kernel/power/poweroff.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * poweroff.c - sysrq handler to gracefully power down machine.
   4  */
   5
   6 #include <linux/kernel.h>
   7 #include <linux/sysrq.h>
   8 #include <linux/init.h>
   9 #include <linux/pm.h>
  10 #include <linux/workqueue.h>
  11 #include <linux/reboot.h>
  12 #include <linux/cpumask.h>
  13
  14 /*
  15  * When the user hits Sys-Rq o to power down the machine this is the
  16  * callback we use.
  17  */
  18
  19 static void do_poweroff(struct work_struct *dummy)
  20 {
  21         kernel_power_off();
  22 }
  23
  24 static DECLARE_WORK(poweroff_work, do_poweroff);
  25
  26 static void handle_poweroff(int key)
  27 {
  28         /* run sysrq poweroff on boot cpu */
  29         schedule_work_on(cpumask_first(cpu_online_mask), &poweroff_work);
  30 }
  31
  32 static struct sysrq_key_op      sysrq_poweroff_op = {
  33         .handler        = handle_poweroff,
  34         .help_msg       = "poweroff(o)",
  35         .action_msg     = "Power Off",
  36         .enable_mask    = SYSRQ_ENABLE_BOOT,
  37 };
  38
  39 static int __init pm_sysrq_init(void)
  40 {
  41         register_sysrq_key('o', &sysrq_poweroff_op);
  42         return 0;
  43 }
  44
  45 subsys_initcall(pm_sysrq_init);