blob: de60e1ea4fb3830e01524b73381738d7e98485b6 [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/* -*- linux-c -*-
2 *
3 * $Id: sysrq.c,v 1.15 1998/08/23 14:56:41 mj Exp $
4 *
5 * Linux Magic System Request Key Hacks
6 *
7 * (c) 1997 Martin Mares <mj@atrey.karlin.mff.cuni.cz>
8 * based on ideas by Pavel Machek <pavel@atrey.karlin.mff.cuni.cz>
9 *
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
13 */
14
Linus Torvalds1da177e2005-04-16 15:20:36 -070015#include <linux/sched.h>
16#include <linux/interrupt.h>
17#include <linux/mm.h>
18#include <linux/fs.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>
Linus Torvalds1da177e2005-04-16 15:20:36 -070027#include <linux/kernel.h>
28#include <linux/module.h>
29#include <linux/suspend.h>
30#include <linux/writeback.h>
31#include <linux/buffer_head.h> /* for fsync_bdev() */
32#include <linux/swap.h>
33#include <linux/spinlock.h>
34#include <linux/vt_kern.h>
35#include <linux/workqueue.h>
Hariprasad Nellitheertha86b1ae32005-06-25 14:58:25 -070036#include <linux/kexec.h>
David Howells7d12e782006-10-05 14:55:46 +010037#include <linux/irq.h>
Ingo Molnar88ad0bf62007-02-16 01:28:16 -080038#include <linux/hrtimer.h>
David Rientjes5a3135c22007-10-16 23:25:53 -070039#include <linux/oom.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070040
41#include <asm/ptrace.h>
Heiko Carstens2033b0c2006-10-06 16:38:42 +020042#include <asm/irq_regs.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070043
44/* Whether we react on sysrq keys or just ignore them */
Ingo Molnar5d6f6472006-12-13 00:34:36 -080045int __read_mostly __sysrq_enabled = 1;
46
47static int __read_mostly sysrq_always_enabled;
48
49int sysrq_on(void)
50{
51 return __sysrq_enabled || sysrq_always_enabled;
52}
53
54/*
55 * A value of 1 means 'all', other nonzero values are an op mask:
56 */
57static inline int sysrq_on_mask(int mask)
58{
59 return sysrq_always_enabled || __sysrq_enabled == 1 ||
60 (__sysrq_enabled & mask);
61}
62
63static int __init sysrq_always_enabled_setup(char *str)
64{
65 sysrq_always_enabled = 1;
66 printk(KERN_INFO "debug: sysrq always enabled.\n");
67
68 return 1;
69}
70
71__setup("sysrq_always_enabled", sysrq_always_enabled_setup);
72
Linus Torvalds1da177e2005-04-16 15:20:36 -070073
David Howells7d12e782006-10-05 14:55:46 +010074static void sysrq_handle_loglevel(int key, struct tty_struct *tty)
Linus Torvalds1da177e2005-04-16 15:20:36 -070075{
76 int i;
77 i = key - '0';
78 console_loglevel = 7;
79 printk("Loglevel set to %d\n", i);
80 console_loglevel = i;
Andrew Mortonbf36b902006-03-25 03:07:08 -080081}
Linus Torvalds1da177e2005-04-16 15:20:36 -070082static struct sysrq_key_op sysrq_loglevel_op = {
83 .handler = sysrq_handle_loglevel,
84 .help_msg = "loglevel0-8",
85 .action_msg = "Changing Loglevel",
86 .enable_mask = SYSRQ_ENABLE_LOG,
87};
88
Linus Torvalds1da177e2005-04-16 15:20:36 -070089#ifdef CONFIG_VT
David Howells7d12e782006-10-05 14:55:46 +010090static void sysrq_handle_SAK(int key, struct tty_struct *tty)
Linus Torvalds1da177e2005-04-16 15:20:36 -070091{
Eric W. Biederman8b6312f2007-02-10 01:44:34 -080092 struct work_struct *SAK_work = &vc_cons[fg_console].SAK_work;
Eric W. Biederman8b6312f2007-02-10 01:44:34 -080093 schedule_work(SAK_work);
Linus Torvalds1da177e2005-04-16 15:20:36 -070094}
95static struct sysrq_key_op sysrq_SAK_op = {
96 .handler = sysrq_handle_SAK,
97 .help_msg = "saK",
98 .action_msg = "SAK",
99 .enable_mask = SYSRQ_ENABLE_KEYBOARD,
100};
Andrew Mortonbf36b902006-03-25 03:07:08 -0800101#else
102#define sysrq_SAK_op (*(struct sysrq_key_op *)0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700103#endif
104
105#ifdef CONFIG_VT
David Howells7d12e782006-10-05 14:55:46 +0100106static void sysrq_handle_unraw(int key, struct tty_struct *tty)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700107{
108 struct kbd_struct *kbd = &kbd_table[fg_console];
109
110 if (kbd)
Bill Nottingham2e8ecb92007-10-16 23:29:38 -0700111 kbd->kbdmode = default_utf8 ? VC_UNICODE : VC_XLATE;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700112}
113static struct sysrq_key_op sysrq_unraw_op = {
114 .handler = sysrq_handle_unraw,
115 .help_msg = "unRaw",
Bill Nottingham2e8ecb92007-10-16 23:29:38 -0700116 .action_msg = "Keyboard mode set to system default",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700117 .enable_mask = SYSRQ_ENABLE_KEYBOARD,
118};
Andrew Mortonbf36b902006-03-25 03:07:08 -0800119#else
120#define sysrq_unraw_op (*(struct sysrq_key_op *)0)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700121#endif /* CONFIG_VT */
122
Hariprasad Nellitheertha86b1ae32005-06-25 14:58:25 -0700123#ifdef CONFIG_KEXEC
David Howells7d12e782006-10-05 14:55:46 +0100124static void sysrq_handle_crashdump(int key, struct tty_struct *tty)
Hariprasad Nellitheertha86b1ae32005-06-25 14:58:25 -0700125{
David Howells7d12e782006-10-05 14:55:46 +0100126 crash_kexec(get_irq_regs());
Hariprasad Nellitheertha86b1ae32005-06-25 14:58:25 -0700127}
128static struct sysrq_key_op sysrq_crashdump_op = {
129 .handler = sysrq_handle_crashdump,
130 .help_msg = "Crashdump",
131 .action_msg = "Trigger a crashdump",
132 .enable_mask = SYSRQ_ENABLE_DUMP,
133};
Andrew Mortonbf36b902006-03-25 03:07:08 -0800134#else
135#define sysrq_crashdump_op (*(struct sysrq_key_op *)0)
Hariprasad Nellitheertha86b1ae32005-06-25 14:58:25 -0700136#endif
137
David Howells7d12e782006-10-05 14:55:46 +0100138static void sysrq_handle_reboot(int key, struct tty_struct *tty)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700139{
Peter Zijlstrab2e9c7d2006-09-30 23:28:02 -0700140 lockdep_off();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141 local_irq_enable();
Eric W. Biederman4de8b9b2005-07-26 11:51:06 -0600142 emergency_restart();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700143}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700144static struct sysrq_key_op sysrq_reboot_op = {
145 .handler = sysrq_handle_reboot,
146 .help_msg = "reBoot",
147 .action_msg = "Resetting",
148 .enable_mask = SYSRQ_ENABLE_BOOT,
149};
150
David Howells7d12e782006-10-05 14:55:46 +0100151static void sysrq_handle_sync(int key, struct tty_struct *tty)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700152{
153 emergency_sync();
154}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155static struct sysrq_key_op sysrq_sync_op = {
156 .handler = sysrq_handle_sync,
157 .help_msg = "Sync",
158 .action_msg = "Emergency Sync",
159 .enable_mask = SYSRQ_ENABLE_SYNC,
160};
161
Ingo Molnar88ad0bf62007-02-16 01:28:16 -0800162static void sysrq_handle_show_timers(int key, struct tty_struct *tty)
163{
164 sysrq_timer_list_show();
165}
166
167static struct sysrq_key_op sysrq_show_timers_op = {
168 .handler = sysrq_handle_show_timers,
169 .help_msg = "show-all-timers(Q)",
170 .action_msg = "Show Pending Timers",
171};
172
David Howells7d12e782006-10-05 14:55:46 +0100173static void sysrq_handle_mountro(int key, struct tty_struct *tty)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700174{
175 emergency_remount();
176}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700177static struct sysrq_key_op sysrq_mountro_op = {
178 .handler = sysrq_handle_mountro,
179 .help_msg = "Unmount",
180 .action_msg = "Emergency Remount R/O",
181 .enable_mask = SYSRQ_ENABLE_REMOUNT,
182};
183
Ingo Molnar8c645802006-07-03 00:24:56 -0700184#ifdef CONFIG_LOCKDEP
David Howells7d12e782006-10-05 14:55:46 +0100185static void sysrq_handle_showlocks(int key, struct tty_struct *tty)
Ingo Molnarde5097c2006-01-09 15:59:21 -0800186{
Ingo Molnar9a11b49a2006-07-03 00:24:33 -0700187 debug_show_all_locks();
Ingo Molnarde5097c2006-01-09 15:59:21 -0800188}
Ingo Molnar8c645802006-07-03 00:24:56 -0700189
Ingo Molnarde5097c2006-01-09 15:59:21 -0800190static struct sysrq_key_op sysrq_showlocks_op = {
191 .handler = sysrq_handle_showlocks,
192 .help_msg = "show-all-locks(D)",
193 .action_msg = "Show Locks Held",
194};
Andrew Mortonbf36b902006-03-25 03:07:08 -0800195#else
196#define sysrq_showlocks_op (*(struct sysrq_key_op *)0)
Ingo Molnarde5097c2006-01-09 15:59:21 -0800197#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700198
David Howells7d12e782006-10-05 14:55:46 +0100199static void sysrq_handle_showregs(int key, struct tty_struct *tty)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200{
David Howells7d12e782006-10-05 14:55:46 +0100201 struct pt_regs *regs = get_irq_regs();
202 if (regs)
203 show_regs(regs);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700204}
205static struct sysrq_key_op sysrq_showregs_op = {
206 .handler = sysrq_handle_showregs,
207 .help_msg = "showPc",
208 .action_msg = "Show Regs",
209 .enable_mask = SYSRQ_ENABLE_DUMP,
210};
211
David Howells7d12e782006-10-05 14:55:46 +0100212static void sysrq_handle_showstate(int key, struct tty_struct *tty)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700213{
214 show_state();
215}
216static struct sysrq_key_op sysrq_showstate_op = {
217 .handler = sysrq_handle_showstate,
218 .help_msg = "showTasks",
219 .action_msg = "Show State",
220 .enable_mask = SYSRQ_ENABLE_DUMP,
221};
222
Ingo Molnare59e2ae2006-12-06 20:35:59 -0800223static void sysrq_handle_showstate_blocked(int key, struct tty_struct *tty)
224{
225 show_state_filter(TASK_UNINTERRUPTIBLE);
226}
227static struct sysrq_key_op sysrq_showstate_blocked_op = {
228 .handler = sysrq_handle_showstate_blocked,
Randy Dunlapd346cce2007-01-31 23:48:17 -0800229 .help_msg = "shoW-blocked-tasks",
Ingo Molnare59e2ae2006-12-06 20:35:59 -0800230 .action_msg = "Show Blocked State",
231 .enable_mask = SYSRQ_ENABLE_DUMP,
232};
233
234
David Howells7d12e782006-10-05 14:55:46 +0100235static void sysrq_handle_showmem(int key, struct tty_struct *tty)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700236{
237 show_mem();
238}
239static struct sysrq_key_op sysrq_showmem_op = {
240 .handler = sysrq_handle_showmem,
241 .help_msg = "showMem",
242 .action_msg = "Show Memory",
243 .enable_mask = SYSRQ_ENABLE_DUMP,
244};
245
Andrew Mortonbf36b902006-03-25 03:07:08 -0800246/*
247 * Signal sysrq helper function. Sends a signal to all user processes.
248 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700249static void send_sig_all(int sig)
250{
251 struct task_struct *p;
252
253 for_each_process(p) {
Serge E. Hallynb460cbc2007-10-18 23:39:52 -0700254 if (p->mm && !is_global_init(p))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700255 /* Not swapper, init nor kernel thread */
256 force_sig(sig, p);
257 }
258}
259
David Howells7d12e782006-10-05 14:55:46 +0100260static void sysrq_handle_term(int key, struct tty_struct *tty)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700261{
262 send_sig_all(SIGTERM);
263 console_loglevel = 8;
264}
265static struct sysrq_key_op sysrq_term_op = {
266 .handler = sysrq_handle_term,
267 .help_msg = "tErm",
268 .action_msg = "Terminate All Tasks",
269 .enable_mask = SYSRQ_ENABLE_SIGNAL,
270};
271
David Howells65f27f32006-11-22 14:55:48 +0000272static void moom_callback(struct work_struct *ignored)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700273{
Andrew Mortonbf36b902006-03-25 03:07:08 -0800274 out_of_memory(&NODE_DATA(0)->node_zonelists[ZONE_NORMAL],
275 GFP_KERNEL, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700276}
277
David Howells65f27f32006-11-22 14:55:48 +0000278static DECLARE_WORK(moom_work, moom_callback);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700279
David Howells7d12e782006-10-05 14:55:46 +0100280static void sysrq_handle_moom(int key, struct tty_struct *tty)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700281{
282 schedule_work(&moom_work);
283}
284static struct sysrq_key_op sysrq_moom_op = {
285 .handler = sysrq_handle_moom,
286 .help_msg = "Full",
287 .action_msg = "Manual OOM execution",
288};
289
David Howells7d12e782006-10-05 14:55:46 +0100290static void sysrq_handle_kill(int key, struct tty_struct *tty)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700291{
292 send_sig_all(SIGKILL);
293 console_loglevel = 8;
294}
295static struct sysrq_key_op sysrq_kill_op = {
296 .handler = sysrq_handle_kill,
297 .help_msg = "kIll",
298 .action_msg = "Kill All Tasks",
299 .enable_mask = SYSRQ_ENABLE_SIGNAL,
300};
301
David Howells7d12e782006-10-05 14:55:46 +0100302static void sysrq_handle_unrt(int key, struct tty_struct *tty)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700303{
304 normalize_rt_tasks();
305}
306static struct sysrq_key_op sysrq_unrt_op = {
307 .handler = sysrq_handle_unrt,
308 .help_msg = "Nice",
309 .action_msg = "Nice All RT Tasks",
310 .enable_mask = SYSRQ_ENABLE_RTNICE,
311};
312
313/* Key Operations table and lock */
314static DEFINE_SPINLOCK(sysrq_key_table_lock);
Andrew Mortonbf36b902006-03-25 03:07:08 -0800315
316static struct sysrq_key_op *sysrq_key_table[36] = {
317 &sysrq_loglevel_op, /* 0 */
318 &sysrq_loglevel_op, /* 1 */
319 &sysrq_loglevel_op, /* 2 */
320 &sysrq_loglevel_op, /* 3 */
321 &sysrq_loglevel_op, /* 4 */
322 &sysrq_loglevel_op, /* 5 */
323 &sysrq_loglevel_op, /* 6 */
324 &sysrq_loglevel_op, /* 7 */
325 &sysrq_loglevel_op, /* 8 */
326 &sysrq_loglevel_op, /* 9 */
327
328 /*
Randy Dunlapd346cce2007-01-31 23:48:17 -0800329 * a: Don't use for system provided sysrqs, it is handled specially on
330 * sparc and will never arrive.
Andrew Mortonbf36b902006-03-25 03:07:08 -0800331 */
332 NULL, /* a */
333 &sysrq_reboot_op, /* b */
Randy Dunlapd346cce2007-01-31 23:48:17 -0800334 &sysrq_crashdump_op, /* c & ibm_emac driver debug */
Andrew Mortonbf36b902006-03-25 03:07:08 -0800335 &sysrq_showlocks_op, /* d */
336 &sysrq_term_op, /* e */
337 &sysrq_moom_op, /* f */
Randy Dunlapd346cce2007-01-31 23:48:17 -0800338 /* g: May be registered by ppc for kgdb */
Andrew Mortonbf36b902006-03-25 03:07:08 -0800339 NULL, /* g */
340 NULL, /* h */
341 &sysrq_kill_op, /* i */
342 NULL, /* j */
343 &sysrq_SAK_op, /* k */
344 NULL, /* l */
345 &sysrq_showmem_op, /* m */
346 &sysrq_unrt_op, /* n */
Randy Dunlapd346cce2007-01-31 23:48:17 -0800347 /* o: This will often be registered as 'Off' at init time */
Andrew Mortonbf36b902006-03-25 03:07:08 -0800348 NULL, /* o */
349 &sysrq_showregs_op, /* p */
Ingo Molnar88ad0bf62007-02-16 01:28:16 -0800350 &sysrq_show_timers_op, /* q */
Randy Dunlapd346cce2007-01-31 23:48:17 -0800351 &sysrq_unraw_op, /* r */
Andrew Mortonbf36b902006-03-25 03:07:08 -0800352 &sysrq_sync_op, /* s */
353 &sysrq_showstate_op, /* t */
354 &sysrq_mountro_op, /* u */
Randy Dunlapd346cce2007-01-31 23:48:17 -0800355 /* v: May be registered at init time by SMP VOYAGER */
Andrew Mortonbf36b902006-03-25 03:07:08 -0800356 NULL, /* v */
Randy Dunlapd346cce2007-01-31 23:48:17 -0800357 &sysrq_showstate_blocked_op, /* w */
358 /* x: May be registered on ppc/powerpc for xmon */
359 NULL, /* x */
Andrew Mortonbf36b902006-03-25 03:07:08 -0800360 NULL, /* y */
361 NULL /* z */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700362};
363
364/* key2index calculation, -1 on invalid index */
Andrew Mortonbf36b902006-03-25 03:07:08 -0800365static int sysrq_key_table_key2index(int key)
366{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700367 int retval;
Andrew Mortonbf36b902006-03-25 03:07:08 -0800368
369 if ((key >= '0') && (key <= '9'))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700370 retval = key - '0';
Andrew Mortonbf36b902006-03-25 03:07:08 -0800371 else if ((key >= 'a') && (key <= 'z'))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700372 retval = key + 10 - 'a';
Andrew Mortonbf36b902006-03-25 03:07:08 -0800373 else
Linus Torvalds1da177e2005-04-16 15:20:36 -0700374 retval = -1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700375 return retval;
376}
377
378/*
379 * get and put functions for the table, exposed to modules.
380 */
Andrew Mortonbf36b902006-03-25 03:07:08 -0800381struct sysrq_key_op *__sysrq_get_key_op(int key)
382{
383 struct sysrq_key_op *op_p = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700384 int i;
Andrew Mortonbf36b902006-03-25 03:07:08 -0800385
Linus Torvalds1da177e2005-04-16 15:20:36 -0700386 i = sysrq_key_table_key2index(key);
Andrew Mortonbf36b902006-03-25 03:07:08 -0800387 if (i != -1)
388 op_p = sysrq_key_table[i];
Linus Torvalds1da177e2005-04-16 15:20:36 -0700389 return op_p;
390}
391
Andrew Mortonbf36b902006-03-25 03:07:08 -0800392static void __sysrq_put_key_op(int key, struct sysrq_key_op *op_p)
393{
394 int i = sysrq_key_table_key2index(key);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700395
Linus Torvalds1da177e2005-04-16 15:20:36 -0700396 if (i != -1)
397 sysrq_key_table[i] = op_p;
398}
399
400/*
Andrew Mortonbf36b902006-03-25 03:07:08 -0800401 * This is the non-locking version of handle_sysrq. It must/can only be called
402 * by sysrq key handlers, as they are inside of the lock
Linus Torvalds1da177e2005-04-16 15:20:36 -0700403 */
David Howells7d12e782006-10-05 14:55:46 +0100404void __handle_sysrq(int key, struct tty_struct *tty, int check_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700405{
406 struct sysrq_key_op *op_p;
407 int orig_log_level;
Andrew Mortonbf36b902006-03-25 03:07:08 -0800408 int i;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700409 unsigned long flags;
410
411 spin_lock_irqsave(&sysrq_key_table_lock, flags);
412 orig_log_level = console_loglevel;
413 console_loglevel = 7;
414 printk(KERN_INFO "SysRq : ");
415
416 op_p = __sysrq_get_key_op(key);
417 if (op_p) {
Andrew Mortonbf36b902006-03-25 03:07:08 -0800418 /*
419 * Should we check for enabled operations (/proc/sysrq-trigger
420 * should not) and is the invoked operation enabled?
421 */
Ingo Molnar5d6f6472006-12-13 00:34:36 -0800422 if (!check_mask || sysrq_on_mask(op_p->enable_mask)) {
Andrew Mortonbf36b902006-03-25 03:07:08 -0800423 printk("%s\n", op_p->action_msg);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700424 console_loglevel = orig_log_level;
David Howells7d12e782006-10-05 14:55:46 +0100425 op_p->handler(key, tty);
Andrew Mortonbf36b902006-03-25 03:07:08 -0800426 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700427 printk("This sysrq operation is disabled.\n");
Andrew Mortonbf36b902006-03-25 03:07:08 -0800428 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700429 } else {
430 printk("HELP : ");
431 /* Only print the help msg once per handler */
Andrew Mortonbf36b902006-03-25 03:07:08 -0800432 for (i = 0; i < ARRAY_SIZE(sysrq_key_table); i++) {
433 if (sysrq_key_table[i]) {
434 int j;
435
436 for (j = 0; sysrq_key_table[i] !=
437 sysrq_key_table[j]; j++)
438 ;
439 if (j != i)
440 continue;
441 printk("%s ", sysrq_key_table[i]->help_msg);
442 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700443 }
Andrew Mortonbf36b902006-03-25 03:07:08 -0800444 printk("\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700445 console_loglevel = orig_log_level;
446 }
447 spin_unlock_irqrestore(&sysrq_key_table_lock, flags);
448}
449
450/*
451 * This function is called by the keyboard handler when SysRq is pressed
452 * and any other keycode arrives.
453 */
David Howells7d12e782006-10-05 14:55:46 +0100454void handle_sysrq(int key, struct tty_struct *tty)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700455{
Ingo Molnar5d6f6472006-12-13 00:34:36 -0800456 if (sysrq_on())
457 __handle_sysrq(key, tty, 1);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700458}
Andrew Mortonbf36b902006-03-25 03:07:08 -0800459EXPORT_SYMBOL(handle_sysrq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700460
Adrian Bunkcf62ddc2005-11-08 21:39:47 -0800461static int __sysrq_swap_key_ops(int key, struct sysrq_key_op *insert_op_p,
Andrew Mortonbf36b902006-03-25 03:07:08 -0800462 struct sysrq_key_op *remove_op_p)
463{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700464
465 int retval;
466 unsigned long flags;
467
468 spin_lock_irqsave(&sysrq_key_table_lock, flags);
469 if (__sysrq_get_key_op(key) == remove_op_p) {
470 __sysrq_put_key_op(key, insert_op_p);
471 retval = 0;
472 } else {
473 retval = -1;
474 }
475 spin_unlock_irqrestore(&sysrq_key_table_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700476 return retval;
477}
478
479int register_sysrq_key(int key, struct sysrq_key_op *op_p)
480{
481 return __sysrq_swap_key_ops(key, op_p, NULL);
482}
Andrew Mortonbf36b902006-03-25 03:07:08 -0800483EXPORT_SYMBOL(register_sysrq_key);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700484
485int unregister_sysrq_key(int key, struct sysrq_key_op *op_p)
486{
487 return __sysrq_swap_key_ops(key, NULL, op_p);
488}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700489EXPORT_SYMBOL(unregister_sysrq_key);