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> | |
1da177e4 LT |
35 | #include <linux/swap.h> |
36 | #include <linux/spinlock.h> | |
37 | #include <linux/vt_kern.h> | |
38 | #include <linux/workqueue.h> | |
88ad0bf6 | 39 | #include <linux/hrtimer.h> |
5a3135c2 | 40 | #include <linux/oom.h> |
5a0e3ad6 | 41 | #include <linux/slab.h> |
97f5f0cd | 42 | #include <linux/input.h> |
ff01bb48 | 43 | #include <linux/uaccess.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 */ | |
8c6a98b2 | 49 | static int __read_mostly sysrq_enabled = SYSRQ_DEFAULT_ENABLE; |
97f5f0cd | 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 | 112 | { |
079c9534 | 113 | vt_reset_unicode(fg_console); |
1da177e4 | 114 | } |
079c9534 | 115 | |
1da177e4 LT |
116 | static struct sysrq_key_op sysrq_unraw_op = { |
117 | .handler = sysrq_handle_unraw, | |
118 | .help_msg = "unRaw", | |
2e8ecb9d | 119 | .action_msg = "Keyboard mode set to system default", |
1da177e4 LT |
120 | .enable_mask = SYSRQ_ENABLE_KEYBOARD, |
121 | }; | |
bf36b901 | 122 | #else |
97f5f0cd | 123 | #define sysrq_unraw_op (*(struct sysrq_key_op *)NULL) |
1da177e4 LT |
124 | #endif /* CONFIG_VT */ |
125 | ||
1495cc9d | 126 | static void sysrq_handle_crash(int key) |
86b1ae38 | 127 | { |
d6580a9f | 128 | char *killer = NULL; |
cab8bd34 HS |
129 | |
130 | panic_on_oops = 1; /* force panic */ | |
131 | wmb(); | |
d6580a9f | 132 | *killer = 1; |
86b1ae38 | 133 | } |
cab8bd34 | 134 | static struct sysrq_key_op sysrq_crash_op = { |
d6580a9f NH |
135 | .handler = sysrq_handle_crash, |
136 | .help_msg = "Crash", | |
137 | .action_msg = "Trigger a crash", | |
86b1ae38 HN |
138 | .enable_mask = SYSRQ_ENABLE_DUMP, |
139 | }; | |
86b1ae38 | 140 | |
1495cc9d | 141 | static void sysrq_handle_reboot(int key) |
1da177e4 | 142 | { |
b2e9c7d0 | 143 | lockdep_off(); |
1da177e4 | 144 | local_irq_enable(); |
4de8b9b7 | 145 | emergency_restart(); |
1da177e4 | 146 | } |
1da177e4 LT |
147 | static struct sysrq_key_op sysrq_reboot_op = { |
148 | .handler = sysrq_handle_reboot, | |
149 | .help_msg = "reBoot", | |
150 | .action_msg = "Resetting", | |
151 | .enable_mask = SYSRQ_ENABLE_BOOT, | |
152 | }; | |
153 | ||
1495cc9d | 154 | static void sysrq_handle_sync(int key) |
1da177e4 LT |
155 | { |
156 | emergency_sync(); | |
157 | } | |
1da177e4 LT |
158 | static struct sysrq_key_op sysrq_sync_op = { |
159 | .handler = sysrq_handle_sync, | |
160 | .help_msg = "Sync", | |
161 | .action_msg = "Emergency Sync", | |
162 | .enable_mask = SYSRQ_ENABLE_SYNC, | |
163 | }; | |
164 | ||
1495cc9d | 165 | static void sysrq_handle_show_timers(int key) |
88ad0bf6 IM |
166 | { |
167 | sysrq_timer_list_show(); | |
168 | } | |
169 | ||
170 | static struct sysrq_key_op sysrq_show_timers_op = { | |
171 | .handler = sysrq_handle_show_timers, | |
172 | .help_msg = "show-all-timers(Q)", | |
322acf65 | 173 | .action_msg = "Show clockevent devices & pending hrtimers (no others)", |
88ad0bf6 IM |
174 | }; |
175 | ||
1495cc9d | 176 | static void sysrq_handle_mountro(int key) |
1da177e4 LT |
177 | { |
178 | emergency_remount(); | |
179 | } | |
1da177e4 LT |
180 | static struct sysrq_key_op sysrq_mountro_op = { |
181 | .handler = sysrq_handle_mountro, | |
182 | .help_msg = "Unmount", | |
183 | .action_msg = "Emergency Remount R/O", | |
184 | .enable_mask = SYSRQ_ENABLE_REMOUNT, | |
185 | }; | |
186 | ||
8c64580d | 187 | #ifdef CONFIG_LOCKDEP |
1495cc9d | 188 | static void sysrq_handle_showlocks(int key) |
de5097c2 | 189 | { |
9a11b49a | 190 | debug_show_all_locks(); |
de5097c2 | 191 | } |
8c64580d | 192 | |
de5097c2 IM |
193 | static struct sysrq_key_op sysrq_showlocks_op = { |
194 | .handler = sysrq_handle_showlocks, | |
195 | .help_msg = "show-all-locks(D)", | |
196 | .action_msg = "Show Locks Held", | |
197 | }; | |
bf36b901 | 198 | #else |
97f5f0cd | 199 | #define sysrq_showlocks_op (*(struct sysrq_key_op *)NULL) |
de5097c2 | 200 | #endif |
1da177e4 | 201 | |
5045bcae RR |
202 | #ifdef CONFIG_SMP |
203 | static DEFINE_SPINLOCK(show_lock); | |
204 | ||
205 | static void showacpu(void *dummy) | |
206 | { | |
207 | unsigned long flags; | |
208 | ||
209 | /* Idle CPUs have no interesting backtrace. */ | |
210 | if (idle_cpu(smp_processor_id())) | |
211 | return; | |
212 | ||
213 | spin_lock_irqsave(&show_lock, flags); | |
214 | printk(KERN_INFO "CPU%d:\n", smp_processor_id()); | |
215 | show_stack(NULL, NULL); | |
216 | spin_unlock_irqrestore(&show_lock, flags); | |
217 | } | |
218 | ||
219 | static void sysrq_showregs_othercpus(struct work_struct *dummy) | |
220 | { | |
8b604d52 | 221 | smp_call_function(showacpu, NULL, 0); |
5045bcae RR |
222 | } |
223 | ||
224 | static DECLARE_WORK(sysrq_showallcpus, sysrq_showregs_othercpus); | |
225 | ||
1495cc9d | 226 | static void sysrq_handle_showallcpus(int key) |
5045bcae | 227 | { |
47cab6a7 IM |
228 | /* |
229 | * Fall back to the workqueue based printing if the | |
230 | * backtrace printing did not succeed or the | |
231 | * architecture has no support for it: | |
232 | */ | |
233 | if (!trigger_all_cpu_backtrace()) { | |
234 | struct pt_regs *regs = get_irq_regs(); | |
235 | ||
236 | if (regs) { | |
237 | printk(KERN_INFO "CPU%d:\n", smp_processor_id()); | |
238 | show_regs(regs); | |
239 | } | |
240 | schedule_work(&sysrq_showallcpus); | |
241 | } | |
5045bcae RR |
242 | } |
243 | ||
244 | static struct sysrq_key_op sysrq_showallcpus_op = { | |
245 | .handler = sysrq_handle_showallcpus, | |
208b95ce | 246 | .help_msg = "show-backtrace-all-active-cpus(L)", |
5045bcae RR |
247 | .action_msg = "Show backtrace of all active CPUs", |
248 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
249 | }; | |
250 | #endif | |
251 | ||
1495cc9d | 252 | static void sysrq_handle_showregs(int key) |
1da177e4 | 253 | { |
7d12e780 DH |
254 | struct pt_regs *regs = get_irq_regs(); |
255 | if (regs) | |
256 | show_regs(regs); | |
cdd6c482 | 257 | perf_event_print_debug(); |
1da177e4 LT |
258 | } |
259 | static struct sysrq_key_op sysrq_showregs_op = { | |
260 | .handler = sysrq_handle_showregs, | |
208b95ce | 261 | .help_msg = "show-registers(P)", |
1da177e4 LT |
262 | .action_msg = "Show Regs", |
263 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
264 | }; | |
265 | ||
1495cc9d | 266 | static void sysrq_handle_showstate(int key) |
1da177e4 LT |
267 | { |
268 | show_state(); | |
269 | } | |
270 | static struct sysrq_key_op sysrq_showstate_op = { | |
271 | .handler = sysrq_handle_showstate, | |
208b95ce | 272 | .help_msg = "show-task-states(T)", |
1da177e4 LT |
273 | .action_msg = "Show State", |
274 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
275 | }; | |
276 | ||
1495cc9d | 277 | static void sysrq_handle_showstate_blocked(int key) |
e59e2ae2 IM |
278 | { |
279 | show_state_filter(TASK_UNINTERRUPTIBLE); | |
280 | } | |
281 | static struct sysrq_key_op sysrq_showstate_blocked_op = { | |
282 | .handler = sysrq_handle_showstate_blocked, | |
208b95ce | 283 | .help_msg = "show-blocked-tasks(W)", |
e59e2ae2 IM |
284 | .action_msg = "Show Blocked State", |
285 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
286 | }; | |
287 | ||
69f698ad PZ |
288 | #ifdef CONFIG_TRACING |
289 | #include <linux/ftrace.h> | |
290 | ||
1495cc9d | 291 | static void sysrq_ftrace_dump(int key) |
69f698ad | 292 | { |
cecbca96 | 293 | ftrace_dump(DUMP_ALL); |
69f698ad PZ |
294 | } |
295 | static struct sysrq_key_op sysrq_ftrace_dump_op = { | |
296 | .handler = sysrq_ftrace_dump, | |
3871f2ff | 297 | .help_msg = "dump-ftrace-buffer(Z)", |
69f698ad PZ |
298 | .action_msg = "Dump ftrace buffer", |
299 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
300 | }; | |
301 | #else | |
97f5f0cd | 302 | #define sysrq_ftrace_dump_op (*(struct sysrq_key_op *)NULL) |
69f698ad | 303 | #endif |
e59e2ae2 | 304 | |
1495cc9d | 305 | static void sysrq_handle_showmem(int key) |
1da177e4 | 306 | { |
b2b755b5 | 307 | show_mem(0); |
1da177e4 LT |
308 | } |
309 | static struct sysrq_key_op sysrq_showmem_op = { | |
310 | .handler = sysrq_handle_showmem, | |
208b95ce | 311 | .help_msg = "show-memory-usage(M)", |
1da177e4 LT |
312 | .action_msg = "Show Memory", |
313 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
314 | }; | |
315 | ||
bf36b901 AM |
316 | /* |
317 | * Signal sysrq helper function. Sends a signal to all user processes. | |
318 | */ | |
1da177e4 LT |
319 | static void send_sig_all(int sig) |
320 | { | |
321 | struct task_struct *p; | |
322 | ||
e502babe | 323 | read_lock(&tasklist_lock); |
1da177e4 | 324 | for_each_process(p) { |
d3a532a9 AV |
325 | if (p->flags & PF_KTHREAD) |
326 | continue; | |
327 | if (is_global_init(p)) | |
328 | continue; | |
329 | ||
b82c3287 | 330 | do_send_sig_info(sig, SEND_SIG_FORCED, p, true); |
1da177e4 | 331 | } |
e502babe | 332 | read_unlock(&tasklist_lock); |
1da177e4 LT |
333 | } |
334 | ||
1495cc9d | 335 | static void sysrq_handle_term(int key) |
1da177e4 LT |
336 | { |
337 | send_sig_all(SIGTERM); | |
338 | console_loglevel = 8; | |
339 | } | |
340 | static struct sysrq_key_op sysrq_term_op = { | |
341 | .handler = sysrq_handle_term, | |
208b95ce | 342 | .help_msg = "terminate-all-tasks(E)", |
1da177e4 LT |
343 | .action_msg = "Terminate All Tasks", |
344 | .enable_mask = SYSRQ_ENABLE_SIGNAL, | |
345 | }; | |
346 | ||
65f27f38 | 347 | static void moom_callback(struct work_struct *ignored) |
1da177e4 | 348 | { |
08ab9b10 | 349 | out_of_memory(node_zonelist(0, GFP_KERNEL), GFP_KERNEL, 0, NULL, true); |
1da177e4 LT |
350 | } |
351 | ||
65f27f38 | 352 | static DECLARE_WORK(moom_work, moom_callback); |
1da177e4 | 353 | |
1495cc9d | 354 | static void sysrq_handle_moom(int key) |
1da177e4 LT |
355 | { |
356 | schedule_work(&moom_work); | |
357 | } | |
358 | static struct sysrq_key_op sysrq_moom_op = { | |
359 | .handler = sysrq_handle_moom, | |
208b95ce | 360 | .help_msg = "memory-full-oom-kill(F)", |
1da177e4 | 361 | .action_msg = "Manual OOM execution", |
b4236f81 | 362 | .enable_mask = SYSRQ_ENABLE_SIGNAL, |
1da177e4 LT |
363 | }; |
364 | ||
c2d75438 | 365 | #ifdef CONFIG_BLOCK |
1495cc9d | 366 | static void sysrq_handle_thaw(int key) |
c2d75438 ES |
367 | { |
368 | emergency_thaw_all(); | |
369 | } | |
370 | static struct sysrq_key_op sysrq_thaw_op = { | |
371 | .handler = sysrq_handle_thaw, | |
372 | .help_msg = "thaw-filesystems(J)", | |
373 | .action_msg = "Emergency Thaw of all frozen filesystems", | |
374 | .enable_mask = SYSRQ_ENABLE_SIGNAL, | |
375 | }; | |
376 | #endif | |
377 | ||
1495cc9d | 378 | static void sysrq_handle_kill(int key) |
1da177e4 LT |
379 | { |
380 | send_sig_all(SIGKILL); | |
381 | console_loglevel = 8; | |
382 | } | |
383 | static struct sysrq_key_op sysrq_kill_op = { | |
384 | .handler = sysrq_handle_kill, | |
208b95ce | 385 | .help_msg = "kill-all-tasks(I)", |
1da177e4 LT |
386 | .action_msg = "Kill All Tasks", |
387 | .enable_mask = SYSRQ_ENABLE_SIGNAL, | |
388 | }; | |
389 | ||
1495cc9d | 390 | static void sysrq_handle_unrt(int key) |
1da177e4 LT |
391 | { |
392 | normalize_rt_tasks(); | |
393 | } | |
394 | static struct sysrq_key_op sysrq_unrt_op = { | |
395 | .handler = sysrq_handle_unrt, | |
208b95ce | 396 | .help_msg = "nice-all-RT-tasks(N)", |
1da177e4 LT |
397 | .action_msg = "Nice All RT Tasks", |
398 | .enable_mask = SYSRQ_ENABLE_RTNICE, | |
399 | }; | |
400 | ||
401 | /* Key Operations table and lock */ | |
402 | static DEFINE_SPINLOCK(sysrq_key_table_lock); | |
bf36b901 AM |
403 | |
404 | static struct sysrq_key_op *sysrq_key_table[36] = { | |
405 | &sysrq_loglevel_op, /* 0 */ | |
406 | &sysrq_loglevel_op, /* 1 */ | |
407 | &sysrq_loglevel_op, /* 2 */ | |
408 | &sysrq_loglevel_op, /* 3 */ | |
409 | &sysrq_loglevel_op, /* 4 */ | |
410 | &sysrq_loglevel_op, /* 5 */ | |
411 | &sysrq_loglevel_op, /* 6 */ | |
412 | &sysrq_loglevel_op, /* 7 */ | |
413 | &sysrq_loglevel_op, /* 8 */ | |
414 | &sysrq_loglevel_op, /* 9 */ | |
415 | ||
416 | /* | |
d346cce3 RD |
417 | * a: Don't use for system provided sysrqs, it is handled specially on |
418 | * sparc and will never arrive. | |
bf36b901 AM |
419 | */ |
420 | NULL, /* a */ | |
421 | &sysrq_reboot_op, /* b */ | |
cab8bd34 | 422 | &sysrq_crash_op, /* c & ibm_emac driver debug */ |
bf36b901 AM |
423 | &sysrq_showlocks_op, /* d */ |
424 | &sysrq_term_op, /* e */ | |
425 | &sysrq_moom_op, /* f */ | |
364b5b7b | 426 | /* g: May be registered for the kernel debugger */ |
bf36b901 | 427 | NULL, /* g */ |
c2d75438 | 428 | NULL, /* h - reserved for help */ |
bf36b901 | 429 | &sysrq_kill_op, /* i */ |
c2d75438 ES |
430 | #ifdef CONFIG_BLOCK |
431 | &sysrq_thaw_op, /* j */ | |
432 | #else | |
bf36b901 | 433 | NULL, /* j */ |
c2d75438 | 434 | #endif |
bf36b901 | 435 | &sysrq_SAK_op, /* k */ |
5045bcae RR |
436 | #ifdef CONFIG_SMP |
437 | &sysrq_showallcpus_op, /* l */ | |
438 | #else | |
bf36b901 | 439 | NULL, /* l */ |
5045bcae | 440 | #endif |
bf36b901 AM |
441 | &sysrq_showmem_op, /* m */ |
442 | &sysrq_unrt_op, /* n */ | |
d346cce3 | 443 | /* o: This will often be registered as 'Off' at init time */ |
bf36b901 AM |
444 | NULL, /* o */ |
445 | &sysrq_showregs_op, /* p */ | |
88ad0bf6 | 446 | &sysrq_show_timers_op, /* q */ |
d346cce3 | 447 | &sysrq_unraw_op, /* r */ |
bf36b901 AM |
448 | &sysrq_sync_op, /* s */ |
449 | &sysrq_showstate_op, /* t */ | |
450 | &sysrq_mountro_op, /* u */ | |
364b5b7b | 451 | /* v: May be registered for frame buffer console restore */ |
bf36b901 | 452 | NULL, /* v */ |
d346cce3 RD |
453 | &sysrq_showstate_blocked_op, /* w */ |
454 | /* x: May be registered on ppc/powerpc for xmon */ | |
455 | NULL, /* x */ | |
93dae5b7 | 456 | /* y: May be registered on sparc64 for global register dump */ |
bf36b901 | 457 | NULL, /* y */ |
69f698ad | 458 | &sysrq_ftrace_dump_op, /* z */ |
1da177e4 LT |
459 | }; |
460 | ||
461 | /* key2index calculation, -1 on invalid index */ | |
bf36b901 AM |
462 | static int sysrq_key_table_key2index(int key) |
463 | { | |
1da177e4 | 464 | int retval; |
bf36b901 AM |
465 | |
466 | if ((key >= '0') && (key <= '9')) | |
1da177e4 | 467 | retval = key - '0'; |
bf36b901 | 468 | else if ((key >= 'a') && (key <= 'z')) |
1da177e4 | 469 | retval = key + 10 - 'a'; |
bf36b901 | 470 | else |
1da177e4 | 471 | retval = -1; |
1da177e4 LT |
472 | return retval; |
473 | } | |
474 | ||
475 | /* | |
476 | * get and put functions for the table, exposed to modules. | |
477 | */ | |
bf36b901 AM |
478 | struct sysrq_key_op *__sysrq_get_key_op(int key) |
479 | { | |
480 | struct sysrq_key_op *op_p = NULL; | |
1da177e4 | 481 | int i; |
bf36b901 | 482 | |
1da177e4 | 483 | i = sysrq_key_table_key2index(key); |
bf36b901 AM |
484 | if (i != -1) |
485 | op_p = sysrq_key_table[i]; | |
97f5f0cd | 486 | |
1da177e4 LT |
487 | return op_p; |
488 | } | |
489 | ||
bf36b901 AM |
490 | static void __sysrq_put_key_op(int key, struct sysrq_key_op *op_p) |
491 | { | |
492 | int i = sysrq_key_table_key2index(key); | |
1da177e4 | 493 | |
1da177e4 LT |
494 | if (i != -1) |
495 | sysrq_key_table[i] = op_p; | |
496 | } | |
497 | ||
f335397d | 498 | void __handle_sysrq(int key, bool check_mask) |
1da177e4 LT |
499 | { |
500 | struct sysrq_key_op *op_p; | |
501 | int orig_log_level; | |
bf36b901 | 502 | int i; |
1da177e4 LT |
503 | unsigned long flags; |
504 | ||
505 | spin_lock_irqsave(&sysrq_key_table_lock, flags); | |
fb144adc AW |
506 | /* |
507 | * Raise the apparent loglevel to maximum so that the sysrq header | |
508 | * is shown to provide the user with positive feedback. We do not | |
509 | * simply emit this at KERN_EMERG as that would change message | |
510 | * routing in the consumers of /proc/kmsg. | |
511 | */ | |
1da177e4 LT |
512 | orig_log_level = console_loglevel; |
513 | console_loglevel = 7; | |
514 | printk(KERN_INFO "SysRq : "); | |
515 | ||
516 | op_p = __sysrq_get_key_op(key); | |
517 | if (op_p) { | |
bf36b901 AM |
518 | /* |
519 | * Should we check for enabled operations (/proc/sysrq-trigger | |
520 | * should not) and is the invoked operation enabled? | |
521 | */ | |
5d6f647f | 522 | if (!check_mask || sysrq_on_mask(op_p->enable_mask)) { |
bf36b901 | 523 | printk("%s\n", op_p->action_msg); |
1da177e4 | 524 | console_loglevel = orig_log_level; |
1495cc9d | 525 | op_p->handler(key); |
bf36b901 | 526 | } else { |
1da177e4 | 527 | printk("This sysrq operation is disabled.\n"); |
bf36b901 | 528 | } |
1da177e4 LT |
529 | } else { |
530 | printk("HELP : "); | |
531 | /* Only print the help msg once per handler */ | |
bf36b901 AM |
532 | for (i = 0; i < ARRAY_SIZE(sysrq_key_table); i++) { |
533 | if (sysrq_key_table[i]) { | |
534 | int j; | |
535 | ||
536 | for (j = 0; sysrq_key_table[i] != | |
537 | sysrq_key_table[j]; j++) | |
538 | ; | |
539 | if (j != i) | |
540 | continue; | |
541 | printk("%s ", sysrq_key_table[i]->help_msg); | |
542 | } | |
1da177e4 | 543 | } |
bf36b901 | 544 | printk("\n"); |
1da177e4 LT |
545 | console_loglevel = orig_log_level; |
546 | } | |
547 | spin_unlock_irqrestore(&sysrq_key_table_lock, flags); | |
548 | } | |
549 | ||
f335397d | 550 | void handle_sysrq(int key) |
1da177e4 | 551 | { |
5d6f647f | 552 | if (sysrq_on()) |
f335397d | 553 | __handle_sysrq(key, true); |
1da177e4 | 554 | } |
bf36b901 | 555 | EXPORT_SYMBOL(handle_sysrq); |
1da177e4 | 556 | |
97f5f0cd DT |
557 | #ifdef CONFIG_INPUT |
558 | ||
559 | /* Simple translation table for the SysRq keys */ | |
fcb71930 | 560 | static const unsigned char sysrq_xlate[KEY_CNT] = |
97f5f0cd DT |
561 | "\000\0331234567890-=\177\t" /* 0x00 - 0x0f */ |
562 | "qwertyuiop[]\r\000as" /* 0x10 - 0x1f */ | |
563 | "dfghjkl;'`\000\\zxcv" /* 0x20 - 0x2f */ | |
564 | "bnm,./\000*\000 \000\201\202\203\204\205" /* 0x30 - 0x3f */ | |
565 | "\206\207\210\211\212\000\000789-456+1" /* 0x40 - 0x4f */ | |
566 | "230\177\000\000\213\214\000\000\000\000\000\000\000\000\000\000" /* 0x50 - 0x5f */ | |
567 | "\r\000/"; /* 0x60 - 0x6f */ | |
568 | ||
fcb71930 DT |
569 | struct sysrq_state { |
570 | struct input_handle handle; | |
571 | struct work_struct reinject_work; | |
572 | unsigned long key_down[BITS_TO_LONGS(KEY_CNT)]; | |
573 | unsigned int alt; | |
574 | unsigned int alt_use; | |
575 | bool active; | |
576 | bool need_reinject; | |
7ab7b5ad | 577 | bool reinjecting; |
fcb71930 DT |
578 | }; |
579 | ||
580 | static void sysrq_reinject_alt_sysrq(struct work_struct *work) | |
581 | { | |
582 | struct sysrq_state *sysrq = | |
583 | container_of(work, struct sysrq_state, reinject_work); | |
584 | struct input_handle *handle = &sysrq->handle; | |
585 | unsigned int alt_code = sysrq->alt_use; | |
586 | ||
587 | if (sysrq->need_reinject) { | |
7ab7b5ad DT |
588 | /* we do not want the assignment to be reordered */ |
589 | sysrq->reinjecting = true; | |
590 | mb(); | |
591 | ||
fcb71930 DT |
592 | /* Simulate press and release of Alt + SysRq */ |
593 | input_inject_event(handle, EV_KEY, alt_code, 1); | |
594 | input_inject_event(handle, EV_KEY, KEY_SYSRQ, 1); | |
595 | input_inject_event(handle, EV_SYN, SYN_REPORT, 1); | |
596 | ||
597 | input_inject_event(handle, EV_KEY, KEY_SYSRQ, 0); | |
598 | input_inject_event(handle, EV_KEY, alt_code, 0); | |
599 | input_inject_event(handle, EV_SYN, SYN_REPORT, 1); | |
7ab7b5ad DT |
600 | |
601 | mb(); | |
602 | sysrq->reinjecting = false; | |
fcb71930 DT |
603 | } |
604 | } | |
97f5f0cd | 605 | |
fcb71930 DT |
606 | static bool sysrq_filter(struct input_handle *handle, |
607 | unsigned int type, unsigned int code, int value) | |
97f5f0cd | 608 | { |
fcb71930 DT |
609 | struct sysrq_state *sysrq = handle->private; |
610 | bool was_active = sysrq->active; | |
1966cb22 DT |
611 | bool suppress; |
612 | ||
7ab7b5ad DT |
613 | /* |
614 | * Do not filter anything if we are in the process of re-injecting | |
615 | * Alt+SysRq combination. | |
616 | */ | |
617 | if (sysrq->reinjecting) | |
618 | return false; | |
619 | ||
fcb71930 | 620 | switch (type) { |
1966cb22 | 621 | |
fcb71930 DT |
622 | case EV_SYN: |
623 | suppress = false; | |
624 | break; | |
97f5f0cd | 625 | |
fcb71930 DT |
626 | case EV_KEY: |
627 | switch (code) { | |
97f5f0cd | 628 | |
fcb71930 DT |
629 | case KEY_LEFTALT: |
630 | case KEY_RIGHTALT: | |
631 | if (!value) { | |
632 | /* One of ALTs is being released */ | |
633 | if (sysrq->active && code == sysrq->alt_use) | |
634 | sysrq->active = false; | |
f5dec511 | 635 | |
fcb71930 DT |
636 | sysrq->alt = KEY_RESERVED; |
637 | ||
638 | } else if (value != 2) { | |
639 | sysrq->alt = code; | |
640 | sysrq->need_reinject = false; | |
641 | } | |
642 | break; | |
643 | ||
644 | case KEY_SYSRQ: | |
645 | if (value == 1 && sysrq->alt != KEY_RESERVED) { | |
646 | sysrq->active = true; | |
647 | sysrq->alt_use = sysrq->alt; | |
648 | /* | |
649 | * If nothing else will be pressed we'll need | |
7ab7b5ad | 650 | * to re-inject Alt-SysRq keysroke. |
fcb71930 DT |
651 | */ |
652 | sysrq->need_reinject = true; | |
653 | } | |
654 | ||
655 | /* | |
656 | * Pretend that sysrq was never pressed at all. This | |
657 | * is needed to properly handle KGDB which will try | |
658 | * to release all keys after exiting debugger. If we | |
659 | * do not clear key bit it KGDB will end up sending | |
660 | * release events for Alt and SysRq, potentially | |
661 | * triggering print screen function. | |
662 | */ | |
663 | if (sysrq->active) | |
664 | clear_bit(KEY_SYSRQ, handle->dev->key); | |
665 | ||
666 | break; | |
667 | ||
668 | default: | |
669 | if (sysrq->active && value && value != 2) { | |
670 | sysrq->need_reinject = false; | |
671 | __handle_sysrq(sysrq_xlate[code], true); | |
672 | } | |
673 | break; | |
f5dec511 | 674 | } |
97f5f0cd | 675 | |
fcb71930 DT |
676 | suppress = sysrq->active; |
677 | ||
678 | if (!sysrq->active) { | |
679 | /* | |
680 | * If we are not suppressing key presses keep track of | |
681 | * keyboard state so we can release keys that have been | |
682 | * pressed before entering SysRq mode. | |
683 | */ | |
684 | if (value) | |
685 | set_bit(code, sysrq->key_down); | |
686 | else | |
687 | clear_bit(code, sysrq->key_down); | |
688 | ||
689 | if (was_active) | |
690 | schedule_work(&sysrq->reinject_work); | |
691 | ||
692 | } else if (value == 0 && | |
693 | test_and_clear_bit(code, sysrq->key_down)) { | |
694 | /* | |
695 | * Pass on release events for keys that was pressed before | |
696 | * entering SysRq mode. | |
697 | */ | |
698 | suppress = false; | |
97f5f0cd DT |
699 | } |
700 | break; | |
701 | ||
702 | default: | |
fcb71930 | 703 | suppress = sysrq->active; |
97f5f0cd DT |
704 | break; |
705 | } | |
706 | ||
1966cb22 | 707 | return suppress; |
97f5f0cd DT |
708 | } |
709 | ||
710 | static int sysrq_connect(struct input_handler *handler, | |
711 | struct input_dev *dev, | |
712 | const struct input_device_id *id) | |
713 | { | |
fcb71930 | 714 | struct sysrq_state *sysrq; |
97f5f0cd DT |
715 | int error; |
716 | ||
fcb71930 DT |
717 | sysrq = kzalloc(sizeof(struct sysrq_state), GFP_KERNEL); |
718 | if (!sysrq) | |
97f5f0cd DT |
719 | return -ENOMEM; |
720 | ||
fcb71930 DT |
721 | INIT_WORK(&sysrq->reinject_work, sysrq_reinject_alt_sysrq); |
722 | ||
723 | sysrq->handle.dev = dev; | |
724 | sysrq->handle.handler = handler; | |
725 | sysrq->handle.name = "sysrq"; | |
726 | sysrq->handle.private = sysrq; | |
97f5f0cd | 727 | |
fcb71930 | 728 | error = input_register_handle(&sysrq->handle); |
97f5f0cd DT |
729 | if (error) { |
730 | pr_err("Failed to register input sysrq handler, error %d\n", | |
731 | error); | |
732 | goto err_free; | |
733 | } | |
734 | ||
fcb71930 | 735 | error = input_open_device(&sysrq->handle); |
97f5f0cd DT |
736 | if (error) { |
737 | pr_err("Failed to open input device, error %d\n", error); | |
738 | goto err_unregister; | |
739 | } | |
740 | ||
741 | return 0; | |
742 | ||
743 | err_unregister: | |
fcb71930 | 744 | input_unregister_handle(&sysrq->handle); |
97f5f0cd | 745 | err_free: |
fcb71930 | 746 | kfree(sysrq); |
97f5f0cd DT |
747 | return error; |
748 | } | |
749 | ||
750 | static void sysrq_disconnect(struct input_handle *handle) | |
751 | { | |
fcb71930 DT |
752 | struct sysrq_state *sysrq = handle->private; |
753 | ||
97f5f0cd | 754 | input_close_device(handle); |
fcb71930 | 755 | cancel_work_sync(&sysrq->reinject_work); |
97f5f0cd | 756 | input_unregister_handle(handle); |
fcb71930 | 757 | kfree(sysrq); |
97f5f0cd DT |
758 | } |
759 | ||
760 | /* | |
1966cb22 DT |
761 | * We are matching on KEY_LEFTALT instead of KEY_SYSRQ because not all |
762 | * keyboards have SysRq key predefined and so user may add it to keymap | |
97f5f0cd DT |
763 | * later, but we expect all such keyboards to have left alt. |
764 | */ | |
765 | static const struct input_device_id sysrq_ids[] = { | |
766 | { | |
767 | .flags = INPUT_DEVICE_ID_MATCH_EVBIT | | |
768 | INPUT_DEVICE_ID_MATCH_KEYBIT, | |
769 | .evbit = { BIT_MASK(EV_KEY) }, | |
770 | .keybit = { BIT_MASK(KEY_LEFTALT) }, | |
771 | }, | |
772 | { }, | |
773 | }; | |
774 | ||
775 | static struct input_handler sysrq_handler = { | |
776 | .filter = sysrq_filter, | |
777 | .connect = sysrq_connect, | |
778 | .disconnect = sysrq_disconnect, | |
779 | .name = "sysrq", | |
780 | .id_table = sysrq_ids, | |
781 | }; | |
782 | ||
783 | static bool sysrq_handler_registered; | |
784 | ||
785 | static inline void sysrq_register_handler(void) | |
786 | { | |
787 | int error; | |
788 | ||
789 | error = input_register_handler(&sysrq_handler); | |
790 | if (error) | |
791 | pr_err("Failed to register input handler, error %d", error); | |
792 | else | |
793 | sysrq_handler_registered = true; | |
794 | } | |
795 | ||
796 | static inline void sysrq_unregister_handler(void) | |
797 | { | |
798 | if (sysrq_handler_registered) { | |
799 | input_unregister_handler(&sysrq_handler); | |
800 | sysrq_handler_registered = false; | |
801 | } | |
802 | } | |
803 | ||
804 | #else | |
805 | ||
806 | static inline void sysrq_register_handler(void) | |
807 | { | |
808 | } | |
809 | ||
810 | static inline void sysrq_unregister_handler(void) | |
811 | { | |
812 | } | |
813 | ||
814 | #endif /* CONFIG_INPUT */ | |
815 | ||
816 | int sysrq_toggle_support(int enable_mask) | |
817 | { | |
818 | bool was_enabled = sysrq_on(); | |
819 | ||
820 | sysrq_enabled = enable_mask; | |
821 | ||
822 | if (was_enabled != sysrq_on()) { | |
823 | if (sysrq_on()) | |
824 | sysrq_register_handler(); | |
825 | else | |
826 | sysrq_unregister_handler(); | |
827 | } | |
828 | ||
829 | return 0; | |
830 | } | |
831 | ||
cf62ddce | 832 | static int __sysrq_swap_key_ops(int key, struct sysrq_key_op *insert_op_p, |
bf36b901 AM |
833 | struct sysrq_key_op *remove_op_p) |
834 | { | |
1da177e4 LT |
835 | int retval; |
836 | unsigned long flags; | |
837 | ||
838 | spin_lock_irqsave(&sysrq_key_table_lock, flags); | |
839 | if (__sysrq_get_key_op(key) == remove_op_p) { | |
840 | __sysrq_put_key_op(key, insert_op_p); | |
841 | retval = 0; | |
842 | } else { | |
843 | retval = -1; | |
844 | } | |
845 | spin_unlock_irqrestore(&sysrq_key_table_lock, flags); | |
1da177e4 LT |
846 | return retval; |
847 | } | |
848 | ||
849 | int register_sysrq_key(int key, struct sysrq_key_op *op_p) | |
850 | { | |
851 | return __sysrq_swap_key_ops(key, op_p, NULL); | |
852 | } | |
bf36b901 | 853 | EXPORT_SYMBOL(register_sysrq_key); |
1da177e4 LT |
854 | |
855 | int unregister_sysrq_key(int key, struct sysrq_key_op *op_p) | |
856 | { | |
857 | return __sysrq_swap_key_ops(key, NULL, op_p); | |
858 | } | |
1da177e4 | 859 | EXPORT_SYMBOL(unregister_sysrq_key); |
f40cbaa5 AD |
860 | |
861 | #ifdef CONFIG_PROC_FS | |
862 | /* | |
863 | * writing 'C' to /proc/sysrq-trigger is like sysrq-C | |
864 | */ | |
865 | static ssize_t write_sysrq_trigger(struct file *file, const char __user *buf, | |
866 | size_t count, loff_t *ppos) | |
867 | { | |
868 | if (count) { | |
869 | char c; | |
870 | ||
871 | if (get_user(c, buf)) | |
872 | return -EFAULT; | |
f335397d | 873 | __handle_sysrq(c, false); |
f40cbaa5 | 874 | } |
97f5f0cd | 875 | |
f40cbaa5 AD |
876 | return count; |
877 | } | |
878 | ||
879 | static const struct file_operations proc_sysrq_trigger_operations = { | |
880 | .write = write_sysrq_trigger, | |
6038f373 | 881 | .llseek = noop_llseek, |
f40cbaa5 AD |
882 | }; |
883 | ||
97f5f0cd DT |
884 | static void sysrq_init_procfs(void) |
885 | { | |
886 | if (!proc_create("sysrq-trigger", S_IWUSR, NULL, | |
887 | &proc_sysrq_trigger_operations)) | |
888 | pr_err("Failed to register proc interface\n"); | |
889 | } | |
890 | ||
891 | #else | |
892 | ||
893 | static inline void sysrq_init_procfs(void) | |
894 | { | |
895 | } | |
896 | ||
897 | #endif /* CONFIG_PROC_FS */ | |
898 | ||
f40cbaa5 AD |
899 | static int __init sysrq_init(void) |
900 | { | |
97f5f0cd DT |
901 | sysrq_init_procfs(); |
902 | ||
903 | if (sysrq_on()) | |
904 | sysrq_register_handler(); | |
905 | ||
f40cbaa5 AD |
906 | return 0; |
907 | } | |
908 | module_init(sysrq_init); |