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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> |
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 | ||
66 | /* | |
67 | * A value of 1 means 'all', other nonzero values are an op mask: | |
68 | */ | |
97f5f0cd | 69 | static bool sysrq_on_mask(int mask) |
5d6f647f | 70 | { |
97f5f0cd DT |
71 | return sysrq_always_enabled || |
72 | sysrq_enabled == 1 || | |
73 | (sysrq_enabled & mask); | |
5d6f647f IM |
74 | } |
75 | ||
76 | static int __init sysrq_always_enabled_setup(char *str) | |
77 | { | |
97f5f0cd DT |
78 | sysrq_always_enabled = true; |
79 | pr_info("sysrq always enabled.\n"); | |
5d6f647f IM |
80 | |
81 | return 1; | |
82 | } | |
83 | ||
84 | __setup("sysrq_always_enabled", sysrq_always_enabled_setup); | |
85 | ||
1da177e4 | 86 | |
1495cc9d | 87 | static void sysrq_handle_loglevel(int key) |
1da177e4 LT |
88 | { |
89 | int i; | |
97f5f0cd | 90 | |
1da177e4 | 91 | i = key - '0'; |
a8fe19eb | 92 | console_loglevel = CONSOLE_LOGLEVEL_DEFAULT; |
401e4a7c | 93 | pr_info("Loglevel set to %d\n", i); |
1da177e4 | 94 | console_loglevel = i; |
bf36b901 | 95 | } |
1da177e4 LT |
96 | static struct sysrq_key_op sysrq_loglevel_op = { |
97 | .handler = sysrq_handle_loglevel, | |
208b95ce | 98 | .help_msg = "loglevel(0-9)", |
1da177e4 LT |
99 | .action_msg = "Changing Loglevel", |
100 | .enable_mask = SYSRQ_ENABLE_LOG, | |
101 | }; | |
102 | ||
1da177e4 | 103 | #ifdef CONFIG_VT |
1495cc9d | 104 | static void sysrq_handle_SAK(int key) |
1da177e4 | 105 | { |
8b6312f4 | 106 | struct work_struct *SAK_work = &vc_cons[fg_console].SAK_work; |
8b6312f4 | 107 | schedule_work(SAK_work); |
1da177e4 LT |
108 | } |
109 | static struct sysrq_key_op sysrq_SAK_op = { | |
110 | .handler = sysrq_handle_SAK, | |
afa80ccb | 111 | .help_msg = "sak(k)", |
1da177e4 LT |
112 | .action_msg = "SAK", |
113 | .enable_mask = SYSRQ_ENABLE_KEYBOARD, | |
114 | }; | |
bf36b901 | 115 | #else |
97f5f0cd | 116 | #define sysrq_SAK_op (*(struct sysrq_key_op *)NULL) |
1da177e4 LT |
117 | #endif |
118 | ||
119 | #ifdef CONFIG_VT | |
1495cc9d | 120 | static void sysrq_handle_unraw(int key) |
1da177e4 | 121 | { |
079c9534 | 122 | vt_reset_unicode(fg_console); |
1da177e4 | 123 | } |
079c9534 | 124 | |
1da177e4 LT |
125 | static struct sysrq_key_op sysrq_unraw_op = { |
126 | .handler = sysrq_handle_unraw, | |
afa80ccb | 127 | .help_msg = "unraw(r)", |
2e8ecb9d | 128 | .action_msg = "Keyboard mode set to system default", |
1da177e4 LT |
129 | .enable_mask = SYSRQ_ENABLE_KEYBOARD, |
130 | }; | |
bf36b901 | 131 | #else |
97f5f0cd | 132 | #define sysrq_unraw_op (*(struct sysrq_key_op *)NULL) |
1da177e4 LT |
133 | #endif /* CONFIG_VT */ |
134 | ||
1495cc9d | 135 | static void sysrq_handle_crash(int key) |
86b1ae38 | 136 | { |
d6580a9f | 137 | char *killer = NULL; |
cab8bd34 | 138 | |
984cf355 AS |
139 | /* we need to release the RCU read lock here, |
140 | * otherwise we get an annoying | |
141 | * 'BUG: sleeping function called from invalid context' | |
142 | * complaint from the kernel before the panic. | |
143 | */ | |
144 | rcu_read_unlock(); | |
cab8bd34 HS |
145 | panic_on_oops = 1; /* force panic */ |
146 | wmb(); | |
d6580a9f | 147 | *killer = 1; |
86b1ae38 | 148 | } |
cab8bd34 | 149 | static struct sysrq_key_op sysrq_crash_op = { |
d6580a9f | 150 | .handler = sysrq_handle_crash, |
afa80ccb | 151 | .help_msg = "crash(c)", |
d6580a9f | 152 | .action_msg = "Trigger a crash", |
86b1ae38 HN |
153 | .enable_mask = SYSRQ_ENABLE_DUMP, |
154 | }; | |
86b1ae38 | 155 | |
1495cc9d | 156 | static void sysrq_handle_reboot(int key) |
1da177e4 | 157 | { |
b2e9c7d0 | 158 | lockdep_off(); |
1da177e4 | 159 | local_irq_enable(); |
4de8b9b7 | 160 | emergency_restart(); |
1da177e4 | 161 | } |
1da177e4 LT |
162 | static struct sysrq_key_op sysrq_reboot_op = { |
163 | .handler = sysrq_handle_reboot, | |
afa80ccb | 164 | .help_msg = "reboot(b)", |
1da177e4 LT |
165 | .action_msg = "Resetting", |
166 | .enable_mask = SYSRQ_ENABLE_BOOT, | |
167 | }; | |
168 | ||
1495cc9d | 169 | static void sysrq_handle_sync(int key) |
1da177e4 LT |
170 | { |
171 | emergency_sync(); | |
172 | } | |
1da177e4 LT |
173 | static struct sysrq_key_op sysrq_sync_op = { |
174 | .handler = sysrq_handle_sync, | |
afa80ccb | 175 | .help_msg = "sync(s)", |
1da177e4 LT |
176 | .action_msg = "Emergency Sync", |
177 | .enable_mask = SYSRQ_ENABLE_SYNC, | |
178 | }; | |
179 | ||
1495cc9d | 180 | static void sysrq_handle_show_timers(int key) |
88ad0bf6 IM |
181 | { |
182 | sysrq_timer_list_show(); | |
183 | } | |
184 | ||
185 | static struct sysrq_key_op sysrq_show_timers_op = { | |
186 | .handler = sysrq_handle_show_timers, | |
afa80ccb | 187 | .help_msg = "show-all-timers(q)", |
322acf65 | 188 | .action_msg = "Show clockevent devices & pending hrtimers (no others)", |
88ad0bf6 IM |
189 | }; |
190 | ||
1495cc9d | 191 | static void sysrq_handle_mountro(int key) |
1da177e4 LT |
192 | { |
193 | emergency_remount(); | |
194 | } | |
1da177e4 LT |
195 | static struct sysrq_key_op sysrq_mountro_op = { |
196 | .handler = sysrq_handle_mountro, | |
afa80ccb | 197 | .help_msg = "unmount(u)", |
1da177e4 LT |
198 | .action_msg = "Emergency Remount R/O", |
199 | .enable_mask = SYSRQ_ENABLE_REMOUNT, | |
200 | }; | |
201 | ||
8c64580d | 202 | #ifdef CONFIG_LOCKDEP |
1495cc9d | 203 | static void sysrq_handle_showlocks(int key) |
de5097c2 | 204 | { |
9a11b49a | 205 | debug_show_all_locks(); |
de5097c2 | 206 | } |
8c64580d | 207 | |
de5097c2 IM |
208 | static struct sysrq_key_op sysrq_showlocks_op = { |
209 | .handler = sysrq_handle_showlocks, | |
afa80ccb | 210 | .help_msg = "show-all-locks(d)", |
de5097c2 IM |
211 | .action_msg = "Show Locks Held", |
212 | }; | |
bf36b901 | 213 | #else |
97f5f0cd | 214 | #define sysrq_showlocks_op (*(struct sysrq_key_op *)NULL) |
de5097c2 | 215 | #endif |
1da177e4 | 216 | |
5045bcae RR |
217 | #ifdef CONFIG_SMP |
218 | static DEFINE_SPINLOCK(show_lock); | |
219 | ||
220 | static void showacpu(void *dummy) | |
221 | { | |
222 | unsigned long flags; | |
223 | ||
224 | /* Idle CPUs have no interesting backtrace. */ | |
225 | if (idle_cpu(smp_processor_id())) | |
226 | return; | |
227 | ||
228 | spin_lock_irqsave(&show_lock, flags); | |
401e4a7c | 229 | pr_info("CPU%d:\n", smp_processor_id()); |
5045bcae RR |
230 | show_stack(NULL, NULL); |
231 | spin_unlock_irqrestore(&show_lock, flags); | |
232 | } | |
233 | ||
234 | static void sysrq_showregs_othercpus(struct work_struct *dummy) | |
235 | { | |
8b604d52 | 236 | smp_call_function(showacpu, NULL, 0); |
5045bcae RR |
237 | } |
238 | ||
239 | static DECLARE_WORK(sysrq_showallcpus, sysrq_showregs_othercpus); | |
240 | ||
1495cc9d | 241 | static void sysrq_handle_showallcpus(int key) |
5045bcae | 242 | { |
47cab6a7 IM |
243 | /* |
244 | * Fall back to the workqueue based printing if the | |
245 | * backtrace printing did not succeed or the | |
246 | * architecture has no support for it: | |
247 | */ | |
248 | if (!trigger_all_cpu_backtrace()) { | |
b00bebbc | 249 | struct pt_regs *regs = NULL; |
47cab6a7 | 250 | |
b00bebbc JX |
251 | if (in_irq()) |
252 | regs = get_irq_regs(); | |
47cab6a7 | 253 | if (regs) { |
401e4a7c | 254 | pr_info("CPU%d:\n", smp_processor_id()); |
47cab6a7 IM |
255 | show_regs(regs); |
256 | } | |
257 | schedule_work(&sysrq_showallcpus); | |
258 | } | |
5045bcae RR |
259 | } |
260 | ||
261 | static struct sysrq_key_op sysrq_showallcpus_op = { | |
262 | .handler = sysrq_handle_showallcpus, | |
afa80ccb | 263 | .help_msg = "show-backtrace-all-active-cpus(l)", |
5045bcae RR |
264 | .action_msg = "Show backtrace of all active CPUs", |
265 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
266 | }; | |
267 | #endif | |
268 | ||
1495cc9d | 269 | static void sysrq_handle_showregs(int key) |
1da177e4 | 270 | { |
b00bebbc JX |
271 | struct pt_regs *regs = NULL; |
272 | ||
273 | if (in_irq()) | |
274 | regs = get_irq_regs(); | |
7d12e780 DH |
275 | if (regs) |
276 | show_regs(regs); | |
cdd6c482 | 277 | perf_event_print_debug(); |
1da177e4 LT |
278 | } |
279 | static struct sysrq_key_op sysrq_showregs_op = { | |
280 | .handler = sysrq_handle_showregs, | |
afa80ccb | 281 | .help_msg = "show-registers(p)", |
1da177e4 LT |
282 | .action_msg = "Show Regs", |
283 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
284 | }; | |
285 | ||
1495cc9d | 286 | static void sysrq_handle_showstate(int key) |
1da177e4 LT |
287 | { |
288 | show_state(); | |
3494fc30 | 289 | show_workqueue_state(); |
1da177e4 LT |
290 | } |
291 | static struct sysrq_key_op sysrq_showstate_op = { | |
292 | .handler = sysrq_handle_showstate, | |
afa80ccb | 293 | .help_msg = "show-task-states(t)", |
1da177e4 LT |
294 | .action_msg = "Show State", |
295 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
296 | }; | |
297 | ||
1495cc9d | 298 | static void sysrq_handle_showstate_blocked(int key) |
e59e2ae2 IM |
299 | { |
300 | show_state_filter(TASK_UNINTERRUPTIBLE); | |
301 | } | |
302 | static struct sysrq_key_op sysrq_showstate_blocked_op = { | |
303 | .handler = sysrq_handle_showstate_blocked, | |
afa80ccb | 304 | .help_msg = "show-blocked-tasks(w)", |
e59e2ae2 IM |
305 | .action_msg = "Show Blocked State", |
306 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
307 | }; | |
308 | ||
69f698ad PZ |
309 | #ifdef CONFIG_TRACING |
310 | #include <linux/ftrace.h> | |
311 | ||
1495cc9d | 312 | static void sysrq_ftrace_dump(int key) |
69f698ad | 313 | { |
cecbca96 | 314 | ftrace_dump(DUMP_ALL); |
69f698ad PZ |
315 | } |
316 | static struct sysrq_key_op sysrq_ftrace_dump_op = { | |
317 | .handler = sysrq_ftrace_dump, | |
afa80ccb | 318 | .help_msg = "dump-ftrace-buffer(z)", |
69f698ad PZ |
319 | .action_msg = "Dump ftrace buffer", |
320 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
321 | }; | |
322 | #else | |
97f5f0cd | 323 | #define sysrq_ftrace_dump_op (*(struct sysrq_key_op *)NULL) |
69f698ad | 324 | #endif |
e59e2ae2 | 325 | |
1495cc9d | 326 | static void sysrq_handle_showmem(int key) |
1da177e4 | 327 | { |
9af744d7 | 328 | show_mem(0, NULL); |
1da177e4 LT |
329 | } |
330 | static struct sysrq_key_op sysrq_showmem_op = { | |
331 | .handler = sysrq_handle_showmem, | |
afa80ccb | 332 | .help_msg = "show-memory-usage(m)", |
1da177e4 LT |
333 | .action_msg = "Show Memory", |
334 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
335 | }; | |
336 | ||
bf36b901 AM |
337 | /* |
338 | * Signal sysrq helper function. Sends a signal to all user processes. | |
339 | */ | |
1da177e4 LT |
340 | static void send_sig_all(int sig) |
341 | { | |
342 | struct task_struct *p; | |
343 | ||
e502babe | 344 | read_lock(&tasklist_lock); |
1da177e4 | 345 | for_each_process(p) { |
d3a532a9 AV |
346 | if (p->flags & PF_KTHREAD) |
347 | continue; | |
348 | if (is_global_init(p)) | |
349 | continue; | |
350 | ||
b16503ba | 351 | do_send_sig_info(sig, SEND_SIG_PRIV, p, PIDTYPE_MAX); |
1da177e4 | 352 | } |
e502babe | 353 | read_unlock(&tasklist_lock); |
1da177e4 LT |
354 | } |
355 | ||
1495cc9d | 356 | static void sysrq_handle_term(int key) |
1da177e4 LT |
357 | { |
358 | send_sig_all(SIGTERM); | |
a8fe19eb | 359 | console_loglevel = CONSOLE_LOGLEVEL_DEBUG; |
1da177e4 LT |
360 | } |
361 | static struct sysrq_key_op sysrq_term_op = { | |
362 | .handler = sysrq_handle_term, | |
afa80ccb | 363 | .help_msg = "terminate-all-tasks(e)", |
1da177e4 LT |
364 | .action_msg = "Terminate All Tasks", |
365 | .enable_mask = SYSRQ_ENABLE_SIGNAL, | |
366 | }; | |
367 | ||
65f27f38 | 368 | static void moom_callback(struct work_struct *ignored) |
1da177e4 | 369 | { |
6e0fc46d DR |
370 | const gfp_t gfp_mask = GFP_KERNEL; |
371 | struct oom_control oc = { | |
372 | .zonelist = node_zonelist(first_memory_node, gfp_mask), | |
373 | .nodemask = NULL, | |
2a966b77 | 374 | .memcg = NULL, |
6e0fc46d | 375 | .gfp_mask = gfp_mask, |
54e9e291 | 376 | .order = -1, |
6e0fc46d DR |
377 | }; |
378 | ||
dc56401f | 379 | mutex_lock(&oom_lock); |
6e0fc46d | 380 | if (!out_of_memory(&oc)) |
d75da004 | 381 | pr_info("OOM request ignored. No task eligible\n"); |
dc56401f | 382 | mutex_unlock(&oom_lock); |
1da177e4 LT |
383 | } |
384 | ||
65f27f38 | 385 | static DECLARE_WORK(moom_work, moom_callback); |
1da177e4 | 386 | |
1495cc9d | 387 | static void sysrq_handle_moom(int key) |
1da177e4 LT |
388 | { |
389 | schedule_work(&moom_work); | |
390 | } | |
391 | static struct sysrq_key_op sysrq_moom_op = { | |
392 | .handler = sysrq_handle_moom, | |
afa80ccb | 393 | .help_msg = "memory-full-oom-kill(f)", |
1da177e4 | 394 | .action_msg = "Manual OOM execution", |
b4236f81 | 395 | .enable_mask = SYSRQ_ENABLE_SIGNAL, |
1da177e4 LT |
396 | }; |
397 | ||
c2d75438 | 398 | #ifdef CONFIG_BLOCK |
1495cc9d | 399 | static void sysrq_handle_thaw(int key) |
c2d75438 ES |
400 | { |
401 | emergency_thaw_all(); | |
402 | } | |
403 | static struct sysrq_key_op sysrq_thaw_op = { | |
404 | .handler = sysrq_handle_thaw, | |
afa80ccb | 405 | .help_msg = "thaw-filesystems(j)", |
c2d75438 ES |
406 | .action_msg = "Emergency Thaw of all frozen filesystems", |
407 | .enable_mask = SYSRQ_ENABLE_SIGNAL, | |
408 | }; | |
409 | #endif | |
410 | ||
1495cc9d | 411 | static void sysrq_handle_kill(int key) |
1da177e4 LT |
412 | { |
413 | send_sig_all(SIGKILL); | |
a8fe19eb | 414 | console_loglevel = CONSOLE_LOGLEVEL_DEBUG; |
1da177e4 LT |
415 | } |
416 | static struct sysrq_key_op sysrq_kill_op = { | |
417 | .handler = sysrq_handle_kill, | |
afa80ccb | 418 | .help_msg = "kill-all-tasks(i)", |
1da177e4 LT |
419 | .action_msg = "Kill All Tasks", |
420 | .enable_mask = SYSRQ_ENABLE_SIGNAL, | |
421 | }; | |
422 | ||
1495cc9d | 423 | static void sysrq_handle_unrt(int key) |
1da177e4 LT |
424 | { |
425 | normalize_rt_tasks(); | |
426 | } | |
427 | static struct sysrq_key_op sysrq_unrt_op = { | |
428 | .handler = sysrq_handle_unrt, | |
afa80ccb | 429 | .help_msg = "nice-all-RT-tasks(n)", |
1da177e4 LT |
430 | .action_msg = "Nice All RT Tasks", |
431 | .enable_mask = SYSRQ_ENABLE_RTNICE, | |
432 | }; | |
433 | ||
434 | /* Key Operations table and lock */ | |
435 | static DEFINE_SPINLOCK(sysrq_key_table_lock); | |
bf36b901 AM |
436 | |
437 | static struct sysrq_key_op *sysrq_key_table[36] = { | |
438 | &sysrq_loglevel_op, /* 0 */ | |
439 | &sysrq_loglevel_op, /* 1 */ | |
440 | &sysrq_loglevel_op, /* 2 */ | |
441 | &sysrq_loglevel_op, /* 3 */ | |
442 | &sysrq_loglevel_op, /* 4 */ | |
443 | &sysrq_loglevel_op, /* 5 */ | |
444 | &sysrq_loglevel_op, /* 6 */ | |
445 | &sysrq_loglevel_op, /* 7 */ | |
446 | &sysrq_loglevel_op, /* 8 */ | |
447 | &sysrq_loglevel_op, /* 9 */ | |
448 | ||
449 | /* | |
d346cce3 RD |
450 | * a: Don't use for system provided sysrqs, it is handled specially on |
451 | * sparc and will never arrive. | |
bf36b901 AM |
452 | */ |
453 | NULL, /* a */ | |
454 | &sysrq_reboot_op, /* b */ | |
5e351410 | 455 | &sysrq_crash_op, /* c */ |
bf36b901 AM |
456 | &sysrq_showlocks_op, /* d */ |
457 | &sysrq_term_op, /* e */ | |
458 | &sysrq_moom_op, /* f */ | |
364b5b7b | 459 | /* g: May be registered for the kernel debugger */ |
bf36b901 | 460 | NULL, /* g */ |
c2d75438 | 461 | NULL, /* h - reserved for help */ |
bf36b901 | 462 | &sysrq_kill_op, /* i */ |
c2d75438 ES |
463 | #ifdef CONFIG_BLOCK |
464 | &sysrq_thaw_op, /* j */ | |
465 | #else | |
bf36b901 | 466 | NULL, /* j */ |
c2d75438 | 467 | #endif |
bf36b901 | 468 | &sysrq_SAK_op, /* k */ |
5045bcae RR |
469 | #ifdef CONFIG_SMP |
470 | &sysrq_showallcpus_op, /* l */ | |
471 | #else | |
bf36b901 | 472 | NULL, /* l */ |
5045bcae | 473 | #endif |
bf36b901 AM |
474 | &sysrq_showmem_op, /* m */ |
475 | &sysrq_unrt_op, /* n */ | |
d346cce3 | 476 | /* o: This will often be registered as 'Off' at init time */ |
bf36b901 AM |
477 | NULL, /* o */ |
478 | &sysrq_showregs_op, /* p */ | |
88ad0bf6 | 479 | &sysrq_show_timers_op, /* q */ |
d346cce3 | 480 | &sysrq_unraw_op, /* r */ |
bf36b901 AM |
481 | &sysrq_sync_op, /* s */ |
482 | &sysrq_showstate_op, /* t */ | |
483 | &sysrq_mountro_op, /* u */ | |
364b5b7b | 484 | /* v: May be registered for frame buffer console restore */ |
bf36b901 | 485 | NULL, /* v */ |
d346cce3 | 486 | &sysrq_showstate_blocked_op, /* w */ |
d1e9a4f5 | 487 | /* x: May be registered on mips for TLB dump */ |
d346cce3 | 488 | /* x: May be registered on ppc/powerpc for xmon */ |
916ca14a | 489 | /* x: May be registered on sparc64 for global PMU dump */ |
d346cce3 | 490 | NULL, /* x */ |
93dae5b7 | 491 | /* y: May be registered on sparc64 for global register dump */ |
bf36b901 | 492 | NULL, /* y */ |
69f698ad | 493 | &sysrq_ftrace_dump_op, /* z */ |
1da177e4 LT |
494 | }; |
495 | ||
496 | /* key2index calculation, -1 on invalid index */ | |
bf36b901 AM |
497 | static int sysrq_key_table_key2index(int key) |
498 | { | |
1da177e4 | 499 | int retval; |
bf36b901 AM |
500 | |
501 | if ((key >= '0') && (key <= '9')) | |
1da177e4 | 502 | retval = key - '0'; |
bf36b901 | 503 | else if ((key >= 'a') && (key <= 'z')) |
1da177e4 | 504 | retval = key + 10 - 'a'; |
bf36b901 | 505 | else |
1da177e4 | 506 | retval = -1; |
1da177e4 LT |
507 | return retval; |
508 | } | |
509 | ||
510 | /* | |
511 | * get and put functions for the table, exposed to modules. | |
512 | */ | |
bf36b901 AM |
513 | struct sysrq_key_op *__sysrq_get_key_op(int key) |
514 | { | |
515 | struct sysrq_key_op *op_p = NULL; | |
1da177e4 | 516 | int i; |
bf36b901 | 517 | |
1da177e4 | 518 | i = sysrq_key_table_key2index(key); |
bf36b901 AM |
519 | if (i != -1) |
520 | op_p = sysrq_key_table[i]; | |
97f5f0cd | 521 | |
1da177e4 LT |
522 | return op_p; |
523 | } | |
524 | ||
bf36b901 AM |
525 | static void __sysrq_put_key_op(int key, struct sysrq_key_op *op_p) |
526 | { | |
527 | int i = sysrq_key_table_key2index(key); | |
1da177e4 | 528 | |
1da177e4 LT |
529 | if (i != -1) |
530 | sysrq_key_table[i] = op_p; | |
531 | } | |
532 | ||
f335397d | 533 | void __handle_sysrq(int key, bool check_mask) |
1da177e4 LT |
534 | { |
535 | struct sysrq_key_op *op_p; | |
536 | int orig_log_level; | |
bf36b901 | 537 | int i; |
1da177e4 | 538 | |
722773af | 539 | rcu_sysrq_start(); |
984d74a7 | 540 | rcu_read_lock(); |
fb144adc AW |
541 | /* |
542 | * Raise the apparent loglevel to maximum so that the sysrq header | |
543 | * is shown to provide the user with positive feedback. We do not | |
544 | * simply emit this at KERN_EMERG as that would change message | |
545 | * routing in the consumers of /proc/kmsg. | |
546 | */ | |
1da177e4 | 547 | orig_log_level = console_loglevel; |
a8fe19eb | 548 | console_loglevel = CONSOLE_LOGLEVEL_DEFAULT; |
401e4a7c | 549 | pr_info("SysRq : "); |
1da177e4 LT |
550 | |
551 | op_p = __sysrq_get_key_op(key); | |
552 | if (op_p) { | |
bf36b901 AM |
553 | /* |
554 | * Should we check for enabled operations (/proc/sysrq-trigger | |
555 | * should not) and is the invoked operation enabled? | |
556 | */ | |
5d6f647f | 557 | if (!check_mask || sysrq_on_mask(op_p->enable_mask)) { |
401e4a7c | 558 | pr_cont("%s\n", op_p->action_msg); |
1da177e4 | 559 | console_loglevel = orig_log_level; |
1495cc9d | 560 | op_p->handler(key); |
bf36b901 | 561 | } else { |
401e4a7c | 562 | pr_cont("This sysrq operation is disabled.\n"); |
bf36b901 | 563 | } |
1da177e4 | 564 | } else { |
401e4a7c | 565 | pr_cont("HELP : "); |
1da177e4 | 566 | /* Only print the help msg once per handler */ |
bf36b901 AM |
567 | for (i = 0; i < ARRAY_SIZE(sysrq_key_table); i++) { |
568 | if (sysrq_key_table[i]) { | |
569 | int j; | |
570 | ||
571 | for (j = 0; sysrq_key_table[i] != | |
572 | sysrq_key_table[j]; j++) | |
573 | ; | |
574 | if (j != i) | |
575 | continue; | |
401e4a7c | 576 | pr_cont("%s ", sysrq_key_table[i]->help_msg); |
bf36b901 | 577 | } |
1da177e4 | 578 | } |
401e4a7c | 579 | pr_cont("\n"); |
1da177e4 LT |
580 | console_loglevel = orig_log_level; |
581 | } | |
984d74a7 | 582 | rcu_read_unlock(); |
722773af | 583 | rcu_sysrq_end(); |
1da177e4 LT |
584 | } |
585 | ||
f335397d | 586 | void handle_sysrq(int key) |
1da177e4 | 587 | { |
5d6f647f | 588 | if (sysrq_on()) |
f335397d | 589 | __handle_sysrq(key, true); |
1da177e4 | 590 | } |
bf36b901 | 591 | EXPORT_SYMBOL(handle_sysrq); |
1da177e4 | 592 | |
97f5f0cd | 593 | #ifdef CONFIG_INPUT |
ffb6e0c9 | 594 | static int sysrq_reset_downtime_ms; |
97f5f0cd DT |
595 | |
596 | /* Simple translation table for the SysRq keys */ | |
fcb71930 | 597 | static const unsigned char sysrq_xlate[KEY_CNT] = |
97f5f0cd DT |
598 | "\000\0331234567890-=\177\t" /* 0x00 - 0x0f */ |
599 | "qwertyuiop[]\r\000as" /* 0x10 - 0x1f */ | |
600 | "dfghjkl;'`\000\\zxcv" /* 0x20 - 0x2f */ | |
601 | "bnm,./\000*\000 \000\201\202\203\204\205" /* 0x30 - 0x3f */ | |
602 | "\206\207\210\211\212\000\000789-456+1" /* 0x40 - 0x4f */ | |
603 | "230\177\000\000\213\214\000\000\000\000\000\000\000\000\000\000" /* 0x50 - 0x5f */ | |
604 | "\r\000/"; /* 0x60 - 0x6f */ | |
605 | ||
fcb71930 DT |
606 | struct sysrq_state { |
607 | struct input_handle handle; | |
608 | struct work_struct reinject_work; | |
609 | unsigned long key_down[BITS_TO_LONGS(KEY_CNT)]; | |
610 | unsigned int alt; | |
611 | unsigned int alt_use; | |
612 | bool active; | |
613 | bool need_reinject; | |
7ab7b5ad | 614 | bool reinjecting; |
154b7a48 MP |
615 | |
616 | /* reset sequence handling */ | |
617 | bool reset_canceled; | |
3d289517 | 618 | bool reset_requested; |
154b7a48 MP |
619 | unsigned long reset_keybit[BITS_TO_LONGS(KEY_CNT)]; |
620 | int reset_seq_len; | |
621 | int reset_seq_cnt; | |
622 | int reset_seq_version; | |
39030786 | 623 | struct timer_list keyreset_timer; |
fcb71930 DT |
624 | }; |
625 | ||
154b7a48 MP |
626 | #define SYSRQ_KEY_RESET_MAX 20 /* Should be plenty */ |
627 | static unsigned short sysrq_reset_seq[SYSRQ_KEY_RESET_MAX]; | |
628 | static unsigned int sysrq_reset_seq_len; | |
629 | static unsigned int sysrq_reset_seq_version = 1; | |
630 | ||
631 | static void sysrq_parse_reset_sequence(struct sysrq_state *state) | |
632 | { | |
633 | int i; | |
634 | unsigned short key; | |
635 | ||
636 | state->reset_seq_cnt = 0; | |
637 | ||
638 | for (i = 0; i < sysrq_reset_seq_len; i++) { | |
639 | key = sysrq_reset_seq[i]; | |
640 | ||
641 | if (key == KEY_RESERVED || key > KEY_MAX) | |
642 | break; | |
643 | ||
644 | __set_bit(key, state->reset_keybit); | |
645 | state->reset_seq_len++; | |
646 | ||
647 | if (test_bit(key, state->key_down)) | |
648 | state->reset_seq_cnt++; | |
649 | } | |
650 | ||
651 | /* Disable reset until old keys are not released */ | |
652 | state->reset_canceled = state->reset_seq_cnt != 0; | |
653 | ||
654 | state->reset_seq_version = sysrq_reset_seq_version; | |
655 | } | |
656 | ||
8c318fa9 | 657 | static void sysrq_do_reset(struct timer_list *t) |
39030786 | 658 | { |
8c318fa9 | 659 | struct sysrq_state *state = from_timer(state, t, keyreset_timer); |
3d289517 MP |
660 | |
661 | state->reset_requested = true; | |
662 | ||
70f68ee8 | 663 | ksys_sync(); |
3d289517 | 664 | kernel_restart(NULL); |
39030786 MP |
665 | } |
666 | ||
667 | static void sysrq_handle_reset_request(struct sysrq_state *state) | |
668 | { | |
3d289517 MP |
669 | if (state->reset_requested) |
670 | __handle_sysrq(sysrq_xlate[KEY_B], false); | |
671 | ||
39030786 MP |
672 | if (sysrq_reset_downtime_ms) |
673 | mod_timer(&state->keyreset_timer, | |
674 | jiffies + msecs_to_jiffies(sysrq_reset_downtime_ms)); | |
675 | else | |
8c318fa9 | 676 | sysrq_do_reset(&state->keyreset_timer); |
39030786 MP |
677 | } |
678 | ||
679 | static void sysrq_detect_reset_sequence(struct sysrq_state *state, | |
154b7a48 MP |
680 | unsigned int code, int value) |
681 | { | |
682 | if (!test_bit(code, state->reset_keybit)) { | |
683 | /* | |
684 | * Pressing any key _not_ in reset sequence cancels | |
39030786 MP |
685 | * the reset sequence. Also cancelling the timer in |
686 | * case additional keys were pressed after a reset | |
687 | * has been requested. | |
154b7a48 | 688 | */ |
39030786 | 689 | if (value && state->reset_seq_cnt) { |
154b7a48 | 690 | state->reset_canceled = true; |
39030786 MP |
691 | del_timer(&state->keyreset_timer); |
692 | } | |
154b7a48 | 693 | } else if (value == 0) { |
39030786 MP |
694 | /* |
695 | * Key release - all keys in the reset sequence need | |
696 | * to be pressed and held for the reset timeout | |
697 | * to hold. | |
698 | */ | |
699 | del_timer(&state->keyreset_timer); | |
700 | ||
154b7a48 MP |
701 | if (--state->reset_seq_cnt == 0) |
702 | state->reset_canceled = false; | |
703 | } else if (value == 1) { | |
704 | /* key press, not autorepeat */ | |
705 | if (++state->reset_seq_cnt == state->reset_seq_len && | |
706 | !state->reset_canceled) { | |
39030786 | 707 | sysrq_handle_reset_request(state); |
154b7a48 MP |
708 | } |
709 | } | |
154b7a48 MP |
710 | } |
711 | ||
4c076eb0 MP |
712 | #ifdef CONFIG_OF |
713 | static void sysrq_of_get_keyreset_config(void) | |
714 | { | |
715 | u32 key; | |
716 | struct device_node *np; | |
717 | struct property *prop; | |
718 | const __be32 *p; | |
719 | ||
720 | np = of_find_node_by_path("/chosen/linux,sysrq-reset-seq"); | |
721 | if (!np) { | |
722 | pr_debug("No sysrq node found"); | |
723 | return; | |
724 | } | |
725 | ||
726 | /* Reset in case a __weak definition was present */ | |
727 | sysrq_reset_seq_len = 0; | |
728 | ||
729 | of_property_for_each_u32(np, "keyset", prop, p, key) { | |
730 | if (key == KEY_RESERVED || key > KEY_MAX || | |
731 | sysrq_reset_seq_len == SYSRQ_KEY_RESET_MAX) | |
732 | break; | |
733 | ||
734 | sysrq_reset_seq[sysrq_reset_seq_len++] = (unsigned short)key; | |
735 | } | |
736 | ||
737 | /* Get reset timeout if any. */ | |
738 | of_property_read_u32(np, "timeout-ms", &sysrq_reset_downtime_ms); | |
739 | } | |
740 | #else | |
741 | static void sysrq_of_get_keyreset_config(void) | |
742 | { | |
743 | } | |
744 | #endif | |
745 | ||
fcb71930 DT |
746 | static void sysrq_reinject_alt_sysrq(struct work_struct *work) |
747 | { | |
748 | struct sysrq_state *sysrq = | |
749 | container_of(work, struct sysrq_state, reinject_work); | |
750 | struct input_handle *handle = &sysrq->handle; | |
751 | unsigned int alt_code = sysrq->alt_use; | |
752 | ||
753 | if (sysrq->need_reinject) { | |
7ab7b5ad DT |
754 | /* we do not want the assignment to be reordered */ |
755 | sysrq->reinjecting = true; | |
756 | mb(); | |
757 | ||
fcb71930 DT |
758 | /* Simulate press and release of Alt + SysRq */ |
759 | input_inject_event(handle, EV_KEY, alt_code, 1); | |
760 | input_inject_event(handle, EV_KEY, KEY_SYSRQ, 1); | |
761 | input_inject_event(handle, EV_SYN, SYN_REPORT, 1); | |
762 | ||
763 | input_inject_event(handle, EV_KEY, KEY_SYSRQ, 0); | |
764 | input_inject_event(handle, EV_KEY, alt_code, 0); | |
765 | input_inject_event(handle, EV_SYN, SYN_REPORT, 1); | |
7ab7b5ad DT |
766 | |
767 | mb(); | |
768 | sysrq->reinjecting = false; | |
fcb71930 DT |
769 | } |
770 | } | |
97f5f0cd | 771 | |
154b7a48 MP |
772 | static bool sysrq_handle_keypress(struct sysrq_state *sysrq, |
773 | unsigned int code, int value) | |
97f5f0cd | 774 | { |
fcb71930 | 775 | bool was_active = sysrq->active; |
1966cb22 DT |
776 | bool suppress; |
777 | ||
154b7a48 | 778 | switch (code) { |
7ab7b5ad | 779 | |
154b7a48 MP |
780 | case KEY_LEFTALT: |
781 | case KEY_RIGHTALT: | |
782 | if (!value) { | |
783 | /* One of ALTs is being released */ | |
784 | if (sysrq->active && code == sysrq->alt_use) | |
785 | sysrq->active = false; | |
1966cb22 | 786 | |
154b7a48 MP |
787 | sysrq->alt = KEY_RESERVED; |
788 | ||
789 | } else if (value != 2) { | |
790 | sysrq->alt = code; | |
791 | sysrq->need_reinject = false; | |
792 | } | |
fcb71930 | 793 | break; |
97f5f0cd | 794 | |
154b7a48 MP |
795 | case KEY_SYSRQ: |
796 | if (value == 1 && sysrq->alt != KEY_RESERVED) { | |
797 | sysrq->active = true; | |
798 | sysrq->alt_use = sysrq->alt; | |
799 | /* | |
800 | * If nothing else will be pressed we'll need | |
801 | * to re-inject Alt-SysRq keysroke. | |
802 | */ | |
803 | sysrq->need_reinject = true; | |
804 | } | |
97f5f0cd | 805 | |
154b7a48 MP |
806 | /* |
807 | * Pretend that sysrq was never pressed at all. This | |
808 | * is needed to properly handle KGDB which will try | |
809 | * to release all keys after exiting debugger. If we | |
810 | * do not clear key bit it KGDB will end up sending | |
811 | * release events for Alt and SysRq, potentially | |
812 | * triggering print screen function. | |
813 | */ | |
814 | if (sysrq->active) | |
815 | clear_bit(KEY_SYSRQ, sysrq->handle.dev->key); | |
f5dec511 | 816 | |
154b7a48 | 817 | break; |
fcb71930 | 818 | |
154b7a48 MP |
819 | default: |
820 | if (sysrq->active && value && value != 2) { | |
821 | sysrq->need_reinject = false; | |
822 | __handle_sysrq(sysrq_xlate[code], true); | |
823 | } | |
824 | break; | |
825 | } | |
fcb71930 | 826 | |
154b7a48 | 827 | suppress = sysrq->active; |
fcb71930 | 828 | |
154b7a48 | 829 | if (!sysrq->active) { |
fcb71930 | 830 | |
154b7a48 MP |
831 | /* |
832 | * See if reset sequence has changed since the last time. | |
833 | */ | |
834 | if (sysrq->reset_seq_version != sysrq_reset_seq_version) | |
835 | sysrq_parse_reset_sequence(sysrq); | |
fcb71930 | 836 | |
154b7a48 MP |
837 | /* |
838 | * If we are not suppressing key presses keep track of | |
839 | * keyboard state so we can release keys that have been | |
840 | * pressed before entering SysRq mode. | |
841 | */ | |
842 | if (value) | |
843 | set_bit(code, sysrq->key_down); | |
844 | else | |
845 | clear_bit(code, sysrq->key_down); | |
846 | ||
847 | if (was_active) | |
848 | schedule_work(&sysrq->reinject_work); | |
849 | ||
39030786 MP |
850 | /* Check for reset sequence */ |
851 | sysrq_detect_reset_sequence(sysrq, code, value); | |
97f5f0cd | 852 | |
154b7a48 MP |
853 | } else if (value == 0 && test_and_clear_bit(code, sysrq->key_down)) { |
854 | /* | |
855 | * Pass on release events for keys that was pressed before | |
856 | * entering SysRq mode. | |
857 | */ | |
858 | suppress = false; | |
859 | } | |
fcb71930 | 860 | |
154b7a48 MP |
861 | return suppress; |
862 | } | |
fcb71930 | 863 | |
154b7a48 MP |
864 | static bool sysrq_filter(struct input_handle *handle, |
865 | unsigned int type, unsigned int code, int value) | |
866 | { | |
867 | struct sysrq_state *sysrq = handle->private; | |
868 | bool suppress; | |
fcb71930 | 869 | |
154b7a48 MP |
870 | /* |
871 | * Do not filter anything if we are in the process of re-injecting | |
872 | * Alt+SysRq combination. | |
873 | */ | |
874 | if (sysrq->reinjecting) | |
875 | return false; | |
876 | ||
877 | switch (type) { | |
878 | ||
879 | case EV_SYN: | |
880 | suppress = false; | |
881 | break; | |
882 | ||
883 | case EV_KEY: | |
884 | suppress = sysrq_handle_keypress(sysrq, code, value); | |
97f5f0cd DT |
885 | break; |
886 | ||
887 | default: | |
fcb71930 | 888 | suppress = sysrq->active; |
97f5f0cd DT |
889 | break; |
890 | } | |
891 | ||
1966cb22 | 892 | return suppress; |
97f5f0cd DT |
893 | } |
894 | ||
895 | static int sysrq_connect(struct input_handler *handler, | |
896 | struct input_dev *dev, | |
897 | const struct input_device_id *id) | |
898 | { | |
fcb71930 | 899 | struct sysrq_state *sysrq; |
97f5f0cd DT |
900 | int error; |
901 | ||
fcb71930 DT |
902 | sysrq = kzalloc(sizeof(struct sysrq_state), GFP_KERNEL); |
903 | if (!sysrq) | |
97f5f0cd DT |
904 | return -ENOMEM; |
905 | ||
fcb71930 DT |
906 | INIT_WORK(&sysrq->reinject_work, sysrq_reinject_alt_sysrq); |
907 | ||
908 | sysrq->handle.dev = dev; | |
909 | sysrq->handle.handler = handler; | |
910 | sysrq->handle.name = "sysrq"; | |
911 | sysrq->handle.private = sysrq; | |
8c318fa9 | 912 | timer_setup(&sysrq->keyreset_timer, sysrq_do_reset, 0); |
97f5f0cd | 913 | |
fcb71930 | 914 | error = input_register_handle(&sysrq->handle); |
97f5f0cd DT |
915 | if (error) { |
916 | pr_err("Failed to register input sysrq handler, error %d\n", | |
917 | error); | |
918 | goto err_free; | |
919 | } | |
920 | ||
fcb71930 | 921 | error = input_open_device(&sysrq->handle); |
97f5f0cd DT |
922 | if (error) { |
923 | pr_err("Failed to open input device, error %d\n", error); | |
924 | goto err_unregister; | |
925 | } | |
926 | ||
927 | return 0; | |
928 | ||
929 | err_unregister: | |
fcb71930 | 930 | input_unregister_handle(&sysrq->handle); |
97f5f0cd | 931 | err_free: |
fcb71930 | 932 | kfree(sysrq); |
97f5f0cd DT |
933 | return error; |
934 | } | |
935 | ||
936 | static void sysrq_disconnect(struct input_handle *handle) | |
937 | { | |
fcb71930 DT |
938 | struct sysrq_state *sysrq = handle->private; |
939 | ||
97f5f0cd | 940 | input_close_device(handle); |
fcb71930 | 941 | cancel_work_sync(&sysrq->reinject_work); |
39030786 | 942 | del_timer_sync(&sysrq->keyreset_timer); |
97f5f0cd | 943 | input_unregister_handle(handle); |
fcb71930 | 944 | kfree(sysrq); |
97f5f0cd DT |
945 | } |
946 | ||
947 | /* | |
1966cb22 DT |
948 | * We are matching on KEY_LEFTALT instead of KEY_SYSRQ because not all |
949 | * keyboards have SysRq key predefined and so user may add it to keymap | |
97f5f0cd DT |
950 | * later, but we expect all such keyboards to have left alt. |
951 | */ | |
952 | static const struct input_device_id sysrq_ids[] = { | |
953 | { | |
954 | .flags = INPUT_DEVICE_ID_MATCH_EVBIT | | |
955 | INPUT_DEVICE_ID_MATCH_KEYBIT, | |
802c0388 AM |
956 | .evbit = { [BIT_WORD(EV_KEY)] = BIT_MASK(EV_KEY) }, |
957 | .keybit = { [BIT_WORD(KEY_LEFTALT)] = BIT_MASK(KEY_LEFTALT) }, | |
97f5f0cd DT |
958 | }, |
959 | { }, | |
960 | }; | |
961 | ||
962 | static struct input_handler sysrq_handler = { | |
963 | .filter = sysrq_filter, | |
964 | .connect = sysrq_connect, | |
965 | .disconnect = sysrq_disconnect, | |
966 | .name = "sysrq", | |
967 | .id_table = sysrq_ids, | |
968 | }; | |
969 | ||
970 | static bool sysrq_handler_registered; | |
971 | ||
972 | static inline void sysrq_register_handler(void) | |
973 | { | |
974 | int error; | |
975 | ||
4c076eb0 MP |
976 | sysrq_of_get_keyreset_config(); |
977 | ||
97f5f0cd DT |
978 | error = input_register_handler(&sysrq_handler); |
979 | if (error) | |
980 | pr_err("Failed to register input handler, error %d", error); | |
981 | else | |
982 | sysrq_handler_registered = true; | |
983 | } | |
984 | ||
985 | static inline void sysrq_unregister_handler(void) | |
986 | { | |
987 | if (sysrq_handler_registered) { | |
988 | input_unregister_handler(&sysrq_handler); | |
989 | sysrq_handler_registered = false; | |
990 | } | |
991 | } | |
992 | ||
154b7a48 MP |
993 | static int sysrq_reset_seq_param_set(const char *buffer, |
994 | const struct kernel_param *kp) | |
995 | { | |
996 | unsigned long val; | |
997 | int error; | |
998 | ||
86b40567 | 999 | error = kstrtoul(buffer, 0, &val); |
154b7a48 MP |
1000 | if (error < 0) |
1001 | return error; | |
1002 | ||
1003 | if (val > KEY_MAX) | |
1004 | return -EINVAL; | |
1005 | ||
1006 | *((unsigned short *)kp->arg) = val; | |
1007 | sysrq_reset_seq_version++; | |
1008 | ||
1009 | return 0; | |
1010 | } | |
1011 | ||
9c27847d | 1012 | static const struct kernel_param_ops param_ops_sysrq_reset_seq = { |
154b7a48 MP |
1013 | .get = param_get_ushort, |
1014 | .set = sysrq_reset_seq_param_set, | |
1015 | }; | |
1016 | ||
1017 | #define param_check_sysrq_reset_seq(name, p) \ | |
1018 | __param_check(name, p, unsigned short) | |
1019 | ||
3bce6f64 PG |
1020 | /* |
1021 | * not really modular, but the easiest way to keep compat with existing | |
1022 | * bootargs behaviour is to continue using module_param here. | |
1023 | */ | |
154b7a48 MP |
1024 | module_param_array_named(reset_seq, sysrq_reset_seq, sysrq_reset_seq, |
1025 | &sysrq_reset_seq_len, 0644); | |
1026 | ||
39030786 MP |
1027 | module_param_named(sysrq_downtime_ms, sysrq_reset_downtime_ms, int, 0644); |
1028 | ||
97f5f0cd DT |
1029 | #else |
1030 | ||
1031 | static inline void sysrq_register_handler(void) | |
1032 | { | |
1033 | } | |
1034 | ||
1035 | static inline void sysrq_unregister_handler(void) | |
1036 | { | |
1037 | } | |
1038 | ||
1039 | #endif /* CONFIG_INPUT */ | |
1040 | ||
1041 | int sysrq_toggle_support(int enable_mask) | |
1042 | { | |
1043 | bool was_enabled = sysrq_on(); | |
1044 | ||
1045 | sysrq_enabled = enable_mask; | |
1046 | ||
1047 | if (was_enabled != sysrq_on()) { | |
1048 | if (sysrq_on()) | |
1049 | sysrq_register_handler(); | |
1050 | else | |
1051 | sysrq_unregister_handler(); | |
1052 | } | |
1053 | ||
1054 | return 0; | |
1055 | } | |
1056 | ||
cf62ddce | 1057 | static int __sysrq_swap_key_ops(int key, struct sysrq_key_op *insert_op_p, |
bf36b901 AM |
1058 | struct sysrq_key_op *remove_op_p) |
1059 | { | |
1da177e4 | 1060 | int retval; |
1da177e4 | 1061 | |
984d74a7 | 1062 | spin_lock(&sysrq_key_table_lock); |
1da177e4 LT |
1063 | if (__sysrq_get_key_op(key) == remove_op_p) { |
1064 | __sysrq_put_key_op(key, insert_op_p); | |
1065 | retval = 0; | |
1066 | } else { | |
1067 | retval = -1; | |
1068 | } | |
984d74a7 RR |
1069 | spin_unlock(&sysrq_key_table_lock); |
1070 | ||
1071 | /* | |
1072 | * A concurrent __handle_sysrq either got the old op or the new op. | |
1073 | * Wait for it to go away before returning, so the code for an old | |
1074 | * op is not freed (eg. on module unload) while it is in use. | |
1075 | */ | |
1076 | synchronize_rcu(); | |
1077 | ||
1da177e4 LT |
1078 | return retval; |
1079 | } | |
1080 | ||
1081 | int register_sysrq_key(int key, struct sysrq_key_op *op_p) | |
1082 | { | |
1083 | return __sysrq_swap_key_ops(key, op_p, NULL); | |
1084 | } | |
bf36b901 | 1085 | EXPORT_SYMBOL(register_sysrq_key); |
1da177e4 LT |
1086 | |
1087 | int unregister_sysrq_key(int key, struct sysrq_key_op *op_p) | |
1088 | { | |
1089 | return __sysrq_swap_key_ops(key, NULL, op_p); | |
1090 | } | |
1da177e4 | 1091 | EXPORT_SYMBOL(unregister_sysrq_key); |
f40cbaa5 AD |
1092 | |
1093 | #ifdef CONFIG_PROC_FS | |
1094 | /* | |
1095 | * writing 'C' to /proc/sysrq-trigger is like sysrq-C | |
1096 | */ | |
1097 | static ssize_t write_sysrq_trigger(struct file *file, const char __user *buf, | |
1098 | size_t count, loff_t *ppos) | |
1099 | { | |
1100 | if (count) { | |
1101 | char c; | |
1102 | ||
1103 | if (get_user(c, buf)) | |
1104 | return -EFAULT; | |
f335397d | 1105 | __handle_sysrq(c, false); |
f40cbaa5 | 1106 | } |
97f5f0cd | 1107 | |
f40cbaa5 AD |
1108 | return count; |
1109 | } | |
1110 | ||
1111 | static const struct file_operations proc_sysrq_trigger_operations = { | |
1112 | .write = write_sysrq_trigger, | |
6038f373 | 1113 | .llseek = noop_llseek, |
f40cbaa5 AD |
1114 | }; |
1115 | ||
97f5f0cd DT |
1116 | static void sysrq_init_procfs(void) |
1117 | { | |
1118 | if (!proc_create("sysrq-trigger", S_IWUSR, NULL, | |
1119 | &proc_sysrq_trigger_operations)) | |
1120 | pr_err("Failed to register proc interface\n"); | |
1121 | } | |
1122 | ||
1123 | #else | |
1124 | ||
1125 | static inline void sysrq_init_procfs(void) | |
1126 | { | |
1127 | } | |
1128 | ||
1129 | #endif /* CONFIG_PROC_FS */ | |
1130 | ||
f40cbaa5 AD |
1131 | static int __init sysrq_init(void) |
1132 | { | |
97f5f0cd DT |
1133 | sysrq_init_procfs(); |
1134 | ||
1135 | if (sysrq_on()) | |
1136 | sysrq_register_handler(); | |
1137 | ||
f40cbaa5 AD |
1138 | return 0; |
1139 | } | |
3bce6f64 | 1140 | device_initcall(sysrq_init); |