linux-stable/kernel/reboot.c
Linus Torvalds 93d17c1c8c printk fixes for 5.19-rc3
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Merge tag 'printk-for-5.19-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux

Pull printk fixes from Petr Mladek:
 "Make the global console_sem available for CPU that is handling panic()
  or shutdown.

  This is an old problem when an existing console lock owner might block
  console output, but it became more visible with the kthreads"

* tag 'printk-for-5.19-rc3' of git://git.kernel.org/pub/scm/linux/kernel/git/printk/linux:
  printk: Wait for the global console lock when the system is going down
  printk: Block console kthreads when direct printing will be required
2022-06-17 14:57:42 -05:00

1308 lines
32 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* linux/kernel/reboot.c
*
* Copyright (C) 2013 Linus Torvalds
*/
#define pr_fmt(fmt) "reboot: " fmt
#include <linux/atomic.h>
#include <linux/ctype.h>
#include <linux/export.h>
#include <linux/kexec.h>
#include <linux/kmod.h>
#include <linux/kmsg_dump.h>
#include <linux/reboot.h>
#include <linux/suspend.h>
#include <linux/syscalls.h>
#include <linux/syscore_ops.h>
#include <linux/uaccess.h>
/*
* this indicates whether you can reboot with ctrl-alt-del: the default is yes
*/
static int C_A_D = 1;
struct pid *cad_pid;
EXPORT_SYMBOL(cad_pid);
#if defined(CONFIG_ARM)
#define DEFAULT_REBOOT_MODE = REBOOT_HARD
#else
#define DEFAULT_REBOOT_MODE
#endif
enum reboot_mode reboot_mode DEFAULT_REBOOT_MODE;
EXPORT_SYMBOL_GPL(reboot_mode);
enum reboot_mode panic_reboot_mode = REBOOT_UNDEFINED;
/*
* This variable is used privately to keep track of whether or not
* reboot_type is still set to its default value (i.e., reboot= hasn't
* been set on the command line). This is needed so that we can
* suppress DMI scanning for reboot quirks. Without it, it's
* impossible to override a faulty reboot quirk without recompiling.
*/
int reboot_default = 1;
int reboot_cpu;
enum reboot_type reboot_type = BOOT_ACPI;
int reboot_force;
struct sys_off_handler {
struct notifier_block nb;
int (*sys_off_cb)(struct sys_off_data *data);
void *cb_data;
enum sys_off_mode mode;
bool blocking;
void *list;
};
/*
* Temporary stub that prevents linkage failure while we're in process
* of removing all uses of legacy pm_power_off() around the kernel.
*/
void __weak (*pm_power_off)(void);
/**
* emergency_restart - reboot the system
*
* Without shutting down any hardware or taking any locks
* reboot the system. This is called when we know we are in
* trouble so this is our best effort to reboot. This is
* safe to call in interrupt context.
*/
void emergency_restart(void)
{
kmsg_dump(KMSG_DUMP_EMERG);
machine_emergency_restart();
}
EXPORT_SYMBOL_GPL(emergency_restart);
void kernel_restart_prepare(char *cmd)
{
blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd);
system_state = SYSTEM_RESTART;
try_block_console_kthreads(10000);
usermodehelper_disable();
device_shutdown();
}
/**
* register_reboot_notifier - Register function to be called at reboot time
* @nb: Info about notifier function to be called
*
* Registers a function with the list of functions
* to be called at reboot time.
*
* Currently always returns zero, as blocking_notifier_chain_register()
* always returns zero.
*/
int register_reboot_notifier(struct notifier_block *nb)
{
return blocking_notifier_chain_register(&reboot_notifier_list, nb);
}
EXPORT_SYMBOL(register_reboot_notifier);
/**
* unregister_reboot_notifier - Unregister previously registered reboot notifier
* @nb: Hook to be unregistered
*
* Unregisters a previously registered reboot
* notifier function.
*
* Returns zero on success, or %-ENOENT on failure.
*/
int unregister_reboot_notifier(struct notifier_block *nb)
{
return blocking_notifier_chain_unregister(&reboot_notifier_list, nb);
}
EXPORT_SYMBOL(unregister_reboot_notifier);
static void devm_unregister_reboot_notifier(struct device *dev, void *res)
{
WARN_ON(unregister_reboot_notifier(*(struct notifier_block **)res));
}
int devm_register_reboot_notifier(struct device *dev, struct notifier_block *nb)
{
struct notifier_block **rcnb;
int ret;
rcnb = devres_alloc(devm_unregister_reboot_notifier,
sizeof(*rcnb), GFP_KERNEL);
if (!rcnb)
return -ENOMEM;
ret = register_reboot_notifier(nb);
if (!ret) {
*rcnb = nb;
devres_add(dev, rcnb);
} else {
devres_free(rcnb);
}
return ret;
}
EXPORT_SYMBOL(devm_register_reboot_notifier);
/*
* Notifier list for kernel code which wants to be called
* to restart the system.
*/
static ATOMIC_NOTIFIER_HEAD(restart_handler_list);
/**
* register_restart_handler - Register function to be called to reset
* the system
* @nb: Info about handler function to be called
* @nb->priority: Handler priority. Handlers should follow the
* following guidelines for setting priorities.
* 0: Restart handler of last resort,
* with limited restart capabilities
* 128: Default restart handler; use if no other
* restart handler is expected to be available,
* and/or if restart functionality is
* sufficient to restart the entire system
* 255: Highest priority restart handler, will
* preempt all other restart handlers
*
* Registers a function with code to be called to restart the
* system.
*
* Registered functions will be called from machine_restart as last
* step of the restart sequence (if the architecture specific
* machine_restart function calls do_kernel_restart - see below
* for details).
* Registered functions are expected to restart the system immediately.
* If more than one function is registered, the restart handler priority
* selects which function will be called first.
*
* Restart handlers are expected to be registered from non-architecture
* code, typically from drivers. A typical use case would be a system
* where restart functionality is provided through a watchdog. Multiple
* restart handlers may exist; for example, one restart handler might
* restart the entire system, while another only restarts the CPU.
* In such cases, the restart handler which only restarts part of the
* hardware is expected to register with low priority to ensure that
* it only runs if no other means to restart the system is available.
*
* Currently always returns zero, as atomic_notifier_chain_register()
* always returns zero.
*/
int register_restart_handler(struct notifier_block *nb)
{
return atomic_notifier_chain_register(&restart_handler_list, nb);
}
EXPORT_SYMBOL(register_restart_handler);
/**
* unregister_restart_handler - Unregister previously registered
* restart handler
* @nb: Hook to be unregistered
*
* Unregisters a previously registered restart handler function.
*
* Returns zero on success, or %-ENOENT on failure.
*/
int unregister_restart_handler(struct notifier_block *nb)
{
return atomic_notifier_chain_unregister(&restart_handler_list, nb);
}
EXPORT_SYMBOL(unregister_restart_handler);
/**
* do_kernel_restart - Execute kernel restart handler call chain
*
* Calls functions registered with register_restart_handler.
*
* Expected to be called from machine_restart as last step of the restart
* sequence.
*
* Restarts the system immediately if a restart handler function has been
* registered. Otherwise does nothing.
*/
void do_kernel_restart(char *cmd)
{
atomic_notifier_call_chain(&restart_handler_list, reboot_mode, cmd);
}
void migrate_to_reboot_cpu(void)
{
/* The boot cpu is always logical cpu 0 */
int cpu = reboot_cpu;
cpu_hotplug_disable();
/* Make certain the cpu I'm about to reboot on is online */
if (!cpu_online(cpu))
cpu = cpumask_first(cpu_online_mask);
/* Prevent races with other tasks migrating this task */
current->flags |= PF_NO_SETAFFINITY;
/* Make certain I only run on the appropriate processor */
set_cpus_allowed_ptr(current, cpumask_of(cpu));
}
/**
* kernel_restart - reboot the system
* @cmd: pointer to buffer containing command to execute for restart
* or %NULL
*
* Shutdown everything and perform a clean reboot.
* This is not safe to call in interrupt context.
*/
void kernel_restart(char *cmd)
{
kernel_restart_prepare(cmd);
migrate_to_reboot_cpu();
syscore_shutdown();
if (!cmd)
pr_emerg("Restarting system\n");
else
pr_emerg("Restarting system with command '%s'\n", cmd);
kmsg_dump(KMSG_DUMP_SHUTDOWN);
machine_restart(cmd);
}
EXPORT_SYMBOL_GPL(kernel_restart);
static void kernel_shutdown_prepare(enum system_states state)
{
blocking_notifier_call_chain(&reboot_notifier_list,
(state == SYSTEM_HALT) ? SYS_HALT : SYS_POWER_OFF, NULL);
system_state = state;
try_block_console_kthreads(10000);
usermodehelper_disable();
device_shutdown();
}
/**
* kernel_halt - halt the system
*
* Shutdown everything and perform a clean system halt.
*/
void kernel_halt(void)
{
kernel_shutdown_prepare(SYSTEM_HALT);
migrate_to_reboot_cpu();
syscore_shutdown();
pr_emerg("System halted\n");
kmsg_dump(KMSG_DUMP_SHUTDOWN);
machine_halt();
}
EXPORT_SYMBOL_GPL(kernel_halt);
/*
* Notifier list for kernel code which wants to be called
* to prepare system for power off.
*/
static BLOCKING_NOTIFIER_HEAD(power_off_prep_handler_list);
/*
* Notifier list for kernel code which wants to be called
* to power off system.
*/
static ATOMIC_NOTIFIER_HEAD(power_off_handler_list);
static int sys_off_notify(struct notifier_block *nb,
unsigned long mode, void *cmd)
{
struct sys_off_handler *handler;
struct sys_off_data data = {};
handler = container_of(nb, struct sys_off_handler, nb);
data.cb_data = handler->cb_data;
data.mode = mode;
data.cmd = cmd;
return handler->sys_off_cb(&data);
}
static struct sys_off_handler platform_sys_off_handler;
static struct sys_off_handler *alloc_sys_off_handler(int priority)
{
struct sys_off_handler *handler;
gfp_t flags;
/*
* Platforms like m68k can't allocate sys_off handler dynamically
* at the early boot time because memory allocator isn't available yet.
*/
if (priority == SYS_OFF_PRIO_PLATFORM) {
handler = &platform_sys_off_handler;
if (handler->cb_data)
return ERR_PTR(-EBUSY);
} else {
if (system_state > SYSTEM_RUNNING)
flags = GFP_ATOMIC;
else
flags = GFP_KERNEL;
handler = kzalloc(sizeof(*handler), flags);
if (!handler)
return ERR_PTR(-ENOMEM);
}
return handler;
}
static void free_sys_off_handler(struct sys_off_handler *handler)
{
if (handler == &platform_sys_off_handler)
memset(handler, 0, sizeof(*handler));
else
kfree(handler);
}
/**
* register_sys_off_handler - Register sys-off handler
* @mode: Sys-off mode
* @priority: Handler priority
* @callback: Callback function
* @cb_data: Callback argument
*
* Registers system power-off or restart handler that will be invoked
* at the step corresponding to the given sys-off mode. Handler's callback
* should return NOTIFY_DONE to permit execution of the next handler in
* the call chain or NOTIFY_STOP to break the chain (in error case for
* example).
*
* Multiple handlers can be registered at the default priority level.
*
* Only one handler can be registered at the non-default priority level,
* otherwise ERR_PTR(-EBUSY) is returned.
*
* Returns a new instance of struct sys_off_handler on success, or
* an ERR_PTR()-encoded error code otherwise.
*/
struct sys_off_handler *
register_sys_off_handler(enum sys_off_mode mode,
int priority,
int (*callback)(struct sys_off_data *data),
void *cb_data)
{
struct sys_off_handler *handler;
int err;
handler = alloc_sys_off_handler(priority);
if (IS_ERR(handler))
return handler;
switch (mode) {
case SYS_OFF_MODE_POWER_OFF_PREPARE:
handler->list = &power_off_prep_handler_list;
handler->blocking = true;
break;
case SYS_OFF_MODE_POWER_OFF:
handler->list = &power_off_handler_list;
break;
case SYS_OFF_MODE_RESTART:
handler->list = &restart_handler_list;
break;
default:
free_sys_off_handler(handler);
return ERR_PTR(-EINVAL);
}
handler->nb.notifier_call = sys_off_notify;
handler->nb.priority = priority;
handler->sys_off_cb = callback;
handler->cb_data = cb_data;
handler->mode = mode;
if (handler->blocking) {
if (priority == SYS_OFF_PRIO_DEFAULT)
err = blocking_notifier_chain_register(handler->list,
&handler->nb);
else
err = blocking_notifier_chain_register_unique_prio(handler->list,
&handler->nb);
} else {
if (priority == SYS_OFF_PRIO_DEFAULT)
err = atomic_notifier_chain_register(handler->list,
&handler->nb);
else
err = atomic_notifier_chain_register_unique_prio(handler->list,
&handler->nb);
}
if (err) {
free_sys_off_handler(handler);
return ERR_PTR(err);
}
return handler;
}
EXPORT_SYMBOL_GPL(register_sys_off_handler);
/**
* unregister_sys_off_handler - Unregister sys-off handler
* @handler: Sys-off handler
*
* Unregisters given sys-off handler.
*/
void unregister_sys_off_handler(struct sys_off_handler *handler)
{
int err;
if (IS_ERR_OR_NULL(handler))
return;
if (handler->blocking)
err = blocking_notifier_chain_unregister(handler->list,
&handler->nb);
else
err = atomic_notifier_chain_unregister(handler->list,
&handler->nb);
/* sanity check, shall never happen */
WARN_ON(err);
free_sys_off_handler(handler);
}
EXPORT_SYMBOL_GPL(unregister_sys_off_handler);
static void devm_unregister_sys_off_handler(void *data)
{
struct sys_off_handler *handler = data;
unregister_sys_off_handler(handler);
}
/**
* devm_register_sys_off_handler - Register sys-off handler
* @dev: Device that registers handler
* @mode: Sys-off mode
* @priority: Handler priority
* @callback: Callback function
* @cb_data: Callback argument
*
* Registers resource-managed sys-off handler.
*
* Returns zero on success, or error code on failure.
*/
int devm_register_sys_off_handler(struct device *dev,
enum sys_off_mode mode,
int priority,
int (*callback)(struct sys_off_data *data),
void *cb_data)
{
struct sys_off_handler *handler;
handler = register_sys_off_handler(mode, priority, callback, cb_data);
if (IS_ERR(handler))
return PTR_ERR(handler);
return devm_add_action_or_reset(dev, devm_unregister_sys_off_handler,
handler);
}
EXPORT_SYMBOL_GPL(devm_register_sys_off_handler);
/**
* devm_register_power_off_handler - Register power-off handler
* @dev: Device that registers callback
* @callback: Callback function
* @cb_data: Callback's argument
*
* Registers resource-managed sys-off handler with a default priority
* and using power-off mode.
*
* Returns zero on success, or error code on failure.
*/
int devm_register_power_off_handler(struct device *dev,
int (*callback)(struct sys_off_data *data),
void *cb_data)
{
return devm_register_sys_off_handler(dev,
SYS_OFF_MODE_POWER_OFF,
SYS_OFF_PRIO_DEFAULT,
callback, cb_data);
}
EXPORT_SYMBOL_GPL(devm_register_power_off_handler);
/**
* devm_register_restart_handler - Register restart handler
* @dev: Device that registers callback
* @callback: Callback function
* @cb_data: Callback's argument
*
* Registers resource-managed sys-off handler with a default priority
* and using restart mode.
*
* Returns zero on success, or error code on failure.
*/
int devm_register_restart_handler(struct device *dev,
int (*callback)(struct sys_off_data *data),
void *cb_data)
{
return devm_register_sys_off_handler(dev,
SYS_OFF_MODE_RESTART,
SYS_OFF_PRIO_DEFAULT,
callback, cb_data);
}
EXPORT_SYMBOL_GPL(devm_register_restart_handler);
static struct sys_off_handler *platform_power_off_handler;
static int platform_power_off_notify(struct sys_off_data *data)
{
void (*platform_power_power_off_cb)(void) = data->cb_data;
platform_power_power_off_cb();
return NOTIFY_DONE;
}
/**
* register_platform_power_off - Register platform-level power-off callback
* @power_off: Power-off callback
*
* Registers power-off callback that will be called as last step
* of the power-off sequence. This callback is expected to be invoked
* for the last resort. Only one platform power-off callback is allowed
* to be registered at a time.
*
* Returns zero on success, or error code on failure.
*/
int register_platform_power_off(void (*power_off)(void))
{
struct sys_off_handler *handler;
handler = register_sys_off_handler(SYS_OFF_MODE_POWER_OFF,
SYS_OFF_PRIO_PLATFORM,
platform_power_off_notify,
power_off);
if (IS_ERR(handler))
return PTR_ERR(handler);
platform_power_off_handler = handler;
return 0;
}
EXPORT_SYMBOL_GPL(register_platform_power_off);
/**
* unregister_platform_power_off - Unregister platform-level power-off callback
* @power_off: Power-off callback
*
* Unregisters previously registered platform power-off callback.
*/
void unregister_platform_power_off(void (*power_off)(void))
{
if (platform_power_off_handler &&
platform_power_off_handler->cb_data == power_off) {
unregister_sys_off_handler(platform_power_off_handler);
platform_power_off_handler = NULL;
}
}
EXPORT_SYMBOL_GPL(unregister_platform_power_off);
static int legacy_pm_power_off(struct sys_off_data *data)
{
if (pm_power_off)
pm_power_off();
return NOTIFY_DONE;
}
static void do_kernel_power_off_prepare(void)
{
blocking_notifier_call_chain(&power_off_prep_handler_list, 0, NULL);
}
/**
* do_kernel_power_off - Execute kernel power-off handler call chain
*
* Expected to be called as last step of the power-off sequence.
*
* Powers off the system immediately if a power-off handler function has
* been registered. Otherwise does nothing.
*/
void do_kernel_power_off(void)
{
struct sys_off_handler *sys_off = NULL;
/*
* Register sys-off handlers for legacy PM callback. This allows
* legacy PM callbacks temporary co-exist with the new sys-off API.
*
* TODO: Remove legacy handlers once all legacy PM users will be
* switched to the sys-off based APIs.
*/
if (pm_power_off)
sys_off = register_sys_off_handler(SYS_OFF_MODE_POWER_OFF,
SYS_OFF_PRIO_DEFAULT,
legacy_pm_power_off, NULL);
atomic_notifier_call_chain(&power_off_handler_list, 0, NULL);
unregister_sys_off_handler(sys_off);
}
/**
* kernel_can_power_off - check whether system can be powered off
*
* Returns true if power-off handler is registered and system can be
* powered off, false otherwise.
*/
bool kernel_can_power_off(void)
{
return !atomic_notifier_call_chain_is_empty(&power_off_handler_list) ||
pm_power_off;
}
EXPORT_SYMBOL_GPL(kernel_can_power_off);
/**
* kernel_power_off - power_off the system
*
* Shutdown everything and perform a clean system power_off.
*/
void kernel_power_off(void)
{
kernel_shutdown_prepare(SYSTEM_POWER_OFF);
do_kernel_power_off_prepare();
migrate_to_reboot_cpu();
syscore_shutdown();
pr_emerg("Power down\n");
kmsg_dump(KMSG_DUMP_SHUTDOWN);
machine_power_off();
}
EXPORT_SYMBOL_GPL(kernel_power_off);
DEFINE_MUTEX(system_transition_mutex);
/*
* Reboot system call: for obvious reasons only root may call it,
* and even root needs to set up some magic numbers in the registers
* so that some mistake won't make this reboot the whole machine.
* You can also set the meaning of the ctrl-alt-del-key here.
*
* reboot doesn't sync: do that yourself before calling this.
*/
SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd,
void __user *, arg)
{
struct pid_namespace *pid_ns = task_active_pid_ns(current);
char buffer[256];
int ret = 0;
/* We only trust the superuser with rebooting the system. */
if (!ns_capable(pid_ns->user_ns, CAP_SYS_BOOT))
return -EPERM;
/* For safety, we require "magic" arguments. */
if (magic1 != LINUX_REBOOT_MAGIC1 ||
(magic2 != LINUX_REBOOT_MAGIC2 &&
magic2 != LINUX_REBOOT_MAGIC2A &&
magic2 != LINUX_REBOOT_MAGIC2B &&
magic2 != LINUX_REBOOT_MAGIC2C))
return -EINVAL;
/*
* If pid namespaces are enabled and the current task is in a child
* pid_namespace, the command is handled by reboot_pid_ns() which will
* call do_exit().
*/
ret = reboot_pid_ns(pid_ns, cmd);
if (ret)
return ret;
/* Instead of trying to make the power_off code look like
* halt when pm_power_off is not set do it the easy way.
*/
if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !kernel_can_power_off())
cmd = LINUX_REBOOT_CMD_HALT;
mutex_lock(&system_transition_mutex);
switch (cmd) {
case LINUX_REBOOT_CMD_RESTART:
kernel_restart(NULL);
break;
case LINUX_REBOOT_CMD_CAD_ON:
C_A_D = 1;
break;
case LINUX_REBOOT_CMD_CAD_OFF:
C_A_D = 0;
break;
case LINUX_REBOOT_CMD_HALT:
kernel_halt();
do_exit(0);
case LINUX_REBOOT_CMD_POWER_OFF:
kernel_power_off();
do_exit(0);
break;
case LINUX_REBOOT_CMD_RESTART2:
ret = strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1);
if (ret < 0) {
ret = -EFAULT;
break;
}
buffer[sizeof(buffer) - 1] = '\0';
kernel_restart(buffer);
break;
#ifdef CONFIG_KEXEC_CORE
case LINUX_REBOOT_CMD_KEXEC:
ret = kernel_kexec();
break;
#endif
#ifdef CONFIG_HIBERNATION
case LINUX_REBOOT_CMD_SW_SUSPEND:
ret = hibernate();
break;
#endif
default:
ret = -EINVAL;
break;
}
mutex_unlock(&system_transition_mutex);
return ret;
}
static void deferred_cad(struct work_struct *dummy)
{
kernel_restart(NULL);
}
/*
* This function gets called by ctrl-alt-del - ie the keyboard interrupt.
* As it's called within an interrupt, it may NOT sync: the only choice
* is whether to reboot at once, or just ignore the ctrl-alt-del.
*/
void ctrl_alt_del(void)
{
static DECLARE_WORK(cad_work, deferred_cad);
if (C_A_D)
schedule_work(&cad_work);
else
kill_cad_pid(SIGINT, 1);
}
#define POWEROFF_CMD_PATH_LEN 256
static char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";
static const char reboot_cmd[] = "/sbin/reboot";
static int run_cmd(const char *cmd)
{
char **argv;
static char *envp[] = {
"HOME=/",
"PATH=/sbin:/bin:/usr/sbin:/usr/bin",
NULL
};
int ret;
argv = argv_split(GFP_KERNEL, cmd, NULL);
if (argv) {
ret = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_EXEC);
argv_free(argv);
} else {
ret = -ENOMEM;
}
return ret;
}
static int __orderly_reboot(void)
{
int ret;
ret = run_cmd(reboot_cmd);
if (ret) {
printk_prefer_direct_enter();
pr_warn("Failed to start orderly reboot: forcing the issue\n");
emergency_sync();
kernel_restart(NULL);
printk_prefer_direct_exit();
}
return ret;
}
static int __orderly_poweroff(bool force)
{
int ret;
ret = run_cmd(poweroff_cmd);
if (ret && force) {
printk_prefer_direct_enter();
pr_warn("Failed to start orderly shutdown: forcing the issue\n");
/*
* I guess this should try to kick off some daemon to sync and
* poweroff asap. Or not even bother syncing if we're doing an
* emergency shutdown?
*/
emergency_sync();
kernel_power_off();
printk_prefer_direct_exit();
}
return ret;
}
static bool poweroff_force;
static void poweroff_work_func(struct work_struct *work)
{
__orderly_poweroff(poweroff_force);
}
static DECLARE_WORK(poweroff_work, poweroff_work_func);
/**
* orderly_poweroff - Trigger an orderly system poweroff
* @force: force poweroff if command execution fails
*
* This may be called from any context to trigger a system shutdown.
* If the orderly shutdown fails, it will force an immediate shutdown.
*/
void orderly_poweroff(bool force)
{
if (force) /* do not override the pending "true" */
poweroff_force = true;
schedule_work(&poweroff_work);
}
EXPORT_SYMBOL_GPL(orderly_poweroff);
static void reboot_work_func(struct work_struct *work)
{
__orderly_reboot();
}
static DECLARE_WORK(reboot_work, reboot_work_func);
/**
* orderly_reboot - Trigger an orderly system reboot
*
* This may be called from any context to trigger a system reboot.
* If the orderly reboot fails, it will force an immediate reboot.
*/
void orderly_reboot(void)
{
schedule_work(&reboot_work);
}
EXPORT_SYMBOL_GPL(orderly_reboot);
/**
* hw_failure_emergency_poweroff_func - emergency poweroff work after a known delay
* @work: work_struct associated with the emergency poweroff function
*
* This function is called in very critical situations to force
* a kernel poweroff after a configurable timeout value.
*/
static void hw_failure_emergency_poweroff_func(struct work_struct *work)
{
printk_prefer_direct_enter();
/*
* We have reached here after the emergency shutdown waiting period has
* expired. This means orderly_poweroff has not been able to shut off
* the system for some reason.
*
* Try to shut down the system immediately using kernel_power_off
* if populated
*/
pr_emerg("Hardware protection timed-out. Trying forced poweroff\n");
kernel_power_off();
/*
* Worst of the worst case trigger emergency restart
*/
pr_emerg("Hardware protection shutdown failed. Trying emergency restart\n");
emergency_restart();
printk_prefer_direct_exit();
}
static DECLARE_DELAYED_WORK(hw_failure_emergency_poweroff_work,
hw_failure_emergency_poweroff_func);
/**
* hw_failure_emergency_poweroff - Trigger an emergency system poweroff
*
* This may be called from any critical situation to trigger a system shutdown
* after a given period of time. If time is negative this is not scheduled.
*/
static void hw_failure_emergency_poweroff(int poweroff_delay_ms)
{
if (poweroff_delay_ms <= 0)
return;
schedule_delayed_work(&hw_failure_emergency_poweroff_work,
msecs_to_jiffies(poweroff_delay_ms));
}
/**
* hw_protection_shutdown - Trigger an emergency system poweroff
*
* @reason: Reason of emergency shutdown to be printed.
* @ms_until_forced: Time to wait for orderly shutdown before tiggering a
* forced shudown. Negative value disables the forced
* shutdown.
*
* Initiate an emergency system shutdown in order to protect hardware from
* further damage. Usage examples include a thermal protection or a voltage or
* current regulator failures.
* NOTE: The request is ignored if protection shutdown is already pending even
* if the previous request has given a large timeout for forced shutdown.
* Can be called from any context.
*/
void hw_protection_shutdown(const char *reason, int ms_until_forced)
{
static atomic_t allow_proceed = ATOMIC_INIT(1);
printk_prefer_direct_enter();
pr_emerg("HARDWARE PROTECTION shutdown (%s)\n", reason);
/* Shutdown should be initiated only once. */
if (!atomic_dec_and_test(&allow_proceed))
goto out;
/*
* Queue a backup emergency shutdown in the event of
* orderly_poweroff failure
*/
hw_failure_emergency_poweroff(ms_until_forced);
orderly_poweroff(true);
out:
printk_prefer_direct_exit();
}
EXPORT_SYMBOL_GPL(hw_protection_shutdown);
static int __init reboot_setup(char *str)
{
for (;;) {
enum reboot_mode *mode;
/*
* Having anything passed on the command line via
* reboot= will cause us to disable DMI checking
* below.
*/
reboot_default = 0;
if (!strncmp(str, "panic_", 6)) {
mode = &panic_reboot_mode;
str += 6;
} else {
mode = &reboot_mode;
}
switch (*str) {
case 'w':
*mode = REBOOT_WARM;
break;
case 'c':
*mode = REBOOT_COLD;
break;
case 'h':
*mode = REBOOT_HARD;
break;
case 's':
/*
* reboot_cpu is s[mp]#### with #### being the processor
* to be used for rebooting. Skip 's' or 'smp' prefix.
*/
str += str[1] == 'm' && str[2] == 'p' ? 3 : 1;
if (isdigit(str[0])) {
int cpu = simple_strtoul(str, NULL, 0);
if (cpu >= num_possible_cpus()) {
pr_err("Ignoring the CPU number in reboot= option. "
"CPU %d exceeds possible cpu number %d\n",
cpu, num_possible_cpus());
break;
}
reboot_cpu = cpu;
} else
*mode = REBOOT_SOFT;
break;
case 'g':
*mode = REBOOT_GPIO;
break;
case 'b':
case 'a':
case 'k':
case 't':
case 'e':
case 'p':
reboot_type = *str;
break;
case 'f':
reboot_force = 1;
break;
}
str = strchr(str, ',');
if (str)
str++;
else
break;
}
return 1;
}
__setup("reboot=", reboot_setup);
#ifdef CONFIG_SYSFS
#define REBOOT_COLD_STR "cold"
#define REBOOT_WARM_STR "warm"
#define REBOOT_HARD_STR "hard"
#define REBOOT_SOFT_STR "soft"
#define REBOOT_GPIO_STR "gpio"
#define REBOOT_UNDEFINED_STR "undefined"
#define BOOT_TRIPLE_STR "triple"
#define BOOT_KBD_STR "kbd"
#define BOOT_BIOS_STR "bios"
#define BOOT_ACPI_STR "acpi"
#define BOOT_EFI_STR "efi"
#define BOOT_PCI_STR "pci"
static ssize_t mode_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
{
const char *val;
switch (reboot_mode) {
case REBOOT_COLD:
val = REBOOT_COLD_STR;
break;
case REBOOT_WARM:
val = REBOOT_WARM_STR;
break;
case REBOOT_HARD:
val = REBOOT_HARD_STR;
break;
case REBOOT_SOFT:
val = REBOOT_SOFT_STR;
break;
case REBOOT_GPIO:
val = REBOOT_GPIO_STR;
break;
default:
val = REBOOT_UNDEFINED_STR;
}
return sprintf(buf, "%s\n", val);
}
static ssize_t mode_store(struct kobject *kobj, struct kobj_attribute *attr,
const char *buf, size_t count)
{
if (!capable(CAP_SYS_BOOT))
return -EPERM;
if (!strncmp(buf, REBOOT_COLD_STR, strlen(REBOOT_COLD_STR)))
reboot_mode = REBOOT_COLD;
else if (!strncmp(buf, REBOOT_WARM_STR, strlen(REBOOT_WARM_STR)))
reboot_mode = REBOOT_WARM;
else if (!strncmp(buf, REBOOT_HARD_STR, strlen(REBOOT_HARD_STR)))
reboot_mode = REBOOT_HARD;
else if (!strncmp(buf, REBOOT_SOFT_STR, strlen(REBOOT_SOFT_STR)))
reboot_mode = REBOOT_SOFT;
else if (!strncmp(buf, REBOOT_GPIO_STR, strlen(REBOOT_GPIO_STR)))
reboot_mode = REBOOT_GPIO;
else
return -EINVAL;
reboot_default = 0;
return count;
}
static struct kobj_attribute reboot_mode_attr = __ATTR_RW(mode);
#ifdef CONFIG_X86
static ssize_t force_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
{
return sprintf(buf, "%d\n", reboot_force);
}
static ssize_t force_store(struct kobject *kobj, struct kobj_attribute *attr,
const char *buf, size_t count)
{
bool res;
if (!capable(CAP_SYS_BOOT))
return -EPERM;
if (kstrtobool(buf, &res))
return -EINVAL;
reboot_default = 0;
reboot_force = res;
return count;
}
static struct kobj_attribute reboot_force_attr = __ATTR_RW(force);
static ssize_t type_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
{
const char *val;
switch (reboot_type) {
case BOOT_TRIPLE:
val = BOOT_TRIPLE_STR;
break;
case BOOT_KBD:
val = BOOT_KBD_STR;
break;
case BOOT_BIOS:
val = BOOT_BIOS_STR;
break;
case BOOT_ACPI:
val = BOOT_ACPI_STR;
break;
case BOOT_EFI:
val = BOOT_EFI_STR;
break;
case BOOT_CF9_FORCE:
val = BOOT_PCI_STR;
break;
default:
val = REBOOT_UNDEFINED_STR;
}
return sprintf(buf, "%s\n", val);
}
static ssize_t type_store(struct kobject *kobj, struct kobj_attribute *attr,
const char *buf, size_t count)
{
if (!capable(CAP_SYS_BOOT))
return -EPERM;
if (!strncmp(buf, BOOT_TRIPLE_STR, strlen(BOOT_TRIPLE_STR)))
reboot_type = BOOT_TRIPLE;
else if (!strncmp(buf, BOOT_KBD_STR, strlen(BOOT_KBD_STR)))
reboot_type = BOOT_KBD;
else if (!strncmp(buf, BOOT_BIOS_STR, strlen(BOOT_BIOS_STR)))
reboot_type = BOOT_BIOS;
else if (!strncmp(buf, BOOT_ACPI_STR, strlen(BOOT_ACPI_STR)))
reboot_type = BOOT_ACPI;
else if (!strncmp(buf, BOOT_EFI_STR, strlen(BOOT_EFI_STR)))
reboot_type = BOOT_EFI;
else if (!strncmp(buf, BOOT_PCI_STR, strlen(BOOT_PCI_STR)))
reboot_type = BOOT_CF9_FORCE;
else
return -EINVAL;
reboot_default = 0;
return count;
}
static struct kobj_attribute reboot_type_attr = __ATTR_RW(type);
#endif
#ifdef CONFIG_SMP
static ssize_t cpu_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
{
return sprintf(buf, "%d\n", reboot_cpu);
}
static ssize_t cpu_store(struct kobject *kobj, struct kobj_attribute *attr,
const char *buf, size_t count)
{
unsigned int cpunum;
int rc;
if (!capable(CAP_SYS_BOOT))
return -EPERM;
rc = kstrtouint(buf, 0, &cpunum);
if (rc)
return rc;
if (cpunum >= num_possible_cpus())
return -ERANGE;
reboot_default = 0;
reboot_cpu = cpunum;
return count;
}
static struct kobj_attribute reboot_cpu_attr = __ATTR_RW(cpu);
#endif
static struct attribute *reboot_attrs[] = {
&reboot_mode_attr.attr,
#ifdef CONFIG_X86
&reboot_force_attr.attr,
&reboot_type_attr.attr,
#endif
#ifdef CONFIG_SMP
&reboot_cpu_attr.attr,
#endif
NULL,
};
#ifdef CONFIG_SYSCTL
static struct ctl_table kern_reboot_table[] = {
{
.procname = "poweroff_cmd",
.data = &poweroff_cmd,
.maxlen = POWEROFF_CMD_PATH_LEN,
.mode = 0644,
.proc_handler = proc_dostring,
},
{
.procname = "ctrl-alt-del",
.data = &C_A_D,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_dointvec,
},
{ }
};
static void __init kernel_reboot_sysctls_init(void)
{
register_sysctl_init("kernel", kern_reboot_table);
}
#else
#define kernel_reboot_sysctls_init() do { } while (0)
#endif /* CONFIG_SYSCTL */
static const struct attribute_group reboot_attr_group = {
.attrs = reboot_attrs,
};
static int __init reboot_ksysfs_init(void)
{
struct kobject *reboot_kobj;
int ret;
reboot_kobj = kobject_create_and_add("reboot", kernel_kobj);
if (!reboot_kobj)
return -ENOMEM;
ret = sysfs_create_group(reboot_kobj, &reboot_attr_group);
if (ret) {
kobject_put(reboot_kobj);
return ret;
}
kernel_reboot_sysctls_init();
return 0;
}
late_initcall(reboot_ksysfs_init);
#endif