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/config.h>
16 #include <linux/sched.h>
17 #include <linux/interrupt.h>
20 #include <linux/tty.h>
21 #include <linux/mount.h>
22 #include <linux/kdev_t.h>
23 #include <linux/major.h>
24 #include <linux/reboot.h>
25 #include <linux/sysrq.h>
26 #include <linux/kbd_kern.h>
27 #include <linux/quotaops.h>
28 #include <linux/smp_lock.h>
29 #include <linux/kernel.h>
30 #include <linux/module.h>
31 #include <linux/suspend.h>
32 #include <linux/writeback.h>
33 #include <linux/buffer_head.h> /* for fsync_bdev() */
34 #include <linux/swap.h>
35 #include <linux/spinlock.h>
36 #include <linux/vt_kern.h>
37 #include <linux/workqueue.h>
38 #include <linux/kexec.h>
40 #include <asm/ptrace.h>
42 /* Whether we react on sysrq keys or just ignore them */
43 int sysrq_enabled = 1;
45 static void sysrq_handle_loglevel(int key, struct pt_regs *pt_regs,
46 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 pt_regs *pt_regs,
63 struct tty_struct *tty)
67 reset_vc(vc_cons[fg_console].d);
69 static struct sysrq_key_op sysrq_SAK_op = {
70 .handler = sysrq_handle_SAK,
73 .enable_mask = SYSRQ_ENABLE_KEYBOARD,
76 #define sysrq_SAK_op (*(struct sysrq_key_op *)0)
80 static void sysrq_handle_unraw(int key, struct pt_regs *pt_regs,
81 struct tty_struct *tty)
83 struct kbd_struct *kbd = &kbd_table[fg_console];
86 kbd->kbdmode = VC_XLATE;
88 static struct sysrq_key_op sysrq_unraw_op = {
89 .handler = sysrq_handle_unraw,
91 .action_msg = "Keyboard mode set to XLATE",
92 .enable_mask = SYSRQ_ENABLE_KEYBOARD,
95 #define sysrq_unraw_op (*(struct sysrq_key_op *)0)
96 #endif /* CONFIG_VT */
99 static void sysrq_handle_crashdump(int key, struct pt_regs *pt_regs,
100 struct tty_struct *tty)
102 crash_kexec(pt_regs);
104 static struct sysrq_key_op sysrq_crashdump_op = {
105 .handler = sysrq_handle_crashdump,
106 .help_msg = "Crashdump",
107 .action_msg = "Trigger a crashdump",
108 .enable_mask = SYSRQ_ENABLE_DUMP,
111 #define sysrq_crashdump_op (*(struct sysrq_key_op *)0)
114 static void sysrq_handle_reboot(int key, struct pt_regs *pt_regs,
115 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_DEBUG_MUTEXES
152 static void sysrq_handle_showlocks(int key, struct pt_regs *pt_regs,
153 struct tty_struct *tty)
155 mutex_debug_show_all_locks();
157 static struct sysrq_key_op sysrq_showlocks_op = {
158 .handler = sysrq_handle_showlocks,
159 .help_msg = "show-all-locks(D)",
160 .action_msg = "Show Locks Held",
163 #define sysrq_showlocks_op (*(struct sysrq_key_op *)0)
166 static void sysrq_handle_showregs(int key, struct pt_regs *pt_regs,
167 struct tty_struct *tty)
172 static struct sysrq_key_op sysrq_showregs_op = {
173 .handler = sysrq_handle_showregs,
174 .help_msg = "showPc",
175 .action_msg = "Show Regs",
176 .enable_mask = SYSRQ_ENABLE_DUMP,
179 static void sysrq_handle_showstate(int key, struct pt_regs *pt_regs,
180 struct tty_struct *tty)
184 static struct sysrq_key_op sysrq_showstate_op = {
185 .handler = sysrq_handle_showstate,
186 .help_msg = "showTasks",
187 .action_msg = "Show State",
188 .enable_mask = SYSRQ_ENABLE_DUMP,
191 static void sysrq_handle_showmem(int key, struct pt_regs *pt_regs,
192 struct tty_struct *tty)
196 static struct sysrq_key_op sysrq_showmem_op = {
197 .handler = sysrq_handle_showmem,
198 .help_msg = "showMem",
199 .action_msg = "Show Memory",
200 .enable_mask = SYSRQ_ENABLE_DUMP,
204 * Signal sysrq helper function. Sends a signal to all user processes.
206 static void send_sig_all(int sig)
208 struct task_struct *p;
210 for_each_process(p) {
211 if (p->mm && p->pid != 1)
212 /* Not swapper, init nor kernel thread */
217 static void sysrq_handle_term(int key, struct pt_regs *pt_regs,
218 struct tty_struct *tty)
220 send_sig_all(SIGTERM);
221 console_loglevel = 8;
223 static struct sysrq_key_op sysrq_term_op = {
224 .handler = sysrq_handle_term,
226 .action_msg = "Terminate All Tasks",
227 .enable_mask = SYSRQ_ENABLE_SIGNAL,
230 static void moom_callback(void *ignored)
232 out_of_memory(&NODE_DATA(0)->node_zonelists[ZONE_NORMAL],
236 static DECLARE_WORK(moom_work, moom_callback, NULL);
238 static void sysrq_handle_moom(int key, struct pt_regs *pt_regs,
239 struct tty_struct *tty)
241 schedule_work(&moom_work);
243 static struct sysrq_key_op sysrq_moom_op = {
244 .handler = sysrq_handle_moom,
246 .action_msg = "Manual OOM execution",
249 static void sysrq_handle_kill(int key, struct pt_regs *pt_regs,
250 struct tty_struct *tty)
252 send_sig_all(SIGKILL);
253 console_loglevel = 8;
255 static struct sysrq_key_op sysrq_kill_op = {
256 .handler = sysrq_handle_kill,
258 .action_msg = "Kill All Tasks",
259 .enable_mask = SYSRQ_ENABLE_SIGNAL,
262 static void sysrq_handle_unrt(int key, struct pt_regs *pt_regs,
263 struct tty_struct *tty)
265 normalize_rt_tasks();
267 static struct sysrq_key_op sysrq_unrt_op = {
268 .handler = sysrq_handle_unrt,
270 .action_msg = "Nice All RT Tasks",
271 .enable_mask = SYSRQ_ENABLE_RTNICE,
274 /* Key Operations table and lock */
275 static DEFINE_SPINLOCK(sysrq_key_table_lock);
277 static struct sysrq_key_op *sysrq_key_table[36] = {
278 &sysrq_loglevel_op, /* 0 */
279 &sysrq_loglevel_op, /* 1 */
280 &sysrq_loglevel_op, /* 2 */
281 &sysrq_loglevel_op, /* 3 */
282 &sysrq_loglevel_op, /* 4 */
283 &sysrq_loglevel_op, /* 5 */
284 &sysrq_loglevel_op, /* 6 */
285 &sysrq_loglevel_op, /* 7 */
286 &sysrq_loglevel_op, /* 8 */
287 &sysrq_loglevel_op, /* 9 */
290 * Don't use for system provided sysrqs, it is handled specially on
291 * sparc and will never arrive
294 &sysrq_reboot_op, /* b */
295 &sysrq_crashdump_op, /* c */
296 &sysrq_showlocks_op, /* d */
297 &sysrq_term_op, /* e */
298 &sysrq_moom_op, /* f */
301 &sysrq_kill_op, /* i */
303 &sysrq_SAK_op, /* k */
305 &sysrq_showmem_op, /* m */
306 &sysrq_unrt_op, /* n */
307 /* This will often be registered as 'Off' at init time */
309 &sysrq_showregs_op, /* p */
311 &sysrq_unraw_op, /* r */
312 &sysrq_sync_op, /* s */
313 &sysrq_showstate_op, /* t */
314 &sysrq_mountro_op, /* u */
315 /* May be assigned at init time by SMP VOYAGER */
323 /* key2index calculation, -1 on invalid index */
324 static int sysrq_key_table_key2index(int key)
328 if ((key >= '0') && (key <= '9'))
330 else if ((key >= 'a') && (key <= 'z'))
331 retval = key + 10 - 'a';
338 * get and put functions for the table, exposed to modules.
340 struct sysrq_key_op *__sysrq_get_key_op(int key)
342 struct sysrq_key_op *op_p = NULL;
345 i = sysrq_key_table_key2index(key);
347 op_p = sysrq_key_table[i];
351 static void __sysrq_put_key_op(int key, struct sysrq_key_op *op_p)
353 int i = sysrq_key_table_key2index(key);
356 sysrq_key_table[i] = op_p;
360 * This is the non-locking version of handle_sysrq. It must/can only be called
361 * by sysrq key handlers, as they are inside of the lock
363 void __handle_sysrq(int key, struct pt_regs *pt_regs, struct tty_struct *tty,
366 struct sysrq_key_op *op_p;
371 spin_lock_irqsave(&sysrq_key_table_lock, flags);
372 orig_log_level = console_loglevel;
373 console_loglevel = 7;
374 printk(KERN_INFO "SysRq : ");
376 op_p = __sysrq_get_key_op(key);
379 * Should we check for enabled operations (/proc/sysrq-trigger
380 * should not) and is the invoked operation enabled?
382 if (!check_mask || sysrq_enabled == 1 ||
383 (sysrq_enabled & op_p->enable_mask)) {
384 printk("%s\n", op_p->action_msg);
385 console_loglevel = orig_log_level;
386 op_p->handler(key, pt_regs, tty);
388 printk("This sysrq operation is disabled.\n");
392 /* Only print the help msg once per handler */
393 for (i = 0; i < ARRAY_SIZE(sysrq_key_table); i++) {
394 if (sysrq_key_table[i]) {
397 for (j = 0; sysrq_key_table[i] !=
398 sysrq_key_table[j]; j++)
402 printk("%s ", sysrq_key_table[i]->help_msg);
406 console_loglevel = orig_log_level;
408 spin_unlock_irqrestore(&sysrq_key_table_lock, flags);
412 * This function is called by the keyboard handler when SysRq is pressed
413 * and any other keycode arrives.
415 void handle_sysrq(int key, struct pt_regs *pt_regs, struct tty_struct *tty)
419 __handle_sysrq(key, pt_regs, tty, 1);
421 EXPORT_SYMBOL(handle_sysrq);
423 static int __sysrq_swap_key_ops(int key, struct sysrq_key_op *insert_op_p,
424 struct sysrq_key_op *remove_op_p)
430 spin_lock_irqsave(&sysrq_key_table_lock, flags);
431 if (__sysrq_get_key_op(key) == remove_op_p) {
432 __sysrq_put_key_op(key, insert_op_p);
437 spin_unlock_irqrestore(&sysrq_key_table_lock, flags);
441 int register_sysrq_key(int key, struct sysrq_key_op *op_p)
443 return __sysrq_swap_key_ops(key, op_p, NULL);
445 EXPORT_SYMBOL(register_sysrq_key);
447 int unregister_sysrq_key(int key, struct sysrq_key_op *op_p)
449 return __sysrq_swap_key_ops(key, NULL, op_p);
451 EXPORT_SYMBOL(unregister_sysrq_key);