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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 */ |
d346cce3 | 483 | NULL, /* x */ |
93dae5b7 | 484 | /* y: May be registered on sparc64 for global register dump */ |
bf36b901 | 485 | NULL, /* y */ |
69f698ad | 486 | &sysrq_ftrace_dump_op, /* z */ |
1da177e4 LT |
487 | }; |
488 | ||
489 | /* key2index calculation, -1 on invalid index */ | |
bf36b901 AM |
490 | static int sysrq_key_table_key2index(int key) |
491 | { | |
1da177e4 | 492 | int retval; |
bf36b901 AM |
493 | |
494 | if ((key >= '0') && (key <= '9')) | |
1da177e4 | 495 | retval = key - '0'; |
bf36b901 | 496 | else if ((key >= 'a') && (key <= 'z')) |
1da177e4 | 497 | retval = key + 10 - 'a'; |
bf36b901 | 498 | else |
1da177e4 | 499 | retval = -1; |
1da177e4 LT |
500 | return retval; |
501 | } | |
502 | ||
503 | /* | |
504 | * get and put functions for the table, exposed to modules. | |
505 | */ | |
bf36b901 AM |
506 | struct sysrq_key_op *__sysrq_get_key_op(int key) |
507 | { | |
508 | struct sysrq_key_op *op_p = NULL; | |
1da177e4 | 509 | int i; |
bf36b901 | 510 | |
1da177e4 | 511 | i = sysrq_key_table_key2index(key); |
bf36b901 AM |
512 | if (i != -1) |
513 | op_p = sysrq_key_table[i]; | |
97f5f0cd | 514 | |
1da177e4 LT |
515 | return op_p; |
516 | } | |
517 | ||
bf36b901 AM |
518 | static void __sysrq_put_key_op(int key, struct sysrq_key_op *op_p) |
519 | { | |
520 | int i = sysrq_key_table_key2index(key); | |
1da177e4 | 521 | |
1da177e4 LT |
522 | if (i != -1) |
523 | sysrq_key_table[i] = op_p; | |
524 | } | |
525 | ||
f335397d | 526 | void __handle_sysrq(int key, bool check_mask) |
1da177e4 LT |
527 | { |
528 | struct sysrq_key_op *op_p; | |
529 | int orig_log_level; | |
bf36b901 | 530 | int i; |
1da177e4 | 531 | |
722773af | 532 | rcu_sysrq_start(); |
984d74a7 | 533 | rcu_read_lock(); |
fb144adc AW |
534 | /* |
535 | * Raise the apparent loglevel to maximum so that the sysrq header | |
536 | * is shown to provide the user with positive feedback. We do not | |
537 | * simply emit this at KERN_EMERG as that would change message | |
538 | * routing in the consumers of /proc/kmsg. | |
539 | */ | |
1da177e4 | 540 | orig_log_level = console_loglevel; |
a8fe19eb | 541 | console_loglevel = CONSOLE_LOGLEVEL_DEFAULT; |
1da177e4 LT |
542 | |
543 | op_p = __sysrq_get_key_op(key); | |
544 | if (op_p) { | |
bf36b901 AM |
545 | /* |
546 | * Should we check for enabled operations (/proc/sysrq-trigger | |
547 | * should not) and is the invoked operation enabled? | |
548 | */ | |
5d6f647f | 549 | if (!check_mask || sysrq_on_mask(op_p->enable_mask)) { |
c3fee609 | 550 | pr_info("%s\n", op_p->action_msg); |
1da177e4 | 551 | console_loglevel = orig_log_level; |
1495cc9d | 552 | op_p->handler(key); |
bf36b901 | 553 | } else { |
c3fee609 | 554 | pr_info("This sysrq operation is disabled.\n"); |
075e1a0c | 555 | console_loglevel = orig_log_level; |
bf36b901 | 556 | } |
1da177e4 | 557 | } else { |
c3fee609 | 558 | pr_info("HELP : "); |
1da177e4 | 559 | /* Only print the help msg once per handler */ |
bf36b901 AM |
560 | for (i = 0; i < ARRAY_SIZE(sysrq_key_table); i++) { |
561 | if (sysrq_key_table[i]) { | |
562 | int j; | |
563 | ||
564 | for (j = 0; sysrq_key_table[i] != | |
565 | sysrq_key_table[j]; j++) | |
566 | ; | |
567 | if (j != i) | |
568 | continue; | |
401e4a7c | 569 | pr_cont("%s ", sysrq_key_table[i]->help_msg); |
bf36b901 | 570 | } |
1da177e4 | 571 | } |
401e4a7c | 572 | pr_cont("\n"); |
1da177e4 LT |
573 | console_loglevel = orig_log_level; |
574 | } | |
984d74a7 | 575 | rcu_read_unlock(); |
722773af | 576 | rcu_sysrq_end(); |
1da177e4 LT |
577 | } |
578 | ||
f335397d | 579 | void handle_sysrq(int key) |
1da177e4 | 580 | { |
5d6f647f | 581 | if (sysrq_on()) |
f335397d | 582 | __handle_sysrq(key, true); |
1da177e4 | 583 | } |
bf36b901 | 584 | EXPORT_SYMBOL(handle_sysrq); |
1da177e4 | 585 | |
97f5f0cd | 586 | #ifdef CONFIG_INPUT |
ffb6e0c9 | 587 | static int sysrq_reset_downtime_ms; |
97f5f0cd DT |
588 | |
589 | /* Simple translation table for the SysRq keys */ | |
fcb71930 | 590 | static const unsigned char sysrq_xlate[KEY_CNT] = |
97f5f0cd DT |
591 | "\000\0331234567890-=\177\t" /* 0x00 - 0x0f */ |
592 | "qwertyuiop[]\r\000as" /* 0x10 - 0x1f */ | |
593 | "dfghjkl;'`\000\\zxcv" /* 0x20 - 0x2f */ | |
594 | "bnm,./\000*\000 \000\201\202\203\204\205" /* 0x30 - 0x3f */ | |
595 | "\206\207\210\211\212\000\000789-456+1" /* 0x40 - 0x4f */ | |
596 | "230\177\000\000\213\214\000\000\000\000\000\000\000\000\000\000" /* 0x50 - 0x5f */ | |
597 | "\r\000/"; /* 0x60 - 0x6f */ | |
598 | ||
fcb71930 DT |
599 | struct sysrq_state { |
600 | struct input_handle handle; | |
601 | struct work_struct reinject_work; | |
602 | unsigned long key_down[BITS_TO_LONGS(KEY_CNT)]; | |
603 | unsigned int alt; | |
604 | unsigned int alt_use; | |
605 | bool active; | |
606 | bool need_reinject; | |
7ab7b5ad | 607 | bool reinjecting; |
154b7a48 MP |
608 | |
609 | /* reset sequence handling */ | |
610 | bool reset_canceled; | |
3d289517 | 611 | bool reset_requested; |
154b7a48 MP |
612 | unsigned long reset_keybit[BITS_TO_LONGS(KEY_CNT)]; |
613 | int reset_seq_len; | |
614 | int reset_seq_cnt; | |
615 | int reset_seq_version; | |
39030786 | 616 | struct timer_list keyreset_timer; |
fcb71930 DT |
617 | }; |
618 | ||
154b7a48 MP |
619 | #define SYSRQ_KEY_RESET_MAX 20 /* Should be plenty */ |
620 | static unsigned short sysrq_reset_seq[SYSRQ_KEY_RESET_MAX]; | |
621 | static unsigned int sysrq_reset_seq_len; | |
622 | static unsigned int sysrq_reset_seq_version = 1; | |
623 | ||
624 | static void sysrq_parse_reset_sequence(struct sysrq_state *state) | |
625 | { | |
626 | int i; | |
627 | unsigned short key; | |
628 | ||
629 | state->reset_seq_cnt = 0; | |
630 | ||
631 | for (i = 0; i < sysrq_reset_seq_len; i++) { | |
632 | key = sysrq_reset_seq[i]; | |
633 | ||
634 | if (key == KEY_RESERVED || key > KEY_MAX) | |
635 | break; | |
636 | ||
637 | __set_bit(key, state->reset_keybit); | |
638 | state->reset_seq_len++; | |
639 | ||
640 | if (test_bit(key, state->key_down)) | |
641 | state->reset_seq_cnt++; | |
642 | } | |
643 | ||
644 | /* Disable reset until old keys are not released */ | |
645 | state->reset_canceled = state->reset_seq_cnt != 0; | |
646 | ||
647 | state->reset_seq_version = sysrq_reset_seq_version; | |
648 | } | |
649 | ||
8c318fa9 | 650 | static void sysrq_do_reset(struct timer_list *t) |
39030786 | 651 | { |
8c318fa9 | 652 | struct sysrq_state *state = from_timer(state, t, keyreset_timer); |
3d289517 MP |
653 | |
654 | state->reset_requested = true; | |
655 | ||
8fefbc6d | 656 | orderly_reboot(); |
39030786 MP |
657 | } |
658 | ||
659 | static void sysrq_handle_reset_request(struct sysrq_state *state) | |
660 | { | |
3d289517 MP |
661 | if (state->reset_requested) |
662 | __handle_sysrq(sysrq_xlate[KEY_B], false); | |
663 | ||
39030786 MP |
664 | if (sysrq_reset_downtime_ms) |
665 | mod_timer(&state->keyreset_timer, | |
666 | jiffies + msecs_to_jiffies(sysrq_reset_downtime_ms)); | |
667 | else | |
8c318fa9 | 668 | sysrq_do_reset(&state->keyreset_timer); |
39030786 MP |
669 | } |
670 | ||
671 | static void sysrq_detect_reset_sequence(struct sysrq_state *state, | |
154b7a48 MP |
672 | unsigned int code, int value) |
673 | { | |
674 | if (!test_bit(code, state->reset_keybit)) { | |
675 | /* | |
676 | * Pressing any key _not_ in reset sequence cancels | |
39030786 MP |
677 | * the reset sequence. Also cancelling the timer in |
678 | * case additional keys were pressed after a reset | |
679 | * has been requested. | |
154b7a48 | 680 | */ |
39030786 | 681 | if (value && state->reset_seq_cnt) { |
154b7a48 | 682 | state->reset_canceled = true; |
39030786 MP |
683 | del_timer(&state->keyreset_timer); |
684 | } | |
154b7a48 | 685 | } else if (value == 0) { |
39030786 MP |
686 | /* |
687 | * Key release - all keys in the reset sequence need | |
688 | * to be pressed and held for the reset timeout | |
689 | * to hold. | |
690 | */ | |
691 | del_timer(&state->keyreset_timer); | |
692 | ||
154b7a48 MP |
693 | if (--state->reset_seq_cnt == 0) |
694 | state->reset_canceled = false; | |
695 | } else if (value == 1) { | |
696 | /* key press, not autorepeat */ | |
697 | if (++state->reset_seq_cnt == state->reset_seq_len && | |
698 | !state->reset_canceled) { | |
39030786 | 699 | sysrq_handle_reset_request(state); |
154b7a48 MP |
700 | } |
701 | } | |
154b7a48 MP |
702 | } |
703 | ||
4c076eb0 MP |
704 | #ifdef CONFIG_OF |
705 | static void sysrq_of_get_keyreset_config(void) | |
706 | { | |
707 | u32 key; | |
708 | struct device_node *np; | |
709 | struct property *prop; | |
710 | const __be32 *p; | |
711 | ||
712 | np = of_find_node_by_path("/chosen/linux,sysrq-reset-seq"); | |
713 | if (!np) { | |
714 | pr_debug("No sysrq node found"); | |
715 | return; | |
716 | } | |
717 | ||
718 | /* Reset in case a __weak definition was present */ | |
719 | sysrq_reset_seq_len = 0; | |
720 | ||
721 | of_property_for_each_u32(np, "keyset", prop, p, key) { | |
722 | if (key == KEY_RESERVED || key > KEY_MAX || | |
723 | sysrq_reset_seq_len == SYSRQ_KEY_RESET_MAX) | |
724 | break; | |
725 | ||
726 | sysrq_reset_seq[sysrq_reset_seq_len++] = (unsigned short)key; | |
727 | } | |
728 | ||
729 | /* Get reset timeout if any. */ | |
730 | of_property_read_u32(np, "timeout-ms", &sysrq_reset_downtime_ms); | |
279070b9 YL |
731 | |
732 | of_node_put(np); | |
4c076eb0 MP |
733 | } |
734 | #else | |
735 | static void sysrq_of_get_keyreset_config(void) | |
736 | { | |
737 | } | |
738 | #endif | |
739 | ||
fcb71930 DT |
740 | static void sysrq_reinject_alt_sysrq(struct work_struct *work) |
741 | { | |
742 | struct sysrq_state *sysrq = | |
743 | container_of(work, struct sysrq_state, reinject_work); | |
744 | struct input_handle *handle = &sysrq->handle; | |
745 | unsigned int alt_code = sysrq->alt_use; | |
746 | ||
747 | if (sysrq->need_reinject) { | |
7ab7b5ad DT |
748 | /* we do not want the assignment to be reordered */ |
749 | sysrq->reinjecting = true; | |
750 | mb(); | |
751 | ||
fcb71930 DT |
752 | /* Simulate press and release of Alt + SysRq */ |
753 | input_inject_event(handle, EV_KEY, alt_code, 1); | |
754 | input_inject_event(handle, EV_KEY, KEY_SYSRQ, 1); | |
755 | input_inject_event(handle, EV_SYN, SYN_REPORT, 1); | |
756 | ||
757 | input_inject_event(handle, EV_KEY, KEY_SYSRQ, 0); | |
758 | input_inject_event(handle, EV_KEY, alt_code, 0); | |
759 | input_inject_event(handle, EV_SYN, SYN_REPORT, 1); | |
7ab7b5ad DT |
760 | |
761 | mb(); | |
762 | sysrq->reinjecting = false; | |
fcb71930 DT |
763 | } |
764 | } | |
97f5f0cd | 765 | |
154b7a48 MP |
766 | static bool sysrq_handle_keypress(struct sysrq_state *sysrq, |
767 | unsigned int code, int value) | |
97f5f0cd | 768 | { |
fcb71930 | 769 | bool was_active = sysrq->active; |
1966cb22 DT |
770 | bool suppress; |
771 | ||
154b7a48 | 772 | switch (code) { |
7ab7b5ad | 773 | |
154b7a48 MP |
774 | case KEY_LEFTALT: |
775 | case KEY_RIGHTALT: | |
776 | if (!value) { | |
777 | /* One of ALTs is being released */ | |
778 | if (sysrq->active && code == sysrq->alt_use) | |
779 | sysrq->active = false; | |
1966cb22 | 780 | |
154b7a48 MP |
781 | sysrq->alt = KEY_RESERVED; |
782 | ||
783 | } else if (value != 2) { | |
784 | sysrq->alt = code; | |
785 | sysrq->need_reinject = false; | |
786 | } | |
fcb71930 | 787 | break; |
97f5f0cd | 788 | |
154b7a48 MP |
789 | case KEY_SYSRQ: |
790 | if (value == 1 && sysrq->alt != KEY_RESERVED) { | |
791 | sysrq->active = true; | |
792 | sysrq->alt_use = sysrq->alt; | |
793 | /* | |
794 | * If nothing else will be pressed we'll need | |
795 | * to re-inject Alt-SysRq keysroke. | |
796 | */ | |
797 | sysrq->need_reinject = true; | |
798 | } | |
97f5f0cd | 799 | |
154b7a48 MP |
800 | /* |
801 | * Pretend that sysrq was never pressed at all. This | |
802 | * is needed to properly handle KGDB which will try | |
803 | * to release all keys after exiting debugger. If we | |
804 | * do not clear key bit it KGDB will end up sending | |
805 | * release events for Alt and SysRq, potentially | |
806 | * triggering print screen function. | |
807 | */ | |
808 | if (sysrq->active) | |
809 | clear_bit(KEY_SYSRQ, sysrq->handle.dev->key); | |
f5dec511 | 810 | |
154b7a48 | 811 | break; |
fcb71930 | 812 | |
154b7a48 MP |
813 | default: |
814 | if (sysrq->active && value && value != 2) { | |
815 | sysrq->need_reinject = false; | |
816 | __handle_sysrq(sysrq_xlate[code], true); | |
817 | } | |
818 | break; | |
819 | } | |
fcb71930 | 820 | |
154b7a48 | 821 | suppress = sysrq->active; |
fcb71930 | 822 | |
154b7a48 | 823 | if (!sysrq->active) { |
fcb71930 | 824 | |
154b7a48 MP |
825 | /* |
826 | * See if reset sequence has changed since the last time. | |
827 | */ | |
828 | if (sysrq->reset_seq_version != sysrq_reset_seq_version) | |
829 | sysrq_parse_reset_sequence(sysrq); | |
fcb71930 | 830 | |
154b7a48 MP |
831 | /* |
832 | * If we are not suppressing key presses keep track of | |
833 | * keyboard state so we can release keys that have been | |
834 | * pressed before entering SysRq mode. | |
835 | */ | |
836 | if (value) | |
837 | set_bit(code, sysrq->key_down); | |
838 | else | |
839 | clear_bit(code, sysrq->key_down); | |
840 | ||
841 | if (was_active) | |
842 | schedule_work(&sysrq->reinject_work); | |
843 | ||
39030786 MP |
844 | /* Check for reset sequence */ |
845 | sysrq_detect_reset_sequence(sysrq, code, value); | |
97f5f0cd | 846 | |
154b7a48 MP |
847 | } else if (value == 0 && test_and_clear_bit(code, sysrq->key_down)) { |
848 | /* | |
849 | * Pass on release events for keys that was pressed before | |
850 | * entering SysRq mode. | |
851 | */ | |
852 | suppress = false; | |
853 | } | |
fcb71930 | 854 | |
154b7a48 MP |
855 | return suppress; |
856 | } | |
fcb71930 | 857 | |
154b7a48 MP |
858 | static bool sysrq_filter(struct input_handle *handle, |
859 | unsigned int type, unsigned int code, int value) | |
860 | { | |
861 | struct sysrq_state *sysrq = handle->private; | |
862 | bool suppress; | |
fcb71930 | 863 | |
154b7a48 MP |
864 | /* |
865 | * Do not filter anything if we are in the process of re-injecting | |
866 | * Alt+SysRq combination. | |
867 | */ | |
868 | if (sysrq->reinjecting) | |
869 | return false; | |
870 | ||
871 | switch (type) { | |
872 | ||
873 | case EV_SYN: | |
874 | suppress = false; | |
875 | break; | |
876 | ||
877 | case EV_KEY: | |
878 | suppress = sysrq_handle_keypress(sysrq, code, value); | |
97f5f0cd DT |
879 | break; |
880 | ||
881 | default: | |
fcb71930 | 882 | suppress = sysrq->active; |
97f5f0cd DT |
883 | break; |
884 | } | |
885 | ||
1966cb22 | 886 | return suppress; |
97f5f0cd DT |
887 | } |
888 | ||
889 | static int sysrq_connect(struct input_handler *handler, | |
890 | struct input_dev *dev, | |
891 | const struct input_device_id *id) | |
892 | { | |
fcb71930 | 893 | struct sysrq_state *sysrq; |
97f5f0cd DT |
894 | int error; |
895 | ||
fcb71930 DT |
896 | sysrq = kzalloc(sizeof(struct sysrq_state), GFP_KERNEL); |
897 | if (!sysrq) | |
97f5f0cd DT |
898 | return -ENOMEM; |
899 | ||
fcb71930 DT |
900 | INIT_WORK(&sysrq->reinject_work, sysrq_reinject_alt_sysrq); |
901 | ||
902 | sysrq->handle.dev = dev; | |
903 | sysrq->handle.handler = handler; | |
904 | sysrq->handle.name = "sysrq"; | |
905 | sysrq->handle.private = sysrq; | |
8c318fa9 | 906 | timer_setup(&sysrq->keyreset_timer, sysrq_do_reset, 0); |
97f5f0cd | 907 | |
fcb71930 | 908 | error = input_register_handle(&sysrq->handle); |
97f5f0cd DT |
909 | if (error) { |
910 | pr_err("Failed to register input sysrq handler, error %d\n", | |
911 | error); | |
912 | goto err_free; | |
913 | } | |
914 | ||
fcb71930 | 915 | error = input_open_device(&sysrq->handle); |
97f5f0cd DT |
916 | if (error) { |
917 | pr_err("Failed to open input device, error %d\n", error); | |
918 | goto err_unregister; | |
919 | } | |
920 | ||
921 | return 0; | |
922 | ||
923 | err_unregister: | |
fcb71930 | 924 | input_unregister_handle(&sysrq->handle); |
97f5f0cd | 925 | err_free: |
fcb71930 | 926 | kfree(sysrq); |
97f5f0cd DT |
927 | return error; |
928 | } | |
929 | ||
930 | static void sysrq_disconnect(struct input_handle *handle) | |
931 | { | |
fcb71930 DT |
932 | struct sysrq_state *sysrq = handle->private; |
933 | ||
97f5f0cd | 934 | input_close_device(handle); |
fcb71930 | 935 | cancel_work_sync(&sysrq->reinject_work); |
39030786 | 936 | del_timer_sync(&sysrq->keyreset_timer); |
97f5f0cd | 937 | input_unregister_handle(handle); |
fcb71930 | 938 | kfree(sysrq); |
97f5f0cd DT |
939 | } |
940 | ||
941 | /* | |
1966cb22 DT |
942 | * We are matching on KEY_LEFTALT instead of KEY_SYSRQ because not all |
943 | * keyboards have SysRq key predefined and so user may add it to keymap | |
97f5f0cd DT |
944 | * later, but we expect all such keyboards to have left alt. |
945 | */ | |
946 | static const struct input_device_id sysrq_ids[] = { | |
947 | { | |
948 | .flags = INPUT_DEVICE_ID_MATCH_EVBIT | | |
949 | INPUT_DEVICE_ID_MATCH_KEYBIT, | |
802c0388 AM |
950 | .evbit = { [BIT_WORD(EV_KEY)] = BIT_MASK(EV_KEY) }, |
951 | .keybit = { [BIT_WORD(KEY_LEFTALT)] = BIT_MASK(KEY_LEFTALT) }, | |
97f5f0cd DT |
952 | }, |
953 | { }, | |
954 | }; | |
955 | ||
956 | static struct input_handler sysrq_handler = { | |
957 | .filter = sysrq_filter, | |
958 | .connect = sysrq_connect, | |
959 | .disconnect = sysrq_disconnect, | |
960 | .name = "sysrq", | |
961 | .id_table = sysrq_ids, | |
962 | }; | |
963 | ||
964 | static bool sysrq_handler_registered; | |
965 | ||
966 | static inline void sysrq_register_handler(void) | |
967 | { | |
968 | int error; | |
969 | ||
4c076eb0 MP |
970 | sysrq_of_get_keyreset_config(); |
971 | ||
97f5f0cd DT |
972 | error = input_register_handler(&sysrq_handler); |
973 | if (error) | |
974 | pr_err("Failed to register input handler, error %d", error); | |
975 | else | |
976 | sysrq_handler_registered = true; | |
977 | } | |
978 | ||
979 | static inline void sysrq_unregister_handler(void) | |
980 | { | |
981 | if (sysrq_handler_registered) { | |
982 | input_unregister_handler(&sysrq_handler); | |
983 | sysrq_handler_registered = false; | |
984 | } | |
985 | } | |
986 | ||
154b7a48 MP |
987 | static int sysrq_reset_seq_param_set(const char *buffer, |
988 | const struct kernel_param *kp) | |
989 | { | |
990 | unsigned long val; | |
991 | int error; | |
992 | ||
86b40567 | 993 | error = kstrtoul(buffer, 0, &val); |
154b7a48 MP |
994 | if (error < 0) |
995 | return error; | |
996 | ||
997 | if (val > KEY_MAX) | |
998 | return -EINVAL; | |
999 | ||
1000 | *((unsigned short *)kp->arg) = val; | |
1001 | sysrq_reset_seq_version++; | |
1002 | ||
1003 | return 0; | |
1004 | } | |
1005 | ||
9c27847d | 1006 | static const struct kernel_param_ops param_ops_sysrq_reset_seq = { |
154b7a48 MP |
1007 | .get = param_get_ushort, |
1008 | .set = sysrq_reset_seq_param_set, | |
1009 | }; | |
1010 | ||
1011 | #define param_check_sysrq_reset_seq(name, p) \ | |
1012 | __param_check(name, p, unsigned short) | |
1013 | ||
3bce6f64 PG |
1014 | /* |
1015 | * not really modular, but the easiest way to keep compat with existing | |
1016 | * bootargs behaviour is to continue using module_param here. | |
1017 | */ | |
154b7a48 MP |
1018 | module_param_array_named(reset_seq, sysrq_reset_seq, sysrq_reset_seq, |
1019 | &sysrq_reset_seq_len, 0644); | |
1020 | ||
39030786 MP |
1021 | module_param_named(sysrq_downtime_ms, sysrq_reset_downtime_ms, int, 0644); |
1022 | ||
97f5f0cd DT |
1023 | #else |
1024 | ||
1025 | static inline void sysrq_register_handler(void) | |
1026 | { | |
1027 | } | |
1028 | ||
1029 | static inline void sysrq_unregister_handler(void) | |
1030 | { | |
1031 | } | |
1032 | ||
1033 | #endif /* CONFIG_INPUT */ | |
1034 | ||
1035 | int sysrq_toggle_support(int enable_mask) | |
1036 | { | |
1037 | bool was_enabled = sysrq_on(); | |
1038 | ||
1039 | sysrq_enabled = enable_mask; | |
1040 | ||
1041 | if (was_enabled != sysrq_on()) { | |
1042 | if (sysrq_on()) | |
1043 | sysrq_register_handler(); | |
1044 | else | |
1045 | sysrq_unregister_handler(); | |
1046 | } | |
1047 | ||
1048 | return 0; | |
1049 | } | |
1050 | ||
cf62ddce | 1051 | static int __sysrq_swap_key_ops(int key, struct sysrq_key_op *insert_op_p, |
bf36b901 AM |
1052 | struct sysrq_key_op *remove_op_p) |
1053 | { | |
1da177e4 | 1054 | int retval; |
1da177e4 | 1055 | |
984d74a7 | 1056 | spin_lock(&sysrq_key_table_lock); |
1da177e4 LT |
1057 | if (__sysrq_get_key_op(key) == remove_op_p) { |
1058 | __sysrq_put_key_op(key, insert_op_p); | |
1059 | retval = 0; | |
1060 | } else { | |
1061 | retval = -1; | |
1062 | } | |
984d74a7 RR |
1063 | spin_unlock(&sysrq_key_table_lock); |
1064 | ||
1065 | /* | |
1066 | * A concurrent __handle_sysrq either got the old op or the new op. | |
1067 | * Wait for it to go away before returning, so the code for an old | |
1068 | * op is not freed (eg. on module unload) while it is in use. | |
1069 | */ | |
1070 | synchronize_rcu(); | |
1071 | ||
1da177e4 LT |
1072 | return retval; |
1073 | } | |
1074 | ||
1075 | int register_sysrq_key(int key, struct sysrq_key_op *op_p) | |
1076 | { | |
1077 | return __sysrq_swap_key_ops(key, op_p, NULL); | |
1078 | } | |
bf36b901 | 1079 | EXPORT_SYMBOL(register_sysrq_key); |
1da177e4 LT |
1080 | |
1081 | int unregister_sysrq_key(int key, struct sysrq_key_op *op_p) | |
1082 | { | |
1083 | return __sysrq_swap_key_ops(key, NULL, op_p); | |
1084 | } | |
1da177e4 | 1085 | EXPORT_SYMBOL(unregister_sysrq_key); |
f40cbaa5 AD |
1086 | |
1087 | #ifdef CONFIG_PROC_FS | |
1088 | /* | |
1089 | * writing 'C' to /proc/sysrq-trigger is like sysrq-C | |
1090 | */ | |
1091 | static ssize_t write_sysrq_trigger(struct file *file, const char __user *buf, | |
1092 | size_t count, loff_t *ppos) | |
1093 | { | |
1094 | if (count) { | |
1095 | char c; | |
1096 | ||
1097 | if (get_user(c, buf)) | |
1098 | return -EFAULT; | |
f335397d | 1099 | __handle_sysrq(c, false); |
f40cbaa5 | 1100 | } |
97f5f0cd | 1101 | |
f40cbaa5 AD |
1102 | return count; |
1103 | } | |
1104 | ||
1105 | static const struct file_operations proc_sysrq_trigger_operations = { | |
1106 | .write = write_sysrq_trigger, | |
6038f373 | 1107 | .llseek = noop_llseek, |
f40cbaa5 AD |
1108 | }; |
1109 | ||
97f5f0cd DT |
1110 | static void sysrq_init_procfs(void) |
1111 | { | |
1112 | if (!proc_create("sysrq-trigger", S_IWUSR, NULL, | |
1113 | &proc_sysrq_trigger_operations)) | |
1114 | pr_err("Failed to register proc interface\n"); | |
1115 | } | |
1116 | ||
1117 | #else | |
1118 | ||
1119 | static inline void sysrq_init_procfs(void) | |
1120 | { | |
1121 | } | |
1122 | ||
1123 | #endif /* CONFIG_PROC_FS */ | |
1124 | ||
f40cbaa5 AD |
1125 | static int __init sysrq_init(void) |
1126 | { | |
97f5f0cd DT |
1127 | sysrq_init_procfs(); |
1128 | ||
1129 | if (sysrq_on()) | |
1130 | sysrq_register_handler(); | |
1131 | ||
f40cbaa5 AD |
1132 | return 0; |
1133 | } | |
3bce6f64 | 1134 | device_initcall(sysrq_init); |