1/* SPDX-License-Identifier: GPL-2.0 */
2/* -*- linux-c -*-
3 *
4 *	$Id: sysrq.h,v 1.3 1997/07/17 11:54:33 mj Exp $
5 *
6 *	Linux Magic System Request Key Hacks
7 *
8 *	(c) 1997 Martin Mares <mj@atrey.karlin.mff.cuni.cz>
9 *
10 *	(c) 2000 Crutcher Dunnavant <crutcher+kernel@datastacks.com>
11 *	overhauled to use key registration
12 *	based upon discusions in irc://irc.openprojects.net/#kernelnewbies
13 */
14
15#ifndef _LINUX_SYSRQ_H
16#define _LINUX_SYSRQ_H
17
18#include <linux/errno.h>
19#include <linux/types.h>
20
21/* Possible values of bitmask for enabling sysrq functions */
22/* 0x0001 is reserved for enable everything */
23#define SYSRQ_ENABLE_LOG	0x0002
24#define SYSRQ_ENABLE_KEYBOARD	0x0004
25#define SYSRQ_ENABLE_DUMP	0x0008
26#define SYSRQ_ENABLE_SYNC	0x0010
27#define SYSRQ_ENABLE_REMOUNT	0x0020
28#define SYSRQ_ENABLE_SIGNAL	0x0040
29#define SYSRQ_ENABLE_BOOT	0x0080
30#define SYSRQ_ENABLE_RTNICE	0x0100
31
32struct sysrq_key_op {
33	void (* const handler)(u8);
34	const char * const help_msg;
35	const char * const action_msg;
36	const int enable_mask;
37};
38
39#ifdef CONFIG_MAGIC_SYSRQ
40
41/* Generic SysRq interface -- you may call it from any device driver, supplying
42 * ASCII code of the key, pointer to registers and kbd/tty structs (if they
43 * are available -- else NULL's).
44 */
45
46void handle_sysrq(u8 key);
47void __handle_sysrq(u8 key, bool check_mask);
48int register_sysrq_key(u8 key, const struct sysrq_key_op *op);
49int unregister_sysrq_key(u8 key, const struct sysrq_key_op *op);
50extern const struct sysrq_key_op *__sysrq_reboot_op;
51
52int sysrq_toggle_support(int enable_mask);
53int sysrq_mask(void);
54
55#else
56
57static inline void handle_sysrq(u8 key)
58{
59}
60
61static inline void __handle_sysrq(u8 key, bool check_mask)
62{
63}
64
65static inline int register_sysrq_key(u8 key, const struct sysrq_key_op *op)
66{
67	return -EINVAL;
68}
69
70static inline int unregister_sysrq_key(u8 key, const struct sysrq_key_op *op)
71{
72	return -EINVAL;
73}
74
75static inline int sysrq_mask(void)
76{
77	/* Magic SysRq disabled mask */
78	return 0;
79}
80
81#endif
82
83#endif /* _LINUX_SYSRQ_H */
84