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![Andrey Smirnov](/assets/img/avatar_default.png)
Add devm_* wrapper around register_reboot_notifier to simplify device specific reboot notifier registration/unregistration. [akpm@linux-foundation.org: move `struct device' forward decl to top-of-file] Link: http://lkml.kernel.org/r/20170320171753.1705-1-andrew.smirnov@gmail.com Signed-off-by: Andrey Smirnov <andrew.smirnov@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
584 lines
14 KiB
C
584 lines
14 KiB
C
/*
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* linux/kernel/reboot.c
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*
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* Copyright (C) 2013 Linus Torvalds
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*/
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#define pr_fmt(fmt) "reboot: " fmt
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#include <linux/ctype.h>
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#include <linux/export.h>
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#include <linux/kexec.h>
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#include <linux/kmod.h>
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#include <linux/kmsg_dump.h>
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#include <linux/reboot.h>
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#include <linux/suspend.h>
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#include <linux/syscalls.h>
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#include <linux/syscore_ops.h>
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#include <linux/uaccess.h>
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/*
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* this indicates whether you can reboot with ctrl-alt-del: the default is yes
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*/
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int C_A_D = 1;
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struct pid *cad_pid;
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EXPORT_SYMBOL(cad_pid);
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#if defined(CONFIG_ARM) || defined(CONFIG_UNICORE32)
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#define DEFAULT_REBOOT_MODE = REBOOT_HARD
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#else
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#define DEFAULT_REBOOT_MODE
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#endif
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enum reboot_mode reboot_mode DEFAULT_REBOOT_MODE;
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/*
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* This variable is used privately to keep track of whether or not
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* reboot_type is still set to its default value (i.e., reboot= hasn't
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* been set on the command line). This is needed so that we can
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* suppress DMI scanning for reboot quirks. Without it, it's
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* impossible to override a faulty reboot quirk without recompiling.
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*/
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int reboot_default = 1;
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int reboot_cpu;
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enum reboot_type reboot_type = BOOT_ACPI;
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int reboot_force;
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/*
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* If set, this is used for preparing the system to power off.
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*/
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void (*pm_power_off_prepare)(void);
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/**
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* emergency_restart - reboot the system
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*
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* Without shutting down any hardware or taking any locks
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* reboot the system. This is called when we know we are in
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* trouble so this is our best effort to reboot. This is
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* safe to call in interrupt context.
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*/
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void emergency_restart(void)
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{
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kmsg_dump(KMSG_DUMP_EMERG);
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machine_emergency_restart();
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}
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EXPORT_SYMBOL_GPL(emergency_restart);
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void kernel_restart_prepare(char *cmd)
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{
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blocking_notifier_call_chain(&reboot_notifier_list, SYS_RESTART, cmd);
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system_state = SYSTEM_RESTART;
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usermodehelper_disable();
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device_shutdown();
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}
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/**
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* register_reboot_notifier - Register function to be called at reboot time
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* @nb: Info about notifier function to be called
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*
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* Registers a function with the list of functions
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* to be called at reboot time.
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*
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* Currently always returns zero, as blocking_notifier_chain_register()
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* always returns zero.
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*/
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int register_reboot_notifier(struct notifier_block *nb)
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{
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return blocking_notifier_chain_register(&reboot_notifier_list, nb);
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}
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EXPORT_SYMBOL(register_reboot_notifier);
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/**
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* unregister_reboot_notifier - Unregister previously registered reboot notifier
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* @nb: Hook to be unregistered
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*
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* Unregisters a previously registered reboot
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* notifier function.
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*
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* Returns zero on success, or %-ENOENT on failure.
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*/
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int unregister_reboot_notifier(struct notifier_block *nb)
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{
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return blocking_notifier_chain_unregister(&reboot_notifier_list, nb);
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}
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EXPORT_SYMBOL(unregister_reboot_notifier);
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static void devm_unregister_reboot_notifier(struct device *dev, void *res)
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{
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WARN_ON(unregister_reboot_notifier(*(struct notifier_block **)res));
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}
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int devm_register_reboot_notifier(struct device *dev, struct notifier_block *nb)
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{
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struct notifier_block **rcnb;
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int ret;
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rcnb = devres_alloc(devm_unregister_reboot_notifier,
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sizeof(*rcnb), GFP_KERNEL);
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if (!rcnb)
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return -ENOMEM;
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ret = register_reboot_notifier(nb);
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if (!ret) {
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*rcnb = nb;
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devres_add(dev, rcnb);
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} else {
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devres_free(rcnb);
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}
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return ret;
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}
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EXPORT_SYMBOL(devm_register_reboot_notifier);
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/*
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* Notifier list for kernel code which wants to be called
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* to restart the system.
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*/
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static ATOMIC_NOTIFIER_HEAD(restart_handler_list);
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/**
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* register_restart_handler - Register function to be called to reset
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* the system
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* @nb: Info about handler function to be called
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* @nb->priority: Handler priority. Handlers should follow the
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* following guidelines for setting priorities.
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* 0: Restart handler of last resort,
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* with limited restart capabilities
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* 128: Default restart handler; use if no other
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* restart handler is expected to be available,
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* and/or if restart functionality is
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* sufficient to restart the entire system
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* 255: Highest priority restart handler, will
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* preempt all other restart handlers
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*
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* Registers a function with code to be called to restart the
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* system.
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*
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* Registered functions will be called from machine_restart as last
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* step of the restart sequence (if the architecture specific
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* machine_restart function calls do_kernel_restart - see below
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* for details).
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* Registered functions are expected to restart the system immediately.
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* If more than one function is registered, the restart handler priority
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* selects which function will be called first.
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*
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* Restart handlers are expected to be registered from non-architecture
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* code, typically from drivers. A typical use case would be a system
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* where restart functionality is provided through a watchdog. Multiple
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* restart handlers may exist; for example, one restart handler might
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* restart the entire system, while another only restarts the CPU.
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* In such cases, the restart handler which only restarts part of the
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* hardware is expected to register with low priority to ensure that
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* it only runs if no other means to restart the system is available.
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*
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* Currently always returns zero, as atomic_notifier_chain_register()
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* always returns zero.
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*/
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int register_restart_handler(struct notifier_block *nb)
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{
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return atomic_notifier_chain_register(&restart_handler_list, nb);
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}
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EXPORT_SYMBOL(register_restart_handler);
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/**
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* unregister_restart_handler - Unregister previously registered
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* restart handler
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* @nb: Hook to be unregistered
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*
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* Unregisters a previously registered restart handler function.
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*
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* Returns zero on success, or %-ENOENT on failure.
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*/
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int unregister_restart_handler(struct notifier_block *nb)
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{
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return atomic_notifier_chain_unregister(&restart_handler_list, nb);
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}
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EXPORT_SYMBOL(unregister_restart_handler);
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/**
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* do_kernel_restart - Execute kernel restart handler call chain
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*
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* Calls functions registered with register_restart_handler.
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*
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* Expected to be called from machine_restart as last step of the restart
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* sequence.
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*
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* Restarts the system immediately if a restart handler function has been
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* registered. Otherwise does nothing.
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*/
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void do_kernel_restart(char *cmd)
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{
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atomic_notifier_call_chain(&restart_handler_list, reboot_mode, cmd);
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}
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void migrate_to_reboot_cpu(void)
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{
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/* The boot cpu is always logical cpu 0 */
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int cpu = reboot_cpu;
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cpu_hotplug_disable();
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/* Make certain the cpu I'm about to reboot on is online */
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if (!cpu_online(cpu))
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cpu = cpumask_first(cpu_online_mask);
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/* Prevent races with other tasks migrating this task */
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current->flags |= PF_NO_SETAFFINITY;
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/* Make certain I only run on the appropriate processor */
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set_cpus_allowed_ptr(current, cpumask_of(cpu));
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}
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/**
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* kernel_restart - reboot the system
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* @cmd: pointer to buffer containing command to execute for restart
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* or %NULL
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*
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* Shutdown everything and perform a clean reboot.
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* This is not safe to call in interrupt context.
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*/
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void kernel_restart(char *cmd)
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{
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kernel_restart_prepare(cmd);
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migrate_to_reboot_cpu();
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syscore_shutdown();
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if (!cmd)
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pr_emerg("Restarting system\n");
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else
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pr_emerg("Restarting system with command '%s'\n", cmd);
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kmsg_dump(KMSG_DUMP_RESTART);
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machine_restart(cmd);
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}
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EXPORT_SYMBOL_GPL(kernel_restart);
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static void kernel_shutdown_prepare(enum system_states state)
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{
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blocking_notifier_call_chain(&reboot_notifier_list,
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(state == SYSTEM_HALT) ? SYS_HALT : SYS_POWER_OFF, NULL);
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system_state = state;
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usermodehelper_disable();
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device_shutdown();
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}
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/**
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* kernel_halt - halt the system
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*
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* Shutdown everything and perform a clean system halt.
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*/
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void kernel_halt(void)
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{
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kernel_shutdown_prepare(SYSTEM_HALT);
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migrate_to_reboot_cpu();
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syscore_shutdown();
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pr_emerg("System halted\n");
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kmsg_dump(KMSG_DUMP_HALT);
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machine_halt();
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}
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EXPORT_SYMBOL_GPL(kernel_halt);
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/**
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* kernel_power_off - power_off the system
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*
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* Shutdown everything and perform a clean system power_off.
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*/
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void kernel_power_off(void)
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{
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kernel_shutdown_prepare(SYSTEM_POWER_OFF);
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if (pm_power_off_prepare)
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pm_power_off_prepare();
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migrate_to_reboot_cpu();
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syscore_shutdown();
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pr_emerg("Power down\n");
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kmsg_dump(KMSG_DUMP_POWEROFF);
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machine_power_off();
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}
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EXPORT_SYMBOL_GPL(kernel_power_off);
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static DEFINE_MUTEX(reboot_mutex);
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/*
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* Reboot system call: for obvious reasons only root may call it,
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* and even root needs to set up some magic numbers in the registers
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* so that some mistake won't make this reboot the whole machine.
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* You can also set the meaning of the ctrl-alt-del-key here.
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*
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* reboot doesn't sync: do that yourself before calling this.
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*/
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SYSCALL_DEFINE4(reboot, int, magic1, int, magic2, unsigned int, cmd,
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void __user *, arg)
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{
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struct pid_namespace *pid_ns = task_active_pid_ns(current);
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char buffer[256];
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int ret = 0;
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/* We only trust the superuser with rebooting the system. */
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if (!ns_capable(pid_ns->user_ns, CAP_SYS_BOOT))
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return -EPERM;
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/* For safety, we require "magic" arguments. */
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if (magic1 != LINUX_REBOOT_MAGIC1 ||
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(magic2 != LINUX_REBOOT_MAGIC2 &&
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magic2 != LINUX_REBOOT_MAGIC2A &&
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magic2 != LINUX_REBOOT_MAGIC2B &&
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magic2 != LINUX_REBOOT_MAGIC2C))
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return -EINVAL;
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/*
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* If pid namespaces are enabled and the current task is in a child
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* pid_namespace, the command is handled by reboot_pid_ns() which will
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* call do_exit().
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*/
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ret = reboot_pid_ns(pid_ns, cmd);
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if (ret)
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return ret;
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/* Instead of trying to make the power_off code look like
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* halt when pm_power_off is not set do it the easy way.
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*/
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if ((cmd == LINUX_REBOOT_CMD_POWER_OFF) && !pm_power_off)
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cmd = LINUX_REBOOT_CMD_HALT;
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mutex_lock(&reboot_mutex);
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switch (cmd) {
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case LINUX_REBOOT_CMD_RESTART:
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kernel_restart(NULL);
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break;
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case LINUX_REBOOT_CMD_CAD_ON:
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C_A_D = 1;
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break;
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case LINUX_REBOOT_CMD_CAD_OFF:
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C_A_D = 0;
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break;
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case LINUX_REBOOT_CMD_HALT:
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kernel_halt();
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do_exit(0);
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panic("cannot halt");
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case LINUX_REBOOT_CMD_POWER_OFF:
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kernel_power_off();
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do_exit(0);
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break;
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case LINUX_REBOOT_CMD_RESTART2:
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ret = strncpy_from_user(&buffer[0], arg, sizeof(buffer) - 1);
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if (ret < 0) {
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ret = -EFAULT;
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break;
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}
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buffer[sizeof(buffer) - 1] = '\0';
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kernel_restart(buffer);
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break;
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#ifdef CONFIG_KEXEC_CORE
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case LINUX_REBOOT_CMD_KEXEC:
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ret = kernel_kexec();
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break;
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#endif
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#ifdef CONFIG_HIBERNATION
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case LINUX_REBOOT_CMD_SW_SUSPEND:
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ret = hibernate();
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break;
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#endif
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default:
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ret = -EINVAL;
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break;
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}
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mutex_unlock(&reboot_mutex);
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return ret;
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}
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static void deferred_cad(struct work_struct *dummy)
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{
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kernel_restart(NULL);
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}
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/*
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* This function gets called by ctrl-alt-del - ie the keyboard interrupt.
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* As it's called within an interrupt, it may NOT sync: the only choice
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* is whether to reboot at once, or just ignore the ctrl-alt-del.
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*/
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void ctrl_alt_del(void)
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{
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static DECLARE_WORK(cad_work, deferred_cad);
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if (C_A_D)
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schedule_work(&cad_work);
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else
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kill_cad_pid(SIGINT, 1);
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}
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char poweroff_cmd[POWEROFF_CMD_PATH_LEN] = "/sbin/poweroff";
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static const char reboot_cmd[] = "/sbin/reboot";
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static int run_cmd(const char *cmd)
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{
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char **argv;
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static char *envp[] = {
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"HOME=/",
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"PATH=/sbin:/bin:/usr/sbin:/usr/bin",
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NULL
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};
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int ret;
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argv = argv_split(GFP_KERNEL, cmd, NULL);
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if (argv) {
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ret = call_usermodehelper(argv[0], argv, envp, UMH_WAIT_EXEC);
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argv_free(argv);
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} else {
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ret = -ENOMEM;
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}
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return ret;
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}
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static int __orderly_reboot(void)
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{
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int ret;
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ret = run_cmd(reboot_cmd);
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if (ret) {
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pr_warn("Failed to start orderly reboot: forcing the issue\n");
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emergency_sync();
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kernel_restart(NULL);
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}
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return ret;
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}
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static int __orderly_poweroff(bool force)
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{
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int ret;
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ret = run_cmd(poweroff_cmd);
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if (ret && force) {
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pr_warn("Failed to start orderly shutdown: forcing the issue\n");
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/*
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* I guess this should try to kick off some daemon to sync and
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* poweroff asap. Or not even bother syncing if we're doing an
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* emergency shutdown?
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*/
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emergency_sync();
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kernel_power_off();
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}
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return ret;
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}
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static bool poweroff_force;
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static void poweroff_work_func(struct work_struct *work)
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{
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__orderly_poweroff(poweroff_force);
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}
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static DECLARE_WORK(poweroff_work, poweroff_work_func);
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/**
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* orderly_poweroff - Trigger an orderly system poweroff
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* @force: force poweroff if command execution fails
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*
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* This may be called from any context to trigger a system shutdown.
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* If the orderly shutdown fails, it will force an immediate shutdown.
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*/
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void orderly_poweroff(bool force)
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{
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if (force) /* do not override the pending "true" */
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poweroff_force = true;
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schedule_work(&poweroff_work);
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}
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EXPORT_SYMBOL_GPL(orderly_poweroff);
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static void reboot_work_func(struct work_struct *work)
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{
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__orderly_reboot();
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}
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static DECLARE_WORK(reboot_work, reboot_work_func);
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|
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/**
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* orderly_reboot - Trigger an orderly system reboot
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*
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* This may be called from any context to trigger a system reboot.
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* If the orderly reboot fails, it will force an immediate reboot.
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*/
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void orderly_reboot(void)
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{
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schedule_work(&reboot_work);
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}
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EXPORT_SYMBOL_GPL(orderly_reboot);
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static int __init reboot_setup(char *str)
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{
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for (;;) {
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/*
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* Having anything passed on the command line via
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* reboot= will cause us to disable DMI checking
|
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* below.
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*/
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reboot_default = 0;
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switch (*str) {
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case 'w':
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reboot_mode = REBOOT_WARM;
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break;
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case 'c':
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reboot_mode = REBOOT_COLD;
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break;
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case 'h':
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reboot_mode = REBOOT_HARD;
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break;
|
|
|
|
case 's':
|
|
{
|
|
int rc;
|
|
|
|
if (isdigit(*(str+1))) {
|
|
rc = kstrtoint(str+1, 0, &reboot_cpu);
|
|
if (rc)
|
|
return rc;
|
|
} else if (str[1] == 'm' && str[2] == 'p' &&
|
|
isdigit(*(str+3))) {
|
|
rc = kstrtoint(str+3, 0, &reboot_cpu);
|
|
if (rc)
|
|
return rc;
|
|
} else
|
|
reboot_mode = REBOOT_SOFT;
|
|
break;
|
|
}
|
|
case 'g':
|
|
reboot_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);
|