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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 | 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 | { |
dc56401f | 356 | mutex_lock(&oom_lock); |
c32b3cbe MH |
357 | if (!out_of_memory(node_zonelist(first_memory_node, GFP_KERNEL), |
358 | GFP_KERNEL, 0, NULL, true)) | |
359 | pr_info("OOM request ignored because killer is disabled\n"); | |
dc56401f | 360 | mutex_unlock(&oom_lock); |
1da177e4 LT |
361 | } |
362 | ||
65f27f38 | 363 | static DECLARE_WORK(moom_work, moom_callback); |
1da177e4 | 364 | |
1495cc9d | 365 | static void sysrq_handle_moom(int key) |
1da177e4 LT |
366 | { |
367 | schedule_work(&moom_work); | |
368 | } | |
369 | static struct sysrq_key_op sysrq_moom_op = { | |
370 | .handler = sysrq_handle_moom, | |
afa80ccb | 371 | .help_msg = "memory-full-oom-kill(f)", |
1da177e4 | 372 | .action_msg = "Manual OOM execution", |
b4236f81 | 373 | .enable_mask = SYSRQ_ENABLE_SIGNAL, |
1da177e4 LT |
374 | }; |
375 | ||
c2d75438 | 376 | #ifdef CONFIG_BLOCK |
1495cc9d | 377 | static void sysrq_handle_thaw(int key) |
c2d75438 ES |
378 | { |
379 | emergency_thaw_all(); | |
380 | } | |
381 | static struct sysrq_key_op sysrq_thaw_op = { | |
382 | .handler = sysrq_handle_thaw, | |
afa80ccb | 383 | .help_msg = "thaw-filesystems(j)", |
c2d75438 ES |
384 | .action_msg = "Emergency Thaw of all frozen filesystems", |
385 | .enable_mask = SYSRQ_ENABLE_SIGNAL, | |
386 | }; | |
387 | #endif | |
388 | ||
1495cc9d | 389 | static void sysrq_handle_kill(int key) |
1da177e4 LT |
390 | { |
391 | send_sig_all(SIGKILL); | |
a8fe19eb | 392 | console_loglevel = CONSOLE_LOGLEVEL_DEBUG; |
1da177e4 LT |
393 | } |
394 | static struct sysrq_key_op sysrq_kill_op = { | |
395 | .handler = sysrq_handle_kill, | |
afa80ccb | 396 | .help_msg = "kill-all-tasks(i)", |
1da177e4 LT |
397 | .action_msg = "Kill All Tasks", |
398 | .enable_mask = SYSRQ_ENABLE_SIGNAL, | |
399 | }; | |
400 | ||
1495cc9d | 401 | static void sysrq_handle_unrt(int key) |
1da177e4 LT |
402 | { |
403 | normalize_rt_tasks(); | |
404 | } | |
405 | static struct sysrq_key_op sysrq_unrt_op = { | |
406 | .handler = sysrq_handle_unrt, | |
afa80ccb | 407 | .help_msg = "nice-all-RT-tasks(n)", |
1da177e4 LT |
408 | .action_msg = "Nice All RT Tasks", |
409 | .enable_mask = SYSRQ_ENABLE_RTNICE, | |
410 | }; | |
411 | ||
412 | /* Key Operations table and lock */ | |
413 | static DEFINE_SPINLOCK(sysrq_key_table_lock); | |
bf36b901 AM |
414 | |
415 | static struct sysrq_key_op *sysrq_key_table[36] = { | |
416 | &sysrq_loglevel_op, /* 0 */ | |
417 | &sysrq_loglevel_op, /* 1 */ | |
418 | &sysrq_loglevel_op, /* 2 */ | |
419 | &sysrq_loglevel_op, /* 3 */ | |
420 | &sysrq_loglevel_op, /* 4 */ | |
421 | &sysrq_loglevel_op, /* 5 */ | |
422 | &sysrq_loglevel_op, /* 6 */ | |
423 | &sysrq_loglevel_op, /* 7 */ | |
424 | &sysrq_loglevel_op, /* 8 */ | |
425 | &sysrq_loglevel_op, /* 9 */ | |
426 | ||
427 | /* | |
d346cce3 RD |
428 | * a: Don't use for system provided sysrqs, it is handled specially on |
429 | * sparc and will never arrive. | |
bf36b901 AM |
430 | */ |
431 | NULL, /* a */ | |
432 | &sysrq_reboot_op, /* b */ | |
cab8bd34 | 433 | &sysrq_crash_op, /* c & ibm_emac driver debug */ |
bf36b901 AM |
434 | &sysrq_showlocks_op, /* d */ |
435 | &sysrq_term_op, /* e */ | |
436 | &sysrq_moom_op, /* f */ | |
364b5b7b | 437 | /* g: May be registered for the kernel debugger */ |
bf36b901 | 438 | NULL, /* g */ |
c2d75438 | 439 | NULL, /* h - reserved for help */ |
bf36b901 | 440 | &sysrq_kill_op, /* i */ |
c2d75438 ES |
441 | #ifdef CONFIG_BLOCK |
442 | &sysrq_thaw_op, /* j */ | |
443 | #else | |
bf36b901 | 444 | NULL, /* j */ |
c2d75438 | 445 | #endif |
bf36b901 | 446 | &sysrq_SAK_op, /* k */ |
5045bcae RR |
447 | #ifdef CONFIG_SMP |
448 | &sysrq_showallcpus_op, /* l */ | |
449 | #else | |
bf36b901 | 450 | NULL, /* l */ |
5045bcae | 451 | #endif |
bf36b901 AM |
452 | &sysrq_showmem_op, /* m */ |
453 | &sysrq_unrt_op, /* n */ | |
d346cce3 | 454 | /* o: This will often be registered as 'Off' at init time */ |
bf36b901 AM |
455 | NULL, /* o */ |
456 | &sysrq_showregs_op, /* p */ | |
88ad0bf6 | 457 | &sysrq_show_timers_op, /* q */ |
d346cce3 | 458 | &sysrq_unraw_op, /* r */ |
bf36b901 AM |
459 | &sysrq_sync_op, /* s */ |
460 | &sysrq_showstate_op, /* t */ | |
461 | &sysrq_mountro_op, /* u */ | |
364b5b7b | 462 | /* v: May be registered for frame buffer console restore */ |
bf36b901 | 463 | NULL, /* v */ |
d346cce3 | 464 | &sysrq_showstate_blocked_op, /* w */ |
d1e9a4f5 | 465 | /* x: May be registered on mips for TLB dump */ |
d346cce3 | 466 | /* x: May be registered on ppc/powerpc for xmon */ |
916ca14a | 467 | /* x: May be registered on sparc64 for global PMU dump */ |
d346cce3 | 468 | NULL, /* x */ |
93dae5b7 | 469 | /* y: May be registered on sparc64 for global register dump */ |
bf36b901 | 470 | NULL, /* y */ |
69f698ad | 471 | &sysrq_ftrace_dump_op, /* z */ |
1da177e4 LT |
472 | }; |
473 | ||
474 | /* key2index calculation, -1 on invalid index */ | |
bf36b901 AM |
475 | static int sysrq_key_table_key2index(int key) |
476 | { | |
1da177e4 | 477 | int retval; |
bf36b901 AM |
478 | |
479 | if ((key >= '0') && (key <= '9')) | |
1da177e4 | 480 | retval = key - '0'; |
bf36b901 | 481 | else if ((key >= 'a') && (key <= 'z')) |
1da177e4 | 482 | retval = key + 10 - 'a'; |
bf36b901 | 483 | else |
1da177e4 | 484 | retval = -1; |
1da177e4 LT |
485 | return retval; |
486 | } | |
487 | ||
488 | /* | |
489 | * get and put functions for the table, exposed to modules. | |
490 | */ | |
bf36b901 AM |
491 | struct sysrq_key_op *__sysrq_get_key_op(int key) |
492 | { | |
493 | struct sysrq_key_op *op_p = NULL; | |
1da177e4 | 494 | int i; |
bf36b901 | 495 | |
1da177e4 | 496 | i = sysrq_key_table_key2index(key); |
bf36b901 AM |
497 | if (i != -1) |
498 | op_p = sysrq_key_table[i]; | |
97f5f0cd | 499 | |
1da177e4 LT |
500 | return op_p; |
501 | } | |
502 | ||
bf36b901 AM |
503 | static void __sysrq_put_key_op(int key, struct sysrq_key_op *op_p) |
504 | { | |
505 | int i = sysrq_key_table_key2index(key); | |
1da177e4 | 506 | |
1da177e4 LT |
507 | if (i != -1) |
508 | sysrq_key_table[i] = op_p; | |
509 | } | |
510 | ||
f335397d | 511 | void __handle_sysrq(int key, bool check_mask) |
1da177e4 LT |
512 | { |
513 | struct sysrq_key_op *op_p; | |
514 | int orig_log_level; | |
bf36b901 | 515 | int i; |
1da177e4 | 516 | |
722773af | 517 | rcu_sysrq_start(); |
984d74a7 | 518 | rcu_read_lock(); |
fb144adc AW |
519 | /* |
520 | * Raise the apparent loglevel to maximum so that the sysrq header | |
521 | * is shown to provide the user with positive feedback. We do not | |
522 | * simply emit this at KERN_EMERG as that would change message | |
523 | * routing in the consumers of /proc/kmsg. | |
524 | */ | |
1da177e4 | 525 | orig_log_level = console_loglevel; |
a8fe19eb | 526 | console_loglevel = CONSOLE_LOGLEVEL_DEFAULT; |
401e4a7c | 527 | pr_info("SysRq : "); |
1da177e4 LT |
528 | |
529 | op_p = __sysrq_get_key_op(key); | |
530 | if (op_p) { | |
bf36b901 AM |
531 | /* |
532 | * Should we check for enabled operations (/proc/sysrq-trigger | |
533 | * should not) and is the invoked operation enabled? | |
534 | */ | |
5d6f647f | 535 | if (!check_mask || sysrq_on_mask(op_p->enable_mask)) { |
401e4a7c | 536 | pr_cont("%s\n", op_p->action_msg); |
1da177e4 | 537 | console_loglevel = orig_log_level; |
1495cc9d | 538 | op_p->handler(key); |
bf36b901 | 539 | } else { |
401e4a7c | 540 | pr_cont("This sysrq operation is disabled.\n"); |
bf36b901 | 541 | } |
1da177e4 | 542 | } else { |
401e4a7c | 543 | pr_cont("HELP : "); |
1da177e4 | 544 | /* Only print the help msg once per handler */ |
bf36b901 AM |
545 | for (i = 0; i < ARRAY_SIZE(sysrq_key_table); i++) { |
546 | if (sysrq_key_table[i]) { | |
547 | int j; | |
548 | ||
549 | for (j = 0; sysrq_key_table[i] != | |
550 | sysrq_key_table[j]; j++) | |
551 | ; | |
552 | if (j != i) | |
553 | continue; | |
401e4a7c | 554 | pr_cont("%s ", sysrq_key_table[i]->help_msg); |
bf36b901 | 555 | } |
1da177e4 | 556 | } |
401e4a7c | 557 | pr_cont("\n"); |
1da177e4 LT |
558 | console_loglevel = orig_log_level; |
559 | } | |
984d74a7 | 560 | rcu_read_unlock(); |
722773af | 561 | rcu_sysrq_end(); |
1da177e4 LT |
562 | } |
563 | ||
f335397d | 564 | void handle_sysrq(int key) |
1da177e4 | 565 | { |
5d6f647f | 566 | if (sysrq_on()) |
f335397d | 567 | __handle_sysrq(key, true); |
1da177e4 | 568 | } |
bf36b901 | 569 | EXPORT_SYMBOL(handle_sysrq); |
1da177e4 | 570 | |
97f5f0cd | 571 | #ifdef CONFIG_INPUT |
ffb6e0c9 | 572 | static int sysrq_reset_downtime_ms; |
97f5f0cd DT |
573 | |
574 | /* Simple translation table for the SysRq keys */ | |
fcb71930 | 575 | static const unsigned char sysrq_xlate[KEY_CNT] = |
97f5f0cd DT |
576 | "\000\0331234567890-=\177\t" /* 0x00 - 0x0f */ |
577 | "qwertyuiop[]\r\000as" /* 0x10 - 0x1f */ | |
578 | "dfghjkl;'`\000\\zxcv" /* 0x20 - 0x2f */ | |
579 | "bnm,./\000*\000 \000\201\202\203\204\205" /* 0x30 - 0x3f */ | |
580 | "\206\207\210\211\212\000\000789-456+1" /* 0x40 - 0x4f */ | |
581 | "230\177\000\000\213\214\000\000\000\000\000\000\000\000\000\000" /* 0x50 - 0x5f */ | |
582 | "\r\000/"; /* 0x60 - 0x6f */ | |
583 | ||
fcb71930 DT |
584 | struct sysrq_state { |
585 | struct input_handle handle; | |
586 | struct work_struct reinject_work; | |
587 | unsigned long key_down[BITS_TO_LONGS(KEY_CNT)]; | |
588 | unsigned int alt; | |
589 | unsigned int alt_use; | |
590 | bool active; | |
591 | bool need_reinject; | |
7ab7b5ad | 592 | bool reinjecting; |
154b7a48 MP |
593 | |
594 | /* reset sequence handling */ | |
595 | bool reset_canceled; | |
3d289517 | 596 | bool reset_requested; |
154b7a48 MP |
597 | unsigned long reset_keybit[BITS_TO_LONGS(KEY_CNT)]; |
598 | int reset_seq_len; | |
599 | int reset_seq_cnt; | |
600 | int reset_seq_version; | |
39030786 | 601 | struct timer_list keyreset_timer; |
fcb71930 DT |
602 | }; |
603 | ||
154b7a48 MP |
604 | #define SYSRQ_KEY_RESET_MAX 20 /* Should be plenty */ |
605 | static unsigned short sysrq_reset_seq[SYSRQ_KEY_RESET_MAX]; | |
606 | static unsigned int sysrq_reset_seq_len; | |
607 | static unsigned int sysrq_reset_seq_version = 1; | |
608 | ||
609 | static void sysrq_parse_reset_sequence(struct sysrq_state *state) | |
610 | { | |
611 | int i; | |
612 | unsigned short key; | |
613 | ||
614 | state->reset_seq_cnt = 0; | |
615 | ||
616 | for (i = 0; i < sysrq_reset_seq_len; i++) { | |
617 | key = sysrq_reset_seq[i]; | |
618 | ||
619 | if (key == KEY_RESERVED || key > KEY_MAX) | |
620 | break; | |
621 | ||
622 | __set_bit(key, state->reset_keybit); | |
623 | state->reset_seq_len++; | |
624 | ||
625 | if (test_bit(key, state->key_down)) | |
626 | state->reset_seq_cnt++; | |
627 | } | |
628 | ||
629 | /* Disable reset until old keys are not released */ | |
630 | state->reset_canceled = state->reset_seq_cnt != 0; | |
631 | ||
632 | state->reset_seq_version = sysrq_reset_seq_version; | |
633 | } | |
634 | ||
3d289517 | 635 | static void sysrq_do_reset(unsigned long _state) |
39030786 | 636 | { |
3d289517 MP |
637 | struct sysrq_state *state = (struct sysrq_state *) _state; |
638 | ||
639 | state->reset_requested = true; | |
640 | ||
641 | sys_sync(); | |
642 | kernel_restart(NULL); | |
39030786 MP |
643 | } |
644 | ||
645 | static void sysrq_handle_reset_request(struct sysrq_state *state) | |
646 | { | |
3d289517 MP |
647 | if (state->reset_requested) |
648 | __handle_sysrq(sysrq_xlate[KEY_B], false); | |
649 | ||
39030786 MP |
650 | if (sysrq_reset_downtime_ms) |
651 | mod_timer(&state->keyreset_timer, | |
652 | jiffies + msecs_to_jiffies(sysrq_reset_downtime_ms)); | |
653 | else | |
3d289517 | 654 | sysrq_do_reset((unsigned long)state); |
39030786 MP |
655 | } |
656 | ||
657 | static void sysrq_detect_reset_sequence(struct sysrq_state *state, | |
154b7a48 MP |
658 | unsigned int code, int value) |
659 | { | |
660 | if (!test_bit(code, state->reset_keybit)) { | |
661 | /* | |
662 | * Pressing any key _not_ in reset sequence cancels | |
39030786 MP |
663 | * the reset sequence. Also cancelling the timer in |
664 | * case additional keys were pressed after a reset | |
665 | * has been requested. | |
154b7a48 | 666 | */ |
39030786 | 667 | if (value && state->reset_seq_cnt) { |
154b7a48 | 668 | state->reset_canceled = true; |
39030786 MP |
669 | del_timer(&state->keyreset_timer); |
670 | } | |
154b7a48 | 671 | } else if (value == 0) { |
39030786 MP |
672 | /* |
673 | * Key release - all keys in the reset sequence need | |
674 | * to be pressed and held for the reset timeout | |
675 | * to hold. | |
676 | */ | |
677 | del_timer(&state->keyreset_timer); | |
678 | ||
154b7a48 MP |
679 | if (--state->reset_seq_cnt == 0) |
680 | state->reset_canceled = false; | |
681 | } else if (value == 1) { | |
682 | /* key press, not autorepeat */ | |
683 | if (++state->reset_seq_cnt == state->reset_seq_len && | |
684 | !state->reset_canceled) { | |
39030786 | 685 | sysrq_handle_reset_request(state); |
154b7a48 MP |
686 | } |
687 | } | |
154b7a48 MP |
688 | } |
689 | ||
4c076eb0 MP |
690 | #ifdef CONFIG_OF |
691 | static void sysrq_of_get_keyreset_config(void) | |
692 | { | |
693 | u32 key; | |
694 | struct device_node *np; | |
695 | struct property *prop; | |
696 | const __be32 *p; | |
697 | ||
698 | np = of_find_node_by_path("/chosen/linux,sysrq-reset-seq"); | |
699 | if (!np) { | |
700 | pr_debug("No sysrq node found"); | |
701 | return; | |
702 | } | |
703 | ||
704 | /* Reset in case a __weak definition was present */ | |
705 | sysrq_reset_seq_len = 0; | |
706 | ||
707 | of_property_for_each_u32(np, "keyset", prop, p, key) { | |
708 | if (key == KEY_RESERVED || key > KEY_MAX || | |
709 | sysrq_reset_seq_len == SYSRQ_KEY_RESET_MAX) | |
710 | break; | |
711 | ||
712 | sysrq_reset_seq[sysrq_reset_seq_len++] = (unsigned short)key; | |
713 | } | |
714 | ||
715 | /* Get reset timeout if any. */ | |
716 | of_property_read_u32(np, "timeout-ms", &sysrq_reset_downtime_ms); | |
717 | } | |
718 | #else | |
719 | static void sysrq_of_get_keyreset_config(void) | |
720 | { | |
721 | } | |
722 | #endif | |
723 | ||
fcb71930 DT |
724 | static void sysrq_reinject_alt_sysrq(struct work_struct *work) |
725 | { | |
726 | struct sysrq_state *sysrq = | |
727 | container_of(work, struct sysrq_state, reinject_work); | |
728 | struct input_handle *handle = &sysrq->handle; | |
729 | unsigned int alt_code = sysrq->alt_use; | |
730 | ||
731 | if (sysrq->need_reinject) { | |
7ab7b5ad DT |
732 | /* we do not want the assignment to be reordered */ |
733 | sysrq->reinjecting = true; | |
734 | mb(); | |
735 | ||
fcb71930 DT |
736 | /* Simulate press and release of Alt + SysRq */ |
737 | input_inject_event(handle, EV_KEY, alt_code, 1); | |
738 | input_inject_event(handle, EV_KEY, KEY_SYSRQ, 1); | |
739 | input_inject_event(handle, EV_SYN, SYN_REPORT, 1); | |
740 | ||
741 | input_inject_event(handle, EV_KEY, KEY_SYSRQ, 0); | |
742 | input_inject_event(handle, EV_KEY, alt_code, 0); | |
743 | input_inject_event(handle, EV_SYN, SYN_REPORT, 1); | |
7ab7b5ad DT |
744 | |
745 | mb(); | |
746 | sysrq->reinjecting = false; | |
fcb71930 DT |
747 | } |
748 | } | |
97f5f0cd | 749 | |
154b7a48 MP |
750 | static bool sysrq_handle_keypress(struct sysrq_state *sysrq, |
751 | unsigned int code, int value) | |
97f5f0cd | 752 | { |
fcb71930 | 753 | bool was_active = sysrq->active; |
1966cb22 DT |
754 | bool suppress; |
755 | ||
154b7a48 | 756 | switch (code) { |
7ab7b5ad | 757 | |
154b7a48 MP |
758 | case KEY_LEFTALT: |
759 | case KEY_RIGHTALT: | |
760 | if (!value) { | |
761 | /* One of ALTs is being released */ | |
762 | if (sysrq->active && code == sysrq->alt_use) | |
763 | sysrq->active = false; | |
1966cb22 | 764 | |
154b7a48 MP |
765 | sysrq->alt = KEY_RESERVED; |
766 | ||
767 | } else if (value != 2) { | |
768 | sysrq->alt = code; | |
769 | sysrq->need_reinject = false; | |
770 | } | |
fcb71930 | 771 | break; |
97f5f0cd | 772 | |
154b7a48 MP |
773 | case KEY_SYSRQ: |
774 | if (value == 1 && sysrq->alt != KEY_RESERVED) { | |
775 | sysrq->active = true; | |
776 | sysrq->alt_use = sysrq->alt; | |
777 | /* | |
778 | * If nothing else will be pressed we'll need | |
779 | * to re-inject Alt-SysRq keysroke. | |
780 | */ | |
781 | sysrq->need_reinject = true; | |
782 | } | |
97f5f0cd | 783 | |
154b7a48 MP |
784 | /* |
785 | * Pretend that sysrq was never pressed at all. This | |
786 | * is needed to properly handle KGDB which will try | |
787 | * to release all keys after exiting debugger. If we | |
788 | * do not clear key bit it KGDB will end up sending | |
789 | * release events for Alt and SysRq, potentially | |
790 | * triggering print screen function. | |
791 | */ | |
792 | if (sysrq->active) | |
793 | clear_bit(KEY_SYSRQ, sysrq->handle.dev->key); | |
f5dec511 | 794 | |
154b7a48 | 795 | break; |
fcb71930 | 796 | |
154b7a48 MP |
797 | default: |
798 | if (sysrq->active && value && value != 2) { | |
799 | sysrq->need_reinject = false; | |
800 | __handle_sysrq(sysrq_xlate[code], true); | |
801 | } | |
802 | break; | |
803 | } | |
fcb71930 | 804 | |
154b7a48 | 805 | suppress = sysrq->active; |
fcb71930 | 806 | |
154b7a48 | 807 | if (!sysrq->active) { |
fcb71930 | 808 | |
154b7a48 MP |
809 | /* |
810 | * See if reset sequence has changed since the last time. | |
811 | */ | |
812 | if (sysrq->reset_seq_version != sysrq_reset_seq_version) | |
813 | sysrq_parse_reset_sequence(sysrq); | |
fcb71930 | 814 | |
154b7a48 MP |
815 | /* |
816 | * If we are not suppressing key presses keep track of | |
817 | * keyboard state so we can release keys that have been | |
818 | * pressed before entering SysRq mode. | |
819 | */ | |
820 | if (value) | |
821 | set_bit(code, sysrq->key_down); | |
822 | else | |
823 | clear_bit(code, sysrq->key_down); | |
824 | ||
825 | if (was_active) | |
826 | schedule_work(&sysrq->reinject_work); | |
827 | ||
39030786 MP |
828 | /* Check for reset sequence */ |
829 | sysrq_detect_reset_sequence(sysrq, code, value); | |
97f5f0cd | 830 | |
154b7a48 MP |
831 | } else if (value == 0 && test_and_clear_bit(code, sysrq->key_down)) { |
832 | /* | |
833 | * Pass on release events for keys that was pressed before | |
834 | * entering SysRq mode. | |
835 | */ | |
836 | suppress = false; | |
837 | } | |
fcb71930 | 838 | |
154b7a48 MP |
839 | return suppress; |
840 | } | |
fcb71930 | 841 | |
154b7a48 MP |
842 | static bool sysrq_filter(struct input_handle *handle, |
843 | unsigned int type, unsigned int code, int value) | |
844 | { | |
845 | struct sysrq_state *sysrq = handle->private; | |
846 | bool suppress; | |
fcb71930 | 847 | |
154b7a48 MP |
848 | /* |
849 | * Do not filter anything if we are in the process of re-injecting | |
850 | * Alt+SysRq combination. | |
851 | */ | |
852 | if (sysrq->reinjecting) | |
853 | return false; | |
854 | ||
855 | switch (type) { | |
856 | ||
857 | case EV_SYN: | |
858 | suppress = false; | |
859 | break; | |
860 | ||
861 | case EV_KEY: | |
862 | suppress = sysrq_handle_keypress(sysrq, code, value); | |
97f5f0cd DT |
863 | break; |
864 | ||
865 | default: | |
fcb71930 | 866 | suppress = sysrq->active; |
97f5f0cd DT |
867 | break; |
868 | } | |
869 | ||
1966cb22 | 870 | return suppress; |
97f5f0cd DT |
871 | } |
872 | ||
873 | static int sysrq_connect(struct input_handler *handler, | |
874 | struct input_dev *dev, | |
875 | const struct input_device_id *id) | |
876 | { | |
fcb71930 | 877 | struct sysrq_state *sysrq; |
97f5f0cd DT |
878 | int error; |
879 | ||
fcb71930 DT |
880 | sysrq = kzalloc(sizeof(struct sysrq_state), GFP_KERNEL); |
881 | if (!sysrq) | |
97f5f0cd DT |
882 | return -ENOMEM; |
883 | ||
fcb71930 DT |
884 | INIT_WORK(&sysrq->reinject_work, sysrq_reinject_alt_sysrq); |
885 | ||
886 | sysrq->handle.dev = dev; | |
887 | sysrq->handle.handler = handler; | |
888 | sysrq->handle.name = "sysrq"; | |
889 | sysrq->handle.private = sysrq; | |
3d289517 MP |
890 | setup_timer(&sysrq->keyreset_timer, |
891 | sysrq_do_reset, (unsigned long)sysrq); | |
97f5f0cd | 892 | |
fcb71930 | 893 | error = input_register_handle(&sysrq->handle); |
97f5f0cd DT |
894 | if (error) { |
895 | pr_err("Failed to register input sysrq handler, error %d\n", | |
896 | error); | |
897 | goto err_free; | |
898 | } | |
899 | ||
fcb71930 | 900 | error = input_open_device(&sysrq->handle); |
97f5f0cd DT |
901 | if (error) { |
902 | pr_err("Failed to open input device, error %d\n", error); | |
903 | goto err_unregister; | |
904 | } | |
905 | ||
906 | return 0; | |
907 | ||
908 | err_unregister: | |
fcb71930 | 909 | input_unregister_handle(&sysrq->handle); |
97f5f0cd | 910 | err_free: |
fcb71930 | 911 | kfree(sysrq); |
97f5f0cd DT |
912 | return error; |
913 | } | |
914 | ||
915 | static void sysrq_disconnect(struct input_handle *handle) | |
916 | { | |
fcb71930 DT |
917 | struct sysrq_state *sysrq = handle->private; |
918 | ||
97f5f0cd | 919 | input_close_device(handle); |
fcb71930 | 920 | cancel_work_sync(&sysrq->reinject_work); |
39030786 | 921 | del_timer_sync(&sysrq->keyreset_timer); |
97f5f0cd | 922 | input_unregister_handle(handle); |
fcb71930 | 923 | kfree(sysrq); |
97f5f0cd DT |
924 | } |
925 | ||
926 | /* | |
1966cb22 DT |
927 | * We are matching on KEY_LEFTALT instead of KEY_SYSRQ because not all |
928 | * keyboards have SysRq key predefined and so user may add it to keymap | |
97f5f0cd DT |
929 | * later, but we expect all such keyboards to have left alt. |
930 | */ | |
931 | static const struct input_device_id sysrq_ids[] = { | |
932 | { | |
933 | .flags = INPUT_DEVICE_ID_MATCH_EVBIT | | |
934 | INPUT_DEVICE_ID_MATCH_KEYBIT, | |
935 | .evbit = { BIT_MASK(EV_KEY) }, | |
936 | .keybit = { BIT_MASK(KEY_LEFTALT) }, | |
937 | }, | |
938 | { }, | |
939 | }; | |
940 | ||
941 | static struct input_handler sysrq_handler = { | |
942 | .filter = sysrq_filter, | |
943 | .connect = sysrq_connect, | |
944 | .disconnect = sysrq_disconnect, | |
945 | .name = "sysrq", | |
946 | .id_table = sysrq_ids, | |
947 | }; | |
948 | ||
949 | static bool sysrq_handler_registered; | |
950 | ||
951 | static inline void sysrq_register_handler(void) | |
952 | { | |
953 | int error; | |
954 | ||
4c076eb0 MP |
955 | sysrq_of_get_keyreset_config(); |
956 | ||
97f5f0cd DT |
957 | error = input_register_handler(&sysrq_handler); |
958 | if (error) | |
959 | pr_err("Failed to register input handler, error %d", error); | |
960 | else | |
961 | sysrq_handler_registered = true; | |
962 | } | |
963 | ||
964 | static inline void sysrq_unregister_handler(void) | |
965 | { | |
966 | if (sysrq_handler_registered) { | |
967 | input_unregister_handler(&sysrq_handler); | |
968 | sysrq_handler_registered = false; | |
969 | } | |
970 | } | |
971 | ||
154b7a48 MP |
972 | static int sysrq_reset_seq_param_set(const char *buffer, |
973 | const struct kernel_param *kp) | |
974 | { | |
975 | unsigned long val; | |
976 | int error; | |
977 | ||
86b40567 | 978 | error = kstrtoul(buffer, 0, &val); |
154b7a48 MP |
979 | if (error < 0) |
980 | return error; | |
981 | ||
982 | if (val > KEY_MAX) | |
983 | return -EINVAL; | |
984 | ||
985 | *((unsigned short *)kp->arg) = val; | |
986 | sysrq_reset_seq_version++; | |
987 | ||
988 | return 0; | |
989 | } | |
990 | ||
9c27847d | 991 | static const struct kernel_param_ops param_ops_sysrq_reset_seq = { |
154b7a48 MP |
992 | .get = param_get_ushort, |
993 | .set = sysrq_reset_seq_param_set, | |
994 | }; | |
995 | ||
996 | #define param_check_sysrq_reset_seq(name, p) \ | |
997 | __param_check(name, p, unsigned short) | |
998 | ||
999 | module_param_array_named(reset_seq, sysrq_reset_seq, sysrq_reset_seq, | |
1000 | &sysrq_reset_seq_len, 0644); | |
1001 | ||
39030786 MP |
1002 | module_param_named(sysrq_downtime_ms, sysrq_reset_downtime_ms, int, 0644); |
1003 | ||
97f5f0cd DT |
1004 | #else |
1005 | ||
1006 | static inline void sysrq_register_handler(void) | |
1007 | { | |
1008 | } | |
1009 | ||
1010 | static inline void sysrq_unregister_handler(void) | |
1011 | { | |
1012 | } | |
1013 | ||
1014 | #endif /* CONFIG_INPUT */ | |
1015 | ||
1016 | int sysrq_toggle_support(int enable_mask) | |
1017 | { | |
1018 | bool was_enabled = sysrq_on(); | |
1019 | ||
1020 | sysrq_enabled = enable_mask; | |
1021 | ||
1022 | if (was_enabled != sysrq_on()) { | |
1023 | if (sysrq_on()) | |
1024 | sysrq_register_handler(); | |
1025 | else | |
1026 | sysrq_unregister_handler(); | |
1027 | } | |
1028 | ||
1029 | return 0; | |
1030 | } | |
1031 | ||
cf62ddce | 1032 | static int __sysrq_swap_key_ops(int key, struct sysrq_key_op *insert_op_p, |
bf36b901 AM |
1033 | struct sysrq_key_op *remove_op_p) |
1034 | { | |
1da177e4 | 1035 | int retval; |
1da177e4 | 1036 | |
984d74a7 | 1037 | spin_lock(&sysrq_key_table_lock); |
1da177e4 LT |
1038 | if (__sysrq_get_key_op(key) == remove_op_p) { |
1039 | __sysrq_put_key_op(key, insert_op_p); | |
1040 | retval = 0; | |
1041 | } else { | |
1042 | retval = -1; | |
1043 | } | |
984d74a7 RR |
1044 | spin_unlock(&sysrq_key_table_lock); |
1045 | ||
1046 | /* | |
1047 | * A concurrent __handle_sysrq either got the old op or the new op. | |
1048 | * Wait for it to go away before returning, so the code for an old | |
1049 | * op is not freed (eg. on module unload) while it is in use. | |
1050 | */ | |
1051 | synchronize_rcu(); | |
1052 | ||
1da177e4 LT |
1053 | return retval; |
1054 | } | |
1055 | ||
1056 | int register_sysrq_key(int key, struct sysrq_key_op *op_p) | |
1057 | { | |
1058 | return __sysrq_swap_key_ops(key, op_p, NULL); | |
1059 | } | |
bf36b901 | 1060 | EXPORT_SYMBOL(register_sysrq_key); |
1da177e4 LT |
1061 | |
1062 | int unregister_sysrq_key(int key, struct sysrq_key_op *op_p) | |
1063 | { | |
1064 | return __sysrq_swap_key_ops(key, NULL, op_p); | |
1065 | } | |
1da177e4 | 1066 | EXPORT_SYMBOL(unregister_sysrq_key); |
f40cbaa5 AD |
1067 | |
1068 | #ifdef CONFIG_PROC_FS | |
1069 | /* | |
1070 | * writing 'C' to /proc/sysrq-trigger is like sysrq-C | |
1071 | */ | |
1072 | static ssize_t write_sysrq_trigger(struct file *file, const char __user *buf, | |
1073 | size_t count, loff_t *ppos) | |
1074 | { | |
1075 | if (count) { | |
1076 | char c; | |
1077 | ||
1078 | if (get_user(c, buf)) | |
1079 | return -EFAULT; | |
f335397d | 1080 | __handle_sysrq(c, false); |
f40cbaa5 | 1081 | } |
97f5f0cd | 1082 | |
f40cbaa5 AD |
1083 | return count; |
1084 | } | |
1085 | ||
1086 | static const struct file_operations proc_sysrq_trigger_operations = { | |
1087 | .write = write_sysrq_trigger, | |
6038f373 | 1088 | .llseek = noop_llseek, |
f40cbaa5 AD |
1089 | }; |
1090 | ||
97f5f0cd DT |
1091 | static void sysrq_init_procfs(void) |
1092 | { | |
1093 | if (!proc_create("sysrq-trigger", S_IWUSR, NULL, | |
1094 | &proc_sysrq_trigger_operations)) | |
1095 | pr_err("Failed to register proc interface\n"); | |
1096 | } | |
1097 | ||
1098 | #else | |
1099 | ||
1100 | static inline void sysrq_init_procfs(void) | |
1101 | { | |
1102 | } | |
1103 | ||
1104 | #endif /* CONFIG_PROC_FS */ | |
1105 | ||
f40cbaa5 AD |
1106 | static int __init sysrq_init(void) |
1107 | { | |
97f5f0cd DT |
1108 | sysrq_init_procfs(); |
1109 | ||
1110 | if (sysrq_on()) | |
1111 | sysrq_register_handler(); | |
1112 | ||
f40cbaa5 AD |
1113 | return 0; |
1114 | } | |
1115 | module_init(sysrq_init); |