1 // SPDX-License-Identifier: GPL-2.0-only
3 * linux/kernel/reboot.c
5 * Copyright (C) 2013 Linus Torvalds
8 #define pr_fmt(fmt) "reboot: " fmt
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>
23 * this indicates whether you can reboot with ctrl-alt-del: the default is yes
28 EXPORT_SYMBOL(cad_pid);
30 #if defined(CONFIG_ARM)
31 #define DEFAULT_REBOOT_MODE = REBOOT_HARD
33 #define DEFAULT_REBOOT_MODE
35 enum reboot_mode reboot_mode DEFAULT_REBOOT_MODE;
36 EXPORT_SYMBOL_GPL(reboot_mode);
37 enum reboot_mode panic_reboot_mode = REBOOT_UNDEFINED;
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.
46 int reboot_default = 1;
48 enum reboot_type reboot_type = BOOT_ACPI;
51 struct sys_off_handler {
52 struct notifier_block nb;
53 int (*sys_off_cb)(struct sys_off_data *data);
55 enum sys_off_mode mode;
61 * Temporary stub that prevents linkage failure while we're in process
62 * of removing all uses of legacy pm_power_off() around the kernel.
64 void __weak (*pm_power_off)(void);
67 * emergency_restart - reboot the system
69 * Without shutting down any hardware or taking any locks
70 * reboot the system. This is called when we know we are in
71 * trouble so this is our best effort to reboot. This is
72 * safe to call in interrupt context.
74 void emergency_restart(void)
76 kmsg_dump(KMSG_DUMP_EMERG);
77 machine_emergency_restart();
79 EXPORT_SYMBOL_GPL(emergency_restart);
81 void kernel_restart_prepare(char *cmd)
83 blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd);
84 system_state = SYSTEM_RESTART;
85 usermodehelper_disable();
90 * register_reboot_notifier - Register function to be called at reboot time
91 * @nb: Info about notifier function to be called
93 * Registers a function with the list of functions
94 * to be called at reboot time.
96 * Currently always returns zero, as blocking_notifier_chain_register()
97 * always returns zero.
99 int register_reboot_notifier(struct notifier_block *nb)
101 return blocking_notifier_chain_register(&reboot_notifier_list, nb);
103 EXPORT_SYMBOL(register_reboot_notifier);
106 * unregister_reboot_notifier - Unregister previously registered reboot notifier
107 * @nb: Hook to be unregistered
109 * Unregisters a previously registered reboot
112 * Returns zero on success, or %-ENOENT on failure.
114 int unregister_reboot_notifier(struct notifier_block *nb)
116 return blocking_notifier_chain_unregister(&reboot_notifier_list, nb);
118 EXPORT_SYMBOL(unregister_reboot_notifier);
120 static void devm_unregister_reboot_notifier(struct device *dev, void *res)
122 WARN_ON(unregister_reboot_notifier(*(struct notifier_block **)res));
125 int devm_register_reboot_notifier(struct device *dev, struct notifier_block *nb)
127 struct notifier_block **rcnb;
130 rcnb = devres_alloc(devm_unregister_reboot_notifier,
131 sizeof(*rcnb), GFP_KERNEL);
135 ret = register_reboot_notifier(nb);
138 devres_add(dev, rcnb);
145 EXPORT_SYMBOL(devm_register_reboot_notifier);
148 * Notifier list for kernel code which wants to be called
149 * to restart the system.
151 static ATOMIC_NOTIFIER_HEAD(restart_handler_list);
154 * register_restart_handler - Register function to be called to reset
156 * @nb: Info about handler function to be called
157 * @nb->priority: Handler priority. Handlers should follow the
158 * following guidelines for setting priorities.
159 * 0: Restart handler of last resort,
160 * with limited restart capabilities
161 * 128: Default restart handler; use if no other
162 * restart handler is expected to be available,
163 * and/or if restart functionality is
164 * sufficient to restart the entire system
165 * 255: Highest priority restart handler, will
166 * preempt all other restart handlers
168 * Registers a function with code to be called to restart the
171 * Registered functions will be called from machine_restart as last
172 * step of the restart sequence (if the architecture specific
173 * machine_restart function calls do_kernel_restart - see below
175 * Registered functions are expected to restart the system immediately.
176 * If more than one function is registered, the restart handler priority
177 * selects which function will be called first.
179 * Restart handlers are expected to be registered from non-architecture
180 * code, typically from drivers. A typical use case would be a system
181 * where restart functionality is provided through a watchdog. Multiple
182 * restart handlers may exist; for example, one restart handler might
183 * restart the entire system, while another only restarts the CPU.
184 * In such cases, the restart handler which only restarts part of the
185 * hardware is expected to register with low priority to ensure that
186 * it only runs if no other means to restart the system is available.
188 * Currently always returns zero, as atomic_notifier_chain_register()
189 * always returns zero.
191 int register_restart_handler(struct notifier_block *nb)
193 return atomic_notifier_chain_register(&restart_handler_list, nb);
195 EXPORT_SYMBOL(register_restart_handler);
198 * unregister_restart_handler - Unregister previously registered
200 * @nb: Hook to be unregistered
202 * Unregisters a previously registered restart handler function.
204 * Returns zero on success, or %-ENOENT on failure.
206 int unregister_restart_handler(struct notifier_block *nb)
208 return atomic_notifier_chain_unregister(&restart_handler_list, nb);
210 EXPORT_SYMBOL(unregister_restart_handler);
213 * do_kernel_restart - Execute kernel restart handler call chain
215 * Calls functions registered with register_restart_handler.
217 * Expected to be called from machine_restart as last step of the restart
220 * Restarts the system immediately if a restart handler function has been
221 * registered. Otherwise does nothing.
223 void do_kernel_restart(char *cmd)
225 atomic_notifier_call_chain(&restart_handler_list, reboot_mode, cmd);
228 void migrate_to_reboot_cpu(void)
230 /* The boot cpu is always logical cpu 0 */
231 int cpu = reboot_cpu;
233 cpu_hotplug_disable();
235 /* Make certain the cpu I'm about to reboot on is online */
236 if (!cpu_online(cpu))
237 cpu = cpumask_first(cpu_online_mask);
239 /* Prevent races with other tasks migrating this task */
240 current->flags |= PF_NO_SETAFFINITY;
242 /* Make certain I only run on the appropriate processor */
243 set_cpus_allowed_ptr(current, cpumask_of(cpu));
247 * kernel_restart - reboot the system
248 * @cmd: pointer to buffer containing command to execute for restart
251 * Shutdown everything and perform a clean reboot.
252 * This is not safe to call in interrupt context.
254 void kernel_restart(char *cmd)
256 kernel_restart_prepare(cmd);
257 migrate_to_reboot_cpu();
260 pr_emerg("Restarting system\n");
262 pr_emerg("Restarting system with command '%s'\n", cmd);
263 kmsg_dump(KMSG_DUMP_SHUTDOWN);
264 machine_restart(cmd);
266 EXPORT_SYMBOL_GPL(kernel_restart);
268 static void kernel_shutdown_prepare(enum system_states state)
270 blocking_notifier_call_chain(&reboot_notifier_list,
271 (state == SYSTEM_HALT) ? SYS_HALT : SYS_POWER_OFF, NULL);
272 system_state = state;
273 usermodehelper_disable();
277 * kernel_halt - halt the system
279 * Shutdown everything and perform a clean system halt.
281 void kernel_halt(void)
283 kernel_shutdown_prepare(SYSTEM_HALT);
284 migrate_to_reboot_cpu();
286 pr_emerg("System halted\n");
287 kmsg_dump(KMSG_DUMP_SHUTDOWN);
290 EXPORT_SYMBOL_GPL(kernel_halt);
293 * Notifier list for kernel code which wants to be called
294 * to prepare system for power off.
296 static BLOCKING_NOTIFIER_HEAD(power_off_prep_handler_list);
299 * Notifier list for kernel code which wants to be called
300 * to power off system.
302 static ATOMIC_NOTIFIER_HEAD(power_off_handler_list);
304 static int sys_off_notify(struct notifier_block *nb,
305 unsigned long mode, void *cmd)
307 struct sys_off_handler *handler;
308 struct sys_off_data data = {};
310 handler = container_of(nb, struct sys_off_handler, nb);
311 data.cb_data = handler->cb_data;
315 return handler->sys_off_cb(&data);
319 * register_sys_off_handler - Register sys-off handler
320 * @mode: Sys-off mode
321 * @priority: Handler priority
322 * @callback: Callback function
323 * @cb_data: Callback argument
325 * Registers system power-off or restart handler that will be invoked
326 * at the step corresponding to the given sys-off mode. Handler's callback
327 * should return NOTIFY_DONE to permit execution of the next handler in
328 * the call chain or NOTIFY_STOP to break the chain (in error case for
331 * Multiple handlers can be registered at the default priority level.
333 * Only one handler can be registered at the non-default priority level,
334 * otherwise ERR_PTR(-EBUSY) is returned.
336 * Returns a new instance of struct sys_off_handler on success, or
337 * an ERR_PTR()-encoded error code otherwise.
339 struct sys_off_handler *
340 register_sys_off_handler(enum sys_off_mode mode,
342 int (*callback)(struct sys_off_data *data),
345 struct sys_off_handler *handler;
348 handler = kzalloc(sizeof(*handler), GFP_KERNEL);
350 return ERR_PTR(-ENOMEM);
353 case SYS_OFF_MODE_POWER_OFF_PREPARE:
354 handler->list = &power_off_prep_handler_list;
355 handler->blocking = true;
358 case SYS_OFF_MODE_POWER_OFF:
359 handler->list = &power_off_handler_list;
362 case SYS_OFF_MODE_RESTART:
363 handler->list = &restart_handler_list;
368 return ERR_PTR(-EINVAL);
371 handler->nb.notifier_call = sys_off_notify;
372 handler->nb.priority = priority;
373 handler->sys_off_cb = callback;
374 handler->cb_data = cb_data;
375 handler->mode = mode;
377 if (handler->blocking) {
378 if (priority == SYS_OFF_PRIO_DEFAULT)
379 err = blocking_notifier_chain_register(handler->list,
382 err = blocking_notifier_chain_register_unique_prio(handler->list,
385 if (priority == SYS_OFF_PRIO_DEFAULT)
386 err = atomic_notifier_chain_register(handler->list,
389 err = atomic_notifier_chain_register_unique_prio(handler->list,
400 EXPORT_SYMBOL_GPL(register_sys_off_handler);
403 * unregister_sys_off_handler - Unregister sys-off handler
404 * @handler: Sys-off handler
406 * Unregisters given sys-off handler.
408 void unregister_sys_off_handler(struct sys_off_handler *handler)
415 if (handler->blocking)
416 err = blocking_notifier_chain_unregister(handler->list,
419 err = atomic_notifier_chain_unregister(handler->list,
422 /* sanity check, shall never happen */
427 EXPORT_SYMBOL_GPL(unregister_sys_off_handler);
429 static void devm_unregister_sys_off_handler(void *data)
431 struct sys_off_handler *handler = data;
433 unregister_sys_off_handler(handler);
437 * devm_register_sys_off_handler - Register sys-off handler
438 * @dev: Device that registers handler
439 * @mode: Sys-off mode
440 * @priority: Handler priority
441 * @callback: Callback function
442 * @cb_data: Callback argument
444 * Registers resource-managed sys-off handler.
446 * Returns zero on success, or error code on failure.
448 int devm_register_sys_off_handler(struct device *dev,
449 enum sys_off_mode mode,
451 int (*callback)(struct sys_off_data *data),
454 struct sys_off_handler *handler;
456 handler = register_sys_off_handler(mode, priority, callback, cb_data);
458 return PTR_ERR(handler);
460 return devm_add_action_or_reset(dev, devm_unregister_sys_off_handler,
463 EXPORT_SYMBOL_GPL(devm_register_sys_off_handler);
465 static struct sys_off_handler *platform_power_off_handler;
467 static int platform_power_off_notify(struct sys_off_data *data)
469 void (*platform_power_power_off_cb)(void) = data->cb_data;
471 platform_power_power_off_cb();
477 * register_platform_power_off - Register platform-level power-off callback
478 * @power_off: Power-off callback
480 * Registers power-off callback that will be called as last step
481 * of the power-off sequence. This callback is expected to be invoked
482 * for the last resort. Only one platform power-off callback is allowed
483 * to be registered at a time.
485 * Returns zero on success, or error code on failure.
487 int register_platform_power_off(void (*power_off)(void))
489 struct sys_off_handler *handler;
491 handler = register_sys_off_handler(SYS_OFF_MODE_POWER_OFF,
492 SYS_OFF_PRIO_PLATFORM,
493 platform_power_off_notify,
496 return PTR_ERR(handler);
498 platform_power_off_handler = handler;
502 EXPORT_SYMBOL_GPL(register_platform_power_off);
505 * unregister_platform_power_off - Unregister platform-level power-off callback
506 * @power_off: Power-off callback
508 * Unregisters previously registered platform power-off callback.
510 void unregister_platform_power_off(void (*power_off)(void))
512 if (platform_power_off_handler &&
513 platform_power_off_handler->cb_data == power_off) {
514 unregister_sys_off_handler(platform_power_off_handler);
515 platform_power_off_handler = NULL;
518 EXPORT_SYMBOL_GPL(unregister_platform_power_off);
520 static int legacy_pm_power_off(struct sys_off_data *data)
529 * Register sys-off handlers for legacy PM callbacks. This allows legacy
530 * PM callbacks co-exist with the new sys-off API.
532 * TODO: Remove legacy handlers once all legacy PM users will be switched
533 * to the sys-off based APIs.
535 static int __init legacy_pm_init(void)
537 register_sys_off_handler(SYS_OFF_MODE_POWER_OFF, SYS_OFF_PRIO_DEFAULT,
538 legacy_pm_power_off, NULL);
542 core_initcall(legacy_pm_init);
544 static void do_kernel_power_off_prepare(void)
546 blocking_notifier_call_chain(&power_off_prep_handler_list, 0, NULL);
550 * do_kernel_power_off - Execute kernel power-off handler call chain
552 * Expected to be called as last step of the power-off sequence.
554 * Powers off the system immediately if a power-off handler function has
555 * been registered. Otherwise does nothing.
557 void do_kernel_power_off(void)
559 atomic_notifier_call_chain(&power_off_handler_list, 0, NULL);
563 * kernel_can_power_off - check whether system can be powered off
565 * Returns true if power-off handler is registered and system can be
566 * powered off, false otherwise.
568 bool kernel_can_power_off(void)
570 return !atomic_notifier_call_chain_is_empty(&power_off_handler_list);
572 EXPORT_SYMBOL_GPL(kernel_can_power_off);
575 * kernel_power_off - power_off the system
577 * Shutdown everything and perform a clean system power_off.
579 void kernel_power_off(void)
581 kernel_shutdown_prepare(SYSTEM_POWER_OFF);
582 do_kernel_power_off_prepare();
583 migrate_to_reboot_cpu();
585 pr_emerg("Power down\n");
586 kmsg_dump(KMSG_DUMP_SHUTDOWN);
589 EXPORT_SYMBOL_GPL(kernel_power_off);
591 DEFINE_MUTEX(system_transition_mutex);
594 * Reboot system call: for obvious reasons only root may call it,
595 * and even root needs to set up some magic numbers in the registers
596 * so that some mistake won't make this reboot the whole machine.
597 * You can also set the meaning of the ctrl-alt-del-key here.
599 * reboot doesn't sync: do that yourself before calling this.
601 SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd,
604 struct pid_namespace *pid_ns = task_active_pid_ns(current);
608 /* We only trust the superuser with rebooting the system. */
609 if (!ns_capable(pid_ns->user_ns, CAP_SYS_BOOT))
612 /* For safety, we require "magic" arguments. */
613 if (magic1 != LINUX_REBOOT_MAGIC1 ||
614 (magic2 != LINUX_REBOOT_MAGIC2 &&
615 magic2 != LINUX_REBOOT_MAGIC2A &&
616 magic2 != LINUX_REBOOT_MAGIC2B &&
617 magic2 != LINUX_REBOOT_MAGIC2C))
621 * If pid namespaces are enabled and the current task is in a child
622 * pid_namespace, the command is handled by reboot_pid_ns() which will
625 ret = reboot_pid_ns(pid_ns, cmd);
629 /* Instead of trying to make the power_off code look like
630 * halt when pm_power_off is not set do it the easy way.
632 if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !kernel_can_power_off())
633 cmd = LINUX_REBOOT_CMD_HALT;
635 mutex_lock(&system_transition_mutex);
637 case LINUX_REBOOT_CMD_RESTART:
638 kernel_restart(NULL);
641 case LINUX_REBOOT_CMD_CAD_ON:
645 case LINUX_REBOOT_CMD_CAD_OFF:
649 case LINUX_REBOOT_CMD_HALT:
653 case LINUX_REBOOT_CMD_POWER_OFF:
658 case LINUX_REBOOT_CMD_RESTART2:
659 ret = strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1);
664 buffer[sizeof(buffer) - 1] = '\0';
666 kernel_restart(buffer);
669 #ifdef CONFIG_KEXEC_CORE
670 case LINUX_REBOOT_CMD_KEXEC:
671 ret = kernel_kexec();
675 #ifdef CONFIG_HIBERNATION
676 case LINUX_REBOOT_CMD_SW_SUSPEND:
685 mutex_unlock(&system_transition_mutex);
689 static void deferred_cad(struct work_struct *dummy)
691 kernel_restart(NULL);
695 * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
696 * As it's called within an interrupt, it may NOT sync: the only choice
697 * is whether to reboot at once, or just ignore the ctrl-alt-del.
699 void ctrl_alt_del(void)
701 static DECLARE_WORK(cad_work, deferred_cad);
704 schedule_work(&cad_work);
706 kill_cad_pid(SIGINT, 1);
709 char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";
710 static const char reboot_cmd[] = "/sbin/reboot";
712 static int run_cmd(const char *cmd)
715 static char *envp[] = {
717 "PATH=/sbin:/bin:/usr/sbin:/usr/bin",
721 argv = argv_split(GFP_KERNEL, cmd, NULL);
723 ret = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_EXEC);
732 static int __orderly_reboot(void)
736 ret = run_cmd(reboot_cmd);
739 pr_warn("Failed to start orderly reboot: forcing the issue\n");
741 kernel_restart(NULL);
747 static int __orderly_poweroff(bool force)
751 ret = run_cmd(poweroff_cmd);
754 pr_warn("Failed to start orderly shutdown: forcing the issue\n");
757 * I guess this should try to kick off some daemon to sync and
758 * poweroff asap. Or not even bother syncing if we're doing an
759 * emergency shutdown?
768 static bool poweroff_force;
770 static void poweroff_work_func(struct work_struct *work)
772 __orderly_poweroff(poweroff_force);
775 static DECLARE_WORK(poweroff_work, poweroff_work_func);
778 * orderly_poweroff - Trigger an orderly system poweroff
779 * @force: force poweroff if command execution fails
781 * This may be called from any context to trigger a system shutdown.
782 * If the orderly shutdown fails, it will force an immediate shutdown.
784 void orderly_poweroff(bool force)
786 if (force) /* do not override the pending "true" */
787 poweroff_force = true;
788 schedule_work(&poweroff_work);
790 EXPORT_SYMBOL_GPL(orderly_poweroff);
792 static void reboot_work_func(struct work_struct *work)
797 static DECLARE_WORK(reboot_work, reboot_work_func);
800 * orderly_reboot - Trigger an orderly system reboot
802 * This may be called from any context to trigger a system reboot.
803 * If the orderly reboot fails, it will force an immediate reboot.
805 void orderly_reboot(void)
807 schedule_work(&reboot_work);
809 EXPORT_SYMBOL_GPL(orderly_reboot);
812 * hw_failure_emergency_poweroff_func - emergency poweroff work after a known delay
813 * @work: work_struct associated with the emergency poweroff function
815 * This function is called in very critical situations to force
816 * a kernel poweroff after a configurable timeout value.
818 static void hw_failure_emergency_poweroff_func(struct work_struct *work)
821 * We have reached here after the emergency shutdown waiting period has
822 * expired. This means orderly_poweroff has not been able to shut off
823 * the system for some reason.
825 * Try to shut down the system immediately using kernel_power_off
828 pr_emerg("Hardware protection timed-out. Trying forced poweroff\n");
832 * Worst of the worst case trigger emergency restart
834 pr_emerg("Hardware protection shutdown failed. Trying emergency restart\n");
838 static DECLARE_DELAYED_WORK(hw_failure_emergency_poweroff_work,
839 hw_failure_emergency_poweroff_func);
842 * hw_failure_emergency_poweroff - Trigger an emergency system poweroff
844 * This may be called from any critical situation to trigger a system shutdown
845 * after a given period of time. If time is negative this is not scheduled.
847 static void hw_failure_emergency_poweroff(int poweroff_delay_ms)
849 if (poweroff_delay_ms <= 0)
851 schedule_delayed_work(&hw_failure_emergency_poweroff_work,
852 msecs_to_jiffies(poweroff_delay_ms));
856 * hw_protection_shutdown - Trigger an emergency system poweroff
858 * @reason: Reason of emergency shutdown to be printed.
859 * @ms_until_forced: Time to wait for orderly shutdown before tiggering a
860 * forced shudown. Negative value disables the forced
863 * Initiate an emergency system shutdown in order to protect hardware from
864 * further damage. Usage examples include a thermal protection or a voltage or
865 * current regulator failures.
866 * NOTE: The request is ignored if protection shutdown is already pending even
867 * if the previous request has given a large timeout for forced shutdown.
868 * Can be called from any context.
870 void hw_protection_shutdown(const char *reason, int ms_until_forced)
872 static atomic_t allow_proceed = ATOMIC_INIT(1);
874 pr_emerg("HARDWARE PROTECTION shutdown (%s)\n", reason);
876 /* Shutdown should be initiated only once. */
877 if (!atomic_dec_and_test(&allow_proceed))
881 * Queue a backup emergency shutdown in the event of
882 * orderly_poweroff failure
884 hw_failure_emergency_poweroff(ms_until_forced);
885 orderly_poweroff(true);
887 EXPORT_SYMBOL_GPL(hw_protection_shutdown);
889 static int __init reboot_setup(char *str)
892 enum reboot_mode *mode;
895 * Having anything passed on the command line via
896 * reboot= will cause us to disable DMI checking
901 if (!strncmp(str, "panic_", 6)) {
902 mode = &panic_reboot_mode;
923 * reboot_cpu is s[mp]#### with #### being the processor
924 * to be used for rebooting. Skip 's' or 'smp' prefix.
926 str += str[1] == 'm' && str[2] == 'p' ? 3 : 1;
928 if (isdigit(str[0])) {
929 int cpu = simple_strtoul(str, NULL, 0);
931 if (cpu >= num_possible_cpus()) {
932 pr_err("Ignoring the CPU number in reboot= option. "
933 "CPU %d exceeds possible cpu number %d\n",
934 cpu, num_possible_cpus());
960 str = strchr(str, ',');
968 __setup("reboot=", reboot_setup);
972 #define REBOOT_COLD_STR "cold"
973 #define REBOOT_WARM_STR "warm"
974 #define REBOOT_HARD_STR "hard"
975 #define REBOOT_SOFT_STR "soft"
976 #define REBOOT_GPIO_STR "gpio"
977 #define REBOOT_UNDEFINED_STR "undefined"
979 #define BOOT_TRIPLE_STR "triple"
980 #define BOOT_KBD_STR "kbd"
981 #define BOOT_BIOS_STR "bios"
982 #define BOOT_ACPI_STR "acpi"
983 #define BOOT_EFI_STR "efi"
984 #define BOOT_PCI_STR "pci"
986 static ssize_t mode_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
990 switch (reboot_mode) {
992 val = REBOOT_COLD_STR;
995 val = REBOOT_WARM_STR;
998 val = REBOOT_HARD_STR;
1001 val = REBOOT_SOFT_STR;
1004 val = REBOOT_GPIO_STR;
1007 val = REBOOT_UNDEFINED_STR;
1010 return sprintf(buf, "%s\n", val);
1012 static ssize_t mode_store(struct kobject *kobj, struct kobj_attribute *attr,
1013 const char *buf, size_t count)
1015 if (!capable(CAP_SYS_BOOT))
1018 if (!strncmp(buf, REBOOT_COLD_STR, strlen(REBOOT_COLD_STR)))
1019 reboot_mode = REBOOT_COLD;
1020 else if (!strncmp(buf, REBOOT_WARM_STR, strlen(REBOOT_WARM_STR)))
1021 reboot_mode = REBOOT_WARM;
1022 else if (!strncmp(buf, REBOOT_HARD_STR, strlen(REBOOT_HARD_STR)))
1023 reboot_mode = REBOOT_HARD;
1024 else if (!strncmp(buf, REBOOT_SOFT_STR, strlen(REBOOT_SOFT_STR)))
1025 reboot_mode = REBOOT_SOFT;
1026 else if (!strncmp(buf, REBOOT_GPIO_STR, strlen(REBOOT_GPIO_STR)))
1027 reboot_mode = REBOOT_GPIO;
1035 static struct kobj_attribute reboot_mode_attr = __ATTR_RW(mode);
1038 static ssize_t force_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
1040 return sprintf(buf, "%d\n", reboot_force);
1042 static ssize_t force_store(struct kobject *kobj, struct kobj_attribute *attr,
1043 const char *buf, size_t count)
1047 if (!capable(CAP_SYS_BOOT))
1050 if (kstrtobool(buf, &res))
1058 static struct kobj_attribute reboot_force_attr = __ATTR_RW(force);
1060 static ssize_t type_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
1064 switch (reboot_type) {
1066 val = BOOT_TRIPLE_STR;
1072 val = BOOT_BIOS_STR;
1075 val = BOOT_ACPI_STR;
1080 case BOOT_CF9_FORCE:
1084 val = REBOOT_UNDEFINED_STR;
1087 return sprintf(buf, "%s\n", val);
1089 static ssize_t type_store(struct kobject *kobj, struct kobj_attribute *attr,
1090 const char *buf, size_t count)
1092 if (!capable(CAP_SYS_BOOT))
1095 if (!strncmp(buf, BOOT_TRIPLE_STR, strlen(BOOT_TRIPLE_STR)))
1096 reboot_type = BOOT_TRIPLE;
1097 else if (!strncmp(buf, BOOT_KBD_STR, strlen(BOOT_KBD_STR)))
1098 reboot_type = BOOT_KBD;
1099 else if (!strncmp(buf, BOOT_BIOS_STR, strlen(BOOT_BIOS_STR)))
1100 reboot_type = BOOT_BIOS;
1101 else if (!strncmp(buf, BOOT_ACPI_STR, strlen(BOOT_ACPI_STR)))
1102 reboot_type = BOOT_ACPI;
1103 else if (!strncmp(buf, BOOT_EFI_STR, strlen(BOOT_EFI_STR)))
1104 reboot_type = BOOT_EFI;
1105 else if (!strncmp(buf, BOOT_PCI_STR, strlen(BOOT_PCI_STR)))
1106 reboot_type = BOOT_CF9_FORCE;
1114 static struct kobj_attribute reboot_type_attr = __ATTR_RW(type);
1118 static ssize_t cpu_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
1120 return sprintf(buf, "%d\n", reboot_cpu);
1122 static ssize_t cpu_store(struct kobject *kobj, struct kobj_attribute *attr,
1123 const char *buf, size_t count)
1125 unsigned int cpunum;
1128 if (!capable(CAP_SYS_BOOT))
1131 rc = kstrtouint(buf, 0, &cpunum);
1136 if (cpunum >= num_possible_cpus())
1140 reboot_cpu = cpunum;
1144 static struct kobj_attribute reboot_cpu_attr = __ATTR_RW(cpu);
1147 static struct attribute *reboot_attrs[] = {
1148 &reboot_mode_attr.attr,
1150 &reboot_force_attr.attr,
1151 &reboot_type_attr.attr,
1154 &reboot_cpu_attr.attr,
1159 static const struct attribute_group reboot_attr_group = {
1160 .attrs = reboot_attrs,
1163 static int __init reboot_ksysfs_init(void)
1165 struct kobject *reboot_kobj;
1168 reboot_kobj = kobject_create_and_add("reboot", kernel_kobj);
1172 ret = sysfs_create_group(reboot_kobj, &reboot_attr_group);
1174 kobject_put(reboot_kobj);
1180 late_initcall(reboot_ksysfs_init);