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(u8 key) 27 { 28 /* run sysrq poweroff on boot cpu */ 29 schedule_work_on(cpumask_first(cpu_online_mask), &poweroff_work); 30 } 31 32 static const 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); 46