Commit | Line | Data |
---|---|---|
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> | |
1da177e4 LT |
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> | |
f40cbaa5 | 27 | #include <linux/proc_fs.h> |
c1dc0b9c | 28 | #include <linux/nmi.h> |
1da177e4 | 29 | #include <linux/quotaops.h> |
cdd6c482 | 30 | #include <linux/perf_event.h> |
1da177e4 LT |
31 | #include <linux/kernel.h> |
32 | #include <linux/module.h> | |
33 | #include <linux/suspend.h> | |
34 | #include <linux/writeback.h> | |
35 | #include <linux/buffer_head.h> /* for fsync_bdev() */ | |
36 | #include <linux/swap.h> | |
37 | #include <linux/spinlock.h> | |
38 | #include <linux/vt_kern.h> | |
39 | #include <linux/workqueue.h> | |
88ad0bf6 | 40 | #include <linux/hrtimer.h> |
5a3135c2 | 41 | #include <linux/oom.h> |
5a0e3ad6 | 42 | #include <linux/slab.h> |
97f5f0cd | 43 | #include <linux/input.h> |
1da177e4 LT |
44 | |
45 | #include <asm/ptrace.h> | |
2033b0c3 | 46 | #include <asm/irq_regs.h> |
1da177e4 LT |
47 | |
48 | /* Whether we react on sysrq keys or just ignore them */ | |
97f5f0cd DT |
49 | static int __read_mostly sysrq_enabled = 1; |
50 | static bool __read_mostly sysrq_always_enabled; | |
5d6f647f | 51 | |
97f5f0cd | 52 | static bool sysrq_on(void) |
5d6f647f | 53 | { |
97f5f0cd | 54 | return sysrq_enabled || sysrq_always_enabled; |
5d6f647f IM |
55 | } |
56 | ||
57 | /* | |
58 | * A value of 1 means 'all', other nonzero values are an op mask: | |
59 | */ | |
97f5f0cd | 60 | static bool sysrq_on_mask(int mask) |
5d6f647f | 61 | { |
97f5f0cd DT |
62 | return sysrq_always_enabled || |
63 | sysrq_enabled == 1 || | |
64 | (sysrq_enabled & mask); | |
5d6f647f IM |
65 | } |
66 | ||
67 | static int __init sysrq_always_enabled_setup(char *str) | |
68 | { | |
97f5f0cd DT |
69 | sysrq_always_enabled = true; |
70 | pr_info("sysrq always enabled.\n"); | |
5d6f647f IM |
71 | |
72 | return 1; | |
73 | } | |
74 | ||
75 | __setup("sysrq_always_enabled", sysrq_always_enabled_setup); | |
76 | ||
1da177e4 | 77 | |
1495cc9d | 78 | static void sysrq_handle_loglevel(int key) |
1da177e4 LT |
79 | { |
80 | int i; | |
97f5f0cd | 81 | |
1da177e4 LT |
82 | i = key - '0'; |
83 | console_loglevel = 7; | |
84 | printk("Loglevel set to %d\n", i); | |
85 | console_loglevel = i; | |
bf36b901 | 86 | } |
1da177e4 LT |
87 | static struct sysrq_key_op sysrq_loglevel_op = { |
88 | .handler = sysrq_handle_loglevel, | |
208b95ce | 89 | .help_msg = "loglevel(0-9)", |
1da177e4 LT |
90 | .action_msg = "Changing Loglevel", |
91 | .enable_mask = SYSRQ_ENABLE_LOG, | |
92 | }; | |
93 | ||
1da177e4 | 94 | #ifdef CONFIG_VT |
1495cc9d | 95 | static void sysrq_handle_SAK(int key) |
1da177e4 | 96 | { |
8b6312f4 | 97 | struct work_struct *SAK_work = &vc_cons[fg_console].SAK_work; |
8b6312f4 | 98 | schedule_work(SAK_work); |
1da177e4 LT |
99 | } |
100 | static struct sysrq_key_op sysrq_SAK_op = { | |
101 | .handler = sysrq_handle_SAK, | |
102 | .help_msg = "saK", | |
103 | .action_msg = "SAK", | |
104 | .enable_mask = SYSRQ_ENABLE_KEYBOARD, | |
105 | }; | |
bf36b901 | 106 | #else |
97f5f0cd | 107 | #define sysrq_SAK_op (*(struct sysrq_key_op *)NULL) |
1da177e4 LT |
108 | #endif |
109 | ||
110 | #ifdef CONFIG_VT | |
1495cc9d | 111 | static void sysrq_handle_unraw(int key) |
1da177e4 LT |
112 | { |
113 | struct kbd_struct *kbd = &kbd_table[fg_console]; | |
114 | ||
115 | if (kbd) | |
2e8ecb9d | 116 | kbd->kbdmode = default_utf8 ? VC_UNICODE : VC_XLATE; |
1da177e4 LT |
117 | } |
118 | static struct sysrq_key_op sysrq_unraw_op = { | |
119 | .handler = sysrq_handle_unraw, | |
120 | .help_msg = "unRaw", | |
2e8ecb9d | 121 | .action_msg = "Keyboard mode set to system default", |
1da177e4 LT |
122 | .enable_mask = SYSRQ_ENABLE_KEYBOARD, |
123 | }; | |
bf36b901 | 124 | #else |
97f5f0cd | 125 | #define sysrq_unraw_op (*(struct sysrq_key_op *)NULL) |
1da177e4 LT |
126 | #endif /* CONFIG_VT */ |
127 | ||
1495cc9d | 128 | static void sysrq_handle_crash(int key) |
86b1ae38 | 129 | { |
d6580a9f | 130 | char *killer = NULL; |
cab8bd34 HS |
131 | |
132 | panic_on_oops = 1; /* force panic */ | |
133 | wmb(); | |
d6580a9f | 134 | *killer = 1; |
86b1ae38 | 135 | } |
cab8bd34 | 136 | static struct sysrq_key_op sysrq_crash_op = { |
d6580a9f NH |
137 | .handler = sysrq_handle_crash, |
138 | .help_msg = "Crash", | |
139 | .action_msg = "Trigger a crash", | |
86b1ae38 HN |
140 | .enable_mask = SYSRQ_ENABLE_DUMP, |
141 | }; | |
86b1ae38 | 142 | |
1495cc9d | 143 | static void sysrq_handle_reboot(int key) |
1da177e4 | 144 | { |
b2e9c7d0 | 145 | lockdep_off(); |
1da177e4 | 146 | local_irq_enable(); |
4de8b9b7 | 147 | emergency_restart(); |
1da177e4 | 148 | } |
1da177e4 LT |
149 | static struct sysrq_key_op sysrq_reboot_op = { |
150 | .handler = sysrq_handle_reboot, | |
151 | .help_msg = "reBoot", | |
152 | .action_msg = "Resetting", | |
153 | .enable_mask = SYSRQ_ENABLE_BOOT, | |
154 | }; | |
155 | ||
1495cc9d | 156 | static void sysrq_handle_sync(int key) |
1da177e4 LT |
157 | { |
158 | emergency_sync(); | |
159 | } | |
1da177e4 LT |
160 | static struct sysrq_key_op sysrq_sync_op = { |
161 | .handler = sysrq_handle_sync, | |
162 | .help_msg = "Sync", | |
163 | .action_msg = "Emergency Sync", | |
164 | .enable_mask = SYSRQ_ENABLE_SYNC, | |
165 | }; | |
166 | ||
1495cc9d | 167 | static void sysrq_handle_show_timers(int key) |
88ad0bf6 IM |
168 | { |
169 | sysrq_timer_list_show(); | |
170 | } | |
171 | ||
172 | static struct sysrq_key_op sysrq_show_timers_op = { | |
173 | .handler = sysrq_handle_show_timers, | |
174 | .help_msg = "show-all-timers(Q)", | |
322acf65 | 175 | .action_msg = "Show clockevent devices & pending hrtimers (no others)", |
88ad0bf6 IM |
176 | }; |
177 | ||
1495cc9d | 178 | static void sysrq_handle_mountro(int key) |
1da177e4 LT |
179 | { |
180 | emergency_remount(); | |
181 | } | |
1da177e4 LT |
182 | static struct sysrq_key_op sysrq_mountro_op = { |
183 | .handler = sysrq_handle_mountro, | |
184 | .help_msg = "Unmount", | |
185 | .action_msg = "Emergency Remount R/O", | |
186 | .enable_mask = SYSRQ_ENABLE_REMOUNT, | |
187 | }; | |
188 | ||
8c64580d | 189 | #ifdef CONFIG_LOCKDEP |
1495cc9d | 190 | static void sysrq_handle_showlocks(int key) |
de5097c2 | 191 | { |
9a11b49a | 192 | debug_show_all_locks(); |
de5097c2 | 193 | } |
8c64580d | 194 | |
de5097c2 IM |
195 | static struct sysrq_key_op sysrq_showlocks_op = { |
196 | .handler = sysrq_handle_showlocks, | |
197 | .help_msg = "show-all-locks(D)", | |
198 | .action_msg = "Show Locks Held", | |
199 | }; | |
bf36b901 | 200 | #else |
97f5f0cd | 201 | #define sysrq_showlocks_op (*(struct sysrq_key_op *)NULL) |
de5097c2 | 202 | #endif |
1da177e4 | 203 | |
5045bcae RR |
204 | #ifdef CONFIG_SMP |
205 | static DEFINE_SPINLOCK(show_lock); | |
206 | ||
207 | static void showacpu(void *dummy) | |
208 | { | |
209 | unsigned long flags; | |
210 | ||
211 | /* Idle CPUs have no interesting backtrace. */ | |
212 | if (idle_cpu(smp_processor_id())) | |
213 | return; | |
214 | ||
215 | spin_lock_irqsave(&show_lock, flags); | |
216 | printk(KERN_INFO "CPU%d:\n", smp_processor_id()); | |
217 | show_stack(NULL, NULL); | |
218 | spin_unlock_irqrestore(&show_lock, flags); | |
219 | } | |
220 | ||
221 | static void sysrq_showregs_othercpus(struct work_struct *dummy) | |
222 | { | |
8b604d52 | 223 | smp_call_function(showacpu, NULL, 0); |
5045bcae RR |
224 | } |
225 | ||
226 | static DECLARE_WORK(sysrq_showallcpus, sysrq_showregs_othercpus); | |
227 | ||
1495cc9d | 228 | static void sysrq_handle_showallcpus(int key) |
5045bcae | 229 | { |
47cab6a7 IM |
230 | /* |
231 | * Fall back to the workqueue based printing if the | |
232 | * backtrace printing did not succeed or the | |
233 | * architecture has no support for it: | |
234 | */ | |
235 | if (!trigger_all_cpu_backtrace()) { | |
236 | struct pt_regs *regs = get_irq_regs(); | |
237 | ||
238 | if (regs) { | |
239 | printk(KERN_INFO "CPU%d:\n", smp_processor_id()); | |
240 | show_regs(regs); | |
241 | } | |
242 | schedule_work(&sysrq_showallcpus); | |
243 | } | |
5045bcae RR |
244 | } |
245 | ||
246 | static struct sysrq_key_op sysrq_showallcpus_op = { | |
247 | .handler = sysrq_handle_showallcpus, | |
208b95ce | 248 | .help_msg = "show-backtrace-all-active-cpus(L)", |
5045bcae RR |
249 | .action_msg = "Show backtrace of all active CPUs", |
250 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
251 | }; | |
252 | #endif | |
253 | ||
1495cc9d | 254 | static void sysrq_handle_showregs(int key) |
1da177e4 | 255 | { |
7d12e780 DH |
256 | struct pt_regs *regs = get_irq_regs(); |
257 | if (regs) | |
258 | show_regs(regs); | |
cdd6c482 | 259 | perf_event_print_debug(); |
1da177e4 LT |
260 | } |
261 | static struct sysrq_key_op sysrq_showregs_op = { | |
262 | .handler = sysrq_handle_showregs, | |
208b95ce | 263 | .help_msg = "show-registers(P)", |
1da177e4 LT |
264 | .action_msg = "Show Regs", |
265 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
266 | }; | |
267 | ||
1495cc9d | 268 | static void sysrq_handle_showstate(int key) |
1da177e4 LT |
269 | { |
270 | show_state(); | |
271 | } | |
272 | static struct sysrq_key_op sysrq_showstate_op = { | |
273 | .handler = sysrq_handle_showstate, | |
208b95ce | 274 | .help_msg = "show-task-states(T)", |
1da177e4 LT |
275 | .action_msg = "Show State", |
276 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
277 | }; | |
278 | ||
1495cc9d | 279 | static void sysrq_handle_showstate_blocked(int key) |
e59e2ae2 IM |
280 | { |
281 | show_state_filter(TASK_UNINTERRUPTIBLE); | |
282 | } | |
283 | static struct sysrq_key_op sysrq_showstate_blocked_op = { | |
284 | .handler = sysrq_handle_showstate_blocked, | |
208b95ce | 285 | .help_msg = "show-blocked-tasks(W)", |
e59e2ae2 IM |
286 | .action_msg = "Show Blocked State", |
287 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
288 | }; | |
289 | ||
69f698ad PZ |
290 | #ifdef CONFIG_TRACING |
291 | #include <linux/ftrace.h> | |
292 | ||
1495cc9d | 293 | static void sysrq_ftrace_dump(int key) |
69f698ad | 294 | { |
cecbca96 | 295 | ftrace_dump(DUMP_ALL); |
69f698ad PZ |
296 | } |
297 | static struct sysrq_key_op sysrq_ftrace_dump_op = { | |
298 | .handler = sysrq_ftrace_dump, | |
3871f2ff | 299 | .help_msg = "dump-ftrace-buffer(Z)", |
69f698ad PZ |
300 | .action_msg = "Dump ftrace buffer", |
301 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
302 | }; | |
303 | #else | |
97f5f0cd | 304 | #define sysrq_ftrace_dump_op (*(struct sysrq_key_op *)NULL) |
69f698ad | 305 | #endif |
e59e2ae2 | 306 | |
1495cc9d | 307 | static void sysrq_handle_showmem(int key) |
1da177e4 LT |
308 | { |
309 | show_mem(); | |
310 | } | |
311 | static struct sysrq_key_op sysrq_showmem_op = { | |
312 | .handler = sysrq_handle_showmem, | |
208b95ce | 313 | .help_msg = "show-memory-usage(M)", |
1da177e4 LT |
314 | .action_msg = "Show Memory", |
315 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
316 | }; | |
317 | ||
bf36b901 AM |
318 | /* |
319 | * Signal sysrq helper function. Sends a signal to all user processes. | |
320 | */ | |
1da177e4 LT |
321 | static void send_sig_all(int sig) |
322 | { | |
323 | struct task_struct *p; | |
324 | ||
325 | for_each_process(p) { | |
b460cbc5 | 326 | if (p->mm && !is_global_init(p)) |
1da177e4 LT |
327 | /* Not swapper, init nor kernel thread */ |
328 | force_sig(sig, p); | |
329 | } | |
330 | } | |
331 | ||
1495cc9d | 332 | static void sysrq_handle_term(int key) |
1da177e4 LT |
333 | { |
334 | send_sig_all(SIGTERM); | |
335 | console_loglevel = 8; | |
336 | } | |
337 | static struct sysrq_key_op sysrq_term_op = { | |
338 | .handler = sysrq_handle_term, | |
208b95ce | 339 | .help_msg = "terminate-all-tasks(E)", |
1da177e4 LT |
340 | .action_msg = "Terminate All Tasks", |
341 | .enable_mask = SYSRQ_ENABLE_SIGNAL, | |
342 | }; | |
343 | ||
65f27f38 | 344 | static void moom_callback(struct work_struct *ignored) |
1da177e4 | 345 | { |
4365a567 | 346 | out_of_memory(node_zonelist(0, GFP_KERNEL), GFP_KERNEL, 0, NULL); |
1da177e4 LT |
347 | } |
348 | ||
65f27f38 | 349 | static DECLARE_WORK(moom_work, moom_callback); |
1da177e4 | 350 | |
1495cc9d | 351 | static void sysrq_handle_moom(int key) |
1da177e4 LT |
352 | { |
353 | schedule_work(&moom_work); | |
354 | } | |
355 | static struct sysrq_key_op sysrq_moom_op = { | |
356 | .handler = sysrq_handle_moom, | |
208b95ce | 357 | .help_msg = "memory-full-oom-kill(F)", |
1da177e4 | 358 | .action_msg = "Manual OOM execution", |
b4236f81 | 359 | .enable_mask = SYSRQ_ENABLE_SIGNAL, |
1da177e4 LT |
360 | }; |
361 | ||
c2d75438 | 362 | #ifdef CONFIG_BLOCK |
1495cc9d | 363 | static void sysrq_handle_thaw(int key) |
c2d75438 ES |
364 | { |
365 | emergency_thaw_all(); | |
366 | } | |
367 | static struct sysrq_key_op sysrq_thaw_op = { | |
368 | .handler = sysrq_handle_thaw, | |
369 | .help_msg = "thaw-filesystems(J)", | |
370 | .action_msg = "Emergency Thaw of all frozen filesystems", | |
371 | .enable_mask = SYSRQ_ENABLE_SIGNAL, | |
372 | }; | |
373 | #endif | |
374 | ||
1495cc9d | 375 | static void sysrq_handle_kill(int key) |
1da177e4 LT |
376 | { |
377 | send_sig_all(SIGKILL); | |
378 | console_loglevel = 8; | |
379 | } | |
380 | static struct sysrq_key_op sysrq_kill_op = { | |
381 | .handler = sysrq_handle_kill, | |
208b95ce | 382 | .help_msg = "kill-all-tasks(I)", |
1da177e4 LT |
383 | .action_msg = "Kill All Tasks", |
384 | .enable_mask = SYSRQ_ENABLE_SIGNAL, | |
385 | }; | |
386 | ||
1495cc9d | 387 | static void sysrq_handle_unrt(int key) |
1da177e4 LT |
388 | { |
389 | normalize_rt_tasks(); | |
390 | } | |
391 | static struct sysrq_key_op sysrq_unrt_op = { | |
392 | .handler = sysrq_handle_unrt, | |
208b95ce | 393 | .help_msg = "nice-all-RT-tasks(N)", |
1da177e4 LT |
394 | .action_msg = "Nice All RT Tasks", |
395 | .enable_mask = SYSRQ_ENABLE_RTNICE, | |
396 | }; | |
397 | ||
398 | /* Key Operations table and lock */ | |
399 | static DEFINE_SPINLOCK(sysrq_key_table_lock); | |
bf36b901 AM |
400 | |
401 | static struct sysrq_key_op *sysrq_key_table[36] = { | |
402 | &sysrq_loglevel_op, /* 0 */ | |
403 | &sysrq_loglevel_op, /* 1 */ | |
404 | &sysrq_loglevel_op, /* 2 */ | |
405 | &sysrq_loglevel_op, /* 3 */ | |
406 | &sysrq_loglevel_op, /* 4 */ | |
407 | &sysrq_loglevel_op, /* 5 */ | |
408 | &sysrq_loglevel_op, /* 6 */ | |
409 | &sysrq_loglevel_op, /* 7 */ | |
410 | &sysrq_loglevel_op, /* 8 */ | |
411 | &sysrq_loglevel_op, /* 9 */ | |
412 | ||
413 | /* | |
d346cce3 RD |
414 | * a: Don't use for system provided sysrqs, it is handled specially on |
415 | * sparc and will never arrive. | |
bf36b901 AM |
416 | */ |
417 | NULL, /* a */ | |
418 | &sysrq_reboot_op, /* b */ | |
cab8bd34 | 419 | &sysrq_crash_op, /* c & ibm_emac driver debug */ |
bf36b901 AM |
420 | &sysrq_showlocks_op, /* d */ |
421 | &sysrq_term_op, /* e */ | |
422 | &sysrq_moom_op, /* f */ | |
364b5b7b | 423 | /* g: May be registered for the kernel debugger */ |
bf36b901 | 424 | NULL, /* g */ |
c2d75438 | 425 | NULL, /* h - reserved for help */ |
bf36b901 | 426 | &sysrq_kill_op, /* i */ |
c2d75438 ES |
427 | #ifdef CONFIG_BLOCK |
428 | &sysrq_thaw_op, /* j */ | |
429 | #else | |
bf36b901 | 430 | NULL, /* j */ |
c2d75438 | 431 | #endif |
bf36b901 | 432 | &sysrq_SAK_op, /* k */ |
5045bcae RR |
433 | #ifdef CONFIG_SMP |
434 | &sysrq_showallcpus_op, /* l */ | |
435 | #else | |
bf36b901 | 436 | NULL, /* l */ |
5045bcae | 437 | #endif |
bf36b901 AM |
438 | &sysrq_showmem_op, /* m */ |
439 | &sysrq_unrt_op, /* n */ | |
d346cce3 | 440 | /* o: This will often be registered as 'Off' at init time */ |
bf36b901 AM |
441 | NULL, /* o */ |
442 | &sysrq_showregs_op, /* p */ | |
88ad0bf6 | 443 | &sysrq_show_timers_op, /* q */ |
d346cce3 | 444 | &sysrq_unraw_op, /* r */ |
bf36b901 AM |
445 | &sysrq_sync_op, /* s */ |
446 | &sysrq_showstate_op, /* t */ | |
447 | &sysrq_mountro_op, /* u */ | |
364b5b7b | 448 | /* v: May be registered for frame buffer console restore */ |
bf36b901 | 449 | NULL, /* v */ |
d346cce3 RD |
450 | &sysrq_showstate_blocked_op, /* w */ |
451 | /* x: May be registered on ppc/powerpc for xmon */ | |
452 | NULL, /* x */ | |
93dae5b7 | 453 | /* y: May be registered on sparc64 for global register dump */ |
bf36b901 | 454 | NULL, /* y */ |
69f698ad | 455 | &sysrq_ftrace_dump_op, /* z */ |
1da177e4 LT |
456 | }; |
457 | ||
458 | /* key2index calculation, -1 on invalid index */ | |
bf36b901 AM |
459 | static int sysrq_key_table_key2index(int key) |
460 | { | |
1da177e4 | 461 | int retval; |
bf36b901 AM |
462 | |
463 | if ((key >= '0') && (key <= '9')) | |
1da177e4 | 464 | retval = key - '0'; |
bf36b901 | 465 | else if ((key >= 'a') && (key <= 'z')) |
1da177e4 | 466 | retval = key + 10 - 'a'; |
bf36b901 | 467 | else |
1da177e4 | 468 | retval = -1; |
1da177e4 LT |
469 | return retval; |
470 | } | |
471 | ||
472 | /* | |
473 | * get and put functions for the table, exposed to modules. | |
474 | */ | |
bf36b901 AM |
475 | struct sysrq_key_op *__sysrq_get_key_op(int key) |
476 | { | |
477 | struct sysrq_key_op *op_p = NULL; | |
1da177e4 | 478 | int i; |
bf36b901 | 479 | |
1da177e4 | 480 | i = sysrq_key_table_key2index(key); |
bf36b901 AM |
481 | if (i != -1) |
482 | op_p = sysrq_key_table[i]; | |
97f5f0cd | 483 | |
1da177e4 LT |
484 | return op_p; |
485 | } | |
486 | ||
bf36b901 AM |
487 | static void __sysrq_put_key_op(int key, struct sysrq_key_op *op_p) |
488 | { | |
489 | int i = sysrq_key_table_key2index(key); | |
1da177e4 | 490 | |
1da177e4 LT |
491 | if (i != -1) |
492 | sysrq_key_table[i] = op_p; | |
493 | } | |
494 | ||
f335397d | 495 | void __handle_sysrq(int key, bool check_mask) |
1da177e4 LT |
496 | { |
497 | struct sysrq_key_op *op_p; | |
498 | int orig_log_level; | |
bf36b901 | 499 | int i; |
1da177e4 LT |
500 | unsigned long flags; |
501 | ||
502 | spin_lock_irqsave(&sysrq_key_table_lock, flags); | |
fb144adc AW |
503 | /* |
504 | * Raise the apparent loglevel to maximum so that the sysrq header | |
505 | * is shown to provide the user with positive feedback. We do not | |
506 | * simply emit this at KERN_EMERG as that would change message | |
507 | * routing in the consumers of /proc/kmsg. | |
508 | */ | |
1da177e4 LT |
509 | orig_log_level = console_loglevel; |
510 | console_loglevel = 7; | |
511 | printk(KERN_INFO "SysRq : "); | |
512 | ||
513 | op_p = __sysrq_get_key_op(key); | |
514 | if (op_p) { | |
bf36b901 AM |
515 | /* |
516 | * Should we check for enabled operations (/proc/sysrq-trigger | |
517 | * should not) and is the invoked operation enabled? | |
518 | */ | |
5d6f647f | 519 | if (!check_mask || sysrq_on_mask(op_p->enable_mask)) { |
bf36b901 | 520 | printk("%s\n", op_p->action_msg); |
1da177e4 | 521 | console_loglevel = orig_log_level; |
1495cc9d | 522 | op_p->handler(key); |
bf36b901 | 523 | } else { |
1da177e4 | 524 | printk("This sysrq operation is disabled.\n"); |
bf36b901 | 525 | } |
1da177e4 LT |
526 | } else { |
527 | printk("HELP : "); | |
528 | /* Only print the help msg once per handler */ | |
bf36b901 AM |
529 | for (i = 0; i < ARRAY_SIZE(sysrq_key_table); i++) { |
530 | if (sysrq_key_table[i]) { | |
531 | int j; | |
532 | ||
533 | for (j = 0; sysrq_key_table[i] != | |
534 | sysrq_key_table[j]; j++) | |
535 | ; | |
536 | if (j != i) | |
537 | continue; | |
538 | printk("%s ", sysrq_key_table[i]->help_msg); | |
539 | } | |
1da177e4 | 540 | } |
bf36b901 | 541 | printk("\n"); |
1da177e4 LT |
542 | console_loglevel = orig_log_level; |
543 | } | |
544 | spin_unlock_irqrestore(&sysrq_key_table_lock, flags); | |
545 | } | |
546 | ||
f335397d | 547 | void handle_sysrq(int key) |
1da177e4 | 548 | { |
5d6f647f | 549 | if (sysrq_on()) |
f335397d | 550 | __handle_sysrq(key, true); |
1da177e4 | 551 | } |
bf36b901 | 552 | EXPORT_SYMBOL(handle_sysrq); |
1da177e4 | 553 | |
97f5f0cd DT |
554 | #ifdef CONFIG_INPUT |
555 | ||
556 | /* Simple translation table for the SysRq keys */ | |
557 | static const unsigned char sysrq_xlate[KEY_MAX + 1] = | |
558 | "\000\0331234567890-=\177\t" /* 0x00 - 0x0f */ | |
559 | "qwertyuiop[]\r\000as" /* 0x10 - 0x1f */ | |
560 | "dfghjkl;'`\000\\zxcv" /* 0x20 - 0x2f */ | |
561 | "bnm,./\000*\000 \000\201\202\203\204\205" /* 0x30 - 0x3f */ | |
562 | "\206\207\210\211\212\000\000789-456+1" /* 0x40 - 0x4f */ | |
563 | "230\177\000\000\213\214\000\000\000\000\000\000\000\000\000\000" /* 0x50 - 0x5f */ | |
564 | "\r\000/"; /* 0x60 - 0x6f */ | |
565 | ||
566 | static bool sysrq_down; | |
567 | static int sysrq_alt_use; | |
568 | static int sysrq_alt; | |
1966cb22 | 569 | static DEFINE_SPINLOCK(sysrq_event_lock); |
97f5f0cd DT |
570 | |
571 | static bool sysrq_filter(struct input_handle *handle, unsigned int type, | |
572 | unsigned int code, int value) | |
573 | { | |
1966cb22 DT |
574 | bool suppress; |
575 | ||
576 | /* We are called with interrupts disabled, just take the lock */ | |
577 | spin_lock(&sysrq_event_lock); | |
578 | ||
97f5f0cd DT |
579 | if (type != EV_KEY) |
580 | goto out; | |
581 | ||
582 | switch (code) { | |
583 | ||
584 | case KEY_LEFTALT: | |
585 | case KEY_RIGHTALT: | |
586 | if (value) | |
587 | sysrq_alt = code; | |
f5dec511 DT |
588 | else { |
589 | if (sysrq_down && code == sysrq_alt_use) | |
590 | sysrq_down = false; | |
591 | ||
592 | sysrq_alt = 0; | |
593 | } | |
97f5f0cd DT |
594 | break; |
595 | ||
596 | case KEY_SYSRQ: | |
597 | if (value == 1 && sysrq_alt) { | |
598 | sysrq_down = true; | |
599 | sysrq_alt_use = sysrq_alt; | |
600 | } | |
601 | break; | |
602 | ||
603 | default: | |
604 | if (sysrq_down && value && value != 2) | |
f335397d | 605 | __handle_sysrq(sysrq_xlate[code], true); |
97f5f0cd DT |
606 | break; |
607 | } | |
608 | ||
609 | out: | |
1966cb22 DT |
610 | suppress = sysrq_down; |
611 | spin_unlock(&sysrq_event_lock); | |
612 | ||
613 | return suppress; | |
97f5f0cd DT |
614 | } |
615 | ||
616 | static int sysrq_connect(struct input_handler *handler, | |
617 | struct input_dev *dev, | |
618 | const struct input_device_id *id) | |
619 | { | |
620 | struct input_handle *handle; | |
621 | int error; | |
622 | ||
623 | sysrq_down = false; | |
624 | sysrq_alt = 0; | |
625 | ||
626 | handle = kzalloc(sizeof(struct input_handle), GFP_KERNEL); | |
627 | if (!handle) | |
628 | return -ENOMEM; | |
629 | ||
630 | handle->dev = dev; | |
631 | handle->handler = handler; | |
632 | handle->name = "sysrq"; | |
633 | ||
634 | error = input_register_handle(handle); | |
635 | if (error) { | |
636 | pr_err("Failed to register input sysrq handler, error %d\n", | |
637 | error); | |
638 | goto err_free; | |
639 | } | |
640 | ||
641 | error = input_open_device(handle); | |
642 | if (error) { | |
643 | pr_err("Failed to open input device, error %d\n", error); | |
644 | goto err_unregister; | |
645 | } | |
646 | ||
647 | return 0; | |
648 | ||
649 | err_unregister: | |
650 | input_unregister_handle(handle); | |
651 | err_free: | |
652 | kfree(handle); | |
653 | return error; | |
654 | } | |
655 | ||
656 | static void sysrq_disconnect(struct input_handle *handle) | |
657 | { | |
658 | input_close_device(handle); | |
659 | input_unregister_handle(handle); | |
660 | kfree(handle); | |
661 | } | |
662 | ||
663 | /* | |
1966cb22 DT |
664 | * We are matching on KEY_LEFTALT instead of KEY_SYSRQ because not all |
665 | * keyboards have SysRq key predefined and so user may add it to keymap | |
97f5f0cd DT |
666 | * later, but we expect all such keyboards to have left alt. |
667 | */ | |
668 | static const struct input_device_id sysrq_ids[] = { | |
669 | { | |
670 | .flags = INPUT_DEVICE_ID_MATCH_EVBIT | | |
671 | INPUT_DEVICE_ID_MATCH_KEYBIT, | |
672 | .evbit = { BIT_MASK(EV_KEY) }, | |
673 | .keybit = { BIT_MASK(KEY_LEFTALT) }, | |
674 | }, | |
675 | { }, | |
676 | }; | |
677 | ||
678 | static struct input_handler sysrq_handler = { | |
679 | .filter = sysrq_filter, | |
680 | .connect = sysrq_connect, | |
681 | .disconnect = sysrq_disconnect, | |
682 | .name = "sysrq", | |
683 | .id_table = sysrq_ids, | |
684 | }; | |
685 | ||
686 | static bool sysrq_handler_registered; | |
687 | ||
688 | static inline void sysrq_register_handler(void) | |
689 | { | |
690 | int error; | |
691 | ||
692 | error = input_register_handler(&sysrq_handler); | |
693 | if (error) | |
694 | pr_err("Failed to register input handler, error %d", error); | |
695 | else | |
696 | sysrq_handler_registered = true; | |
697 | } | |
698 | ||
699 | static inline void sysrq_unregister_handler(void) | |
700 | { | |
701 | if (sysrq_handler_registered) { | |
702 | input_unregister_handler(&sysrq_handler); | |
703 | sysrq_handler_registered = false; | |
704 | } | |
705 | } | |
706 | ||
707 | #else | |
708 | ||
709 | static inline void sysrq_register_handler(void) | |
710 | { | |
711 | } | |
712 | ||
713 | static inline void sysrq_unregister_handler(void) | |
714 | { | |
715 | } | |
716 | ||
717 | #endif /* CONFIG_INPUT */ | |
718 | ||
719 | int sysrq_toggle_support(int enable_mask) | |
720 | { | |
721 | bool was_enabled = sysrq_on(); | |
722 | ||
723 | sysrq_enabled = enable_mask; | |
724 | ||
725 | if (was_enabled != sysrq_on()) { | |
726 | if (sysrq_on()) | |
727 | sysrq_register_handler(); | |
728 | else | |
729 | sysrq_unregister_handler(); | |
730 | } | |
731 | ||
732 | return 0; | |
733 | } | |
734 | ||
cf62ddce | 735 | static int __sysrq_swap_key_ops(int key, struct sysrq_key_op *insert_op_p, |
bf36b901 AM |
736 | struct sysrq_key_op *remove_op_p) |
737 | { | |
1da177e4 LT |
738 | int retval; |
739 | unsigned long flags; | |
740 | ||
741 | spin_lock_irqsave(&sysrq_key_table_lock, flags); | |
742 | if (__sysrq_get_key_op(key) == remove_op_p) { | |
743 | __sysrq_put_key_op(key, insert_op_p); | |
744 | retval = 0; | |
745 | } else { | |
746 | retval = -1; | |
747 | } | |
748 | spin_unlock_irqrestore(&sysrq_key_table_lock, flags); | |
1da177e4 LT |
749 | return retval; |
750 | } | |
751 | ||
752 | int register_sysrq_key(int key, struct sysrq_key_op *op_p) | |
753 | { | |
754 | return __sysrq_swap_key_ops(key, op_p, NULL); | |
755 | } | |
bf36b901 | 756 | EXPORT_SYMBOL(register_sysrq_key); |
1da177e4 LT |
757 | |
758 | int unregister_sysrq_key(int key, struct sysrq_key_op *op_p) | |
759 | { | |
760 | return __sysrq_swap_key_ops(key, NULL, op_p); | |
761 | } | |
1da177e4 | 762 | EXPORT_SYMBOL(unregister_sysrq_key); |
f40cbaa5 AD |
763 | |
764 | #ifdef CONFIG_PROC_FS | |
765 | /* | |
766 | * writing 'C' to /proc/sysrq-trigger is like sysrq-C | |
767 | */ | |
768 | static ssize_t write_sysrq_trigger(struct file *file, const char __user *buf, | |
769 | size_t count, loff_t *ppos) | |
770 | { | |
771 | if (count) { | |
772 | char c; | |
773 | ||
774 | if (get_user(c, buf)) | |
775 | return -EFAULT; | |
f335397d | 776 | __handle_sysrq(c, false); |
f40cbaa5 | 777 | } |
97f5f0cd | 778 | |
f40cbaa5 AD |
779 | return count; |
780 | } | |
781 | ||
782 | static const struct file_operations proc_sysrq_trigger_operations = { | |
783 | .write = write_sysrq_trigger, | |
6038f373 | 784 | .llseek = noop_llseek, |
f40cbaa5 AD |
785 | }; |
786 | ||
97f5f0cd DT |
787 | static void sysrq_init_procfs(void) |
788 | { | |
789 | if (!proc_create("sysrq-trigger", S_IWUSR, NULL, | |
790 | &proc_sysrq_trigger_operations)) | |
791 | pr_err("Failed to register proc interface\n"); | |
792 | } | |
793 | ||
794 | #else | |
795 | ||
796 | static inline void sysrq_init_procfs(void) | |
797 | { | |
798 | } | |
799 | ||
800 | #endif /* CONFIG_PROC_FS */ | |
801 | ||
f40cbaa5 AD |
802 | static int __init sysrq_init(void) |
803 | { | |
97f5f0cd DT |
804 | sysrq_init_procfs(); |
805 | ||
806 | if (sysrq_on()) | |
807 | sysrq_register_handler(); | |
808 | ||
f40cbaa5 AD |
809 | return 0; |
810 | } | |
811 | module_init(sysrq_init); |