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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 | ||
eaee4172 DS |
66 | /** |
67 | * sysrq_mask - Getter for sysrq_enabled mask. | |
68 | * | |
69 | * Return: 1 if sysrq is always enabled, enabled sysrq_key_op mask otherwise. | |
70 | */ | |
71 | int sysrq_mask(void) | |
72 | { | |
73 | if (sysrq_always_enabled) | |
74 | return 1; | |
75 | return sysrq_enabled; | |
76 | } | |
77 | ||
5d6f647f IM |
78 | /* |
79 | * A value of 1 means 'all', other nonzero values are an op mask: | |
80 | */ | |
97f5f0cd | 81 | static bool sysrq_on_mask(int mask) |
5d6f647f | 82 | { |
97f5f0cd DT |
83 | return sysrq_always_enabled || |
84 | sysrq_enabled == 1 || | |
85 | (sysrq_enabled & mask); | |
5d6f647f IM |
86 | } |
87 | ||
88 | static int __init sysrq_always_enabled_setup(char *str) | |
89 | { | |
97f5f0cd DT |
90 | sysrq_always_enabled = true; |
91 | pr_info("sysrq always enabled.\n"); | |
5d6f647f IM |
92 | |
93 | return 1; | |
94 | } | |
95 | ||
96 | __setup("sysrq_always_enabled", sysrq_always_enabled_setup); | |
97 | ||
1da177e4 | 98 | |
1495cc9d | 99 | static void sysrq_handle_loglevel(int key) |
1da177e4 LT |
100 | { |
101 | int i; | |
97f5f0cd | 102 | |
1da177e4 | 103 | i = key - '0'; |
a8fe19eb | 104 | console_loglevel = CONSOLE_LOGLEVEL_DEFAULT; |
401e4a7c | 105 | pr_info("Loglevel set to %d\n", i); |
1da177e4 | 106 | console_loglevel = i; |
bf36b901 | 107 | } |
1da177e4 LT |
108 | static struct sysrq_key_op sysrq_loglevel_op = { |
109 | .handler = sysrq_handle_loglevel, | |
208b95ce | 110 | .help_msg = "loglevel(0-9)", |
1da177e4 LT |
111 | .action_msg = "Changing Loglevel", |
112 | .enable_mask = SYSRQ_ENABLE_LOG, | |
113 | }; | |
114 | ||
1da177e4 | 115 | #ifdef CONFIG_VT |
1495cc9d | 116 | static void sysrq_handle_SAK(int key) |
1da177e4 | 117 | { |
8b6312f4 | 118 | struct work_struct *SAK_work = &vc_cons[fg_console].SAK_work; |
8b6312f4 | 119 | schedule_work(SAK_work); |
1da177e4 LT |
120 | } |
121 | static struct sysrq_key_op sysrq_SAK_op = { | |
122 | .handler = sysrq_handle_SAK, | |
afa80ccb | 123 | .help_msg = "sak(k)", |
1da177e4 LT |
124 | .action_msg = "SAK", |
125 | .enable_mask = SYSRQ_ENABLE_KEYBOARD, | |
126 | }; | |
bf36b901 | 127 | #else |
97f5f0cd | 128 | #define sysrq_SAK_op (*(struct sysrq_key_op *)NULL) |
1da177e4 LT |
129 | #endif |
130 | ||
131 | #ifdef CONFIG_VT | |
1495cc9d | 132 | static void sysrq_handle_unraw(int key) |
1da177e4 | 133 | { |
079c9534 | 134 | vt_reset_unicode(fg_console); |
1da177e4 | 135 | } |
079c9534 | 136 | |
1da177e4 LT |
137 | static struct sysrq_key_op sysrq_unraw_op = { |
138 | .handler = sysrq_handle_unraw, | |
afa80ccb | 139 | .help_msg = "unraw(r)", |
2e8ecb9d | 140 | .action_msg = "Keyboard mode set to system default", |
1da177e4 LT |
141 | .enable_mask = SYSRQ_ENABLE_KEYBOARD, |
142 | }; | |
bf36b901 | 143 | #else |
97f5f0cd | 144 | #define sysrq_unraw_op (*(struct sysrq_key_op *)NULL) |
1da177e4 LT |
145 | #endif /* CONFIG_VT */ |
146 | ||
1495cc9d | 147 | static void sysrq_handle_crash(int key) |
86b1ae38 | 148 | { |
8341f2f2 | 149 | /* release the RCU read lock before crashing */ |
984cf355 | 150 | rcu_read_unlock(); |
8341f2f2 MK |
151 | |
152 | panic("sysrq triggered crash\n"); | |
86b1ae38 | 153 | } |
cab8bd34 | 154 | static struct sysrq_key_op sysrq_crash_op = { |
d6580a9f | 155 | .handler = sysrq_handle_crash, |
afa80ccb | 156 | .help_msg = "crash(c)", |
d6580a9f | 157 | .action_msg = "Trigger a crash", |
86b1ae38 HN |
158 | .enable_mask = SYSRQ_ENABLE_DUMP, |
159 | }; | |
86b1ae38 | 160 | |
1495cc9d | 161 | static void sysrq_handle_reboot(int key) |
1da177e4 | 162 | { |
b2e9c7d0 | 163 | lockdep_off(); |
1da177e4 | 164 | local_irq_enable(); |
4de8b9b7 | 165 | emergency_restart(); |
1da177e4 | 166 | } |
1da177e4 LT |
167 | static struct sysrq_key_op sysrq_reboot_op = { |
168 | .handler = sysrq_handle_reboot, | |
afa80ccb | 169 | .help_msg = "reboot(b)", |
1da177e4 LT |
170 | .action_msg = "Resetting", |
171 | .enable_mask = SYSRQ_ENABLE_BOOT, | |
172 | }; | |
173 | ||
1495cc9d | 174 | static void sysrq_handle_sync(int key) |
1da177e4 LT |
175 | { |
176 | emergency_sync(); | |
177 | } | |
1da177e4 LT |
178 | static struct sysrq_key_op sysrq_sync_op = { |
179 | .handler = sysrq_handle_sync, | |
afa80ccb | 180 | .help_msg = "sync(s)", |
1da177e4 LT |
181 | .action_msg = "Emergency Sync", |
182 | .enable_mask = SYSRQ_ENABLE_SYNC, | |
183 | }; | |
184 | ||
1495cc9d | 185 | static void sysrq_handle_show_timers(int key) |
88ad0bf6 IM |
186 | { |
187 | sysrq_timer_list_show(); | |
188 | } | |
189 | ||
190 | static struct sysrq_key_op sysrq_show_timers_op = { | |
191 | .handler = sysrq_handle_show_timers, | |
afa80ccb | 192 | .help_msg = "show-all-timers(q)", |
322acf65 | 193 | .action_msg = "Show clockevent devices & pending hrtimers (no others)", |
88ad0bf6 IM |
194 | }; |
195 | ||
1495cc9d | 196 | static void sysrq_handle_mountro(int key) |
1da177e4 LT |
197 | { |
198 | emergency_remount(); | |
199 | } | |
1da177e4 LT |
200 | static struct sysrq_key_op sysrq_mountro_op = { |
201 | .handler = sysrq_handle_mountro, | |
afa80ccb | 202 | .help_msg = "unmount(u)", |
1da177e4 LT |
203 | .action_msg = "Emergency Remount R/O", |
204 | .enable_mask = SYSRQ_ENABLE_REMOUNT, | |
205 | }; | |
206 | ||
8c64580d | 207 | #ifdef CONFIG_LOCKDEP |
1495cc9d | 208 | static void sysrq_handle_showlocks(int key) |
de5097c2 | 209 | { |
9a11b49a | 210 | debug_show_all_locks(); |
de5097c2 | 211 | } |
8c64580d | 212 | |
de5097c2 IM |
213 | static struct sysrq_key_op sysrq_showlocks_op = { |
214 | .handler = sysrq_handle_showlocks, | |
afa80ccb | 215 | .help_msg = "show-all-locks(d)", |
de5097c2 IM |
216 | .action_msg = "Show Locks Held", |
217 | }; | |
bf36b901 | 218 | #else |
97f5f0cd | 219 | #define sysrq_showlocks_op (*(struct sysrq_key_op *)NULL) |
de5097c2 | 220 | #endif |
1da177e4 | 221 | |
5045bcae | 222 | #ifdef CONFIG_SMP |
6ac972dd | 223 | static DEFINE_RAW_SPINLOCK(show_lock); |
5045bcae RR |
224 | |
225 | static void showacpu(void *dummy) | |
226 | { | |
227 | unsigned long flags; | |
228 | ||
229 | /* Idle CPUs have no interesting backtrace. */ | |
230 | if (idle_cpu(smp_processor_id())) | |
231 | return; | |
232 | ||
6ac972dd | 233 | raw_spin_lock_irqsave(&show_lock, flags); |
401e4a7c | 234 | pr_info("CPU%d:\n", smp_processor_id()); |
5045bcae | 235 | show_stack(NULL, NULL); |
6ac972dd | 236 | raw_spin_unlock_irqrestore(&show_lock, flags); |
5045bcae RR |
237 | } |
238 | ||
239 | static void sysrq_showregs_othercpus(struct work_struct *dummy) | |
240 | { | |
8b604d52 | 241 | smp_call_function(showacpu, NULL, 0); |
5045bcae RR |
242 | } |
243 | ||
244 | static DECLARE_WORK(sysrq_showallcpus, sysrq_showregs_othercpus); | |
245 | ||
1495cc9d | 246 | static void sysrq_handle_showallcpus(int key) |
5045bcae | 247 | { |
47cab6a7 IM |
248 | /* |
249 | * Fall back to the workqueue based printing if the | |
250 | * backtrace printing did not succeed or the | |
251 | * architecture has no support for it: | |
252 | */ | |
253 | if (!trigger_all_cpu_backtrace()) { | |
b00bebbc | 254 | struct pt_regs *regs = NULL; |
47cab6a7 | 255 | |
b00bebbc JX |
256 | if (in_irq()) |
257 | regs = get_irq_regs(); | |
47cab6a7 | 258 | if (regs) { |
401e4a7c | 259 | pr_info("CPU%d:\n", smp_processor_id()); |
47cab6a7 IM |
260 | show_regs(regs); |
261 | } | |
262 | schedule_work(&sysrq_showallcpus); | |
263 | } | |
5045bcae RR |
264 | } |
265 | ||
266 | static struct sysrq_key_op sysrq_showallcpus_op = { | |
267 | .handler = sysrq_handle_showallcpus, | |
afa80ccb | 268 | .help_msg = "show-backtrace-all-active-cpus(l)", |
5045bcae RR |
269 | .action_msg = "Show backtrace of all active CPUs", |
270 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
271 | }; | |
272 | #endif | |
273 | ||
1495cc9d | 274 | static void sysrq_handle_showregs(int key) |
1da177e4 | 275 | { |
b00bebbc JX |
276 | struct pt_regs *regs = NULL; |
277 | ||
278 | if (in_irq()) | |
279 | regs = get_irq_regs(); | |
7d12e780 DH |
280 | if (regs) |
281 | show_regs(regs); | |
cdd6c482 | 282 | perf_event_print_debug(); |
1da177e4 LT |
283 | } |
284 | static struct sysrq_key_op sysrq_showregs_op = { | |
285 | .handler = sysrq_handle_showregs, | |
afa80ccb | 286 | .help_msg = "show-registers(p)", |
1da177e4 LT |
287 | .action_msg = "Show Regs", |
288 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
289 | }; | |
290 | ||
1495cc9d | 291 | static void sysrq_handle_showstate(int key) |
1da177e4 LT |
292 | { |
293 | show_state(); | |
3494fc30 | 294 | show_workqueue_state(); |
1da177e4 LT |
295 | } |
296 | static struct sysrq_key_op sysrq_showstate_op = { | |
297 | .handler = sysrq_handle_showstate, | |
afa80ccb | 298 | .help_msg = "show-task-states(t)", |
1da177e4 LT |
299 | .action_msg = "Show State", |
300 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
301 | }; | |
302 | ||
1495cc9d | 303 | static void sysrq_handle_showstate_blocked(int key) |
e59e2ae2 IM |
304 | { |
305 | show_state_filter(TASK_UNINTERRUPTIBLE); | |
306 | } | |
307 | static struct sysrq_key_op sysrq_showstate_blocked_op = { | |
308 | .handler = sysrq_handle_showstate_blocked, | |
afa80ccb | 309 | .help_msg = "show-blocked-tasks(w)", |
e59e2ae2 IM |
310 | .action_msg = "Show Blocked State", |
311 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
312 | }; | |
313 | ||
69f698ad PZ |
314 | #ifdef CONFIG_TRACING |
315 | #include <linux/ftrace.h> | |
316 | ||
1495cc9d | 317 | static void sysrq_ftrace_dump(int key) |
69f698ad | 318 | { |
cecbca96 | 319 | ftrace_dump(DUMP_ALL); |
69f698ad PZ |
320 | } |
321 | static struct sysrq_key_op sysrq_ftrace_dump_op = { | |
322 | .handler = sysrq_ftrace_dump, | |
afa80ccb | 323 | .help_msg = "dump-ftrace-buffer(z)", |
69f698ad PZ |
324 | .action_msg = "Dump ftrace buffer", |
325 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
326 | }; | |
327 | #else | |
97f5f0cd | 328 | #define sysrq_ftrace_dump_op (*(struct sysrq_key_op *)NULL) |
69f698ad | 329 | #endif |
e59e2ae2 | 330 | |
1495cc9d | 331 | static void sysrq_handle_showmem(int key) |
1da177e4 | 332 | { |
9af744d7 | 333 | show_mem(0, NULL); |
1da177e4 LT |
334 | } |
335 | static struct sysrq_key_op sysrq_showmem_op = { | |
336 | .handler = sysrq_handle_showmem, | |
afa80ccb | 337 | .help_msg = "show-memory-usage(m)", |
1da177e4 LT |
338 | .action_msg = "Show Memory", |
339 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
340 | }; | |
341 | ||
bf36b901 AM |
342 | /* |
343 | * Signal sysrq helper function. Sends a signal to all user processes. | |
344 | */ | |
1da177e4 LT |
345 | static void send_sig_all(int sig) |
346 | { | |
347 | struct task_struct *p; | |
348 | ||
e502babe | 349 | read_lock(&tasklist_lock); |
1da177e4 | 350 | for_each_process(p) { |
d3a532a9 AV |
351 | if (p->flags & PF_KTHREAD) |
352 | continue; | |
353 | if (is_global_init(p)) | |
354 | continue; | |
355 | ||
b16503ba | 356 | do_send_sig_info(sig, SEND_SIG_PRIV, p, PIDTYPE_MAX); |
1da177e4 | 357 | } |
e502babe | 358 | read_unlock(&tasklist_lock); |
1da177e4 LT |
359 | } |
360 | ||
1495cc9d | 361 | static void sysrq_handle_term(int key) |
1da177e4 LT |
362 | { |
363 | send_sig_all(SIGTERM); | |
a8fe19eb | 364 | console_loglevel = CONSOLE_LOGLEVEL_DEBUG; |
1da177e4 LT |
365 | } |
366 | static struct sysrq_key_op sysrq_term_op = { | |
367 | .handler = sysrq_handle_term, | |
afa80ccb | 368 | .help_msg = "terminate-all-tasks(e)", |
1da177e4 LT |
369 | .action_msg = "Terminate All Tasks", |
370 | .enable_mask = SYSRQ_ENABLE_SIGNAL, | |
371 | }; | |
372 | ||
65f27f38 | 373 | static void moom_callback(struct work_struct *ignored) |
1da177e4 | 374 | { |
6e0fc46d DR |
375 | const gfp_t gfp_mask = GFP_KERNEL; |
376 | struct oom_control oc = { | |
377 | .zonelist = node_zonelist(first_memory_node, gfp_mask), | |
378 | .nodemask = NULL, | |
2a966b77 | 379 | .memcg = NULL, |
6e0fc46d | 380 | .gfp_mask = gfp_mask, |
54e9e291 | 381 | .order = -1, |
6e0fc46d DR |
382 | }; |
383 | ||
dc56401f | 384 | mutex_lock(&oom_lock); |
6e0fc46d | 385 | if (!out_of_memory(&oc)) |
d75da004 | 386 | pr_info("OOM request ignored. No task eligible\n"); |
dc56401f | 387 | mutex_unlock(&oom_lock); |
1da177e4 LT |
388 | } |
389 | ||
65f27f38 | 390 | static DECLARE_WORK(moom_work, moom_callback); |
1da177e4 | 391 | |
1495cc9d | 392 | static void sysrq_handle_moom(int key) |
1da177e4 LT |
393 | { |
394 | schedule_work(&moom_work); | |
395 | } | |
396 | static struct sysrq_key_op sysrq_moom_op = { | |
397 | .handler = sysrq_handle_moom, | |
afa80ccb | 398 | .help_msg = "memory-full-oom-kill(f)", |
1da177e4 | 399 | .action_msg = "Manual OOM execution", |
b4236f81 | 400 | .enable_mask = SYSRQ_ENABLE_SIGNAL, |
1da177e4 LT |
401 | }; |
402 | ||
c2d75438 | 403 | #ifdef CONFIG_BLOCK |
1495cc9d | 404 | static void sysrq_handle_thaw(int key) |
c2d75438 ES |
405 | { |
406 | emergency_thaw_all(); | |
407 | } | |
408 | static struct sysrq_key_op sysrq_thaw_op = { | |
409 | .handler = sysrq_handle_thaw, | |
afa80ccb | 410 | .help_msg = "thaw-filesystems(j)", |
c2d75438 ES |
411 | .action_msg = "Emergency Thaw of all frozen filesystems", |
412 | .enable_mask = SYSRQ_ENABLE_SIGNAL, | |
413 | }; | |
414 | #endif | |
415 | ||
1495cc9d | 416 | static void sysrq_handle_kill(int key) |
1da177e4 LT |
417 | { |
418 | send_sig_all(SIGKILL); | |
a8fe19eb | 419 | console_loglevel = CONSOLE_LOGLEVEL_DEBUG; |
1da177e4 LT |
420 | } |
421 | static struct sysrq_key_op sysrq_kill_op = { | |
422 | .handler = sysrq_handle_kill, | |
afa80ccb | 423 | .help_msg = "kill-all-tasks(i)", |
1da177e4 LT |
424 | .action_msg = "Kill All Tasks", |
425 | .enable_mask = SYSRQ_ENABLE_SIGNAL, | |
426 | }; | |
427 | ||
1495cc9d | 428 | static void sysrq_handle_unrt(int key) |
1da177e4 LT |
429 | { |
430 | normalize_rt_tasks(); | |
431 | } | |
432 | static struct sysrq_key_op sysrq_unrt_op = { | |
433 | .handler = sysrq_handle_unrt, | |
afa80ccb | 434 | .help_msg = "nice-all-RT-tasks(n)", |
1da177e4 LT |
435 | .action_msg = "Nice All RT Tasks", |
436 | .enable_mask = SYSRQ_ENABLE_RTNICE, | |
437 | }; | |
438 | ||
439 | /* Key Operations table and lock */ | |
440 | static DEFINE_SPINLOCK(sysrq_key_table_lock); | |
bf36b901 AM |
441 | |
442 | static struct sysrq_key_op *sysrq_key_table[36] = { | |
443 | &sysrq_loglevel_op, /* 0 */ | |
444 | &sysrq_loglevel_op, /* 1 */ | |
445 | &sysrq_loglevel_op, /* 2 */ | |
446 | &sysrq_loglevel_op, /* 3 */ | |
447 | &sysrq_loglevel_op, /* 4 */ | |
448 | &sysrq_loglevel_op, /* 5 */ | |
449 | &sysrq_loglevel_op, /* 6 */ | |
450 | &sysrq_loglevel_op, /* 7 */ | |
451 | &sysrq_loglevel_op, /* 8 */ | |
452 | &sysrq_loglevel_op, /* 9 */ | |
453 | ||
454 | /* | |
d346cce3 RD |
455 | * a: Don't use for system provided sysrqs, it is handled specially on |
456 | * sparc and will never arrive. | |
bf36b901 AM |
457 | */ |
458 | NULL, /* a */ | |
459 | &sysrq_reboot_op, /* b */ | |
5e351410 | 460 | &sysrq_crash_op, /* c */ |
bf36b901 AM |
461 | &sysrq_showlocks_op, /* d */ |
462 | &sysrq_term_op, /* e */ | |
463 | &sysrq_moom_op, /* f */ | |
364b5b7b | 464 | /* g: May be registered for the kernel debugger */ |
bf36b901 | 465 | NULL, /* g */ |
c2d75438 | 466 | NULL, /* h - reserved for help */ |
bf36b901 | 467 | &sysrq_kill_op, /* i */ |
c2d75438 ES |
468 | #ifdef CONFIG_BLOCK |
469 | &sysrq_thaw_op, /* j */ | |
470 | #else | |
bf36b901 | 471 | NULL, /* j */ |
c2d75438 | 472 | #endif |
bf36b901 | 473 | &sysrq_SAK_op, /* k */ |
5045bcae RR |
474 | #ifdef CONFIG_SMP |
475 | &sysrq_showallcpus_op, /* l */ | |
476 | #else | |
bf36b901 | 477 | NULL, /* l */ |
5045bcae | 478 | #endif |
bf36b901 AM |
479 | &sysrq_showmem_op, /* m */ |
480 | &sysrq_unrt_op, /* n */ | |
d346cce3 | 481 | /* o: This will often be registered as 'Off' at init time */ |
bf36b901 AM |
482 | NULL, /* o */ |
483 | &sysrq_showregs_op, /* p */ | |
88ad0bf6 | 484 | &sysrq_show_timers_op, /* q */ |
d346cce3 | 485 | &sysrq_unraw_op, /* r */ |
bf36b901 AM |
486 | &sysrq_sync_op, /* s */ |
487 | &sysrq_showstate_op, /* t */ | |
488 | &sysrq_mountro_op, /* u */ | |
364b5b7b | 489 | /* v: May be registered for frame buffer console restore */ |
bf36b901 | 490 | NULL, /* v */ |
d346cce3 | 491 | &sysrq_showstate_blocked_op, /* w */ |
d1e9a4f5 | 492 | /* x: May be registered on mips for TLB dump */ |
d346cce3 | 493 | /* x: May be registered on ppc/powerpc for xmon */ |
916ca14a | 494 | /* x: May be registered on sparc64 for global PMU dump */ |
d346cce3 | 495 | NULL, /* x */ |
93dae5b7 | 496 | /* y: May be registered on sparc64 for global register dump */ |
bf36b901 | 497 | NULL, /* y */ |
69f698ad | 498 | &sysrq_ftrace_dump_op, /* z */ |
1da177e4 LT |
499 | }; |
500 | ||
501 | /* key2index calculation, -1 on invalid index */ | |
bf36b901 AM |
502 | static int sysrq_key_table_key2index(int key) |
503 | { | |
1da177e4 | 504 | int retval; |
bf36b901 AM |
505 | |
506 | if ((key >= '0') && (key <= '9')) | |
1da177e4 | 507 | retval = key - '0'; |
bf36b901 | 508 | else if ((key >= 'a') && (key <= 'z')) |
1da177e4 | 509 | retval = key + 10 - 'a'; |
bf36b901 | 510 | else |
1da177e4 | 511 | retval = -1; |
1da177e4 LT |
512 | return retval; |
513 | } | |
514 | ||
515 | /* | |
516 | * get and put functions for the table, exposed to modules. | |
517 | */ | |
bf36b901 AM |
518 | struct sysrq_key_op *__sysrq_get_key_op(int key) |
519 | { | |
520 | struct sysrq_key_op *op_p = NULL; | |
1da177e4 | 521 | int i; |
bf36b901 | 522 | |
1da177e4 | 523 | i = sysrq_key_table_key2index(key); |
bf36b901 AM |
524 | if (i != -1) |
525 | op_p = sysrq_key_table[i]; | |
97f5f0cd | 526 | |
1da177e4 LT |
527 | return op_p; |
528 | } | |
529 | ||
bf36b901 AM |
530 | static void __sysrq_put_key_op(int key, struct sysrq_key_op *op_p) |
531 | { | |
532 | int i = sysrq_key_table_key2index(key); | |
1da177e4 | 533 | |
1da177e4 LT |
534 | if (i != -1) |
535 | sysrq_key_table[i] = op_p; | |
536 | } | |
537 | ||
f335397d | 538 | void __handle_sysrq(int key, bool check_mask) |
1da177e4 LT |
539 | { |
540 | struct sysrq_key_op *op_p; | |
541 | int orig_log_level; | |
c39ea0b9 | 542 | int orig_suppress_printk; |
bf36b901 | 543 | int i; |
1da177e4 | 544 | |
c39ea0b9 FT |
545 | orig_suppress_printk = suppress_printk; |
546 | suppress_printk = 0; | |
547 | ||
722773af | 548 | rcu_sysrq_start(); |
984d74a7 | 549 | rcu_read_lock(); |
fb144adc AW |
550 | /* |
551 | * Raise the apparent loglevel to maximum so that the sysrq header | |
552 | * is shown to provide the user with positive feedback. We do not | |
553 | * simply emit this at KERN_EMERG as that would change message | |
554 | * routing in the consumers of /proc/kmsg. | |
555 | */ | |
1da177e4 | 556 | orig_log_level = console_loglevel; |
a8fe19eb | 557 | console_loglevel = CONSOLE_LOGLEVEL_DEFAULT; |
1da177e4 LT |
558 | |
559 | op_p = __sysrq_get_key_op(key); | |
560 | if (op_p) { | |
bf36b901 AM |
561 | /* |
562 | * Should we check for enabled operations (/proc/sysrq-trigger | |
563 | * should not) and is the invoked operation enabled? | |
564 | */ | |
5d6f647f | 565 | if (!check_mask || sysrq_on_mask(op_p->enable_mask)) { |
c3fee609 | 566 | pr_info("%s\n", op_p->action_msg); |
1da177e4 | 567 | console_loglevel = orig_log_level; |
1495cc9d | 568 | op_p->handler(key); |
bf36b901 | 569 | } else { |
c3fee609 | 570 | pr_info("This sysrq operation is disabled.\n"); |
075e1a0c | 571 | console_loglevel = orig_log_level; |
bf36b901 | 572 | } |
1da177e4 | 573 | } else { |
c3fee609 | 574 | pr_info("HELP : "); |
1da177e4 | 575 | /* Only print the help msg once per handler */ |
bf36b901 AM |
576 | for (i = 0; i < ARRAY_SIZE(sysrq_key_table); i++) { |
577 | if (sysrq_key_table[i]) { | |
578 | int j; | |
579 | ||
580 | for (j = 0; sysrq_key_table[i] != | |
581 | sysrq_key_table[j]; j++) | |
582 | ; | |
583 | if (j != i) | |
584 | continue; | |
401e4a7c | 585 | pr_cont("%s ", sysrq_key_table[i]->help_msg); |
bf36b901 | 586 | } |
1da177e4 | 587 | } |
401e4a7c | 588 | pr_cont("\n"); |
1da177e4 LT |
589 | console_loglevel = orig_log_level; |
590 | } | |
984d74a7 | 591 | rcu_read_unlock(); |
722773af | 592 | rcu_sysrq_end(); |
c39ea0b9 FT |
593 | |
594 | suppress_printk = orig_suppress_printk; | |
1da177e4 LT |
595 | } |
596 | ||
f335397d | 597 | void handle_sysrq(int key) |
1da177e4 | 598 | { |
5d6f647f | 599 | if (sysrq_on()) |
f335397d | 600 | __handle_sysrq(key, true); |
1da177e4 | 601 | } |
bf36b901 | 602 | EXPORT_SYMBOL(handle_sysrq); |
1da177e4 | 603 | |
97f5f0cd | 604 | #ifdef CONFIG_INPUT |
ffb6e0c9 | 605 | static int sysrq_reset_downtime_ms; |
97f5f0cd DT |
606 | |
607 | /* Simple translation table for the SysRq keys */ | |
fcb71930 | 608 | static const unsigned char sysrq_xlate[KEY_CNT] = |
97f5f0cd DT |
609 | "\000\0331234567890-=\177\t" /* 0x00 - 0x0f */ |
610 | "qwertyuiop[]\r\000as" /* 0x10 - 0x1f */ | |
611 | "dfghjkl;'`\000\\zxcv" /* 0x20 - 0x2f */ | |
612 | "bnm,./\000*\000 \000\201\202\203\204\205" /* 0x30 - 0x3f */ | |
613 | "\206\207\210\211\212\000\000789-456+1" /* 0x40 - 0x4f */ | |
614 | "230\177\000\000\213\214\000\000\000\000\000\000\000\000\000\000" /* 0x50 - 0x5f */ | |
615 | "\r\000/"; /* 0x60 - 0x6f */ | |
616 | ||
fcb71930 DT |
617 | struct sysrq_state { |
618 | struct input_handle handle; | |
619 | struct work_struct reinject_work; | |
620 | unsigned long key_down[BITS_TO_LONGS(KEY_CNT)]; | |
621 | unsigned int alt; | |
622 | unsigned int alt_use; | |
623 | bool active; | |
624 | bool need_reinject; | |
7ab7b5ad | 625 | bool reinjecting; |
154b7a48 MP |
626 | |
627 | /* reset sequence handling */ | |
628 | bool reset_canceled; | |
3d289517 | 629 | bool reset_requested; |
154b7a48 MP |
630 | unsigned long reset_keybit[BITS_TO_LONGS(KEY_CNT)]; |
631 | int reset_seq_len; | |
632 | int reset_seq_cnt; | |
633 | int reset_seq_version; | |
39030786 | 634 | struct timer_list keyreset_timer; |
fcb71930 DT |
635 | }; |
636 | ||
154b7a48 MP |
637 | #define SYSRQ_KEY_RESET_MAX 20 /* Should be plenty */ |
638 | static unsigned short sysrq_reset_seq[SYSRQ_KEY_RESET_MAX]; | |
639 | static unsigned int sysrq_reset_seq_len; | |
640 | static unsigned int sysrq_reset_seq_version = 1; | |
641 | ||
642 | static void sysrq_parse_reset_sequence(struct sysrq_state *state) | |
643 | { | |
644 | int i; | |
645 | unsigned short key; | |
646 | ||
647 | state->reset_seq_cnt = 0; | |
648 | ||
649 | for (i = 0; i < sysrq_reset_seq_len; i++) { | |
650 | key = sysrq_reset_seq[i]; | |
651 | ||
652 | if (key == KEY_RESERVED || key > KEY_MAX) | |
653 | break; | |
654 | ||
655 | __set_bit(key, state->reset_keybit); | |
656 | state->reset_seq_len++; | |
657 | ||
658 | if (test_bit(key, state->key_down)) | |
659 | state->reset_seq_cnt++; | |
660 | } | |
661 | ||
662 | /* Disable reset until old keys are not released */ | |
663 | state->reset_canceled = state->reset_seq_cnt != 0; | |
664 | ||
665 | state->reset_seq_version = sysrq_reset_seq_version; | |
666 | } | |
667 | ||
8c318fa9 | 668 | static void sysrq_do_reset(struct timer_list *t) |
39030786 | 669 | { |
8c318fa9 | 670 | struct sysrq_state *state = from_timer(state, t, keyreset_timer); |
3d289517 MP |
671 | |
672 | state->reset_requested = true; | |
673 | ||
8fefbc6d | 674 | orderly_reboot(); |
39030786 MP |
675 | } |
676 | ||
677 | static void sysrq_handle_reset_request(struct sysrq_state *state) | |
678 | { | |
3d289517 MP |
679 | if (state->reset_requested) |
680 | __handle_sysrq(sysrq_xlate[KEY_B], false); | |
681 | ||
39030786 MP |
682 | if (sysrq_reset_downtime_ms) |
683 | mod_timer(&state->keyreset_timer, | |
684 | jiffies + msecs_to_jiffies(sysrq_reset_downtime_ms)); | |
685 | else | |
8c318fa9 | 686 | sysrq_do_reset(&state->keyreset_timer); |
39030786 MP |
687 | } |
688 | ||
689 | static void sysrq_detect_reset_sequence(struct sysrq_state *state, | |
154b7a48 MP |
690 | unsigned int code, int value) |
691 | { | |
692 | if (!test_bit(code, state->reset_keybit)) { | |
693 | /* | |
694 | * Pressing any key _not_ in reset sequence cancels | |
39030786 MP |
695 | * the reset sequence. Also cancelling the timer in |
696 | * case additional keys were pressed after a reset | |
697 | * has been requested. | |
154b7a48 | 698 | */ |
39030786 | 699 | if (value && state->reset_seq_cnt) { |
154b7a48 | 700 | state->reset_canceled = true; |
39030786 MP |
701 | del_timer(&state->keyreset_timer); |
702 | } | |
154b7a48 | 703 | } else if (value == 0) { |
39030786 MP |
704 | /* |
705 | * Key release - all keys in the reset sequence need | |
706 | * to be pressed and held for the reset timeout | |
707 | * to hold. | |
708 | */ | |
709 | del_timer(&state->keyreset_timer); | |
710 | ||
154b7a48 MP |
711 | if (--state->reset_seq_cnt == 0) |
712 | state->reset_canceled = false; | |
713 | } else if (value == 1) { | |
714 | /* key press, not autorepeat */ | |
715 | if (++state->reset_seq_cnt == state->reset_seq_len && | |
716 | !state->reset_canceled) { | |
39030786 | 717 | sysrq_handle_reset_request(state); |
154b7a48 MP |
718 | } |
719 | } | |
154b7a48 MP |
720 | } |
721 | ||
4c076eb0 MP |
722 | #ifdef CONFIG_OF |
723 | static void sysrq_of_get_keyreset_config(void) | |
724 | { | |
725 | u32 key; | |
726 | struct device_node *np; | |
727 | struct property *prop; | |
728 | const __be32 *p; | |
729 | ||
730 | np = of_find_node_by_path("/chosen/linux,sysrq-reset-seq"); | |
731 | if (!np) { | |
732 | pr_debug("No sysrq node found"); | |
733 | return; | |
734 | } | |
735 | ||
736 | /* Reset in case a __weak definition was present */ | |
737 | sysrq_reset_seq_len = 0; | |
738 | ||
739 | of_property_for_each_u32(np, "keyset", prop, p, key) { | |
740 | if (key == KEY_RESERVED || key > KEY_MAX || | |
741 | sysrq_reset_seq_len == SYSRQ_KEY_RESET_MAX) | |
742 | break; | |
743 | ||
744 | sysrq_reset_seq[sysrq_reset_seq_len++] = (unsigned short)key; | |
745 | } | |
746 | ||
747 | /* Get reset timeout if any. */ | |
748 | of_property_read_u32(np, "timeout-ms", &sysrq_reset_downtime_ms); | |
279070b9 YL |
749 | |
750 | of_node_put(np); | |
4c076eb0 MP |
751 | } |
752 | #else | |
753 | static void sysrq_of_get_keyreset_config(void) | |
754 | { | |
755 | } | |
756 | #endif | |
757 | ||
fcb71930 DT |
758 | static void sysrq_reinject_alt_sysrq(struct work_struct *work) |
759 | { | |
760 | struct sysrq_state *sysrq = | |
761 | container_of(work, struct sysrq_state, reinject_work); | |
762 | struct input_handle *handle = &sysrq->handle; | |
763 | unsigned int alt_code = sysrq->alt_use; | |
764 | ||
765 | if (sysrq->need_reinject) { | |
7ab7b5ad DT |
766 | /* we do not want the assignment to be reordered */ |
767 | sysrq->reinjecting = true; | |
768 | mb(); | |
769 | ||
fcb71930 DT |
770 | /* Simulate press and release of Alt + SysRq */ |
771 | input_inject_event(handle, EV_KEY, alt_code, 1); | |
772 | input_inject_event(handle, EV_KEY, KEY_SYSRQ, 1); | |
773 | input_inject_event(handle, EV_SYN, SYN_REPORT, 1); | |
774 | ||
775 | input_inject_event(handle, EV_KEY, KEY_SYSRQ, 0); | |
776 | input_inject_event(handle, EV_KEY, alt_code, 0); | |
777 | input_inject_event(handle, EV_SYN, SYN_REPORT, 1); | |
7ab7b5ad DT |
778 | |
779 | mb(); | |
780 | sysrq->reinjecting = false; | |
fcb71930 DT |
781 | } |
782 | } | |
97f5f0cd | 783 | |
154b7a48 MP |
784 | static bool sysrq_handle_keypress(struct sysrq_state *sysrq, |
785 | unsigned int code, int value) | |
97f5f0cd | 786 | { |
fcb71930 | 787 | bool was_active = sysrq->active; |
1966cb22 DT |
788 | bool suppress; |
789 | ||
154b7a48 | 790 | switch (code) { |
7ab7b5ad | 791 | |
154b7a48 MP |
792 | case KEY_LEFTALT: |
793 | case KEY_RIGHTALT: | |
794 | if (!value) { | |
795 | /* One of ALTs is being released */ | |
796 | if (sysrq->active && code == sysrq->alt_use) | |
797 | sysrq->active = false; | |
1966cb22 | 798 | |
154b7a48 MP |
799 | sysrq->alt = KEY_RESERVED; |
800 | ||
801 | } else if (value != 2) { | |
802 | sysrq->alt = code; | |
803 | sysrq->need_reinject = false; | |
804 | } | |
fcb71930 | 805 | break; |
97f5f0cd | 806 | |
154b7a48 MP |
807 | case KEY_SYSRQ: |
808 | if (value == 1 && sysrq->alt != KEY_RESERVED) { | |
809 | sysrq->active = true; | |
810 | sysrq->alt_use = sysrq->alt; | |
811 | /* | |
812 | * If nothing else will be pressed we'll need | |
813 | * to re-inject Alt-SysRq keysroke. | |
814 | */ | |
815 | sysrq->need_reinject = true; | |
816 | } | |
97f5f0cd | 817 | |
154b7a48 MP |
818 | /* |
819 | * Pretend that sysrq was never pressed at all. This | |
820 | * is needed to properly handle KGDB which will try | |
821 | * to release all keys after exiting debugger. If we | |
822 | * do not clear key bit it KGDB will end up sending | |
823 | * release events for Alt and SysRq, potentially | |
824 | * triggering print screen function. | |
825 | */ | |
826 | if (sysrq->active) | |
827 | clear_bit(KEY_SYSRQ, sysrq->handle.dev->key); | |
f5dec511 | 828 | |
154b7a48 | 829 | break; |
fcb71930 | 830 | |
154b7a48 MP |
831 | default: |
832 | if (sysrq->active && value && value != 2) { | |
833 | sysrq->need_reinject = false; | |
834 | __handle_sysrq(sysrq_xlate[code], true); | |
835 | } | |
836 | break; | |
837 | } | |
fcb71930 | 838 | |
154b7a48 | 839 | suppress = sysrq->active; |
fcb71930 | 840 | |
154b7a48 | 841 | if (!sysrq->active) { |
fcb71930 | 842 | |
154b7a48 MP |
843 | /* |
844 | * See if reset sequence has changed since the last time. | |
845 | */ | |
846 | if (sysrq->reset_seq_version != sysrq_reset_seq_version) | |
847 | sysrq_parse_reset_sequence(sysrq); | |
fcb71930 | 848 | |
154b7a48 MP |
849 | /* |
850 | * If we are not suppressing key presses keep track of | |
851 | * keyboard state so we can release keys that have been | |
852 | * pressed before entering SysRq mode. | |
853 | */ | |
854 | if (value) | |
855 | set_bit(code, sysrq->key_down); | |
856 | else | |
857 | clear_bit(code, sysrq->key_down); | |
858 | ||
859 | if (was_active) | |
860 | schedule_work(&sysrq->reinject_work); | |
861 | ||
39030786 MP |
862 | /* Check for reset sequence */ |
863 | sysrq_detect_reset_sequence(sysrq, code, value); | |
97f5f0cd | 864 | |
154b7a48 MP |
865 | } else if (value == 0 && test_and_clear_bit(code, sysrq->key_down)) { |
866 | /* | |
867 | * Pass on release events for keys that was pressed before | |
868 | * entering SysRq mode. | |
869 | */ | |
870 | suppress = false; | |
871 | } | |
fcb71930 | 872 | |
154b7a48 MP |
873 | return suppress; |
874 | } | |
fcb71930 | 875 | |
154b7a48 MP |
876 | static bool sysrq_filter(struct input_handle *handle, |
877 | unsigned int type, unsigned int code, int value) | |
878 | { | |
879 | struct sysrq_state *sysrq = handle->private; | |
880 | bool suppress; | |
fcb71930 | 881 | |
154b7a48 MP |
882 | /* |
883 | * Do not filter anything if we are in the process of re-injecting | |
884 | * Alt+SysRq combination. | |
885 | */ | |
886 | if (sysrq->reinjecting) | |
887 | return false; | |
888 | ||
889 | switch (type) { | |
890 | ||
891 | case EV_SYN: | |
892 | suppress = false; | |
893 | break; | |
894 | ||
895 | case EV_KEY: | |
896 | suppress = sysrq_handle_keypress(sysrq, code, value); | |
97f5f0cd DT |
897 | break; |
898 | ||
899 | default: | |
fcb71930 | 900 | suppress = sysrq->active; |
97f5f0cd DT |
901 | break; |
902 | } | |
903 | ||
1966cb22 | 904 | return suppress; |
97f5f0cd DT |
905 | } |
906 | ||
907 | static int sysrq_connect(struct input_handler *handler, | |
908 | struct input_dev *dev, | |
909 | const struct input_device_id *id) | |
910 | { | |
fcb71930 | 911 | struct sysrq_state *sysrq; |
97f5f0cd DT |
912 | int error; |
913 | ||
fcb71930 DT |
914 | sysrq = kzalloc(sizeof(struct sysrq_state), GFP_KERNEL); |
915 | if (!sysrq) | |
97f5f0cd DT |
916 | return -ENOMEM; |
917 | ||
fcb71930 DT |
918 | INIT_WORK(&sysrq->reinject_work, sysrq_reinject_alt_sysrq); |
919 | ||
920 | sysrq->handle.dev = dev; | |
921 | sysrq->handle.handler = handler; | |
922 | sysrq->handle.name = "sysrq"; | |
923 | sysrq->handle.private = sysrq; | |
8c318fa9 | 924 | timer_setup(&sysrq->keyreset_timer, sysrq_do_reset, 0); |
97f5f0cd | 925 | |
fcb71930 | 926 | error = input_register_handle(&sysrq->handle); |
97f5f0cd DT |
927 | if (error) { |
928 | pr_err("Failed to register input sysrq handler, error %d\n", | |
929 | error); | |
930 | goto err_free; | |
931 | } | |
932 | ||
fcb71930 | 933 | error = input_open_device(&sysrq->handle); |
97f5f0cd DT |
934 | if (error) { |
935 | pr_err("Failed to open input device, error %d\n", error); | |
936 | goto err_unregister; | |
937 | } | |
938 | ||
939 | return 0; | |
940 | ||
941 | err_unregister: | |
fcb71930 | 942 | input_unregister_handle(&sysrq->handle); |
97f5f0cd | 943 | err_free: |
fcb71930 | 944 | kfree(sysrq); |
97f5f0cd DT |
945 | return error; |
946 | } | |
947 | ||
948 | static void sysrq_disconnect(struct input_handle *handle) | |
949 | { | |
fcb71930 DT |
950 | struct sysrq_state *sysrq = handle->private; |
951 | ||
97f5f0cd | 952 | input_close_device(handle); |
fcb71930 | 953 | cancel_work_sync(&sysrq->reinject_work); |
39030786 | 954 | del_timer_sync(&sysrq->keyreset_timer); |
97f5f0cd | 955 | input_unregister_handle(handle); |
fcb71930 | 956 | kfree(sysrq); |
97f5f0cd DT |
957 | } |
958 | ||
959 | /* | |
1966cb22 DT |
960 | * We are matching on KEY_LEFTALT instead of KEY_SYSRQ because not all |
961 | * keyboards have SysRq key predefined and so user may add it to keymap | |
97f5f0cd DT |
962 | * later, but we expect all such keyboards to have left alt. |
963 | */ | |
964 | static const struct input_device_id sysrq_ids[] = { | |
965 | { | |
966 | .flags = INPUT_DEVICE_ID_MATCH_EVBIT | | |
967 | INPUT_DEVICE_ID_MATCH_KEYBIT, | |
802c0388 AM |
968 | .evbit = { [BIT_WORD(EV_KEY)] = BIT_MASK(EV_KEY) }, |
969 | .keybit = { [BIT_WORD(KEY_LEFTALT)] = BIT_MASK(KEY_LEFTALT) }, | |
97f5f0cd DT |
970 | }, |
971 | { }, | |
972 | }; | |
973 | ||
974 | static struct input_handler sysrq_handler = { | |
975 | .filter = sysrq_filter, | |
976 | .connect = sysrq_connect, | |
977 | .disconnect = sysrq_disconnect, | |
978 | .name = "sysrq", | |
979 | .id_table = sysrq_ids, | |
980 | }; | |
981 | ||
97f5f0cd DT |
982 | static inline void sysrq_register_handler(void) |
983 | { | |
984 | int error; | |
985 | ||
4c076eb0 MP |
986 | sysrq_of_get_keyreset_config(); |
987 | ||
97f5f0cd DT |
988 | error = input_register_handler(&sysrq_handler); |
989 | if (error) | |
990 | pr_err("Failed to register input handler, error %d", error); | |
97f5f0cd DT |
991 | } |
992 | ||
993 | static inline void sysrq_unregister_handler(void) | |
994 | { | |
f06327d1 | 995 | input_unregister_handler(&sysrq_handler); |
97f5f0cd DT |
996 | } |
997 | ||
154b7a48 MP |
998 | static int sysrq_reset_seq_param_set(const char *buffer, |
999 | const struct kernel_param *kp) | |
1000 | { | |
1001 | unsigned long val; | |
1002 | int error; | |
1003 | ||
86b40567 | 1004 | error = kstrtoul(buffer, 0, &val); |
154b7a48 MP |
1005 | if (error < 0) |
1006 | return error; | |
1007 | ||
1008 | if (val > KEY_MAX) | |
1009 | return -EINVAL; | |
1010 | ||
1011 | *((unsigned short *)kp->arg) = val; | |
1012 | sysrq_reset_seq_version++; | |
1013 | ||
1014 | return 0; | |
1015 | } | |
1016 | ||
9c27847d | 1017 | static const struct kernel_param_ops param_ops_sysrq_reset_seq = { |
154b7a48 MP |
1018 | .get = param_get_ushort, |
1019 | .set = sysrq_reset_seq_param_set, | |
1020 | }; | |
1021 | ||
1022 | #define param_check_sysrq_reset_seq(name, p) \ | |
1023 | __param_check(name, p, unsigned short) | |
1024 | ||
3bce6f64 PG |
1025 | /* |
1026 | * not really modular, but the easiest way to keep compat with existing | |
1027 | * bootargs behaviour is to continue using module_param here. | |
1028 | */ | |
154b7a48 MP |
1029 | module_param_array_named(reset_seq, sysrq_reset_seq, sysrq_reset_seq, |
1030 | &sysrq_reset_seq_len, 0644); | |
1031 | ||
39030786 MP |
1032 | module_param_named(sysrq_downtime_ms, sysrq_reset_downtime_ms, int, 0644); |
1033 | ||
97f5f0cd DT |
1034 | #else |
1035 | ||
1036 | static inline void sysrq_register_handler(void) | |
1037 | { | |
1038 | } | |
1039 | ||
1040 | static inline void sysrq_unregister_handler(void) | |
1041 | { | |
1042 | } | |
1043 | ||
1044 | #endif /* CONFIG_INPUT */ | |
1045 | ||
1046 | int sysrq_toggle_support(int enable_mask) | |
1047 | { | |
1048 | bool was_enabled = sysrq_on(); | |
1049 | ||
1050 | sysrq_enabled = enable_mask; | |
1051 | ||
1052 | if (was_enabled != sysrq_on()) { | |
1053 | if (sysrq_on()) | |
1054 | sysrq_register_handler(); | |
1055 | else | |
1056 | sysrq_unregister_handler(); | |
1057 | } | |
1058 | ||
1059 | return 0; | |
1060 | } | |
1061 | ||
cf62ddce | 1062 | static int __sysrq_swap_key_ops(int key, struct sysrq_key_op *insert_op_p, |
bf36b901 AM |
1063 | struct sysrq_key_op *remove_op_p) |
1064 | { | |
1da177e4 | 1065 | int retval; |
1da177e4 | 1066 | |
984d74a7 | 1067 | spin_lock(&sysrq_key_table_lock); |
1da177e4 LT |
1068 | if (__sysrq_get_key_op(key) == remove_op_p) { |
1069 | __sysrq_put_key_op(key, insert_op_p); | |
1070 | retval = 0; | |
1071 | } else { | |
1072 | retval = -1; | |
1073 | } | |
984d74a7 RR |
1074 | spin_unlock(&sysrq_key_table_lock); |
1075 | ||
1076 | /* | |
1077 | * A concurrent __handle_sysrq either got the old op or the new op. | |
1078 | * Wait for it to go away before returning, so the code for an old | |
1079 | * op is not freed (eg. on module unload) while it is in use. | |
1080 | */ | |
1081 | synchronize_rcu(); | |
1082 | ||
1da177e4 LT |
1083 | return retval; |
1084 | } | |
1085 | ||
1086 | int register_sysrq_key(int key, struct sysrq_key_op *op_p) | |
1087 | { | |
1088 | return __sysrq_swap_key_ops(key, op_p, NULL); | |
1089 | } | |
bf36b901 | 1090 | EXPORT_SYMBOL(register_sysrq_key); |
1da177e4 LT |
1091 | |
1092 | int unregister_sysrq_key(int key, struct sysrq_key_op *op_p) | |
1093 | { | |
1094 | return __sysrq_swap_key_ops(key, NULL, op_p); | |
1095 | } | |
1da177e4 | 1096 | EXPORT_SYMBOL(unregister_sysrq_key); |
f40cbaa5 AD |
1097 | |
1098 | #ifdef CONFIG_PROC_FS | |
1099 | /* | |
1100 | * writing 'C' to /proc/sysrq-trigger is like sysrq-C | |
1101 | */ | |
1102 | static ssize_t write_sysrq_trigger(struct file *file, const char __user *buf, | |
1103 | size_t count, loff_t *ppos) | |
1104 | { | |
1105 | if (count) { | |
1106 | char c; | |
1107 | ||
1108 | if (get_user(c, buf)) | |
1109 | return -EFAULT; | |
f335397d | 1110 | __handle_sysrq(c, false); |
f40cbaa5 | 1111 | } |
97f5f0cd | 1112 | |
f40cbaa5 AD |
1113 | return count; |
1114 | } | |
1115 | ||
97a32539 AD |
1116 | static const struct proc_ops sysrq_trigger_proc_ops = { |
1117 | .proc_write = write_sysrq_trigger, | |
1118 | .proc_lseek = noop_llseek, | |
f40cbaa5 AD |
1119 | }; |
1120 | ||
97f5f0cd DT |
1121 | static void sysrq_init_procfs(void) |
1122 | { | |
1123 | if (!proc_create("sysrq-trigger", S_IWUSR, NULL, | |
97a32539 | 1124 | &sysrq_trigger_proc_ops)) |
97f5f0cd DT |
1125 | pr_err("Failed to register proc interface\n"); |
1126 | } | |
1127 | ||
1128 | #else | |
1129 | ||
1130 | static inline void sysrq_init_procfs(void) | |
1131 | { | |
1132 | } | |
1133 | ||
1134 | #endif /* CONFIG_PROC_FS */ | |
1135 | ||
f40cbaa5 AD |
1136 | static int __init sysrq_init(void) |
1137 | { | |
97f5f0cd DT |
1138 | sysrq_init_procfs(); |
1139 | ||
1140 | if (sysrq_on()) | |
1141 | sysrq_register_handler(); | |
1142 | ||
f40cbaa5 AD |
1143 | return 0; |
1144 | } | |
3bce6f64 | 1145 | device_initcall(sysrq_init); |