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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 | |
bcb48185 | 101 | static void sysrq_handle_loglevel(u8 key) |
1da177e4 | 102 | { |
00ef7eff | 103 | u8 loglevel = key - '0'; |
97f5f0cd | 104 | |
a8fe19eb | 105 | console_loglevel = CONSOLE_LOGLEVEL_DEFAULT; |
00ef7eff JS |
106 | pr_info("Loglevel set to %u\n", loglevel); |
107 | console_loglevel = loglevel; | |
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 |
bcb48185 | 117 | static void sysrq_handle_SAK(u8 key) |
1da177e4 | 118 | { |
8b6312f4 | 119 | struct work_struct *SAK_work = &vc_cons[fg_console].SAK_work; |
2c4a4cde | 120 | |
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 | |
bcb48185 | 134 | static void sysrq_handle_unraw(u8 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 | ||
bcb48185 | 149 | static void sysrq_handle_crash(u8 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 | |
bcb48185 | 163 | static void sysrq_handle_reboot(u8 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 | |
bcb48185 | 178 | static void sysrq_handle_sync(u8 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 | ||
bcb48185 | 189 | static void sysrq_handle_show_timers(u8 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 | ||
bcb48185 | 200 | static void sysrq_handle_mountro(u8 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 |
bcb48185 | 212 | static void sysrq_handle_showlocks(u8 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. */ | |
5390e7f4 CD |
234 | if (idle_cpu(smp_processor_id())) { |
235 | pr_info("CPU%d: backtrace skipped as idling\n", smp_processor_id()); | |
5045bcae | 236 | return; |
5390e7f4 | 237 | } |
5045bcae | 238 | |
6ac972dd | 239 | raw_spin_lock_irqsave(&show_lock, flags); |
401e4a7c | 240 | pr_info("CPU%d:\n", smp_processor_id()); |
9cb8f069 | 241 | show_stack(NULL, NULL, KERN_INFO); |
6ac972dd | 242 | raw_spin_unlock_irqrestore(&show_lock, flags); |
5045bcae RR |
243 | } |
244 | ||
245 | static void sysrq_showregs_othercpus(struct work_struct *dummy) | |
246 | { | |
8b604d52 | 247 | smp_call_function(showacpu, NULL, 0); |
5045bcae RR |
248 | } |
249 | ||
250 | static DECLARE_WORK(sysrq_showallcpus, sysrq_showregs_othercpus); | |
251 | ||
bcb48185 | 252 | static void sysrq_handle_showallcpus(u8 key) |
5045bcae | 253 | { |
47cab6a7 IM |
254 | /* |
255 | * Fall back to the workqueue based printing if the | |
256 | * backtrace printing did not succeed or the | |
257 | * architecture has no support for it: | |
258 | */ | |
259 | if (!trigger_all_cpu_backtrace()) { | |
b00bebbc | 260 | struct pt_regs *regs = NULL; |
47cab6a7 | 261 | |
1143637f | 262 | if (in_hardirq()) |
b00bebbc | 263 | regs = get_irq_regs(); |
5390e7f4 | 264 | |
dd976a97 | 265 | pr_info("CPU%d:\n", get_cpu()); |
5390e7f4 | 266 | if (regs) |
47cab6a7 | 267 | show_regs(regs); |
5390e7f4 CD |
268 | else |
269 | show_stack(NULL, NULL, KERN_INFO); | |
270 | ||
47cab6a7 | 271 | schedule_work(&sysrq_showallcpus); |
dd976a97 | 272 | put_cpu(); |
47cab6a7 | 273 | } |
5045bcae RR |
274 | } |
275 | ||
7fffe31d | 276 | static const struct sysrq_key_op sysrq_showallcpus_op = { |
5045bcae | 277 | .handler = sysrq_handle_showallcpus, |
afa80ccb | 278 | .help_msg = "show-backtrace-all-active-cpus(l)", |
5045bcae RR |
279 | .action_msg = "Show backtrace of all active CPUs", |
280 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
281 | }; | |
8ec8719f JW |
282 | #else |
283 | #define sysrq_showallcpus_op (*(const struct sysrq_key_op *)NULL) | |
5045bcae RR |
284 | #endif |
285 | ||
bcb48185 | 286 | static void sysrq_handle_showregs(u8 key) |
1da177e4 | 287 | { |
b00bebbc JX |
288 | struct pt_regs *regs = NULL; |
289 | ||
1143637f | 290 | if (in_hardirq()) |
b00bebbc | 291 | regs = get_irq_regs(); |
7d12e780 DH |
292 | if (regs) |
293 | show_regs(regs); | |
cdd6c482 | 294 | perf_event_print_debug(); |
1da177e4 | 295 | } |
7fffe31d | 296 | static const struct sysrq_key_op sysrq_showregs_op = { |
1da177e4 | 297 | .handler = sysrq_handle_showregs, |
afa80ccb | 298 | .help_msg = "show-registers(p)", |
1da177e4 LT |
299 | .action_msg = "Show Regs", |
300 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
301 | }; | |
302 | ||
bcb48185 | 303 | static void sysrq_handle_showstate(u8 key) |
1da177e4 LT |
304 | { |
305 | show_state(); | |
55df0933 | 306 | show_all_workqueues(); |
1da177e4 | 307 | } |
7fffe31d | 308 | static const struct sysrq_key_op sysrq_showstate_op = { |
1da177e4 | 309 | .handler = sysrq_handle_showstate, |
afa80ccb | 310 | .help_msg = "show-task-states(t)", |
1da177e4 LT |
311 | .action_msg = "Show State", |
312 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
313 | }; | |
314 | ||
bcb48185 | 315 | static void sysrq_handle_showstate_blocked(u8 key) |
e59e2ae2 IM |
316 | { |
317 | show_state_filter(TASK_UNINTERRUPTIBLE); | |
318 | } | |
7fffe31d | 319 | static const struct sysrq_key_op sysrq_showstate_blocked_op = { |
e59e2ae2 | 320 | .handler = sysrq_handle_showstate_blocked, |
afa80ccb | 321 | .help_msg = "show-blocked-tasks(w)", |
e59e2ae2 IM |
322 | .action_msg = "Show Blocked State", |
323 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
324 | }; | |
325 | ||
69f698ad PZ |
326 | #ifdef CONFIG_TRACING |
327 | #include <linux/ftrace.h> | |
328 | ||
bcb48185 | 329 | static void sysrq_ftrace_dump(u8 key) |
69f698ad | 330 | { |
cecbca96 | 331 | ftrace_dump(DUMP_ALL); |
69f698ad | 332 | } |
7fffe31d | 333 | static const struct sysrq_key_op sysrq_ftrace_dump_op = { |
69f698ad | 334 | .handler = sysrq_ftrace_dump, |
afa80ccb | 335 | .help_msg = "dump-ftrace-buffer(z)", |
69f698ad PZ |
336 | .action_msg = "Dump ftrace buffer", |
337 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
338 | }; | |
339 | #else | |
7fffe31d | 340 | #define sysrq_ftrace_dump_op (*(const struct sysrq_key_op *)NULL) |
69f698ad | 341 | #endif |
e59e2ae2 | 342 | |
bcb48185 | 343 | static void sysrq_handle_showmem(u8 key) |
1da177e4 | 344 | { |
527ed4f7 | 345 | show_mem(); |
1da177e4 | 346 | } |
7fffe31d | 347 | static const struct sysrq_key_op sysrq_showmem_op = { |
1da177e4 | 348 | .handler = sysrq_handle_showmem, |
afa80ccb | 349 | .help_msg = "show-memory-usage(m)", |
1da177e4 LT |
350 | .action_msg = "Show Memory", |
351 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
352 | }; | |
353 | ||
bf36b901 AM |
354 | /* |
355 | * Signal sysrq helper function. Sends a signal to all user processes. | |
356 | */ | |
1da177e4 LT |
357 | static void send_sig_all(int sig) |
358 | { | |
359 | struct task_struct *p; | |
360 | ||
e502babe | 361 | read_lock(&tasklist_lock); |
1da177e4 | 362 | for_each_process(p) { |
d3a532a9 AV |
363 | if (p->flags & PF_KTHREAD) |
364 | continue; | |
365 | if (is_global_init(p)) | |
366 | continue; | |
367 | ||
b16503ba | 368 | do_send_sig_info(sig, SEND_SIG_PRIV, p, PIDTYPE_MAX); |
1da177e4 | 369 | } |
e502babe | 370 | read_unlock(&tasklist_lock); |
1da177e4 LT |
371 | } |
372 | ||
bcb48185 | 373 | static void sysrq_handle_term(u8 key) |
1da177e4 LT |
374 | { |
375 | send_sig_all(SIGTERM); | |
a8fe19eb | 376 | console_loglevel = CONSOLE_LOGLEVEL_DEBUG; |
1da177e4 | 377 | } |
7fffe31d | 378 | static const struct sysrq_key_op sysrq_term_op = { |
1da177e4 | 379 | .handler = sysrq_handle_term, |
afa80ccb | 380 | .help_msg = "terminate-all-tasks(e)", |
1da177e4 LT |
381 | .action_msg = "Terminate All Tasks", |
382 | .enable_mask = SYSRQ_ENABLE_SIGNAL, | |
383 | }; | |
384 | ||
65f27f38 | 385 | static void moom_callback(struct work_struct *ignored) |
1da177e4 | 386 | { |
6e0fc46d DR |
387 | const gfp_t gfp_mask = GFP_KERNEL; |
388 | struct oom_control oc = { | |
389 | .zonelist = node_zonelist(first_memory_node, gfp_mask), | |
390 | .nodemask = NULL, | |
2a966b77 | 391 | .memcg = NULL, |
6e0fc46d | 392 | .gfp_mask = gfp_mask, |
54e9e291 | 393 | .order = -1, |
6e0fc46d DR |
394 | }; |
395 | ||
dc56401f | 396 | mutex_lock(&oom_lock); |
6e0fc46d | 397 | if (!out_of_memory(&oc)) |
d75da004 | 398 | pr_info("OOM request ignored. No task eligible\n"); |
dc56401f | 399 | mutex_unlock(&oom_lock); |
1da177e4 LT |
400 | } |
401 | ||
65f27f38 | 402 | static DECLARE_WORK(moom_work, moom_callback); |
1da177e4 | 403 | |
bcb48185 | 404 | static void sysrq_handle_moom(u8 key) |
1da177e4 LT |
405 | { |
406 | schedule_work(&moom_work); | |
407 | } | |
7fffe31d | 408 | static const struct sysrq_key_op sysrq_moom_op = { |
1da177e4 | 409 | .handler = sysrq_handle_moom, |
afa80ccb | 410 | .help_msg = "memory-full-oom-kill(f)", |
1da177e4 | 411 | .action_msg = "Manual OOM execution", |
b4236f81 | 412 | .enable_mask = SYSRQ_ENABLE_SIGNAL, |
1da177e4 LT |
413 | }; |
414 | ||
8ec8719f | 415 | #ifdef CONFIG_BLOCK |
bcb48185 | 416 | static void sysrq_handle_thaw(u8 key) |
c2d75438 ES |
417 | { |
418 | emergency_thaw_all(); | |
419 | } | |
7fffe31d | 420 | static const struct sysrq_key_op sysrq_thaw_op = { |
c2d75438 | 421 | .handler = sysrq_handle_thaw, |
afa80ccb | 422 | .help_msg = "thaw-filesystems(j)", |
c2d75438 ES |
423 | .action_msg = "Emergency Thaw of all frozen filesystems", |
424 | .enable_mask = SYSRQ_ENABLE_SIGNAL, | |
425 | }; | |
8ec8719f JW |
426 | #else |
427 | #define sysrq_thaw_op (*(const struct sysrq_key_op *)NULL) | |
428 | #endif | |
c2d75438 | 429 | |
bcb48185 | 430 | static void sysrq_handle_kill(u8 key) |
1da177e4 LT |
431 | { |
432 | send_sig_all(SIGKILL); | |
a8fe19eb | 433 | console_loglevel = CONSOLE_LOGLEVEL_DEBUG; |
1da177e4 | 434 | } |
7fffe31d | 435 | static const struct sysrq_key_op sysrq_kill_op = { |
1da177e4 | 436 | .handler = sysrq_handle_kill, |
afa80ccb | 437 | .help_msg = "kill-all-tasks(i)", |
1da177e4 LT |
438 | .action_msg = "Kill All Tasks", |
439 | .enable_mask = SYSRQ_ENABLE_SIGNAL, | |
440 | }; | |
441 | ||
bcb48185 | 442 | static void sysrq_handle_unrt(u8 key) |
1da177e4 LT |
443 | { |
444 | normalize_rt_tasks(); | |
445 | } | |
7fffe31d | 446 | static const struct sysrq_key_op sysrq_unrt_op = { |
1da177e4 | 447 | .handler = sysrq_handle_unrt, |
afa80ccb | 448 | .help_msg = "nice-all-RT-tasks(n)", |
1da177e4 LT |
449 | .action_msg = "Nice All RT Tasks", |
450 | .enable_mask = SYSRQ_ENABLE_RTNICE, | |
451 | }; | |
452 | ||
453 | /* Key Operations table and lock */ | |
454 | static DEFINE_SPINLOCK(sysrq_key_table_lock); | |
bf36b901 | 455 | |
a27eb0cb | 456 | static const struct sysrq_key_op *sysrq_key_table[62] = { |
bf36b901 AM |
457 | &sysrq_loglevel_op, /* 0 */ |
458 | &sysrq_loglevel_op, /* 1 */ | |
459 | &sysrq_loglevel_op, /* 2 */ | |
460 | &sysrq_loglevel_op, /* 3 */ | |
461 | &sysrq_loglevel_op, /* 4 */ | |
462 | &sysrq_loglevel_op, /* 5 */ | |
463 | &sysrq_loglevel_op, /* 6 */ | |
464 | &sysrq_loglevel_op, /* 7 */ | |
465 | &sysrq_loglevel_op, /* 8 */ | |
466 | &sysrq_loglevel_op, /* 9 */ | |
467 | ||
468 | /* | |
d346cce3 RD |
469 | * a: Don't use for system provided sysrqs, it is handled specially on |
470 | * sparc and will never arrive. | |
bf36b901 AM |
471 | */ |
472 | NULL, /* a */ | |
473 | &sysrq_reboot_op, /* b */ | |
5e351410 | 474 | &sysrq_crash_op, /* c */ |
bf36b901 AM |
475 | &sysrq_showlocks_op, /* d */ |
476 | &sysrq_term_op, /* e */ | |
477 | &sysrq_moom_op, /* f */ | |
364b5b7b | 478 | /* g: May be registered for the kernel debugger */ |
bf36b901 | 479 | NULL, /* g */ |
c2d75438 | 480 | NULL, /* h - reserved for help */ |
bf36b901 | 481 | &sysrq_kill_op, /* i */ |
c2d75438 | 482 | &sysrq_thaw_op, /* j */ |
bf36b901 | 483 | &sysrq_SAK_op, /* k */ |
5045bcae | 484 | &sysrq_showallcpus_op, /* l */ |
bf36b901 AM |
485 | &sysrq_showmem_op, /* m */ |
486 | &sysrq_unrt_op, /* n */ | |
d346cce3 | 487 | /* o: This will often be registered as 'Off' at init time */ |
bf36b901 AM |
488 | NULL, /* o */ |
489 | &sysrq_showregs_op, /* p */ | |
88ad0bf6 | 490 | &sysrq_show_timers_op, /* q */ |
d346cce3 | 491 | &sysrq_unraw_op, /* r */ |
bf36b901 AM |
492 | &sysrq_sync_op, /* s */ |
493 | &sysrq_showstate_op, /* t */ | |
494 | &sysrq_mountro_op, /* u */ | |
364b5b7b | 495 | /* v: May be registered for frame buffer console restore */ |
bf36b901 | 496 | NULL, /* v */ |
d346cce3 | 497 | &sysrq_showstate_blocked_op, /* w */ |
d1e9a4f5 | 498 | /* x: May be registered on mips for TLB dump */ |
d346cce3 | 499 | /* x: May be registered on ppc/powerpc for xmon */ |
916ca14a | 500 | /* x: May be registered on sparc64 for global PMU dump */ |
d346cce3 | 501 | NULL, /* x */ |
93dae5b7 | 502 | /* y: May be registered on sparc64 for global register dump */ |
bf36b901 | 503 | NULL, /* y */ |
69f698ad | 504 | &sysrq_ftrace_dump_op, /* z */ |
a27eb0cb AP |
505 | NULL, /* A */ |
506 | NULL, /* B */ | |
507 | NULL, /* C */ | |
508 | NULL, /* D */ | |
509 | NULL, /* E */ | |
510 | NULL, /* F */ | |
511 | NULL, /* G */ | |
512 | NULL, /* H */ | |
513 | NULL, /* I */ | |
514 | NULL, /* J */ | |
515 | NULL, /* K */ | |
516 | NULL, /* L */ | |
517 | NULL, /* M */ | |
518 | NULL, /* N */ | |
519 | NULL, /* O */ | |
520 | NULL, /* P */ | |
521 | NULL, /* Q */ | |
522 | NULL, /* R */ | |
523 | NULL, /* S */ | |
524 | NULL, /* T */ | |
525 | NULL, /* U */ | |
526 | NULL, /* V */ | |
527 | NULL, /* W */ | |
528 | NULL, /* X */ | |
529 | NULL, /* Y */ | |
530 | NULL, /* Z */ | |
1da177e4 LT |
531 | }; |
532 | ||
533 | /* key2index calculation, -1 on invalid index */ | |
8ac20a03 | 534 | static int sysrq_key_table_key2index(u8 key) |
bf36b901 | 535 | { |
a27f3b72 JS |
536 | switch (key) { |
537 | case '0' ... '9': | |
538 | return key - '0'; | |
539 | case 'a' ... 'z': | |
540 | return key - 'a' + 10; | |
541 | case 'A' ... 'Z': | |
542 | return key - 'A' + 10 + 26; | |
543 | default: | |
544 | return -1; | |
545 | } | |
1da177e4 LT |
546 | } |
547 | ||
548 | /* | |
549 | * get and put functions for the table, exposed to modules. | |
550 | */ | |
8ac20a03 | 551 | static const struct sysrq_key_op *__sysrq_get_key_op(u8 key) |
bf36b901 | 552 | { |
149ad2c6 XT |
553 | const struct sysrq_key_op *op_p = NULL; |
554 | int i; | |
bf36b901 | 555 | |
1da177e4 | 556 | i = sysrq_key_table_key2index(key); |
bf36b901 | 557 | if (i != -1) |
149ad2c6 | 558 | op_p = sysrq_key_table[i]; |
97f5f0cd | 559 | |
149ad2c6 | 560 | return op_p; |
1da177e4 LT |
561 | } |
562 | ||
8ac20a03 | 563 | static void __sysrq_put_key_op(u8 key, const struct sysrq_key_op *op_p) |
bf36b901 | 564 | { |
149ad2c6 | 565 | int i = sysrq_key_table_key2index(key); |
1da177e4 | 566 | |
149ad2c6 XT |
567 | if (i != -1) |
568 | sysrq_key_table[i] = op_p; | |
1da177e4 LT |
569 | } |
570 | ||
8ac20a03 | 571 | void __handle_sysrq(u8 key, bool check_mask) |
1da177e4 | 572 | { |
23cbedf8 | 573 | const struct sysrq_key_op *op_p; |
1da177e4 | 574 | int orig_log_level; |
c39ea0b9 | 575 | int orig_suppress_printk; |
bf36b901 | 576 | int i; |
1da177e4 | 577 | |
c39ea0b9 FT |
578 | orig_suppress_printk = suppress_printk; |
579 | suppress_printk = 0; | |
580 | ||
722773af | 581 | rcu_sysrq_start(); |
984d74a7 | 582 | rcu_read_lock(); |
fb144adc AW |
583 | /* |
584 | * Raise the apparent loglevel to maximum so that the sysrq header | |
585 | * is shown to provide the user with positive feedback. We do not | |
586 | * simply emit this at KERN_EMERG as that would change message | |
587 | * routing in the consumers of /proc/kmsg. | |
588 | */ | |
1da177e4 | 589 | orig_log_level = console_loglevel; |
a8fe19eb | 590 | console_loglevel = CONSOLE_LOGLEVEL_DEFAULT; |
1da177e4 | 591 | |
149ad2c6 XT |
592 | op_p = __sysrq_get_key_op(key); |
593 | if (op_p) { | |
bf36b901 AM |
594 | /* |
595 | * Should we check for enabled operations (/proc/sysrq-trigger | |
596 | * should not) and is the invoked operation enabled? | |
597 | */ | |
5d6f647f | 598 | if (!check_mask || sysrq_on_mask(op_p->enable_mask)) { |
c3fee609 | 599 | pr_info("%s\n", op_p->action_msg); |
1da177e4 | 600 | console_loglevel = orig_log_level; |
1495cc9d | 601 | op_p->handler(key); |
bf36b901 | 602 | } else { |
c3fee609 | 603 | pr_info("This sysrq operation is disabled.\n"); |
075e1a0c | 604 | console_loglevel = orig_log_level; |
bf36b901 | 605 | } |
1da177e4 | 606 | } else { |
c3fee609 | 607 | pr_info("HELP : "); |
1da177e4 | 608 | /* Only print the help msg once per handler */ |
bf36b901 AM |
609 | for (i = 0; i < ARRAY_SIZE(sysrq_key_table); i++) { |
610 | if (sysrq_key_table[i]) { | |
611 | int j; | |
612 | ||
613 | for (j = 0; sysrq_key_table[i] != | |
614 | sysrq_key_table[j]; j++) | |
615 | ; | |
616 | if (j != i) | |
617 | continue; | |
401e4a7c | 618 | pr_cont("%s ", sysrq_key_table[i]->help_msg); |
bf36b901 | 619 | } |
1da177e4 | 620 | } |
401e4a7c | 621 | pr_cont("\n"); |
1da177e4 LT |
622 | console_loglevel = orig_log_level; |
623 | } | |
984d74a7 | 624 | rcu_read_unlock(); |
722773af | 625 | rcu_sysrq_end(); |
c39ea0b9 FT |
626 | |
627 | suppress_printk = orig_suppress_printk; | |
1da177e4 LT |
628 | } |
629 | ||
8ac20a03 | 630 | void handle_sysrq(u8 key) |
1da177e4 | 631 | { |
5d6f647f | 632 | if (sysrq_on()) |
f335397d | 633 | __handle_sysrq(key, true); |
1da177e4 | 634 | } |
bf36b901 | 635 | EXPORT_SYMBOL(handle_sysrq); |
1da177e4 | 636 | |
97f5f0cd | 637 | #ifdef CONFIG_INPUT |
ffb6e0c9 | 638 | static int sysrq_reset_downtime_ms; |
97f5f0cd DT |
639 | |
640 | /* Simple translation table for the SysRq keys */ | |
fcb71930 | 641 | static const unsigned char sysrq_xlate[KEY_CNT] = |
149ad2c6 XT |
642 | "\000\0331234567890-=\177\t" /* 0x00 - 0x0f */ |
643 | "qwertyuiop[]\r\000as" /* 0x10 - 0x1f */ | |
644 | "dfghjkl;'`\000\\zxcv" /* 0x20 - 0x2f */ | |
645 | "bnm,./\000*\000 \000\201\202\203\204\205" /* 0x30 - 0x3f */ | |
646 | "\206\207\210\211\212\000\000789-456+1" /* 0x40 - 0x4f */ | |
647 | "230\177\000\000\213\214\000\000\000\000\000\000\000\000\000\000" /* 0x50 - 0x5f */ | |
648 | "\r\000/"; /* 0x60 - 0x6f */ | |
97f5f0cd | 649 | |
fcb71930 DT |
650 | struct sysrq_state { |
651 | struct input_handle handle; | |
652 | struct work_struct reinject_work; | |
653 | unsigned long key_down[BITS_TO_LONGS(KEY_CNT)]; | |
654 | unsigned int alt; | |
655 | unsigned int alt_use; | |
a27eb0cb AP |
656 | unsigned int shift; |
657 | unsigned int shift_use; | |
fcb71930 DT |
658 | bool active; |
659 | bool need_reinject; | |
7ab7b5ad | 660 | bool reinjecting; |
154b7a48 MP |
661 | |
662 | /* reset sequence handling */ | |
663 | bool reset_canceled; | |
3d289517 | 664 | bool reset_requested; |
154b7a48 MP |
665 | unsigned long reset_keybit[BITS_TO_LONGS(KEY_CNT)]; |
666 | int reset_seq_len; | |
667 | int reset_seq_cnt; | |
668 | int reset_seq_version; | |
39030786 | 669 | struct timer_list keyreset_timer; |
fcb71930 DT |
670 | }; |
671 | ||
154b7a48 MP |
672 | #define SYSRQ_KEY_RESET_MAX 20 /* Should be plenty */ |
673 | static unsigned short sysrq_reset_seq[SYSRQ_KEY_RESET_MAX]; | |
674 | static unsigned int sysrq_reset_seq_len; | |
675 | static unsigned int sysrq_reset_seq_version = 1; | |
676 | ||
677 | static void sysrq_parse_reset_sequence(struct sysrq_state *state) | |
678 | { | |
679 | int i; | |
680 | unsigned short key; | |
681 | ||
682 | state->reset_seq_cnt = 0; | |
683 | ||
684 | for (i = 0; i < sysrq_reset_seq_len; i++) { | |
685 | key = sysrq_reset_seq[i]; | |
686 | ||
687 | if (key == KEY_RESERVED || key > KEY_MAX) | |
688 | break; | |
689 | ||
690 | __set_bit(key, state->reset_keybit); | |
691 | state->reset_seq_len++; | |
692 | ||
693 | if (test_bit(key, state->key_down)) | |
694 | state->reset_seq_cnt++; | |
695 | } | |
696 | ||
697 | /* Disable reset until old keys are not released */ | |
698 | state->reset_canceled = state->reset_seq_cnt != 0; | |
699 | ||
700 | state->reset_seq_version = sysrq_reset_seq_version; | |
701 | } | |
702 | ||
8c318fa9 | 703 | static void sysrq_do_reset(struct timer_list *t) |
39030786 | 704 | { |
8c318fa9 | 705 | struct sysrq_state *state = from_timer(state, t, keyreset_timer); |
3d289517 MP |
706 | |
707 | state->reset_requested = true; | |
708 | ||
8fefbc6d | 709 | orderly_reboot(); |
39030786 MP |
710 | } |
711 | ||
712 | static void sysrq_handle_reset_request(struct sysrq_state *state) | |
713 | { | |
3d289517 MP |
714 | if (state->reset_requested) |
715 | __handle_sysrq(sysrq_xlate[KEY_B], false); | |
716 | ||
39030786 MP |
717 | if (sysrq_reset_downtime_ms) |
718 | mod_timer(&state->keyreset_timer, | |
719 | jiffies + msecs_to_jiffies(sysrq_reset_downtime_ms)); | |
720 | else | |
8c318fa9 | 721 | sysrq_do_reset(&state->keyreset_timer); |
39030786 MP |
722 | } |
723 | ||
724 | static void sysrq_detect_reset_sequence(struct sysrq_state *state, | |
154b7a48 MP |
725 | unsigned int code, int value) |
726 | { | |
727 | if (!test_bit(code, state->reset_keybit)) { | |
728 | /* | |
729 | * Pressing any key _not_ in reset sequence cancels | |
39030786 MP |
730 | * the reset sequence. Also cancelling the timer in |
731 | * case additional keys were pressed after a reset | |
732 | * has been requested. | |
154b7a48 | 733 | */ |
39030786 | 734 | if (value && state->reset_seq_cnt) { |
154b7a48 | 735 | state->reset_canceled = true; |
39030786 MP |
736 | del_timer(&state->keyreset_timer); |
737 | } | |
154b7a48 | 738 | } else if (value == 0) { |
39030786 MP |
739 | /* |
740 | * Key release - all keys in the reset sequence need | |
741 | * to be pressed and held for the reset timeout | |
742 | * to hold. | |
743 | */ | |
744 | del_timer(&state->keyreset_timer); | |
745 | ||
154b7a48 MP |
746 | if (--state->reset_seq_cnt == 0) |
747 | state->reset_canceled = false; | |
748 | } else if (value == 1) { | |
749 | /* key press, not autorepeat */ | |
750 | if (++state->reset_seq_cnt == state->reset_seq_len && | |
751 | !state->reset_canceled) { | |
39030786 | 752 | sysrq_handle_reset_request(state); |
154b7a48 MP |
753 | } |
754 | } | |
154b7a48 MP |
755 | } |
756 | ||
4c076eb0 MP |
757 | #ifdef CONFIG_OF |
758 | static void sysrq_of_get_keyreset_config(void) | |
759 | { | |
760 | u32 key; | |
761 | struct device_node *np; | |
762 | struct property *prop; | |
763 | const __be32 *p; | |
764 | ||
765 | np = of_find_node_by_path("/chosen/linux,sysrq-reset-seq"); | |
766 | if (!np) { | |
767 | pr_debug("No sysrq node found"); | |
768 | return; | |
769 | } | |
770 | ||
771 | /* Reset in case a __weak definition was present */ | |
772 | sysrq_reset_seq_len = 0; | |
773 | ||
774 | of_property_for_each_u32(np, "keyset", prop, p, key) { | |
775 | if (key == KEY_RESERVED || key > KEY_MAX || | |
776 | sysrq_reset_seq_len == SYSRQ_KEY_RESET_MAX) | |
777 | break; | |
778 | ||
779 | sysrq_reset_seq[sysrq_reset_seq_len++] = (unsigned short)key; | |
780 | } | |
781 | ||
782 | /* Get reset timeout if any. */ | |
783 | of_property_read_u32(np, "timeout-ms", &sysrq_reset_downtime_ms); | |
279070b9 YL |
784 | |
785 | of_node_put(np); | |
4c076eb0 MP |
786 | } |
787 | #else | |
788 | static void sysrq_of_get_keyreset_config(void) | |
789 | { | |
790 | } | |
791 | #endif | |
792 | ||
fcb71930 DT |
793 | static void sysrq_reinject_alt_sysrq(struct work_struct *work) |
794 | { | |
795 | struct sysrq_state *sysrq = | |
796 | container_of(work, struct sysrq_state, reinject_work); | |
797 | struct input_handle *handle = &sysrq->handle; | |
798 | unsigned int alt_code = sysrq->alt_use; | |
799 | ||
800 | if (sysrq->need_reinject) { | |
7ab7b5ad DT |
801 | /* we do not want the assignment to be reordered */ |
802 | sysrq->reinjecting = true; | |
803 | mb(); | |
804 | ||
fcb71930 DT |
805 | /* Simulate press and release of Alt + SysRq */ |
806 | input_inject_event(handle, EV_KEY, alt_code, 1); | |
807 | input_inject_event(handle, EV_KEY, KEY_SYSRQ, 1); | |
808 | input_inject_event(handle, EV_SYN, SYN_REPORT, 1); | |
809 | ||
810 | input_inject_event(handle, EV_KEY, KEY_SYSRQ, 0); | |
811 | input_inject_event(handle, EV_KEY, alt_code, 0); | |
812 | input_inject_event(handle, EV_SYN, SYN_REPORT, 1); | |
7ab7b5ad DT |
813 | |
814 | mb(); | |
815 | sysrq->reinjecting = false; | |
fcb71930 DT |
816 | } |
817 | } | |
97f5f0cd | 818 | |
154b7a48 MP |
819 | static bool sysrq_handle_keypress(struct sysrq_state *sysrq, |
820 | unsigned int code, int value) | |
97f5f0cd | 821 | { |
fcb71930 | 822 | bool was_active = sysrq->active; |
1966cb22 DT |
823 | bool suppress; |
824 | ||
154b7a48 | 825 | switch (code) { |
7ab7b5ad | 826 | |
154b7a48 MP |
827 | case KEY_LEFTALT: |
828 | case KEY_RIGHTALT: | |
829 | if (!value) { | |
830 | /* One of ALTs is being released */ | |
831 | if (sysrq->active && code == sysrq->alt_use) | |
832 | sysrq->active = false; | |
1966cb22 | 833 | |
154b7a48 MP |
834 | sysrq->alt = KEY_RESERVED; |
835 | ||
836 | } else if (value != 2) { | |
837 | sysrq->alt = code; | |
838 | sysrq->need_reinject = false; | |
839 | } | |
fcb71930 | 840 | break; |
97f5f0cd | 841 | |
a27eb0cb AP |
842 | case KEY_LEFTSHIFT: |
843 | case KEY_RIGHTSHIFT: | |
844 | if (!value) | |
845 | sysrq->shift = KEY_RESERVED; | |
846 | else if (value != 2) | |
847 | sysrq->shift = code; | |
3aee752c OP |
848 | if (sysrq->active) |
849 | sysrq->shift_use = sysrq->shift; | |
a27eb0cb AP |
850 | break; |
851 | ||
154b7a48 MP |
852 | case KEY_SYSRQ: |
853 | if (value == 1 && sysrq->alt != KEY_RESERVED) { | |
854 | sysrq->active = true; | |
855 | sysrq->alt_use = sysrq->alt; | |
a27eb0cb AP |
856 | /* either RESERVED (for released) or actual code */ |
857 | sysrq->shift_use = sysrq->shift; | |
154b7a48 MP |
858 | /* |
859 | * If nothing else will be pressed we'll need | |
860 | * to re-inject Alt-SysRq keysroke. | |
861 | */ | |
862 | sysrq->need_reinject = true; | |
863 | } | |
97f5f0cd | 864 | |
154b7a48 MP |
865 | /* |
866 | * Pretend that sysrq was never pressed at all. This | |
867 | * is needed to properly handle KGDB which will try | |
868 | * to release all keys after exiting debugger. If we | |
869 | * do not clear key bit it KGDB will end up sending | |
870 | * release events for Alt and SysRq, potentially | |
871 | * triggering print screen function. | |
872 | */ | |
873 | if (sysrq->active) | |
874 | clear_bit(KEY_SYSRQ, sysrq->handle.dev->key); | |
f5dec511 | 875 | |
154b7a48 | 876 | break; |
fcb71930 | 877 | |
154b7a48 MP |
878 | default: |
879 | if (sysrq->active && value && value != 2) { | |
a27eb0cb AP |
880 | unsigned char c = sysrq_xlate[code]; |
881 | ||
154b7a48 | 882 | sysrq->need_reinject = false; |
a27eb0cb AP |
883 | if (sysrq->shift_use != KEY_RESERVED) |
884 | c = toupper(c); | |
885 | __handle_sysrq(c, true); | |
154b7a48 MP |
886 | } |
887 | break; | |
888 | } | |
fcb71930 | 889 | |
154b7a48 | 890 | suppress = sysrq->active; |
fcb71930 | 891 | |
154b7a48 | 892 | if (!sysrq->active) { |
fcb71930 | 893 | |
154b7a48 MP |
894 | /* |
895 | * See if reset sequence has changed since the last time. | |
896 | */ | |
897 | if (sysrq->reset_seq_version != sysrq_reset_seq_version) | |
898 | sysrq_parse_reset_sequence(sysrq); | |
fcb71930 | 899 | |
154b7a48 MP |
900 | /* |
901 | * If we are not suppressing key presses keep track of | |
902 | * keyboard state so we can release keys that have been | |
903 | * pressed before entering SysRq mode. | |
904 | */ | |
905 | if (value) | |
906 | set_bit(code, sysrq->key_down); | |
907 | else | |
908 | clear_bit(code, sysrq->key_down); | |
909 | ||
910 | if (was_active) | |
911 | schedule_work(&sysrq->reinject_work); | |
912 | ||
39030786 MP |
913 | /* Check for reset sequence */ |
914 | sysrq_detect_reset_sequence(sysrq, code, value); | |
97f5f0cd | 915 | |
154b7a48 MP |
916 | } else if (value == 0 && test_and_clear_bit(code, sysrq->key_down)) { |
917 | /* | |
918 | * Pass on release events for keys that was pressed before | |
919 | * entering SysRq mode. | |
920 | */ | |
921 | suppress = false; | |
922 | } | |
fcb71930 | 923 | |
154b7a48 MP |
924 | return suppress; |
925 | } | |
fcb71930 | 926 | |
154b7a48 MP |
927 | static bool sysrq_filter(struct input_handle *handle, |
928 | unsigned int type, unsigned int code, int value) | |
929 | { | |
930 | struct sysrq_state *sysrq = handle->private; | |
931 | bool suppress; | |
fcb71930 | 932 | |
154b7a48 MP |
933 | /* |
934 | * Do not filter anything if we are in the process of re-injecting | |
935 | * Alt+SysRq combination. | |
936 | */ | |
937 | if (sysrq->reinjecting) | |
938 | return false; | |
939 | ||
940 | switch (type) { | |
941 | ||
942 | case EV_SYN: | |
943 | suppress = false; | |
944 | break; | |
945 | ||
946 | case EV_KEY: | |
947 | suppress = sysrq_handle_keypress(sysrq, code, value); | |
97f5f0cd DT |
948 | break; |
949 | ||
950 | default: | |
fcb71930 | 951 | suppress = sysrq->active; |
97f5f0cd DT |
952 | break; |
953 | } | |
954 | ||
1966cb22 | 955 | return suppress; |
97f5f0cd DT |
956 | } |
957 | ||
958 | static int sysrq_connect(struct input_handler *handler, | |
959 | struct input_dev *dev, | |
960 | const struct input_device_id *id) | |
961 | { | |
fcb71930 | 962 | struct sysrq_state *sysrq; |
97f5f0cd DT |
963 | int error; |
964 | ||
fcb71930 DT |
965 | sysrq = kzalloc(sizeof(struct sysrq_state), GFP_KERNEL); |
966 | if (!sysrq) | |
97f5f0cd DT |
967 | return -ENOMEM; |
968 | ||
fcb71930 DT |
969 | INIT_WORK(&sysrq->reinject_work, sysrq_reinject_alt_sysrq); |
970 | ||
971 | sysrq->handle.dev = dev; | |
972 | sysrq->handle.handler = handler; | |
973 | sysrq->handle.name = "sysrq"; | |
974 | sysrq->handle.private = sysrq; | |
8c318fa9 | 975 | timer_setup(&sysrq->keyreset_timer, sysrq_do_reset, 0); |
97f5f0cd | 976 | |
fcb71930 | 977 | error = input_register_handle(&sysrq->handle); |
97f5f0cd DT |
978 | if (error) { |
979 | pr_err("Failed to register input sysrq handler, error %d\n", | |
980 | error); | |
981 | goto err_free; | |
982 | } | |
983 | ||
fcb71930 | 984 | error = input_open_device(&sysrq->handle); |
97f5f0cd DT |
985 | if (error) { |
986 | pr_err("Failed to open input device, error %d\n", error); | |
987 | goto err_unregister; | |
988 | } | |
989 | ||
990 | return 0; | |
991 | ||
992 | err_unregister: | |
fcb71930 | 993 | input_unregister_handle(&sysrq->handle); |
97f5f0cd | 994 | err_free: |
fcb71930 | 995 | kfree(sysrq); |
97f5f0cd DT |
996 | return error; |
997 | } | |
998 | ||
999 | static void sysrq_disconnect(struct input_handle *handle) | |
1000 | { | |
fcb71930 DT |
1001 | struct sysrq_state *sysrq = handle->private; |
1002 | ||
97f5f0cd | 1003 | input_close_device(handle); |
fcb71930 | 1004 | cancel_work_sync(&sysrq->reinject_work); |
292a089d | 1005 | timer_shutdown_sync(&sysrq->keyreset_timer); |
97f5f0cd | 1006 | input_unregister_handle(handle); |
fcb71930 | 1007 | kfree(sysrq); |
97f5f0cd DT |
1008 | } |
1009 | ||
1010 | /* | |
1966cb22 DT |
1011 | * We are matching on KEY_LEFTALT instead of KEY_SYSRQ because not all |
1012 | * keyboards have SysRq key predefined and so user may add it to keymap | |
97f5f0cd DT |
1013 | * later, but we expect all such keyboards to have left alt. |
1014 | */ | |
1015 | static const struct input_device_id sysrq_ids[] = { | |
1016 | { | |
1017 | .flags = INPUT_DEVICE_ID_MATCH_EVBIT | | |
1018 | INPUT_DEVICE_ID_MATCH_KEYBIT, | |
802c0388 AM |
1019 | .evbit = { [BIT_WORD(EV_KEY)] = BIT_MASK(EV_KEY) }, |
1020 | .keybit = { [BIT_WORD(KEY_LEFTALT)] = BIT_MASK(KEY_LEFTALT) }, | |
97f5f0cd DT |
1021 | }, |
1022 | { }, | |
1023 | }; | |
1024 | ||
1025 | static struct input_handler sysrq_handler = { | |
1026 | .filter = sysrq_filter, | |
1027 | .connect = sysrq_connect, | |
1028 | .disconnect = sysrq_disconnect, | |
1029 | .name = "sysrq", | |
1030 | .id_table = sysrq_ids, | |
1031 | }; | |
1032 | ||
97f5f0cd DT |
1033 | static inline void sysrq_register_handler(void) |
1034 | { | |
1035 | int error; | |
1036 | ||
4c076eb0 MP |
1037 | sysrq_of_get_keyreset_config(); |
1038 | ||
97f5f0cd DT |
1039 | error = input_register_handler(&sysrq_handler); |
1040 | if (error) | |
1041 | pr_err("Failed to register input handler, error %d", error); | |
97f5f0cd DT |
1042 | } |
1043 | ||
1044 | static inline void sysrq_unregister_handler(void) | |
1045 | { | |
f06327d1 | 1046 | input_unregister_handler(&sysrq_handler); |
97f5f0cd DT |
1047 | } |
1048 | ||
154b7a48 MP |
1049 | static int sysrq_reset_seq_param_set(const char *buffer, |
1050 | const struct kernel_param *kp) | |
1051 | { | |
1052 | unsigned long val; | |
1053 | int error; | |
1054 | ||
86b40567 | 1055 | error = kstrtoul(buffer, 0, &val); |
154b7a48 MP |
1056 | if (error < 0) |
1057 | return error; | |
1058 | ||
1059 | if (val > KEY_MAX) | |
1060 | return -EINVAL; | |
1061 | ||
1062 | *((unsigned short *)kp->arg) = val; | |
1063 | sysrq_reset_seq_version++; | |
1064 | ||
1065 | return 0; | |
1066 | } | |
1067 | ||
9c27847d | 1068 | static const struct kernel_param_ops param_ops_sysrq_reset_seq = { |
154b7a48 MP |
1069 | .get = param_get_ushort, |
1070 | .set = sysrq_reset_seq_param_set, | |
1071 | }; | |
1072 | ||
1073 | #define param_check_sysrq_reset_seq(name, p) \ | |
1074 | __param_check(name, p, unsigned short) | |
1075 | ||
3bce6f64 PG |
1076 | /* |
1077 | * not really modular, but the easiest way to keep compat with existing | |
1078 | * bootargs behaviour is to continue using module_param here. | |
1079 | */ | |
154b7a48 MP |
1080 | module_param_array_named(reset_seq, sysrq_reset_seq, sysrq_reset_seq, |
1081 | &sysrq_reset_seq_len, 0644); | |
1082 | ||
39030786 MP |
1083 | module_param_named(sysrq_downtime_ms, sysrq_reset_downtime_ms, int, 0644); |
1084 | ||
97f5f0cd DT |
1085 | #else |
1086 | ||
1087 | static inline void sysrq_register_handler(void) | |
1088 | { | |
1089 | } | |
1090 | ||
1091 | static inline void sysrq_unregister_handler(void) | |
1092 | { | |
1093 | } | |
1094 | ||
1095 | #endif /* CONFIG_INPUT */ | |
1096 | ||
1097 | int sysrq_toggle_support(int enable_mask) | |
1098 | { | |
1099 | bool was_enabled = sysrq_on(); | |
1100 | ||
1101 | sysrq_enabled = enable_mask; | |
1102 | ||
1103 | if (was_enabled != sysrq_on()) { | |
1104 | if (sysrq_on()) | |
1105 | sysrq_register_handler(); | |
1106 | else | |
1107 | sysrq_unregister_handler(); | |
1108 | } | |
1109 | ||
1110 | return 0; | |
1111 | } | |
66bb1c95 | 1112 | EXPORT_SYMBOL_GPL(sysrq_toggle_support); |
97f5f0cd | 1113 | |
8ac20a03 | 1114 | static int __sysrq_swap_key_ops(u8 key, const struct sysrq_key_op *insert_op_p, |
149ad2c6 | 1115 | const struct sysrq_key_op *remove_op_p) |
bf36b901 | 1116 | { |
1da177e4 | 1117 | int retval; |
1da177e4 | 1118 | |
984d74a7 | 1119 | spin_lock(&sysrq_key_table_lock); |
1da177e4 LT |
1120 | if (__sysrq_get_key_op(key) == remove_op_p) { |
1121 | __sysrq_put_key_op(key, insert_op_p); | |
1122 | retval = 0; | |
1123 | } else { | |
1124 | retval = -1; | |
1125 | } | |
984d74a7 RR |
1126 | spin_unlock(&sysrq_key_table_lock); |
1127 | ||
1128 | /* | |
1129 | * A concurrent __handle_sysrq either got the old op or the new op. | |
1130 | * Wait for it to go away before returning, so the code for an old | |
1131 | * op is not freed (eg. on module unload) while it is in use. | |
1132 | */ | |
1133 | synchronize_rcu(); | |
1134 | ||
1da177e4 LT |
1135 | return retval; |
1136 | } | |
1137 | ||
8ac20a03 | 1138 | int register_sysrq_key(u8 key, const struct sysrq_key_op *op_p) |
1da177e4 LT |
1139 | { |
1140 | return __sysrq_swap_key_ops(key, op_p, NULL); | |
1141 | } | |
bf36b901 | 1142 | EXPORT_SYMBOL(register_sysrq_key); |
1da177e4 | 1143 | |
8ac20a03 | 1144 | int unregister_sysrq_key(u8 key, const struct sysrq_key_op *op_p) |
1da177e4 LT |
1145 | { |
1146 | return __sysrq_swap_key_ops(key, NULL, op_p); | |
1147 | } | |
1da177e4 | 1148 | EXPORT_SYMBOL(unregister_sysrq_key); |
f40cbaa5 AD |
1149 | |
1150 | #ifdef CONFIG_PROC_FS | |
1151 | /* | |
1152 | * writing 'C' to /proc/sysrq-trigger is like sysrq-C | |
39ff20f5 TM |
1153 | * Normally, only the first character written is processed. |
1154 | * However, if the first character is an underscore, | |
1155 | * all characters are processed. | |
f40cbaa5 AD |
1156 | */ |
1157 | static ssize_t write_sysrq_trigger(struct file *file, const char __user *buf, | |
1158 | size_t count, loff_t *ppos) | |
1159 | { | |
39ff20f5 TM |
1160 | bool bulk = false; |
1161 | size_t i; | |
1162 | ||
1163 | for (i = 0; i < count; i++) { | |
f40cbaa5 AD |
1164 | char c; |
1165 | ||
39ff20f5 | 1166 | if (get_user(c, buf + i)) |
f40cbaa5 | 1167 | return -EFAULT; |
39ff20f5 TM |
1168 | |
1169 | if (c == '_') | |
1170 | bulk = true; | |
1171 | else | |
1172 | __handle_sysrq(c, false); | |
1173 | ||
1174 | if (!bulk) | |
1175 | break; | |
f40cbaa5 | 1176 | } |
97f5f0cd | 1177 | |
f40cbaa5 AD |
1178 | return count; |
1179 | } | |
1180 | ||
97a32539 AD |
1181 | static const struct proc_ops sysrq_trigger_proc_ops = { |
1182 | .proc_write = write_sysrq_trigger, | |
1183 | .proc_lseek = noop_llseek, | |
f40cbaa5 AD |
1184 | }; |
1185 | ||
97f5f0cd DT |
1186 | static void sysrq_init_procfs(void) |
1187 | { | |
1188 | if (!proc_create("sysrq-trigger", S_IWUSR, NULL, | |
97a32539 | 1189 | &sysrq_trigger_proc_ops)) |
97f5f0cd DT |
1190 | pr_err("Failed to register proc interface\n"); |
1191 | } | |
1192 | ||
1193 | #else | |
1194 | ||
1195 | static inline void sysrq_init_procfs(void) | |
1196 | { | |
1197 | } | |
1198 | ||
1199 | #endif /* CONFIG_PROC_FS */ | |
1200 | ||
f40cbaa5 AD |
1201 | static int __init sysrq_init(void) |
1202 | { | |
97f5f0cd DT |
1203 | sysrq_init_procfs(); |
1204 | ||
1205 | if (sysrq_on()) | |
1206 | sysrq_register_handler(); | |
1207 | ||
f40cbaa5 AD |
1208 | return 0; |
1209 | } | |
3bce6f64 | 1210 | device_initcall(sysrq_init); |