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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; |
8b6312f4 | 121 | schedule_work(SAK_work); |
1da177e4 | 122 | } |
7fffe31d | 123 | static const struct sysrq_key_op sysrq_SAK_op = { |
1da177e4 | 124 | .handler = sysrq_handle_SAK, |
afa80ccb | 125 | .help_msg = "sak(k)", |
1da177e4 LT |
126 | .action_msg = "SAK", |
127 | .enable_mask = SYSRQ_ENABLE_KEYBOARD, | |
128 | }; | |
bf36b901 | 129 | #else |
7fffe31d | 130 | #define sysrq_SAK_op (*(const struct sysrq_key_op *)NULL) |
1da177e4 LT |
131 | #endif |
132 | ||
133 | #ifdef CONFIG_VT | |
1495cc9d | 134 | static void sysrq_handle_unraw(int key) |
1da177e4 | 135 | { |
079c9534 | 136 | vt_reset_unicode(fg_console); |
1da177e4 | 137 | } |
079c9534 | 138 | |
7fffe31d | 139 | static const struct sysrq_key_op sysrq_unraw_op = { |
1da177e4 | 140 | .handler = sysrq_handle_unraw, |
afa80ccb | 141 | .help_msg = "unraw(r)", |
2e8ecb9d | 142 | .action_msg = "Keyboard mode set to system default", |
1da177e4 LT |
143 | .enable_mask = SYSRQ_ENABLE_KEYBOARD, |
144 | }; | |
bf36b901 | 145 | #else |
7fffe31d | 146 | #define sysrq_unraw_op (*(const struct sysrq_key_op *)NULL) |
1da177e4 LT |
147 | #endif /* CONFIG_VT */ |
148 | ||
1495cc9d | 149 | static void sysrq_handle_crash(int key) |
86b1ae38 | 150 | { |
8341f2f2 | 151 | /* release the RCU read lock before crashing */ |
984cf355 | 152 | rcu_read_unlock(); |
8341f2f2 MK |
153 | |
154 | panic("sysrq triggered crash\n"); | |
86b1ae38 | 155 | } |
7fffe31d | 156 | static const struct sysrq_key_op sysrq_crash_op = { |
d6580a9f | 157 | .handler = sysrq_handle_crash, |
afa80ccb | 158 | .help_msg = "crash(c)", |
d6580a9f | 159 | .action_msg = "Trigger a crash", |
86b1ae38 HN |
160 | .enable_mask = SYSRQ_ENABLE_DUMP, |
161 | }; | |
86b1ae38 | 162 | |
1495cc9d | 163 | static void sysrq_handle_reboot(int key) |
1da177e4 | 164 | { |
b2e9c7d0 | 165 | lockdep_off(); |
1da177e4 | 166 | local_irq_enable(); |
4de8b9b7 | 167 | emergency_restart(); |
1da177e4 | 168 | } |
7fffe31d | 169 | static const struct sysrq_key_op sysrq_reboot_op = { |
1da177e4 | 170 | .handler = sysrq_handle_reboot, |
afa80ccb | 171 | .help_msg = "reboot(b)", |
1da177e4 LT |
172 | .action_msg = "Resetting", |
173 | .enable_mask = SYSRQ_ENABLE_BOOT, | |
174 | }; | |
175 | ||
7fffe31d | 176 | const struct sysrq_key_op *__sysrq_reboot_op = &sysrq_reboot_op; |
0f1c9688 | 177 | |
1495cc9d | 178 | static void sysrq_handle_sync(int key) |
1da177e4 LT |
179 | { |
180 | emergency_sync(); | |
181 | } | |
7fffe31d | 182 | static const struct sysrq_key_op sysrq_sync_op = { |
1da177e4 | 183 | .handler = sysrq_handle_sync, |
afa80ccb | 184 | .help_msg = "sync(s)", |
1da177e4 LT |
185 | .action_msg = "Emergency Sync", |
186 | .enable_mask = SYSRQ_ENABLE_SYNC, | |
187 | }; | |
188 | ||
1495cc9d | 189 | static void sysrq_handle_show_timers(int key) |
88ad0bf6 IM |
190 | { |
191 | sysrq_timer_list_show(); | |
192 | } | |
193 | ||
7fffe31d | 194 | static const struct sysrq_key_op sysrq_show_timers_op = { |
88ad0bf6 | 195 | .handler = sysrq_handle_show_timers, |
afa80ccb | 196 | .help_msg = "show-all-timers(q)", |
322acf65 | 197 | .action_msg = "Show clockevent devices & pending hrtimers (no others)", |
88ad0bf6 IM |
198 | }; |
199 | ||
1495cc9d | 200 | static void sysrq_handle_mountro(int key) |
1da177e4 LT |
201 | { |
202 | emergency_remount(); | |
203 | } | |
7fffe31d | 204 | static const struct sysrq_key_op sysrq_mountro_op = { |
1da177e4 | 205 | .handler = sysrq_handle_mountro, |
afa80ccb | 206 | .help_msg = "unmount(u)", |
1da177e4 LT |
207 | .action_msg = "Emergency Remount R/O", |
208 | .enable_mask = SYSRQ_ENABLE_REMOUNT, | |
209 | }; | |
210 | ||
8c64580d | 211 | #ifdef CONFIG_LOCKDEP |
1495cc9d | 212 | static void sysrq_handle_showlocks(int key) |
de5097c2 | 213 | { |
9a11b49a | 214 | debug_show_all_locks(); |
de5097c2 | 215 | } |
8c64580d | 216 | |
7fffe31d | 217 | static const struct sysrq_key_op sysrq_showlocks_op = { |
de5097c2 | 218 | .handler = sysrq_handle_showlocks, |
afa80ccb | 219 | .help_msg = "show-all-locks(d)", |
de5097c2 IM |
220 | .action_msg = "Show Locks Held", |
221 | }; | |
bf36b901 | 222 | #else |
7fffe31d | 223 | #define sysrq_showlocks_op (*(const struct sysrq_key_op *)NULL) |
de5097c2 | 224 | #endif |
1da177e4 | 225 | |
5045bcae | 226 | #ifdef CONFIG_SMP |
6ac972dd | 227 | static DEFINE_RAW_SPINLOCK(show_lock); |
5045bcae RR |
228 | |
229 | static void showacpu(void *dummy) | |
230 | { | |
231 | unsigned long flags; | |
232 | ||
233 | /* Idle CPUs have no interesting backtrace. */ | |
234 | if (idle_cpu(smp_processor_id())) | |
235 | return; | |
236 | ||
6ac972dd | 237 | raw_spin_lock_irqsave(&show_lock, flags); |
401e4a7c | 238 | pr_info("CPU%d:\n", smp_processor_id()); |
9cb8f069 | 239 | show_stack(NULL, NULL, KERN_INFO); |
6ac972dd | 240 | raw_spin_unlock_irqrestore(&show_lock, flags); |
5045bcae RR |
241 | } |
242 | ||
243 | static void sysrq_showregs_othercpus(struct work_struct *dummy) | |
244 | { | |
8b604d52 | 245 | smp_call_function(showacpu, NULL, 0); |
5045bcae RR |
246 | } |
247 | ||
248 | static DECLARE_WORK(sysrq_showallcpus, sysrq_showregs_othercpus); | |
249 | ||
1495cc9d | 250 | static void sysrq_handle_showallcpus(int key) |
5045bcae | 251 | { |
47cab6a7 IM |
252 | /* |
253 | * Fall back to the workqueue based printing if the | |
254 | * backtrace printing did not succeed or the | |
255 | * architecture has no support for it: | |
256 | */ | |
257 | if (!trigger_all_cpu_backtrace()) { | |
b00bebbc | 258 | struct pt_regs *regs = NULL; |
47cab6a7 | 259 | |
b00bebbc JX |
260 | if (in_irq()) |
261 | regs = get_irq_regs(); | |
47cab6a7 | 262 | if (regs) { |
401e4a7c | 263 | pr_info("CPU%d:\n", smp_processor_id()); |
47cab6a7 IM |
264 | show_regs(regs); |
265 | } | |
266 | schedule_work(&sysrq_showallcpus); | |
267 | } | |
5045bcae RR |
268 | } |
269 | ||
7fffe31d | 270 | static const struct sysrq_key_op sysrq_showallcpus_op = { |
5045bcae | 271 | .handler = sysrq_handle_showallcpus, |
afa80ccb | 272 | .help_msg = "show-backtrace-all-active-cpus(l)", |
5045bcae RR |
273 | .action_msg = "Show backtrace of all active CPUs", |
274 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
275 | }; | |
276 | #endif | |
277 | ||
1495cc9d | 278 | static void sysrq_handle_showregs(int key) |
1da177e4 | 279 | { |
b00bebbc JX |
280 | struct pt_regs *regs = NULL; |
281 | ||
282 | if (in_irq()) | |
283 | regs = get_irq_regs(); | |
7d12e780 DH |
284 | if (regs) |
285 | show_regs(regs); | |
cdd6c482 | 286 | perf_event_print_debug(); |
1da177e4 | 287 | } |
7fffe31d | 288 | static const struct sysrq_key_op sysrq_showregs_op = { |
1da177e4 | 289 | .handler = sysrq_handle_showregs, |
afa80ccb | 290 | .help_msg = "show-registers(p)", |
1da177e4 LT |
291 | .action_msg = "Show Regs", |
292 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
293 | }; | |
294 | ||
1495cc9d | 295 | static void sysrq_handle_showstate(int key) |
1da177e4 LT |
296 | { |
297 | show_state(); | |
3494fc30 | 298 | show_workqueue_state(); |
1da177e4 | 299 | } |
7fffe31d | 300 | static const struct sysrq_key_op sysrq_showstate_op = { |
1da177e4 | 301 | .handler = sysrq_handle_showstate, |
afa80ccb | 302 | .help_msg = "show-task-states(t)", |
1da177e4 LT |
303 | .action_msg = "Show State", |
304 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
305 | }; | |
306 | ||
1495cc9d | 307 | static void sysrq_handle_showstate_blocked(int key) |
e59e2ae2 IM |
308 | { |
309 | show_state_filter(TASK_UNINTERRUPTIBLE); | |
310 | } | |
7fffe31d | 311 | static const struct sysrq_key_op sysrq_showstate_blocked_op = { |
e59e2ae2 | 312 | .handler = sysrq_handle_showstate_blocked, |
afa80ccb | 313 | .help_msg = "show-blocked-tasks(w)", |
e59e2ae2 IM |
314 | .action_msg = "Show Blocked State", |
315 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
316 | }; | |
317 | ||
69f698ad PZ |
318 | #ifdef CONFIG_TRACING |
319 | #include <linux/ftrace.h> | |
320 | ||
1495cc9d | 321 | static void sysrq_ftrace_dump(int key) |
69f698ad | 322 | { |
cecbca96 | 323 | ftrace_dump(DUMP_ALL); |
69f698ad | 324 | } |
7fffe31d | 325 | static const struct sysrq_key_op sysrq_ftrace_dump_op = { |
69f698ad | 326 | .handler = sysrq_ftrace_dump, |
afa80ccb | 327 | .help_msg = "dump-ftrace-buffer(z)", |
69f698ad PZ |
328 | .action_msg = "Dump ftrace buffer", |
329 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
330 | }; | |
331 | #else | |
7fffe31d | 332 | #define sysrq_ftrace_dump_op (*(const struct sysrq_key_op *)NULL) |
69f698ad | 333 | #endif |
e59e2ae2 | 334 | |
1495cc9d | 335 | static void sysrq_handle_showmem(int key) |
1da177e4 | 336 | { |
9af744d7 | 337 | show_mem(0, NULL); |
1da177e4 | 338 | } |
7fffe31d | 339 | static const struct sysrq_key_op sysrq_showmem_op = { |
1da177e4 | 340 | .handler = sysrq_handle_showmem, |
afa80ccb | 341 | .help_msg = "show-memory-usage(m)", |
1da177e4 LT |
342 | .action_msg = "Show Memory", |
343 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
344 | }; | |
345 | ||
bf36b901 AM |
346 | /* |
347 | * Signal sysrq helper function. Sends a signal to all user processes. | |
348 | */ | |
1da177e4 LT |
349 | static void send_sig_all(int sig) |
350 | { | |
351 | struct task_struct *p; | |
352 | ||
e502babe | 353 | read_lock(&tasklist_lock); |
1da177e4 | 354 | for_each_process(p) { |
d3a532a9 AV |
355 | if (p->flags & PF_KTHREAD) |
356 | continue; | |
357 | if (is_global_init(p)) | |
358 | continue; | |
359 | ||
b16503ba | 360 | do_send_sig_info(sig, SEND_SIG_PRIV, p, PIDTYPE_MAX); |
1da177e4 | 361 | } |
e502babe | 362 | read_unlock(&tasklist_lock); |
1da177e4 LT |
363 | } |
364 | ||
1495cc9d | 365 | static void sysrq_handle_term(int key) |
1da177e4 LT |
366 | { |
367 | send_sig_all(SIGTERM); | |
a8fe19eb | 368 | console_loglevel = CONSOLE_LOGLEVEL_DEBUG; |
1da177e4 | 369 | } |
7fffe31d | 370 | static const struct sysrq_key_op sysrq_term_op = { |
1da177e4 | 371 | .handler = sysrq_handle_term, |
afa80ccb | 372 | .help_msg = "terminate-all-tasks(e)", |
1da177e4 LT |
373 | .action_msg = "Terminate All Tasks", |
374 | .enable_mask = SYSRQ_ENABLE_SIGNAL, | |
375 | }; | |
376 | ||
65f27f38 | 377 | static void moom_callback(struct work_struct *ignored) |
1da177e4 | 378 | { |
6e0fc46d DR |
379 | const gfp_t gfp_mask = GFP_KERNEL; |
380 | struct oom_control oc = { | |
381 | .zonelist = node_zonelist(first_memory_node, gfp_mask), | |
382 | .nodemask = NULL, | |
2a966b77 | 383 | .memcg = NULL, |
6e0fc46d | 384 | .gfp_mask = gfp_mask, |
54e9e291 | 385 | .order = -1, |
6e0fc46d DR |
386 | }; |
387 | ||
dc56401f | 388 | mutex_lock(&oom_lock); |
6e0fc46d | 389 | if (!out_of_memory(&oc)) |
d75da004 | 390 | pr_info("OOM request ignored. No task eligible\n"); |
dc56401f | 391 | mutex_unlock(&oom_lock); |
1da177e4 LT |
392 | } |
393 | ||
65f27f38 | 394 | static DECLARE_WORK(moom_work, moom_callback); |
1da177e4 | 395 | |
1495cc9d | 396 | static void sysrq_handle_moom(int key) |
1da177e4 LT |
397 | { |
398 | schedule_work(&moom_work); | |
399 | } | |
7fffe31d | 400 | static const struct sysrq_key_op sysrq_moom_op = { |
1da177e4 | 401 | .handler = sysrq_handle_moom, |
afa80ccb | 402 | .help_msg = "memory-full-oom-kill(f)", |
1da177e4 | 403 | .action_msg = "Manual OOM execution", |
b4236f81 | 404 | .enable_mask = SYSRQ_ENABLE_SIGNAL, |
1da177e4 LT |
405 | }; |
406 | ||
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 | }; | |
c2d75438 | 417 | |
1495cc9d | 418 | static void sysrq_handle_kill(int key) |
1da177e4 LT |
419 | { |
420 | send_sig_all(SIGKILL); | |
a8fe19eb | 421 | console_loglevel = CONSOLE_LOGLEVEL_DEBUG; |
1da177e4 | 422 | } |
7fffe31d | 423 | static const struct sysrq_key_op sysrq_kill_op = { |
1da177e4 | 424 | .handler = sysrq_handle_kill, |
afa80ccb | 425 | .help_msg = "kill-all-tasks(i)", |
1da177e4 LT |
426 | .action_msg = "Kill All Tasks", |
427 | .enable_mask = SYSRQ_ENABLE_SIGNAL, | |
428 | }; | |
429 | ||
1495cc9d | 430 | static void sysrq_handle_unrt(int key) |
1da177e4 LT |
431 | { |
432 | normalize_rt_tasks(); | |
433 | } | |
7fffe31d | 434 | static const struct sysrq_key_op sysrq_unrt_op = { |
1da177e4 | 435 | .handler = sysrq_handle_unrt, |
afa80ccb | 436 | .help_msg = "nice-all-RT-tasks(n)", |
1da177e4 LT |
437 | .action_msg = "Nice All RT Tasks", |
438 | .enable_mask = SYSRQ_ENABLE_RTNICE, | |
439 | }; | |
440 | ||
441 | /* Key Operations table and lock */ | |
442 | static DEFINE_SPINLOCK(sysrq_key_table_lock); | |
bf36b901 | 443 | |
a27eb0cb | 444 | static const struct sysrq_key_op *sysrq_key_table[62] = { |
bf36b901 AM |
445 | &sysrq_loglevel_op, /* 0 */ |
446 | &sysrq_loglevel_op, /* 1 */ | |
447 | &sysrq_loglevel_op, /* 2 */ | |
448 | &sysrq_loglevel_op, /* 3 */ | |
449 | &sysrq_loglevel_op, /* 4 */ | |
450 | &sysrq_loglevel_op, /* 5 */ | |
451 | &sysrq_loglevel_op, /* 6 */ | |
452 | &sysrq_loglevel_op, /* 7 */ | |
453 | &sysrq_loglevel_op, /* 8 */ | |
454 | &sysrq_loglevel_op, /* 9 */ | |
455 | ||
456 | /* | |
d346cce3 RD |
457 | * a: Don't use for system provided sysrqs, it is handled specially on |
458 | * sparc and will never arrive. | |
bf36b901 AM |
459 | */ |
460 | NULL, /* a */ | |
461 | &sysrq_reboot_op, /* b */ | |
5e351410 | 462 | &sysrq_crash_op, /* c */ |
bf36b901 AM |
463 | &sysrq_showlocks_op, /* d */ |
464 | &sysrq_term_op, /* e */ | |
465 | &sysrq_moom_op, /* f */ | |
364b5b7b | 466 | /* g: May be registered for the kernel debugger */ |
bf36b901 | 467 | NULL, /* g */ |
c2d75438 | 468 | NULL, /* h - reserved for help */ |
bf36b901 | 469 | &sysrq_kill_op, /* i */ |
c2d75438 ES |
470 | #ifdef CONFIG_BLOCK |
471 | &sysrq_thaw_op, /* j */ | |
472 | #else | |
bf36b901 | 473 | NULL, /* j */ |
c2d75438 | 474 | #endif |
bf36b901 | 475 | &sysrq_SAK_op, /* k */ |
5045bcae RR |
476 | #ifdef CONFIG_SMP |
477 | &sysrq_showallcpus_op, /* l */ | |
478 | #else | |
bf36b901 | 479 | NULL, /* l */ |
5045bcae | 480 | #endif |
bf36b901 AM |
481 | &sysrq_showmem_op, /* m */ |
482 | &sysrq_unrt_op, /* n */ | |
d346cce3 | 483 | /* o: This will often be registered as 'Off' at init time */ |
bf36b901 AM |
484 | NULL, /* o */ |
485 | &sysrq_showregs_op, /* p */ | |
88ad0bf6 | 486 | &sysrq_show_timers_op, /* q */ |
d346cce3 | 487 | &sysrq_unraw_op, /* r */ |
bf36b901 AM |
488 | &sysrq_sync_op, /* s */ |
489 | &sysrq_showstate_op, /* t */ | |
490 | &sysrq_mountro_op, /* u */ | |
364b5b7b | 491 | /* v: May be registered for frame buffer console restore */ |
bf36b901 | 492 | NULL, /* v */ |
d346cce3 | 493 | &sysrq_showstate_blocked_op, /* w */ |
d1e9a4f5 | 494 | /* x: May be registered on mips for TLB dump */ |
d346cce3 | 495 | /* x: May be registered on ppc/powerpc for xmon */ |
916ca14a | 496 | /* x: May be registered on sparc64 for global PMU dump */ |
d346cce3 | 497 | NULL, /* x */ |
93dae5b7 | 498 | /* y: May be registered on sparc64 for global register dump */ |
bf36b901 | 499 | NULL, /* y */ |
69f698ad | 500 | &sysrq_ftrace_dump_op, /* z */ |
a27eb0cb AP |
501 | NULL, /* A */ |
502 | NULL, /* B */ | |
503 | NULL, /* C */ | |
504 | NULL, /* D */ | |
505 | NULL, /* E */ | |
506 | NULL, /* F */ | |
507 | NULL, /* G */ | |
508 | NULL, /* H */ | |
509 | NULL, /* I */ | |
510 | NULL, /* J */ | |
511 | NULL, /* K */ | |
512 | NULL, /* L */ | |
513 | NULL, /* M */ | |
514 | NULL, /* N */ | |
515 | NULL, /* O */ | |
516 | NULL, /* P */ | |
517 | NULL, /* Q */ | |
518 | NULL, /* R */ | |
519 | NULL, /* S */ | |
520 | NULL, /* T */ | |
521 | NULL, /* U */ | |
522 | NULL, /* V */ | |
523 | NULL, /* W */ | |
524 | NULL, /* X */ | |
525 | NULL, /* Y */ | |
526 | NULL, /* Z */ | |
1da177e4 LT |
527 | }; |
528 | ||
529 | /* key2index calculation, -1 on invalid index */ | |
bf36b901 AM |
530 | static int sysrq_key_table_key2index(int key) |
531 | { | |
1da177e4 | 532 | int retval; |
bf36b901 AM |
533 | |
534 | if ((key >= '0') && (key <= '9')) | |
1da177e4 | 535 | retval = key - '0'; |
bf36b901 | 536 | else if ((key >= 'a') && (key <= 'z')) |
1da177e4 | 537 | retval = key + 10 - 'a'; |
a27eb0cb AP |
538 | else if ((key >= 'A') && (key <= 'Z')) |
539 | retval = key + 36 - 'A'; | |
bf36b901 | 540 | else |
1da177e4 | 541 | retval = -1; |
1da177e4 LT |
542 | return retval; |
543 | } | |
544 | ||
545 | /* | |
546 | * get and put functions for the table, exposed to modules. | |
547 | */ | |
23cbedf8 | 548 | static const struct sysrq_key_op *__sysrq_get_key_op(int key) |
bf36b901 | 549 | { |
23cbedf8 | 550 | const struct sysrq_key_op *op_p = NULL; |
1da177e4 | 551 | int i; |
bf36b901 | 552 | |
1da177e4 | 553 | i = sysrq_key_table_key2index(key); |
bf36b901 AM |
554 | if (i != -1) |
555 | op_p = sysrq_key_table[i]; | |
97f5f0cd | 556 | |
1da177e4 LT |
557 | return op_p; |
558 | } | |
559 | ||
23cbedf8 | 560 | static void __sysrq_put_key_op(int key, const struct sysrq_key_op *op_p) |
bf36b901 AM |
561 | { |
562 | int i = sysrq_key_table_key2index(key); | |
1da177e4 | 563 | |
1da177e4 LT |
564 | if (i != -1) |
565 | sysrq_key_table[i] = op_p; | |
566 | } | |
567 | ||
f335397d | 568 | void __handle_sysrq(int key, bool check_mask) |
1da177e4 | 569 | { |
23cbedf8 | 570 | const struct sysrq_key_op *op_p; |
1da177e4 | 571 | int orig_log_level; |
c39ea0b9 | 572 | int orig_suppress_printk; |
bf36b901 | 573 | int i; |
1da177e4 | 574 | |
c39ea0b9 FT |
575 | orig_suppress_printk = suppress_printk; |
576 | suppress_printk = 0; | |
577 | ||
722773af | 578 | rcu_sysrq_start(); |
984d74a7 | 579 | rcu_read_lock(); |
fb144adc AW |
580 | /* |
581 | * Raise the apparent loglevel to maximum so that the sysrq header | |
582 | * is shown to provide the user with positive feedback. We do not | |
583 | * simply emit this at KERN_EMERG as that would change message | |
584 | * routing in the consumers of /proc/kmsg. | |
585 | */ | |
1da177e4 | 586 | orig_log_level = console_loglevel; |
a8fe19eb | 587 | console_loglevel = CONSOLE_LOGLEVEL_DEFAULT; |
1da177e4 LT |
588 | |
589 | op_p = __sysrq_get_key_op(key); | |
590 | if (op_p) { | |
bf36b901 AM |
591 | /* |
592 | * Should we check for enabled operations (/proc/sysrq-trigger | |
593 | * should not) and is the invoked operation enabled? | |
594 | */ | |
5d6f647f | 595 | if (!check_mask || sysrq_on_mask(op_p->enable_mask)) { |
c3fee609 | 596 | pr_info("%s\n", op_p->action_msg); |
1da177e4 | 597 | console_loglevel = orig_log_level; |
1495cc9d | 598 | op_p->handler(key); |
bf36b901 | 599 | } else { |
c3fee609 | 600 | pr_info("This sysrq operation is disabled.\n"); |
075e1a0c | 601 | console_loglevel = orig_log_level; |
bf36b901 | 602 | } |
1da177e4 | 603 | } else { |
c3fee609 | 604 | pr_info("HELP : "); |
1da177e4 | 605 | /* Only print the help msg once per handler */ |
bf36b901 AM |
606 | for (i = 0; i < ARRAY_SIZE(sysrq_key_table); i++) { |
607 | if (sysrq_key_table[i]) { | |
608 | int j; | |
609 | ||
610 | for (j = 0; sysrq_key_table[i] != | |
611 | sysrq_key_table[j]; j++) | |
612 | ; | |
613 | if (j != i) | |
614 | continue; | |
401e4a7c | 615 | pr_cont("%s ", sysrq_key_table[i]->help_msg); |
bf36b901 | 616 | } |
1da177e4 | 617 | } |
401e4a7c | 618 | pr_cont("\n"); |
1da177e4 LT |
619 | console_loglevel = orig_log_level; |
620 | } | |
984d74a7 | 621 | rcu_read_unlock(); |
722773af | 622 | rcu_sysrq_end(); |
c39ea0b9 FT |
623 | |
624 | suppress_printk = orig_suppress_printk; | |
1da177e4 LT |
625 | } |
626 | ||
f335397d | 627 | void handle_sysrq(int key) |
1da177e4 | 628 | { |
5d6f647f | 629 | if (sysrq_on()) |
f335397d | 630 | __handle_sysrq(key, true); |
1da177e4 | 631 | } |
bf36b901 | 632 | EXPORT_SYMBOL(handle_sysrq); |
1da177e4 | 633 | |
97f5f0cd | 634 | #ifdef CONFIG_INPUT |
ffb6e0c9 | 635 | static int sysrq_reset_downtime_ms; |
97f5f0cd DT |
636 | |
637 | /* Simple translation table for the SysRq keys */ | |
fcb71930 | 638 | static const unsigned char sysrq_xlate[KEY_CNT] = |
97f5f0cd DT |
639 | "\000\0331234567890-=\177\t" /* 0x00 - 0x0f */ |
640 | "qwertyuiop[]\r\000as" /* 0x10 - 0x1f */ | |
641 | "dfghjkl;'`\000\\zxcv" /* 0x20 - 0x2f */ | |
642 | "bnm,./\000*\000 \000\201\202\203\204\205" /* 0x30 - 0x3f */ | |
643 | "\206\207\210\211\212\000\000789-456+1" /* 0x40 - 0x4f */ | |
644 | "230\177\000\000\213\214\000\000\000\000\000\000\000\000\000\000" /* 0x50 - 0x5f */ | |
645 | "\r\000/"; /* 0x60 - 0x6f */ | |
646 | ||
fcb71930 DT |
647 | struct sysrq_state { |
648 | struct input_handle handle; | |
649 | struct work_struct reinject_work; | |
650 | unsigned long key_down[BITS_TO_LONGS(KEY_CNT)]; | |
651 | unsigned int alt; | |
652 | unsigned int alt_use; | |
a27eb0cb AP |
653 | unsigned int shift; |
654 | unsigned int shift_use; | |
fcb71930 DT |
655 | bool active; |
656 | bool need_reinject; | |
7ab7b5ad | 657 | bool reinjecting; |
154b7a48 MP |
658 | |
659 | /* reset sequence handling */ | |
660 | bool reset_canceled; | |
3d289517 | 661 | bool reset_requested; |
154b7a48 MP |
662 | unsigned long reset_keybit[BITS_TO_LONGS(KEY_CNT)]; |
663 | int reset_seq_len; | |
664 | int reset_seq_cnt; | |
665 | int reset_seq_version; | |
39030786 | 666 | struct timer_list keyreset_timer; |
fcb71930 DT |
667 | }; |
668 | ||
154b7a48 MP |
669 | #define SYSRQ_KEY_RESET_MAX 20 /* Should be plenty */ |
670 | static unsigned short sysrq_reset_seq[SYSRQ_KEY_RESET_MAX]; | |
671 | static unsigned int sysrq_reset_seq_len; | |
672 | static unsigned int sysrq_reset_seq_version = 1; | |
673 | ||
674 | static void sysrq_parse_reset_sequence(struct sysrq_state *state) | |
675 | { | |
676 | int i; | |
677 | unsigned short key; | |
678 | ||
679 | state->reset_seq_cnt = 0; | |
680 | ||
681 | for (i = 0; i < sysrq_reset_seq_len; i++) { | |
682 | key = sysrq_reset_seq[i]; | |
683 | ||
684 | if (key == KEY_RESERVED || key > KEY_MAX) | |
685 | break; | |
686 | ||
687 | __set_bit(key, state->reset_keybit); | |
688 | state->reset_seq_len++; | |
689 | ||
690 | if (test_bit(key, state->key_down)) | |
691 | state->reset_seq_cnt++; | |
692 | } | |
693 | ||
694 | /* Disable reset until old keys are not released */ | |
695 | state->reset_canceled = state->reset_seq_cnt != 0; | |
696 | ||
697 | state->reset_seq_version = sysrq_reset_seq_version; | |
698 | } | |
699 | ||
8c318fa9 | 700 | static void sysrq_do_reset(struct timer_list *t) |
39030786 | 701 | { |
8c318fa9 | 702 | struct sysrq_state *state = from_timer(state, t, keyreset_timer); |
3d289517 MP |
703 | |
704 | state->reset_requested = true; | |
705 | ||
8fefbc6d | 706 | orderly_reboot(); |
39030786 MP |
707 | } |
708 | ||
709 | static void sysrq_handle_reset_request(struct sysrq_state *state) | |
710 | { | |
3d289517 MP |
711 | if (state->reset_requested) |
712 | __handle_sysrq(sysrq_xlate[KEY_B], false); | |
713 | ||
39030786 MP |
714 | if (sysrq_reset_downtime_ms) |
715 | mod_timer(&state->keyreset_timer, | |
716 | jiffies + msecs_to_jiffies(sysrq_reset_downtime_ms)); | |
717 | else | |
8c318fa9 | 718 | sysrq_do_reset(&state->keyreset_timer); |
39030786 MP |
719 | } |
720 | ||
721 | static void sysrq_detect_reset_sequence(struct sysrq_state *state, | |
154b7a48 MP |
722 | unsigned int code, int value) |
723 | { | |
724 | if (!test_bit(code, state->reset_keybit)) { | |
725 | /* | |
726 | * Pressing any key _not_ in reset sequence cancels | |
39030786 MP |
727 | * the reset sequence. Also cancelling the timer in |
728 | * case additional keys were pressed after a reset | |
729 | * has been requested. | |
154b7a48 | 730 | */ |
39030786 | 731 | if (value && state->reset_seq_cnt) { |
154b7a48 | 732 | state->reset_canceled = true; |
39030786 MP |
733 | del_timer(&state->keyreset_timer); |
734 | } | |
154b7a48 | 735 | } else if (value == 0) { |
39030786 MP |
736 | /* |
737 | * Key release - all keys in the reset sequence need | |
738 | * to be pressed and held for the reset timeout | |
739 | * to hold. | |
740 | */ | |
741 | del_timer(&state->keyreset_timer); | |
742 | ||
154b7a48 MP |
743 | if (--state->reset_seq_cnt == 0) |
744 | state->reset_canceled = false; | |
745 | } else if (value == 1) { | |
746 | /* key press, not autorepeat */ | |
747 | if (++state->reset_seq_cnt == state->reset_seq_len && | |
748 | !state->reset_canceled) { | |
39030786 | 749 | sysrq_handle_reset_request(state); |
154b7a48 MP |
750 | } |
751 | } | |
154b7a48 MP |
752 | } |
753 | ||
4c076eb0 MP |
754 | #ifdef CONFIG_OF |
755 | static void sysrq_of_get_keyreset_config(void) | |
756 | { | |
757 | u32 key; | |
758 | struct device_node *np; | |
759 | struct property *prop; | |
760 | const __be32 *p; | |
761 | ||
762 | np = of_find_node_by_path("/chosen/linux,sysrq-reset-seq"); | |
763 | if (!np) { | |
764 | pr_debug("No sysrq node found"); | |
765 | return; | |
766 | } | |
767 | ||
768 | /* Reset in case a __weak definition was present */ | |
769 | sysrq_reset_seq_len = 0; | |
770 | ||
771 | of_property_for_each_u32(np, "keyset", prop, p, key) { | |
772 | if (key == KEY_RESERVED || key > KEY_MAX || | |
773 | sysrq_reset_seq_len == SYSRQ_KEY_RESET_MAX) | |
774 | break; | |
775 | ||
776 | sysrq_reset_seq[sysrq_reset_seq_len++] = (unsigned short)key; | |
777 | } | |
778 | ||
779 | /* Get reset timeout if any. */ | |
780 | of_property_read_u32(np, "timeout-ms", &sysrq_reset_downtime_ms); | |
279070b9 YL |
781 | |
782 | of_node_put(np); | |
4c076eb0 MP |
783 | } |
784 | #else | |
785 | static void sysrq_of_get_keyreset_config(void) | |
786 | { | |
787 | } | |
788 | #endif | |
789 | ||
fcb71930 DT |
790 | static void sysrq_reinject_alt_sysrq(struct work_struct *work) |
791 | { | |
792 | struct sysrq_state *sysrq = | |
793 | container_of(work, struct sysrq_state, reinject_work); | |
794 | struct input_handle *handle = &sysrq->handle; | |
795 | unsigned int alt_code = sysrq->alt_use; | |
796 | ||
797 | if (sysrq->need_reinject) { | |
7ab7b5ad DT |
798 | /* we do not want the assignment to be reordered */ |
799 | sysrq->reinjecting = true; | |
800 | mb(); | |
801 | ||
fcb71930 DT |
802 | /* Simulate press and release of Alt + SysRq */ |
803 | input_inject_event(handle, EV_KEY, alt_code, 1); | |
804 | input_inject_event(handle, EV_KEY, KEY_SYSRQ, 1); | |
805 | input_inject_event(handle, EV_SYN, SYN_REPORT, 1); | |
806 | ||
807 | input_inject_event(handle, EV_KEY, KEY_SYSRQ, 0); | |
808 | input_inject_event(handle, EV_KEY, alt_code, 0); | |
809 | input_inject_event(handle, EV_SYN, SYN_REPORT, 1); | |
7ab7b5ad DT |
810 | |
811 | mb(); | |
812 | sysrq->reinjecting = false; | |
fcb71930 DT |
813 | } |
814 | } | |
97f5f0cd | 815 | |
154b7a48 MP |
816 | static bool sysrq_handle_keypress(struct sysrq_state *sysrq, |
817 | unsigned int code, int value) | |
97f5f0cd | 818 | { |
fcb71930 | 819 | bool was_active = sysrq->active; |
1966cb22 DT |
820 | bool suppress; |
821 | ||
154b7a48 | 822 | switch (code) { |
7ab7b5ad | 823 | |
154b7a48 MP |
824 | case KEY_LEFTALT: |
825 | case KEY_RIGHTALT: | |
826 | if (!value) { | |
827 | /* One of ALTs is being released */ | |
828 | if (sysrq->active && code == sysrq->alt_use) | |
829 | sysrq->active = false; | |
1966cb22 | 830 | |
154b7a48 MP |
831 | sysrq->alt = KEY_RESERVED; |
832 | ||
833 | } else if (value != 2) { | |
834 | sysrq->alt = code; | |
835 | sysrq->need_reinject = false; | |
836 | } | |
fcb71930 | 837 | break; |
97f5f0cd | 838 | |
a27eb0cb AP |
839 | case KEY_LEFTSHIFT: |
840 | case KEY_RIGHTSHIFT: | |
841 | if (!value) | |
842 | sysrq->shift = KEY_RESERVED; | |
843 | else if (value != 2) | |
844 | sysrq->shift = code; | |
845 | break; | |
846 | ||
154b7a48 MP |
847 | case KEY_SYSRQ: |
848 | if (value == 1 && sysrq->alt != KEY_RESERVED) { | |
849 | sysrq->active = true; | |
850 | sysrq->alt_use = sysrq->alt; | |
a27eb0cb AP |
851 | /* either RESERVED (for released) or actual code */ |
852 | sysrq->shift_use = sysrq->shift; | |
154b7a48 MP |
853 | /* |
854 | * If nothing else will be pressed we'll need | |
855 | * to re-inject Alt-SysRq keysroke. | |
856 | */ | |
857 | sysrq->need_reinject = true; | |
858 | } | |
97f5f0cd | 859 | |
154b7a48 MP |
860 | /* |
861 | * Pretend that sysrq was never pressed at all. This | |
862 | * is needed to properly handle KGDB which will try | |
863 | * to release all keys after exiting debugger. If we | |
864 | * do not clear key bit it KGDB will end up sending | |
865 | * release events for Alt and SysRq, potentially | |
866 | * triggering print screen function. | |
867 | */ | |
868 | if (sysrq->active) | |
869 | clear_bit(KEY_SYSRQ, sysrq->handle.dev->key); | |
f5dec511 | 870 | |
154b7a48 | 871 | break; |
fcb71930 | 872 | |
154b7a48 MP |
873 | default: |
874 | if (sysrq->active && value && value != 2) { | |
a27eb0cb AP |
875 | unsigned char c = sysrq_xlate[code]; |
876 | ||
154b7a48 | 877 | sysrq->need_reinject = false; |
a27eb0cb AP |
878 | if (sysrq->shift_use != KEY_RESERVED) |
879 | c = toupper(c); | |
880 | __handle_sysrq(c, true); | |
154b7a48 MP |
881 | } |
882 | break; | |
883 | } | |
fcb71930 | 884 | |
154b7a48 | 885 | suppress = sysrq->active; |
fcb71930 | 886 | |
154b7a48 | 887 | if (!sysrq->active) { |
fcb71930 | 888 | |
154b7a48 MP |
889 | /* |
890 | * See if reset sequence has changed since the last time. | |
891 | */ | |
892 | if (sysrq->reset_seq_version != sysrq_reset_seq_version) | |
893 | sysrq_parse_reset_sequence(sysrq); | |
fcb71930 | 894 | |
154b7a48 MP |
895 | /* |
896 | * If we are not suppressing key presses keep track of | |
897 | * keyboard state so we can release keys that have been | |
898 | * pressed before entering SysRq mode. | |
899 | */ | |
900 | if (value) | |
901 | set_bit(code, sysrq->key_down); | |
902 | else | |
903 | clear_bit(code, sysrq->key_down); | |
904 | ||
905 | if (was_active) | |
906 | schedule_work(&sysrq->reinject_work); | |
907 | ||
39030786 MP |
908 | /* Check for reset sequence */ |
909 | sysrq_detect_reset_sequence(sysrq, code, value); | |
97f5f0cd | 910 | |
154b7a48 MP |
911 | } else if (value == 0 && test_and_clear_bit(code, sysrq->key_down)) { |
912 | /* | |
913 | * Pass on release events for keys that was pressed before | |
914 | * entering SysRq mode. | |
915 | */ | |
916 | suppress = false; | |
917 | } | |
fcb71930 | 918 | |
154b7a48 MP |
919 | return suppress; |
920 | } | |
fcb71930 | 921 | |
154b7a48 MP |
922 | static bool sysrq_filter(struct input_handle *handle, |
923 | unsigned int type, unsigned int code, int value) | |
924 | { | |
925 | struct sysrq_state *sysrq = handle->private; | |
926 | bool suppress; | |
fcb71930 | 927 | |
154b7a48 MP |
928 | /* |
929 | * Do not filter anything if we are in the process of re-injecting | |
930 | * Alt+SysRq combination. | |
931 | */ | |
932 | if (sysrq->reinjecting) | |
933 | return false; | |
934 | ||
935 | switch (type) { | |
936 | ||
937 | case EV_SYN: | |
938 | suppress = false; | |
939 | break; | |
940 | ||
941 | case EV_KEY: | |
942 | suppress = sysrq_handle_keypress(sysrq, code, value); | |
97f5f0cd DT |
943 | break; |
944 | ||
945 | default: | |
fcb71930 | 946 | suppress = sysrq->active; |
97f5f0cd DT |
947 | break; |
948 | } | |
949 | ||
1966cb22 | 950 | return suppress; |
97f5f0cd DT |
951 | } |
952 | ||
953 | static int sysrq_connect(struct input_handler *handler, | |
954 | struct input_dev *dev, | |
955 | const struct input_device_id *id) | |
956 | { | |
fcb71930 | 957 | struct sysrq_state *sysrq; |
97f5f0cd DT |
958 | int error; |
959 | ||
fcb71930 DT |
960 | sysrq = kzalloc(sizeof(struct sysrq_state), GFP_KERNEL); |
961 | if (!sysrq) | |
97f5f0cd DT |
962 | return -ENOMEM; |
963 | ||
fcb71930 DT |
964 | INIT_WORK(&sysrq->reinject_work, sysrq_reinject_alt_sysrq); |
965 | ||
966 | sysrq->handle.dev = dev; | |
967 | sysrq->handle.handler = handler; | |
968 | sysrq->handle.name = "sysrq"; | |
969 | sysrq->handle.private = sysrq; | |
8c318fa9 | 970 | timer_setup(&sysrq->keyreset_timer, sysrq_do_reset, 0); |
97f5f0cd | 971 | |
fcb71930 | 972 | error = input_register_handle(&sysrq->handle); |
97f5f0cd DT |
973 | if (error) { |
974 | pr_err("Failed to register input sysrq handler, error %d\n", | |
975 | error); | |
976 | goto err_free; | |
977 | } | |
978 | ||
fcb71930 | 979 | error = input_open_device(&sysrq->handle); |
97f5f0cd DT |
980 | if (error) { |
981 | pr_err("Failed to open input device, error %d\n", error); | |
982 | goto err_unregister; | |
983 | } | |
984 | ||
985 | return 0; | |
986 | ||
987 | err_unregister: | |
fcb71930 | 988 | input_unregister_handle(&sysrq->handle); |
97f5f0cd | 989 | err_free: |
fcb71930 | 990 | kfree(sysrq); |
97f5f0cd DT |
991 | return error; |
992 | } | |
993 | ||
994 | static void sysrq_disconnect(struct input_handle *handle) | |
995 | { | |
fcb71930 DT |
996 | struct sysrq_state *sysrq = handle->private; |
997 | ||
97f5f0cd | 998 | input_close_device(handle); |
fcb71930 | 999 | cancel_work_sync(&sysrq->reinject_work); |
39030786 | 1000 | del_timer_sync(&sysrq->keyreset_timer); |
97f5f0cd | 1001 | input_unregister_handle(handle); |
fcb71930 | 1002 | kfree(sysrq); |
97f5f0cd DT |
1003 | } |
1004 | ||
1005 | /* | |
1966cb22 DT |
1006 | * We are matching on KEY_LEFTALT instead of KEY_SYSRQ because not all |
1007 | * keyboards have SysRq key predefined and so user may add it to keymap | |
97f5f0cd DT |
1008 | * later, but we expect all such keyboards to have left alt. |
1009 | */ | |
1010 | static const struct input_device_id sysrq_ids[] = { | |
1011 | { | |
1012 | .flags = INPUT_DEVICE_ID_MATCH_EVBIT | | |
1013 | INPUT_DEVICE_ID_MATCH_KEYBIT, | |
802c0388 AM |
1014 | .evbit = { [BIT_WORD(EV_KEY)] = BIT_MASK(EV_KEY) }, |
1015 | .keybit = { [BIT_WORD(KEY_LEFTALT)] = BIT_MASK(KEY_LEFTALT) }, | |
97f5f0cd DT |
1016 | }, |
1017 | { }, | |
1018 | }; | |
1019 | ||
1020 | static struct input_handler sysrq_handler = { | |
1021 | .filter = sysrq_filter, | |
1022 | .connect = sysrq_connect, | |
1023 | .disconnect = sysrq_disconnect, | |
1024 | .name = "sysrq", | |
1025 | .id_table = sysrq_ids, | |
1026 | }; | |
1027 | ||
97f5f0cd DT |
1028 | static inline void sysrq_register_handler(void) |
1029 | { | |
1030 | int error; | |
1031 | ||
4c076eb0 MP |
1032 | sysrq_of_get_keyreset_config(); |
1033 | ||
97f5f0cd DT |
1034 | error = input_register_handler(&sysrq_handler); |
1035 | if (error) | |
1036 | pr_err("Failed to register input handler, error %d", error); | |
97f5f0cd DT |
1037 | } |
1038 | ||
1039 | static inline void sysrq_unregister_handler(void) | |
1040 | { | |
f06327d1 | 1041 | input_unregister_handler(&sysrq_handler); |
97f5f0cd DT |
1042 | } |
1043 | ||
154b7a48 MP |
1044 | static int sysrq_reset_seq_param_set(const char *buffer, |
1045 | const struct kernel_param *kp) | |
1046 | { | |
1047 | unsigned long val; | |
1048 | int error; | |
1049 | ||
86b40567 | 1050 | error = kstrtoul(buffer, 0, &val); |
154b7a48 MP |
1051 | if (error < 0) |
1052 | return error; | |
1053 | ||
1054 | if (val > KEY_MAX) | |
1055 | return -EINVAL; | |
1056 | ||
1057 | *((unsigned short *)kp->arg) = val; | |
1058 | sysrq_reset_seq_version++; | |
1059 | ||
1060 | return 0; | |
1061 | } | |
1062 | ||
9c27847d | 1063 | static const struct kernel_param_ops param_ops_sysrq_reset_seq = { |
154b7a48 MP |
1064 | .get = param_get_ushort, |
1065 | .set = sysrq_reset_seq_param_set, | |
1066 | }; | |
1067 | ||
1068 | #define param_check_sysrq_reset_seq(name, p) \ | |
1069 | __param_check(name, p, unsigned short) | |
1070 | ||
3bce6f64 PG |
1071 | /* |
1072 | * not really modular, but the easiest way to keep compat with existing | |
1073 | * bootargs behaviour is to continue using module_param here. | |
1074 | */ | |
154b7a48 MP |
1075 | module_param_array_named(reset_seq, sysrq_reset_seq, sysrq_reset_seq, |
1076 | &sysrq_reset_seq_len, 0644); | |
1077 | ||
39030786 MP |
1078 | module_param_named(sysrq_downtime_ms, sysrq_reset_downtime_ms, int, 0644); |
1079 | ||
97f5f0cd DT |
1080 | #else |
1081 | ||
1082 | static inline void sysrq_register_handler(void) | |
1083 | { | |
1084 | } | |
1085 | ||
1086 | static inline void sysrq_unregister_handler(void) | |
1087 | { | |
1088 | } | |
1089 | ||
1090 | #endif /* CONFIG_INPUT */ | |
1091 | ||
1092 | int sysrq_toggle_support(int enable_mask) | |
1093 | { | |
1094 | bool was_enabled = sysrq_on(); | |
1095 | ||
1096 | sysrq_enabled = enable_mask; | |
1097 | ||
1098 | if (was_enabled != sysrq_on()) { | |
1099 | if (sysrq_on()) | |
1100 | sysrq_register_handler(); | |
1101 | else | |
1102 | sysrq_unregister_handler(); | |
1103 | } | |
1104 | ||
1105 | return 0; | |
1106 | } | |
66bb1c95 | 1107 | EXPORT_SYMBOL_GPL(sysrq_toggle_support); |
97f5f0cd | 1108 | |
23cbedf8 EV |
1109 | static int __sysrq_swap_key_ops(int key, const struct sysrq_key_op *insert_op_p, |
1110 | const struct sysrq_key_op *remove_op_p) | |
bf36b901 | 1111 | { |
1da177e4 | 1112 | int retval; |
1da177e4 | 1113 | |
984d74a7 | 1114 | spin_lock(&sysrq_key_table_lock); |
1da177e4 LT |
1115 | if (__sysrq_get_key_op(key) == remove_op_p) { |
1116 | __sysrq_put_key_op(key, insert_op_p); | |
1117 | retval = 0; | |
1118 | } else { | |
1119 | retval = -1; | |
1120 | } | |
984d74a7 RR |
1121 | spin_unlock(&sysrq_key_table_lock); |
1122 | ||
1123 | /* | |
1124 | * A concurrent __handle_sysrq either got the old op or the new op. | |
1125 | * Wait for it to go away before returning, so the code for an old | |
1126 | * op is not freed (eg. on module unload) while it is in use. | |
1127 | */ | |
1128 | synchronize_rcu(); | |
1129 | ||
1da177e4 LT |
1130 | return retval; |
1131 | } | |
1132 | ||
23cbedf8 | 1133 | int register_sysrq_key(int key, const struct sysrq_key_op *op_p) |
1da177e4 LT |
1134 | { |
1135 | return __sysrq_swap_key_ops(key, op_p, NULL); | |
1136 | } | |
bf36b901 | 1137 | EXPORT_SYMBOL(register_sysrq_key); |
1da177e4 | 1138 | |
23cbedf8 | 1139 | int unregister_sysrq_key(int key, const struct sysrq_key_op *op_p) |
1da177e4 LT |
1140 | { |
1141 | return __sysrq_swap_key_ops(key, NULL, op_p); | |
1142 | } | |
1da177e4 | 1143 | EXPORT_SYMBOL(unregister_sysrq_key); |
f40cbaa5 AD |
1144 | |
1145 | #ifdef CONFIG_PROC_FS | |
1146 | /* | |
1147 | * writing 'C' to /proc/sysrq-trigger is like sysrq-C | |
1148 | */ | |
1149 | static ssize_t write_sysrq_trigger(struct file *file, const char __user *buf, | |
1150 | size_t count, loff_t *ppos) | |
1151 | { | |
1152 | if (count) { | |
1153 | char c; | |
1154 | ||
1155 | if (get_user(c, buf)) | |
1156 | return -EFAULT; | |
f335397d | 1157 | __handle_sysrq(c, false); |
f40cbaa5 | 1158 | } |
97f5f0cd | 1159 | |
f40cbaa5 AD |
1160 | return count; |
1161 | } | |
1162 | ||
97a32539 AD |
1163 | static const struct proc_ops sysrq_trigger_proc_ops = { |
1164 | .proc_write = write_sysrq_trigger, | |
1165 | .proc_lseek = noop_llseek, | |
f40cbaa5 AD |
1166 | }; |
1167 | ||
97f5f0cd DT |
1168 | static void sysrq_init_procfs(void) |
1169 | { | |
1170 | if (!proc_create("sysrq-trigger", S_IWUSR, NULL, | |
97a32539 | 1171 | &sysrq_trigger_proc_ops)) |
97f5f0cd DT |
1172 | pr_err("Failed to register proc interface\n"); |
1173 | } | |
1174 | ||
1175 | #else | |
1176 | ||
1177 | static inline void sysrq_init_procfs(void) | |
1178 | { | |
1179 | } | |
1180 | ||
1181 | #endif /* CONFIG_PROC_FS */ | |
1182 | ||
f40cbaa5 AD |
1183 | static int __init sysrq_init(void) |
1184 | { | |
97f5f0cd DT |
1185 | sysrq_init_procfs(); |
1186 | ||
1187 | if (sysrq_on()) | |
1188 | sysrq_register_handler(); | |
1189 | ||
f40cbaa5 AD |
1190 | return 0; |
1191 | } | |
3bce6f64 | 1192 | device_initcall(sysrq_init); |