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1da177e4 LT |
1 | /* -*- 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 | ||
1da177e4 LT |
15 | #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> | |
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> | |
86b1ae38 | 37 | #include <linux/kexec.h> |
7d12e780 | 38 | #include <linux/irq.h> |
1da177e4 LT |
39 | |
40 | #include <asm/ptrace.h> | |
2033b0c3 | 41 | #include <asm/irq_regs.h> |
1da177e4 LT |
42 | |
43 | /* Whether we react on sysrq keys or just ignore them */ | |
5d6f647f IM |
44 | int __read_mostly __sysrq_enabled = 1; |
45 | ||
46 | static int __read_mostly sysrq_always_enabled; | |
47 | ||
48 | int sysrq_on(void) | |
49 | { | |
50 | return __sysrq_enabled || sysrq_always_enabled; | |
51 | } | |
52 | ||
53 | /* | |
54 | * A value of 1 means 'all', other nonzero values are an op mask: | |
55 | */ | |
56 | static inline int sysrq_on_mask(int mask) | |
57 | { | |
58 | return sysrq_always_enabled || __sysrq_enabled == 1 || | |
59 | (__sysrq_enabled & mask); | |
60 | } | |
61 | ||
62 | static int __init sysrq_always_enabled_setup(char *str) | |
63 | { | |
64 | sysrq_always_enabled = 1; | |
65 | printk(KERN_INFO "debug: sysrq always enabled.\n"); | |
66 | ||
67 | return 1; | |
68 | } | |
69 | ||
70 | __setup("sysrq_always_enabled", sysrq_always_enabled_setup); | |
71 | ||
1da177e4 | 72 | |
7d12e780 | 73 | static void sysrq_handle_loglevel(int key, struct tty_struct *tty) |
1da177e4 LT |
74 | { |
75 | int i; | |
76 | i = key - '0'; | |
77 | console_loglevel = 7; | |
78 | printk("Loglevel set to %d\n", i); | |
79 | console_loglevel = i; | |
bf36b901 | 80 | } |
1da177e4 LT |
81 | static struct sysrq_key_op sysrq_loglevel_op = { |
82 | .handler = sysrq_handle_loglevel, | |
83 | .help_msg = "loglevel0-8", | |
84 | .action_msg = "Changing Loglevel", | |
85 | .enable_mask = SYSRQ_ENABLE_LOG, | |
86 | }; | |
87 | ||
1da177e4 | 88 | #ifdef CONFIG_VT |
7d12e780 | 89 | static void sysrq_handle_SAK(int key, struct tty_struct *tty) |
1da177e4 LT |
90 | { |
91 | if (tty) | |
92 | do_SAK(tty); | |
93 | reset_vc(vc_cons[fg_console].d); | |
94 | } | |
95 | static 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 | }; | |
bf36b901 AM |
101 | #else |
102 | #define sysrq_SAK_op (*(struct sysrq_key_op *)0) | |
1da177e4 LT |
103 | #endif |
104 | ||
105 | #ifdef CONFIG_VT | |
7d12e780 | 106 | static void sysrq_handle_unraw(int key, struct tty_struct *tty) |
1da177e4 LT |
107 | { |
108 | struct kbd_struct *kbd = &kbd_table[fg_console]; | |
109 | ||
110 | if (kbd) | |
111 | kbd->kbdmode = VC_XLATE; | |
112 | } | |
113 | static struct sysrq_key_op sysrq_unraw_op = { | |
114 | .handler = sysrq_handle_unraw, | |
115 | .help_msg = "unRaw", | |
116 | .action_msg = "Keyboard mode set to XLATE", | |
117 | .enable_mask = SYSRQ_ENABLE_KEYBOARD, | |
118 | }; | |
bf36b901 AM |
119 | #else |
120 | #define sysrq_unraw_op (*(struct sysrq_key_op *)0) | |
1da177e4 LT |
121 | #endif /* CONFIG_VT */ |
122 | ||
86b1ae38 | 123 | #ifdef CONFIG_KEXEC |
7d12e780 | 124 | static void sysrq_handle_crashdump(int key, struct tty_struct *tty) |
86b1ae38 | 125 | { |
7d12e780 | 126 | crash_kexec(get_irq_regs()); |
86b1ae38 HN |
127 | } |
128 | static 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 | }; | |
bf36b901 AM |
134 | #else |
135 | #define sysrq_crashdump_op (*(struct sysrq_key_op *)0) | |
86b1ae38 HN |
136 | #endif |
137 | ||
7d12e780 | 138 | static void sysrq_handle_reboot(int key, struct tty_struct *tty) |
1da177e4 | 139 | { |
b2e9c7d0 | 140 | lockdep_off(); |
1da177e4 | 141 | local_irq_enable(); |
4de8b9b7 | 142 | emergency_restart(); |
1da177e4 | 143 | } |
1da177e4 LT |
144 | static 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 | ||
7d12e780 | 151 | static void sysrq_handle_sync(int key, struct tty_struct *tty) |
1da177e4 LT |
152 | { |
153 | emergency_sync(); | |
154 | } | |
1da177e4 LT |
155 | static 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 | ||
7d12e780 | 162 | static void sysrq_handle_mountro(int key, struct tty_struct *tty) |
1da177e4 LT |
163 | { |
164 | emergency_remount(); | |
165 | } | |
1da177e4 LT |
166 | static struct sysrq_key_op sysrq_mountro_op = { |
167 | .handler = sysrq_handle_mountro, | |
168 | .help_msg = "Unmount", | |
169 | .action_msg = "Emergency Remount R/O", | |
170 | .enable_mask = SYSRQ_ENABLE_REMOUNT, | |
171 | }; | |
172 | ||
8c64580d | 173 | #ifdef CONFIG_LOCKDEP |
7d12e780 | 174 | static void sysrq_handle_showlocks(int key, struct tty_struct *tty) |
de5097c2 | 175 | { |
9a11b49a | 176 | debug_show_all_locks(); |
de5097c2 | 177 | } |
8c64580d | 178 | |
de5097c2 IM |
179 | static struct sysrq_key_op sysrq_showlocks_op = { |
180 | .handler = sysrq_handle_showlocks, | |
181 | .help_msg = "show-all-locks(D)", | |
182 | .action_msg = "Show Locks Held", | |
183 | }; | |
bf36b901 AM |
184 | #else |
185 | #define sysrq_showlocks_op (*(struct sysrq_key_op *)0) | |
de5097c2 | 186 | #endif |
1da177e4 | 187 | |
7d12e780 | 188 | static void sysrq_handle_showregs(int key, struct tty_struct *tty) |
1da177e4 | 189 | { |
7d12e780 DH |
190 | struct pt_regs *regs = get_irq_regs(); |
191 | if (regs) | |
192 | show_regs(regs); | |
1da177e4 LT |
193 | } |
194 | static struct sysrq_key_op sysrq_showregs_op = { | |
195 | .handler = sysrq_handle_showregs, | |
196 | .help_msg = "showPc", | |
197 | .action_msg = "Show Regs", | |
198 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
199 | }; | |
200 | ||
7d12e780 | 201 | static void sysrq_handle_showstate(int key, struct tty_struct *tty) |
1da177e4 LT |
202 | { |
203 | show_state(); | |
204 | } | |
205 | static struct sysrq_key_op sysrq_showstate_op = { | |
206 | .handler = sysrq_handle_showstate, | |
207 | .help_msg = "showTasks", | |
208 | .action_msg = "Show State", | |
209 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
210 | }; | |
211 | ||
e59e2ae2 IM |
212 | static void sysrq_handle_showstate_blocked(int key, struct tty_struct *tty) |
213 | { | |
214 | show_state_filter(TASK_UNINTERRUPTIBLE); | |
215 | } | |
216 | static struct sysrq_key_op sysrq_showstate_blocked_op = { | |
217 | .handler = sysrq_handle_showstate_blocked, | |
d346cce3 | 218 | .help_msg = "shoW-blocked-tasks", |
e59e2ae2 IM |
219 | .action_msg = "Show Blocked State", |
220 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
221 | }; | |
222 | ||
223 | ||
7d12e780 | 224 | static void sysrq_handle_showmem(int key, struct tty_struct *tty) |
1da177e4 LT |
225 | { |
226 | show_mem(); | |
227 | } | |
228 | static struct sysrq_key_op sysrq_showmem_op = { | |
229 | .handler = sysrq_handle_showmem, | |
230 | .help_msg = "showMem", | |
231 | .action_msg = "Show Memory", | |
232 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
233 | }; | |
234 | ||
bf36b901 AM |
235 | /* |
236 | * Signal sysrq helper function. Sends a signal to all user processes. | |
237 | */ | |
1da177e4 LT |
238 | static void send_sig_all(int sig) |
239 | { | |
240 | struct task_struct *p; | |
241 | ||
242 | for_each_process(p) { | |
f400e198 | 243 | if (p->mm && !is_init(p)) |
1da177e4 LT |
244 | /* Not swapper, init nor kernel thread */ |
245 | force_sig(sig, p); | |
246 | } | |
247 | } | |
248 | ||
7d12e780 | 249 | static void sysrq_handle_term(int key, struct tty_struct *tty) |
1da177e4 LT |
250 | { |
251 | send_sig_all(SIGTERM); | |
252 | console_loglevel = 8; | |
253 | } | |
254 | static struct sysrq_key_op sysrq_term_op = { | |
255 | .handler = sysrq_handle_term, | |
256 | .help_msg = "tErm", | |
257 | .action_msg = "Terminate All Tasks", | |
258 | .enable_mask = SYSRQ_ENABLE_SIGNAL, | |
259 | }; | |
260 | ||
65f27f38 | 261 | static void moom_callback(struct work_struct *ignored) |
1da177e4 | 262 | { |
bf36b901 AM |
263 | out_of_memory(&NODE_DATA(0)->node_zonelists[ZONE_NORMAL], |
264 | GFP_KERNEL, 0); | |
1da177e4 LT |
265 | } |
266 | ||
65f27f38 | 267 | static DECLARE_WORK(moom_work, moom_callback); |
1da177e4 | 268 | |
7d12e780 | 269 | static void sysrq_handle_moom(int key, struct tty_struct *tty) |
1da177e4 LT |
270 | { |
271 | schedule_work(&moom_work); | |
272 | } | |
273 | static struct sysrq_key_op sysrq_moom_op = { | |
274 | .handler = sysrq_handle_moom, | |
275 | .help_msg = "Full", | |
276 | .action_msg = "Manual OOM execution", | |
277 | }; | |
278 | ||
7d12e780 | 279 | static void sysrq_handle_kill(int key, struct tty_struct *tty) |
1da177e4 LT |
280 | { |
281 | send_sig_all(SIGKILL); | |
282 | console_loglevel = 8; | |
283 | } | |
284 | static struct sysrq_key_op sysrq_kill_op = { | |
285 | .handler = sysrq_handle_kill, | |
286 | .help_msg = "kIll", | |
287 | .action_msg = "Kill All Tasks", | |
288 | .enable_mask = SYSRQ_ENABLE_SIGNAL, | |
289 | }; | |
290 | ||
7d12e780 | 291 | static void sysrq_handle_unrt(int key, struct tty_struct *tty) |
1da177e4 LT |
292 | { |
293 | normalize_rt_tasks(); | |
294 | } | |
295 | static struct sysrq_key_op sysrq_unrt_op = { | |
296 | .handler = sysrq_handle_unrt, | |
297 | .help_msg = "Nice", | |
298 | .action_msg = "Nice All RT Tasks", | |
299 | .enable_mask = SYSRQ_ENABLE_RTNICE, | |
300 | }; | |
301 | ||
302 | /* Key Operations table and lock */ | |
303 | static DEFINE_SPINLOCK(sysrq_key_table_lock); | |
bf36b901 AM |
304 | |
305 | static struct sysrq_key_op *sysrq_key_table[36] = { | |
306 | &sysrq_loglevel_op, /* 0 */ | |
307 | &sysrq_loglevel_op, /* 1 */ | |
308 | &sysrq_loglevel_op, /* 2 */ | |
309 | &sysrq_loglevel_op, /* 3 */ | |
310 | &sysrq_loglevel_op, /* 4 */ | |
311 | &sysrq_loglevel_op, /* 5 */ | |
312 | &sysrq_loglevel_op, /* 6 */ | |
313 | &sysrq_loglevel_op, /* 7 */ | |
314 | &sysrq_loglevel_op, /* 8 */ | |
315 | &sysrq_loglevel_op, /* 9 */ | |
316 | ||
317 | /* | |
d346cce3 RD |
318 | * a: Don't use for system provided sysrqs, it is handled specially on |
319 | * sparc and will never arrive. | |
bf36b901 AM |
320 | */ |
321 | NULL, /* a */ | |
322 | &sysrq_reboot_op, /* b */ | |
d346cce3 | 323 | &sysrq_crashdump_op, /* c & ibm_emac driver debug */ |
bf36b901 AM |
324 | &sysrq_showlocks_op, /* d */ |
325 | &sysrq_term_op, /* e */ | |
326 | &sysrq_moom_op, /* f */ | |
d346cce3 | 327 | /* g: May be registered by ppc for kgdb */ |
bf36b901 AM |
328 | NULL, /* g */ |
329 | NULL, /* h */ | |
330 | &sysrq_kill_op, /* i */ | |
331 | NULL, /* j */ | |
332 | &sysrq_SAK_op, /* k */ | |
333 | NULL, /* l */ | |
334 | &sysrq_showmem_op, /* m */ | |
335 | &sysrq_unrt_op, /* n */ | |
d346cce3 | 336 | /* o: This will often be registered as 'Off' at init time */ |
bf36b901 AM |
337 | NULL, /* o */ |
338 | &sysrq_showregs_op, /* p */ | |
339 | NULL, /* q */ | |
d346cce3 | 340 | &sysrq_unraw_op, /* r */ |
bf36b901 AM |
341 | &sysrq_sync_op, /* s */ |
342 | &sysrq_showstate_op, /* t */ | |
343 | &sysrq_mountro_op, /* u */ | |
d346cce3 | 344 | /* v: May be registered at init time by SMP VOYAGER */ |
bf36b901 | 345 | NULL, /* v */ |
d346cce3 RD |
346 | &sysrq_showstate_blocked_op, /* w */ |
347 | /* x: May be registered on ppc/powerpc for xmon */ | |
348 | NULL, /* x */ | |
bf36b901 AM |
349 | NULL, /* y */ |
350 | NULL /* z */ | |
1da177e4 LT |
351 | }; |
352 | ||
353 | /* key2index calculation, -1 on invalid index */ | |
bf36b901 AM |
354 | static int sysrq_key_table_key2index(int key) |
355 | { | |
1da177e4 | 356 | int retval; |
bf36b901 AM |
357 | |
358 | if ((key >= '0') && (key <= '9')) | |
1da177e4 | 359 | retval = key - '0'; |
bf36b901 | 360 | else if ((key >= 'a') && (key <= 'z')) |
1da177e4 | 361 | retval = key + 10 - 'a'; |
bf36b901 | 362 | else |
1da177e4 | 363 | retval = -1; |
1da177e4 LT |
364 | return retval; |
365 | } | |
366 | ||
367 | /* | |
368 | * get and put functions for the table, exposed to modules. | |
369 | */ | |
bf36b901 AM |
370 | struct sysrq_key_op *__sysrq_get_key_op(int key) |
371 | { | |
372 | struct sysrq_key_op *op_p = NULL; | |
1da177e4 | 373 | int i; |
bf36b901 | 374 | |
1da177e4 | 375 | i = sysrq_key_table_key2index(key); |
bf36b901 AM |
376 | if (i != -1) |
377 | op_p = sysrq_key_table[i]; | |
1da177e4 LT |
378 | return op_p; |
379 | } | |
380 | ||
bf36b901 AM |
381 | static void __sysrq_put_key_op(int key, struct sysrq_key_op *op_p) |
382 | { | |
383 | int i = sysrq_key_table_key2index(key); | |
1da177e4 | 384 | |
1da177e4 LT |
385 | if (i != -1) |
386 | sysrq_key_table[i] = op_p; | |
387 | } | |
388 | ||
389 | /* | |
bf36b901 AM |
390 | * This is the non-locking version of handle_sysrq. It must/can only be called |
391 | * by sysrq key handlers, as they are inside of the lock | |
1da177e4 | 392 | */ |
7d12e780 | 393 | void __handle_sysrq(int key, struct tty_struct *tty, int check_mask) |
1da177e4 LT |
394 | { |
395 | struct sysrq_key_op *op_p; | |
396 | int orig_log_level; | |
bf36b901 | 397 | int i; |
1da177e4 LT |
398 | unsigned long flags; |
399 | ||
400 | spin_lock_irqsave(&sysrq_key_table_lock, flags); | |
401 | orig_log_level = console_loglevel; | |
402 | console_loglevel = 7; | |
403 | printk(KERN_INFO "SysRq : "); | |
404 | ||
405 | op_p = __sysrq_get_key_op(key); | |
406 | if (op_p) { | |
bf36b901 AM |
407 | /* |
408 | * Should we check for enabled operations (/proc/sysrq-trigger | |
409 | * should not) and is the invoked operation enabled? | |
410 | */ | |
5d6f647f | 411 | if (!check_mask || sysrq_on_mask(op_p->enable_mask)) { |
bf36b901 | 412 | printk("%s\n", op_p->action_msg); |
1da177e4 | 413 | console_loglevel = orig_log_level; |
7d12e780 | 414 | op_p->handler(key, tty); |
bf36b901 | 415 | } else { |
1da177e4 | 416 | printk("This sysrq operation is disabled.\n"); |
bf36b901 | 417 | } |
1da177e4 LT |
418 | } else { |
419 | printk("HELP : "); | |
420 | /* Only print the help msg once per handler */ | |
bf36b901 AM |
421 | for (i = 0; i < ARRAY_SIZE(sysrq_key_table); i++) { |
422 | if (sysrq_key_table[i]) { | |
423 | int j; | |
424 | ||
425 | for (j = 0; sysrq_key_table[i] != | |
426 | sysrq_key_table[j]; j++) | |
427 | ; | |
428 | if (j != i) | |
429 | continue; | |
430 | printk("%s ", sysrq_key_table[i]->help_msg); | |
431 | } | |
1da177e4 | 432 | } |
bf36b901 | 433 | printk("\n"); |
1da177e4 LT |
434 | console_loglevel = orig_log_level; |
435 | } | |
436 | spin_unlock_irqrestore(&sysrq_key_table_lock, flags); | |
437 | } | |
438 | ||
439 | /* | |
440 | * This function is called by the keyboard handler when SysRq is pressed | |
441 | * and any other keycode arrives. | |
442 | */ | |
7d12e780 | 443 | void handle_sysrq(int key, struct tty_struct *tty) |
1da177e4 | 444 | { |
5d6f647f IM |
445 | if (sysrq_on()) |
446 | __handle_sysrq(key, tty, 1); | |
1da177e4 | 447 | } |
bf36b901 | 448 | EXPORT_SYMBOL(handle_sysrq); |
1da177e4 | 449 | |
cf62ddce | 450 | static int __sysrq_swap_key_ops(int key, struct sysrq_key_op *insert_op_p, |
bf36b901 AM |
451 | struct sysrq_key_op *remove_op_p) |
452 | { | |
1da177e4 LT |
453 | |
454 | int retval; | |
455 | unsigned long flags; | |
456 | ||
457 | spin_lock_irqsave(&sysrq_key_table_lock, flags); | |
458 | if (__sysrq_get_key_op(key) == remove_op_p) { | |
459 | __sysrq_put_key_op(key, insert_op_p); | |
460 | retval = 0; | |
461 | } else { | |
462 | retval = -1; | |
463 | } | |
464 | spin_unlock_irqrestore(&sysrq_key_table_lock, flags); | |
1da177e4 LT |
465 | return retval; |
466 | } | |
467 | ||
468 | int register_sysrq_key(int key, struct sysrq_key_op *op_p) | |
469 | { | |
470 | return __sysrq_swap_key_ops(key, op_p, NULL); | |
471 | } | |
bf36b901 | 472 | EXPORT_SYMBOL(register_sysrq_key); |
1da177e4 LT |
473 | |
474 | int unregister_sysrq_key(int key, struct sysrq_key_op *op_p) | |
475 | { | |
476 | return __sysrq_swap_key_ops(key, NULL, op_p); | |
477 | } | |
1da177e4 | 478 | EXPORT_SYMBOL(unregister_sysrq_key); |