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>
38 #include <linux/irq.h>
40 #include <asm/ptrace.h>
41 #include <asm/irq_regs.h>
43 /* Whether we react on sysrq keys or just ignore them */
44 int sysrq_enabled
= 1;
46 static void sysrq_handle_loglevel(int key
, struct tty_struct
*tty
)
51 printk("Loglevel set to %d\n", i
);
54 static struct sysrq_key_op sysrq_loglevel_op
= {
55 .handler
= sysrq_handle_loglevel
,
56 .help_msg
= "loglevel0-8",
57 .action_msg
= "Changing Loglevel",
58 .enable_mask
= SYSRQ_ENABLE_LOG
,
62 static void sysrq_handle_SAK(int key
, 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 tty_struct
*tty
)
81 struct kbd_struct
*kbd
= &kbd_table
[fg_console
];
84 kbd
->kbdmode
= VC_XLATE
;
86 static struct sysrq_key_op sysrq_unraw_op
= {
87 .handler
= sysrq_handle_unraw
,
89 .action_msg
= "Keyboard mode set to XLATE",
90 .enable_mask
= SYSRQ_ENABLE_KEYBOARD
,
93 #define sysrq_unraw_op (*(struct sysrq_key_op *)0)
94 #endif /* CONFIG_VT */
97 static void sysrq_handle_crashdump(int key
, struct tty_struct
*tty
)
99 crash_kexec(get_irq_regs());
101 static struct sysrq_key_op sysrq_crashdump_op
= {
102 .handler
= sysrq_handle_crashdump
,
103 .help_msg
= "Crashdump",
104 .action_msg
= "Trigger a crashdump",
105 .enable_mask
= SYSRQ_ENABLE_DUMP
,
108 #define sysrq_crashdump_op (*(struct sysrq_key_op *)0)
111 static void sysrq_handle_reboot(int key
, struct tty_struct
*tty
)
117 static struct sysrq_key_op sysrq_reboot_op
= {
118 .handler
= sysrq_handle_reboot
,
119 .help_msg
= "reBoot",
120 .action_msg
= "Resetting",
121 .enable_mask
= SYSRQ_ENABLE_BOOT
,
124 static void sysrq_handle_sync(int key
, struct tty_struct
*tty
)
128 static struct sysrq_key_op sysrq_sync_op
= {
129 .handler
= sysrq_handle_sync
,
131 .action_msg
= "Emergency Sync",
132 .enable_mask
= SYSRQ_ENABLE_SYNC
,
135 static void sysrq_handle_mountro(int key
, struct tty_struct
*tty
)
139 static struct sysrq_key_op sysrq_mountro_op
= {
140 .handler
= sysrq_handle_mountro
,
141 .help_msg
= "Unmount",
142 .action_msg
= "Emergency Remount R/O",
143 .enable_mask
= SYSRQ_ENABLE_REMOUNT
,
146 #ifdef CONFIG_LOCKDEP
147 static void sysrq_handle_showlocks(int key
, struct tty_struct
*tty
)
149 debug_show_all_locks();
152 static struct sysrq_key_op sysrq_showlocks_op
= {
153 .handler
= sysrq_handle_showlocks
,
154 .help_msg
= "show-all-locks(D)",
155 .action_msg
= "Show Locks Held",
158 #define sysrq_showlocks_op (*(struct sysrq_key_op *)0)
161 static void sysrq_handle_showregs(int key
, struct tty_struct
*tty
)
163 struct pt_regs
*regs
= get_irq_regs();
167 static struct sysrq_key_op sysrq_showregs_op
= {
168 .handler
= sysrq_handle_showregs
,
169 .help_msg
= "showPc",
170 .action_msg
= "Show Regs",
171 .enable_mask
= SYSRQ_ENABLE_DUMP
,
174 static void sysrq_handle_showstate(int key
, struct tty_struct
*tty
)
178 static struct sysrq_key_op sysrq_showstate_op
= {
179 .handler
= sysrq_handle_showstate
,
180 .help_msg
= "showTasks",
181 .action_msg
= "Show State",
182 .enable_mask
= SYSRQ_ENABLE_DUMP
,
185 static void sysrq_handle_showmem(int key
, struct tty_struct
*tty
)
189 static struct sysrq_key_op sysrq_showmem_op
= {
190 .handler
= sysrq_handle_showmem
,
191 .help_msg
= "showMem",
192 .action_msg
= "Show Memory",
193 .enable_mask
= SYSRQ_ENABLE_DUMP
,
197 * Signal sysrq helper function. Sends a signal to all user processes.
199 static void send_sig_all(int sig
)
201 struct task_struct
*p
;
203 for_each_process(p
) {
204 if (p
->mm
&& !is_init(p
))
205 /* Not swapper, init nor kernel thread */
210 static void sysrq_handle_term(int key
, struct tty_struct
*tty
)
212 send_sig_all(SIGTERM
);
213 console_loglevel
= 8;
215 static struct sysrq_key_op sysrq_term_op
= {
216 .handler
= sysrq_handle_term
,
218 .action_msg
= "Terminate All Tasks",
219 .enable_mask
= SYSRQ_ENABLE_SIGNAL
,
222 static void moom_callback(void *ignored
)
224 out_of_memory(&NODE_DATA(0)->node_zonelists
[ZONE_NORMAL
],
228 static DECLARE_WORK(moom_work
, moom_callback
, NULL
);
230 static void sysrq_handle_moom(int key
, struct tty_struct
*tty
)
232 schedule_work(&moom_work
);
234 static struct sysrq_key_op sysrq_moom_op
= {
235 .handler
= sysrq_handle_moom
,
237 .action_msg
= "Manual OOM execution",
240 static void sysrq_handle_kill(int key
, struct tty_struct
*tty
)
242 send_sig_all(SIGKILL
);
243 console_loglevel
= 8;
245 static struct sysrq_key_op sysrq_kill_op
= {
246 .handler
= sysrq_handle_kill
,
248 .action_msg
= "Kill All Tasks",
249 .enable_mask
= SYSRQ_ENABLE_SIGNAL
,
252 static void sysrq_handle_unrt(int key
, struct tty_struct
*tty
)
254 normalize_rt_tasks();
256 static struct sysrq_key_op sysrq_unrt_op
= {
257 .handler
= sysrq_handle_unrt
,
259 .action_msg
= "Nice All RT Tasks",
260 .enable_mask
= SYSRQ_ENABLE_RTNICE
,
263 /* Key Operations table and lock */
264 static DEFINE_SPINLOCK(sysrq_key_table_lock
);
266 static struct sysrq_key_op
*sysrq_key_table
[36] = {
267 &sysrq_loglevel_op
, /* 0 */
268 &sysrq_loglevel_op
, /* 1 */
269 &sysrq_loglevel_op
, /* 2 */
270 &sysrq_loglevel_op
, /* 3 */
271 &sysrq_loglevel_op
, /* 4 */
272 &sysrq_loglevel_op
, /* 5 */
273 &sysrq_loglevel_op
, /* 6 */
274 &sysrq_loglevel_op
, /* 7 */
275 &sysrq_loglevel_op
, /* 8 */
276 &sysrq_loglevel_op
, /* 9 */
279 * Don't use for system provided sysrqs, it is handled specially on
280 * sparc and will never arrive
283 &sysrq_reboot_op
, /* b */
284 &sysrq_crashdump_op
, /* c */
285 &sysrq_showlocks_op
, /* d */
286 &sysrq_term_op
, /* e */
287 &sysrq_moom_op
, /* f */
290 &sysrq_kill_op
, /* i */
292 &sysrq_SAK_op
, /* k */
294 &sysrq_showmem_op
, /* m */
295 &sysrq_unrt_op
, /* n */
296 /* This will often be registered as 'Off' at init time */
298 &sysrq_showregs_op
, /* p */
300 &sysrq_unraw_op
, /* r */
301 &sysrq_sync_op
, /* s */
302 &sysrq_showstate_op
, /* t */
303 &sysrq_mountro_op
, /* u */
304 /* May be assigned at init time by SMP VOYAGER */
312 /* key2index calculation, -1 on invalid index */
313 static int sysrq_key_table_key2index(int key
)
317 if ((key
>= '0') && (key
<= '9'))
319 else if ((key
>= 'a') && (key
<= 'z'))
320 retval
= key
+ 10 - 'a';
327 * get and put functions for the table, exposed to modules.
329 struct sysrq_key_op
*__sysrq_get_key_op(int key
)
331 struct sysrq_key_op
*op_p
= NULL
;
334 i
= sysrq_key_table_key2index(key
);
336 op_p
= sysrq_key_table
[i
];
340 static void __sysrq_put_key_op(int key
, struct sysrq_key_op
*op_p
)
342 int i
= sysrq_key_table_key2index(key
);
345 sysrq_key_table
[i
] = op_p
;
349 * This is the non-locking version of handle_sysrq. It must/can only be called
350 * by sysrq key handlers, as they are inside of the lock
352 void __handle_sysrq(int key
, struct tty_struct
*tty
, int check_mask
)
354 struct sysrq_key_op
*op_p
;
359 spin_lock_irqsave(&sysrq_key_table_lock
, flags
);
360 orig_log_level
= console_loglevel
;
361 console_loglevel
= 7;
362 printk(KERN_INFO
"SysRq : ");
364 op_p
= __sysrq_get_key_op(key
);
367 * Should we check for enabled operations (/proc/sysrq-trigger
368 * should not) and is the invoked operation enabled?
370 if (!check_mask
|| sysrq_enabled
== 1 ||
371 (sysrq_enabled
& op_p
->enable_mask
)) {
372 printk("%s\n", op_p
->action_msg
);
373 console_loglevel
= orig_log_level
;
374 op_p
->handler(key
, tty
);
376 printk("This sysrq operation is disabled.\n");
380 /* Only print the help msg once per handler */
381 for (i
= 0; i
< ARRAY_SIZE(sysrq_key_table
); i
++) {
382 if (sysrq_key_table
[i
]) {
385 for (j
= 0; sysrq_key_table
[i
] !=
386 sysrq_key_table
[j
]; j
++)
390 printk("%s ", sysrq_key_table
[i
]->help_msg
);
394 console_loglevel
= orig_log_level
;
396 spin_unlock_irqrestore(&sysrq_key_table_lock
, flags
);
400 * This function is called by the keyboard handler when SysRq is pressed
401 * and any other keycode arrives.
403 void handle_sysrq(int key
, struct tty_struct
*tty
)
407 __handle_sysrq(key
, tty
, 1);
409 EXPORT_SYMBOL(handle_sysrq
);
411 static int __sysrq_swap_key_ops(int key
, struct sysrq_key_op
*insert_op_p
,
412 struct sysrq_key_op
*remove_op_p
)
418 spin_lock_irqsave(&sysrq_key_table_lock
, flags
);
419 if (__sysrq_get_key_op(key
) == remove_op_p
) {
420 __sysrq_put_key_op(key
, insert_op_p
);
425 spin_unlock_irqrestore(&sysrq_key_table_lock
, flags
);
429 int register_sysrq_key(int key
, struct sysrq_key_op
*op_p
)
431 return __sysrq_swap_key_ops(key
, op_p
, NULL
);
433 EXPORT_SYMBOL(register_sysrq_key
);
435 int unregister_sysrq_key(int key
, struct sysrq_key_op
*op_p
)
437 return __sysrq_swap_key_ops(key
, NULL
, op_p
);
439 EXPORT_SYMBOL(unregister_sysrq_key
);