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/atomic.h>
11 : #include <linux/ctype.h>
12 : #include <linux/export.h>
13 : #include <linux/kexec.h>
14 : #include <linux/kmod.h>
15 : #include <linux/kmsg_dump.h>
16 : #include <linux/reboot.h>
17 : #include <linux/suspend.h>
18 : #include <linux/syscalls.h>
19 : #include <linux/syscore_ops.h>
20 : #include <linux/uaccess.h>
21 :
22 : /*
23 : * this indicates whether you can reboot with ctrl-alt-del: the default is yes
24 : */
25 :
26 : int C_A_D = 1;
27 : struct pid *cad_pid;
28 : EXPORT_SYMBOL(cad_pid);
29 :
30 : #if defined(CONFIG_ARM)
31 : #define DEFAULT_REBOOT_MODE = REBOOT_HARD
32 : #else
33 : #define DEFAULT_REBOOT_MODE
34 : #endif
35 : enum reboot_mode reboot_mode DEFAULT_REBOOT_MODE;
36 : EXPORT_SYMBOL_GPL(reboot_mode);
37 : enum reboot_mode panic_reboot_mode = REBOOT_UNDEFINED;
38 :
39 : /*
40 : * This variable is used privately to keep track of whether or not
41 : * reboot_type is still set to its default value (i.e., reboot= hasn't
42 : * been set on the command line). This is needed so that we can
43 : * suppress DMI scanning for reboot quirks. Without it, it's
44 : * impossible to override a faulty reboot quirk without recompiling.
45 : */
46 : int reboot_default = 1;
47 : int reboot_cpu;
48 : enum reboot_type reboot_type = BOOT_ACPI;
49 : int reboot_force;
50 :
51 : /*
52 : * If set, this is used for preparing the system to power off.
53 : */
54 :
55 : void (*pm_power_off_prepare)(void);
56 : EXPORT_SYMBOL_GPL(pm_power_off_prepare);
57 :
58 : /**
59 : * emergency_restart - reboot the system
60 : *
61 : * Without shutting down any hardware or taking any locks
62 : * reboot the system. This is called when we know we are in
63 : * trouble so this is our best effort to reboot. This is
64 : * safe to call in interrupt context.
65 : */
66 0 : void emergency_restart(void)
67 : {
68 0 : kmsg_dump(KMSG_DUMP_EMERG);
69 : machine_emergency_restart();
70 0 : }
71 : EXPORT_SYMBOL_GPL(emergency_restart);
72 :
73 0 : void kernel_restart_prepare(char *cmd)
74 : {
75 0 : blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd);
76 0 : system_state = SYSTEM_RESTART;
77 : usermodehelper_disable();
78 0 : device_shutdown();
79 0 : }
80 :
81 : /**
82 : * register_reboot_notifier - Register function to be called at reboot time
83 : * @nb: Info about notifier function to be called
84 : *
85 : * Registers a function with the list of functions
86 : * to be called at reboot time.
87 : *
88 : * Currently always returns zero, as blocking_notifier_chain_register()
89 : * always returns zero.
90 : */
91 2 : int register_reboot_notifier(struct notifier_block *nb)
92 : {
93 2 : return blocking_notifier_chain_register(&reboot_notifier_list, nb);
94 : }
95 : EXPORT_SYMBOL(register_reboot_notifier);
96 :
97 : /**
98 : * unregister_reboot_notifier - Unregister previously registered reboot notifier
99 : * @nb: Hook to be unregistered
100 : *
101 : * Unregisters a previously registered reboot
102 : * notifier function.
103 : *
104 : * Returns zero on success, or %-ENOENT on failure.
105 : */
106 0 : int unregister_reboot_notifier(struct notifier_block *nb)
107 : {
108 0 : return blocking_notifier_chain_unregister(&reboot_notifier_list, nb);
109 : }
110 : EXPORT_SYMBOL(unregister_reboot_notifier);
111 :
112 0 : static void devm_unregister_reboot_notifier(struct device *dev, void *res)
113 : {
114 0 : WARN_ON(unregister_reboot_notifier(*(struct notifier_block **)res));
115 0 : }
116 :
117 0 : int devm_register_reboot_notifier(struct device *dev, struct notifier_block *nb)
118 : {
119 : struct notifier_block **rcnb;
120 : int ret;
121 :
122 0 : rcnb = devres_alloc(devm_unregister_reboot_notifier,
123 : sizeof(*rcnb), GFP_KERNEL);
124 0 : if (!rcnb)
125 : return -ENOMEM;
126 :
127 0 : ret = register_reboot_notifier(nb);
128 0 : if (!ret) {
129 0 : *rcnb = nb;
130 0 : devres_add(dev, rcnb);
131 : } else {
132 0 : devres_free(rcnb);
133 : }
134 :
135 : return ret;
136 : }
137 : EXPORT_SYMBOL(devm_register_reboot_notifier);
138 :
139 : /*
140 : * Notifier list for kernel code which wants to be called
141 : * to restart the system.
142 : */
143 : static ATOMIC_NOTIFIER_HEAD(restart_handler_list);
144 :
145 : /**
146 : * register_restart_handler - Register function to be called to reset
147 : * the system
148 : * @nb: Info about handler function to be called
149 : * @nb->priority: Handler priority. Handlers should follow the
150 : * following guidelines for setting priorities.
151 : * 0: Restart handler of last resort,
152 : * with limited restart capabilities
153 : * 128: Default restart handler; use if no other
154 : * restart handler is expected to be available,
155 : * and/or if restart functionality is
156 : * sufficient to restart the entire system
157 : * 255: Highest priority restart handler, will
158 : * preempt all other restart handlers
159 : *
160 : * Registers a function with code to be called to restart the
161 : * system.
162 : *
163 : * Registered functions will be called from machine_restart as last
164 : * step of the restart sequence (if the architecture specific
165 : * machine_restart function calls do_kernel_restart - see below
166 : * for details).
167 : * Registered functions are expected to restart the system immediately.
168 : * If more than one function is registered, the restart handler priority
169 : * selects which function will be called first.
170 : *
171 : * Restart handlers are expected to be registered from non-architecture
172 : * code, typically from drivers. A typical use case would be a system
173 : * where restart functionality is provided through a watchdog. Multiple
174 : * restart handlers may exist; for example, one restart handler might
175 : * restart the entire system, while another only restarts the CPU.
176 : * In such cases, the restart handler which only restarts part of the
177 : * hardware is expected to register with low priority to ensure that
178 : * it only runs if no other means to restart the system is available.
179 : *
180 : * Currently always returns zero, as atomic_notifier_chain_register()
181 : * always returns zero.
182 : */
183 0 : int register_restart_handler(struct notifier_block *nb)
184 : {
185 0 : return atomic_notifier_chain_register(&restart_handler_list, nb);
186 : }
187 : EXPORT_SYMBOL(register_restart_handler);
188 :
189 : /**
190 : * unregister_restart_handler - Unregister previously registered
191 : * restart handler
192 : * @nb: Hook to be unregistered
193 : *
194 : * Unregisters a previously registered restart handler function.
195 : *
196 : * Returns zero on success, or %-ENOENT on failure.
197 : */
198 0 : int unregister_restart_handler(struct notifier_block *nb)
199 : {
200 0 : return atomic_notifier_chain_unregister(&restart_handler_list, nb);
201 : }
202 : EXPORT_SYMBOL(unregister_restart_handler);
203 :
204 : /**
205 : * do_kernel_restart - Execute kernel restart handler call chain
206 : *
207 : * Calls functions registered with register_restart_handler.
208 : *
209 : * Expected to be called from machine_restart as last step of the restart
210 : * sequence.
211 : *
212 : * Restarts the system immediately if a restart handler function has been
213 : * registered. Otherwise does nothing.
214 : */
215 0 : void do_kernel_restart(char *cmd)
216 : {
217 0 : atomic_notifier_call_chain(&restart_handler_list, reboot_mode, cmd);
218 0 : }
219 :
220 0 : void migrate_to_reboot_cpu(void)
221 : {
222 : /* The boot cpu is always logical cpu 0 */
223 1 : int cpu = reboot_cpu;
224 :
225 : cpu_hotplug_disable();
226 :
227 : /* Make certain the cpu I'm about to reboot on is online */
228 1 : if (!cpu_online(cpu))
229 0 : cpu = cpumask_first(cpu_online_mask);
230 :
231 : /* Prevent races with other tasks migrating this task */
232 1 : current->flags |= PF_NO_SETAFFINITY;
233 :
234 : /* Make certain I only run on the appropriate processor */
235 4 : set_cpus_allowed_ptr(current, cpumask_of(cpu));
236 0 : }
237 :
238 : /**
239 : * kernel_restart - reboot the system
240 : * @cmd: pointer to buffer containing command to execute for restart
241 : * or %NULL
242 : *
243 : * Shutdown everything and perform a clean reboot.
244 : * This is not safe to call in interrupt context.
245 : */
246 0 : void kernel_restart(char *cmd)
247 : {
248 0 : kernel_restart_prepare(cmd);
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 1 : static void kernel_shutdown_prepare(enum system_states state)
261 : {
262 1 : blocking_notifier_call_chain(&reboot_notifier_list,
263 : (state == SYSTEM_HALT) ? SYS_HALT : SYS_POWER_OFF, NULL);
264 1 : system_state = state;
265 : usermodehelper_disable();
266 1 : device_shutdown();
267 1 : }
268 : /**
269 : * kernel_halt - halt the system
270 : *
271 : * Shutdown everything and perform a clean system halt.
272 : */
273 1 : void kernel_halt(void)
274 : {
275 1 : kernel_shutdown_prepare(SYSTEM_HALT);
276 1 : migrate_to_reboot_cpu();
277 1 : syscore_shutdown();
278 1 : pr_emerg("System halted\n");
279 1 : kmsg_dump(KMSG_DUMP_SHUTDOWN);
280 1 : 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 0 : SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd,
313 : void __user *, arg)
314 : {
315 0 : struct pid_namespace *pid_ns = task_active_pid_ns(current);
316 : char buffer[256];
317 0 : int ret = 0;
318 :
319 : /* We only trust the superuser with rebooting the system. */
320 0 : if (!ns_capable(pid_ns->user_ns, CAP_SYS_BOOT))
321 : return -EPERM;
322 :
323 : /* For safety, we require "magic" arguments. */
324 0 : if (magic1 != LINUX_REBOOT_MAGIC1 ||
325 0 : (magic2 != LINUX_REBOOT_MAGIC2 &&
326 0 : 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 0 : ret = reboot_pid_ns(pid_ns, cmd);
337 0 : if (ret)
338 0 : 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 0 : if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off)
344 0 : cmd = LINUX_REBOOT_CMD_HALT;
345 :
346 0 : mutex_lock(&system_transition_mutex);
347 0 : switch (cmd) {
348 : case LINUX_REBOOT_CMD_RESTART:
349 0 : kernel_restart(NULL);
350 0 : break;
351 :
352 : case LINUX_REBOOT_CMD_CAD_ON:
353 0 : C_A_D = 1;
354 0 : break;
355 :
356 : case LINUX_REBOOT_CMD_CAD_OFF:
357 0 : C_A_D = 0;
358 0 : break;
359 :
360 : case LINUX_REBOOT_CMD_HALT:
361 0 : kernel_halt();
362 0 : do_exit(0);
363 :
364 : case LINUX_REBOOT_CMD_POWER_OFF:
365 0 : kernel_power_off();
366 0 : do_exit(0);
367 : break;
368 :
369 : case LINUX_REBOOT_CMD_RESTART2:
370 0 : ret = strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1);
371 0 : if (ret < 0) {
372 : ret = -EFAULT;
373 : break;
374 : }
375 0 : buffer[sizeof(buffer) - 1] = '\0';
376 :
377 0 : kernel_restart(buffer);
378 0 : break;
379 :
380 : #ifdef CONFIG_KEXEC_CORE
381 : case LINUX_REBOOT_CMD_KEXEC:
382 : ret = kernel_kexec();
383 : break;
384 : #endif
385 :
386 : #ifdef CONFIG_HIBERNATION
387 : case LINUX_REBOOT_CMD_SW_SUSPEND:
388 : ret = hibernate();
389 : break;
390 : #endif
391 :
392 : default:
393 : ret = -EINVAL;
394 : break;
395 : }
396 0 : mutex_unlock(&system_transition_mutex);
397 0 : return ret;
398 : }
399 :
400 0 : static void deferred_cad(struct work_struct *dummy)
401 : {
402 0 : kernel_restart(NULL);
403 0 : }
404 :
405 : /*
406 : * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
407 : * As it's called within an interrupt, it may NOT sync: the only choice
408 : * is whether to reboot at once, or just ignore the ctrl-alt-del.
409 : */
410 0 : void ctrl_alt_del(void)
411 : {
412 : static DECLARE_WORK(cad_work, deferred_cad);
413 :
414 0 : if (C_A_D)
415 : schedule_work(&cad_work);
416 : else
417 : kill_cad_pid(SIGINT, 1);
418 0 : }
419 :
420 : char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";
421 : static const char reboot_cmd[] = "/sbin/reboot";
422 :
423 0 : static int run_cmd(const char *cmd)
424 : {
425 : char **argv;
426 : static char *envp[] = {
427 : "HOME=/",
428 : "PATH=/sbin:/bin:/usr/sbin:/usr/bin",
429 : NULL
430 : };
431 : int ret;
432 0 : argv = argv_split(GFP_KERNEL, cmd, NULL);
433 0 : if (argv) {
434 0 : ret = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_EXEC);
435 0 : argv_free(argv);
436 : } else {
437 : ret = -ENOMEM;
438 : }
439 :
440 0 : return ret;
441 : }
442 :
443 0 : static int __orderly_reboot(void)
444 : {
445 : int ret;
446 :
447 0 : ret = run_cmd(reboot_cmd);
448 :
449 0 : if (ret) {
450 0 : pr_warn("Failed to start orderly reboot: forcing the issue\n");
451 0 : emergency_sync();
452 0 : kernel_restart(NULL);
453 : }
454 :
455 0 : return ret;
456 : }
457 :
458 0 : static int __orderly_poweroff(bool force)
459 : {
460 : int ret;
461 :
462 0 : ret = run_cmd(poweroff_cmd);
463 :
464 0 : if (ret && force) {
465 0 : pr_warn("Failed to start orderly shutdown: forcing the issue\n");
466 :
467 : /*
468 : * I guess this should try to kick off some daemon to sync and
469 : * poweroff asap. Or not even bother syncing if we're doing an
470 : * emergency shutdown?
471 : */
472 0 : emergency_sync();
473 0 : kernel_power_off();
474 : }
475 :
476 0 : return ret;
477 : }
478 :
479 : static bool poweroff_force;
480 :
481 0 : static void poweroff_work_func(struct work_struct *work)
482 : {
483 0 : __orderly_poweroff(poweroff_force);
484 0 : }
485 :
486 : static DECLARE_WORK(poweroff_work, poweroff_work_func);
487 :
488 : /**
489 : * orderly_poweroff - Trigger an orderly system poweroff
490 : * @force: force poweroff if command execution fails
491 : *
492 : * This may be called from any context to trigger a system shutdown.
493 : * If the orderly shutdown fails, it will force an immediate shutdown.
494 : */
495 0 : void orderly_poweroff(bool force)
496 : {
497 0 : if (force) /* do not override the pending "true" */
498 0 : poweroff_force = true;
499 0 : schedule_work(&poweroff_work);
500 0 : }
501 : EXPORT_SYMBOL_GPL(orderly_poweroff);
502 :
503 0 : static void reboot_work_func(struct work_struct *work)
504 : {
505 0 : __orderly_reboot();
506 0 : }
507 :
508 : static DECLARE_WORK(reboot_work, reboot_work_func);
509 :
510 : /**
511 : * orderly_reboot - Trigger an orderly system reboot
512 : *
513 : * This may be called from any context to trigger a system reboot.
514 : * If the orderly reboot fails, it will force an immediate reboot.
515 : */
516 0 : void orderly_reboot(void)
517 : {
518 0 : schedule_work(&reboot_work);
519 0 : }
520 : EXPORT_SYMBOL_GPL(orderly_reboot);
521 :
522 : /**
523 : * hw_failure_emergency_poweroff_func - emergency poweroff work after a known delay
524 : * @work: work_struct associated with the emergency poweroff function
525 : *
526 : * This function is called in very critical situations to force
527 : * a kernel poweroff after a configurable timeout value.
528 : */
529 0 : static void hw_failure_emergency_poweroff_func(struct work_struct *work)
530 : {
531 : /*
532 : * We have reached here after the emergency shutdown waiting period has
533 : * expired. This means orderly_poweroff has not been able to shut off
534 : * the system for some reason.
535 : *
536 : * Try to shut down the system immediately using kernel_power_off
537 : * if populated
538 : */
539 0 : pr_emerg("Hardware protection timed-out. Trying forced poweroff\n");
540 0 : kernel_power_off();
541 :
542 : /*
543 : * Worst of the worst case trigger emergency restart
544 : */
545 0 : pr_emerg("Hardware protection shutdown failed. Trying emergency restart\n");
546 : emergency_restart();
547 0 : }
548 :
549 : static DECLARE_DELAYED_WORK(hw_failure_emergency_poweroff_work,
550 : hw_failure_emergency_poweroff_func);
551 :
552 : /**
553 : * hw_failure_emergency_poweroff - Trigger an emergency system poweroff
554 : *
555 : * This may be called from any critical situation to trigger a system shutdown
556 : * after a given period of time. If time is negative this is not scheduled.
557 : */
558 0 : static void hw_failure_emergency_poweroff(int poweroff_delay_ms)
559 : {
560 0 : if (poweroff_delay_ms <= 0)
561 : return;
562 0 : schedule_delayed_work(&hw_failure_emergency_poweroff_work,
563 : msecs_to_jiffies(poweroff_delay_ms));
564 : }
565 :
566 : /**
567 : * hw_protection_shutdown - Trigger an emergency system poweroff
568 : *
569 : * @reason: Reason of emergency shutdown to be printed.
570 : * @ms_until_forced: Time to wait for orderly shutdown before tiggering a
571 : * forced shudown. Negative value disables the forced
572 : * shutdown.
573 : *
574 : * Initiate an emergency system shutdown in order to protect hardware from
575 : * further damage. Usage examples include a thermal protection or a voltage or
576 : * current regulator failures.
577 : * NOTE: The request is ignored if protection shutdown is already pending even
578 : * if the previous request has given a large timeout for forced shutdown.
579 : * Can be called from any context.
580 : */
581 0 : void hw_protection_shutdown(const char *reason, int ms_until_forced)
582 : {
583 : static atomic_t allow_proceed = ATOMIC_INIT(1);
584 :
585 0 : pr_emerg("HARDWARE PROTECTION shutdown (%s)\n", reason);
586 :
587 : /* Shutdown should be initiated only once. */
588 0 : if (!atomic_dec_and_test(&allow_proceed))
589 : return;
590 :
591 : /*
592 : * Queue a backup emergency shutdown in the event of
593 : * orderly_poweroff failure
594 : */
595 0 : hw_failure_emergency_poweroff(ms_until_forced);
596 : orderly_poweroff(true);
597 : }
598 : EXPORT_SYMBOL_GPL(hw_protection_shutdown);
599 :
600 0 : static int __init reboot_setup(char *str)
601 : {
602 0 : for (;;) {
603 : enum reboot_mode *mode;
604 :
605 : /*
606 : * Having anything passed on the command line via
607 : * reboot= will cause us to disable DMI checking
608 : * below.
609 : */
610 0 : reboot_default = 0;
611 :
612 0 : if (!strncmp(str, "panic_", 6)) {
613 0 : mode = &panic_reboot_mode;
614 0 : str += 6;
615 : } else {
616 : mode = &reboot_mode;
617 : }
618 :
619 0 : switch (*str) {
620 : case 'w':
621 0 : *mode = REBOOT_WARM;
622 0 : break;
623 :
624 : case 'c':
625 0 : *mode = REBOOT_COLD;
626 0 : break;
627 :
628 : case 'h':
629 0 : *mode = REBOOT_HARD;
630 0 : break;
631 :
632 : case 's':
633 : /*
634 : * reboot_cpu is s[mp]#### with #### being the processor
635 : * to be used for rebooting. Skip 's' or 'smp' prefix.
636 : */
637 0 : str += str[1] == 'm' && str[2] == 'p' ? 3 : 1;
638 :
639 0 : if (isdigit(str[0])) {
640 0 : int cpu = simple_strtoul(str, NULL, 0);
641 :
642 0 : if (cpu >= num_possible_cpus()) {
643 0 : pr_err("Ignoring the CPU number in reboot= option. "
644 : "CPU %d exceeds possible cpu number %d\n",
645 : cpu, num_possible_cpus());
646 0 : break;
647 : }
648 0 : reboot_cpu = cpu;
649 : } else
650 0 : *mode = REBOOT_SOFT;
651 : break;
652 :
653 : case 'g':
654 0 : *mode = REBOOT_GPIO;
655 0 : break;
656 :
657 : case 'b':
658 : case 'a':
659 : case 'k':
660 : case 't':
661 : case 'e':
662 : case 'p':
663 0 : reboot_type = *str;
664 0 : break;
665 :
666 : case 'f':
667 0 : reboot_force = 1;
668 0 : break;
669 : }
670 :
671 0 : str = strchr(str, ',');
672 0 : if (str)
673 0 : str++;
674 : else
675 : break;
676 : }
677 0 : return 1;
678 : }
679 : __setup("reboot=", reboot_setup);
680 :
681 : #ifdef CONFIG_SYSFS
682 :
683 : #define REBOOT_COLD_STR "cold"
684 : #define REBOOT_WARM_STR "warm"
685 : #define REBOOT_HARD_STR "hard"
686 : #define REBOOT_SOFT_STR "soft"
687 : #define REBOOT_GPIO_STR "gpio"
688 : #define REBOOT_UNDEFINED_STR "undefined"
689 :
690 : #define BOOT_TRIPLE_STR "triple"
691 : #define BOOT_KBD_STR "kbd"
692 : #define BOOT_BIOS_STR "bios"
693 : #define BOOT_ACPI_STR "acpi"
694 : #define BOOT_EFI_STR "efi"
695 : #define BOOT_PCI_STR "pci"
696 :
697 0 : static ssize_t mode_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
698 : {
699 : const char *val;
700 :
701 0 : switch (reboot_mode) {
702 : case REBOOT_COLD:
703 : val = REBOOT_COLD_STR;
704 : break;
705 : case REBOOT_WARM:
706 : val = REBOOT_WARM_STR;
707 : break;
708 : case REBOOT_HARD:
709 : val = REBOOT_HARD_STR;
710 : break;
711 : case REBOOT_SOFT:
712 : val = REBOOT_SOFT_STR;
713 : break;
714 : case REBOOT_GPIO:
715 : val = REBOOT_GPIO_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 mode_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, REBOOT_COLD_STR, strlen(REBOOT_COLD_STR)))
730 0 : reboot_mode = REBOOT_COLD;
731 0 : else if (!strncmp(buf, REBOOT_WARM_STR, strlen(REBOOT_WARM_STR)))
732 0 : reboot_mode = REBOOT_WARM;
733 0 : else if (!strncmp(buf, REBOOT_HARD_STR, strlen(REBOOT_HARD_STR)))
734 0 : reboot_mode = REBOOT_HARD;
735 0 : else if (!strncmp(buf, REBOOT_SOFT_STR, strlen(REBOOT_SOFT_STR)))
736 0 : reboot_mode = REBOOT_SOFT;
737 0 : else if (!strncmp(buf, REBOOT_GPIO_STR, strlen(REBOOT_GPIO_STR)))
738 0 : reboot_mode = REBOOT_GPIO;
739 : else
740 : return -EINVAL;
741 :
742 0 : reboot_default = 0;
743 :
744 0 : return count;
745 : }
746 : static struct kobj_attribute reboot_mode_attr = __ATTR_RW(mode);
747 :
748 : #ifdef CONFIG_X86
749 : static ssize_t force_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
750 : {
751 : return sprintf(buf, "%d\n", reboot_force);
752 : }
753 : static ssize_t force_store(struct kobject *kobj, struct kobj_attribute *attr,
754 : const char *buf, size_t count)
755 : {
756 : bool res;
757 :
758 : if (!capable(CAP_SYS_BOOT))
759 : return -EPERM;
760 :
761 : if (kstrtobool(buf, &res))
762 : return -EINVAL;
763 :
764 : reboot_default = 0;
765 : reboot_force = res;
766 :
767 : return count;
768 : }
769 : static struct kobj_attribute reboot_force_attr = __ATTR_RW(force);
770 :
771 : static ssize_t type_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
772 : {
773 : const char *val;
774 :
775 : switch (reboot_type) {
776 : case BOOT_TRIPLE:
777 : val = BOOT_TRIPLE_STR;
778 : break;
779 : case BOOT_KBD:
780 : val = BOOT_KBD_STR;
781 : break;
782 : case BOOT_BIOS:
783 : val = BOOT_BIOS_STR;
784 : break;
785 : case BOOT_ACPI:
786 : val = BOOT_ACPI_STR;
787 : break;
788 : case BOOT_EFI:
789 : val = BOOT_EFI_STR;
790 : break;
791 : case BOOT_CF9_FORCE:
792 : val = BOOT_PCI_STR;
793 : break;
794 : default:
795 : val = REBOOT_UNDEFINED_STR;
796 : }
797 :
798 : return sprintf(buf, "%s\n", val);
799 : }
800 : static ssize_t type_store(struct kobject *kobj, struct kobj_attribute *attr,
801 : const char *buf, size_t count)
802 : {
803 : if (!capable(CAP_SYS_BOOT))
804 : return -EPERM;
805 :
806 : if (!strncmp(buf, BOOT_TRIPLE_STR, strlen(BOOT_TRIPLE_STR)))
807 : reboot_type = BOOT_TRIPLE;
808 : else if (!strncmp(buf, BOOT_KBD_STR, strlen(BOOT_KBD_STR)))
809 : reboot_type = BOOT_KBD;
810 : else if (!strncmp(buf, BOOT_BIOS_STR, strlen(BOOT_BIOS_STR)))
811 : reboot_type = BOOT_BIOS;
812 : else if (!strncmp(buf, BOOT_ACPI_STR, strlen(BOOT_ACPI_STR)))
813 : reboot_type = BOOT_ACPI;
814 : else if (!strncmp(buf, BOOT_EFI_STR, strlen(BOOT_EFI_STR)))
815 : reboot_type = BOOT_EFI;
816 : else if (!strncmp(buf, BOOT_PCI_STR, strlen(BOOT_PCI_STR)))
817 : reboot_type = BOOT_CF9_FORCE;
818 : else
819 : return -EINVAL;
820 :
821 : reboot_default = 0;
822 :
823 : return count;
824 : }
825 : static struct kobj_attribute reboot_type_attr = __ATTR_RW(type);
826 : #endif
827 :
828 : #ifdef CONFIG_SMP
829 : static ssize_t cpu_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
830 : {
831 : return sprintf(buf, "%d\n", reboot_cpu);
832 : }
833 : static ssize_t cpu_store(struct kobject *kobj, struct kobj_attribute *attr,
834 : const char *buf, size_t count)
835 : {
836 : unsigned int cpunum;
837 : int rc;
838 :
839 : if (!capable(CAP_SYS_BOOT))
840 : return -EPERM;
841 :
842 : rc = kstrtouint(buf, 0, &cpunum);
843 :
844 : if (rc)
845 : return rc;
846 :
847 : if (cpunum >= num_possible_cpus())
848 : return -ERANGE;
849 :
850 : reboot_default = 0;
851 : reboot_cpu = cpunum;
852 :
853 : return count;
854 : }
855 : static struct kobj_attribute reboot_cpu_attr = __ATTR_RW(cpu);
856 : #endif
857 :
858 : static struct attribute *reboot_attrs[] = {
859 : &reboot_mode_attr.attr,
860 : #ifdef CONFIG_X86
861 : &reboot_force_attr.attr,
862 : &reboot_type_attr.attr,
863 : #endif
864 : #ifdef CONFIG_SMP
865 : &reboot_cpu_attr.attr,
866 : #endif
867 : NULL,
868 : };
869 :
870 : static const struct attribute_group reboot_attr_group = {
871 : .attrs = reboot_attrs,
872 : };
873 :
874 1 : static int __init reboot_ksysfs_init(void)
875 : {
876 : struct kobject *reboot_kobj;
877 : int ret;
878 :
879 1 : reboot_kobj = kobject_create_and_add("reboot", kernel_kobj);
880 1 : if (!reboot_kobj)
881 : return -ENOMEM;
882 :
883 1 : ret = sysfs_create_group(reboot_kobj, &reboot_attr_group);
884 1 : if (ret) {
885 0 : kobject_put(reboot_kobj);
886 0 : return ret;
887 : }
888 :
889 : return 0;
890 : }
891 : late_initcall(reboot_ksysfs_init);
892 :
893 : #endif
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