3 * $Id: sysrq.c,v 1.15 1998/08/23 14:56:41 mj Exp $
5 * Linux Magic System Request Key Hacks
7 * (c) 1997 Martin Mares <mj@atrey.karlin.mff.cuni.cz>
8 * based on ideas by Pavel Machek <pavel@atrey.karlin.mff.cuni.cz>
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
15 #include <linux/sched.h>
16 #include <linux/interrupt.h>
19 #include <linux/tty.h>
20 #include <linux/mount.h>
21 #include <linux/kdev_t.h>
22 #include <linux/major.h>
23 #include <linux/reboot.h>
24 #include <linux/sysrq.h>
25 #include <linux/kbd_kern.h>
26 #include <linux/quotaops.h>
27 #include <linux/smp_lock.h>
28 #include <linux/kernel.h>
29 #include <linux/module.h>
30 #include <linux/suspend.h>
31 #include <linux/writeback.h>
32 #include <linux/buffer_head.h> /* for fsync_bdev() */
33 #include <linux/swap.h>
34 #include <linux/spinlock.h>
35 #include <linux/vt_kern.h>
36 #include <linux/workqueue.h>
37 #include <linux/kexec.h>
39 #include <asm/ptrace.h>
41 /* Whether we react on sysrq keys or just ignore them */
42 int sysrq_enabled
= 1;
44 static void sysrq_handle_loglevel(int key
, struct pt_regs
*pt_regs
,
45 struct tty_struct
*tty
)
50 printk("Loglevel set to %d\n", i
);
53 static struct sysrq_key_op sysrq_loglevel_op
= {
54 .handler
= sysrq_handle_loglevel
,
55 .help_msg
= "loglevel0-8",
56 .action_msg
= "Changing Loglevel",
57 .enable_mask
= SYSRQ_ENABLE_LOG
,
61 static void sysrq_handle_SAK(int key
, struct pt_regs
*pt_regs
,
62 struct tty_struct
*tty
)
66 reset_vc(vc_cons
[fg_console
].d
);
68 static struct sysrq_key_op sysrq_SAK_op
= {
69 .handler
= sysrq_handle_SAK
,
72 .enable_mask
= SYSRQ_ENABLE_KEYBOARD
,
75 #define sysrq_SAK_op (*(struct sysrq_key_op *)0)
79 static void sysrq_handle_unraw(int key
, struct pt_regs
*pt_regs
,
80 struct tty_struct
*tty
)
82 struct kbd_struct
*kbd
= &kbd_table
[fg_console
];
85 kbd
->kbdmode
= VC_XLATE
;
87 static struct sysrq_key_op sysrq_unraw_op
= {
88 .handler
= sysrq_handle_unraw
,
90 .action_msg
= "Keyboard mode set to XLATE",
91 .enable_mask
= SYSRQ_ENABLE_KEYBOARD
,
94 #define sysrq_unraw_op (*(struct sysrq_key_op *)0)
95 #endif /* CONFIG_VT */
98 static void sysrq_handle_crashdump(int key
, struct pt_regs
*pt_regs
,
99 struct tty_struct
*tty
)
101 crash_kexec(pt_regs
);
103 static struct sysrq_key_op sysrq_crashdump_op
= {
104 .handler
= sysrq_handle_crashdump
,
105 .help_msg
= "Crashdump",
106 .action_msg
= "Trigger a crashdump",
107 .enable_mask
= SYSRQ_ENABLE_DUMP
,
110 #define sysrq_crashdump_op (*(struct sysrq_key_op *)0)
113 static void sysrq_handle_reboot(int key
, struct pt_regs
*pt_regs
,
114 struct tty_struct
*tty
)
119 static struct sysrq_key_op sysrq_reboot_op
= {
120 .handler
= sysrq_handle_reboot
,
121 .help_msg
= "reBoot",
122 .action_msg
= "Resetting",
123 .enable_mask
= SYSRQ_ENABLE_BOOT
,
126 static void sysrq_handle_sync(int key
, struct pt_regs
*pt_regs
,
127 struct tty_struct
*tty
)
131 static struct sysrq_key_op sysrq_sync_op
= {
132 .handler
= sysrq_handle_sync
,
134 .action_msg
= "Emergency Sync",
135 .enable_mask
= SYSRQ_ENABLE_SYNC
,
138 static void sysrq_handle_mountro(int key
, struct pt_regs
*pt_regs
,
139 struct tty_struct
*tty
)
143 static struct sysrq_key_op sysrq_mountro_op
= {
144 .handler
= sysrq_handle_mountro
,
145 .help_msg
= "Unmount",
146 .action_msg
= "Emergency Remount R/O",
147 .enable_mask
= SYSRQ_ENABLE_REMOUNT
,
150 #ifdef CONFIG_DEBUG_MUTEXES
151 static void sysrq_handle_showlocks(int key
, struct pt_regs
*pt_regs
,
152 struct tty_struct
*tty
)
154 mutex_debug_show_all_locks();
156 static struct sysrq_key_op sysrq_showlocks_op
= {
157 .handler
= sysrq_handle_showlocks
,
158 .help_msg
= "show-all-locks(D)",
159 .action_msg
= "Show Locks Held",
162 #define sysrq_showlocks_op (*(struct sysrq_key_op *)0)
165 static void sysrq_handle_showregs(int key
, struct pt_regs
*pt_regs
,
166 struct tty_struct
*tty
)
171 static struct sysrq_key_op sysrq_showregs_op
= {
172 .handler
= sysrq_handle_showregs
,
173 .help_msg
= "showPc",
174 .action_msg
= "Show Regs",
175 .enable_mask
= SYSRQ_ENABLE_DUMP
,
178 static void sysrq_handle_showstate(int key
, struct pt_regs
*pt_regs
,
179 struct tty_struct
*tty
)
183 static struct sysrq_key_op sysrq_showstate_op
= {
184 .handler
= sysrq_handle_showstate
,
185 .help_msg
= "showTasks",
186 .action_msg
= "Show State",
187 .enable_mask
= SYSRQ_ENABLE_DUMP
,
190 static void sysrq_handle_showmem(int key
, struct pt_regs
*pt_regs
,
191 struct tty_struct
*tty
)
195 static struct sysrq_key_op sysrq_showmem_op
= {
196 .handler
= sysrq_handle_showmem
,
197 .help_msg
= "showMem",
198 .action_msg
= "Show Memory",
199 .enable_mask
= SYSRQ_ENABLE_DUMP
,
203 * Signal sysrq helper function. Sends a signal to all user processes.
205 static void send_sig_all(int sig
)
207 struct task_struct
*p
;
209 for_each_process(p
) {
210 if (p
->mm
&& p
->pid
!= 1)
211 /* Not swapper, init nor kernel thread */
216 static void sysrq_handle_term(int key
, struct pt_regs
*pt_regs
,
217 struct tty_struct
*tty
)
219 send_sig_all(SIGTERM
);
220 console_loglevel
= 8;
222 static struct sysrq_key_op sysrq_term_op
= {
223 .handler
= sysrq_handle_term
,
225 .action_msg
= "Terminate All Tasks",
226 .enable_mask
= SYSRQ_ENABLE_SIGNAL
,
229 static void moom_callback(void *ignored
)
231 out_of_memory(&NODE_DATA(0)->node_zonelists
[ZONE_NORMAL
],
235 static DECLARE_WORK(moom_work
, moom_callback
, NULL
);
237 static void sysrq_handle_moom(int key
, struct pt_regs
*pt_regs
,
238 struct tty_struct
*tty
)
240 schedule_work(&moom_work
);
242 static struct sysrq_key_op sysrq_moom_op
= {
243 .handler
= sysrq_handle_moom
,
245 .action_msg
= "Manual OOM execution",
248 static void sysrq_handle_kill(int key
, struct pt_regs
*pt_regs
,
249 struct tty_struct
*tty
)
251 send_sig_all(SIGKILL
);
252 console_loglevel
= 8;
254 static struct sysrq_key_op sysrq_kill_op
= {
255 .handler
= sysrq_handle_kill
,
257 .action_msg
= "Kill All Tasks",
258 .enable_mask
= SYSRQ_ENABLE_SIGNAL
,
261 static void sysrq_handle_unrt(int key
, struct pt_regs
*pt_regs
,
262 struct tty_struct
*tty
)
264 normalize_rt_tasks();
266 static struct sysrq_key_op sysrq_unrt_op
= {
267 .handler
= sysrq_handle_unrt
,
269 .action_msg
= "Nice All RT Tasks",
270 .enable_mask
= SYSRQ_ENABLE_RTNICE
,
273 /* Key Operations table and lock */
274 static DEFINE_SPINLOCK(sysrq_key_table_lock
);
276 static struct sysrq_key_op
*sysrq_key_table
[36] = {
277 &sysrq_loglevel_op
, /* 0 */
278 &sysrq_loglevel_op
, /* 1 */
279 &sysrq_loglevel_op
, /* 2 */
280 &sysrq_loglevel_op
, /* 3 */
281 &sysrq_loglevel_op
, /* 4 */
282 &sysrq_loglevel_op
, /* 5 */
283 &sysrq_loglevel_op
, /* 6 */
284 &sysrq_loglevel_op
, /* 7 */
285 &sysrq_loglevel_op
, /* 8 */
286 &sysrq_loglevel_op
, /* 9 */
289 * Don't use for system provided sysrqs, it is handled specially on
290 * sparc and will never arrive
293 &sysrq_reboot_op
, /* b */
294 &sysrq_crashdump_op
, /* c */
295 &sysrq_showlocks_op
, /* d */
296 &sysrq_term_op
, /* e */
297 &sysrq_moom_op
, /* f */
300 &sysrq_kill_op
, /* i */
302 &sysrq_SAK_op
, /* k */
304 &sysrq_showmem_op
, /* m */
305 &sysrq_unrt_op
, /* n */
306 /* This will often be registered as 'Off' at init time */
308 &sysrq_showregs_op
, /* p */
310 &sysrq_unraw_op
, /* r */
311 &sysrq_sync_op
, /* s */
312 &sysrq_showstate_op
, /* t */
313 &sysrq_mountro_op
, /* u */
314 /* May be assigned at init time by SMP VOYAGER */
322 /* key2index calculation, -1 on invalid index */
323 static int sysrq_key_table_key2index(int key
)
327 if ((key
>= '0') && (key
<= '9'))
329 else if ((key
>= 'a') && (key
<= 'z'))
330 retval
= key
+ 10 - 'a';
337 * get and put functions for the table, exposed to modules.
339 struct sysrq_key_op
*__sysrq_get_key_op(int key
)
341 struct sysrq_key_op
*op_p
= NULL
;
344 i
= sysrq_key_table_key2index(key
);
346 op_p
= sysrq_key_table
[i
];
350 static void __sysrq_put_key_op(int key
, struct sysrq_key_op
*op_p
)
352 int i
= sysrq_key_table_key2index(key
);
355 sysrq_key_table
[i
] = op_p
;
359 * This is the non-locking version of handle_sysrq. It must/can only be called
360 * by sysrq key handlers, as they are inside of the lock
362 void __handle_sysrq(int key
, struct pt_regs
*pt_regs
, struct tty_struct
*tty
,
365 struct sysrq_key_op
*op_p
;
370 spin_lock_irqsave(&sysrq_key_table_lock
, flags
);
371 orig_log_level
= console_loglevel
;
372 console_loglevel
= 7;
373 printk(KERN_INFO
"SysRq : ");
375 op_p
= __sysrq_get_key_op(key
);
378 * Should we check for enabled operations (/proc/sysrq-trigger
379 * should not) and is the invoked operation enabled?
381 if (!check_mask
|| sysrq_enabled
== 1 ||
382 (sysrq_enabled
& op_p
->enable_mask
)) {
383 printk("%s\n", op_p
->action_msg
);
384 console_loglevel
= orig_log_level
;
385 op_p
->handler(key
, pt_regs
, tty
);
387 printk("This sysrq operation is disabled.\n");
391 /* Only print the help msg once per handler */
392 for (i
= 0; i
< ARRAY_SIZE(sysrq_key_table
); i
++) {
393 if (sysrq_key_table
[i
]) {
396 for (j
= 0; sysrq_key_table
[i
] !=
397 sysrq_key_table
[j
]; j
++)
401 printk("%s ", sysrq_key_table
[i
]->help_msg
);
405 console_loglevel
= orig_log_level
;
407 spin_unlock_irqrestore(&sysrq_key_table_lock
, flags
);
411 * This function is called by the keyboard handler when SysRq is pressed
412 * and any other keycode arrives.
414 void handle_sysrq(int key
, struct pt_regs
*pt_regs
, struct tty_struct
*tty
)
418 __handle_sysrq(key
, pt_regs
, tty
, 1);
420 EXPORT_SYMBOL(handle_sysrq
);
422 static int __sysrq_swap_key_ops(int key
, struct sysrq_key_op
*insert_op_p
,
423 struct sysrq_key_op
*remove_op_p
)
429 spin_lock_irqsave(&sysrq_key_table_lock
, flags
);
430 if (__sysrq_get_key_op(key
) == remove_op_p
) {
431 __sysrq_put_key_op(key
, insert_op_p
);
436 spin_unlock_irqrestore(&sysrq_key_table_lock
, flags
);
440 int register_sysrq_key(int key
, struct sysrq_key_op
*op_p
)
442 return __sysrq_swap_key_ops(key
, op_p
, NULL
);
444 EXPORT_SYMBOL(register_sysrq_key
);
446 int unregister_sysrq_key(int key
, struct sysrq_key_op
*op_p
)
448 return __sysrq_swap_key_ops(key
, NULL
, op_p
);
450 EXPORT_SYMBOL(unregister_sysrq_key
);