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> |
1da177e4 LT |
22 | #include <linux/interrupt.h> |
23 | #include <linux/mm.h> | |
24 | #include <linux/fs.h> | |
1da177e4 LT |
25 | #include <linux/mount.h> |
26 | #include <linux/kdev_t.h> | |
27 | #include <linux/major.h> | |
28 | #include <linux/reboot.h> | |
29 | #include <linux/sysrq.h> | |
30 | #include <linux/kbd_kern.h> | |
f40cbaa5 | 31 | #include <linux/proc_fs.h> |
c1dc0b9c | 32 | #include <linux/nmi.h> |
1da177e4 | 33 | #include <linux/quotaops.h> |
cdd6c482 | 34 | #include <linux/perf_event.h> |
1da177e4 LT |
35 | #include <linux/kernel.h> |
36 | #include <linux/module.h> | |
37 | #include <linux/suspend.h> | |
38 | #include <linux/writeback.h> | |
1da177e4 LT |
39 | #include <linux/swap.h> |
40 | #include <linux/spinlock.h> | |
41 | #include <linux/vt_kern.h> | |
42 | #include <linux/workqueue.h> | |
88ad0bf6 | 43 | #include <linux/hrtimer.h> |
5a3135c2 | 44 | #include <linux/oom.h> |
5a0e3ad6 | 45 | #include <linux/slab.h> |
97f5f0cd | 46 | #include <linux/input.h> |
ff01bb48 | 47 | #include <linux/uaccess.h> |
154b7a48 | 48 | #include <linux/moduleparam.h> |
39030786 | 49 | #include <linux/jiffies.h> |
3d289517 | 50 | #include <linux/syscalls.h> |
4c076eb0 | 51 | #include <linux/of.h> |
722773af | 52 | #include <linux/rcupdate.h> |
1da177e4 LT |
53 | |
54 | #include <asm/ptrace.h> | |
2033b0c3 | 55 | #include <asm/irq_regs.h> |
1da177e4 LT |
56 | |
57 | /* Whether we react on sysrq keys or just ignore them */ | |
8eaede49 | 58 | static int __read_mostly sysrq_enabled = CONFIG_MAGIC_SYSRQ_DEFAULT_ENABLE; |
97f5f0cd | 59 | static bool __read_mostly sysrq_always_enabled; |
5d6f647f | 60 | |
97f5f0cd | 61 | static bool sysrq_on(void) |
5d6f647f | 62 | { |
97f5f0cd | 63 | return sysrq_enabled || sysrq_always_enabled; |
5d6f647f IM |
64 | } |
65 | ||
eaee4172 DS |
66 | /** |
67 | * sysrq_mask - Getter for sysrq_enabled mask. | |
68 | * | |
69 | * Return: 1 if sysrq is always enabled, enabled sysrq_key_op mask otherwise. | |
70 | */ | |
71 | int sysrq_mask(void) | |
72 | { | |
73 | if (sysrq_always_enabled) | |
74 | return 1; | |
75 | return sysrq_enabled; | |
76 | } | |
66bb1c95 | 77 | EXPORT_SYMBOL_GPL(sysrq_mask); |
eaee4172 | 78 | |
5d6f647f IM |
79 | /* |
80 | * A value of 1 means 'all', other nonzero values are an op mask: | |
81 | */ | |
97f5f0cd | 82 | static bool sysrq_on_mask(int mask) |
5d6f647f | 83 | { |
97f5f0cd DT |
84 | return sysrq_always_enabled || |
85 | sysrq_enabled == 1 || | |
86 | (sysrq_enabled & mask); | |
5d6f647f IM |
87 | } |
88 | ||
89 | static int __init sysrq_always_enabled_setup(char *str) | |
90 | { | |
97f5f0cd DT |
91 | sysrq_always_enabled = true; |
92 | pr_info("sysrq always enabled.\n"); | |
5d6f647f IM |
93 | |
94 | return 1; | |
95 | } | |
96 | ||
97 | __setup("sysrq_always_enabled", sysrq_always_enabled_setup); | |
98 | ||
1da177e4 | 99 | |
1495cc9d | 100 | static void sysrq_handle_loglevel(int key) |
1da177e4 LT |
101 | { |
102 | int i; | |
97f5f0cd | 103 | |
1da177e4 | 104 | i = key - '0'; |
a8fe19eb | 105 | console_loglevel = CONSOLE_LOGLEVEL_DEFAULT; |
401e4a7c | 106 | pr_info("Loglevel set to %d\n", i); |
1da177e4 | 107 | console_loglevel = i; |
bf36b901 | 108 | } |
7fffe31d | 109 | static const struct sysrq_key_op sysrq_loglevel_op = { |
1da177e4 | 110 | .handler = sysrq_handle_loglevel, |
208b95ce | 111 | .help_msg = "loglevel(0-9)", |
1da177e4 LT |
112 | .action_msg = "Changing Loglevel", |
113 | .enable_mask = SYSRQ_ENABLE_LOG, | |
114 | }; | |
115 | ||
1da177e4 | 116 | #ifdef CONFIG_VT |
1495cc9d | 117 | static void sysrq_handle_SAK(int key) |
1da177e4 | 118 | { |
8b6312f4 | 119 | struct work_struct *SAK_work = &vc_cons[fg_console].SAK_work; |
8b6312f4 | 120 | schedule_work(SAK_work); |
1da177e4 | 121 | } |
7fffe31d | 122 | static const struct sysrq_key_op sysrq_SAK_op = { |
1da177e4 | 123 | .handler = sysrq_handle_SAK, |
afa80ccb | 124 | .help_msg = "sak(k)", |
1da177e4 LT |
125 | .action_msg = "SAK", |
126 | .enable_mask = SYSRQ_ENABLE_KEYBOARD, | |
127 | }; | |
bf36b901 | 128 | #else |
7fffe31d | 129 | #define sysrq_SAK_op (*(const struct sysrq_key_op *)NULL) |
1da177e4 LT |
130 | #endif |
131 | ||
132 | #ifdef CONFIG_VT | |
1495cc9d | 133 | static void sysrq_handle_unraw(int key) |
1da177e4 | 134 | { |
079c9534 | 135 | vt_reset_unicode(fg_console); |
1da177e4 | 136 | } |
079c9534 | 137 | |
7fffe31d | 138 | static const struct sysrq_key_op sysrq_unraw_op = { |
1da177e4 | 139 | .handler = sysrq_handle_unraw, |
afa80ccb | 140 | .help_msg = "unraw(r)", |
2e8ecb9d | 141 | .action_msg = "Keyboard mode set to system default", |
1da177e4 LT |
142 | .enable_mask = SYSRQ_ENABLE_KEYBOARD, |
143 | }; | |
bf36b901 | 144 | #else |
7fffe31d | 145 | #define sysrq_unraw_op (*(const struct sysrq_key_op *)NULL) |
1da177e4 LT |
146 | #endif /* CONFIG_VT */ |
147 | ||
1495cc9d | 148 | static void sysrq_handle_crash(int key) |
86b1ae38 | 149 | { |
8341f2f2 | 150 | /* release the RCU read lock before crashing */ |
984cf355 | 151 | rcu_read_unlock(); |
8341f2f2 MK |
152 | |
153 | panic("sysrq triggered crash\n"); | |
86b1ae38 | 154 | } |
7fffe31d | 155 | static const struct sysrq_key_op sysrq_crash_op = { |
d6580a9f | 156 | .handler = sysrq_handle_crash, |
afa80ccb | 157 | .help_msg = "crash(c)", |
d6580a9f | 158 | .action_msg = "Trigger a crash", |
86b1ae38 HN |
159 | .enable_mask = SYSRQ_ENABLE_DUMP, |
160 | }; | |
86b1ae38 | 161 | |
1495cc9d | 162 | static void sysrq_handle_reboot(int key) |
1da177e4 | 163 | { |
b2e9c7d0 | 164 | lockdep_off(); |
1da177e4 | 165 | local_irq_enable(); |
4de8b9b7 | 166 | emergency_restart(); |
1da177e4 | 167 | } |
7fffe31d | 168 | static const struct sysrq_key_op sysrq_reboot_op = { |
1da177e4 | 169 | .handler = sysrq_handle_reboot, |
afa80ccb | 170 | .help_msg = "reboot(b)", |
1da177e4 LT |
171 | .action_msg = "Resetting", |
172 | .enable_mask = SYSRQ_ENABLE_BOOT, | |
173 | }; | |
174 | ||
7fffe31d | 175 | const struct sysrq_key_op *__sysrq_reboot_op = &sysrq_reboot_op; |
0f1c9688 | 176 | |
1495cc9d | 177 | static void sysrq_handle_sync(int key) |
1da177e4 LT |
178 | { |
179 | emergency_sync(); | |
180 | } | |
7fffe31d | 181 | static const struct sysrq_key_op sysrq_sync_op = { |
1da177e4 | 182 | .handler = sysrq_handle_sync, |
afa80ccb | 183 | .help_msg = "sync(s)", |
1da177e4 LT |
184 | .action_msg = "Emergency Sync", |
185 | .enable_mask = SYSRQ_ENABLE_SYNC, | |
186 | }; | |
187 | ||
1495cc9d | 188 | static void sysrq_handle_show_timers(int key) |
88ad0bf6 IM |
189 | { |
190 | sysrq_timer_list_show(); | |
191 | } | |
192 | ||
7fffe31d | 193 | static const struct sysrq_key_op sysrq_show_timers_op = { |
88ad0bf6 | 194 | .handler = sysrq_handle_show_timers, |
afa80ccb | 195 | .help_msg = "show-all-timers(q)", |
322acf65 | 196 | .action_msg = "Show clockevent devices & pending hrtimers (no others)", |
88ad0bf6 IM |
197 | }; |
198 | ||
1495cc9d | 199 | static void sysrq_handle_mountro(int key) |
1da177e4 LT |
200 | { |
201 | emergency_remount(); | |
202 | } | |
7fffe31d | 203 | static const struct sysrq_key_op sysrq_mountro_op = { |
1da177e4 | 204 | .handler = sysrq_handle_mountro, |
afa80ccb | 205 | .help_msg = "unmount(u)", |
1da177e4 LT |
206 | .action_msg = "Emergency Remount R/O", |
207 | .enable_mask = SYSRQ_ENABLE_REMOUNT, | |
208 | }; | |
209 | ||
8c64580d | 210 | #ifdef CONFIG_LOCKDEP |
1495cc9d | 211 | static void sysrq_handle_showlocks(int key) |
de5097c2 | 212 | { |
9a11b49a | 213 | debug_show_all_locks(); |
de5097c2 | 214 | } |
8c64580d | 215 | |
7fffe31d | 216 | static const struct sysrq_key_op sysrq_showlocks_op = { |
de5097c2 | 217 | .handler = sysrq_handle_showlocks, |
afa80ccb | 218 | .help_msg = "show-all-locks(d)", |
de5097c2 IM |
219 | .action_msg = "Show Locks Held", |
220 | }; | |
bf36b901 | 221 | #else |
7fffe31d | 222 | #define sysrq_showlocks_op (*(const struct sysrq_key_op *)NULL) |
de5097c2 | 223 | #endif |
1da177e4 | 224 | |
5045bcae | 225 | #ifdef CONFIG_SMP |
6ac972dd | 226 | static DEFINE_RAW_SPINLOCK(show_lock); |
5045bcae RR |
227 | |
228 | static void showacpu(void *dummy) | |
229 | { | |
230 | unsigned long flags; | |
231 | ||
232 | /* Idle CPUs have no interesting backtrace. */ | |
233 | if (idle_cpu(smp_processor_id())) | |
234 | return; | |
235 | ||
6ac972dd | 236 | raw_spin_lock_irqsave(&show_lock, flags); |
401e4a7c | 237 | pr_info("CPU%d:\n", smp_processor_id()); |
ab34b46d | 238 | show_stack_loglvl(NULL, NULL, KERN_INFO); |
6ac972dd | 239 | raw_spin_unlock_irqrestore(&show_lock, flags); |
5045bcae RR |
240 | } |
241 | ||
242 | static void sysrq_showregs_othercpus(struct work_struct *dummy) | |
243 | { | |
8b604d52 | 244 | smp_call_function(showacpu, NULL, 0); |
5045bcae RR |
245 | } |
246 | ||
247 | static DECLARE_WORK(sysrq_showallcpus, sysrq_showregs_othercpus); | |
248 | ||
1495cc9d | 249 | static void sysrq_handle_showallcpus(int key) |
5045bcae | 250 | { |
47cab6a7 IM |
251 | /* |
252 | * Fall back to the workqueue based printing if the | |
253 | * backtrace printing did not succeed or the | |
254 | * architecture has no support for it: | |
255 | */ | |
256 | if (!trigger_all_cpu_backtrace()) { | |
b00bebbc | 257 | struct pt_regs *regs = NULL; |
47cab6a7 | 258 | |
b00bebbc JX |
259 | if (in_irq()) |
260 | regs = get_irq_regs(); | |
47cab6a7 | 261 | if (regs) { |
401e4a7c | 262 | pr_info("CPU%d:\n", smp_processor_id()); |
47cab6a7 IM |
263 | show_regs(regs); |
264 | } | |
265 | schedule_work(&sysrq_showallcpus); | |
266 | } | |
5045bcae RR |
267 | } |
268 | ||
7fffe31d | 269 | static const struct sysrq_key_op sysrq_showallcpus_op = { |
5045bcae | 270 | .handler = sysrq_handle_showallcpus, |
afa80ccb | 271 | .help_msg = "show-backtrace-all-active-cpus(l)", |
5045bcae RR |
272 | .action_msg = "Show backtrace of all active CPUs", |
273 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
274 | }; | |
275 | #endif | |
276 | ||
1495cc9d | 277 | static void sysrq_handle_showregs(int key) |
1da177e4 | 278 | { |
b00bebbc JX |
279 | struct pt_regs *regs = NULL; |
280 | ||
281 | if (in_irq()) | |
282 | regs = get_irq_regs(); | |
7d12e780 DH |
283 | if (regs) |
284 | show_regs(regs); | |
cdd6c482 | 285 | perf_event_print_debug(); |
1da177e4 | 286 | } |
7fffe31d | 287 | static const struct sysrq_key_op sysrq_showregs_op = { |
1da177e4 | 288 | .handler = sysrq_handle_showregs, |
afa80ccb | 289 | .help_msg = "show-registers(p)", |
1da177e4 LT |
290 | .action_msg = "Show Regs", |
291 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
292 | }; | |
293 | ||
1495cc9d | 294 | static void sysrq_handle_showstate(int key) |
1da177e4 LT |
295 | { |
296 | show_state(); | |
3494fc30 | 297 | show_workqueue_state(); |
1da177e4 | 298 | } |
7fffe31d | 299 | static const struct sysrq_key_op sysrq_showstate_op = { |
1da177e4 | 300 | .handler = sysrq_handle_showstate, |
afa80ccb | 301 | .help_msg = "show-task-states(t)", |
1da177e4 LT |
302 | .action_msg = "Show State", |
303 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
304 | }; | |
305 | ||
1495cc9d | 306 | static void sysrq_handle_showstate_blocked(int key) |
e59e2ae2 IM |
307 | { |
308 | show_state_filter(TASK_UNINTERRUPTIBLE); | |
309 | } | |
7fffe31d | 310 | static const struct sysrq_key_op sysrq_showstate_blocked_op = { |
e59e2ae2 | 311 | .handler = sysrq_handle_showstate_blocked, |
afa80ccb | 312 | .help_msg = "show-blocked-tasks(w)", |
e59e2ae2 IM |
313 | .action_msg = "Show Blocked State", |
314 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
315 | }; | |
316 | ||
69f698ad PZ |
317 | #ifdef CONFIG_TRACING |
318 | #include <linux/ftrace.h> | |
319 | ||
1495cc9d | 320 | static void sysrq_ftrace_dump(int key) |
69f698ad | 321 | { |
cecbca96 | 322 | ftrace_dump(DUMP_ALL); |
69f698ad | 323 | } |
7fffe31d | 324 | static const struct sysrq_key_op sysrq_ftrace_dump_op = { |
69f698ad | 325 | .handler = sysrq_ftrace_dump, |
afa80ccb | 326 | .help_msg = "dump-ftrace-buffer(z)", |
69f698ad PZ |
327 | .action_msg = "Dump ftrace buffer", |
328 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
329 | }; | |
330 | #else | |
7fffe31d | 331 | #define sysrq_ftrace_dump_op (*(const struct sysrq_key_op *)NULL) |
69f698ad | 332 | #endif |
e59e2ae2 | 333 | |
1495cc9d | 334 | static void sysrq_handle_showmem(int key) |
1da177e4 | 335 | { |
9af744d7 | 336 | show_mem(0, NULL); |
1da177e4 | 337 | } |
7fffe31d | 338 | static const struct sysrq_key_op sysrq_showmem_op = { |
1da177e4 | 339 | .handler = sysrq_handle_showmem, |
afa80ccb | 340 | .help_msg = "show-memory-usage(m)", |
1da177e4 LT |
341 | .action_msg = "Show Memory", |
342 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
343 | }; | |
344 | ||
bf36b901 AM |
345 | /* |
346 | * Signal sysrq helper function. Sends a signal to all user processes. | |
347 | */ | |
1da177e4 LT |
348 | static void send_sig_all(int sig) |
349 | { | |
350 | struct task_struct *p; | |
351 | ||
e502babe | 352 | read_lock(&tasklist_lock); |
1da177e4 | 353 | for_each_process(p) { |
d3a532a9 AV |
354 | if (p->flags & PF_KTHREAD) |
355 | continue; | |
356 | if (is_global_init(p)) | |
357 | continue; | |
358 | ||
b16503ba | 359 | do_send_sig_info(sig, SEND_SIG_PRIV, p, PIDTYPE_MAX); |
1da177e4 | 360 | } |
e502babe | 361 | read_unlock(&tasklist_lock); |
1da177e4 LT |
362 | } |
363 | ||
1495cc9d | 364 | static void sysrq_handle_term(int key) |
1da177e4 LT |
365 | { |
366 | send_sig_all(SIGTERM); | |
a8fe19eb | 367 | console_loglevel = CONSOLE_LOGLEVEL_DEBUG; |
1da177e4 | 368 | } |
7fffe31d | 369 | static const struct sysrq_key_op sysrq_term_op = { |
1da177e4 | 370 | .handler = sysrq_handle_term, |
afa80ccb | 371 | .help_msg = "terminate-all-tasks(e)", |
1da177e4 LT |
372 | .action_msg = "Terminate All Tasks", |
373 | .enable_mask = SYSRQ_ENABLE_SIGNAL, | |
374 | }; | |
375 | ||
65f27f38 | 376 | static void moom_callback(struct work_struct *ignored) |
1da177e4 | 377 | { |
6e0fc46d DR |
378 | const gfp_t gfp_mask = GFP_KERNEL; |
379 | struct oom_control oc = { | |
380 | .zonelist = node_zonelist(first_memory_node, gfp_mask), | |
381 | .nodemask = NULL, | |
2a966b77 | 382 | .memcg = NULL, |
6e0fc46d | 383 | .gfp_mask = gfp_mask, |
54e9e291 | 384 | .order = -1, |
6e0fc46d DR |
385 | }; |
386 | ||
dc56401f | 387 | mutex_lock(&oom_lock); |
6e0fc46d | 388 | if (!out_of_memory(&oc)) |
d75da004 | 389 | pr_info("OOM request ignored. No task eligible\n"); |
dc56401f | 390 | mutex_unlock(&oom_lock); |
1da177e4 LT |
391 | } |
392 | ||
65f27f38 | 393 | static DECLARE_WORK(moom_work, moom_callback); |
1da177e4 | 394 | |
1495cc9d | 395 | static void sysrq_handle_moom(int key) |
1da177e4 LT |
396 | { |
397 | schedule_work(&moom_work); | |
398 | } | |
7fffe31d | 399 | static const struct sysrq_key_op sysrq_moom_op = { |
1da177e4 | 400 | .handler = sysrq_handle_moom, |
afa80ccb | 401 | .help_msg = "memory-full-oom-kill(f)", |
1da177e4 | 402 | .action_msg = "Manual OOM execution", |
b4236f81 | 403 | .enable_mask = SYSRQ_ENABLE_SIGNAL, |
1da177e4 LT |
404 | }; |
405 | ||
c2d75438 | 406 | #ifdef CONFIG_BLOCK |
1495cc9d | 407 | static void sysrq_handle_thaw(int key) |
c2d75438 ES |
408 | { |
409 | emergency_thaw_all(); | |
410 | } | |
7fffe31d | 411 | static const struct sysrq_key_op sysrq_thaw_op = { |
c2d75438 | 412 | .handler = sysrq_handle_thaw, |
afa80ccb | 413 | .help_msg = "thaw-filesystems(j)", |
c2d75438 ES |
414 | .action_msg = "Emergency Thaw of all frozen filesystems", |
415 | .enable_mask = SYSRQ_ENABLE_SIGNAL, | |
416 | }; | |
417 | #endif | |
418 | ||
1495cc9d | 419 | static void sysrq_handle_kill(int key) |
1da177e4 LT |
420 | { |
421 | send_sig_all(SIGKILL); | |
a8fe19eb | 422 | console_loglevel = CONSOLE_LOGLEVEL_DEBUG; |
1da177e4 | 423 | } |
7fffe31d | 424 | static const struct sysrq_key_op sysrq_kill_op = { |
1da177e4 | 425 | .handler = sysrq_handle_kill, |
afa80ccb | 426 | .help_msg = "kill-all-tasks(i)", |
1da177e4 LT |
427 | .action_msg = "Kill All Tasks", |
428 | .enable_mask = SYSRQ_ENABLE_SIGNAL, | |
429 | }; | |
430 | ||
1495cc9d | 431 | static void sysrq_handle_unrt(int key) |
1da177e4 LT |
432 | { |
433 | normalize_rt_tasks(); | |
434 | } | |
7fffe31d | 435 | static const struct sysrq_key_op sysrq_unrt_op = { |
1da177e4 | 436 | .handler = sysrq_handle_unrt, |
afa80ccb | 437 | .help_msg = "nice-all-RT-tasks(n)", |
1da177e4 LT |
438 | .action_msg = "Nice All RT Tasks", |
439 | .enable_mask = SYSRQ_ENABLE_RTNICE, | |
440 | }; | |
441 | ||
442 | /* Key Operations table and lock */ | |
443 | static DEFINE_SPINLOCK(sysrq_key_table_lock); | |
bf36b901 | 444 | |
7fffe31d | 445 | static const struct sysrq_key_op *sysrq_key_table[36] = { |
bf36b901 AM |
446 | &sysrq_loglevel_op, /* 0 */ |
447 | &sysrq_loglevel_op, /* 1 */ | |
448 | &sysrq_loglevel_op, /* 2 */ | |
449 | &sysrq_loglevel_op, /* 3 */ | |
450 | &sysrq_loglevel_op, /* 4 */ | |
451 | &sysrq_loglevel_op, /* 5 */ | |
452 | &sysrq_loglevel_op, /* 6 */ | |
453 | &sysrq_loglevel_op, /* 7 */ | |
454 | &sysrq_loglevel_op, /* 8 */ | |
455 | &sysrq_loglevel_op, /* 9 */ | |
456 | ||
457 | /* | |
d346cce3 RD |
458 | * a: Don't use for system provided sysrqs, it is handled specially on |
459 | * sparc and will never arrive. | |
bf36b901 AM |
460 | */ |
461 | NULL, /* a */ | |
462 | &sysrq_reboot_op, /* b */ | |
5e351410 | 463 | &sysrq_crash_op, /* c */ |
bf36b901 AM |
464 | &sysrq_showlocks_op, /* d */ |
465 | &sysrq_term_op, /* e */ | |
466 | &sysrq_moom_op, /* f */ | |
364b5b7b | 467 | /* g: May be registered for the kernel debugger */ |
bf36b901 | 468 | NULL, /* g */ |
c2d75438 | 469 | NULL, /* h - reserved for help */ |
bf36b901 | 470 | &sysrq_kill_op, /* i */ |
c2d75438 ES |
471 | #ifdef CONFIG_BLOCK |
472 | &sysrq_thaw_op, /* j */ | |
473 | #else | |
bf36b901 | 474 | NULL, /* j */ |
c2d75438 | 475 | #endif |
bf36b901 | 476 | &sysrq_SAK_op, /* k */ |
5045bcae RR |
477 | #ifdef CONFIG_SMP |
478 | &sysrq_showallcpus_op, /* l */ | |
479 | #else | |
bf36b901 | 480 | NULL, /* l */ |
5045bcae | 481 | #endif |
bf36b901 AM |
482 | &sysrq_showmem_op, /* m */ |
483 | &sysrq_unrt_op, /* n */ | |
d346cce3 | 484 | /* o: This will often be registered as 'Off' at init time */ |
bf36b901 AM |
485 | NULL, /* o */ |
486 | &sysrq_showregs_op, /* p */ | |
88ad0bf6 | 487 | &sysrq_show_timers_op, /* q */ |
d346cce3 | 488 | &sysrq_unraw_op, /* r */ |
bf36b901 AM |
489 | &sysrq_sync_op, /* s */ |
490 | &sysrq_showstate_op, /* t */ | |
491 | &sysrq_mountro_op, /* u */ | |
364b5b7b | 492 | /* v: May be registered for frame buffer console restore */ |
bf36b901 | 493 | NULL, /* v */ |
d346cce3 | 494 | &sysrq_showstate_blocked_op, /* w */ |
d1e9a4f5 | 495 | /* x: May be registered on mips for TLB dump */ |
d346cce3 | 496 | /* x: May be registered on ppc/powerpc for xmon */ |
916ca14a | 497 | /* x: May be registered on sparc64 for global PMU dump */ |
d346cce3 | 498 | NULL, /* x */ |
93dae5b7 | 499 | /* y: May be registered on sparc64 for global register dump */ |
bf36b901 | 500 | NULL, /* y */ |
69f698ad | 501 | &sysrq_ftrace_dump_op, /* z */ |
1da177e4 LT |
502 | }; |
503 | ||
504 | /* key2index calculation, -1 on invalid index */ | |
bf36b901 AM |
505 | static int sysrq_key_table_key2index(int key) |
506 | { | |
1da177e4 | 507 | int retval; |
bf36b901 AM |
508 | |
509 | if ((key >= '0') && (key <= '9')) | |
1da177e4 | 510 | retval = key - '0'; |
bf36b901 | 511 | else if ((key >= 'a') && (key <= 'z')) |
1da177e4 | 512 | retval = key + 10 - 'a'; |
bf36b901 | 513 | else |
1da177e4 | 514 | retval = -1; |
1da177e4 LT |
515 | return retval; |
516 | } | |
517 | ||
518 | /* | |
519 | * get and put functions for the table, exposed to modules. | |
520 | */ | |
23cbedf8 | 521 | static const struct sysrq_key_op *__sysrq_get_key_op(int key) |
bf36b901 | 522 | { |
23cbedf8 | 523 | const struct sysrq_key_op *op_p = NULL; |
1da177e4 | 524 | int i; |
bf36b901 | 525 | |
1da177e4 | 526 | i = sysrq_key_table_key2index(key); |
bf36b901 AM |
527 | if (i != -1) |
528 | op_p = sysrq_key_table[i]; | |
97f5f0cd | 529 | |
1da177e4 LT |
530 | return op_p; |
531 | } | |
532 | ||
23cbedf8 | 533 | static void __sysrq_put_key_op(int key, const struct sysrq_key_op *op_p) |
bf36b901 AM |
534 | { |
535 | int i = sysrq_key_table_key2index(key); | |
1da177e4 | 536 | |
1da177e4 LT |
537 | if (i != -1) |
538 | sysrq_key_table[i] = op_p; | |
539 | } | |
540 | ||
f335397d | 541 | void __handle_sysrq(int key, bool check_mask) |
1da177e4 | 542 | { |
23cbedf8 | 543 | const struct sysrq_key_op *op_p; |
1da177e4 | 544 | int orig_log_level; |
c39ea0b9 | 545 | int orig_suppress_printk; |
bf36b901 | 546 | int i; |
1da177e4 | 547 | |
c39ea0b9 FT |
548 | orig_suppress_printk = suppress_printk; |
549 | suppress_printk = 0; | |
550 | ||
722773af | 551 | rcu_sysrq_start(); |
984d74a7 | 552 | rcu_read_lock(); |
fb144adc AW |
553 | /* |
554 | * Raise the apparent loglevel to maximum so that the sysrq header | |
555 | * is shown to provide the user with positive feedback. We do not | |
556 | * simply emit this at KERN_EMERG as that would change message | |
557 | * routing in the consumers of /proc/kmsg. | |
558 | */ | |
1da177e4 | 559 | orig_log_level = console_loglevel; |
a8fe19eb | 560 | console_loglevel = CONSOLE_LOGLEVEL_DEFAULT; |
1da177e4 LT |
561 | |
562 | op_p = __sysrq_get_key_op(key); | |
563 | if (op_p) { | |
bf36b901 AM |
564 | /* |
565 | * Should we check for enabled operations (/proc/sysrq-trigger | |
566 | * should not) and is the invoked operation enabled? | |
567 | */ | |
5d6f647f | 568 | if (!check_mask || sysrq_on_mask(op_p->enable_mask)) { |
c3fee609 | 569 | pr_info("%s\n", op_p->action_msg); |
1da177e4 | 570 | console_loglevel = orig_log_level; |
1495cc9d | 571 | op_p->handler(key); |
bf36b901 | 572 | } else { |
c3fee609 | 573 | pr_info("This sysrq operation is disabled.\n"); |
075e1a0c | 574 | console_loglevel = orig_log_level; |
bf36b901 | 575 | } |
1da177e4 | 576 | } else { |
c3fee609 | 577 | pr_info("HELP : "); |
1da177e4 | 578 | /* Only print the help msg once per handler */ |
bf36b901 AM |
579 | for (i = 0; i < ARRAY_SIZE(sysrq_key_table); i++) { |
580 | if (sysrq_key_table[i]) { | |
581 | int j; | |
582 | ||
583 | for (j = 0; sysrq_key_table[i] != | |
584 | sysrq_key_table[j]; j++) | |
585 | ; | |
586 | if (j != i) | |
587 | continue; | |
401e4a7c | 588 | pr_cont("%s ", sysrq_key_table[i]->help_msg); |
bf36b901 | 589 | } |
1da177e4 | 590 | } |
401e4a7c | 591 | pr_cont("\n"); |
1da177e4 LT |
592 | console_loglevel = orig_log_level; |
593 | } | |
984d74a7 | 594 | rcu_read_unlock(); |
722773af | 595 | rcu_sysrq_end(); |
c39ea0b9 FT |
596 | |
597 | suppress_printk = orig_suppress_printk; | |
1da177e4 LT |
598 | } |
599 | ||
f335397d | 600 | void handle_sysrq(int key) |
1da177e4 | 601 | { |
5d6f647f | 602 | if (sysrq_on()) |
f335397d | 603 | __handle_sysrq(key, true); |
1da177e4 | 604 | } |
bf36b901 | 605 | EXPORT_SYMBOL(handle_sysrq); |
1da177e4 | 606 | |
97f5f0cd | 607 | #ifdef CONFIG_INPUT |
ffb6e0c9 | 608 | static int sysrq_reset_downtime_ms; |
97f5f0cd DT |
609 | |
610 | /* Simple translation table for the SysRq keys */ | |
fcb71930 | 611 | static const unsigned char sysrq_xlate[KEY_CNT] = |
97f5f0cd DT |
612 | "\000\0331234567890-=\177\t" /* 0x00 - 0x0f */ |
613 | "qwertyuiop[]\r\000as" /* 0x10 - 0x1f */ | |
614 | "dfghjkl;'`\000\\zxcv" /* 0x20 - 0x2f */ | |
615 | "bnm,./\000*\000 \000\201\202\203\204\205" /* 0x30 - 0x3f */ | |
616 | "\206\207\210\211\212\000\000789-456+1" /* 0x40 - 0x4f */ | |
617 | "230\177\000\000\213\214\000\000\000\000\000\000\000\000\000\000" /* 0x50 - 0x5f */ | |
618 | "\r\000/"; /* 0x60 - 0x6f */ | |
619 | ||
fcb71930 DT |
620 | struct sysrq_state { |
621 | struct input_handle handle; | |
622 | struct work_struct reinject_work; | |
623 | unsigned long key_down[BITS_TO_LONGS(KEY_CNT)]; | |
624 | unsigned int alt; | |
625 | unsigned int alt_use; | |
626 | bool active; | |
627 | bool need_reinject; | |
7ab7b5ad | 628 | bool reinjecting; |
154b7a48 MP |
629 | |
630 | /* reset sequence handling */ | |
631 | bool reset_canceled; | |
3d289517 | 632 | bool reset_requested; |
154b7a48 MP |
633 | unsigned long reset_keybit[BITS_TO_LONGS(KEY_CNT)]; |
634 | int reset_seq_len; | |
635 | int reset_seq_cnt; | |
636 | int reset_seq_version; | |
39030786 | 637 | struct timer_list keyreset_timer; |
fcb71930 DT |
638 | }; |
639 | ||
154b7a48 MP |
640 | #define SYSRQ_KEY_RESET_MAX 20 /* Should be plenty */ |
641 | static unsigned short sysrq_reset_seq[SYSRQ_KEY_RESET_MAX]; | |
642 | static unsigned int sysrq_reset_seq_len; | |
643 | static unsigned int sysrq_reset_seq_version = 1; | |
644 | ||
645 | static void sysrq_parse_reset_sequence(struct sysrq_state *state) | |
646 | { | |
647 | int i; | |
648 | unsigned short key; | |
649 | ||
650 | state->reset_seq_cnt = 0; | |
651 | ||
652 | for (i = 0; i < sysrq_reset_seq_len; i++) { | |
653 | key = sysrq_reset_seq[i]; | |
654 | ||
655 | if (key == KEY_RESERVED || key > KEY_MAX) | |
656 | break; | |
657 | ||
658 | __set_bit(key, state->reset_keybit); | |
659 | state->reset_seq_len++; | |
660 | ||
661 | if (test_bit(key, state->key_down)) | |
662 | state->reset_seq_cnt++; | |
663 | } | |
664 | ||
665 | /* Disable reset until old keys are not released */ | |
666 | state->reset_canceled = state->reset_seq_cnt != 0; | |
667 | ||
668 | state->reset_seq_version = sysrq_reset_seq_version; | |
669 | } | |
670 | ||
8c318fa9 | 671 | static void sysrq_do_reset(struct timer_list *t) |
39030786 | 672 | { |
8c318fa9 | 673 | struct sysrq_state *state = from_timer(state, t, keyreset_timer); |
3d289517 MP |
674 | |
675 | state->reset_requested = true; | |
676 | ||
8fefbc6d | 677 | orderly_reboot(); |
39030786 MP |
678 | } |
679 | ||
680 | static void sysrq_handle_reset_request(struct sysrq_state *state) | |
681 | { | |
3d289517 MP |
682 | if (state->reset_requested) |
683 | __handle_sysrq(sysrq_xlate[KEY_B], false); | |
684 | ||
39030786 MP |
685 | if (sysrq_reset_downtime_ms) |
686 | mod_timer(&state->keyreset_timer, | |
687 | jiffies + msecs_to_jiffies(sysrq_reset_downtime_ms)); | |
688 | else | |
8c318fa9 | 689 | sysrq_do_reset(&state->keyreset_timer); |
39030786 MP |
690 | } |
691 | ||
692 | static void sysrq_detect_reset_sequence(struct sysrq_state *state, | |
154b7a48 MP |
693 | unsigned int code, int value) |
694 | { | |
695 | if (!test_bit(code, state->reset_keybit)) { | |
696 | /* | |
697 | * Pressing any key _not_ in reset sequence cancels | |
39030786 MP |
698 | * the reset sequence. Also cancelling the timer in |
699 | * case additional keys were pressed after a reset | |
700 | * has been requested. | |
154b7a48 | 701 | */ |
39030786 | 702 | if (value && state->reset_seq_cnt) { |
154b7a48 | 703 | state->reset_canceled = true; |
39030786 MP |
704 | del_timer(&state->keyreset_timer); |
705 | } | |
154b7a48 | 706 | } else if (value == 0) { |
39030786 MP |
707 | /* |
708 | * Key release - all keys in the reset sequence need | |
709 | * to be pressed and held for the reset timeout | |
710 | * to hold. | |
711 | */ | |
712 | del_timer(&state->keyreset_timer); | |
713 | ||
154b7a48 MP |
714 | if (--state->reset_seq_cnt == 0) |
715 | state->reset_canceled = false; | |
716 | } else if (value == 1) { | |
717 | /* key press, not autorepeat */ | |
718 | if (++state->reset_seq_cnt == state->reset_seq_len && | |
719 | !state->reset_canceled) { | |
39030786 | 720 | sysrq_handle_reset_request(state); |
154b7a48 MP |
721 | } |
722 | } | |
154b7a48 MP |
723 | } |
724 | ||
4c076eb0 MP |
725 | #ifdef CONFIG_OF |
726 | static void sysrq_of_get_keyreset_config(void) | |
727 | { | |
728 | u32 key; | |
729 | struct device_node *np; | |
730 | struct property *prop; | |
731 | const __be32 *p; | |
732 | ||
733 | np = of_find_node_by_path("/chosen/linux,sysrq-reset-seq"); | |
734 | if (!np) { | |
735 | pr_debug("No sysrq node found"); | |
736 | return; | |
737 | } | |
738 | ||
739 | /* Reset in case a __weak definition was present */ | |
740 | sysrq_reset_seq_len = 0; | |
741 | ||
742 | of_property_for_each_u32(np, "keyset", prop, p, key) { | |
743 | if (key == KEY_RESERVED || key > KEY_MAX || | |
744 | sysrq_reset_seq_len == SYSRQ_KEY_RESET_MAX) | |
745 | break; | |
746 | ||
747 | sysrq_reset_seq[sysrq_reset_seq_len++] = (unsigned short)key; | |
748 | } | |
749 | ||
750 | /* Get reset timeout if any. */ | |
751 | of_property_read_u32(np, "timeout-ms", &sysrq_reset_downtime_ms); | |
279070b9 YL |
752 | |
753 | of_node_put(np); | |
4c076eb0 MP |
754 | } |
755 | #else | |
756 | static void sysrq_of_get_keyreset_config(void) | |
757 | { | |
758 | } | |
759 | #endif | |
760 | ||
fcb71930 DT |
761 | static void sysrq_reinject_alt_sysrq(struct work_struct *work) |
762 | { | |
763 | struct sysrq_state *sysrq = | |
764 | container_of(work, struct sysrq_state, reinject_work); | |
765 | struct input_handle *handle = &sysrq->handle; | |
766 | unsigned int alt_code = sysrq->alt_use; | |
767 | ||
768 | if (sysrq->need_reinject) { | |
7ab7b5ad DT |
769 | /* we do not want the assignment to be reordered */ |
770 | sysrq->reinjecting = true; | |
771 | mb(); | |
772 | ||
fcb71930 DT |
773 | /* Simulate press and release of Alt + SysRq */ |
774 | input_inject_event(handle, EV_KEY, alt_code, 1); | |
775 | input_inject_event(handle, EV_KEY, KEY_SYSRQ, 1); | |
776 | input_inject_event(handle, EV_SYN, SYN_REPORT, 1); | |
777 | ||
778 | input_inject_event(handle, EV_KEY, KEY_SYSRQ, 0); | |
779 | input_inject_event(handle, EV_KEY, alt_code, 0); | |
780 | input_inject_event(handle, EV_SYN, SYN_REPORT, 1); | |
7ab7b5ad DT |
781 | |
782 | mb(); | |
783 | sysrq->reinjecting = false; | |
fcb71930 DT |
784 | } |
785 | } | |
97f5f0cd | 786 | |
154b7a48 MP |
787 | static bool sysrq_handle_keypress(struct sysrq_state *sysrq, |
788 | unsigned int code, int value) | |
97f5f0cd | 789 | { |
fcb71930 | 790 | bool was_active = sysrq->active; |
1966cb22 DT |
791 | bool suppress; |
792 | ||
154b7a48 | 793 | switch (code) { |
7ab7b5ad | 794 | |
154b7a48 MP |
795 | case KEY_LEFTALT: |
796 | case KEY_RIGHTALT: | |
797 | if (!value) { | |
798 | /* One of ALTs is being released */ | |
799 | if (sysrq->active && code == sysrq->alt_use) | |
800 | sysrq->active = false; | |
1966cb22 | 801 | |
154b7a48 MP |
802 | sysrq->alt = KEY_RESERVED; |
803 | ||
804 | } else if (value != 2) { | |
805 | sysrq->alt = code; | |
806 | sysrq->need_reinject = false; | |
807 | } | |
fcb71930 | 808 | break; |
97f5f0cd | 809 | |
154b7a48 MP |
810 | case KEY_SYSRQ: |
811 | if (value == 1 && sysrq->alt != KEY_RESERVED) { | |
812 | sysrq->active = true; | |
813 | sysrq->alt_use = sysrq->alt; | |
814 | /* | |
815 | * If nothing else will be pressed we'll need | |
816 | * to re-inject Alt-SysRq keysroke. | |
817 | */ | |
818 | sysrq->need_reinject = true; | |
819 | } | |
97f5f0cd | 820 | |
154b7a48 MP |
821 | /* |
822 | * Pretend that sysrq was never pressed at all. This | |
823 | * is needed to properly handle KGDB which will try | |
824 | * to release all keys after exiting debugger. If we | |
825 | * do not clear key bit it KGDB will end up sending | |
826 | * release events for Alt and SysRq, potentially | |
827 | * triggering print screen function. | |
828 | */ | |
829 | if (sysrq->active) | |
830 | clear_bit(KEY_SYSRQ, sysrq->handle.dev->key); | |
f5dec511 | 831 | |
154b7a48 | 832 | break; |
fcb71930 | 833 | |
154b7a48 MP |
834 | default: |
835 | if (sysrq->active && value && value != 2) { | |
836 | sysrq->need_reinject = false; | |
837 | __handle_sysrq(sysrq_xlate[code], true); | |
838 | } | |
839 | break; | |
840 | } | |
fcb71930 | 841 | |
154b7a48 | 842 | suppress = sysrq->active; |
fcb71930 | 843 | |
154b7a48 | 844 | if (!sysrq->active) { |
fcb71930 | 845 | |
154b7a48 MP |
846 | /* |
847 | * See if reset sequence has changed since the last time. | |
848 | */ | |
849 | if (sysrq->reset_seq_version != sysrq_reset_seq_version) | |
850 | sysrq_parse_reset_sequence(sysrq); | |
fcb71930 | 851 | |
154b7a48 MP |
852 | /* |
853 | * If we are not suppressing key presses keep track of | |
854 | * keyboard state so we can release keys that have been | |
855 | * pressed before entering SysRq mode. | |
856 | */ | |
857 | if (value) | |
858 | set_bit(code, sysrq->key_down); | |
859 | else | |
860 | clear_bit(code, sysrq->key_down); | |
861 | ||
862 | if (was_active) | |
863 | schedule_work(&sysrq->reinject_work); | |
864 | ||
39030786 MP |
865 | /* Check for reset sequence */ |
866 | sysrq_detect_reset_sequence(sysrq, code, value); | |
97f5f0cd | 867 | |
154b7a48 MP |
868 | } else if (value == 0 && test_and_clear_bit(code, sysrq->key_down)) { |
869 | /* | |
870 | * Pass on release events for keys that was pressed before | |
871 | * entering SysRq mode. | |
872 | */ | |
873 | suppress = false; | |
874 | } | |
fcb71930 | 875 | |
154b7a48 MP |
876 | return suppress; |
877 | } | |
fcb71930 | 878 | |
154b7a48 MP |
879 | static bool sysrq_filter(struct input_handle *handle, |
880 | unsigned int type, unsigned int code, int value) | |
881 | { | |
882 | struct sysrq_state *sysrq = handle->private; | |
883 | bool suppress; | |
fcb71930 | 884 | |
154b7a48 MP |
885 | /* |
886 | * Do not filter anything if we are in the process of re-injecting | |
887 | * Alt+SysRq combination. | |
888 | */ | |
889 | if (sysrq->reinjecting) | |
890 | return false; | |
891 | ||
892 | switch (type) { | |
893 | ||
894 | case EV_SYN: | |
895 | suppress = false; | |
896 | break; | |
897 | ||
898 | case EV_KEY: | |
899 | suppress = sysrq_handle_keypress(sysrq, code, value); | |
97f5f0cd DT |
900 | break; |
901 | ||
902 | default: | |
fcb71930 | 903 | suppress = sysrq->active; |
97f5f0cd DT |
904 | break; |
905 | } | |
906 | ||
1966cb22 | 907 | return suppress; |
97f5f0cd DT |
908 | } |
909 | ||
910 | static int sysrq_connect(struct input_handler *handler, | |
911 | struct input_dev *dev, | |
912 | const struct input_device_id *id) | |
913 | { | |
fcb71930 | 914 | struct sysrq_state *sysrq; |
97f5f0cd DT |
915 | int error; |
916 | ||
fcb71930 DT |
917 | sysrq = kzalloc(sizeof(struct sysrq_state), GFP_KERNEL); |
918 | if (!sysrq) | |
97f5f0cd DT |
919 | return -ENOMEM; |
920 | ||
fcb71930 DT |
921 | INIT_WORK(&sysrq->reinject_work, sysrq_reinject_alt_sysrq); |
922 | ||
923 | sysrq->handle.dev = dev; | |
924 | sysrq->handle.handler = handler; | |
925 | sysrq->handle.name = "sysrq"; | |
926 | sysrq->handle.private = sysrq; | |
8c318fa9 | 927 | timer_setup(&sysrq->keyreset_timer, sysrq_do_reset, 0); |
97f5f0cd | 928 | |
fcb71930 | 929 | error = input_register_handle(&sysrq->handle); |
97f5f0cd DT |
930 | if (error) { |
931 | pr_err("Failed to register input sysrq handler, error %d\n", | |
932 | error); | |
933 | goto err_free; | |
934 | } | |
935 | ||
fcb71930 | 936 | error = input_open_device(&sysrq->handle); |
97f5f0cd DT |
937 | if (error) { |
938 | pr_err("Failed to open input device, error %d\n", error); | |
939 | goto err_unregister; | |
940 | } | |
941 | ||
942 | return 0; | |
943 | ||
944 | err_unregister: | |
fcb71930 | 945 | input_unregister_handle(&sysrq->handle); |
97f5f0cd | 946 | err_free: |
fcb71930 | 947 | kfree(sysrq); |
97f5f0cd DT |
948 | return error; |
949 | } | |
950 | ||
951 | static void sysrq_disconnect(struct input_handle *handle) | |
952 | { | |
fcb71930 DT |
953 | struct sysrq_state *sysrq = handle->private; |
954 | ||
97f5f0cd | 955 | input_close_device(handle); |
fcb71930 | 956 | cancel_work_sync(&sysrq->reinject_work); |
39030786 | 957 | del_timer_sync(&sysrq->keyreset_timer); |
97f5f0cd | 958 | input_unregister_handle(handle); |
fcb71930 | 959 | kfree(sysrq); |
97f5f0cd DT |
960 | } |
961 | ||
962 | /* | |
1966cb22 DT |
963 | * We are matching on KEY_LEFTALT instead of KEY_SYSRQ because not all |
964 | * keyboards have SysRq key predefined and so user may add it to keymap | |
97f5f0cd DT |
965 | * later, but we expect all such keyboards to have left alt. |
966 | */ | |
967 | static const struct input_device_id sysrq_ids[] = { | |
968 | { | |
969 | .flags = INPUT_DEVICE_ID_MATCH_EVBIT | | |
970 | INPUT_DEVICE_ID_MATCH_KEYBIT, | |
802c0388 AM |
971 | .evbit = { [BIT_WORD(EV_KEY)] = BIT_MASK(EV_KEY) }, |
972 | .keybit = { [BIT_WORD(KEY_LEFTALT)] = BIT_MASK(KEY_LEFTALT) }, | |
97f5f0cd DT |
973 | }, |
974 | { }, | |
975 | }; | |
976 | ||
977 | static struct input_handler sysrq_handler = { | |
978 | .filter = sysrq_filter, | |
979 | .connect = sysrq_connect, | |
980 | .disconnect = sysrq_disconnect, | |
981 | .name = "sysrq", | |
982 | .id_table = sysrq_ids, | |
983 | }; | |
984 | ||
97f5f0cd DT |
985 | static inline void sysrq_register_handler(void) |
986 | { | |
987 | int error; | |
988 | ||
4c076eb0 MP |
989 | sysrq_of_get_keyreset_config(); |
990 | ||
97f5f0cd DT |
991 | error = input_register_handler(&sysrq_handler); |
992 | if (error) | |
993 | pr_err("Failed to register input handler, error %d", error); | |
97f5f0cd DT |
994 | } |
995 | ||
996 | static inline void sysrq_unregister_handler(void) | |
997 | { | |
f06327d1 | 998 | input_unregister_handler(&sysrq_handler); |
97f5f0cd DT |
999 | } |
1000 | ||
154b7a48 MP |
1001 | static int sysrq_reset_seq_param_set(const char *buffer, |
1002 | const struct kernel_param *kp) | |
1003 | { | |
1004 | unsigned long val; | |
1005 | int error; | |
1006 | ||
86b40567 | 1007 | error = kstrtoul(buffer, 0, &val); |
154b7a48 MP |
1008 | if (error < 0) |
1009 | return error; | |
1010 | ||
1011 | if (val > KEY_MAX) | |
1012 | return -EINVAL; | |
1013 | ||
1014 | *((unsigned short *)kp->arg) = val; | |
1015 | sysrq_reset_seq_version++; | |
1016 | ||
1017 | return 0; | |
1018 | } | |
1019 | ||
9c27847d | 1020 | static const struct kernel_param_ops param_ops_sysrq_reset_seq = { |
154b7a48 MP |
1021 | .get = param_get_ushort, |
1022 | .set = sysrq_reset_seq_param_set, | |
1023 | }; | |
1024 | ||
1025 | #define param_check_sysrq_reset_seq(name, p) \ | |
1026 | __param_check(name, p, unsigned short) | |
1027 | ||
3bce6f64 PG |
1028 | /* |
1029 | * not really modular, but the easiest way to keep compat with existing | |
1030 | * bootargs behaviour is to continue using module_param here. | |
1031 | */ | |
154b7a48 MP |
1032 | module_param_array_named(reset_seq, sysrq_reset_seq, sysrq_reset_seq, |
1033 | &sysrq_reset_seq_len, 0644); | |
1034 | ||
39030786 MP |
1035 | module_param_named(sysrq_downtime_ms, sysrq_reset_downtime_ms, int, 0644); |
1036 | ||
97f5f0cd DT |
1037 | #else |
1038 | ||
1039 | static inline void sysrq_register_handler(void) | |
1040 | { | |
1041 | } | |
1042 | ||
1043 | static inline void sysrq_unregister_handler(void) | |
1044 | { | |
1045 | } | |
1046 | ||
1047 | #endif /* CONFIG_INPUT */ | |
1048 | ||
1049 | int sysrq_toggle_support(int enable_mask) | |
1050 | { | |
1051 | bool was_enabled = sysrq_on(); | |
1052 | ||
1053 | sysrq_enabled = enable_mask; | |
1054 | ||
1055 | if (was_enabled != sysrq_on()) { | |
1056 | if (sysrq_on()) | |
1057 | sysrq_register_handler(); | |
1058 | else | |
1059 | sysrq_unregister_handler(); | |
1060 | } | |
1061 | ||
1062 | return 0; | |
1063 | } | |
66bb1c95 | 1064 | EXPORT_SYMBOL_GPL(sysrq_toggle_support); |
97f5f0cd | 1065 | |
23cbedf8 EV |
1066 | static int __sysrq_swap_key_ops(int key, const struct sysrq_key_op *insert_op_p, |
1067 | const struct sysrq_key_op *remove_op_p) | |
bf36b901 | 1068 | { |
1da177e4 | 1069 | int retval; |
1da177e4 | 1070 | |
984d74a7 | 1071 | spin_lock(&sysrq_key_table_lock); |
1da177e4 LT |
1072 | if (__sysrq_get_key_op(key) == remove_op_p) { |
1073 | __sysrq_put_key_op(key, insert_op_p); | |
1074 | retval = 0; | |
1075 | } else { | |
1076 | retval = -1; | |
1077 | } | |
984d74a7 RR |
1078 | spin_unlock(&sysrq_key_table_lock); |
1079 | ||
1080 | /* | |
1081 | * A concurrent __handle_sysrq either got the old op or the new op. | |
1082 | * Wait for it to go away before returning, so the code for an old | |
1083 | * op is not freed (eg. on module unload) while it is in use. | |
1084 | */ | |
1085 | synchronize_rcu(); | |
1086 | ||
1da177e4 LT |
1087 | return retval; |
1088 | } | |
1089 | ||
23cbedf8 | 1090 | int register_sysrq_key(int key, const struct sysrq_key_op *op_p) |
1da177e4 LT |
1091 | { |
1092 | return __sysrq_swap_key_ops(key, op_p, NULL); | |
1093 | } | |
bf36b901 | 1094 | EXPORT_SYMBOL(register_sysrq_key); |
1da177e4 | 1095 | |
23cbedf8 | 1096 | int unregister_sysrq_key(int key, const struct sysrq_key_op *op_p) |
1da177e4 LT |
1097 | { |
1098 | return __sysrq_swap_key_ops(key, NULL, op_p); | |
1099 | } | |
1da177e4 | 1100 | EXPORT_SYMBOL(unregister_sysrq_key); |
f40cbaa5 AD |
1101 | |
1102 | #ifdef CONFIG_PROC_FS | |
1103 | /* | |
1104 | * writing 'C' to /proc/sysrq-trigger is like sysrq-C | |
1105 | */ | |
1106 | static ssize_t write_sysrq_trigger(struct file *file, const char __user *buf, | |
1107 | size_t count, loff_t *ppos) | |
1108 | { | |
1109 | if (count) { | |
1110 | char c; | |
1111 | ||
1112 | if (get_user(c, buf)) | |
1113 | return -EFAULT; | |
f335397d | 1114 | __handle_sysrq(c, false); |
f40cbaa5 | 1115 | } |
97f5f0cd | 1116 | |
f40cbaa5 AD |
1117 | return count; |
1118 | } | |
1119 | ||
97a32539 AD |
1120 | static const struct proc_ops sysrq_trigger_proc_ops = { |
1121 | .proc_write = write_sysrq_trigger, | |
1122 | .proc_lseek = noop_llseek, | |
f40cbaa5 AD |
1123 | }; |
1124 | ||
97f5f0cd DT |
1125 | static void sysrq_init_procfs(void) |
1126 | { | |
1127 | if (!proc_create("sysrq-trigger", S_IWUSR, NULL, | |
97a32539 | 1128 | &sysrq_trigger_proc_ops)) |
97f5f0cd DT |
1129 | pr_err("Failed to register proc interface\n"); |
1130 | } | |
1131 | ||
1132 | #else | |
1133 | ||
1134 | static inline void sysrq_init_procfs(void) | |
1135 | { | |
1136 | } | |
1137 | ||
1138 | #endif /* CONFIG_PROC_FS */ | |
1139 | ||
f40cbaa5 AD |
1140 | static int __init sysrq_init(void) |
1141 | { | |
97f5f0cd DT |
1142 | sysrq_init_procfs(); |
1143 | ||
1144 | if (sysrq_on()) | |
1145 | sysrq_register_handler(); | |
1146 | ||
f40cbaa5 AD |
1147 | return 0; |
1148 | } | |
3bce6f64 | 1149 | device_initcall(sysrq_init); |