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