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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 | ||
15 | #include <linux/config.h> | |
16 | #include <linux/sched.h> | |
17 | #include <linux/interrupt.h> | |
18 | #include <linux/mm.h> | |
19 | #include <linux/fs.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> | |
86b1ae38 | 38 | #include <linux/kexec.h> |
1da177e4 LT |
39 | |
40 | #include <asm/ptrace.h> | |
41 | ||
42 | /* Whether we react on sysrq keys or just ignore them */ | |
43 | int sysrq_enabled = 1; | |
44 | ||
45 | /* Loglevel sysrq handler */ | |
46 | static void sysrq_handle_loglevel(int key, struct pt_regs *pt_regs, | |
47 | struct tty_struct *tty) | |
48 | { | |
49 | int i; | |
50 | i = key - '0'; | |
51 | console_loglevel = 7; | |
52 | printk("Loglevel set to %d\n", i); | |
53 | console_loglevel = i; | |
54 | } | |
55 | static struct sysrq_key_op sysrq_loglevel_op = { | |
56 | .handler = sysrq_handle_loglevel, | |
57 | .help_msg = "loglevel0-8", | |
58 | .action_msg = "Changing Loglevel", | |
59 | .enable_mask = SYSRQ_ENABLE_LOG, | |
60 | }; | |
61 | ||
62 | ||
63 | /* SAK sysrq handler */ | |
64 | #ifdef CONFIG_VT | |
65 | static void sysrq_handle_SAK(int key, struct pt_regs *pt_regs, | |
66 | struct tty_struct *tty) | |
67 | { | |
68 | if (tty) | |
69 | do_SAK(tty); | |
70 | reset_vc(vc_cons[fg_console].d); | |
71 | } | |
72 | static struct sysrq_key_op sysrq_SAK_op = { | |
73 | .handler = sysrq_handle_SAK, | |
74 | .help_msg = "saK", | |
75 | .action_msg = "SAK", | |
76 | .enable_mask = SYSRQ_ENABLE_KEYBOARD, | |
77 | }; | |
78 | #endif | |
79 | ||
80 | #ifdef CONFIG_VT | |
81 | /* unraw sysrq handler */ | |
82 | static void sysrq_handle_unraw(int key, struct pt_regs *pt_regs, | |
83 | struct tty_struct *tty) | |
84 | { | |
85 | struct kbd_struct *kbd = &kbd_table[fg_console]; | |
86 | ||
87 | if (kbd) | |
88 | kbd->kbdmode = VC_XLATE; | |
89 | } | |
90 | static struct sysrq_key_op sysrq_unraw_op = { | |
91 | .handler = sysrq_handle_unraw, | |
92 | .help_msg = "unRaw", | |
93 | .action_msg = "Keyboard mode set to XLATE", | |
94 | .enable_mask = SYSRQ_ENABLE_KEYBOARD, | |
95 | }; | |
96 | #endif /* CONFIG_VT */ | |
97 | ||
86b1ae38 HN |
98 | #ifdef CONFIG_KEXEC |
99 | /* crashdump sysrq handler */ | |
100 | static void sysrq_handle_crashdump(int key, struct pt_regs *pt_regs, | |
101 | struct tty_struct *tty) | |
102 | { | |
6e274d14 | 103 | crash_kexec(pt_regs); |
86b1ae38 HN |
104 | } |
105 | static struct sysrq_key_op sysrq_crashdump_op = { | |
106 | .handler = sysrq_handle_crashdump, | |
107 | .help_msg = "Crashdump", | |
108 | .action_msg = "Trigger a crashdump", | |
109 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
110 | }; | |
111 | #endif | |
112 | ||
1da177e4 LT |
113 | /* reboot sysrq handler */ |
114 | static void sysrq_handle_reboot(int key, struct pt_regs *pt_regs, | |
115 | struct tty_struct *tty) | |
116 | { | |
117 | local_irq_enable(); | |
4de8b9b7 | 118 | emergency_restart(); |
1da177e4 LT |
119 | } |
120 | ||
121 | static struct sysrq_key_op sysrq_reboot_op = { | |
122 | .handler = sysrq_handle_reboot, | |
123 | .help_msg = "reBoot", | |
124 | .action_msg = "Resetting", | |
125 | .enable_mask = SYSRQ_ENABLE_BOOT, | |
126 | }; | |
127 | ||
128 | static void sysrq_handle_sync(int key, struct pt_regs *pt_regs, | |
129 | struct tty_struct *tty) | |
130 | { | |
131 | emergency_sync(); | |
132 | } | |
133 | ||
134 | static struct sysrq_key_op sysrq_sync_op = { | |
135 | .handler = sysrq_handle_sync, | |
136 | .help_msg = "Sync", | |
137 | .action_msg = "Emergency Sync", | |
138 | .enable_mask = SYSRQ_ENABLE_SYNC, | |
139 | }; | |
140 | ||
141 | static void sysrq_handle_mountro(int key, struct pt_regs *pt_regs, | |
142 | struct tty_struct *tty) | |
143 | { | |
144 | emergency_remount(); | |
145 | } | |
146 | ||
147 | static struct sysrq_key_op sysrq_mountro_op = { | |
148 | .handler = sysrq_handle_mountro, | |
149 | .help_msg = "Unmount", | |
150 | .action_msg = "Emergency Remount R/O", | |
151 | .enable_mask = SYSRQ_ENABLE_REMOUNT, | |
152 | }; | |
153 | ||
154 | /* END SYNC SYSRQ HANDLERS BLOCK */ | |
155 | ||
156 | ||
157 | /* SHOW SYSRQ HANDLERS BLOCK */ | |
158 | ||
159 | static void sysrq_handle_showregs(int key, struct pt_regs *pt_regs, | |
160 | struct tty_struct *tty) | |
161 | { | |
162 | if (pt_regs) | |
163 | show_regs(pt_regs); | |
164 | } | |
165 | static struct sysrq_key_op sysrq_showregs_op = { | |
166 | .handler = sysrq_handle_showregs, | |
167 | .help_msg = "showPc", | |
168 | .action_msg = "Show Regs", | |
169 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
170 | }; | |
171 | ||
172 | ||
173 | static void sysrq_handle_showstate(int key, struct pt_regs *pt_regs, | |
174 | struct tty_struct *tty) | |
175 | { | |
176 | show_state(); | |
177 | } | |
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, | |
183 | }; | |
184 | ||
185 | ||
186 | static void sysrq_handle_showmem(int key, struct pt_regs *pt_regs, | |
187 | struct tty_struct *tty) | |
188 | { | |
189 | show_mem(); | |
190 | } | |
191 | static struct sysrq_key_op sysrq_showmem_op = { | |
192 | .handler = sysrq_handle_showmem, | |
193 | .help_msg = "showMem", | |
194 | .action_msg = "Show Memory", | |
195 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
196 | }; | |
197 | ||
198 | /* SHOW SYSRQ HANDLERS BLOCK */ | |
199 | ||
200 | ||
201 | /* SIGNAL SYSRQ HANDLERS BLOCK */ | |
202 | ||
203 | /* signal sysrq helper function | |
204 | * Sends a signal to all user processes */ | |
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, | |
217 | struct tty_struct *tty) | |
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 | { | |
79b9ce31 | 231 | out_of_memory(GFP_KERNEL, 0); |
1da177e4 LT |
232 | } |
233 | ||
234 | static DECLARE_WORK(moom_work, moom_callback, NULL); | |
235 | ||
236 | static void sysrq_handle_moom(int key, struct pt_regs *pt_regs, | |
237 | struct tty_struct *tty) | |
238 | { | |
239 | schedule_work(&moom_work); | |
240 | } | |
241 | static struct sysrq_key_op sysrq_moom_op = { | |
242 | .handler = sysrq_handle_moom, | |
243 | .help_msg = "Full", | |
244 | .action_msg = "Manual OOM execution", | |
245 | }; | |
246 | ||
247 | static void sysrq_handle_kill(int key, struct pt_regs *pt_regs, | |
248 | struct tty_struct *tty) | |
249 | { | |
250 | send_sig_all(SIGKILL); | |
251 | console_loglevel = 8; | |
252 | } | |
253 | static struct sysrq_key_op sysrq_kill_op = { | |
254 | .handler = sysrq_handle_kill, | |
255 | .help_msg = "kIll", | |
256 | .action_msg = "Kill All Tasks", | |
257 | .enable_mask = SYSRQ_ENABLE_SIGNAL, | |
258 | }; | |
259 | ||
260 | /* END SIGNAL SYSRQ HANDLERS BLOCK */ | |
261 | ||
262 | static void sysrq_handle_unrt(int key, struct pt_regs *pt_regs, | |
263 | struct tty_struct *tty) | |
264 | { | |
265 | normalize_rt_tasks(); | |
266 | } | |
267 | static struct sysrq_key_op sysrq_unrt_op = { | |
268 | .handler = sysrq_handle_unrt, | |
269 | .help_msg = "Nice", | |
270 | .action_msg = "Nice All RT Tasks", | |
271 | .enable_mask = SYSRQ_ENABLE_RTNICE, | |
272 | }; | |
273 | ||
274 | /* Key Operations table and lock */ | |
275 | static DEFINE_SPINLOCK(sysrq_key_table_lock); | |
276 | #define SYSRQ_KEY_TABLE_LENGTH 36 | |
277 | static struct sysrq_key_op *sysrq_key_table[SYSRQ_KEY_TABLE_LENGTH] = { | |
278 | /* 0 */ &sysrq_loglevel_op, | |
279 | /* 1 */ &sysrq_loglevel_op, | |
280 | /* 2 */ &sysrq_loglevel_op, | |
281 | /* 3 */ &sysrq_loglevel_op, | |
282 | /* 4 */ &sysrq_loglevel_op, | |
283 | /* 5 */ &sysrq_loglevel_op, | |
284 | /* 6 */ &sysrq_loglevel_op, | |
285 | /* 7 */ &sysrq_loglevel_op, | |
286 | /* 8 */ &sysrq_loglevel_op, | |
287 | /* 9 */ &sysrq_loglevel_op, | |
288 | /* a */ NULL, /* Don't use for system provided sysrqs, | |
289 | it is handled specially on the sparc | |
290 | and will never arrive */ | |
291 | /* b */ &sysrq_reboot_op, | |
86b1ae38 HN |
292 | #ifdef CONFIG_KEXEC |
293 | /* c */ &sysrq_crashdump_op, | |
294 | #else | |
295 | /* c */ NULL, | |
296 | #endif | |
297 | /* d */ NULL, | |
1da177e4 LT |
298 | /* e */ &sysrq_term_op, |
299 | /* f */ &sysrq_moom_op, | |
300 | /* g */ NULL, | |
301 | /* h */ NULL, | |
302 | /* i */ &sysrq_kill_op, | |
303 | /* j */ NULL, | |
304 | #ifdef CONFIG_VT | |
305 | /* k */ &sysrq_SAK_op, | |
306 | #else | |
307 | /* k */ NULL, | |
308 | #endif | |
309 | /* l */ NULL, | |
310 | /* m */ &sysrq_showmem_op, | |
311 | /* n */ &sysrq_unrt_op, | |
312 | /* o */ NULL, /* This will often be registered | |
313 | as 'Off' at init time */ | |
314 | /* p */ &sysrq_showregs_op, | |
315 | /* q */ NULL, | |
316 | #ifdef CONFIG_VT | |
317 | /* r */ &sysrq_unraw_op, | |
318 | #else | |
319 | /* r */ NULL, | |
320 | #endif | |
321 | /* s */ &sysrq_sync_op, | |
322 | /* t */ &sysrq_showstate_op, | |
323 | /* u */ &sysrq_mountro_op, | |
324 | /* v */ NULL, /* May be assigned at init time by SMP VOYAGER */ | |
325 | /* w */ NULL, | |
326 | /* x */ NULL, | |
327 | /* y */ NULL, | |
328 | /* z */ NULL | |
329 | }; | |
330 | ||
331 | /* key2index calculation, -1 on invalid index */ | |
332 | static int sysrq_key_table_key2index(int key) { | |
333 | int retval; | |
334 | if ((key >= '0') && (key <= '9')) { | |
335 | retval = key - '0'; | |
336 | } else if ((key >= 'a') && (key <= 'z')) { | |
337 | retval = key + 10 - 'a'; | |
338 | } else { | |
339 | retval = -1; | |
340 | } | |
341 | return retval; | |
342 | } | |
343 | ||
344 | /* | |
345 | * get and put functions for the table, exposed to modules. | |
346 | */ | |
347 | ||
348 | struct sysrq_key_op *__sysrq_get_key_op (int key) { | |
349 | struct sysrq_key_op *op_p; | |
350 | int i; | |
351 | ||
352 | i = sysrq_key_table_key2index(key); | |
353 | op_p = (i == -1) ? NULL : sysrq_key_table[i]; | |
354 | return op_p; | |
355 | } | |
356 | ||
cf62ddce | 357 | static void __sysrq_put_key_op (int key, struct sysrq_key_op *op_p) { |
1da177e4 LT |
358 | int i; |
359 | ||
360 | i = sysrq_key_table_key2index(key); | |
361 | if (i != -1) | |
362 | sysrq_key_table[i] = op_p; | |
363 | } | |
364 | ||
365 | /* | |
366 | * This is the non-locking version of handle_sysrq | |
367 | * It must/can only be called by sysrq key handlers, | |
368 | * as they are inside of the lock | |
369 | */ | |
370 | ||
371 | void __handle_sysrq(int key, struct pt_regs *pt_regs, struct tty_struct *tty, int check_mask) | |
372 | { | |
373 | struct sysrq_key_op *op_p; | |
374 | int orig_log_level; | |
375 | int i, j; | |
376 | unsigned long flags; | |
377 | ||
378 | spin_lock_irqsave(&sysrq_key_table_lock, flags); | |
379 | orig_log_level = console_loglevel; | |
380 | console_loglevel = 7; | |
381 | printk(KERN_INFO "SysRq : "); | |
382 | ||
383 | op_p = __sysrq_get_key_op(key); | |
384 | if (op_p) { | |
385 | /* Should we check for enabled operations (/proc/sysrq-trigger should not) | |
386 | * and is the invoked operation enabled? */ | |
387 | if (!check_mask || sysrq_enabled == 1 || | |
388 | (sysrq_enabled & op_p->enable_mask)) { | |
389 | printk ("%s\n", op_p->action_msg); | |
390 | console_loglevel = orig_log_level; | |
391 | op_p->handler(key, pt_regs, tty); | |
392 | } | |
393 | else | |
394 | printk("This sysrq operation is disabled.\n"); | |
395 | } else { | |
396 | printk("HELP : "); | |
397 | /* Only print the help msg once per handler */ | |
398 | for (i=0; i<SYSRQ_KEY_TABLE_LENGTH; i++) | |
399 | if (sysrq_key_table[i]) { | |
400 | for (j=0; sysrq_key_table[i] != sysrq_key_table[j]; j++); | |
401 | if (j == i) | |
402 | printk ("%s ", sysrq_key_table[i]->help_msg); | |
403 | } | |
404 | printk ("\n"); | |
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 | */ | |
414 | ||
415 | void handle_sysrq(int key, struct pt_regs *pt_regs, struct tty_struct *tty) | |
416 | { | |
417 | if (!sysrq_enabled) | |
418 | return; | |
419 | __handle_sysrq(key, pt_regs, tty, 1); | |
420 | } | |
421 | ||
cf62ddce | 422 | static int __sysrq_swap_key_ops(int key, struct sysrq_key_op *insert_op_p, |
1da177e4 LT |
423 | struct sysrq_key_op *remove_op_p) { |
424 | ||
425 | int retval; | |
426 | unsigned long flags; | |
427 | ||
428 | spin_lock_irqsave(&sysrq_key_table_lock, flags); | |
429 | if (__sysrq_get_key_op(key) == remove_op_p) { | |
430 | __sysrq_put_key_op(key, insert_op_p); | |
431 | retval = 0; | |
432 | } else { | |
433 | retval = -1; | |
434 | } | |
435 | spin_unlock_irqrestore(&sysrq_key_table_lock, flags); | |
436 | ||
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 | } | |
444 | ||
445 | int unregister_sysrq_key(int key, struct sysrq_key_op *op_p) | |
446 | { | |
447 | return __sysrq_swap_key_ops(key, NULL, op_p); | |
448 | } | |
449 | ||
450 | EXPORT_SYMBOL(handle_sysrq); | |
451 | EXPORT_SYMBOL(register_sysrq_key); | |
452 | EXPORT_SYMBOL(unregister_sysrq_key); |