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Commit | Line | Data |
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97f5f0cd | 1 | /* |
1da177e4 LT |
2 | * Linux Magic System Request Key Hacks |
3 | * | |
4 | * (c) 1997 Martin Mares <mj@atrey.karlin.mff.cuni.cz> | |
5 | * based on ideas by Pavel Machek <pavel@atrey.karlin.mff.cuni.cz> | |
6 | * | |
7 | * (c) 2000 Crutcher Dunnavant <crutcher+kernel@datastacks.com> | |
8 | * overhauled to use key registration | |
9 | * based upon discusions in irc://irc.openprojects.net/#kernelnewbies | |
97f5f0cd DT |
10 | * |
11 | * Copyright (c) 2010 Dmitry Torokhov | |
12 | * Input handler conversion | |
1da177e4 LT |
13 | */ |
14 | ||
97f5f0cd DT |
15 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
16 | ||
1da177e4 LT |
17 | #include <linux/sched.h> |
18 | #include <linux/interrupt.h> | |
19 | #include <linux/mm.h> | |
20 | #include <linux/fs.h> | |
21 | #include <linux/tty.h> | |
22 | #include <linux/mount.h> | |
23 | #include <linux/kdev_t.h> | |
24 | #include <linux/major.h> | |
25 | #include <linux/reboot.h> | |
26 | #include <linux/sysrq.h> | |
27 | #include <linux/kbd_kern.h> | |
f40cbaa5 | 28 | #include <linux/proc_fs.h> |
c1dc0b9c | 29 | #include <linux/nmi.h> |
1da177e4 | 30 | #include <linux/quotaops.h> |
cdd6c482 | 31 | #include <linux/perf_event.h> |
1da177e4 LT |
32 | #include <linux/kernel.h> |
33 | #include <linux/module.h> | |
34 | #include <linux/suspend.h> | |
35 | #include <linux/writeback.h> | |
36 | #include <linux/buffer_head.h> /* for fsync_bdev() */ | |
37 | #include <linux/swap.h> | |
38 | #include <linux/spinlock.h> | |
39 | #include <linux/vt_kern.h> | |
40 | #include <linux/workqueue.h> | |
88ad0bf6 | 41 | #include <linux/hrtimer.h> |
5a3135c2 | 42 | #include <linux/oom.h> |
5a0e3ad6 | 43 | #include <linux/slab.h> |
97f5f0cd | 44 | #include <linux/input.h> |
1da177e4 LT |
45 | |
46 | #include <asm/ptrace.h> | |
2033b0c3 | 47 | #include <asm/irq_regs.h> |
1da177e4 LT |
48 | |
49 | /* Whether we react on sysrq keys or just ignore them */ | |
97f5f0cd DT |
50 | static int __read_mostly sysrq_enabled = 1; |
51 | static bool __read_mostly sysrq_always_enabled; | |
5d6f647f | 52 | |
97f5f0cd | 53 | static bool sysrq_on(void) |
5d6f647f | 54 | { |
97f5f0cd | 55 | return sysrq_enabled || sysrq_always_enabled; |
5d6f647f IM |
56 | } |
57 | ||
58 | /* | |
59 | * A value of 1 means 'all', other nonzero values are an op mask: | |
60 | */ | |
97f5f0cd | 61 | static bool sysrq_on_mask(int mask) |
5d6f647f | 62 | { |
97f5f0cd DT |
63 | return sysrq_always_enabled || |
64 | sysrq_enabled == 1 || | |
65 | (sysrq_enabled & mask); | |
5d6f647f IM |
66 | } |
67 | ||
68 | static int __init sysrq_always_enabled_setup(char *str) | |
69 | { | |
97f5f0cd DT |
70 | sysrq_always_enabled = true; |
71 | pr_info("sysrq always enabled.\n"); | |
5d6f647f IM |
72 | |
73 | return 1; | |
74 | } | |
75 | ||
76 | __setup("sysrq_always_enabled", sysrq_always_enabled_setup); | |
77 | ||
1da177e4 | 78 | |
7d12e780 | 79 | static void sysrq_handle_loglevel(int key, struct tty_struct *tty) |
1da177e4 LT |
80 | { |
81 | int i; | |
97f5f0cd | 82 | |
1da177e4 LT |
83 | i = key - '0'; |
84 | console_loglevel = 7; | |
85 | printk("Loglevel set to %d\n", i); | |
86 | console_loglevel = i; | |
bf36b901 | 87 | } |
1da177e4 LT |
88 | static struct sysrq_key_op sysrq_loglevel_op = { |
89 | .handler = sysrq_handle_loglevel, | |
208b95ce | 90 | .help_msg = "loglevel(0-9)", |
1da177e4 LT |
91 | .action_msg = "Changing Loglevel", |
92 | .enable_mask = SYSRQ_ENABLE_LOG, | |
93 | }; | |
94 | ||
1da177e4 | 95 | #ifdef CONFIG_VT |
7d12e780 | 96 | static void sysrq_handle_SAK(int key, struct tty_struct *tty) |
1da177e4 | 97 | { |
8b6312f4 | 98 | struct work_struct *SAK_work = &vc_cons[fg_console].SAK_work; |
8b6312f4 | 99 | schedule_work(SAK_work); |
1da177e4 LT |
100 | } |
101 | static struct sysrq_key_op sysrq_SAK_op = { | |
102 | .handler = sysrq_handle_SAK, | |
103 | .help_msg = "saK", | |
104 | .action_msg = "SAK", | |
105 | .enable_mask = SYSRQ_ENABLE_KEYBOARD, | |
106 | }; | |
bf36b901 | 107 | #else |
97f5f0cd | 108 | #define sysrq_SAK_op (*(struct sysrq_key_op *)NULL) |
1da177e4 LT |
109 | #endif |
110 | ||
111 | #ifdef CONFIG_VT | |
7d12e780 | 112 | static void sysrq_handle_unraw(int key, struct tty_struct *tty) |
1da177e4 LT |
113 | { |
114 | struct kbd_struct *kbd = &kbd_table[fg_console]; | |
115 | ||
116 | if (kbd) | |
2e8ecb9d | 117 | kbd->kbdmode = default_utf8 ? VC_UNICODE : VC_XLATE; |
1da177e4 LT |
118 | } |
119 | static struct sysrq_key_op sysrq_unraw_op = { | |
120 | .handler = sysrq_handle_unraw, | |
121 | .help_msg = "unRaw", | |
2e8ecb9d | 122 | .action_msg = "Keyboard mode set to system default", |
1da177e4 LT |
123 | .enable_mask = SYSRQ_ENABLE_KEYBOARD, |
124 | }; | |
bf36b901 | 125 | #else |
97f5f0cd | 126 | #define sysrq_unraw_op (*(struct sysrq_key_op *)NULL) |
1da177e4 LT |
127 | #endif /* CONFIG_VT */ |
128 | ||
d6580a9f | 129 | static void sysrq_handle_crash(int key, struct tty_struct *tty) |
86b1ae38 | 130 | { |
d6580a9f | 131 | char *killer = NULL; |
cab8bd34 HS |
132 | |
133 | panic_on_oops = 1; /* force panic */ | |
134 | wmb(); | |
d6580a9f | 135 | *killer = 1; |
86b1ae38 | 136 | } |
cab8bd34 | 137 | static struct sysrq_key_op sysrq_crash_op = { |
d6580a9f NH |
138 | .handler = sysrq_handle_crash, |
139 | .help_msg = "Crash", | |
140 | .action_msg = "Trigger a crash", | |
86b1ae38 HN |
141 | .enable_mask = SYSRQ_ENABLE_DUMP, |
142 | }; | |
86b1ae38 | 143 | |
7d12e780 | 144 | static void sysrq_handle_reboot(int key, struct tty_struct *tty) |
1da177e4 | 145 | { |
b2e9c7d0 | 146 | lockdep_off(); |
1da177e4 | 147 | local_irq_enable(); |
4de8b9b7 | 148 | emergency_restart(); |
1da177e4 | 149 | } |
1da177e4 LT |
150 | static struct sysrq_key_op sysrq_reboot_op = { |
151 | .handler = sysrq_handle_reboot, | |
152 | .help_msg = "reBoot", | |
153 | .action_msg = "Resetting", | |
154 | .enable_mask = SYSRQ_ENABLE_BOOT, | |
155 | }; | |
156 | ||
7d12e780 | 157 | static void sysrq_handle_sync(int key, struct tty_struct *tty) |
1da177e4 LT |
158 | { |
159 | emergency_sync(); | |
160 | } | |
1da177e4 LT |
161 | static struct sysrq_key_op sysrq_sync_op = { |
162 | .handler = sysrq_handle_sync, | |
163 | .help_msg = "Sync", | |
164 | .action_msg = "Emergency Sync", | |
165 | .enable_mask = SYSRQ_ENABLE_SYNC, | |
166 | }; | |
167 | ||
88ad0bf6 IM |
168 | static void sysrq_handle_show_timers(int key, struct tty_struct *tty) |
169 | { | |
170 | sysrq_timer_list_show(); | |
171 | } | |
172 | ||
173 | static struct sysrq_key_op sysrq_show_timers_op = { | |
174 | .handler = sysrq_handle_show_timers, | |
175 | .help_msg = "show-all-timers(Q)", | |
322acf65 | 176 | .action_msg = "Show clockevent devices & pending hrtimers (no others)", |
88ad0bf6 IM |
177 | }; |
178 | ||
7d12e780 | 179 | static void sysrq_handle_mountro(int key, struct tty_struct *tty) |
1da177e4 LT |
180 | { |
181 | emergency_remount(); | |
182 | } | |
1da177e4 LT |
183 | static struct sysrq_key_op sysrq_mountro_op = { |
184 | .handler = sysrq_handle_mountro, | |
185 | .help_msg = "Unmount", | |
186 | .action_msg = "Emergency Remount R/O", | |
187 | .enable_mask = SYSRQ_ENABLE_REMOUNT, | |
188 | }; | |
189 | ||
8c64580d | 190 | #ifdef CONFIG_LOCKDEP |
7d12e780 | 191 | static void sysrq_handle_showlocks(int key, struct tty_struct *tty) |
de5097c2 | 192 | { |
9a11b49a | 193 | debug_show_all_locks(); |
de5097c2 | 194 | } |
8c64580d | 195 | |
de5097c2 IM |
196 | static struct sysrq_key_op sysrq_showlocks_op = { |
197 | .handler = sysrq_handle_showlocks, | |
198 | .help_msg = "show-all-locks(D)", | |
199 | .action_msg = "Show Locks Held", | |
200 | }; | |
bf36b901 | 201 | #else |
97f5f0cd | 202 | #define sysrq_showlocks_op (*(struct sysrq_key_op *)NULL) |
de5097c2 | 203 | #endif |
1da177e4 | 204 | |
5045bcae RR |
205 | #ifdef CONFIG_SMP |
206 | static DEFINE_SPINLOCK(show_lock); | |
207 | ||
208 | static void showacpu(void *dummy) | |
209 | { | |
210 | unsigned long flags; | |
211 | ||
212 | /* Idle CPUs have no interesting backtrace. */ | |
213 | if (idle_cpu(smp_processor_id())) | |
214 | return; | |
215 | ||
216 | spin_lock_irqsave(&show_lock, flags); | |
217 | printk(KERN_INFO "CPU%d:\n", smp_processor_id()); | |
218 | show_stack(NULL, NULL); | |
219 | spin_unlock_irqrestore(&show_lock, flags); | |
220 | } | |
221 | ||
222 | static void sysrq_showregs_othercpus(struct work_struct *dummy) | |
223 | { | |
8b604d52 | 224 | smp_call_function(showacpu, NULL, 0); |
5045bcae RR |
225 | } |
226 | ||
227 | static DECLARE_WORK(sysrq_showallcpus, sysrq_showregs_othercpus); | |
228 | ||
229 | static void sysrq_handle_showallcpus(int key, struct tty_struct *tty) | |
230 | { | |
47cab6a7 IM |
231 | /* |
232 | * Fall back to the workqueue based printing if the | |
233 | * backtrace printing did not succeed or the | |
234 | * architecture has no support for it: | |
235 | */ | |
236 | if (!trigger_all_cpu_backtrace()) { | |
237 | struct pt_regs *regs = get_irq_regs(); | |
238 | ||
239 | if (regs) { | |
240 | printk(KERN_INFO "CPU%d:\n", smp_processor_id()); | |
241 | show_regs(regs); | |
242 | } | |
243 | schedule_work(&sysrq_showallcpus); | |
244 | } | |
5045bcae RR |
245 | } |
246 | ||
247 | static struct sysrq_key_op sysrq_showallcpus_op = { | |
248 | .handler = sysrq_handle_showallcpus, | |
208b95ce | 249 | .help_msg = "show-backtrace-all-active-cpus(L)", |
5045bcae RR |
250 | .action_msg = "Show backtrace of all active CPUs", |
251 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
252 | }; | |
253 | #endif | |
254 | ||
7d12e780 | 255 | static void sysrq_handle_showregs(int key, struct tty_struct *tty) |
1da177e4 | 256 | { |
7d12e780 DH |
257 | struct pt_regs *regs = get_irq_regs(); |
258 | if (regs) | |
259 | show_regs(regs); | |
cdd6c482 | 260 | perf_event_print_debug(); |
1da177e4 LT |
261 | } |
262 | static struct sysrq_key_op sysrq_showregs_op = { | |
263 | .handler = sysrq_handle_showregs, | |
208b95ce | 264 | .help_msg = "show-registers(P)", |
1da177e4 LT |
265 | .action_msg = "Show Regs", |
266 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
267 | }; | |
268 | ||
7d12e780 | 269 | static void sysrq_handle_showstate(int key, struct tty_struct *tty) |
1da177e4 LT |
270 | { |
271 | show_state(); | |
272 | } | |
273 | static struct sysrq_key_op sysrq_showstate_op = { | |
274 | .handler = sysrq_handle_showstate, | |
208b95ce | 275 | .help_msg = "show-task-states(T)", |
1da177e4 LT |
276 | .action_msg = "Show State", |
277 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
278 | }; | |
279 | ||
e59e2ae2 IM |
280 | static void sysrq_handle_showstate_blocked(int key, struct tty_struct *tty) |
281 | { | |
282 | show_state_filter(TASK_UNINTERRUPTIBLE); | |
283 | } | |
284 | static struct sysrq_key_op sysrq_showstate_blocked_op = { | |
285 | .handler = sysrq_handle_showstate_blocked, | |
208b95ce | 286 | .help_msg = "show-blocked-tasks(W)", |
e59e2ae2 IM |
287 | .action_msg = "Show Blocked State", |
288 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
289 | }; | |
290 | ||
69f698ad PZ |
291 | #ifdef CONFIG_TRACING |
292 | #include <linux/ftrace.h> | |
293 | ||
294 | static void sysrq_ftrace_dump(int key, struct tty_struct *tty) | |
295 | { | |
cecbca96 | 296 | ftrace_dump(DUMP_ALL); |
69f698ad PZ |
297 | } |
298 | static struct sysrq_key_op sysrq_ftrace_dump_op = { | |
299 | .handler = sysrq_ftrace_dump, | |
3871f2ff | 300 | .help_msg = "dump-ftrace-buffer(Z)", |
69f698ad PZ |
301 | .action_msg = "Dump ftrace buffer", |
302 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
303 | }; | |
304 | #else | |
97f5f0cd | 305 | #define sysrq_ftrace_dump_op (*(struct sysrq_key_op *)NULL) |
69f698ad | 306 | #endif |
e59e2ae2 | 307 | |
7d12e780 | 308 | static void sysrq_handle_showmem(int key, struct tty_struct *tty) |
1da177e4 LT |
309 | { |
310 | show_mem(); | |
311 | } | |
312 | static struct sysrq_key_op sysrq_showmem_op = { | |
313 | .handler = sysrq_handle_showmem, | |
208b95ce | 314 | .help_msg = "show-memory-usage(M)", |
1da177e4 LT |
315 | .action_msg = "Show Memory", |
316 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
317 | }; | |
318 | ||
bf36b901 AM |
319 | /* |
320 | * Signal sysrq helper function. Sends a signal to all user processes. | |
321 | */ | |
1da177e4 LT |
322 | static void send_sig_all(int sig) |
323 | { | |
324 | struct task_struct *p; | |
325 | ||
326 | for_each_process(p) { | |
b460cbc5 | 327 | if (p->mm && !is_global_init(p)) |
1da177e4 LT |
328 | /* Not swapper, init nor kernel thread */ |
329 | force_sig(sig, p); | |
330 | } | |
331 | } | |
332 | ||
7d12e780 | 333 | static void sysrq_handle_term(int key, struct tty_struct *tty) |
1da177e4 LT |
334 | { |
335 | send_sig_all(SIGTERM); | |
336 | console_loglevel = 8; | |
337 | } | |
338 | static struct sysrq_key_op sysrq_term_op = { | |
339 | .handler = sysrq_handle_term, | |
208b95ce | 340 | .help_msg = "terminate-all-tasks(E)", |
1da177e4 LT |
341 | .action_msg = "Terminate All Tasks", |
342 | .enable_mask = SYSRQ_ENABLE_SIGNAL, | |
343 | }; | |
344 | ||
65f27f38 | 345 | static void moom_callback(struct work_struct *ignored) |
1da177e4 | 346 | { |
4365a567 | 347 | out_of_memory(node_zonelist(0, GFP_KERNEL), GFP_KERNEL, 0, NULL); |
1da177e4 LT |
348 | } |
349 | ||
65f27f38 | 350 | static DECLARE_WORK(moom_work, moom_callback); |
1da177e4 | 351 | |
7d12e780 | 352 | static void sysrq_handle_moom(int key, struct tty_struct *tty) |
1da177e4 LT |
353 | { |
354 | schedule_work(&moom_work); | |
355 | } | |
356 | static struct sysrq_key_op sysrq_moom_op = { | |
357 | .handler = sysrq_handle_moom, | |
208b95ce | 358 | .help_msg = "memory-full-oom-kill(F)", |
1da177e4 | 359 | .action_msg = "Manual OOM execution", |
b4236f81 | 360 | .enable_mask = SYSRQ_ENABLE_SIGNAL, |
1da177e4 LT |
361 | }; |
362 | ||
c2d75438 ES |
363 | #ifdef CONFIG_BLOCK |
364 | static void sysrq_handle_thaw(int key, struct tty_struct *tty) | |
365 | { | |
366 | emergency_thaw_all(); | |
367 | } | |
368 | static struct sysrq_key_op sysrq_thaw_op = { | |
369 | .handler = sysrq_handle_thaw, | |
370 | .help_msg = "thaw-filesystems(J)", | |
371 | .action_msg = "Emergency Thaw of all frozen filesystems", | |
372 | .enable_mask = SYSRQ_ENABLE_SIGNAL, | |
373 | }; | |
374 | #endif | |
375 | ||
7d12e780 | 376 | static void sysrq_handle_kill(int key, struct tty_struct *tty) |
1da177e4 LT |
377 | { |
378 | send_sig_all(SIGKILL); | |
379 | console_loglevel = 8; | |
380 | } | |
381 | static struct sysrq_key_op sysrq_kill_op = { | |
382 | .handler = sysrq_handle_kill, | |
208b95ce | 383 | .help_msg = "kill-all-tasks(I)", |
1da177e4 LT |
384 | .action_msg = "Kill All Tasks", |
385 | .enable_mask = SYSRQ_ENABLE_SIGNAL, | |
386 | }; | |
387 | ||
7d12e780 | 388 | static void sysrq_handle_unrt(int key, struct tty_struct *tty) |
1da177e4 LT |
389 | { |
390 | normalize_rt_tasks(); | |
391 | } | |
392 | static struct sysrq_key_op sysrq_unrt_op = { | |
393 | .handler = sysrq_handle_unrt, | |
208b95ce | 394 | .help_msg = "nice-all-RT-tasks(N)", |
1da177e4 LT |
395 | .action_msg = "Nice All RT Tasks", |
396 | .enable_mask = SYSRQ_ENABLE_RTNICE, | |
397 | }; | |
398 | ||
399 | /* Key Operations table and lock */ | |
400 | static DEFINE_SPINLOCK(sysrq_key_table_lock); | |
bf36b901 AM |
401 | |
402 | static struct sysrq_key_op *sysrq_key_table[36] = { | |
403 | &sysrq_loglevel_op, /* 0 */ | |
404 | &sysrq_loglevel_op, /* 1 */ | |
405 | &sysrq_loglevel_op, /* 2 */ | |
406 | &sysrq_loglevel_op, /* 3 */ | |
407 | &sysrq_loglevel_op, /* 4 */ | |
408 | &sysrq_loglevel_op, /* 5 */ | |
409 | &sysrq_loglevel_op, /* 6 */ | |
410 | &sysrq_loglevel_op, /* 7 */ | |
411 | &sysrq_loglevel_op, /* 8 */ | |
412 | &sysrq_loglevel_op, /* 9 */ | |
413 | ||
414 | /* | |
d346cce3 RD |
415 | * a: Don't use for system provided sysrqs, it is handled specially on |
416 | * sparc and will never arrive. | |
bf36b901 AM |
417 | */ |
418 | NULL, /* a */ | |
419 | &sysrq_reboot_op, /* b */ | |
cab8bd34 | 420 | &sysrq_crash_op, /* c & ibm_emac driver debug */ |
bf36b901 AM |
421 | &sysrq_showlocks_op, /* d */ |
422 | &sysrq_term_op, /* e */ | |
423 | &sysrq_moom_op, /* f */ | |
364b5b7b | 424 | /* g: May be registered for the kernel debugger */ |
bf36b901 | 425 | NULL, /* g */ |
c2d75438 | 426 | NULL, /* h - reserved for help */ |
bf36b901 | 427 | &sysrq_kill_op, /* i */ |
c2d75438 ES |
428 | #ifdef CONFIG_BLOCK |
429 | &sysrq_thaw_op, /* j */ | |
430 | #else | |
bf36b901 | 431 | NULL, /* j */ |
c2d75438 | 432 | #endif |
bf36b901 | 433 | &sysrq_SAK_op, /* k */ |
5045bcae RR |
434 | #ifdef CONFIG_SMP |
435 | &sysrq_showallcpus_op, /* l */ | |
436 | #else | |
bf36b901 | 437 | NULL, /* l */ |
5045bcae | 438 | #endif |
bf36b901 AM |
439 | &sysrq_showmem_op, /* m */ |
440 | &sysrq_unrt_op, /* n */ | |
d346cce3 | 441 | /* o: This will often be registered as 'Off' at init time */ |
bf36b901 AM |
442 | NULL, /* o */ |
443 | &sysrq_showregs_op, /* p */ | |
88ad0bf6 | 444 | &sysrq_show_timers_op, /* q */ |
d346cce3 | 445 | &sysrq_unraw_op, /* r */ |
bf36b901 AM |
446 | &sysrq_sync_op, /* s */ |
447 | &sysrq_showstate_op, /* t */ | |
448 | &sysrq_mountro_op, /* u */ | |
364b5b7b | 449 | /* v: May be registered for frame buffer console restore */ |
bf36b901 | 450 | NULL, /* v */ |
d346cce3 RD |
451 | &sysrq_showstate_blocked_op, /* w */ |
452 | /* x: May be registered on ppc/powerpc for xmon */ | |
453 | NULL, /* x */ | |
93dae5b7 | 454 | /* y: May be registered on sparc64 for global register dump */ |
bf36b901 | 455 | NULL, /* y */ |
69f698ad | 456 | &sysrq_ftrace_dump_op, /* z */ |
1da177e4 LT |
457 | }; |
458 | ||
459 | /* key2index calculation, -1 on invalid index */ | |
bf36b901 AM |
460 | static int sysrq_key_table_key2index(int key) |
461 | { | |
1da177e4 | 462 | int retval; |
bf36b901 AM |
463 | |
464 | if ((key >= '0') && (key <= '9')) | |
1da177e4 | 465 | retval = key - '0'; |
bf36b901 | 466 | else if ((key >= 'a') && (key <= 'z')) |
1da177e4 | 467 | retval = key + 10 - 'a'; |
bf36b901 | 468 | else |
1da177e4 | 469 | retval = -1; |
1da177e4 LT |
470 | return retval; |
471 | } | |
472 | ||
473 | /* | |
474 | * get and put functions for the table, exposed to modules. | |
475 | */ | |
bf36b901 AM |
476 | struct sysrq_key_op *__sysrq_get_key_op(int key) |
477 | { | |
478 | struct sysrq_key_op *op_p = NULL; | |
1da177e4 | 479 | int i; |
bf36b901 | 480 | |
1da177e4 | 481 | i = sysrq_key_table_key2index(key); |
bf36b901 AM |
482 | if (i != -1) |
483 | op_p = sysrq_key_table[i]; | |
97f5f0cd | 484 | |
1da177e4 LT |
485 | return op_p; |
486 | } | |
487 | ||
bf36b901 AM |
488 | static void __sysrq_put_key_op(int key, struct sysrq_key_op *op_p) |
489 | { | |
490 | int i = sysrq_key_table_key2index(key); | |
1da177e4 | 491 | |
1da177e4 LT |
492 | if (i != -1) |
493 | sysrq_key_table[i] = op_p; | |
494 | } | |
495 | ||
97f5f0cd | 496 | static void __handle_sysrq(int key, struct tty_struct *tty, int check_mask) |
1da177e4 LT |
497 | { |
498 | struct sysrq_key_op *op_p; | |
499 | int orig_log_level; | |
bf36b901 | 500 | int i; |
1da177e4 LT |
501 | unsigned long flags; |
502 | ||
503 | spin_lock_irqsave(&sysrq_key_table_lock, flags); | |
fb144adc AW |
504 | /* |
505 | * Raise the apparent loglevel to maximum so that the sysrq header | |
506 | * is shown to provide the user with positive feedback. We do not | |
507 | * simply emit this at KERN_EMERG as that would change message | |
508 | * routing in the consumers of /proc/kmsg. | |
509 | */ | |
1da177e4 LT |
510 | orig_log_level = console_loglevel; |
511 | console_loglevel = 7; | |
512 | printk(KERN_INFO "SysRq : "); | |
513 | ||
514 | op_p = __sysrq_get_key_op(key); | |
515 | if (op_p) { | |
bf36b901 AM |
516 | /* |
517 | * Should we check for enabled operations (/proc/sysrq-trigger | |
518 | * should not) and is the invoked operation enabled? | |
519 | */ | |
5d6f647f | 520 | if (!check_mask || sysrq_on_mask(op_p->enable_mask)) { |
bf36b901 | 521 | printk("%s\n", op_p->action_msg); |
1da177e4 | 522 | console_loglevel = orig_log_level; |
7d12e780 | 523 | op_p->handler(key, tty); |
bf36b901 | 524 | } else { |
1da177e4 | 525 | printk("This sysrq operation is disabled.\n"); |
bf36b901 | 526 | } |
1da177e4 LT |
527 | } else { |
528 | printk("HELP : "); | |
529 | /* Only print the help msg once per handler */ | |
bf36b901 AM |
530 | for (i = 0; i < ARRAY_SIZE(sysrq_key_table); i++) { |
531 | if (sysrq_key_table[i]) { | |
532 | int j; | |
533 | ||
534 | for (j = 0; sysrq_key_table[i] != | |
535 | sysrq_key_table[j]; j++) | |
536 | ; | |
537 | if (j != i) | |
538 | continue; | |
539 | printk("%s ", sysrq_key_table[i]->help_msg); | |
540 | } | |
1da177e4 | 541 | } |
bf36b901 | 542 | printk("\n"); |
1da177e4 LT |
543 | console_loglevel = orig_log_level; |
544 | } | |
545 | spin_unlock_irqrestore(&sysrq_key_table_lock, flags); | |
546 | } | |
547 | ||
7d12e780 | 548 | void handle_sysrq(int key, struct tty_struct *tty) |
1da177e4 | 549 | { |
5d6f647f IM |
550 | if (sysrq_on()) |
551 | __handle_sysrq(key, tty, 1); | |
1da177e4 | 552 | } |
bf36b901 | 553 | EXPORT_SYMBOL(handle_sysrq); |
1da177e4 | 554 | |
97f5f0cd DT |
555 | #ifdef CONFIG_INPUT |
556 | ||
557 | /* Simple translation table for the SysRq keys */ | |
558 | static const unsigned char sysrq_xlate[KEY_MAX + 1] = | |
559 | "\000\0331234567890-=\177\t" /* 0x00 - 0x0f */ | |
560 | "qwertyuiop[]\r\000as" /* 0x10 - 0x1f */ | |
561 | "dfghjkl;'`\000\\zxcv" /* 0x20 - 0x2f */ | |
562 | "bnm,./\000*\000 \000\201\202\203\204\205" /* 0x30 - 0x3f */ | |
563 | "\206\207\210\211\212\000\000789-456+1" /* 0x40 - 0x4f */ | |
564 | "230\177\000\000\213\214\000\000\000\000\000\000\000\000\000\000" /* 0x50 - 0x5f */ | |
565 | "\r\000/"; /* 0x60 - 0x6f */ | |
566 | ||
567 | static bool sysrq_down; | |
568 | static int sysrq_alt_use; | |
569 | static int sysrq_alt; | |
570 | ||
571 | static bool sysrq_filter(struct input_handle *handle, unsigned int type, | |
572 | unsigned int code, int value) | |
573 | { | |
574 | if (type != EV_KEY) | |
575 | goto out; | |
576 | ||
577 | switch (code) { | |
578 | ||
579 | case KEY_LEFTALT: | |
580 | case KEY_RIGHTALT: | |
581 | if (value) | |
582 | sysrq_alt = code; | |
583 | else if (sysrq_down && code == sysrq_alt_use) | |
584 | sysrq_down = false; | |
585 | break; | |
586 | ||
587 | case KEY_SYSRQ: | |
588 | if (value == 1 && sysrq_alt) { | |
589 | sysrq_down = true; | |
590 | sysrq_alt_use = sysrq_alt; | |
591 | } | |
592 | break; | |
593 | ||
594 | default: | |
595 | if (sysrq_down && value && value != 2) | |
596 | __handle_sysrq(sysrq_xlate[code], NULL, 1); | |
597 | break; | |
598 | } | |
599 | ||
600 | out: | |
601 | return sysrq_down; | |
602 | } | |
603 | ||
604 | static int sysrq_connect(struct input_handler *handler, | |
605 | struct input_dev *dev, | |
606 | const struct input_device_id *id) | |
607 | { | |
608 | struct input_handle *handle; | |
609 | int error; | |
610 | ||
611 | sysrq_down = false; | |
612 | sysrq_alt = 0; | |
613 | ||
614 | handle = kzalloc(sizeof(struct input_handle), GFP_KERNEL); | |
615 | if (!handle) | |
616 | return -ENOMEM; | |
617 | ||
618 | handle->dev = dev; | |
619 | handle->handler = handler; | |
620 | handle->name = "sysrq"; | |
621 | ||
622 | error = input_register_handle(handle); | |
623 | if (error) { | |
624 | pr_err("Failed to register input sysrq handler, error %d\n", | |
625 | error); | |
626 | goto err_free; | |
627 | } | |
628 | ||
629 | error = input_open_device(handle); | |
630 | if (error) { | |
631 | pr_err("Failed to open input device, error %d\n", error); | |
632 | goto err_unregister; | |
633 | } | |
634 | ||
635 | return 0; | |
636 | ||
637 | err_unregister: | |
638 | input_unregister_handle(handle); | |
639 | err_free: | |
640 | kfree(handle); | |
641 | return error; | |
642 | } | |
643 | ||
644 | static void sysrq_disconnect(struct input_handle *handle) | |
645 | { | |
646 | input_close_device(handle); | |
647 | input_unregister_handle(handle); | |
648 | kfree(handle); | |
649 | } | |
650 | ||
651 | /* | |
652 | * We are matching on KEY_LEFTALT insteard of KEY_SYSRQ because not all | |
653 | * keyboards have SysRq ikey predefined and so user may add it to keymap | |
654 | * later, but we expect all such keyboards to have left alt. | |
655 | */ | |
656 | static const struct input_device_id sysrq_ids[] = { | |
657 | { | |
658 | .flags = INPUT_DEVICE_ID_MATCH_EVBIT | | |
659 | INPUT_DEVICE_ID_MATCH_KEYBIT, | |
660 | .evbit = { BIT_MASK(EV_KEY) }, | |
661 | .keybit = { BIT_MASK(KEY_LEFTALT) }, | |
662 | }, | |
663 | { }, | |
664 | }; | |
665 | ||
666 | static struct input_handler sysrq_handler = { | |
667 | .filter = sysrq_filter, | |
668 | .connect = sysrq_connect, | |
669 | .disconnect = sysrq_disconnect, | |
670 | .name = "sysrq", | |
671 | .id_table = sysrq_ids, | |
672 | }; | |
673 | ||
674 | static bool sysrq_handler_registered; | |
675 | ||
676 | static inline void sysrq_register_handler(void) | |
677 | { | |
678 | int error; | |
679 | ||
680 | error = input_register_handler(&sysrq_handler); | |
681 | if (error) | |
682 | pr_err("Failed to register input handler, error %d", error); | |
683 | else | |
684 | sysrq_handler_registered = true; | |
685 | } | |
686 | ||
687 | static inline void sysrq_unregister_handler(void) | |
688 | { | |
689 | if (sysrq_handler_registered) { | |
690 | input_unregister_handler(&sysrq_handler); | |
691 | sysrq_handler_registered = false; | |
692 | } | |
693 | } | |
694 | ||
695 | #else | |
696 | ||
697 | static inline void sysrq_register_handler(void) | |
698 | { | |
699 | } | |
700 | ||
701 | static inline void sysrq_unregister_handler(void) | |
702 | { | |
703 | } | |
704 | ||
705 | #endif /* CONFIG_INPUT */ | |
706 | ||
707 | int sysrq_toggle_support(int enable_mask) | |
708 | { | |
709 | bool was_enabled = sysrq_on(); | |
710 | ||
711 | sysrq_enabled = enable_mask; | |
712 | ||
713 | if (was_enabled != sysrq_on()) { | |
714 | if (sysrq_on()) | |
715 | sysrq_register_handler(); | |
716 | else | |
717 | sysrq_unregister_handler(); | |
718 | } | |
719 | ||
720 | return 0; | |
721 | } | |
722 | ||
cf62ddce | 723 | static int __sysrq_swap_key_ops(int key, struct sysrq_key_op *insert_op_p, |
bf36b901 AM |
724 | struct sysrq_key_op *remove_op_p) |
725 | { | |
1da177e4 LT |
726 | int retval; |
727 | unsigned long flags; | |
728 | ||
729 | spin_lock_irqsave(&sysrq_key_table_lock, flags); | |
730 | if (__sysrq_get_key_op(key) == remove_op_p) { | |
731 | __sysrq_put_key_op(key, insert_op_p); | |
732 | retval = 0; | |
733 | } else { | |
734 | retval = -1; | |
735 | } | |
736 | spin_unlock_irqrestore(&sysrq_key_table_lock, flags); | |
1da177e4 LT |
737 | return retval; |
738 | } | |
739 | ||
740 | int register_sysrq_key(int key, struct sysrq_key_op *op_p) | |
741 | { | |
742 | return __sysrq_swap_key_ops(key, op_p, NULL); | |
743 | } | |
bf36b901 | 744 | EXPORT_SYMBOL(register_sysrq_key); |
1da177e4 LT |
745 | |
746 | int unregister_sysrq_key(int key, struct sysrq_key_op *op_p) | |
747 | { | |
748 | return __sysrq_swap_key_ops(key, NULL, op_p); | |
749 | } | |
1da177e4 | 750 | EXPORT_SYMBOL(unregister_sysrq_key); |
f40cbaa5 AD |
751 | |
752 | #ifdef CONFIG_PROC_FS | |
753 | /* | |
754 | * writing 'C' to /proc/sysrq-trigger is like sysrq-C | |
755 | */ | |
756 | static ssize_t write_sysrq_trigger(struct file *file, const char __user *buf, | |
757 | size_t count, loff_t *ppos) | |
758 | { | |
759 | if (count) { | |
760 | char c; | |
761 | ||
762 | if (get_user(c, buf)) | |
763 | return -EFAULT; | |
764 | __handle_sysrq(c, NULL, 0); | |
765 | } | |
97f5f0cd | 766 | |
f40cbaa5 AD |
767 | return count; |
768 | } | |
769 | ||
770 | static const struct file_operations proc_sysrq_trigger_operations = { | |
771 | .write = write_sysrq_trigger, | |
772 | }; | |
773 | ||
97f5f0cd DT |
774 | static void sysrq_init_procfs(void) |
775 | { | |
776 | if (!proc_create("sysrq-trigger", S_IWUSR, NULL, | |
777 | &proc_sysrq_trigger_operations)) | |
778 | pr_err("Failed to register proc interface\n"); | |
779 | } | |
780 | ||
781 | #else | |
782 | ||
783 | static inline void sysrq_init_procfs(void) | |
784 | { | |
785 | } | |
786 | ||
787 | #endif /* CONFIG_PROC_FS */ | |
788 | ||
f40cbaa5 AD |
789 | static int __init sysrq_init(void) |
790 | { | |
97f5f0cd DT |
791 | sysrq_init_procfs(); |
792 | ||
793 | if (sysrq_on()) | |
794 | sysrq_register_handler(); | |
795 | ||
f40cbaa5 AD |
796 | return 0; |
797 | } | |
798 | module_init(sysrq_init); |