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
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