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
)
120 static struct sysrq_key_op sysrq_reboot_op
= {
121 .handler
= sysrq_handle_reboot
,
122 .help_msg
= "reBoot",
123 .action_msg
= "Resetting",
124 .enable_mask
= SYSRQ_ENABLE_BOOT
,
127 static void sysrq_handle_sync(int key
, struct pt_regs
*pt_regs
,
128 struct tty_struct
*tty
)
132 static struct sysrq_key_op sysrq_sync_op
= {
133 .handler
= sysrq_handle_sync
,
135 .action_msg
= "Emergency Sync",
136 .enable_mask
= SYSRQ_ENABLE_SYNC
,
139 static void sysrq_handle_mountro(int key
, struct pt_regs
*pt_regs
,
140 struct tty_struct
*tty
)
144 static struct sysrq_key_op sysrq_mountro_op
= {
145 .handler
= sysrq_handle_mountro
,
146 .help_msg
= "Unmount",
147 .action_msg
= "Emergency Remount R/O",
148 .enable_mask
= SYSRQ_ENABLE_REMOUNT
,
151 #ifdef CONFIG_LOCKDEP
152 static void sysrq_handle_showlocks(int key
, struct pt_regs
*pt_regs
,
153 struct tty_struct
*tty
)
155 debug_show_all_locks();
158 static struct sysrq_key_op sysrq_showlocks_op
= {
159 .handler
= sysrq_handle_showlocks
,
160 .help_msg
= "show-all-locks(D)",
161 .action_msg
= "Show Locks Held",
164 #define sysrq_showlocks_op (*(struct sysrq_key_op *)0)
167 static void sysrq_handle_showregs(int key
, struct pt_regs
*pt_regs
,
168 struct tty_struct
*tty
)
173 static struct sysrq_key_op sysrq_showregs_op
= {
174 .handler
= sysrq_handle_showregs
,
175 .help_msg
= "showPc",
176 .action_msg
= "Show Regs",
177 .enable_mask
= SYSRQ_ENABLE_DUMP
,
180 static void sysrq_handle_showstate(int key
, struct pt_regs
*pt_regs
,
181 struct tty_struct
*tty
)
185 static struct sysrq_key_op sysrq_showstate_op
= {
186 .handler
= sysrq_handle_showstate
,
187 .help_msg
= "showTasks",
188 .action_msg
= "Show State",
189 .enable_mask
= SYSRQ_ENABLE_DUMP
,
192 static void sysrq_handle_showmem(int key
, struct pt_regs
*pt_regs
,
193 struct tty_struct
*tty
)
197 static struct sysrq_key_op sysrq_showmem_op
= {
198 .handler
= sysrq_handle_showmem
,
199 .help_msg
= "showMem",
200 .action_msg
= "Show Memory",
201 .enable_mask
= SYSRQ_ENABLE_DUMP
,
205 * Signal sysrq helper function. Sends a signal to all user processes.
207 static void send_sig_all(int sig
)
209 struct task_struct
*p
;
211 for_each_process(p
) {
212 if (p
->mm
&& !is_init(p
))
213 /* Not swapper, init nor kernel thread */
218 static void sysrq_handle_term(int key
, struct pt_regs
*pt_regs
,
219 struct tty_struct
*tty
)
221 send_sig_all(SIGTERM
);
222 console_loglevel
= 8;
224 static struct sysrq_key_op sysrq_term_op
= {
225 .handler
= sysrq_handle_term
,
227 .action_msg
= "Terminate All Tasks",
228 .enable_mask
= SYSRQ_ENABLE_SIGNAL
,
231 static void moom_callback(void *ignored
)
233 out_of_memory(&NODE_DATA(0)->node_zonelists
[ZONE_NORMAL
],
237 static DECLARE_WORK(moom_work
, moom_callback
, NULL
);
239 static void sysrq_handle_moom(int key
, struct pt_regs
*pt_regs
,
240 struct tty_struct
*tty
)
242 schedule_work(&moom_work
);
244 static struct sysrq_key_op sysrq_moom_op
= {
245 .handler
= sysrq_handle_moom
,
247 .action_msg
= "Manual OOM execution",
250 static void sysrq_handle_kill(int key
, struct pt_regs
*pt_regs
,
251 struct tty_struct
*tty
)
253 send_sig_all(SIGKILL
);
254 console_loglevel
= 8;
256 static struct sysrq_key_op sysrq_kill_op
= {
257 .handler
= sysrq_handle_kill
,
259 .action_msg
= "Kill All Tasks",
260 .enable_mask
= SYSRQ_ENABLE_SIGNAL
,
263 static void sysrq_handle_unrt(int key
, struct pt_regs
*pt_regs
,
264 struct tty_struct
*tty
)
266 normalize_rt_tasks();
268 static struct sysrq_key_op sysrq_unrt_op
= {
269 .handler
= sysrq_handle_unrt
,
271 .action_msg
= "Nice All RT Tasks",
272 .enable_mask
= SYSRQ_ENABLE_RTNICE
,
275 /* Key Operations table and lock */
276 static DEFINE_SPINLOCK(sysrq_key_table_lock
);
278 static struct sysrq_key_op
*sysrq_key_table
[36] = {
279 &sysrq_loglevel_op
, /* 0 */
280 &sysrq_loglevel_op
, /* 1 */
281 &sysrq_loglevel_op
, /* 2 */
282 &sysrq_loglevel_op
, /* 3 */
283 &sysrq_loglevel_op
, /* 4 */
284 &sysrq_loglevel_op
, /* 5 */
285 &sysrq_loglevel_op
, /* 6 */
286 &sysrq_loglevel_op
, /* 7 */
287 &sysrq_loglevel_op
, /* 8 */
288 &sysrq_loglevel_op
, /* 9 */
291 * Don't use for system provided sysrqs, it is handled specially on
292 * sparc and will never arrive
295 &sysrq_reboot_op
, /* b */
296 &sysrq_crashdump_op
, /* c */
297 &sysrq_showlocks_op
, /* d */
298 &sysrq_term_op
, /* e */
299 &sysrq_moom_op
, /* f */
302 &sysrq_kill_op
, /* i */
304 &sysrq_SAK_op
, /* k */
306 &sysrq_showmem_op
, /* m */
307 &sysrq_unrt_op
, /* n */
308 /* This will often be registered as 'Off' at init time */
310 &sysrq_showregs_op
, /* p */
312 &sysrq_unraw_op
, /* r */
313 &sysrq_sync_op
, /* s */
314 &sysrq_showstate_op
, /* t */
315 &sysrq_mountro_op
, /* u */
316 /* May be assigned at init time by SMP VOYAGER */
324 /* key2index calculation, -1 on invalid index */
325 static int sysrq_key_table_key2index(int key
)
329 if ((key
>= '0') && (key
<= '9'))
331 else if ((key
>= 'a') && (key
<= 'z'))
332 retval
= key
+ 10 - 'a';
339 * get and put functions for the table, exposed to modules.
341 struct sysrq_key_op
*__sysrq_get_key_op(int key
)
343 struct sysrq_key_op
*op_p
= NULL
;
346 i
= sysrq_key_table_key2index(key
);
348 op_p
= sysrq_key_table
[i
];
352 static void __sysrq_put_key_op(int key
, struct sysrq_key_op
*op_p
)
354 int i
= sysrq_key_table_key2index(key
);
357 sysrq_key_table
[i
] = op_p
;
361 * This is the non-locking version of handle_sysrq. It must/can only be called
362 * by sysrq key handlers, as they are inside of the lock
364 void __handle_sysrq(int key
, struct pt_regs
*pt_regs
, struct tty_struct
*tty
,
367 struct sysrq_key_op
*op_p
;
372 spin_lock_irqsave(&sysrq_key_table_lock
, flags
);
373 orig_log_level
= console_loglevel
;
374 console_loglevel
= 7;
375 printk(KERN_INFO
"SysRq : ");
377 op_p
= __sysrq_get_key_op(key
);
380 * Should we check for enabled operations (/proc/sysrq-trigger
381 * should not) and is the invoked operation enabled?
383 if (!check_mask
|| sysrq_enabled
== 1 ||
384 (sysrq_enabled
& op_p
->enable_mask
)) {
385 printk("%s\n", op_p
->action_msg
);
386 console_loglevel
= orig_log_level
;
387 op_p
->handler(key
, pt_regs
, tty
);
389 printk("This sysrq operation is disabled.\n");
393 /* Only print the help msg once per handler */
394 for (i
= 0; i
< ARRAY_SIZE(sysrq_key_table
); i
++) {
395 if (sysrq_key_table
[i
]) {
398 for (j
= 0; sysrq_key_table
[i
] !=
399 sysrq_key_table
[j
]; j
++)
403 printk("%s ", sysrq_key_table
[i
]->help_msg
);
407 console_loglevel
= orig_log_level
;
409 spin_unlock_irqrestore(&sysrq_key_table_lock
, flags
);
413 * This function is called by the keyboard handler when SysRq is pressed
414 * and any other keycode arrives.
416 void handle_sysrq(int key
, struct pt_regs
*pt_regs
, struct tty_struct
*tty
)
420 __handle_sysrq(key
, pt_regs
, tty
, 1);
422 EXPORT_SYMBOL(handle_sysrq
);
424 static int __sysrq_swap_key_ops(int key
, struct sysrq_key_op
*insert_op_p
,
425 struct sysrq_key_op
*remove_op_p
)
431 spin_lock_irqsave(&sysrq_key_table_lock
, flags
);
432 if (__sysrq_get_key_op(key
) == remove_op_p
) {
433 __sysrq_put_key_op(key
, insert_op_p
);
438 spin_unlock_irqrestore(&sysrq_key_table_lock
, flags
);
442 int register_sysrq_key(int key
, struct sysrq_key_op
*op_p
)
444 return __sysrq_swap_key_ops(key
, op_p
, NULL
);
446 EXPORT_SYMBOL(register_sysrq_key
);
448 int unregister_sysrq_key(int key
, struct sysrq_key_op
*op_p
)
450 return __sysrq_swap_key_ops(key
, NULL
, op_p
);
452 EXPORT_SYMBOL(unregister_sysrq_key
);