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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 | { |
8341f2f2 | 137 | /* release the RCU read lock before crashing */ |
984cf355 | 138 | rcu_read_unlock(); |
8341f2f2 MK |
139 | |
140 | panic("sysrq triggered crash\n"); | |
86b1ae38 | 141 | } |
cab8bd34 | 142 | static struct sysrq_key_op sysrq_crash_op = { |
d6580a9f | 143 | .handler = sysrq_handle_crash, |
afa80ccb | 144 | .help_msg = "crash(c)", |
d6580a9f | 145 | .action_msg = "Trigger a crash", |
86b1ae38 HN |
146 | .enable_mask = SYSRQ_ENABLE_DUMP, |
147 | }; | |
86b1ae38 | 148 | |
1495cc9d | 149 | static void sysrq_handle_reboot(int key) |
1da177e4 | 150 | { |
b2e9c7d0 | 151 | lockdep_off(); |
1da177e4 | 152 | local_irq_enable(); |
4de8b9b7 | 153 | emergency_restart(); |
1da177e4 | 154 | } |
1da177e4 LT |
155 | static struct sysrq_key_op sysrq_reboot_op = { |
156 | .handler = sysrq_handle_reboot, | |
afa80ccb | 157 | .help_msg = "reboot(b)", |
1da177e4 LT |
158 | .action_msg = "Resetting", |
159 | .enable_mask = SYSRQ_ENABLE_BOOT, | |
160 | }; | |
161 | ||
1495cc9d | 162 | static void sysrq_handle_sync(int key) |
1da177e4 LT |
163 | { |
164 | emergency_sync(); | |
165 | } | |
1da177e4 LT |
166 | static struct sysrq_key_op sysrq_sync_op = { |
167 | .handler = sysrq_handle_sync, | |
afa80ccb | 168 | .help_msg = "sync(s)", |
1da177e4 LT |
169 | .action_msg = "Emergency Sync", |
170 | .enable_mask = SYSRQ_ENABLE_SYNC, | |
171 | }; | |
172 | ||
1495cc9d | 173 | static void sysrq_handle_show_timers(int key) |
88ad0bf6 IM |
174 | { |
175 | sysrq_timer_list_show(); | |
176 | } | |
177 | ||
178 | static struct sysrq_key_op sysrq_show_timers_op = { | |
179 | .handler = sysrq_handle_show_timers, | |
afa80ccb | 180 | .help_msg = "show-all-timers(q)", |
322acf65 | 181 | .action_msg = "Show clockevent devices & pending hrtimers (no others)", |
88ad0bf6 IM |
182 | }; |
183 | ||
1495cc9d | 184 | static void sysrq_handle_mountro(int key) |
1da177e4 LT |
185 | { |
186 | emergency_remount(); | |
187 | } | |
1da177e4 LT |
188 | static struct sysrq_key_op sysrq_mountro_op = { |
189 | .handler = sysrq_handle_mountro, | |
afa80ccb | 190 | .help_msg = "unmount(u)", |
1da177e4 LT |
191 | .action_msg = "Emergency Remount R/O", |
192 | .enable_mask = SYSRQ_ENABLE_REMOUNT, | |
193 | }; | |
194 | ||
8c64580d | 195 | #ifdef CONFIG_LOCKDEP |
1495cc9d | 196 | static void sysrq_handle_showlocks(int key) |
de5097c2 | 197 | { |
9a11b49a | 198 | debug_show_all_locks(); |
de5097c2 | 199 | } |
8c64580d | 200 | |
de5097c2 IM |
201 | static struct sysrq_key_op sysrq_showlocks_op = { |
202 | .handler = sysrq_handle_showlocks, | |
afa80ccb | 203 | .help_msg = "show-all-locks(d)", |
de5097c2 IM |
204 | .action_msg = "Show Locks Held", |
205 | }; | |
bf36b901 | 206 | #else |
97f5f0cd | 207 | #define sysrq_showlocks_op (*(struct sysrq_key_op *)NULL) |
de5097c2 | 208 | #endif |
1da177e4 | 209 | |
5045bcae | 210 | #ifdef CONFIG_SMP |
6ac972dd | 211 | static DEFINE_RAW_SPINLOCK(show_lock); |
5045bcae RR |
212 | |
213 | static void showacpu(void *dummy) | |
214 | { | |
215 | unsigned long flags; | |
216 | ||
217 | /* Idle CPUs have no interesting backtrace. */ | |
218 | if (idle_cpu(smp_processor_id())) | |
219 | return; | |
220 | ||
6ac972dd | 221 | raw_spin_lock_irqsave(&show_lock, flags); |
401e4a7c | 222 | pr_info("CPU%d:\n", smp_processor_id()); |
5045bcae | 223 | show_stack(NULL, NULL); |
6ac972dd | 224 | raw_spin_unlock_irqrestore(&show_lock, flags); |
5045bcae RR |
225 | } |
226 | ||
227 | static void sysrq_showregs_othercpus(struct work_struct *dummy) | |
228 | { | |
8b604d52 | 229 | smp_call_function(showacpu, NULL, 0); |
5045bcae RR |
230 | } |
231 | ||
232 | static DECLARE_WORK(sysrq_showallcpus, sysrq_showregs_othercpus); | |
233 | ||
1495cc9d | 234 | static void sysrq_handle_showallcpus(int key) |
5045bcae | 235 | { |
47cab6a7 IM |
236 | /* |
237 | * Fall back to the workqueue based printing if the | |
238 | * backtrace printing did not succeed or the | |
239 | * architecture has no support for it: | |
240 | */ | |
241 | if (!trigger_all_cpu_backtrace()) { | |
b00bebbc | 242 | struct pt_regs *regs = NULL; |
47cab6a7 | 243 | |
b00bebbc JX |
244 | if (in_irq()) |
245 | regs = get_irq_regs(); | |
47cab6a7 | 246 | if (regs) { |
401e4a7c | 247 | pr_info("CPU%d:\n", smp_processor_id()); |
47cab6a7 IM |
248 | show_regs(regs); |
249 | } | |
250 | schedule_work(&sysrq_showallcpus); | |
251 | } | |
5045bcae RR |
252 | } |
253 | ||
254 | static struct sysrq_key_op sysrq_showallcpus_op = { | |
255 | .handler = sysrq_handle_showallcpus, | |
afa80ccb | 256 | .help_msg = "show-backtrace-all-active-cpus(l)", |
5045bcae RR |
257 | .action_msg = "Show backtrace of all active CPUs", |
258 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
259 | }; | |
260 | #endif | |
261 | ||
1495cc9d | 262 | static void sysrq_handle_showregs(int key) |
1da177e4 | 263 | { |
b00bebbc JX |
264 | struct pt_regs *regs = NULL; |
265 | ||
266 | if (in_irq()) | |
267 | regs = get_irq_regs(); | |
7d12e780 DH |
268 | if (regs) |
269 | show_regs(regs); | |
cdd6c482 | 270 | perf_event_print_debug(); |
1da177e4 LT |
271 | } |
272 | static struct sysrq_key_op sysrq_showregs_op = { | |
273 | .handler = sysrq_handle_showregs, | |
afa80ccb | 274 | .help_msg = "show-registers(p)", |
1da177e4 LT |
275 | .action_msg = "Show Regs", |
276 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
277 | }; | |
278 | ||
1495cc9d | 279 | static void sysrq_handle_showstate(int key) |
1da177e4 LT |
280 | { |
281 | show_state(); | |
3494fc30 | 282 | show_workqueue_state(); |
1da177e4 LT |
283 | } |
284 | static struct sysrq_key_op sysrq_showstate_op = { | |
285 | .handler = sysrq_handle_showstate, | |
afa80ccb | 286 | .help_msg = "show-task-states(t)", |
1da177e4 LT |
287 | .action_msg = "Show State", |
288 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
289 | }; | |
290 | ||
1495cc9d | 291 | static void sysrq_handle_showstate_blocked(int key) |
e59e2ae2 IM |
292 | { |
293 | show_state_filter(TASK_UNINTERRUPTIBLE); | |
294 | } | |
295 | static struct sysrq_key_op sysrq_showstate_blocked_op = { | |
296 | .handler = sysrq_handle_showstate_blocked, | |
afa80ccb | 297 | .help_msg = "show-blocked-tasks(w)", |
e59e2ae2 IM |
298 | .action_msg = "Show Blocked State", |
299 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
300 | }; | |
301 | ||
69f698ad PZ |
302 | #ifdef CONFIG_TRACING |
303 | #include <linux/ftrace.h> | |
304 | ||
1495cc9d | 305 | static void sysrq_ftrace_dump(int key) |
69f698ad | 306 | { |
cecbca96 | 307 | ftrace_dump(DUMP_ALL); |
69f698ad PZ |
308 | } |
309 | static struct sysrq_key_op sysrq_ftrace_dump_op = { | |
310 | .handler = sysrq_ftrace_dump, | |
afa80ccb | 311 | .help_msg = "dump-ftrace-buffer(z)", |
69f698ad PZ |
312 | .action_msg = "Dump ftrace buffer", |
313 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
314 | }; | |
315 | #else | |
97f5f0cd | 316 | #define sysrq_ftrace_dump_op (*(struct sysrq_key_op *)NULL) |
69f698ad | 317 | #endif |
e59e2ae2 | 318 | |
1495cc9d | 319 | static void sysrq_handle_showmem(int key) |
1da177e4 | 320 | { |
9af744d7 | 321 | show_mem(0, NULL); |
1da177e4 LT |
322 | } |
323 | static struct sysrq_key_op sysrq_showmem_op = { | |
324 | .handler = sysrq_handle_showmem, | |
afa80ccb | 325 | .help_msg = "show-memory-usage(m)", |
1da177e4 LT |
326 | .action_msg = "Show Memory", |
327 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
328 | }; | |
329 | ||
bf36b901 AM |
330 | /* |
331 | * Signal sysrq helper function. Sends a signal to all user processes. | |
332 | */ | |
1da177e4 LT |
333 | static void send_sig_all(int sig) |
334 | { | |
335 | struct task_struct *p; | |
336 | ||
e502babe | 337 | read_lock(&tasklist_lock); |
1da177e4 | 338 | for_each_process(p) { |
d3a532a9 AV |
339 | if (p->flags & PF_KTHREAD) |
340 | continue; | |
341 | if (is_global_init(p)) | |
342 | continue; | |
343 | ||
b16503ba | 344 | do_send_sig_info(sig, SEND_SIG_PRIV, p, PIDTYPE_MAX); |
1da177e4 | 345 | } |
e502babe | 346 | read_unlock(&tasklist_lock); |
1da177e4 LT |
347 | } |
348 | ||
1495cc9d | 349 | static void sysrq_handle_term(int key) |
1da177e4 LT |
350 | { |
351 | send_sig_all(SIGTERM); | |
a8fe19eb | 352 | console_loglevel = CONSOLE_LOGLEVEL_DEBUG; |
1da177e4 LT |
353 | } |
354 | static struct sysrq_key_op sysrq_term_op = { | |
355 | .handler = sysrq_handle_term, | |
afa80ccb | 356 | .help_msg = "terminate-all-tasks(e)", |
1da177e4 LT |
357 | .action_msg = "Terminate All Tasks", |
358 | .enable_mask = SYSRQ_ENABLE_SIGNAL, | |
359 | }; | |
360 | ||
65f27f38 | 361 | static void moom_callback(struct work_struct *ignored) |
1da177e4 | 362 | { |
6e0fc46d DR |
363 | const gfp_t gfp_mask = GFP_KERNEL; |
364 | struct oom_control oc = { | |
365 | .zonelist = node_zonelist(first_memory_node, gfp_mask), | |
366 | .nodemask = NULL, | |
2a966b77 | 367 | .memcg = NULL, |
6e0fc46d | 368 | .gfp_mask = gfp_mask, |
54e9e291 | 369 | .order = -1, |
6e0fc46d DR |
370 | }; |
371 | ||
dc56401f | 372 | mutex_lock(&oom_lock); |
6e0fc46d | 373 | if (!out_of_memory(&oc)) |
d75da004 | 374 | pr_info("OOM request ignored. No task eligible\n"); |
dc56401f | 375 | mutex_unlock(&oom_lock); |
1da177e4 LT |
376 | } |
377 | ||
65f27f38 | 378 | static DECLARE_WORK(moom_work, moom_callback); |
1da177e4 | 379 | |
1495cc9d | 380 | static void sysrq_handle_moom(int key) |
1da177e4 LT |
381 | { |
382 | schedule_work(&moom_work); | |
383 | } | |
384 | static struct sysrq_key_op sysrq_moom_op = { | |
385 | .handler = sysrq_handle_moom, | |
afa80ccb | 386 | .help_msg = "memory-full-oom-kill(f)", |
1da177e4 | 387 | .action_msg = "Manual OOM execution", |
b4236f81 | 388 | .enable_mask = SYSRQ_ENABLE_SIGNAL, |
1da177e4 LT |
389 | }; |
390 | ||
c2d75438 | 391 | #ifdef CONFIG_BLOCK |
1495cc9d | 392 | static void sysrq_handle_thaw(int key) |
c2d75438 ES |
393 | { |
394 | emergency_thaw_all(); | |
395 | } | |
396 | static struct sysrq_key_op sysrq_thaw_op = { | |
397 | .handler = sysrq_handle_thaw, | |
afa80ccb | 398 | .help_msg = "thaw-filesystems(j)", |
c2d75438 ES |
399 | .action_msg = "Emergency Thaw of all frozen filesystems", |
400 | .enable_mask = SYSRQ_ENABLE_SIGNAL, | |
401 | }; | |
402 | #endif | |
403 | ||
1495cc9d | 404 | static void sysrq_handle_kill(int key) |
1da177e4 LT |
405 | { |
406 | send_sig_all(SIGKILL); | |
a8fe19eb | 407 | console_loglevel = CONSOLE_LOGLEVEL_DEBUG; |
1da177e4 LT |
408 | } |
409 | static struct sysrq_key_op sysrq_kill_op = { | |
410 | .handler = sysrq_handle_kill, | |
afa80ccb | 411 | .help_msg = "kill-all-tasks(i)", |
1da177e4 LT |
412 | .action_msg = "Kill All Tasks", |
413 | .enable_mask = SYSRQ_ENABLE_SIGNAL, | |
414 | }; | |
415 | ||
1495cc9d | 416 | static void sysrq_handle_unrt(int key) |
1da177e4 LT |
417 | { |
418 | normalize_rt_tasks(); | |
419 | } | |
420 | static struct sysrq_key_op sysrq_unrt_op = { | |
421 | .handler = sysrq_handle_unrt, | |
afa80ccb | 422 | .help_msg = "nice-all-RT-tasks(n)", |
1da177e4 LT |
423 | .action_msg = "Nice All RT Tasks", |
424 | .enable_mask = SYSRQ_ENABLE_RTNICE, | |
425 | }; | |
426 | ||
427 | /* Key Operations table and lock */ | |
428 | static DEFINE_SPINLOCK(sysrq_key_table_lock); | |
bf36b901 AM |
429 | |
430 | static struct sysrq_key_op *sysrq_key_table[36] = { | |
431 | &sysrq_loglevel_op, /* 0 */ | |
432 | &sysrq_loglevel_op, /* 1 */ | |
433 | &sysrq_loglevel_op, /* 2 */ | |
434 | &sysrq_loglevel_op, /* 3 */ | |
435 | &sysrq_loglevel_op, /* 4 */ | |
436 | &sysrq_loglevel_op, /* 5 */ | |
437 | &sysrq_loglevel_op, /* 6 */ | |
438 | &sysrq_loglevel_op, /* 7 */ | |
439 | &sysrq_loglevel_op, /* 8 */ | |
440 | &sysrq_loglevel_op, /* 9 */ | |
441 | ||
442 | /* | |
d346cce3 RD |
443 | * a: Don't use for system provided sysrqs, it is handled specially on |
444 | * sparc and will never arrive. | |
bf36b901 AM |
445 | */ |
446 | NULL, /* a */ | |
447 | &sysrq_reboot_op, /* b */ | |
5e351410 | 448 | &sysrq_crash_op, /* c */ |
bf36b901 AM |
449 | &sysrq_showlocks_op, /* d */ |
450 | &sysrq_term_op, /* e */ | |
451 | &sysrq_moom_op, /* f */ | |
364b5b7b | 452 | /* g: May be registered for the kernel debugger */ |
bf36b901 | 453 | NULL, /* g */ |
c2d75438 | 454 | NULL, /* h - reserved for help */ |
bf36b901 | 455 | &sysrq_kill_op, /* i */ |
c2d75438 ES |
456 | #ifdef CONFIG_BLOCK |
457 | &sysrq_thaw_op, /* j */ | |
458 | #else | |
bf36b901 | 459 | NULL, /* j */ |
c2d75438 | 460 | #endif |
bf36b901 | 461 | &sysrq_SAK_op, /* k */ |
5045bcae RR |
462 | #ifdef CONFIG_SMP |
463 | &sysrq_showallcpus_op, /* l */ | |
464 | #else | |
bf36b901 | 465 | NULL, /* l */ |
5045bcae | 466 | #endif |
bf36b901 AM |
467 | &sysrq_showmem_op, /* m */ |
468 | &sysrq_unrt_op, /* n */ | |
d346cce3 | 469 | /* o: This will often be registered as 'Off' at init time */ |
bf36b901 AM |
470 | NULL, /* o */ |
471 | &sysrq_showregs_op, /* p */ | |
88ad0bf6 | 472 | &sysrq_show_timers_op, /* q */ |
d346cce3 | 473 | &sysrq_unraw_op, /* r */ |
bf36b901 AM |
474 | &sysrq_sync_op, /* s */ |
475 | &sysrq_showstate_op, /* t */ | |
476 | &sysrq_mountro_op, /* u */ | |
364b5b7b | 477 | /* v: May be registered for frame buffer console restore */ |
bf36b901 | 478 | NULL, /* v */ |
d346cce3 | 479 | &sysrq_showstate_blocked_op, /* w */ |
d1e9a4f5 | 480 | /* x: May be registered on mips for TLB dump */ |
d346cce3 | 481 | /* x: May be registered on ppc/powerpc for xmon */ |
916ca14a | 482 | /* x: May be registered on sparc64 for global PMU dump */ |
3da3c68e | 483 | /* x: May be registered on x86_64 for disabling secure boot */ |
d346cce3 | 484 | NULL, /* x */ |
93dae5b7 | 485 | /* y: May be registered on sparc64 for global register dump */ |
bf36b901 | 486 | NULL, /* y */ |
69f698ad | 487 | &sysrq_ftrace_dump_op, /* z */ |
1da177e4 LT |
488 | }; |
489 | ||
490 | /* key2index calculation, -1 on invalid index */ | |
bf36b901 AM |
491 | static int sysrq_key_table_key2index(int key) |
492 | { | |
1da177e4 | 493 | int retval; |
bf36b901 AM |
494 | |
495 | if ((key >= '0') && (key <= '9')) | |
1da177e4 | 496 | retval = key - '0'; |
bf36b901 | 497 | else if ((key >= 'a') && (key <= 'z')) |
1da177e4 | 498 | retval = key + 10 - 'a'; |
bf36b901 | 499 | else |
1da177e4 | 500 | retval = -1; |
1da177e4 LT |
501 | return retval; |
502 | } | |
503 | ||
504 | /* | |
505 | * get and put functions for the table, exposed to modules. | |
506 | */ | |
bf36b901 AM |
507 | struct sysrq_key_op *__sysrq_get_key_op(int key) |
508 | { | |
509 | struct sysrq_key_op *op_p = NULL; | |
1da177e4 | 510 | int i; |
bf36b901 | 511 | |
1da177e4 | 512 | i = sysrq_key_table_key2index(key); |
bf36b901 AM |
513 | if (i != -1) |
514 | op_p = sysrq_key_table[i]; | |
97f5f0cd | 515 | |
1da177e4 LT |
516 | return op_p; |
517 | } | |
518 | ||
bf36b901 AM |
519 | static void __sysrq_put_key_op(int key, struct sysrq_key_op *op_p) |
520 | { | |
521 | int i = sysrq_key_table_key2index(key); | |
1da177e4 | 522 | |
1da177e4 LT |
523 | if (i != -1) |
524 | sysrq_key_table[i] = op_p; | |
525 | } | |
526 | ||
3da3c68e | 527 | void __handle_sysrq(int key, unsigned int from) |
1da177e4 LT |
528 | { |
529 | struct sysrq_key_op *op_p; | |
530 | int orig_log_level; | |
c39ea0b9 | 531 | int orig_suppress_printk; |
bf36b901 | 532 | int i; |
1da177e4 | 533 | |
c39ea0b9 FT |
534 | orig_suppress_printk = suppress_printk; |
535 | suppress_printk = 0; | |
536 | ||
722773af | 537 | rcu_sysrq_start(); |
984d74a7 | 538 | rcu_read_lock(); |
fb144adc AW |
539 | /* |
540 | * Raise the apparent loglevel to maximum so that the sysrq header | |
541 | * is shown to provide the user with positive feedback. We do not | |
542 | * simply emit this at KERN_EMERG as that would change message | |
543 | * routing in the consumers of /proc/kmsg. | |
544 | */ | |
1da177e4 | 545 | orig_log_level = console_loglevel; |
a8fe19eb | 546 | console_loglevel = CONSOLE_LOGLEVEL_DEFAULT; |
1da177e4 LT |
547 | |
548 | op_p = __sysrq_get_key_op(key); | |
549 | if (op_p) { | |
3da3c68e KM |
550 | /* Ban synthetic events from some sysrq functionality */ |
551 | if ((from == SYSRQ_FROM_PROC || from == SYSRQ_FROM_SYNTHETIC) && | |
552 | op_p->enable_mask & SYSRQ_DISABLE_USERSPACE) | |
553 | printk("This sysrq operation is disabled from userspace.\n"); | |
bf36b901 AM |
554 | /* |
555 | * Should we check for enabled operations (/proc/sysrq-trigger | |
556 | * should not) and is the invoked operation enabled? | |
557 | */ | |
3da3c68e | 558 | if (from == SYSRQ_FROM_KERNEL || sysrq_on_mask(op_p->enable_mask)) { |
c3fee609 | 559 | pr_info("%s\n", op_p->action_msg); |
1da177e4 | 560 | console_loglevel = orig_log_level; |
1495cc9d | 561 | op_p->handler(key); |
bf36b901 | 562 | } else { |
c3fee609 | 563 | pr_info("This sysrq operation is disabled.\n"); |
075e1a0c | 564 | console_loglevel = orig_log_level; |
bf36b901 | 565 | } |
1da177e4 | 566 | } else { |
c3fee609 | 567 | pr_info("HELP : "); |
1da177e4 | 568 | /* Only print the help msg once per handler */ |
bf36b901 AM |
569 | for (i = 0; i < ARRAY_SIZE(sysrq_key_table); i++) { |
570 | if (sysrq_key_table[i]) { | |
571 | int j; | |
572 | ||
573 | for (j = 0; sysrq_key_table[i] != | |
574 | sysrq_key_table[j]; j++) | |
575 | ; | |
576 | if (j != i) | |
577 | continue; | |
401e4a7c | 578 | pr_cont("%s ", sysrq_key_table[i]->help_msg); |
bf36b901 | 579 | } |
1da177e4 | 580 | } |
401e4a7c | 581 | pr_cont("\n"); |
1da177e4 LT |
582 | console_loglevel = orig_log_level; |
583 | } | |
984d74a7 | 584 | rcu_read_unlock(); |
722773af | 585 | rcu_sysrq_end(); |
c39ea0b9 FT |
586 | |
587 | suppress_printk = orig_suppress_printk; | |
1da177e4 LT |
588 | } |
589 | ||
f335397d | 590 | void handle_sysrq(int key) |
1da177e4 | 591 | { |
5d6f647f | 592 | if (sysrq_on()) |
3da3c68e | 593 | __handle_sysrq(key, SYSRQ_FROM_KERNEL); |
1da177e4 | 594 | } |
bf36b901 | 595 | EXPORT_SYMBOL(handle_sysrq); |
1da177e4 | 596 | |
97f5f0cd | 597 | #ifdef CONFIG_INPUT |
ffb6e0c9 | 598 | static int sysrq_reset_downtime_ms; |
97f5f0cd DT |
599 | |
600 | /* Simple translation table for the SysRq keys */ | |
fcb71930 | 601 | static const unsigned char sysrq_xlate[KEY_CNT] = |
97f5f0cd DT |
602 | "\000\0331234567890-=\177\t" /* 0x00 - 0x0f */ |
603 | "qwertyuiop[]\r\000as" /* 0x10 - 0x1f */ | |
604 | "dfghjkl;'`\000\\zxcv" /* 0x20 - 0x2f */ | |
605 | "bnm,./\000*\000 \000\201\202\203\204\205" /* 0x30 - 0x3f */ | |
606 | "\206\207\210\211\212\000\000789-456+1" /* 0x40 - 0x4f */ | |
607 | "230\177\000\000\213\214\000\000\000\000\000\000\000\000\000\000" /* 0x50 - 0x5f */ | |
608 | "\r\000/"; /* 0x60 - 0x6f */ | |
609 | ||
fcb71930 DT |
610 | struct sysrq_state { |
611 | struct input_handle handle; | |
612 | struct work_struct reinject_work; | |
613 | unsigned long key_down[BITS_TO_LONGS(KEY_CNT)]; | |
614 | unsigned int alt; | |
615 | unsigned int alt_use; | |
616 | bool active; | |
617 | bool need_reinject; | |
7ab7b5ad | 618 | bool reinjecting; |
154b7a48 MP |
619 | |
620 | /* reset sequence handling */ | |
621 | bool reset_canceled; | |
3d289517 | 622 | bool reset_requested; |
154b7a48 MP |
623 | unsigned long reset_keybit[BITS_TO_LONGS(KEY_CNT)]; |
624 | int reset_seq_len; | |
625 | int reset_seq_cnt; | |
626 | int reset_seq_version; | |
39030786 | 627 | struct timer_list keyreset_timer; |
fcb71930 DT |
628 | }; |
629 | ||
154b7a48 MP |
630 | #define SYSRQ_KEY_RESET_MAX 20 /* Should be plenty */ |
631 | static unsigned short sysrq_reset_seq[SYSRQ_KEY_RESET_MAX]; | |
632 | static unsigned int sysrq_reset_seq_len; | |
633 | static unsigned int sysrq_reset_seq_version = 1; | |
634 | ||
635 | static void sysrq_parse_reset_sequence(struct sysrq_state *state) | |
636 | { | |
637 | int i; | |
638 | unsigned short key; | |
639 | ||
640 | state->reset_seq_cnt = 0; | |
641 | ||
642 | for (i = 0; i < sysrq_reset_seq_len; i++) { | |
643 | key = sysrq_reset_seq[i]; | |
644 | ||
645 | if (key == KEY_RESERVED || key > KEY_MAX) | |
646 | break; | |
647 | ||
648 | __set_bit(key, state->reset_keybit); | |
649 | state->reset_seq_len++; | |
650 | ||
651 | if (test_bit(key, state->key_down)) | |
652 | state->reset_seq_cnt++; | |
653 | } | |
654 | ||
655 | /* Disable reset until old keys are not released */ | |
656 | state->reset_canceled = state->reset_seq_cnt != 0; | |
657 | ||
658 | state->reset_seq_version = sysrq_reset_seq_version; | |
659 | } | |
660 | ||
8c318fa9 | 661 | static void sysrq_do_reset(struct timer_list *t) |
39030786 | 662 | { |
8c318fa9 | 663 | struct sysrq_state *state = from_timer(state, t, keyreset_timer); |
3d289517 MP |
664 | |
665 | state->reset_requested = true; | |
666 | ||
8fefbc6d | 667 | orderly_reboot(); |
39030786 MP |
668 | } |
669 | ||
670 | static void sysrq_handle_reset_request(struct sysrq_state *state) | |
671 | { | |
3d289517 | 672 | if (state->reset_requested) |
3da3c68e | 673 | __handle_sysrq(sysrq_xlate[KEY_B], SYSRQ_FROM_KERNEL); |
3d289517 | 674 | |
39030786 MP |
675 | if (sysrq_reset_downtime_ms) |
676 | mod_timer(&state->keyreset_timer, | |
677 | jiffies + msecs_to_jiffies(sysrq_reset_downtime_ms)); | |
678 | else | |
8c318fa9 | 679 | sysrq_do_reset(&state->keyreset_timer); |
39030786 MP |
680 | } |
681 | ||
682 | static void sysrq_detect_reset_sequence(struct sysrq_state *state, | |
154b7a48 MP |
683 | unsigned int code, int value) |
684 | { | |
685 | if (!test_bit(code, state->reset_keybit)) { | |
686 | /* | |
687 | * Pressing any key _not_ in reset sequence cancels | |
39030786 MP |
688 | * the reset sequence. Also cancelling the timer in |
689 | * case additional keys were pressed after a reset | |
690 | * has been requested. | |
154b7a48 | 691 | */ |
39030786 | 692 | if (value && state->reset_seq_cnt) { |
154b7a48 | 693 | state->reset_canceled = true; |
39030786 MP |
694 | del_timer(&state->keyreset_timer); |
695 | } | |
154b7a48 | 696 | } else if (value == 0) { |
39030786 MP |
697 | /* |
698 | * Key release - all keys in the reset sequence need | |
699 | * to be pressed and held for the reset timeout | |
700 | * to hold. | |
701 | */ | |
702 | del_timer(&state->keyreset_timer); | |
703 | ||
154b7a48 MP |
704 | if (--state->reset_seq_cnt == 0) |
705 | state->reset_canceled = false; | |
706 | } else if (value == 1) { | |
707 | /* key press, not autorepeat */ | |
708 | if (++state->reset_seq_cnt == state->reset_seq_len && | |
709 | !state->reset_canceled) { | |
39030786 | 710 | sysrq_handle_reset_request(state); |
154b7a48 MP |
711 | } |
712 | } | |
154b7a48 MP |
713 | } |
714 | ||
4c076eb0 MP |
715 | #ifdef CONFIG_OF |
716 | static void sysrq_of_get_keyreset_config(void) | |
717 | { | |
718 | u32 key; | |
719 | struct device_node *np; | |
720 | struct property *prop; | |
721 | const __be32 *p; | |
722 | ||
723 | np = of_find_node_by_path("/chosen/linux,sysrq-reset-seq"); | |
724 | if (!np) { | |
725 | pr_debug("No sysrq node found"); | |
726 | return; | |
727 | } | |
728 | ||
729 | /* Reset in case a __weak definition was present */ | |
730 | sysrq_reset_seq_len = 0; | |
731 | ||
732 | of_property_for_each_u32(np, "keyset", prop, p, key) { | |
733 | if (key == KEY_RESERVED || key > KEY_MAX || | |
734 | sysrq_reset_seq_len == SYSRQ_KEY_RESET_MAX) | |
735 | break; | |
736 | ||
737 | sysrq_reset_seq[sysrq_reset_seq_len++] = (unsigned short)key; | |
738 | } | |
739 | ||
740 | /* Get reset timeout if any. */ | |
741 | of_property_read_u32(np, "timeout-ms", &sysrq_reset_downtime_ms); | |
279070b9 YL |
742 | |
743 | of_node_put(np); | |
4c076eb0 MP |
744 | } |
745 | #else | |
746 | static void sysrq_of_get_keyreset_config(void) | |
747 | { | |
748 | } | |
749 | #endif | |
750 | ||
fcb71930 DT |
751 | static void sysrq_reinject_alt_sysrq(struct work_struct *work) |
752 | { | |
753 | struct sysrq_state *sysrq = | |
754 | container_of(work, struct sysrq_state, reinject_work); | |
755 | struct input_handle *handle = &sysrq->handle; | |
756 | unsigned int alt_code = sysrq->alt_use; | |
757 | ||
758 | if (sysrq->need_reinject) { | |
7ab7b5ad DT |
759 | /* we do not want the assignment to be reordered */ |
760 | sysrq->reinjecting = true; | |
761 | mb(); | |
762 | ||
fcb71930 DT |
763 | /* Simulate press and release of Alt + SysRq */ |
764 | input_inject_event(handle, EV_KEY, alt_code, 1); | |
765 | input_inject_event(handle, EV_KEY, KEY_SYSRQ, 1); | |
766 | input_inject_event(handle, EV_SYN, SYN_REPORT, 1); | |
767 | ||
768 | input_inject_event(handle, EV_KEY, KEY_SYSRQ, 0); | |
769 | input_inject_event(handle, EV_KEY, alt_code, 0); | |
770 | input_inject_event(handle, EV_SYN, SYN_REPORT, 1); | |
7ab7b5ad DT |
771 | |
772 | mb(); | |
773 | sysrq->reinjecting = false; | |
fcb71930 DT |
774 | } |
775 | } | |
97f5f0cd | 776 | |
154b7a48 MP |
777 | static bool sysrq_handle_keypress(struct sysrq_state *sysrq, |
778 | unsigned int code, int value) | |
97f5f0cd | 779 | { |
fcb71930 | 780 | bool was_active = sysrq->active; |
1966cb22 DT |
781 | bool suppress; |
782 | ||
154b7a48 | 783 | switch (code) { |
7ab7b5ad | 784 | |
154b7a48 MP |
785 | case KEY_LEFTALT: |
786 | case KEY_RIGHTALT: | |
787 | if (!value) { | |
788 | /* One of ALTs is being released */ | |
789 | if (sysrq->active && code == sysrq->alt_use) | |
790 | sysrq->active = false; | |
1966cb22 | 791 | |
154b7a48 MP |
792 | sysrq->alt = KEY_RESERVED; |
793 | ||
794 | } else if (value != 2) { | |
795 | sysrq->alt = code; | |
796 | sysrq->need_reinject = false; | |
797 | } | |
fcb71930 | 798 | break; |
97f5f0cd | 799 | |
154b7a48 MP |
800 | case KEY_SYSRQ: |
801 | if (value == 1 && sysrq->alt != KEY_RESERVED) { | |
802 | sysrq->active = true; | |
803 | sysrq->alt_use = sysrq->alt; | |
804 | /* | |
805 | * If nothing else will be pressed we'll need | |
806 | * to re-inject Alt-SysRq keysroke. | |
807 | */ | |
808 | sysrq->need_reinject = true; | |
809 | } | |
97f5f0cd | 810 | |
154b7a48 MP |
811 | /* |
812 | * Pretend that sysrq was never pressed at all. This | |
813 | * is needed to properly handle KGDB which will try | |
814 | * to release all keys after exiting debugger. If we | |
815 | * do not clear key bit it KGDB will end up sending | |
816 | * release events for Alt and SysRq, potentially | |
817 | * triggering print screen function. | |
818 | */ | |
819 | if (sysrq->active) | |
820 | clear_bit(KEY_SYSRQ, sysrq->handle.dev->key); | |
f5dec511 | 821 | |
154b7a48 | 822 | break; |
fcb71930 | 823 | |
154b7a48 MP |
824 | default: |
825 | if (sysrq->active && value && value != 2) { | |
3da3c68e KM |
826 | int from = sysrq->handle.dev->flags & INPUTDEV_FLAGS_SYNTHETIC ? |
827 | SYSRQ_FROM_SYNTHETIC : 0; | |
154b7a48 | 828 | sysrq->need_reinject = false; |
3da3c68e | 829 | __handle_sysrq(sysrq_xlate[code], from); |
154b7a48 MP |
830 | } |
831 | break; | |
832 | } | |
fcb71930 | 833 | |
154b7a48 | 834 | suppress = sysrq->active; |
fcb71930 | 835 | |
154b7a48 | 836 | if (!sysrq->active) { |
fcb71930 | 837 | |
154b7a48 MP |
838 | /* |
839 | * See if reset sequence has changed since the last time. | |
840 | */ | |
841 | if (sysrq->reset_seq_version != sysrq_reset_seq_version) | |
842 | sysrq_parse_reset_sequence(sysrq); | |
fcb71930 | 843 | |
154b7a48 MP |
844 | /* |
845 | * If we are not suppressing key presses keep track of | |
846 | * keyboard state so we can release keys that have been | |
847 | * pressed before entering SysRq mode. | |
848 | */ | |
849 | if (value) | |
850 | set_bit(code, sysrq->key_down); | |
851 | else | |
852 | clear_bit(code, sysrq->key_down); | |
853 | ||
854 | if (was_active) | |
855 | schedule_work(&sysrq->reinject_work); | |
856 | ||
39030786 MP |
857 | /* Check for reset sequence */ |
858 | sysrq_detect_reset_sequence(sysrq, code, value); | |
97f5f0cd | 859 | |
154b7a48 MP |
860 | } else if (value == 0 && test_and_clear_bit(code, sysrq->key_down)) { |
861 | /* | |
862 | * Pass on release events for keys that was pressed before | |
863 | * entering SysRq mode. | |
864 | */ | |
865 | suppress = false; | |
866 | } | |
fcb71930 | 867 | |
154b7a48 MP |
868 | return suppress; |
869 | } | |
fcb71930 | 870 | |
154b7a48 MP |
871 | static bool sysrq_filter(struct input_handle *handle, |
872 | unsigned int type, unsigned int code, int value) | |
873 | { | |
874 | struct sysrq_state *sysrq = handle->private; | |
875 | bool suppress; | |
fcb71930 | 876 | |
154b7a48 MP |
877 | /* |
878 | * Do not filter anything if we are in the process of re-injecting | |
879 | * Alt+SysRq combination. | |
880 | */ | |
881 | if (sysrq->reinjecting) | |
882 | return false; | |
883 | ||
884 | switch (type) { | |
885 | ||
886 | case EV_SYN: | |
887 | suppress = false; | |
888 | break; | |
889 | ||
890 | case EV_KEY: | |
891 | suppress = sysrq_handle_keypress(sysrq, code, value); | |
97f5f0cd DT |
892 | break; |
893 | ||
894 | default: | |
fcb71930 | 895 | suppress = sysrq->active; |
97f5f0cd DT |
896 | break; |
897 | } | |
898 | ||
1966cb22 | 899 | return suppress; |
97f5f0cd DT |
900 | } |
901 | ||
902 | static int sysrq_connect(struct input_handler *handler, | |
903 | struct input_dev *dev, | |
904 | const struct input_device_id *id) | |
905 | { | |
fcb71930 | 906 | struct sysrq_state *sysrq; |
97f5f0cd DT |
907 | int error; |
908 | ||
fcb71930 DT |
909 | sysrq = kzalloc(sizeof(struct sysrq_state), GFP_KERNEL); |
910 | if (!sysrq) | |
97f5f0cd DT |
911 | return -ENOMEM; |
912 | ||
fcb71930 DT |
913 | INIT_WORK(&sysrq->reinject_work, sysrq_reinject_alt_sysrq); |
914 | ||
915 | sysrq->handle.dev = dev; | |
916 | sysrq->handle.handler = handler; | |
917 | sysrq->handle.name = "sysrq"; | |
918 | sysrq->handle.private = sysrq; | |
8c318fa9 | 919 | timer_setup(&sysrq->keyreset_timer, sysrq_do_reset, 0); |
97f5f0cd | 920 | |
fcb71930 | 921 | error = input_register_handle(&sysrq->handle); |
97f5f0cd DT |
922 | if (error) { |
923 | pr_err("Failed to register input sysrq handler, error %d\n", | |
924 | error); | |
925 | goto err_free; | |
926 | } | |
927 | ||
fcb71930 | 928 | error = input_open_device(&sysrq->handle); |
97f5f0cd DT |
929 | if (error) { |
930 | pr_err("Failed to open input device, error %d\n", error); | |
931 | goto err_unregister; | |
932 | } | |
933 | ||
934 | return 0; | |
935 | ||
936 | err_unregister: | |
fcb71930 | 937 | input_unregister_handle(&sysrq->handle); |
97f5f0cd | 938 | err_free: |
fcb71930 | 939 | kfree(sysrq); |
97f5f0cd DT |
940 | return error; |
941 | } | |
942 | ||
943 | static void sysrq_disconnect(struct input_handle *handle) | |
944 | { | |
fcb71930 DT |
945 | struct sysrq_state *sysrq = handle->private; |
946 | ||
97f5f0cd | 947 | input_close_device(handle); |
fcb71930 | 948 | cancel_work_sync(&sysrq->reinject_work); |
39030786 | 949 | del_timer_sync(&sysrq->keyreset_timer); |
97f5f0cd | 950 | input_unregister_handle(handle); |
fcb71930 | 951 | kfree(sysrq); |
97f5f0cd DT |
952 | } |
953 | ||
954 | /* | |
1966cb22 DT |
955 | * We are matching on KEY_LEFTALT instead of KEY_SYSRQ because not all |
956 | * keyboards have SysRq key predefined and so user may add it to keymap | |
97f5f0cd DT |
957 | * later, but we expect all such keyboards to have left alt. |
958 | */ | |
959 | static const struct input_device_id sysrq_ids[] = { | |
960 | { | |
961 | .flags = INPUT_DEVICE_ID_MATCH_EVBIT | | |
962 | INPUT_DEVICE_ID_MATCH_KEYBIT, | |
802c0388 AM |
963 | .evbit = { [BIT_WORD(EV_KEY)] = BIT_MASK(EV_KEY) }, |
964 | .keybit = { [BIT_WORD(KEY_LEFTALT)] = BIT_MASK(KEY_LEFTALT) }, | |
97f5f0cd DT |
965 | }, |
966 | { }, | |
967 | }; | |
968 | ||
969 | static struct input_handler sysrq_handler = { | |
970 | .filter = sysrq_filter, | |
971 | .connect = sysrq_connect, | |
972 | .disconnect = sysrq_disconnect, | |
973 | .name = "sysrq", | |
974 | .id_table = sysrq_ids, | |
975 | }; | |
976 | ||
977 | static bool sysrq_handler_registered; | |
978 | ||
979 | static inline void sysrq_register_handler(void) | |
980 | { | |
981 | int error; | |
982 | ||
4c076eb0 MP |
983 | sysrq_of_get_keyreset_config(); |
984 | ||
97f5f0cd DT |
985 | error = input_register_handler(&sysrq_handler); |
986 | if (error) | |
987 | pr_err("Failed to register input handler, error %d", error); | |
988 | else | |
989 | sysrq_handler_registered = true; | |
990 | } | |
991 | ||
992 | static inline void sysrq_unregister_handler(void) | |
993 | { | |
994 | if (sysrq_handler_registered) { | |
995 | input_unregister_handler(&sysrq_handler); | |
996 | sysrq_handler_registered = false; | |
997 | } | |
998 | } | |
999 | ||
154b7a48 MP |
1000 | static int sysrq_reset_seq_param_set(const char *buffer, |
1001 | const struct kernel_param *kp) | |
1002 | { | |
1003 | unsigned long val; | |
1004 | int error; | |
1005 | ||
86b40567 | 1006 | error = kstrtoul(buffer, 0, &val); |
154b7a48 MP |
1007 | if (error < 0) |
1008 | return error; | |
1009 | ||
1010 | if (val > KEY_MAX) | |
1011 | return -EINVAL; | |
1012 | ||
1013 | *((unsigned short *)kp->arg) = val; | |
1014 | sysrq_reset_seq_version++; | |
1015 | ||
1016 | return 0; | |
1017 | } | |
1018 | ||
9c27847d | 1019 | static const struct kernel_param_ops param_ops_sysrq_reset_seq = { |
154b7a48 MP |
1020 | .get = param_get_ushort, |
1021 | .set = sysrq_reset_seq_param_set, | |
1022 | }; | |
1023 | ||
1024 | #define param_check_sysrq_reset_seq(name, p) \ | |
1025 | __param_check(name, p, unsigned short) | |
1026 | ||
3bce6f64 PG |
1027 | /* |
1028 | * not really modular, but the easiest way to keep compat with existing | |
1029 | * bootargs behaviour is to continue using module_param here. | |
1030 | */ | |
154b7a48 MP |
1031 | module_param_array_named(reset_seq, sysrq_reset_seq, sysrq_reset_seq, |
1032 | &sysrq_reset_seq_len, 0644); | |
1033 | ||
39030786 MP |
1034 | module_param_named(sysrq_downtime_ms, sysrq_reset_downtime_ms, int, 0644); |
1035 | ||
97f5f0cd DT |
1036 | #else |
1037 | ||
1038 | static inline void sysrq_register_handler(void) | |
1039 | { | |
1040 | } | |
1041 | ||
1042 | static inline void sysrq_unregister_handler(void) | |
1043 | { | |
1044 | } | |
1045 | ||
1046 | #endif /* CONFIG_INPUT */ | |
1047 | ||
1048 | int sysrq_toggle_support(int enable_mask) | |
1049 | { | |
1050 | bool was_enabled = sysrq_on(); | |
1051 | ||
1052 | sysrq_enabled = enable_mask; | |
1053 | ||
1054 | if (was_enabled != sysrq_on()) { | |
1055 | if (sysrq_on()) | |
1056 | sysrq_register_handler(); | |
1057 | else | |
1058 | sysrq_unregister_handler(); | |
1059 | } | |
1060 | ||
1061 | return 0; | |
1062 | } | |
1063 | ||
cf62ddce | 1064 | static int __sysrq_swap_key_ops(int key, struct sysrq_key_op *insert_op_p, |
bf36b901 AM |
1065 | struct sysrq_key_op *remove_op_p) |
1066 | { | |
1da177e4 | 1067 | int retval; |
1da177e4 | 1068 | |
984d74a7 | 1069 | spin_lock(&sysrq_key_table_lock); |
1da177e4 LT |
1070 | if (__sysrq_get_key_op(key) == remove_op_p) { |
1071 | __sysrq_put_key_op(key, insert_op_p); | |
1072 | retval = 0; | |
1073 | } else { | |
1074 | retval = -1; | |
1075 | } | |
984d74a7 RR |
1076 | spin_unlock(&sysrq_key_table_lock); |
1077 | ||
1078 | /* | |
1079 | * A concurrent __handle_sysrq either got the old op or the new op. | |
1080 | * Wait for it to go away before returning, so the code for an old | |
1081 | * op is not freed (eg. on module unload) while it is in use. | |
1082 | */ | |
1083 | synchronize_rcu(); | |
1084 | ||
1da177e4 LT |
1085 | return retval; |
1086 | } | |
1087 | ||
1088 | int register_sysrq_key(int key, struct sysrq_key_op *op_p) | |
1089 | { | |
1090 | return __sysrq_swap_key_ops(key, op_p, NULL); | |
1091 | } | |
bf36b901 | 1092 | EXPORT_SYMBOL(register_sysrq_key); |
1da177e4 LT |
1093 | |
1094 | int unregister_sysrq_key(int key, struct sysrq_key_op *op_p) | |
1095 | { | |
1096 | return __sysrq_swap_key_ops(key, NULL, op_p); | |
1097 | } | |
1da177e4 | 1098 | EXPORT_SYMBOL(unregister_sysrq_key); |
f40cbaa5 AD |
1099 | |
1100 | #ifdef CONFIG_PROC_FS | |
1101 | /* | |
1102 | * writing 'C' to /proc/sysrq-trigger is like sysrq-C | |
1103 | */ | |
1104 | static ssize_t write_sysrq_trigger(struct file *file, const char __user *buf, | |
1105 | size_t count, loff_t *ppos) | |
1106 | { | |
1107 | if (count) { | |
1108 | char c; | |
1109 | ||
1110 | if (get_user(c, buf)) | |
1111 | return -EFAULT; | |
3da3c68e | 1112 | __handle_sysrq(c, SYSRQ_FROM_PROC); |
f40cbaa5 | 1113 | } |
97f5f0cd | 1114 | |
f40cbaa5 AD |
1115 | return count; |
1116 | } | |
1117 | ||
1118 | static const struct file_operations proc_sysrq_trigger_operations = { | |
1119 | .write = write_sysrq_trigger, | |
6038f373 | 1120 | .llseek = noop_llseek, |
f40cbaa5 AD |
1121 | }; |
1122 | ||
97f5f0cd DT |
1123 | static void sysrq_init_procfs(void) |
1124 | { | |
1125 | if (!proc_create("sysrq-trigger", S_IWUSR, NULL, | |
1126 | &proc_sysrq_trigger_operations)) | |
1127 | pr_err("Failed to register proc interface\n"); | |
1128 | } | |
1129 | ||
1130 | #else | |
1131 | ||
1132 | static inline void sysrq_init_procfs(void) | |
1133 | { | |
1134 | } | |
1135 | ||
1136 | #endif /* CONFIG_PROC_FS */ | |
1137 | ||
f40cbaa5 AD |
1138 | static int __init sysrq_init(void) |
1139 | { | |
97f5f0cd DT |
1140 | sysrq_init_procfs(); |
1141 | ||
1142 | if (sysrq_on()) | |
1143 | sysrq_register_handler(); | |
1144 | ||
f40cbaa5 AD |
1145 | return 0; |
1146 | } | |
3bce6f64 | 1147 | device_initcall(sysrq_init); |