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