Line data Source code
1 : // SPDX-License-Identifier: GPL-2.0
2 : /*
3 : * Kernel timekeeping code and accessor functions. Based on code from
4 : * timer.c, moved in commit 8524070b7982.
5 : */
6 : #include <linux/timekeeper_internal.h>
7 : #include <linux/module.h>
8 : #include <linux/interrupt.h>
9 : #include <linux/percpu.h>
10 : #include <linux/init.h>
11 : #include <linux/mm.h>
12 : #include <linux/nmi.h>
13 : #include <linux/sched.h>
14 : #include <linux/sched/loadavg.h>
15 : #include <linux/sched/clock.h>
16 : #include <linux/syscore_ops.h>
17 : #include <linux/clocksource.h>
18 : #include <linux/jiffies.h>
19 : #include <linux/time.h>
20 : #include <linux/tick.h>
21 : #include <linux/stop_machine.h>
22 : #include <linux/pvclock_gtod.h>
23 : #include <linux/compiler.h>
24 : #include <linux/audit.h>
25 :
26 : #include "tick-internal.h"
27 : #include "ntp_internal.h"
28 : #include "timekeeping_internal.h"
29 :
30 : #define TK_CLEAR_NTP (1 << 0)
31 : #define TK_MIRROR (1 << 1)
32 : #define TK_CLOCK_WAS_SET (1 << 2)
33 :
34 : enum timekeeping_adv_mode {
35 : /* Update timekeeper when a tick has passed */
36 : TK_ADV_TICK,
37 :
38 : /* Update timekeeper on a direct frequency change */
39 : TK_ADV_FREQ
40 : };
41 :
42 : DEFINE_RAW_SPINLOCK(timekeeper_lock);
43 :
44 : /*
45 : * The most important data for readout fits into a single 64 byte
46 : * cache line.
47 : */
48 : static struct {
49 : seqcount_raw_spinlock_t seq;
50 : struct timekeeper timekeeper;
51 : } tk_core ____cacheline_aligned = {
52 : .seq = SEQCNT_RAW_SPINLOCK_ZERO(tk_core.seq, &timekeeper_lock),
53 : };
54 :
55 : static struct timekeeper shadow_timekeeper;
56 :
57 : /* flag for if timekeeping is suspended */
58 : int __read_mostly timekeeping_suspended;
59 :
60 : /**
61 : * struct tk_fast - NMI safe timekeeper
62 : * @seq: Sequence counter for protecting updates. The lowest bit
63 : * is the index for the tk_read_base array
64 : * @base: tk_read_base array. Access is indexed by the lowest bit of
65 : * @seq.
66 : *
67 : * See @update_fast_timekeeper() below.
68 : */
69 : struct tk_fast {
70 : seqcount_latch_t seq;
71 : struct tk_read_base base[2];
72 : };
73 :
74 : /* Suspend-time cycles value for halted fast timekeeper. */
75 : static u64 cycles_at_suspend;
76 :
77 0 : static u64 dummy_clock_read(struct clocksource *cs)
78 : {
79 0 : if (timekeeping_suspended)
80 0 : return cycles_at_suspend;
81 0 : return local_clock();
82 : }
83 :
84 : static struct clocksource dummy_clock = {
85 : .read = dummy_clock_read,
86 : };
87 :
88 : /*
89 : * Boot time initialization which allows local_clock() to be utilized
90 : * during early boot when clocksources are not available. local_clock()
91 : * returns nanoseconds already so no conversion is required, hence mult=1
92 : * and shift=0. When the first proper clocksource is installed then
93 : * the fast time keepers are updated with the correct values.
94 : */
95 : #define FAST_TK_INIT \
96 : { \
97 : .clock = &dummy_clock, \
98 : .mask = CLOCKSOURCE_MASK(64), \
99 : .mult = 1, \
100 : .shift = 0, \
101 : }
102 :
103 : static struct tk_fast tk_fast_mono ____cacheline_aligned = {
104 : .seq = SEQCNT_LATCH_ZERO(tk_fast_mono.seq),
105 : .base[0] = FAST_TK_INIT,
106 : .base[1] = FAST_TK_INIT,
107 : };
108 :
109 : static struct tk_fast tk_fast_raw ____cacheline_aligned = {
110 : .seq = SEQCNT_LATCH_ZERO(tk_fast_raw.seq),
111 : .base[0] = FAST_TK_INIT,
112 : .base[1] = FAST_TK_INIT,
113 : };
114 :
115 1 : static inline void tk_normalize_xtime(struct timekeeper *tk)
116 : {
117 1 : while (tk->tkr_mono.xtime_nsec >= ((u64)NSEC_PER_SEC << tk->tkr_mono.shift)) {
118 0 : tk->tkr_mono.xtime_nsec -= (u64)NSEC_PER_SEC << tk->tkr_mono.shift;
119 0 : tk->xtime_sec++;
120 : }
121 1 : while (tk->tkr_raw.xtime_nsec >= ((u64)NSEC_PER_SEC << tk->tkr_raw.shift)) {
122 0 : tk->tkr_raw.xtime_nsec -= (u64)NSEC_PER_SEC << tk->tkr_raw.shift;
123 0 : tk->raw_sec++;
124 : }
125 1 : }
126 :
127 79951 : static inline struct timespec64 tk_xtime(const struct timekeeper *tk)
128 : {
129 79951 : struct timespec64 ts;
130 :
131 79951 : ts.tv_sec = tk->xtime_sec;
132 79951 : ts.tv_nsec = (long)(tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift);
133 79951 : return ts;
134 : }
135 :
136 1 : static void tk_set_xtime(struct timekeeper *tk, const struct timespec64 *ts)
137 : {
138 1 : tk->xtime_sec = ts->tv_sec;
139 1 : tk->tkr_mono.xtime_nsec = (u64)ts->tv_nsec << tk->tkr_mono.shift;
140 0 : }
141 :
142 0 : static void tk_xtime_add(struct timekeeper *tk, const struct timespec64 *ts)
143 : {
144 0 : tk->xtime_sec += ts->tv_sec;
145 0 : tk->tkr_mono.xtime_nsec += (u64)ts->tv_nsec << tk->tkr_mono.shift;
146 0 : tk_normalize_xtime(tk);
147 0 : }
148 :
149 1 : static void tk_set_wall_to_mono(struct timekeeper *tk, struct timespec64 wtm)
150 : {
151 1 : struct timespec64 tmp;
152 :
153 : /*
154 : * Verify consistency of: offset_real = -wall_to_monotonic
155 : * before modifying anything
156 : */
157 1 : set_normalized_timespec64(&tmp, -tk->wall_to_monotonic.tv_sec,
158 1 : -tk->wall_to_monotonic.tv_nsec);
159 2 : WARN_ON_ONCE(tk->offs_real != timespec64_to_ktime(tmp));
160 1 : tk->wall_to_monotonic = wtm;
161 1 : set_normalized_timespec64(&tmp, -wtm.tv_sec, -wtm.tv_nsec);
162 1 : tk->offs_real = timespec64_to_ktime(tmp);
163 1 : tk->offs_tai = ktime_add(tk->offs_real, ktime_set(tk->tai_offset, 0));
164 1 : }
165 :
166 0 : static inline void tk_update_sleep_time(struct timekeeper *tk, ktime_t delta)
167 : {
168 0 : tk->offs_boot = ktime_add(tk->offs_boot, delta);
169 : /*
170 : * Timespec representation for VDSO update to avoid 64bit division
171 : * on every update.
172 : */
173 0 : tk->monotonic_to_boot = ktime_to_timespec64(tk->offs_boot);
174 : }
175 :
176 : /*
177 : * tk_clock_read - atomic clocksource read() helper
178 : *
179 : * This helper is necessary to use in the read paths because, while the
180 : * seqcount ensures we don't return a bad value while structures are updated,
181 : * it doesn't protect from potential crashes. There is the possibility that
182 : * the tkr's clocksource may change between the read reference, and the
183 : * clock reference passed to the read function. This can cause crashes if
184 : * the wrong clocksource is passed to the wrong read function.
185 : * This isn't necessary to use when holding the timekeeper_lock or doing
186 : * a read of the fast-timekeeper tkrs (which is protected by its own locking
187 : * and update logic).
188 : */
189 148444 : static inline u64 tk_clock_read(const struct tk_read_base *tkr)
190 : {
191 148444 : struct clocksource *clock = READ_ONCE(tkr->clock);
192 :
193 148444 : return clock->read(clock);
194 : }
195 :
196 : #ifdef CONFIG_DEBUG_TIMEKEEPING
197 : #define WARNING_FREQ (HZ*300) /* 5 minute rate-limiting */
198 :
199 : static void timekeeping_check_update(struct timekeeper *tk, u64 offset)
200 : {
201 :
202 : u64 max_cycles = tk->tkr_mono.clock->max_cycles;
203 : const char *name = tk->tkr_mono.clock->name;
204 :
205 : if (offset > max_cycles) {
206 : printk_deferred("WARNING: timekeeping: Cycle offset (%lld) is larger than allowed by the '%s' clock's max_cycles value (%lld): time overflow danger\n",
207 : offset, name, max_cycles);
208 : printk_deferred(" timekeeping: Your kernel is sick, but tries to cope by capping time updates\n");
209 : } else {
210 : if (offset > (max_cycles >> 1)) {
211 : printk_deferred("INFO: timekeeping: Cycle offset (%lld) is larger than the '%s' clock's 50%% safety margin (%lld)\n",
212 : offset, name, max_cycles >> 1);
213 : printk_deferred(" timekeeping: Your kernel is still fine, but is feeling a bit nervous\n");
214 : }
215 : }
216 :
217 : if (tk->underflow_seen) {
218 : if (jiffies - tk->last_warning > WARNING_FREQ) {
219 : printk_deferred("WARNING: Underflow in clocksource '%s' observed, time update ignored.\n", name);
220 : printk_deferred(" Please report this, consider using a different clocksource, if possible.\n");
221 : printk_deferred(" Your kernel is probably still fine.\n");
222 : tk->last_warning = jiffies;
223 : }
224 : tk->underflow_seen = 0;
225 : }
226 :
227 : if (tk->overflow_seen) {
228 : if (jiffies - tk->last_warning > WARNING_FREQ) {
229 : printk_deferred("WARNING: Overflow in clocksource '%s' observed, time update capped.\n", name);
230 : printk_deferred(" Please report this, consider using a different clocksource, if possible.\n");
231 : printk_deferred(" Your kernel is probably still fine.\n");
232 : tk->last_warning = jiffies;
233 : }
234 : tk->overflow_seen = 0;
235 : }
236 : }
237 :
238 : static inline u64 timekeeping_get_delta(const struct tk_read_base *tkr)
239 : {
240 : struct timekeeper *tk = &tk_core.timekeeper;
241 : u64 now, last, mask, max, delta;
242 : unsigned int seq;
243 :
244 : /*
245 : * Since we're called holding a seqcount, the data may shift
246 : * under us while we're doing the calculation. This can cause
247 : * false positives, since we'd note a problem but throw the
248 : * results away. So nest another seqcount here to atomically
249 : * grab the points we are checking with.
250 : */
251 : do {
252 : seq = read_seqcount_begin(&tk_core.seq);
253 : now = tk_clock_read(tkr);
254 : last = tkr->cycle_last;
255 : mask = tkr->mask;
256 : max = tkr->clock->max_cycles;
257 : } while (read_seqcount_retry(&tk_core.seq, seq));
258 :
259 : delta = clocksource_delta(now, last, mask);
260 :
261 : /*
262 : * Try to catch underflows by checking if we are seeing small
263 : * mask-relative negative values.
264 : */
265 : if (unlikely((~delta & mask) < (mask >> 3))) {
266 : tk->underflow_seen = 1;
267 : delta = 0;
268 : }
269 :
270 : /* Cap delta value to the max_cycles values to avoid mult overflows */
271 : if (unlikely(delta > max)) {
272 : tk->overflow_seen = 1;
273 : delta = tkr->clock->max_cycles;
274 : }
275 :
276 : return delta;
277 : }
278 : #else
279 7943 : static inline void timekeeping_check_update(struct timekeeper *tk, u64 offset)
280 : {
281 7943 : }
282 140374 : static inline u64 timekeeping_get_delta(const struct tk_read_base *tkr)
283 : {
284 140374 : u64 cycle_now, delta;
285 :
286 : /* read clocksource */
287 140374 : cycle_now = tk_clock_read(tkr);
288 :
289 : /* calculate the delta since the last update_wall_time */
290 141365 : delta = clocksource_delta(cycle_now, tkr->cycle_last, tkr->mask);
291 :
292 141365 : return delta;
293 : }
294 : #endif
295 :
296 : /**
297 : * tk_setup_internals - Set up internals to use clocksource clock.
298 : *
299 : * @tk: The target timekeeper to setup.
300 : * @clock: Pointer to clocksource.
301 : *
302 : * Calculates a fixed cycle/nsec interval for a given clocksource/adjustment
303 : * pair and interval request.
304 : *
305 : * Unless you're the timekeeping code, you should not be using this!
306 : */
307 2 : static void tk_setup_internals(struct timekeeper *tk, struct clocksource *clock)
308 : {
309 2 : u64 interval;
310 2 : u64 tmp, ntpinterval;
311 2 : struct clocksource *old_clock;
312 :
313 2 : ++tk->cs_was_changed_seq;
314 2 : old_clock = tk->tkr_mono.clock;
315 2 : tk->tkr_mono.clock = clock;
316 2 : tk->tkr_mono.mask = clock->mask;
317 2 : tk->tkr_mono.cycle_last = tk_clock_read(&tk->tkr_mono);
318 :
319 2 : tk->tkr_raw.clock = clock;
320 2 : tk->tkr_raw.mask = clock->mask;
321 2 : tk->tkr_raw.cycle_last = tk->tkr_mono.cycle_last;
322 :
323 : /* Do the ns -> cycle conversion first, using original mult */
324 2 : tmp = NTP_INTERVAL_LENGTH;
325 2 : tmp <<= clock->shift;
326 2 : ntpinterval = tmp;
327 2 : tmp += clock->mult/2;
328 2 : do_div(tmp, clock->mult);
329 2 : if (tmp == 0)
330 0 : tmp = 1;
331 :
332 2 : interval = (u64) tmp;
333 2 : tk->cycle_interval = interval;
334 :
335 : /* Go back from cycles -> shifted ns */
336 2 : tk->xtime_interval = interval * clock->mult;
337 2 : tk->xtime_remainder = ntpinterval - tk->xtime_interval;
338 2 : tk->raw_interval = interval * clock->mult;
339 :
340 : /* if changing clocks, convert xtime_nsec shift units */
341 2 : if (old_clock) {
342 1 : int shift_change = clock->shift - old_clock->shift;
343 1 : if (shift_change < 0) {
344 0 : tk->tkr_mono.xtime_nsec >>= -shift_change;
345 0 : tk->tkr_raw.xtime_nsec >>= -shift_change;
346 : } else {
347 1 : tk->tkr_mono.xtime_nsec <<= shift_change;
348 1 : tk->tkr_raw.xtime_nsec <<= shift_change;
349 : }
350 : }
351 :
352 2 : tk->tkr_mono.shift = clock->shift;
353 2 : tk->tkr_raw.shift = clock->shift;
354 :
355 2 : tk->ntp_error = 0;
356 2 : tk->ntp_error_shift = NTP_SCALE_SHIFT - clock->shift;
357 2 : tk->ntp_tick = ntpinterval << tk->ntp_error_shift;
358 :
359 : /*
360 : * The timekeeper keeps its own mult values for the currently
361 : * active clocksource. These value will be adjusted via NTP
362 : * to counteract clock drifting.
363 : */
364 2 : tk->tkr_mono.mult = clock->mult;
365 2 : tk->tkr_raw.mult = clock->mult;
366 2 : tk->ntp_err_mult = 0;
367 2 : tk->skip_second_overflow = 0;
368 2 : }
369 :
370 : /* Timekeeper helper functions. */
371 :
372 141504 : static inline u64 timekeeping_delta_to_ns(const struct tk_read_base *tkr, u64 delta)
373 : {
374 141504 : u64 nsec;
375 :
376 141504 : nsec = delta * tkr->mult + tkr->xtime_nsec;
377 141504 : nsec >>= tkr->shift;
378 :
379 141504 : return nsec;
380 : }
381 :
382 140362 : static inline u64 timekeeping_get_ns(const struct tk_read_base *tkr)
383 : {
384 140362 : u64 delta;
385 :
386 140362 : delta = timekeeping_get_delta(tkr);
387 141382 : return timekeeping_delta_to_ns(tkr, delta);
388 : }
389 :
390 0 : static inline u64 timekeeping_cycles_to_ns(const struct tk_read_base *tkr, u64 cycles)
391 : {
392 0 : u64 delta;
393 :
394 : /* calculate the delta since the last update_wall_time */
395 0 : delta = clocksource_delta(cycles, tkr->cycle_last, tkr->mask);
396 0 : return timekeeping_delta_to_ns(tkr, delta);
397 : }
398 :
399 : /**
400 : * update_fast_timekeeper - Update the fast and NMI safe monotonic timekeeper.
401 : * @tkr: Timekeeping readout base from which we take the update
402 : * @tkf: Pointer to NMI safe timekeeper
403 : *
404 : * We want to use this from any context including NMI and tracing /
405 : * instrumenting the timekeeping code itself.
406 : *
407 : * Employ the latch technique; see @raw_write_seqcount_latch.
408 : *
409 : * So if a NMI hits the update of base[0] then it will use base[1]
410 : * which is still consistent. In the worst case this can result is a
411 : * slightly wrong timestamp (a few nanoseconds). See
412 : * @ktime_get_mono_fast_ns.
413 : */
414 15894 : static void update_fast_timekeeper(const struct tk_read_base *tkr,
415 : struct tk_fast *tkf)
416 : {
417 15894 : struct tk_read_base *base = tkf->base;
418 :
419 : /* Force readers off to base[1] */
420 15894 : raw_write_seqcount_latch(&tkf->seq);
421 :
422 : /* Update base[0] */
423 15894 : memcpy(base, tkr, sizeof(*base));
424 :
425 : /* Force readers back to base[0] */
426 15894 : raw_write_seqcount_latch(&tkf->seq);
427 :
428 : /* Update base[1] */
429 15894 : memcpy(base + 1, base, sizeof(*base));
430 15894 : }
431 :
432 122 : static __always_inline u64 __ktime_get_fast_ns(struct tk_fast *tkf)
433 : {
434 122 : struct tk_read_base *tkr;
435 122 : unsigned int seq;
436 122 : u64 now;
437 :
438 122 : do {
439 122 : seq = raw_read_seqcount_latch(&tkf->seq);
440 122 : tkr = tkf->base + (seq & 0x01);
441 122 : now = ktime_to_ns(tkr->base);
442 :
443 122 : now += timekeeping_delta_to_ns(tkr,
444 : clocksource_delta(
445 : tk_clock_read(tkr),
446 : tkr->cycle_last,
447 : tkr->mask));
448 122 : } while (read_seqcount_latch_retry(&tkf->seq, seq));
449 :
450 122 : return now;
451 : }
452 :
453 : /**
454 : * ktime_get_mono_fast_ns - Fast NMI safe access to clock monotonic
455 : *
456 : * This timestamp is not guaranteed to be monotonic across an update.
457 : * The timestamp is calculated by:
458 : *
459 : * now = base_mono + clock_delta * slope
460 : *
461 : * So if the update lowers the slope, readers who are forced to the
462 : * not yet updated second array are still using the old steeper slope.
463 : *
464 : * tmono
465 : * ^
466 : * | o n
467 : * | o n
468 : * | u
469 : * | o
470 : * |o
471 : * |12345678---> reader order
472 : *
473 : * o = old slope
474 : * u = update
475 : * n = new slope
476 : *
477 : * So reader 6 will observe time going backwards versus reader 5.
478 : *
479 : * While other CPUs are likely to be able to observe that, the only way
480 : * for a CPU local observation is when an NMI hits in the middle of
481 : * the update. Timestamps taken from that NMI context might be ahead
482 : * of the following timestamps. Callers need to be aware of that and
483 : * deal with it.
484 : */
485 122 : u64 ktime_get_mono_fast_ns(void)
486 : {
487 122 : return __ktime_get_fast_ns(&tk_fast_mono);
488 : }
489 : EXPORT_SYMBOL_GPL(ktime_get_mono_fast_ns);
490 :
491 : /**
492 : * ktime_get_raw_fast_ns - Fast NMI safe access to clock monotonic raw
493 : *
494 : * Contrary to ktime_get_mono_fast_ns() this is always correct because the
495 : * conversion factor is not affected by NTP/PTP correction.
496 : */
497 0 : u64 ktime_get_raw_fast_ns(void)
498 : {
499 0 : return __ktime_get_fast_ns(&tk_fast_raw);
500 : }
501 : EXPORT_SYMBOL_GPL(ktime_get_raw_fast_ns);
502 :
503 : /**
504 : * ktime_get_boot_fast_ns - NMI safe and fast access to boot clock.
505 : *
506 : * To keep it NMI safe since we're accessing from tracing, we're not using a
507 : * separate timekeeper with updates to monotonic clock and boot offset
508 : * protected with seqcounts. This has the following minor side effects:
509 : *
510 : * (1) Its possible that a timestamp be taken after the boot offset is updated
511 : * but before the timekeeper is updated. If this happens, the new boot offset
512 : * is added to the old timekeeping making the clock appear to update slightly
513 : * earlier:
514 : * CPU 0 CPU 1
515 : * timekeeping_inject_sleeptime64()
516 : * __timekeeping_inject_sleeptime(tk, delta);
517 : * timestamp();
518 : * timekeeping_update(tk, TK_CLEAR_NTP...);
519 : *
520 : * (2) On 32-bit systems, the 64-bit boot offset (tk->offs_boot) may be
521 : * partially updated. Since the tk->offs_boot update is a rare event, this
522 : * should be a rare occurrence which postprocessing should be able to handle.
523 : *
524 : * The caveats vs. timestamp ordering as documented for ktime_get_fast_ns()
525 : * apply as well.
526 : */
527 0 : u64 notrace ktime_get_boot_fast_ns(void)
528 : {
529 0 : struct timekeeper *tk = &tk_core.timekeeper;
530 :
531 0 : return (ktime_get_mono_fast_ns() + ktime_to_ns(tk->offs_boot));
532 : }
533 : EXPORT_SYMBOL_GPL(ktime_get_boot_fast_ns);
534 :
535 0 : static __always_inline u64 __ktime_get_real_fast(struct tk_fast *tkf, u64 *mono)
536 : {
537 0 : struct tk_read_base *tkr;
538 0 : u64 basem, baser, delta;
539 0 : unsigned int seq;
540 :
541 0 : do {
542 0 : seq = raw_read_seqcount_latch(&tkf->seq);
543 0 : tkr = tkf->base + (seq & 0x01);
544 0 : basem = ktime_to_ns(tkr->base);
545 0 : baser = ktime_to_ns(tkr->base_real);
546 :
547 0 : delta = timekeeping_delta_to_ns(tkr,
548 : clocksource_delta(tk_clock_read(tkr),
549 : tkr->cycle_last, tkr->mask));
550 0 : } while (read_seqcount_latch_retry(&tkf->seq, seq));
551 :
552 0 : if (mono)
553 0 : *mono = basem + delta;
554 0 : return baser + delta;
555 : }
556 :
557 : /**
558 : * ktime_get_real_fast_ns: - NMI safe and fast access to clock realtime.
559 : *
560 : * See ktime_get_fast_ns() for documentation of the time stamp ordering.
561 : */
562 0 : u64 ktime_get_real_fast_ns(void)
563 : {
564 0 : return __ktime_get_real_fast(&tk_fast_mono, NULL);
565 : }
566 : EXPORT_SYMBOL_GPL(ktime_get_real_fast_ns);
567 :
568 : /**
569 : * ktime_get_fast_timestamps: - NMI safe timestamps
570 : * @snapshot: Pointer to timestamp storage
571 : *
572 : * Stores clock monotonic, boottime and realtime timestamps.
573 : *
574 : * Boot time is a racy access on 32bit systems if the sleep time injection
575 : * happens late during resume and not in timekeeping_resume(). That could
576 : * be avoided by expanding struct tk_read_base with boot offset for 32bit
577 : * and adding more overhead to the update. As this is a hard to observe
578 : * once per resume event which can be filtered with reasonable effort using
579 : * the accurate mono/real timestamps, it's probably not worth the trouble.
580 : *
581 : * Aside of that it might be possible on 32 and 64 bit to observe the
582 : * following when the sleep time injection happens late:
583 : *
584 : * CPU 0 CPU 1
585 : * timekeeping_resume()
586 : * ktime_get_fast_timestamps()
587 : * mono, real = __ktime_get_real_fast()
588 : * inject_sleep_time()
589 : * update boot offset
590 : * boot = mono + bootoffset;
591 : *
592 : * That means that boot time already has the sleep time adjustment, but
593 : * real time does not. On the next readout both are in sync again.
594 : *
595 : * Preventing this for 64bit is not really feasible without destroying the
596 : * careful cache layout of the timekeeper because the sequence count and
597 : * struct tk_read_base would then need two cache lines instead of one.
598 : *
599 : * Access to the time keeper clock source is disabled accross the innermost
600 : * steps of suspend/resume. The accessors still work, but the timestamps
601 : * are frozen until time keeping is resumed which happens very early.
602 : *
603 : * For regular suspend/resume there is no observable difference vs. sched
604 : * clock, but it might affect some of the nasty low level debug printks.
605 : *
606 : * OTOH, access to sched clock is not guaranteed accross suspend/resume on
607 : * all systems either so it depends on the hardware in use.
608 : *
609 : * If that turns out to be a real problem then this could be mitigated by
610 : * using sched clock in a similar way as during early boot. But it's not as
611 : * trivial as on early boot because it needs some careful protection
612 : * against the clock monotonic timestamp jumping backwards on resume.
613 : */
614 0 : void ktime_get_fast_timestamps(struct ktime_timestamps *snapshot)
615 : {
616 0 : struct timekeeper *tk = &tk_core.timekeeper;
617 :
618 0 : snapshot->real = __ktime_get_real_fast(&tk_fast_mono, &snapshot->mono);
619 0 : snapshot->boot = snapshot->mono + ktime_to_ns(data_race(tk->offs_boot));
620 0 : }
621 :
622 : /**
623 : * halt_fast_timekeeper - Prevent fast timekeeper from accessing clocksource.
624 : * @tk: Timekeeper to snapshot.
625 : *
626 : * It generally is unsafe to access the clocksource after timekeeping has been
627 : * suspended, so take a snapshot of the readout base of @tk and use it as the
628 : * fast timekeeper's readout base while suspended. It will return the same
629 : * number of cycles every time until timekeeping is resumed at which time the
630 : * proper readout base for the fast timekeeper will be restored automatically.
631 : */
632 0 : static void halt_fast_timekeeper(const struct timekeeper *tk)
633 : {
634 0 : static struct tk_read_base tkr_dummy;
635 0 : const struct tk_read_base *tkr = &tk->tkr_mono;
636 :
637 0 : memcpy(&tkr_dummy, tkr, sizeof(tkr_dummy));
638 0 : cycles_at_suspend = tk_clock_read(tkr);
639 0 : tkr_dummy.clock = &dummy_clock;
640 0 : tkr_dummy.base_real = tkr->base + tk->offs_real;
641 0 : update_fast_timekeeper(&tkr_dummy, &tk_fast_mono);
642 :
643 0 : tkr = &tk->tkr_raw;
644 0 : memcpy(&tkr_dummy, tkr, sizeof(tkr_dummy));
645 0 : tkr_dummy.clock = &dummy_clock;
646 0 : update_fast_timekeeper(&tkr_dummy, &tk_fast_raw);
647 0 : }
648 :
649 : static RAW_NOTIFIER_HEAD(pvclock_gtod_chain);
650 :
651 7946 : static void update_pvclock_gtod(struct timekeeper *tk, bool was_set)
652 : {
653 7946 : raw_notifier_call_chain(&pvclock_gtod_chain, was_set, tk);
654 : }
655 :
656 : /**
657 : * pvclock_gtod_register_notifier - register a pvclock timedata update listener
658 : * @nb: Pointer to the notifier block to register
659 : */
660 0 : int pvclock_gtod_register_notifier(struct notifier_block *nb)
661 : {
662 0 : struct timekeeper *tk = &tk_core.timekeeper;
663 0 : unsigned long flags;
664 0 : int ret;
665 :
666 0 : raw_spin_lock_irqsave(&timekeeper_lock, flags);
667 0 : ret = raw_notifier_chain_register(&pvclock_gtod_chain, nb);
668 0 : update_pvclock_gtod(tk, true);
669 0 : raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
670 :
671 0 : return ret;
672 : }
673 : EXPORT_SYMBOL_GPL(pvclock_gtod_register_notifier);
674 :
675 : /**
676 : * pvclock_gtod_unregister_notifier - unregister a pvclock
677 : * timedata update listener
678 : * @nb: Pointer to the notifier block to unregister
679 : */
680 0 : int pvclock_gtod_unregister_notifier(struct notifier_block *nb)
681 : {
682 0 : unsigned long flags;
683 0 : int ret;
684 :
685 0 : raw_spin_lock_irqsave(&timekeeper_lock, flags);
686 0 : ret = raw_notifier_chain_unregister(&pvclock_gtod_chain, nb);
687 0 : raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
688 :
689 0 : return ret;
690 : }
691 : EXPORT_SYMBOL_GPL(pvclock_gtod_unregister_notifier);
692 :
693 : /*
694 : * tk_update_leap_state - helper to update the next_leap_ktime
695 : */
696 7946 : static inline void tk_update_leap_state(struct timekeeper *tk)
697 : {
698 7946 : tk->next_leap_ktime = ntp_get_next_leap();
699 7946 : if (tk->next_leap_ktime != KTIME_MAX)
700 : /* Convert to monotonic time */
701 0 : tk->next_leap_ktime = ktime_sub(tk->next_leap_ktime, tk->offs_real);
702 7946 : }
703 :
704 : /*
705 : * Update the ktime_t based scalar nsec members of the timekeeper
706 : */
707 7946 : static inline void tk_update_ktime_data(struct timekeeper *tk)
708 : {
709 7946 : u64 seconds;
710 7946 : u32 nsec;
711 :
712 : /*
713 : * The xtime based monotonic readout is:
714 : * nsec = (xtime_sec + wtm_sec) * 1e9 + wtm_nsec + now();
715 : * The ktime based monotonic readout is:
716 : * nsec = base_mono + now();
717 : * ==> base_mono = (xtime_sec + wtm_sec) * 1e9 + wtm_nsec
718 : */
719 7946 : seconds = (u64)(tk->xtime_sec + tk->wall_to_monotonic.tv_sec);
720 7946 : nsec = (u32) tk->wall_to_monotonic.tv_nsec;
721 7946 : tk->tkr_mono.base = ns_to_ktime(seconds * NSEC_PER_SEC + nsec);
722 :
723 : /*
724 : * The sum of the nanoseconds portions of xtime and
725 : * wall_to_monotonic can be greater/equal one second. Take
726 : * this into account before updating tk->ktime_sec.
727 : */
728 7946 : nsec += (u32)(tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift);
729 7946 : if (nsec >= NSEC_PER_SEC)
730 2431 : seconds++;
731 7946 : tk->ktime_sec = seconds;
732 :
733 : /* Update the monotonic raw base */
734 7946 : tk->tkr_raw.base = ns_to_ktime(tk->raw_sec * NSEC_PER_SEC);
735 7946 : }
736 :
737 : /* must hold timekeeper_lock */
738 7946 : static void timekeeping_update(struct timekeeper *tk, unsigned int action)
739 : {
740 7946 : if (action & TK_CLEAR_NTP) {
741 1 : tk->ntp_error = 0;
742 1 : ntp_clear();
743 : }
744 :
745 7946 : tk_update_leap_state(tk);
746 7946 : tk_update_ktime_data(tk);
747 :
748 7946 : update_vsyscall(tk);
749 7946 : update_pvclock_gtod(tk, action & TK_CLOCK_WAS_SET);
750 :
751 7946 : tk->tkr_mono.base_real = tk->tkr_mono.base + tk->offs_real;
752 7946 : update_fast_timekeeper(&tk->tkr_mono, &tk_fast_mono);
753 7946 : update_fast_timekeeper(&tk->tkr_raw, &tk_fast_raw);
754 :
755 7946 : if (action & TK_CLOCK_WAS_SET)
756 2 : tk->clock_was_set_seq++;
757 : /*
758 : * The mirroring of the data to the shadow-timekeeper needs
759 : * to happen last here to ensure we don't over-write the
760 : * timekeeper structure on the next update with stale data
761 : */
762 7946 : if (action & TK_MIRROR)
763 2 : memcpy(&shadow_timekeeper, &tk_core.timekeeper,
764 : sizeof(tk_core.timekeeper));
765 7946 : }
766 :
767 : /**
768 : * timekeeping_forward_now - update clock to the current time
769 : * @tk: Pointer to the timekeeper to update
770 : *
771 : * Forward the current clock to update its state since the last call to
772 : * update_wall_time(). This is useful before significant clock changes,
773 : * as it avoids having to deal with this time offset explicitly.
774 : */
775 1 : static void timekeeping_forward_now(struct timekeeper *tk)
776 : {
777 1 : u64 cycle_now, delta;
778 :
779 1 : cycle_now = tk_clock_read(&tk->tkr_mono);
780 1 : delta = clocksource_delta(cycle_now, tk->tkr_mono.cycle_last, tk->tkr_mono.mask);
781 1 : tk->tkr_mono.cycle_last = cycle_now;
782 1 : tk->tkr_raw.cycle_last = cycle_now;
783 :
784 1 : tk->tkr_mono.xtime_nsec += delta * tk->tkr_mono.mult;
785 1 : tk->tkr_raw.xtime_nsec += delta * tk->tkr_raw.mult;
786 :
787 1 : tk_normalize_xtime(tk);
788 1 : }
789 :
790 : /**
791 : * ktime_get_real_ts64 - Returns the time of day in a timespec64.
792 : * @ts: pointer to the timespec to be set
793 : *
794 : * Returns the time of day in a timespec64 (WARN if suspended).
795 : */
796 342 : void ktime_get_real_ts64(struct timespec64 *ts)
797 : {
798 342 : struct timekeeper *tk = &tk_core.timekeeper;
799 342 : unsigned int seq;
800 342 : u64 nsecs;
801 :
802 342 : WARN_ON(timekeeping_suspended);
803 :
804 342 : do {
805 342 : seq = read_seqcount_begin(&tk_core.seq);
806 :
807 342 : ts->tv_sec = tk->xtime_sec;
808 342 : nsecs = timekeeping_get_ns(&tk->tkr_mono);
809 :
810 342 : } while (read_seqcount_retry(&tk_core.seq, seq));
811 :
812 342 : ts->tv_nsec = 0;
813 342 : timespec64_add_ns(ts, nsecs);
814 342 : }
815 : EXPORT_SYMBOL(ktime_get_real_ts64);
816 :
817 107799 : ktime_t ktime_get(void)
818 : {
819 107799 : struct timekeeper *tk = &tk_core.timekeeper;
820 107799 : unsigned int seq;
821 107799 : ktime_t base;
822 107799 : u64 nsecs;
823 :
824 107799 : WARN_ON(timekeeping_suspended);
825 :
826 107936 : do {
827 268689 : seq = read_seqcount_begin(&tk_core.seq);
828 109932 : base = tk->tkr_mono.base;
829 109932 : nsecs = timekeeping_get_ns(&tk->tkr_mono);
830 :
831 110373 : } while (read_seqcount_retry(&tk_core.seq, seq));
832 :
833 110263 : return ktime_add_ns(base, nsecs);
834 : }
835 : EXPORT_SYMBOL_GPL(ktime_get);
836 :
837 0 : u32 ktime_get_resolution_ns(void)
838 : {
839 0 : struct timekeeper *tk = &tk_core.timekeeper;
840 0 : unsigned int seq;
841 0 : u32 nsecs;
842 :
843 0 : WARN_ON(timekeeping_suspended);
844 :
845 0 : do {
846 0 : seq = read_seqcount_begin(&tk_core.seq);
847 0 : nsecs = tk->tkr_mono.mult >> tk->tkr_mono.shift;
848 0 : } while (read_seqcount_retry(&tk_core.seq, seq));
849 :
850 0 : return nsecs;
851 : }
852 : EXPORT_SYMBOL_GPL(ktime_get_resolution_ns);
853 :
854 : static ktime_t *offsets[TK_OFFS_MAX] = {
855 : [TK_OFFS_REAL] = &tk_core.timekeeper.offs_real,
856 : [TK_OFFS_BOOT] = &tk_core.timekeeper.offs_boot,
857 : [TK_OFFS_TAI] = &tk_core.timekeeper.offs_tai,
858 : };
859 :
860 1635 : ktime_t ktime_get_with_offset(enum tk_offsets offs)
861 : {
862 1635 : struct timekeeper *tk = &tk_core.timekeeper;
863 1635 : unsigned int seq;
864 1635 : ktime_t base, *offset = offsets[offs];
865 1635 : u64 nsecs;
866 :
867 1635 : WARN_ON(timekeeping_suspended);
868 :
869 1635 : do {
870 1635 : seq = read_seqcount_begin(&tk_core.seq);
871 1635 : base = ktime_add(tk->tkr_mono.base, *offset);
872 1635 : nsecs = timekeeping_get_ns(&tk->tkr_mono);
873 :
874 1635 : } while (read_seqcount_retry(&tk_core.seq, seq));
875 :
876 1635 : return ktime_add_ns(base, nsecs);
877 :
878 : }
879 : EXPORT_SYMBOL_GPL(ktime_get_with_offset);
880 :
881 0 : ktime_t ktime_get_coarse_with_offset(enum tk_offsets offs)
882 : {
883 0 : struct timekeeper *tk = &tk_core.timekeeper;
884 0 : unsigned int seq;
885 0 : ktime_t base, *offset = offsets[offs];
886 0 : u64 nsecs;
887 :
888 0 : WARN_ON(timekeeping_suspended);
889 :
890 0 : do {
891 0 : seq = read_seqcount_begin(&tk_core.seq);
892 0 : base = ktime_add(tk->tkr_mono.base, *offset);
893 0 : nsecs = tk->tkr_mono.xtime_nsec >> tk->tkr_mono.shift;
894 :
895 0 : } while (read_seqcount_retry(&tk_core.seq, seq));
896 :
897 0 : return ktime_add_ns(base, nsecs);
898 : }
899 : EXPORT_SYMBOL_GPL(ktime_get_coarse_with_offset);
900 :
901 : /**
902 : * ktime_mono_to_any() - convert mononotic time to any other time
903 : * @tmono: time to convert.
904 : * @offs: which offset to use
905 : */
906 24 : ktime_t ktime_mono_to_any(ktime_t tmono, enum tk_offsets offs)
907 : {
908 24 : ktime_t *offset = offsets[offs];
909 24 : unsigned int seq;
910 24 : ktime_t tconv;
911 :
912 24 : do {
913 24 : seq = read_seqcount_begin(&tk_core.seq);
914 24 : tconv = ktime_add(tmono, *offset);
915 24 : } while (read_seqcount_retry(&tk_core.seq, seq));
916 :
917 24 : return tconv;
918 : }
919 : EXPORT_SYMBOL_GPL(ktime_mono_to_any);
920 :
921 : /**
922 : * ktime_get_raw - Returns the raw monotonic time in ktime_t format
923 : */
924 0 : ktime_t ktime_get_raw(void)
925 : {
926 0 : struct timekeeper *tk = &tk_core.timekeeper;
927 0 : unsigned int seq;
928 0 : ktime_t base;
929 0 : u64 nsecs;
930 :
931 0 : do {
932 0 : seq = read_seqcount_begin(&tk_core.seq);
933 0 : base = tk->tkr_raw.base;
934 0 : nsecs = timekeeping_get_ns(&tk->tkr_raw);
935 :
936 0 : } while (read_seqcount_retry(&tk_core.seq, seq));
937 :
938 0 : return ktime_add_ns(base, nsecs);
939 : }
940 : EXPORT_SYMBOL_GPL(ktime_get_raw);
941 :
942 : /**
943 : * ktime_get_ts64 - get the monotonic clock in timespec64 format
944 : * @ts: pointer to timespec variable
945 : *
946 : * The function calculates the monotonic clock from the realtime
947 : * clock and the wall_to_monotonic offset and stores the result
948 : * in normalized timespec64 format in the variable pointed to by @ts.
949 : */
950 802 : void ktime_get_ts64(struct timespec64 *ts)
951 : {
952 802 : struct timekeeper *tk = &tk_core.timekeeper;
953 802 : struct timespec64 tomono;
954 802 : unsigned int seq;
955 802 : u64 nsec;
956 :
957 802 : WARN_ON(timekeeping_suspended);
958 :
959 802 : do {
960 802 : seq = read_seqcount_begin(&tk_core.seq);
961 802 : ts->tv_sec = tk->xtime_sec;
962 802 : nsec = timekeeping_get_ns(&tk->tkr_mono);
963 802 : tomono = tk->wall_to_monotonic;
964 :
965 802 : } while (read_seqcount_retry(&tk_core.seq, seq));
966 :
967 802 : ts->tv_sec += tomono.tv_sec;
968 802 : ts->tv_nsec = 0;
969 802 : timespec64_add_ns(ts, nsec + tomono.tv_nsec);
970 802 : }
971 : EXPORT_SYMBOL_GPL(ktime_get_ts64);
972 :
973 : /**
974 : * ktime_get_seconds - Get the seconds portion of CLOCK_MONOTONIC
975 : *
976 : * Returns the seconds portion of CLOCK_MONOTONIC with a single non
977 : * serialized read. tk->ktime_sec is of type 'unsigned long' so this
978 : * works on both 32 and 64 bit systems. On 32 bit systems the readout
979 : * covers ~136 years of uptime which should be enough to prevent
980 : * premature wrap arounds.
981 : */
982 0 : time64_t ktime_get_seconds(void)
983 : {
984 0 : struct timekeeper *tk = &tk_core.timekeeper;
985 :
986 0 : WARN_ON(timekeeping_suspended);
987 0 : return tk->ktime_sec;
988 : }
989 : EXPORT_SYMBOL_GPL(ktime_get_seconds);
990 :
991 : /**
992 : * ktime_get_real_seconds - Get the seconds portion of CLOCK_REALTIME
993 : *
994 : * Returns the wall clock seconds since 1970.
995 : *
996 : * For 64bit systems the fast access to tk->xtime_sec is preserved. On
997 : * 32bit systems the access must be protected with the sequence
998 : * counter to provide "atomic" access to the 64bit tk->xtime_sec
999 : * value.
1000 : */
1001 432 : time64_t ktime_get_real_seconds(void)
1002 : {
1003 432 : struct timekeeper *tk = &tk_core.timekeeper;
1004 432 : time64_t seconds;
1005 432 : unsigned int seq;
1006 :
1007 432 : if (IS_ENABLED(CONFIG_64BIT))
1008 432 : return tk->xtime_sec;
1009 :
1010 : do {
1011 : seq = read_seqcount_begin(&tk_core.seq);
1012 : seconds = tk->xtime_sec;
1013 :
1014 : } while (read_seqcount_retry(&tk_core.seq, seq));
1015 :
1016 : return seconds;
1017 : }
1018 : EXPORT_SYMBOL_GPL(ktime_get_real_seconds);
1019 :
1020 : /**
1021 : * __ktime_get_real_seconds - The same as ktime_get_real_seconds
1022 : * but without the sequence counter protect. This internal function
1023 : * is called just when timekeeping lock is already held.
1024 : */
1025 0 : noinstr time64_t __ktime_get_real_seconds(void)
1026 : {
1027 0 : struct timekeeper *tk = &tk_core.timekeeper;
1028 :
1029 0 : return tk->xtime_sec;
1030 : }
1031 :
1032 : /**
1033 : * ktime_get_snapshot - snapshots the realtime/monotonic raw clocks with counter
1034 : * @systime_snapshot: pointer to struct receiving the system time snapshot
1035 : */
1036 0 : void ktime_get_snapshot(struct system_time_snapshot *systime_snapshot)
1037 : {
1038 0 : struct timekeeper *tk = &tk_core.timekeeper;
1039 0 : unsigned int seq;
1040 0 : ktime_t base_raw;
1041 0 : ktime_t base_real;
1042 0 : u64 nsec_raw;
1043 0 : u64 nsec_real;
1044 0 : u64 now;
1045 :
1046 0 : WARN_ON_ONCE(timekeeping_suspended);
1047 :
1048 0 : do {
1049 0 : seq = read_seqcount_begin(&tk_core.seq);
1050 0 : now = tk_clock_read(&tk->tkr_mono);
1051 0 : systime_snapshot->cs_was_changed_seq = tk->cs_was_changed_seq;
1052 0 : systime_snapshot->clock_was_set_seq = tk->clock_was_set_seq;
1053 0 : base_real = ktime_add(tk->tkr_mono.base,
1054 : tk_core.timekeeper.offs_real);
1055 0 : base_raw = tk->tkr_raw.base;
1056 0 : nsec_real = timekeeping_cycles_to_ns(&tk->tkr_mono, now);
1057 0 : nsec_raw = timekeeping_cycles_to_ns(&tk->tkr_raw, now);
1058 0 : } while (read_seqcount_retry(&tk_core.seq, seq));
1059 :
1060 0 : systime_snapshot->cycles = now;
1061 0 : systime_snapshot->real = ktime_add_ns(base_real, nsec_real);
1062 0 : systime_snapshot->raw = ktime_add_ns(base_raw, nsec_raw);
1063 0 : }
1064 : EXPORT_SYMBOL_GPL(ktime_get_snapshot);
1065 :
1066 : /* Scale base by mult/div checking for overflow */
1067 0 : static int scale64_check_overflow(u64 mult, u64 div, u64 *base)
1068 : {
1069 0 : u64 tmp, rem;
1070 :
1071 0 : tmp = div64_u64_rem(*base, div, &rem);
1072 :
1073 0 : if (((int)sizeof(u64)*8 - fls64(mult) < fls64(tmp)) ||
1074 0 : ((int)sizeof(u64)*8 - fls64(mult) < fls64(rem)))
1075 : return -EOVERFLOW;
1076 0 : tmp *= mult;
1077 :
1078 0 : rem = div64_u64(rem * mult, div);
1079 0 : *base = tmp + rem;
1080 0 : return 0;
1081 : }
1082 :
1083 : /**
1084 : * adjust_historical_crosststamp - adjust crosstimestamp previous to current interval
1085 : * @history: Snapshot representing start of history
1086 : * @partial_history_cycles: Cycle offset into history (fractional part)
1087 : * @total_history_cycles: Total history length in cycles
1088 : * @discontinuity: True indicates clock was set on history period
1089 : * @ts: Cross timestamp that should be adjusted using
1090 : * partial/total ratio
1091 : *
1092 : * Helper function used by get_device_system_crosststamp() to correct the
1093 : * crosstimestamp corresponding to the start of the current interval to the
1094 : * system counter value (timestamp point) provided by the driver. The
1095 : * total_history_* quantities are the total history starting at the provided
1096 : * reference point and ending at the start of the current interval. The cycle
1097 : * count between the driver timestamp point and the start of the current
1098 : * interval is partial_history_cycles.
1099 : */
1100 0 : static int adjust_historical_crosststamp(struct system_time_snapshot *history,
1101 : u64 partial_history_cycles,
1102 : u64 total_history_cycles,
1103 : bool discontinuity,
1104 : struct system_device_crosststamp *ts)
1105 : {
1106 0 : struct timekeeper *tk = &tk_core.timekeeper;
1107 0 : u64 corr_raw, corr_real;
1108 0 : bool interp_forward;
1109 0 : int ret;
1110 :
1111 0 : if (total_history_cycles == 0 || partial_history_cycles == 0)
1112 : return 0;
1113 :
1114 : /* Interpolate shortest distance from beginning or end of history */
1115 0 : interp_forward = partial_history_cycles > total_history_cycles / 2;
1116 0 : partial_history_cycles = interp_forward ?
1117 0 : total_history_cycles - partial_history_cycles :
1118 : partial_history_cycles;
1119 :
1120 : /*
1121 : * Scale the monotonic raw time delta by:
1122 : * partial_history_cycles / total_history_cycles
1123 : */
1124 0 : corr_raw = (u64)ktime_to_ns(
1125 0 : ktime_sub(ts->sys_monoraw, history->raw));
1126 0 : ret = scale64_check_overflow(partial_history_cycles,
1127 : total_history_cycles, &corr_raw);
1128 0 : if (ret)
1129 : return ret;
1130 :
1131 : /*
1132 : * If there is a discontinuity in the history, scale monotonic raw
1133 : * correction by:
1134 : * mult(real)/mult(raw) yielding the realtime correction
1135 : * Otherwise, calculate the realtime correction similar to monotonic
1136 : * raw calculation
1137 : */
1138 0 : if (discontinuity) {
1139 0 : corr_real = mul_u64_u32_div
1140 : (corr_raw, tk->tkr_mono.mult, tk->tkr_raw.mult);
1141 : } else {
1142 0 : corr_real = (u64)ktime_to_ns(
1143 0 : ktime_sub(ts->sys_realtime, history->real));
1144 0 : ret = scale64_check_overflow(partial_history_cycles,
1145 : total_history_cycles, &corr_real);
1146 0 : if (ret)
1147 : return ret;
1148 : }
1149 :
1150 : /* Fixup monotonic raw and real time time values */
1151 0 : if (interp_forward) {
1152 0 : ts->sys_monoraw = ktime_add_ns(history->raw, corr_raw);
1153 0 : ts->sys_realtime = ktime_add_ns(history->real, corr_real);
1154 : } else {
1155 0 : ts->sys_monoraw = ktime_sub_ns(ts->sys_monoraw, corr_raw);
1156 0 : ts->sys_realtime = ktime_sub_ns(ts->sys_realtime, corr_real);
1157 : }
1158 :
1159 : return 0;
1160 : }
1161 :
1162 : /*
1163 : * cycle_between - true if test occurs chronologically between before and after
1164 : */
1165 0 : static bool cycle_between(u64 before, u64 test, u64 after)
1166 : {
1167 0 : if (test > before && test < after)
1168 : return true;
1169 0 : if (test < before && before > after)
1170 : return true;
1171 : return false;
1172 : }
1173 :
1174 : /**
1175 : * get_device_system_crosststamp - Synchronously capture system/device timestamp
1176 : * @get_time_fn: Callback to get simultaneous device time and
1177 : * system counter from the device driver
1178 : * @ctx: Context passed to get_time_fn()
1179 : * @history_begin: Historical reference point used to interpolate system
1180 : * time when counter provided by the driver is before the current interval
1181 : * @xtstamp: Receives simultaneously captured system and device time
1182 : *
1183 : * Reads a timestamp from a device and correlates it to system time
1184 : */
1185 0 : int get_device_system_crosststamp(int (*get_time_fn)
1186 : (ktime_t *device_time,
1187 : struct system_counterval_t *sys_counterval,
1188 : void *ctx),
1189 : void *ctx,
1190 : struct system_time_snapshot *history_begin,
1191 : struct system_device_crosststamp *xtstamp)
1192 : {
1193 0 : struct system_counterval_t system_counterval;
1194 0 : struct timekeeper *tk = &tk_core.timekeeper;
1195 0 : u64 cycles, now, interval_start;
1196 0 : unsigned int clock_was_set_seq = 0;
1197 0 : ktime_t base_real, base_raw;
1198 0 : u64 nsec_real, nsec_raw;
1199 0 : u8 cs_was_changed_seq;
1200 0 : unsigned int seq;
1201 0 : bool do_interp;
1202 0 : int ret;
1203 :
1204 0 : do {
1205 0 : seq = read_seqcount_begin(&tk_core.seq);
1206 : /*
1207 : * Try to synchronously capture device time and a system
1208 : * counter value calling back into the device driver
1209 : */
1210 0 : ret = get_time_fn(&xtstamp->device, &system_counterval, ctx);
1211 0 : if (ret)
1212 0 : return ret;
1213 :
1214 : /*
1215 : * Verify that the clocksource associated with the captured
1216 : * system counter value is the same as the currently installed
1217 : * timekeeper clocksource
1218 : */
1219 0 : if (tk->tkr_mono.clock != system_counterval.cs)
1220 : return -ENODEV;
1221 0 : cycles = system_counterval.cycles;
1222 :
1223 : /*
1224 : * Check whether the system counter value provided by the
1225 : * device driver is on the current timekeeping interval.
1226 : */
1227 0 : now = tk_clock_read(&tk->tkr_mono);
1228 0 : interval_start = tk->tkr_mono.cycle_last;
1229 0 : if (!cycle_between(interval_start, cycles, now)) {
1230 0 : clock_was_set_seq = tk->clock_was_set_seq;
1231 0 : cs_was_changed_seq = tk->cs_was_changed_seq;
1232 0 : cycles = interval_start;
1233 0 : do_interp = true;
1234 : } else {
1235 : do_interp = false;
1236 : }
1237 :
1238 0 : base_real = ktime_add(tk->tkr_mono.base,
1239 : tk_core.timekeeper.offs_real);
1240 0 : base_raw = tk->tkr_raw.base;
1241 :
1242 0 : nsec_real = timekeeping_cycles_to_ns(&tk->tkr_mono,
1243 : system_counterval.cycles);
1244 0 : nsec_raw = timekeeping_cycles_to_ns(&tk->tkr_raw,
1245 : system_counterval.cycles);
1246 0 : } while (read_seqcount_retry(&tk_core.seq, seq));
1247 :
1248 0 : xtstamp->sys_realtime = ktime_add_ns(base_real, nsec_real);
1249 0 : xtstamp->sys_monoraw = ktime_add_ns(base_raw, nsec_raw);
1250 :
1251 : /*
1252 : * Interpolate if necessary, adjusting back from the start of the
1253 : * current interval
1254 : */
1255 0 : if (do_interp) {
1256 0 : u64 partial_history_cycles, total_history_cycles;
1257 0 : bool discontinuity;
1258 :
1259 : /*
1260 : * Check that the counter value occurs after the provided
1261 : * history reference and that the history doesn't cross a
1262 : * clocksource change
1263 : */
1264 0 : if (!history_begin ||
1265 0 : !cycle_between(history_begin->cycles,
1266 0 : system_counterval.cycles, cycles) ||
1267 0 : history_begin->cs_was_changed_seq != cs_was_changed_seq)
1268 : return -EINVAL;
1269 0 : partial_history_cycles = cycles - system_counterval.cycles;
1270 0 : total_history_cycles = cycles - history_begin->cycles;
1271 0 : discontinuity =
1272 0 : history_begin->clock_was_set_seq != clock_was_set_seq;
1273 :
1274 0 : ret = adjust_historical_crosststamp(history_begin,
1275 : partial_history_cycles,
1276 : total_history_cycles,
1277 : discontinuity, xtstamp);
1278 0 : if (ret)
1279 0 : return ret;
1280 : }
1281 :
1282 : return 0;
1283 : }
1284 : EXPORT_SYMBOL_GPL(get_device_system_crosststamp);
1285 :
1286 : /**
1287 : * do_settimeofday64 - Sets the time of day.
1288 : * @ts: pointer to the timespec64 variable containing the new time
1289 : *
1290 : * Sets the time of day to the new time and update NTP and notify hrtimers
1291 : */
1292 0 : int do_settimeofday64(const struct timespec64 *ts)
1293 : {
1294 0 : struct timekeeper *tk = &tk_core.timekeeper;
1295 0 : struct timespec64 ts_delta, xt;
1296 0 : unsigned long flags;
1297 0 : int ret = 0;
1298 :
1299 0 : if (!timespec64_valid_settod(ts))
1300 : return -EINVAL;
1301 :
1302 0 : raw_spin_lock_irqsave(&timekeeper_lock, flags);
1303 0 : write_seqcount_begin(&tk_core.seq);
1304 :
1305 0 : timekeeping_forward_now(tk);
1306 :
1307 0 : xt = tk_xtime(tk);
1308 0 : ts_delta.tv_sec = ts->tv_sec - xt.tv_sec;
1309 0 : ts_delta.tv_nsec = ts->tv_nsec - xt.tv_nsec;
1310 :
1311 0 : if (timespec64_compare(&tk->wall_to_monotonic, &ts_delta) > 0) {
1312 0 : ret = -EINVAL;
1313 0 : goto out;
1314 : }
1315 :
1316 0 : tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, ts_delta));
1317 :
1318 0 : tk_set_xtime(tk, ts);
1319 0 : out:
1320 0 : timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
1321 :
1322 0 : write_seqcount_end(&tk_core.seq);
1323 0 : raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1324 :
1325 : /* signal hrtimers about time change */
1326 0 : clock_was_set();
1327 :
1328 0 : if (!ret)
1329 : audit_tk_injoffset(ts_delta);
1330 :
1331 : return ret;
1332 : }
1333 : EXPORT_SYMBOL(do_settimeofday64);
1334 :
1335 : /**
1336 : * timekeeping_inject_offset - Adds or subtracts from the current time.
1337 : * @ts: Pointer to the timespec variable containing the offset
1338 : *
1339 : * Adds or subtracts an offset value from the current time.
1340 : */
1341 0 : static int timekeeping_inject_offset(const struct timespec64 *ts)
1342 : {
1343 0 : struct timekeeper *tk = &tk_core.timekeeper;
1344 0 : unsigned long flags;
1345 0 : struct timespec64 tmp;
1346 0 : int ret = 0;
1347 :
1348 0 : if (ts->tv_nsec < 0 || ts->tv_nsec >= NSEC_PER_SEC)
1349 : return -EINVAL;
1350 :
1351 0 : raw_spin_lock_irqsave(&timekeeper_lock, flags);
1352 0 : write_seqcount_begin(&tk_core.seq);
1353 :
1354 0 : timekeeping_forward_now(tk);
1355 :
1356 : /* Make sure the proposed value is valid */
1357 0 : tmp = timespec64_add(tk_xtime(tk), *ts);
1358 0 : if (timespec64_compare(&tk->wall_to_monotonic, ts) > 0 ||
1359 0 : !timespec64_valid_settod(&tmp)) {
1360 0 : ret = -EINVAL;
1361 0 : goto error;
1362 : }
1363 :
1364 0 : tk_xtime_add(tk, ts);
1365 0 : tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, *ts));
1366 :
1367 0 : error: /* even if we error out, we forwarded the time, so call update */
1368 0 : timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
1369 :
1370 0 : write_seqcount_end(&tk_core.seq);
1371 0 : raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1372 :
1373 : /* signal hrtimers about time change */
1374 0 : clock_was_set();
1375 :
1376 0 : return ret;
1377 : }
1378 :
1379 : /*
1380 : * Indicates if there is an offset between the system clock and the hardware
1381 : * clock/persistent clock/rtc.
1382 : */
1383 : int persistent_clock_is_local;
1384 :
1385 : /*
1386 : * Adjust the time obtained from the CMOS to be UTC time instead of
1387 : * local time.
1388 : *
1389 : * This is ugly, but preferable to the alternatives. Otherwise we
1390 : * would either need to write a program to do it in /etc/rc (and risk
1391 : * confusion if the program gets run more than once; it would also be
1392 : * hard to make the program warp the clock precisely n hours) or
1393 : * compile in the timezone information into the kernel. Bad, bad....
1394 : *
1395 : * - TYT, 1992-01-01
1396 : *
1397 : * The best thing to do is to keep the CMOS clock in universal time (UTC)
1398 : * as real UNIX machines always do it. This avoids all headaches about
1399 : * daylight saving times and warping kernel clocks.
1400 : */
1401 1 : void timekeeping_warp_clock(void)
1402 : {
1403 1 : if (sys_tz.tz_minuteswest != 0) {
1404 0 : struct timespec64 adjust;
1405 :
1406 0 : persistent_clock_is_local = 1;
1407 0 : adjust.tv_sec = sys_tz.tz_minuteswest * 60;
1408 0 : adjust.tv_nsec = 0;
1409 0 : timekeeping_inject_offset(&adjust);
1410 : }
1411 1 : }
1412 :
1413 : /*
1414 : * __timekeeping_set_tai_offset - Sets the TAI offset from UTC and monotonic
1415 : */
1416 0 : static void __timekeeping_set_tai_offset(struct timekeeper *tk, s32 tai_offset)
1417 : {
1418 0 : tk->tai_offset = tai_offset;
1419 0 : tk->offs_tai = ktime_add(tk->offs_real, ktime_set(tai_offset, 0));
1420 : }
1421 :
1422 : /*
1423 : * change_clocksource - Swaps clocksources if a new one is available
1424 : *
1425 : * Accumulates current time interval and initializes new clocksource
1426 : */
1427 1 : static int change_clocksource(void *data)
1428 : {
1429 1 : struct timekeeper *tk = &tk_core.timekeeper;
1430 1 : struct clocksource *new, *old;
1431 1 : unsigned long flags;
1432 :
1433 1 : new = (struct clocksource *) data;
1434 :
1435 1 : raw_spin_lock_irqsave(&timekeeper_lock, flags);
1436 2 : write_seqcount_begin(&tk_core.seq);
1437 :
1438 1 : timekeeping_forward_now(tk);
1439 : /*
1440 : * If the cs is in module, get a module reference. Succeeds
1441 : * for built-in code (owner == NULL) as well.
1442 : */
1443 1 : if (try_module_get(new->owner)) {
1444 1 : if (!new->enable || new->enable(new) == 0) {
1445 1 : old = tk->tkr_mono.clock;
1446 1 : tk_setup_internals(tk, new);
1447 1 : if (old->disable)
1448 0 : old->disable(old);
1449 1 : module_put(old->owner);
1450 : } else {
1451 1 : module_put(new->owner);
1452 : }
1453 : }
1454 1 : timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
1455 :
1456 1 : write_seqcount_end(&tk_core.seq);
1457 1 : raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1458 :
1459 1 : return 0;
1460 : }
1461 :
1462 : /**
1463 : * timekeeping_notify - Install a new clock source
1464 : * @clock: pointer to the clock source
1465 : *
1466 : * This function is called from clocksource.c after a new, better clock
1467 : * source has been registered. The caller holds the clocksource_mutex.
1468 : */
1469 1 : int timekeeping_notify(struct clocksource *clock)
1470 : {
1471 1 : struct timekeeper *tk = &tk_core.timekeeper;
1472 :
1473 1 : if (tk->tkr_mono.clock == clock)
1474 : return 0;
1475 1 : stop_machine(change_clocksource, clock, NULL);
1476 1 : tick_clock_notify();
1477 1 : return tk->tkr_mono.clock == clock ? 0 : -1;
1478 : }
1479 :
1480 : /**
1481 : * ktime_get_raw_ts64 - Returns the raw monotonic time in a timespec
1482 : * @ts: pointer to the timespec64 to be set
1483 : *
1484 : * Returns the raw monotonic time (completely un-modified by ntp)
1485 : */
1486 0 : void ktime_get_raw_ts64(struct timespec64 *ts)
1487 : {
1488 0 : struct timekeeper *tk = &tk_core.timekeeper;
1489 0 : unsigned int seq;
1490 0 : u64 nsecs;
1491 :
1492 0 : do {
1493 0 : seq = read_seqcount_begin(&tk_core.seq);
1494 0 : ts->tv_sec = tk->raw_sec;
1495 0 : nsecs = timekeeping_get_ns(&tk->tkr_raw);
1496 :
1497 0 : } while (read_seqcount_retry(&tk_core.seq, seq));
1498 :
1499 0 : ts->tv_nsec = 0;
1500 0 : timespec64_add_ns(ts, nsecs);
1501 0 : }
1502 : EXPORT_SYMBOL(ktime_get_raw_ts64);
1503 :
1504 :
1505 : /**
1506 : * timekeeping_valid_for_hres - Check if timekeeping is suitable for hres
1507 : */
1508 8 : int timekeeping_valid_for_hres(void)
1509 : {
1510 8 : struct timekeeper *tk = &tk_core.timekeeper;
1511 8 : unsigned int seq;
1512 8 : int ret;
1513 :
1514 8 : do {
1515 8 : seq = read_seqcount_begin(&tk_core.seq);
1516 :
1517 8 : ret = tk->tkr_mono.clock->flags & CLOCK_SOURCE_VALID_FOR_HRES;
1518 :
1519 8 : } while (read_seqcount_retry(&tk_core.seq, seq));
1520 :
1521 8 : return ret;
1522 : }
1523 :
1524 : /**
1525 : * timekeeping_max_deferment - Returns max time the clocksource can be deferred
1526 : */
1527 1174 : u64 timekeeping_max_deferment(void)
1528 : {
1529 1174 : struct timekeeper *tk = &tk_core.timekeeper;
1530 1174 : unsigned int seq;
1531 1174 : u64 ret;
1532 :
1533 1174 : do {
1534 1174 : seq = read_seqcount_begin(&tk_core.seq);
1535 :
1536 1182 : ret = tk->tkr_mono.clock->max_idle_ns;
1537 :
1538 1182 : } while (read_seqcount_retry(&tk_core.seq, seq));
1539 :
1540 1182 : return ret;
1541 : }
1542 :
1543 : /**
1544 : * read_persistent_clock64 - Return time from the persistent clock.
1545 : * @ts: Pointer to the storage for the readout value
1546 : *
1547 : * Weak dummy function for arches that do not yet support it.
1548 : * Reads the time from the battery backed persistent clock.
1549 : * Returns a timespec with tv_sec=0 and tv_nsec=0 if unsupported.
1550 : *
1551 : * XXX - Do be sure to remove it once all arches implement it.
1552 : */
1553 0 : void __weak read_persistent_clock64(struct timespec64 *ts)
1554 : {
1555 0 : ts->tv_sec = 0;
1556 0 : ts->tv_nsec = 0;
1557 0 : }
1558 :
1559 : /**
1560 : * read_persistent_wall_and_boot_offset - Read persistent clock, and also offset
1561 : * from the boot.
1562 : *
1563 : * Weak dummy function for arches that do not yet support it.
1564 : * @wall_time: - current time as returned by persistent clock
1565 : * @boot_offset: - offset that is defined as wall_time - boot_time
1566 : *
1567 : * The default function calculates offset based on the current value of
1568 : * local_clock(). This way architectures that support sched_clock() but don't
1569 : * support dedicated boot time clock will provide the best estimate of the
1570 : * boot time.
1571 : */
1572 : void __weak __init
1573 1 : read_persistent_wall_and_boot_offset(struct timespec64 *wall_time,
1574 : struct timespec64 *boot_offset)
1575 : {
1576 1 : read_persistent_clock64(wall_time);
1577 2 : *boot_offset = ns_to_timespec64(local_clock());
1578 1 : }
1579 :
1580 : /*
1581 : * Flag reflecting whether timekeeping_resume() has injected sleeptime.
1582 : *
1583 : * The flag starts of false and is only set when a suspend reaches
1584 : * timekeeping_suspend(), timekeeping_resume() sets it to false when the
1585 : * timekeeper clocksource is not stopping across suspend and has been
1586 : * used to update sleep time. If the timekeeper clocksource has stopped
1587 : * then the flag stays true and is used by the RTC resume code to decide
1588 : * whether sleeptime must be injected and if so the flag gets false then.
1589 : *
1590 : * If a suspend fails before reaching timekeeping_resume() then the flag
1591 : * stays false and prevents erroneous sleeptime injection.
1592 : */
1593 : static bool suspend_timing_needed;
1594 :
1595 : /* Flag for if there is a persistent clock on this platform */
1596 : static bool persistent_clock_exists;
1597 :
1598 : /*
1599 : * timekeeping_init - Initializes the clocksource and common timekeeping values
1600 : */
1601 1 : void __init timekeeping_init(void)
1602 : {
1603 1 : struct timespec64 wall_time, boot_offset, wall_to_mono;
1604 1 : struct timekeeper *tk = &tk_core.timekeeper;
1605 1 : struct clocksource *clock;
1606 1 : unsigned long flags;
1607 :
1608 1 : read_persistent_wall_and_boot_offset(&wall_time, &boot_offset);
1609 2 : if (timespec64_valid_settod(&wall_time) &&
1610 1 : timespec64_to_ns(&wall_time) > 0) {
1611 1 : persistent_clock_exists = true;
1612 0 : } else if (timespec64_to_ns(&wall_time) != 0) {
1613 0 : pr_warn("Persistent clock returned invalid value");
1614 0 : wall_time = (struct timespec64){0};
1615 : }
1616 :
1617 1 : if (timespec64_compare(&wall_time, &boot_offset) < 0)
1618 0 : boot_offset = (struct timespec64){0};
1619 :
1620 : /*
1621 : * We want set wall_to_mono, so the following is true:
1622 : * wall time + wall_to_mono = boot time
1623 : */
1624 1 : wall_to_mono = timespec64_sub(boot_offset, wall_time);
1625 :
1626 1 : raw_spin_lock_irqsave(&timekeeper_lock, flags);
1627 2 : write_seqcount_begin(&tk_core.seq);
1628 1 : ntp_init();
1629 :
1630 1 : clock = clocksource_default_clock();
1631 1 : if (clock->enable)
1632 0 : clock->enable(clock);
1633 1 : tk_setup_internals(tk, clock);
1634 :
1635 1 : tk_set_xtime(tk, &wall_time);
1636 1 : tk->raw_sec = 0;
1637 :
1638 1 : tk_set_wall_to_mono(tk, wall_to_mono);
1639 :
1640 1 : timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
1641 :
1642 1 : write_seqcount_end(&tk_core.seq);
1643 1 : raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1644 1 : }
1645 :
1646 : /* time in seconds when suspend began for persistent clock */
1647 : static struct timespec64 timekeeping_suspend_time;
1648 :
1649 : /**
1650 : * __timekeeping_inject_sleeptime - Internal function to add sleep interval
1651 : * @tk: Pointer to the timekeeper to be updated
1652 : * @delta: Pointer to the delta value in timespec64 format
1653 : *
1654 : * Takes a timespec offset measuring a suspend interval and properly
1655 : * adds the sleep offset to the timekeeping variables.
1656 : */
1657 0 : static void __timekeeping_inject_sleeptime(struct timekeeper *tk,
1658 : const struct timespec64 *delta)
1659 : {
1660 0 : if (!timespec64_valid_strict(delta)) {
1661 0 : printk_deferred(KERN_WARNING
1662 : "__timekeeping_inject_sleeptime: Invalid "
1663 : "sleep delta value!\n");
1664 0 : return;
1665 : }
1666 0 : tk_xtime_add(tk, delta);
1667 0 : tk_set_wall_to_mono(tk, timespec64_sub(tk->wall_to_monotonic, *delta));
1668 0 : tk_update_sleep_time(tk, timespec64_to_ktime(*delta));
1669 0 : tk_debug_account_sleep_time(delta);
1670 : }
1671 :
1672 : #if defined(CONFIG_PM_SLEEP) && defined(CONFIG_RTC_HCTOSYS_DEVICE)
1673 : /**
1674 : * We have three kinds of time sources to use for sleep time
1675 : * injection, the preference order is:
1676 : * 1) non-stop clocksource
1677 : * 2) persistent clock (ie: RTC accessible when irqs are off)
1678 : * 3) RTC
1679 : *
1680 : * 1) and 2) are used by timekeeping, 3) by RTC subsystem.
1681 : * If system has neither 1) nor 2), 3) will be used finally.
1682 : *
1683 : *
1684 : * If timekeeping has injected sleeptime via either 1) or 2),
1685 : * 3) becomes needless, so in this case we don't need to call
1686 : * rtc_resume(), and this is what timekeeping_rtc_skipresume()
1687 : * means.
1688 : */
1689 : bool timekeeping_rtc_skipresume(void)
1690 : {
1691 : return !suspend_timing_needed;
1692 : }
1693 :
1694 : /**
1695 : * 1) can be determined whether to use or not only when doing
1696 : * timekeeping_resume() which is invoked after rtc_suspend(),
1697 : * so we can't skip rtc_suspend() surely if system has 1).
1698 : *
1699 : * But if system has 2), 2) will definitely be used, so in this
1700 : * case we don't need to call rtc_suspend(), and this is what
1701 : * timekeeping_rtc_skipsuspend() means.
1702 : */
1703 : bool timekeeping_rtc_skipsuspend(void)
1704 : {
1705 : return persistent_clock_exists;
1706 : }
1707 :
1708 : /**
1709 : * timekeeping_inject_sleeptime64 - Adds suspend interval to timeekeeping values
1710 : * @delta: pointer to a timespec64 delta value
1711 : *
1712 : * This hook is for architectures that cannot support read_persistent_clock64
1713 : * because their RTC/persistent clock is only accessible when irqs are enabled.
1714 : * and also don't have an effective nonstop clocksource.
1715 : *
1716 : * This function should only be called by rtc_resume(), and allows
1717 : * a suspend offset to be injected into the timekeeping values.
1718 : */
1719 : void timekeeping_inject_sleeptime64(const struct timespec64 *delta)
1720 : {
1721 : struct timekeeper *tk = &tk_core.timekeeper;
1722 : unsigned long flags;
1723 :
1724 : raw_spin_lock_irqsave(&timekeeper_lock, flags);
1725 : write_seqcount_begin(&tk_core.seq);
1726 :
1727 : suspend_timing_needed = false;
1728 :
1729 : timekeeping_forward_now(tk);
1730 :
1731 : __timekeeping_inject_sleeptime(tk, delta);
1732 :
1733 : timekeeping_update(tk, TK_CLEAR_NTP | TK_MIRROR | TK_CLOCK_WAS_SET);
1734 :
1735 : write_seqcount_end(&tk_core.seq);
1736 : raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1737 :
1738 : /* signal hrtimers about time change */
1739 : clock_was_set();
1740 : }
1741 : #endif
1742 :
1743 : /**
1744 : * timekeeping_resume - Resumes the generic timekeeping subsystem.
1745 : */
1746 0 : void timekeeping_resume(void)
1747 : {
1748 0 : struct timekeeper *tk = &tk_core.timekeeper;
1749 0 : struct clocksource *clock = tk->tkr_mono.clock;
1750 0 : unsigned long flags;
1751 0 : struct timespec64 ts_new, ts_delta;
1752 0 : u64 cycle_now, nsec;
1753 0 : bool inject_sleeptime = false;
1754 :
1755 0 : read_persistent_clock64(&ts_new);
1756 :
1757 0 : clockevents_resume();
1758 0 : clocksource_resume();
1759 :
1760 0 : raw_spin_lock_irqsave(&timekeeper_lock, flags);
1761 0 : write_seqcount_begin(&tk_core.seq);
1762 :
1763 : /*
1764 : * After system resumes, we need to calculate the suspended time and
1765 : * compensate it for the OS time. There are 3 sources that could be
1766 : * used: Nonstop clocksource during suspend, persistent clock and rtc
1767 : * device.
1768 : *
1769 : * One specific platform may have 1 or 2 or all of them, and the
1770 : * preference will be:
1771 : * suspend-nonstop clocksource -> persistent clock -> rtc
1772 : * The less preferred source will only be tried if there is no better
1773 : * usable source. The rtc part is handled separately in rtc core code.
1774 : */
1775 0 : cycle_now = tk_clock_read(&tk->tkr_mono);
1776 0 : nsec = clocksource_stop_suspend_timing(clock, cycle_now);
1777 0 : if (nsec > 0) {
1778 0 : ts_delta = ns_to_timespec64(nsec);
1779 0 : inject_sleeptime = true;
1780 0 : } else if (timespec64_compare(&ts_new, &timekeeping_suspend_time) > 0) {
1781 0 : ts_delta = timespec64_sub(ts_new, timekeeping_suspend_time);
1782 0 : inject_sleeptime = true;
1783 : }
1784 :
1785 0 : if (inject_sleeptime) {
1786 0 : suspend_timing_needed = false;
1787 0 : __timekeeping_inject_sleeptime(tk, &ts_delta);
1788 : }
1789 :
1790 : /* Re-base the last cycle value */
1791 0 : tk->tkr_mono.cycle_last = cycle_now;
1792 0 : tk->tkr_raw.cycle_last = cycle_now;
1793 :
1794 0 : tk->ntp_error = 0;
1795 0 : timekeeping_suspended = 0;
1796 0 : timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
1797 0 : write_seqcount_end(&tk_core.seq);
1798 0 : raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1799 :
1800 0 : touch_softlockup_watchdog();
1801 :
1802 0 : tick_resume();
1803 0 : hrtimers_resume();
1804 0 : }
1805 :
1806 0 : int timekeeping_suspend(void)
1807 : {
1808 0 : struct timekeeper *tk = &tk_core.timekeeper;
1809 0 : unsigned long flags;
1810 0 : struct timespec64 delta, delta_delta;
1811 0 : static struct timespec64 old_delta;
1812 0 : struct clocksource *curr_clock;
1813 0 : u64 cycle_now;
1814 :
1815 0 : read_persistent_clock64(&timekeeping_suspend_time);
1816 :
1817 : /*
1818 : * On some systems the persistent_clock can not be detected at
1819 : * timekeeping_init by its return value, so if we see a valid
1820 : * value returned, update the persistent_clock_exists flag.
1821 : */
1822 0 : if (timekeeping_suspend_time.tv_sec || timekeeping_suspend_time.tv_nsec)
1823 0 : persistent_clock_exists = true;
1824 :
1825 0 : suspend_timing_needed = true;
1826 :
1827 0 : raw_spin_lock_irqsave(&timekeeper_lock, flags);
1828 0 : write_seqcount_begin(&tk_core.seq);
1829 0 : timekeeping_forward_now(tk);
1830 0 : timekeeping_suspended = 1;
1831 :
1832 : /*
1833 : * Since we've called forward_now, cycle_last stores the value
1834 : * just read from the current clocksource. Save this to potentially
1835 : * use in suspend timing.
1836 : */
1837 0 : curr_clock = tk->tkr_mono.clock;
1838 0 : cycle_now = tk->tkr_mono.cycle_last;
1839 0 : clocksource_start_suspend_timing(curr_clock, cycle_now);
1840 :
1841 0 : if (persistent_clock_exists) {
1842 : /*
1843 : * To avoid drift caused by repeated suspend/resumes,
1844 : * which each can add ~1 second drift error,
1845 : * try to compensate so the difference in system time
1846 : * and persistent_clock time stays close to constant.
1847 : */
1848 0 : delta = timespec64_sub(tk_xtime(tk), timekeeping_suspend_time);
1849 0 : delta_delta = timespec64_sub(delta, old_delta);
1850 0 : if (abs(delta_delta.tv_sec) >= 2) {
1851 : /*
1852 : * if delta_delta is too large, assume time correction
1853 : * has occurred and set old_delta to the current delta.
1854 : */
1855 0 : old_delta = delta;
1856 : } else {
1857 : /* Otherwise try to adjust old_system to compensate */
1858 0 : timekeeping_suspend_time =
1859 0 : timespec64_add(timekeeping_suspend_time, delta_delta);
1860 : }
1861 : }
1862 :
1863 0 : timekeeping_update(tk, TK_MIRROR);
1864 0 : halt_fast_timekeeper(tk);
1865 0 : write_seqcount_end(&tk_core.seq);
1866 0 : raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
1867 :
1868 0 : tick_suspend();
1869 0 : clocksource_suspend();
1870 0 : clockevents_suspend();
1871 :
1872 0 : return 0;
1873 : }
1874 :
1875 : /* sysfs resume/suspend bits for timekeeping */
1876 : static struct syscore_ops timekeeping_syscore_ops = {
1877 : .resume = timekeeping_resume,
1878 : .suspend = timekeeping_suspend,
1879 : };
1880 :
1881 1 : static int __init timekeeping_init_ops(void)
1882 : {
1883 1 : register_syscore_ops(&timekeeping_syscore_ops);
1884 1 : return 0;
1885 : }
1886 : device_initcall(timekeeping_init_ops);
1887 :
1888 : /*
1889 : * Apply a multiplier adjustment to the timekeeper
1890 : */
1891 7943 : static __always_inline void timekeeping_apply_adjustment(struct timekeeper *tk,
1892 : s64 offset,
1893 : s32 mult_adj)
1894 : {
1895 7943 : s64 interval = tk->cycle_interval;
1896 :
1897 7943 : if (mult_adj == 0) {
1898 : return;
1899 0 : } else if (mult_adj == -1) {
1900 0 : interval = -interval;
1901 0 : offset = -offset;
1902 0 : } else if (mult_adj != 1) {
1903 0 : interval *= mult_adj;
1904 0 : offset *= mult_adj;
1905 : }
1906 :
1907 : /*
1908 : * So the following can be confusing.
1909 : *
1910 : * To keep things simple, lets assume mult_adj == 1 for now.
1911 : *
1912 : * When mult_adj != 1, remember that the interval and offset values
1913 : * have been appropriately scaled so the math is the same.
1914 : *
1915 : * The basic idea here is that we're increasing the multiplier
1916 : * by one, this causes the xtime_interval to be incremented by
1917 : * one cycle_interval. This is because:
1918 : * xtime_interval = cycle_interval * mult
1919 : * So if mult is being incremented by one:
1920 : * xtime_interval = cycle_interval * (mult + 1)
1921 : * Its the same as:
1922 : * xtime_interval = (cycle_interval * mult) + cycle_interval
1923 : * Which can be shortened to:
1924 : * xtime_interval += cycle_interval
1925 : *
1926 : * So offset stores the non-accumulated cycles. Thus the current
1927 : * time (in shifted nanoseconds) is:
1928 : * now = (offset * adj) + xtime_nsec
1929 : * Now, even though we're adjusting the clock frequency, we have
1930 : * to keep time consistent. In other words, we can't jump back
1931 : * in time, and we also want to avoid jumping forward in time.
1932 : *
1933 : * So given the same offset value, we need the time to be the same
1934 : * both before and after the freq adjustment.
1935 : * now = (offset * adj_1) + xtime_nsec_1
1936 : * now = (offset * adj_2) + xtime_nsec_2
1937 : * So:
1938 : * (offset * adj_1) + xtime_nsec_1 =
1939 : * (offset * adj_2) + xtime_nsec_2
1940 : * And we know:
1941 : * adj_2 = adj_1 + 1
1942 : * So:
1943 : * (offset * adj_1) + xtime_nsec_1 =
1944 : * (offset * (adj_1+1)) + xtime_nsec_2
1945 : * (offset * adj_1) + xtime_nsec_1 =
1946 : * (offset * adj_1) + offset + xtime_nsec_2
1947 : * Canceling the sides:
1948 : * xtime_nsec_1 = offset + xtime_nsec_2
1949 : * Which gives us:
1950 : * xtime_nsec_2 = xtime_nsec_1 - offset
1951 : * Which simplfies to:
1952 : * xtime_nsec -= offset
1953 : */
1954 0 : if ((mult_adj > 0) && (tk->tkr_mono.mult + mult_adj < mult_adj)) {
1955 : /* NTP adjustment caused clocksource mult overflow */
1956 0 : WARN_ON_ONCE(1);
1957 0 : return;
1958 : }
1959 :
1960 0 : tk->tkr_mono.mult += mult_adj;
1961 0 : tk->xtime_interval += interval;
1962 0 : tk->tkr_mono.xtime_nsec -= offset;
1963 : }
1964 :
1965 : /*
1966 : * Adjust the timekeeper's multiplier to the correct frequency
1967 : * and also to reduce the accumulated error value.
1968 : */
1969 7943 : static void timekeeping_adjust(struct timekeeper *tk, s64 offset)
1970 : {
1971 7943 : u32 mult;
1972 :
1973 : /*
1974 : * Determine the multiplier from the current NTP tick length.
1975 : * Avoid expensive division when the tick length doesn't change.
1976 : */
1977 7943 : if (likely(tk->ntp_tick == ntp_tick_length())) {
1978 7943 : mult = tk->tkr_mono.mult - tk->ntp_err_mult;
1979 : } else {
1980 0 : tk->ntp_tick = ntp_tick_length();
1981 0 : mult = div64_u64((tk->ntp_tick >> tk->ntp_error_shift) -
1982 0 : tk->xtime_remainder, tk->cycle_interval);
1983 : }
1984 :
1985 : /*
1986 : * If the clock is behind the NTP time, increase the multiplier by 1
1987 : * to catch up with it. If it's ahead and there was a remainder in the
1988 : * tick division, the clock will slow down. Otherwise it will stay
1989 : * ahead until the tick length changes to a non-divisible value.
1990 : */
1991 7943 : tk->ntp_err_mult = tk->ntp_error > 0 ? 1 : 0;
1992 7943 : mult += tk->ntp_err_mult;
1993 :
1994 7943 : timekeeping_apply_adjustment(tk, offset, mult - tk->tkr_mono.mult);
1995 :
1996 7943 : if (unlikely(tk->tkr_mono.clock->maxadj &&
1997 : (abs(tk->tkr_mono.mult - tk->tkr_mono.clock->mult)
1998 : > tk->tkr_mono.clock->maxadj))) {
1999 0 : printk_once(KERN_WARNING
2000 : "Adjusting %s more than 11%% (%ld vs %ld)\n",
2001 : tk->tkr_mono.clock->name, (long)tk->tkr_mono.mult,
2002 : (long)tk->tkr_mono.clock->mult + tk->tkr_mono.clock->maxadj);
2003 : }
2004 :
2005 : /*
2006 : * It may be possible that when we entered this function, xtime_nsec
2007 : * was very small. Further, if we're slightly speeding the clocksource
2008 : * in the code above, its possible the required corrective factor to
2009 : * xtime_nsec could cause it to underflow.
2010 : *
2011 : * Now, since we have already accumulated the second and the NTP
2012 : * subsystem has been notified via second_overflow(), we need to skip
2013 : * the next update.
2014 : */
2015 7943 : if (unlikely((s64)tk->tkr_mono.xtime_nsec < 0)) {
2016 0 : tk->tkr_mono.xtime_nsec += (u64)NSEC_PER_SEC <<
2017 0 : tk->tkr_mono.shift;
2018 0 : tk->xtime_sec--;
2019 0 : tk->skip_second_overflow = 1;
2020 : }
2021 7943 : }
2022 :
2023 : /*
2024 : * accumulate_nsecs_to_secs - Accumulates nsecs into secs
2025 : *
2026 : * Helper function that accumulates the nsecs greater than a second
2027 : * from the xtime_nsec field to the xtime_secs field.
2028 : * It also calls into the NTP code to handle leapsecond processing.
2029 : */
2030 15915 : static inline unsigned int accumulate_nsecs_to_secs(struct timekeeper *tk)
2031 : {
2032 15915 : u64 nsecps = (u64)NSEC_PER_SEC << tk->tkr_mono.shift;
2033 15915 : unsigned int clock_set = 0;
2034 :
2035 15950 : while (tk->tkr_mono.xtime_nsec >= nsecps) {
2036 35 : int leap;
2037 :
2038 35 : tk->tkr_mono.xtime_nsec -= nsecps;
2039 35 : tk->xtime_sec++;
2040 :
2041 : /*
2042 : * Skip NTP update if this second was accumulated before,
2043 : * i.e. xtime_nsec underflowed in timekeeping_adjust()
2044 : */
2045 35 : if (unlikely(tk->skip_second_overflow)) {
2046 0 : tk->skip_second_overflow = 0;
2047 0 : continue;
2048 : }
2049 :
2050 : /* Figure out if its a leap sec and apply if needed */
2051 35 : leap = second_overflow(tk->xtime_sec);
2052 35 : if (unlikely(leap)) {
2053 0 : struct timespec64 ts;
2054 :
2055 0 : tk->xtime_sec += leap;
2056 :
2057 0 : ts.tv_sec = leap;
2058 0 : ts.tv_nsec = 0;
2059 0 : tk_set_wall_to_mono(tk,
2060 : timespec64_sub(tk->wall_to_monotonic, ts));
2061 :
2062 0 : __timekeeping_set_tai_offset(tk, tk->tai_offset - leap);
2063 :
2064 0 : clock_set = TK_CLOCK_WAS_SET;
2065 : }
2066 : }
2067 15915 : return clock_set;
2068 : }
2069 :
2070 : /*
2071 : * logarithmic_accumulation - shifted accumulation of cycles
2072 : *
2073 : * This functions accumulates a shifted interval of cycles into
2074 : * a shifted interval nanoseconds. Allows for O(log) accumulation
2075 : * loop.
2076 : *
2077 : * Returns the unconsumed cycles.
2078 : */
2079 8252 : static u64 logarithmic_accumulation(struct timekeeper *tk, u64 offset,
2080 : u32 shift, unsigned int *clock_set)
2081 : {
2082 8252 : u64 interval = tk->cycle_interval << shift;
2083 8252 : u64 snsec_per_sec;
2084 :
2085 : /* If the offset is smaller than a shifted interval, do nothing */
2086 8252 : if (offset < interval)
2087 : return offset;
2088 :
2089 : /* Accumulate one shifted interval */
2090 7972 : offset -= interval;
2091 7972 : tk->tkr_mono.cycle_last += interval;
2092 7972 : tk->tkr_raw.cycle_last += interval;
2093 :
2094 7972 : tk->tkr_mono.xtime_nsec += tk->xtime_interval << shift;
2095 7972 : *clock_set |= accumulate_nsecs_to_secs(tk);
2096 :
2097 : /* Accumulate raw time */
2098 7972 : tk->tkr_raw.xtime_nsec += tk->raw_interval << shift;
2099 7972 : snsec_per_sec = (u64)NSEC_PER_SEC << tk->tkr_raw.shift;
2100 8006 : while (tk->tkr_raw.xtime_nsec >= snsec_per_sec) {
2101 34 : tk->tkr_raw.xtime_nsec -= snsec_per_sec;
2102 34 : tk->raw_sec++;
2103 : }
2104 :
2105 : /* Accumulate error between NTP and clock interval */
2106 7972 : tk->ntp_error += tk->ntp_tick << shift;
2107 7972 : tk->ntp_error -= (tk->xtime_interval + tk->xtime_remainder) <<
2108 7972 : (tk->ntp_error_shift + shift);
2109 :
2110 7972 : return offset;
2111 : }
2112 :
2113 : /*
2114 : * timekeeping_advance - Updates the timekeeper to the current time and
2115 : * current NTP tick length
2116 : */
2117 7945 : static void timekeeping_advance(enum timekeeping_adv_mode mode)
2118 : {
2119 7945 : struct timekeeper *real_tk = &tk_core.timekeeper;
2120 7945 : struct timekeeper *tk = &shadow_timekeeper;
2121 7945 : u64 offset;
2122 7945 : int shift = 0, maxshift;
2123 7945 : unsigned int clock_set = 0;
2124 7945 : unsigned long flags;
2125 :
2126 7945 : raw_spin_lock_irqsave(&timekeeper_lock, flags);
2127 :
2128 : /* Make sure we're fully resumed: */
2129 7945 : if (unlikely(timekeeping_suspended))
2130 0 : goto out;
2131 :
2132 7945 : offset = clocksource_delta(tk_clock_read(&tk->tkr_mono),
2133 : tk->tkr_mono.cycle_last, tk->tkr_mono.mask);
2134 :
2135 : /* Check if there's really nothing to do */
2136 7945 : if (offset < real_tk->cycle_interval && mode == TK_ADV_TICK)
2137 2 : goto out;
2138 :
2139 : /* Do some additional sanity checking */
2140 7943 : timekeeping_check_update(tk, offset);
2141 :
2142 : /*
2143 : * With NO_HZ we may have to accumulate many cycle_intervals
2144 : * (think "ticks") worth of time at once. To do this efficiently,
2145 : * we calculate the largest doubling multiple of cycle_intervals
2146 : * that is smaller than the offset. We then accumulate that
2147 : * chunk in one go, and then try to consume the next smaller
2148 : * doubled multiple.
2149 : */
2150 7943 : shift = ilog2(offset) - ilog2(tk->cycle_interval);
2151 7943 : shift = max(0, shift);
2152 : /* Bound shift to one less than what overflows tick_length */
2153 7943 : maxshift = (64 - (ilog2(ntp_tick_length())+1)) - 1;
2154 7943 : shift = min(shift, maxshift);
2155 16195 : while (offset >= tk->cycle_interval) {
2156 8252 : offset = logarithmic_accumulation(tk, offset, shift,
2157 : &clock_set);
2158 8252 : if (offset < tk->cycle_interval<<shift)
2159 8252 : shift--;
2160 : }
2161 :
2162 : /* Adjust the multiplier to correct NTP error */
2163 7943 : timekeeping_adjust(tk, offset);
2164 :
2165 : /*
2166 : * Finally, make sure that after the rounding
2167 : * xtime_nsec isn't larger than NSEC_PER_SEC
2168 : */
2169 7943 : clock_set |= accumulate_nsecs_to_secs(tk);
2170 :
2171 15886 : write_seqcount_begin(&tk_core.seq);
2172 : /*
2173 : * Update the real timekeeper.
2174 : *
2175 : * We could avoid this memcpy by switching pointers, but that
2176 : * requires changes to all other timekeeper usage sites as
2177 : * well, i.e. move the timekeeper pointer getter into the
2178 : * spinlocked/seqcount protected sections. And we trade this
2179 : * memcpy under the tk_core.seq against one before we start
2180 : * updating.
2181 : */
2182 7943 : timekeeping_update(tk, clock_set);
2183 7943 : memcpy(real_tk, tk, sizeof(*tk));
2184 : /* The memcpy must come last. Do not put anything here! */
2185 7943 : write_seqcount_end(&tk_core.seq);
2186 7943 : out:
2187 7945 : raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
2188 7945 : if (clock_set)
2189 : /* Have to call _delayed version, since in irq context*/
2190 : clock_was_set_delayed();
2191 7945 : }
2192 :
2193 : /**
2194 : * update_wall_time - Uses the current clocksource to increment the wall time
2195 : *
2196 : */
2197 7945 : void update_wall_time(void)
2198 : {
2199 7945 : timekeeping_advance(TK_ADV_TICK);
2200 7945 : }
2201 :
2202 : /**
2203 : * getboottime64 - Return the real time of system boot.
2204 : * @ts: pointer to the timespec64 to be set
2205 : *
2206 : * Returns the wall-time of boot in a timespec64.
2207 : *
2208 : * This is based on the wall_to_monotonic offset and the total suspend
2209 : * time. Calls to settimeofday will affect the value returned (which
2210 : * basically means that however wrong your real time clock is at boot time,
2211 : * you get the right time here).
2212 : */
2213 0 : void getboottime64(struct timespec64 *ts)
2214 : {
2215 0 : struct timekeeper *tk = &tk_core.timekeeper;
2216 0 : ktime_t t = ktime_sub(tk->offs_real, tk->offs_boot);
2217 :
2218 0 : *ts = ktime_to_timespec64(t);
2219 0 : }
2220 : EXPORT_SYMBOL_GPL(getboottime64);
2221 :
2222 79951 : void ktime_get_coarse_real_ts64(struct timespec64 *ts)
2223 : {
2224 79951 : struct timekeeper *tk = &tk_core.timekeeper;
2225 79952 : unsigned int seq;
2226 :
2227 79952 : do {
2228 80745 : seq = read_seqcount_begin(&tk_core.seq);
2229 :
2230 79951 : *ts = tk_xtime(tk);
2231 79951 : } while (read_seqcount_retry(&tk_core.seq, seq));
2232 79950 : }
2233 : EXPORT_SYMBOL(ktime_get_coarse_real_ts64);
2234 :
2235 0 : void ktime_get_coarse_ts64(struct timespec64 *ts)
2236 : {
2237 0 : struct timekeeper *tk = &tk_core.timekeeper;
2238 0 : struct timespec64 now, mono;
2239 0 : unsigned int seq;
2240 :
2241 0 : do {
2242 0 : seq = read_seqcount_begin(&tk_core.seq);
2243 :
2244 0 : now = tk_xtime(tk);
2245 0 : mono = tk->wall_to_monotonic;
2246 0 : } while (read_seqcount_retry(&tk_core.seq, seq));
2247 :
2248 0 : set_normalized_timespec64(ts, now.tv_sec + mono.tv_sec,
2249 0 : now.tv_nsec + mono.tv_nsec);
2250 0 : }
2251 : EXPORT_SYMBOL(ktime_get_coarse_ts64);
2252 :
2253 : /*
2254 : * Must hold jiffies_lock
2255 : */
2256 24 : void do_timer(unsigned long ticks)
2257 : {
2258 24 : jiffies_64 += ticks;
2259 24 : calc_global_load();
2260 24 : }
2261 :
2262 : /**
2263 : * ktime_get_update_offsets_now - hrtimer helper
2264 : * @cwsseq: pointer to check and store the clock was set sequence number
2265 : * @offs_real: pointer to storage for monotonic -> realtime offset
2266 : * @offs_boot: pointer to storage for monotonic -> boottime offset
2267 : * @offs_tai: pointer to storage for monotonic -> clock tai offset
2268 : *
2269 : * Returns current monotonic time and updates the offsets if the
2270 : * sequence number in @cwsseq and timekeeper.clock_was_set_seq are
2271 : * different.
2272 : *
2273 : * Called from hrtimer_interrupt() or retrigger_next_event()
2274 : */
2275 28345 : ktime_t ktime_get_update_offsets_now(unsigned int *cwsseq, ktime_t *offs_real,
2276 : ktime_t *offs_boot, ktime_t *offs_tai)
2277 : {
2278 28345 : struct timekeeper *tk = &tk_core.timekeeper;
2279 28566 : unsigned int seq;
2280 28566 : ktime_t base;
2281 28566 : u64 nsecs;
2282 :
2283 28566 : do {
2284 299150 : seq = read_seqcount_begin(&tk_core.seq);
2285 :
2286 27943 : base = tk->tkr_mono.base;
2287 27943 : nsecs = timekeeping_get_ns(&tk->tkr_mono);
2288 28676 : base = ktime_add_ns(base, nsecs);
2289 :
2290 28676 : if (*cwsseq != tk->clock_was_set_seq) {
2291 8 : *cwsseq = tk->clock_was_set_seq;
2292 8 : *offs_real = tk->offs_real;
2293 8 : *offs_boot = tk->offs_boot;
2294 8 : *offs_tai = tk->offs_tai;
2295 : }
2296 :
2297 : /* Handle leapsecond insertion adjustments */
2298 28676 : if (unlikely(base >= tk->next_leap_ktime))
2299 0 : *offs_real = ktime_sub(tk->offs_real, ktime_set(1, 0));
2300 :
2301 28676 : } while (read_seqcount_retry(&tk_core.seq, seq));
2302 :
2303 28524 : return base;
2304 : }
2305 :
2306 : /*
2307 : * timekeeping_validate_timex - Ensures the timex is ok for use in do_adjtimex
2308 : */
2309 0 : static int timekeeping_validate_timex(const struct __kernel_timex *txc)
2310 : {
2311 0 : if (txc->modes & ADJ_ADJTIME) {
2312 : /* singleshot must not be used with any other mode bits */
2313 0 : if (!(txc->modes & ADJ_OFFSET_SINGLESHOT))
2314 : return -EINVAL;
2315 0 : if (!(txc->modes & ADJ_OFFSET_READONLY) &&
2316 0 : !capable(CAP_SYS_TIME))
2317 : return -EPERM;
2318 : } else {
2319 : /* In order to modify anything, you gotta be super-user! */
2320 0 : if (txc->modes && !capable(CAP_SYS_TIME))
2321 : return -EPERM;
2322 : /*
2323 : * if the quartz is off by more than 10% then
2324 : * something is VERY wrong!
2325 : */
2326 0 : if (txc->modes & ADJ_TICK &&
2327 0 : (txc->tick < 900000/USER_HZ ||
2328 : txc->tick > 1100000/USER_HZ))
2329 : return -EINVAL;
2330 : }
2331 :
2332 0 : if (txc->modes & ADJ_SETOFFSET) {
2333 : /* In order to inject time, you gotta be super-user! */
2334 0 : if (!capable(CAP_SYS_TIME))
2335 : return -EPERM;
2336 :
2337 : /*
2338 : * Validate if a timespec/timeval used to inject a time
2339 : * offset is valid. Offsets can be postive or negative, so
2340 : * we don't check tv_sec. The value of the timeval/timespec
2341 : * is the sum of its fields,but *NOTE*:
2342 : * The field tv_usec/tv_nsec must always be non-negative and
2343 : * we can't have more nanoseconds/microseconds than a second.
2344 : */
2345 0 : if (txc->time.tv_usec < 0)
2346 : return -EINVAL;
2347 :
2348 0 : if (txc->modes & ADJ_NANO) {
2349 0 : if (txc->time.tv_usec >= NSEC_PER_SEC)
2350 : return -EINVAL;
2351 : } else {
2352 0 : if (txc->time.tv_usec >= USEC_PER_SEC)
2353 : return -EINVAL;
2354 : }
2355 : }
2356 :
2357 : /*
2358 : * Check for potential multiplication overflows that can
2359 : * only happen on 64-bit systems:
2360 : */
2361 0 : if ((txc->modes & ADJ_FREQUENCY) && (BITS_PER_LONG == 64)) {
2362 0 : if (LLONG_MIN / PPM_SCALE > txc->freq)
2363 : return -EINVAL;
2364 0 : if (LLONG_MAX / PPM_SCALE < txc->freq)
2365 0 : return -EINVAL;
2366 : }
2367 :
2368 : return 0;
2369 : }
2370 :
2371 :
2372 : /**
2373 : * do_adjtimex() - Accessor function to NTP __do_adjtimex function
2374 : */
2375 0 : int do_adjtimex(struct __kernel_timex *txc)
2376 : {
2377 0 : struct timekeeper *tk = &tk_core.timekeeper;
2378 0 : struct audit_ntp_data ad;
2379 0 : unsigned long flags;
2380 0 : struct timespec64 ts;
2381 0 : s32 orig_tai, tai;
2382 0 : int ret;
2383 :
2384 : /* Validate the data before disabling interrupts */
2385 0 : ret = timekeeping_validate_timex(txc);
2386 0 : if (ret)
2387 : return ret;
2388 :
2389 0 : if (txc->modes & ADJ_SETOFFSET) {
2390 0 : struct timespec64 delta;
2391 0 : delta.tv_sec = txc->time.tv_sec;
2392 0 : delta.tv_nsec = txc->time.tv_usec;
2393 0 : if (!(txc->modes & ADJ_NANO))
2394 0 : delta.tv_nsec *= 1000;
2395 0 : ret = timekeeping_inject_offset(&delta);
2396 0 : if (ret)
2397 0 : return ret;
2398 :
2399 0 : audit_tk_injoffset(delta);
2400 : }
2401 :
2402 0 : audit_ntp_init(&ad);
2403 :
2404 0 : ktime_get_real_ts64(&ts);
2405 :
2406 0 : raw_spin_lock_irqsave(&timekeeper_lock, flags);
2407 0 : write_seqcount_begin(&tk_core.seq);
2408 :
2409 0 : orig_tai = tai = tk->tai_offset;
2410 0 : ret = __do_adjtimex(txc, &ts, &tai, &ad);
2411 :
2412 0 : if (tai != orig_tai) {
2413 0 : __timekeeping_set_tai_offset(tk, tai);
2414 0 : timekeeping_update(tk, TK_MIRROR | TK_CLOCK_WAS_SET);
2415 : }
2416 0 : tk_update_leap_state(tk);
2417 :
2418 0 : write_seqcount_end(&tk_core.seq);
2419 0 : raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
2420 :
2421 0 : audit_ntp_log(&ad);
2422 :
2423 : /* Update the multiplier immediately if frequency was set directly */
2424 0 : if (txc->modes & (ADJ_FREQUENCY | ADJ_TICK))
2425 0 : timekeeping_advance(TK_ADV_FREQ);
2426 :
2427 0 : if (tai != orig_tai)
2428 0 : clock_was_set();
2429 :
2430 0 : ntp_notify_cmos_timer();
2431 :
2432 0 : return ret;
2433 : }
2434 :
2435 : #ifdef CONFIG_NTP_PPS
2436 : /**
2437 : * hardpps() - Accessor function to NTP __hardpps function
2438 : */
2439 : void hardpps(const struct timespec64 *phase_ts, const struct timespec64 *raw_ts)
2440 : {
2441 : unsigned long flags;
2442 :
2443 : raw_spin_lock_irqsave(&timekeeper_lock, flags);
2444 : write_seqcount_begin(&tk_core.seq);
2445 :
2446 : __hardpps(phase_ts, raw_ts);
2447 :
2448 : write_seqcount_end(&tk_core.seq);
2449 : raw_spin_unlock_irqrestore(&timekeeper_lock, flags);
2450 : }
2451 : EXPORT_SYMBOL(hardpps);
2452 : #endif /* CONFIG_NTP_PPS */
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