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
32 struct 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
46 void handle_sysrq(u8 key);
47 void __handle_sysrq(u8 key, bool check_mask);
48 int register_sysrq_key(u8 key, const struct sysrq_key_op *op);
49 int unregister_sysrq_key(u8 key, const struct sysrq_key_op *op);
50 extern const struct sysrq_key_op *__sysrq_reboot_op;
51
52 int sysrq_toggle_support(int enable_mask);
53 int sysrq_mask(void);
54
55 #else
56
57 static inline void handle_sysrq(u8 key)
58 {
59 }
60
61 static inline void __handle_sysrq(u8 key, bool check_mask)
62 {
63 }
64
65 static inline int register_sysrq_key(u8 key, const struct sysrq_key_op *op)
66 {
67 return -EINVAL;
68 }
69
70 static inline int unregister_sysrq_key(u8 key, const struct sysrq_key_op *op)
71 {
72 return -EINVAL;
73 }
74
75 static 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
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