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 | { |
53186095 DR |
349 | out_of_memory(node_zonelist(first_online_node, GFP_KERNEL), GFP_KERNEL, |
350 | 0, NULL, true); | |
1da177e4 LT |
351 | } |
352 | ||
65f27f38 | 353 | static DECLARE_WORK(moom_work, moom_callback); |
1da177e4 | 354 | |
1495cc9d | 355 | static void sysrq_handle_moom(int key) |
1da177e4 LT |
356 | { |
357 | schedule_work(&moom_work); | |
358 | } | |
359 | static struct sysrq_key_op sysrq_moom_op = { | |
360 | .handler = sysrq_handle_moom, | |
208b95ce | 361 | .help_msg = "memory-full-oom-kill(F)", |
1da177e4 | 362 | .action_msg = "Manual OOM execution", |
b4236f81 | 363 | .enable_mask = SYSRQ_ENABLE_SIGNAL, |
1da177e4 LT |
364 | }; |
365 | ||
c2d75438 | 366 | #ifdef CONFIG_BLOCK |
1495cc9d | 367 | static void sysrq_handle_thaw(int key) |
c2d75438 ES |
368 | { |
369 | emergency_thaw_all(); | |
370 | } | |
371 | static struct sysrq_key_op sysrq_thaw_op = { | |
372 | .handler = sysrq_handle_thaw, | |
373 | .help_msg = "thaw-filesystems(J)", | |
374 | .action_msg = "Emergency Thaw of all frozen filesystems", | |
375 | .enable_mask = SYSRQ_ENABLE_SIGNAL, | |
376 | }; | |
377 | #endif | |
378 | ||
1495cc9d | 379 | static void sysrq_handle_kill(int key) |
1da177e4 LT |
380 | { |
381 | send_sig_all(SIGKILL); | |
382 | console_loglevel = 8; | |
383 | } | |
384 | static struct sysrq_key_op sysrq_kill_op = { | |
385 | .handler = sysrq_handle_kill, | |
208b95ce | 386 | .help_msg = "kill-all-tasks(I)", |
1da177e4 LT |
387 | .action_msg = "Kill All Tasks", |
388 | .enable_mask = SYSRQ_ENABLE_SIGNAL, | |
389 | }; | |
390 | ||
1495cc9d | 391 | static void sysrq_handle_unrt(int key) |
1da177e4 LT |
392 | { |
393 | normalize_rt_tasks(); | |
394 | } | |
395 | static struct sysrq_key_op sysrq_unrt_op = { | |
396 | .handler = sysrq_handle_unrt, | |
208b95ce | 397 | .help_msg = "nice-all-RT-tasks(N)", |
1da177e4 LT |
398 | .action_msg = "Nice All RT Tasks", |
399 | .enable_mask = SYSRQ_ENABLE_RTNICE, | |
400 | }; | |
401 | ||
402 | /* Key Operations table and lock */ | |
403 | static DEFINE_SPINLOCK(sysrq_key_table_lock); | |
bf36b901 AM |
404 | |
405 | static struct sysrq_key_op *sysrq_key_table[36] = { | |
406 | &sysrq_loglevel_op, /* 0 */ | |
407 | &sysrq_loglevel_op, /* 1 */ | |
408 | &sysrq_loglevel_op, /* 2 */ | |
409 | &sysrq_loglevel_op, /* 3 */ | |
410 | &sysrq_loglevel_op, /* 4 */ | |
411 | &sysrq_loglevel_op, /* 5 */ | |
412 | &sysrq_loglevel_op, /* 6 */ | |
413 | &sysrq_loglevel_op, /* 7 */ | |
414 | &sysrq_loglevel_op, /* 8 */ | |
415 | &sysrq_loglevel_op, /* 9 */ | |
416 | ||
417 | /* | |
d346cce3 RD |
418 | * a: Don't use for system provided sysrqs, it is handled specially on |
419 | * sparc and will never arrive. | |
bf36b901 AM |
420 | */ |
421 | NULL, /* a */ | |
422 | &sysrq_reboot_op, /* b */ | |
cab8bd34 | 423 | &sysrq_crash_op, /* c & ibm_emac driver debug */ |
bf36b901 AM |
424 | &sysrq_showlocks_op, /* d */ |
425 | &sysrq_term_op, /* e */ | |
426 | &sysrq_moom_op, /* f */ | |
364b5b7b | 427 | /* g: May be registered for the kernel debugger */ |
bf36b901 | 428 | NULL, /* g */ |
c2d75438 | 429 | NULL, /* h - reserved for help */ |
bf36b901 | 430 | &sysrq_kill_op, /* i */ |
c2d75438 ES |
431 | #ifdef CONFIG_BLOCK |
432 | &sysrq_thaw_op, /* j */ | |
433 | #else | |
bf36b901 | 434 | NULL, /* j */ |
c2d75438 | 435 | #endif |
bf36b901 | 436 | &sysrq_SAK_op, /* k */ |
5045bcae RR |
437 | #ifdef CONFIG_SMP |
438 | &sysrq_showallcpus_op, /* l */ | |
439 | #else | |
bf36b901 | 440 | NULL, /* l */ |
5045bcae | 441 | #endif |
bf36b901 AM |
442 | &sysrq_showmem_op, /* m */ |
443 | &sysrq_unrt_op, /* n */ | |
d346cce3 | 444 | /* o: This will often be registered as 'Off' at init time */ |
bf36b901 AM |
445 | NULL, /* o */ |
446 | &sysrq_showregs_op, /* p */ | |
88ad0bf6 | 447 | &sysrq_show_timers_op, /* q */ |
d346cce3 | 448 | &sysrq_unraw_op, /* r */ |
bf36b901 AM |
449 | &sysrq_sync_op, /* s */ |
450 | &sysrq_showstate_op, /* t */ | |
451 | &sysrq_mountro_op, /* u */ | |
364b5b7b | 452 | /* v: May be registered for frame buffer console restore */ |
bf36b901 | 453 | NULL, /* v */ |
d346cce3 RD |
454 | &sysrq_showstate_blocked_op, /* w */ |
455 | /* x: May be registered on ppc/powerpc for xmon */ | |
916ca14a | 456 | /* x: May be registered on sparc64 for global PMU dump */ |
d346cce3 | 457 | NULL, /* x */ |
93dae5b7 | 458 | /* y: May be registered on sparc64 for global register dump */ |
bf36b901 | 459 | NULL, /* y */ |
69f698ad | 460 | &sysrq_ftrace_dump_op, /* z */ |
1da177e4 LT |
461 | }; |
462 | ||
463 | /* key2index calculation, -1 on invalid index */ | |
bf36b901 AM |
464 | static int sysrq_key_table_key2index(int key) |
465 | { | |
1da177e4 | 466 | int retval; |
bf36b901 AM |
467 | |
468 | if ((key >= '0') && (key <= '9')) | |
1da177e4 | 469 | retval = key - '0'; |
bf36b901 | 470 | else if ((key >= 'a') && (key <= 'z')) |
1da177e4 | 471 | retval = key + 10 - 'a'; |
bf36b901 | 472 | else |
1da177e4 | 473 | retval = -1; |
1da177e4 LT |
474 | return retval; |
475 | } | |
476 | ||
477 | /* | |
478 | * get and put functions for the table, exposed to modules. | |
479 | */ | |
bf36b901 AM |
480 | struct sysrq_key_op *__sysrq_get_key_op(int key) |
481 | { | |
482 | struct sysrq_key_op *op_p = NULL; | |
1da177e4 | 483 | int i; |
bf36b901 | 484 | |
1da177e4 | 485 | i = sysrq_key_table_key2index(key); |
bf36b901 AM |
486 | if (i != -1) |
487 | op_p = sysrq_key_table[i]; | |
97f5f0cd | 488 | |
1da177e4 LT |
489 | return op_p; |
490 | } | |
491 | ||
bf36b901 AM |
492 | static void __sysrq_put_key_op(int key, struct sysrq_key_op *op_p) |
493 | { | |
494 | int i = sysrq_key_table_key2index(key); | |
1da177e4 | 495 | |
1da177e4 LT |
496 | if (i != -1) |
497 | sysrq_key_table[i] = op_p; | |
498 | } | |
499 | ||
f335397d | 500 | void __handle_sysrq(int key, bool check_mask) |
1da177e4 LT |
501 | { |
502 | struct sysrq_key_op *op_p; | |
503 | int orig_log_level; | |
bf36b901 | 504 | int i; |
1da177e4 LT |
505 | unsigned long flags; |
506 | ||
507 | spin_lock_irqsave(&sysrq_key_table_lock, flags); | |
fb144adc AW |
508 | /* |
509 | * Raise the apparent loglevel to maximum so that the sysrq header | |
510 | * is shown to provide the user with positive feedback. We do not | |
511 | * simply emit this at KERN_EMERG as that would change message | |
512 | * routing in the consumers of /proc/kmsg. | |
513 | */ | |
1da177e4 LT |
514 | orig_log_level = console_loglevel; |
515 | console_loglevel = 7; | |
516 | printk(KERN_INFO "SysRq : "); | |
517 | ||
518 | op_p = __sysrq_get_key_op(key); | |
519 | if (op_p) { | |
bf36b901 AM |
520 | /* |
521 | * Should we check for enabled operations (/proc/sysrq-trigger | |
522 | * should not) and is the invoked operation enabled? | |
523 | */ | |
5d6f647f | 524 | if (!check_mask || sysrq_on_mask(op_p->enable_mask)) { |
bf36b901 | 525 | printk("%s\n", op_p->action_msg); |
1da177e4 | 526 | console_loglevel = orig_log_level; |
1495cc9d | 527 | op_p->handler(key); |
bf36b901 | 528 | } else { |
1da177e4 | 529 | printk("This sysrq operation is disabled.\n"); |
bf36b901 | 530 | } |
1da177e4 LT |
531 | } else { |
532 | printk("HELP : "); | |
533 | /* Only print the help msg once per handler */ | |
bf36b901 AM |
534 | for (i = 0; i < ARRAY_SIZE(sysrq_key_table); i++) { |
535 | if (sysrq_key_table[i]) { | |
536 | int j; | |
537 | ||
538 | for (j = 0; sysrq_key_table[i] != | |
539 | sysrq_key_table[j]; j++) | |
540 | ; | |
541 | if (j != i) | |
542 | continue; | |
543 | printk("%s ", sysrq_key_table[i]->help_msg); | |
544 | } | |
1da177e4 | 545 | } |
bf36b901 | 546 | printk("\n"); |
1da177e4 LT |
547 | console_loglevel = orig_log_level; |
548 | } | |
549 | spin_unlock_irqrestore(&sysrq_key_table_lock, flags); | |
550 | } | |
551 | ||
f335397d | 552 | void handle_sysrq(int key) |
1da177e4 | 553 | { |
5d6f647f | 554 | if (sysrq_on()) |
f335397d | 555 | __handle_sysrq(key, true); |
1da177e4 | 556 | } |
bf36b901 | 557 | EXPORT_SYMBOL(handle_sysrq); |
1da177e4 | 558 | |
97f5f0cd DT |
559 | #ifdef CONFIG_INPUT |
560 | ||
561 | /* Simple translation table for the SysRq keys */ | |
fcb71930 | 562 | static const unsigned char sysrq_xlate[KEY_CNT] = |
97f5f0cd DT |
563 | "\000\0331234567890-=\177\t" /* 0x00 - 0x0f */ |
564 | "qwertyuiop[]\r\000as" /* 0x10 - 0x1f */ | |
565 | "dfghjkl;'`\000\\zxcv" /* 0x20 - 0x2f */ | |
566 | "bnm,./\000*\000 \000\201\202\203\204\205" /* 0x30 - 0x3f */ | |
567 | "\206\207\210\211\212\000\000789-456+1" /* 0x40 - 0x4f */ | |
568 | "230\177\000\000\213\214\000\000\000\000\000\000\000\000\000\000" /* 0x50 - 0x5f */ | |
569 | "\r\000/"; /* 0x60 - 0x6f */ | |
570 | ||
fcb71930 DT |
571 | struct sysrq_state { |
572 | struct input_handle handle; | |
573 | struct work_struct reinject_work; | |
574 | unsigned long key_down[BITS_TO_LONGS(KEY_CNT)]; | |
575 | unsigned int alt; | |
576 | unsigned int alt_use; | |
577 | bool active; | |
578 | bool need_reinject; | |
7ab7b5ad | 579 | bool reinjecting; |
fcb71930 DT |
580 | }; |
581 | ||
582 | static void sysrq_reinject_alt_sysrq(struct work_struct *work) | |
583 | { | |
584 | struct sysrq_state *sysrq = | |
585 | container_of(work, struct sysrq_state, reinject_work); | |
586 | struct input_handle *handle = &sysrq->handle; | |
587 | unsigned int alt_code = sysrq->alt_use; | |
588 | ||
589 | if (sysrq->need_reinject) { | |
7ab7b5ad DT |
590 | /* we do not want the assignment to be reordered */ |
591 | sysrq->reinjecting = true; | |
592 | mb(); | |
593 | ||
fcb71930 DT |
594 | /* Simulate press and release of Alt + SysRq */ |
595 | input_inject_event(handle, EV_KEY, alt_code, 1); | |
596 | input_inject_event(handle, EV_KEY, KEY_SYSRQ, 1); | |
597 | input_inject_event(handle, EV_SYN, SYN_REPORT, 1); | |
598 | ||
599 | input_inject_event(handle, EV_KEY, KEY_SYSRQ, 0); | |
600 | input_inject_event(handle, EV_KEY, alt_code, 0); | |
601 | input_inject_event(handle, EV_SYN, SYN_REPORT, 1); | |
7ab7b5ad DT |
602 | |
603 | mb(); | |
604 | sysrq->reinjecting = false; | |
fcb71930 DT |
605 | } |
606 | } | |
97f5f0cd | 607 | |
fcb71930 DT |
608 | static bool sysrq_filter(struct input_handle *handle, |
609 | unsigned int type, unsigned int code, int value) | |
97f5f0cd | 610 | { |
fcb71930 DT |
611 | struct sysrq_state *sysrq = handle->private; |
612 | bool was_active = sysrq->active; | |
1966cb22 DT |
613 | bool suppress; |
614 | ||
7ab7b5ad DT |
615 | /* |
616 | * Do not filter anything if we are in the process of re-injecting | |
617 | * Alt+SysRq combination. | |
618 | */ | |
619 | if (sysrq->reinjecting) | |
620 | return false; | |
621 | ||
fcb71930 | 622 | switch (type) { |
1966cb22 | 623 | |
fcb71930 DT |
624 | case EV_SYN: |
625 | suppress = false; | |
626 | break; | |
97f5f0cd | 627 | |
fcb71930 DT |
628 | case EV_KEY: |
629 | switch (code) { | |
97f5f0cd | 630 | |
fcb71930 DT |
631 | case KEY_LEFTALT: |
632 | case KEY_RIGHTALT: | |
633 | if (!value) { | |
634 | /* One of ALTs is being released */ | |
635 | if (sysrq->active && code == sysrq->alt_use) | |
636 | sysrq->active = false; | |
f5dec511 | 637 | |
fcb71930 DT |
638 | sysrq->alt = KEY_RESERVED; |
639 | ||
640 | } else if (value != 2) { | |
641 | sysrq->alt = code; | |
642 | sysrq->need_reinject = false; | |
643 | } | |
644 | break; | |
645 | ||
646 | case KEY_SYSRQ: | |
647 | if (value == 1 && sysrq->alt != KEY_RESERVED) { | |
648 | sysrq->active = true; | |
649 | sysrq->alt_use = sysrq->alt; | |
650 | /* | |
651 | * If nothing else will be pressed we'll need | |
7ab7b5ad | 652 | * to re-inject Alt-SysRq keysroke. |
fcb71930 DT |
653 | */ |
654 | sysrq->need_reinject = true; | |
655 | } | |
656 | ||
657 | /* | |
658 | * Pretend that sysrq was never pressed at all. This | |
659 | * is needed to properly handle KGDB which will try | |
660 | * to release all keys after exiting debugger. If we | |
661 | * do not clear key bit it KGDB will end up sending | |
662 | * release events for Alt and SysRq, potentially | |
663 | * triggering print screen function. | |
664 | */ | |
665 | if (sysrq->active) | |
666 | clear_bit(KEY_SYSRQ, handle->dev->key); | |
667 | ||
668 | break; | |
669 | ||
670 | default: | |
671 | if (sysrq->active && value && value != 2) { | |
672 | sysrq->need_reinject = false; | |
673 | __handle_sysrq(sysrq_xlate[code], true); | |
674 | } | |
675 | break; | |
f5dec511 | 676 | } |
97f5f0cd | 677 | |
fcb71930 DT |
678 | suppress = sysrq->active; |
679 | ||
680 | if (!sysrq->active) { | |
681 | /* | |
682 | * If we are not suppressing key presses keep track of | |
683 | * keyboard state so we can release keys that have been | |
684 | * pressed before entering SysRq mode. | |
685 | */ | |
686 | if (value) | |
687 | set_bit(code, sysrq->key_down); | |
688 | else | |
689 | clear_bit(code, sysrq->key_down); | |
690 | ||
691 | if (was_active) | |
692 | schedule_work(&sysrq->reinject_work); | |
693 | ||
694 | } else if (value == 0 && | |
695 | test_and_clear_bit(code, sysrq->key_down)) { | |
696 | /* | |
697 | * Pass on release events for keys that was pressed before | |
698 | * entering SysRq mode. | |
699 | */ | |
700 | suppress = false; | |
97f5f0cd DT |
701 | } |
702 | break; | |
703 | ||
704 | default: | |
fcb71930 | 705 | suppress = sysrq->active; |
97f5f0cd DT |
706 | break; |
707 | } | |
708 | ||
1966cb22 | 709 | return suppress; |
97f5f0cd DT |
710 | } |
711 | ||
712 | static int sysrq_connect(struct input_handler *handler, | |
713 | struct input_dev *dev, | |
714 | const struct input_device_id *id) | |
715 | { | |
fcb71930 | 716 | struct sysrq_state *sysrq; |
97f5f0cd DT |
717 | int error; |
718 | ||
fcb71930 DT |
719 | sysrq = kzalloc(sizeof(struct sysrq_state), GFP_KERNEL); |
720 | if (!sysrq) | |
97f5f0cd DT |
721 | return -ENOMEM; |
722 | ||
fcb71930 DT |
723 | INIT_WORK(&sysrq->reinject_work, sysrq_reinject_alt_sysrq); |
724 | ||
725 | sysrq->handle.dev = dev; | |
726 | sysrq->handle.handler = handler; | |
727 | sysrq->handle.name = "sysrq"; | |
728 | sysrq->handle.private = sysrq; | |
97f5f0cd | 729 | |
fcb71930 | 730 | error = input_register_handle(&sysrq->handle); |
97f5f0cd DT |
731 | if (error) { |
732 | pr_err("Failed to register input sysrq handler, error %d\n", | |
733 | error); | |
734 | goto err_free; | |
735 | } | |
736 | ||
fcb71930 | 737 | error = input_open_device(&sysrq->handle); |
97f5f0cd DT |
738 | if (error) { |
739 | pr_err("Failed to open input device, error %d\n", error); | |
740 | goto err_unregister; | |
741 | } | |
742 | ||
743 | return 0; | |
744 | ||
745 | err_unregister: | |
fcb71930 | 746 | input_unregister_handle(&sysrq->handle); |
97f5f0cd | 747 | err_free: |
fcb71930 | 748 | kfree(sysrq); |
97f5f0cd DT |
749 | return error; |
750 | } | |
751 | ||
752 | static void sysrq_disconnect(struct input_handle *handle) | |
753 | { | |
fcb71930 DT |
754 | struct sysrq_state *sysrq = handle->private; |
755 | ||
97f5f0cd | 756 | input_close_device(handle); |
fcb71930 | 757 | cancel_work_sync(&sysrq->reinject_work); |
97f5f0cd | 758 | input_unregister_handle(handle); |
fcb71930 | 759 | kfree(sysrq); |
97f5f0cd DT |
760 | } |
761 | ||
762 | /* | |
1966cb22 DT |
763 | * We are matching on KEY_LEFTALT instead of KEY_SYSRQ because not all |
764 | * keyboards have SysRq key predefined and so user may add it to keymap | |
97f5f0cd DT |
765 | * later, but we expect all such keyboards to have left alt. |
766 | */ | |
767 | static const struct input_device_id sysrq_ids[] = { | |
768 | { | |
769 | .flags = INPUT_DEVICE_ID_MATCH_EVBIT | | |
770 | INPUT_DEVICE_ID_MATCH_KEYBIT, | |
771 | .evbit = { BIT_MASK(EV_KEY) }, | |
772 | .keybit = { BIT_MASK(KEY_LEFTALT) }, | |
773 | }, | |
774 | { }, | |
775 | }; | |
776 | ||
777 | static struct input_handler sysrq_handler = { | |
778 | .filter = sysrq_filter, | |
779 | .connect = sysrq_connect, | |
780 | .disconnect = sysrq_disconnect, | |
781 | .name = "sysrq", | |
782 | .id_table = sysrq_ids, | |
783 | }; | |
784 | ||
785 | static bool sysrq_handler_registered; | |
786 | ||
787 | static inline void sysrq_register_handler(void) | |
788 | { | |
789 | int error; | |
790 | ||
791 | error = input_register_handler(&sysrq_handler); | |
792 | if (error) | |
793 | pr_err("Failed to register input handler, error %d", error); | |
794 | else | |
795 | sysrq_handler_registered = true; | |
796 | } | |
797 | ||
798 | static inline void sysrq_unregister_handler(void) | |
799 | { | |
800 | if (sysrq_handler_registered) { | |
801 | input_unregister_handler(&sysrq_handler); | |
802 | sysrq_handler_registered = false; | |
803 | } | |
804 | } | |
805 | ||
806 | #else | |
807 | ||
808 | static inline void sysrq_register_handler(void) | |
809 | { | |
810 | } | |
811 | ||
812 | static inline void sysrq_unregister_handler(void) | |
813 | { | |
814 | } | |
815 | ||
816 | #endif /* CONFIG_INPUT */ | |
817 | ||
818 | int sysrq_toggle_support(int enable_mask) | |
819 | { | |
820 | bool was_enabled = sysrq_on(); | |
821 | ||
822 | sysrq_enabled = enable_mask; | |
823 | ||
824 | if (was_enabled != sysrq_on()) { | |
825 | if (sysrq_on()) | |
826 | sysrq_register_handler(); | |
827 | else | |
828 | sysrq_unregister_handler(); | |
829 | } | |
830 | ||
831 | return 0; | |
832 | } | |
833 | ||
cf62ddce | 834 | static int __sysrq_swap_key_ops(int key, struct sysrq_key_op *insert_op_p, |
bf36b901 AM |
835 | struct sysrq_key_op *remove_op_p) |
836 | { | |
1da177e4 LT |
837 | int retval; |
838 | unsigned long flags; | |
839 | ||
840 | spin_lock_irqsave(&sysrq_key_table_lock, flags); | |
841 | if (__sysrq_get_key_op(key) == remove_op_p) { | |
842 | __sysrq_put_key_op(key, insert_op_p); | |
843 | retval = 0; | |
844 | } else { | |
845 | retval = -1; | |
846 | } | |
847 | spin_unlock_irqrestore(&sysrq_key_table_lock, flags); | |
1da177e4 LT |
848 | return retval; |
849 | } | |
850 | ||
851 | int register_sysrq_key(int key, struct sysrq_key_op *op_p) | |
852 | { | |
853 | return __sysrq_swap_key_ops(key, op_p, NULL); | |
854 | } | |
bf36b901 | 855 | EXPORT_SYMBOL(register_sysrq_key); |
1da177e4 LT |
856 | |
857 | int unregister_sysrq_key(int key, struct sysrq_key_op *op_p) | |
858 | { | |
859 | return __sysrq_swap_key_ops(key, NULL, op_p); | |
860 | } | |
1da177e4 | 861 | EXPORT_SYMBOL(unregister_sysrq_key); |
f40cbaa5 AD |
862 | |
863 | #ifdef CONFIG_PROC_FS | |
864 | /* | |
865 | * writing 'C' to /proc/sysrq-trigger is like sysrq-C | |
866 | */ | |
867 | static ssize_t write_sysrq_trigger(struct file *file, const char __user *buf, | |
868 | size_t count, loff_t *ppos) | |
869 | { | |
870 | if (count) { | |
871 | char c; | |
872 | ||
873 | if (get_user(c, buf)) | |
874 | return -EFAULT; | |
f335397d | 875 | __handle_sysrq(c, false); |
f40cbaa5 | 876 | } |
97f5f0cd | 877 | |
f40cbaa5 AD |
878 | return count; |
879 | } | |
880 | ||
881 | static const struct file_operations proc_sysrq_trigger_operations = { | |
882 | .write = write_sysrq_trigger, | |
6038f373 | 883 | .llseek = noop_llseek, |
f40cbaa5 AD |
884 | }; |
885 | ||
97f5f0cd DT |
886 | static void sysrq_init_procfs(void) |
887 | { | |
888 | if (!proc_create("sysrq-trigger", S_IWUSR, NULL, | |
889 | &proc_sysrq_trigger_operations)) | |
890 | pr_err("Failed to register proc interface\n"); | |
891 | } | |
892 | ||
893 | #else | |
894 | ||
895 | static inline void sysrq_init_procfs(void) | |
896 | { | |
897 | } | |
898 | ||
899 | #endif /* CONFIG_PROC_FS */ | |
900 | ||
f40cbaa5 AD |
901 | static int __init sysrq_init(void) |
902 | { | |
97f5f0cd DT |
903 | sysrq_init_procfs(); |
904 | ||
905 | if (sysrq_on()) | |
906 | sysrq_register_handler(); | |
907 | ||
f40cbaa5 AD |
908 | return 0; |
909 | } | |
910 | module_init(sysrq_init); |