1 /* -*- linux-c -*-
2 *
3 * $Id: sysrq.h,v 1.3 1997/07/17 11:54:33 mj Exp $
4 *
5 * Linux Magic System Request Key Hacks
6 *
7 * (c) 1997 Martin Mares <mj@atrey.karlin.mff.cuni.cz>
8 *
9 * (c) 2000 Crutcher Dunnavant <crutcher+kernel@datastacks.com>
10 * overhauled to use key registration
11 * based upon discusions in irc://irc.openprojects.net/#kernelnewbies
12 */
13 #ifndef __LINUX_SYSRQ_H__
14 #define __LINUX_SYSRQ_H__
15
16 #include <linux/config.h>
17
18 struct pt_regs;
19 struct kbd_struct;
20 struct tty_struct;
21
22 struct sysrq_key_op {
23 void (*handler)(int, struct pt_regs *,
24 struct kbd_struct *, struct tty_struct *);
25 char *help_msg;
26 char *action_msg;
27 };
28
29 #ifdef CONFIG_MAGIC_SYSRQ
30
31 /* Generic SysRq interface -- you may call it from any device driver, supplying
32 * ASCII code of the key, pointer to registers and kbd/tty structs (if they
33 * are available -- else NULL's).
34 */
35
36 void handle_sysrq(int, struct pt_regs *,
37 struct kbd_struct *, struct tty_struct *);
38
39
40 /*
41 * Nonlocking version of handle sysrq, used by sysrq handlers that need to
42 * call sysrq handlers
43 */
44
45 void __handle_sysrq_nolock(int, struct pt_regs *,
46 struct kbd_struct *, struct tty_struct *);
47
48
49
50 /*
51 * Sysrq registration manipulation functions
52 */
53
54 void __sysrq_lock_table (void);
55 void __sysrq_unlock_table (void);
56 struct sysrq_key_op *__sysrq_get_key_op (int key);
57 void __sysrq_put_key_op (int key, struct sysrq_key_op *op_p);
58
59 extern __inline__ int
__sysrq_swap_key_ops_nolock(int key,struct sysrq_key_op * insert_op_p,struct sysrq_key_op * remove_op_p)60 __sysrq_swap_key_ops_nolock(int key, struct sysrq_key_op *insert_op_p,
61 struct sysrq_key_op *remove_op_p)
62 {
63 int retval;
64 if (__sysrq_get_key_op(key) == remove_op_p) {
65 __sysrq_put_key_op(key, insert_op_p);
66 retval = 0;
67 } else {
68 retval = -1;
69 }
70 return retval;
71 }
72
73 extern __inline__ int
__sysrq_swap_key_ops(int key,struct sysrq_key_op * insert_op_p,struct sysrq_key_op * remove_op_p)74 __sysrq_swap_key_ops(int key, struct sysrq_key_op *insert_op_p,
75 struct sysrq_key_op *remove_op_p) {
76 int retval;
77 __sysrq_lock_table();
78 retval = __sysrq_swap_key_ops_nolock(key, insert_op_p, remove_op_p);
79 __sysrq_unlock_table();
80 return retval;
81 }
82
register_sysrq_key(int key,struct sysrq_key_op * op_p)83 static inline int register_sysrq_key(int key, struct sysrq_key_op *op_p)
84 {
85 return __sysrq_swap_key_ops(key, op_p, NULL);
86 }
87
unregister_sysrq_key(int key,struct sysrq_key_op * op_p)88 static inline int unregister_sysrq_key(int key, struct sysrq_key_op *op_p)
89 {
90 return __sysrq_swap_key_ops(key, NULL, op_p);
91 }
92
93 #else
94
__reterr(void)95 static inline int __reterr(void)
96 {
97 return -EINVAL;
98 }
99
100 #define register_sysrq_key(ig,nore) __reterr()
101 #define unregister_sysrq_key(ig,nore) __reterr()
102
103 #endif
104
105
106 /* Deferred actions */
107
108 extern volatile int emergency_sync_scheduled;
109
110 #define EMERG_SYNC 1
111 #define EMERG_REMOUNT 2
112
113 void do_emergency_sync(void);
114
115 #ifdef CONFIG_MAGIC_SYSRQ
116 #define CHECK_EMERGENCY_SYNC \
117 if (emergency_sync_scheduled) \
118 do_emergency_sync();
119 #else
120 #define CHECK_EMERGENCY_SYNC
121 #endif
122
123 #endif /* __LINUX_SYSRQ_H__ */
124