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1/*
2 * linux/kernel/reboot.c
3 *
4 * Copyright (C) 2013 Linus Torvalds
5 */
6
7#define pr_fmt(fmt) "reboot: " fmt
8
9#include <linux/ctype.h>
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
24int C_A_D = 1;
25struct pid *cad_pid;
26EXPORT_SYMBOL(cad_pid);
27
28#if defined(CONFIG_ARM) || defined(CONFIG_UNICORE32)
29#define DEFAULT_REBOOT_MODE = REBOOT_HARD
30#else
31#define DEFAULT_REBOOT_MODE
32#endif
33enum reboot_mode reboot_mode DEFAULT_REBOOT_MODE;
34
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 */
42int reboot_default = 1;
43int reboot_cpu;
44enum reboot_type reboot_type = BOOT_ACPI;
45int reboot_force;
46
47/*
48 * If set, this is used for preparing the system to power off.
49 */
50
51void (*pm_power_off_prepare)(void);
52
53/**
54 * emergency_restart - reboot the system
55 *
56 * Without shutting down any hardware or taking any locks
57 * reboot the system. This is called when we know we are in
58 * trouble so this is our best effort to reboot. This is
59 * safe to call in interrupt context.
60 */
61void emergency_restart(void)
62{
63 kmsg_dump(KMSG_DUMP_EMERG);
64 machine_emergency_restart();
65}
66EXPORT_SYMBOL_GPL(emergency_restart);
67
68void kernel_restart_prepare(char *cmd)
69{
70 blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd);
71 system_state = SYSTEM_RESTART;
72 usermodehelper_disable();
73 device_shutdown();
74}
75
76/**
77 * register_reboot_notifier - Register function to be called at reboot time
78 * @nb: Info about notifier function to be called
79 *
80 * Registers a function with the list of functions
81 * to be called at reboot time.
82 *
83 * Currently always returns zero, as blocking_notifier_chain_register()
84 * always returns zero.
85 */
86int register_reboot_notifier(struct notifier_block *nb)
87{
88 return blocking_notifier_chain_register(&reboot_notifier_list, nb);
89}
90EXPORT_SYMBOL(register_reboot_notifier);
91
92/**
93 * unregister_reboot_notifier - Unregister previously registered reboot notifier
94 * @nb: Hook to be unregistered
95 *
96 * Unregisters a previously registered reboot
97 * notifier function.
98 *
99 * Returns zero on success, or %-ENOENT on failure.
100 */
101int unregister_reboot_notifier(struct notifier_block *nb)
102{
103 return blocking_notifier_chain_unregister(&reboot_notifier_list, nb);
104}
105EXPORT_SYMBOL(unregister_reboot_notifier);
106
107void migrate_to_reboot_cpu(void)
108{
109 /* The boot cpu is always logical cpu 0 */
110 int cpu = reboot_cpu;
111
112 cpu_hotplug_disable();
113
114 /* Make certain the cpu I'm about to reboot on is online */
115 if (!cpu_online(cpu))
116 cpu = cpumask_first(cpu_online_mask);
117
118 /* Prevent races with other tasks migrating this task */
119 current->flags |= PF_NO_SETAFFINITY;
120
121 /* Make certain I only run on the appropriate processor */
122 set_cpus_allowed_ptr(current, cpumask_of(cpu));
123}
124
125/**
126 * kernel_restart - reboot the system
127 * @cmd: pointer to buffer containing command to execute for restart
128 * or %NULL
129 *
130 * Shutdown everything and perform a clean reboot.
131 * This is not safe to call in interrupt context.
132 */
133void kernel_restart(char *cmd)
134{
135 kernel_restart_prepare(cmd);
136 migrate_to_reboot_cpu();
137 syscore_shutdown();
138 if (!cmd)
139 pr_emerg("Restarting system\n");
140 else
141 pr_emerg("Restarting system with command '%s'\n", cmd);
142 kmsg_dump(KMSG_DUMP_RESTART);
143 machine_restart(cmd);
144}
145EXPORT_SYMBOL_GPL(kernel_restart);
146
147static void kernel_shutdown_prepare(enum system_states state)
148{
149 blocking_notifier_call_chain(&reboot_notifier_list,
150 (state == SYSTEM_HALT) ? SYS_HALT : SYS_POWER_OFF, NULL);
151 system_state = state;
152 usermodehelper_disable();
153 device_shutdown();
154}
155/**
156 * kernel_halt - halt the system
157 *
158 * Shutdown everything and perform a clean system halt.
159 */
160void kernel_halt(void)
161{
162 kernel_shutdown_prepare(SYSTEM_HALT);
163 migrate_to_reboot_cpu();
164 syscore_shutdown();
165 pr_emerg("System halted\n");
166 kmsg_dump(KMSG_DUMP_HALT);
167 machine_halt();
168}
169EXPORT_SYMBOL_GPL(kernel_halt);
170
171/**
172 * kernel_power_off - power_off the system
173 *
174 * Shutdown everything and perform a clean system power_off.
175 */
176void kernel_power_off(void)
177{
178 kernel_shutdown_prepare(SYSTEM_POWER_OFF);
179 if (pm_power_off_prepare)
180 pm_power_off_prepare();
181 migrate_to_reboot_cpu();
182 syscore_shutdown();
183 pr_emerg("Power down\n");
184 kmsg_dump(KMSG_DUMP_POWEROFF);
185 machine_power_off();
186}
187EXPORT_SYMBOL_GPL(kernel_power_off);
188
189static DEFINE_MUTEX(reboot_mutex);
190
191/*
192 * Reboot system call: for obvious reasons only root may call it,
193 * and even root needs to set up some magic numbers in the registers
194 * so that some mistake won't make this reboot the whole machine.
195 * You can also set the meaning of the ctrl-alt-del-key here.
196 *
197 * reboot doesn't sync: do that yourself before calling this.
198 */
199SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd,
200 void __user *, arg)
201{
202 struct pid_namespace *pid_ns = task_active_pid_ns(current);
203 char buffer[256];
204 int ret = 0;
205
206 /* We only trust the superuser with rebooting the system. */
207 if (!ns_capable(pid_ns->user_ns, CAP_SYS_BOOT))
208 return -EPERM;
209
210 /* For safety, we require "magic" arguments. */
211 if (magic1 != LINUX_REBOOT_MAGIC1 ||
212 (magic2 != LINUX_REBOOT_MAGIC2 &&
213 magic2 != LINUX_REBOOT_MAGIC2A &&
214 magic2 != LINUX_REBOOT_MAGIC2B &&
215 magic2 != LINUX_REBOOT_MAGIC2C))
216 return -EINVAL;
217
218 /*
219 * If pid namespaces are enabled and the current task is in a child
220 * pid_namespace, the command is handled by reboot_pid_ns() which will
221 * call do_exit().
222 */
223 ret = reboot_pid_ns(pid_ns, cmd);
224 if (ret)
225 return ret;
226
227 /* Instead of trying to make the power_off code look like
228 * halt when pm_power_off is not set do it the easy way.
229 */
230 if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off)
231 cmd = LINUX_REBOOT_CMD_HALT;
232
233 mutex_lock(&reboot_mutex);
234 switch (cmd) {
235 case LINUX_REBOOT_CMD_RESTART:
236 kernel_restart(NULL);
237 break;
238
239 case LINUX_REBOOT_CMD_CAD_ON:
240 C_A_D = 1;
241 break;
242
243 case LINUX_REBOOT_CMD_CAD_OFF:
244 C_A_D = 0;
245 break;
246
247 case LINUX_REBOOT_CMD_HALT:
248 kernel_halt();
249 do_exit(0);
250 panic("cannot halt");
251
252 case LINUX_REBOOT_CMD_POWER_OFF:
253 kernel_power_off();
254 do_exit(0);
255 break;
256
257 case LINUX_REBOOT_CMD_RESTART2:
258 ret = strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1);
259 if (ret < 0) {
260 ret = -EFAULT;
261 break;
262 }
263 buffer[sizeof(buffer) - 1] = '\0';
264
265 kernel_restart(buffer);
266 break;
267
268#ifdef CONFIG_KEXEC
269 case LINUX_REBOOT_CMD_KEXEC:
270 ret = kernel_kexec();
271 break;
272#endif
273
274#ifdef CONFIG_HIBERNATION
275 case LINUX_REBOOT_CMD_SW_SUSPEND:
276 ret = hibernate();
277 break;
278#endif
279
280 default:
281 ret = -EINVAL;
282 break;
283 }
284 mutex_unlock(&reboot_mutex);
285 return ret;
286}
287
288static void deferred_cad(struct work_struct *dummy)
289{
290 kernel_restart(NULL);
291}
292
293/*
294 * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
295 * As it's called within an interrupt, it may NOT sync: the only choice
296 * is whether to reboot at once, or just ignore the ctrl-alt-del.
297 */
298void ctrl_alt_del(void)
299{
300 static DECLARE_WORK(cad_work, deferred_cad);
301
302 if (C_A_D)
303 schedule_work(&cad_work);
304 else
305 kill_cad_pid(SIGINT, 1);
306}
307
308char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";
309
310static int __orderly_poweroff(bool force)
311{
312 char **argv;
313 static char *envp[] = {
314 "HOME=/",
315 "PATH=/sbin:/bin:/usr/sbin:/usr/bin",
316 NULL
317 };
318 int ret;
319
320 argv = argv_split(GFP_KERNEL, poweroff_cmd, NULL);
321 if (argv) {
322 ret = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_EXEC);
323 argv_free(argv);
324 } else {
325 ret = -ENOMEM;
326 }
327
328 if (ret && force) {
329 pr_warn("Failed to start orderly shutdown: forcing the issue\n");
330 /*
331 * I guess this should try to kick off some daemon to sync and
332 * poweroff asap. Or not even bother syncing if we're doing an
333 * emergency shutdown?
334 */
335 emergency_sync();
336 kernel_power_off();
337 }
338
339 return ret;
340}
341
342static bool poweroff_force;
343
344static void poweroff_work_func(struct work_struct *work)
345{
346 __orderly_poweroff(poweroff_force);
347}
348
349static DECLARE_WORK(poweroff_work, poweroff_work_func);
350
351/**
352 * orderly_poweroff - Trigger an orderly system poweroff
353 * @force: force poweroff if command execution fails
354 *
355 * This may be called from any context to trigger a system shutdown.
356 * If the orderly shutdown fails, it will force an immediate shutdown.
357 */
358int orderly_poweroff(bool force)
359{
360 if (force) /* do not override the pending "true" */
361 poweroff_force = true;
362 schedule_work(&poweroff_work);
363 return 0;
364}
365EXPORT_SYMBOL_GPL(orderly_poweroff);
366
367static int __init reboot_setup(char *str)
368{
369 for (;;) {
370 /*
371 * Having anything passed on the command line via
372 * reboot= will cause us to disable DMI checking
373 * below.
374 */
375 reboot_default = 0;
376
377 switch (*str) {
378 case 'w':
379 reboot_mode = REBOOT_WARM;
380 break;
381
382 case 'c':
383 reboot_mode = REBOOT_COLD;
384 break;
385
386 case 'h':
387 reboot_mode = REBOOT_HARD;
388 break;
389
390 case 's':
391 if (isdigit(*(str+1)))
392 reboot_cpu = simple_strtoul(str+1, NULL, 0);
393 else if (str[1] == 'm' && str[2] == 'p' &&
394 isdigit(*(str+3)))
395 reboot_cpu = simple_strtoul(str+3, NULL, 0);
396 else
397 reboot_mode = REBOOT_SOFT;
398 break;
399
400 case 'g':
401 reboot_mode = REBOOT_GPIO;
402 break;
403
404 case 'b':
405 case 'a':
406 case 'k':
407 case 't':
408 case 'e':
409 case 'p':
410 reboot_type = *str;
411 break;
412
413 case 'f':
414 reboot_force = 1;
415 break;
416 }
417
418 str = strchr(str, ',');
419 if (str)
420 str++;
421 else
422 break;
423 }
424 return 1;
425}
426__setup("reboot=", reboot_setup);
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
26static int C_A_D = 1;
27struct pid *cad_pid;
28EXPORT_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
35enum reboot_mode reboot_mode DEFAULT_REBOOT_MODE;
36EXPORT_SYMBOL_GPL(reboot_mode);
37enum 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 */
46int reboot_default = 1;
47int reboot_cpu;
48enum reboot_type reboot_type = BOOT_ACPI;
49int reboot_force;
50
51struct sys_off_handler {
52 struct notifier_block nb;
53 int (*sys_off_cb)(struct sys_off_data *data);
54 void *cb_data;
55 enum sys_off_mode mode;
56 bool blocking;
57 void *list;
58 struct device *dev;
59};
60
61/*
62 * This variable is used to indicate if a halt was initiated instead of a
63 * reboot when the reboot call was invoked with LINUX_REBOOT_CMD_POWER_OFF, but
64 * the system cannot be powered off. This allowes kernel_halt() to notify users
65 * of that.
66 */
67static bool poweroff_fallback_to_halt;
68
69/*
70 * Temporary stub that prevents linkage failure while we're in process
71 * of removing all uses of legacy pm_power_off() around the kernel.
72 */
73void __weak (*pm_power_off)(void);
74
75/**
76 * emergency_restart - reboot the system
77 *
78 * Without shutting down any hardware or taking any locks
79 * reboot the system. This is called when we know we are in
80 * trouble so this is our best effort to reboot. This is
81 * safe to call in interrupt context.
82 */
83void emergency_restart(void)
84{
85 kmsg_dump(KMSG_DUMP_EMERG);
86 system_state = SYSTEM_RESTART;
87 machine_emergency_restart();
88}
89EXPORT_SYMBOL_GPL(emergency_restart);
90
91void kernel_restart_prepare(char *cmd)
92{
93 blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd);
94 system_state = SYSTEM_RESTART;
95 usermodehelper_disable();
96 device_shutdown();
97}
98
99/**
100 * register_reboot_notifier - Register function to be called at reboot time
101 * @nb: Info about notifier function to be called
102 *
103 * Registers a function with the list of functions
104 * to be called at reboot time.
105 *
106 * Currently always returns zero, as blocking_notifier_chain_register()
107 * always returns zero.
108 */
109int register_reboot_notifier(struct notifier_block *nb)
110{
111 return blocking_notifier_chain_register(&reboot_notifier_list, nb);
112}
113EXPORT_SYMBOL(register_reboot_notifier);
114
115/**
116 * unregister_reboot_notifier - Unregister previously registered reboot notifier
117 * @nb: Hook to be unregistered
118 *
119 * Unregisters a previously registered reboot
120 * notifier function.
121 *
122 * Returns zero on success, or %-ENOENT on failure.
123 */
124int unregister_reboot_notifier(struct notifier_block *nb)
125{
126 return blocking_notifier_chain_unregister(&reboot_notifier_list, nb);
127}
128EXPORT_SYMBOL(unregister_reboot_notifier);
129
130static void devm_unregister_reboot_notifier(struct device *dev, void *res)
131{
132 WARN_ON(unregister_reboot_notifier(*(struct notifier_block **)res));
133}
134
135int devm_register_reboot_notifier(struct device *dev, struct notifier_block *nb)
136{
137 struct notifier_block **rcnb;
138 int ret;
139
140 rcnb = devres_alloc(devm_unregister_reboot_notifier,
141 sizeof(*rcnb), GFP_KERNEL);
142 if (!rcnb)
143 return -ENOMEM;
144
145 ret = register_reboot_notifier(nb);
146 if (!ret) {
147 *rcnb = nb;
148 devres_add(dev, rcnb);
149 } else {
150 devres_free(rcnb);
151 }
152
153 return ret;
154}
155EXPORT_SYMBOL(devm_register_reboot_notifier);
156
157/*
158 * Notifier list for kernel code which wants to be called
159 * to restart the system.
160 */
161static ATOMIC_NOTIFIER_HEAD(restart_handler_list);
162
163/**
164 * register_restart_handler - Register function to be called to reset
165 * the system
166 * @nb: Info about handler function to be called
167 * @nb->priority: Handler priority. Handlers should follow the
168 * following guidelines for setting priorities.
169 * 0: Restart handler of last resort,
170 * with limited restart capabilities
171 * 128: Default restart handler; use if no other
172 * restart handler is expected to be available,
173 * and/or if restart functionality is
174 * sufficient to restart the entire system
175 * 255: Highest priority restart handler, will
176 * preempt all other restart handlers
177 *
178 * Registers a function with code to be called to restart the
179 * system.
180 *
181 * Registered functions will be called from machine_restart as last
182 * step of the restart sequence (if the architecture specific
183 * machine_restart function calls do_kernel_restart - see below
184 * for details).
185 * Registered functions are expected to restart the system immediately.
186 * If more than one function is registered, the restart handler priority
187 * selects which function will be called first.
188 *
189 * Restart handlers are expected to be registered from non-architecture
190 * code, typically from drivers. A typical use case would be a system
191 * where restart functionality is provided through a watchdog. Multiple
192 * restart handlers may exist; for example, one restart handler might
193 * restart the entire system, while another only restarts the CPU.
194 * In such cases, the restart handler which only restarts part of the
195 * hardware is expected to register with low priority to ensure that
196 * it only runs if no other means to restart the system is available.
197 *
198 * Currently always returns zero, as atomic_notifier_chain_register()
199 * always returns zero.
200 */
201int register_restart_handler(struct notifier_block *nb)
202{
203 return atomic_notifier_chain_register(&restart_handler_list, nb);
204}
205EXPORT_SYMBOL(register_restart_handler);
206
207/**
208 * unregister_restart_handler - Unregister previously registered
209 * restart handler
210 * @nb: Hook to be unregistered
211 *
212 * Unregisters a previously registered restart handler function.
213 *
214 * Returns zero on success, or %-ENOENT on failure.
215 */
216int unregister_restart_handler(struct notifier_block *nb)
217{
218 return atomic_notifier_chain_unregister(&restart_handler_list, nb);
219}
220EXPORT_SYMBOL(unregister_restart_handler);
221
222/**
223 * do_kernel_restart - Execute kernel restart handler call chain
224 *
225 * Calls functions registered with register_restart_handler.
226 *
227 * Expected to be called from machine_restart as last step of the restart
228 * sequence.
229 *
230 * Restarts the system immediately if a restart handler function has been
231 * registered. Otherwise does nothing.
232 */
233void do_kernel_restart(char *cmd)
234{
235 atomic_notifier_call_chain(&restart_handler_list, reboot_mode, cmd);
236}
237
238void migrate_to_reboot_cpu(void)
239{
240 /* The boot cpu is always logical cpu 0 */
241 int cpu = reboot_cpu;
242
243 cpu_hotplug_disable();
244
245 /* Make certain the cpu I'm about to reboot on is online */
246 if (!cpu_online(cpu))
247 cpu = cpumask_first(cpu_online_mask);
248
249 /* Prevent races with other tasks migrating this task */
250 current->flags |= PF_NO_SETAFFINITY;
251
252 /* Make certain I only run on the appropriate processor */
253 set_cpus_allowed_ptr(current, cpumask_of(cpu));
254}
255
256/*
257 * Notifier list for kernel code which wants to be called
258 * to prepare system for restart.
259 */
260static BLOCKING_NOTIFIER_HEAD(restart_prep_handler_list);
261
262static void do_kernel_restart_prepare(void)
263{
264 blocking_notifier_call_chain(&restart_prep_handler_list, 0, NULL);
265}
266
267/**
268 * kernel_restart - reboot the system
269 * @cmd: pointer to buffer containing command to execute for restart
270 * or %NULL
271 *
272 * Shutdown everything and perform a clean reboot.
273 * This is not safe to call in interrupt context.
274 */
275void kernel_restart(char *cmd)
276{
277 kernel_restart_prepare(cmd);
278 do_kernel_restart_prepare();
279 migrate_to_reboot_cpu();
280 syscore_shutdown();
281 if (!cmd)
282 pr_emerg("Restarting system\n");
283 else
284 pr_emerg("Restarting system with command '%s'\n", cmd);
285 kmsg_dump(KMSG_DUMP_SHUTDOWN);
286 machine_restart(cmd);
287}
288EXPORT_SYMBOL_GPL(kernel_restart);
289
290static void kernel_shutdown_prepare(enum system_states state)
291{
292 blocking_notifier_call_chain(&reboot_notifier_list,
293 (state == SYSTEM_HALT) ? SYS_HALT : SYS_POWER_OFF, NULL);
294 system_state = state;
295 usermodehelper_disable();
296 device_shutdown();
297}
298/**
299 * kernel_halt - halt the system
300 *
301 * Shutdown everything and perform a clean system halt.
302 */
303void kernel_halt(void)
304{
305 kernel_shutdown_prepare(SYSTEM_HALT);
306 migrate_to_reboot_cpu();
307 syscore_shutdown();
308 if (poweroff_fallback_to_halt)
309 pr_emerg("Power off not available: System halted instead\n");
310 else
311 pr_emerg("System halted\n");
312 kmsg_dump(KMSG_DUMP_SHUTDOWN);
313 machine_halt();
314}
315EXPORT_SYMBOL_GPL(kernel_halt);
316
317/*
318 * Notifier list for kernel code which wants to be called
319 * to prepare system for power off.
320 */
321static BLOCKING_NOTIFIER_HEAD(power_off_prep_handler_list);
322
323/*
324 * Notifier list for kernel code which wants to be called
325 * to power off system.
326 */
327static ATOMIC_NOTIFIER_HEAD(power_off_handler_list);
328
329static int sys_off_notify(struct notifier_block *nb,
330 unsigned long mode, void *cmd)
331{
332 struct sys_off_handler *handler;
333 struct sys_off_data data = {};
334
335 handler = container_of(nb, struct sys_off_handler, nb);
336 data.cb_data = handler->cb_data;
337 data.mode = mode;
338 data.cmd = cmd;
339 data.dev = handler->dev;
340
341 return handler->sys_off_cb(&data);
342}
343
344static struct sys_off_handler platform_sys_off_handler;
345
346static struct sys_off_handler *alloc_sys_off_handler(int priority)
347{
348 struct sys_off_handler *handler;
349 gfp_t flags;
350
351 /*
352 * Platforms like m68k can't allocate sys_off handler dynamically
353 * at the early boot time because memory allocator isn't available yet.
354 */
355 if (priority == SYS_OFF_PRIO_PLATFORM) {
356 handler = &platform_sys_off_handler;
357 if (handler->cb_data)
358 return ERR_PTR(-EBUSY);
359 } else {
360 if (system_state > SYSTEM_RUNNING)
361 flags = GFP_ATOMIC;
362 else
363 flags = GFP_KERNEL;
364
365 handler = kzalloc(sizeof(*handler), flags);
366 if (!handler)
367 return ERR_PTR(-ENOMEM);
368 }
369
370 return handler;
371}
372
373static void free_sys_off_handler(struct sys_off_handler *handler)
374{
375 if (handler == &platform_sys_off_handler)
376 memset(handler, 0, sizeof(*handler));
377 else
378 kfree(handler);
379}
380
381/**
382 * register_sys_off_handler - Register sys-off handler
383 * @mode: Sys-off mode
384 * @priority: Handler priority
385 * @callback: Callback function
386 * @cb_data: Callback argument
387 *
388 * Registers system power-off or restart handler that will be invoked
389 * at the step corresponding to the given sys-off mode. Handler's callback
390 * should return NOTIFY_DONE to permit execution of the next handler in
391 * the call chain or NOTIFY_STOP to break the chain (in error case for
392 * example).
393 *
394 * Multiple handlers can be registered at the default priority level.
395 *
396 * Only one handler can be registered at the non-default priority level,
397 * otherwise ERR_PTR(-EBUSY) is returned.
398 *
399 * Returns a new instance of struct sys_off_handler on success, or
400 * an ERR_PTR()-encoded error code otherwise.
401 */
402struct sys_off_handler *
403register_sys_off_handler(enum sys_off_mode mode,
404 int priority,
405 int (*callback)(struct sys_off_data *data),
406 void *cb_data)
407{
408 struct sys_off_handler *handler;
409 int err;
410
411 handler = alloc_sys_off_handler(priority);
412 if (IS_ERR(handler))
413 return handler;
414
415 switch (mode) {
416 case SYS_OFF_MODE_POWER_OFF_PREPARE:
417 handler->list = &power_off_prep_handler_list;
418 handler->blocking = true;
419 break;
420
421 case SYS_OFF_MODE_POWER_OFF:
422 handler->list = &power_off_handler_list;
423 break;
424
425 case SYS_OFF_MODE_RESTART_PREPARE:
426 handler->list = &restart_prep_handler_list;
427 handler->blocking = true;
428 break;
429
430 case SYS_OFF_MODE_RESTART:
431 handler->list = &restart_handler_list;
432 break;
433
434 default:
435 free_sys_off_handler(handler);
436 return ERR_PTR(-EINVAL);
437 }
438
439 handler->nb.notifier_call = sys_off_notify;
440 handler->nb.priority = priority;
441 handler->sys_off_cb = callback;
442 handler->cb_data = cb_data;
443 handler->mode = mode;
444
445 if (handler->blocking) {
446 if (priority == SYS_OFF_PRIO_DEFAULT)
447 err = blocking_notifier_chain_register(handler->list,
448 &handler->nb);
449 else
450 err = blocking_notifier_chain_register_unique_prio(handler->list,
451 &handler->nb);
452 } else {
453 if (priority == SYS_OFF_PRIO_DEFAULT)
454 err = atomic_notifier_chain_register(handler->list,
455 &handler->nb);
456 else
457 err = atomic_notifier_chain_register_unique_prio(handler->list,
458 &handler->nb);
459 }
460
461 if (err) {
462 free_sys_off_handler(handler);
463 return ERR_PTR(err);
464 }
465
466 return handler;
467}
468EXPORT_SYMBOL_GPL(register_sys_off_handler);
469
470/**
471 * unregister_sys_off_handler - Unregister sys-off handler
472 * @handler: Sys-off handler
473 *
474 * Unregisters given sys-off handler.
475 */
476void unregister_sys_off_handler(struct sys_off_handler *handler)
477{
478 int err;
479
480 if (IS_ERR_OR_NULL(handler))
481 return;
482
483 if (handler->blocking)
484 err = blocking_notifier_chain_unregister(handler->list,
485 &handler->nb);
486 else
487 err = atomic_notifier_chain_unregister(handler->list,
488 &handler->nb);
489
490 /* sanity check, shall never happen */
491 WARN_ON(err);
492
493 free_sys_off_handler(handler);
494}
495EXPORT_SYMBOL_GPL(unregister_sys_off_handler);
496
497static void devm_unregister_sys_off_handler(void *data)
498{
499 struct sys_off_handler *handler = data;
500
501 unregister_sys_off_handler(handler);
502}
503
504/**
505 * devm_register_sys_off_handler - Register sys-off handler
506 * @dev: Device that registers handler
507 * @mode: Sys-off mode
508 * @priority: Handler priority
509 * @callback: Callback function
510 * @cb_data: Callback argument
511 *
512 * Registers resource-managed sys-off handler.
513 *
514 * Returns zero on success, or error code on failure.
515 */
516int devm_register_sys_off_handler(struct device *dev,
517 enum sys_off_mode mode,
518 int priority,
519 int (*callback)(struct sys_off_data *data),
520 void *cb_data)
521{
522 struct sys_off_handler *handler;
523
524 handler = register_sys_off_handler(mode, priority, callback, cb_data);
525 if (IS_ERR(handler))
526 return PTR_ERR(handler);
527 handler->dev = dev;
528
529 return devm_add_action_or_reset(dev, devm_unregister_sys_off_handler,
530 handler);
531}
532EXPORT_SYMBOL_GPL(devm_register_sys_off_handler);
533
534/**
535 * devm_register_power_off_handler - Register power-off handler
536 * @dev: Device that registers callback
537 * @callback: Callback function
538 * @cb_data: Callback's argument
539 *
540 * Registers resource-managed sys-off handler with a default priority
541 * and using power-off mode.
542 *
543 * Returns zero on success, or error code on failure.
544 */
545int devm_register_power_off_handler(struct device *dev,
546 int (*callback)(struct sys_off_data *data),
547 void *cb_data)
548{
549 return devm_register_sys_off_handler(dev,
550 SYS_OFF_MODE_POWER_OFF,
551 SYS_OFF_PRIO_DEFAULT,
552 callback, cb_data);
553}
554EXPORT_SYMBOL_GPL(devm_register_power_off_handler);
555
556/**
557 * devm_register_restart_handler - Register restart handler
558 * @dev: Device that registers callback
559 * @callback: Callback function
560 * @cb_data: Callback's argument
561 *
562 * Registers resource-managed sys-off handler with a default priority
563 * and using restart mode.
564 *
565 * Returns zero on success, or error code on failure.
566 */
567int devm_register_restart_handler(struct device *dev,
568 int (*callback)(struct sys_off_data *data),
569 void *cb_data)
570{
571 return devm_register_sys_off_handler(dev,
572 SYS_OFF_MODE_RESTART,
573 SYS_OFF_PRIO_DEFAULT,
574 callback, cb_data);
575}
576EXPORT_SYMBOL_GPL(devm_register_restart_handler);
577
578static struct sys_off_handler *platform_power_off_handler;
579
580static int platform_power_off_notify(struct sys_off_data *data)
581{
582 void (*platform_power_power_off_cb)(void) = data->cb_data;
583
584 platform_power_power_off_cb();
585
586 return NOTIFY_DONE;
587}
588
589/**
590 * register_platform_power_off - Register platform-level power-off callback
591 * @power_off: Power-off callback
592 *
593 * Registers power-off callback that will be called as last step
594 * of the power-off sequence. This callback is expected to be invoked
595 * for the last resort. Only one platform power-off callback is allowed
596 * to be registered at a time.
597 *
598 * Returns zero on success, or error code on failure.
599 */
600int register_platform_power_off(void (*power_off)(void))
601{
602 struct sys_off_handler *handler;
603
604 handler = register_sys_off_handler(SYS_OFF_MODE_POWER_OFF,
605 SYS_OFF_PRIO_PLATFORM,
606 platform_power_off_notify,
607 power_off);
608 if (IS_ERR(handler))
609 return PTR_ERR(handler);
610
611 platform_power_off_handler = handler;
612
613 return 0;
614}
615EXPORT_SYMBOL_GPL(register_platform_power_off);
616
617/**
618 * unregister_platform_power_off - Unregister platform-level power-off callback
619 * @power_off: Power-off callback
620 *
621 * Unregisters previously registered platform power-off callback.
622 */
623void unregister_platform_power_off(void (*power_off)(void))
624{
625 if (platform_power_off_handler &&
626 platform_power_off_handler->cb_data == power_off) {
627 unregister_sys_off_handler(platform_power_off_handler);
628 platform_power_off_handler = NULL;
629 }
630}
631EXPORT_SYMBOL_GPL(unregister_platform_power_off);
632
633static int legacy_pm_power_off(struct sys_off_data *data)
634{
635 if (pm_power_off)
636 pm_power_off();
637
638 return NOTIFY_DONE;
639}
640
641static void do_kernel_power_off_prepare(void)
642{
643 blocking_notifier_call_chain(&power_off_prep_handler_list, 0, NULL);
644}
645
646/**
647 * do_kernel_power_off - Execute kernel power-off handler call chain
648 *
649 * Expected to be called as last step of the power-off sequence.
650 *
651 * Powers off the system immediately if a power-off handler function has
652 * been registered. Otherwise does nothing.
653 */
654void do_kernel_power_off(void)
655{
656 struct sys_off_handler *sys_off = NULL;
657
658 /*
659 * Register sys-off handlers for legacy PM callback. This allows
660 * legacy PM callbacks temporary co-exist with the new sys-off API.
661 *
662 * TODO: Remove legacy handlers once all legacy PM users will be
663 * switched to the sys-off based APIs.
664 */
665 if (pm_power_off)
666 sys_off = register_sys_off_handler(SYS_OFF_MODE_POWER_OFF,
667 SYS_OFF_PRIO_DEFAULT,
668 legacy_pm_power_off, NULL);
669
670 atomic_notifier_call_chain(&power_off_handler_list, 0, NULL);
671
672 unregister_sys_off_handler(sys_off);
673}
674
675/**
676 * kernel_can_power_off - check whether system can be powered off
677 *
678 * Returns true if power-off handler is registered and system can be
679 * powered off, false otherwise.
680 */
681bool kernel_can_power_off(void)
682{
683 return !atomic_notifier_call_chain_is_empty(&power_off_handler_list) ||
684 pm_power_off;
685}
686EXPORT_SYMBOL_GPL(kernel_can_power_off);
687
688/**
689 * kernel_power_off - power_off the system
690 *
691 * Shutdown everything and perform a clean system power_off.
692 */
693void kernel_power_off(void)
694{
695 kernel_shutdown_prepare(SYSTEM_POWER_OFF);
696 do_kernel_power_off_prepare();
697 migrate_to_reboot_cpu();
698 syscore_shutdown();
699 pr_emerg("Power down\n");
700 kmsg_dump(KMSG_DUMP_SHUTDOWN);
701 machine_power_off();
702}
703EXPORT_SYMBOL_GPL(kernel_power_off);
704
705DEFINE_MUTEX(system_transition_mutex);
706
707/*
708 * Reboot system call: for obvious reasons only root may call it,
709 * and even root needs to set up some magic numbers in the registers
710 * so that some mistake won't make this reboot the whole machine.
711 * You can also set the meaning of the ctrl-alt-del-key here.
712 *
713 * reboot doesn't sync: do that yourself before calling this.
714 */
715SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd,
716 void __user *, arg)
717{
718 struct pid_namespace *pid_ns = task_active_pid_ns(current);
719 char buffer[256];
720 int ret = 0;
721
722 /* We only trust the superuser with rebooting the system. */
723 if (!ns_capable(pid_ns->user_ns, CAP_SYS_BOOT))
724 return -EPERM;
725
726 /* For safety, we require "magic" arguments. */
727 if (magic1 != LINUX_REBOOT_MAGIC1 ||
728 (magic2 != LINUX_REBOOT_MAGIC2 &&
729 magic2 != LINUX_REBOOT_MAGIC2A &&
730 magic2 != LINUX_REBOOT_MAGIC2B &&
731 magic2 != LINUX_REBOOT_MAGIC2C))
732 return -EINVAL;
733
734 /*
735 * If pid namespaces are enabled and the current task is in a child
736 * pid_namespace, the command is handled by reboot_pid_ns() which will
737 * call do_exit().
738 */
739 ret = reboot_pid_ns(pid_ns, cmd);
740 if (ret)
741 return ret;
742
743 /* Instead of trying to make the power_off code look like
744 * halt when pm_power_off is not set do it the easy way.
745 */
746 if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !kernel_can_power_off()) {
747 poweroff_fallback_to_halt = true;
748 cmd = LINUX_REBOOT_CMD_HALT;
749 }
750
751 mutex_lock(&system_transition_mutex);
752 switch (cmd) {
753 case LINUX_REBOOT_CMD_RESTART:
754 kernel_restart(NULL);
755 break;
756
757 case LINUX_REBOOT_CMD_CAD_ON:
758 C_A_D = 1;
759 break;
760
761 case LINUX_REBOOT_CMD_CAD_OFF:
762 C_A_D = 0;
763 break;
764
765 case LINUX_REBOOT_CMD_HALT:
766 kernel_halt();
767 do_exit(0);
768
769 case LINUX_REBOOT_CMD_POWER_OFF:
770 kernel_power_off();
771 do_exit(0);
772 break;
773
774 case LINUX_REBOOT_CMD_RESTART2:
775 ret = strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1);
776 if (ret < 0) {
777 ret = -EFAULT;
778 break;
779 }
780 buffer[sizeof(buffer) - 1] = '\0';
781
782 kernel_restart(buffer);
783 break;
784
785#ifdef CONFIG_KEXEC_CORE
786 case LINUX_REBOOT_CMD_KEXEC:
787 ret = kernel_kexec();
788 break;
789#endif
790
791#ifdef CONFIG_HIBERNATION
792 case LINUX_REBOOT_CMD_SW_SUSPEND:
793 ret = hibernate();
794 break;
795#endif
796
797 default:
798 ret = -EINVAL;
799 break;
800 }
801 mutex_unlock(&system_transition_mutex);
802 return ret;
803}
804
805static void deferred_cad(struct work_struct *dummy)
806{
807 kernel_restart(NULL);
808}
809
810/*
811 * This function gets called by ctrl-alt-del - ie the keyboard interrupt.
812 * As it's called within an interrupt, it may NOT sync: the only choice
813 * is whether to reboot at once, or just ignore the ctrl-alt-del.
814 */
815void ctrl_alt_del(void)
816{
817 static DECLARE_WORK(cad_work, deferred_cad);
818
819 if (C_A_D)
820 schedule_work(&cad_work);
821 else
822 kill_cad_pid(SIGINT, 1);
823}
824
825#define POWEROFF_CMD_PATH_LEN 256
826static char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";
827static const char reboot_cmd[] = "/sbin/reboot";
828
829static int run_cmd(const char *cmd)
830{
831 char **argv;
832 static char *envp[] = {
833 "HOME=/",
834 "PATH=/sbin:/bin:/usr/sbin:/usr/bin",
835 NULL
836 };
837 int ret;
838 argv = argv_split(GFP_KERNEL, cmd, NULL);
839 if (argv) {
840 ret = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_EXEC);
841 argv_free(argv);
842 } else {
843 ret = -ENOMEM;
844 }
845
846 return ret;
847}
848
849static int __orderly_reboot(void)
850{
851 int ret;
852
853 ret = run_cmd(reboot_cmd);
854
855 if (ret) {
856 pr_warn("Failed to start orderly reboot: forcing the issue\n");
857 emergency_sync();
858 kernel_restart(NULL);
859 }
860
861 return ret;
862}
863
864static int __orderly_poweroff(bool force)
865{
866 int ret;
867
868 ret = run_cmd(poweroff_cmd);
869
870 if (ret && force) {
871 pr_warn("Failed to start orderly shutdown: forcing the issue\n");
872
873 /*
874 * I guess this should try to kick off some daemon to sync and
875 * poweroff asap. Or not even bother syncing if we're doing an
876 * emergency shutdown?
877 */
878 emergency_sync();
879 kernel_power_off();
880 }
881
882 return ret;
883}
884
885static bool poweroff_force;
886
887static void poweroff_work_func(struct work_struct *work)
888{
889 __orderly_poweroff(poweroff_force);
890}
891
892static DECLARE_WORK(poweroff_work, poweroff_work_func);
893
894/**
895 * orderly_poweroff - Trigger an orderly system poweroff
896 * @force: force poweroff if command execution fails
897 *
898 * This may be called from any context to trigger a system shutdown.
899 * If the orderly shutdown fails, it will force an immediate shutdown.
900 */
901void orderly_poweroff(bool force)
902{
903 if (force) /* do not override the pending "true" */
904 poweroff_force = true;
905 schedule_work(&poweroff_work);
906}
907EXPORT_SYMBOL_GPL(orderly_poweroff);
908
909static void reboot_work_func(struct work_struct *work)
910{
911 __orderly_reboot();
912}
913
914static DECLARE_WORK(reboot_work, reboot_work_func);
915
916/**
917 * orderly_reboot - Trigger an orderly system reboot
918 *
919 * This may be called from any context to trigger a system reboot.
920 * If the orderly reboot fails, it will force an immediate reboot.
921 */
922void orderly_reboot(void)
923{
924 schedule_work(&reboot_work);
925}
926EXPORT_SYMBOL_GPL(orderly_reboot);
927
928/**
929 * hw_failure_emergency_poweroff_func - emergency poweroff work after a known delay
930 * @work: work_struct associated with the emergency poweroff function
931 *
932 * This function is called in very critical situations to force
933 * a kernel poweroff after a configurable timeout value.
934 */
935static void hw_failure_emergency_poweroff_func(struct work_struct *work)
936{
937 /*
938 * We have reached here after the emergency shutdown waiting period has
939 * expired. This means orderly_poweroff has not been able to shut off
940 * the system for some reason.
941 *
942 * Try to shut down the system immediately using kernel_power_off
943 * if populated
944 */
945 pr_emerg("Hardware protection timed-out. Trying forced poweroff\n");
946 kernel_power_off();
947
948 /*
949 * Worst of the worst case trigger emergency restart
950 */
951 pr_emerg("Hardware protection shutdown failed. Trying emergency restart\n");
952 emergency_restart();
953}
954
955static DECLARE_DELAYED_WORK(hw_failure_emergency_poweroff_work,
956 hw_failure_emergency_poweroff_func);
957
958/**
959 * hw_failure_emergency_poweroff - Trigger an emergency system poweroff
960 *
961 * This may be called from any critical situation to trigger a system shutdown
962 * after a given period of time. If time is negative this is not scheduled.
963 */
964static void hw_failure_emergency_poweroff(int poweroff_delay_ms)
965{
966 if (poweroff_delay_ms <= 0)
967 return;
968 schedule_delayed_work(&hw_failure_emergency_poweroff_work,
969 msecs_to_jiffies(poweroff_delay_ms));
970}
971
972/**
973 * __hw_protection_shutdown - Trigger an emergency system shutdown or reboot
974 *
975 * @reason: Reason of emergency shutdown or reboot to be printed.
976 * @ms_until_forced: Time to wait for orderly shutdown or reboot before
977 * triggering it. Negative value disables the forced
978 * shutdown or reboot.
979 * @shutdown: If true, indicates that a shutdown will happen
980 * after the critical tempeature is reached.
981 * If false, indicates that a reboot will happen
982 * after the critical tempeature is reached.
983 *
984 * Initiate an emergency system shutdown or reboot in order to protect
985 * hardware from further damage. Usage examples include a thermal protection.
986 * NOTE: The request is ignored if protection shutdown or reboot is already
987 * pending even if the previous request has given a large timeout for forced
988 * shutdown/reboot.
989 */
990void __hw_protection_shutdown(const char *reason, int ms_until_forced, bool shutdown)
991{
992 static atomic_t allow_proceed = ATOMIC_INIT(1);
993
994 pr_emerg("HARDWARE PROTECTION shutdown (%s)\n", reason);
995
996 /* Shutdown should be initiated only once. */
997 if (!atomic_dec_and_test(&allow_proceed))
998 return;
999
1000 /*
1001 * Queue a backup emergency shutdown in the event of
1002 * orderly_poweroff failure
1003 */
1004 hw_failure_emergency_poweroff(ms_until_forced);
1005 if (shutdown)
1006 orderly_poweroff(true);
1007 else
1008 orderly_reboot();
1009}
1010EXPORT_SYMBOL_GPL(__hw_protection_shutdown);
1011
1012static int __init reboot_setup(char *str)
1013{
1014 for (;;) {
1015 enum reboot_mode *mode;
1016
1017 /*
1018 * Having anything passed on the command line via
1019 * reboot= will cause us to disable DMI checking
1020 * below.
1021 */
1022 reboot_default = 0;
1023
1024 if (!strncmp(str, "panic_", 6)) {
1025 mode = &panic_reboot_mode;
1026 str += 6;
1027 } else {
1028 mode = &reboot_mode;
1029 }
1030
1031 switch (*str) {
1032 case 'w':
1033 *mode = REBOOT_WARM;
1034 break;
1035
1036 case 'c':
1037 *mode = REBOOT_COLD;
1038 break;
1039
1040 case 'h':
1041 *mode = REBOOT_HARD;
1042 break;
1043
1044 case 's':
1045 /*
1046 * reboot_cpu is s[mp]#### with #### being the processor
1047 * to be used for rebooting. Skip 's' or 'smp' prefix.
1048 */
1049 str += str[1] == 'm' && str[2] == 'p' ? 3 : 1;
1050
1051 if (isdigit(str[0])) {
1052 int cpu = simple_strtoul(str, NULL, 0);
1053
1054 if (cpu >= num_possible_cpus()) {
1055 pr_err("Ignoring the CPU number in reboot= option. "
1056 "CPU %d exceeds possible cpu number %d\n",
1057 cpu, num_possible_cpus());
1058 break;
1059 }
1060 reboot_cpu = cpu;
1061 } else
1062 *mode = REBOOT_SOFT;
1063 break;
1064
1065 case 'g':
1066 *mode = REBOOT_GPIO;
1067 break;
1068
1069 case 'b':
1070 case 'a':
1071 case 'k':
1072 case 't':
1073 case 'e':
1074 case 'p':
1075 reboot_type = *str;
1076 break;
1077
1078 case 'f':
1079 reboot_force = 1;
1080 break;
1081 }
1082
1083 str = strchr(str, ',');
1084 if (str)
1085 str++;
1086 else
1087 break;
1088 }
1089 return 1;
1090}
1091__setup("reboot=", reboot_setup);
1092
1093#ifdef CONFIG_SYSFS
1094
1095#define REBOOT_COLD_STR "cold"
1096#define REBOOT_WARM_STR "warm"
1097#define REBOOT_HARD_STR "hard"
1098#define REBOOT_SOFT_STR "soft"
1099#define REBOOT_GPIO_STR "gpio"
1100#define REBOOT_UNDEFINED_STR "undefined"
1101
1102#define BOOT_TRIPLE_STR "triple"
1103#define BOOT_KBD_STR "kbd"
1104#define BOOT_BIOS_STR "bios"
1105#define BOOT_ACPI_STR "acpi"
1106#define BOOT_EFI_STR "efi"
1107#define BOOT_PCI_STR "pci"
1108
1109static ssize_t mode_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
1110{
1111 const char *val;
1112
1113 switch (reboot_mode) {
1114 case REBOOT_COLD:
1115 val = REBOOT_COLD_STR;
1116 break;
1117 case REBOOT_WARM:
1118 val = REBOOT_WARM_STR;
1119 break;
1120 case REBOOT_HARD:
1121 val = REBOOT_HARD_STR;
1122 break;
1123 case REBOOT_SOFT:
1124 val = REBOOT_SOFT_STR;
1125 break;
1126 case REBOOT_GPIO:
1127 val = REBOOT_GPIO_STR;
1128 break;
1129 default:
1130 val = REBOOT_UNDEFINED_STR;
1131 }
1132
1133 return sprintf(buf, "%s\n", val);
1134}
1135static ssize_t mode_store(struct kobject *kobj, struct kobj_attribute *attr,
1136 const char *buf, size_t count)
1137{
1138 if (!capable(CAP_SYS_BOOT))
1139 return -EPERM;
1140
1141 if (!strncmp(buf, REBOOT_COLD_STR, strlen(REBOOT_COLD_STR)))
1142 reboot_mode = REBOOT_COLD;
1143 else if (!strncmp(buf, REBOOT_WARM_STR, strlen(REBOOT_WARM_STR)))
1144 reboot_mode = REBOOT_WARM;
1145 else if (!strncmp(buf, REBOOT_HARD_STR, strlen(REBOOT_HARD_STR)))
1146 reboot_mode = REBOOT_HARD;
1147 else if (!strncmp(buf, REBOOT_SOFT_STR, strlen(REBOOT_SOFT_STR)))
1148 reboot_mode = REBOOT_SOFT;
1149 else if (!strncmp(buf, REBOOT_GPIO_STR, strlen(REBOOT_GPIO_STR)))
1150 reboot_mode = REBOOT_GPIO;
1151 else
1152 return -EINVAL;
1153
1154 reboot_default = 0;
1155
1156 return count;
1157}
1158static struct kobj_attribute reboot_mode_attr = __ATTR_RW(mode);
1159
1160#ifdef CONFIG_X86
1161static ssize_t force_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
1162{
1163 return sprintf(buf, "%d\n", reboot_force);
1164}
1165static ssize_t force_store(struct kobject *kobj, struct kobj_attribute *attr,
1166 const char *buf, size_t count)
1167{
1168 bool res;
1169
1170 if (!capable(CAP_SYS_BOOT))
1171 return -EPERM;
1172
1173 if (kstrtobool(buf, &res))
1174 return -EINVAL;
1175
1176 reboot_default = 0;
1177 reboot_force = res;
1178
1179 return count;
1180}
1181static struct kobj_attribute reboot_force_attr = __ATTR_RW(force);
1182
1183static ssize_t type_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
1184{
1185 const char *val;
1186
1187 switch (reboot_type) {
1188 case BOOT_TRIPLE:
1189 val = BOOT_TRIPLE_STR;
1190 break;
1191 case BOOT_KBD:
1192 val = BOOT_KBD_STR;
1193 break;
1194 case BOOT_BIOS:
1195 val = BOOT_BIOS_STR;
1196 break;
1197 case BOOT_ACPI:
1198 val = BOOT_ACPI_STR;
1199 break;
1200 case BOOT_EFI:
1201 val = BOOT_EFI_STR;
1202 break;
1203 case BOOT_CF9_FORCE:
1204 val = BOOT_PCI_STR;
1205 break;
1206 default:
1207 val = REBOOT_UNDEFINED_STR;
1208 }
1209
1210 return sprintf(buf, "%s\n", val);
1211}
1212static ssize_t type_store(struct kobject *kobj, struct kobj_attribute *attr,
1213 const char *buf, size_t count)
1214{
1215 if (!capable(CAP_SYS_BOOT))
1216 return -EPERM;
1217
1218 if (!strncmp(buf, BOOT_TRIPLE_STR, strlen(BOOT_TRIPLE_STR)))
1219 reboot_type = BOOT_TRIPLE;
1220 else if (!strncmp(buf, BOOT_KBD_STR, strlen(BOOT_KBD_STR)))
1221 reboot_type = BOOT_KBD;
1222 else if (!strncmp(buf, BOOT_BIOS_STR, strlen(BOOT_BIOS_STR)))
1223 reboot_type = BOOT_BIOS;
1224 else if (!strncmp(buf, BOOT_ACPI_STR, strlen(BOOT_ACPI_STR)))
1225 reboot_type = BOOT_ACPI;
1226 else if (!strncmp(buf, BOOT_EFI_STR, strlen(BOOT_EFI_STR)))
1227 reboot_type = BOOT_EFI;
1228 else if (!strncmp(buf, BOOT_PCI_STR, strlen(BOOT_PCI_STR)))
1229 reboot_type = BOOT_CF9_FORCE;
1230 else
1231 return -EINVAL;
1232
1233 reboot_default = 0;
1234
1235 return count;
1236}
1237static struct kobj_attribute reboot_type_attr = __ATTR_RW(type);
1238#endif
1239
1240#ifdef CONFIG_SMP
1241static ssize_t cpu_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
1242{
1243 return sprintf(buf, "%d\n", reboot_cpu);
1244}
1245static ssize_t cpu_store(struct kobject *kobj, struct kobj_attribute *attr,
1246 const char *buf, size_t count)
1247{
1248 unsigned int cpunum;
1249 int rc;
1250
1251 if (!capable(CAP_SYS_BOOT))
1252 return -EPERM;
1253
1254 rc = kstrtouint(buf, 0, &cpunum);
1255
1256 if (rc)
1257 return rc;
1258
1259 if (cpunum >= num_possible_cpus())
1260 return -ERANGE;
1261
1262 reboot_default = 0;
1263 reboot_cpu = cpunum;
1264
1265 return count;
1266}
1267static struct kobj_attribute reboot_cpu_attr = __ATTR_RW(cpu);
1268#endif
1269
1270static struct attribute *reboot_attrs[] = {
1271 &reboot_mode_attr.attr,
1272#ifdef CONFIG_X86
1273 &reboot_force_attr.attr,
1274 &reboot_type_attr.attr,
1275#endif
1276#ifdef CONFIG_SMP
1277 &reboot_cpu_attr.attr,
1278#endif
1279 NULL,
1280};
1281
1282#ifdef CONFIG_SYSCTL
1283static struct ctl_table kern_reboot_table[] = {
1284 {
1285 .procname = "poweroff_cmd",
1286 .data = &poweroff_cmd,
1287 .maxlen = POWEROFF_CMD_PATH_LEN,
1288 .mode = 0644,
1289 .proc_handler = proc_dostring,
1290 },
1291 {
1292 .procname = "ctrl-alt-del",
1293 .data = &C_A_D,
1294 .maxlen = sizeof(int),
1295 .mode = 0644,
1296 .proc_handler = proc_dointvec,
1297 },
1298 { }
1299};
1300
1301static void __init kernel_reboot_sysctls_init(void)
1302{
1303 register_sysctl_init("kernel", kern_reboot_table);
1304}
1305#else
1306#define kernel_reboot_sysctls_init() do { } while (0)
1307#endif /* CONFIG_SYSCTL */
1308
1309static const struct attribute_group reboot_attr_group = {
1310 .attrs = reboot_attrs,
1311};
1312
1313static int __init reboot_ksysfs_init(void)
1314{
1315 struct kobject *reboot_kobj;
1316 int ret;
1317
1318 reboot_kobj = kobject_create_and_add("reboot", kernel_kobj);
1319 if (!reboot_kobj)
1320 return -ENOMEM;
1321
1322 ret = sysfs_create_group(reboot_kobj, &reboot_attr_group);
1323 if (ret) {
1324 kobject_put(reboot_kobj);
1325 return ret;
1326 }
1327
1328 kernel_reboot_sysctls_init();
1329
1330 return 0;
1331}
1332late_initcall(reboot_ksysfs_init);
1333
1334#endif