Commit | Line | Data |
---|---|---|
15d94b82 RH |
1 | /* |
2 | * linux/kernel/reboot.c | |
3 | * | |
4 | * Copyright (C) 2013 Linus Torvalds | |
5 | */ | |
6 | ||
972ee83d RH |
7 | #define pr_fmt(fmt) "reboot: " fmt |
8 | ||
1b3a5d02 | 9 | #include <linux/ctype.h> |
15d94b82 RH |
10 | #include <linux/export.h> |
11 | #include <linux/kexec.h> | |
12 | #include <linux/kmod.h> | |
13 | #include <linux/kmsg_dump.h> | |
14 | #include <linux/reboot.h> | |
15 | #include <linux/suspend.h> | |
16 | #include <linux/syscalls.h> | |
17 | #include <linux/syscore_ops.h> | |
18 | #include <linux/uaccess.h> | |
19 | ||
20 | /* | |
21 | * this indicates whether you can reboot with ctrl-alt-del: the default is yes | |
22 | */ | |
23 | ||
24 | int C_A_D = 1; | |
25 | struct pid *cad_pid; | |
26 | EXPORT_SYMBOL(cad_pid); | |
27 | ||
1b3a5d02 RH |
28 | #if defined(CONFIG_ARM) || defined(CONFIG_UNICORE32) |
29 | #define DEFAULT_REBOOT_MODE = REBOOT_HARD | |
30 | #else | |
31 | #define DEFAULT_REBOOT_MODE | |
32 | #endif | |
33 | enum reboot_mode reboot_mode DEFAULT_REBOOT_MODE; | |
34 | ||
e2f0b88e CL |
35 | /* |
36 | * This variable is used privately to keep track of whether or not | |
37 | * reboot_type is still set to its default value (i.e., reboot= hasn't | |
38 | * been set on the command line). This is needed so that we can | |
39 | * suppress DMI scanning for reboot quirks. Without it, it's | |
40 | * impossible to override a faulty reboot quirk without recompiling. | |
41 | */ | |
42 | int reboot_default = 1; | |
1b3a5d02 RH |
43 | int reboot_cpu; |
44 | enum reboot_type reboot_type = BOOT_ACPI; | |
45 | int reboot_force; | |
46 | ||
15d94b82 RH |
47 | /* |
48 | * If set, this is used for preparing the system to power off. | |
49 | */ | |
50 | ||
51 | void (*pm_power_off_prepare)(void); | |
74f008f2 | 52 | EXPORT_SYMBOL_GPL(pm_power_off_prepare); |
15d94b82 RH |
53 | |
54 | /** | |
55 | * emergency_restart - reboot the system | |
56 | * | |
57 | * Without shutting down any hardware or taking any locks | |
58 | * reboot the system. This is called when we know we are in | |
59 | * trouble so this is our best effort to reboot. This is | |
60 | * safe to call in interrupt context. | |
61 | */ | |
62 | void emergency_restart(void) | |
63 | { | |
64 | kmsg_dump(KMSG_DUMP_EMERG); | |
65 | machine_emergency_restart(); | |
66 | } | |
67 | EXPORT_SYMBOL_GPL(emergency_restart); | |
68 | ||
69 | void kernel_restart_prepare(char *cmd) | |
70 | { | |
71 | blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd); | |
72 | system_state = SYSTEM_RESTART; | |
73 | usermodehelper_disable(); | |
74 | device_shutdown(); | |
75 | } | |
76 | ||
77 | /** | |
78 | * register_reboot_notifier - Register function to be called at reboot time | |
79 | * @nb: Info about notifier function to be called | |
80 | * | |
81 | * Registers a function with the list of functions | |
82 | * to be called at reboot time. | |
83 | * | |
84 | * Currently always returns zero, as blocking_notifier_chain_register() | |
85 | * always returns zero. | |
86 | */ | |
87 | int register_reboot_notifier(struct notifier_block *nb) | |
88 | { | |
89 | return blocking_notifier_chain_register(&reboot_notifier_list, nb); | |
90 | } | |
91 | EXPORT_SYMBOL(register_reboot_notifier); | |
92 | ||
93 | /** | |
94 | * unregister_reboot_notifier - Unregister previously registered reboot notifier | |
95 | * @nb: Hook to be unregistered | |
96 | * | |
97 | * Unregisters a previously registered reboot | |
98 | * notifier function. | |
99 | * | |
100 | * Returns zero on success, or %-ENOENT on failure. | |
101 | */ | |
102 | int unregister_reboot_notifier(struct notifier_block *nb) | |
103 | { | |
104 | return blocking_notifier_chain_unregister(&reboot_notifier_list, nb); | |
105 | } | |
106 | EXPORT_SYMBOL(unregister_reboot_notifier); | |
107 | ||
2d8364ba AS |
108 | static void devm_unregister_reboot_notifier(struct device *dev, void *res) |
109 | { | |
110 | WARN_ON(unregister_reboot_notifier(*(struct notifier_block **)res)); | |
111 | } | |
112 | ||
113 | int devm_register_reboot_notifier(struct device *dev, struct notifier_block *nb) | |
114 | { | |
115 | struct notifier_block **rcnb; | |
116 | int ret; | |
117 | ||
118 | rcnb = devres_alloc(devm_unregister_reboot_notifier, | |
119 | sizeof(*rcnb), GFP_KERNEL); | |
120 | if (!rcnb) | |
121 | return -ENOMEM; | |
122 | ||
123 | ret = register_reboot_notifier(nb); | |
124 | if (!ret) { | |
125 | *rcnb = nb; | |
126 | devres_add(dev, rcnb); | |
127 | } else { | |
128 | devres_free(rcnb); | |
129 | } | |
130 | ||
131 | return ret; | |
132 | } | |
133 | EXPORT_SYMBOL(devm_register_reboot_notifier); | |
134 | ||
b63adb97 GR |
135 | /* |
136 | * Notifier list for kernel code which wants to be called | |
137 | * to restart the system. | |
138 | */ | |
139 | static ATOMIC_NOTIFIER_HEAD(restart_handler_list); | |
140 | ||
141 | /** | |
142 | * register_restart_handler - Register function to be called to reset | |
143 | * the system | |
144 | * @nb: Info about handler function to be called | |
145 | * @nb->priority: Handler priority. Handlers should follow the | |
146 | * following guidelines for setting priorities. | |
147 | * 0: Restart handler of last resort, | |
148 | * with limited restart capabilities | |
149 | * 128: Default restart handler; use if no other | |
150 | * restart handler is expected to be available, | |
151 | * and/or if restart functionality is | |
152 | * sufficient to restart the entire system | |
153 | * 255: Highest priority restart handler, will | |
154 | * preempt all other restart handlers | |
155 | * | |
156 | * Registers a function with code to be called to restart the | |
157 | * system. | |
158 | * | |
159 | * Registered functions will be called from machine_restart as last | |
160 | * step of the restart sequence (if the architecture specific | |
161 | * machine_restart function calls do_kernel_restart - see below | |
162 | * for details). | |
163 | * Registered functions are expected to restart the system immediately. | |
164 | * If more than one function is registered, the restart handler priority | |
165 | * selects which function will be called first. | |
166 | * | |
167 | * Restart handlers are expected to be registered from non-architecture | |
168 | * code, typically from drivers. A typical use case would be a system | |
169 | * where restart functionality is provided through a watchdog. Multiple | |
170 | * restart handlers may exist; for example, one restart handler might | |
171 | * restart the entire system, while another only restarts the CPU. | |
172 | * In such cases, the restart handler which only restarts part of the | |
173 | * hardware is expected to register with low priority to ensure that | |
174 | * it only runs if no other means to restart the system is available. | |
175 | * | |
176 | * Currently always returns zero, as atomic_notifier_chain_register() | |
177 | * always returns zero. | |
178 | */ | |
179 | int register_restart_handler(struct notifier_block *nb) | |
180 | { | |
181 | return atomic_notifier_chain_register(&restart_handler_list, nb); | |
182 | } | |
183 | EXPORT_SYMBOL(register_restart_handler); | |
184 | ||
185 | /** | |
186 | * unregister_restart_handler - Unregister previously registered | |
187 | * restart handler | |
188 | * @nb: Hook to be unregistered | |
189 | * | |
190 | * Unregisters a previously registered restart handler function. | |
191 | * | |
192 | * Returns zero on success, or %-ENOENT on failure. | |
193 | */ | |
194 | int unregister_restart_handler(struct notifier_block *nb) | |
195 | { | |
196 | return atomic_notifier_chain_unregister(&restart_handler_list, nb); | |
197 | } | |
198 | EXPORT_SYMBOL(unregister_restart_handler); | |
199 | ||
200 | /** | |
201 | * do_kernel_restart - Execute kernel restart handler call chain | |
202 | * | |
203 | * Calls functions registered with register_restart_handler. | |
204 | * | |
205 | * Expected to be called from machine_restart as last step of the restart | |
206 | * sequence. | |
207 | * | |
208 | * Restarts the system immediately if a restart handler function has been | |
209 | * registered. Otherwise does nothing. | |
210 | */ | |
211 | void do_kernel_restart(char *cmd) | |
212 | { | |
213 | atomic_notifier_call_chain(&restart_handler_list, reboot_mode, cmd); | |
214 | } | |
215 | ||
c97102ba | 216 | void migrate_to_reboot_cpu(void) |
15d94b82 RH |
217 | { |
218 | /* The boot cpu is always logical cpu 0 */ | |
1b3a5d02 | 219 | int cpu = reboot_cpu; |
15d94b82 RH |
220 | |
221 | cpu_hotplug_disable(); | |
222 | ||
223 | /* Make certain the cpu I'm about to reboot on is online */ | |
224 | if (!cpu_online(cpu)) | |
225 | cpu = cpumask_first(cpu_online_mask); | |
226 | ||
227 | /* Prevent races with other tasks migrating this task */ | |
228 | current->flags |= PF_NO_SETAFFINITY; | |
229 | ||
230 | /* Make certain I only run on the appropriate processor */ | |
231 | set_cpus_allowed_ptr(current, cpumask_of(cpu)); | |
232 | } | |
233 | ||
234 | /** | |
235 | * kernel_restart - reboot the system | |
236 | * @cmd: pointer to buffer containing command to execute for restart | |
237 | * or %NULL | |
238 | * | |
239 | * Shutdown everything and perform a clean reboot. | |
240 | * This is not safe to call in interrupt context. | |
241 | */ | |
242 | void kernel_restart(char *cmd) | |
243 | { | |
244 | kernel_restart_prepare(cmd); | |
245 | migrate_to_reboot_cpu(); | |
246 | syscore_shutdown(); | |
247 | if (!cmd) | |
972ee83d | 248 | pr_emerg("Restarting system\n"); |
15d94b82 | 249 | else |
972ee83d | 250 | pr_emerg("Restarting system with command '%s'\n", cmd); |
15d94b82 RH |
251 | kmsg_dump(KMSG_DUMP_RESTART); |
252 | machine_restart(cmd); | |
253 | } | |
254 | EXPORT_SYMBOL_GPL(kernel_restart); | |
255 | ||
256 | static void kernel_shutdown_prepare(enum system_states state) | |
257 | { | |
258 | blocking_notifier_call_chain(&reboot_notifier_list, | |
972ee83d | 259 | (state == SYSTEM_HALT) ? SYS_HALT : SYS_POWER_OFF, NULL); |
15d94b82 RH |
260 | system_state = state; |
261 | usermodehelper_disable(); | |
262 | device_shutdown(); | |
263 | } | |
264 | /** | |
265 | * kernel_halt - halt the system | |
266 | * | |
267 | * Shutdown everything and perform a clean system halt. | |
268 | */ | |
269 | void kernel_halt(void) | |
270 | { | |
271 | kernel_shutdown_prepare(SYSTEM_HALT); | |
272 | migrate_to_reboot_cpu(); | |
273 | syscore_shutdown(); | |
972ee83d | 274 | pr_emerg("System halted\n"); |
15d94b82 RH |
275 | kmsg_dump(KMSG_DUMP_HALT); |
276 | machine_halt(); | |
277 | } | |
15d94b82 RH |
278 | EXPORT_SYMBOL_GPL(kernel_halt); |
279 | ||
280 | /** | |
281 | * kernel_power_off - power_off the system | |
282 | * | |
283 | * Shutdown everything and perform a clean system power_off. | |
284 | */ | |
285 | void kernel_power_off(void) | |
286 | { | |
287 | kernel_shutdown_prepare(SYSTEM_POWER_OFF); | |
288 | if (pm_power_off_prepare) | |
289 | pm_power_off_prepare(); | |
290 | migrate_to_reboot_cpu(); | |
291 | syscore_shutdown(); | |
972ee83d | 292 | pr_emerg("Power down\n"); |
15d94b82 RH |
293 | kmsg_dump(KMSG_DUMP_POWEROFF); |
294 | machine_power_off(); | |
295 | } | |
296 | EXPORT_SYMBOL_GPL(kernel_power_off); | |
297 | ||
55f2503c | 298 | DEFINE_MUTEX(system_transition_mutex); |
15d94b82 RH |
299 | |
300 | /* | |
301 | * Reboot system call: for obvious reasons only root may call it, | |
302 | * and even root needs to set up some magic numbers in the registers | |
303 | * so that some mistake won't make this reboot the whole machine. | |
304 | * You can also set the meaning of the ctrl-alt-del-key here. | |
305 | * | |
306 | * reboot doesn't sync: do that yourself before calling this. | |
307 | */ | |
308 | SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd, | |
309 | void __user *, arg) | |
310 | { | |
311 | struct pid_namespace *pid_ns = task_active_pid_ns(current); | |
312 | char buffer[256]; | |
313 | int ret = 0; | |
314 | ||
315 | /* We only trust the superuser with rebooting the system. */ | |
316 | if (!ns_capable(pid_ns->user_ns, CAP_SYS_BOOT)) | |
317 | return -EPERM; | |
318 | ||
319 | /* For safety, we require "magic" arguments. */ | |
320 | if (magic1 != LINUX_REBOOT_MAGIC1 || | |
972ee83d RH |
321 | (magic2 != LINUX_REBOOT_MAGIC2 && |
322 | magic2 != LINUX_REBOOT_MAGIC2A && | |
15d94b82 | 323 | magic2 != LINUX_REBOOT_MAGIC2B && |
972ee83d | 324 | magic2 != LINUX_REBOOT_MAGIC2C)) |
15d94b82 RH |
325 | return -EINVAL; |
326 | ||
327 | /* | |
328 | * If pid namespaces are enabled and the current task is in a child | |
329 | * pid_namespace, the command is handled by reboot_pid_ns() which will | |
330 | * call do_exit(). | |
331 | */ | |
332 | ret = reboot_pid_ns(pid_ns, cmd); | |
333 | if (ret) | |
334 | return ret; | |
335 | ||
336 | /* Instead of trying to make the power_off code look like | |
337 | * halt when pm_power_off is not set do it the easy way. | |
338 | */ | |
339 | if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off) | |
340 | cmd = LINUX_REBOOT_CMD_HALT; | |
341 | ||
55f2503c | 342 | mutex_lock(&system_transition_mutex); |
15d94b82 RH |
343 | switch (cmd) { |
344 | case LINUX_REBOOT_CMD_RESTART: | |
345 | kernel_restart(NULL); | |
346 | break; | |
347 | ||
348 | case LINUX_REBOOT_CMD_CAD_ON: | |
349 | C_A_D = 1; | |
350 | break; | |
351 | ||
352 | case LINUX_REBOOT_CMD_CAD_OFF: | |
353 | C_A_D = 0; | |
354 | break; | |
355 | ||
356 | case LINUX_REBOOT_CMD_HALT: | |
357 | kernel_halt(); | |
358 | do_exit(0); | |
359 | panic("cannot halt"); | |
360 | ||
361 | case LINUX_REBOOT_CMD_POWER_OFF: | |
362 | kernel_power_off(); | |
363 | do_exit(0); | |
364 | break; | |
365 | ||
366 | case LINUX_REBOOT_CMD_RESTART2: | |
972ee83d RH |
367 | ret = strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1); |
368 | if (ret < 0) { | |
15d94b82 RH |
369 | ret = -EFAULT; |
370 | break; | |
371 | } | |
372 | buffer[sizeof(buffer) - 1] = '\0'; | |
373 | ||
374 | kernel_restart(buffer); | |
375 | break; | |
376 | ||
2965faa5 | 377 | #ifdef CONFIG_KEXEC_CORE |
15d94b82 RH |
378 | case LINUX_REBOOT_CMD_KEXEC: |
379 | ret = kernel_kexec(); | |
380 | break; | |
381 | #endif | |
382 | ||
383 | #ifdef CONFIG_HIBERNATION | |
384 | case LINUX_REBOOT_CMD_SW_SUSPEND: | |
385 | ret = hibernate(); | |
386 | break; | |
387 | #endif | |
388 | ||
389 | default: | |
390 | ret = -EINVAL; | |
391 | break; | |
392 | } | |
55f2503c | 393 | mutex_unlock(&system_transition_mutex); |
15d94b82 RH |
394 | return ret; |
395 | } | |
396 | ||
397 | static void deferred_cad(struct work_struct *dummy) | |
398 | { | |
399 | kernel_restart(NULL); | |
400 | } | |
401 | ||
402 | /* | |
403 | * This function gets called by ctrl-alt-del - ie the keyboard interrupt. | |
404 | * As it's called within an interrupt, it may NOT sync: the only choice | |
405 | * is whether to reboot at once, or just ignore the ctrl-alt-del. | |
406 | */ | |
407 | void ctrl_alt_del(void) | |
408 | { | |
409 | static DECLARE_WORK(cad_work, deferred_cad); | |
410 | ||
411 | if (C_A_D) | |
412 | schedule_work(&cad_work); | |
413 | else | |
414 | kill_cad_pid(SIGINT, 1); | |
415 | } | |
416 | ||
417 | char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff"; | |
7a54f46b | 418 | static const char reboot_cmd[] = "/sbin/reboot"; |
15d94b82 | 419 | |
7a54f46b | 420 | static int run_cmd(const char *cmd) |
15d94b82 RH |
421 | { |
422 | char **argv; | |
423 | static char *envp[] = { | |
424 | "HOME=/", | |
425 | "PATH=/sbin:/bin:/usr/sbin:/usr/bin", | |
426 | NULL | |
427 | }; | |
428 | int ret; | |
7a54f46b | 429 | argv = argv_split(GFP_KERNEL, cmd, NULL); |
15d94b82 RH |
430 | if (argv) { |
431 | ret = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_EXEC); | |
432 | argv_free(argv); | |
433 | } else { | |
15d94b82 RH |
434 | ret = -ENOMEM; |
435 | } | |
436 | ||
7a54f46b JS |
437 | return ret; |
438 | } | |
439 | ||
440 | static int __orderly_reboot(void) | |
441 | { | |
442 | int ret; | |
443 | ||
444 | ret = run_cmd(reboot_cmd); | |
445 | ||
446 | if (ret) { | |
447 | pr_warn("Failed to start orderly reboot: forcing the issue\n"); | |
448 | emergency_sync(); | |
449 | kernel_restart(NULL); | |
450 | } | |
451 | ||
452 | return ret; | |
453 | } | |
454 | ||
455 | static int __orderly_poweroff(bool force) | |
456 | { | |
457 | int ret; | |
458 | ||
459 | ret = run_cmd(poweroff_cmd); | |
460 | ||
15d94b82 | 461 | if (ret && force) { |
972ee83d | 462 | pr_warn("Failed to start orderly shutdown: forcing the issue\n"); |
7a54f46b | 463 | |
15d94b82 RH |
464 | /* |
465 | * I guess this should try to kick off some daemon to sync and | |
466 | * poweroff asap. Or not even bother syncing if we're doing an | |
467 | * emergency shutdown? | |
468 | */ | |
469 | emergency_sync(); | |
470 | kernel_power_off(); | |
471 | } | |
472 | ||
473 | return ret; | |
474 | } | |
475 | ||
476 | static bool poweroff_force; | |
477 | ||
478 | static void poweroff_work_func(struct work_struct *work) | |
479 | { | |
480 | __orderly_poweroff(poweroff_force); | |
481 | } | |
482 | ||
483 | static DECLARE_WORK(poweroff_work, poweroff_work_func); | |
484 | ||
485 | /** | |
486 | * orderly_poweroff - Trigger an orderly system poweroff | |
487 | * @force: force poweroff if command execution fails | |
488 | * | |
489 | * This may be called from any context to trigger a system shutdown. | |
490 | * If the orderly shutdown fails, it will force an immediate shutdown. | |
491 | */ | |
7a54f46b | 492 | void orderly_poweroff(bool force) |
15d94b82 RH |
493 | { |
494 | if (force) /* do not override the pending "true" */ | |
495 | poweroff_force = true; | |
496 | schedule_work(&poweroff_work); | |
15d94b82 RH |
497 | } |
498 | EXPORT_SYMBOL_GPL(orderly_poweroff); | |
1b3a5d02 | 499 | |
7a54f46b JS |
500 | static void reboot_work_func(struct work_struct *work) |
501 | { | |
502 | __orderly_reboot(); | |
503 | } | |
504 | ||
505 | static DECLARE_WORK(reboot_work, reboot_work_func); | |
506 | ||
507 | /** | |
508 | * orderly_reboot - Trigger an orderly system reboot | |
509 | * | |
510 | * This may be called from any context to trigger a system reboot. | |
511 | * If the orderly reboot fails, it will force an immediate reboot. | |
512 | */ | |
513 | void orderly_reboot(void) | |
514 | { | |
515 | schedule_work(&reboot_work); | |
516 | } | |
517 | EXPORT_SYMBOL_GPL(orderly_reboot); | |
518 | ||
1b3a5d02 RH |
519 | static int __init reboot_setup(char *str) |
520 | { | |
521 | for (;;) { | |
522 | /* | |
523 | * Having anything passed on the command line via | |
524 | * reboot= will cause us to disable DMI checking | |
525 | * below. | |
526 | */ | |
527 | reboot_default = 0; | |
528 | ||
529 | switch (*str) { | |
530 | case 'w': | |
531 | reboot_mode = REBOOT_WARM; | |
532 | break; | |
533 | ||
534 | case 'c': | |
535 | reboot_mode = REBOOT_COLD; | |
536 | break; | |
537 | ||
538 | case 'h': | |
539 | reboot_mode = REBOOT_HARD; | |
540 | break; | |
541 | ||
542 | case 's': | |
616feab7 FF |
543 | { |
544 | int rc; | |
545 | ||
546 | if (isdigit(*(str+1))) { | |
547 | rc = kstrtoint(str+1, 0, &reboot_cpu); | |
548 | if (rc) | |
549 | return rc; | |
550 | } else if (str[1] == 'm' && str[2] == 'p' && | |
551 | isdigit(*(str+3))) { | |
552 | rc = kstrtoint(str+3, 0, &reboot_cpu); | |
553 | if (rc) | |
554 | return rc; | |
555 | } else | |
1b3a5d02 RH |
556 | reboot_mode = REBOOT_SOFT; |
557 | break; | |
616feab7 | 558 | } |
1b3a5d02 RH |
559 | case 'g': |
560 | reboot_mode = REBOOT_GPIO; | |
561 | break; | |
562 | ||
563 | case 'b': | |
564 | case 'a': | |
565 | case 'k': | |
566 | case 't': | |
567 | case 'e': | |
568 | case 'p': | |
569 | reboot_type = *str; | |
570 | break; | |
571 | ||
572 | case 'f': | |
573 | reboot_force = 1; | |
574 | break; | |
575 | } | |
576 | ||
577 | str = strchr(str, ','); | |
578 | if (str) | |
579 | str++; | |
580 | else | |
581 | break; | |
582 | } | |
583 | return 1; | |
584 | } | |
585 | __setup("reboot=", reboot_setup); |