Commit | Line | Data |
---|---|---|
b2441318 | 1 | // SPDX-License-Identifier: GPL-2.0 |
97f5f0cd | 2 | /* |
1da177e4 LT |
3 | * Linux Magic System Request Key Hacks |
4 | * | |
5 | * (c) 1997 Martin Mares <mj@atrey.karlin.mff.cuni.cz> | |
6 | * based on ideas by Pavel Machek <pavel@atrey.karlin.mff.cuni.cz> | |
7 | * | |
8 | * (c) 2000 Crutcher Dunnavant <crutcher+kernel@datastacks.com> | |
9 | * overhauled to use key registration | |
10 | * based upon discusions in irc://irc.openprojects.net/#kernelnewbies | |
97f5f0cd DT |
11 | * |
12 | * Copyright (c) 2010 Dmitry Torokhov | |
13 | * Input handler conversion | |
1da177e4 LT |
14 | */ |
15 | ||
97f5f0cd DT |
16 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
17 | ||
3f07c014 | 18 | #include <linux/sched/signal.h> |
8bd75c77 | 19 | #include <linux/sched/rt.h> |
b17b0153 | 20 | #include <linux/sched/debug.h> |
29930025 | 21 | #include <linux/sched/task.h> |
a27eb0cb | 22 | #include <linux/ctype.h> |
1da177e4 LT |
23 | #include <linux/interrupt.h> |
24 | #include <linux/mm.h> | |
25 | #include <linux/fs.h> | |
1da177e4 LT |
26 | #include <linux/mount.h> |
27 | #include <linux/kdev_t.h> | |
28 | #include <linux/major.h> | |
29 | #include <linux/reboot.h> | |
30 | #include <linux/sysrq.h> | |
31 | #include <linux/kbd_kern.h> | |
f40cbaa5 | 32 | #include <linux/proc_fs.h> |
c1dc0b9c | 33 | #include <linux/nmi.h> |
1da177e4 | 34 | #include <linux/quotaops.h> |
cdd6c482 | 35 | #include <linux/perf_event.h> |
1da177e4 LT |
36 | #include <linux/kernel.h> |
37 | #include <linux/module.h> | |
38 | #include <linux/suspend.h> | |
39 | #include <linux/writeback.h> | |
1da177e4 LT |
40 | #include <linux/swap.h> |
41 | #include <linux/spinlock.h> | |
42 | #include <linux/vt_kern.h> | |
43 | #include <linux/workqueue.h> | |
88ad0bf6 | 44 | #include <linux/hrtimer.h> |
5a3135c2 | 45 | #include <linux/oom.h> |
5a0e3ad6 | 46 | #include <linux/slab.h> |
97f5f0cd | 47 | #include <linux/input.h> |
ff01bb48 | 48 | #include <linux/uaccess.h> |
154b7a48 | 49 | #include <linux/moduleparam.h> |
39030786 | 50 | #include <linux/jiffies.h> |
3d289517 | 51 | #include <linux/syscalls.h> |
4c076eb0 | 52 | #include <linux/of.h> |
722773af | 53 | #include <linux/rcupdate.h> |
1da177e4 LT |
54 | |
55 | #include <asm/ptrace.h> | |
2033b0c3 | 56 | #include <asm/irq_regs.h> |
1da177e4 LT |
57 | |
58 | /* Whether we react on sysrq keys or just ignore them */ | |
8eaede49 | 59 | static int __read_mostly sysrq_enabled = CONFIG_MAGIC_SYSRQ_DEFAULT_ENABLE; |
97f5f0cd | 60 | static bool __read_mostly sysrq_always_enabled; |
5d6f647f | 61 | |
97f5f0cd | 62 | static bool sysrq_on(void) |
5d6f647f | 63 | { |
97f5f0cd | 64 | return sysrq_enabled || sysrq_always_enabled; |
5d6f647f IM |
65 | } |
66 | ||
eaee4172 DS |
67 | /** |
68 | * sysrq_mask - Getter for sysrq_enabled mask. | |
69 | * | |
70 | * Return: 1 if sysrq is always enabled, enabled sysrq_key_op mask otherwise. | |
71 | */ | |
72 | int sysrq_mask(void) | |
73 | { | |
74 | if (sysrq_always_enabled) | |
75 | return 1; | |
76 | return sysrq_enabled; | |
77 | } | |
66bb1c95 | 78 | EXPORT_SYMBOL_GPL(sysrq_mask); |
eaee4172 | 79 | |
5d6f647f IM |
80 | /* |
81 | * A value of 1 means 'all', other nonzero values are an op mask: | |
82 | */ | |
97f5f0cd | 83 | static bool sysrq_on_mask(int mask) |
5d6f647f | 84 | { |
97f5f0cd DT |
85 | return sysrq_always_enabled || |
86 | sysrq_enabled == 1 || | |
87 | (sysrq_enabled & mask); | |
5d6f647f IM |
88 | } |
89 | ||
90 | static int __init sysrq_always_enabled_setup(char *str) | |
91 | { | |
97f5f0cd DT |
92 | sysrq_always_enabled = true; |
93 | pr_info("sysrq always enabled.\n"); | |
5d6f647f IM |
94 | |
95 | return 1; | |
96 | } | |
97 | ||
98 | __setup("sysrq_always_enabled", sysrq_always_enabled_setup); | |
99 | ||
1da177e4 | 100 | |
1495cc9d | 101 | static void sysrq_handle_loglevel(int key) |
1da177e4 LT |
102 | { |
103 | int i; | |
97f5f0cd | 104 | |
1da177e4 | 105 | i = key - '0'; |
a8fe19eb | 106 | console_loglevel = CONSOLE_LOGLEVEL_DEFAULT; |
401e4a7c | 107 | pr_info("Loglevel set to %d\n", i); |
1da177e4 | 108 | console_loglevel = i; |
bf36b901 | 109 | } |
7fffe31d | 110 | static const struct sysrq_key_op sysrq_loglevel_op = { |
1da177e4 | 111 | .handler = sysrq_handle_loglevel, |
208b95ce | 112 | .help_msg = "loglevel(0-9)", |
1da177e4 LT |
113 | .action_msg = "Changing Loglevel", |
114 | .enable_mask = SYSRQ_ENABLE_LOG, | |
115 | }; | |
116 | ||
1da177e4 | 117 | #ifdef CONFIG_VT |
1495cc9d | 118 | static void sysrq_handle_SAK(int key) |
1da177e4 | 119 | { |
8b6312f4 | 120 | struct work_struct *SAK_work = &vc_cons[fg_console].SAK_work; |
2c4a4cde | 121 | |
8b6312f4 | 122 | schedule_work(SAK_work); |
1da177e4 | 123 | } |
7fffe31d | 124 | static const struct sysrq_key_op sysrq_SAK_op = { |
1da177e4 | 125 | .handler = sysrq_handle_SAK, |
afa80ccb | 126 | .help_msg = "sak(k)", |
1da177e4 LT |
127 | .action_msg = "SAK", |
128 | .enable_mask = SYSRQ_ENABLE_KEYBOARD, | |
129 | }; | |
bf36b901 | 130 | #else |
7fffe31d | 131 | #define sysrq_SAK_op (*(const struct sysrq_key_op *)NULL) |
1da177e4 LT |
132 | #endif |
133 | ||
134 | #ifdef CONFIG_VT | |
1495cc9d | 135 | static void sysrq_handle_unraw(int key) |
1da177e4 | 136 | { |
079c9534 | 137 | vt_reset_unicode(fg_console); |
1da177e4 | 138 | } |
079c9534 | 139 | |
7fffe31d | 140 | static const struct sysrq_key_op sysrq_unraw_op = { |
1da177e4 | 141 | .handler = sysrq_handle_unraw, |
afa80ccb | 142 | .help_msg = "unraw(r)", |
2e8ecb9d | 143 | .action_msg = "Keyboard mode set to system default", |
1da177e4 LT |
144 | .enable_mask = SYSRQ_ENABLE_KEYBOARD, |
145 | }; | |
bf36b901 | 146 | #else |
7fffe31d | 147 | #define sysrq_unraw_op (*(const struct sysrq_key_op *)NULL) |
1da177e4 LT |
148 | #endif /* CONFIG_VT */ |
149 | ||
1495cc9d | 150 | static void sysrq_handle_crash(int key) |
86b1ae38 | 151 | { |
8341f2f2 | 152 | /* release the RCU read lock before crashing */ |
984cf355 | 153 | rcu_read_unlock(); |
8341f2f2 MK |
154 | |
155 | panic("sysrq triggered crash\n"); | |
86b1ae38 | 156 | } |
7fffe31d | 157 | static const struct sysrq_key_op sysrq_crash_op = { |
d6580a9f | 158 | .handler = sysrq_handle_crash, |
afa80ccb | 159 | .help_msg = "crash(c)", |
d6580a9f | 160 | .action_msg = "Trigger a crash", |
86b1ae38 HN |
161 | .enable_mask = SYSRQ_ENABLE_DUMP, |
162 | }; | |
86b1ae38 | 163 | |
1495cc9d | 164 | static void sysrq_handle_reboot(int key) |
1da177e4 | 165 | { |
b2e9c7d0 | 166 | lockdep_off(); |
1da177e4 | 167 | local_irq_enable(); |
4de8b9b7 | 168 | emergency_restart(); |
1da177e4 | 169 | } |
7fffe31d | 170 | static const struct sysrq_key_op sysrq_reboot_op = { |
1da177e4 | 171 | .handler = sysrq_handle_reboot, |
afa80ccb | 172 | .help_msg = "reboot(b)", |
1da177e4 LT |
173 | .action_msg = "Resetting", |
174 | .enable_mask = SYSRQ_ENABLE_BOOT, | |
175 | }; | |
176 | ||
7fffe31d | 177 | const struct sysrq_key_op *__sysrq_reboot_op = &sysrq_reboot_op; |
0f1c9688 | 178 | |
1495cc9d | 179 | static void sysrq_handle_sync(int key) |
1da177e4 LT |
180 | { |
181 | emergency_sync(); | |
182 | } | |
7fffe31d | 183 | static const struct sysrq_key_op sysrq_sync_op = { |
1da177e4 | 184 | .handler = sysrq_handle_sync, |
afa80ccb | 185 | .help_msg = "sync(s)", |
1da177e4 LT |
186 | .action_msg = "Emergency Sync", |
187 | .enable_mask = SYSRQ_ENABLE_SYNC, | |
188 | }; | |
189 | ||
1495cc9d | 190 | static void sysrq_handle_show_timers(int key) |
88ad0bf6 IM |
191 | { |
192 | sysrq_timer_list_show(); | |
193 | } | |
194 | ||
7fffe31d | 195 | static const struct sysrq_key_op sysrq_show_timers_op = { |
88ad0bf6 | 196 | .handler = sysrq_handle_show_timers, |
afa80ccb | 197 | .help_msg = "show-all-timers(q)", |
322acf65 | 198 | .action_msg = "Show clockevent devices & pending hrtimers (no others)", |
88ad0bf6 IM |
199 | }; |
200 | ||
1495cc9d | 201 | static void sysrq_handle_mountro(int key) |
1da177e4 LT |
202 | { |
203 | emergency_remount(); | |
204 | } | |
7fffe31d | 205 | static const struct sysrq_key_op sysrq_mountro_op = { |
1da177e4 | 206 | .handler = sysrq_handle_mountro, |
afa80ccb | 207 | .help_msg = "unmount(u)", |
1da177e4 LT |
208 | .action_msg = "Emergency Remount R/O", |
209 | .enable_mask = SYSRQ_ENABLE_REMOUNT, | |
210 | }; | |
211 | ||
8c64580d | 212 | #ifdef CONFIG_LOCKDEP |
1495cc9d | 213 | static void sysrq_handle_showlocks(int key) |
de5097c2 | 214 | { |
9a11b49a | 215 | debug_show_all_locks(); |
de5097c2 | 216 | } |
8c64580d | 217 | |
7fffe31d | 218 | static const struct sysrq_key_op sysrq_showlocks_op = { |
de5097c2 | 219 | .handler = sysrq_handle_showlocks, |
afa80ccb | 220 | .help_msg = "show-all-locks(d)", |
de5097c2 IM |
221 | .action_msg = "Show Locks Held", |
222 | }; | |
bf36b901 | 223 | #else |
7fffe31d | 224 | #define sysrq_showlocks_op (*(const struct sysrq_key_op *)NULL) |
de5097c2 | 225 | #endif |
1da177e4 | 226 | |
5045bcae | 227 | #ifdef CONFIG_SMP |
6ac972dd | 228 | static DEFINE_RAW_SPINLOCK(show_lock); |
5045bcae RR |
229 | |
230 | static void showacpu(void *dummy) | |
231 | { | |
232 | unsigned long flags; | |
233 | ||
234 | /* Idle CPUs have no interesting backtrace. */ | |
5390e7f4 CD |
235 | if (idle_cpu(smp_processor_id())) { |
236 | pr_info("CPU%d: backtrace skipped as idling\n", smp_processor_id()); | |
5045bcae | 237 | return; |
5390e7f4 | 238 | } |
5045bcae | 239 | |
6ac972dd | 240 | raw_spin_lock_irqsave(&show_lock, flags); |
401e4a7c | 241 | pr_info("CPU%d:\n", smp_processor_id()); |
9cb8f069 | 242 | show_stack(NULL, NULL, KERN_INFO); |
6ac972dd | 243 | raw_spin_unlock_irqrestore(&show_lock, flags); |
5045bcae RR |
244 | } |
245 | ||
246 | static void sysrq_showregs_othercpus(struct work_struct *dummy) | |
247 | { | |
8b604d52 | 248 | smp_call_function(showacpu, NULL, 0); |
5045bcae RR |
249 | } |
250 | ||
251 | static DECLARE_WORK(sysrq_showallcpus, sysrq_showregs_othercpus); | |
252 | ||
1495cc9d | 253 | static void sysrq_handle_showallcpus(int key) |
5045bcae | 254 | { |
47cab6a7 IM |
255 | /* |
256 | * Fall back to the workqueue based printing if the | |
257 | * backtrace printing did not succeed or the | |
258 | * architecture has no support for it: | |
259 | */ | |
260 | if (!trigger_all_cpu_backtrace()) { | |
b00bebbc | 261 | struct pt_regs *regs = NULL; |
47cab6a7 | 262 | |
1143637f | 263 | if (in_hardirq()) |
b00bebbc | 264 | regs = get_irq_regs(); |
5390e7f4 CD |
265 | |
266 | pr_info("CPU%d:\n", smp_processor_id()); | |
267 | if (regs) | |
47cab6a7 | 268 | show_regs(regs); |
5390e7f4 CD |
269 | else |
270 | show_stack(NULL, NULL, KERN_INFO); | |
271 | ||
47cab6a7 IM |
272 | schedule_work(&sysrq_showallcpus); |
273 | } | |
5045bcae RR |
274 | } |
275 | ||
7fffe31d | 276 | static const struct sysrq_key_op sysrq_showallcpus_op = { |
5045bcae | 277 | .handler = sysrq_handle_showallcpus, |
afa80ccb | 278 | .help_msg = "show-backtrace-all-active-cpus(l)", |
5045bcae RR |
279 | .action_msg = "Show backtrace of all active CPUs", |
280 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
281 | }; | |
8ec8719f JW |
282 | #else |
283 | #define sysrq_showallcpus_op (*(const struct sysrq_key_op *)NULL) | |
5045bcae RR |
284 | #endif |
285 | ||
1495cc9d | 286 | static void sysrq_handle_showregs(int key) |
1da177e4 | 287 | { |
b00bebbc JX |
288 | struct pt_regs *regs = NULL; |
289 | ||
1143637f | 290 | if (in_hardirq()) |
b00bebbc | 291 | regs = get_irq_regs(); |
7d12e780 DH |
292 | if (regs) |
293 | show_regs(regs); | |
cdd6c482 | 294 | perf_event_print_debug(); |
1da177e4 | 295 | } |
7fffe31d | 296 | static const struct sysrq_key_op sysrq_showregs_op = { |
1da177e4 | 297 | .handler = sysrq_handle_showregs, |
afa80ccb | 298 | .help_msg = "show-registers(p)", |
1da177e4 LT |
299 | .action_msg = "Show Regs", |
300 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
301 | }; | |
302 | ||
1495cc9d | 303 | static void sysrq_handle_showstate(int key) |
1da177e4 LT |
304 | { |
305 | show_state(); | |
55df0933 | 306 | show_all_workqueues(); |
1da177e4 | 307 | } |
7fffe31d | 308 | static const struct sysrq_key_op sysrq_showstate_op = { |
1da177e4 | 309 | .handler = sysrq_handle_showstate, |
afa80ccb | 310 | .help_msg = "show-task-states(t)", |
1da177e4 LT |
311 | .action_msg = "Show State", |
312 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
313 | }; | |
314 | ||
1495cc9d | 315 | static void sysrq_handle_showstate_blocked(int key) |
e59e2ae2 IM |
316 | { |
317 | show_state_filter(TASK_UNINTERRUPTIBLE); | |
318 | } | |
7fffe31d | 319 | static const struct sysrq_key_op sysrq_showstate_blocked_op = { |
e59e2ae2 | 320 | .handler = sysrq_handle_showstate_blocked, |
afa80ccb | 321 | .help_msg = "show-blocked-tasks(w)", |
e59e2ae2 IM |
322 | .action_msg = "Show Blocked State", |
323 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
324 | }; | |
325 | ||
69f698ad PZ |
326 | #ifdef CONFIG_TRACING |
327 | #include <linux/ftrace.h> | |
328 | ||
1495cc9d | 329 | static void sysrq_ftrace_dump(int key) |
69f698ad | 330 | { |
cecbca96 | 331 | ftrace_dump(DUMP_ALL); |
69f698ad | 332 | } |
7fffe31d | 333 | static const struct sysrq_key_op sysrq_ftrace_dump_op = { |
69f698ad | 334 | .handler = sysrq_ftrace_dump, |
afa80ccb | 335 | .help_msg = "dump-ftrace-buffer(z)", |
69f698ad PZ |
336 | .action_msg = "Dump ftrace buffer", |
337 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
338 | }; | |
339 | #else | |
7fffe31d | 340 | #define sysrq_ftrace_dump_op (*(const struct sysrq_key_op *)NULL) |
69f698ad | 341 | #endif |
e59e2ae2 | 342 | |
1495cc9d | 343 | static void sysrq_handle_showmem(int key) |
1da177e4 | 344 | { |
9af744d7 | 345 | show_mem(0, NULL); |
1da177e4 | 346 | } |
7fffe31d | 347 | static const struct sysrq_key_op sysrq_showmem_op = { |
1da177e4 | 348 | .handler = sysrq_handle_showmem, |
afa80ccb | 349 | .help_msg = "show-memory-usage(m)", |
1da177e4 LT |
350 | .action_msg = "Show Memory", |
351 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
352 | }; | |
353 | ||
bf36b901 AM |
354 | /* |
355 | * Signal sysrq helper function. Sends a signal to all user processes. | |
356 | */ | |
1da177e4 LT |
357 | static void send_sig_all(int sig) |
358 | { | |
359 | struct task_struct *p; | |
360 | ||
e502babe | 361 | read_lock(&tasklist_lock); |
1da177e4 | 362 | for_each_process(p) { |
d3a532a9 AV |
363 | if (p->flags & PF_KTHREAD) |
364 | continue; | |
365 | if (is_global_init(p)) | |
366 | continue; | |
367 | ||
b16503ba | 368 | do_send_sig_info(sig, SEND_SIG_PRIV, p, PIDTYPE_MAX); |
1da177e4 | 369 | } |
e502babe | 370 | read_unlock(&tasklist_lock); |
1da177e4 LT |
371 | } |
372 | ||
1495cc9d | 373 | static void sysrq_handle_term(int key) |
1da177e4 LT |
374 | { |
375 | send_sig_all(SIGTERM); | |
a8fe19eb | 376 | console_loglevel = CONSOLE_LOGLEVEL_DEBUG; |
1da177e4 | 377 | } |
7fffe31d | 378 | static const struct sysrq_key_op sysrq_term_op = { |
1da177e4 | 379 | .handler = sysrq_handle_term, |
afa80ccb | 380 | .help_msg = "terminate-all-tasks(e)", |
1da177e4 LT |
381 | .action_msg = "Terminate All Tasks", |
382 | .enable_mask = SYSRQ_ENABLE_SIGNAL, | |
383 | }; | |
384 | ||
65f27f38 | 385 | static void moom_callback(struct work_struct *ignored) |
1da177e4 | 386 | { |
6e0fc46d DR |
387 | const gfp_t gfp_mask = GFP_KERNEL; |
388 | struct oom_control oc = { | |
389 | .zonelist = node_zonelist(first_memory_node, gfp_mask), | |
390 | .nodemask = NULL, | |
2a966b77 | 391 | .memcg = NULL, |
6e0fc46d | 392 | .gfp_mask = gfp_mask, |
54e9e291 | 393 | .order = -1, |
6e0fc46d DR |
394 | }; |
395 | ||
dc56401f | 396 | mutex_lock(&oom_lock); |
6e0fc46d | 397 | if (!out_of_memory(&oc)) |
d75da004 | 398 | pr_info("OOM request ignored. No task eligible\n"); |
dc56401f | 399 | mutex_unlock(&oom_lock); |
1da177e4 LT |
400 | } |
401 | ||
65f27f38 | 402 | static DECLARE_WORK(moom_work, moom_callback); |
1da177e4 | 403 | |
1495cc9d | 404 | static void sysrq_handle_moom(int key) |
1da177e4 LT |
405 | { |
406 | schedule_work(&moom_work); | |
407 | } | |
7fffe31d | 408 | static const struct sysrq_key_op sysrq_moom_op = { |
1da177e4 | 409 | .handler = sysrq_handle_moom, |
afa80ccb | 410 | .help_msg = "memory-full-oom-kill(f)", |
1da177e4 | 411 | .action_msg = "Manual OOM execution", |
b4236f81 | 412 | .enable_mask = SYSRQ_ENABLE_SIGNAL, |
1da177e4 LT |
413 | }; |
414 | ||
8ec8719f | 415 | #ifdef CONFIG_BLOCK |
1495cc9d | 416 | static void sysrq_handle_thaw(int key) |
c2d75438 ES |
417 | { |
418 | emergency_thaw_all(); | |
419 | } | |
7fffe31d | 420 | static const struct sysrq_key_op sysrq_thaw_op = { |
c2d75438 | 421 | .handler = sysrq_handle_thaw, |
afa80ccb | 422 | .help_msg = "thaw-filesystems(j)", |
c2d75438 ES |
423 | .action_msg = "Emergency Thaw of all frozen filesystems", |
424 | .enable_mask = SYSRQ_ENABLE_SIGNAL, | |
425 | }; | |
8ec8719f JW |
426 | #else |
427 | #define sysrq_thaw_op (*(const struct sysrq_key_op *)NULL) | |
428 | #endif | |
c2d75438 | 429 | |
1495cc9d | 430 | static void sysrq_handle_kill(int key) |
1da177e4 LT |
431 | { |
432 | send_sig_all(SIGKILL); | |
a8fe19eb | 433 | console_loglevel = CONSOLE_LOGLEVEL_DEBUG; |
1da177e4 | 434 | } |
7fffe31d | 435 | static const struct sysrq_key_op sysrq_kill_op = { |
1da177e4 | 436 | .handler = sysrq_handle_kill, |
afa80ccb | 437 | .help_msg = "kill-all-tasks(i)", |
1da177e4 LT |
438 | .action_msg = "Kill All Tasks", |
439 | .enable_mask = SYSRQ_ENABLE_SIGNAL, | |
440 | }; | |
441 | ||
1495cc9d | 442 | static void sysrq_handle_unrt(int key) |
1da177e4 LT |
443 | { |
444 | normalize_rt_tasks(); | |
445 | } | |
7fffe31d | 446 | static const struct sysrq_key_op sysrq_unrt_op = { |
1da177e4 | 447 | .handler = sysrq_handle_unrt, |
afa80ccb | 448 | .help_msg = "nice-all-RT-tasks(n)", |
1da177e4 LT |
449 | .action_msg = "Nice All RT Tasks", |
450 | .enable_mask = SYSRQ_ENABLE_RTNICE, | |
451 | }; | |
452 | ||
453 | /* Key Operations table and lock */ | |
454 | static DEFINE_SPINLOCK(sysrq_key_table_lock); | |
bf36b901 | 455 | |
a27eb0cb | 456 | static const struct sysrq_key_op *sysrq_key_table[62] = { |
bf36b901 AM |
457 | &sysrq_loglevel_op, /* 0 */ |
458 | &sysrq_loglevel_op, /* 1 */ | |
459 | &sysrq_loglevel_op, /* 2 */ | |
460 | &sysrq_loglevel_op, /* 3 */ | |
461 | &sysrq_loglevel_op, /* 4 */ | |
462 | &sysrq_loglevel_op, /* 5 */ | |
463 | &sysrq_loglevel_op, /* 6 */ | |
464 | &sysrq_loglevel_op, /* 7 */ | |
465 | &sysrq_loglevel_op, /* 8 */ | |
466 | &sysrq_loglevel_op, /* 9 */ | |
467 | ||
468 | /* | |
d346cce3 RD |
469 | * a: Don't use for system provided sysrqs, it is handled specially on |
470 | * sparc and will never arrive. | |
bf36b901 AM |
471 | */ |
472 | NULL, /* a */ | |
473 | &sysrq_reboot_op, /* b */ | |
5e351410 | 474 | &sysrq_crash_op, /* c */ |
bf36b901 AM |
475 | &sysrq_showlocks_op, /* d */ |
476 | &sysrq_term_op, /* e */ | |
477 | &sysrq_moom_op, /* f */ | |
364b5b7b | 478 | /* g: May be registered for the kernel debugger */ |
bf36b901 | 479 | NULL, /* g */ |
c2d75438 | 480 | NULL, /* h - reserved for help */ |
bf36b901 | 481 | &sysrq_kill_op, /* i */ |
c2d75438 | 482 | &sysrq_thaw_op, /* j */ |
bf36b901 | 483 | &sysrq_SAK_op, /* k */ |
5045bcae | 484 | &sysrq_showallcpus_op, /* l */ |
bf36b901 AM |
485 | &sysrq_showmem_op, /* m */ |
486 | &sysrq_unrt_op, /* n */ | |
d346cce3 | 487 | /* o: This will often be registered as 'Off' at init time */ |
bf36b901 AM |
488 | NULL, /* o */ |
489 | &sysrq_showregs_op, /* p */ | |
88ad0bf6 | 490 | &sysrq_show_timers_op, /* q */ |
d346cce3 | 491 | &sysrq_unraw_op, /* r */ |
bf36b901 AM |
492 | &sysrq_sync_op, /* s */ |
493 | &sysrq_showstate_op, /* t */ | |
494 | &sysrq_mountro_op, /* u */ | |
364b5b7b | 495 | /* v: May be registered for frame buffer console restore */ |
bf36b901 | 496 | NULL, /* v */ |
d346cce3 | 497 | &sysrq_showstate_blocked_op, /* w */ |
d1e9a4f5 | 498 | /* x: May be registered on mips for TLB dump */ |
d346cce3 | 499 | /* x: May be registered on ppc/powerpc for xmon */ |
916ca14a | 500 | /* x: May be registered on sparc64 for global PMU dump */ |
d346cce3 | 501 | NULL, /* x */ |
93dae5b7 | 502 | /* y: May be registered on sparc64 for global register dump */ |
bf36b901 | 503 | NULL, /* y */ |
69f698ad | 504 | &sysrq_ftrace_dump_op, /* z */ |
a27eb0cb AP |
505 | NULL, /* A */ |
506 | NULL, /* B */ | |
507 | NULL, /* C */ | |
508 | NULL, /* D */ | |
509 | NULL, /* E */ | |
510 | NULL, /* F */ | |
511 | NULL, /* G */ | |
512 | NULL, /* H */ | |
513 | NULL, /* I */ | |
514 | NULL, /* J */ | |
515 | NULL, /* K */ | |
516 | NULL, /* L */ | |
517 | NULL, /* M */ | |
518 | NULL, /* N */ | |
519 | NULL, /* O */ | |
520 | NULL, /* P */ | |
521 | NULL, /* Q */ | |
522 | NULL, /* R */ | |
523 | NULL, /* S */ | |
524 | NULL, /* T */ | |
525 | NULL, /* U */ | |
526 | NULL, /* V */ | |
527 | NULL, /* W */ | |
528 | NULL, /* X */ | |
529 | NULL, /* Y */ | |
530 | NULL, /* Z */ | |
1da177e4 LT |
531 | }; |
532 | ||
533 | /* key2index calculation, -1 on invalid index */ | |
bf36b901 AM |
534 | static int sysrq_key_table_key2index(int key) |
535 | { | |
1da177e4 | 536 | int retval; |
bf36b901 AM |
537 | |
538 | if ((key >= '0') && (key <= '9')) | |
1da177e4 | 539 | retval = key - '0'; |
bf36b901 | 540 | else if ((key >= 'a') && (key <= 'z')) |
1da177e4 | 541 | retval = key + 10 - 'a'; |
a27eb0cb AP |
542 | else if ((key >= 'A') && (key <= 'Z')) |
543 | retval = key + 36 - 'A'; | |
bf36b901 | 544 | else |
1da177e4 | 545 | retval = -1; |
1da177e4 LT |
546 | return retval; |
547 | } | |
548 | ||
549 | /* | |
550 | * get and put functions for the table, exposed to modules. | |
551 | */ | |
23cbedf8 | 552 | static const struct sysrq_key_op *__sysrq_get_key_op(int key) |
bf36b901 | 553 | { |
149ad2c6 XT |
554 | const struct sysrq_key_op *op_p = NULL; |
555 | int i; | |
bf36b901 | 556 | |
1da177e4 | 557 | i = sysrq_key_table_key2index(key); |
bf36b901 | 558 | if (i != -1) |
149ad2c6 | 559 | op_p = sysrq_key_table[i]; |
97f5f0cd | 560 | |
149ad2c6 | 561 | return op_p; |
1da177e4 LT |
562 | } |
563 | ||
23cbedf8 | 564 | static void __sysrq_put_key_op(int key, const struct sysrq_key_op *op_p) |
bf36b901 | 565 | { |
149ad2c6 | 566 | int i = sysrq_key_table_key2index(key); |
1da177e4 | 567 | |
149ad2c6 XT |
568 | if (i != -1) |
569 | sysrq_key_table[i] = op_p; | |
1da177e4 LT |
570 | } |
571 | ||
f335397d | 572 | void __handle_sysrq(int key, bool check_mask) |
1da177e4 | 573 | { |
23cbedf8 | 574 | const struct sysrq_key_op *op_p; |
1da177e4 | 575 | int orig_log_level; |
c39ea0b9 | 576 | int orig_suppress_printk; |
bf36b901 | 577 | int i; |
1da177e4 | 578 | |
c39ea0b9 FT |
579 | orig_suppress_printk = suppress_printk; |
580 | suppress_printk = 0; | |
581 | ||
722773af | 582 | rcu_sysrq_start(); |
984d74a7 | 583 | rcu_read_lock(); |
fb144adc AW |
584 | /* |
585 | * Raise the apparent loglevel to maximum so that the sysrq header | |
586 | * is shown to provide the user with positive feedback. We do not | |
587 | * simply emit this at KERN_EMERG as that would change message | |
588 | * routing in the consumers of /proc/kmsg. | |
589 | */ | |
1da177e4 | 590 | orig_log_level = console_loglevel; |
a8fe19eb | 591 | console_loglevel = CONSOLE_LOGLEVEL_DEFAULT; |
1da177e4 | 592 | |
149ad2c6 XT |
593 | op_p = __sysrq_get_key_op(key); |
594 | if (op_p) { | |
bf36b901 AM |
595 | /* |
596 | * Should we check for enabled operations (/proc/sysrq-trigger | |
597 | * should not) and is the invoked operation enabled? | |
598 | */ | |
5d6f647f | 599 | if (!check_mask || sysrq_on_mask(op_p->enable_mask)) { |
c3fee609 | 600 | pr_info("%s\n", op_p->action_msg); |
1da177e4 | 601 | console_loglevel = orig_log_level; |
1495cc9d | 602 | op_p->handler(key); |
bf36b901 | 603 | } else { |
c3fee609 | 604 | pr_info("This sysrq operation is disabled.\n"); |
075e1a0c | 605 | console_loglevel = orig_log_level; |
bf36b901 | 606 | } |
1da177e4 | 607 | } else { |
c3fee609 | 608 | pr_info("HELP : "); |
1da177e4 | 609 | /* Only print the help msg once per handler */ |
bf36b901 AM |
610 | for (i = 0; i < ARRAY_SIZE(sysrq_key_table); i++) { |
611 | if (sysrq_key_table[i]) { | |
612 | int j; | |
613 | ||
614 | for (j = 0; sysrq_key_table[i] != | |
615 | sysrq_key_table[j]; j++) | |
616 | ; | |
617 | if (j != i) | |
618 | continue; | |
401e4a7c | 619 | pr_cont("%s ", sysrq_key_table[i]->help_msg); |
bf36b901 | 620 | } |
1da177e4 | 621 | } |
401e4a7c | 622 | pr_cont("\n"); |
1da177e4 LT |
623 | console_loglevel = orig_log_level; |
624 | } | |
984d74a7 | 625 | rcu_read_unlock(); |
722773af | 626 | rcu_sysrq_end(); |
c39ea0b9 FT |
627 | |
628 | suppress_printk = orig_suppress_printk; | |
1da177e4 LT |
629 | } |
630 | ||
f335397d | 631 | void handle_sysrq(int key) |
1da177e4 | 632 | { |
5d6f647f | 633 | if (sysrq_on()) |
f335397d | 634 | __handle_sysrq(key, true); |
1da177e4 | 635 | } |
bf36b901 | 636 | EXPORT_SYMBOL(handle_sysrq); |
1da177e4 | 637 | |
97f5f0cd | 638 | #ifdef CONFIG_INPUT |
ffb6e0c9 | 639 | static int sysrq_reset_downtime_ms; |
97f5f0cd DT |
640 | |
641 | /* Simple translation table for the SysRq keys */ | |
fcb71930 | 642 | static const unsigned char sysrq_xlate[KEY_CNT] = |
149ad2c6 XT |
643 | "\000\0331234567890-=\177\t" /* 0x00 - 0x0f */ |
644 | "qwertyuiop[]\r\000as" /* 0x10 - 0x1f */ | |
645 | "dfghjkl;'`\000\\zxcv" /* 0x20 - 0x2f */ | |
646 | "bnm,./\000*\000 \000\201\202\203\204\205" /* 0x30 - 0x3f */ | |
647 | "\206\207\210\211\212\000\000789-456+1" /* 0x40 - 0x4f */ | |
648 | "230\177\000\000\213\214\000\000\000\000\000\000\000\000\000\000" /* 0x50 - 0x5f */ | |
649 | "\r\000/"; /* 0x60 - 0x6f */ | |
97f5f0cd | 650 | |
fcb71930 DT |
651 | struct sysrq_state { |
652 | struct input_handle handle; | |
653 | struct work_struct reinject_work; | |
654 | unsigned long key_down[BITS_TO_LONGS(KEY_CNT)]; | |
655 | unsigned int alt; | |
656 | unsigned int alt_use; | |
a27eb0cb AP |
657 | unsigned int shift; |
658 | unsigned int shift_use; | |
fcb71930 DT |
659 | bool active; |
660 | bool need_reinject; | |
7ab7b5ad | 661 | bool reinjecting; |
154b7a48 MP |
662 | |
663 | /* reset sequence handling */ | |
664 | bool reset_canceled; | |
3d289517 | 665 | bool reset_requested; |
154b7a48 MP |
666 | unsigned long reset_keybit[BITS_TO_LONGS(KEY_CNT)]; |
667 | int reset_seq_len; | |
668 | int reset_seq_cnt; | |
669 | int reset_seq_version; | |
39030786 | 670 | struct timer_list keyreset_timer; |
fcb71930 DT |
671 | }; |
672 | ||
154b7a48 MP |
673 | #define SYSRQ_KEY_RESET_MAX 20 /* Should be plenty */ |
674 | static unsigned short sysrq_reset_seq[SYSRQ_KEY_RESET_MAX]; | |
675 | static unsigned int sysrq_reset_seq_len; | |
676 | static unsigned int sysrq_reset_seq_version = 1; | |
677 | ||
678 | static void sysrq_parse_reset_sequence(struct sysrq_state *state) | |
679 | { | |
680 | int i; | |
681 | unsigned short key; | |
682 | ||
683 | state->reset_seq_cnt = 0; | |
684 | ||
685 | for (i = 0; i < sysrq_reset_seq_len; i++) { | |
686 | key = sysrq_reset_seq[i]; | |
687 | ||
688 | if (key == KEY_RESERVED || key > KEY_MAX) | |
689 | break; | |
690 | ||
691 | __set_bit(key, state->reset_keybit); | |
692 | state->reset_seq_len++; | |
693 | ||
694 | if (test_bit(key, state->key_down)) | |
695 | state->reset_seq_cnt++; | |
696 | } | |
697 | ||
698 | /* Disable reset until old keys are not released */ | |
699 | state->reset_canceled = state->reset_seq_cnt != 0; | |
700 | ||
701 | state->reset_seq_version = sysrq_reset_seq_version; | |
702 | } | |
703 | ||
8c318fa9 | 704 | static void sysrq_do_reset(struct timer_list *t) |
39030786 | 705 | { |
8c318fa9 | 706 | struct sysrq_state *state = from_timer(state, t, keyreset_timer); |
3d289517 MP |
707 | |
708 | state->reset_requested = true; | |
709 | ||
8fefbc6d | 710 | orderly_reboot(); |
39030786 MP |
711 | } |
712 | ||
713 | static void sysrq_handle_reset_request(struct sysrq_state *state) | |
714 | { | |
3d289517 MP |
715 | if (state->reset_requested) |
716 | __handle_sysrq(sysrq_xlate[KEY_B], false); | |
717 | ||
39030786 MP |
718 | if (sysrq_reset_downtime_ms) |
719 | mod_timer(&state->keyreset_timer, | |
720 | jiffies + msecs_to_jiffies(sysrq_reset_downtime_ms)); | |
721 | else | |
8c318fa9 | 722 | sysrq_do_reset(&state->keyreset_timer); |
39030786 MP |
723 | } |
724 | ||
725 | static void sysrq_detect_reset_sequence(struct sysrq_state *state, | |
154b7a48 MP |
726 | unsigned int code, int value) |
727 | { | |
728 | if (!test_bit(code, state->reset_keybit)) { | |
729 | /* | |
730 | * Pressing any key _not_ in reset sequence cancels | |
39030786 MP |
731 | * the reset sequence. Also cancelling the timer in |
732 | * case additional keys were pressed after a reset | |
733 | * has been requested. | |
154b7a48 | 734 | */ |
39030786 | 735 | if (value && state->reset_seq_cnt) { |
154b7a48 | 736 | state->reset_canceled = true; |
39030786 MP |
737 | del_timer(&state->keyreset_timer); |
738 | } | |
154b7a48 | 739 | } else if (value == 0) { |
39030786 MP |
740 | /* |
741 | * Key release - all keys in the reset sequence need | |
742 | * to be pressed and held for the reset timeout | |
743 | * to hold. | |
744 | */ | |
745 | del_timer(&state->keyreset_timer); | |
746 | ||
154b7a48 MP |
747 | if (--state->reset_seq_cnt == 0) |
748 | state->reset_canceled = false; | |
749 | } else if (value == 1) { | |
750 | /* key press, not autorepeat */ | |
751 | if (++state->reset_seq_cnt == state->reset_seq_len && | |
752 | !state->reset_canceled) { | |
39030786 | 753 | sysrq_handle_reset_request(state); |
154b7a48 MP |
754 | } |
755 | } | |
154b7a48 MP |
756 | } |
757 | ||
4c076eb0 MP |
758 | #ifdef CONFIG_OF |
759 | static void sysrq_of_get_keyreset_config(void) | |
760 | { | |
761 | u32 key; | |
762 | struct device_node *np; | |
763 | struct property *prop; | |
764 | const __be32 *p; | |
765 | ||
766 | np = of_find_node_by_path("/chosen/linux,sysrq-reset-seq"); | |
767 | if (!np) { | |
768 | pr_debug("No sysrq node found"); | |
769 | return; | |
770 | } | |
771 | ||
772 | /* Reset in case a __weak definition was present */ | |
773 | sysrq_reset_seq_len = 0; | |
774 | ||
775 | of_property_for_each_u32(np, "keyset", prop, p, key) { | |
776 | if (key == KEY_RESERVED || key > KEY_MAX || | |
777 | sysrq_reset_seq_len == SYSRQ_KEY_RESET_MAX) | |
778 | break; | |
779 | ||
780 | sysrq_reset_seq[sysrq_reset_seq_len++] = (unsigned short)key; | |
781 | } | |
782 | ||
783 | /* Get reset timeout if any. */ | |
784 | of_property_read_u32(np, "timeout-ms", &sysrq_reset_downtime_ms); | |
279070b9 YL |
785 | |
786 | of_node_put(np); | |
4c076eb0 MP |
787 | } |
788 | #else | |
789 | static void sysrq_of_get_keyreset_config(void) | |
790 | { | |
791 | } | |
792 | #endif | |
793 | ||
fcb71930 DT |
794 | static void sysrq_reinject_alt_sysrq(struct work_struct *work) |
795 | { | |
796 | struct sysrq_state *sysrq = | |
797 | container_of(work, struct sysrq_state, reinject_work); | |
798 | struct input_handle *handle = &sysrq->handle; | |
799 | unsigned int alt_code = sysrq->alt_use; | |
800 | ||
801 | if (sysrq->need_reinject) { | |
7ab7b5ad DT |
802 | /* we do not want the assignment to be reordered */ |
803 | sysrq->reinjecting = true; | |
804 | mb(); | |
805 | ||
fcb71930 DT |
806 | /* Simulate press and release of Alt + SysRq */ |
807 | input_inject_event(handle, EV_KEY, alt_code, 1); | |
808 | input_inject_event(handle, EV_KEY, KEY_SYSRQ, 1); | |
809 | input_inject_event(handle, EV_SYN, SYN_REPORT, 1); | |
810 | ||
811 | input_inject_event(handle, EV_KEY, KEY_SYSRQ, 0); | |
812 | input_inject_event(handle, EV_KEY, alt_code, 0); | |
813 | input_inject_event(handle, EV_SYN, SYN_REPORT, 1); | |
7ab7b5ad DT |
814 | |
815 | mb(); | |
816 | sysrq->reinjecting = false; | |
fcb71930 DT |
817 | } |
818 | } | |
97f5f0cd | 819 | |
154b7a48 MP |
820 | static bool sysrq_handle_keypress(struct sysrq_state *sysrq, |
821 | unsigned int code, int value) | |
97f5f0cd | 822 | { |
fcb71930 | 823 | bool was_active = sysrq->active; |
1966cb22 DT |
824 | bool suppress; |
825 | ||
154b7a48 | 826 | switch (code) { |
7ab7b5ad | 827 | |
154b7a48 MP |
828 | case KEY_LEFTALT: |
829 | case KEY_RIGHTALT: | |
830 | if (!value) { | |
831 | /* One of ALTs is being released */ | |
832 | if (sysrq->active && code == sysrq->alt_use) | |
833 | sysrq->active = false; | |
1966cb22 | 834 | |
154b7a48 MP |
835 | sysrq->alt = KEY_RESERVED; |
836 | ||
837 | } else if (value != 2) { | |
838 | sysrq->alt = code; | |
839 | sysrq->need_reinject = false; | |
840 | } | |
fcb71930 | 841 | break; |
97f5f0cd | 842 | |
a27eb0cb AP |
843 | case KEY_LEFTSHIFT: |
844 | case KEY_RIGHTSHIFT: | |
845 | if (!value) | |
846 | sysrq->shift = KEY_RESERVED; | |
847 | else if (value != 2) | |
848 | sysrq->shift = code; | |
3aee752c OP |
849 | if (sysrq->active) |
850 | sysrq->shift_use = sysrq->shift; | |
a27eb0cb AP |
851 | break; |
852 | ||
154b7a48 MP |
853 | case KEY_SYSRQ: |
854 | if (value == 1 && sysrq->alt != KEY_RESERVED) { | |
855 | sysrq->active = true; | |
856 | sysrq->alt_use = sysrq->alt; | |
a27eb0cb AP |
857 | /* either RESERVED (for released) or actual code */ |
858 | sysrq->shift_use = sysrq->shift; | |
154b7a48 MP |
859 | /* |
860 | * If nothing else will be pressed we'll need | |
861 | * to re-inject Alt-SysRq keysroke. | |
862 | */ | |
863 | sysrq->need_reinject = true; | |
864 | } | |
97f5f0cd | 865 | |
154b7a48 MP |
866 | /* |
867 | * Pretend that sysrq was never pressed at all. This | |
868 | * is needed to properly handle KGDB which will try | |
869 | * to release all keys after exiting debugger. If we | |
870 | * do not clear key bit it KGDB will end up sending | |
871 | * release events for Alt and SysRq, potentially | |
872 | * triggering print screen function. | |
873 | */ | |
874 | if (sysrq->active) | |
875 | clear_bit(KEY_SYSRQ, sysrq->handle.dev->key); | |
f5dec511 | 876 | |
154b7a48 | 877 | break; |
fcb71930 | 878 | |
154b7a48 MP |
879 | default: |
880 | if (sysrq->active && value && value != 2) { | |
a27eb0cb AP |
881 | unsigned char c = sysrq_xlate[code]; |
882 | ||
154b7a48 | 883 | sysrq->need_reinject = false; |
a27eb0cb AP |
884 | if (sysrq->shift_use != KEY_RESERVED) |
885 | c = toupper(c); | |
886 | __handle_sysrq(c, true); | |
154b7a48 MP |
887 | } |
888 | break; | |
889 | } | |
fcb71930 | 890 | |
154b7a48 | 891 | suppress = sysrq->active; |
fcb71930 | 892 | |
154b7a48 | 893 | if (!sysrq->active) { |
fcb71930 | 894 | |
154b7a48 MP |
895 | /* |
896 | * See if reset sequence has changed since the last time. | |
897 | */ | |
898 | if (sysrq->reset_seq_version != sysrq_reset_seq_version) | |
899 | sysrq_parse_reset_sequence(sysrq); | |
fcb71930 | 900 | |
154b7a48 MP |
901 | /* |
902 | * If we are not suppressing key presses keep track of | |
903 | * keyboard state so we can release keys that have been | |
904 | * pressed before entering SysRq mode. | |
905 | */ | |
906 | if (value) | |
907 | set_bit(code, sysrq->key_down); | |
908 | else | |
909 | clear_bit(code, sysrq->key_down); | |
910 | ||
911 | if (was_active) | |
912 | schedule_work(&sysrq->reinject_work); | |
913 | ||
39030786 MP |
914 | /* Check for reset sequence */ |
915 | sysrq_detect_reset_sequence(sysrq, code, value); | |
97f5f0cd | 916 | |
154b7a48 MP |
917 | } else if (value == 0 && test_and_clear_bit(code, sysrq->key_down)) { |
918 | /* | |
919 | * Pass on release events for keys that was pressed before | |
920 | * entering SysRq mode. | |
921 | */ | |
922 | suppress = false; | |
923 | } | |
fcb71930 | 924 | |
154b7a48 MP |
925 | return suppress; |
926 | } | |
fcb71930 | 927 | |
154b7a48 MP |
928 | static bool sysrq_filter(struct input_handle *handle, |
929 | unsigned int type, unsigned int code, int value) | |
930 | { | |
931 | struct sysrq_state *sysrq = handle->private; | |
932 | bool suppress; | |
fcb71930 | 933 | |
154b7a48 MP |
934 | /* |
935 | * Do not filter anything if we are in the process of re-injecting | |
936 | * Alt+SysRq combination. | |
937 | */ | |
938 | if (sysrq->reinjecting) | |
939 | return false; | |
940 | ||
941 | switch (type) { | |
942 | ||
943 | case EV_SYN: | |
944 | suppress = false; | |
945 | break; | |
946 | ||
947 | case EV_KEY: | |
948 | suppress = sysrq_handle_keypress(sysrq, code, value); | |
97f5f0cd DT |
949 | break; |
950 | ||
951 | default: | |
fcb71930 | 952 | suppress = sysrq->active; |
97f5f0cd DT |
953 | break; |
954 | } | |
955 | ||
1966cb22 | 956 | return suppress; |
97f5f0cd DT |
957 | } |
958 | ||
959 | static int sysrq_connect(struct input_handler *handler, | |
960 | struct input_dev *dev, | |
961 | const struct input_device_id *id) | |
962 | { | |
fcb71930 | 963 | struct sysrq_state *sysrq; |
97f5f0cd DT |
964 | int error; |
965 | ||
fcb71930 DT |
966 | sysrq = kzalloc(sizeof(struct sysrq_state), GFP_KERNEL); |
967 | if (!sysrq) | |
97f5f0cd DT |
968 | return -ENOMEM; |
969 | ||
fcb71930 DT |
970 | INIT_WORK(&sysrq->reinject_work, sysrq_reinject_alt_sysrq); |
971 | ||
972 | sysrq->handle.dev = dev; | |
973 | sysrq->handle.handler = handler; | |
974 | sysrq->handle.name = "sysrq"; | |
975 | sysrq->handle.private = sysrq; | |
8c318fa9 | 976 | timer_setup(&sysrq->keyreset_timer, sysrq_do_reset, 0); |
97f5f0cd | 977 | |
fcb71930 | 978 | error = input_register_handle(&sysrq->handle); |
97f5f0cd DT |
979 | if (error) { |
980 | pr_err("Failed to register input sysrq handler, error %d\n", | |
981 | error); | |
982 | goto err_free; | |
983 | } | |
984 | ||
fcb71930 | 985 | error = input_open_device(&sysrq->handle); |
97f5f0cd DT |
986 | if (error) { |
987 | pr_err("Failed to open input device, error %d\n", error); | |
988 | goto err_unregister; | |
989 | } | |
990 | ||
991 | return 0; | |
992 | ||
993 | err_unregister: | |
fcb71930 | 994 | input_unregister_handle(&sysrq->handle); |
97f5f0cd | 995 | err_free: |
fcb71930 | 996 | kfree(sysrq); |
97f5f0cd DT |
997 | return error; |
998 | } | |
999 | ||
1000 | static void sysrq_disconnect(struct input_handle *handle) | |
1001 | { | |
fcb71930 DT |
1002 | struct sysrq_state *sysrq = handle->private; |
1003 | ||
97f5f0cd | 1004 | input_close_device(handle); |
fcb71930 | 1005 | cancel_work_sync(&sysrq->reinject_work); |
292a089d | 1006 | timer_shutdown_sync(&sysrq->keyreset_timer); |
97f5f0cd | 1007 | input_unregister_handle(handle); |
fcb71930 | 1008 | kfree(sysrq); |
97f5f0cd DT |
1009 | } |
1010 | ||
1011 | /* | |
1966cb22 DT |
1012 | * We are matching on KEY_LEFTALT instead of KEY_SYSRQ because not all |
1013 | * keyboards have SysRq key predefined and so user may add it to keymap | |
97f5f0cd DT |
1014 | * later, but we expect all such keyboards to have left alt. |
1015 | */ | |
1016 | static const struct input_device_id sysrq_ids[] = { | |
1017 | { | |
1018 | .flags = INPUT_DEVICE_ID_MATCH_EVBIT | | |
1019 | INPUT_DEVICE_ID_MATCH_KEYBIT, | |
802c0388 AM |
1020 | .evbit = { [BIT_WORD(EV_KEY)] = BIT_MASK(EV_KEY) }, |
1021 | .keybit = { [BIT_WORD(KEY_LEFTALT)] = BIT_MASK(KEY_LEFTALT) }, | |
97f5f0cd DT |
1022 | }, |
1023 | { }, | |
1024 | }; | |
1025 | ||
1026 | static struct input_handler sysrq_handler = { | |
1027 | .filter = sysrq_filter, | |
1028 | .connect = sysrq_connect, | |
1029 | .disconnect = sysrq_disconnect, | |
1030 | .name = "sysrq", | |
1031 | .id_table = sysrq_ids, | |
1032 | }; | |
1033 | ||
97f5f0cd DT |
1034 | static inline void sysrq_register_handler(void) |
1035 | { | |
1036 | int error; | |
1037 | ||
4c076eb0 MP |
1038 | sysrq_of_get_keyreset_config(); |
1039 | ||
97f5f0cd DT |
1040 | error = input_register_handler(&sysrq_handler); |
1041 | if (error) | |
1042 | pr_err("Failed to register input handler, error %d", error); | |
97f5f0cd DT |
1043 | } |
1044 | ||
1045 | static inline void sysrq_unregister_handler(void) | |
1046 | { | |
f06327d1 | 1047 | input_unregister_handler(&sysrq_handler); |
97f5f0cd DT |
1048 | } |
1049 | ||
154b7a48 MP |
1050 | static int sysrq_reset_seq_param_set(const char *buffer, |
1051 | const struct kernel_param *kp) | |
1052 | { | |
1053 | unsigned long val; | |
1054 | int error; | |
1055 | ||
86b40567 | 1056 | error = kstrtoul(buffer, 0, &val); |
154b7a48 MP |
1057 | if (error < 0) |
1058 | return error; | |
1059 | ||
1060 | if (val > KEY_MAX) | |
1061 | return -EINVAL; | |
1062 | ||
1063 | *((unsigned short *)kp->arg) = val; | |
1064 | sysrq_reset_seq_version++; | |
1065 | ||
1066 | return 0; | |
1067 | } | |
1068 | ||
9c27847d | 1069 | static const struct kernel_param_ops param_ops_sysrq_reset_seq = { |
154b7a48 MP |
1070 | .get = param_get_ushort, |
1071 | .set = sysrq_reset_seq_param_set, | |
1072 | }; | |
1073 | ||
1074 | #define param_check_sysrq_reset_seq(name, p) \ | |
1075 | __param_check(name, p, unsigned short) | |
1076 | ||
3bce6f64 PG |
1077 | /* |
1078 | * not really modular, but the easiest way to keep compat with existing | |
1079 | * bootargs behaviour is to continue using module_param here. | |
1080 | */ | |
154b7a48 MP |
1081 | module_param_array_named(reset_seq, sysrq_reset_seq, sysrq_reset_seq, |
1082 | &sysrq_reset_seq_len, 0644); | |
1083 | ||
39030786 MP |
1084 | module_param_named(sysrq_downtime_ms, sysrq_reset_downtime_ms, int, 0644); |
1085 | ||
97f5f0cd DT |
1086 | #else |
1087 | ||
1088 | static inline void sysrq_register_handler(void) | |
1089 | { | |
1090 | } | |
1091 | ||
1092 | static inline void sysrq_unregister_handler(void) | |
1093 | { | |
1094 | } | |
1095 | ||
1096 | #endif /* CONFIG_INPUT */ | |
1097 | ||
1098 | int sysrq_toggle_support(int enable_mask) | |
1099 | { | |
1100 | bool was_enabled = sysrq_on(); | |
1101 | ||
1102 | sysrq_enabled = enable_mask; | |
1103 | ||
1104 | if (was_enabled != sysrq_on()) { | |
1105 | if (sysrq_on()) | |
1106 | sysrq_register_handler(); | |
1107 | else | |
1108 | sysrq_unregister_handler(); | |
1109 | } | |
1110 | ||
1111 | return 0; | |
1112 | } | |
66bb1c95 | 1113 | EXPORT_SYMBOL_GPL(sysrq_toggle_support); |
97f5f0cd | 1114 | |
23cbedf8 | 1115 | static int __sysrq_swap_key_ops(int key, const struct sysrq_key_op *insert_op_p, |
149ad2c6 | 1116 | const struct sysrq_key_op *remove_op_p) |
bf36b901 | 1117 | { |
1da177e4 | 1118 | int retval; |
1da177e4 | 1119 | |
984d74a7 | 1120 | spin_lock(&sysrq_key_table_lock); |
1da177e4 LT |
1121 | if (__sysrq_get_key_op(key) == remove_op_p) { |
1122 | __sysrq_put_key_op(key, insert_op_p); | |
1123 | retval = 0; | |
1124 | } else { | |
1125 | retval = -1; | |
1126 | } | |
984d74a7 RR |
1127 | spin_unlock(&sysrq_key_table_lock); |
1128 | ||
1129 | /* | |
1130 | * A concurrent __handle_sysrq either got the old op or the new op. | |
1131 | * Wait for it to go away before returning, so the code for an old | |
1132 | * op is not freed (eg. on module unload) while it is in use. | |
1133 | */ | |
1134 | synchronize_rcu(); | |
1135 | ||
1da177e4 LT |
1136 | return retval; |
1137 | } | |
1138 | ||
23cbedf8 | 1139 | int register_sysrq_key(int key, const struct sysrq_key_op *op_p) |
1da177e4 LT |
1140 | { |
1141 | return __sysrq_swap_key_ops(key, op_p, NULL); | |
1142 | } | |
bf36b901 | 1143 | EXPORT_SYMBOL(register_sysrq_key); |
1da177e4 | 1144 | |
23cbedf8 | 1145 | int unregister_sysrq_key(int key, const struct sysrq_key_op *op_p) |
1da177e4 LT |
1146 | { |
1147 | return __sysrq_swap_key_ops(key, NULL, op_p); | |
1148 | } | |
1da177e4 | 1149 | EXPORT_SYMBOL(unregister_sysrq_key); |
f40cbaa5 AD |
1150 | |
1151 | #ifdef CONFIG_PROC_FS | |
1152 | /* | |
1153 | * writing 'C' to /proc/sysrq-trigger is like sysrq-C | |
1154 | */ | |
1155 | static ssize_t write_sysrq_trigger(struct file *file, const char __user *buf, | |
1156 | size_t count, loff_t *ppos) | |
1157 | { | |
1158 | if (count) { | |
1159 | char c; | |
1160 | ||
1161 | if (get_user(c, buf)) | |
1162 | return -EFAULT; | |
f335397d | 1163 | __handle_sysrq(c, false); |
f40cbaa5 | 1164 | } |
97f5f0cd | 1165 | |
f40cbaa5 AD |
1166 | return count; |
1167 | } | |
1168 | ||
97a32539 AD |
1169 | static const struct proc_ops sysrq_trigger_proc_ops = { |
1170 | .proc_write = write_sysrq_trigger, | |
1171 | .proc_lseek = noop_llseek, | |
f40cbaa5 AD |
1172 | }; |
1173 | ||
97f5f0cd DT |
1174 | static void sysrq_init_procfs(void) |
1175 | { | |
1176 | if (!proc_create("sysrq-trigger", S_IWUSR, NULL, | |
97a32539 | 1177 | &sysrq_trigger_proc_ops)) |
97f5f0cd DT |
1178 | pr_err("Failed to register proc interface\n"); |
1179 | } | |
1180 | ||
1181 | #else | |
1182 | ||
1183 | static inline void sysrq_init_procfs(void) | |
1184 | { | |
1185 | } | |
1186 | ||
1187 | #endif /* CONFIG_PROC_FS */ | |
1188 | ||
f40cbaa5 AD |
1189 | static int __init sysrq_init(void) |
1190 | { | |
97f5f0cd DT |
1191 | sysrq_init_procfs(); |
1192 | ||
1193 | if (sysrq_on()) | |
1194 | sysrq_register_handler(); | |
1195 | ||
f40cbaa5 AD |
1196 | return 0; |
1197 | } | |
3bce6f64 | 1198 | device_initcall(sysrq_init); |