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 | 17 | #include <linux/sched.h> |
8bd75c77 | 18 | #include <linux/sched/rt.h> |
1da177e4 LT |
19 | #include <linux/interrupt.h> |
20 | #include <linux/mm.h> | |
21 | #include <linux/fs.h> | |
1da177e4 LT |
22 | #include <linux/mount.h> |
23 | #include <linux/kdev_t.h> | |
24 | #include <linux/major.h> | |
25 | #include <linux/reboot.h> | |
26 | #include <linux/sysrq.h> | |
27 | #include <linux/kbd_kern.h> | |
f40cbaa5 | 28 | #include <linux/proc_fs.h> |
c1dc0b9c | 29 | #include <linux/nmi.h> |
1da177e4 | 30 | #include <linux/quotaops.h> |
cdd6c482 | 31 | #include <linux/perf_event.h> |
1da177e4 LT |
32 | #include <linux/kernel.h> |
33 | #include <linux/module.h> | |
34 | #include <linux/suspend.h> | |
35 | #include <linux/writeback.h> | |
1da177e4 LT |
36 | #include <linux/swap.h> |
37 | #include <linux/spinlock.h> | |
38 | #include <linux/vt_kern.h> | |
39 | #include <linux/workqueue.h> | |
88ad0bf6 | 40 | #include <linux/hrtimer.h> |
5a3135c2 | 41 | #include <linux/oom.h> |
5a0e3ad6 | 42 | #include <linux/slab.h> |
97f5f0cd | 43 | #include <linux/input.h> |
ff01bb48 | 44 | #include <linux/uaccess.h> |
154b7a48 | 45 | #include <linux/moduleparam.h> |
39030786 | 46 | #include <linux/jiffies.h> |
3d289517 | 47 | #include <linux/syscalls.h> |
4c076eb0 | 48 | #include <linux/of.h> |
722773af | 49 | #include <linux/rcupdate.h> |
1da177e4 LT |
50 | |
51 | #include <asm/ptrace.h> | |
2033b0c3 | 52 | #include <asm/irq_regs.h> |
1da177e4 LT |
53 | |
54 | /* Whether we react on sysrq keys or just ignore them */ | |
8eaede49 | 55 | static int __read_mostly sysrq_enabled = CONFIG_MAGIC_SYSRQ_DEFAULT_ENABLE; |
97f5f0cd | 56 | static bool __read_mostly sysrq_always_enabled; |
5d6f647f | 57 | |
97f5f0cd | 58 | static bool sysrq_on(void) |
5d6f647f | 59 | { |
97f5f0cd | 60 | return sysrq_enabled || sysrq_always_enabled; |
5d6f647f IM |
61 | } |
62 | ||
63 | /* | |
64 | * A value of 1 means 'all', other nonzero values are an op mask: | |
65 | */ | |
97f5f0cd | 66 | static bool sysrq_on_mask(int mask) |
5d6f647f | 67 | { |
97f5f0cd DT |
68 | return sysrq_always_enabled || |
69 | sysrq_enabled == 1 || | |
70 | (sysrq_enabled & mask); | |
5d6f647f IM |
71 | } |
72 | ||
73 | static int __init sysrq_always_enabled_setup(char *str) | |
74 | { | |
97f5f0cd DT |
75 | sysrq_always_enabled = true; |
76 | pr_info("sysrq always enabled.\n"); | |
5d6f647f IM |
77 | |
78 | return 1; | |
79 | } | |
80 | ||
81 | __setup("sysrq_always_enabled", sysrq_always_enabled_setup); | |
82 | ||
1da177e4 | 83 | |
1495cc9d | 84 | static void sysrq_handle_loglevel(int key) |
1da177e4 LT |
85 | { |
86 | int i; | |
97f5f0cd | 87 | |
1da177e4 | 88 | i = key - '0'; |
a8fe19eb | 89 | console_loglevel = CONSOLE_LOGLEVEL_DEFAULT; |
401e4a7c | 90 | pr_info("Loglevel set to %d\n", i); |
1da177e4 | 91 | console_loglevel = i; |
bf36b901 | 92 | } |
1da177e4 LT |
93 | static struct sysrq_key_op sysrq_loglevel_op = { |
94 | .handler = sysrq_handle_loglevel, | |
208b95ce | 95 | .help_msg = "loglevel(0-9)", |
1da177e4 LT |
96 | .action_msg = "Changing Loglevel", |
97 | .enable_mask = SYSRQ_ENABLE_LOG, | |
98 | }; | |
99 | ||
1da177e4 | 100 | #ifdef CONFIG_VT |
1495cc9d | 101 | static void sysrq_handle_SAK(int key) |
1da177e4 | 102 | { |
8b6312f4 | 103 | struct work_struct *SAK_work = &vc_cons[fg_console].SAK_work; |
8b6312f4 | 104 | schedule_work(SAK_work); |
1da177e4 LT |
105 | } |
106 | static struct sysrq_key_op sysrq_SAK_op = { | |
107 | .handler = sysrq_handle_SAK, | |
afa80ccb | 108 | .help_msg = "sak(k)", |
1da177e4 LT |
109 | .action_msg = "SAK", |
110 | .enable_mask = SYSRQ_ENABLE_KEYBOARD, | |
111 | }; | |
bf36b901 | 112 | #else |
97f5f0cd | 113 | #define sysrq_SAK_op (*(struct sysrq_key_op *)NULL) |
1da177e4 LT |
114 | #endif |
115 | ||
116 | #ifdef CONFIG_VT | |
1495cc9d | 117 | static void sysrq_handle_unraw(int key) |
1da177e4 | 118 | { |
079c9534 | 119 | vt_reset_unicode(fg_console); |
1da177e4 | 120 | } |
079c9534 | 121 | |
1da177e4 LT |
122 | static struct sysrq_key_op sysrq_unraw_op = { |
123 | .handler = sysrq_handle_unraw, | |
afa80ccb | 124 | .help_msg = "unraw(r)", |
2e8ecb9d | 125 | .action_msg = "Keyboard mode set to system default", |
1da177e4 LT |
126 | .enable_mask = SYSRQ_ENABLE_KEYBOARD, |
127 | }; | |
bf36b901 | 128 | #else |
97f5f0cd | 129 | #define sysrq_unraw_op (*(struct sysrq_key_op *)NULL) |
1da177e4 LT |
130 | #endif /* CONFIG_VT */ |
131 | ||
1495cc9d | 132 | static void sysrq_handle_crash(int key) |
86b1ae38 | 133 | { |
d6580a9f | 134 | char *killer = NULL; |
cab8bd34 HS |
135 | |
136 | panic_on_oops = 1; /* force panic */ | |
137 | wmb(); | |
d6580a9f | 138 | *killer = 1; |
86b1ae38 | 139 | } |
cab8bd34 | 140 | static struct sysrq_key_op sysrq_crash_op = { |
d6580a9f | 141 | .handler = sysrq_handle_crash, |
afa80ccb | 142 | .help_msg = "crash(c)", |
d6580a9f | 143 | .action_msg = "Trigger a crash", |
86b1ae38 HN |
144 | .enable_mask = SYSRQ_ENABLE_DUMP, |
145 | }; | |
86b1ae38 | 146 | |
1495cc9d | 147 | static void sysrq_handle_reboot(int key) |
1da177e4 | 148 | { |
b2e9c7d0 | 149 | lockdep_off(); |
1da177e4 | 150 | local_irq_enable(); |
4de8b9b7 | 151 | emergency_restart(); |
1da177e4 | 152 | } |
1da177e4 LT |
153 | static struct sysrq_key_op sysrq_reboot_op = { |
154 | .handler = sysrq_handle_reboot, | |
afa80ccb | 155 | .help_msg = "reboot(b)", |
1da177e4 LT |
156 | .action_msg = "Resetting", |
157 | .enable_mask = SYSRQ_ENABLE_BOOT, | |
158 | }; | |
159 | ||
1495cc9d | 160 | static void sysrq_handle_sync(int key) |
1da177e4 LT |
161 | { |
162 | emergency_sync(); | |
163 | } | |
1da177e4 LT |
164 | static struct sysrq_key_op sysrq_sync_op = { |
165 | .handler = sysrq_handle_sync, | |
afa80ccb | 166 | .help_msg = "sync(s)", |
1da177e4 LT |
167 | .action_msg = "Emergency Sync", |
168 | .enable_mask = SYSRQ_ENABLE_SYNC, | |
169 | }; | |
170 | ||
1495cc9d | 171 | static void sysrq_handle_show_timers(int key) |
88ad0bf6 IM |
172 | { |
173 | sysrq_timer_list_show(); | |
174 | } | |
175 | ||
176 | static struct sysrq_key_op sysrq_show_timers_op = { | |
177 | .handler = sysrq_handle_show_timers, | |
afa80ccb | 178 | .help_msg = "show-all-timers(q)", |
322acf65 | 179 | .action_msg = "Show clockevent devices & pending hrtimers (no others)", |
88ad0bf6 IM |
180 | }; |
181 | ||
1495cc9d | 182 | static void sysrq_handle_mountro(int key) |
1da177e4 LT |
183 | { |
184 | emergency_remount(); | |
185 | } | |
1da177e4 LT |
186 | static struct sysrq_key_op sysrq_mountro_op = { |
187 | .handler = sysrq_handle_mountro, | |
afa80ccb | 188 | .help_msg = "unmount(u)", |
1da177e4 LT |
189 | .action_msg = "Emergency Remount R/O", |
190 | .enable_mask = SYSRQ_ENABLE_REMOUNT, | |
191 | }; | |
192 | ||
8c64580d | 193 | #ifdef CONFIG_LOCKDEP |
1495cc9d | 194 | static void sysrq_handle_showlocks(int key) |
de5097c2 | 195 | { |
9a11b49a | 196 | debug_show_all_locks(); |
de5097c2 | 197 | } |
8c64580d | 198 | |
de5097c2 IM |
199 | static struct sysrq_key_op sysrq_showlocks_op = { |
200 | .handler = sysrq_handle_showlocks, | |
afa80ccb | 201 | .help_msg = "show-all-locks(d)", |
de5097c2 IM |
202 | .action_msg = "Show Locks Held", |
203 | }; | |
bf36b901 | 204 | #else |
97f5f0cd | 205 | #define sysrq_showlocks_op (*(struct sysrq_key_op *)NULL) |
de5097c2 | 206 | #endif |
1da177e4 | 207 | |
5045bcae RR |
208 | #ifdef CONFIG_SMP |
209 | static DEFINE_SPINLOCK(show_lock); | |
210 | ||
211 | static void showacpu(void *dummy) | |
212 | { | |
213 | unsigned long flags; | |
214 | ||
215 | /* Idle CPUs have no interesting backtrace. */ | |
216 | if (idle_cpu(smp_processor_id())) | |
217 | return; | |
218 | ||
219 | spin_lock_irqsave(&show_lock, flags); | |
401e4a7c | 220 | pr_info("CPU%d:\n", smp_processor_id()); |
5045bcae RR |
221 | show_stack(NULL, NULL); |
222 | spin_unlock_irqrestore(&show_lock, flags); | |
223 | } | |
224 | ||
225 | static void sysrq_showregs_othercpus(struct work_struct *dummy) | |
226 | { | |
8b604d52 | 227 | smp_call_function(showacpu, NULL, 0); |
5045bcae RR |
228 | } |
229 | ||
230 | static DECLARE_WORK(sysrq_showallcpus, sysrq_showregs_othercpus); | |
231 | ||
1495cc9d | 232 | static void sysrq_handle_showallcpus(int key) |
5045bcae | 233 | { |
47cab6a7 IM |
234 | /* |
235 | * Fall back to the workqueue based printing if the | |
236 | * backtrace printing did not succeed or the | |
237 | * architecture has no support for it: | |
238 | */ | |
239 | if (!trigger_all_cpu_backtrace()) { | |
240 | struct pt_regs *regs = get_irq_regs(); | |
241 | ||
242 | if (regs) { | |
401e4a7c | 243 | pr_info("CPU%d:\n", smp_processor_id()); |
47cab6a7 IM |
244 | show_regs(regs); |
245 | } | |
246 | schedule_work(&sysrq_showallcpus); | |
247 | } | |
5045bcae RR |
248 | } |
249 | ||
250 | static struct sysrq_key_op sysrq_showallcpus_op = { | |
251 | .handler = sysrq_handle_showallcpus, | |
afa80ccb | 252 | .help_msg = "show-backtrace-all-active-cpus(l)", |
5045bcae RR |
253 | .action_msg = "Show backtrace of all active CPUs", |
254 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
255 | }; | |
256 | #endif | |
257 | ||
1495cc9d | 258 | static void sysrq_handle_showregs(int key) |
1da177e4 | 259 | { |
7d12e780 DH |
260 | struct pt_regs *regs = get_irq_regs(); |
261 | if (regs) | |
262 | show_regs(regs); | |
cdd6c482 | 263 | perf_event_print_debug(); |
1da177e4 LT |
264 | } |
265 | static struct sysrq_key_op sysrq_showregs_op = { | |
266 | .handler = sysrq_handle_showregs, | |
afa80ccb | 267 | .help_msg = "show-registers(p)", |
1da177e4 LT |
268 | .action_msg = "Show Regs", |
269 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
270 | }; | |
271 | ||
1495cc9d | 272 | static void sysrq_handle_showstate(int key) |
1da177e4 LT |
273 | { |
274 | show_state(); | |
3494fc30 | 275 | show_workqueue_state(); |
1da177e4 LT |
276 | } |
277 | static struct sysrq_key_op sysrq_showstate_op = { | |
278 | .handler = sysrq_handle_showstate, | |
afa80ccb | 279 | .help_msg = "show-task-states(t)", |
1da177e4 LT |
280 | .action_msg = "Show State", |
281 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
282 | }; | |
283 | ||
1495cc9d | 284 | static void sysrq_handle_showstate_blocked(int key) |
e59e2ae2 IM |
285 | { |
286 | show_state_filter(TASK_UNINTERRUPTIBLE); | |
287 | } | |
288 | static struct sysrq_key_op sysrq_showstate_blocked_op = { | |
289 | .handler = sysrq_handle_showstate_blocked, | |
afa80ccb | 290 | .help_msg = "show-blocked-tasks(w)", |
e59e2ae2 IM |
291 | .action_msg = "Show Blocked State", |
292 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
293 | }; | |
294 | ||
69f698ad PZ |
295 | #ifdef CONFIG_TRACING |
296 | #include <linux/ftrace.h> | |
297 | ||
1495cc9d | 298 | static void sysrq_ftrace_dump(int key) |
69f698ad | 299 | { |
cecbca96 | 300 | ftrace_dump(DUMP_ALL); |
69f698ad PZ |
301 | } |
302 | static struct sysrq_key_op sysrq_ftrace_dump_op = { | |
303 | .handler = sysrq_ftrace_dump, | |
afa80ccb | 304 | .help_msg = "dump-ftrace-buffer(z)", |
69f698ad PZ |
305 | .action_msg = "Dump ftrace buffer", |
306 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
307 | }; | |
308 | #else | |
97f5f0cd | 309 | #define sysrq_ftrace_dump_op (*(struct sysrq_key_op *)NULL) |
69f698ad | 310 | #endif |
e59e2ae2 | 311 | |
1495cc9d | 312 | static void sysrq_handle_showmem(int key) |
1da177e4 | 313 | { |
b2b755b5 | 314 | show_mem(0); |
1da177e4 LT |
315 | } |
316 | static struct sysrq_key_op sysrq_showmem_op = { | |
317 | .handler = sysrq_handle_showmem, | |
afa80ccb | 318 | .help_msg = "show-memory-usage(m)", |
1da177e4 LT |
319 | .action_msg = "Show Memory", |
320 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
321 | }; | |
322 | ||
bf36b901 AM |
323 | /* |
324 | * Signal sysrq helper function. Sends a signal to all user processes. | |
325 | */ | |
1da177e4 LT |
326 | static void send_sig_all(int sig) |
327 | { | |
328 | struct task_struct *p; | |
329 | ||
e502babe | 330 | read_lock(&tasklist_lock); |
1da177e4 | 331 | for_each_process(p) { |
d3a532a9 AV |
332 | if (p->flags & PF_KTHREAD) |
333 | continue; | |
334 | if (is_global_init(p)) | |
335 | continue; | |
336 | ||
b82c3287 | 337 | do_send_sig_info(sig, SEND_SIG_FORCED, p, true); |
1da177e4 | 338 | } |
e502babe | 339 | read_unlock(&tasklist_lock); |
1da177e4 LT |
340 | } |
341 | ||
1495cc9d | 342 | static void sysrq_handle_term(int key) |
1da177e4 LT |
343 | { |
344 | send_sig_all(SIGTERM); | |
a8fe19eb | 345 | console_loglevel = CONSOLE_LOGLEVEL_DEBUG; |
1da177e4 LT |
346 | } |
347 | static struct sysrq_key_op sysrq_term_op = { | |
348 | .handler = sysrq_handle_term, | |
afa80ccb | 349 | .help_msg = "terminate-all-tasks(e)", |
1da177e4 LT |
350 | .action_msg = "Terminate All Tasks", |
351 | .enable_mask = SYSRQ_ENABLE_SIGNAL, | |
352 | }; | |
353 | ||
65f27f38 | 354 | static void moom_callback(struct work_struct *ignored) |
1da177e4 | 355 | { |
6e0fc46d DR |
356 | const gfp_t gfp_mask = GFP_KERNEL; |
357 | struct oom_control oc = { | |
358 | .zonelist = node_zonelist(first_memory_node, gfp_mask), | |
359 | .nodemask = NULL, | |
360 | .gfp_mask = gfp_mask, | |
54e9e291 | 361 | .order = -1, |
6e0fc46d DR |
362 | }; |
363 | ||
dc56401f | 364 | mutex_lock(&oom_lock); |
6e0fc46d | 365 | if (!out_of_memory(&oc)) |
c32b3cbe | 366 | pr_info("OOM request ignored because killer is disabled\n"); |
dc56401f | 367 | mutex_unlock(&oom_lock); |
1da177e4 LT |
368 | } |
369 | ||
65f27f38 | 370 | static DECLARE_WORK(moom_work, moom_callback); |
1da177e4 | 371 | |
1495cc9d | 372 | static void sysrq_handle_moom(int key) |
1da177e4 LT |
373 | { |
374 | schedule_work(&moom_work); | |
375 | } | |
376 | static struct sysrq_key_op sysrq_moom_op = { | |
377 | .handler = sysrq_handle_moom, | |
afa80ccb | 378 | .help_msg = "memory-full-oom-kill(f)", |
1da177e4 | 379 | .action_msg = "Manual OOM execution", |
b4236f81 | 380 | .enable_mask = SYSRQ_ENABLE_SIGNAL, |
1da177e4 LT |
381 | }; |
382 | ||
c2d75438 | 383 | #ifdef CONFIG_BLOCK |
1495cc9d | 384 | static void sysrq_handle_thaw(int key) |
c2d75438 ES |
385 | { |
386 | emergency_thaw_all(); | |
387 | } | |
388 | static struct sysrq_key_op sysrq_thaw_op = { | |
389 | .handler = sysrq_handle_thaw, | |
afa80ccb | 390 | .help_msg = "thaw-filesystems(j)", |
c2d75438 ES |
391 | .action_msg = "Emergency Thaw of all frozen filesystems", |
392 | .enable_mask = SYSRQ_ENABLE_SIGNAL, | |
393 | }; | |
394 | #endif | |
395 | ||
1495cc9d | 396 | static void sysrq_handle_kill(int key) |
1da177e4 LT |
397 | { |
398 | send_sig_all(SIGKILL); | |
a8fe19eb | 399 | console_loglevel = CONSOLE_LOGLEVEL_DEBUG; |
1da177e4 LT |
400 | } |
401 | static struct sysrq_key_op sysrq_kill_op = { | |
402 | .handler = sysrq_handle_kill, | |
afa80ccb | 403 | .help_msg = "kill-all-tasks(i)", |
1da177e4 LT |
404 | .action_msg = "Kill All Tasks", |
405 | .enable_mask = SYSRQ_ENABLE_SIGNAL, | |
406 | }; | |
407 | ||
1495cc9d | 408 | static void sysrq_handle_unrt(int key) |
1da177e4 LT |
409 | { |
410 | normalize_rt_tasks(); | |
411 | } | |
412 | static struct sysrq_key_op sysrq_unrt_op = { | |
413 | .handler = sysrq_handle_unrt, | |
afa80ccb | 414 | .help_msg = "nice-all-RT-tasks(n)", |
1da177e4 LT |
415 | .action_msg = "Nice All RT Tasks", |
416 | .enable_mask = SYSRQ_ENABLE_RTNICE, | |
417 | }; | |
418 | ||
419 | /* Key Operations table and lock */ | |
420 | static DEFINE_SPINLOCK(sysrq_key_table_lock); | |
bf36b901 AM |
421 | |
422 | static struct sysrq_key_op *sysrq_key_table[36] = { | |
423 | &sysrq_loglevel_op, /* 0 */ | |
424 | &sysrq_loglevel_op, /* 1 */ | |
425 | &sysrq_loglevel_op, /* 2 */ | |
426 | &sysrq_loglevel_op, /* 3 */ | |
427 | &sysrq_loglevel_op, /* 4 */ | |
428 | &sysrq_loglevel_op, /* 5 */ | |
429 | &sysrq_loglevel_op, /* 6 */ | |
430 | &sysrq_loglevel_op, /* 7 */ | |
431 | &sysrq_loglevel_op, /* 8 */ | |
432 | &sysrq_loglevel_op, /* 9 */ | |
433 | ||
434 | /* | |
d346cce3 RD |
435 | * a: Don't use for system provided sysrqs, it is handled specially on |
436 | * sparc and will never arrive. | |
bf36b901 AM |
437 | */ |
438 | NULL, /* a */ | |
439 | &sysrq_reboot_op, /* b */ | |
cab8bd34 | 440 | &sysrq_crash_op, /* c & ibm_emac driver debug */ |
bf36b901 AM |
441 | &sysrq_showlocks_op, /* d */ |
442 | &sysrq_term_op, /* e */ | |
443 | &sysrq_moom_op, /* f */ | |
364b5b7b | 444 | /* g: May be registered for the kernel debugger */ |
bf36b901 | 445 | NULL, /* g */ |
c2d75438 | 446 | NULL, /* h - reserved for help */ |
bf36b901 | 447 | &sysrq_kill_op, /* i */ |
c2d75438 ES |
448 | #ifdef CONFIG_BLOCK |
449 | &sysrq_thaw_op, /* j */ | |
450 | #else | |
bf36b901 | 451 | NULL, /* j */ |
c2d75438 | 452 | #endif |
bf36b901 | 453 | &sysrq_SAK_op, /* k */ |
5045bcae RR |
454 | #ifdef CONFIG_SMP |
455 | &sysrq_showallcpus_op, /* l */ | |
456 | #else | |
bf36b901 | 457 | NULL, /* l */ |
5045bcae | 458 | #endif |
bf36b901 AM |
459 | &sysrq_showmem_op, /* m */ |
460 | &sysrq_unrt_op, /* n */ | |
d346cce3 | 461 | /* o: This will often be registered as 'Off' at init time */ |
bf36b901 AM |
462 | NULL, /* o */ |
463 | &sysrq_showregs_op, /* p */ | |
88ad0bf6 | 464 | &sysrq_show_timers_op, /* q */ |
d346cce3 | 465 | &sysrq_unraw_op, /* r */ |
bf36b901 AM |
466 | &sysrq_sync_op, /* s */ |
467 | &sysrq_showstate_op, /* t */ | |
468 | &sysrq_mountro_op, /* u */ | |
364b5b7b | 469 | /* v: May be registered for frame buffer console restore */ |
bf36b901 | 470 | NULL, /* v */ |
d346cce3 | 471 | &sysrq_showstate_blocked_op, /* w */ |
d1e9a4f5 | 472 | /* x: May be registered on mips for TLB dump */ |
d346cce3 | 473 | /* x: May be registered on ppc/powerpc for xmon */ |
916ca14a | 474 | /* x: May be registered on sparc64 for global PMU dump */ |
d346cce3 | 475 | NULL, /* x */ |
93dae5b7 | 476 | /* y: May be registered on sparc64 for global register dump */ |
bf36b901 | 477 | NULL, /* y */ |
69f698ad | 478 | &sysrq_ftrace_dump_op, /* z */ |
1da177e4 LT |
479 | }; |
480 | ||
481 | /* key2index calculation, -1 on invalid index */ | |
bf36b901 AM |
482 | static int sysrq_key_table_key2index(int key) |
483 | { | |
1da177e4 | 484 | int retval; |
bf36b901 AM |
485 | |
486 | if ((key >= '0') && (key <= '9')) | |
1da177e4 | 487 | retval = key - '0'; |
bf36b901 | 488 | else if ((key >= 'a') && (key <= 'z')) |
1da177e4 | 489 | retval = key + 10 - 'a'; |
bf36b901 | 490 | else |
1da177e4 | 491 | retval = -1; |
1da177e4 LT |
492 | return retval; |
493 | } | |
494 | ||
495 | /* | |
496 | * get and put functions for the table, exposed to modules. | |
497 | */ | |
bf36b901 AM |
498 | struct sysrq_key_op *__sysrq_get_key_op(int key) |
499 | { | |
500 | struct sysrq_key_op *op_p = NULL; | |
1da177e4 | 501 | int i; |
bf36b901 | 502 | |
1da177e4 | 503 | i = sysrq_key_table_key2index(key); |
bf36b901 AM |
504 | if (i != -1) |
505 | op_p = sysrq_key_table[i]; | |
97f5f0cd | 506 | |
1da177e4 LT |
507 | return op_p; |
508 | } | |
509 | ||
bf36b901 AM |
510 | static void __sysrq_put_key_op(int key, struct sysrq_key_op *op_p) |
511 | { | |
512 | int i = sysrq_key_table_key2index(key); | |
1da177e4 | 513 | |
1da177e4 LT |
514 | if (i != -1) |
515 | sysrq_key_table[i] = op_p; | |
516 | } | |
517 | ||
f335397d | 518 | void __handle_sysrq(int key, bool check_mask) |
1da177e4 LT |
519 | { |
520 | struct sysrq_key_op *op_p; | |
521 | int orig_log_level; | |
bf36b901 | 522 | int i; |
1da177e4 | 523 | |
722773af | 524 | rcu_sysrq_start(); |
984d74a7 | 525 | rcu_read_lock(); |
fb144adc AW |
526 | /* |
527 | * Raise the apparent loglevel to maximum so that the sysrq header | |
528 | * is shown to provide the user with positive feedback. We do not | |
529 | * simply emit this at KERN_EMERG as that would change message | |
530 | * routing in the consumers of /proc/kmsg. | |
531 | */ | |
1da177e4 | 532 | orig_log_level = console_loglevel; |
a8fe19eb | 533 | console_loglevel = CONSOLE_LOGLEVEL_DEFAULT; |
401e4a7c | 534 | pr_info("SysRq : "); |
1da177e4 LT |
535 | |
536 | op_p = __sysrq_get_key_op(key); | |
537 | if (op_p) { | |
bf36b901 AM |
538 | /* |
539 | * Should we check for enabled operations (/proc/sysrq-trigger | |
540 | * should not) and is the invoked operation enabled? | |
541 | */ | |
5d6f647f | 542 | if (!check_mask || sysrq_on_mask(op_p->enable_mask)) { |
401e4a7c | 543 | pr_cont("%s\n", op_p->action_msg); |
1da177e4 | 544 | console_loglevel = orig_log_level; |
1495cc9d | 545 | op_p->handler(key); |
bf36b901 | 546 | } else { |
401e4a7c | 547 | pr_cont("This sysrq operation is disabled.\n"); |
bf36b901 | 548 | } |
1da177e4 | 549 | } else { |
401e4a7c | 550 | pr_cont("HELP : "); |
1da177e4 | 551 | /* Only print the help msg once per handler */ |
bf36b901 AM |
552 | for (i = 0; i < ARRAY_SIZE(sysrq_key_table); i++) { |
553 | if (sysrq_key_table[i]) { | |
554 | int j; | |
555 | ||
556 | for (j = 0; sysrq_key_table[i] != | |
557 | sysrq_key_table[j]; j++) | |
558 | ; | |
559 | if (j != i) | |
560 | continue; | |
401e4a7c | 561 | pr_cont("%s ", sysrq_key_table[i]->help_msg); |
bf36b901 | 562 | } |
1da177e4 | 563 | } |
401e4a7c | 564 | pr_cont("\n"); |
1da177e4 LT |
565 | console_loglevel = orig_log_level; |
566 | } | |
984d74a7 | 567 | rcu_read_unlock(); |
722773af | 568 | rcu_sysrq_end(); |
1da177e4 LT |
569 | } |
570 | ||
f335397d | 571 | void handle_sysrq(int key) |
1da177e4 | 572 | { |
5d6f647f | 573 | if (sysrq_on()) |
f335397d | 574 | __handle_sysrq(key, true); |
1da177e4 | 575 | } |
bf36b901 | 576 | EXPORT_SYMBOL(handle_sysrq); |
1da177e4 | 577 | |
97f5f0cd | 578 | #ifdef CONFIG_INPUT |
ffb6e0c9 | 579 | static int sysrq_reset_downtime_ms; |
97f5f0cd DT |
580 | |
581 | /* Simple translation table for the SysRq keys */ | |
fcb71930 | 582 | static const unsigned char sysrq_xlate[KEY_CNT] = |
97f5f0cd DT |
583 | "\000\0331234567890-=\177\t" /* 0x00 - 0x0f */ |
584 | "qwertyuiop[]\r\000as" /* 0x10 - 0x1f */ | |
585 | "dfghjkl;'`\000\\zxcv" /* 0x20 - 0x2f */ | |
586 | "bnm,./\000*\000 \000\201\202\203\204\205" /* 0x30 - 0x3f */ | |
587 | "\206\207\210\211\212\000\000789-456+1" /* 0x40 - 0x4f */ | |
588 | "230\177\000\000\213\214\000\000\000\000\000\000\000\000\000\000" /* 0x50 - 0x5f */ | |
589 | "\r\000/"; /* 0x60 - 0x6f */ | |
590 | ||
fcb71930 DT |
591 | struct sysrq_state { |
592 | struct input_handle handle; | |
593 | struct work_struct reinject_work; | |
594 | unsigned long key_down[BITS_TO_LONGS(KEY_CNT)]; | |
595 | unsigned int alt; | |
596 | unsigned int alt_use; | |
597 | bool active; | |
598 | bool need_reinject; | |
7ab7b5ad | 599 | bool reinjecting; |
154b7a48 MP |
600 | |
601 | /* reset sequence handling */ | |
602 | bool reset_canceled; | |
3d289517 | 603 | bool reset_requested; |
154b7a48 MP |
604 | unsigned long reset_keybit[BITS_TO_LONGS(KEY_CNT)]; |
605 | int reset_seq_len; | |
606 | int reset_seq_cnt; | |
607 | int reset_seq_version; | |
39030786 | 608 | struct timer_list keyreset_timer; |
fcb71930 DT |
609 | }; |
610 | ||
154b7a48 MP |
611 | #define SYSRQ_KEY_RESET_MAX 20 /* Should be plenty */ |
612 | static unsigned short sysrq_reset_seq[SYSRQ_KEY_RESET_MAX]; | |
613 | static unsigned int sysrq_reset_seq_len; | |
614 | static unsigned int sysrq_reset_seq_version = 1; | |
615 | ||
616 | static void sysrq_parse_reset_sequence(struct sysrq_state *state) | |
617 | { | |
618 | int i; | |
619 | unsigned short key; | |
620 | ||
621 | state->reset_seq_cnt = 0; | |
622 | ||
623 | for (i = 0; i < sysrq_reset_seq_len; i++) { | |
624 | key = sysrq_reset_seq[i]; | |
625 | ||
626 | if (key == KEY_RESERVED || key > KEY_MAX) | |
627 | break; | |
628 | ||
629 | __set_bit(key, state->reset_keybit); | |
630 | state->reset_seq_len++; | |
631 | ||
632 | if (test_bit(key, state->key_down)) | |
633 | state->reset_seq_cnt++; | |
634 | } | |
635 | ||
636 | /* Disable reset until old keys are not released */ | |
637 | state->reset_canceled = state->reset_seq_cnt != 0; | |
638 | ||
639 | state->reset_seq_version = sysrq_reset_seq_version; | |
640 | } | |
641 | ||
3d289517 | 642 | static void sysrq_do_reset(unsigned long _state) |
39030786 | 643 | { |
3d289517 MP |
644 | struct sysrq_state *state = (struct sysrq_state *) _state; |
645 | ||
646 | state->reset_requested = true; | |
647 | ||
648 | sys_sync(); | |
649 | kernel_restart(NULL); | |
39030786 MP |
650 | } |
651 | ||
652 | static void sysrq_handle_reset_request(struct sysrq_state *state) | |
653 | { | |
3d289517 MP |
654 | if (state->reset_requested) |
655 | __handle_sysrq(sysrq_xlate[KEY_B], false); | |
656 | ||
39030786 MP |
657 | if (sysrq_reset_downtime_ms) |
658 | mod_timer(&state->keyreset_timer, | |
659 | jiffies + msecs_to_jiffies(sysrq_reset_downtime_ms)); | |
660 | else | |
3d289517 | 661 | sysrq_do_reset((unsigned long)state); |
39030786 MP |
662 | } |
663 | ||
664 | static void sysrq_detect_reset_sequence(struct sysrq_state *state, | |
154b7a48 MP |
665 | unsigned int code, int value) |
666 | { | |
667 | if (!test_bit(code, state->reset_keybit)) { | |
668 | /* | |
669 | * Pressing any key _not_ in reset sequence cancels | |
39030786 MP |
670 | * the reset sequence. Also cancelling the timer in |
671 | * case additional keys were pressed after a reset | |
672 | * has been requested. | |
154b7a48 | 673 | */ |
39030786 | 674 | if (value && state->reset_seq_cnt) { |
154b7a48 | 675 | state->reset_canceled = true; |
39030786 MP |
676 | del_timer(&state->keyreset_timer); |
677 | } | |
154b7a48 | 678 | } else if (value == 0) { |
39030786 MP |
679 | /* |
680 | * Key release - all keys in the reset sequence need | |
681 | * to be pressed and held for the reset timeout | |
682 | * to hold. | |
683 | */ | |
684 | del_timer(&state->keyreset_timer); | |
685 | ||
154b7a48 MP |
686 | if (--state->reset_seq_cnt == 0) |
687 | state->reset_canceled = false; | |
688 | } else if (value == 1) { | |
689 | /* key press, not autorepeat */ | |
690 | if (++state->reset_seq_cnt == state->reset_seq_len && | |
691 | !state->reset_canceled) { | |
39030786 | 692 | sysrq_handle_reset_request(state); |
154b7a48 MP |
693 | } |
694 | } | |
154b7a48 MP |
695 | } |
696 | ||
4c076eb0 MP |
697 | #ifdef CONFIG_OF |
698 | static void sysrq_of_get_keyreset_config(void) | |
699 | { | |
700 | u32 key; | |
701 | struct device_node *np; | |
702 | struct property *prop; | |
703 | const __be32 *p; | |
704 | ||
705 | np = of_find_node_by_path("/chosen/linux,sysrq-reset-seq"); | |
706 | if (!np) { | |
707 | pr_debug("No sysrq node found"); | |
708 | return; | |
709 | } | |
710 | ||
711 | /* Reset in case a __weak definition was present */ | |
712 | sysrq_reset_seq_len = 0; | |
713 | ||
714 | of_property_for_each_u32(np, "keyset", prop, p, key) { | |
715 | if (key == KEY_RESERVED || key > KEY_MAX || | |
716 | sysrq_reset_seq_len == SYSRQ_KEY_RESET_MAX) | |
717 | break; | |
718 | ||
719 | sysrq_reset_seq[sysrq_reset_seq_len++] = (unsigned short)key; | |
720 | } | |
721 | ||
722 | /* Get reset timeout if any. */ | |
723 | of_property_read_u32(np, "timeout-ms", &sysrq_reset_downtime_ms); | |
724 | } | |
725 | #else | |
726 | static void sysrq_of_get_keyreset_config(void) | |
727 | { | |
728 | } | |
729 | #endif | |
730 | ||
fcb71930 DT |
731 | static void sysrq_reinject_alt_sysrq(struct work_struct *work) |
732 | { | |
733 | struct sysrq_state *sysrq = | |
734 | container_of(work, struct sysrq_state, reinject_work); | |
735 | struct input_handle *handle = &sysrq->handle; | |
736 | unsigned int alt_code = sysrq->alt_use; | |
737 | ||
738 | if (sysrq->need_reinject) { | |
7ab7b5ad DT |
739 | /* we do not want the assignment to be reordered */ |
740 | sysrq->reinjecting = true; | |
741 | mb(); | |
742 | ||
fcb71930 DT |
743 | /* Simulate press and release of Alt + SysRq */ |
744 | input_inject_event(handle, EV_KEY, alt_code, 1); | |
745 | input_inject_event(handle, EV_KEY, KEY_SYSRQ, 1); | |
746 | input_inject_event(handle, EV_SYN, SYN_REPORT, 1); | |
747 | ||
748 | input_inject_event(handle, EV_KEY, KEY_SYSRQ, 0); | |
749 | input_inject_event(handle, EV_KEY, alt_code, 0); | |
750 | input_inject_event(handle, EV_SYN, SYN_REPORT, 1); | |
7ab7b5ad DT |
751 | |
752 | mb(); | |
753 | sysrq->reinjecting = false; | |
fcb71930 DT |
754 | } |
755 | } | |
97f5f0cd | 756 | |
154b7a48 MP |
757 | static bool sysrq_handle_keypress(struct sysrq_state *sysrq, |
758 | unsigned int code, int value) | |
97f5f0cd | 759 | { |
fcb71930 | 760 | bool was_active = sysrq->active; |
1966cb22 DT |
761 | bool suppress; |
762 | ||
154b7a48 | 763 | switch (code) { |
7ab7b5ad | 764 | |
154b7a48 MP |
765 | case KEY_LEFTALT: |
766 | case KEY_RIGHTALT: | |
767 | if (!value) { | |
768 | /* One of ALTs is being released */ | |
769 | if (sysrq->active && code == sysrq->alt_use) | |
770 | sysrq->active = false; | |
1966cb22 | 771 | |
154b7a48 MP |
772 | sysrq->alt = KEY_RESERVED; |
773 | ||
774 | } else if (value != 2) { | |
775 | sysrq->alt = code; | |
776 | sysrq->need_reinject = false; | |
777 | } | |
fcb71930 | 778 | break; |
97f5f0cd | 779 | |
154b7a48 MP |
780 | case KEY_SYSRQ: |
781 | if (value == 1 && sysrq->alt != KEY_RESERVED) { | |
782 | sysrq->active = true; | |
783 | sysrq->alt_use = sysrq->alt; | |
784 | /* | |
785 | * If nothing else will be pressed we'll need | |
786 | * to re-inject Alt-SysRq keysroke. | |
787 | */ | |
788 | sysrq->need_reinject = true; | |
789 | } | |
97f5f0cd | 790 | |
154b7a48 MP |
791 | /* |
792 | * Pretend that sysrq was never pressed at all. This | |
793 | * is needed to properly handle KGDB which will try | |
794 | * to release all keys after exiting debugger. If we | |
795 | * do not clear key bit it KGDB will end up sending | |
796 | * release events for Alt and SysRq, potentially | |
797 | * triggering print screen function. | |
798 | */ | |
799 | if (sysrq->active) | |
800 | clear_bit(KEY_SYSRQ, sysrq->handle.dev->key); | |
f5dec511 | 801 | |
154b7a48 | 802 | break; |
fcb71930 | 803 | |
154b7a48 MP |
804 | default: |
805 | if (sysrq->active && value && value != 2) { | |
806 | sysrq->need_reinject = false; | |
807 | __handle_sysrq(sysrq_xlate[code], true); | |
808 | } | |
809 | break; | |
810 | } | |
fcb71930 | 811 | |
154b7a48 | 812 | suppress = sysrq->active; |
fcb71930 | 813 | |
154b7a48 | 814 | if (!sysrq->active) { |
fcb71930 | 815 | |
154b7a48 MP |
816 | /* |
817 | * See if reset sequence has changed since the last time. | |
818 | */ | |
819 | if (sysrq->reset_seq_version != sysrq_reset_seq_version) | |
820 | sysrq_parse_reset_sequence(sysrq); | |
fcb71930 | 821 | |
154b7a48 MP |
822 | /* |
823 | * If we are not suppressing key presses keep track of | |
824 | * keyboard state so we can release keys that have been | |
825 | * pressed before entering SysRq mode. | |
826 | */ | |
827 | if (value) | |
828 | set_bit(code, sysrq->key_down); | |
829 | else | |
830 | clear_bit(code, sysrq->key_down); | |
831 | ||
832 | if (was_active) | |
833 | schedule_work(&sysrq->reinject_work); | |
834 | ||
39030786 MP |
835 | /* Check for reset sequence */ |
836 | sysrq_detect_reset_sequence(sysrq, code, value); | |
97f5f0cd | 837 | |
154b7a48 MP |
838 | } else if (value == 0 && test_and_clear_bit(code, sysrq->key_down)) { |
839 | /* | |
840 | * Pass on release events for keys that was pressed before | |
841 | * entering SysRq mode. | |
842 | */ | |
843 | suppress = false; | |
844 | } | |
fcb71930 | 845 | |
154b7a48 MP |
846 | return suppress; |
847 | } | |
fcb71930 | 848 | |
154b7a48 MP |
849 | static bool sysrq_filter(struct input_handle *handle, |
850 | unsigned int type, unsigned int code, int value) | |
851 | { | |
852 | struct sysrq_state *sysrq = handle->private; | |
853 | bool suppress; | |
fcb71930 | 854 | |
154b7a48 MP |
855 | /* |
856 | * Do not filter anything if we are in the process of re-injecting | |
857 | * Alt+SysRq combination. | |
858 | */ | |
859 | if (sysrq->reinjecting) | |
860 | return false; | |
861 | ||
862 | switch (type) { | |
863 | ||
864 | case EV_SYN: | |
865 | suppress = false; | |
866 | break; | |
867 | ||
868 | case EV_KEY: | |
869 | suppress = sysrq_handle_keypress(sysrq, code, value); | |
97f5f0cd DT |
870 | break; |
871 | ||
872 | default: | |
fcb71930 | 873 | suppress = sysrq->active; |
97f5f0cd DT |
874 | break; |
875 | } | |
876 | ||
1966cb22 | 877 | return suppress; |
97f5f0cd DT |
878 | } |
879 | ||
880 | static int sysrq_connect(struct input_handler *handler, | |
881 | struct input_dev *dev, | |
882 | const struct input_device_id *id) | |
883 | { | |
fcb71930 | 884 | struct sysrq_state *sysrq; |
97f5f0cd DT |
885 | int error; |
886 | ||
fcb71930 DT |
887 | sysrq = kzalloc(sizeof(struct sysrq_state), GFP_KERNEL); |
888 | if (!sysrq) | |
97f5f0cd DT |
889 | return -ENOMEM; |
890 | ||
fcb71930 DT |
891 | INIT_WORK(&sysrq->reinject_work, sysrq_reinject_alt_sysrq); |
892 | ||
893 | sysrq->handle.dev = dev; | |
894 | sysrq->handle.handler = handler; | |
895 | sysrq->handle.name = "sysrq"; | |
896 | sysrq->handle.private = sysrq; | |
3d289517 MP |
897 | setup_timer(&sysrq->keyreset_timer, |
898 | sysrq_do_reset, (unsigned long)sysrq); | |
97f5f0cd | 899 | |
fcb71930 | 900 | error = input_register_handle(&sysrq->handle); |
97f5f0cd DT |
901 | if (error) { |
902 | pr_err("Failed to register input sysrq handler, error %d\n", | |
903 | error); | |
904 | goto err_free; | |
905 | } | |
906 | ||
fcb71930 | 907 | error = input_open_device(&sysrq->handle); |
97f5f0cd DT |
908 | if (error) { |
909 | pr_err("Failed to open input device, error %d\n", error); | |
910 | goto err_unregister; | |
911 | } | |
912 | ||
913 | return 0; | |
914 | ||
915 | err_unregister: | |
fcb71930 | 916 | input_unregister_handle(&sysrq->handle); |
97f5f0cd | 917 | err_free: |
fcb71930 | 918 | kfree(sysrq); |
97f5f0cd DT |
919 | return error; |
920 | } | |
921 | ||
922 | static void sysrq_disconnect(struct input_handle *handle) | |
923 | { | |
fcb71930 DT |
924 | struct sysrq_state *sysrq = handle->private; |
925 | ||
97f5f0cd | 926 | input_close_device(handle); |
fcb71930 | 927 | cancel_work_sync(&sysrq->reinject_work); |
39030786 | 928 | del_timer_sync(&sysrq->keyreset_timer); |
97f5f0cd | 929 | input_unregister_handle(handle); |
fcb71930 | 930 | kfree(sysrq); |
97f5f0cd DT |
931 | } |
932 | ||
933 | /* | |
1966cb22 DT |
934 | * We are matching on KEY_LEFTALT instead of KEY_SYSRQ because not all |
935 | * keyboards have SysRq key predefined and so user may add it to keymap | |
97f5f0cd DT |
936 | * later, but we expect all such keyboards to have left alt. |
937 | */ | |
938 | static const struct input_device_id sysrq_ids[] = { | |
939 | { | |
940 | .flags = INPUT_DEVICE_ID_MATCH_EVBIT | | |
941 | INPUT_DEVICE_ID_MATCH_KEYBIT, | |
942 | .evbit = { BIT_MASK(EV_KEY) }, | |
943 | .keybit = { BIT_MASK(KEY_LEFTALT) }, | |
944 | }, | |
945 | { }, | |
946 | }; | |
947 | ||
948 | static struct input_handler sysrq_handler = { | |
949 | .filter = sysrq_filter, | |
950 | .connect = sysrq_connect, | |
951 | .disconnect = sysrq_disconnect, | |
952 | .name = "sysrq", | |
953 | .id_table = sysrq_ids, | |
954 | }; | |
955 | ||
956 | static bool sysrq_handler_registered; | |
957 | ||
958 | static inline void sysrq_register_handler(void) | |
959 | { | |
960 | int error; | |
961 | ||
4c076eb0 MP |
962 | sysrq_of_get_keyreset_config(); |
963 | ||
97f5f0cd DT |
964 | error = input_register_handler(&sysrq_handler); |
965 | if (error) | |
966 | pr_err("Failed to register input handler, error %d", error); | |
967 | else | |
968 | sysrq_handler_registered = true; | |
969 | } | |
970 | ||
971 | static inline void sysrq_unregister_handler(void) | |
972 | { | |
973 | if (sysrq_handler_registered) { | |
974 | input_unregister_handler(&sysrq_handler); | |
975 | sysrq_handler_registered = false; | |
976 | } | |
977 | } | |
978 | ||
154b7a48 MP |
979 | static int sysrq_reset_seq_param_set(const char *buffer, |
980 | const struct kernel_param *kp) | |
981 | { | |
982 | unsigned long val; | |
983 | int error; | |
984 | ||
86b40567 | 985 | error = kstrtoul(buffer, 0, &val); |
154b7a48 MP |
986 | if (error < 0) |
987 | return error; | |
988 | ||
989 | if (val > KEY_MAX) | |
990 | return -EINVAL; | |
991 | ||
992 | *((unsigned short *)kp->arg) = val; | |
993 | sysrq_reset_seq_version++; | |
994 | ||
995 | return 0; | |
996 | } | |
997 | ||
9c27847d | 998 | static const struct kernel_param_ops param_ops_sysrq_reset_seq = { |
154b7a48 MP |
999 | .get = param_get_ushort, |
1000 | .set = sysrq_reset_seq_param_set, | |
1001 | }; | |
1002 | ||
1003 | #define param_check_sysrq_reset_seq(name, p) \ | |
1004 | __param_check(name, p, unsigned short) | |
1005 | ||
3bce6f64 PG |
1006 | /* |
1007 | * not really modular, but the easiest way to keep compat with existing | |
1008 | * bootargs behaviour is to continue using module_param here. | |
1009 | */ | |
154b7a48 MP |
1010 | module_param_array_named(reset_seq, sysrq_reset_seq, sysrq_reset_seq, |
1011 | &sysrq_reset_seq_len, 0644); | |
1012 | ||
39030786 MP |
1013 | module_param_named(sysrq_downtime_ms, sysrq_reset_downtime_ms, int, 0644); |
1014 | ||
97f5f0cd DT |
1015 | #else |
1016 | ||
1017 | static inline void sysrq_register_handler(void) | |
1018 | { | |
1019 | } | |
1020 | ||
1021 | static inline void sysrq_unregister_handler(void) | |
1022 | { | |
1023 | } | |
1024 | ||
1025 | #endif /* CONFIG_INPUT */ | |
1026 | ||
1027 | int sysrq_toggle_support(int enable_mask) | |
1028 | { | |
1029 | bool was_enabled = sysrq_on(); | |
1030 | ||
1031 | sysrq_enabled = enable_mask; | |
1032 | ||
1033 | if (was_enabled != sysrq_on()) { | |
1034 | if (sysrq_on()) | |
1035 | sysrq_register_handler(); | |
1036 | else | |
1037 | sysrq_unregister_handler(); | |
1038 | } | |
1039 | ||
1040 | return 0; | |
1041 | } | |
1042 | ||
cf62ddce | 1043 | static int __sysrq_swap_key_ops(int key, struct sysrq_key_op *insert_op_p, |
bf36b901 AM |
1044 | struct sysrq_key_op *remove_op_p) |
1045 | { | |
1da177e4 | 1046 | int retval; |
1da177e4 | 1047 | |
984d74a7 | 1048 | spin_lock(&sysrq_key_table_lock); |
1da177e4 LT |
1049 | if (__sysrq_get_key_op(key) == remove_op_p) { |
1050 | __sysrq_put_key_op(key, insert_op_p); | |
1051 | retval = 0; | |
1052 | } else { | |
1053 | retval = -1; | |
1054 | } | |
984d74a7 RR |
1055 | spin_unlock(&sysrq_key_table_lock); |
1056 | ||
1057 | /* | |
1058 | * A concurrent __handle_sysrq either got the old op or the new op. | |
1059 | * Wait for it to go away before returning, so the code for an old | |
1060 | * op is not freed (eg. on module unload) while it is in use. | |
1061 | */ | |
1062 | synchronize_rcu(); | |
1063 | ||
1da177e4 LT |
1064 | return retval; |
1065 | } | |
1066 | ||
1067 | int register_sysrq_key(int key, struct sysrq_key_op *op_p) | |
1068 | { | |
1069 | return __sysrq_swap_key_ops(key, op_p, NULL); | |
1070 | } | |
bf36b901 | 1071 | EXPORT_SYMBOL(register_sysrq_key); |
1da177e4 LT |
1072 | |
1073 | int unregister_sysrq_key(int key, struct sysrq_key_op *op_p) | |
1074 | { | |
1075 | return __sysrq_swap_key_ops(key, NULL, op_p); | |
1076 | } | |
1da177e4 | 1077 | EXPORT_SYMBOL(unregister_sysrq_key); |
f40cbaa5 AD |
1078 | |
1079 | #ifdef CONFIG_PROC_FS | |
1080 | /* | |
1081 | * writing 'C' to /proc/sysrq-trigger is like sysrq-C | |
1082 | */ | |
1083 | static ssize_t write_sysrq_trigger(struct file *file, const char __user *buf, | |
1084 | size_t count, loff_t *ppos) | |
1085 | { | |
1086 | if (count) { | |
1087 | char c; | |
1088 | ||
1089 | if (get_user(c, buf)) | |
1090 | return -EFAULT; | |
f335397d | 1091 | __handle_sysrq(c, false); |
f40cbaa5 | 1092 | } |
97f5f0cd | 1093 | |
f40cbaa5 AD |
1094 | return count; |
1095 | } | |
1096 | ||
1097 | static const struct file_operations proc_sysrq_trigger_operations = { | |
1098 | .write = write_sysrq_trigger, | |
6038f373 | 1099 | .llseek = noop_llseek, |
f40cbaa5 AD |
1100 | }; |
1101 | ||
97f5f0cd DT |
1102 | static void sysrq_init_procfs(void) |
1103 | { | |
1104 | if (!proc_create("sysrq-trigger", S_IWUSR, NULL, | |
1105 | &proc_sysrq_trigger_operations)) | |
1106 | pr_err("Failed to register proc interface\n"); | |
1107 | } | |
1108 | ||
1109 | #else | |
1110 | ||
1111 | static inline void sysrq_init_procfs(void) | |
1112 | { | |
1113 | } | |
1114 | ||
1115 | #endif /* CONFIG_PROC_FS */ | |
1116 | ||
f40cbaa5 AD |
1117 | static int __init sysrq_init(void) |
1118 | { | |
97f5f0cd DT |
1119 | sysrq_init_procfs(); |
1120 | ||
1121 | if (sysrq_on()) | |
1122 | sysrq_register_handler(); | |
1123 | ||
f40cbaa5 AD |
1124 | return 0; |
1125 | } | |
3bce6f64 | 1126 | device_initcall(sysrq_init); |