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Commit | Line | Data |
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97f5f0cd | 1 | /* |
1da177e4 LT |
2 | * Linux Magic System Request Key Hacks |
3 | * | |
4 | * (c) 1997 Martin Mares <mj@atrey.karlin.mff.cuni.cz> | |
5 | * based on ideas by Pavel Machek <pavel@atrey.karlin.mff.cuni.cz> | |
6 | * | |
7 | * (c) 2000 Crutcher Dunnavant <crutcher+kernel@datastacks.com> | |
8 | * overhauled to use key registration | |
9 | * based upon discusions in irc://irc.openprojects.net/#kernelnewbies | |
97f5f0cd DT |
10 | * |
11 | * Copyright (c) 2010 Dmitry Torokhov | |
12 | * Input handler conversion | |
1da177e4 LT |
13 | */ |
14 | ||
97f5f0cd DT |
15 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
16 | ||
1da177e4 LT |
17 | #include <linux/sched.h> |
18 | #include <linux/interrupt.h> | |
19 | #include <linux/mm.h> | |
20 | #include <linux/fs.h> | |
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 */ | |
916ca14a | 455 | /* x: May be registered on sparc64 for global PMU dump */ |
d346cce3 | 456 | NULL, /* x */ |
93dae5b7 | 457 | /* y: May be registered on sparc64 for global register dump */ |
bf36b901 | 458 | NULL, /* y */ |
69f698ad | 459 | &sysrq_ftrace_dump_op, /* z */ |
1da177e4 LT |
460 | }; |
461 | ||
462 | /* key2index calculation, -1 on invalid index */ | |
bf36b901 AM |
463 | static int sysrq_key_table_key2index(int key) |
464 | { | |
1da177e4 | 465 | int retval; |
bf36b901 AM |
466 | |
467 | if ((key >= '0') && (key <= '9')) | |
1da177e4 | 468 | retval = key - '0'; |
bf36b901 | 469 | else if ((key >= 'a') && (key <= 'z')) |
1da177e4 | 470 | retval = key + 10 - 'a'; |
bf36b901 | 471 | else |
1da177e4 | 472 | retval = -1; |
1da177e4 LT |
473 | return retval; |
474 | } | |
475 | ||
476 | /* | |
477 | * get and put functions for the table, exposed to modules. | |
478 | */ | |
bf36b901 AM |
479 | struct sysrq_key_op *__sysrq_get_key_op(int key) |
480 | { | |
481 | struct sysrq_key_op *op_p = NULL; | |
1da177e4 | 482 | int i; |
bf36b901 | 483 | |
1da177e4 | 484 | i = sysrq_key_table_key2index(key); |
bf36b901 AM |
485 | if (i != -1) |
486 | op_p = sysrq_key_table[i]; | |
97f5f0cd | 487 | |
1da177e4 LT |
488 | return op_p; |
489 | } | |
490 | ||
bf36b901 AM |
491 | static void __sysrq_put_key_op(int key, struct sysrq_key_op *op_p) |
492 | { | |
493 | int i = sysrq_key_table_key2index(key); | |
1da177e4 | 494 | |
1da177e4 LT |
495 | if (i != -1) |
496 | sysrq_key_table[i] = op_p; | |
497 | } | |
498 | ||
f335397d | 499 | void __handle_sysrq(int key, bool check_mask) |
1da177e4 LT |
500 | { |
501 | struct sysrq_key_op *op_p; | |
502 | int orig_log_level; | |
bf36b901 | 503 | int i; |
1da177e4 LT |
504 | unsigned long flags; |
505 | ||
506 | spin_lock_irqsave(&sysrq_key_table_lock, flags); | |
fb144adc AW |
507 | /* |
508 | * Raise the apparent loglevel to maximum so that the sysrq header | |
509 | * is shown to provide the user with positive feedback. We do not | |
510 | * simply emit this at KERN_EMERG as that would change message | |
511 | * routing in the consumers of /proc/kmsg. | |
512 | */ | |
1da177e4 LT |
513 | orig_log_level = console_loglevel; |
514 | console_loglevel = 7; | |
515 | printk(KERN_INFO "SysRq : "); | |
516 | ||
517 | op_p = __sysrq_get_key_op(key); | |
518 | if (op_p) { | |
bf36b901 AM |
519 | /* |
520 | * Should we check for enabled operations (/proc/sysrq-trigger | |
521 | * should not) and is the invoked operation enabled? | |
522 | */ | |
5d6f647f | 523 | if (!check_mask || sysrq_on_mask(op_p->enable_mask)) { |
bf36b901 | 524 | printk("%s\n", op_p->action_msg); |
1da177e4 | 525 | console_loglevel = orig_log_level; |
1495cc9d | 526 | op_p->handler(key); |
bf36b901 | 527 | } else { |
1da177e4 | 528 | printk("This sysrq operation is disabled.\n"); |
bf36b901 | 529 | } |
1da177e4 LT |
530 | } else { |
531 | printk("HELP : "); | |
532 | /* Only print the help msg once per handler */ | |
bf36b901 AM |
533 | for (i = 0; i < ARRAY_SIZE(sysrq_key_table); i++) { |
534 | if (sysrq_key_table[i]) { | |
535 | int j; | |
536 | ||
537 | for (j = 0; sysrq_key_table[i] != | |
538 | sysrq_key_table[j]; j++) | |
539 | ; | |
540 | if (j != i) | |
541 | continue; | |
542 | printk("%s ", sysrq_key_table[i]->help_msg); | |
543 | } | |
1da177e4 | 544 | } |
bf36b901 | 545 | printk("\n"); |
1da177e4 LT |
546 | console_loglevel = orig_log_level; |
547 | } | |
548 | spin_unlock_irqrestore(&sysrq_key_table_lock, flags); | |
549 | } | |
550 | ||
f335397d | 551 | void handle_sysrq(int key) |
1da177e4 | 552 | { |
5d6f647f | 553 | if (sysrq_on()) |
f335397d | 554 | __handle_sysrq(key, true); |
1da177e4 | 555 | } |
bf36b901 | 556 | EXPORT_SYMBOL(handle_sysrq); |
1da177e4 | 557 | |
97f5f0cd DT |
558 | #ifdef CONFIG_INPUT |
559 | ||
560 | /* Simple translation table for the SysRq keys */ | |
fcb71930 | 561 | static const unsigned char sysrq_xlate[KEY_CNT] = |
97f5f0cd DT |
562 | "\000\0331234567890-=\177\t" /* 0x00 - 0x0f */ |
563 | "qwertyuiop[]\r\000as" /* 0x10 - 0x1f */ | |
564 | "dfghjkl;'`\000\\zxcv" /* 0x20 - 0x2f */ | |
565 | "bnm,./\000*\000 \000\201\202\203\204\205" /* 0x30 - 0x3f */ | |
566 | "\206\207\210\211\212\000\000789-456+1" /* 0x40 - 0x4f */ | |
567 | "230\177\000\000\213\214\000\000\000\000\000\000\000\000\000\000" /* 0x50 - 0x5f */ | |
568 | "\r\000/"; /* 0x60 - 0x6f */ | |
569 | ||
fcb71930 DT |
570 | struct sysrq_state { |
571 | struct input_handle handle; | |
572 | struct work_struct reinject_work; | |
573 | unsigned long key_down[BITS_TO_LONGS(KEY_CNT)]; | |
574 | unsigned int alt; | |
575 | unsigned int alt_use; | |
576 | bool active; | |
577 | bool need_reinject; | |
7ab7b5ad | 578 | bool reinjecting; |
fcb71930 DT |
579 | }; |
580 | ||
581 | static void sysrq_reinject_alt_sysrq(struct work_struct *work) | |
582 | { | |
583 | struct sysrq_state *sysrq = | |
584 | container_of(work, struct sysrq_state, reinject_work); | |
585 | struct input_handle *handle = &sysrq->handle; | |
586 | unsigned int alt_code = sysrq->alt_use; | |
587 | ||
588 | if (sysrq->need_reinject) { | |
7ab7b5ad DT |
589 | /* we do not want the assignment to be reordered */ |
590 | sysrq->reinjecting = true; | |
591 | mb(); | |
592 | ||
fcb71930 DT |
593 | /* Simulate press and release of Alt + SysRq */ |
594 | input_inject_event(handle, EV_KEY, alt_code, 1); | |
595 | input_inject_event(handle, EV_KEY, KEY_SYSRQ, 1); | |
596 | input_inject_event(handle, EV_SYN, SYN_REPORT, 1); | |
597 | ||
598 | input_inject_event(handle, EV_KEY, KEY_SYSRQ, 0); | |
599 | input_inject_event(handle, EV_KEY, alt_code, 0); | |
600 | input_inject_event(handle, EV_SYN, SYN_REPORT, 1); | |
7ab7b5ad DT |
601 | |
602 | mb(); | |
603 | sysrq->reinjecting = false; | |
fcb71930 DT |
604 | } |
605 | } | |
97f5f0cd | 606 | |
fcb71930 DT |
607 | static bool sysrq_filter(struct input_handle *handle, |
608 | unsigned int type, unsigned int code, int value) | |
97f5f0cd | 609 | { |
fcb71930 DT |
610 | struct sysrq_state *sysrq = handle->private; |
611 | bool was_active = sysrq->active; | |
1966cb22 DT |
612 | bool suppress; |
613 | ||
7ab7b5ad DT |
614 | /* |
615 | * Do not filter anything if we are in the process of re-injecting | |
616 | * Alt+SysRq combination. | |
617 | */ | |
618 | if (sysrq->reinjecting) | |
619 | return false; | |
620 | ||
fcb71930 | 621 | switch (type) { |
1966cb22 | 622 | |
fcb71930 DT |
623 | case EV_SYN: |
624 | suppress = false; | |
625 | break; | |
97f5f0cd | 626 | |
fcb71930 DT |
627 | case EV_KEY: |
628 | switch (code) { | |
97f5f0cd | 629 | |
fcb71930 DT |
630 | case KEY_LEFTALT: |
631 | case KEY_RIGHTALT: | |
632 | if (!value) { | |
633 | /* One of ALTs is being released */ | |
634 | if (sysrq->active && code == sysrq->alt_use) | |
635 | sysrq->active = false; | |
f5dec511 | 636 | |
fcb71930 DT |
637 | sysrq->alt = KEY_RESERVED; |
638 | ||
639 | } else if (value != 2) { | |
640 | sysrq->alt = code; | |
641 | sysrq->need_reinject = false; | |
642 | } | |
643 | break; | |
644 | ||
645 | case KEY_SYSRQ: | |
646 | if (value == 1 && sysrq->alt != KEY_RESERVED) { | |
647 | sysrq->active = true; | |
648 | sysrq->alt_use = sysrq->alt; | |
649 | /* | |
650 | * If nothing else will be pressed we'll need | |
7ab7b5ad | 651 | * to re-inject Alt-SysRq keysroke. |
fcb71930 DT |
652 | */ |
653 | sysrq->need_reinject = true; | |
654 | } | |
655 | ||
656 | /* | |
657 | * Pretend that sysrq was never pressed at all. This | |
658 | * is needed to properly handle KGDB which will try | |
659 | * to release all keys after exiting debugger. If we | |
660 | * do not clear key bit it KGDB will end up sending | |
661 | * release events for Alt and SysRq, potentially | |
662 | * triggering print screen function. | |
663 | */ | |
664 | if (sysrq->active) | |
665 | clear_bit(KEY_SYSRQ, handle->dev->key); | |
666 | ||
667 | break; | |
668 | ||
669 | default: | |
670 | if (sysrq->active && value && value != 2) { | |
671 | sysrq->need_reinject = false; | |
672 | __handle_sysrq(sysrq_xlate[code], true); | |
673 | } | |
674 | break; | |
f5dec511 | 675 | } |
97f5f0cd | 676 | |
fcb71930 DT |
677 | suppress = sysrq->active; |
678 | ||
679 | if (!sysrq->active) { | |
680 | /* | |
681 | * If we are not suppressing key presses keep track of | |
682 | * keyboard state so we can release keys that have been | |
683 | * pressed before entering SysRq mode. | |
684 | */ | |
685 | if (value) | |
686 | set_bit(code, sysrq->key_down); | |
687 | else | |
688 | clear_bit(code, sysrq->key_down); | |
689 | ||
690 | if (was_active) | |
691 | schedule_work(&sysrq->reinject_work); | |
692 | ||
693 | } else if (value == 0 && | |
694 | test_and_clear_bit(code, sysrq->key_down)) { | |
695 | /* | |
696 | * Pass on release events for keys that was pressed before | |
697 | * entering SysRq mode. | |
698 | */ | |
699 | suppress = false; | |
97f5f0cd DT |
700 | } |
701 | break; | |
702 | ||
703 | default: | |
fcb71930 | 704 | suppress = sysrq->active; |
97f5f0cd DT |
705 | break; |
706 | } | |
707 | ||
1966cb22 | 708 | return suppress; |
97f5f0cd DT |
709 | } |
710 | ||
711 | static int sysrq_connect(struct input_handler *handler, | |
712 | struct input_dev *dev, | |
713 | const struct input_device_id *id) | |
714 | { | |
fcb71930 | 715 | struct sysrq_state *sysrq; |
97f5f0cd DT |
716 | int error; |
717 | ||
fcb71930 DT |
718 | sysrq = kzalloc(sizeof(struct sysrq_state), GFP_KERNEL); |
719 | if (!sysrq) | |
97f5f0cd DT |
720 | return -ENOMEM; |
721 | ||
fcb71930 DT |
722 | INIT_WORK(&sysrq->reinject_work, sysrq_reinject_alt_sysrq); |
723 | ||
724 | sysrq->handle.dev = dev; | |
725 | sysrq->handle.handler = handler; | |
726 | sysrq->handle.name = "sysrq"; | |
727 | sysrq->handle.private = sysrq; | |
97f5f0cd | 728 | |
fcb71930 | 729 | error = input_register_handle(&sysrq->handle); |
97f5f0cd DT |
730 | if (error) { |
731 | pr_err("Failed to register input sysrq handler, error %d\n", | |
732 | error); | |
733 | goto err_free; | |
734 | } | |
735 | ||
fcb71930 | 736 | error = input_open_device(&sysrq->handle); |
97f5f0cd DT |
737 | if (error) { |
738 | pr_err("Failed to open input device, error %d\n", error); | |
739 | goto err_unregister; | |
740 | } | |
741 | ||
742 | return 0; | |
743 | ||
744 | err_unregister: | |
fcb71930 | 745 | input_unregister_handle(&sysrq->handle); |
97f5f0cd | 746 | err_free: |
fcb71930 | 747 | kfree(sysrq); |
97f5f0cd DT |
748 | return error; |
749 | } | |
750 | ||
751 | static void sysrq_disconnect(struct input_handle *handle) | |
752 | { | |
fcb71930 DT |
753 | struct sysrq_state *sysrq = handle->private; |
754 | ||
97f5f0cd | 755 | input_close_device(handle); |
fcb71930 | 756 | cancel_work_sync(&sysrq->reinject_work); |
97f5f0cd | 757 | input_unregister_handle(handle); |
fcb71930 | 758 | kfree(sysrq); |
97f5f0cd DT |
759 | } |
760 | ||
761 | /* | |
1966cb22 DT |
762 | * We are matching on KEY_LEFTALT instead of KEY_SYSRQ because not all |
763 | * keyboards have SysRq key predefined and so user may add it to keymap | |
97f5f0cd DT |
764 | * later, but we expect all such keyboards to have left alt. |
765 | */ | |
766 | static const struct input_device_id sysrq_ids[] = { | |
767 | { | |
768 | .flags = INPUT_DEVICE_ID_MATCH_EVBIT | | |
769 | INPUT_DEVICE_ID_MATCH_KEYBIT, | |
770 | .evbit = { BIT_MASK(EV_KEY) }, | |
771 | .keybit = { BIT_MASK(KEY_LEFTALT) }, | |
772 | }, | |
773 | { }, | |
774 | }; | |
775 | ||
776 | static struct input_handler sysrq_handler = { | |
777 | .filter = sysrq_filter, | |
778 | .connect = sysrq_connect, | |
779 | .disconnect = sysrq_disconnect, | |
780 | .name = "sysrq", | |
781 | .id_table = sysrq_ids, | |
782 | }; | |
783 | ||
784 | static bool sysrq_handler_registered; | |
785 | ||
786 | static inline void sysrq_register_handler(void) | |
787 | { | |
788 | int error; | |
789 | ||
790 | error = input_register_handler(&sysrq_handler); | |
791 | if (error) | |
792 | pr_err("Failed to register input handler, error %d", error); | |
793 | else | |
794 | sysrq_handler_registered = true; | |
795 | } | |
796 | ||
797 | static inline void sysrq_unregister_handler(void) | |
798 | { | |
799 | if (sysrq_handler_registered) { | |
800 | input_unregister_handler(&sysrq_handler); | |
801 | sysrq_handler_registered = false; | |
802 | } | |
803 | } | |
804 | ||
805 | #else | |
806 | ||
807 | static inline void sysrq_register_handler(void) | |
808 | { | |
809 | } | |
810 | ||
811 | static inline void sysrq_unregister_handler(void) | |
812 | { | |
813 | } | |
814 | ||
815 | #endif /* CONFIG_INPUT */ | |
816 | ||
817 | int sysrq_toggle_support(int enable_mask) | |
818 | { | |
819 | bool was_enabled = sysrq_on(); | |
820 | ||
821 | sysrq_enabled = enable_mask; | |
822 | ||
823 | if (was_enabled != sysrq_on()) { | |
824 | if (sysrq_on()) | |
825 | sysrq_register_handler(); | |
826 | else | |
827 | sysrq_unregister_handler(); | |
828 | } | |
829 | ||
830 | return 0; | |
831 | } | |
832 | ||
cf62ddce | 833 | static int __sysrq_swap_key_ops(int key, struct sysrq_key_op *insert_op_p, |
bf36b901 AM |
834 | struct sysrq_key_op *remove_op_p) |
835 | { | |
1da177e4 LT |
836 | int retval; |
837 | unsigned long flags; | |
838 | ||
839 | spin_lock_irqsave(&sysrq_key_table_lock, flags); | |
840 | if (__sysrq_get_key_op(key) == remove_op_p) { | |
841 | __sysrq_put_key_op(key, insert_op_p); | |
842 | retval = 0; | |
843 | } else { | |
844 | retval = -1; | |
845 | } | |
846 | spin_unlock_irqrestore(&sysrq_key_table_lock, flags); | |
1da177e4 LT |
847 | return retval; |
848 | } | |
849 | ||
850 | int register_sysrq_key(int key, struct sysrq_key_op *op_p) | |
851 | { | |
852 | return __sysrq_swap_key_ops(key, op_p, NULL); | |
853 | } | |
bf36b901 | 854 | EXPORT_SYMBOL(register_sysrq_key); |
1da177e4 LT |
855 | |
856 | int unregister_sysrq_key(int key, struct sysrq_key_op *op_p) | |
857 | { | |
858 | return __sysrq_swap_key_ops(key, NULL, op_p); | |
859 | } | |
1da177e4 | 860 | EXPORT_SYMBOL(unregister_sysrq_key); |
f40cbaa5 AD |
861 | |
862 | #ifdef CONFIG_PROC_FS | |
863 | /* | |
864 | * writing 'C' to /proc/sysrq-trigger is like sysrq-C | |
865 | */ | |
866 | static ssize_t write_sysrq_trigger(struct file *file, const char __user *buf, | |
867 | size_t count, loff_t *ppos) | |
868 | { | |
869 | if (count) { | |
870 | char c; | |
871 | ||
872 | if (get_user(c, buf)) | |
873 | return -EFAULT; | |
f335397d | 874 | __handle_sysrq(c, false); |
f40cbaa5 | 875 | } |
97f5f0cd | 876 | |
f40cbaa5 AD |
877 | return count; |
878 | } | |
879 | ||
880 | static const struct file_operations proc_sysrq_trigger_operations = { | |
881 | .write = write_sysrq_trigger, | |
6038f373 | 882 | .llseek = noop_llseek, |
f40cbaa5 AD |
883 | }; |
884 | ||
97f5f0cd DT |
885 | static void sysrq_init_procfs(void) |
886 | { | |
887 | if (!proc_create("sysrq-trigger", S_IWUSR, NULL, | |
888 | &proc_sysrq_trigger_operations)) | |
889 | pr_err("Failed to register proc interface\n"); | |
890 | } | |
891 | ||
892 | #else | |
893 | ||
894 | static inline void sysrq_init_procfs(void) | |
895 | { | |
896 | } | |
897 | ||
898 | #endif /* CONFIG_PROC_FS */ | |
899 | ||
f40cbaa5 AD |
900 | static int __init sysrq_init(void) |
901 | { | |
97f5f0cd DT |
902 | sysrq_init_procfs(); |
903 | ||
904 | if (sysrq_on()) | |
905 | sysrq_register_handler(); | |
906 | ||
f40cbaa5 AD |
907 | return 0; |
908 | } | |
909 | module_init(sysrq_init); |