path: root/kernel/reboot.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;

static enum hw_protection_action hw_protection_action = HWPROT_ACT_SHUTDOWN;

/*
 * 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;
	struct device *dev;
};

/*
 * This variable is used to indicate if a halt was initiated instead of a
 * reboot when the reboot call was invoked with LINUX_REBOOT_CMD_POWER_OFF, but
 * the system cannot be powered off. This allowes kernel_halt() to notify users
 * of that.
 */
static bool poweroff_fallback_to_halt;

/*
 * 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);

/*
 *	Notifier list for kernel code which wants to be called
 *	at shutdown. This is used to stop any idling DMA operations
 *	and the like.
 */
static BLOCKING_NOTIFIER_HEAD(reboot_notifier_list);

/**
 *	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);
	system_state = SYSTEM_RESTART;
	machine_emergency_restart();
}
EXPORT_SYMBOL_GPL(emergency_restart);

void