Line data Source code
1 : // SPDX-License-Identifier: GPL-2.0-only
2 : /*
3 : * linux/kernel/reboot.c
4 : *
5 : * Copyright (C) 2013 Linus Torvalds
6 : */
7 :
8 : #define pr_fmt(fmt) "reboot: " fmt
9 :
10 : #include <linux/ctype.h>
11 : #include <linux/export.h>
12 : #include <linux/kexec.h>
13 : #include <linux/kmod.h>
14 : #include <linux/kmsg_dump.h>
15 : #include <linux/reboot.h>
16 : #include <linux/suspend.h>
17 : #include <linux/syscalls.h>
18 : #include <linux/syscore_ops.h>
19 : #include <linux/uaccess.h>
20 :
21 : /*
22 : * this indicates whether you can reboot with ctrl-alt-del: the default is yes
23 : */
24 :
25 : int C_A_D = 1;
26 : struct pid *cad_pid;
27 : EXPORT_SYMBOL(cad_pid);
28 :
29 : #if defined(CONFIG_ARM)
30 : #define DEFAULT_REBOOT_MODE = REBOOT_HARD
31 : #else
32 : #define DEFAULT_REBOOT_MODE
33 : #endif
34 : enum reboot_mode reboot_mode DEFAULT_REBOOT_MODE;
35 : enum reboot_mode panic_reboot_mode = REBOOT_UNDEFINED;
36 :
37 : /*
38 : * This variable is used privately to keep track of whether or not
39 : * reboot_type is still set to its default value (i.e., reboot= hasn't
40 : * been set on the command line). This is needed so that we can
41 : * suppress DMI scanning for reboot quirks. Without it, it's
42 : * impossible to override a faulty reboot quirk without recompiling.
43 : */
44 : int reboot_default = 1;
45 : int reboot_cpu;
46 : enum reboot_type reboot_type = BOOT_ACPI;
47 : int reboot_force;
48 :
49 : /*
50 : * If set, this is used for preparing the system to power off.
51 : */
52 :
53 : void (*pm_power_off_prepare)(void);
54 : EXPORT_SYMBOL_GPL(pm_power_off_prepare);
55 :
56 : /**
57 : * emergency_restart - reboot the system
58 : *
59 : * Without shutting down any hardware or taking any locks
60 : * reboot the system. This is called when we know we are in
61 : * trouble so this is our best effort to reboot. This is
62 : * safe to call in interrupt context.
63 : */
64 0 : void emergency_restart(void)
65 : {
66 0 : kmsg_dump(KMSG_DUMP_EMERG);
67 0 : machine_emergency_restart();
68 0 : }
69 : EXPORT_SYMBOL_GPL(emergency_restart);
70 :
71 0 : void kernel_restart_prepare(char *cmd)
72 : {
73 0 : blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd);
74 0 : system_state = SYSTEM_RESTART;
75 0 : usermodehelper_disable();
76 0 : device_shutdown();
77 0 : }
78 :
79 : /**
80 : * register_reboot_notifier - Register function to be called at reboot time
81 : * @nb: Info about notifier function to be called
82 : *
83 : * Registers a function with the list of functions
84 : * to be called at reboot time.
85 : *
86 : * Currently always returns zero, as blocking_notifier_chain_register()
87 : * always returns zero.
88 : */
89 2 : int register_reboot_notifier(struct notifier_block *nb)
90 : {
91 2 : return blocking_notifier_chain_register(&reboot_notifier_list, nb);
92 : }
93 : EXPORT_SYMBOL(register_reboot_notifier);
94 :
95 : /**
96 : * unregister_reboot_notifier - Unregister previously registered reboot notifier
97 : * @nb: Hook to be unregistered
98 : *
99 : * Unregisters a previously registered reboot
100 : * notifier function.
101 : *
102 : * Returns zero on success, or %-ENOENT on failure.
103 : */
104 0 : int unregister_reboot_notifier(struct notifier_block *nb)
105 : {
106 0 : return blocking_notifier_chain_unregister(&reboot_notifier_list, nb);
107 : }
108 : EXPORT_SYMBOL(unregister_reboot_notifier);
109 :
110 0 : static void devm_unregister_reboot_notifier(struct device *dev, void *res)
111 : {
112 0 : WARN_ON(unregister_reboot_notifier(*(struct notifier_block **)res));
113 0 : }
114 :
115 0 : int devm_register_reboot_notifier(struct device *dev, struct notifier_block *nb)
116 : {
117 0 : struct notifier_block **rcnb;
118 0 : int ret;
119 :
120 0 : rcnb = devres_alloc(devm_unregister_reboot_notifier,
121 : sizeof(*rcnb), GFP_KERNEL);
122 0 : if (!rcnb)
123 : return -ENOMEM;
124 :
125 0 : ret = register_reboot_notifier(nb);
126 0 : if (!ret) {
127 0 : *rcnb = nb;
128 0 : devres_add(dev, rcnb);
129 : } else {
130 0 : devres_free(rcnb);
131 : }
132 :
133 : return ret;
134 : }
135 : EXPORT_SYMBOL(devm_register_reboot_notifier);
136 :
137 : /*
138 : * Notifier list for kernel code which wants to be called
139 : * to restart the system.
140 : */
141 : static ATOMIC_NOTIFIER_HEAD(restart_handler_list);
142 :
143 : /**
144 : * register_restart_handler - Register function to be called to reset
145 : * the system
146 : * @nb: Info about handler function to be called
147 : * @nb->priority: Handler priority. Handlers should follow the
148 : * following guidelines for setting priorities.
149 : * 0: Restart handler of last resort,
150 : * with limited restart capabilities
151 : * 128: Default restart handler; use if no other
152 : * restart handler is expected to be available,
153 : * and/or if restart functionality is
154 : * sufficient to restart the entire system
155 : * 255: Highest priority restart handler, will
156 : * preempt all other restart handlers
157 : *
158 : * Registers a function with code to be called to restart the
159 : * system.
160 : *
161 : * Registered functions will be called from machine_restart as last
162 : * step of the restart sequence (if the architecture specific
163 : * machine_restart function calls do_kernel_restart - see below
164 : * for details).
165 : * Registered functions are expected to restart the system immediately.
166 : * If more than one function is registered, the restart handler priority
167 : * selects which function will be called first.
168 : *
169 : * Restart handlers are expected to be registered from non-architecture
170 : * code, typically from drivers. A typical use case would be a system
171 : * where restart functionality is provided through a watchdog. Multiple
172 : * restart handlers may exist; for example, one restart handler might
173 : * restart the entire system, while another only restarts the CPU.
174 : * In such cases, the restart handler which only restarts part of the
175 : * hardware is expected to register with low priority to ensure that
176 : * it only runs if no other means to restart the system is available.
177 : *
178 : * Currently always returns zero, as atomic_notifier_chain_register()
179 : * always returns zero.
180 : */
181 0 : int register_restart_handler(struct notifier_block *nb)
182 : {
183 0 : return atomic_notifier_chain_register(&restart_handler_list, nb);
184 : }
185 : EXPORT_SYMBOL(register_restart_handler);
186 :
187 : /**
188 : * unregister_restart_handler - Unregister previously registered
189 : * restart handler
190 : * @nb: Hook to be unregistered
191 : *
192 : * Unregisters a previously registered restart handler function.
193 : *
194 : * Returns zero on success, or %-ENOENT on failure.
195 : */
196 0 : int unregister_restart_handler(struct notifier_block *nb)
197 : {
198 0 : return atomic_notifier_chain_unregister(&restart_handler_list, nb);
199 : }
200 : EXPORT_SYMBOL(unregister_restart_handler);
201 :
202 : /**
203 : * do_kernel_restart - Execute kernel restart handler call chain
204 : *
205 : * Calls functions registered with register_restart_handler.
206 : *
207 : * Expected to be called from machine_restart as last step of the restart
208 : * sequence.
209 : *
210 : * Restarts the system immediately if a restart handler function has been
211 : * registered. Otherwise does nothing.
212 : */
213 0 : void do_kernel_restart(char *cmd)
214 : {
215 0 : atomic_notifier_call_chain(&restart_handler_list, reboot_mode, cmd);
216 0 : }
217 :
218 0 : void migrate_to_reboot_cpu(void)
219 : {
220 : /* The boot cpu is always logical cpu 0 */
221 0 : int cpu = reboot_cpu;
222 :
223 0 : cpu_hotplug_disable();
224 :
225 : /* Make certain the cpu I'm about to reboot on is online */
226 0 : if (!cpu_online(cpu))
227 0 : cpu = cpumask_first(cpu_online_mask);
228 :
229 : /* Prevent races with other tasks migrating this task */
230 0 : current->flags |= PF_NO_SETAFFINITY;
231 :
232 : /* Make certain I only run on the appropriate processor */
233 0 : set_cpus_allowed_ptr(current, cpumask_of(cpu));
234 0 : }
235 :
236 : /**
237 : * kernel_restart - reboot the system
238 : * @cmd: pointer to buffer containing command to execute for restart
239 : * or %NULL
240 : *
241 : * Shutdown everything and perform a clean reboot.
242 : * This is not safe to call in interrupt context.
243 : */
244 0 : void kernel_restart(char *cmd)
245 : {
246 0 : kernel_restart_prepare(cmd);
247 0 : if (pm_power_off_prepare)
248 0 : pm_power_off_prepare();
249 0 : migrate_to_reboot_cpu();
250 0 : syscore_shutdown();
251 0 : if (!cmd)
252 0 : pr_emerg("Restarting system\n");
253 : else
254 0 : pr_emerg("Restarting system with command '%s'\n", cmd);
255 0 : kmsg_dump(KMSG_DUMP_SHUTDOWN);
256 0 : machine_restart(cmd);
257 0 : }
258 : EXPORT_SYMBOL_GPL(kernel_restart);
259 :
260 0 : static void kernel_shutdown_prepare(enum system_states state)
261 : {
262 0 : blocking_notifier_call_chain(&reboot_notifier_list,
263 : (state == SYSTEM_HALT) ? SYS_HALT : SYS_POWER_OFF, NULL);
264 0 : system_state = state;
265 0 : usermodehelper_disable();
266 0 : device_shutdown();
267 0 : }
268 : /**
269 : * kernel_halt - halt the system
270 : *
271 : * Shutdown everything and perform a clean system halt.
272 : */
273 0 : void kernel_halt(void)
274 : {
275 0 : kernel_shutdown_prepare(SYSTEM_HALT);
276 0 : migrate_to_reboot_cpu();
277 0 : syscore_shutdown();
278 0 : pr_emerg("System halted\n");
279 0 : kmsg_dump(KMSG_DUMP_SHUTDOWN);
280 0 : machine_halt();
281 0 : }
282 : EXPORT_SYMBOL_GPL(kernel_halt);
283 :
284 : /**
285 : * kernel_power_off - power_off the system
286 : *
287 : * Shutdown everything and perform a clean system power_off.
288 : */
289 0 : void kernel_power_off(void)
290 : {
291 0 : kernel_shutdown_prepare(SYSTEM_POWER_OFF);
292 0 : if (pm_power_off_prepare)
293 0 : pm_power_off_prepare();
294 0 : migrate_to_reboot_cpu();
295 0 : syscore_shutdown();
296 0 : pr_emerg("Power down\n");
297 0 : kmsg_dump(KMSG_DUMP_SHUTDOWN);
298 0 : machine_power_off();
299 0 : }
300 : EXPORT_SYMBOL_GPL(kernel_power_off);
301 :
302 : DEFINE_MUTEX(system_transition_mutex);
303 :
304 : /*
305 : * Reboot system call: for obvious reasons only root may call it,
306 : * and even root needs to set up some magic numbers in the registers
307 : * so that some mistake won't make this reboot the whole machine.
308 : * You can also set the meaning of the ctrl-alt-del-key here.
309 : *
310 : * reboot doesn't sync: do that yourself before calling this.
311 : */
312 2 : SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd,
313 : void __user *, arg)
314 : {
315 1 : struct pid_namespace *pid_ns = task_active_pid_ns(current);
316 1 : char buffer[256];
317 1 : int ret = 0;
318 :
319 : /* We only trust the superuser with rebooting the system. */
320 1 : if (!ns_capable(pid_ns->user_ns, CAP_SYS_BOOT))
321 : return -EPERM;
322 :
323 : /* For safety, we require "magic" arguments. */
324 1 : if (magic1 != LINUX_REBOOT_MAGIC1 ||
325 1 : (magic2 != LINUX_REBOOT_MAGIC2 &&
326 1 : magic2 != LINUX_REBOOT_MAGIC2A &&
327 0 : magic2 != LINUX_REBOOT_MAGIC2B &&
328 0 : magic2 != LINUX_REBOOT_MAGIC2C))
329 : return -EINVAL;
330 :
331 : /*
332 : * If pid namespaces are enabled and the current task is in a child
333 : * pid_namespace, the command is handled by reboot_pid_ns() which will
334 : * call do_exit().
335 : */
336 1 : ret = reboot_pid_ns(pid_ns, cmd);
337 1 : if (ret)
338 : return ret;
339 :
340 : /* Instead of trying to make the power_off code look like
341 : * halt when pm_power_off is not set do it the easy way.
342 : */
343 1 : if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off)
344 0 : cmd = LINUX_REBOOT_CMD_HALT;
345 :
346 1 : mutex_lock(&system_transition_mutex);
347 1 : switch (cmd) {
348 0 : case LINUX_REBOOT_CMD_RESTART:
349 0 : kernel_restart(NULL);
350 0 : break;
351 :
352 0 : case LINUX_REBOOT_CMD_CAD_ON:
353 0 : C_A_D = 1;
354 0 : break;
355 :
356 1 : case LINUX_REBOOT_CMD_CAD_OFF:
357 1 : C_A_D = 0;
358 1 : break;
359 :
360 0 : case LINUX_REBOOT_CMD_HALT:
361 0 : kernel_halt();
362 0 : do_exit(0);
363 : panic("cannot halt");
364 :
365 0 : case LINUX_REBOOT_CMD_POWER_OFF:
366 0 : kernel_power_off();
367 0 : do_exit(0);
368 0 : break;
369 :
370 0 : case LINUX_REBOOT_CMD_RESTART2:
371 0 : ret = strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1);
372 0 : if (ret < 0) {
373 : ret = -EFAULT;
374 : break;
375 : }
376 0 : buffer[sizeof(buffer) - 1] = '\0';
377 :
378 0 : kernel_restart(buffer);
379 0 : break;
380 :
381 : #ifdef CONFIG_KEXEC_CORE
382 : case LINUX_REBOOT_CMD_KEXEC:
383 : ret = kernel_kexec();
384 : break;
385 : #endif
386 :
387 : #ifdef CONFIG_HIBERNATION
388 : case LINUX_REBOOT_CMD_SW_SUSPEND:
389 : ret = hibernate();
390 : break;
391 : #endif
392 :
393 : default:
394 : ret = -EINVAL;
395 : break;
396 : }
397 1 : mutex_unlock(&system_transition_mutex);
398 1 : return ret;
399 : }
400 :
401 0 : static void deferred_cad(struct work_struct *dummy)
402 : {
403 0 : kernel_restart(NULL);
404 0 : }
405 :
406 : /*
407 : * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
408 : * As it's called within an interrupt, it may NOT sync: the only choice
409 : * is whether to reboot at once, or just ignore the ctrl-alt-del.
410 : */
411 0 : void ctrl_alt_del(void)
412 : {
413 0 : static DECLARE_WORK(cad_work, deferred_cad);
414 :
415 0 : if (C_A_D)
416 0 : schedule_work(&cad_work);
417 : else
418 0 : kill_cad_pid(SIGINT, 1);
419 0 : }
420 :
421 : char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";
422 : static const char reboot_cmd[] = "/sbin/reboot";
423 :
424 0 : static int run_cmd(const char *cmd)
425 : {
426 0 : char **argv;
427 0 : static char *envp[] = {
428 : "HOME=/",
429 : "PATH=/sbin:/bin:/usr/sbin:/usr/bin",
430 : NULL
431 : };
432 0 : int ret;
433 0 : argv = argv_split(GFP_KERNEL, cmd, NULL);
434 0 : if (argv) {
435 0 : ret = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_EXEC);
436 0 : argv_free(argv);
437 : } else {
438 : ret = -ENOMEM;
439 : }
440 :
441 0 : return ret;
442 : }
443 :
444 0 : static int __orderly_reboot(void)
445 : {
446 0 : int ret;
447 :
448 0 : ret = run_cmd(reboot_cmd);
449 :
450 0 : if (ret) {
451 0 : pr_warn("Failed to start orderly reboot: forcing the issue\n");
452 0 : emergency_sync();
453 0 : kernel_restart(NULL);
454 : }
455 :
456 0 : return ret;
457 : }
458 :
459 0 : static int __orderly_poweroff(bool force)
460 : {
461 0 : int ret;
462 :
463 0 : ret = run_cmd(poweroff_cmd);
464 :
465 0 : if (ret && force) {
466 0 : pr_warn("Failed to start orderly shutdown: forcing the issue\n");
467 :
468 : /*
469 : * I guess this should try to kick off some daemon to sync and
470 : * poweroff asap. Or not even bother syncing if we're doing an
471 : * emergency shutdown?
472 : */
473 0 : emergency_sync();
474 0 : kernel_power_off();
475 : }
476 :
477 0 : return ret;
478 : }
479 :
480 : static bool poweroff_force;
481 :
482 0 : static void poweroff_work_func(struct work_struct *work)
483 : {
484 0 : __orderly_poweroff(poweroff_force);
485 0 : }
486 :
487 : static DECLARE_WORK(poweroff_work, poweroff_work_func);
488 :
489 : /**
490 : * orderly_poweroff - Trigger an orderly system poweroff
491 : * @force: force poweroff if command execution fails
492 : *
493 : * This may be called from any context to trigger a system shutdown.
494 : * If the orderly shutdown fails, it will force an immediate shutdown.
495 : */
496 0 : void orderly_poweroff(bool force)
497 : {
498 0 : if (force) /* do not override the pending "true" */
499 0 : poweroff_force = true;
500 0 : schedule_work(&poweroff_work);
501 0 : }
502 : EXPORT_SYMBOL_GPL(orderly_poweroff);
503 :
504 0 : static void reboot_work_func(struct work_struct *work)
505 : {
506 0 : __orderly_reboot();
507 0 : }
508 :
509 : static DECLARE_WORK(reboot_work, reboot_work_func);
510 :
511 : /**
512 : * orderly_reboot - Trigger an orderly system reboot
513 : *
514 : * This may be called from any context to trigger a system reboot.
515 : * If the orderly reboot fails, it will force an immediate reboot.
516 : */
517 0 : void orderly_reboot(void)
518 : {
519 0 : schedule_work(&reboot_work);
520 0 : }
521 : EXPORT_SYMBOL_GPL(orderly_reboot);
522 :
523 1 : static int __init reboot_setup(char *str)
524 : {
525 1 : for (;;) {
526 1 : enum reboot_mode *mode;
527 :
528 : /*
529 : * Having anything passed on the command line via
530 : * reboot= will cause us to disable DMI checking
531 : * below.
532 : */
533 1 : reboot_default = 0;
534 :
535 1 : if (!strncmp(str, "panic_", 6)) {
536 0 : mode = &panic_reboot_mode;
537 0 : str += 6;
538 : } else {
539 : mode = &reboot_mode;
540 : }
541 :
542 1 : switch (*str) {
543 0 : case 'w':
544 0 : *mode = REBOOT_WARM;
545 0 : break;
546 :
547 0 : case 'c':
548 0 : *mode = REBOOT_COLD;
549 0 : break;
550 :
551 0 : case 'h':
552 0 : *mode = REBOOT_HARD;
553 0 : break;
554 :
555 0 : case 's':
556 : /*
557 : * reboot_cpu is s[mp]#### with #### being the processor
558 : * to be used for rebooting. Skip 's' or 'smp' prefix.
559 : */
560 0 : str += str[1] == 'm' && str[2] == 'p' ? 3 : 1;
561 :
562 0 : if (isdigit(str[0])) {
563 0 : int cpu = simple_strtoul(str, NULL, 0);
564 :
565 0 : if (cpu >= num_possible_cpus()) {
566 0 : pr_err("Ignoring the CPU number in reboot= option. "
567 : "CPU %d exceeds possible cpu number %d\n",
568 : cpu, num_possible_cpus());
569 0 : break;
570 : }
571 0 : reboot_cpu = cpu;
572 : } else
573 0 : *mode = REBOOT_SOFT;
574 : break;
575 :
576 0 : case 'g':
577 0 : *mode = REBOOT_GPIO;
578 0 : break;
579 :
580 1 : case 'b':
581 : case 'a':
582 : case 'k':
583 : case 't':
584 : case 'e':
585 : case 'p':
586 1 : reboot_type = *str;
587 1 : break;
588 :
589 0 : case 'f':
590 0 : reboot_force = 1;
591 0 : break;
592 : }
593 :
594 1 : str = strchr(str, ',');
595 1 : if (str)
596 0 : str++;
597 : else
598 : break;
599 : }
600 1 : return 1;
601 : }
602 : __setup("reboot=", reboot_setup);
603 :
604 : #ifdef CONFIG_SYSFS
605 :
606 : #define REBOOT_COLD_STR "cold"
607 : #define REBOOT_WARM_STR "warm"
608 : #define REBOOT_HARD_STR "hard"
609 : #define REBOOT_SOFT_STR "soft"
610 : #define REBOOT_GPIO_STR "gpio"
611 : #define REBOOT_UNDEFINED_STR "undefined"
612 :
613 : #define BOOT_TRIPLE_STR "triple"
614 : #define BOOT_KBD_STR "kbd"
615 : #define BOOT_BIOS_STR "bios"
616 : #define BOOT_ACPI_STR "acpi"
617 : #define BOOT_EFI_STR "efi"
618 : #define BOOT_PCI_STR "pci"
619 :
620 0 : static ssize_t mode_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
621 : {
622 0 : const char *val;
623 :
624 0 : switch (reboot_mode) {
625 : case REBOOT_COLD:
626 : val = REBOOT_COLD_STR;
627 : break;
628 : case REBOOT_WARM:
629 : val = REBOOT_WARM_STR;
630 : break;
631 : case REBOOT_HARD:
632 : val = REBOOT_HARD_STR;
633 : break;
634 : case REBOOT_SOFT:
635 : val = REBOOT_SOFT_STR;
636 : break;
637 : case REBOOT_GPIO:
638 : val = REBOOT_GPIO_STR;
639 : break;
640 : default:
641 : val = REBOOT_UNDEFINED_STR;
642 : }
643 :
644 0 : return sprintf(buf, "%s\n", val);
645 : }
646 0 : static ssize_t mode_store(struct kobject *kobj, struct kobj_attribute *attr,
647 : const char *buf, size_t count)
648 : {
649 0 : if (!capable(CAP_SYS_BOOT))
650 : return -EPERM;
651 :
652 0 : if (!strncmp(buf, REBOOT_COLD_STR, strlen(REBOOT_COLD_STR)))
653 0 : reboot_mode = REBOOT_COLD;
654 0 : else if (!strncmp(buf, REBOOT_WARM_STR, strlen(REBOOT_WARM_STR)))
655 0 : reboot_mode = REBOOT_WARM;
656 0 : else if (!strncmp(buf, REBOOT_HARD_STR, strlen(REBOOT_HARD_STR)))
657 0 : reboot_mode = REBOOT_HARD;
658 0 : else if (!strncmp(buf, REBOOT_SOFT_STR, strlen(REBOOT_SOFT_STR)))
659 0 : reboot_mode = REBOOT_SOFT;
660 0 : else if (!strncmp(buf, REBOOT_GPIO_STR, strlen(REBOOT_GPIO_STR)))
661 0 : reboot_mode = REBOOT_GPIO;
662 : else
663 : return -EINVAL;
664 :
665 0 : reboot_default = 0;
666 :
667 0 : return count;
668 : }
669 : static struct kobj_attribute reboot_mode_attr = __ATTR_RW(mode);
670 :
671 : #ifdef CONFIG_X86
672 0 : static ssize_t force_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
673 : {
674 0 : return sprintf(buf, "%d\n", reboot_force);
675 : }
676 0 : static ssize_t force_store(struct kobject *kobj, struct kobj_attribute *attr,
677 : const char *buf, size_t count)
678 : {
679 0 : bool res;
680 :
681 0 : if (!capable(CAP_SYS_BOOT))
682 : return -EPERM;
683 :
684 0 : if (kstrtobool(buf, &res))
685 : return -EINVAL;
686 :
687 0 : reboot_default = 0;
688 0 : reboot_force = res;
689 :
690 0 : return count;
691 : }
692 : static struct kobj_attribute reboot_force_attr = __ATTR_RW(force);
693 :
694 0 : static ssize_t type_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
695 : {
696 0 : const char *val;
697 :
698 0 : switch (reboot_type) {
699 : case BOOT_TRIPLE:
700 : val = BOOT_TRIPLE_STR;
701 : break;
702 : case BOOT_KBD:
703 : val = BOOT_KBD_STR;
704 : break;
705 : case BOOT_BIOS:
706 : val = BOOT_BIOS_STR;
707 : break;
708 : case BOOT_ACPI:
709 : val = BOOT_ACPI_STR;
710 : break;
711 : case BOOT_EFI:
712 : val = BOOT_EFI_STR;
713 : break;
714 : case BOOT_CF9_FORCE:
715 : val = BOOT_PCI_STR;
716 : break;
717 : default:
718 : val = REBOOT_UNDEFINED_STR;
719 : }
720 :
721 0 : return sprintf(buf, "%s\n", val);
722 : }
723 0 : static ssize_t type_store(struct kobject *kobj, struct kobj_attribute *attr,
724 : const char *buf, size_t count)
725 : {
726 0 : if (!capable(CAP_SYS_BOOT))
727 : return -EPERM;
728 :
729 0 : if (!strncmp(buf, BOOT_TRIPLE_STR, strlen(BOOT_TRIPLE_STR)))
730 0 : reboot_type = BOOT_TRIPLE;
731 0 : else if (!strncmp(buf, BOOT_KBD_STR, strlen(BOOT_KBD_STR)))
732 0 : reboot_type = BOOT_KBD;
733 0 : else if (!strncmp(buf, BOOT_BIOS_STR, strlen(BOOT_BIOS_STR)))
734 0 : reboot_type = BOOT_BIOS;
735 0 : else if (!strncmp(buf, BOOT_ACPI_STR, strlen(BOOT_ACPI_STR)))
736 0 : reboot_type = BOOT_ACPI;
737 0 : else if (!strncmp(buf, BOOT_EFI_STR, strlen(BOOT_EFI_STR)))
738 0 : reboot_type = BOOT_EFI;
739 0 : else if (!strncmp(buf, BOOT_PCI_STR, strlen(BOOT_PCI_STR)))
740 0 : reboot_type = BOOT_CF9_FORCE;
741 : else
742 : return -EINVAL;
743 :
744 0 : reboot_default = 0;
745 :
746 0 : return count;
747 : }
748 : static struct kobj_attribute reboot_type_attr = __ATTR_RW(type);
749 : #endif
750 :
751 : #ifdef CONFIG_SMP
752 0 : static ssize_t cpu_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
753 : {
754 0 : return sprintf(buf, "%d\n", reboot_cpu);
755 : }
756 0 : static ssize_t cpu_store(struct kobject *kobj, struct kobj_attribute *attr,
757 : const char *buf, size_t count)
758 : {
759 0 : unsigned int cpunum;
760 0 : int rc;
761 :
762 0 : if (!capable(CAP_SYS_BOOT))
763 : return -EPERM;
764 :
765 0 : rc = kstrtouint(buf, 0, &cpunum);
766 :
767 0 : if (rc)
768 0 : return rc;
769 :
770 0 : if (cpunum >= num_possible_cpus())
771 : return -ERANGE;
772 :
773 0 : reboot_default = 0;
774 0 : reboot_cpu = cpunum;
775 :
776 0 : return count;
777 : }
778 : static struct kobj_attribute reboot_cpu_attr = __ATTR_RW(cpu);
779 : #endif
780 :
781 : static struct attribute *reboot_attrs[] = {
782 : &reboot_mode_attr.attr,
783 : #ifdef CONFIG_X86
784 : &reboot_force_attr.attr,
785 : &reboot_type_attr.attr,
786 : #endif
787 : #ifdef CONFIG_SMP
788 : &reboot_cpu_attr.attr,
789 : #endif
790 : NULL,
791 : };
792 :
793 : static const struct attribute_group reboot_attr_group = {
794 : .attrs = reboot_attrs,
795 : };
796 :
797 1 : static int __init reboot_ksysfs_init(void)
798 : {
799 1 : struct kobject *reboot_kobj;
800 1 : int ret;
801 :
802 1 : reboot_kobj = kobject_create_and_add("reboot", kernel_kobj);
803 1 : if (!reboot_kobj)
804 : return -ENOMEM;
805 :
806 1 : ret = sysfs_create_group(reboot_kobj, &reboot_attr_group);
807 1 : if (ret) {
808 0 : kobject_put(reboot_kobj);
809 0 : return ret;
810 : }
811 :
812 : return 0;
813 : }
814 : late_initcall(reboot_ksysfs_init);
815 :
816 : #endif
|
