3868 0 : }
3869 :
3870 0 : static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
3871 : {
3872 0 : u64 frequency = event->attr.sample_freq;
3873 0 : u64 sec = NSEC_PER_SEC;
3874 0 : u64 divisor, dividend;
3875 :
3876 0 : int count_fls, nsec_fls, frequency_fls, sec_fls;
3877 :
3878 0 : count_fls = fls64(count);
3879 0 : nsec_fls = fls64(nsec);
3880 0 : frequency_fls = fls64(frequency);
3881 0 : sec_fls = 30;
3882 :
3883 : /*
3884 : * We got @count in @nsec, with a target of sample_freq HZ
3885 : * the target period becomes:
3886 : *
3887 : * @count * 10^9
3888 : * period = -------------------
3889 : * @nsec * sample_freq
3890 : *
3891 : */
3892 :
3893 : /*
3894 : * Reduce accuracy by one bit such that @a and @b converge
3895 : * to a similar magnitude.
3896 : */
3897 : #define REDUCE_FLS(a, b) \
3898 : do { \
3899 : if (a##_fls > b##_fls) { \
3900 : a >>= 1; \
3901 : a##_fls--; \
3902 : } else { \
3903 : b >>= 1; \
3904 : b##_fls--; \
3905 : } \
3906 : } while (0)
3907 :
3908 : /*
3909 : * Reduce accuracy until either term fits in a u64, then proceed with
3910 : * the other, so that finally we can do a u64/u64 division.
3911 : */
3912 0 : while (count_fls + sec_fls > 64 && nsec_fls + frequency_fls > 64) {
3913 0 : REDUCE_FLS(nsec, frequency);
3914 0 : REDUCE_FLS(sec, count);
3915 : }
3916 :
3917 0 : if (count_fls + sec_fls > 64) {
3918 0 : divisor = nsec * frequency;
3919 :
3920 0 : while (count_fls + sec_fls > 64) {
3921 0 : REDUCE_FLS(count, sec);
3922 0 : divisor >>= 1;
3923 : }
3924 :
3925 0 : dividend = count * sec;
3926 : } else {
3927 0 : dividend = count * sec;
3928 :
3929 0 : while (nsec_fls + frequency_fls > 64) {
3930 0 : REDUCE_FLS(nsec, frequency);
3931 0 : dividend >>= 1;
3932 : }
3933 :
3934 0 : divisor = nsec * frequency;
3935 : }
3936 :
3937 0 : if (!divisor)
3938 : return dividend;
3939 :
3940 0 : return div64_u64(dividend, divisor);
3941 : }
3942 :
3943 : static DEFINE_PER_CPU(int, perf_throttled_count);
3944 : static DEFINE_PER_CPU(u64, perf_throttled_seq);
3945 :
3946 0 : static void perf_adjust_period(struct perf_event *event, u64 nsec, u64 count, bool disable)
3947 : {
3948 0 : struct hw_perf_event *hwc = &event->hw;
3949 0 : s64 period, sample_period;
3950 0 : s64 delta;
3951 :
3952 0 : period = perf_calculate_period(event, nsec, count);
3953 :
3954 0 : delta = (s64)(period - hwc->sample_period);
3955 0 : delta = (delta + 7) / 8; /* low pass filter */
3956 :
3957 0 : sample_period = hwc->sample_period + delta;
3958 :
3959 0 : if (!sample_period)
3960 0 : sample_period = 1;
3961 :
3962 0 : hwc->sample_period = sample_period;
3963 :
3964 0 : if (local64_read(&hwc->period_left) > 8*sample_period) {
3965 0 : if (disable)
3966 0 : event->pmu->stop(event, PERF_EF_UPDATE);
3967 :
3968 0 : local64_set(&hwc->period_left, 0);
3969 :
3970 0 : if (disable)
3971 0 : event->pmu->start(event, PERF_EF_RELOAD);
3972 : }
3973 0 : }
3974 :
3975 : /*
3976 : * combine freq adjustment with unthrottling to avoid two passes over the
3977 : * events. At the same time, make sure, having freq events does not change
3978 : * the rate of unthrottling as that would introduce bias.
3979 : */
3980 0 : static void perf_adjust_freq_unthr_context(struct perf_event_context *ctx,
3981 : int needs_unthr)
3982 : {
3983 0 : struct perf_event *event;
3984 0 : struct hw_perf_event *hwc;
3985 0 : u64 now, period = TICK_NSEC;
3986 0 : s64 delta;
3987 :
3988 : /*
3989 : * only need to iterate over all events iff:
3990 : * - context have events in frequency mode (needs freq adjust)
3991 : * - there are events to unthrottle on this cpu
3992 : */
3993 0 : if (!(ctx->nr_freq || needs_unthr))
3994 : return;
3995 :
3996 0 : raw_spin_lock(&ctx->lock);
3997 0 : perf_pmu_disable(ctx->pmu);
3998 :
3999 0 : list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
4000 0 : if (event->state != PERF_EVENT_STATE_ACTIVE)
4001 0 : continue;
4002 :
4003 0 : if (!event_filter_match(event))
4004 0 : continue;
4005 :
4006 0 : perf_pmu_disable(event->pmu);
4007 :
4008 0 : hwc = &event->hw;
4009 :
4010 0 : if (hwc->interrupts == MAX_INTERRUPTS) {
4011 0 : hwc->interrupts = 0;
4012 0 : perf_log_throttle(event, 1);
4013 0 : event->pmu->start(event, 0);
4014 : }
4015 :
4016 0 : if (!event->attr.freq || !event->attr.sample_freq)
4017 0 : goto next;
4018 :
4019 : /*
4020 : * stop the event and update event->count
4021 : */
4022 0 : event->pmu->stop(event, PERF_EF_UPDATE);
4023 :
4024 0 : now = local64_read(&event->count);
4025 0 : delta = now - hwc->freq_count_stamp;
4026 0 : hwc->freq_count_stamp = now;
4027 :
4028 : /*
4029 : * restart the event
4030 : * reload only if value has changed
4031 : * we have stopped the event so tell that
4032 : * to perf_adjust_period() to avoid stopping it
4033 : * twice.
4034 : */
4035 0 : if (delta > 0)
4036 0 : perf_adjust_period(event, period, delta, false);
4037 :
4038 0 : event->pmu->start(event, delta > 0 ? PERF_EF_RELOAD : 0);
4039 0 : next:
4040 0 : perf_pmu_enable(event->pmu);
4041 : }
4042 :
4043 0 : perf_pmu_enable(ctx->pmu);
4044 0 : raw_spin_unlock(&ctx->lock);
4045 : }
4046 :
4047 : /*
4048 : * Move @event to the tail of the @ctx's elegible events.
4049 : */
4050 0 : static void rotate_ctx(struct perf_event_context *ctx, struct perf_event *event)
4051 : {
4052 : /*
4053 : * Rotate the first entry last of non-pinned groups. Rotation might be
4054 : * disabled by the inheritance code.
4055 : */
4056 0 : if (ctx->rotate_disable)
4057 : return;
4058 :
4059 0 : perf_event_groups_delete(&ctx->flexible_groups, event);
4060 0 : perf_event_groups_insert(&ctx->flexible_groups, event);
4061 : }
4062 :
4063 : /* pick an event from the flexible_groups to rotate */
4064 : static inline struct perf_event *
4065 0 : ctx_event_to_rotate(struct perf_event_context *ctx)
4066 : {
4067 0 : struct perf_event *event;
4068 :
4069 : /* pick the first active flexible event */
4070 0 : event = list_first_entry_or_null(&ctx->flexible_active,
4071 : struct perf_event, active_list);
4072 :
4073 : /* if no active flexible event, pick the first event */
4074 0 : if (!event) {
4075 0 : event = rb_entry_safe(rb_first(&ctx->flexible_groups.tree),
4076 : typeof(*event), group_node);
4077 : }
4078 :
4079 : /*
4080 : * Unconditionally clear rotate_necessary; if ctx_flexible_sched_in()
4081 : * finds there are unschedulable events, it will set it again.
4082 : */
4083 0 : ctx->rotate_necessary = 0;
4084 :
4085 0 : return event;
4086 : }
4087 :
4088 0 : static bool perf_rotate_context(struct perf_cpu_context *cpuctx)
4089 : {
4090 0 : struct perf_event *cpu_event = NULL, *task_event = NULL;
4091 0 : struct perf_event_context *task_ctx = NULL;
4092 0 : int cpu_rotate, task_rotate;
4093 :
4094 : /*
4095 : * Since we run this from IRQ context, nobody can install new
4096 : * events, thus the event count values are stable.
4097 : */
4098 :
4099 0 : cpu_rotate = cpuctx->ctx.rotate_necessary;
4100 0 : task_ctx = cpuctx->task_ctx;
4101 0 : task_rotate = task_ctx ? task_ctx->rotate_necessary : 0;
4102 :
4103 0 : if (!(cpu_rotate || task_rotate))
4104 : return false;
4105 :
4106 0 : perf_ctx_lock(cpuctx, cpuctx->task_ctx);
4107 0 : perf_pmu_disable(cpuctx->ctx.pmu);
4108 :
4109 0 : if (task_rotate)
4110 0 : task_event = ctx_event_to_rotate(task_ctx);
4111 0 : if (cpu_rotate)
4112 0 : cpu_event = ctx_event_to_rotate(&cpuctx->ctx);
4113 :
4114 : /*
4115 : * As per the order given at ctx_resched() first 'pop' task flexible
4116 : * and then, if needed CPU flexible.
4117 : */
4118 0 : if (task_event || (task_ctx && cpu_event))
4119 0 : ctx_sched_out(task_ctx, cpuctx, EVENT_FLEXIBLE);
4120 0 : if (cpu_event)
4121 0 : cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
4122 :
4123 0 : if (task_event)
4124 0 : rotate_ctx(task_ctx, task_event);
4125 0 : if (cpu_event)
4126 0 : rotate_ctx(&cpuctx->ctx, cpu_event);
4127 :
4128 0 : perf_event_sched_in(cpuctx, task_ctx, current);
4129 :
4130 0 : perf_pmu_enable(cpuctx->ctx.pmu);
4131 0 : perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
4132 :
4133 0 : return true;
4134 : }
4135 :
4136 32228 : void perf_event_task_tick(void)
4137 : {
4138 32228 : struct list_head *head = this_cpu_ptr(&active_ctx_list);
4139 32415 : struct perf_event_context *ctx, *tmp;
4140 32415 : int throttled;
4141 :
4142 64926 : lockdep_assert_irqs_disabled();
4143 :
4144 32459 : __this_cpu_inc(perf_throttled_seq);
4145 32459 : throttled = __this_cpu_xchg(perf_throttled_count, 0);
4146 32459 : tick_dep_clear_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
4147 :
4148 32459 : list_for_each_entry_safe(ctx, tmp, head, active_ctx_list)
4149 0 : perf_adjust_freq_unthr_context(ctx, throttled);
4150 32463 : }
4151 :
4152 0 : static int event_enable_on_exec(struct perf_event *event,
4153 : struct perf_event_context *ctx)
4154 : {
4155 0 : if (!event->attr.enable_on_exec)
4156 : return 0;
4157 :
4158 0 : event->attr.enable_on_exec = 0;
4159 0 : if (event->state >= PERF_EVENT_STATE_INACTIVE)
4160 : return 0;
4161 :
4162 0 : perf_event_set_state(event, PERF_EVENT_STATE_INACTIVE);
4163 :
4164 0 : return 1;
4165 : }
4166 :
4167 : /*
4168 : * Enable all of a task's events that have been marked enable-on-exec.
4169 : * This expects task == current.
4170 : */
4171 0 : static void perf_event_enable_on_exec(int ctxn)
4172 : {
4173 0 : struct perf_event_context *ctx, *clone_ctx = NULL;
4174 0 : enum event_type_t event_type = 0;
4175 0 : struct perf_cpu_context *cpuctx;
4176 0 : struct perf_event *event;
4177 0 : unsigned long flags;
4178 0 : int enabled = 0;
4179 :
4180 0 : local_irq_save(flags);
4181 0 : ctx = current->perf_event_ctxp[ctxn];
4182 0 : if (!ctx || !ctx->nr_events)
4183 0 : goto out;
4184 :
4185 0 : cpuctx = __get_cpu_context(ctx);
4186 0 : perf_ctx_lock(cpuctx, ctx);
4187 0 : ctx_sched_out(ctx, cpuctx, EVENT_TIME);
4188 0 : list_for_each_entry(event, &ctx->event_list, event_entry) {
4189 0 : enabled |= event_enable_on_exec(event, ctx);
4190 0 : event_type |= get_event_type(event);
4191 : }
4192 :
4193 : /*
4194 : * Unclone and reschedule this context if we enabled any event.
4195 : */
4196 0 : if (enabled) {
4197 0 : clone_ctx = unclone_ctx(ctx);
4198 0 : ctx_resched(cpuctx, ctx, event_type);
4199 : } else {
4200 0 : ctx_sched_in(ctx, cpuctx, EVENT_TIME, current);
4201 : }
4202 0 : perf_ctx_unlock(cpuctx, ctx);
4203 :
4204 0 : out:
4205 0 : local_irq_restore(flags);
4206 :
4207 0 : if (clone_ctx)
4208 0 : put_ctx(clone_ctx);
4209 0 : }
4210 :
4211 : struct perf_read_data {
4212 : struct perf_event *event;
4213 : bool group;
4214 : int ret;
4215 : };
4216 :
4217 0 : static int __perf_event_read_cpu(struct perf_event *event, int event_cpu)
4218 : {
4219 0 : u16 local_pkg, event_pkg;
4220 :
4221 0 : if (event->group_caps & PERF_EV_CAP_READ_ACTIVE_PKG) {
4222 0 : int local_cpu = smp_processor_id();
4223 :
4224 0 : event_pkg = topology_physical_package_id(event_cpu);
4225 0 : local_pkg = topology_physical_package_id(local_cpu);
4226 :
4227 0 : if (event_pkg == local_pkg)
4228 0 : return local_cpu;
4229 : }
4230 :
4231 : return event_cpu;
4232 : }
4233 :
4234 : /*
4235 : * Cross CPU call to read the hardware event
4236 : */
4237 0 : static void __perf_event_read(void *info)
4238 : {
4239 0 : struct perf_read_data *data = info;
4240 0 : struct perf_event *sub, *event = data->event;
4241 0 : struct perf_event_context *ctx = event->ctx;
4242 0 : struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
4243 0 : struct pmu *pmu = event->pmu;
4244 :
4245 : /*
4246 : * If this is a task context, we need to check whether it is
4247 : * the current task context of this cpu. If not it has been
4248 : * scheduled out before the smp call arrived. In that case
4249 : * event->count would have been updated to a recent sample
4250 : * when the event was scheduled out.
4251 : */
4252 0 : if (ctx->task && cpuctx->task_ctx != ctx)
4253 : return;
4254 :
4255 0 : raw_spin_lock(&ctx->lock);
4256 0 : if (ctx->is_active & EVENT_TIME) {
4257 0 : update_context_time(ctx);
4258 0 : update_cgrp_time_from_event(event);
4259 : }
4260 :
4261 0 : perf_event_update_time(event);
4262 0 : if (data->group)
4263 0 : perf_event_update_sibling_time(event);
4264 :
4265 0 : if (event->state != PERF_EVENT_STATE_ACTIVE)
4266 0 : goto unlock;
4267 :
4268 0 : if (!data->group) {
4269 0 : pmu->read(event);
4270 0 : data->ret = 0;
4271 0 : goto unlock;
4272 : }
4273 :
4274 0 : pmu->start_txn(pmu, PERF_PMU_TXN_READ);
4275 :
4276 0 : pmu->read(event);
4277 :
4278 0 : for_each_sibling_event(sub, event) {
4279 0 : if (sub->state == PERF_EVENT_STATE_ACTIVE) {
4280 : /*
4281 : * Use sibling's PMU rather than @event's since
4282 : * sibling could be on different (eg: software) PMU.
4283 : */
4284 0 : sub->pmu->read(sub);
4285 : }
4286 : }
4287 :
4288 0 : data->ret = pmu->commit_txn(pmu);
4289 :
4290 0 : unlock:
4291 0 : raw_spin_unlock(&ctx->lock);
4292 : }
4293 :
4294 0 : static inline u64 perf_event_count(struct perf_event *event)
4295 : {
4296 0 : return local64_read(&event->count) + atomic64_read(&event->child_count);
4297 : }
4298 :
4299 : /*
4300 : * NMI-safe method to read a local event, that is an event that
4301 : * is:
4302 : * - either for the current task, or for this CPU
4303 : * - does not have inherit set, for inherited task events
4304 : * will not be local and we cannot read them atomically
4305 : * - must not have a pmu::count method
4306 : */
4307 0 : int perf_event_read_local(struct perf_event *event, u64 *value,
4308 : u64 *enabled, u64 *running)
4309 : {
4310 0 : unsigned long flags;
4311 0 : int ret = 0;
4312 :
4313 : /*
4314 : * Disabling interrupts avoids all counter scheduling (context
4315 : * switches, timer based rotation and IPIs).
4316 : */
4317 0 : local_irq_save(flags);
4318 :
4319 : /*
4320 : * It must not be an event with inherit set, we cannot read
4321 : * all child counters from atomic context.
4322 : */
4323 0 : if (event->attr.inherit) {
4324 0 : ret = -EOPNOTSUPP;
4325 0 : goto out;
4326 : }
4327 :
4328 : /* If this is a per-task event, it must be for current */
4329 0 : if ((event->attach_state & PERF_ATTACH_TASK) &&
4330 0 : event->hw.target != current) {
4331 0 : ret = -EINVAL;
4332 0 : goto out;
4333 : }
4334 :
4335 : /* If this is a per-CPU event, it must be for this CPU */
4336 0 : if (!(event->attach_state & PERF_ATTACH_TASK) &&
4337 0 : event->cpu != smp_processor_id()) {
4338 0 : ret = -EINVAL;
4339 0 : goto out;
4340 : }
4341 :
4342 : /* If this is a pinned event it must be running on this CPU */
4343 0 : if (event->attr.pinned && event->oncpu != smp_processor_id()) {
4344 0 : ret = -EBUSY;
4345 0 : goto out;
4346 : }
4347 :
4348 : /*
4349 : * If the event is currently on this CPU, its either a per-task event,
4350 : * or local to this CPU. Furthermore it means its ACTIVE (otherwise
4351 : * oncpu == -1).
4352 : */
4353 0 : if (event->oncpu == smp_processor_id())
4354 0 : event->pmu->read(event);
4355 :
4356 0 : *value = local64_read(&event->count);
4357 0 : if (enabled || running) {
4358 0 : u64 now = event->shadow_ctx_time + perf_clock();
4359 0 : u64 __enabled, __running;
4360 :
4361 0 : __perf_update_times(event, now, &__enabled, &__running);
4362 0 : if (enabled)
4363 0 : *enabled = __enabled;
4364 0 : if (running)
4365 0 : *running = __running;
4366 : }
4367 0 : out:
4368 0 : local_irq_restore(flags);
4369 :
4370 0 : return ret;
4371 : }
4372 :
4373 0 : static int perf_event_read(struct perf_event *event, bool group)
4374 : {
4375 0 : enum perf_event_state state = READ_ONCE(event->state);
4376 0 : int event_cpu, ret = 0;
4377 :
4378 : /*
4379 : * If event is enabled and currently active on a CPU, update the
4380 : * value in the event structure:
4381 : */
4382 0 : again:
4383 0 : if (state == PERF_EVENT_STATE_ACTIVE) {
4384 0 : struct perf_read_data data;
4385 :
4386 : /*
4387 : * Orders the ->state and ->oncpu loads such that if we see
4388 : * ACTIVE we must also see the right ->oncpu.
4389 : *
4390 : * Matches the smp_wmb() from event_sched_in().
4391 : */
4392 0 : smp_rmb();
4393 :
4394 0 : event_cpu = READ_ONCE(event->oncpu);
4395 0 : if ((unsigned)event_cpu >= nr_cpu_ids)
4396 0 : return 0;
4397 :
4398 0 : data = (struct perf_read_data){
4399 : .event = event,
4400 : .group = group,
4401 : .ret = 0,
4402 : };
4403 :
4404 0 : preempt_disable();
4405 0 : event_cpu = __perf_event_read_cpu(event, event_cpu);
4406 :
4407 : /*
4408 : * Purposely ignore the smp_call_function_single() return
4409 : * value.
4410 : *
4411 : * If event_cpu isn't a valid CPU it means the event got
4412 : * scheduled out and that will have updated the event count.
4413 : *
4414 : * Therefore, either way, we'll have an up-to-date event count
4415 : * after this.
4416 : */
4417 0 : (void)smp_call_function_single(event_cpu, __perf_event_read, &data, 1);
4418 0 : preempt_enable();
4419 0 : ret = data.ret;
4420 :
4421 0 : } else if (state == PERF_EVENT_STATE_INACTIVE) {
4422 0 : struct perf_event_context *ctx = event->ctx;
4423 0 : unsigned long flags;
4424 :
4425 0 : raw_spin_lock_irqsave(&ctx->lock, flags);
4426 0 : state = event->state;
4427 0 : if (state != PERF_EVENT_STATE_INACTIVE) {
4428 0 : raw_spin_unlock_irqrestore(&ctx->lock, flags);
4429 0 : goto again;
4430 : }
4431 :
4432 : /*
4433 : * May read while context is not active (e.g., thread is
4434 : * blocked), in that case we cannot update context time
4435 : */
4436 0 : if (ctx->is_active & EVENT_TIME) {
4437 0 : update_context_time(ctx);
4438 0 : update_cgrp_time_from_event(event);
4439 : }
4440 :
4441 0 : perf_event_update_time(event);
4442 0 : if (group)
4443 0 : perf_event_update_sibling_time(event);
4444 0 : raw_spin_unlock_irqrestore(&ctx->lock, flags);
4445 : }
4446 :
4447 : return ret;
4448 : }
4449 :
4450 : /*
4451 : * Initialize the perf_event context in a task_struct:
4452 : */
4453 8 : static void __perf_event_init_context(struct perf_event_context *ctx)
4454 : {
4455 8 : raw_spin_lock_init(&ctx->lock);
4456 8 : mutex_init(&ctx->mutex);
4457 8 : INIT_LIST_HEAD(&ctx->active_ctx_list);
4458 8 : perf_event_groups_init(&ctx->pinned_groups);
4459 8 : perf_event_groups_init(&ctx->flexible_groups);
4460 8 : INIT_LIST_HEAD(&ctx->event_list);
4461 8 : INIT_LIST_HEAD(&ctx->pinned_active);
4462 8 : INIT_LIST_HEAD(&ctx->flexible_active);
4463 8 : refcount_set(&ctx->refcount, 1);
4464 8 : }
4465 :
4466 : static struct perf_event_context *
4467 0 : alloc_perf_context(struct pmu *pmu, struct task_struct *task)
4468 : {
4469 0 : struct perf_event_context *ctx;
4470 :
4471 0 : ctx = kzalloc(sizeof(struct perf_event_context), GFP_KERNEL);
4472 0 : if (!ctx)
4473 : return NULL;
4474 :
4475 0 : __perf_event_init_context(ctx);
4476 0 : if (task)
4477 0 : ctx->task = get_task_struct(task);
4478 0 : ctx->pmu = pmu;
4479 :
4480 0 : return ctx;
4481 : }
4482 :
4483 : static struct task_struct *
4484 0 : find_lively_task_by_vpid(pid_t vpid)
4485 : {
4486 0 : struct task_struct *task;
4487 :
4488 0 : rcu_read_lock();
4489 0 : if (!vpid)
4490 0 : task = current;
4491 : else
4492 0 : task = find_task_by_vpid(vpid);
4493 0 : if (task)
4494 0 : get_task_struct(task);
4495 0 : rcu_read_unlock();
4496 :
4497 0 : if (!task)
4498 0 : return ERR_PTR(-ESRCH);
4499 :
4500 : return task;
4501 : }
4502 :
4503 : /*
4504 : * Returns a matching context with refcount and pincount.
4505 : */
4506 : static struct perf_event_context *
4507 0 : find_get_context(struct pmu *pmu, struct task_struct *task,
4508 : struct perf_event *event)
4509 : {
4510 0 : struct perf_event_context *ctx, *clone_ctx = NULL;
4511 0 : struct perf_cpu_context *cpuctx;
4512 0 : void *task_ctx_data = NULL;
4513 0 : unsigned long flags;
4514 0 : int ctxn, err;
4515 0 : int cpu = event->cpu;
4516 :
4517 0 : if (!task) {
4518 : /* Must be root to operate on a CPU event: */
4519 0 : err = perf_allow_cpu(&event->attr);
4520 0 : if (err)
4521 0 : return ERR_PTR(err);
4522 :
4523 0 : cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
4524 0 : ctx = &cpuctx->ctx;
4525 0 : get_ctx(ctx);
4526 0 : ++ctx->pin_count;
4527 :
4528 0 : return ctx;
4529 : }
4530 :
4531 0 : err = -EINVAL;
4532 0 : ctxn = pmu->task_ctx_nr;
4533 0 : if (ctxn < 0)
4534 0 : goto errout;
4535 :
4536 0 : if (event->attach_state & PERF_ATTACH_TASK_DATA) {
4537 0 : task_ctx_data = alloc_task_ctx_data(pmu);
4538 0 : if (!task_ctx_data) {
4539 0 : err = -ENOMEM;
4540 0 : goto errout;
4541 : }
4542 : }
4543 :
4544 0 : retry:
4545 0 : ctx = perf_lock_task_context(task, ctxn, &flags);
4546 0 : if (ctx) {
4547 0 : clone_ctx = unclone_ctx(ctx);
4548 0 : ++ctx->pin_count;
4549 :
4550 0 : if (task_ctx_data && !ctx->task_ctx_data) {
4551 0 : ctx->task_ctx_data = task_ctx_data;
4552 0 : task_ctx_data = NULL;
4553 : }
4554 0 : raw_spin_unlock_irqrestore(&ctx->lock, flags);
4555 :
4556 0 : if (clone_ctx)
4557 0 : put_ctx(clone_ctx);
4558 : } else {
4559 0 : ctx = alloc_perf_context(pmu, task);
4560 0 : err = -ENOMEM;
4561 0 : if (!ctx)
4562 0 : goto errout;
4563 :
4564 0 : if (task_ctx_data) {
4565 0 : ctx->task_ctx_data = task_ctx_data;
4566 0 : task_ctx_data = NULL;
4567 : }
4568 :
4569 0 : err = 0;
4570 0 : mutex_lock(&task->perf_event_mutex);
4571 : /*
4572 : * If it has already passed perf_event_exit_task().
4573 : * we must see PF_EXITING, it takes this mutex too.
4574 : */
4575 0 : if (task->flags & PF_EXITING)
4576 : err = -ESRCH;
4577 0 : else if (task->perf_event_ctxp[ctxn])
4578 : err = -EAGAIN;
4579 : else {
4580 0 : get_ctx(ctx);
4581 0 : ++ctx->pin_count;
4582 0 : rcu_assign_pointer(task->perf_event_ctxp[ctxn], ctx);
4583 : }
4584 0 : mutex_unlock(&task->perf_event_mutex);
4585 :
4586 0 : if (unlikely(err)) {
4587 0 : put_ctx(ctx);
4588 :
4589 0 : if (err == -EAGAIN)
4590 0 : goto retry;
4591 0 : goto errout;
4592 : }
4593 : }
4594 :
4595 0 : free_task_ctx_data(pmu, task_ctx_data);
4596 0 : return ctx;
4597 :
4598 0 : errout:
4599 0 : free_task_ctx_data(pmu, task_ctx_data);
4600 0 : return ERR_PTR(err);
4601 : }
4602 :
4603 : static void perf_event_free_filter(struct perf_event *event);
4604 : static void perf_event_free_bpf_prog(struct perf_event *event);
4605 :
4606 0 : static void free_event_rcu(struct rcu_head *head)
4607 : {
4608 0 : struct perf_event *event;
4609 :
4610 0 : event = container_of(head, struct perf_event, rcu_head);
4611 0 : if (event->ns)
4612 0 : put_pid_ns(event->ns);
4613 0 : perf_event_free_filter(event);
4614 0 : kfree(event);
4615 0 : }
4616 :
4617 : static void ring_buffer_attach(struct perf_event *event,
4618 : struct perf_buffer *rb);
4619 :
4620 0 : static void detach_sb_event(struct perf_event *event)
4621 : {
4622 0 : struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
4623 :
4624 0 : raw_spin_lock(&pel->lock);
4625 0 : list_del_rcu(&event->sb_list);
4626 0 : raw_spin_unlock(&pel->lock);
4627 0 : }
4628 :
4629 0 : static bool is_sb_event(struct perf_event *event)
4630 : {
4631 0 : struct perf_event_attr *attr = &event->attr;
4632 :
4633 0 : if (event->parent)
4634 : return false;
4635 :
4636 0 : if (event->attach_state & PERF_ATTACH_TASK)
4637 : return false;
4638 :
4639 0 : if (attr->mmap || attr->mmap_data || attr->mmap2 ||
4640 : attr->comm || attr->comm_exec ||
4641 : attr->task || attr->ksymbol ||
4642 0 : attr->context_switch || attr->text_poke ||
4643 : attr->bpf_event)
4644 0 : return true;
4645 : return false;
4646 : }
4647 :
4648 0 : static void unaccount_pmu_sb_event(struct perf_event *event)
4649 : {
4650 0 : if (is_sb_event(event))
4651 0 : detach_sb_event(event);
4652 0 : }
4653 :
4654 0 : static void unaccount_event_cpu(struct perf_event *event, int cpu)
4655 : {
4656 0 : if (event->parent)
4657 : return;
4658 :
4659 0 : if (is_cgroup_event(event))
4660 0 : atomic_dec(&per_cpu(perf_cgroup_events, cpu));
4661 : }
4662 :
4663 : #ifdef CONFIG_NO_HZ_FULL
4664 : static DEFINE_SPINLOCK(nr_freq_lock);
4665 : #endif
4666 :
4667 : static void unaccount_freq_event_nohz(void)
4668 : {
4669 : #ifdef CONFIG_NO_HZ_FULL
4670 : spin_lock(&nr_freq_lock);
4671 : if (atomic_dec_and_test(&nr_freq_events))
4672 : tick_nohz_dep_clear(TICK_DEP_BIT_PERF_EVENTS);
4673 : spin_unlock(&nr_freq_lock);
4674 : #endif
4675 : }
4676 :
4677 0 : static void unaccount_freq_event(void)
4678 : {
4679 0 : if (tick_nohz_full_enabled())
4680 : unaccount_freq_event_nohz();
4681 : else
4682 0 : atomic_dec(&nr_freq_events);
4683 0 : }
4684 :
4685 0 : static void unaccount_event(struct perf_event *event)
4686 : {
4687 0 : bool dec = false;
4688 :
4689 0 : if (event->parent)
4690 : return;
4691 :
4692 0 : if (event->attach_state & (PERF_ATTACH_TASK | PERF_ATTACH_SCHED_CB))
4693 0 : dec = true;
4694 0 : if (event->attr.mmap || event->attr.mmap_data)
4695 0 : atomic_dec(&nr_mmap_events);
4696 0 : if (event->attr.build_id)
4697 0 : atomic_dec(&nr_build_id_events);
4698 0 : if (event->attr.comm)
4699 0 : atomic_dec(&nr_comm_events);
4700 0 : if (event->attr.namespaces)
4701 0 : atomic_dec(&nr_namespaces_events);
4702 0 : if (event->attr.cgroup)
4703 0 : atomic_dec(&nr_cgroup_events);
4704 0 : if (event->attr.task)
4705 0 : atomic_dec(&nr_task_events);
4706 0 : if (event->attr.freq)
4707 0 : unaccount_freq_event();
4708 0 : if (event->attr.context_switch) {
4709 0 : dec = true;
4710 0 : atomic_dec(&nr_switch_events);
4711 : }
4712 0 : if (is_cgroup_event(event))
4713 : dec = true;
4714 0 : if (has_branch_stack(event))
4715 0 : dec = true;
4716 0 : if (event->attr.ksymbol)
4717 0 : atomic_dec(&nr_ksymbol_events);
4718 0 : if (event->attr.bpf_event)
4719 0 : atomic_dec(&nr_bpf_events);
4720 0 : if (event->attr.text_poke)
4721 0 : atomic_dec(&nr_text_poke_events);
4722 :
4723 0 : if (dec) {
4724 0 : if (!atomic_add_unless(&perf_sched_count, -1, 1))
4725 0 : schedule_delayed_work(&perf_sched_work, HZ);
4726 : }
4727 :
4728 0 : unaccount_event_cpu(event, event->cpu);
4729 :
4730 0 : unaccount_pmu_sb_event(event);
4731 : }
4732 :
4733 0 : static void perf_sched_delayed(struct work_struct *work)
4734 : {
4735 0 : mutex_lock(&perf_sched_mutex);
4736 0 : if (atomic_dec_and_test(&perf_sched_count))
4737 0 : static_branch_disable(&perf_sched_events);
4738 0 : mutex_unlock(&perf_sched_mutex);
4739 0 : }
4740 :
4741 : /*
4742 : * The following implement mutual exclusion of events on "exclusive" pmus
4743 : * (PERF_PMU_CAP_EXCLUSIVE). Such pmus can only have one event scheduled
4744 : * at a time, so we disallow creating events that might conflict, namely:
4745 : *
4746 : * 1) cpu-wide events in the presence of per-task events,
4747 : * 2) per-task events in the presence of cpu-wide events,
4748 : * 3) two matching events on the same context.
4749 : *
4750 : * The former two cases are handled in the allocation path (perf_event_alloc(),
4751 : * _free_event()), the latter -- before the first perf_install_in_context().
4752 : */
4753 0 : static int exclusive_event_init(struct perf_event *event)
4754 : {
4755 0 : struct pmu *pmu = event->pmu;
4756 :
4757 0 : if (!is_exclusive_pmu(pmu))
4758 : return 0;
4759 :
4760 : /*
4761 : * Prevent co-existence of per-task and cpu-wide events on the
4762 : * same exclusive pmu.
4763 : *
4764 : * Negative pmu::exclusive_cnt means there are cpu-wide
4765 : * events on this "exclusive" pmu, positive means there are
4766 : * per-task events.
4767 : *
4768 : * Since this is called in perf_event_alloc() path, event::ctx
4769 : * doesn't exist yet; it is, however, safe to use PERF_ATTACH_TASK
4770 : * to mean "per-task event", because unlike other attach states it
4771 : * never gets cleared.
4772 : */
4773 0 : if (event->attach_state & PERF_ATTACH_TASK) {
4774 0 : if (!atomic_inc_unless_negative(&pmu->exclusive_cnt))
4775 0 : return -EBUSY;
4776 : } else {
4777 0 : if (!atomic_dec_unless_positive(&pmu->exclusive_cnt))
4778 0 : return -EBUSY;
4779 : }
4780 :
4781 : return 0;
4782 : }
4783 :
4784 0 : static void exclusive_event_destroy(struct perf_event *event)
4785 : {
4786 0 : struct pmu *pmu = event->pmu;
4787 :
4788 0 : if (!is_exclusive_pmu(pmu))
4789 : return;
4790 :
4791 : /* see comment in exclusive_event_init() */
4792 0 : if (event->attach_state & PERF_ATTACH_TASK)
4793 0 : atomic_dec(&pmu->exclusive_cnt);
4794 : else
4795 0 : atomic_inc(&pmu->exclusive_cnt);
4796 : }
4797 :
4798 0 : static bool exclusive_event_match(struct perf_event *e1, struct perf_event *e2)
4799 : {
4800 0 : if ((e1->pmu == e2->pmu) &&
4801 0 : (e1->cpu == e2->cpu ||
4802 0 : e1->cpu == -1 ||
4803 : e2->cpu == -1))
4804 : return true;
4805 : return false;
4806 : }
4807 :
4808 0 : static bool exclusive_event_installable(struct perf_event *event,
4809 : struct perf_event_context *ctx)
4810 : {
4811 0 : struct perf_event *iter_event;
4812 0 : struct pmu *pmu = event->pmu;
4813 :
4814 0 : lockdep_assert_held(&ctx->mutex);
4815 :
4816 0 : if (!is_exclusive_pmu(pmu))
4817 : return true;
4818 :
4819 0 : list_for_each_entry(iter_event, &ctx->event_list, event_entry) {
4820 0 : if (exclusive_event_match(iter_event, event))
4821 : return false;
4822 : }
4823 :
4824 : return true;
4825 : }
4826 :
4827 : static void perf_addr_filters_splice(struct perf_event *event,
4828 : struct list_head *head);
4829 :
4830 0 : static void _free_event(struct perf_event *event)
4831 : {
4832 0 : irq_work_sync(&event->pending);
4833 :
4834 0 : unaccount_event(event);
4835 :
4836 0 : security_perf_event_free(event);
4837 :
4838 0 : if (event->rb) {
4839 : /*
4840 : * Can happen when we close an event with re-directed output.
4841 : *
4842 : * Since we have a 0 refcount, perf_mmap_close() will skip
4843 : * over us; possibly making our ring_buffer_put() the last.
4844 : */
4845 0 : mutex_lock(&event->mmap_mutex);
4846 0 : ring_buffer_attach(event, NULL);
4847 0 : mutex_unlock(&event->mmap_mutex);
4848 : }
4849 :
4850 0 : if (is_cgroup_event(event))
4851 0 : perf_detach_cgroup(event);
4852 :
4853 0 : if (!event->parent) {
4854 0 : if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
4855 0 : put_callchain_buffers();
4856 : }
4857 :
4858 0 : perf_event_free_bpf_prog(event);
4859 0 : perf_addr_filters_splice(event, NULL);
4860 0 : kfree(event->addr_filter_ranges);
4861 :
4862 0 : if (event->destroy)
4863 0 : event->destroy(event);
4864 :
4865 : /*
4866 : * Must be after ->destroy(), due to uprobe_perf_close() using
4867 : * hw.target.
4868 : */
4869 0 : if (event->hw.target)
4870 0 : put_task_struct(event->hw.target);
4871 :
4872 : /*
4873 : * perf_event_free_task() relies on put_ctx() being 'last', in particular
4874 : * all task references must be cleaned up.
4875 : */
4876 0 : if (event->ctx)
4877 0 : put_ctx(event->ctx);
4878 :
4879 0 : exclusive_event_destroy(event);
4880 0 : module_put(event->pmu->module);
4881 :
4882 0 : call_rcu(&event->rcu_head, free_event_rcu);
4883 0 : }
4884 :
4885 : /*
4886 : * Used to free events which have a known refcount of 1, such as in error paths
4887 : * where the event isn't exposed yet and inherited events.
4888 : */
4889 0 : static void free_event(struct perf_event *event)
4890 : {
4891 0 : if (WARN(atomic_long_cmpxchg(&event->refcount, 1, 0) != 1,
4892 : "unexpected event refcount: %ld; ptr=%p\n",
4893 : atomic_long_read(&event->refcount), event)) {
4894 : /* leak to avoid use-after-free */
4895 : return;
4896 : }
4897 :
4898 0 : _free_event(event);
4899 : }
4900 :
4901 : /*
4902 : * Remove user event from the owner task.
4903 : */
4904 0 : static void perf_remove_from_owner(struct perf_event *event)
4905 : {
4906 0 : struct task_struct *owner;
4907 :
4908 0 : rcu_read_lock();
4909 : /*
4910 : * Matches the smp_store_release() in perf_event_exit_task(). If we
4911 : * observe !owner it means the list deletion is complete and we can
4912 : * indeed free this event, otherwise we need to serialize on
4913 : * owner->perf_event_mutex.
4914 : */
4915 0 : owner = READ_ONCE(event->owner);
4916 0 : if (owner) {
4917 : /*
4918 : * Since delayed_put_task_struct() also drops the last
4919 : * task reference we can safely take a new reference
4920 : * while holding the rcu_read_lock().
4921 : */
4922 0 : get_task_struct(owner);
4923 : }
4924 0 : rcu_read_unlock();
4925 :
4926 0 : if (owner) {
4927 : /*
4928 : * If we're here through perf_event_exit_task() we're already
4929 : * holding ctx->mutex which would be an inversion wrt. the
4930 : * normal lock order.
4931 : *
4932 : * However we can safely take this lock because its the child
4933 : * ctx->mutex.
4934 : */
4935 0 : mutex_lock_nested(&owner->perf_event_mutex, SINGLE_DEPTH_NESTING);
4936 :
4937 : /*
4938 : * We have to re-check the event->owner field, if it is cleared
4939 : * we raced with perf_event_exit_task(), acquiring the mutex
4940 : * ensured they're done, and we can proceed with freeing the
4941 : * event.
4942 : */
4943 0 : if (event->owner) {
4944 0 : list_del_init(&event->owner_entry);
4945 0 : smp_store_release(&event->owner, NULL);
4946 : }
4947 0 : mutex_unlock(&owner->perf_event_mutex);
4948 0 : put_task_struct(owner);
4949 : }
4950 0 : }
4951 :
4952 0 : static void put_event(struct perf_event *event)
4953 : {
4954 0 : if (!atomic_long_dec_and_test(&event->refcount))
4955 : return;
4956 :
4957 0 : _free_event(event);
4958 : }
4959 :
4960 : /*
4961 : * Kill an event dead; while event:refcount will preserve the event
4962 : * object, it will not preserve its functionality. Once the last 'user'
4963 : * gives up the object, we'll destroy the thing.
4964 : */
4965 0 : int perf_event_release_kernel(struct perf_event *event)
4966 : {
4967 0 : struct perf_event_context *ctx = event->ctx;
4968 0 : struct perf_event *child, *tmp;
4969 0 : LIST_HEAD(free_list);
4970 :
4971 : /*
4972 : * If we got here through err_file: fput(event_file); we will not have
4973 : * attached to a context yet.
4974 : */
4975 0 : if (!ctx) {
4976 0 : WARN_ON_ONCE(event->attach_state &
4977 : (PERF_ATTACH_CONTEXT|PERF_ATTACH_GROUP));
4978 0 : goto no_ctx;
4979 : }
4980 :
4981 0 : if (!is_kernel_event(event))
4982 0 : perf_remove_from_owner(event);
4983 :
4984 0 : ctx = perf_event_ctx_lock(event);
4985 0 : WARN_ON_ONCE(ctx->parent_ctx);
4986 0 : perf_remove_from_context(event, DETACH_GROUP);
4987 :
4988 0 : raw_spin_lock_irq(&ctx->lock);
4989 : /*
4990 : * Mark this event as STATE_DEAD, there is no external reference to it
4991 : * anymore.
4992 : *
4993 : * Anybody acquiring event->child_mutex after the below loop _must_
4994 : * also see this, most importantly inherit_event() which will avoid
4995 : * placing more children on the list.
4996 : *
4997 : * Thus this guarantees that we will in fact observe and kill _ALL_
4998 : * child events.
4999 : */
5000 0 : event->state = PERF_EVENT_STATE_DEAD;
5001 0 : raw_spin_unlock_irq(&ctx->lock);
5002 :
5003 0 : perf_event_ctx_unlock(event, ctx);
5004 :
5005 0 : again:
5006 0 : mutex_lock(&event->child_mutex);
5007 0 : list_for_each_entry(child, &event->child_list, child_list) {
5008 :
5009 : /*
5010 : * Cannot change, child events are not migrated, see the
5011 : * comment with perf_event_ctx_lock_nested().
5012 : */
5013 0 : ctx = READ_ONCE(child->ctx);
5014 : /*
5015 : * Since child_mutex nests inside ctx::mutex, we must jump
5016 : * through hoops. We start by grabbing a reference on the ctx.
5017 : *
5018 : * Since the event cannot get freed while we hold the
5019 : * child_mutex, the context must also exist and have a !0
5020 : * reference count.
5021 : */
5022 0 : get_ctx(ctx);
5023 :
5024 : /*
5025 : * Now that we have a ctx ref, we can drop child_mutex, and
5026 : * acquire ctx::mutex without fear of it going away. Then we
5027 : * can re-acquire child_mutex.
5028 : */
5029 0 : mutex_unlock(&event->child_mutex);
5030 0 : mutex_lock(&ctx->mutex);
5031 0 : mutex_lock(&event->child_mutex);
5032 :
5033 : /*
5034 : * Now that we hold ctx::mutex and child_mutex, revalidate our
5035 : * state, if child is still the first entry, it didn't get freed
5036 : * and we can continue doing so.
5037 : */
5038 0 : tmp = list_first_entry_or_null(&event->child_list,
5039 : struct perf_event, child_list);
5040 0 : if (tmp == child) {
5041 0 : perf_remove_from_context(child, DETACH_GROUP);
5042 0 : list_move(&child->child_list, &free_list);
5043 : /*
5044 : * This matches the refcount bump in inherit_event();
5045 : * this can't be the last reference.
5046 : */
5047 0 : put_event(event);
5048 : }
5049 :
5050 0 : mutex_unlock(&event->child_mutex);
5051 0 : mutex_unlock(&ctx->mutex);
5052 0 : put_ctx(ctx);
5053 0 : goto again;
5054 : }
5055 0 : mutex_unlock(&event->child_mutex);
5056 :
5057 0 : list_for_each_entry_safe(child, tmp, &free_list, child_list) {
5058 0 : void *var = &child->ctx->refcount;
5059 :
5060 0 : list_del(&child->child_list);
5061 0 : free_event(child);
5062 :
5063 : /*
5064 : * Wake any perf_event_free_task() waiting for this event to be
5065 : * freed.
5066 : */
5067 0 : smp_mb(); /* pairs with wait_var_event() */
5068 0 : wake_up_var(var);
5069 : }
5070 :
5071 0 : no_ctx:
5072 0 : put_event(event); /* Must be the 'last' reference */
5073 0 : return 0;
5074 : }
5075 : EXPORT_SYMBOL_GPL(perf_event_release_kernel);
5076 :
5077 : /*
5078 : * Called when the last reference to the file is gone.
5079 : */
5080 0 : static int perf_release(struct inode *inode, struct file *file)
5081 : {
5082 0 : perf_event_release_kernel(file->private_data);
5083 0 : return 0;
5084 : }
5085 :
5086 0 : static u64 __perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
5087 : {
5088 0 : struct perf_event *child;
5089 0 : u64 total = 0;
5090 :
5091 0 : *enabled = 0;
5092 0 : *running = 0;
5093 :
5094 0 : mutex_lock(&event->child_mutex);
5095 :
5096 0 : (void)perf_event_read(event, false);
5097 0 : total += perf_event_count(event);
5098 :
5099 0 : *enabled += event->total_time_enabled +
5100 0 : atomic64_read(&event->child_total_time_enabled);
5101 0 : *running += event->total_time_running +
5102 0 : atomic64_read(&event->child_total_time_running);
5103 :
5104 0 : list_for_each_entry(child, &event->child_list, child_list) {
5105 0 : (void)perf_event_read(child, false);
5106 0 : total += perf_event_count(child);
5107 0 : *enabled += child->total_time_enabled;
5108 0 : *running += child->total_time_running;
5109 : }
5110 0 : mutex_unlock(&event->child_mutex);
5111 :
5112 0 : return total;
5113 : }
5114 :
5115 0 : u64 perf_event_read_value(struct perf_event *event, u64 *enabled, u64 *running)
5116 : {
5117 0 : struct perf_event_context *ctx;
5118 0 : u64 count;
5119 :
5120 0 : ctx = perf_event_ctx_lock(event);
5121 0 : count = __perf_event_read_value(event, enabled, running);
5122 0 : perf_event_ctx_unlock(event, ctx);
5123 :
5124 0 : return count;
5125 : }
5126 : EXPORT_SYMBOL_GPL(perf_event_read_value);
5127 :
5128 0 : static int __perf_read_group_add(struct perf_event *leader,
5129 : u64 read_format, u64 *values)
5130 : {
5131 0 : struct perf_event_context *ctx = leader->ctx;
5132 0 : struct perf_event *sub;
5133 0 : unsigned long flags;
5134 0 : int n = 1; /* skip @nr */
5135 0 : int ret;
5136 :
5137 0 : ret = perf_event_read(leader, true);
5138 0 : if (ret)
5139 : return ret;
5140 :
5141 0 : raw_spin_lock_irqsave(&ctx->lock, flags);
5142 :
5143 : /*
5144 : * Since we co-schedule groups, {enabled,running} times of siblings
5145 : * will be identical to those of the leader, so we only publish one
5146 : * set.
5147 : */
5148 0 : if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
5149 0 : values[n++] += leader->total_time_enabled +
5150 0 : atomic64_read(&leader->child_total_time_enabled);
5151 : }
5152 :
5153 0 : if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
5154 0 : values[n++] += leader->total_time_running +
5155 0 : atomic64_read(&leader->child_total_time_running);
5156 : }
5157 :
5158 : /*
5159 : * Write {count,id} tuples for every sibling.
5160 : */
5161 0 : values[n++] += perf_event_count(leader);
5162 0 : if (read_format & PERF_FORMAT_ID)
5163 0 : values[n++] = primary_event_id(leader);
5164 :
5165 0 : for_each_sibling_event(sub, leader) {
5166 0 : values[n++] += perf_event_count(sub);
5167 0 : if (read_format & PERF_FORMAT_ID)
5168 0 : values[n++] = primary_event_id(sub);
5169 : }
5170 :
5171 0 : raw_spin_unlock_irqrestore(&ctx->lock, flags);
5172 0 : return 0;
5173 : }
5174 :
5175 0 : static int perf_read_group(struct perf_event *event,
5176 : u64 read_format, char __user *buf)
5177 : {
5178 0 : struct perf_event *leader = event->group_leader, *child;
5179 0 : struct perf_event_context *ctx = leader->ctx;
5180 0 : int ret;
5181 0 : u64 *values;
5182 :
5183 0 : lockdep_assert_held(&ctx->mutex);
5184 :
5185 0 : values = kzalloc(event->read_size, GFP_KERNEL);
5186 0 : if (!values)
5187 : return -ENOMEM;
5188 :
5189 0 : values[0] = 1 + leader->nr_siblings;
5190 :
5191 : /*
5192 : * By locking the child_mutex of the leader we effectively
5193 : * lock the child list of all siblings.. XXX explain how.
5194 : */
5195 0 : mutex_lock(&leader->child_mutex);
5196 :
5197 0 : ret = __perf_read_group_add(leader, read_format, values);
5198 0 : if (ret)
5199 0 : goto unlock;
5200 :
5201 0 : list_for_each_entry(child, &leader->child_list, child_list) {
5202 0 : ret = __perf_read_group_add(child, read_format, values);
5203 0 : if (ret)
5204 0 : goto unlock;
5205 : }
5206 :
5207 0 : mutex_unlock(&leader->child_mutex);
5208 :
5209 0 : ret = event->read_size;
5210 0 : if (copy_to_user(buf, values, event->read_size))
5211 0 : ret = -EFAULT;
5212 0 : goto out;
5213 :
5214 0 : unlock:
5215 0 : mutex_unlock(&leader->child_mutex);
5216 0 : out:
5217 0 : kfree(values);
5218 0 : return ret;
5219 : }
5220 :
5221 0 : static int perf_read_one(struct perf_event *event,
5222 : u64 read_format, char __user *buf)
5223 : {
5224 0 : u64 enabled, running;
5225 0 : u64 values[4];
5226 0 : int n = 0;
5227 :
5228 0 : values[n++] = __perf_event_read_value(event, &enabled, &running);
5229 0 : if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
5230 0 : values[n++] = enabled;
5231 0 : if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
5232 0 : values[n++] = running;
5233 0 : if (read_format & PERF_FORMAT_ID)
5234 0 : values[n++] = primary_event_id(event);
5235 :
5236 0 : if (copy_to_user(buf, values, n * sizeof(u64)))
5237 : return -EFAULT;
5238 :
5239 0 : return n * sizeof(u64);
5240 : }
5241 :
5242 0 : static bool is_event_hup(struct perf_event *event)
5243 : {
5244 0 : bool no_children;
5245 :
5246 0 : if (event->state > PERF_EVENT_STATE_EXIT)
5247 : return false;
5248 :
5249 0 : mutex_lock(&event->child_mutex);
5250 0 : no_children = list_empty(&event->child_list);
5251 0 : mutex_unlock(&event->child_mutex);
5252 0 : return no_children;
5253 : }
5254 :
5255 : /*
5256 : * Read the performance event - simple non blocking version for now
5257 : */
5258 : static ssize_t
5259 0 : __perf_read(struct perf_event *event, char __user *buf, size_t count)
5260 : {
5261 0 : u64 read_format = event->attr.read_format;
5262 0 : int ret;
5263 :
5264 : /*
5265 : * Return end-of-file for a read on an event that is in
5266 : * error state (i.e. because it was pinned but it couldn't be
5267 : * scheduled on to the CPU at some point).
5268 : */
5269 0 : if (event->state == PERF_EVENT_STATE_ERROR)
5270 : return 0;
5271 :
5272 0 : if (count < event->read_size)
5273 : return -ENOSPC;
5274 :
5275 0 : WARN_ON_ONCE(event->ctx->parent_ctx);
5276 0 : if (read_format & PERF_FORMAT_GROUP)
5277 0 : ret = perf_read_group(event, read_format, buf);
5278 : else
5279 0 : ret = perf_read_one(event, read_format, buf);
5280 :
5281 0 : return ret;
5282 : }
5283 :
5284 : static ssize_t
5285 0 : perf_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
5286 : {
5287 0 : struct perf_event *event = file->private_data;
5288 0 : struct perf_event_context *ctx;
5289 0 : int ret;
5290 :
5291 0 : ret = security_perf_event_read(event);
5292 0 : if (ret)
5293 0 : return ret;
5294 :
5295 0 : ctx = perf_event_ctx_lock(event);
5296 0 : ret = __perf_read(event, buf, count);
5297 0 : perf_event_ctx_unlock(event, ctx);
5298 :
5299 0 : return ret;
5300 : }
5301 :
5302 0 : static __poll_t perf_poll(struct file *file, poll_table *wait)
5303 : {
5304 0 : struct perf_event *event = file->private_data;
5305 0 : struct perf_buffer *rb;
5306 0 : __poll_t events = EPOLLHUP;
5307 :
5308 0 : poll_wait(file, &event->waitq, wait);
5309 :
5310 0 : if (is_event_hup(event))
5311 : return events;
5312 :
5313 : /*
5314 : * Pin the event->rb by taking event->mmap_mutex; otherwise
5315 : * perf_event_set_output() can swizzle our rb and make us miss wakeups.
5316 : */
5317 0 : mutex_lock(&event->mmap_mutex);
5318 0 : rb = event->rb;
5319 0 : if (rb)
5320 0 : events = atomic_xchg(&rb->poll, 0);
5321 0 : mutex_unlock(&event->mmap_mutex);
5322 0 : return events;
5323 : }
5324 :
5325 0 : static void _perf_event_reset(struct perf_event *event)
5326 : {
5327 0 : (void)perf_event_read(event, false);
5328 0 : local64_set(&event->count, 0);
5329 0 : perf_event_update_userpage(event);
5330 0 : }
5331 :
5332 : /* Assume it's not an event with inherit set. */
5333 0 : u64 perf_event_pause(struct perf_event *event, bool reset)
5334 : {
5335 0 : struct perf_event_context *ctx;
5336 0 : u64 count;
5337 :
5338 0 : ctx = perf_event_ctx_lock(event);
5339 0 : WARN_ON_ONCE(event->attr.inherit);
5340 0 : _perf_event_disable(event);
5341 0 : count = local64_read(&event->count);
5342 0 : if (reset)
5343 0 : local64_set(&event->count, 0);
5344 0 : perf_event_ctx_unlock(event, ctx);
5345 :
5346 0 : return count;
5347 : }
5348 : EXPORT_SYMBOL_GPL(perf_event_pause);
5349 :
5350 : /*
5351 : * Holding the top-level event's child_mutex means that any
5352 : * descendant process that has inherited this event will block
5353 : * in perf_event_exit_event() if it goes to exit, thus satisfying the
5354 : * task existence requirements of perf_event_enable/disable.
5355 : */
5356 0 : static void perf_event_for_each_child(struct perf_event *event,
5357 : void (*func)(struct perf_event *))
5358 : {
5359 0 : struct perf_event *child;
5360 :
5361 0 : WARN_ON_ONCE(event->ctx->parent_ctx);
5362 :
5363 0 : mutex_lock(&event->child_mutex);
5364 0 : func(event);
5365 0 : list_for_each_entry(child, &event->child_list, child_list)
5366 0 : func(child);
5367 0 : mutex_unlock(&event->child_mutex);
5368 0 : }
5369 :
5370 0 : static void perf_event_for_each(struct perf_event *event,
5371 : void (*func)(struct perf_event *))
5372 : {
5373 0 : struct perf_event_context *ctx = event->ctx;
5374 0 : struct perf_event *sibling;
5375 :
5376 0 : lockdep_assert_held(&ctx->mutex);
5377 :
5378 0 : event = event->group_leader;
5379 :
5380 0 : perf_event_for_each_child(event, func);
5381 0 : for_each_sibling_event(sibling, event)
5382 0 : perf_event_for_each_child(sibling, func);
5383 0 : }
5384 :
5385 0 : static void __perf_event_period(struct perf_event *event,
5386 : struct perf_cpu_context *cpuctx,
5387 : struct perf_event_context *ctx,
5388 : void *info)
5389 : {
5390 0 : u64 value = *((u64 *)info);
5391 0 : bool active;
5392 :
5393 0 : if (event->attr.freq) {
5394 0 : event->attr.sample_freq = value;
5395 : } else {
5396 0 : event->attr.sample_period = value;
5397 0 : event->hw.sample_period = value;
5398 : }
5399 :
5400 0 : active = (event->state == PERF_EVENT_STATE_ACTIVE);
5401 0 : if (active) {
5402 0 : perf_pmu_disable(ctx->pmu);
5403 : /*
5404 : * We could be throttled; unthrottle now to avoid the tick
5405 : * trying to unthrottle while we already re-started the event.
5406 : */
5407 0 : if (event->hw.interrupts == MAX_INTERRUPTS) {
5408 0 : event->hw.interrupts = 0;
5409 0 : perf_log_throttle(event, 1);
5410 : }
5411 0 : event->pmu->stop(event, PERF_EF_UPDATE);
5412 : }
5413 :
5414 0 : local64_set(&event->hw.period_left, 0);
5415 :
5416 0 : if (active) {
5417 0 : event->pmu->start(event, PERF_EF_RELOAD);
5418 0 : perf_pmu_enable(ctx->pmu);
5419 : }
5420 0 : }
5421 :
5422 0 : static int perf_event_check_period(struct perf_event *event, u64 value)
5423 : {
5424 0 : return event->pmu->check_period(event, value);
5425 : }
5426 :
5427 0 : static int _perf_event_period(struct perf_event *event, u64 value)
5428 : {
5429 0 : if (!is_sampling_event(event))
5430 : return -EINVAL;
5431 :
5432 0 : if (!value)
5433 : return -EINVAL;
5434 :
5435 0 : if (event->attr.freq && value > sysctl_perf_event_sample_rate)
5436 : return -EINVAL;
5437 :
5438 0 : if (perf_event_check_period(event, value))
5439 : return -EINVAL;
5440 :
5441 0 : if (!event->attr.freq && (value & (1ULL << 63)))
5442 : return -EINVAL;
5443 :
5444 0 : event_function_call(event, __perf_event_period, &value);
5445 :
5446 0 : return 0;
5447 : }
5448 :
5449 0 : int perf_event_period(struct perf_event *event, u64 value)
5450 : {
5451 0 : struct perf_event_context *ctx;
5452 0 : int ret;
5453 :
5454 0 : ctx = perf_event_ctx_lock(event);
5455 0 : ret = _perf_event_period(event, value);
5456 0 : perf_event_ctx_unlock(event, ctx);
5457 :
5458 0 : return ret;
5459 : }
5460 : EXPORT_SYMBOL_GPL(perf_event_period);
5461 :
5462 : static const struct file_operations perf_fops;
5463 :
5464 0 : static inline int perf_fget_light(int fd, struct fd *p)
5465 : {
5466 0 : struct fd f = fdget(fd);
5467 0 : if (!f.file)
5468 : return -EBADF;
5469 :
5470 0 : if (f.file->f_op != &perf_fops) {
5471 0 : fdput(f);
5472 0 : return -EBADF;
5473 : }
5474 0 : *p = f;
5475 0 : return 0;
5476 : }
5477 :
5478 : static int perf_event_set_output(struct perf_event *event,
5479 : struct perf_event *output_event);
5480 : static int perf_event_set_filter(struct perf_event *event, void __user *arg);
5481 : static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd);
5482 : static int perf_copy_attr(struct perf_event_attr __user *uattr,
5483 : struct perf_event_attr *attr);
5484 :
5485 0 : static long _perf_ioctl(struct perf_event *event, unsigned int cmd, unsigned long arg)
5486 : {
5487 0 : void (*func)(struct perf_event *);
5488 0 : u32 flags = arg;
5489 :
5490 0 : switch (cmd) {
5491 : case PERF_EVENT_IOC_ENABLE:
5492 : func = _perf_event_enable;
5493 : break;
5494 0 : case PERF_EVENT_IOC_DISABLE:
5495 0 : func = _perf_event_disable;
5496 0 : break;
5497 0 : case PERF_EVENT_IOC_RESET:
5498 0 : func = _perf_event_reset;
5499 0 : break;
5500 :
5501 0 : case PERF_EVENT_IOC_REFRESH:
5502 0 : return _perf_event_refresh(event, arg);
5503 :
5504 0 : case PERF_EVENT_IOC_PERIOD:
5505 : {
5506 0 : u64 value;
5507 :
5508 0 : if (copy_from_user(&value, (u64 __user *)arg, sizeof(value)))
5509 : return -EFAULT;
5510 :
5511 0 : return _perf_event_period(event, value);
5512 : }
5513 : case PERF_EVENT_IOC_ID:
5514 : {
5515 0 : u64 id = primary_event_id(event);
5516 :
5517 0 : if (copy_to_user((void __user *)arg, &id, sizeof(id)))
5518 0 : return -EFAULT;
5519 : return 0;
5520 : }
5521 :
5522 0 : case PERF_EVENT_IOC_SET_OUTPUT:
5523 : {
5524 0 : int ret;
5525 0 : if (arg != -1) {
5526 0 : struct perf_event *output_event;
5527 0 : struct fd output;
5528 0 : ret = perf_fget_light(arg, &output);
5529 0 : if (ret)
5530 0 : return ret;
5531 0 : output_event = output.file->private_data;
5532 0 : ret = perf_event_set_output(event, output_event);
5533 0 : fdput(output);
5534 : } else {
5535 0 : ret = perf_event_set_output(event, NULL);
5536 : }
5537 0 : return ret;
5538 : }
5539 :
5540 0 : case PERF_EVENT_IOC_SET_FILTER:
5541 0 : return perf_event_set_filter(event, (void __user *)arg);
5542 :
5543 0 : case PERF_EVENT_IOC_SET_BPF:
5544 0 : return perf_event_set_bpf_prog(event, arg);
5545 :
5546 : case PERF_EVENT_IOC_PAUSE_OUTPUT: {
5547 0 : struct perf_buffer *rb;
5548 :
5549 0 : rcu_read_lock();
5550 0 : rb = rcu_dereference(event->rb);
5551 0 : if (!rb || !rb->nr_pages) {
5552 0 : rcu_read_unlock();
5553 0 : return -EINVAL;
5554 : }
5555 0 : rb_toggle_paused(rb, !!arg);
5556 0 : rcu_read_unlock();
5557 0 : return 0;
5558 : }
5559 :
5560 0 : case PERF_EVENT_IOC_QUERY_BPF:
5561 0 : return perf_event_query_prog_array(event, (void __user *)arg);
5562 :
5563 0 : case PERF_EVENT_IOC_MODIFY_ATTRIBUTES: {
5564 0 : struct perf_event_attr new_attr;
5565 0 : int err = perf_copy_attr((struct perf_event_attr __user *)arg,
5566 : &new_attr);
5567 :
5568 0 : if (err)
5569 0 : return err;
5570 :
5571 0 : return perf_event_modify_attr(event, &new_attr);
5572 : }
5573 : default:
5574 : return -ENOTTY;
5575 : }
5576 :
5577 0 : if (flags & PERF_IOC_FLAG_GROUP)
5578 0 : perf_event_for_each(event, func);
5579 : else
5580 0 : perf_event_for_each_child(event, func);
5581 :
5582 : return 0;
5583 : }
5584 :
5585 0 : static long perf_ioctl(struct file *file, unsigned int cmd, unsigned long arg)
5586 : {
5587 0 : struct perf_event *event = file->private_data;
5588 0 : struct perf_event_context *ctx;
5589 0 : long ret;
5590 :
5591 : /* Treat ioctl like writes as it is likely a mutating operation. */
5592 0 : ret = security_perf_event_write(event);
5593 0 : if (ret)
5594 : return ret;
5595 :
5596 0 : ctx = perf_event_ctx_lock(event);
5597 0 : ret = _perf_ioctl(event, cmd, arg);
5598 0 : perf_event_ctx_unlock(event, ctx);
5599 :
5600 0 : return ret;
5601 : }
5602 :
5603 : #ifdef CONFIG_COMPAT
5604 0 : static long perf_compat_ioctl(struct file *file, unsigned int cmd,
5605 : unsigned long arg)
5606 : {
5607 0 : switch (_IOC_NR(cmd)) {
5608 0 : case _IOC_NR(PERF_EVENT_IOC_SET_FILTER):
5609 : case _IOC_NR(PERF_EVENT_IOC_ID):
5610 : case _IOC_NR(PERF_EVENT_IOC_QUERY_BPF):
5611 : case _IOC_NR(PERF_EVENT_IOC_MODIFY_ATTRIBUTES):
5612 : /* Fix up pointer size (usually 4 -> 8 in 32-on-64-bit case */
5613 0 : if (_IOC_SIZE(cmd) == sizeof(compat_uptr_t)) {
5614 0 : cmd &= ~IOCSIZE_MASK;
5615 0 : cmd |= sizeof(void *) << IOCSIZE_SHIFT;
5616 : }
5617 : break;
5618 : }
5619 0 : return perf_ioctl(file, cmd, arg);
5620 : }
5621 : #else
5622 : # define perf_compat_ioctl NULL
5623 : #endif
5624 :
5625 0 : int perf_event_task_enable(void)
5626 : {
5627 0 : struct perf_event_context *ctx;
5628 0 : struct perf_event *event;
5629 :
5630 0 : mutex_lock(¤t->perf_event_mutex);
5631 0 : list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5632 0 : ctx = perf_event_ctx_lock(event);
5633 0 : perf_event_for_each_child(event, _perf_event_enable);
5634 0 : perf_event_ctx_unlock(event, ctx);
5635 : }
5636 0 : mutex_unlock(¤t->perf_event_mutex);
5637 :
5638 0 : return 0;
5639 : }
5640 :
5641 0 : int perf_event_task_disable(void)
5642 : {
5643 0 : struct perf_event_context *ctx;
5644 0 : struct perf_event *event;
5645 :
5646 0 : mutex_lock(¤t->perf_event_mutex);
5647 0 : list_for_each_entry(event, ¤t->perf_event_list, owner_entry) {
5648 0 : ctx = perf_event_ctx_lock(event);
5649 0 : perf_event_for_each_child(event, _perf_event_disable);
5650 0 : perf_event_ctx_unlock(event, ctx);
5651 : }
5652 0 : mutex_unlock(¤t->perf_event_mutex);
5653 :
5654 0 : return 0;
5655 : }
5656 :
5657 0 : static int perf_event_index(struct perf_event *event)
5658 : {
5659 0 : if (event->hw.state & PERF_HES_STOPPED)
5660 : return 0;
5661 :
5662 0 : if (event->state != PERF_EVENT_STATE_ACTIVE)
5663 : return 0;
5664 :
5665 0 : return event->pmu->event_idx(event);
5666 : }
5667 :
5668 0 : static void calc_timer_values(struct perf_event *event,
5669 : u64 *now,
5670 : u64 *enabled,
5671 : u64 *running)
5672 : {
5673 0 : u64 ctx_time;
5674 :
5675 0 : *now = perf_clock();
5676 0 : ctx_time = event->shadow_ctx_time + *now;
5677 0 : __perf_update_times(event, ctx_time, enabled, running);
5678 0 : }
5679 :
5680 0 : static void perf_event_init_userpage(struct perf_event *event)
5681 : {
5682 0 : struct perf_event_mmap_page *userpg;
5683 0 : struct perf_buffer *rb;
5684 :
5685 0 : rcu_read_lock();
5686 0 : rb = rcu_dereference(event->rb);
5687 0 : if (!rb)
5688 0 : goto unlock;
5689 :
5690 0 : userpg = rb->user_page;
5691 :
5692 : /* Allow new userspace to detect that bit 0 is deprecated */
5693 0 : userpg->cap_bit0_is_deprecated = 1;
5694 0 : userpg->size = offsetof(struct perf_event_mmap_page, __reserved);
5695 0 : userpg->data_offset = PAGE_SIZE;
5696 0 : userpg->data_size = perf_data_size(rb);
5697 :
5698 0 : unlock:
5699 0 : rcu_read_unlock();
5700 0 : }
5701 :
5702 0 : void __weak arch_perf_update_userpage(
5703 : struct perf_event *event, struct perf_event_mmap_page *userpg, u64 now)
5704 : {
5705 0 : }
5706 :
5707 : /*
5708 : * Callers need to ensure there can be no nesting of this function, otherwise
5709 : * the seqlock logic goes bad. We can not serialize this because the arch
5710 : * code calls this from NMI context.
5711 : */
5712 0 : void perf_event_update_userpage(struct perf_event *event)
5713 : {
5714 0 : struct perf_event_mmap_page *userpg;
5715 0 : struct perf_buffer *rb;
5716 0 : u64 enabled, running, now;
5717 :
5718 0 : rcu_read_lock();
5719 0 : rb = rcu_dereference(event->rb);
5720 0 : if (!rb)
5721 0 : goto unlock;
5722 :
5723 : /*
5724 : * compute total_time_enabled, total_time_running
5725 : * based on snapshot values taken when the event
5726 : * was last scheduled in.
5727 : *
5728 : * we cannot simply called update_context_time()
5729 : * because of locking issue as we can be called in
5730 : * NMI context
5731 : */
5732 0 : calc_timer_values(event, &now, &enabled, &running);
5733 :
5734 0 : userpg = rb->user_page;
5735 : /*
5736 : * Disable preemption to guarantee consistent time stamps are stored to
5737 : * the user page.
5738 : */
5739 0 : preempt_disable();
5740 0 : ++userpg->lock;
5741 0 : barrier();
5742 0 : userpg->index = perf_event_index(event);
5743 0 : userpg->offset = perf_event_count(event);
5744 0 : if (userpg->index)
5745 0 : userpg->offset -= local64_read(&event->hw.prev_count);
5746 :
5747 0 : userpg->time_enabled = enabled +
5748 0 : atomic64_read(&event->child_total_time_enabled);
5749 :
5750 0 : userpg->time_running = running +
5751 0 : atomic64_read(&event->child_total_time_running);
5752 :
5753 0 : arch_perf_update_userpage(event, userpg, now);
5754 :
5755 0 : barrier();
5756 0 : ++userpg->lock;
5757 0 : preempt_enable();
5758 0 : unlock:
5759 0 : rcu_read_unlock();
5760 0 : }
5761 : EXPORT_SYMBOL_GPL(perf_event_update_userpage);
5762 :
5763 0 : static vm_fault_t perf_mmap_fault(struct vm_fault *vmf)
5764 : {
5765 0 : struct perf_event *event = vmf->vma->vm_file->private_data;
5766 0 : struct perf_buffer *rb;
5767 0 : vm_fault_t ret = VM_FAULT_SIGBUS;
5768 :
5769 0 : if (vmf->flags & FAULT_FLAG_MKWRITE) {
5770 0 : if (vmf->pgoff == 0)
5771 0 : ret = 0;
5772 0 : return ret;
5773 : }
5774 :
5775 0 : rcu_read_lock();
5776 0 : rb = rcu_dereference(event->rb);
5777 0 : if (!rb)
5778 0 : goto unlock;
5779 :
5780 0 : if (vmf->pgoff && (vmf->flags & FAULT_FLAG_WRITE))
5781 0 : goto unlock;
5782 :
5783 0 : vmf->page = perf_mmap_to_page(rb, vmf->pgoff);
5784 0 : if (!vmf->page)
5785 0 : goto unlock;
5786 :
5787 0 : get_page(vmf->page);
5788 0 : vmf->page->mapping = vmf->vma->vm_file->f_mapping;
5789 0 : vmf->page->index = vmf->pgoff;
5790 :
5791 0 : ret = 0;
5792 0 : unlock:
5793 0 : rcu_read_unlock();
5794 :
5795 0 : return ret;
5796 : }
5797 :
5798 0 : static void ring_buffer_attach(struct perf_event *event,
5799 : struct perf_buffer *rb)
5800 : {
5801 0 : struct perf_buffer *old_rb = NULL;
5802 0 : unsigned long flags;
5803 :
5804 0 : if (event->rb) {
5805 : /*
5806 : * Should be impossible, we set this when removing
5807 : * event->rb_entry and wait/clear when adding event->rb_entry.
5808 : */
5809 0 : WARN_ON_ONCE(event->rcu_pending);
5810 :
5811 0 : old_rb = event->rb;
5812 0 : spin_lock_irqsave(&old_rb->event_lock, flags);
5813 0 : list_del_rcu(&event->rb_entry);
5814 0 : spin_unlock_irqrestore(&old_rb->event_lock, flags);
5815 :
5816 0 : event->rcu_batches = get_state_synchronize_rcu();
5817 0 : event->rcu_pending = 1;
5818 : }
5819 :
5820 0 : if (rb) {
5821 0 : if (event->rcu_pending) {
5822 0 : cond_synchronize_rcu(event->rcu_batches);
5823 0 : event->rcu_pending = 0;
5824 : }
5825 :
5826 0 : spin_lock_irqsave(&rb->event_lock, flags);
5827 0 : list_add_rcu(&event->rb_entry, &rb->event_list);
5828 0 : spin_unlock_irqrestore(&rb->event_lock, flags);
5829 : }
5830 :
5831 : /*
5832 : * Avoid racing with perf_mmap_close(AUX): stop the event
5833 : * before swizzling the event::rb pointer; if it's getting
5834 : * unmapped, its aux_mmap_count will be 0 and it won't
5835 : * restart. See the comment in __perf_pmu_output_stop().
5836 : *
5837 : * Data will inevitably be lost when set_output is done in
5838 : * mid-air, but then again, whoever does it like this is
5839 : * not in for the data anyway.
5840 : */
5841 0 : if (has_aux(event))
5842 0 : perf_event_stop(event, 0);
5843 :
5844 0 : rcu_assign_pointer(event->rb, rb);
5845 :
5846 0 : if (old_rb) {
5847 0 : ring_buffer_put(old_rb);
5848 : /*
5849 : * Since we detached before setting the new rb, so that we
5850 : * could attach the new rb, we could have missed a wakeup.
5851 : * Provide it now.
5852 : */
5853 0 : wake_up_all(&event->waitq);
5854 : }
5855 0 : }
5856 :
5857 0 : static void ring_buffer_wakeup(struct perf_event *event)
5858 : {
5859 0 : struct perf_buffer *rb;
5860 :
5861 0 : rcu_read_lock();
5862 0 : rb = rcu_dereference(event->rb);
5863 0 : if (rb) {
5864 0 : list_for_each_entry_rcu(event, &rb->event_list, rb_entry)
5865 0 : wake_up_all(&event->waitq);
5866 : }
5867 0 : rcu_read_unlock();
5868 0 : }
5869 :
5870 0 : struct perf_buffer *ring_buffer_get(struct perf_event *event)
5871 : {
5872 0 : struct perf_buffer *rb;
5873 :
5874 0 : rcu_read_lock();
5875 0 : rb = rcu_dereference(event->rb);
5876 0 : if (rb) {
5877 0 : if (!refcount_inc_not_zero(&rb->refcount))
5878 0 : rb = NULL;
5879 : }
5880 0 : rcu_read_unlock();
5881 :
5882 0 : return rb;
5883 : }
5884 :
5885 0 : void ring_buffer_put(struct perf_buffer *rb)
5886 : {
5887 0 : if (!refcount_dec_and_test(&rb->refcount))
5888 : return;
5889 :
5890 0 : WARN_ON_ONCE(!list_empty(&rb->event_list));
5891 :
5892 0 : call_rcu(&rb->rcu_head, rb_free_rcu);
5893 : }
5894 :
5895 0 : static void perf_mmap_open(struct vm_area_struct *vma)
5896 : {
5897 0 : struct perf_event *event = vma->vm_file->private_data;
5898 :
5899 0 : atomic_inc(&event->mmap_count);
5900 0 : atomic_inc(&event->rb->mmap_count);
5901 :
5902 0 : if (vma->vm_pgoff)
5903 0 : atomic_inc(&event->rb->aux_mmap_count);
5904 :
5905 0 : if (event->pmu->event_mapped)
5906 0 : event->pmu->event_mapped(event, vma->vm_mm);
5907 0 : }
5908 :
5909 : static void perf_pmu_output_stop(struct perf_event *event);
5910 :
5911 : /*
5912 : * A buffer can be mmap()ed multiple times; either directly through the same
5913 : * event, or through other events by use of perf_event_set_output().
5914 : *
5915 : * In order to undo the VM accounting done by perf_mmap() we need to destroy
5916 : * the buffer here, where we still have a VM context. This means we need
5917 : * to detach all events redirecting to us.
5918 : */
5919 0 : static void perf_mmap_close(struct vm_area_struct *vma)
5920 : {
5921 0 : struct perf_event *event = vma->vm_file->private_data;
5922 0 : struct perf_buffer *rb = ring_buffer_get(event);
5923 0 : struct user_struct *mmap_user = rb->mmap_user;
5924 0 : int mmap_locked = rb->mmap_locked;
5925 0 : unsigned long size = perf_data_size(rb);
5926 0 : bool detach_rest = false;
5927 :
5928 0 : if (event->pmu->event_unmapped)
5929 0 : event->pmu->event_unmapped(event, vma->vm_mm);
5930 :
5931 : /*
5932 : * rb->aux_mmap_count will always drop before rb->mmap_count and
5933 : * event->mmap_count, so it is ok to use event->mmap_mutex to
5934 : * serialize with perf_mmap here.
5935 : */
5936 0 : if (rb_has_aux(rb) && vma->vm_pgoff == rb->aux_pgoff &&
5937 0 : atomic_dec_and_mutex_lock(&rb->aux_mmap_count, &event->mmap_mutex)) {
5938 : /*
5939 : * Stop all AUX events that are writing to this buffer,
5940 : * so that we can free its AUX pages and corresponding PMU
5941 : * data. Note that after rb::aux_mmap_count dropped to zero,
5942 : * they won't start any more (see perf_aux_output_begin()).
5943 : */
5944 0 : perf_pmu_output_stop(event);
5945 :
5946 : /* now it's safe to free the pages */
5947 0 : atomic_long_sub(rb->aux_nr_pages - rb->aux_mmap_locked, &mmap_user->locked_vm);
5948 0 : atomic64_sub(rb->aux_mmap_locked, &vma->vm_mm->pinned_vm);
5949 :
5950 : /* this has to be the last one */
5951 0 : rb_free_aux(rb);
5952 0 : WARN_ON_ONCE(refcount_read(&rb->aux_refcount));
5953 :
5954 0 : mutex_unlock(&event->mmap_mutex);
5955 : }
5956 :
5957 0 : if (atomic_dec_and_test(&rb->mmap_count))
5958 0 : detach_rest = true;
5959 :
5960 0 : if (!atomic_dec_and_mutex_lock(&event->mmap_count, &event->mmap_mutex))
5961 0 : goto out_put;
5962 :
5963 0 : ring_buffer_attach(event, NULL);
5964 0 : mutex_unlock(&event->mmap_mutex);
5965 :
5966 : /* If there's still other mmap()s of this buffer, we're done. */
5967 0 : if (!detach_rest)
5968 0 : goto out_put;
5969 :
5970 : /*
5971 : * No other mmap()s, detach from all other events that might redirect
5972 : * into the now unreachable buffer. Somewhat complicated by the
5973 : * fact that rb::event_lock otherwise nests inside mmap_mutex.
5974 : */
5975 0 : again:
5976 0 : rcu_read_lock();
5977 0 : list_for_each_entry_rcu(event, &rb->event_list, rb_entry) {
5978 0 : if (!atomic_long_inc_not_zero(&event->refcount)) {
5979 : /*
5980 : * This event is en-route to free_event() which will
5981 : * detach it and remove it from the list.
5982 : */
5983 0 : continue;
5984 : }
5985 0 : rcu_read_unlock();
5986 :
5987 0 : mutex_lock(&event->mmap_mutex);
5988 : /*
5989 : * Check we didn't race with perf_event_set_output() which can
5990 : * swizzle the rb from under us while we were waiting to
5991 : * acquire mmap_mutex.
5992 : *
5993 : * If we find a different rb; ignore this event, a next
5994 : * iteration will no longer find it on the list. We have to
5995 : * still restart the iteration to make sure we're not now
5996 : * iterating the wrong list.
5997 : */
5998 0 : if (event->rb == rb)
5999 0 : ring_buffer_attach(event, NULL);
6000 :
6001 0 : mutex_unlock(&event->mmap_mutex);
6002 0 : put_event(event);
6003 :
6004 : /*
6005 : * Restart the iteration; either we're on the wrong list or
6006 : * destroyed its integrity by doing a deletion.
6007 : */
6008 0 : goto again;
6009 : }
6010 0 : rcu_read_unlock();
6011 :
6012 : /*
6013 : * It could be there's still a few 0-ref events on the list; they'll
6014 : * get cleaned up by free_event() -- they'll also still have their
6015 : * ref on the rb and will free it whenever they are done with it.
6016 : *
6017 : * Aside from that, this buffer is 'fully' detached and unmapped,
6018 : * undo the VM accounting.
6019 : */
6020 :
6021 0 : atomic_long_sub((size >> PAGE_SHIFT) + 1 - mmap_locked,
6022 : &mmap_user->locked_vm);
6023 0 : atomic64_sub(mmap_locked, &vma->vm_mm->pinned_vm);
6024 0 : free_uid(mmap_user);
6025 :
6026 0 : out_put:
6027 0 : ring_buffer_put(rb); /* could be last */
6028 0 : }
6029 :
6030 : static const struct vm_operations_struct perf_mmap_vmops = {
6031 : .open = perf_mmap_open,
6032 : .close = perf_mmap_close, /* non mergeable */
6033 : .fault = perf_mmap_fault,
6034 : .page_mkwrite = perf_mmap_fault,
6035 : };
6036 :
6037 0 : static int perf_mmap(struct file *file, struct vm_area_struct *vma)
6038 : {
6039 0 : struct perf_event *event = file->private_data;
6040 0 : unsigned long user_locked, user_lock_limit;
6041 0 : struct user_struct *user = current_user();
6042 0 : struct perf_buffer *rb = NULL;
6043 0 : unsigned long locked, lock_limit;
6044 0 : unsigned long vma_size;
6045 0 : unsigned long nr_pages;
6046 0 : long user_extra = 0, extra = 0;
6047 0 : int ret = 0, flags = 0;
6048 :
6049 : /*
6050 : * Don't allow mmap() of inherited per-task counters. This would
6051 : * create a performance issue due to all children writing to the
6052 : * same rb.
6053 : */
6054 0 : if (event->cpu == -1 && event->attr.inherit)
6055 : return -EINVAL;
6056 :
6057 0 : if (!(vma->vm_flags & VM_SHARED))
6058 : return -EINVAL;
6059 :
6060 0 : ret = security_perf_event_read(event);
6061 0 : if (ret)
6062 : return ret;
6063 :
6064 0 : vma_size = vma->vm_end - vma->vm_start;
6065 :
6066 0 : if (vma->vm_pgoff == 0) {
6067 0 : nr_pages = (vma_size / PAGE_SIZE) - 1;
6068 : } else {
6069 : /*
6070 : * AUX area mapping: if rb->aux_nr_pages != 0, it's already
6071 : * mapped, all subsequent mappings should have the same size
6072 : * and offset. Must be above the normal perf buffer.
6073 : */
6074 0 : u64 aux_offset, aux_size;
6075 :
6076 0 : if (!event->rb)
6077 : return -EINVAL;
6078 :
6079 0 : nr_pages = vma_size / PAGE_SIZE;
6080 :
6081 0 : mutex_lock(&event->mmap_mutex);
6082 0 : ret = -EINVAL;
6083 :
6084 0 : rb = event->rb;
6085 0 : if (!rb)
6086 0 : goto aux_unlock;
6087 :
6088 0 : aux_offset = READ_ONCE(rb->user_page->aux_offset);
6089 0 : aux_size = READ_ONCE(rb->user_page->aux_size);
6090 :
6091 0 : if (aux_offset < perf_data_size(rb) + PAGE_SIZE)
6092 0 : goto aux_unlock;
6093 :
6094 0 : if (aux_offset != vma->vm_pgoff << PAGE_SHIFT)
6095 0 : goto aux_unlock;
6096 :
6097 : /* already mapped with a different offset */
6098 0 : if (rb_has_aux(rb) && rb->aux_pgoff != vma->vm_pgoff)
6099 0 : goto aux_unlock;
6100 :
6101 0 : if (aux_size != vma_size || aux_size != nr_pages * PAGE_SIZE)
6102 0 : goto aux_unlock;
6103 :
6104 : /* already mapped with a different size */
6105 0 : if (rb_has_aux(rb) && rb->aux_nr_pages != nr_pages)
6106 0 : goto aux_unlock;
6107 :
6108 0 : if (!is_power_of_2(nr_pages))
6109 0 : goto aux_unlock;
6110 :
6111 0 : if (!atomic_inc_not_zero(&rb->mmap_count))
6112 0 : goto aux_unlock;
6113 :
6114 0 : if (rb_has_aux(rb)) {
6115 0 : atomic_inc(&rb->aux_mmap_count);
6116 0 : ret = 0;
6117 0 : goto unlock;
6118 : }
6119 :
6120 0 : atomic_set(&rb->aux_mmap_count, 1);
6121 0 : user_extra = nr_pages;
6122 :
6123 0 : goto accounting;
6124 : }
6125 :
6126 : /*
6127 : * If we have rb pages ensure they're a power-of-two number, so we
6128 : * can do bitmasks instead of modulo.
6129 : */
6130 0 : if (nr_pages != 0 && !is_power_of_2(nr_pages))
6131 : return -EINVAL;
6132 :
6133 0 : if (vma_size != PAGE_SIZE * (1 + nr_pages))
6134 : return -EINVAL;
6135 :
6136 0 : WARN_ON_ONCE(event->ctx->parent_ctx);
6137 : again:
6138 0 : mutex_lock(&event->mmap_mutex);
6139 0 : if (event->rb) {
6140 0 : if (event->rb->nr_pages != nr_pages) {
6141 0 : ret = -EINVAL;
6142 0 : goto unlock;
6143 : }
6144 :
6145 0 : if (!atomic_inc_not_zero(&event->rb->mmap_count)) {
6146 : /*
6147 : * Raced against perf_mmap_close() through
6148 : * perf_event_set_output(). Try again, hope for better
6149 : * luck.
6150 : */
6151 0 : mutex_unlock(&event->mmap_mutex);
6152 0 : goto again;
6153 : }
6154 :
6155 0 : goto unlock;
6156 : }
6157 :
6158 0 : user_extra = nr_pages + 1;
6159 :
6160 0 : accounting:
6161 0 : user_lock_limit = sysctl_perf_event_mlock >> (PAGE_SHIFT - 10);
6162 :
6163 : /*
6164 : * Increase the limit linearly with more CPUs:
6165 : */
6166 0 : user_lock_limit *= num_online_cpus();
6167 :
6168 0 : user_locked = atomic_long_read(&user->locked_vm);
6169 :
6170 : /*
6171 : * sysctl_perf_event_mlock may have changed, so that
6172 : * user->locked_vm > user_lock_limit
6173 : */
6174 0 : if (user_locked > user_lock_limit)
6175 : user_locked = user_lock_limit;
6176 0 : user_locked += user_extra;
6177 :
6178 0 : if (user_locked > user_lock_limit) {
6179 : /*
6180 : * charge locked_vm until it hits user_lock_limit;
6181 : * charge the rest from pinned_vm
6182 : */
6183 0 : extra = user_locked - user_lock_limit;
6184 0 : user_extra -= extra;
6185 : }
6186 :
6187 0 : lock_limit = rlimit(RLIMIT_MEMLOCK);
6188 0 : lock_limit >>= PAGE_SHIFT;
6189 0 : locked = atomic64_read(&vma->vm_mm->pinned_vm) + extra;
6190 :
6191 0 : if ((locked > lock_limit) && perf_is_paranoid() &&
6192 0 : !capable(CAP_IPC_LOCK)) {
6193 0 : ret = -EPERM;
6194 0 : goto unlock;
6195 : }
6196 :
6197 0 : WARN_ON(!rb && event->rb);
6198 :
6199 0 : if (vma->vm_flags & VM_WRITE)
6200 0 : flags |= RING_BUFFER_WRITABLE;
6201 :
6202 0 : if (!rb) {
6203 0 : rb = rb_alloc(nr_pages,
6204 0 : event->attr.watermark ? event->attr.wakeup_watermark : 0,
6205 : event->cpu, flags);
6206 :
6207 0 : if (!rb) {
6208 0 : ret = -ENOMEM;
6209 0 : goto unlock;
6210 : }
6211 :
6212 0 : atomic_set(&rb->mmap_count, 1);
6213 0 : rb->mmap_user = get_current_user();
6214 0 : rb->mmap_locked = extra;
6215 :
6216 0 : ring_buffer_attach(event, rb);
6217 :
6218 0 : perf_event_init_userpage(event);
6219 0 : perf_event_update_userpage(event);
6220 : } else {
6221 0 : ret = rb_alloc_aux(rb, event, vma->vm_pgoff, nr_pages,
6222 0 : event->attr.aux_watermark, flags);
6223 0 : if (!ret)
6224 0 : rb->aux_mmap_locked = extra;
6225 : }
6226 :
6227 0 : unlock:
6228 0 : if (!ret) {
6229 0 : atomic_long_add(user_extra, &user->locked_vm);
6230 0 : atomic64_add(extra, &vma->vm_mm->pinned_vm);
6231 :
6232 0 : atomic_inc(&event->mmap_count);
6233 0 : } else if (rb) {
6234 0 : atomic_dec(&rb->mmap_count);
6235 : }
6236 0 : aux_unlock:
6237 0 : mutex_unlock(&event->mmap_mutex);
6238 :
6239 : /*
6240 : * Since pinned accounting is per vm we cannot allow fork() to copy our
6241 : * vma.
6242 : */
6243 0 : vma->vm_flags |= VM_DONTCOPY | VM_DONTEXPAND | VM_DONTDUMP;
6244 0 : vma->vm_ops = &perf_mmap_vmops;
6245 :
6246 0 : if (event->pmu->event_mapped)
6247 0 : event->pmu->event_mapped(event, vma->vm_mm);
6248 :
6249 : return ret;
6250 : }
6251 :
6252 0 : static int perf_fasync(int fd, struct file *filp, int on)
6253 : {
6254 0 : struct inode *inode = file_inode(filp);
6255 0 : struct perf_event *event = filp->private_data;
6256 0 : int retval;
6257 :
6258 0 : inode_lock(inode);
6259 0 : retval = fasync_helper(fd, filp, on, &event->fasync);
6260 0 : inode_unlock(inode);
6261 :
6262 0 : if (retval < 0)
6263 : return retval;
6264 :
6265 : return 0;
6266 : }
6267 :
6268 : static const struct file_operations perf_fops = {
6269 : .llseek = no_llseek,
6270 : .release = perf_release,
6271 : .read = perf_read,
6272 : .poll = perf_poll,
6273 : .unlocked_ioctl = perf_ioctl,
6274 : .compat_ioctl = perf_compat_ioctl,
6275 : .mmap = perf_mmap,
6276 : .fasync = perf_fasync,
6277 : };
6278 :
6279 : /*
6280 : * Perf event wakeup
6281 : *
6282 : * If there's data, ensure we set the poll() state and publish everything
6283 : * to user-space before waking everybody up.
6284 : */
6285 :
6286 0 : static inline struct fasync_struct **perf_event_fasync(struct perf_event *event)
6287 : {
6288 : /* only the parent has fasync state */
6289 0 : if (event->parent)
6290 0 : event = event->parent;
6291 0 : return &event->fasync;
6292 : }
6293 :
6294 0 : void perf_event_wakeup(struct perf_event *event)
6295 : {
6296 0 : ring_buffer_wakeup(event);
6297 :
6298 0 : if (event->pending_kill) {
6299 0 : kill_fasync(perf_event_fasync(event), SIGIO, event->pending_kill);
6300 0 : event->pending_kill = 0;
6301 : }
6302 0 : }
6303 :
6304 0 : static void perf_pending_event_disable(struct perf_event *event)
6305 : {
6306 0 : int cpu = READ_ONCE(event->pending_disable);
6307 :
6308 0 : if (cpu < 0)
6309 : return;
6310 :
6311 0 : if (cpu == smp_processor_id()) {
6312 0 : WRITE_ONCE(event->pending_disable, -1);
6313 0 : perf_event_disable_local(event);
6314 0 : return;
6315 : }
6316 :
6317 : /*
6318 : * CPU-A CPU-B
6319 : *
6320 : * perf_event_disable_inatomic()
6321 : * @pending_disable = CPU-A;
6322 : * irq_work_queue();
6323 : *
6324 : * sched-out
6325 : * @pending_disable = -1;
6326 : *
6327 : * sched-in
6328 : * perf_event_disable_inatomic()
6329 : * @pending_disable = CPU-B;
6330 : * irq_work_queue(); // FAILS
6331 : *
6332 : * irq_work_run()
6333 : * perf_pending_event()
6334 : *
6335 : * But the event runs on CPU-B and wants disabling there.
6336 : */
6337 0 : irq_work_queue_on(&event->pending, cpu);
6338 : }
6339 :
6340 0 : static void perf_pending_event(struct irq_work *entry)
6341 : {
6342 0 : struct perf_event *event = container_of(entry, struct perf_event, pending);
6343 0 : int rctx;
6344 :
6345 0 : rctx = perf_swevent_get_recursion_context();
6346 : /*
6347 : * If we 'fail' here, that's OK, it means recursion is already disabled
6348 : * and we won't recurse 'further'.
6349 : */
6350 :
6351 0 : perf_pending_event_disable(event);
6352 :
6353 0 : if (event->pending_wakeup) {
6354 0 : event->pending_wakeup = 0;
6355 0 : perf_event_wakeup(event);
6356 : }
6357 :
6358 0 : if (rctx >= 0)
6359 0 : perf_swevent_put_recursion_context(rctx);
6360 0 : }
6361 :
6362 : /*
6363 : * We assume there is only KVM supporting the callbacks.
6364 : * Later on, we might change it to a list if there is
6365 : * another virtualization implementation supporting the callbacks.
6366 : */
6367 : struct perf_guest_info_callbacks *perf_guest_cbs;
6368 :
6369 0 : int perf_register_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
6370 : {
6371 0 : perf_guest_cbs = cbs;
6372 0 : return 0;
6373 : }
6374 : EXPORT_SYMBOL_GPL(perf_register_guest_info_callbacks);
6375 :
6376 0 : int perf_unregister_guest_info_callbacks(struct perf_guest_info_callbacks *cbs)
6377 : {
6378 0 : perf_guest_cbs = NULL;
6379 0 : return 0;
6380 : }
6381 : EXPORT_SYMBOL_GPL(perf_unregister_guest_info_callbacks);
6382 :
6383 : static void
6384 0 : perf_output_sample_regs(struct perf_output_handle *handle,
6385 : struct pt_regs *regs, u64 mask)
6386 : {
6387 0 : int bit;
6388 0 : DECLARE_BITMAP(_mask, 64);
6389 :
6390 0 : bitmap_from_u64(_mask, mask);
6391 0 : for_each_set_bit(bit, _mask, sizeof(mask) * BITS_PER_BYTE) {
6392 0 : u64 val;
6393 :
6394 0 : val = perf_reg_value(regs, bit);
6395 0 : perf_output_put(handle, val);
6396 : }
6397 0 : }
6398 :
6399 0 : static void perf_sample_regs_user(struct perf_regs *regs_user,
6400 : struct pt_regs *regs)
6401 : {
6402 0 : if (user_mode(regs)) {
6403 0 : regs_user->abi = perf_reg_abi(current);
6404 0 : regs_user->regs = regs;
6405 0 : } else if (!(current->flags & PF_KTHREAD)) {
6406 0 : perf_get_regs_user(regs_user, regs);
6407 : } else {
6408 0 : regs_user->abi = PERF_SAMPLE_REGS_ABI_NONE;
6409 0 : regs_user->regs = NULL;
6410 : }
6411 0 : }
6412 :
6413 0 : static void perf_sample_regs_intr(struct perf_regs *regs_intr,
6414 : struct pt_regs *regs)
6415 : {
6416 0 : regs_intr->regs = regs;
6417 0 : regs_intr->abi = perf_reg_abi(current);
6418 : }
6419 :
6420 :
6421 : /*
6422 : * Get remaining task size from user stack pointer.
6423 : *
6424 : * It'd be better to take stack vma map and limit this more
6425 : * precisely, but there's no way to get it safely under interrupt,
6426 : * so using TASK_SIZE as limit.
6427 : */
6428 0 : static u64 perf_ustack_task_size(struct pt_regs *regs)
6429 : {
6430 0 : unsigned long addr = perf_user_stack_pointer(regs);
6431 :
6432 0 : if (!addr || addr >= TASK_SIZE)
6433 0 : return 0;
6434 :
6435 0 : return TASK_SIZE - addr;
6436 : }
6437 :
6438 : static u16
6439 0 : perf_sample_ustack_size(u16 stack_size, u16 header_size,
6440 : struct pt_regs *regs)
6441 : {
6442 0 : u64 task_size;
6443 :
6444 : /* No regs, no stack pointer, no dump. */
6445 0 : if (!regs)
6446 : return 0;
6447 :
6448 : /*
6449 : * Check if we fit in with the requested stack size into the:
6450 : * - TASK_SIZE
6451 : * If we don't, we limit the size to the TASK_SIZE.
6452 : *
6453 : * - remaining sample size
6454 : * If we don't, we customize the stack size to
6455 : * fit in to the remaining sample size.
6456 : */
6457 :
6458 0 : task_size = min((u64) USHRT_MAX, perf_ustack_task_size(regs));
6459 0 : stack_size = min(stack_size, (u16) task_size);
6460 :
6461 : /* Current header size plus static size and dynamic size. */
6462 0 : header_size += 2 * sizeof(u64);
6463 :
6464 : /* Do we fit in with the current stack dump size? */
6465 0 : if ((u16) (header_size + stack_size) < header_size) {
6466 : /*
6467 : * If we overflow the maximum size for the sample,
6468 : * we customize the stack dump size to fit in.
6469 : */
6470 0 : stack_size = USHRT_MAX - header_size - sizeof(u64);
6471 0 : stack_size = round_up(stack_size, sizeof(u64));
6472 : }
6473 :
6474 : return stack_size;
6475 : }
6476 :
6477 : static void
6478 0 : perf_output_sample_ustack(struct perf_output_handle *handle, u64 dump_size,
6479 : struct pt_regs *regs)
6480 : {
6481 : /* Case of a kernel thread, nothing to dump */
6482 0 : if (!regs) {
6483 0 : u64 size = 0;
6484 0 : perf_output_put(handle, size);
6485 : } else {
6486 0 : unsigned long sp;
6487 0 : unsigned int rem;
6488 0 : u64 dyn_size;
6489 0 : mm_segment_t fs;
6490 :
6491 : /*
6492 : * We dump:
6493 : * static size
6494 : * - the size requested by user or the best one we can fit
6495 : * in to the sample max size
6496 : * data
6497 : * - user stack dump data
6498 : * dynamic size
6499 : * - the actual dumped size
6500 : */
6501 :
6502 : /* Static size. */
6503 0 : perf_output_put(handle, dump_size);
6504 :
6505 : /* Data. */
6506 0 : sp = perf_user_stack_pointer(regs);
6507 0 : fs = force_uaccess_begin();
6508 0 : rem = __output_copy_user(handle, (void *) sp, dump_size);
6509 0 : force_uaccess_end(fs);
6510 0 : dyn_size = dump_size - rem;
6511 :
6512 0 : perf_output_skip(handle, rem);
6513 :
6514 : /* Dynamic size. */
6515 0 : perf_output_put(handle, dyn_size);
6516 : }
6517 0 : }
6518 :
6519 0 : static unsigned long perf_prepare_sample_aux(struct perf_event *event,
6520 : struct perf_sample_data *data,
6521 : size_t size)
6522 : {
6523 0 : struct perf_event *sampler = event->aux_event;
6524 0 : struct perf_buffer *rb;
6525 :
6526 0 : data->aux_size = 0;
6527 :
6528 0 : if (!sampler)
6529 0 : goto out;
6530 :
6531 0 : if (WARN_ON_ONCE(READ_ONCE(sampler->state) != PERF_EVENT_STATE_ACTIVE))
6532 0 : goto out;
6533 :
6534 0 : if (WARN_ON_ONCE(READ_ONCE(sampler->oncpu) != smp_processor_id()))
6535 0 : goto out;
6536 :
6537 0 : rb = ring_buffer_get(sampler->parent ? sampler->parent : sampler);
6538 0 : if (!rb)
6539 0 : goto out;
6540 :
6541 : /*
6542 : * If this is an NMI hit inside sampling code, don't take
6543 : * the sample. See also perf_aux_sample_output().
6544 : */
6545 0 : if (READ_ONCE(rb->aux_in_sampling)) {
6546 0 : data->aux_size = 0;
6547 : } else {
6548 0 : size = min_t(size_t, size, perf_aux_size(rb));
6549 0 : data->aux_size = ALIGN(size, sizeof(u64));
6550 : }
6551 0 : ring_buffer_put(rb);
6552 :
6553 0 : out:
6554 0 : return data->aux_size;
6555 : }
6556 :
6557 0 : long perf_pmu_snapshot_aux(struct perf_buffer *rb,
6558 : struct perf_event *event,
6559 : struct perf_output_handle *handle,
6560 : unsigned long size)
6561 : {
6562 0 : unsigned long flags;
6563 0 : long ret;
6564 :
6565 : /*
6566 : * Normal ->start()/->stop() callbacks run in IRQ mode in scheduler
6567 : * paths. If we start calling them in NMI context, they may race with
6568 : * the IRQ ones, that is, for example, re-starting an event that's just
6569 : * been stopped, which is why we're using a separate callback that
6570 : * doesn't change the event state.
6571 : *
6572 : * IRQs need to be disabled to prevent IPIs from racing with us.
6573 : */
6574 0 : local_irq_save(flags);
6575 : /*
6576 : * Guard against NMI hits inside the critical section;
6577 : * see also perf_prepare_sample_aux().
6578 : */
6579 0 : WRITE_ONCE(rb->aux_in_sampling, 1);
6580 0 : barrier();
6581 :
6582 0 : ret = event->pmu->snapshot_aux(event, handle, size);
6583 :
6584 0 : barrier();
6585 0 : WRITE_ONCE(rb->aux_in_sampling, 0);
6586 0 : local_irq_restore(flags);
6587 :
6588 0 : return ret;
6589 : }
6590 :
6591 0 : static void perf_aux_sample_output(struct perf_event *event,
6592 : struct perf_output_handle *handle,
6593 : struct perf_sample_data *data)
6594 : {
6595 0 : struct perf_event *sampler = event->aux_event;
6596 0 : struct perf_buffer *rb;
6597 0 : unsigned long pad;
6598 0 : long size;
6599 :
6600 0 : if (WARN_ON_ONCE(!sampler || !data->aux_size))
6601 : return;
6602 :
6603 0 : rb = ring_buffer_get(sampler->parent ? sampler->parent : sampler);
6604 0 : if (!rb)
6605 : return;
6606 :
6607 0 : size = perf_pmu_snapshot_aux(rb, sampler, handle, data->aux_size);
6608 :
6609 : /*
6610 : * An error here means that perf_output_copy() failed (returned a
6611 : * non-zero surplus that it didn't copy), which in its current
6612 : * enlightened implementation is not possible. If that changes, we'd
6613 : * like to know.
6614 : */
6615 0 : if (WARN_ON_ONCE(size < 0))
6616 0 : goto out_put;
6617 :
6618 : /*
6619 : * The pad comes from ALIGN()ing data->aux_size up to u64 in
6620 : * perf_prepare_sample_aux(), so should not be more than that.
6621 : */
6622 0 : pad = data->aux_size - size;
6623 0 : if (WARN_ON_ONCE(pad >= sizeof(u64)))
6624 : pad = 8;
6625 :
6626 0 : if (pad) {
6627 0 : u64 zero = 0;
6628 0 : perf_output_copy(handle, &zero, pad);
6629 : }
6630 :
6631 0 : out_put:
6632 0 : ring_buffer_put(rb);
6633 : }
6634 :
6635 0 : static void __perf_event_header__init_id(struct perf_event_header *header,
6636 : struct perf_sample_data *data,
6637 : struct perf_event *event)
6638 : {
6639 0 : u64 sample_type = event->attr.sample_type;
6640 :
6641 0 : data->type = sample_type;
6642 0 : header->size += event->id_header_size;
6643 :
6644 0 : if (sample_type & PERF_SAMPLE_TID) {
6645 : /* namespace issues */
6646 0 : data->tid_entry.pid = perf_event_pid(event, current);
6647 0 : data->tid_entry.tid = perf_event_tid(event, current);
6648 : }
6649 :
6650 0 : if (sample_type & PERF_SAMPLE_TIME)
6651 0 : data->time = perf_event_clock(event);
6652 :
6653 0 : if (sample_type & (PERF_SAMPLE_ID | PERF_SAMPLE_IDENTIFIER))
6654 0 : data->id = primary_event_id(event);
6655 :
6656 0 : if (sample_type & PERF_SAMPLE_STREAM_ID)
6657 0 : data->stream_id = event->id;
6658 :
6659 0 : if (sample_type & PERF_SAMPLE_CPU) {
6660 0 : data->cpu_entry.cpu = raw_smp_processor_id();
6661 0 : data->cpu_entry.reserved = 0;
6662 : }
6663 0 : }
6664 :
6665 0 : void perf_event_header__init_id(struct perf_event_header *header,
6666 : struct perf_sample_data *data,
6667 : struct perf_event *event)
6668 : {
6669 0 : if (event->attr.sample_id_all)
6670 0 : __perf_event_header__init_id(header, data, event);
6671 0 : }
6672 :
6673 0 : static void __perf_event__output_id_sample(struct perf_output_handle *handle,
6674 : struct perf_sample_data *data)
6675 : {
6676 0 : u64 sample_type = data->type;
6677 :
6678 0 : if (sample_type & PERF_SAMPLE_TID)
6679 0 : perf_output_put(handle, data->tid_entry);
6680 :
6681 0 : if (sample_type & PERF_SAMPLE_TIME)
6682 0 : perf_output_put(handle, data->time);
6683 :
6684 0 : if (sample_type & PERF_SAMPLE_ID)
6685 0 : perf_output_put(handle, data->id);
6686 :
6687 0 : if (sample_type & PERF_SAMPLE_STREAM_ID)
6688 0 : perf_output_put(handle, data->stream_id);
6689 :
6690 0 : if (sample_type & PERF_SAMPLE_CPU)
6691 0 : perf_output_put(handle, data->cpu_entry);
6692 :
6693 0 : if (sample_type & PERF_SAMPLE_IDENTIFIER)
6694 0 : perf_output_put(handle, data->id);
6695 0 : }
6696 :
6697 0 : void perf_event__output_id_sample(struct perf_event *event,
6698 : struct perf_output_handle *handle,
6699 : struct perf_sample_data *sample)
6700 : {
6701 0 : if (event->attr.sample_id_all)
6702 0 : __perf_event__output_id_sample(handle, sample);
6703 0 : }
6704 :
6705 0 : static void perf_output_read_one(struct perf_output_handle *handle,
6706 : struct perf_event *event,
6707 : u64 enabled, u64 running)
6708 : {
6709 0 : u64 read_format = event->attr.read_format;
6710 0 : u64 values[4];
6711 0 : int n = 0;
6712 :
6713 0 : values[n++] = perf_event_count(event);
6714 0 : if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
6715 0 : values[n++] = enabled +
6716 0 : atomic64_read(&event->child_total_time_enabled);
6717 : }
6718 0 : if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
6719 0 : values[n++] = running +
6720 0 : atomic64_read(&event->child_total_time_running);
6721 : }
6722 0 : if (read_format & PERF_FORMAT_ID)
6723 0 : values[n++] = primary_event_id(event);
6724 :
6725 0 : __output_copy(handle, values, n * sizeof(u64));
6726 0 : }
6727 :
6728 0 : static void perf_output_read_group(struct perf_output_handle *handle,
6729 : struct perf_event *event,
6730 : u64 enabled, u64 running)
6731 : {
6732 0 : struct perf_event *leader = event->group_leader, *sub;
6733 0 : u64 read_format = event->attr.read_format;
6734 0 : u64 values[5];
6735 0 : int n = 0;
6736 :
6737 0 : values[n++] = 1 + leader->nr_siblings;
6738 :
6739 0 : if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED)
6740 0 : values[n++] = enabled;
6741 :
6742 0 : if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING)
6743 0 : values[n++] = running;
6744 :
6745 0 : if ((leader != event) &&
6746 0 : (leader->state == PERF_EVENT_STATE_ACTIVE))
6747 0 : leader->pmu->read(leader);
6748 :
6749 0 : values[n++] = perf_event_count(leader);
6750 0 : if (read_format & PERF_FORMAT_ID)
6751 0 : values[n++] = primary_event_id(leader);
6752 :
6753 0 : __output_copy(handle, values, n * sizeof(u64));
6754 :
6755 0 : for_each_sibling_event(sub, leader) {
6756 0 : n = 0;
6757 :
6758 0 : if ((sub != event) &&
6759 0 : (sub->state == PERF_EVENT_STATE_ACTIVE))
6760 0 : sub->pmu->read(sub);
6761 :
6762 0 : values[n++] = perf_event_count(sub);
6763 0 : if (read_format & PERF_FORMAT_ID)
6764 0 : values[n++] = primary_event_id(sub);
6765 :
6766 0 : __output_copy(handle, values, n * sizeof(u64));
6767 : }
6768 0 : }
6769 :
6770 : #define PERF_FORMAT_TOTAL_TIMES (PERF_FORMAT_TOTAL_TIME_ENABLED|\
6771 : PERF_FORMAT_TOTAL_TIME_RUNNING)
6772 :
6773 : /*
6774 : * XXX PERF_SAMPLE_READ vs inherited events seems difficult.
6775 : *
6776 : * The problem is that its both hard and excessively expensive to iterate the
6777 : * child list, not to mention that its impossible to IPI the children running
6778 : * on another CPU, from interrupt/NMI context.
6779 : */
6780 0 : static void perf_output_read(struct perf_output_handle *handle,
6781 : struct perf_event *event)
6782 : {
6783 0 : u64 enabled = 0, running = 0, now;
6784 0 : u64 read_format = event->attr.read_format;
6785 :
6786 : /*
6787 : * compute total_time_enabled, total_time_running
6788 : * based on snapshot values taken when the event
6789 : * was last scheduled in.
6790 : *
6791 : * we cannot simply called update_context_time()
6792 : * because of locking issue as we are called in
6793 : * NMI context
6794 : */
6795 0 : if (read_format & PERF_FORMAT_TOTAL_TIMES)
6796 0 : calc_timer_values(event, &now, &enabled, &running);
6797 :
6798 0 : if (event->attr.read_format & PERF_FORMAT_GROUP)
6799 0 : perf_output_read_group(handle, event, enabled, running);
6800 : else
6801 0 : perf_output_read_one(handle, event, enabled, running);
6802 0 : }
6803 :
6804 0 : static inline bool perf_sample_save_hw_index(struct perf_event *event)
6805 : {
6806 0 : return event->attr.branch_sample_type & PERF_SAMPLE_BRANCH_HW_INDEX;
6807 : }
6808 :
6809 0 : void perf_output_sample(struct perf_output_handle *handle,
6810 : struct perf_event_header *header,
6811 : struct perf_sample_data *data,
6812 : struct perf_event *event)
6813 : {
6814 0 : u64 sample_type = data->type;
6815 :
6816 0 : perf_output_put(handle, *header);
6817 :
6818 0 : if (sample_type & PERF_SAMPLE_IDENTIFIER)
6819 0 : perf_output_put(handle, data->id);
6820 :
6821 0 : if (sample_type & PERF_SAMPLE_IP)
6822 0 : perf_output_put(handle, data->ip);
6823 :
6824 0 : if (sample_type & PERF_SAMPLE_TID)
6825 0 : perf_output_put(handle, data->tid_entry);
6826 :
6827 0 : if (sample_type & PERF_SAMPLE_TIME)
6828 0 : perf_output_put(handle, data->time);
6829 :
6830 0 : if (sample_type & PERF_SAMPLE_ADDR)
6831 0 : perf_output_put(handle, data->addr);
6832 :
6833 0 : if (sample_type & PERF_SAMPLE_ID)
6834 0 : perf_output_put(handle, data->id);
6835 :
6836 0 : if (sample_type & PERF_SAMPLE_STREAM_ID)
6837 0 : perf_output_put(handle, data->stream_id);
6838 :
6839 0 : if (sample_type & PERF_SAMPLE_CPU)
6840 0 : perf_output_put(handle, data->cpu_entry);
6841 :
6842 0 : if (sample_type & PERF_SAMPLE_PERIOD)
6843 0 : perf_output_put(handle, data->period);
6844 :
6845 0 : if (sample_type & PERF_SAMPLE_READ)
6846 0 : perf_output_read(handle, event);
6847 :
6848 0 : if (sample_type & PERF_SAMPLE_CALLCHAIN) {
6849 0 : int size = 1;
6850 :
6851 0 : size += data->callchain->nr;
6852 0 : size *= sizeof(u64);
6853 0 : __output_copy(handle, data->callchain, size);
6854 : }
6855 :
6856 0 : if (sample_type & PERF_SAMPLE_RAW) {
6857 0 : struct perf_raw_record *raw = data->raw;
6858 :
6859 0 : if (raw) {
6860 0 : struct perf_raw_frag *frag = &raw->frag;
6861 :
6862 0 : perf_output_put(handle, raw->size);
6863 0 : do {
6864 0 : if (frag->copy) {
6865 0 : __output_custom(handle, frag->copy,
6866 0 : frag->data, frag->size);
6867 : } else {
6868 0 : __output_copy(handle, frag->data,
6869 0 : frag->size);
6870 : }
6871 0 : if (perf_raw_frag_last(frag))
6872 : break;
6873 0 : frag = frag->next;
6874 0 : } while (1);
6875 0 : if (frag->pad)
6876 0 : __output_skip(handle, NULL, frag->pad);
6877 : } else {
6878 0 : struct {
6879 : u32 size;
6880 : u32 data;
6881 0 : } raw = {
6882 : .size = sizeof(u32),
6883 : .data = 0,
6884 : };
6885 0 : perf_output_put(handle, raw);
6886 : }
6887 : }
6888 :
6889 0 : if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
6890 0 : if (data->br_stack) {
6891 0 : size_t size;
6892 :
6893 0 : size = data->br_stack->nr
6894 : * sizeof(struct perf_branch_entry);
6895 :
6896 0 : perf_output_put(handle, data->br_stack->nr);
6897 0 : if (perf_sample_save_hw_index(event))
6898 0 : perf_output_put(handle, data->br_stack->hw_idx);
6899 0 : perf_output_copy(handle, data->br_stack->entries, size);
6900 : } else {
6901 : /*
6902 : * we always store at least the value of nr
6903 : */
6904 0 : u64 nr = 0;
6905 0 : perf_output_put(handle, nr);
6906 : }
6907 : }
6908 :
6909 0 : if (sample_type & PERF_SAMPLE_REGS_USER) {
6910 0 : u64 abi = data->regs_user.abi;
6911 :
6912 : /*
6913 : * If there are no regs to dump, notice it through
6914 : * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6915 : */
6916 0 : perf_output_put(handle, abi);
6917 :
6918 0 : if (abi) {
6919 0 : u64 mask = event->attr.sample_regs_user;
6920 0 : perf_output_sample_regs(handle,
6921 : data->regs_user.regs,
6922 : mask);
6923 : }
6924 : }
6925 :
6926 0 : if (sample_type & PERF_SAMPLE_STACK_USER) {
6927 0 : perf_output_sample_ustack(handle,
6928 : data->stack_user_size,
6929 : data->regs_user.regs);
6930 : }
6931 :
6932 0 : if (sample_type & PERF_SAMPLE_WEIGHT_TYPE)
6933 0 : perf_output_put(handle, data->weight.full);
6934 :
6935 0 : if (sample_type & PERF_SAMPLE_DATA_SRC)
6936 0 : perf_output_put(handle, data->data_src.val);
6937 :
6938 0 : if (sample_type & PERF_SAMPLE_TRANSACTION)
6939 0 : perf_output_put(handle, data->txn);
6940 :
6941 0 : if (sample_type & PERF_SAMPLE_REGS_INTR) {
6942 0 : u64 abi = data->regs_intr.abi;
6943 : /*
6944 : * If there are no regs to dump, notice it through
6945 : * first u64 being zero (PERF_SAMPLE_REGS_ABI_NONE).
6946 : */
6947 0 : perf_output_put(handle, abi);
6948 :
6949 0 : if (abi) {
6950 0 : u64 mask = event->attr.sample_regs_intr;
6951 :
6952 0 : perf_output_sample_regs(handle,
6953 : data->regs_intr.regs,
6954 : mask);
6955 : }
6956 : }
6957 :
6958 0 : if (sample_type & PERF_SAMPLE_PHYS_ADDR)
6959 0 : perf_output_put(handle, data->phys_addr);
6960 :
6961 0 : if (sample_type & PERF_SAMPLE_CGROUP)
6962 0 : perf_output_put(handle, data->cgroup);
6963 :
6964 0 : if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE)
6965 0 : perf_output_put(handle, data->data_page_size);
6966 :
6967 0 : if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE)
6968 0 : perf_output_put(handle, data->code_page_size);
6969 :
6970 0 : if (sample_type & PERF_SAMPLE_AUX) {
6971 0 : perf_output_put(handle, data->aux_size);
6972 :
6973 0 : if (data->aux_size)
6974 0 : perf_aux_sample_output(event, handle, data);
6975 : }
6976 :
6977 0 : if (!event->attr.watermark) {
6978 0 : int wakeup_events = event->attr.wakeup_events;
6979 :
6980 0 : if (wakeup_events) {
6981 0 : struct perf_buffer *rb = handle->rb;
6982 0 : int events = local_inc_return(&rb->events);
6983 :
6984 0 : if (events >= wakeup_events) {
6985 0 : local_sub(wakeup_events, &rb->events);
6986 0 : local_inc(&rb->wakeup);
6987 : }
6988 : }
6989 : }
6990 0 : }
6991 :
6992 0 : static u64 perf_virt_to_phys(u64 virt)
6993 : {
6994 0 : u64 phys_addr = 0;
6995 0 : struct page *p = NULL;
6996 :
6997 0 : if (!virt)
6998 : return 0;
6999 :
7000 0 : if (virt >= TASK_SIZE) {
7001 : /* If it's vmalloc()d memory, leave phys_addr as 0 */
7002 0 : if (virt_addr_valid((void *)(uintptr_t)virt) &&
7003 0 : !(virt >= VMALLOC_START && virt < VMALLOC_END))
7004 0 : phys_addr = (u64)virt_to_phys((void *)(uintptr_t)virt);
7005 : } else {
7006 : /*
7007 : * Walking the pages tables for user address.
7008 : * Interrupts are disabled, so it prevents any tear down
7009 : * of the page tables.
7010 : * Try IRQ-safe get_user_page_fast_only first.
7011 : * If failed, leave phys_addr as 0.
7012 : */
7013 0 : if (current->mm != NULL) {
7014 0 : pagefault_disable();
7015 0 : if (get_user_page_fast_only(virt, 0, &p))
7016 0 : phys_addr = page_to_phys(p) + virt % PAGE_SIZE;
7017 0 : pagefault_enable();
7018 : }
7019 :
7020 0 : if (p)
7021 0 : put_page(p);
7022 : }
7023 :
7024 : return phys_addr;
7025 : }
7026 :
7027 : /*
7028 : * Return the pagetable size of a given virtual address.
7029 : */
7030 0 : static u64 perf_get_pgtable_size(struct mm_struct *mm, unsigned long addr)
7031 : {
7032 0 : u64 size = 0;
7033 :
7034 : #ifdef CONFIG_HAVE_FAST_GUP
7035 0 : pgd_t *pgdp, pgd;
7036 0 : p4d_t *p4dp, p4d;
7037 0 : pud_t *pudp, pud;
7038 0 : pmd_t *pmdp, pmd;
7039 0 : pte_t *ptep, pte;
7040 :
7041 0 : pgdp = pgd_offset(mm, addr);
7042 0 : pgd = READ_ONCE(*pgdp);
7043 0 : if (pgd_none(pgd))
7044 : return 0;
7045 :
7046 0 : if (pgd_leaf(pgd))
7047 : return pgd_leaf_size(pgd);
7048 :
7049 0 : p4dp = p4d_offset_lockless(pgdp, pgd, addr);
7050 0 : p4d = READ_ONCE(*p4dp);
7051 0 : if (!p4d_present(p4d))
7052 : return 0;
7053 :
7054 0 : if (p4d_leaf(p4d))
7055 : return p4d_leaf_size(p4d);
7056 :
7057 0 : pudp = pud_offset_lockless(p4dp, p4d, addr);
7058 0 : pud = READ_ONCE(*pudp);
7059 0 : if (!pud_present(pud))
7060 : return 0;
7061 :
7062 0 : if (pud_leaf(pud))
7063 : return pud_leaf_size(pud);
7064 :
7065 0 : pmdp = pmd_offset_lockless(pudp, pud, addr);
7066 0 : pmd = READ_ONCE(*pmdp);
7067 0 : if (!pmd_present(pmd))
7068 : return 0;
7069 :
7070 0 : if (pmd_leaf(pmd))
7071 : return pmd_leaf_size(pmd);
7072 :
7073 0 : ptep = pte_offset_map(&pmd, addr);
7074 0 : pte = ptep_get_lockless(ptep);
7075 0 : if (pte_present(pte))
7076 0 : size = pte_leaf_size(pte);
7077 : pte_unmap(ptep);
7078 : #endif /* CONFIG_HAVE_FAST_GUP */
7079 :
7080 : return size;
7081 : }
7082 :
7083 0 : static u64 perf_get_page_size(unsigned long addr)
7084 : {
7085 0 : struct mm_struct *mm;
7086 0 : unsigned long flags;
7087 0 : u64 size;
7088 :
7089 0 : if (!addr)
7090 : return 0;
7091 :
7092 : /*
7093 : * Software page-table walkers must disable IRQs,
7094 : * which prevents any tear down of the page tables.
7095 : */
7096 0 : local_irq_save(flags);
7097 :
7098 0 : mm = current->mm;
7099 0 : if (!mm) {
7100 : /*
7101 : * For kernel threads and the like, use init_mm so that
7102 : * we can find kernel memory.
7103 : */
7104 0 : mm = &init_mm;
7105 : }
7106 :
7107 0 : size = perf_get_pgtable_size(mm, addr);
7108 :
7109 0 : local_irq_restore(flags);
7110 :
7111 : return size;
7112 : }
7113 :
7114 : static struct perf_callchain_entry __empty_callchain = { .nr = 0, };
7115 :
7116 : struct perf_callchain_entry *
7117 0 : perf_callchain(struct perf_event *event, struct pt_regs *regs)
7118 : {
7119 0 : bool kernel = !event->attr.exclude_callchain_kernel;
7120 0 : bool user = !event->attr.exclude_callchain_user;
7121 : /* Disallow cross-task user callchains. */
7122 0 : bool crosstask = event->ctx->task && event->ctx->task != current;
7123 0 : const u32 max_stack = event->attr.sample_max_stack;
7124 0 : struct perf_callchain_entry *callchain;
7125 :
7126 0 : if (!kernel && !user)
7127 : return &__empty_callchain;
7128 :
7129 0 : callchain = get_perf_callchain(regs, 0, kernel, user,
7130 : max_stack, crosstask, true);
7131 0 : return callchain ?: &__empty_callchain;
7132 : }
7133 :
7134 0 : void perf_prepare_sample(struct perf_event_header *header,
7135 : struct perf_sample_data *data,
7136 : struct perf_event *event,
7137 : struct pt_regs *regs)
7138 : {
7139 0 : u64 sample_type = event->attr.sample_type;
7140 :
7141 0 : header->type = PERF_RECORD_SAMPLE;
7142 0 : header->size = sizeof(*header) + event->header_size;
7143 :
7144 0 : header->misc = 0;
7145 0 : header->misc |= perf_misc_flags(regs);
7146 :
7147 0 : __perf_event_header__init_id(header, data, event);
7148 :
7149 0 : if (sample_type & (PERF_SAMPLE_IP | PERF_SAMPLE_CODE_PAGE_SIZE))
7150 0 : data->ip = perf_instruction_pointer(regs);
7151 :
7152 0 : if (sample_type & PERF_SAMPLE_CALLCHAIN) {
7153 0 : int size = 1;
7154 :
7155 0 : if (!(sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY))
7156 0 : data->callchain = perf_callchain(event, regs);
7157 :
7158 0 : size += data->callchain->nr;
7159 :
7160 0 : header->size += size * sizeof(u64);
7161 : }
7162 :
7163 0 : if (sample_type & PERF_SAMPLE_RAW) {
7164 0 : struct perf_raw_record *raw = data->raw;
7165 0 : int size;
7166 :
7167 0 : if (raw) {
7168 0 : struct perf_raw_frag *frag = &raw->frag;
7169 0 : u32 sum = 0;
7170 :
7171 0 : do {
7172 0 : sum += frag->size;
7173 0 : if (perf_raw_frag_last(frag))
7174 : break;
7175 0 : frag = frag->next;
7176 0 : } while (1);
7177 :
7178 0 : size = round_up(sum + sizeof(u32), sizeof(u64));
7179 0 : raw->size = size - sizeof(u32);
7180 0 : frag->pad = raw->size - sum;
7181 : } else {
7182 : size = sizeof(u64);
7183 : }
7184 :
7185 0 : header->size += size;
7186 : }
7187 :
7188 0 : if (sample_type & PERF_SAMPLE_BRANCH_STACK) {
7189 0 : int size = sizeof(u64); /* nr */
7190 0 : if (data->br_stack) {
7191 0 : if (perf_sample_save_hw_index(event))
7192 0 : size += sizeof(u64);
7193 :
7194 0 : size += data->br_stack->nr
7195 : * sizeof(struct perf_branch_entry);
7196 : }
7197 0 : header->size += size;
7198 : }
7199 :
7200 0 : if (sample_type & (PERF_SAMPLE_REGS_USER | PERF_SAMPLE_STACK_USER))
7201 0 : perf_sample_regs_user(&data->regs_user, regs);
7202 :
7203 0 : if (sample_type & PERF_SAMPLE_REGS_USER) {
7204 : /* regs dump ABI info */
7205 0 : int size = sizeof(u64);
7206 :
7207 0 : if (data->regs_user.regs) {
7208 0 : u64 mask = event->attr.sample_regs_user;
7209 0 : size += hweight64(mask) * sizeof(u64);
7210 : }
7211 :
7212 0 : header->size += size;
7213 : }
7214 :
7215 0 : if (sample_type & PERF_SAMPLE_STACK_USER) {
7216 : /*
7217 : * Either we need PERF_SAMPLE_STACK_USER bit to be always
7218 : * processed as the last one or have additional check added
7219 : * in case new sample type is added, because we could eat
7220 : * up the rest of the sample size.
7221 : */
7222 0 : u16 stack_size = event->attr.sample_stack_user;
7223 0 : u16 size = sizeof(u64);
7224 :
7225 0 : stack_size = perf_sample_ustack_size(stack_size, header->size,
7226 : data->regs_user.regs);
7227 :
7228 : /*
7229 : * If there is something to dump, add space for the dump
7230 : * itself and for the field that tells the dynamic size,
7231 : * which is how many have been actually dumped.
7232 : */
7233 0 : if (stack_size)
7234 0 : size += sizeof(u64) + stack_size;
7235 :
7236 0 : data->stack_user_size = stack_size;
7237 0 : header->size += size;
7238 : }
7239 :
7240 0 : if (sample_type & PERF_SAMPLE_REGS_INTR) {
7241 : /* regs dump ABI info */
7242 0 : int size = sizeof(u64);
7243 :
7244 0 : perf_sample_regs_intr(&data->regs_intr, regs);
7245 :
7246 0 : if (data->regs_intr.regs) {
7247 0 : u64 mask = event->attr.sample_regs_intr;
7248 :
7249 0 : size += hweight64(mask) * sizeof(u64);
7250 : }
7251 :
7252 0 : header->size += size;
7253 : }
7254 :
7255 0 : if (sample_type & PERF_SAMPLE_PHYS_ADDR)
7256 0 : data->phys_addr = perf_virt_to_phys(data->addr);
7257 :
7258 : #ifdef CONFIG_CGROUP_PERF
7259 : if (sample_type & PERF_SAMPLE_CGROUP) {
7260 : struct cgroup *cgrp;
7261 :
7262 : /* protected by RCU */
7263 : cgrp = task_css_check(current, perf_event_cgrp_id, 1)->cgroup;
7264 : data->cgroup = cgroup_id(cgrp);
7265 : }
7266 : #endif
7267 :
7268 : /*
7269 : * PERF_DATA_PAGE_SIZE requires PERF_SAMPLE_ADDR. If the user doesn't
7270 : * require PERF_SAMPLE_ADDR, kernel implicitly retrieve the data->addr,
7271 : * but the value will not dump to the userspace.
7272 : */
7273 0 : if (sample_type & PERF_SAMPLE_DATA_PAGE_SIZE)
7274 0 : data->data_page_size = perf_get_page_size(data->addr);
7275 :
7276 0 : if (sample_type & PERF_SAMPLE_CODE_PAGE_SIZE)
7277 0 : data->code_page_size = perf_get_page_size(data->ip);
7278 :
7279 0 : if (sample_type & PERF_SAMPLE_AUX) {
7280 0 : u64 size;
7281 :
7282 0 : header->size += sizeof(u64); /* size */
7283 :
7284 : /*
7285 : * Given the 16bit nature of header::size, an AUX sample can
7286 : * easily overflow it, what with all the preceding sample bits.
7287 : * Make sure this doesn't happen by using up to U16_MAX bytes
7288 : * per sample in total (rounded down to 8 byte boundary).
7289 : */
7290 0 : size = min_t(size_t, U16_MAX - header->size,
7291 : event->attr.aux_sample_size);
7292 0 : size = rounddown(size, 8);
7293 0 : size = perf_prepare_sample_aux(event, data, size);
7294 :
7295 0 : WARN_ON_ONCE(size + header->size > U16_MAX);
7296 0 : header->size += size;
7297 : }
7298 : /*
7299 : * If you're adding more sample types here, you likely need to do
7300 : * something about the overflowing header::size, like repurpose the
7301 : * lowest 3 bits of size, which should be always zero at the moment.
7302 : * This raises a more important question, do we really need 512k sized
7303 : * samples and why, so good argumentation is in order for whatever you
7304 : * do here next.
7305 : */
7306 0 : WARN_ON_ONCE(header->size & 7);
7307 0 : }
7308 :
7309 : static __always_inline int
7310 0 : __perf_event_output(struct perf_event *event,
7311 : struct perf_sample_data *data,
7312 : struct pt_regs *regs,
7313 : int (*output_begin)(struct perf_output_handle *,
7314 : struct perf_sample_data *,
7315 : struct perf_event *,
7316 : unsigned int))
7317 : {
7318 0 : struct perf_output_handle handle;
7319 0 : struct perf_event_header header;
7320 0 : int err;
7321 :
7322 : /* protect the callchain buffers */
7323 0 : rcu_read_lock();
7324 :
7325 0 : perf_prepare_sample(&header, data, event, regs);
7326 :
7327 0 : err = output_begin(&handle, data, event, header.size);
7328 0 : if (err)
7329 0 : goto exit;
7330 :
7331 0 : perf_output_sample(&handle, &header, data, event);
7332 :
7333 0 : perf_output_end(&handle);
7334 :
7335 0 : exit:
7336 0 : rcu_read_unlock();
7337 0 : return err;
7338 : }
7339 :
7340 : void
7341 0 : perf_event_output_forward(struct perf_event *event,
7342 : struct perf_sample_data *data,
7343 : struct pt_regs *regs)
7344 : {
7345 0 : __perf_event_output(event, data, regs, perf_output_begin_forward);
7346 0 : }
7347 :
7348 : void
7349 0 : perf_event_output_backward(struct perf_event *event,
7350 : struct perf_sample_data *data,
7351 : struct pt_regs *regs)
7352 : {
7353 0 : __perf_event_output(event, data, regs, perf_output_begin_backward);
7354 0 : }
7355 :
7356 : int
7357 0 : perf_event_output(struct perf_event *event,
7358 : struct perf_sample_data *data,
7359 : struct pt_regs *regs)
7360 : {
7361 0 : return __perf_event_output(event, data, regs, perf_output_begin);
7362 : }
7363 :
7364 : /*
7365 : * read event_id
7366 : */
7367 :
7368 : struct perf_read_event {
7369 : struct perf_event_header header;
7370 :
7371 : u32 pid;
7372 : u32 tid;
7373 : };
7374 :
7375 : static void
7376 0 : perf_event_read_event(struct perf_event *event,
7377 : struct task_struct *task)
7378 : {
7379 0 : struct perf_output_handle handle;
7380 0 : struct perf_sample_data sample;
7381 0 : struct perf_read_event read_event = {
7382 : .header = {
7383 : .type = PERF_RECORD_READ,
7384 : .misc = 0,
7385 0 : .size = sizeof(read_event) + event->read_size,
7386 : },
7387 0 : .pid = perf_event_pid(event, task),
7388 0 : .tid = perf_event_tid(event, task),
7389 : };
7390 0 : int ret;
7391 :
7392 0 : perf_event_header__init_id(&read_event.header, &sample, event);
7393 0 : ret = perf_output_begin(&handle, &sample, event, read_event.header.size);
7394 0 : if (ret)
7395 0 : return;
7396 :
7397 0 : perf_output_put(&handle, read_event);
7398 0 : perf_output_read(&handle, event);
7399 0 : perf_event__output_id_sample(event, &handle, &sample);
7400 :
7401 0 : perf_output_end(&handle);
7402 : }
7403 :
7404 : typedef void (perf_iterate_f)(struct perf_event *event, void *data);
7405 :
7406 : static void
7407 0 : perf_iterate_ctx(struct perf_event_context *ctx,
7408 : perf_iterate_f output,
7409 : void *data, bool all)
7410 : {
7411 0 : struct perf_event *event;
7412 :
7413 0 : list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
7414 0 : if (!all) {
7415 0 : if (event->state < PERF_EVENT_STATE_INACTIVE)
7416 0 : continue;
7417 0 : if (!event_filter_match(event))
7418 0 : continue;
7419 : }
7420 :
7421 0 : output(event, data);
7422 : }
7423 0 : }
7424 :
7425 0 : static void perf_iterate_sb_cpu(perf_iterate_f output, void *data)
7426 : {
7427 0 : struct pmu_event_list *pel = this_cpu_ptr(&pmu_sb_events);
7428 0 : struct perf_event *event;
7429 :
7430 0 : list_for_each_entry_rcu(event, &pel->list, sb_list) {
7431 : /*
7432 : * Skip events that are not fully formed yet; ensure that
7433 : * if we observe event->ctx, both event and ctx will be
7434 : * complete enough. See perf_install_in_context().
7435 : */
7436 0 : if (!smp_load_acquire(&event->ctx))
7437 0 : continue;
7438 :
7439 0 : if (event->state < PERF_EVENT_STATE_INACTIVE)
7440 0 : continue;
7441 0 : if (!event_filter_match(event))
7442 0 : continue;
7443 0 : output(event, data);
7444 : }
7445 0 : }
7446 :
7447 : /*
7448 : * Iterate all events that need to receive side-band events.
7449 : *
7450 : * For new callers; ensure that account_pmu_sb_event() includes
7451 : * your event, otherwise it might not get delivered.
7452 : */
7453 : static void
7454 0 : perf_iterate_sb(perf_iterate_f output, void *data,
7455 : struct perf_event_context *task_ctx)
7456 : {
7457 0 : struct perf_event_context *ctx;
7458 0 : int ctxn;
7459 :
7460 0 : rcu_read_lock();
7461 0 : preempt_disable();
7462 :
7463 : /*
7464 : * If we have task_ctx != NULL we only notify the task context itself.
7465 : * The task_ctx is set only for EXIT events before releasing task
7466 : * context.
7467 : */
7468 0 : if (task_ctx) {
7469 0 : perf_iterate_ctx(task_ctx, output, data, false);
7470 0 : goto done;
7471 : }
7472 :
7473 0 : perf_iterate_sb_cpu(output, data);
7474 :
7475 0 : for_each_task_context_nr(ctxn) {
7476 0 : ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
7477 0 : if (ctx)
7478 0 : perf_iterate_ctx(ctx, output, data, false);
7479 : }
7480 0 : done:
7481 0 : preempt_enable();
7482 0 : rcu_read_unlock();
7483 0 : }
7484 :
7485 : /*
7486 : * Clear all file-based filters at exec, they'll have to be
7487 : * re-instated when/if these objects are mmapped again.
7488 : */
7489 0 : static void perf_event_addr_filters_exec(struct perf_event *event, void *data)
7490 : {
7491 0 : struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
7492 0 : struct perf_addr_filter *filter;
7493 0 : unsigned int restart = 0, count = 0;
7494 0 : unsigned long flags;
7495 :
7496 0 : if (!has_addr_filter(event))
7497 : return;
7498 :
7499 0 : raw_spin_lock_irqsave(&ifh->lock, flags);
7500 0 : list_for_each_entry(filter, &ifh->list, entry) {
7501 0 : if (filter->path.dentry) {
7502 0 : event->addr_filter_ranges[count].start = 0;
7503 0 : event->addr_filter_ranges[count].size = 0;
7504 0 : restart++;
7505 : }
7506 :
7507 0 : count++;
7508 : }
7509 :
7510 0 : if (restart)
7511 0 : event->addr_filters_gen++;
7512 0 : raw_spin_unlock_irqrestore(&ifh->lock, flags);
7513 :
7514 0 : if (restart)
7515 0 : perf_event_stop(event, 1);
7516 : }
7517 :
7518 870 : void perf_event_exec(void)
7519 : {
7520 870 : struct perf_event_context *ctx;
7521 870 : int ctxn;
7522 :
7523 870 : rcu_read_lock();
7524 2610 : for_each_task_context_nr(ctxn) {
7525 1740 : ctx = current->perf_event_ctxp[ctxn];
7526 1740 : if (!ctx)
7527 1740 : continue;
7528 :
7529 0 : perf_event_enable_on_exec(ctxn);
7530 :
7531 0 : perf_iterate_ctx(ctx, perf_event_addr_filters_exec, NULL,
7532 : true);
7533 : }
7534 870 : rcu_read_unlock();
7535 870 : }
7536 :
7537 : struct remote_output {
7538 : struct perf_buffer *rb;
7539 : int err;
7540 : };
7541 :
7542 0 : static void __perf_event_output_stop(struct perf_event *event, void *data)
7543 : {
7544 0 : struct perf_event *parent = event->parent;
7545 0 : struct remote_output *ro = data;
7546 0 : struct perf_buffer *rb = ro->rb;
7547 0 : struct stop_event_data sd = {
7548 : .event = event,
7549 : };
7550 :
7551 0 : if (!has_aux(event))
7552 0 : return;
7553 :
7554 0 : if (!parent)
7555 0 : parent = event;
7556 :
7557 : /*
7558 : * In case of inheritance, it will be the parent that links to the
7559 : * ring-buffer, but it will be the child that's actually using it.
7560 : *
7561 : * We are using event::rb to determine if the event should be stopped,
7562 : * however this may race with ring_buffer_attach() (through set_output),
7563 : * which will make us skip the event that actually needs to be stopped.
7564 : * So ring_buffer_attach() has to stop an aux event before re-assigning
7565 : * its rb pointer.
7566 : */
7567 0 : if (rcu_dereference(parent->rb) == rb)
7568 0 : ro->err = __perf_event_stop(&sd);
7569 : }
7570 :
7571 0 : static int __perf_pmu_output_stop(void *info)
7572 : {
7573 0 : struct perf_event *event = info;
7574 0 : struct pmu *pmu = event->ctx->pmu;
7575 0 : struct perf_cpu_context *cpuctx = this_cpu_ptr(pmu->pmu_cpu_context);
7576 0 : struct remote_output ro = {
7577 0 : .rb = event->rb,
7578 : };
7579 :
7580 0 : rcu_read_lock();
7581 0 : perf_iterate_ctx(&cpuctx->ctx, __perf_event_output_stop, &ro, false);
7582 0 : if (cpuctx->task_ctx)
7583 0 : perf_iterate_ctx(cpuctx->task_ctx, __perf_event_output_stop,
7584 : &ro, false);
7585 0 : rcu_read_unlock();
7586 :
7587 0 : return ro.err;
7588 : }
7589 :
7590 0 : static void perf_pmu_output_stop(struct perf_event *event)
7591 : {
7592 0 : struct perf_event *iter;
7593 0 : int err, cpu;
7594 :
7595 0 : restart:
7596 0 : rcu_read_lock();
7597 0 : list_for_each_entry_rcu(iter, &event->rb->event_list, rb_entry) {
7598 : /*
7599 : * For per-CPU events, we need to make sure that neither they
7600 : * nor their children are running; for cpu==-1 events it's
7601 : * sufficient to stop the event itself if it's active, since
7602 : * it can't have children.
7603 : */
7604 0 : cpu = iter->cpu;
7605 0 : if (cpu == -1)
7606 0 : cpu = READ_ONCE(iter->oncpu);
7607 :
7608 0 : if (cpu == -1)
7609 0 : continue;
7610 :
7611 0 : err = cpu_function_call(cpu, __perf_pmu_output_stop, event);
7612 0 : if (err == -EAGAIN) {
7613 0 : rcu_read_unlock();
7614 0 : goto restart;
7615 : }
7616 : }
7617 0 : rcu_read_unlock();
7618 0 : }
7619 :
7620 : /*
7621 : * task tracking -- fork/exit
7622 : *
7623 : * enabled by: attr.comm | attr.mmap | attr.mmap2 | attr.mmap_data | attr.task
7624 : */
7625 :
7626 : struct perf_task_event {
7627 : struct task_struct *task;
7628 : struct perf_event_context *task_ctx;
7629 :
7630 : struct {
7631 : struct perf_event_header header;
7632 :
7633 : u32 pid;
7634 : u32 ppid;
7635 : u32 tid;
7636 : u32 ptid;
7637 : u64 time;
7638 : } event_id;
7639 : };
7640 :
7641 0 : static int perf_event_task_match(struct perf_event *event)
7642 : {
7643 0 : return event->attr.comm || event->attr.mmap ||
7644 0 : event->attr.mmap2 || event->attr.mmap_data ||
7645 : event->attr.task;
7646 : }
7647 :
7648 0 : static void perf_event_task_output(struct perf_event *event,
7649 : void *data)
7650 : {
7651 0 : struct perf_task_event *task_event = data;
7652 0 : struct perf_output_handle handle;
7653 0 : struct perf_sample_data sample;
7654 0 : struct task_struct *task = task_event->task;
7655 0 : int ret, size = task_event->event_id.header.size;
7656 :
7657 0 : if (!perf_event_task_match(event))
7658 0 : return;
7659 :
7660 0 : perf_event_header__init_id(&task_event->event_id.header, &sample, event);
7661 :
7662 0 : ret = perf_output_begin(&handle, &sample, event,
7663 0 : task_event->event_id.header.size);
7664 0 : if (ret)
7665 0 : goto out;
7666 :
7667 0 : task_event->event_id.pid = perf_event_pid(event, task);
7668 0 : task_event->event_id.tid = perf_event_tid(event, task);
7669 :
7670 0 : if (task_event->event_id.header.type == PERF_RECORD_EXIT) {
7671 0 : task_event->event_id.ppid = perf_event_pid(event,
7672 : task->real_parent);
7673 0 : task_event->event_id.ptid = perf_event_pid(event,
7674 : task->real_parent);
7675 : } else { /* PERF_RECORD_FORK */
7676 0 : task_event->event_id.ppid = perf_event_pid(event, current);
7677 0 : task_event->event_id.ptid = perf_event_tid(event, current);
7678 : }
7679 :
7680 0 : task_event->event_id.time = perf_event_clock(event);
7681 :
7682 0 : perf_output_put(&handle, task_event->event_id);
7683 :
7684 0 : perf_event__output_id_sample(event, &handle, &sample);
7685 :
7686 0 : perf_output_end(&handle);
7687 0 : out:
7688 0 : task_event->event_id.header.size = size;
7689 : }
7690 :
7691 2389 : static void perf_event_task(struct task_struct *task,
7692 : struct perf_event_context *task_ctx,
7693 : int new)
7694 : {
7695 2389 : struct perf_task_event task_event;
7696 :
7697 2389 : if (!atomic_read(&nr_comm_events) &&
7698 2389 : !atomic_read(&nr_mmap_events) &&
7699 2389 : !atomic_read(&nr_task_events))
7700 2389 : return;
7701 :
7702 0 : task_event = (struct perf_task_event){
7703 : .task = task,
7704 : .task_ctx = task_ctx,
7705 : .event_id = {
7706 : .header = {
7707 0 : .type = new ? PERF_RECORD_FORK : PERF_RECORD_EXIT,
7708 : .misc = 0,
7709 : .size = sizeof(task_event.event_id),
7710 : },
7711 : /* .pid */
7712 : /* .ppid */
7713 : /* .tid */
7714 : /* .ptid */
7715 : /* .time */
7716 : },
7717 : };
7718 :
7719 0 : perf_iterate_sb(perf_event_task_output,
7720 : &task_event,
7721 : task_ctx);
7722 : }
7723 :
7724 1234 : void perf_event_fork(struct task_struct *task)
7725 : {
7726 1234 : perf_event_task(task, NULL, 1);
7727 1234 : perf_event_namespaces(task);
7728 1234 : }
7729 :
7730 : /*
7731 : * comm tracking
7732 : */
7733 :
7734 : struct perf_comm_event {
7735 : struct task_struct *task;
7736 : char *comm;
7737 : int comm_size;
7738 :
7739 : struct {
7740 : struct perf_event_header header;
7741 :
7742 : u32 pid;
7743 : u32 tid;
7744 : } event_id;
7745 : };
7746 :
7747 0 : static int perf_event_comm_match(struct perf_event *event)
7748 : {
7749 0 : return event->attr.comm;
7750 : }
7751 :
7752 0 : static void perf_event_comm_output(struct perf_event *event,
7753 : void *data)
7754 : {
7755 0 : struct perf_comm_event *comm_event = data;
7756 0 : struct perf_output_handle handle;
7757 0 : struct perf_sample_data sample;
7758 0 : int size = comm_event->event_id.header.size;
7759 0 : int ret;
7760 :
7761 0 : if (!perf_event_comm_match(event))
7762 0 : return;
7763 :
7764 0 : perf_event_header__init_id(&comm_event->event_id.header, &sample, event);
7765 0 : ret = perf_output_begin(&handle, &sample, event,
7766 0 : comm_event->event_id.header.size);
7767 :
7768 0 : if (ret)
7769 0 : goto out;
7770 :
7771 0 : comm_event->event_id.pid = perf_event_pid(event, comm_event->task);
7772 0 : comm_event->event_id.tid = perf_event_tid(event, comm_event->task);
7773 :
7774 0 : perf_output_put(&handle, comm_event->event_id);
7775 0 : __output_copy(&handle, comm_event->comm,
7776 0 : comm_event->comm_size);
7777 :
7778 0 : perf_event__output_id_sample(event, &handle, &sample);
7779 :
7780 0 : perf_output_end(&handle);
7781 0 : out:
7782 0 : comm_event->event_id.header.size = size;
7783 : }
7784 :
7785 0 : static void perf_event_comm_event(struct perf_comm_event *comm_event)
7786 : {
7787 0 : char comm[TASK_COMM_LEN];
7788 0 : unsigned int size;
7789 :
7790 0 : memset(comm, 0, sizeof(comm));
7791 0 : strlcpy(comm, comm_event->task->comm, sizeof(comm));
7792 0 : size = ALIGN(strlen(comm)+1, sizeof(u64));
7793 :
7794 0 : comm_event->comm = comm;
7795 0 : comm_event->comm_size = size;
7796 :
7797 0 : comm_event->event_id.header.size = sizeof(comm_event->event_id) + size;
7798 :
7799 0 : perf_iterate_sb(perf_event_comm_output,
7800 : comm_event,
7801 : NULL);
7802 0 : }
7803 :
7804 995 : void perf_event_comm(struct task_struct *task, bool exec)
7805 : {
7806 995 : struct perf_comm_event comm_event;
7807 :
7808 995 : if (!atomic_read(&nr_comm_events))
7809 995 : return;
7810 :
7811 0 : comm_event = (struct perf_comm_event){
7812 : .task = task,
7813 : /* .comm */
7814 : /* .comm_size */
7815 : .event_id = {
7816 : .header = {
7817 : .type = PERF_RECORD_COMM,
7818 : .misc = exec ? PERF_RECORD_MISC_COMM_EXEC : 0,
7819 : /* .size */
7820 : },
7821 : /* .pid */
7822 : /* .tid */
7823 : },
7824 : };
7825 :
7826 0 : perf_event_comm_event(&comm_event);
7827 : }
7828 :
7829 : /*
7830 : * namespaces tracking
7831 : */
7832 :
7833 : struct perf_namespaces_event {
7834 : struct task_struct *task;
7835 :
7836 : struct {
7837 : struct perf_event_header header;
7838 :
7839 : u32 pid;
7840 : u32 tid;
7841 : u64 nr_namespaces;
7842 : struct perf_ns_link_info link_info[NR_NAMESPACES];
7843 : } event_id;
7844 : };
7845 :
7846 0 : static int perf_event_namespaces_match(struct perf_event *event)
7847 : {
7848 0 : return event->attr.namespaces;
7849 : }
7850 :
7851 0 : static void perf_event_namespaces_output(struct perf_event *event,
7852 : void *data)
7853 : {
7854 0 : struct perf_namespaces_event *namespaces_event = data;
7855 0 : struct perf_output_handle handle;
7856 0 : struct perf_sample_data sample;
7857 0 : u16 header_size = namespaces_event->event_id.header.size;
7858 0 : int ret;
7859 :
7860 0 : if (!perf_event_namespaces_match(event))
7861 0 : return;
7862 :
7863 0 : perf_event_header__init_id(&namespaces_event->event_id.header,
7864 : &sample, event);
7865 0 : ret = perf_output_begin(&handle, &sample, event,
7866 0 : namespaces_event->event_id.header.size);
7867 0 : if (ret)
7868 0 : goto out;
7869 :
7870 0 : namespaces_event->event_id.pid = perf_event_pid(event,
7871 : namespaces_event->task);
7872 0 : namespaces_event->event_id.tid = perf_event_tid(event,
7873 : namespaces_event->task);
7874 :
7875 0 : perf_output_put(&handle, namespaces_event->event_id);
7876 :
7877 0 : perf_event__output_id_sample(event, &handle, &sample);
7878 :
7879 0 : perf_output_end(&handle);
7880 0 : out:
7881 0 : namespaces_event->event_id.header.size = header_size;
7882 : }
7883 :
7884 0 : static void perf_fill_ns_link_info(struct perf_ns_link_info *ns_link_info,
7885 : struct task_struct *task,
7886 : const struct proc_ns_operations *ns_ops)
7887 : {
7888 0 : struct path ns_path;
7889 0 : struct inode *ns_inode;
7890 0 : int error;
7891 :
7892 0 : error = ns_get_path(&ns_path, task, ns_ops);
7893 0 : if (!error) {
7894 0 : ns_inode = ns_path.dentry->d_inode;
7895 0 : ns_link_info->dev = new_encode_dev(ns_inode->i_sb->s_dev);
7896 0 : ns_link_info->ino = ns_inode->i_ino;
7897 0 : path_put(&ns_path);
7898 : }
7899 0 : }
7900 :
7901 1284 : void perf_event_namespaces(struct task_struct *task)
7902 : {
7903 1284 : struct perf_namespaces_event namespaces_event;
7904 1284 : struct perf_ns_link_info *ns_link_info;
7905 :
7906 1284 : if (!atomic_read(&nr_namespaces_events))
7907 1284 : return;
7908 :
7909 0 : namespaces_event = (struct perf_namespaces_event){
7910 : .task = task,
7911 : .event_id = {
7912 : .header = {
7913 : .type = PERF_RECORD_NAMESPACES,
7914 : .misc = 0,
7915 : .size = sizeof(namespaces_event.event_id),
7916 : },
7917 : /* .pid */
7918 : /* .tid */
7919 : .nr_namespaces = NR_NAMESPACES,
7920 : /* .link_info[NR_NAMESPACES] */
7921 : },
7922 : };
7923 :
7924 0 : ns_link_info = namespaces_event.event_id.link_info;
7925 :
7926 0 : perf_fill_ns_link_info(&ns_link_info[MNT_NS_INDEX],
7927 : task, &mntns_operations);
7928 :
7929 : #ifdef CONFIG_USER_NS
7930 : perf_fill_ns_link_info(&ns_link_info[USER_NS_INDEX],
7931 : task, &userns_operations);
7932 : #endif
7933 : #ifdef CONFIG_NET_NS
7934 : perf_fill_ns_link_info(&ns_link_info[NET_NS_INDEX],
7935 : task, &netns_operations);
7936 : #endif
7937 : #ifdef CONFIG_UTS_NS
7938 : perf_fill_ns_link_info(&ns_link_info[UTS_NS_INDEX],
7939 : task, &utsns_operations);
7940 : #endif
7941 : #ifdef CONFIG_IPC_NS
7942 : perf_fill_ns_link_info(&ns_link_info[IPC_NS_INDEX],
7943 : task, &ipcns_operations);
7944 : #endif
7945 : #ifdef CONFIG_PID_NS
7946 : perf_fill_ns_link_info(&ns_link_info[PID_NS_INDEX],
7947 : task, &pidns_operations);
7948 : #endif
7949 : #ifdef CONFIG_CGROUPS
7950 0 : perf_fill_ns_link_info(&ns_link_info[CGROUP_NS_INDEX],
7951 : task, &cgroupns_operations);
7952 : #endif
7953 :
7954 0 : perf_iterate_sb(perf_event_namespaces_output,
7955 : &namespaces_event,
7956 : NULL);
7957 : }
7958 :
7959 : /*
7960 : * cgroup tracking
7961 : */
7962 : #ifdef CONFIG_CGROUP_PERF
7963 :
7964 : struct perf_cgroup_event {
7965 : char *path;
7966 : int path_size;
7967 : struct {
7968 : struct perf_event_header header;
7969 : u64 id;
7970 : char path[];
7971 : } event_id;
7972 : };
7973 :
7974 : static int perf_event_cgroup_match(struct perf_event *event)
7975 : {
7976 : return event->attr.cgroup;
7977 : }
7978 :
7979 : static void perf_event_cgroup_output(struct perf_event *event, void *data)
7980 : {
7981 : struct perf_cgroup_event *cgroup_event = data;
7982 : struct perf_output_handle handle;
7983 : struct perf_sample_data sample;
7984 : u16 header_size = cgroup_event->event_id.header.size;
7985 : int ret;
7986 :
7987 : if (!perf_event_cgroup_match(event))
7988 : return;
7989 :
7990 : perf_event_header__init_id(&cgroup_event->event_id.header,
7991 : &sample, event);
7992 : ret = perf_output_begin(&handle, &sample, event,
7993 : cgroup_event->event_id.header.size);
7994 : if (ret)
7995 : goto out;
7996 :
7997 : perf_output_put(&handle, cgroup_event->event_id);
7998 : __output_copy(&handle, cgroup_event->path, cgroup_event->path_size);
7999 :
8000 : perf_event__output_id_sample(event, &handle, &sample);
8001 :
8002 : perf_output_end(&handle);
8003 : out:
8004 : cgroup_event->event_id.header.size = header_size;
8005 : }
8006 :
8007 : static void perf_event_cgroup(struct cgroup *cgrp)
8008 : {
8009 : struct perf_cgroup_event cgroup_event;
8010 : char path_enomem[16] = "//enomem";
8011 : char *pathname;
8012 : size_t size;
8013 :
8014 : if (!atomic_read(&nr_cgroup_events))
8015 : return;
8016 :
8017 : cgroup_event = (struct perf_cgroup_event){
8018 : .event_id = {
8019 : .header = {
8020 : .type = PERF_RECORD_CGROUP,
8021 : .misc = 0,
8022 : .size = sizeof(cgroup_event.event_id),
8023 : },
8024 : .id = cgroup_id(cgrp),
8025 : },
8026 : };
8027 :
8028 : pathname = kmalloc(PATH_MAX, GFP_KERNEL);
8029 : if (pathname == NULL) {
8030 : cgroup_event.path = path_enomem;
8031 : } else {
8032 : /* just to be sure to have enough space for alignment */
8033 : cgroup_path(cgrp, pathname, PATH_MAX - sizeof(u64));
8034 : cgroup_event.path = pathname;
8035 : }
8036 :
8037 : /*
8038 : * Since our buffer works in 8 byte units we need to align our string
8039 : * size to a multiple of 8. However, we must guarantee the tail end is
8040 : * zero'd out to avoid leaking random bits to userspace.
8041 : */
8042 : size = strlen(cgroup_event.path) + 1;
8043 : while (!IS_ALIGNED(size, sizeof(u64)))
8044 : cgroup_event.path[size++] = '\0';
8045 :
8046 : cgroup_event.event_id.header.size += size;
8047 : cgroup_event.path_size = size;
8048 :
8049 : perf_iterate_sb(perf_event_cgroup_output,
8050 : &cgroup_event,
8051 : NULL);
8052 :
8053 : kfree(pathname);
8054 : }
8055 :
8056 : #endif
8057 :
8058 : /*
8059 : * mmap tracking
8060 : */
8061 :
8062 : struct perf_mmap_event {
8063 : struct vm_area_struct *vma;
8064 :
8065 : const char *file_name;
8066 : int file_size;
8067 : int maj, min;
8068 : u64 ino;
8069 : u64 ino_generation;
8070 : u32 prot, flags;
8071 : u8 build_id[BUILD_ID_SIZE_MAX];
8072 : u32 build_id_size;
8073 :
8074 : struct {
8075 : struct perf_event_header header;
8076 :
8077 : u32 pid;
8078 : u32 tid;
8079 : u64 start;
8080 : u64 len;
8081 : u64 pgoff;
8082 : } event_id;
8083 : };
8084 :
8085 0 : static int perf_event_mmap_match(struct perf_event *event,
8086 : void *data)
8087 : {
8088 0 : struct perf_mmap_event *mmap_event = data;
8089 0 : struct vm_area_struct *vma = mmap_event->vma;
8090 0 : int executable = vma->vm_flags & VM_EXEC;
8091 :
8092 0 : return (!executable && event->attr.mmap_data) ||
8093 0 : (executable && (event->attr.mmap || event->attr.mmap2));
8094 : }
8095 :
8096 0 : static void perf_event_mmap_output(struct perf_event *event,
8097 : void *data)
8098 : {
8099 0 : struct perf_mmap_event *mmap_event = data;
8100 0 : struct perf_output_handle handle;
8101 0 : struct perf_sample_data sample;
8102 0 : int size = mmap_event->event_id.header.size;
8103 0 : u32 type = mmap_event->event_id.header.type;
8104 0 : bool use_build_id;
8105 0 : int ret;
8106 :
8107 0 : if (!perf_event_mmap_match(event, data))
8108 0 : return;
8109 :
8110 0 : if (event->attr.mmap2) {
8111 0 : mmap_event->event_id.header.type = PERF_RECORD_MMAP2;
8112 0 : mmap_event->event_id.header.size += sizeof(mmap_event->maj);
8113 0 : mmap_event->event_id.header.size += sizeof(mmap_event->min);
8114 0 : mmap_event->event_id.header.size += sizeof(mmap_event->ino);
8115 0 : mmap_event->event_id.header.size += sizeof(mmap_event->ino_generation);
8116 0 : mmap_event->event_id.header.size += sizeof(mmap_event->prot);
8117 0 : mmap_event->event_id.header.size += sizeof(mmap_event->flags);
8118 : }
8119 :
8120 0 : perf_event_header__init_id(&mmap_event->event_id.header, &sample, event);
8121 0 : ret = perf_output_begin(&handle, &sample, event,
8122 0 : mmap_event->event_id.header.size);
8123 0 : if (ret)
8124 0 : goto out;
8125 :
8126 0 : mmap_event->event_id.pid = perf_event_pid(event, current);
8127 0 : mmap_event->event_id.tid = perf_event_tid(event, current);
8128 :
8129 0 : use_build_id = event->attr.build_id && mmap_event->build_id_size;
8130 :
8131 0 : if (event->attr.mmap2 && use_build_id)
8132 0 : mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_BUILD_ID;
8133 :
8134 0 : perf_output_put(&handle, mmap_event->event_id);
8135 :
8136 0 : if (event->attr.mmap2) {
8137 0 : if (use_build_id) {
8138 0 : u8 size[4] = { (u8) mmap_event->build_id_size, 0, 0, 0 };
8139 :
8140 0 : __output_copy(&handle, size, 4);
8141 0 : __output_copy(&handle, mmap_event->build_id, BUILD_ID_SIZE_MAX);
8142 : } else {
8143 0 : perf_output_put(&handle, mmap_event->maj);
8144 0 : perf_output_put(&handle, mmap_event->min);
8145 0 : perf_output_put(&handle, mmap_event->ino);
8146 0 : perf_output_put(&handle, mmap_event->ino_generation);
8147 : }
8148 0 : perf_output_put(&handle, mmap_event->prot);
8149 0 : perf_output_put(&handle, mmap_event->flags);
8150 : }
8151 :
8152 0 : __output_copy(&handle, mmap_event->file_name,
8153 0 : mmap_event->file_size);
8154 :
8155 0 : perf_event__output_id_sample(event, &handle, &sample);
8156 :
8157 0 : perf_output_end(&handle);
8158 0 : out:
8159 0 : mmap_event->event_id.header.size = size;
8160 0 : mmap_event->event_id.header.type = type;
8161 : }
8162 :
8163 0 : static void perf_event_mmap_event(struct perf_mmap_event *mmap_event)
8164 : {
8165 0 : struct vm_area_struct *vma = mmap_event->vma;
8166 0 : struct file *file = vma->vm_file;
8167 0 : int maj = 0, min = 0;
8168 0 : u64 ino = 0, gen = 0;
8169 0 : u32 prot = 0, flags = 0;
8170 0 : unsigned int size;
8171 0 : char tmp[16];
8172 0 : char *buf = NULL;
8173 0 : char *name;
8174 :
8175 0 : if (vma->vm_flags & VM_READ)
8176 : prot |= PROT_READ;
8177 0 : if (vma->vm_flags & VM_WRITE)
8178 0 : prot |= PROT_WRITE;
8179 0 : if (vma->vm_flags & VM_EXEC)
8180 0 : prot |= PROT_EXEC;
8181 :
8182 0 : if (vma->vm_flags & VM_MAYSHARE)
8183 : flags = MAP_SHARED;
8184 : else
8185 0 : flags = MAP_PRIVATE;
8186 :
8187 0 : if (vma->vm_flags & VM_DENYWRITE)
8188 0 : flags |= MAP_DENYWRITE;
8189 0 : if (vma->vm_flags & VM_MAYEXEC)
8190 0 : flags |= MAP_EXECUTABLE;
8191 0 : if (vma->vm_flags & VM_LOCKED)
8192 0 : flags |= MAP_LOCKED;
8193 0 : if (is_vm_hugetlb_page(vma))
8194 : flags |= MAP_HUGETLB;
8195 :
8196 0 : if (file) {
8197 0 : struct inode *inode;
8198 0 : dev_t dev;
8199 :
8200 0 : buf = kmalloc(PATH_MAX, GFP_KERNEL);
8201 0 : if (!buf) {
8202 0 : name = "//enomem";
8203 0 : goto cpy_name;
8204 : }
8205 : /*
8206 : * d_path() works from the end of the rb backwards, so we
8207 : * need to add enough zero bytes after the string to handle
8208 : * the 64bit alignment we do later.
8209 : */
8210 0 : name = file_path(file, buf, PATH_MAX - sizeof(u64));
8211 0 : if (IS_ERR(name)) {
8212 0 : name = "//toolong";
8213 0 : goto cpy_name;
8214 : }
8215 0 : inode = file_inode(vma->vm_file);
8216 0 : dev = inode->i_sb->s_dev;
8217 0 : ino = inode->i_ino;
8218 0 : gen = inode->i_generation;
8219 0 : maj = MAJOR(dev);
8220 0 : min = MINOR(dev);
8221 :
8222 0 : goto got_name;
8223 : } else {
8224 0 : if (vma->vm_ops && vma->vm_ops->name) {
8225 0 : name = (char *) vma->vm_ops->name(vma);
8226 0 : if (name)
8227 0 : goto cpy_name;
8228 : }
8229 :
8230 0 : name = (char *)arch_vma_name(vma);
8231 0 : if (name)
8232 0 : goto cpy_name;
8233 :
8234 0 : if (vma->vm_start <= vma->vm_mm->start_brk &&
8235 0 : vma->vm_end >= vma->vm_mm->brk) {
8236 0 : name = "[heap]";
8237 0 : goto cpy_name;
8238 : }
8239 0 : if (vma->vm_start <= vma->vm_mm->start_stack &&
8240 0 : vma->vm_end >= vma->vm_mm->start_stack) {
8241 0 : name = "[stack]";
8242 0 : goto cpy_name;
8243 : }
8244 :
8245 0 : name = "//anon";
8246 0 : goto cpy_name;
8247 : }
8248 :
8249 0 : cpy_name:
8250 0 : strlcpy(tmp, name, sizeof(tmp));
8251 0 : name = tmp;
8252 0 : got_name:
8253 : /*
8254 : * Since our buffer works in 8 byte units we need to align our string
8255 : * size to a multiple of 8. However, we must guarantee the tail end is
8256 : * zero'd out to avoid leaking random bits to userspace.
8257 : */
8258 0 : size = strlen(name)+1;
8259 0 : while (!IS_ALIGNED(size, sizeof(u64)))
8260 0 : name[size++] = '\0';
8261 :
8262 0 : mmap_event->file_name = name;
8263 0 : mmap_event->file_size = size;
8264 0 : mmap_event->maj = maj;
8265 0 : mmap_event->min = min;
8266 0 : mmap_event->ino = ino;
8267 0 : mmap_event->ino_generation = gen;
8268 0 : mmap_event->prot = prot;
8269 0 : mmap_event->flags = flags;
8270 :
8271 0 : if (!(vma->vm_flags & VM_EXEC))
8272 0 : mmap_event->event_id.header.misc |= PERF_RECORD_MISC_MMAP_DATA;
8273 :
8274 0 : mmap_event->event_id.header.size = sizeof(mmap_event->event_id) + size;
8275 :
8276 0 : if (atomic_read(&nr_build_id_events))
8277 0 : build_id_parse(vma, mmap_event->build_id, &mmap_event->build_id_size);
8278 :
8279 0 : perf_iterate_sb(perf_event_mmap_output,
8280 : mmap_event,
8281 : NULL);
8282 :
8283 0 : kfree(buf);
8284 0 : }
8285 :
8286 : /*
8287 : * Check whether inode and address range match filter criteria.
8288 : */
8289 0 : static bool perf_addr_filter_match(struct perf_addr_filter *filter,
8290 : struct file *file, unsigned long offset,
8291 : unsigned long size)
8292 : {
8293 : /* d_inode(NULL) won't be equal to any mapped user-space file */
8294 0 : if (!filter->path.dentry)
8295 : return false;
8296 :
8297 0 : if (d_inode(filter->path.dentry) != file_inode(file))
8298 : return false;
8299 :
8300 0 : if (filter->offset > offset + size)
8301 : return false;
8302 :
8303 0 : if (filter->offset + filter->size < offset)
8304 0 : return false;
8305 :
8306 : return true;
8307 : }
8308 :
8309 0 : static bool perf_addr_filter_vma_adjust(struct perf_addr_filter *filter,
8310 : struct vm_area_struct *vma,
8311 : struct perf_addr_filter_range *fr)
8312 : {
8313 0 : unsigned long vma_size = vma->vm_end - vma->vm_start;
8314 0 : unsigned long off = vma->vm_pgoff << PAGE_SHIFT;
8315 0 : struct file *file = vma->vm_file;
8316 :
8317 0 : if (!perf_addr_filter_match(filter, file, off, vma_size))
8318 : return false;
8319 :
8320 0 : if (filter->offset < off) {
8321 0 : fr->start = vma->vm_start;
8322 0 : fr->size = min(vma_size, filter->size - (off - filter->offset));
8323 : } else {
8324 0 : fr->start = vma->vm_start + filter->offset - off;
8325 0 : fr->size = min(vma->vm_end - fr->start, filter->size);
8326 : }
8327 :
8328 : return true;
8329 : }
8330 :
8331 0 : static void __perf_addr_filters_adjust(struct perf_event *event, void *data)
8332 : {
8333 0 : struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
8334 0 : struct vm_area_struct *vma = data;
8335 0 : struct perf_addr_filter *filter;
8336 0 : unsigned int restart = 0, count = 0;
8337 0 : unsigned long flags;
8338 :
8339 0 : if (!has_addr_filter(event))
8340 : return;
8341 :
8342 0 : if (!vma->vm_file)
8343 : return;
8344 :
8345 0 : raw_spin_lock_irqsave(&ifh->lock, flags);
8346 0 : list_for_each_entry(filter, &ifh->list, entry) {
8347 0 : if (perf_addr_filter_vma_adjust(filter, vma,
8348 0 : &event->addr_filter_ranges[count]))
8349 0 : restart++;
8350 :
8351 0 : count++;
8352 : }
8353 :
8354 0 : if (restart)
8355 0 : event->addr_filters_gen++;
8356 0 : raw_spin_unlock_irqrestore(&ifh->lock, flags);
8357 :
8358 0 : if (restart)
8359 0 : perf_event_stop(event, 1);
8360 : }
8361 :
8362 : /*
8363 : * Adjust all task's events' filters to the new vma
8364 : */
8365 0 : static void perf_addr_filters_adjust(struct vm_area_struct *vma)
8366 : {
8367 0 : struct perf_event_context *ctx;
8368 0 : int ctxn;
8369 :
8370 : /*
8371 : * Data tracing isn't supported yet and as such there is no need
8372 : * to keep track of anything that isn't related to executable code:
8373 : */
8374 0 : if (!(vma->vm_flags & VM_EXEC))
8375 : return;
8376 :
8377 0 : rcu_read_lock();
8378 0 : for_each_task_context_nr(ctxn) {
8379 0 : ctx = rcu_dereference(current->perf_event_ctxp[ctxn]);
8380 0 : if (!ctx)
8381 0 : continue;
8382 :
8383 0 : perf_iterate_ctx(ctx, __perf_addr_filters_adjust, vma, true);
8384 : }
8385 0 : rcu_read_unlock();
8386 : }
8387 :
8388 40323 : void perf_event_mmap(struct vm_area_struct *vma)
8389 : {
8390 40323 : struct perf_mmap_event mmap_event;
8391 :
8392 40323 : if (!atomic_read(&nr_mmap_events))
8393 40322 : return;
8394 :
8395 0 : mmap_event = (struct perf_mmap_event){
8396 : .vma = vma,
8397 : /* .file_name */
8398 : /* .file_size */
8399 : .event_id = {
8400 : .header = {
8401 : .type = PERF_RECORD_MMAP,
8402 : .misc = PERF_RECORD_MISC_USER,
8403 : /* .size */
8404 : },
8405 : /* .pid */
8406 : /* .tid */
8407 0 : .start = vma->vm_start,
8408 0 : .len = vma->vm_end - vma->vm_start,
8409 0 : .pgoff = (u64)vma->vm_pgoff << PAGE_SHIFT,
8410 : },
8411 : /* .maj (attr_mmap2 only) */
8412 : /* .min (attr_mmap2 only) */
8413 : /* .ino (attr_mmap2 only) */
8414 : /* .ino_generation (attr_mmap2 only) */
8415 : /* .prot (attr_mmap2 only) */
8416 : /* .flags (attr_mmap2 only) */
8417 : };
8418 :
8419 0 : perf_addr_filters_adjust(vma);
8420 0 : perf_event_mmap_event(&mmap_event);
8421 : }
8422 :
8423 0 : void perf_event_aux_event(struct perf_event *event, unsigned long head,
8424 : unsigned long size, u64 flags)
8425 : {
8426 0 : struct perf_output_handle handle;
8427 0 : struct perf_sample_data sample;
8428 0 : struct perf_aux_event {
8429 : struct perf_event_header header;
8430 : u64 offset;
8431 : u64 size;
8432 : u64 flags;
8433 0 : } rec = {
8434 : .header = {
8435 : .type = PERF_RECORD_AUX,
8436 : .misc = 0,
8437 : .size = sizeof(rec),
8438 : },
8439 : .offset = head,
8440 : .size = size,
8441 : .flags = flags,
8442 : };
8443 0 : int ret;
8444 :
8445 0 : perf_event_header__init_id(&rec.header, &sample, event);
8446 0 : ret = perf_output_begin(&handle, &sample, event, rec.header.size);
8447 :
8448 0 : if (ret)
8449 0 : return;
8450 :
8451 0 : perf_output_put(&handle, rec);
8452 0 : perf_event__output_id_sample(event, &handle, &sample);
8453 :
8454 0 : perf_output_end(&handle);
8455 : }
8456 :
8457 : /*
8458 : * Lost/dropped samples logging
8459 : */
8460 0 : void perf_log_lost_samples(struct perf_event *event, u64 lost)
8461 : {
8462 0 : struct perf_output_handle handle;
8463 0 : struct perf_sample_data sample;
8464 0 : int ret;
8465 :
8466 0 : struct {
8467 : struct perf_event_header header;
8468 : u64 lost;
8469 0 : } lost_samples_event = {
8470 : .header = {
8471 : .type = PERF_RECORD_LOST_SAMPLES,
8472 : .misc = 0,
8473 : .size = sizeof(lost_samples_event),
8474 : },
8475 : .lost = lost,
8476 : };
8477 :
8478 0 : perf_event_header__init_id(&lost_samples_event.header, &sample, event);
8479 :
8480 0 : ret = perf_output_begin(&handle, &sample, event,
8481 0 : lost_samples_event.header.size);
8482 0 : if (ret)
8483 0 : return;
8484 :
8485 0 : perf_output_put(&handle, lost_samples_event);
8486 0 : perf_event__output_id_sample(event, &handle, &sample);
8487 0 : perf_output_end(&handle);
8488 : }
8489 :
8490 : /*
8491 : * context_switch tracking
8492 : */
8493 :
8494 : struct perf_switch_event {
8495 : struct task_struct *task;
8496 : struct task_struct *next_prev;
8497 :
8498 : struct {
8499 : struct perf_event_header header;
8500 : u32 next_prev_pid;
8501 : u32 next_prev_tid;
8502 : } event_id;
8503 : };
8504 :
8505 0 : static int perf_event_switch_match(struct perf_event *event)
8506 : {
8507 0 : return event->attr.context_switch;
8508 : }
8509 :
8510 0 : static void perf_event_switch_output(struct perf_event *event, void *data)
8511 : {
8512 0 : struct perf_switch_event *se = data;
8513 0 : struct perf_output_handle handle;
8514 0 : struct perf_sample_data sample;
8515 0 : int ret;
8516 :
8517 0 : if (!perf_event_switch_match(event))
8518 0 : return;
8519 :
8520 : /* Only CPU-wide events are allowed to see next/prev pid/tid */
8521 0 : if (event->ctx->task) {
8522 0 : se->event_id.header.type = PERF_RECORD_SWITCH;
8523 0 : se->event_id.header.size = sizeof(se->event_id.header);
8524 : } else {
8525 0 : se->event_id.header.type = PERF_RECORD_SWITCH_CPU_WIDE;
8526 0 : se->event_id.header.size = sizeof(se->event_id);
8527 0 : se->event_id.next_prev_pid =
8528 0 : perf_event_pid(event, se->next_prev);
8529 0 : se->event_id.next_prev_tid =
8530 0 : perf_event_tid(event, se->next_prev);
8531 : }
8532 :
8533 0 : perf_event_header__init_id(&se->event_id.header, &sample, event);
8534 :
8535 0 : ret = perf_output_begin(&handle, &sample, event, se->event_id.header.size);
8536 0 : if (ret)
8537 : return;
8538 :
8539 0 : if (event->ctx->task)
8540 0 : perf_output_put(&handle, se->event_id.header);
8541 : else
8542 0 : perf_output_put(&handle, se->event_id);
8543 :
8544 0 : perf_event__output_id_sample(event, &handle, &sample);
8545 :
8546 0 : perf_output_end(&handle);
8547 : }
8548 :
8549 0 : static void perf_event_switch(struct task_struct *task,
8550 : struct task_struct *next_prev, bool sched_in)
8551 : {
8552 0 : struct perf_switch_event switch_event;
8553 :
8554 : /* N.B. caller checks nr_switch_events != 0 */
8555 :
8556 0 : switch_event = (struct perf_switch_event){
8557 : .task = task,
8558 : .next_prev = next_prev,
8559 : .event_id = {
8560 : .header = {
8561 : /* .type */
8562 : .misc = sched_in ? 0 : PERF_RECORD_MISC_SWITCH_OUT,
8563 : /* .size */
8564 : },
8565 : /* .next_prev_pid */
8566 : /* .next_prev_tid */
8567 : },
8568 : };
8569 :
8570 0 : if (!sched_in && task->state == TASK_RUNNING)
8571 0 : switch_event.event_id.header.misc |=
8572 : PERF_RECORD_MISC_SWITCH_OUT_PREEMPT;
8573 :
8574 0 : perf_iterate_sb(perf_event_switch_output,
8575 : &switch_event,
8576 : NULL);
8577 0 : }
8578 :
8579 : /*
8580 : * IRQ throttle logging
8581 : */
8582 :
8583 0 : static void perf_log_throttle(struct perf_event *event, int enable)
8584 : {
8585 0 : struct perf_output_handle handle;
8586 0 : struct perf_sample_data sample;
8587 0 : int ret;
8588 :
8589 0 : struct {
8590 : struct perf_event_header header;
8591 : u64 time;
8592 : u64 id;
8593 : u64 stream_id;
8594 0 : } throttle_event = {
8595 : .header = {
8596 : .type = PERF_RECORD_THROTTLE,
8597 : .misc = 0,
8598 : .size = sizeof(throttle_event),
8599 : },
8600 0 : .time = perf_event_clock(event),
8601 0 : .id = primary_event_id(event),
8602 : .stream_id = event->id,
8603 : };
8604 :
8605 0 : if (enable)
8606 0 : throttle_event.header.type = PERF_RECORD_UNTHROTTLE;
8607 :
8608 0 : perf_event_header__init_id(&throttle_event.header, &sample, event);
8609 :
8610 0 : ret = perf_output_begin(&handle, &sample, event,
8611 0 : throttle_event.header.size);
8612 0 : if (ret)
8613 0 : return;
8614 :
8615 0 : perf_output_put(&handle, throttle_event);
8616 0 : perf_event__output_id_sample(event, &handle, &sample);
8617 0 : perf_output_end(&handle);
8618 : }
8619 :
8620 : /*
8621 : * ksymbol register/unregister tracking
8622 : */
8623 :
8624 : struct perf_ksymbol_event {
8625 : const char *name;
8626 : int name_len;
8627 : struct {
8628 : struct perf_event_header header;
8629 : u64 addr;
8630 : u32 len;
8631 : u16 ksym_type;
8632 : u16 flags;
8633 : } event_id;
8634 : };
8635 :
8636 0 : static int perf_event_ksymbol_match(struct perf_event *event)
8637 : {
8638 0 : return event->attr.ksymbol;
8639 : }
8640 :
8641 0 : static void perf_event_ksymbol_output(struct perf_event *event, void *data)
8642 : {
8643 0 : struct perf_ksymbol_event *ksymbol_event = data;
8644 0 : struct perf_output_handle handle;
8645 0 : struct perf_sample_data sample;
8646 0 : int ret;
8647 :
8648 0 : if (!perf_event_ksymbol_match(event))
8649 0 : return;
8650 :
8651 0 : perf_event_header__init_id(&ksymbol_event->event_id.header,
8652 : &sample, event);
8653 0 : ret = perf_output_begin(&handle, &sample, event,
8654 0 : ksymbol_event->event_id.header.size);
8655 0 : if (ret)
8656 : return;
8657 :
8658 0 : perf_output_put(&handle, ksymbol_event->event_id);
8659 0 : __output_copy(&handle, ksymbol_event->name, ksymbol_event->name_len);
8660 0 : perf_event__output_id_sample(event, &handle, &sample);
8661 :
8662 0 : perf_output_end(&handle);
8663 : }
8664 :
8665 0 : void perf_event_ksymbol(u16 ksym_type, u64 addr, u32 len, bool unregister,
8666 : const char *sym)
8667 : {
8668 0 : struct perf_ksymbol_event ksymbol_event;
8669 0 : char name[KSYM_NAME_LEN];
8670 0 : u16 flags = 0;
8671 0 : int name_len;
8672 :
8673 0 : if (!atomic_read(&nr_ksymbol_events))
8674 0 : return;
8675 :
8676 0 : if (ksym_type >= PERF_RECORD_KSYMBOL_TYPE_MAX ||
8677 : ksym_type == PERF_RECORD_KSYMBOL_TYPE_UNKNOWN)
8678 0 : goto err;
8679 :
8680 0 : strlcpy(name, sym, KSYM_NAME_LEN);
8681 0 : name_len = strlen(name) + 1;
8682 0 : while (!IS_ALIGNED(name_len, sizeof(u64)))
8683 0 : name[name_len++] = '\0';
8684 0 : BUILD_BUG_ON(KSYM_NAME_LEN % sizeof(u64));
8685 :
8686 0 : if (unregister)
8687 0 : flags |= PERF_RECORD_KSYMBOL_FLAGS_UNREGISTER;
8688 :
8689 0 : ksymbol_event = (struct perf_ksymbol_event){
8690 : .name = name,
8691 : .name_len = name_len,
8692 : .event_id = {
8693 : .header = {
8694 : .type = PERF_RECORD_KSYMBOL,
8695 0 : .size = sizeof(ksymbol_event.event_id) +
8696 : name_len,
8697 : },
8698 : .addr = addr,
8699 : .len = len,
8700 : .ksym_type = ksym_type,
8701 : .flags = flags,
8702 : },
8703 : };
8704 :
8705 0 : perf_iterate_sb(perf_event_ksymbol_output, &ksymbol_event, NULL);
8706 0 : return;
8707 0 : err:
8708 0 : WARN_ONCE(1, "%s: Invalid KSYMBOL type 0x%x\n", __func__, ksym_type);
8709 : }
8710 :
8711 : /*
8712 : * bpf program load/unload tracking
8713 : */
8714 :
8715 : struct perf_bpf_event {
8716 : struct bpf_prog *prog;
8717 : struct {
8718 : struct perf_event_header header;
8719 : u16 type;
8720 : u16 flags;
8721 : u32 id;
8722 : u8 tag[BPF_TAG_SIZE];
8723 : } event_id;
8724 : };
8725 :
8726 0 : static int perf_event_bpf_match(struct perf_event *event)
8727 : {
8728 0 : return event->attr.bpf_event;
8729 : }
8730 :
8731 0 : static void perf_event_bpf_output(struct perf_event *event, void *data)
8732 : {
8733 0 : struct perf_bpf_event *bpf_event = data;
8734 0 : struct perf_output_handle handle;
8735 0 : struct perf_sample_data sample;
8736 0 : int ret;
8737 :
8738 0 : if (!perf_event_bpf_match(event))
8739 0 : return;
8740 :
8741 0 : perf_event_header__init_id(&bpf_event->event_id.header,
8742 : &sample, event);
8743 0 : ret = perf_output_begin(&handle, data, event,
8744 0 : bpf_event->event_id.header.size);
8745 0 : if (ret)
8746 : return;
8747 :
8748 0 : perf_output_put(&handle, bpf_event->event_id);
8749 0 : perf_event__output_id_sample(event, &handle, &sample);
8750 :
8751 0 : perf_output_end(&handle);
8752 : }
8753 :
8754 0 : static void perf_event_bpf_emit_ksymbols(struct bpf_prog *prog,
8755 : enum perf_bpf_event_type type)
8756 : {
8757 0 : bool unregister = type == PERF_BPF_EVENT_PROG_UNLOAD;
8758 0 : int i;
8759 :
8760 0 : if (prog->aux->func_cnt == 0) {
8761 0 : perf_event_ksymbol(PERF_RECORD_KSYMBOL_TYPE_BPF,
8762 0 : (u64)(unsigned long)prog->bpf_func,
8763 : prog->jited_len, unregister,
8764 0 : prog->aux->ksym.name);
8765 : } else {
8766 0 : for (i = 0; i < prog->aux->func_cnt; i++) {
8767 0 : struct bpf_prog *subprog = prog->aux->func[i];
8768 :
8769 0 : perf_event_ksymbol(
8770 : PERF_RECORD_KSYMBOL_TYPE_BPF,
8771 0 : (u64)(unsigned long)subprog->bpf_func,
8772 : subprog->jited_len, unregister,
8773 0 : prog->aux->ksym.name);
8774 : }
8775 : }
8776 0 : }
8777 :
8778 0 : void perf_event_bpf_event(struct bpf_prog *prog,
8779 : enum perf_bpf_event_type type,
8780 : u16 flags)
8781 : {
8782 0 : struct perf_bpf_event bpf_event;
8783 :
8784 0 : if (type <= PERF_BPF_EVENT_UNKNOWN ||
8785 : type >= PERF_BPF_EVENT_MAX)
8786 0 : return;
8787 :
8788 0 : switch (type) {
8789 : case PERF_BPF_EVENT_PROG_LOAD:
8790 : case PERF_BPF_EVENT_PROG_UNLOAD:
8791 0 : if (atomic_read(&nr_ksymbol_events))
8792 0 : perf_event_bpf_emit_ksymbols(prog, type);
8793 : break;
8794 : default:
8795 : break;
8796 : }
8797 :
8798 0 : if (!atomic_read(&nr_bpf_events))
8799 : return;
8800 :
8801 0 : bpf_event = (struct perf_bpf_event){
8802 : .prog = prog,
8803 : .event_id = {
8804 : .header = {
8805 : .type = PERF_RECORD_BPF_EVENT,
8806 : .size = sizeof(bpf_event.event_id),
8807 : },
8808 : .type = type,
8809 : .flags = flags,
8810 0 : .id = prog->aux->id,
8811 : },
8812 : };
8813 :
8814 0 : BUILD_BUG_ON(BPF_TAG_SIZE % sizeof(u64));
8815 :
8816 0 : memcpy(bpf_event.event_id.tag, prog->tag, BPF_TAG_SIZE);
8817 0 : perf_iterate_sb(perf_event_bpf_output, &bpf_event, NULL);
8818 : }
8819 :
8820 : struct perf_text_poke_event {
8821 : const void *old_bytes;
8822 : const void *new_bytes;
8823 : size_t pad;
8824 : u16 old_len;
8825 : u16 new_len;
8826 :
8827 : struct {
8828 : struct perf_event_header header;
8829 :
8830 : u64 addr;
8831 : } event_id;
8832 : };
8833 :
8834 0 : static int perf_event_text_poke_match(struct perf_event *event)
8835 : {
8836 0 : return event->attr.text_poke;
8837 : }
8838 :
8839 0 : static void perf_event_text_poke_output(struct perf_event *event, void *data)
8840 : {
8841 0 : struct perf_text_poke_event *text_poke_event = data;
8842 0 : struct perf_output_handle handle;
8843 0 : struct perf_sample_data sample;
8844 0 : u64 padding = 0;
8845 0 : int ret;
8846 :
8847 0 : if (!perf_event_text_poke_match(event))
8848 0 : return;
8849 :
8850 0 : perf_event_header__init_id(&text_poke_event->event_id.header, &sample, event);
8851 :
8852 0 : ret = perf_output_begin(&handle, &sample, event,
8853 0 : text_poke_event->event_id.header.size);
8854 0 : if (ret)
8855 : return;
8856 :
8857 0 : perf_output_put(&handle, text_poke_event->event_id);
8858 0 : perf_output_put(&handle, text_poke_event->old_len);
8859 0 : perf_output_put(&handle, text_poke_event->new_len);
8860 :
8861 0 : __output_copy(&handle, text_poke_event->old_bytes, text_poke_event->old_len);
8862 0 : __output_copy(&handle, text_poke_event->new_bytes, text_poke_event->new_len);
8863 :
8864 0 : if (text_poke_event->pad)
8865 0 : __output_copy(&handle, &padding, text_poke_event->pad);
8866 :
8867 0 : perf_event__output_id_sample(event, &handle, &sample);
8868 :
8869 0 : perf_output_end(&handle);
8870 : }
8871 :
8872 38 : void perf_event_text_poke(const void *addr, const void *old_bytes,
8873 : size_t old_len, const void *new_bytes, size_t new_len)
8874 : {
8875 38 : struct perf_text_poke_event text_poke_event;
8876 38 : size_t tot, pad;
8877 :
8878 38 : if (!atomic_read(&nr_text_poke_events))
8879 38 : return;
8880 :
8881 0 : tot = sizeof(text_poke_event.old_len) + old_len;
8882 0 : tot += sizeof(text_poke_event.new_len) + new_len;
8883 0 : pad = ALIGN(tot, sizeof(u64)) - tot;
8884 :
8885 0 : text_poke_event = (struct perf_text_poke_event){
8886 : .old_bytes = old_bytes,
8887 : .new_bytes = new_bytes,
8888 : .pad = pad,
8889 : .old_len = old_len,
8890 : .new_len = new_len,
8891 : .event_id = {
8892 : .header = {
8893 : .type = PERF_RECORD_TEXT_POKE,
8894 : .misc = PERF_RECORD_MISC_KERNEL,
8895 0 : .size = sizeof(text_poke_event.event_id) + tot + pad,
8896 : },
8897 0 : .addr = (unsigned long)addr,
8898 : },
8899 : };
8900 :
8901 0 : perf_iterate_sb(perf_event_text_poke_output, &text_poke_event, NULL);
8902 : }
8903 :
8904 0 : void perf_event_itrace_started(struct perf_event *event)
8905 : {
8906 0 : event->attach_state |= PERF_ATTACH_ITRACE;
8907 0 : }
8908 :
8909 0 : static void perf_log_itrace_start(struct perf_event *event)
8910 : {
8911 0 : struct perf_output_handle handle;
8912 0 : struct perf_sample_data sample;
8913 0 : struct perf_aux_event {
8914 : struct perf_event_header header;
8915 : u32 pid;
8916 : u32 tid;
8917 : } rec;
8918 0 : int ret;
8919 :
8920 0 : if (event->parent)
8921 0 : event = event->parent;
8922 :
8923 0 : if (!(event->pmu->capabilities & PERF_PMU_CAP_ITRACE) ||
8924 0 : event->attach_state & PERF_ATTACH_ITRACE)
8925 0 : return;
8926 :
8927 0 : rec.header.type = PERF_RECORD_ITRACE_START;
8928 0 : rec.header.misc = 0;
8929 0 : rec.header.size = sizeof(rec);
8930 0 : rec.pid = perf_event_pid(event, current);
8931 0 : rec.tid = perf_event_tid(event, current);
8932 :
8933 0 : perf_event_header__init_id(&rec.header, &sample, event);
8934 0 : ret = perf_output_begin(&handle, &sample, event, rec.header.size);
8935 :
8936 0 : if (ret)
8937 : return;
8938 :
8939 0 : perf_output_put(&handle, rec);
8940 0 : perf_event__output_id_sample(event, &handle, &sample);
8941 :
8942 0 : perf_output_end(&handle);
8943 : }
8944 :
8945 : static int
8946 0 : __perf_event_account_interrupt(struct perf_event *event, int throttle)
8947 : {
8948 0 : struct hw_perf_event *hwc = &event->hw;
8949 0 : int ret = 0;
8950 0 : u64 seq;
8951 :
8952 0 : seq = __this_cpu_read(perf_throttled_seq);
8953 0 : if (seq != hwc->interrupts_seq) {
8954 0 : hwc->interrupts_seq = seq;
8955 0 : hwc->interrupts = 1;
8956 : } else {
8957 0 : hwc->interrupts++;
8958 0 : if (unlikely(throttle
8959 : && hwc->interrupts >= max_samples_per_tick)) {
8960 0 : __this_cpu_inc(perf_throttled_count);
8961 0 : tick_dep_set_cpu(smp_processor_id(), TICK_DEP_BIT_PERF_EVENTS);
8962 0 : hwc->interrupts = MAX_INTERRUPTS;
8963 0 : perf_log_throttle(event, 0);
8964 0 : ret = 1;
8965 : }
8966 : }
8967 :
8968 0 : if (event->attr.freq) {
8969 0 : u64 now = perf_clock();
8970 0 : s64 delta = now - hwc->freq_time_stamp;
8971 :
8972 0 : hwc->freq_time_stamp = now;
8973 :
8974 0 : if (delta > 0 && delta < 2*TICK_NSEC)
8975 0 : perf_adjust_period(event, delta, hwc->last_period, true);
8976 : }
8977 :
8978 0 : return ret;
8979 : }
8980 :
8981 0 : int perf_event_account_interrupt(struct perf_event *event)
8982 : {
8983 0 : return __perf_event_account_interrupt(event, 1);
8984 : }
8985 :
8986 : /*
8987 : * Generic event overflow handling, sampling.
8988 : */
8989 :
8990 0 : static int __perf_event_overflow(struct perf_event *event,
8991 : int throttle, struct perf_sample_data *data,
8992 : struct pt_regs *regs)
8993 : {
8994 0 : int events = atomic_read(&event->event_limit);
8995 0 : int ret = 0;
8996 :
8997 : /*
8998 : * Non-sampling counters might still use the PMI to fold short
8999 : * hardware counters, ignore those.
9000 : */
9001 0 : if (unlikely(!is_sampling_event(event)))
9002 : return 0;
9003 :
9004 0 : ret = __perf_event_account_interrupt(event, throttle);
9005 :
9006 : /*
9007 : * XXX event_limit might not quite work as expected on inherited
9008 : * events
9009 : */
9010 :
9011 0 : event->pending_kill = POLL_IN;
9012 0 : if (events && atomic_dec_and_test(&event->event_limit)) {
9013 0 : ret = 1;
9014 0 : event->pending_kill = POLL_HUP;
9015 :
9016 0 : perf_event_disable_inatomic(event);
9017 : }
9018 :
9019 0 : READ_ONCE(event->overflow_handler)(event, data, regs);
9020 :
9021 0 : if (*perf_event_fasync(event) && event->pending_kill) {
9022 0 : event->pending_wakeup = 1;
9023 0 : irq_work_queue(&event->pending);
9024 : }
9025 :
9026 : return ret;
9027 : }
9028 :
9029 0 : int perf_event_overflow(struct perf_event *event,
9030 : struct perf_sample_data *data,
9031 : struct pt_regs *regs)
9032 : {
9033 0 : return __perf_event_overflow(event, 1, data, regs);
9034 : }
9035 :
9036 : /*
9037 : * Generic software event infrastructure
9038 : */
9039 :
9040 : struct swevent_htable {
9041 : struct swevent_hlist *swevent_hlist;
9042 : struct mutex hlist_mutex;
9043 : int hlist_refcount;
9044 :
9045 : /* Recursion avoidance in each contexts */
9046 : int recursion[PERF_NR_CONTEXTS];
9047 : };
9048 :
9049 : static DEFINE_PER_CPU(struct swevent_htable, swevent_htable);
9050 :
9051 : /*
9052 : * We directly increment event->count and keep a second value in
9053 : * event->hw.period_left to count intervals. This period event
9054 : * is kept in the range [-sample_period, 0] so that we can use the
9055 : * sign as trigger.
9056 : */
9057 :
9058 0 : u64 perf_swevent_set_period(struct perf_event *event)
9059 : {
9060 0 : struct hw_perf_event *hwc = &event->hw;
9061 0 : u64 period = hwc->last_period;
9062 0 : u64 nr, offset;
9063 0 : s64 old, val;
9064 :
9065 0 : hwc->last_period = hwc->sample_period;
9066 :
9067 0 : again:
9068 0 : old = val = local64_read(&hwc->period_left);
9069 0 : if (val < 0)
9070 : return 0;
9071 :
9072 0 : nr = div64_u64(period + val, period);
9073 0 : offset = nr * period;
9074 0 : val -= offset;
9075 0 : if (local64_cmpxchg(&hwc->period_left, old, val) != old)
9076 0 : goto again;
9077 :
9078 : return nr;
9079 : }
9080 :
9081 0 : static void perf_swevent_overflow(struct perf_event *event, u64 overflow,
9082 : struct perf_sample_data *data,
9083 : struct pt_regs *regs)
9084 : {
9085 0 : struct hw_perf_event *hwc = &event->hw;
9086 0 : int throttle = 0;
9087 :
9088 0 : if (!overflow)
9089 0 : overflow = perf_swevent_set_period(event);
9090 :
9091 0 : if (hwc->interrupts == MAX_INTERRUPTS)
9092 : return;
9093 :
9094 0 : for (; overflow; overflow--) {
9095 0 : if (__perf_event_overflow(event, throttle,
9096 : data, regs)) {
9097 : /*
9098 : * We inhibit the overflow from happening when
9099 : * hwc->interrupts == MAX_INTERRUPTS.
9100 : */
9101 : break;
9102 : }
9103 0 : throttle = 1;
9104 : }
9105 : }
9106 :
9107 0 : static void perf_swevent_event(struct perf_event *event, u64 nr,
9108 : struct perf_sample_data *data,
9109 : struct pt_regs *regs)
9110 : {
9111 0 : struct hw_perf_event *hwc = &event->hw;
9112 :
9113 0 : local64_add(nr, &event->count);
9114 :
9115 0 : if (!regs)
9116 : return;
9117 :
9118 0 : if (!is_sampling_event(event))
9119 : return;
9120 :
9121 0 : if ((event->attr.sample_type & PERF_SAMPLE_PERIOD) && !event->attr.freq) {
9122 0 : data->period = nr;
9123 0 : return perf_swevent_overflow(event, 1, data, regs);
9124 : } else
9125 0 : data->period = event->hw.last_period;
9126 :
9127 0 : if (nr == 1 && hwc->sample_period == 1 && !event->attr.freq)
9128 0 : return perf_swevent_overflow(event, 1, data, regs);
9129 :
9130 0 : if (local64_add_negative(nr, &hwc->period_left))
9131 : return;
9132 :
9133 0 : perf_swevent_overflow(event, 0, data, regs);
9134 : }
9135 :
9136 0 : static int perf_exclude_event(struct perf_event *event,
9137 : struct pt_regs *regs)
9138 : {
9139 0 : if (event->hw.state & PERF_HES_STOPPED)
9140 : return 1;
9141 :
9142 0 : if (regs) {
9143 0 : if (event->attr.exclude_user && user_mode(regs))
9144 : return 1;
9145 :
9146 0 : if (event->attr.exclude_kernel && !user_mode(regs))
9147 0 : return 1;
9148 : }
9149 :
9150 : return 0;
9151 : }
9152 :
9153 0 : static int perf_swevent_match(struct perf_event *event,
9154 : enum perf_type_id type,
9155 : u32 event_id,
9156 : struct perf_sample_data *data,
9157 : struct pt_regs *regs)
9158 : {
9159 0 : if (event->attr.type != type)
9160 : return 0;
9161 :
9162 0 : if (event->attr.config != event_id)
9163 : return 0;
9164 :
9165 0 : if (perf_exclude_event(event, regs))
9166 0 : return 0;
9167 :
9168 : return 1;
9169 : }
9170 :
9171 0 : static inline u64 swevent_hash(u64 type, u32 event_id)
9172 : {
9173 0 : u64 val = event_id | (type << 32);
9174 :
9175 0 : return hash_64(val, SWEVENT_HLIST_BITS);
9176 : }
9177 :
9178 : static inline struct hlist_head *
9179 0 : __find_swevent_head(struct swevent_hlist *hlist, u64 type, u32 event_id)
9180 : {
9181 0 : u64 hash = swevent_hash(type, event_id);
9182 :
9183 0 : return &hlist->heads[hash];
9184 : }
9185 :
9186 : /* For the read side: events when they trigger */
9187 : static inline struct hlist_head *
9188 0 : find_swevent_head_rcu(struct swevent_htable *swhash, u64 type, u32 event_id)
9189 : {
9190 0 : struct swevent_hlist *hlist;
9191 :
9192 0 : hlist = rcu_dereference(swhash->swevent_hlist);
9193 0 : if (!hlist)
9194 : return NULL;
9195 :
9196 0 : return __find_swevent_head(hlist, type, event_id);
9197 : }
9198 :
9199 : /* For the event head insertion and removal in the hlist */
9200 : static inline struct hlist_head *
9201 0 : find_swevent_head(struct swevent_htable *swhash, struct perf_event *event)
9202 : {
9203 0 : struct swevent_hlist *hlist;
9204 0 : u32 event_id = event->attr.config;
9205 0 : u64 type = event->attr.type;
9206 :
9207 : /*
9208 : * Event scheduling is always serialized against hlist allocation
9209 : * and release. Which makes the protected version suitable here.
9210 : * The context lock guarantees that.
9211 : */
9212 0 : hlist = rcu_dereference_protected(swhash->swevent_hlist,
9213 : lockdep_is_held(&event->ctx->lock));
9214 0 : if (!hlist)
9215 : return NULL;
9216 :
9217 0 : return __find_swevent_head(hlist, type, event_id);
9218 : }
9219 :
9220 0 : static void do_perf_sw_event(enum perf_type_id type, u32 event_id,
9221 : u64 nr,
9222 : struct perf_sample_data *data,
9223 : struct pt_regs *regs)
9224 : {
9225 0 : struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9226 0 : struct perf_event *event;
9227 0 : struct hlist_head *head;
9228 :
9229 0 : rcu_read_lock();
9230 0 : head = find_swevent_head_rcu(swhash, type, event_id);
9231 0 : if (!head)
9232 0 : goto end;
9233 :
9234 0 : hlist_for_each_entry_rcu(event, head, hlist_entry) {
9235 0 : if (perf_swevent_match(event, type, event_id, data, regs))
9236 0 : perf_swevent_event(event, nr, data, regs);
9237 : }
9238 0 : end:
9239 0 : rcu_read_unlock();
9240 0 : }
9241 :
9242 : DEFINE_PER_CPU(struct pt_regs, __perf_regs[4]);
9243 :
9244 0 : int perf_swevent_get_recursion_context(void)
9245 : {
9246 0 : struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9247 :
9248 0 : return get_recursion_context(swhash->recursion);
9249 : }
9250 : EXPORT_SYMBOL_GPL(perf_swevent_get_recursion_context);
9251 :
9252 0 : void perf_swevent_put_recursion_context(int rctx)
9253 : {
9254 0 : struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9255 :
9256 0 : put_recursion_context(swhash->recursion, rctx);
9257 0 : }
9258 :
9259 0 : void ___perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
9260 : {
9261 0 : struct perf_sample_data data;
9262 :
9263 0 : if (WARN_ON_ONCE(!regs))
9264 0 : return;
9265 :
9266 0 : perf_sample_data_init(&data, addr, 0);
9267 0 : do_perf_sw_event(PERF_TYPE_SOFTWARE, event_id, nr, &data, regs);
9268 : }
9269 :
9270 0 : void __perf_sw_event(u32 event_id, u64 nr, struct pt_regs *regs, u64 addr)
9271 : {
9272 0 : int rctx;
9273 :
9274 0 : preempt_disable_notrace();
9275 0 : rctx = perf_swevent_get_recursion_context();
9276 0 : if (unlikely(rctx < 0))
9277 0 : goto fail;
9278 :
9279 0 : ___perf_sw_event(event_id, nr, regs, addr);
9280 :
9281 0 : perf_swevent_put_recursion_context(rctx);
9282 0 : fail:
9283 0 : preempt_enable_notrace();
9284 0 : }
9285 :
9286 0 : static void perf_swevent_read(struct perf_event *event)
9287 : {
9288 0 : }
9289 :
9290 0 : static int perf_swevent_add(struct perf_event *event, int flags)
9291 : {
9292 0 : struct swevent_htable *swhash = this_cpu_ptr(&swevent_htable);
9293 0 : struct hw_perf_event *hwc = &event->hw;
9294 0 : struct hlist_head *head;
9295 :
9296 0 : if (is_sampling_event(event)) {
9297 0 : hwc->last_period = hwc->sample_period;
9298 0 : perf_swevent_set_period(event);
9299 : }
9300 :
9301 0 : hwc->state = !(flags & PERF_EF_START);
9302 :
9303 0 : head = find_swevent_head(swhash, event);
9304 0 : if (WARN_ON_ONCE(!head))
9305 : return -EINVAL;
9306 :
9307 0 : hlist_add_head_rcu(&event->hlist_entry, head);
9308 0 : perf_event_update_userpage(event);
9309 :
9310 0 : return 0;
9311 : }
9312 :
9313 0 : static void perf_swevent_del(struct perf_event *event, int flags)
9314 : {
9315 0 : hlist_del_rcu(&event->hlist_entry);
9316 0 : }
9317 :
9318 0 : static void perf_swevent_start(struct perf_event *event, int flags)
9319 : {
9320 0 : event->hw.state = 0;
9321 0 : }
9322 :
9323 0 : static void perf_swevent_stop(struct perf_event *event, int flags)
9324 : {
9325 0 : event->hw.state = PERF_HES_STOPPED;
9326 0 : }
9327 :
9328 : /* Deref the hlist from the update side */
9329 : static inline struct swevent_hlist *
9330 0 : swevent_hlist_deref(struct swevent_htable *swhash)
9331 : {
9332 0 : return rcu_dereference_protected(swhash->swevent_hlist,
9333 : lockdep_is_held(&swhash->hlist_mutex));
9334 : }
9335 :
9336 0 : static void swevent_hlist_release(struct swevent_htable *swhash)
9337 : {
9338 0 : struct swevent_hlist *hlist = swevent_hlist_deref(swhash);
9339 :
9340 0 : if (!hlist)
9341 : return;
9342 :
9343 0 : RCU_INIT_POINTER(swhash->swevent_hlist, NULL);
9344 0 : kfree_rcu(hlist, rcu_head);
9345 : }
9346 :
9347 0 : static void swevent_hlist_put_cpu(int cpu)
9348 : {
9349 0 : struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
9350 :
9351 0 : mutex_lock(&swhash->hlist_mutex);
9352 :
9353 0 : if (!--swhash->hlist_refcount)
9354 0 : swevent_hlist_release(swhash);
9355 :
9356 0 : mutex_unlock(&swhash->hlist_mutex);
9357 0 : }
9358 :
9359 0 : static void swevent_hlist_put(void)
9360 : {
9361 0 : int cpu;
9362 :
9363 0 : for_each_possible_cpu(cpu)
9364 0 : swevent_hlist_put_cpu(cpu);
9365 0 : }
9366 :
9367 0 : static int swevent_hlist_get_cpu(int cpu)
9368 : {
9369 0 : struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
9370 0 : int err = 0;
9371 :
9372 0 : mutex_lock(&swhash->hlist_mutex);
9373 0 : if (!swevent_hlist_deref(swhash) &&
9374 0 : cpumask_test_cpu(cpu, perf_online_mask)) {
9375 0 : struct swevent_hlist *hlist;
9376 :
9377 0 : hlist = kzalloc(sizeof(*hlist), GFP_KERNEL);
9378 0 : if (!hlist) {
9379 0 : err = -ENOMEM;
9380 0 : goto exit;
9381 : }
9382 0 : rcu_assign_pointer(swhash->swevent_hlist, hlist);
9383 : }
9384 0 : swhash->hlist_refcount++;
9385 0 : exit:
9386 0 : mutex_unlock(&swhash->hlist_mutex);
9387 :
9388 0 : return err;
9389 : }
9390 :
9391 0 : static int swevent_hlist_get(void)
9392 : {
9393 0 : int err, cpu, failed_cpu;
9394 :
9395 0 : mutex_lock(&pmus_lock);
9396 0 : for_each_possible_cpu(cpu) {
9397 0 : err = swevent_hlist_get_cpu(cpu);
9398 0 : if (err) {
9399 0 : failed_cpu = cpu;
9400 0 : goto fail;
9401 : }
9402 : }
9403 0 : mutex_unlock(&pmus_lock);
9404 0 : return 0;
9405 0 : fail:
9406 0 : for_each_possible_cpu(cpu) {
9407 0 : if (cpu == failed_cpu)
9408 : break;
9409 0 : swevent_hlist_put_cpu(cpu);
9410 : }
9411 0 : mutex_unlock(&pmus_lock);
9412 0 : return err;
9413 : }
9414 :
9415 : struct static_key perf_swevent_enabled[PERF_COUNT_SW_MAX];
9416 :
9417 0 : static void sw_perf_event_destroy(struct perf_event *event)
9418 : {
9419 0 : u64 event_id = event->attr.config;
9420 :
9421 0 : WARN_ON(event->parent);
9422 :
9423 0 : static_key_slow_dec(&perf_swevent_enabled[event_id]);
9424 0 : swevent_hlist_put();
9425 0 : }
9426 :
9427 0 : static int perf_swevent_init(struct perf_event *event)
9428 : {
9429 0 : u64 event_id = event->attr.config;
9430 :
9431 0 : if (event->attr.type != PERF_TYPE_SOFTWARE)
9432 : return -ENOENT;
9433 :
9434 : /*
9435 : * no branch sampling for software events
9436 : */
9437 0 : if (has_branch_stack(event))
9438 : return -EOPNOTSUPP;
9439 :
9440 0 : switch (event_id) {
9441 : case PERF_COUNT_SW_CPU_CLOCK:
9442 : case PERF_COUNT_SW_TASK_CLOCK:
9443 : return -ENOENT;
9444 :
9445 : default:
9446 0 : break;
9447 : }
9448 :
9449 0 : if (event_id >= PERF_COUNT_SW_MAX)
9450 : return -ENOENT;
9451 :
9452 0 : if (!event->parent) {
9453 0 : int err;
9454 :
9455 0 : err = swevent_hlist_get();
9456 0 : if (err)
9457 : return err;
9458 :
9459 0 : static_key_slow_inc(&perf_swevent_enabled[event_id]);
9460 0 : event->destroy = sw_perf_event_destroy;
9461 : }
9462 :
9463 : return 0;
9464 : }
9465 :
9466 : static struct pmu perf_swevent = {
9467 : .task_ctx_nr = perf_sw_context,
9468 :
9469 : .capabilities = PERF_PMU_CAP_NO_NMI,
9470 :
9471 : .event_init = perf_swevent_init,
9472 : .add = perf_swevent_add,
9473 : .del = perf_swevent_del,
9474 : .start = perf_swevent_start,
9475 : .stop = perf_swevent_stop,
9476 : .read = perf_swevent_read,
9477 : };
9478 :
9479 : #ifdef CONFIG_EVENT_TRACING
9480 :
9481 0 : static int perf_tp_filter_match(struct perf_event *event,
9482 : struct perf_sample_data *data)
9483 : {
9484 0 : void *record = data->raw->frag.data;
9485 :
9486 : /* only top level events have filters set */
9487 0 : if (event->parent)
9488 0 : event = event->parent;
9489 :
9490 0 : if (likely(!event->filter) || filter_match_preds(event->filter, record))
9491 0 : return 1;
9492 : return 0;
9493 : }
9494 :
9495 0 : static int perf_tp_event_match(struct perf_event *event,
9496 : struct perf_sample_data *data,
9497 : struct pt_regs *regs)
9498 : {
9499 0 : if (event->hw.state & PERF_HES_STOPPED)
9500 : return 0;
9501 : /*
9502 : * If exclude_kernel, only trace user-space tracepoints (uprobes)
9503 : */
9504 0 : if (event->attr.exclude_kernel && !user_mode(regs))
9505 : return 0;
9506 :
9507 0 : if (!perf_tp_filter_match(event, data))
9508 0 : return 0;
9509 :
9510 : return 1;
9511 : }
9512 :
9513 0 : void perf_trace_run_bpf_submit(void *raw_data, int size, int rctx,
9514 : struct trace_event_call *call, u64 count,
9515 : struct pt_regs *regs, struct hlist_head *head,
9516 : struct task_struct *task)
9517 : {
9518 0 : if (bpf_prog_array_valid(call)) {
9519 0 : *(struct pt_regs **)raw_data = regs;
9520 0 : if (!trace_call_bpf(call, raw_data) || hlist_empty(head)) {
9521 0 : perf_swevent_put_recursion_context(rctx);
9522 0 : return;
9523 : }
9524 : }
9525 0 : perf_tp_event(call->event.type, count, raw_data, size, regs, head,
9526 : rctx, task);
9527 : }
9528 : EXPORT_SYMBOL_GPL(perf_trace_run_bpf_submit);
9529 :
9530 0 : void perf_tp_event(u16 event_type, u64 count, void *record, int entry_size,
9531 : struct pt_regs *regs, struct hlist_head *head, int rctx,
9532 : struct task_struct *task)
9533 : {
9534 0 : struct perf_sample_data data;
9535 0 : struct perf_event *event;
9536 :
9537 0 : struct perf_raw_record raw = {
9538 : .frag = {
9539 : .size = entry_size,
9540 : .data = record,
9541 : },
9542 : };
9543 :
9544 0 : perf_sample_data_init(&data, 0, 0);
9545 0 : data.raw = &raw;
9546 :
9547 0 : perf_trace_buf_update(record, event_type);
9548 :
9549 0 : hlist_for_each_entry_rcu(event, head, hlist_entry) {
9550 0 : if (perf_tp_event_match(event, &data, regs))
9551 0 : perf_swevent_event(event, count, &data, regs);
9552 : }
9553 :
9554 : /*
9555 : * If we got specified a target task, also iterate its context and
9556 : * deliver this event there too.
9557 : */
9558 0 : if (task && task != current) {
9559 0 : struct perf_event_context *ctx;
9560 0 : struct trace_entry *entry = record;
9561 :
9562 0 : rcu_read_lock();
9563 0 : ctx = rcu_dereference(task->perf_event_ctxp[perf_sw_context]);
9564 0 : if (!ctx)
9565 0 : goto unlock;
9566 :
9567 0 : list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
9568 0 : if (event->cpu != smp_processor_id())
9569 0 : continue;
9570 0 : if (event->attr.type != PERF_TYPE_TRACEPOINT)
9571 0 : continue;
9572 0 : if (event->attr.config != entry->type)
9573 0 : continue;
9574 0 : if (perf_tp_event_match(event, &data, regs))
9575 0 : perf_swevent_event(event, count, &data, regs);
9576 : }
9577 0 : unlock:
9578 0 : rcu_read_unlock();
9579 : }
9580 :
9581 0 : perf_swevent_put_recursion_context(rctx);
9582 0 : }
9583 : EXPORT_SYMBOL_GPL(perf_tp_event);
9584 :
9585 0 : static void tp_perf_event_destroy(struct perf_event *event)
9586 : {
9587 0 : perf_trace_destroy(event);
9588 0 : }
9589 :
9590 0 : static int perf_tp_event_init(struct perf_event *event)
9591 : {
9592 0 : int err;
9593 :
9594 0 : if (event->attr.type != PERF_TYPE_TRACEPOINT)
9595 : return -ENOENT;
9596 :
9597 : /*
9598 : * no branch sampling for tracepoint events
9599 : */
9600 0 : if (has_branch_stack(event))
9601 : return -EOPNOTSUPP;
9602 :
9603 0 : err = perf_trace_init(event);
9604 0 : if (err)
9605 : return err;
9606 :
9607 0 : event->destroy = tp_perf_event_destroy;
9608 :
9609 0 : return 0;
9610 : }
9611 :
9612 : static struct pmu perf_tracepoint = {
9613 : .task_ctx_nr = perf_sw_context,
9614 :
9615 : .event_init = perf_tp_event_init,
9616 : .add = perf_trace_add,
9617 : .del = perf_trace_del,
9618 : .start = perf_swevent_start,
9619 : .stop = perf_swevent_stop,
9620 : .read = perf_swevent_read,
9621 : };
9622 :
9623 : #if defined(CONFIG_KPROBE_EVENTS) || defined(CONFIG_UPROBE_EVENTS)
9624 : /*
9625 : * Flags in config, used by dynamic PMU kprobe and uprobe
9626 : * The flags should match following PMU_FORMAT_ATTR().
9627 : *
9628 : * PERF_PROBE_CONFIG_IS_RETPROBE if set, create kretprobe/uretprobe
9629 : * if not set, create kprobe/uprobe
9630 : *
9631 : * The following values specify a reference counter (or semaphore in the
9632 : * terminology of tools like dtrace, systemtap, etc.) Userspace Statically
9633 : * Defined Tracepoints (USDT). Currently, we use 40 bit for the offset.
9634 : *
9635 : * PERF_UPROBE_REF_CTR_OFFSET_BITS # of bits in config as th offset
9636 : * PERF_UPROBE_REF_CTR_OFFSET_SHIFT # of bits to shift left
9637 : */
9638 : enum perf_probe_config {
9639 : PERF_PROBE_CONFIG_IS_RETPROBE = 1U << 0, /* [k,u]retprobe */
9640 : PERF_UPROBE_REF_CTR_OFFSET_BITS = 32,
9641 : PERF_UPROBE_REF_CTR_OFFSET_SHIFT = 64 - PERF_UPROBE_REF_CTR_OFFSET_BITS,
9642 : };
9643 :
9644 : PMU_FORMAT_ATTR(retprobe, "config:0");
9645 : #endif
9646 :
9647 : #ifdef CONFIG_KPROBE_EVENTS
9648 : static struct attribute *kprobe_attrs[] = {
9649 : &format_attr_retprobe.attr,
9650 : NULL,
9651 : };
9652 :
9653 : static struct attribute_group kprobe_format_group = {
9654 : .name = "format",
9655 : .attrs = kprobe_attrs,
9656 : };
9657 :
9658 : static const struct attribute_group *kprobe_attr_groups[] = {
9659 : &kprobe_format_group,
9660 : NULL,
9661 : };
9662 :
9663 : static int perf_kprobe_event_init(struct perf_event *event);
9664 : static struct pmu perf_kprobe = {
9665 : .task_ctx_nr = perf_sw_context,
9666 : .event_init = perf_kprobe_event_init,
9667 : .add = perf_trace_add,
9668 : .del = perf_trace_del,
9669 : .start = perf_swevent_start,
9670 : .stop = perf_swevent_stop,
9671 : .read = perf_swevent_read,
9672 : .attr_groups = kprobe_attr_groups,
9673 : };
9674 :
9675 : static int perf_kprobe_event_init(struct perf_event *event)
9676 : {
9677 : int err;
9678 : bool is_retprobe;
9679 :
9680 : if (event->attr.type != perf_kprobe.type)
9681 : return -ENOENT;
9682 :
9683 : if (!perfmon_capable())
9684 : return -EACCES;
9685 :
9686 : /*
9687 : * no branch sampling for probe events
9688 : */
9689 : if (has_branch_stack(event))
9690 : return -EOPNOTSUPP;
9691 :
9692 : is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
9693 : err = perf_kprobe_init(event, is_retprobe);
9694 : if (err)
9695 : return err;
9696 :
9697 : event->destroy = perf_kprobe_destroy;
9698 :
9699 : return 0;
9700 : }
9701 : #endif /* CONFIG_KPROBE_EVENTS */
9702 :
9703 : #ifdef CONFIG_UPROBE_EVENTS
9704 : PMU_FORMAT_ATTR(ref_ctr_offset, "config:32-63");
9705 :
9706 : static struct attribute *uprobe_attrs[] = {
9707 : &format_attr_retprobe.attr,
9708 : &format_attr_ref_ctr_offset.attr,
9709 : NULL,
9710 : };
9711 :
9712 : static struct attribute_group uprobe_format_group = {
9713 : .name = "format",
9714 : .attrs = uprobe_attrs,
9715 : };
9716 :
9717 : static const struct attribute_group *uprobe_attr_groups[] = {
9718 : &uprobe_format_group,
9719 : NULL,
9720 : };
9721 :
9722 : static int perf_uprobe_event_init(struct perf_event *event);
9723 : static struct pmu perf_uprobe = {
9724 : .task_ctx_nr = perf_sw_context,
9725 : .event_init = perf_uprobe_event_init,
9726 : .add = perf_trace_add,
9727 : .del = perf_trace_del,
9728 : .start = perf_swevent_start,
9729 : .stop = perf_swevent_stop,
9730 : .read = perf_swevent_read,
9731 : .attr_groups = uprobe_attr_groups,
9732 : };
9733 :
9734 : static int perf_uprobe_event_init(struct perf_event *event)
9735 : {
9736 : int err;
9737 : unsigned long ref_ctr_offset;
9738 : bool is_retprobe;
9739 :
9740 : if (event->attr.type != perf_uprobe.type)
9741 : return -ENOENT;
9742 :
9743 : if (!perfmon_capable())
9744 : return -EACCES;
9745 :
9746 : /*
9747 : * no branch sampling for probe events
9748 : */
9749 : if (has_branch_stack(event))
9750 : return -EOPNOTSUPP;
9751 :
9752 : is_retprobe = event->attr.config & PERF_PROBE_CONFIG_IS_RETPROBE;
9753 : ref_ctr_offset = event->attr.config >> PERF_UPROBE_REF_CTR_OFFSET_SHIFT;
9754 : err = perf_uprobe_init(event, ref_ctr_offset, is_retprobe);
9755 : if (err)
9756 : return err;
9757 :
9758 : event->destroy = perf_uprobe_destroy;
9759 :
9760 : return 0;
9761 : }
9762 : #endif /* CONFIG_UPROBE_EVENTS */
9763 :
9764 1 : static inline void perf_tp_register(void)
9765 : {
9766 1 : perf_pmu_register(&perf_tracepoint, "tracepoint", PERF_TYPE_TRACEPOINT);
9767 : #ifdef CONFIG_KPROBE_EVENTS
9768 : perf_pmu_register(&perf_kprobe, "kprobe", -1);
9769 : #endif
9770 : #ifdef CONFIG_UPROBE_EVENTS
9771 : perf_pmu_register(&perf_uprobe, "uprobe", -1);
9772 : #endif
9773 : }
9774 :
9775 0 : static void perf_event_free_filter(struct perf_event *event)
9776 : {
9777 0 : ftrace_profile_free_filter(event);
9778 : }
9779 :
9780 : #ifdef CONFIG_BPF_SYSCALL
9781 : static void bpf_overflow_handler(struct perf_event *event,
9782 : struct perf_sample_data *data,
9783 : struct pt_regs *regs)
9784 : {
9785 : struct bpf_perf_event_data_kern ctx = {
9786 : .data = data,
9787 : .event = event,
9788 : };
9789 : int ret = 0;
9790 :
9791 : ctx.regs = perf_arch_bpf_user_pt_regs(regs);
9792 : if (unlikely(__this_cpu_inc_return(bpf_prog_active) != 1))
9793 : goto out;
9794 : rcu_read_lock();
9795 : ret = BPF_PROG_RUN(event->prog, &ctx);
9796 : rcu_read_unlock();
9797 : out:
9798 : __this_cpu_dec(bpf_prog_active);
9799 : if (!ret)
9800 : return;
9801 :
9802 : event->orig_overflow_handler(event, data, regs);
9803 : }
9804 :
9805 : static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
9806 : {
9807 : struct bpf_prog *prog;
9808 :
9809 : if (event->overflow_handler_context)
9810 : /* hw breakpoint or kernel counter */
9811 : return -EINVAL;
9812 :
9813 : if (event->prog)
9814 : return -EEXIST;
9815 :
9816 : prog = bpf_prog_get_type(prog_fd, BPF_PROG_TYPE_PERF_EVENT);
9817 : if (IS_ERR(prog))
9818 : return PTR_ERR(prog);
9819 :
9820 : if (event->attr.precise_ip &&
9821 : prog->call_get_stack &&
9822 : (!(event->attr.sample_type & __PERF_SAMPLE_CALLCHAIN_EARLY) ||
9823 : event->attr.exclude_callchain_kernel ||
9824 : event->attr.exclude_callchain_user)) {
9825 : /*
9826 : * On perf_event with precise_ip, calling bpf_get_stack()
9827 : * may trigger unwinder warnings and occasional crashes.
9828 : * bpf_get_[stack|stackid] works around this issue by using
9829 : * callchain attached to perf_sample_data. If the
9830 : * perf_event does not full (kernel and user) callchain
9831 : * attached to perf_sample_data, do not allow attaching BPF
9832 : * program that calls bpf_get_[stack|stackid].
9833 : */
9834 : bpf_prog_put(prog);
9835 : return -EPROTO;
9836 : }
9837 :
9838 : event->prog = prog;
9839 : event->orig_overflow_handler = READ_ONCE(event->overflow_handler);
9840 : WRITE_ONCE(event->overflow_handler, bpf_overflow_handler);
9841 : return 0;
9842 : }
9843 :
9844 : static void perf_event_free_bpf_handler(struct perf_event *event)
9845 : {
9846 : struct bpf_prog *prog = event->prog;
9847 :
9848 : if (!prog)
9849 : return;
9850 :
9851 : WRITE_ONCE(event->overflow_handler, event->orig_overflow_handler);
9852 : event->prog = NULL;
9853 : bpf_prog_put(prog);
9854 : }
9855 : #else
9856 : static int perf_event_set_bpf_handler(struct perf_event *event, u32 prog_fd)
9857 : {
9858 : return -EOPNOTSUPP;
9859 : }
9860 : static void perf_event_free_bpf_handler(struct perf_event *event)
9861 : {
9862 : }
9863 : #endif
9864 :
9865 : /*
9866 : * returns true if the event is a tracepoint, or a kprobe/upprobe created
9867 : * with perf_event_open()
9868 : */
9869 0 : static inline bool perf_event_is_tracing(struct perf_event *event)
9870 : {
9871 0 : if (event->pmu == &perf_tracepoint)
9872 0 : return true;
9873 : #ifdef CONFIG_KPROBE_EVENTS
9874 : if (event->pmu == &perf_kprobe)
9875 : return true;
9876 : #endif
9877 : #ifdef CONFIG_UPROBE_EVENTS
9878 : if (event->pmu == &perf_uprobe)
9879 : return true;
9880 : #endif
9881 : return false;
9882 : }
9883 :
9884 0 : static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
9885 : {
9886 0 : bool is_kprobe, is_tracepoint, is_syscall_tp;
9887 0 : struct bpf_prog *prog;
9888 0 : int ret;
9889 :
9890 0 : if (!perf_event_is_tracing(event))
9891 0 : return perf_event_set_bpf_handler(event, prog_fd);
9892 :
9893 0 : is_kprobe = event->tp_event->flags & TRACE_EVENT_FL_UKPROBE;
9894 0 : is_tracepoint = event->tp_event->flags & TRACE_EVENT_FL_TRACEPOINT;
9895 0 : is_syscall_tp = is_syscall_trace_event(event->tp_event);
9896 0 : if (!is_kprobe && !is_tracepoint && !is_syscall_tp)
9897 : /* bpf programs can only be attached to u/kprobe or tracepoint */
9898 : return -EINVAL;
9899 :
9900 0 : prog = bpf_prog_get(prog_fd);
9901 0 : if (IS_ERR(prog))
9902 0 : return PTR_ERR(prog);
9903 :
9904 : if ((is_kprobe && prog->type != BPF_PROG_TYPE_KPROBE) ||
9905 : (is_tracepoint && prog->type != BPF_PROG_TYPE_TRACEPOINT) ||
9906 : (is_syscall_tp && prog->type != BPF_PROG_TYPE_TRACEPOINT)) {
9907 : /* valid fd, but invalid bpf program type */
9908 : bpf_prog_put(prog);
9909 : return -EINVAL;
9910 : }
9911 :
9912 : /* Kprobe override only works for kprobes, not uprobes. */
9913 : if (prog->kprobe_override &&
9914 : !(event->tp_event->flags & TRACE_EVENT_FL_KPROBE)) {
9915 : bpf_prog_put(prog);
9916 : return -EINVAL;
9917 : }
9918 :
9919 : if (is_tracepoint || is_syscall_tp) {
9920 : int off = trace_event_get_offsets(event->tp_event);
9921 :
9922 : if (prog->aux->max_ctx_offset > off) {
9923 : bpf_prog_put(prog);
9924 : return -EACCES;
9925 : }
9926 : }
9927 :
9928 : ret = perf_event_attach_bpf_prog(event, prog);
9929 : if (ret)
9930 : bpf_prog_put(prog);
9931 : return ret;
9932 : }
9933 :
9934 0 : static void perf_event_free_bpf_prog(struct perf_event *event)
9935 : {
9936 0 : if (!perf_event_is_tracing(event)) {
9937 : perf_event_free_bpf_handler(event);
9938 : return;
9939 : }
9940 0 : perf_event_detach_bpf_prog(event);
9941 : }
9942 :
9943 : #else
9944 :
9945 : static inline void perf_tp_register(void)
9946 : {
9947 : }
9948 :
9949 : static void perf_event_free_filter(struct perf_event *event)
9950 : {
9951 : }
9952 :
9953 : static int perf_event_set_bpf_prog(struct perf_event *event, u32 prog_fd)
9954 : {
9955 : return -ENOENT;
9956 : }
9957 :
9958 : static void perf_event_free_bpf_prog(struct perf_event *event)
9959 : {
9960 : }
9961 : #endif /* CONFIG_EVENT_TRACING */
9962 :
9963 : #ifdef CONFIG_HAVE_HW_BREAKPOINT
9964 0 : void perf_bp_event(struct perf_event *bp, void *data)
9965 : {
9966 0 : struct perf_sample_data sample;
9967 0 : struct pt_regs *regs = data;
9968 :
9969 0 : perf_sample_data_init(&sample, bp->attr.bp_addr, 0);
9970 :
9971 0 : if (!bp->hw.state && !perf_exclude_event(bp, regs))
9972 0 : perf_swevent_event(bp, 1, &sample, regs);
9973 0 : }
9974 : #endif
9975 :
9976 : /*
9977 : * Allocate a new address filter
9978 : */
9979 : static struct perf_addr_filter *
9980 0 : perf_addr_filter_new(struct perf_event *event, struct list_head *filters)
9981 : {
9982 0 : int node = cpu_to_node(event->cpu == -1 ? 0 : event->cpu);
9983 0 : struct perf_addr_filter *filter;
9984 :
9985 0 : filter = kzalloc_node(sizeof(*filter), GFP_KERNEL, node);
9986 0 : if (!filter)
9987 : return NULL;
9988 :
9989 0 : INIT_LIST_HEAD(&filter->entry);
9990 0 : list_add_tail(&filter->entry, filters);
9991 :
9992 0 : return filter;
9993 : }
9994 :
9995 0 : static void free_filters_list(struct list_head *filters)
9996 : {
9997 0 : struct perf_addr_filter *filter, *iter;
9998 :
9999 0 : list_for_each_entry_safe(filter, iter, filters, entry) {
10000 0 : path_put(&filter->path);
10001 0 : list_del(&filter->entry);
10002 0 : kfree(filter);
10003 : }
10004 0 : }
10005 :
10006 : /*
10007 : * Free existing address filters and optionally install new ones
10008 : */
10009 0 : static void perf_addr_filters_splice(struct perf_event *event,
10010 : struct list_head *head)
10011 : {
10012 0 : unsigned long flags;
10013 0 : LIST_HEAD(list);
10014 :
10015 0 : if (!has_addr_filter(event))
10016 0 : return;
10017 :
10018 : /* don't bother with children, they don't have their own filters */
10019 0 : if (event->parent)
10020 : return;
10021 :
10022 0 : raw_spin_lock_irqsave(&event->addr_filters.lock, flags);
10023 :
10024 0 : list_splice_init(&event->addr_filters.list, &list);
10025 0 : if (head)
10026 0 : list_splice(head, &event->addr_filters.list);
10027 :
10028 0 : raw_spin_unlock_irqrestore(&event->addr_filters.lock, flags);
10029 :
10030 0 : free_filters_list(&list);
10031 : }
10032 :
10033 : /*
10034 : * Scan through mm's vmas and see if one of them matches the
10035 : * @filter; if so, adjust filter's address range.
10036 : * Called with mm::mmap_lock down for reading.
10037 : */
10038 0 : static void perf_addr_filter_apply(struct perf_addr_filter *filter,
10039 : struct mm_struct *mm,
10040 : struct perf_addr_filter_range *fr)
10041 : {
10042 0 : struct vm_area_struct *vma;
10043 :
10044 0 : for (vma = mm->mmap; vma; vma = vma->vm_next) {
10045 0 : if (!vma->vm_file)
10046 0 : continue;
10047 :
10048 0 : if (perf_addr_filter_vma_adjust(filter, vma, fr))
10049 : return;
10050 : }
10051 : }
10052 :
10053 : /*
10054 : * Update event's address range filters based on the
10055 : * task's existing mappings, if any.
10056 : */
10057 0 : static void perf_event_addr_filters_apply(struct perf_event *event)
10058 : {
10059 0 : struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
10060 0 : struct task_struct *task = READ_ONCE(event->ctx->task);
10061 0 : struct perf_addr_filter *filter;
10062 0 : struct mm_struct *mm = NULL;
10063 0 : unsigned int count = 0;
10064 0 : unsigned long flags;
10065 :
10066 : /*
10067 : * We may observe TASK_TOMBSTONE, which means that the event tear-down
10068 : * will stop on the parent's child_mutex that our caller is also holding
10069 : */
10070 0 : if (task == TASK_TOMBSTONE)
10071 : return;
10072 :
10073 0 : if (ifh->nr_file_filters) {
10074 0 : mm = get_task_mm(event->ctx->task);
10075 0 : if (!mm)
10076 0 : goto restart;
10077 :
10078 0 : mmap_read_lock(mm);
10079 : }
10080 :
10081 0 : raw_spin_lock_irqsave(&ifh->lock, flags);
10082 0 : list_for_each_entry(filter, &ifh->list, entry) {
10083 0 : if (filter->path.dentry) {
10084 : /*
10085 : * Adjust base offset if the filter is associated to a
10086 : * binary that needs to be mapped:
10087 : */
10088 0 : event->addr_filter_ranges[count].start = 0;
10089 0 : event->addr_filter_ranges[count].size = 0;
10090 :
10091 0 : perf_addr_filter_apply(filter, mm, &event->addr_filter_ranges[count]);
10092 : } else {
10093 0 : event->addr_filter_ranges[count].start = filter->offset;
10094 0 : event->addr_filter_ranges[count].size = filter->size;
10095 : }
10096 :
10097 0 : count++;
10098 : }
10099 :
10100 0 : event->addr_filters_gen++;
10101 0 : raw_spin_unlock_irqrestore(&ifh->lock, flags);
10102 :
10103 0 : if (ifh->nr_file_filters) {
10104 0 : mmap_read_unlock(mm);
10105 :
10106 0 : mmput(mm);
10107 : }
10108 :
10109 0 : restart:
10110 0 : perf_event_stop(event, 1);
10111 : }
10112 :
10113 : /*
10114 : * Address range filtering: limiting the data to certain
10115 : * instruction address ranges. Filters are ioctl()ed to us from
10116 : * userspace as ascii strings.
10117 : *
10118 : * Filter string format:
10119 : *
10120 : * ACTION RANGE_SPEC
10121 : * where ACTION is one of the
10122 : * * "filter": limit the trace to this region
10123 : * * "start": start tracing from this address
10124 : * * "stop": stop tracing at this address/region;
10125 : * RANGE_SPEC is
10126 : * * for kernel addresses: <start address>[/<size>]
10127 : * * for object files: <start address>[/<size>]@</path/to/object/file>
10128 : *
10129 : * if <size> is not specified or is zero, the range is treated as a single
10130 : * address; not valid for ACTION=="filter".
10131 : */
10132 : enum {
10133 : IF_ACT_NONE = -1,
10134 : IF_ACT_FILTER,
10135 : IF_ACT_START,
10136 : IF_ACT_STOP,
10137 : IF_SRC_FILE,
10138 : IF_SRC_KERNEL,
10139 : IF_SRC_FILEADDR,
10140 : IF_SRC_KERNELADDR,
10141 : };
10142 :
10143 : enum {
10144 : IF_STATE_ACTION = 0,
10145 : IF_STATE_SOURCE,
10146 : IF_STATE_END,
10147 : };
10148 :
10149 : static const match_table_t if_tokens = {
10150 : { IF_ACT_FILTER, "filter" },
10151 : { IF_ACT_START, "start" },
10152 : { IF_ACT_STOP, "stop" },
10153 : { IF_SRC_FILE, "%u/%u@%s" },
10154 : { IF_SRC_KERNEL, "%u/%u" },
10155 : { IF_SRC_FILEADDR, "%u@%s" },
10156 : { IF_SRC_KERNELADDR, "%u" },
10157 : { IF_ACT_NONE, NULL },
10158 : };
10159 :
10160 : /*
10161 : * Address filter string parser
10162 : */
10163 : static int
10164 0 : perf_event_parse_addr_filter(struct perf_event *event, char *fstr,
10165 : struct list_head *filters)
10166 : {
10167 0 : struct perf_addr_filter *filter = NULL;
10168 0 : char *start, *orig, *filename = NULL;
10169 0 : substring_t args[MAX_OPT_ARGS];
10170 0 : int state = IF_STATE_ACTION, token;
10171 0 : unsigned int kernel = 0;
10172 0 : int ret = -EINVAL;
10173 :
10174 0 : orig = fstr = kstrdup(fstr, GFP_KERNEL);
10175 0 : if (!fstr)
10176 : return -ENOMEM;
10177 :
10178 0 : while ((start = strsep(&fstr, " ,\n")) != NULL) {
10179 0 : static const enum perf_addr_filter_action_t actions[] = {
10180 : [IF_ACT_FILTER] = PERF_ADDR_FILTER_ACTION_FILTER,
10181 : [IF_ACT_START] = PERF_ADDR_FILTER_ACTION_START,
10182 : [IF_ACT_STOP] = PERF_ADDR_FILTER_ACTION_STOP,
10183 : };
10184 0 : ret = -EINVAL;
10185 :
10186 0 : if (!*start)
10187 0 : continue;
10188 :
10189 : /* filter definition begins */
10190 0 : if (state == IF_STATE_ACTION) {
10191 0 : filter = perf_addr_filter_new(event, filters);
10192 0 : if (!filter)
10193 0 : goto fail;
10194 : }
10195 :
10196 0 : token = match_token(start, if_tokens, args);
10197 0 : switch (token) {
10198 0 : case IF_ACT_FILTER:
10199 : case IF_ACT_START:
10200 : case IF_ACT_STOP:
10201 0 : if (state != IF_STATE_ACTION)
10202 0 : goto fail;
10203 :
10204 0 : filter->action = actions[token];
10205 0 : state = IF_STATE_SOURCE;
10206 0 : break;
10207 :
10208 0 : case IF_SRC_KERNELADDR:
10209 : case IF_SRC_KERNEL:
10210 0 : kernel = 1;
10211 0 : fallthrough;
10212 :
10213 0 : case IF_SRC_FILEADDR:
10214 : case IF_SRC_FILE:
10215 0 : if (state != IF_STATE_SOURCE)
10216 0 : goto fail;
10217 :
10218 0 : *args[0].to = 0;
10219 0 : ret = kstrtoul(args[0].from, 0, &filter->offset);
10220 0 : if (ret)
10221 0 : goto fail;
10222 :
10223 0 : if (token == IF_SRC_KERNEL || token == IF_SRC_FILE) {
10224 0 : *args[1].to = 0;
10225 0 : ret = kstrtoul(args[1].from, 0, &filter->size);
10226 0 : if (ret)
10227 0 : goto fail;
10228 : }
10229 :
10230 0 : if (token == IF_SRC_FILE || token == IF_SRC_FILEADDR) {
10231 0 : int fpos = token == IF_SRC_FILE ? 2 : 1;
10232 :
10233 0 : kfree(filename);
10234 0 : filename = match_strdup(&args[fpos]);
10235 0 : if (!filename) {
10236 0 : ret = -ENOMEM;
10237 0 : goto fail;
10238 : }
10239 : }
10240 :
10241 : state = IF_STATE_END;
10242 : break;
10243 :
10244 0 : default:
10245 0 : goto fail;
10246 : }
10247 :
10248 : /*
10249 : * Filter definition is fully parsed, validate and install it.
10250 : * Make sure that it doesn't contradict itself or the event's
10251 : * attribute.
10252 : */
10253 0 : if (state == IF_STATE_END) {
10254 0 : ret = -EINVAL;
10255 0 : if (kernel && event->attr.exclude_kernel)
10256 0 : goto fail;
10257 :
10258 : /*
10259 : * ACTION "filter" must have a non-zero length region
10260 : * specified.
10261 : */
10262 0 : if (filter->action == PERF_ADDR_FILTER_ACTION_FILTER &&
10263 0 : !filter->size)
10264 0 : goto fail;
10265 :
10266 0 : if (!kernel) {
10267 0 : if (!filename)
10268 0 : goto fail;
10269 :
10270 : /*
10271 : * For now, we only support file-based filters
10272 : * in per-task events; doing so for CPU-wide
10273 : * events requires additional context switching
10274 : * trickery, since same object code will be
10275 : * mapped at different virtual addresses in
10276 : * different processes.
10277 : */
10278 0 : ret = -EOPNOTSUPP;
10279 0 : if (!event->ctx->task)
10280 0 : goto fail;
10281 :
10282 : /* look up the path and grab its inode */
10283 0 : ret = kern_path(filename, LOOKUP_FOLLOW,
10284 : &filter->path);
10285 0 : if (ret)
10286 0 : goto fail;
10287 :
10288 0 : ret = -EINVAL;
10289 0 : if (!filter->path.dentry ||
10290 0 : !S_ISREG(d_inode(filter->path.dentry)
10291 : ->i_mode))
10292 0 : goto fail;
10293 :
10294 0 : event->addr_filters.nr_file_filters++;
10295 : }
10296 :
10297 : /* ready to consume more filters */
10298 : state = IF_STATE_ACTION;
10299 : filter = NULL;
10300 : }
10301 : }
10302 :
10303 0 : if (state != IF_STATE_ACTION)
10304 0 : goto fail;
10305 :
10306 0 : kfree(filename);
10307 0 : kfree(orig);
10308 :
10309 0 : return 0;
10310 :
10311 0 : fail:
10312 0 : kfree(filename);
10313 0 : free_filters_list(filters);
10314 0 : kfree(orig);
10315 :
10316 0 : return ret;
10317 : }
10318 :
10319 : static int
10320 0 : perf_event_set_addr_filter(struct perf_event *event, char *filter_str)
10321 : {
10322 0 : LIST_HEAD(filters);
10323 0 : int ret;
10324 :
10325 : /*
10326 : * Since this is called in perf_ioctl() path, we're already holding
10327 : * ctx::mutex.
10328 : */
10329 0 : lockdep_assert_held(&event->ctx->mutex);
10330 :
10331 0 : if (WARN_ON_ONCE(event->parent))
10332 : return -EINVAL;
10333 :
10334 0 : ret = perf_event_parse_addr_filter(event, filter_str, &filters);
10335 0 : if (ret)
10336 0 : goto fail_clear_files;
10337 :
10338 0 : ret = event->pmu->addr_filters_validate(&filters);
10339 0 : if (ret)
10340 0 : goto fail_free_filters;
10341 :
10342 : /* remove existing filters, if any */
10343 0 : perf_addr_filters_splice(event, &filters);
10344 :
10345 : /* install new filters */
10346 0 : perf_event_for_each_child(event, perf_event_addr_filters_apply);
10347 :
10348 0 : return ret;
10349 :
10350 0 : fail_free_filters:
10351 0 : free_filters_list(&filters);
10352 :
10353 0 : fail_clear_files:
10354 0 : event->addr_filters.nr_file_filters = 0;
10355 :
10356 0 : return ret;
10357 : }
10358 :
10359 0 : static int perf_event_set_filter(struct perf_event *event, void __user *arg)
10360 : {
10361 0 : int ret = -EINVAL;
10362 0 : char *filter_str;
10363 :
10364 0 : filter_str = strndup_user(arg, PAGE_SIZE);
10365 0 : if (IS_ERR(filter_str))
10366 0 : return PTR_ERR(filter_str);
10367 :
10368 : #ifdef CONFIG_EVENT_TRACING
10369 0 : if (perf_event_is_tracing(event)) {
10370 0 : struct perf_event_context *ctx = event->ctx;
10371 :
10372 : /*
10373 : * Beware, here be dragons!!
10374 : *
10375 : * the tracepoint muck will deadlock against ctx->mutex, but
10376 : * the tracepoint stuff does not actually need it. So
10377 : * temporarily drop ctx->mutex. As per perf_event_ctx_lock() we
10378 : * already have a reference on ctx.
10379 : *
10380 : * This can result in event getting moved to a different ctx,
10381 : * but that does not affect the tracepoint state.
10382 : */
10383 0 : mutex_unlock(&ctx->mutex);
10384 0 : ret = ftrace_profile_set_filter(event, event->attr.config, filter_str);
10385 0 : mutex_lock(&ctx->mutex);
10386 : } else
10387 : #endif
10388 0 : if (has_addr_filter(event))
10389 0 : ret = perf_event_set_addr_filter(event, filter_str);
10390 :
10391 0 : kfree(filter_str);
10392 0 : return ret;
10393 : }
10394 :
10395 : /*
10396 : * hrtimer based swevent callback
10397 : */
10398 :
10399 0 : static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
10400 : {
10401 0 : enum hrtimer_restart ret = HRTIMER_RESTART;
10402 0 : struct perf_sample_data data;
10403 0 : struct pt_regs *regs;
10404 0 : struct perf_event *event;
10405 0 : u64 period;
10406 :
10407 0 : event = container_of(hrtimer, struct perf_event, hw.hrtimer);
10408 :
10409 0 : if (event->state != PERF_EVENT_STATE_ACTIVE)
10410 : return HRTIMER_NORESTART;
10411 :
10412 0 : event->pmu->read(event);
10413 :
10414 0 : perf_sample_data_init(&data, 0, event->hw.last_period);
10415 0 : regs = get_irq_regs();
10416 :
10417 0 : if (regs && !perf_exclude_event(event, regs)) {
10418 0 : if (!(event->attr.exclude_idle && is_idle_task(current)))
10419 0 : if (__perf_event_overflow(event, 1, &data, regs))
10420 0 : ret = HRTIMER_NORESTART;
10421 : }
10422 :
10423 0 : period = max_t(u64, 10000, event->hw.sample_period);
10424 0 : hrtimer_forward_now(hrtimer, ns_to_ktime(period));
10425 :
10426 0 : return ret;
10427 : }
10428 :
10429 0 : static void perf_swevent_start_hrtimer(struct perf_event *event)
10430 : {
10431 0 : struct hw_perf_event *hwc = &event->hw;
10432 0 : s64 period;
10433 :
10434 0 : if (!is_sampling_event(event))
10435 : return;
10436 :
10437 0 : period = local64_read(&hwc->period_left);
10438 0 : if (period) {
10439 0 : if (period < 0)
10440 0 : period = 10000;
10441 :
10442 0 : local64_set(&hwc->period_left, 0);
10443 : } else {
10444 0 : period = max_t(u64, 10000, hwc->sample_period);
10445 : }
10446 0 : hrtimer_start(&hwc->hrtimer, ns_to_ktime(period),
10447 : HRTIMER_MODE_REL_PINNED_HARD);
10448 : }
10449 :
10450 0 : static void perf_swevent_cancel_hrtimer(struct perf_event *event)
10451 : {
10452 0 : struct hw_perf_event *hwc = &event->hw;
10453 :
10454 0 : if (is_sampling_event(event)) {
10455 0 : ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
10456 0 : local64_set(&hwc->period_left, ktime_to_ns(remaining));
10457 :
10458 0 : hrtimer_cancel(&hwc->hrtimer);
10459 : }
10460 0 : }
10461 :
10462 0 : static void perf_swevent_init_hrtimer(struct perf_event *event)
10463 : {
10464 0 : struct hw_perf_event *hwc = &event->hw;
10465 :
10466 0 : if (!is_sampling_event(event))
10467 : return;
10468 :
10469 0 : hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);
10470 0 : hwc->hrtimer.function = perf_swevent_hrtimer;
10471 :
10472 : /*
10473 : * Since hrtimers have a fixed rate, we can do a static freq->period
10474 : * mapping and avoid the whole period adjust feedback stuff.
10475 : */
10476 0 : if (event->attr.freq) {
10477 0 : long freq = event->attr.sample_freq;
10478 :
10479 0 : event->attr.sample_period = NSEC_PER_SEC / freq;
10480 0 : hwc->sample_period = event->attr.sample_period;
10481 0 : local64_set(&hwc->period_left, hwc->sample_period);
10482 0 : hwc->last_period = hwc->sample_period;
10483 0 : event->attr.freq = 0;
10484 : }
10485 : }
10486 :
10487 : /*
10488 : * Software event: cpu wall time clock
10489 : */
10490 :
10491 0 : static void cpu_clock_event_update(struct perf_event *event)
10492 : {
10493 0 : s64 prev;
10494 0 : u64 now;
10495 :
10496 0 : now = local_clock();
10497 0 : prev = local64_xchg(&event->hw.prev_count, now);
10498 0 : local64_add(now - prev, &event->count);
10499 0 : }
10500 :
10501 0 : static void cpu_clock_event_start(struct perf_event *event, int flags)
10502 : {
10503 0 : local64_set(&event->hw.prev_count, local_clock());
10504 0 : perf_swevent_start_hrtimer(event);
10505 0 : }
10506 :
10507 0 : static void cpu_clock_event_stop(struct perf_event *event, int flags)
10508 : {
10509 0 : perf_swevent_cancel_hrtimer(event);
10510 0 : cpu_clock_event_update(event);
10511 0 : }
10512 :
10513 0 : static int cpu_clock_event_add(struct perf_event *event, int flags)
10514 : {
10515 0 : if (flags & PERF_EF_START)
10516 0 : cpu_clock_event_start(event, flags);
10517 0 : perf_event_update_userpage(event);
10518 :
10519 0 : return 0;
10520 : }
10521 :
10522 0 : static void cpu_clock_event_del(struct perf_event *event, int flags)
10523 : {
10524 0 : cpu_clock_event_stop(event, flags);
10525 0 : }
10526 :
10527 0 : static void cpu_clock_event_read(struct perf_event *event)
10528 : {
10529 0 : cpu_clock_event_update(event);
10530 0 : }
10531 :
10532 0 : static int cpu_clock_event_init(struct perf_event *event)
10533 : {
10534 0 : if (event->attr.type != PERF_TYPE_SOFTWARE)
10535 : return -ENOENT;
10536 :
10537 0 : if (event->attr.config != PERF_COUNT_SW_CPU_CLOCK)
10538 : return -ENOENT;
10539 :
10540 : /*
10541 : * no branch sampling for software events
10542 : */
10543 0 : if (has_branch_stack(event))
10544 : return -EOPNOTSUPP;
10545 :
10546 0 : perf_swevent_init_hrtimer(event);
10547 :
10548 0 : return 0;
10549 : }
10550 :
10551 : static struct pmu perf_cpu_clock = {
10552 : .task_ctx_nr = perf_sw_context,
10553 :
10554 : .capabilities = PERF_PMU_CAP_NO_NMI,
10555 :
10556 : .event_init = cpu_clock_event_init,
10557 : .add = cpu_clock_event_add,
10558 : .del = cpu_clock_event_del,
10559 : .start = cpu_clock_event_start,
10560 : .stop = cpu_clock_event_stop,
10561 : .read = cpu_clock_event_read,
10562 : };
10563 :
10564 : /*
10565 : * Software event: task time clock
10566 : */
10567 :
10568 0 : static void task_clock_event_update(struct perf_event *event, u64 now)
10569 : {
10570 0 : u64 prev;
10571 0 : s64 delta;
10572 :
10573 0 : prev = local64_xchg(&event->hw.prev_count, now);
10574 0 : delta = now - prev;
10575 0 : local64_add(delta, &event->count);
10576 0 : }
10577 :
10578 0 : static void task_clock_event_start(struct perf_event *event, int flags)
10579 : {
10580 0 : local64_set(&event->hw.prev_count, event->ctx->time);
10581 0 : perf_swevent_start_hrtimer(event);
10582 0 : }
10583 :
10584 0 : static void task_clock_event_stop(struct perf_event *event, int flags)
10585 : {
10586 0 : perf_swevent_cancel_hrtimer(event);
10587 0 : task_clock_event_update(event, event->ctx->time);
10588 0 : }
10589 :
10590 0 : static int task_clock_event_add(struct perf_event *event, int flags)
10591 : {
10592 0 : if (flags & PERF_EF_START)
10593 0 : task_clock_event_start(event, flags);
10594 0 : perf_event_update_userpage(event);
10595 :
10596 0 : return 0;
10597 : }
10598 :
10599 0 : static void task_clock_event_del(struct perf_event *event, int flags)
10600 : {
10601 0 : task_clock_event_stop(event, PERF_EF_UPDATE);
10602 0 : }
10603 :
10604 0 : static void task_clock_event_read(struct perf_event *event)
10605 : {
10606 0 : u64 now = perf_clock();
10607 0 : u64 delta = now - event->ctx->timestamp;
10608 0 : u64 time = event->ctx->time + delta;
10609 :
10610 0 : task_clock_event_update(event, time);
10611 0 : }
10612 :
10613 0 : static int task_clock_event_init(struct perf_event *event)
10614 : {
10615 0 : if (event->attr.type != PERF_TYPE_SOFTWARE)
10616 : return -ENOENT;
10617 :
10618 0 : if (event->attr.config != PERF_COUNT_SW_TASK_CLOCK)
10619 : return -ENOENT;
10620 :
10621 : /*
10622 : * no branch sampling for software events
10623 : */
10624 0 : if (has_branch_stack(event))
10625 : return -EOPNOTSUPP;
10626 :
10627 0 : perf_swevent_init_hrtimer(event);
10628 :
10629 0 : return 0;
10630 : }
10631 :
10632 : static struct pmu perf_task_clock = {
10633 : .task_ctx_nr = perf_sw_context,
10634 :
10635 : .capabilities = PERF_PMU_CAP_NO_NMI,
10636 :
10637 : .event_init = task_clock_event_init,
10638 : .add = task_clock_event_add,
10639 : .del = task_clock_event_del,
10640 : .start = task_clock_event_start,
10641 : .stop = task_clock_event_stop,
10642 : .read = task_clock_event_read,
10643 : };
10644 :
10645 0 : static void perf_pmu_nop_void(struct pmu *pmu)
10646 : {
10647 0 : }
10648 :
10649 0 : static void perf_pmu_nop_txn(struct pmu *pmu, unsigned int flags)
10650 : {
10651 0 : }
10652 :
10653 0 : static int perf_pmu_nop_int(struct pmu *pmu)
10654 : {
10655 0 : return 0;
10656 : }
10657 :
10658 0 : static int perf_event_nop_int(struct perf_event *event, u64 value)
10659 : {
10660 0 : return 0;
10661 : }
10662 :
10663 : static DEFINE_PER_CPU(unsigned int, nop_txn_flags);
10664 :
10665 0 : static void perf_pmu_start_txn(struct pmu *pmu, unsigned int flags)
10666 : {
10667 0 : __this_cpu_write(nop_txn_flags, flags);
10668 :
10669 0 : if (flags & ~PERF_PMU_TXN_ADD)
10670 : return;
10671 :
10672 0 : perf_pmu_disable(pmu);
10673 : }
10674 :
10675 0 : static int perf_pmu_commit_txn(struct pmu *pmu)
10676 : {
10677 0 : unsigned int flags = __this_cpu_read(nop_txn_flags);
10678 :
10679 0 : __this_cpu_write(nop_txn_flags, 0);
10680 :
10681 0 : if (flags & ~PERF_PMU_TXN_ADD)
10682 : return 0;
10683 :
10684 0 : perf_pmu_enable(pmu);
10685 0 : return 0;
10686 : }
10687 :
10688 0 : static void perf_pmu_cancel_txn(struct pmu *pmu)
10689 : {
10690 0 : unsigned int flags = __this_cpu_read(nop_txn_flags);
10691 :
10692 0 : __this_cpu_write(nop_txn_flags, 0);
10693 :
10694 0 : if (flags & ~PERF_PMU_TXN_ADD)
10695 : return;
10696 :
10697 0 : perf_pmu_enable(pmu);
10698 : }
10699 :
10700 0 : static int perf_event_idx_default(struct perf_event *event)
10701 : {
10702 0 : return 0;
10703 : }
10704 :
10705 : /*
10706 : * Ensures all contexts with the same task_ctx_nr have the same
10707 : * pmu_cpu_context too.
10708 : */
10709 7 : static struct perf_cpu_context __percpu *find_pmu_context(int ctxn)
10710 : {
10711 7 : struct pmu *pmu;
10712 :
10713 7 : if (ctxn < 0)
10714 : return NULL;
10715 :
10716 12 : list_for_each_entry(pmu, &pmus, entry) {
10717 10 : if (pmu->task_ctx_nr == ctxn)
10718 5 : return pmu->pmu_cpu_context;
10719 : }
10720 :
10721 : return NULL;
10722 : }
10723 :
10724 0 : static void free_pmu_context(struct pmu *pmu)
10725 : {
10726 : /*
10727 : * Static contexts such as perf_sw_context have a global lifetime
10728 : * and may be shared between different PMUs. Avoid freeing them
10729 : * when a single PMU is going away.
10730 : */
10731 0 : if (pmu->task_ctx_nr > perf_invalid_context)
10732 : return;
10733 :
10734 0 : free_percpu(pmu->pmu_cpu_context);
10735 : }
10736 :
10737 : /*
10738 : * Let userspace know that this PMU supports address range filtering:
10739 : */
10740 0 : static ssize_t nr_addr_filters_show(struct device *dev,
10741 : struct device_attribute *attr,
10742 : char *page)
10743 : {
10744 0 : struct pmu *pmu = dev_get_drvdata(dev);
10745 :
10746 0 : return snprintf(page, PAGE_SIZE - 1, "%d\n", pmu->nr_addr_filters);
10747 : }
10748 : DEVICE_ATTR_RO(nr_addr_filters);
10749 :
10750 : static struct idr pmu_idr;
10751 :
10752 : static ssize_t
10753 0 : type_show(struct device *dev, struct device_attribute *attr, char *page)
10754 : {
10755 0 : struct pmu *pmu = dev_get_drvdata(dev);
10756 :
10757 0 : return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->type);
10758 : }
10759 : static DEVICE_ATTR_RO(type);
10760 :
10761 : static ssize_t
10762 0 : perf_event_mux_interval_ms_show(struct device *dev,
10763 : struct device_attribute *attr,
10764 : char *page)
10765 : {
10766 0 : struct pmu *pmu = dev_get_drvdata(dev);
10767 :
10768 0 : return snprintf(page, PAGE_SIZE-1, "%d\n", pmu->hrtimer_interval_ms);
10769 : }
10770 :
10771 : static DEFINE_MUTEX(mux_interval_mutex);
10772 :
10773 : static ssize_t
10774 0 : perf_event_mux_interval_ms_store(struct device *dev,
10775 : struct device_attribute *attr,
10776 : const char *buf, size_t count)
10777 : {
10778 0 : struct pmu *pmu = dev_get_drvdata(dev);
10779 0 : int timer, cpu, ret;
10780 :
10781 0 : ret = kstrtoint(buf, 0, &timer);
10782 0 : if (ret)
10783 0 : return ret;
10784 :
10785 0 : if (timer < 1)
10786 : return -EINVAL;
10787 :
10788 : /* same value, noting to do */
10789 0 : if (timer == pmu->hrtimer_interval_ms)
10790 0 : return count;
10791 :
10792 0 : mutex_lock(&mux_interval_mutex);
10793 0 : pmu->hrtimer_interval_ms = timer;
10794 :
10795 : /* update all cpuctx for this PMU */
10796 0 : cpus_read_lock();
10797 0 : for_each_online_cpu(cpu) {
10798 0 : struct perf_cpu_context *cpuctx;
10799 0 : cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
10800 0 : cpuctx->hrtimer_interval = ns_to_ktime(NSEC_PER_MSEC * timer);
10801 :
10802 0 : cpu_function_call(cpu,
10803 : (remote_function_f)perf_mux_hrtimer_restart, cpuctx);
10804 : }
10805 0 : cpus_read_unlock();
10806 0 : mutex_unlock(&mux_interval_mutex);
10807 :
10808 0 : return count;
10809 : }
10810 : static DEVICE_ATTR_RW(perf_event_mux_interval_ms);
10811 :
10812 : static struct attribute *pmu_dev_attrs[] = {
10813 : &dev_attr_type.attr,
10814 : &dev_attr_perf_event_mux_interval_ms.attr,
10815 : NULL,
10816 : };
10817 : ATTRIBUTE_GROUPS(pmu_dev);
10818 :
10819 : static int pmu_bus_running;
10820 : static struct bus_type pmu_bus = {
10821 : .name = "event_source",
10822 : .dev_groups = pmu_dev_groups,
10823 : };
10824 :
10825 0 : static void pmu_dev_release(struct device *dev)
10826 : {
10827 0 : kfree(dev);
10828 0 : }
10829 :
10830 5 : static int pmu_dev_alloc(struct pmu *pmu)
10831 : {
10832 5 : int ret = -ENOMEM;
10833 :
10834 5 : pmu->dev = kzalloc(sizeof(struct device), GFP_KERNEL);
10835 5 : if (!pmu->dev)
10836 0 : goto out;
10837 :
10838 5 : pmu->dev->groups = pmu->attr_groups;
10839 5 : device_initialize(pmu->dev);
10840 5 : ret = dev_set_name(pmu->dev, "%s", pmu->name);
10841 5 : if (ret)
10842 0 : goto free_dev;
10843 :
10844 5 : dev_set_drvdata(pmu->dev, pmu);
10845 5 : pmu->dev->bus = &pmu_bus;
10846 5 : pmu->dev->release = pmu_dev_release;
10847 5 : ret = device_add(pmu->dev);
10848 5 : if (ret)
10849 0 : goto free_dev;
10850 :
10851 : /* For PMUs with address filters, throw in an extra attribute: */
10852 5 : if (pmu->nr_addr_filters)
10853 0 : ret = device_create_file(pmu->dev, &dev_attr_nr_addr_filters);
10854 :
10855 5 : if (ret)
10856 0 : goto del_dev;
10857 :
10858 5 : if (pmu->attr_update)
10859 2 : ret = sysfs_update_groups(&pmu->dev->kobj, pmu->attr_update);
10860 :
10861 5 : if (ret)
10862 0 : goto del_dev;
10863 :
10864 5 : out:
10865 5 : return ret;
10866 :
10867 0 : del_dev:
10868 0 : device_del(pmu->dev);
10869 :
10870 0 : free_dev:
10871 0 : put_device(pmu->dev);
10872 0 : goto out;
10873 : }
10874 :
10875 : static struct lock_class_key cpuctx_mutex;
10876 : static struct lock_class_key cpuctx_lock;
10877 :
10878 7 : int perf_pmu_register(struct pmu *pmu, const char *name, int type)
10879 : {
10880 7 : int cpu, ret, max = PERF_TYPE_MAX;
10881 :
10882 7 : mutex_lock(&pmus_lock);
10883 7 : ret = -ENOMEM;
10884 7 : pmu->pmu_disable_count = alloc_percpu(int);
10885 7 : if (!pmu->pmu_disable_count)
10886 0 : goto unlock;
10887 :
10888 7 : pmu->type = -1;
10889 7 : if (!name)
10890 2 : goto skip_type;
10891 5 : pmu->name = name;
10892 :
10893 5 : if (type != PERF_TYPE_SOFTWARE) {
10894 4 : if (type >= 0)
10895 3 : max = type;
10896 :
10897 4 : ret = idr_alloc(&pmu_idr, pmu, max, 0, GFP_KERNEL);
10898 4 : if (ret < 0)
10899 0 : goto free_pdc;
10900 :
10901 4 : WARN_ON(type >= 0 && ret != type);
10902 :
10903 : type = ret;
10904 : }
10905 5 : pmu->type = type;
10906 :
10907 5 : if (pmu_bus_running) {
10908 0 : ret = pmu_dev_alloc(pmu);
10909 0 : if (ret)
10910 0 : goto free_idr;
10911 : }
10912 :
10913 5 : skip_type:
10914 7 : if (pmu->task_ctx_nr == perf_hw_context) {
10915 1 : static int hw_context_taken = 0;
10916 :
10917 : /*
10918 : * Other than systems with heterogeneous CPUs, it never makes
10919 : * sense for two PMUs to share perf_hw_context. PMUs which are
10920 : * uncore must use perf_invalid_context.
10921 : */
10922 2 : if (WARN_ON_ONCE(hw_context_taken &&
10923 : !(pmu->capabilities & PERF_PMU_CAP_HETEROGENEOUS_CPUS)))
10924 0 : pmu->task_ctx_nr = perf_invalid_context;
10925 :
10926 1 : hw_context_taken = 1;
10927 : }
10928 :
10929 7 : pmu->pmu_cpu_context = find_pmu_context(pmu->task_ctx_nr);
10930 7 : if (pmu->pmu_cpu_context)
10931 5 : goto got_cpu_context;
10932 :
10933 2 : ret = -ENOMEM;
10934 2 : pmu->pmu_cpu_context = alloc_percpu(struct perf_cpu_context);
10935 2 : if (!pmu->pmu_cpu_context)
10936 0 : goto free_dev;
10937 :
10938 10 : for_each_possible_cpu(cpu) {
10939 8 : struct perf_cpu_context *cpuctx;
10940 :
10941 8 : cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
10942 8 : __perf_event_init_context(&cpuctx->ctx);
10943 8 : lockdep_set_class(&cpuctx->ctx.mutex, &cpuctx_mutex);
10944 8 : lockdep_set_class(&cpuctx->ctx.lock, &cpuctx_lock);
10945 8 : cpuctx->ctx.pmu = pmu;
10946 8 : cpuctx->online = cpumask_test_cpu(cpu, perf_online_mask);
10947 :
10948 8 : __perf_mux_hrtimer_init(cpuctx, cpu);
10949 :
10950 8 : cpuctx->heap_size = ARRAY_SIZE(cpuctx->heap_default);
10951 8 : cpuctx->heap = cpuctx->heap_default;
10952 : }
10953 :
10954 2 : got_cpu_context:
10955 7 : if (!pmu->start_txn) {
10956 6 : if (pmu->pmu_enable) {
10957 : /*
10958 : * If we have pmu_enable/pmu_disable calls, install
10959 : * transaction stubs that use that to try and batch
10960 : * hardware accesses.
10961 : */
10962 0 : pmu->start_txn = perf_pmu_start_txn;
10963 0 : pmu->commit_txn = perf_pmu_commit_txn;
10964 0 : pmu->cancel_txn = perf_pmu_cancel_txn;
10965 : } else {
10966 6 : pmu->start_txn = perf_pmu_nop_txn;
10967 6 : pmu->commit_txn = perf_pmu_nop_int;
10968 6 : pmu->cancel_txn = perf_pmu_nop_void;
10969 : }
10970 : }
10971 :
10972 7 : if (!pmu->pmu_enable) {
10973 6 : pmu->pmu_enable = perf_pmu_nop_void;
10974 6 : pmu->pmu_disable = perf_pmu_nop_void;
10975 : }
10976 :
10977 7 : if (!pmu->check_period)
10978 6 : pmu->check_period = perf_event_nop_int;
10979 :
10980 7 : if (!pmu->event_idx)
10981 6 : pmu->event_idx = perf_event_idx_default;
10982 :
10983 : /*
10984 : * Ensure the TYPE_SOFTWARE PMUs are at the head of the list,
10985 : * since these cannot be in the IDR. This way the linear search
10986 : * is fast, provided a valid software event is provided.
10987 : */
10988 7 : if (type == PERF_TYPE_SOFTWARE || !name)
10989 3 : list_add_rcu(&pmu->entry, &pmus);
10990 : else
10991 4 : list_add_tail_rcu(&pmu->entry, &pmus);
10992 :
10993 7 : atomic_set(&pmu->exclusive_cnt, 0);
10994 7 : ret = 0;
10995 7 : unlock:
10996 7 : mutex_unlock(&pmus_lock);
10997 :
10998 7 : return ret;
10999 :
11000 0 : free_dev:
11001 0 : device_del(pmu->dev);
11002 0 : put_device(pmu->dev);
11003 :
11004 0 : free_idr:
11005 0 : if (pmu->type != PERF_TYPE_SOFTWARE)
11006 0 : idr_remove(&pmu_idr, pmu->type);
11007 :
11008 0 : free_pdc:
11009 0 : free_percpu(pmu->pmu_disable_count);
11010 0 : goto unlock;
11011 : }
11012 : EXPORT_SYMBOL_GPL(perf_pmu_register);
11013 :
11014 0 : void perf_pmu_unregister(struct pmu *pmu)
11015 : {
11016 0 : mutex_lock(&pmus_lock);
11017 0 : list_del_rcu(&pmu->entry);
11018 :
11019 : /*
11020 : * We dereference the pmu list under both SRCU and regular RCU, so
11021 : * synchronize against both of those.
11022 : */
11023 0 : synchronize_srcu(&pmus_srcu);
11024 0 : synchronize_rcu();
11025 :
11026 0 : free_percpu(pmu->pmu_disable_count);
11027 0 : if (pmu->type != PERF_TYPE_SOFTWARE)
11028 0 : idr_remove(&pmu_idr, pmu->type);
11029 0 : if (pmu_bus_running) {
11030 0 : if (pmu->nr_addr_filters)
11031 0 : device_remove_file(pmu->dev, &dev_attr_nr_addr_filters);
11032 0 : device_del(pmu->dev);
11033 0 : put_device(pmu->dev);
11034 : }
11035 0 : free_pmu_context(pmu);
11036 0 : mutex_unlock(&pmus_lock);
11037 0 : }
11038 : EXPORT_SYMBOL_GPL(perf_pmu_unregister);
11039 :
11040 0 : static inline bool has_extended_regs(struct perf_event *event)
11041 : {
11042 0 : return (event->attr.sample_regs_user & PERF_REG_EXTENDED_MASK) ||
11043 0 : (event->attr.sample_regs_intr & PERF_REG_EXTENDED_MASK);
11044 : }
11045 :
11046 0 : static int perf_try_init_event(struct pmu *pmu, struct perf_event *event)
11047 : {
11048 0 : struct perf_event_context *ctx = NULL;
11049 0 : int ret;
11050 :
11051 0 : if (!try_module_get(pmu->module))
11052 : return -ENODEV;
11053 :
11054 : /*
11055 : * A number of pmu->event_init() methods iterate the sibling_list to,
11056 : * for example, validate if the group fits on the PMU. Therefore,
11057 : * if this is a sibling event, acquire the ctx->mutex to protect
11058 : * the sibling_list.
11059 : */
11060 0 : if (event->group_leader != event && pmu->task_ctx_nr != perf_sw_context) {
11061 : /*
11062 : * This ctx->mutex can nest when we're called through
11063 : * inheritance. See the perf_event_ctx_lock_nested() comment.
11064 : */
11065 0 : ctx = perf_event_ctx_lock_nested(event->group_leader,
11066 : SINGLE_DEPTH_NESTING);
11067 0 : BUG_ON(!ctx);
11068 : }
11069 :
11070 0 : event->pmu = pmu;
11071 0 : ret = pmu->event_init(event);
11072 :
11073 0 : if (ctx)
11074 0 : perf_event_ctx_unlock(event->group_leader, ctx);
11075 :
11076 0 : if (!ret) {
11077 0 : if (!(pmu->capabilities & PERF_PMU_CAP_EXTENDED_REGS) &&
11078 0 : has_extended_regs(event))
11079 0 : ret = -EOPNOTSUPP;
11080 :
11081 0 : if (pmu->capabilities & PERF_PMU_CAP_NO_EXCLUDE &&
11082 0 : event_has_any_exclude_flag(event))
11083 : ret = -EINVAL;
11084 :
11085 0 : if (ret && event->destroy)
11086 0 : event->destroy(event);
11087 : }
11088 :
11089 0 : if (ret)
11090 0 : module_put(pmu->module);
11091 :
11092 0 : return ret;
11093 : }
11094 :
11095 0 : static struct pmu *perf_init_event(struct perf_event *event)
11096 : {
11097 0 : int idx, type, ret;
11098 0 : struct pmu *pmu;
11099 :
11100 0 : idx = srcu_read_lock(&pmus_srcu);
11101 :
11102 : /* Try parent's PMU first: */
11103 0 : if (event->parent && event->parent->pmu) {
11104 0 : pmu = event->parent->pmu;
11105 0 : ret = perf_try_init_event(pmu, event);
11106 0 : if (!ret)
11107 0 : goto unlock;
11108 : }
11109 :
11110 : /*
11111 : * PERF_TYPE_HARDWARE and PERF_TYPE_HW_CACHE
11112 : * are often aliases for PERF_TYPE_RAW.
11113 : */
11114 0 : type = event->attr.type;
11115 0 : if (type == PERF_TYPE_HARDWARE || type == PERF_TYPE_HW_CACHE)
11116 0 : type = PERF_TYPE_RAW;
11117 :
11118 0 : again:
11119 0 : rcu_read_lock();
11120 0 : pmu = idr_find(&pmu_idr, type);
11121 0 : rcu_read_unlock();
11122 0 : if (pmu) {
11123 0 : ret = perf_try_init_event(pmu, event);
11124 0 : if (ret == -ENOENT && event->attr.type != type) {
11125 0 : type = event->attr.type;
11126 0 : goto again;
11127 : }
11128 :
11129 0 : if (ret)
11130 0 : pmu = ERR_PTR(ret);
11131 :
11132 0 : goto unlock;
11133 : }
11134 :
11135 0 : list_for_each_entry_rcu(pmu, &pmus, entry, lockdep_is_held(&pmus_srcu)) {
11136 0 : ret = perf_try_init_event(pmu, event);
11137 0 : if (!ret)
11138 0 : goto unlock;
11139 :
11140 0 : if (ret != -ENOENT) {
11141 0 : pmu = ERR_PTR(ret);
11142 0 : goto unlock;
11143 : }
11144 : }
11145 0 : pmu = ERR_PTR(-ENOENT);
11146 0 : unlock:
11147 0 : srcu_read_unlock(&pmus_srcu, idx);
11148 :
11149 0 : return pmu;
11150 : }
11151 :
11152 0 : static void attach_sb_event(struct perf_event *event)
11153 : {
11154 0 : struct pmu_event_list *pel = per_cpu_ptr(&pmu_sb_events, event->cpu);
11155 :
11156 0 : raw_spin_lock(&pel->lock);
11157 0 : list_add_rcu(&event->sb_list, &pel->list);
11158 0 : raw_spin_unlock(&pel->lock);
11159 0 : }
11160 :
11161 : /*
11162 : * We keep a list of all !task (and therefore per-cpu) events
11163 : * that need to receive side-band records.
11164 : *
11165 : * This avoids having to scan all the various PMU per-cpu contexts
11166 : * looking for them.
11167 : */
11168 0 : static void account_pmu_sb_event(struct perf_event *event)
11169 : {
11170 0 : if (is_sb_event(event))
11171 0 : attach_sb_event(event);
11172 0 : }
11173 :
11174 0 : static void account_event_cpu(struct perf_event *event, int cpu)
11175 : {
11176 0 : if (event->parent)
11177 : return;
11178 :
11179 0 : if (is_cgroup_event(event))
11180 0 : atomic_inc(&per_cpu(perf_cgroup_events, cpu));
11181 : }
11182 :
11183 : /* Freq events need the tick to stay alive (see perf_event_task_tick). */
11184 : static void account_freq_event_nohz(void)
11185 : {
11186 : #ifdef CONFIG_NO_HZ_FULL
11187 : /* Lock so we don't race with concurrent unaccount */
11188 : spin_lock(&nr_freq_lock);
11189 : if (atomic_inc_return(&nr_freq_events) == 1)
11190 : tick_nohz_dep_set(TICK_DEP_BIT_PERF_EVENTS);
11191 : spin_unlock(&nr_freq_lock);
11192 : #endif
11193 : }
11194 :
11195 0 : static void account_freq_event(void)
11196 : {
11197 0 : if (tick_nohz_full_enabled())
11198 : account_freq_event_nohz();
11199 : else
11200 0 : atomic_inc(&nr_freq_events);
11201 0 : }
11202 :
11203 :
11204 0 : static void account_event(struct perf_event *event)
11205 : {
11206 0 : bool inc = false;
11207 :
11208 0 : if (event->parent)
11209 : return;
11210 :
11211 0 : if (event->attach_state & (PERF_ATTACH_TASK | PERF_ATTACH_SCHED_CB))
11212 0 : inc = true;
11213 0 : if (event->attr.mmap || event->attr.mmap_data)
11214 0 : atomic_inc(&nr_mmap_events);
11215 0 : if (event->attr.build_id)
11216 0 : atomic_inc(&nr_build_id_events);
11217 0 : if (event->attr.comm)
11218 0 : atomic_inc(&nr_comm_events);
11219 0 : if (event->attr.namespaces)
11220 0 : atomic_inc(&nr_namespaces_events);
11221 0 : if (event->attr.cgroup)
11222 0 : atomic_inc(&nr_cgroup_events);
11223 0 : if (event->attr.task)
11224 0 : atomic_inc(&nr_task_events);
11225 0 : if (event->attr.freq)
11226 0 : account_freq_event();
11227 0 : if (event->attr.context_switch) {
11228 0 : atomic_inc(&nr_switch_events);
11229 0 : inc = true;
11230 : }
11231 0 : if (has_branch_stack(event))
11232 0 : inc = true;
11233 0 : if (is_cgroup_event(event))
11234 : inc = true;
11235 0 : if (event->attr.ksymbol)
11236 0 : atomic_inc(&nr_ksymbol_events);
11237 0 : if (event->attr.bpf_event)
11238 0 : atomic_inc(&nr_bpf_events);
11239 0 : if (event->attr.text_poke)
11240 0 : atomic_inc(&nr_text_poke_events);
11241 :
11242 0 : if (inc) {
11243 : /*
11244 : * We need the mutex here because static_branch_enable()
11245 : * must complete *before* the perf_sched_count increment
11246 : * becomes visible.
11247 : */
11248 0 : if (atomic_inc_not_zero(&perf_sched_count))
11249 0 : goto enabled;
11250 :
11251 0 : mutex_lock(&perf_sched_mutex);
11252 0 : if (!atomic_read(&perf_sched_count)) {
11253 0 : static_branch_enable(&perf_sched_events);
11254 : /*
11255 : * Guarantee that all CPUs observe they key change and
11256 : * call the perf scheduling hooks before proceeding to
11257 : * install events that need them.
11258 : */
11259 0 : synchronize_rcu();
11260 : }
11261 : /*
11262 : * Now that we have waited for the sync_sched(), allow further
11263 : * increments to by-pass the mutex.
11264 : */
11265 0 : atomic_inc(&perf_sched_count);
11266 0 : mutex_unlock(&perf_sched_mutex);
11267 : }
11268 0 : enabled:
11269 :
11270 0 : account_event_cpu(event, event->cpu);
11271 :
11272 0 : account_pmu_sb_event(event);
11273 : }
11274 :
11275 : /*
11276 : * Allocate and initialize an event structure
11277 : */
11278 : static struct perf_event *
11279 0 : perf_event_alloc(struct perf_event_attr *attr, int cpu,
11280 : struct task_struct *task,
11281 : struct perf_event *group_leader,
11282 : struct perf_event *parent_event,
11283 : perf_overflow_handler_t overflow_handler,
11284 : void *context, int cgroup_fd)
11285 : {
11286 0 : struct pmu *pmu;
11287 0 : struct perf_event *event;
11288 0 : struct hw_perf_event *hwc;
11289 0 : long err = -EINVAL;
11290 :
11291 0 : if ((unsigned)cpu >= nr_cpu_ids) {
11292 0 : if (!task || cpu != -1)
11293 0 : return ERR_PTR(-EINVAL);
11294 : }
11295 :
11296 0 : event = kzalloc(sizeof(*event), GFP_KERNEL);
11297 0 : if (!event)
11298 0 : return ERR_PTR(-ENOMEM);
11299 :
11300 : /*
11301 : * Single events are their own group leaders, with an
11302 : * empty sibling list:
11303 : */
11304 0 : if (!group_leader)
11305 0 : group_leader = event;
11306 :
11307 0 : mutex_init(&event->child_mutex);
11308 0 : INIT_LIST_HEAD(&event->child_list);
11309 :
11310 0 : INIT_LIST_HEAD(&event->event_entry);
11311 0 : INIT_LIST_HEAD(&event->sibling_list);
11312 0 : INIT_LIST_HEAD(&event->active_list);
11313 0 : init_event_group(event);
11314 0 : INIT_LIST_HEAD(&event->rb_entry);
11315 0 : INIT_LIST_HEAD(&event->active_entry);
11316 0 : INIT_LIST_HEAD(&event->addr_filters.list);
11317 0 : INIT_HLIST_NODE(&event->hlist_entry);
11318 :
11319 :
11320 0 : init_waitqueue_head(&event->waitq);
11321 0 : event->pending_disable = -1;
11322 0 : init_irq_work(&event->pending, perf_pending_event);
11323 :
11324 0 : mutex_init(&event->mmap_mutex);
11325 0 : raw_spin_lock_init(&event->addr_filters.lock);
11326 :
11327 0 : atomic_long_set(&event->refcount, 1);
11328 0 : event->cpu = cpu;
11329 0 : event->attr = *attr;
11330 0 : event->group_leader = group_leader;
11331 0 : event->pmu = NULL;
11332 0 : event->oncpu = -1;
11333 :
11334 0 : event->parent = parent_event;
11335 :
11336 0 : event->ns = get_pid_ns(task_active_pid_ns(current));
11337 0 : event->id = atomic64_inc_return(&perf_event_id);
11338 :
11339 0 : event->state = PERF_EVENT_STATE_INACTIVE;
11340 :
11341 0 : if (task) {
11342 0 : event->attach_state = PERF_ATTACH_TASK;
11343 : /*
11344 : * XXX pmu::event_init needs to know what task to account to
11345 : * and we cannot use the ctx information because we need the
11346 : * pmu before we get a ctx.
11347 : */
11348 0 : event->hw.target = get_task_struct(task);
11349 : }
11350 :
11351 0 : event->clock = &local_clock;
11352 0 : if (parent_event)
11353 0 : event->clock = parent_event->clock;
11354 :
11355 0 : if (!overflow_handler && parent_event) {
11356 0 : overflow_handler = parent_event->overflow_handler;
11357 0 : context = parent_event->overflow_handler_context;
11358 : #if defined(CONFIG_BPF_SYSCALL) && defined(CONFIG_EVENT_TRACING)
11359 : if (overflow_handler == bpf_overflow_handler) {
11360 : struct bpf_prog *prog = parent_event->prog;
11361 :
11362 : bpf_prog_inc(prog);
11363 : event->prog = prog;
11364 : event->orig_overflow_handler =
11365 : parent_event->orig_overflow_handler;
11366 : }
11367 : #endif
11368 : }
11369 :
11370 0 : if (overflow_handler) {
11371 0 : event->overflow_handler = overflow_handler;
11372 0 : event->overflow_handler_context = context;
11373 0 : } else if (is_write_backward(event)){
11374 0 : event->overflow_handler = perf_event_output_backward;
11375 0 : event->overflow_handler_context = NULL;
11376 : } else {
11377 0 : event->overflow_handler = perf_event_output_forward;
11378 0 : event->overflow_handler_context = NULL;
11379 : }
11380 :
11381 0 : perf_event__state_init(event);
11382 :
11383 0 : pmu = NULL;
11384 :
11385 0 : hwc = &event->hw;
11386 0 : hwc->sample_period = attr->sample_period;
11387 0 : if (attr->freq && attr->sample_freq)
11388 0 : hwc->sample_period = 1;
11389 0 : hwc->last_period = hwc->sample_period;
11390 :
11391 0 : local64_set(&hwc->period_left, hwc->sample_period);
11392 :
11393 : /*
11394 : * We currently do not support PERF_SAMPLE_READ on inherited events.
11395 : * See perf_output_read().
11396 : */
11397 0 : if (attr->inherit && (attr->sample_type & PERF_SAMPLE_READ))
11398 0 : goto err_ns;
11399 :
11400 0 : if (!has_branch_stack(event))
11401 0 : event->attr.branch_sample_type = 0;
11402 :
11403 0 : pmu = perf_init_event(event);
11404 0 : if (IS_ERR(pmu)) {
11405 0 : err = PTR_ERR(pmu);
11406 0 : goto err_ns;
11407 : }
11408 :
11409 : /*
11410 : * Disallow uncore-cgroup events, they don't make sense as the cgroup will
11411 : * be different on other CPUs in the uncore mask.
11412 : */
11413 0 : if (pmu->task_ctx_nr == perf_invalid_context && cgroup_fd != -1) {
11414 0 : err = -EINVAL;
11415 0 : goto err_pmu;
11416 : }
11417 :
11418 0 : if (event->attr.aux_output &&
11419 0 : !(pmu->capabilities & PERF_PMU_CAP_AUX_OUTPUT)) {
11420 0 : err = -EOPNOTSUPP;
11421 0 : goto err_pmu;
11422 : }
11423 :
11424 0 : if (cgroup_fd != -1) {
11425 0 : err = perf_cgroup_connect(cgroup_fd, event, attr, group_leader);
11426 0 : if (err)
11427 0 : goto err_pmu;
11428 : }
11429 :
11430 0 : err = exclusive_event_init(event);
11431 0 : if (err)
11432 0 : goto err_pmu;
11433 :
11434 0 : if (has_addr_filter(event)) {
11435 0 : event->addr_filter_ranges = kcalloc(pmu->nr_addr_filters,
11436 : sizeof(struct perf_addr_filter_range),
11437 : GFP_KERNEL);
11438 0 : if (!event->addr_filter_ranges) {
11439 0 : err = -ENOMEM;
11440 0 : goto err_per_task;
11441 : }
11442 :
11443 : /*
11444 : * Clone the parent's vma offsets: they are valid until exec()
11445 : * even if the mm is not shared with the parent.
11446 : */
11447 0 : if (event->parent) {
11448 0 : struct perf_addr_filters_head *ifh = perf_event_addr_filters(event);
11449 :
11450 0 : raw_spin_lock_irq(&ifh->lock);
11451 0 : memcpy(event->addr_filter_ranges,
11452 0 : event->parent->addr_filter_ranges,
11453 0 : pmu->nr_addr_filters * sizeof(struct perf_addr_filter_range));
11454 0 : raw_spin_unlock_irq(&ifh->lock);
11455 : }
11456 :
11457 : /* force hw sync on the address filters */
11458 0 : event->addr_filters_gen = 1;
11459 : }
11460 :
11461 0 : if (!event->parent) {
11462 0 : if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN) {
11463 0 : err = get_callchain_buffers(attr->sample_max_stack);
11464 0 : if (err)
11465 0 : goto err_addr_filters;
11466 : }
11467 : }
11468 :
11469 0 : err = security_perf_event_alloc(event);
11470 0 : if (err)
11471 0 : goto err_callchain_buffer;
11472 :
11473 : /* symmetric to unaccount_event() in _free_event() */
11474 0 : account_event(event);
11475 :
11476 0 : return event;
11477 :
11478 0 : err_callchain_buffer:
11479 0 : if (!event->parent) {
11480 0 : if (event->attr.sample_type & PERF_SAMPLE_CALLCHAIN)
11481 0 : put_callchain_buffers();
11482 : }
11483 0 : err_addr_filters:
11484 0 : kfree(event->addr_filter_ranges);
11485 :
11486 0 : err_per_task:
11487 0 : exclusive_event_destroy(event);
11488 :
11489 0 : err_pmu:
11490 0 : if (is_cgroup_event(event))
11491 0 : perf_detach_cgroup(event);
11492 0 : if (event->destroy)
11493 0 : event->destroy(event);
11494 0 : module_put(pmu->module);
11495 0 : err_ns:
11496 0 : if (event->ns)
11497 0 : put_pid_ns(event->ns);
11498 0 : if (event->hw.target)
11499 0 : put_task_struct(event->hw.target);
11500 0 : kfree(event);
11501 :
11502 0 : return ERR_PTR(err);
11503 : }
11504 :
11505 0 : static int perf_copy_attr(struct perf_event_attr __user *uattr,
11506 : struct perf_event_attr *attr)
11507 : {
11508 0 : u32 size;
11509 0 : int ret;
11510 :
11511 : /* Zero the full structure, so that a short copy will be nice. */
11512 0 : memset(attr, 0, sizeof(*attr));
11513 :
11514 0 : ret = get_user(size, &uattr->size);
11515 0 : if (ret)
11516 : return ret;
11517 :
11518 : /* ABI compatibility quirk: */
11519 0 : if (!size)
11520 0 : size = PERF_ATTR_SIZE_VER0;
11521 0 : if (size < PERF_ATTR_SIZE_VER0 || size > PAGE_SIZE)
11522 0 : goto err_size;
11523 :
11524 0 : ret = copy_struct_from_user(attr, sizeof(*attr), uattr, size);
11525 0 : if (ret) {
11526 0 : if (ret == -E2BIG)
11527 0 : goto err_size;
11528 : return ret;
11529 : }
11530 :
11531 0 : attr->size = size;
11532 :
11533 0 : if (attr->__reserved_1 || attr->__reserved_2 || attr->__reserved_3)
11534 : return -EINVAL;
11535 :
11536 0 : if (attr->sample_type & ~(PERF_SAMPLE_MAX-1))
11537 : return -EINVAL;
11538 :
11539 0 : if (attr->read_format & ~(PERF_FORMAT_MAX-1))
11540 : return -EINVAL;
11541 :
11542 0 : if (attr->sample_type & PERF_SAMPLE_BRANCH_STACK) {
11543 0 : u64 mask = attr->branch_sample_type;
11544 :
11545 : /* only using defined bits */
11546 0 : if (mask & ~(PERF_SAMPLE_BRANCH_MAX-1))
11547 : return -EINVAL;
11548 :
11549 : /* at least one branch bit must be set */
11550 0 : if (!(mask & ~PERF_SAMPLE_BRANCH_PLM_ALL))
11551 : return -EINVAL;
11552 :
11553 : /* propagate priv level, when not set for branch */
11554 0 : if (!(mask & PERF_SAMPLE_BRANCH_PLM_ALL)) {
11555 :
11556 : /* exclude_kernel checked on syscall entry */
11557 0 : if (!attr->exclude_kernel)
11558 0 : mask |= PERF_SAMPLE_BRANCH_KERNEL;
11559 :
11560 0 : if (!attr->exclude_user)
11561 0 : mask |= PERF_SAMPLE_BRANCH_USER;
11562 :
11563 0 : if (!attr->exclude_hv)
11564 0 : mask |= PERF_SAMPLE_BRANCH_HV;
11565 : /*
11566 : * adjust user setting (for HW filter setup)
11567 : */
11568 0 : attr->branch_sample_type = mask;
11569 : }
11570 : /* privileged levels capture (kernel, hv): check permissions */
11571 0 : if (mask & PERF_SAMPLE_BRANCH_PERM_PLM) {
11572 0 : ret = perf_allow_kernel(attr);
11573 0 : if (ret)
11574 : return ret;
11575 : }
11576 : }
11577 :
11578 0 : if (attr->sample_type & PERF_SAMPLE_REGS_USER) {
11579 0 : ret = perf_reg_validate(attr->sample_regs_user);
11580 0 : if (ret)
11581 : return ret;
11582 : }
11583 :
11584 0 : if (attr->sample_type & PERF_SAMPLE_STACK_USER) {
11585 0 : if (!arch_perf_have_user_stack_dump())
11586 : return -ENOSYS;
11587 :
11588 : /*
11589 : * We have __u32 type for the size, but so far
11590 : * we can only use __u16 as maximum due to the
11591 : * __u16 sample size limit.
11592 : */
11593 0 : if (attr->sample_stack_user >= USHRT_MAX)
11594 : return -EINVAL;
11595 0 : else if (!IS_ALIGNED(attr->sample_stack_user, sizeof(u64)))
11596 : return -EINVAL;
11597 : }
11598 :
11599 0 : if (!attr->sample_max_stack)
11600 0 : attr->sample_max_stack = sysctl_perf_event_max_stack;
11601 :
11602 0 : if (attr->sample_type & PERF_SAMPLE_REGS_INTR)
11603 0 : ret = perf_reg_validate(attr->sample_regs_intr);
11604 :
11605 : #ifndef CONFIG_CGROUP_PERF
11606 0 : if (attr->sample_type & PERF_SAMPLE_CGROUP)
11607 : return -EINVAL;
11608 : #endif
11609 0 : if ((attr->sample_type & PERF_SAMPLE_WEIGHT) &&
11610 : (attr->sample_type & PERF_SAMPLE_WEIGHT_STRUCT))
11611 0 : return -EINVAL;
11612 :
11613 0 : out:
11614 : return ret;
11615 :
11616 0 : err_size:
11617 0 : put_user(sizeof(*attr), &uattr->size);
11618 0 : ret = -E2BIG;
11619 0 : goto out;
11620 : }
11621 :
11622 : static int
11623 0 : perf_event_set_output(struct perf_event *event, struct perf_event *output_event)
11624 : {
11625 0 : struct perf_buffer *rb = NULL;
11626 0 : int ret = -EINVAL;
11627 :
11628 0 : if (!output_event)
11629 0 : goto set;
11630 :
11631 : /* don't allow circular references */
11632 0 : if (event == output_event)
11633 0 : goto out;
11634 :
11635 : /*
11636 : * Don't allow cross-cpu buffers
11637 : */
11638 0 : if (output_event->cpu != event->cpu)
11639 0 : goto out;
11640 :
11641 : /*
11642 : * If its not a per-cpu rb, it must be the same task.
11643 : */
11644 0 : if (output_event->cpu == -1 && output_event->ctx != event->ctx)
11645 0 : goto out;
11646 :
11647 : /*
11648 : * Mixing clocks in the same buffer is trouble you don't need.
11649 : */
11650 0 : if (output_event->clock != event->clock)
11651 0 : goto out;
11652 :
11653 : /*
11654 : * Either writing ring buffer from beginning or from end.
11655 : * Mixing is not allowed.
11656 : */
11657 0 : if (is_write_backward(output_event) != is_write_backward(event))
11658 0 : goto out;
11659 :
11660 : /*
11661 : * If both events generate aux data, they must be on the same PMU
11662 : */
11663 0 : if (has_aux(event) && has_aux(output_event) &&
11664 : event->pmu != output_event->pmu)
11665 0 : goto out;
11666 :
11667 0 : set:
11668 0 : mutex_lock(&event->mmap_mutex);
11669 : /* Can't redirect output if we've got an active mmap() */
11670 0 : if (atomic_read(&event->mmap_count))
11671 0 : goto unlock;
11672 :
11673 0 : if (output_event) {
11674 : /* get the rb we want to redirect to */
11675 0 : rb = ring_buffer_get(output_event);
11676 0 : if (!rb)
11677 0 : goto unlock;
11678 : }
11679 :
11680 0 : ring_buffer_attach(event, rb);
11681 :
11682 0 : ret = 0;
11683 0 : unlock:
11684 0 : mutex_unlock(&event->mmap_mutex);
11685 :
11686 0 : out:
11687 0 : return ret;
11688 : }
11689 :
11690 0 : static void mutex_lock_double(struct mutex *a, struct mutex *b)
11691 : {
11692 0 : if (b < a)
11693 0 : swap(a, b);
11694 :
11695 0 : mutex_lock(a);
11696 0 : mutex_lock_nested(b, SINGLE_DEPTH_NESTING);
11697 0 : }
11698 :
11699 0 : static int perf_event_set_clock(struct perf_event *event, clockid_t clk_id)
11700 : {
11701 0 : bool nmi_safe = false;
11702 :
11703 0 : switch (clk_id) {
11704 0 : case CLOCK_MONOTONIC:
11705 0 : event->clock = &ktime_get_mono_fast_ns;
11706 0 : nmi_safe = true;
11707 0 : break;
11708 :
11709 0 : case CLOCK_MONOTONIC_RAW:
11710 0 : event->clock = &ktime_get_raw_fast_ns;
11711 0 : nmi_safe = true;
11712 0 : break;
11713 :
11714 0 : case CLOCK_REALTIME:
11715 0 : event->clock = &ktime_get_real_ns;
11716 0 : break;
11717 :
11718 0 : case CLOCK_BOOTTIME:
11719 0 : event->clock = &ktime_get_boottime_ns;
11720 0 : break;
11721 :
11722 0 : case CLOCK_TAI:
11723 0 : event->clock = &ktime_get_clocktai_ns;
11724 0 : break;
11725 :
11726 : default:
11727 : return -EINVAL;
11728 : }
11729 :
11730 0 : if (!nmi_safe && !(event->pmu->capabilities & PERF_PMU_CAP_NO_NMI))
11731 0 : return -EINVAL;
11732 :
11733 : return 0;
11734 : }
11735 :
11736 : /*
11737 : * Variation on perf_event_ctx_lock_nested(), except we take two context
11738 : * mutexes.
11739 : */
11740 : static struct perf_event_context *
11741 0 : __perf_event_ctx_lock_double(struct perf_event *group_leader,
11742 : struct perf_event_context *ctx)
11743 : {
11744 0 : struct perf_event_context *gctx;
11745 :
11746 : again:
11747 0 : rcu_read_lock();
11748 0 : gctx = READ_ONCE(group_leader->ctx);
11749 0 : if (!refcount_inc_not_zero(&gctx->refcount)) {
11750 0 : rcu_read_unlock();
11751 0 : goto again;
11752 : }
11753 0 : rcu_read_unlock();
11754 :
11755 0 : mutex_lock_double(&gctx->mutex, &ctx->mutex);
11756 :
11757 0 : if (group_leader->ctx != gctx) {
11758 0 : mutex_unlock(&ctx->mutex);
11759 0 : mutex_unlock(&gctx->mutex);
11760 0 : put_ctx(gctx);
11761 0 : goto again;
11762 : }
11763 :
11764 0 : return gctx;
11765 : }
11766 :
11767 : /**
11768 : * sys_perf_event_open - open a performance event, associate it to a task/cpu
11769 : *
11770 : * @attr_uptr: event_id type attributes for monitoring/sampling
11771 : * @pid: target pid
11772 : * @cpu: target cpu
11773 : * @group_fd: group leader event fd
11774 : */
11775 0 : SYSCALL_DEFINE5(perf_event_open,
11776 : struct perf_event_attr __user *, attr_uptr,
11777 : pid_t, pid, int, cpu, int, group_fd, unsigned long, flags)
11778 : {
11779 0 : struct perf_event *group_leader = NULL, *output_event = NULL;
11780 0 : struct perf_event *event, *sibling;
11781 0 : struct perf_event_attr attr;
11782 0 : struct perf_event_context *ctx, *gctx;
11783 0 : struct file *event_file = NULL;
11784 0 : struct fd group = {NULL, 0};
11785 0 : struct task_struct *task = NULL;
11786 0 : struct pmu *pmu;
11787 0 : int event_fd;
11788 0 : int move_group = 0;
11789 0 : int err;
11790 0 : int f_flags = O_RDWR;
11791 0 : int cgroup_fd = -1;
11792 :
11793 : /* for future expandability... */
11794 0 : if (flags & ~PERF_FLAG_ALL)
11795 : return -EINVAL;
11796 :
11797 : /* Do we allow access to perf_event_open(2) ? */
11798 0 : err = security_perf_event_open(&attr, PERF_SECURITY_OPEN);
11799 0 : if (err)
11800 0 : return err;
11801 :
11802 0 : err = perf_copy_attr(attr_uptr, &attr);
11803 0 : if (err)
11804 0 : return err;
11805 :
11806 0 : if (!attr.exclude_kernel) {
11807 0 : err = perf_allow_kernel(&attr);
11808 0 : if (err)
11809 0 : return err;
11810 : }
11811 :
11812 0 : if (attr.namespaces) {
11813 0 : if (!perfmon_capable())
11814 : return -EACCES;
11815 : }
11816 :
11817 0 : if (attr.freq) {
11818 0 : if (attr.sample_freq > sysctl_perf_event_sample_rate)
11819 : return -EINVAL;
11820 : } else {
11821 0 : if (attr.sample_period & (1ULL << 63))
11822 : return -EINVAL;
11823 : }
11824 :
11825 : /* Only privileged users can get physical addresses */
11826 0 : if ((attr.sample_type & PERF_SAMPLE_PHYS_ADDR)) {
11827 0 : err = perf_allow_kernel(&attr);
11828 0 : if (err)
11829 0 : return err;
11830 : }
11831 :
11832 0 : err = security_locked_down(LOCKDOWN_PERF);
11833 0 : if (err && (attr.sample_type & PERF_SAMPLE_REGS_INTR))
11834 : /* REGS_INTR can leak data, lockdown must prevent this */
11835 0 : return err;
11836 :
11837 0 : err = 0;
11838 :
11839 : /*
11840 : * In cgroup mode, the pid argument is used to pass the fd
11841 : * opened to the cgroup directory in cgroupfs. The cpu argument
11842 : * designates the cpu on which to monitor threads from that
11843 : * cgroup.
11844 : */
11845 0 : if ((flags & PERF_FLAG_PID_CGROUP) && (pid == -1 || cpu == -1))
11846 : return -EINVAL;
11847 :
11848 0 : if (flags & PERF_FLAG_FD_CLOEXEC)
11849 0 : f_flags |= O_CLOEXEC;
11850 :
11851 0 : event_fd = get_unused_fd_flags(f_flags);
11852 0 : if (event_fd < 0)
11853 0 : return event_fd;
11854 :
11855 0 : if (group_fd != -1) {
11856 0 : err = perf_fget_light(group_fd, &group);
11857 0 : if (err)
11858 0 : goto err_fd;
11859 0 : group_leader = group.file->private_data;
11860 0 : if (flags & PERF_FLAG_FD_OUTPUT)
11861 0 : output_event = group_leader;
11862 0 : if (flags & PERF_FLAG_FD_NO_GROUP)
11863 0 : group_leader = NULL;
11864 : }
11865 :
11866 0 : if (pid != -1 && !(flags & PERF_FLAG_PID_CGROUP)) {
11867 0 : task = find_lively_task_by_vpid(pid);
11868 0 : if (IS_ERR(task)) {
11869 0 : err = PTR_ERR(task);
11870 0 : goto err_group_fd;
11871 : }
11872 : }
11873 :
11874 0 : if (task && group_leader &&
11875 0 : group_leader->attr.inherit != attr.inherit) {
11876 0 : err = -EINVAL;
11877 0 : goto err_task;
11878 : }
11879 :
11880 0 : if (flags & PERF_FLAG_PID_CGROUP)
11881 0 : cgroup_fd = pid;
11882 :
11883 0 : event = perf_event_alloc(&attr, cpu, task, group_leader, NULL,
11884 : NULL, NULL, cgroup_fd);
11885 0 : if (IS_ERR(event)) {
11886 0 : err = PTR_ERR(event);
11887 0 : goto err_task;
11888 : }
11889 :
11890 0 : if (is_sampling_event(event)) {
11891 0 : if (event->pmu->capabilities & PERF_PMU_CAP_NO_INTERRUPT) {
11892 0 : err = -EOPNOTSUPP;
11893 0 : goto err_alloc;
11894 : }
11895 : }
11896 :
11897 : /*
11898 : * Special case software events and allow them to be part of
11899 : * any hardware group.
11900 : */
11901 0 : pmu = event->pmu;
11902 :
11903 0 : if (attr.use_clockid) {
11904 0 : err = perf_event_set_clock(event, attr.clockid);
11905 0 : if (err)
11906 0 : goto err_alloc;
11907 : }
11908 :
11909 0 : if (pmu->task_ctx_nr == perf_sw_context)
11910 0 : event->event_caps |= PERF_EV_CAP_SOFTWARE;
11911 :
11912 0 : if (group_leader) {
11913 0 : if (is_software_event(event) &&
11914 0 : !in_software_context(group_leader)) {
11915 : /*
11916 : * If the event is a sw event, but the group_leader
11917 : * is on hw context.
11918 : *
11919 : * Allow the addition of software events to hw
11920 : * groups, this is safe because software events
11921 : * never fail to schedule.
11922 : */
11923 : pmu = group_leader->ctx->pmu;
11924 0 : } else if (!is_software_event(event) &&
11925 0 : is_software_event(group_leader) &&
11926 0 : (group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
11927 : /*
11928 : * In case the group is a pure software group, and we
11929 : * try to add a hardware event, move the whole group to
11930 : * the hardware context.
11931 : */
11932 : move_group = 1;
11933 : }
11934 : }
11935 :
11936 : /*
11937 : * Get the target context (task or percpu):
11938 : */
11939 0 : ctx = find_get_context(pmu, task, event);
11940 0 : if (IS_ERR(ctx)) {
11941 0 : err = PTR_ERR(ctx);
11942 0 : goto err_alloc;
11943 : }
11944 :
11945 : /*
11946 : * Look up the group leader (we will attach this event to it):
11947 : */
11948 0 : if (group_leader) {
11949 0 : err = -EINVAL;
11950 :
11951 : /*
11952 : * Do not allow a recursive hierarchy (this new sibling
11953 : * becoming part of another group-sibling):
11954 : */
11955 0 : if (group_leader->group_leader != group_leader)
11956 0 : goto err_context;
11957 :
11958 : /* All events in a group should have the same clock */
11959 0 : if (group_leader->clock != event->clock)
11960 0 : goto err_context;
11961 :
11962 : /*
11963 : * Make sure we're both events for the same CPU;
11964 : * grouping events for different CPUs is broken; since
11965 : * you can never concurrently schedule them anyhow.
11966 : */
11967 0 : if (group_leader->cpu != event->cpu)
11968 0 : goto err_context;
11969 :
11970 : /*
11971 : * Make sure we're both on the same task, or both
11972 : * per-CPU events.
11973 : */
11974 0 : if (group_leader->ctx->task != ctx->task)
11975 0 : goto err_context;
11976 :
11977 : /*
11978 : * Do not allow to attach to a group in a different task
11979 : * or CPU context. If we're moving SW events, we'll fix
11980 : * this up later, so allow that.
11981 : */
11982 0 : if (!move_group && group_leader->ctx != ctx)
11983 0 : goto err_context;
11984 :
11985 : /*
11986 : * Only a group leader can be exclusive or pinned
11987 : */
11988 0 : if (attr.exclusive || attr.pinned)
11989 0 : goto err_context;
11990 : }
11991 :
11992 0 : if (output_event) {
11993 0 : err = perf_event_set_output(event, output_event);
11994 0 : if (err)
11995 0 : goto err_context;
11996 : }
11997 :
11998 0 : event_file = anon_inode_getfile("[perf_event]", &perf_fops, event,
11999 : f_flags);
12000 0 : if (IS_ERR(event_file)) {
12001 0 : err = PTR_ERR(event_file);
12002 0 : event_file = NULL;
12003 0 : goto err_context;
12004 : }
12005 :
12006 0 : if (task) {
12007 0 : err = down_read_interruptible(&task->signal->exec_update_lock);
12008 0 : if (err)
12009 0 : goto err_file;
12010 :
12011 : /*
12012 : * Preserve ptrace permission check for backwards compatibility.
12013 : *
12014 : * We must hold exec_update_lock across this and any potential
12015 : * perf_install_in_context() call for this new event to
12016 : * serialize against exec() altering our credentials (and the
12017 : * perf_event_exit_task() that could imply).
12018 : */
12019 0 : err = -EACCES;
12020 0 : if (!perfmon_capable() && !ptrace_may_access(task, PTRACE_MODE_READ_REALCREDS))
12021 0 : goto err_cred;
12022 : }
12023 :
12024 0 : if (move_group) {
12025 0 : gctx = __perf_event_ctx_lock_double(group_leader, ctx);
12026 :
12027 0 : if (gctx->task == TASK_TOMBSTONE) {
12028 0 : err = -ESRCH;
12029 0 : goto err_locked;
12030 : }
12031 :
12032 : /*
12033 : * Check if we raced against another sys_perf_event_open() call
12034 : * moving the software group underneath us.
12035 : */
12036 0 : if (!(group_leader->group_caps & PERF_EV_CAP_SOFTWARE)) {
12037 : /*
12038 : * If someone moved the group out from under us, check
12039 : * if this new event wound up on the same ctx, if so
12040 : * its the regular !move_group case, otherwise fail.
12041 : */
12042 0 : if (gctx != ctx) {
12043 0 : err = -EINVAL;
12044 0 : goto err_locked;
12045 : } else {
12046 0 : perf_event_ctx_unlock(group_leader, gctx);
12047 0 : move_group = 0;
12048 : }
12049 : }
12050 :
12051 : /*
12052 : * Failure to create exclusive events returns -EBUSY.
12053 : */
12054 0 : err = -EBUSY;
12055 0 : if (!exclusive_event_installable(group_leader, ctx))
12056 0 : goto err_locked;
12057 :
12058 0 : for_each_sibling_event(sibling, group_leader) {
12059 0 : if (!exclusive_event_installable(sibling, ctx))
12060 0 : goto err_locked;
12061 : }
12062 : } else {
12063 0 : mutex_lock(&ctx->mutex);
12064 : }
12065 :
12066 0 : if (ctx->task == TASK_TOMBSTONE) {
12067 0 : err = -ESRCH;
12068 0 : goto err_locked;
12069 : }
12070 :
12071 0 : if (!perf_event_validate_size(event)) {
12072 0 : err = -E2BIG;
12073 0 : goto err_locked;
12074 : }
12075 :
12076 0 : if (!task) {
12077 : /*
12078 : * Check if the @cpu we're creating an event for is online.
12079 : *
12080 : * We use the perf_cpu_context::ctx::mutex to serialize against
12081 : * the hotplug notifiers. See perf_event_{init,exit}_cpu().
12082 : */
12083 0 : struct perf_cpu_context *cpuctx =
12084 0 : container_of(ctx, struct perf_cpu_context, ctx);
12085 :
12086 0 : if (!cpuctx->online) {
12087 0 : err = -ENODEV;
12088 0 : goto err_locked;
12089 : }
12090 : }
12091 :
12092 0 : if (perf_need_aux_event(event) && !perf_get_aux_event(event, group_leader)) {
12093 0 : err = -EINVAL;
12094 0 : goto err_locked;
12095 : }
12096 :
12097 : /*
12098 : * Must be under the same ctx::mutex as perf_install_in_context(),
12099 : * because we need to serialize with concurrent event creation.
12100 : */
12101 0 : if (!exclusive_event_installable(event, ctx)) {
12102 0 : err = -EBUSY;
12103 0 : goto err_locked;
12104 : }
12105 :
12106 0 : WARN_ON_ONCE(ctx->parent_ctx);
12107 :
12108 : /*
12109 : * This is the point on no return; we cannot fail hereafter. This is
12110 : * where we start modifying current state.
12111 : */
12112 :
12113 0 : if (move_group) {
12114 : /*
12115 : * See perf_event_ctx_lock() for comments on the details
12116 : * of swizzling perf_event::ctx.
12117 : */
12118 0 : perf_remove_from_context(group_leader, 0);
12119 0 : put_ctx(gctx);
12120 :
12121 0 : for_each_sibling_event(sibling, group_leader) {
12122 0 : perf_remove_from_context(sibling, 0);
12123 0 : put_ctx(gctx);
12124 : }
12125 :
12126 : /*
12127 : * Wait for everybody to stop referencing the events through
12128 : * the old lists, before installing it on new lists.
12129 : */
12130 0 : synchronize_rcu();
12131 :
12132 : /*
12133 : * Install the group siblings before the group leader.
12134 : *
12135 : * Because a group leader will try and install the entire group
12136 : * (through the sibling list, which is still in-tact), we can
12137 : * end up with siblings installed in the wrong context.
12138 : *
12139 : * By installing siblings first we NO-OP because they're not
12140 : * reachable through the group lists.
12141 : */
12142 0 : for_each_sibling_event(sibling, group_leader) {
12143 0 : perf_event__state_init(sibling);
12144 0 : perf_install_in_context(ctx, sibling, sibling->cpu);
12145 0 : get_ctx(ctx);
12146 : }
12147 :
12148 : /*
12149 : * Removing from the context ends up with disabled
12150 : * event. What we want here is event in the initial
12151 : * startup state, ready to be add into new context.
12152 : */
12153 0 : perf_event__state_init(group_leader);
12154 0 : perf_install_in_context(ctx, group_leader, group_leader->cpu);
12155 0 : get_ctx(ctx);
12156 : }
12157 :
12158 : /*
12159 : * Precalculate sample_data sizes; do while holding ctx::mutex such
12160 : * that we're serialized against further additions and before
12161 : * perf_install_in_context() which is the point the event is active and
12162 : * can use these values.
12163 : */
12164 0 : perf_event__header_size(event);
12165 0 : perf_event__id_header_size(event);
12166 :
12167 0 : event->owner = current;
12168 :
12169 0 : perf_install_in_context(ctx, event, event->cpu);
12170 0 : perf_unpin_context(ctx);
12171 :
12172 0 : if (move_group)
12173 0 : perf_event_ctx_unlock(group_leader, gctx);
12174 0 : mutex_unlock(&ctx->mutex);
12175 :
12176 0 : if (task) {
12177 0 : up_read(&task->signal->exec_update_lock);
12178 0 : put_task_struct(task);
12179 : }
12180 :
12181 0 : mutex_lock(¤t->perf_event_mutex);
12182 0 : list_add_tail(&event->owner_entry, ¤t->perf_event_list);
12183 0 : mutex_unlock(¤t->perf_event_mutex);
12184 :
12185 : /*
12186 : * Drop the reference on the group_event after placing the
12187 : * new event on the sibling_list. This ensures destruction
12188 : * of the group leader will find the pointer to itself in
12189 : * perf_group_detach().
12190 : */
12191 0 : fdput(group);
12192 0 : fd_install(event_fd, event_file);
12193 0 : return event_fd;
12194 :
12195 0 : err_locked:
12196 0 : if (move_group)
12197 0 : perf_event_ctx_unlock(group_leader, gctx);
12198 0 : mutex_unlock(&ctx->mutex);
12199 0 : err_cred:
12200 0 : if (task)
12201 0 : up_read(&task->signal->exec_update_lock);
12202 0 : err_file:
12203 0 : fput(event_file);
12204 0 : err_context:
12205 0 : perf_unpin_context(ctx);
12206 0 : put_ctx(ctx);
12207 0 : err_alloc:
12208 : /*
12209 : * If event_file is set, the fput() above will have called ->release()
12210 : * and that will take care of freeing the event.
12211 : */
12212 0 : if (!event_file)
12213 0 : free_event(event);
12214 0 : err_task:
12215 0 : if (task)
12216 0 : put_task_struct(task);
12217 0 : err_group_fd:
12218 0 : fdput(group);
12219 0 : err_fd:
12220 0 : put_unused_fd(event_fd);
12221 0 : return err;
12222 : }
12223 :
12224 : /**
12225 : * perf_event_create_kernel_counter
12226 : *
12227 : * @attr: attributes of the counter to create
12228 : * @cpu: cpu in which the counter is bound
12229 : * @task: task to profile (NULL for percpu)
12230 : */
12231 : struct perf_event *
12232 0 : perf_event_create_kernel_counter(struct perf_event_attr *attr, int cpu,
12233 : struct task_struct *task,
12234 : perf_overflow_handler_t overflow_handler,
12235 : void *context)
12236 : {
12237 0 : struct perf_event_context *ctx;
12238 0 : struct perf_event *event;
12239 0 : int err;
12240 :
12241 : /*
12242 : * Grouping is not supported for kernel events, neither is 'AUX',
12243 : * make sure the caller's intentions are adjusted.
12244 : */
12245 0 : if (attr->aux_output)
12246 0 : return ERR_PTR(-EINVAL);
12247 :
12248 0 : event = perf_event_alloc(attr, cpu, task, NULL, NULL,
12249 : overflow_handler, context, -1);
12250 0 : if (IS_ERR(event)) {
12251 0 : err = PTR_ERR(event);
12252 0 : goto err;
12253 : }
12254 :
12255 : /* Mark owner so we could distinguish it from user events. */
12256 0 : event->owner = TASK_TOMBSTONE;
12257 :
12258 : /*
12259 : * Get the target context (task or percpu):
12260 : */
12261 0 : ctx = find_get_context(event->pmu, task, event);
12262 0 : if (IS_ERR(ctx)) {
12263 0 : err = PTR_ERR(ctx);
12264 0 : goto err_free;
12265 : }
12266 :
12267 0 : WARN_ON_ONCE(ctx->parent_ctx);
12268 0 : mutex_lock(&ctx->mutex);
12269 0 : if (ctx->task == TASK_TOMBSTONE) {
12270 0 : err = -ESRCH;
12271 0 : goto err_unlock;
12272 : }
12273 :
12274 0 : if (!task) {
12275 : /*
12276 : * Check if the @cpu we're creating an event for is online.
12277 : *
12278 : * We use the perf_cpu_context::ctx::mutex to serialize against
12279 : * the hotplug notifiers. See perf_event_{init,exit}_cpu().
12280 : */
12281 0 : struct perf_cpu_context *cpuctx =
12282 0 : container_of(ctx, struct perf_cpu_context, ctx);
12283 0 : if (!cpuctx->online) {
12284 0 : err = -ENODEV;
12285 0 : goto err_unlock;
12286 : }
12287 : }
12288 :
12289 0 : if (!exclusive_event_installable(event, ctx)) {
12290 0 : err = -EBUSY;
12291 0 : goto err_unlock;
12292 : }
12293 :
12294 0 : perf_install_in_context(ctx, event, event->cpu);
12295 0 : perf_unpin_context(ctx);
12296 0 : mutex_unlock(&ctx->mutex);
12297 :
12298 0 : return event;
12299 :
12300 0 : err_unlock:
12301 0 : mutex_unlock(&ctx->mutex);
12302 0 : perf_unpin_context(ctx);
12303 0 : put_ctx(ctx);
12304 0 : err_free:
12305 0 : free_event(event);
12306 0 : err:
12307 0 : return ERR_PTR(err);
12308 : }
12309 : EXPORT_SYMBOL_GPL(perf_event_create_kernel_counter);
12310 :
12311 0 : void perf_pmu_migrate_context(struct pmu *pmu, int src_cpu, int dst_cpu)
12312 : {
12313 0 : struct perf_event_context *src_ctx;
12314 0 : struct perf_event_context *dst_ctx;
12315 0 : struct perf_event *event, *tmp;
12316 0 : LIST_HEAD(events);
12317 :
12318 0 : src_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, src_cpu)->ctx;
12319 0 : dst_ctx = &per_cpu_ptr(pmu->pmu_cpu_context, dst_cpu)->ctx;
12320 :
12321 : /*
12322 : * See perf_event_ctx_lock() for comments on the details
12323 : * of swizzling perf_event::ctx.
12324 : */
12325 0 : mutex_lock_double(&src_ctx->mutex, &dst_ctx->mutex);
12326 0 : list_for_each_entry_safe(event, tmp, &src_ctx->event_list,
12327 : event_entry) {
12328 0 : perf_remove_from_context(event, 0);
12329 0 : unaccount_event_cpu(event, src_cpu);
12330 0 : put_ctx(src_ctx);
12331 0 : list_add(&event->migrate_entry, &events);
12332 : }
12333 :
12334 : /*
12335 : * Wait for the events to quiesce before re-instating them.
12336 : */
12337 0 : synchronize_rcu();
12338 :
12339 : /*
12340 : * Re-instate events in 2 passes.
12341 : *
12342 : * Skip over group leaders and only install siblings on this first
12343 : * pass, siblings will not get enabled without a leader, however a
12344 : * leader will enable its siblings, even if those are still on the old
12345 : * context.
12346 : */
12347 0 : list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
12348 0 : if (event->group_leader == event)
12349 0 : continue;
12350 :
12351 0 : list_del(&event->migrate_entry);
12352 0 : if (event->state >= PERF_EVENT_STATE_OFF)
12353 0 : event->state = PERF_EVENT_STATE_INACTIVE;
12354 0 : account_event_cpu(event, dst_cpu);
12355 0 : perf_install_in_context(dst_ctx, event, dst_cpu);
12356 0 : get_ctx(dst_ctx);
12357 : }
12358 :
12359 : /*
12360 : * Once all the siblings are setup properly, install the group leaders
12361 : * to make it go.
12362 : */
12363 0 : list_for_each_entry_safe(event, tmp, &events, migrate_entry) {
12364 0 : list_del(&event->migrate_entry);
12365 0 : if (event->state >= PERF_EVENT_STATE_OFF)
12366 0 : event->state = PERF_EVENT_STATE_INACTIVE;
12367 0 : account_event_cpu(event, dst_cpu);
12368 0 : perf_install_in_context(dst_ctx, event, dst_cpu);
12369 0 : get_ctx(dst_ctx);
12370 : }
12371 0 : mutex_unlock(&dst_ctx->mutex);
12372 0 : mutex_unlock(&src_ctx->mutex);
12373 0 : }
12374 : EXPORT_SYMBOL_GPL(perf_pmu_migrate_context);
12375 :
12376 0 : static void sync_child_event(struct perf_event *child_event,
12377 : struct task_struct *child)
12378 : {
12379 0 : struct perf_event *parent_event = child_event->parent;
12380 0 : u64 child_val;
12381 :
12382 0 : if (child_event->attr.inherit_stat)
12383 0 : perf_event_read_event(child_event, child);
12384 :
12385 0 : child_val = perf_event_count(child_event);
12386 :
12387 : /*
12388 : * Add back the child's count to the parent's count:
12389 : */
12390 0 : atomic64_add(child_val, &parent_event->child_count);
12391 0 : atomic64_add(child_event->total_time_enabled,
12392 : &parent_event->child_total_time_enabled);
12393 0 : atomic64_add(child_event->total_time_running,
12394 : &parent_event->child_total_time_running);
12395 0 : }
12396 :
12397 : static void
12398 0 : perf_event_exit_event(struct perf_event *child_event,
12399 : struct perf_event_context *child_ctx,
12400 : struct task_struct *child)
12401 : {
12402 0 : struct perf_event *parent_event = child_event->parent;
12403 :
12404 : /*
12405 : * Do not destroy the 'original' grouping; because of the context
12406 : * switch optimization the original events could've ended up in a
12407 : * random child task.
12408 : *
12409 : * If we were to destroy the original group, all group related
12410 : * operations would cease to function properly after this random
12411 : * child dies.
12412 : *
12413 : * Do destroy all inherited groups, we don't care about those
12414 : * and being thorough is better.
12415 : */
12416 0 : raw_spin_lock_irq(&child_ctx->lock);
12417 0 : WARN_ON_ONCE(child_ctx->is_active);
12418 :
12419 0 : if (parent_event)
12420 0 : perf_group_detach(child_event);
12421 0 : list_del_event(child_event, child_ctx);
12422 0 : perf_event_set_state(child_event, PERF_EVENT_STATE_EXIT); /* is_event_hup() */
12423 0 : raw_spin_unlock_irq(&child_ctx->lock);
12424 :
12425 : /*
12426 : * Parent events are governed by their filedesc, retain them.
12427 : */
12428 0 : if (!parent_event) {
12429 0 : perf_event_wakeup(child_event);
12430 0 : return;
12431 : }
12432 : /*
12433 : * Child events can be cleaned up.
12434 : */
12435 :
12436 0 : sync_child_event(child_event, child);
12437 :
12438 : /*
12439 : * Remove this event from the parent's list
12440 : */
12441 0 : WARN_ON_ONCE(parent_event->ctx->parent_ctx);
12442 0 : mutex_lock(&parent_event->child_mutex);
12443 0 : list_del_init(&child_event->child_list);
12444 0 : mutex_unlock(&parent_event->child_mutex);
12445 :
12446 : /*
12447 : * Kick perf_poll() for is_event_hup().
12448 : */
12449 0 : perf_event_wakeup(parent_event);
12450 0 : free_event(child_event);
12451 0 : put_event(parent_event);
12452 : }
12453 :
12454 2310 : static void perf_event_exit_task_context(struct task_struct *child, int ctxn)
12455 : {
12456 2310 : struct perf_event_context *child_ctx, *clone_ctx = NULL;
12457 2310 : struct perf_event *child_event, *next;
12458 :
12459 2310 : WARN_ON_ONCE(child != current);
12460 :
12461 2310 : child_ctx = perf_pin_task_context(child, ctxn);
12462 2310 : if (!child_ctx)
12463 : return;
12464 :
12465 : /*
12466 : * In order to reduce the amount of tricky in ctx tear-down, we hold
12467 : * ctx::mutex over the entire thing. This serializes against almost
12468 : * everything that wants to access the ctx.
12469 : *
12470 : * The exception is sys_perf_event_open() /
12471 : * perf_event_create_kernel_count() which does find_get_context()
12472 : * without ctx::mutex (it cannot because of the move_group double mutex
12473 : * lock thing). See the comments in perf_install_in_context().
12474 : */
12475 0 : mutex_lock(&child_ctx->mutex);
12476 :
12477 : /*
12478 : * In a single ctx::lock section, de-schedule the events and detach the
12479 : * context from the task such that we cannot ever get it scheduled back
12480 : * in.
12481 : */
12482 0 : raw_spin_lock_irq(&child_ctx->lock);
12483 0 : task_ctx_sched_out(__get_cpu_context(child_ctx), child_ctx, EVENT_ALL);
12484 :
12485 : /*
12486 : * Now that the context is inactive, destroy the task <-> ctx relation
12487 : * and mark the context dead.
12488 : */
12489 0 : RCU_INIT_POINTER(child->perf_event_ctxp[ctxn], NULL);
12490 0 : put_ctx(child_ctx); /* cannot be last */
12491 0 : WRITE_ONCE(child_ctx->task, TASK_TOMBSTONE);
12492 0 : put_task_struct(current); /* cannot be last */
12493 :
12494 0 : clone_ctx = unclone_ctx(child_ctx);
12495 0 : raw_spin_unlock_irq(&child_ctx->lock);
12496 :
12497 0 : if (clone_ctx)
12498 0 : put_ctx(clone_ctx);
12499 :
12500 : /*
12501 : * Report the task dead after unscheduling the events so that we
12502 : * won't get any samples after PERF_RECORD_EXIT. We can however still
12503 : * get a few PERF_RECORD_READ events.
12504 : */
12505 0 : perf_event_task(child, child_ctx, 0);
12506 :
12507 0 : list_for_each_entry_safe(child_event, next, &child_ctx->event_list, event_entry)
12508 0 : perf_event_exit_event(child_event, child_ctx, child);
12509 :
12510 0 : mutex_unlock(&child_ctx->mutex);
12511 :
12512 0 : put_ctx(child_ctx);
12513 : }
12514 :
12515 : /*
12516 : * When a child task exits, feed back event values to parent events.
12517 : *
12518 : * Can be called with exec_update_lock held when called from
12519 : * setup_new_exec().
12520 : */
12521 1155 : void perf_event_exit_task(struct task_struct *child)
12522 : {
12523 1155 : struct perf_event *event, *tmp;
12524 1155 : int ctxn;
12525 :
12526 1155 : mutex_lock(&child->perf_event_mutex);
12527 1155 : list_for_each_entry_safe(event, tmp, &child->perf_event_list,
12528 : owner_entry) {
12529 0 : list_del_init(&event->owner_entry);
12530 :
12531 : /*
12532 : * Ensure the list deletion is visible before we clear
12533 : * the owner, closes a race against perf_release() where
12534 : * we need to serialize on the owner->perf_event_mutex.
12535 : */
12536 0 : smp_store_release(&event->owner, NULL);
12537 : }
12538 1155 : mutex_unlock(&child->perf_event_mutex);
12539 :
12540 4620 : for_each_task_context_nr(ctxn)
12541 2310 : perf_event_exit_task_context(child, ctxn);
12542 :
12543 : /*
12544 : * The perf_event_exit_task_context calls perf_event_task
12545 : * with child's task_ctx, which generates EXIT events for
12546 : * child contexts and sets child->perf_event_ctxp[] to NULL.
12547 : * At this point we need to send EXIT events to cpu contexts.
12548 : */
12549 1155 : perf_event_task(child, NULL, 0);
12550 1155 : }
12551 :
12552 0 : static void perf_free_event(struct perf_event *event,
12553 : struct perf_event_context *ctx)
12554 : {
12555 0 : struct perf_event *parent = event->parent;
12556 :
12557 0 : if (WARN_ON_ONCE(!parent))
12558 : return;
12559 :
12560 0 : mutex_lock(&parent->child_mutex);
12561 0 : list_del_init(&event->child_list);
12562 0 : mutex_unlock(&parent->child_mutex);
12563 :
12564 0 : put_event(parent);
12565 :
12566 0 : raw_spin_lock_irq(&ctx->lock);
12567 0 : perf_group_detach(event);
12568 0 : list_del_event(event, ctx);
12569 0 : raw_spin_unlock_irq(&ctx->lock);
12570 0 : free_event(event);
12571 : }
12572 :
12573 : /*
12574 : * Free a context as created by inheritance by perf_event_init_task() below,
12575 : * used by fork() in case of fail.
12576 : *
12577 : * Even though the task has never lived, the context and events have been
12578 : * exposed through the child_list, so we must take care tearing it all down.
12579 : */
12580 0 : void perf_event_free_task(struct task_struct *task)
12581 : {
12582 0 : struct perf_event_context *ctx;
12583 0 : struct perf_event *event, *tmp;
12584 0 : int ctxn;
12585 :
12586 0 : for_each_task_context_nr(ctxn) {
12587 0 : ctx = task->perf_event_ctxp[ctxn];
12588 0 : if (!ctx)
12589 0 : continue;
12590 :
12591 0 : mutex_lock(&ctx->mutex);
12592 0 : raw_spin_lock_irq(&ctx->lock);
12593 : /*
12594 : * Destroy the task <-> ctx relation and mark the context dead.
12595 : *
12596 : * This is important because even though the task hasn't been
12597 : * exposed yet the context has been (through child_list).
12598 : */
12599 0 : RCU_INIT_POINTER(task->perf_event_ctxp[ctxn], NULL);
12600 0 : WRITE_ONCE(ctx->task, TASK_TOMBSTONE);
12601 0 : put_task_struct(task); /* cannot be last */
12602 0 : raw_spin_unlock_irq(&ctx->lock);
12603 :
12604 0 : list_for_each_entry_safe(event, tmp, &ctx->event_list, event_entry)
12605 0 : perf_free_event(event, ctx);
12606 :
12607 0 : mutex_unlock(&ctx->mutex);
12608 :
12609 : /*
12610 : * perf_event_release_kernel() could've stolen some of our
12611 : * child events and still have them on its free_list. In that
12612 : * case we must wait for these events to have been freed (in
12613 : * particular all their references to this task must've been
12614 : * dropped).
12615 : *
12616 : * Without this copy_process() will unconditionally free this
12617 : * task (irrespective of its reference count) and
12618 : * _free_event()'s put_task_struct(event->hw.target) will be a
12619 : * use-after-free.
12620 : *
12621 : * Wait for all events to drop their context reference.
12622 : */
12623 0 : wait_var_event(&ctx->refcount, refcount_read(&ctx->refcount) == 1);
12624 0 : put_ctx(ctx); /* must be last */
12625 : }
12626 0 : }
12627 :
12628 1153 : void perf_event_delayed_put(struct task_struct *task)
12629 : {
12630 1153 : int ctxn;
12631 :
12632 3459 : for_each_task_context_nr(ctxn)
12633 2306 : WARN_ON_ONCE(task->perf_event_ctxp[ctxn]);
12634 1153 : }
12635 :
12636 0 : struct file *perf_event_get(unsigned int fd)
12637 : {
12638 0 : struct file *file = fget(fd);
12639 0 : if (!file)
12640 0 : return ERR_PTR(-EBADF);
12641 :
12642 0 : if (file->f_op != &perf_fops) {
12643 0 : fput(file);
12644 0 : return ERR_PTR(-EBADF);
12645 : }
12646 :
12647 : return file;
12648 : }
12649 :
12650 0 : const struct perf_event *perf_get_event(struct file *file)
12651 : {
12652 0 : if (file->f_op != &perf_fops)
12653 0 : return ERR_PTR(-EINVAL);
12654 :
12655 0 : return file->private_data;
12656 : }
12657 :
12658 0 : const struct perf_event_attr *perf_event_attrs(struct perf_event *event)
12659 : {
12660 0 : if (!event)
12661 0 : return ERR_PTR(-EINVAL);
12662 :
12663 0 : return &event->attr;
12664 : }
12665 :
12666 : /*
12667 : * Inherit an event from parent task to child task.
12668 : *
12669 : * Returns:
12670 : * - valid pointer on success
12671 : * - NULL for orphaned events
12672 : * - IS_ERR() on error
12673 : */
12674 : static struct perf_event *
12675 0 : inherit_event(struct perf_event *parent_event,
12676 : struct task_struct *parent,
12677 : struct perf_event_context *parent_ctx,
12678 : struct task_struct *child,
12679 : struct perf_event *group_leader,
12680 : struct perf_event_context *child_ctx)
12681 : {
12682 0 : enum perf_event_state parent_state = parent_event->state;
12683 0 : struct perf_event *child_event;
12684 0 : unsigned long flags;
12685 :
12686 : /*
12687 : * Instead of creating recursive hierarchies of events,
12688 : * we link inherited events back to the original parent,
12689 : * which has a filp for sure, which we use as the reference
12690 : * count:
12691 : */
12692 0 : if (parent_event->parent)
12693 0 : parent_event = parent_event->parent;
12694 :
12695 0 : child_event = perf_event_alloc(&parent_event->attr,
12696 : parent_event->cpu,
12697 : child,
12698 : group_leader, parent_event,
12699 : NULL, NULL, -1);
12700 0 : if (IS_ERR(child_event))
12701 : return child_event;
12702 :
12703 :
12704 0 : if ((child_event->attach_state & PERF_ATTACH_TASK_DATA) &&
12705 0 : !child_ctx->task_ctx_data) {
12706 0 : struct pmu *pmu = child_event->pmu;
12707 :
12708 0 : child_ctx->task_ctx_data = alloc_task_ctx_data(pmu);
12709 0 : if (!child_ctx->task_ctx_data) {
12710 0 : free_event(child_event);
12711 0 : return ERR_PTR(-ENOMEM);
12712 : }
12713 : }
12714 :
12715 : /*
12716 : * is_orphaned_event() and list_add_tail(&parent_event->child_list)
12717 : * must be under the same lock in order to serialize against
12718 : * perf_event_release_kernel(), such that either we must observe
12719 : * is_orphaned_event() or they will observe us on the child_list.
12720 : */
12721 0 : mutex_lock(&parent_event->child_mutex);
12722 0 : if (is_orphaned_event(parent_event) ||
12723 0 : !atomic_long_inc_not_zero(&parent_event->refcount)) {
12724 0 : mutex_unlock(&parent_event->child_mutex);
12725 : /* task_ctx_data is freed with child_ctx */
12726 0 : free_event(child_event);
12727 0 : return NULL;
12728 : }
12729 :
12730 0 : get_ctx(child_ctx);
12731 :
12732 : /*
12733 : * Make the child state follow the state of the parent event,
12734 : * not its attr.disabled bit. We hold the parent's mutex,
12735 : * so we won't race with perf_event_{en, dis}able_family.
12736 : */
12737 0 : if (parent_state >= PERF_EVENT_STATE_INACTIVE)
12738 0 : child_event->state = PERF_EVENT_STATE_INACTIVE;
12739 : else
12740 0 : child_event->state = PERF_EVENT_STATE_OFF;
12741 :
12742 0 : if (parent_event->attr.freq) {
12743 0 : u64 sample_period = parent_event->hw.sample_period;
12744 0 : struct hw_perf_event *hwc = &child_event->hw;
12745 :
12746 0 : hwc->sample_period = sample_period;
12747 0 : hwc->last_period = sample_period;
12748 :
12749 0 : local64_set(&hwc->period_left, sample_period);
12750 : }
12751 :
12752 0 : child_event->ctx = child_ctx;
12753 0 : child_event->overflow_handler = parent_event->overflow_handler;
12754 0 : child_event->overflow_handler_context
12755 0 : = parent_event->overflow_handler_context;
12756 :
12757 : /*
12758 : * Precalculate sample_data sizes
12759 : */
12760 0 : perf_event__header_size(child_event);
12761 0 : perf_event__id_header_size(child_event);
12762 :
12763 : /*
12764 : * Link it up in the child's context:
12765 : */
12766 0 : raw_spin_lock_irqsave(&child_ctx->lock, flags);
12767 0 : add_event_to_ctx(child_event, child_ctx);
12768 0 : raw_spin_unlock_irqrestore(&child_ctx->lock, flags);
12769 :
12770 : /*
12771 : * Link this into the parent event's child list
12772 : */
12773 0 : list_add_tail(&child_event->child_list, &parent_event->child_list);
12774 0 : mutex_unlock(&parent_event->child_mutex);
12775 :
12776 0 : return child_event;
12777 : }
12778 :
12779 : /*
12780 : * Inherits an event group.
12781 : *
12782 : * This will quietly suppress orphaned events; !inherit_event() is not an error.
12783 : * This matches with perf_event_release_kernel() removing all child events.
12784 : *
12785 : * Returns:
12786 : * - 0 on success
12787 : * - <0 on error
12788 : */
12789 0 : static int inherit_group(struct perf_event *parent_event,
12790 : struct task_struct *parent,
12791 : struct perf_event_context *parent_ctx,
12792 : struct task_struct *child,
12793 : struct perf_event_context *child_ctx)
12794 : {
12795 0 : struct perf_event *leader;
12796 0 : struct perf_event *sub;
12797 0 : struct perf_event *child_ctr;
12798 :
12799 0 : leader = inherit_event(parent_event, parent, parent_ctx,
12800 : child, NULL, child_ctx);
12801 0 : if (IS_ERR(leader))
12802 0 : return PTR_ERR(leader);
12803 : /*
12804 : * @leader can be NULL here because of is_orphaned_event(). In this
12805 : * case inherit_event() will create individual events, similar to what
12806 : * perf_group_detach() would do anyway.
12807 : */
12808 0 : for_each_sibling_event(sub, parent_event) {
12809 0 : child_ctr = inherit_event(sub, parent, parent_ctx,
12810 : child, leader, child_ctx);
12811 0 : if (IS_ERR(child_ctr))
12812 0 : return PTR_ERR(child_ctr);
12813 :
12814 0 : if (sub->aux_event == parent_event && child_ctr &&
12815 0 : !perf_get_aux_event(child_ctr, leader))
12816 : return -EINVAL;
12817 : }
12818 : return 0;
12819 : }
12820 :
12821 : /*
12822 : * Creates the child task context and tries to inherit the event-group.
12823 : *
12824 : * Clears @inherited_all on !attr.inherited or error. Note that we'll leave
12825 : * inherited_all set when we 'fail' to inherit an orphaned event; this is
12826 : * consistent with perf_event_release_kernel() removing all child events.
12827 : *
12828 : * Returns:
12829 : * - 0 on success
12830 : * - <0 on error
12831 : */
12832 : static int
12833 0 : inherit_task_group(struct perf_event *event, struct task_struct *parent,
12834 : struct perf_event_context *parent_ctx,
12835 : struct task_struct *child, int ctxn,
12836 : int *inherited_all)
12837 : {
12838 0 : int ret;
12839 0 : struct perf_event_context *child_ctx;
12840 :
12841 0 : if (!event->attr.inherit) {
12842 0 : *inherited_all = 0;
12843 0 : return 0;
12844 : }
12845 :
12846 0 : child_ctx = child->perf_event_ctxp[ctxn];
12847 0 : if (!child_ctx) {
12848 : /*
12849 : * This is executed from the parent task context, so
12850 : * inherit events that have been marked for cloning.
12851 : * First allocate and initialize a context for the
12852 : * child.
12853 : */
12854 0 : child_ctx = alloc_perf_context(parent_ctx->pmu, child);
12855 0 : if (!child_ctx)
12856 : return -ENOMEM;
12857 :
12858 0 : child->perf_event_ctxp[ctxn] = child_ctx;
12859 : }
12860 :
12861 0 : ret = inherit_group(event, parent, parent_ctx,
12862 : child, child_ctx);
12863 :
12864 0 : if (ret)
12865 0 : *inherited_all = 0;
12866 :
12867 : return ret;
12868 : }
12869 :
12870 : /*
12871 : * Initialize the perf_event context in task_struct
12872 : */
12873 2468 : static int perf_event_init_context(struct task_struct *child, int ctxn)
12874 : {
12875 2468 : struct perf_event_context *child_ctx, *parent_ctx;
12876 2468 : struct perf_event_context *cloned_ctx;
12877 2468 : struct perf_event *event;
12878 2468 : struct task_struct *parent = current;
12879 2468 : int inherited_all = 1;
12880 2468 : unsigned long flags;
12881 2468 : int ret = 0;
12882 :
12883 2468 : if (likely(!parent->perf_event_ctxp[ctxn]))
12884 : return 0;
12885 :
12886 : /*
12887 : * If the parent's context is a clone, pin it so it won't get
12888 : * swapped under us.
12889 : */
12890 0 : parent_ctx = perf_pin_task_context(parent, ctxn);
12891 0 : if (!parent_ctx)
12892 : return 0;
12893 :
12894 : /*
12895 : * No need to check if parent_ctx != NULL here; since we saw
12896 : * it non-NULL earlier, the only reason for it to become NULL
12897 : * is if we exit, and since we're currently in the middle of
12898 : * a fork we can't be exiting at the same time.
12899 : */
12900 :
12901 : /*
12902 : * Lock the parent list. No need to lock the child - not PID
12903 : * hashed yet and not running, so nobody can access it.
12904 : */
12905 0 : mutex_lock(&parent_ctx->mutex);
12906 :
12907 : /*
12908 : * We dont have to disable NMIs - we are only looking at
12909 : * the list, not manipulating it:
12910 : */
12911 0 : perf_event_groups_for_each(event, &parent_ctx->pinned_groups) {
12912 0 : ret = inherit_task_group(event, parent, parent_ctx,
12913 : child, ctxn, &inherited_all);
12914 0 : if (ret)
12915 0 : goto out_unlock;
12916 : }
12917 :
12918 : /*
12919 : * We can't hold ctx->lock when iterating the ->flexible_group list due
12920 : * to allocations, but we need to prevent rotation because
12921 : * rotate_ctx() will change the list from interrupt context.
12922 : */
12923 0 : raw_spin_lock_irqsave(&parent_ctx->lock, flags);
12924 0 : parent_ctx->rotate_disable = 1;
12925 0 : raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
12926 :
12927 0 : perf_event_groups_for_each(event, &parent_ctx->flexible_groups) {
12928 0 : ret = inherit_task_group(event, parent, parent_ctx,
12929 : child, ctxn, &inherited_all);
12930 0 : if (ret)
12931 0 : goto out_unlock;
12932 : }
12933 :
12934 0 : raw_spin_lock_irqsave(&parent_ctx->lock, flags);
12935 0 : parent_ctx->rotate_disable = 0;
12936 :
12937 0 : child_ctx = child->perf_event_ctxp[ctxn];
12938 :
12939 0 : if (child_ctx && inherited_all) {
12940 : /*
12941 : * Mark the child context as a clone of the parent
12942 : * context, or of whatever the parent is a clone of.
12943 : *
12944 : * Note that if the parent is a clone, the holding of
12945 : * parent_ctx->lock avoids it from being uncloned.
12946 : */
12947 0 : cloned_ctx = parent_ctx->parent_ctx;
12948 0 : if (cloned_ctx) {
12949 0 : child_ctx->parent_ctx = cloned_ctx;
12950 0 : child_ctx->parent_gen = parent_ctx->parent_gen;
12951 : } else {
12952 0 : child_ctx->parent_ctx = parent_ctx;
12953 0 : child_ctx->parent_gen = parent_ctx->generation;
12954 : }
12955 0 : get_ctx(child_ctx->parent_ctx);
12956 : }
12957 :
12958 0 : raw_spin_unlock_irqrestore(&parent_ctx->lock, flags);
12959 0 : out_unlock:
12960 0 : mutex_unlock(&parent_ctx->mutex);
12961 :
12962 0 : perf_unpin_context(parent_ctx);
12963 0 : put_ctx(parent_ctx);
12964 :
12965 0 : return ret;
12966 : }
12967 :
12968 : /*
12969 : * Initialize the perf_event context in task_struct
12970 : */
12971 1234 : int perf_event_init_task(struct task_struct *child)
12972 : {
12973 1234 : int ctxn, ret;
12974 :
12975 1234 : memset(child->perf_event_ctxp, 0, sizeof(child->perf_event_ctxp));
12976 1234 : mutex_init(&child->perf_event_mutex);
12977 1234 : INIT_LIST_HEAD(&child->perf_event_list);
12978 :
12979 3702 : for_each_task_context_nr(ctxn) {
12980 2468 : ret = perf_event_init_context(child, ctxn);
12981 2468 : if (ret) {
12982 0 : perf_event_free_task(child);
12983 0 : return ret;
12984 : }
12985 : }
12986 :
12987 : return 0;
12988 : }
12989 :
12990 1 : static void __init perf_event_init_all_cpus(void)
12991 : {
12992 1 : struct swevent_htable *swhash;
12993 1 : int cpu;
12994 :
12995 1 : zalloc_cpumask_var(&perf_online_mask, GFP_KERNEL);
12996 :
12997 6 : for_each_possible_cpu(cpu) {
12998 4 : swhash = &per_cpu(swevent_htable, cpu);
12999 4 : mutex_init(&swhash->hlist_mutex);
13000 4 : INIT_LIST_HEAD(&per_cpu(active_ctx_list, cpu));
13001 :
13002 4 : INIT_LIST_HEAD(&per_cpu(pmu_sb_events.list, cpu));
13003 4 : raw_spin_lock_init(&per_cpu(pmu_sb_events.lock, cpu));
13004 :
13005 : #ifdef CONFIG_CGROUP_PERF
13006 : INIT_LIST_HEAD(&per_cpu(cgrp_cpuctx_list, cpu));
13007 : #endif
13008 5 : INIT_LIST_HEAD(&per_cpu(sched_cb_list, cpu));
13009 : }
13010 1 : }
13011 :
13012 7 : static void perf_swevent_init_cpu(unsigned int cpu)
13013 : {
13014 7 : struct swevent_htable *swhash = &per_cpu(swevent_htable, cpu);
13015 :
13016 7 : mutex_lock(&swhash->hlist_mutex);
13017 7 : if (swhash->hlist_refcount > 0 && !swevent_hlist_deref(swhash)) {
13018 0 : struct swevent_hlist *hlist;
13019 :
13020 0 : hlist = kzalloc_node(sizeof(*hlist), GFP_KERNEL, cpu_to_node(cpu));
13021 0 : WARN_ON(!hlist);
13022 0 : rcu_assign_pointer(swhash->swevent_hlist, hlist);
13023 : }
13024 7 : mutex_unlock(&swhash->hlist_mutex);
13025 7 : }
13026 :
13027 : #if defined CONFIG_HOTPLUG_CPU || defined CONFIG_KEXEC_CORE
13028 0 : static void __perf_event_exit_context(void *__info)
13029 : {
13030 0 : struct perf_event_context *ctx = __info;
13031 0 : struct perf_cpu_context *cpuctx = __get_cpu_context(ctx);
13032 0 : struct perf_event *event;
13033 :
13034 0 : raw_spin_lock(&ctx->lock);
13035 0 : ctx_sched_out(ctx, cpuctx, EVENT_TIME);
13036 0 : list_for_each_entry(event, &ctx->event_list, event_entry)
13037 0 : __perf_remove_from_context(event, cpuctx, ctx, (void *)DETACH_GROUP);
13038 0 : raw_spin_unlock(&ctx->lock);
13039 0 : }
13040 :
13041 0 : static void perf_event_exit_cpu_context(int cpu)
13042 : {
13043 0 : struct perf_cpu_context *cpuctx;
13044 0 : struct perf_event_context *ctx;
13045 0 : struct pmu *pmu;
13046 :
13047 0 : mutex_lock(&pmus_lock);
13048 0 : list_for_each_entry(pmu, &pmus, entry) {
13049 0 : cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
13050 0 : ctx = &cpuctx->ctx;
13051 :
13052 0 : mutex_lock(&ctx->mutex);
13053 0 : smp_call_function_single(cpu, __perf_event_exit_context, ctx, 1);
13054 0 : cpuctx->online = 0;
13055 0 : mutex_unlock(&ctx->mutex);
13056 : }
13057 0 : cpumask_clear_cpu(cpu, perf_online_mask);
13058 0 : mutex_unlock(&pmus_lock);
13059 0 : }
13060 : #else
13061 :
13062 : static void perf_event_exit_cpu_context(int cpu) { }
13063 :
13064 : #endif
13065 :
13066 7 : int perf_event_init_cpu(unsigned int cpu)
13067 : {
13068 7 : struct perf_cpu_context *cpuctx;
13069 7 : struct perf_event_context *ctx;
13070 7 : struct pmu *pmu;
13071 :
13072 7 : perf_swevent_init_cpu(cpu);
13073 :
13074 7 : mutex_lock(&pmus_lock);
13075 7 : cpumask_set_cpu(cpu, perf_online_mask);
13076 47 : list_for_each_entry(pmu, &pmus, entry) {
13077 40 : cpuctx = per_cpu_ptr(pmu->pmu_cpu_context, cpu);
13078 40 : ctx = &cpuctx->ctx;
13079 :
13080 40 : mutex_lock(&ctx->mutex);
13081 40 : cpuctx->online = 1;
13082 40 : mutex_unlock(&ctx->mutex);
13083 : }
13084 7 : mutex_unlock(&pmus_lock);
13085 :
13086 7 : return 0;
13087 : }
13088 :
13089 0 : int perf_event_exit_cpu(unsigned int cpu)
13090 : {
13091 0 : perf_event_exit_cpu_context(cpu);
13092 0 : return 0;
13093 : }
13094 :
13095 : static int
13096 0 : perf_reboot(struct notifier_block *notifier, unsigned long val, void *v)
13097 : {
13098 0 : int cpu;
13099 :
13100 0 : for_each_online_cpu(cpu)
13101 0 : perf_event_exit_cpu(cpu);
13102 :
13103 0 : return NOTIFY_OK;
13104 : }
13105 :
13106 : /*
13107 : * Run the perf reboot notifier at the very last possible moment so that
13108 : * the generic watchdog code runs as long as possible.
13109 : */
13110 : static struct notifier_block perf_reboot_notifier = {
13111 : .notifier_call = perf_reboot,
13112 : .priority = INT_MIN,
13113 : };
13114 :
13115 1 : void __init perf_event_init(void)
13116 : {
13117 1 : int ret;
13118 :
13119 1 : idr_init(&pmu_idr);
13120 :
13121 1 : perf_event_init_all_cpus();
13122 1 : init_srcu_struct(&pmus_srcu);
13123 1 : perf_pmu_register(&perf_swevent, "software", PERF_TYPE_SOFTWARE);
13124 1 : perf_pmu_register(&perf_cpu_clock, NULL, -1);
13125 1 : perf_pmu_register(&perf_task_clock, NULL, -1);
13126 1 : perf_tp_register();
13127 1 : perf_event_init_cpu(smp_processor_id());
13128 1 : register_reboot_notifier(&perf_reboot_notifier);
13129 :
13130 1 : ret = init_hw_breakpoint();
13131 1 : WARN(ret, "hw_breakpoint initialization failed with: %d", ret);
13132 :
13133 : /*
13134 : * Build time assertion that we keep the data_head at the intended
13135 : * location. IOW, validation we got the __reserved[] size right.
13136 : */
13137 1 : BUILD_BUG_ON((offsetof(struct perf_event_mmap_page, data_head))
13138 : != 1024);
13139 1 : }
13140 :
13141 0 : ssize_t perf_event_sysfs_show(struct device *dev, struct device_attribute *attr,
13142 : char *page)
13143 : {
13144 0 : struct perf_pmu_events_attr *pmu_attr =
13145 0 : container_of(attr, struct perf_pmu_events_attr, attr);
13146 :
13147 0 : if (pmu_attr->event_str)
13148 0 : return sprintf(page, "%s\n", pmu_attr->event_str);
13149 :
13150 : return 0;
13151 : }
13152 : EXPORT_SYMBOL_GPL(perf_event_sysfs_show);
13153 :
13154 1 : static int __init perf_event_sysfs_init(void)
13155 : {
13156 1 : struct pmu *pmu;
13157 1 : int ret;
13158 :
13159 1 : mutex_lock(&pmus_lock);
13160 :
13161 1 : ret = bus_register(&pmu_bus);
13162 1 : if (ret)
13163 0 : goto unlock;
13164 :
13165 8 : list_for_each_entry(pmu, &pmus, entry) {
13166 7 : if (!pmu->name || pmu->type < 0)
13167 2 : continue;
13168 :
13169 5 : ret = pmu_dev_alloc(pmu);
13170 5 : WARN(ret, "Failed to register pmu: %s, reason %d\n", pmu->name, ret);
13171 : }
13172 1 : pmu_bus_running = 1;
13173 1 : ret = 0;
13174 :
13175 1 : unlock:
13176 1 : mutex_unlock(&pmus_lock);
13177 :
13178 1 : return ret;
13179 : }
13180 : device_initcall(perf_event_sysfs_init);
13181 :
13182 : #ifdef CONFIG_CGROUP_PERF
13183 : static struct cgroup_subsys_state *
13184 : perf_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
13185 : {
13186 : struct perf_cgroup *jc;
13187 :
13188 : jc = kzalloc(sizeof(*jc), GFP_KERNEL);
13189 : if (!jc)
13190 : return ERR_PTR(-ENOMEM);
13191 :
13192 : jc->info = alloc_percpu(struct perf_cgroup_info);
13193 : if (!jc->info) {
13194 : kfree(jc);
13195 : return ERR_PTR(-ENOMEM);
13196 : }
13197 :
13198 : return &jc->css;
13199 : }
13200 :
13201 : static void perf_cgroup_css_free(struct cgroup_subsys_state *css)
13202 : {
13203 : struct perf_cgroup *jc = container_of(css, struct perf_cgroup, css);
13204 :
13205 : free_percpu(jc->info);
13206 : kfree(jc);
13207 : }
13208 :
13209 : static int perf_cgroup_css_online(struct cgroup_subsys_state *css)
13210 : {
13211 : perf_event_cgroup(css->cgroup);
13212 : return 0;
13213 : }
13214 :
13215 : static int __perf_cgroup_move(void *info)
13216 : {
13217 : struct task_struct *task = info;
13218 : rcu_read_lock();
13219 : perf_cgroup_switch(task, PERF_CGROUP_SWOUT | PERF_CGROUP_SWIN);
13220 : rcu_read_unlock();
13221 : return 0;
13222 : }
13223 :
13224 : static void perf_cgroup_attach(struct cgroup_taskset *tset)
13225 : {
13226 : struct task_struct *task;
13227 : struct cgroup_subsys_state *css;
13228 :
13229 : cgroup_taskset_for_each(task, css, tset)
13230 : task_function_call(task, __perf_cgroup_move, task);
13231 : }
13232 :
13233 : struct cgroup_subsys perf_event_cgrp_subsys = {
13234 : .css_alloc = perf_cgroup_css_alloc,
13235 : .css_free = perf_cgroup_css_free,
13236 : .css_online = perf_cgroup_css_online,
13237 : .attach = perf_cgroup_attach,
13238 : /*
13239 : * Implicitly enable on dfl hierarchy so that perf events can
13240 : * always be filtered by cgroup2 path as long as perf_event
13241 : * controller is not mounted on a legacy hierarchy.
13242 : */
13243 : .implicit_on_dfl = true,
13244 : .threaded = true,
13245 : };
13246 : #endif /* CONFIG_CGROUP_PERF */
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