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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> |
1da177e4 LT |
38 | |
39 | #include <asm/ptrace.h> | |
40 | ||
41 | /* Whether we react on sysrq keys or just ignore them */ | |
42 | int sysrq_enabled = 1; | |
43 | ||
1da177e4 | 44 | static void sysrq_handle_loglevel(int key, struct pt_regs *pt_regs, |
bf36b901 | 45 | struct tty_struct *tty) |
1da177e4 LT |
46 | { |
47 | int i; | |
48 | i = key - '0'; | |
49 | console_loglevel = 7; | |
50 | printk("Loglevel set to %d\n", i); | |
51 | console_loglevel = i; | |
bf36b901 | 52 | } |
1da177e4 LT |
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, | |
58 | }; | |
59 | ||
1da177e4 LT |
60 | #ifdef CONFIG_VT |
61 | static void sysrq_handle_SAK(int key, struct pt_regs *pt_regs, | |
bf36b901 | 62 | struct tty_struct *tty) |
1da177e4 LT |
63 | { |
64 | if (tty) | |
65 | do_SAK(tty); | |
66 | reset_vc(vc_cons[fg_console].d); | |
67 | } | |
68 | static struct sysrq_key_op sysrq_SAK_op = { | |
69 | .handler = sysrq_handle_SAK, | |
70 | .help_msg = "saK", | |
71 | .action_msg = "SAK", | |
72 | .enable_mask = SYSRQ_ENABLE_KEYBOARD, | |
73 | }; | |
bf36b901 AM |
74 | #else |
75 | #define sysrq_SAK_op (*(struct sysrq_key_op *)0) | |
1da177e4 LT |
76 | #endif |
77 | ||
78 | #ifdef CONFIG_VT | |
1da177e4 | 79 | static void sysrq_handle_unraw(int key, struct pt_regs *pt_regs, |
bf36b901 | 80 | struct tty_struct *tty) |
1da177e4 LT |
81 | { |
82 | struct kbd_struct *kbd = &kbd_table[fg_console]; | |
83 | ||
84 | if (kbd) | |
85 | kbd->kbdmode = VC_XLATE; | |
86 | } | |
87 | static struct sysrq_key_op sysrq_unraw_op = { | |
88 | .handler = sysrq_handle_unraw, | |
89 | .help_msg = "unRaw", | |
90 | .action_msg = "Keyboard mode set to XLATE", | |
91 | .enable_mask = SYSRQ_ENABLE_KEYBOARD, | |
92 | }; | |
bf36b901 AM |
93 | #else |
94 | #define sysrq_unraw_op (*(struct sysrq_key_op *)0) | |
1da177e4 LT |
95 | #endif /* CONFIG_VT */ |
96 | ||
86b1ae38 | 97 | #ifdef CONFIG_KEXEC |
86b1ae38 HN |
98 | static void sysrq_handle_crashdump(int key, struct pt_regs *pt_regs, |
99 | struct tty_struct *tty) | |
100 | { | |
6e274d14 | 101 | crash_kexec(pt_regs); |
86b1ae38 HN |
102 | } |
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, | |
108 | }; | |
bf36b901 AM |
109 | #else |
110 | #define sysrq_crashdump_op (*(struct sysrq_key_op *)0) | |
86b1ae38 HN |
111 | #endif |
112 | ||
1da177e4 | 113 | static void sysrq_handle_reboot(int key, struct pt_regs *pt_regs, |
bf36b901 | 114 | struct tty_struct *tty) |
1da177e4 LT |
115 | { |
116 | local_irq_enable(); | |
4de8b9b7 | 117 | emergency_restart(); |
1da177e4 | 118 | } |
1da177e4 LT |
119 | static struct sysrq_key_op sysrq_reboot_op = { |
120 | .handler = sysrq_handle_reboot, | |
121 | .help_msg = "reBoot", | |
122 | .action_msg = "Resetting", | |
123 | .enable_mask = SYSRQ_ENABLE_BOOT, | |
124 | }; | |
125 | ||
126 | static void sysrq_handle_sync(int key, struct pt_regs *pt_regs, | |
bf36b901 | 127 | struct tty_struct *tty) |
1da177e4 LT |
128 | { |
129 | emergency_sync(); | |
130 | } | |
1da177e4 LT |
131 | static struct sysrq_key_op sysrq_sync_op = { |
132 | .handler = sysrq_handle_sync, | |
133 | .help_msg = "Sync", | |
134 | .action_msg = "Emergency Sync", | |
135 | .enable_mask = SYSRQ_ENABLE_SYNC, | |
136 | }; | |
137 | ||
138 | static void sysrq_handle_mountro(int key, struct pt_regs *pt_regs, | |
bf36b901 | 139 | struct tty_struct *tty) |
1da177e4 LT |
140 | { |
141 | emergency_remount(); | |
142 | } | |
1da177e4 LT |
143 | static struct sysrq_key_op sysrq_mountro_op = { |
144 | .handler = sysrq_handle_mountro, | |
145 | .help_msg = "Unmount", | |
146 | .action_msg = "Emergency Remount R/O", | |
147 | .enable_mask = SYSRQ_ENABLE_REMOUNT, | |
148 | }; | |
149 | ||
de5097c2 | 150 | #ifdef CONFIG_DEBUG_MUTEXES |
bf36b901 AM |
151 | static void sysrq_handle_showlocks(int key, struct pt_regs *pt_regs, |
152 | struct tty_struct *tty) | |
de5097c2 | 153 | { |
9a11b49a | 154 | debug_show_all_locks(); |
de5097c2 | 155 | } |
de5097c2 IM |
156 | static struct sysrq_key_op sysrq_showlocks_op = { |
157 | .handler = sysrq_handle_showlocks, | |
158 | .help_msg = "show-all-locks(D)", | |
159 | .action_msg = "Show Locks Held", | |
160 | }; | |
bf36b901 AM |
161 | #else |
162 | #define sysrq_showlocks_op (*(struct sysrq_key_op *)0) | |
de5097c2 | 163 | #endif |
1da177e4 | 164 | |
1da177e4 | 165 | static void sysrq_handle_showregs(int key, struct pt_regs *pt_regs, |
bf36b901 | 166 | struct tty_struct *tty) |
1da177e4 LT |
167 | { |
168 | if (pt_regs) | |
169 | show_regs(pt_regs); | |
170 | } | |
171 | static struct sysrq_key_op sysrq_showregs_op = { | |
172 | .handler = sysrq_handle_showregs, | |
173 | .help_msg = "showPc", | |
174 | .action_msg = "Show Regs", | |
175 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
176 | }; | |
177 | ||
1da177e4 | 178 | static void sysrq_handle_showstate(int key, struct pt_regs *pt_regs, |
bf36b901 | 179 | struct tty_struct *tty) |
1da177e4 LT |
180 | { |
181 | show_state(); | |
182 | } | |
183 | static struct sysrq_key_op sysrq_showstate_op = { | |
184 | .handler = sysrq_handle_showstate, | |
185 | .help_msg = "showTasks", | |
186 | .action_msg = "Show State", | |
187 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
188 | }; | |
189 | ||
1da177e4 | 190 | static void sysrq_handle_showmem(int key, struct pt_regs *pt_regs, |
bf36b901 | 191 | struct tty_struct *tty) |
1da177e4 LT |
192 | { |
193 | show_mem(); | |
194 | } | |
195 | static struct sysrq_key_op sysrq_showmem_op = { | |
196 | .handler = sysrq_handle_showmem, | |
197 | .help_msg = "showMem", | |
198 | .action_msg = "Show Memory", | |
199 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
200 | }; | |
201 | ||
bf36b901 AM |
202 | /* |
203 | * Signal sysrq helper function. Sends a signal to all user processes. | |
204 | */ | |
1da177e4 LT |
205 | static void send_sig_all(int sig) |
206 | { | |
207 | struct task_struct *p; | |
208 | ||
209 | for_each_process(p) { | |
210 | if (p->mm && p->pid != 1) | |
211 | /* Not swapper, init nor kernel thread */ | |
212 | force_sig(sig, p); | |
213 | } | |
214 | } | |
215 | ||
216 | static void sysrq_handle_term(int key, struct pt_regs *pt_regs, | |
bf36b901 | 217 | struct tty_struct *tty) |
1da177e4 LT |
218 | { |
219 | send_sig_all(SIGTERM); | |
220 | console_loglevel = 8; | |
221 | } | |
222 | static struct sysrq_key_op sysrq_term_op = { | |
223 | .handler = sysrq_handle_term, | |
224 | .help_msg = "tErm", | |
225 | .action_msg = "Terminate All Tasks", | |
226 | .enable_mask = SYSRQ_ENABLE_SIGNAL, | |
227 | }; | |
228 | ||
229 | static void moom_callback(void *ignored) | |
230 | { | |
bf36b901 AM |
231 | out_of_memory(&NODE_DATA(0)->node_zonelists[ZONE_NORMAL], |
232 | GFP_KERNEL, 0); | |
1da177e4 LT |
233 | } |
234 | ||
235 | static DECLARE_WORK(moom_work, moom_callback, NULL); | |
236 | ||
237 | static void sysrq_handle_moom(int key, struct pt_regs *pt_regs, | |
238 | struct tty_struct *tty) | |
239 | { | |
240 | schedule_work(&moom_work); | |
241 | } | |
242 | static struct sysrq_key_op sysrq_moom_op = { | |
243 | .handler = sysrq_handle_moom, | |
244 | .help_msg = "Full", | |
245 | .action_msg = "Manual OOM execution", | |
246 | }; | |
247 | ||
248 | static void sysrq_handle_kill(int key, struct pt_regs *pt_regs, | |
bf36b901 | 249 | struct tty_struct *tty) |
1da177e4 LT |
250 | { |
251 | send_sig_all(SIGKILL); | |
252 | console_loglevel = 8; | |
253 | } | |
254 | static struct sysrq_key_op sysrq_kill_op = { | |
255 | .handler = sysrq_handle_kill, | |
256 | .help_msg = "kIll", | |
257 | .action_msg = "Kill All Tasks", | |
258 | .enable_mask = SYSRQ_ENABLE_SIGNAL, | |
259 | }; | |
260 | ||
1da177e4 LT |
261 | static void sysrq_handle_unrt(int key, struct pt_regs *pt_regs, |
262 | struct tty_struct *tty) | |
263 | { | |
264 | normalize_rt_tasks(); | |
265 | } | |
266 | static struct sysrq_key_op sysrq_unrt_op = { | |
267 | .handler = sysrq_handle_unrt, | |
268 | .help_msg = "Nice", | |
269 | .action_msg = "Nice All RT Tasks", | |
270 | .enable_mask = SYSRQ_ENABLE_RTNICE, | |
271 | }; | |
272 | ||
273 | /* Key Operations table and lock */ | |
274 | static DEFINE_SPINLOCK(sysrq_key_table_lock); | |
bf36b901 AM |
275 | |
276 | static struct sysrq_key_op *sysrq_key_table[36] = { | |
277 | &sysrq_loglevel_op, /* 0 */ | |
278 | &sysrq_loglevel_op, /* 1 */ | |
279 | &sysrq_loglevel_op, /* 2 */ | |
280 | &sysrq_loglevel_op, /* 3 */ | |
281 | &sysrq_loglevel_op, /* 4 */ | |
282 | &sysrq_loglevel_op, /* 5 */ | |
283 | &sysrq_loglevel_op, /* 6 */ | |
284 | &sysrq_loglevel_op, /* 7 */ | |
285 | &sysrq_loglevel_op, /* 8 */ | |
286 | &sysrq_loglevel_op, /* 9 */ | |
287 | ||
288 | /* | |
289 | * Don't use for system provided sysrqs, it is handled specially on | |
290 | * sparc and will never arrive | |
291 | */ | |
292 | NULL, /* a */ | |
293 | &sysrq_reboot_op, /* b */ | |
294 | &sysrq_crashdump_op, /* c */ | |
295 | &sysrq_showlocks_op, /* d */ | |
296 | &sysrq_term_op, /* e */ | |
297 | &sysrq_moom_op, /* f */ | |
298 | NULL, /* g */ | |
299 | NULL, /* h */ | |
300 | &sysrq_kill_op, /* i */ | |
301 | NULL, /* j */ | |
302 | &sysrq_SAK_op, /* k */ | |
303 | NULL, /* l */ | |
304 | &sysrq_showmem_op, /* m */ | |
305 | &sysrq_unrt_op, /* n */ | |
306 | /* This will often be registered as 'Off' at init time */ | |
307 | NULL, /* o */ | |
308 | &sysrq_showregs_op, /* p */ | |
309 | NULL, /* q */ | |
310 | &sysrq_unraw_op, /* r */ | |
311 | &sysrq_sync_op, /* s */ | |
312 | &sysrq_showstate_op, /* t */ | |
313 | &sysrq_mountro_op, /* u */ | |
314 | /* May be assigned at init time by SMP VOYAGER */ | |
315 | NULL, /* v */ | |
316 | NULL, /* w */ | |
317 | NULL, /* x */ | |
318 | NULL, /* y */ | |
319 | NULL /* z */ | |
1da177e4 LT |
320 | }; |
321 | ||
322 | /* key2index calculation, -1 on invalid index */ | |
bf36b901 AM |
323 | static int sysrq_key_table_key2index(int key) |
324 | { | |
1da177e4 | 325 | int retval; |
bf36b901 AM |
326 | |
327 | if ((key >= '0') && (key <= '9')) | |
1da177e4 | 328 | retval = key - '0'; |
bf36b901 | 329 | else if ((key >= 'a') && (key <= 'z')) |
1da177e4 | 330 | retval = key + 10 - 'a'; |
bf36b901 | 331 | else |
1da177e4 | 332 | retval = -1; |
1da177e4 LT |
333 | return retval; |
334 | } | |
335 | ||
336 | /* | |
337 | * get and put functions for the table, exposed to modules. | |
338 | */ | |
bf36b901 AM |
339 | struct sysrq_key_op *__sysrq_get_key_op(int key) |
340 | { | |
341 | struct sysrq_key_op *op_p = NULL; | |
1da177e4 | 342 | int i; |
bf36b901 | 343 | |
1da177e4 | 344 | i = sysrq_key_table_key2index(key); |
bf36b901 AM |
345 | if (i != -1) |
346 | op_p = sysrq_key_table[i]; | |
1da177e4 LT |
347 | return op_p; |
348 | } | |
349 | ||
bf36b901 AM |
350 | static void __sysrq_put_key_op(int key, struct sysrq_key_op *op_p) |
351 | { | |
352 | int i = sysrq_key_table_key2index(key); | |
1da177e4 | 353 | |
1da177e4 LT |
354 | if (i != -1) |
355 | sysrq_key_table[i] = op_p; | |
356 | } | |
357 | ||
358 | /* | |
bf36b901 AM |
359 | * This is the non-locking version of handle_sysrq. It must/can only be called |
360 | * by sysrq key handlers, as they are inside of the lock | |
1da177e4 | 361 | */ |
bf36b901 AM |
362 | void __handle_sysrq(int key, struct pt_regs *pt_regs, struct tty_struct *tty, |
363 | int check_mask) | |
1da177e4 LT |
364 | { |
365 | struct sysrq_key_op *op_p; | |
366 | int orig_log_level; | |
bf36b901 | 367 | int i; |
1da177e4 LT |
368 | unsigned long flags; |
369 | ||
370 | spin_lock_irqsave(&sysrq_key_table_lock, flags); | |
371 | orig_log_level = console_loglevel; | |
372 | console_loglevel = 7; | |
373 | printk(KERN_INFO "SysRq : "); | |
374 | ||
375 | op_p = __sysrq_get_key_op(key); | |
376 | if (op_p) { | |
bf36b901 AM |
377 | /* |
378 | * Should we check for enabled operations (/proc/sysrq-trigger | |
379 | * should not) and is the invoked operation enabled? | |
380 | */ | |
1da177e4 LT |
381 | if (!check_mask || sysrq_enabled == 1 || |
382 | (sysrq_enabled & op_p->enable_mask)) { | |
bf36b901 | 383 | printk("%s\n", op_p->action_msg); |
1da177e4 LT |
384 | console_loglevel = orig_log_level; |
385 | op_p->handler(key, pt_regs, tty); | |
bf36b901 | 386 | } else { |
1da177e4 | 387 | printk("This sysrq operation is disabled.\n"); |
bf36b901 | 388 | } |
1da177e4 LT |
389 | } else { |
390 | printk("HELP : "); | |
391 | /* Only print the help msg once per handler */ | |
bf36b901 AM |
392 | for (i = 0; i < ARRAY_SIZE(sysrq_key_table); i++) { |
393 | if (sysrq_key_table[i]) { | |
394 | int j; | |
395 | ||
396 | for (j = 0; sysrq_key_table[i] != | |
397 | sysrq_key_table[j]; j++) | |
398 | ; | |
399 | if (j != i) | |
400 | continue; | |
401 | printk("%s ", sysrq_key_table[i]->help_msg); | |
402 | } | |
1da177e4 | 403 | } |
bf36b901 | 404 | printk("\n"); |
1da177e4 LT |
405 | console_loglevel = orig_log_level; |
406 | } | |
407 | spin_unlock_irqrestore(&sysrq_key_table_lock, flags); | |
408 | } | |
409 | ||
410 | /* | |
411 | * This function is called by the keyboard handler when SysRq is pressed | |
412 | * and any other keycode arrives. | |
413 | */ | |
1da177e4 LT |
414 | void handle_sysrq(int key, struct pt_regs *pt_regs, struct tty_struct *tty) |
415 | { | |
416 | if (!sysrq_enabled) | |
417 | return; | |
418 | __handle_sysrq(key, pt_regs, tty, 1); | |
419 | } | |
bf36b901 | 420 | EXPORT_SYMBOL(handle_sysrq); |
1da177e4 | 421 | |
cf62ddce | 422 | static int __sysrq_swap_key_ops(int key, struct sysrq_key_op *insert_op_p, |
bf36b901 AM |
423 | struct sysrq_key_op *remove_op_p) |
424 | { | |
1da177e4 LT |
425 | |
426 | int retval; | |
427 | unsigned long flags; | |
428 | ||
429 | spin_lock_irqsave(&sysrq_key_table_lock, flags); | |
430 | if (__sysrq_get_key_op(key) == remove_op_p) { | |
431 | __sysrq_put_key_op(key, insert_op_p); | |
432 | retval = 0; | |
433 | } else { | |
434 | retval = -1; | |
435 | } | |
436 | spin_unlock_irqrestore(&sysrq_key_table_lock, flags); | |
1da177e4 LT |
437 | return retval; |
438 | } | |
439 | ||
440 | int register_sysrq_key(int key, struct sysrq_key_op *op_p) | |
441 | { | |
442 | return __sysrq_swap_key_ops(key, op_p, NULL); | |
443 | } | |
bf36b901 | 444 | EXPORT_SYMBOL(register_sysrq_key); |
1da177e4 LT |
445 | |
446 | int unregister_sysrq_key(int key, struct sysrq_key_op *op_p) | |
447 | { | |
448 | return __sysrq_swap_key_ops(key, NULL, op_p); | |
449 | } | |
1da177e4 | 450 | EXPORT_SYMBOL(unregister_sysrq_key); |