Commit | Line | Data |
---|---|---|
97f5f0cd | 1 | /* |
1da177e4 LT |
2 | * Linux Magic System Request Key Hacks |
3 | * | |
4 | * (c) 1997 Martin Mares <mj@atrey.karlin.mff.cuni.cz> | |
5 | * based on ideas by Pavel Machek <pavel@atrey.karlin.mff.cuni.cz> | |
6 | * | |
7 | * (c) 2000 Crutcher Dunnavant <crutcher+kernel@datastacks.com> | |
8 | * overhauled to use key registration | |
9 | * based upon discusions in irc://irc.openprojects.net/#kernelnewbies | |
97f5f0cd DT |
10 | * |
11 | * Copyright (c) 2010 Dmitry Torokhov | |
12 | * Input handler conversion | |
1da177e4 LT |
13 | */ |
14 | ||
97f5f0cd DT |
15 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
16 | ||
1da177e4 | 17 | #include <linux/sched.h> |
8bd75c77 | 18 | #include <linux/sched/rt.h> |
1da177e4 LT |
19 | #include <linux/interrupt.h> |
20 | #include <linux/mm.h> | |
21 | #include <linux/fs.h> | |
1da177e4 LT |
22 | #include <linux/mount.h> |
23 | #include <linux/kdev_t.h> | |
24 | #include <linux/major.h> | |
25 | #include <linux/reboot.h> | |
26 | #include <linux/sysrq.h> | |
27 | #include <linux/kbd_kern.h> | |
f40cbaa5 | 28 | #include <linux/proc_fs.h> |
c1dc0b9c | 29 | #include <linux/nmi.h> |
1da177e4 | 30 | #include <linux/quotaops.h> |
cdd6c482 | 31 | #include <linux/perf_event.h> |
1da177e4 LT |
32 | #include <linux/kernel.h> |
33 | #include <linux/module.h> | |
34 | #include <linux/suspend.h> | |
35 | #include <linux/writeback.h> | |
1da177e4 LT |
36 | #include <linux/swap.h> |
37 | #include <linux/spinlock.h> | |
38 | #include <linux/vt_kern.h> | |
39 | #include <linux/workqueue.h> | |
88ad0bf6 | 40 | #include <linux/hrtimer.h> |
5a3135c2 | 41 | #include <linux/oom.h> |
5a0e3ad6 | 42 | #include <linux/slab.h> |
97f5f0cd | 43 | #include <linux/input.h> |
ff01bb48 | 44 | #include <linux/uaccess.h> |
154b7a48 | 45 | #include <linux/moduleparam.h> |
39030786 | 46 | #include <linux/jiffies.h> |
3d289517 | 47 | #include <linux/syscalls.h> |
1da177e4 LT |
48 | |
49 | #include <asm/ptrace.h> | |
2033b0c3 | 50 | #include <asm/irq_regs.h> |
1da177e4 LT |
51 | |
52 | /* Whether we react on sysrq keys or just ignore them */ | |
8c6a98b2 | 53 | static int __read_mostly sysrq_enabled = SYSRQ_DEFAULT_ENABLE; |
97f5f0cd | 54 | static bool __read_mostly sysrq_always_enabled; |
5d6f647f | 55 | |
39030786 MP |
56 | unsigned short platform_sysrq_reset_seq[] __weak = { KEY_RESERVED }; |
57 | int sysrq_reset_downtime_ms __weak; | |
58 | ||
97f5f0cd | 59 | static bool sysrq_on(void) |
5d6f647f | 60 | { |
97f5f0cd | 61 | return sysrq_enabled || sysrq_always_enabled; |
5d6f647f IM |
62 | } |
63 | ||
64 | /* | |
65 | * A value of 1 means 'all', other nonzero values are an op mask: | |
66 | */ | |
97f5f0cd | 67 | static bool sysrq_on_mask(int mask) |
5d6f647f | 68 | { |
97f5f0cd DT |
69 | return sysrq_always_enabled || |
70 | sysrq_enabled == 1 || | |
71 | (sysrq_enabled & mask); | |
5d6f647f IM |
72 | } |
73 | ||
74 | static int __init sysrq_always_enabled_setup(char *str) | |
75 | { | |
97f5f0cd DT |
76 | sysrq_always_enabled = true; |
77 | pr_info("sysrq always enabled.\n"); | |
5d6f647f IM |
78 | |
79 | return 1; | |
80 | } | |
81 | ||
82 | __setup("sysrq_always_enabled", sysrq_always_enabled_setup); | |
83 | ||
1da177e4 | 84 | |
1495cc9d | 85 | static void sysrq_handle_loglevel(int key) |
1da177e4 LT |
86 | { |
87 | int i; | |
97f5f0cd | 88 | |
1da177e4 LT |
89 | i = key - '0'; |
90 | console_loglevel = 7; | |
91 | printk("Loglevel set to %d\n", i); | |
92 | console_loglevel = i; | |
bf36b901 | 93 | } |
1da177e4 LT |
94 | static struct sysrq_key_op sysrq_loglevel_op = { |
95 | .handler = sysrq_handle_loglevel, | |
208b95ce | 96 | .help_msg = "loglevel(0-9)", |
1da177e4 LT |
97 | .action_msg = "Changing Loglevel", |
98 | .enable_mask = SYSRQ_ENABLE_LOG, | |
99 | }; | |
100 | ||
1da177e4 | 101 | #ifdef CONFIG_VT |
1495cc9d | 102 | static void sysrq_handle_SAK(int key) |
1da177e4 | 103 | { |
8b6312f4 | 104 | struct work_struct *SAK_work = &vc_cons[fg_console].SAK_work; |
8b6312f4 | 105 | schedule_work(SAK_work); |
1da177e4 LT |
106 | } |
107 | static struct sysrq_key_op sysrq_SAK_op = { | |
108 | .handler = sysrq_handle_SAK, | |
afa80ccb | 109 | .help_msg = "sak(k)", |
1da177e4 LT |
110 | .action_msg = "SAK", |
111 | .enable_mask = SYSRQ_ENABLE_KEYBOARD, | |
112 | }; | |
bf36b901 | 113 | #else |
97f5f0cd | 114 | #define sysrq_SAK_op (*(struct sysrq_key_op *)NULL) |
1da177e4 LT |
115 | #endif |
116 | ||
117 | #ifdef CONFIG_VT | |
1495cc9d | 118 | static void sysrq_handle_unraw(int key) |
1da177e4 | 119 | { |
079c9534 | 120 | vt_reset_unicode(fg_console); |
1da177e4 | 121 | } |
079c9534 | 122 | |
1da177e4 LT |
123 | static struct sysrq_key_op sysrq_unraw_op = { |
124 | .handler = sysrq_handle_unraw, | |
afa80ccb | 125 | .help_msg = "unraw(r)", |
2e8ecb9d | 126 | .action_msg = "Keyboard mode set to system default", |
1da177e4 LT |
127 | .enable_mask = SYSRQ_ENABLE_KEYBOARD, |
128 | }; | |
bf36b901 | 129 | #else |
97f5f0cd | 130 | #define sysrq_unraw_op (*(struct sysrq_key_op *)NULL) |
1da177e4 LT |
131 | #endif /* CONFIG_VT */ |
132 | ||
1495cc9d | 133 | static void sysrq_handle_crash(int key) |
86b1ae38 | 134 | { |
d6580a9f | 135 | char *killer = NULL; |
cab8bd34 HS |
136 | |
137 | panic_on_oops = 1; /* force panic */ | |
138 | wmb(); | |
d6580a9f | 139 | *killer = 1; |
86b1ae38 | 140 | } |
cab8bd34 | 141 | static struct sysrq_key_op sysrq_crash_op = { |
d6580a9f | 142 | .handler = sysrq_handle_crash, |
afa80ccb | 143 | .help_msg = "crash(c)", |
d6580a9f | 144 | .action_msg = "Trigger a crash", |
86b1ae38 HN |
145 | .enable_mask = SYSRQ_ENABLE_DUMP, |
146 | }; | |
86b1ae38 | 147 | |
1495cc9d | 148 | static void sysrq_handle_reboot(int key) |
1da177e4 | 149 | { |
b2e9c7d0 | 150 | lockdep_off(); |
1da177e4 | 151 | local_irq_enable(); |
4de8b9b7 | 152 | emergency_restart(); |
1da177e4 | 153 | } |
1da177e4 LT |
154 | static struct sysrq_key_op sysrq_reboot_op = { |
155 | .handler = sysrq_handle_reboot, | |
afa80ccb | 156 | .help_msg = "reboot(b)", |
1da177e4 LT |
157 | .action_msg = "Resetting", |
158 | .enable_mask = SYSRQ_ENABLE_BOOT, | |
159 | }; | |
160 | ||
1495cc9d | 161 | static void sysrq_handle_sync(int key) |
1da177e4 LT |
162 | { |
163 | emergency_sync(); | |
164 | } | |
1da177e4 LT |
165 | static struct sysrq_key_op sysrq_sync_op = { |
166 | .handler = sysrq_handle_sync, | |
afa80ccb | 167 | .help_msg = "sync(s)", |
1da177e4 LT |
168 | .action_msg = "Emergency Sync", |
169 | .enable_mask = SYSRQ_ENABLE_SYNC, | |
170 | }; | |
171 | ||
1495cc9d | 172 | static void sysrq_handle_show_timers(int key) |
88ad0bf6 IM |
173 | { |
174 | sysrq_timer_list_show(); | |
175 | } | |
176 | ||
177 | static struct sysrq_key_op sysrq_show_timers_op = { | |
178 | .handler = sysrq_handle_show_timers, | |
afa80ccb | 179 | .help_msg = "show-all-timers(q)", |
322acf65 | 180 | .action_msg = "Show clockevent devices & pending hrtimers (no others)", |
88ad0bf6 IM |
181 | }; |
182 | ||
1495cc9d | 183 | static void sysrq_handle_mountro(int key) |
1da177e4 LT |
184 | { |
185 | emergency_remount(); | |
186 | } | |
1da177e4 LT |
187 | static struct sysrq_key_op sysrq_mountro_op = { |
188 | .handler = sysrq_handle_mountro, | |
afa80ccb | 189 | .help_msg = "unmount(u)", |
1da177e4 LT |
190 | .action_msg = "Emergency Remount R/O", |
191 | .enable_mask = SYSRQ_ENABLE_REMOUNT, | |
192 | }; | |
193 | ||
8c64580d | 194 | #ifdef CONFIG_LOCKDEP |
1495cc9d | 195 | static void sysrq_handle_showlocks(int key) |
de5097c2 | 196 | { |
9a11b49a | 197 | debug_show_all_locks(); |
de5097c2 | 198 | } |
8c64580d | 199 | |
de5097c2 IM |
200 | static struct sysrq_key_op sysrq_showlocks_op = { |
201 | .handler = sysrq_handle_showlocks, | |
afa80ccb | 202 | .help_msg = "show-all-locks(d)", |
de5097c2 IM |
203 | .action_msg = "Show Locks Held", |
204 | }; | |
bf36b901 | 205 | #else |
97f5f0cd | 206 | #define sysrq_showlocks_op (*(struct sysrq_key_op *)NULL) |
de5097c2 | 207 | #endif |
1da177e4 | 208 | |
5045bcae RR |
209 | #ifdef CONFIG_SMP |
210 | static DEFINE_SPINLOCK(show_lock); | |
211 | ||
212 | static void showacpu(void *dummy) | |
213 | { | |
214 | unsigned long flags; | |
215 | ||
216 | /* Idle CPUs have no interesting backtrace. */ | |
217 | if (idle_cpu(smp_processor_id())) | |
218 | return; | |
219 | ||
220 | spin_lock_irqsave(&show_lock, flags); | |
221 | printk(KERN_INFO "CPU%d:\n", smp_processor_id()); | |
222 | show_stack(NULL, NULL); | |
223 | spin_unlock_irqrestore(&show_lock, flags); | |
224 | } | |
225 | ||
226 | static void sysrq_showregs_othercpus(struct work_struct *dummy) | |
227 | { | |
8b604d52 | 228 | smp_call_function(showacpu, NULL, 0); |
5045bcae RR |
229 | } |
230 | ||
231 | static DECLARE_WORK(sysrq_showallcpus, sysrq_showregs_othercpus); | |
232 | ||
1495cc9d | 233 | static void sysrq_handle_showallcpus(int key) |
5045bcae | 234 | { |
47cab6a7 IM |
235 | /* |
236 | * Fall back to the workqueue based printing if the | |
237 | * backtrace printing did not succeed or the | |
238 | * architecture has no support for it: | |
239 | */ | |
240 | if (!trigger_all_cpu_backtrace()) { | |
241 | struct pt_regs *regs = get_irq_regs(); | |
242 | ||
243 | if (regs) { | |
244 | printk(KERN_INFO "CPU%d:\n", smp_processor_id()); | |
245 | show_regs(regs); | |
246 | } | |
247 | schedule_work(&sysrq_showallcpus); | |
248 | } | |
5045bcae RR |
249 | } |
250 | ||
251 | static struct sysrq_key_op sysrq_showallcpus_op = { | |
252 | .handler = sysrq_handle_showallcpus, | |
afa80ccb | 253 | .help_msg = "show-backtrace-all-active-cpus(l)", |
5045bcae RR |
254 | .action_msg = "Show backtrace of all active CPUs", |
255 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
256 | }; | |
257 | #endif | |
258 | ||
1495cc9d | 259 | static void sysrq_handle_showregs(int key) |
1da177e4 | 260 | { |
7d12e780 DH |
261 | struct pt_regs *regs = get_irq_regs(); |
262 | if (regs) | |
263 | show_regs(regs); | |
cdd6c482 | 264 | perf_event_print_debug(); |
1da177e4 LT |
265 | } |
266 | static struct sysrq_key_op sysrq_showregs_op = { | |
267 | .handler = sysrq_handle_showregs, | |
afa80ccb | 268 | .help_msg = "show-registers(p)", |
1da177e4 LT |
269 | .action_msg = "Show Regs", |
270 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
271 | }; | |
272 | ||
1495cc9d | 273 | static void sysrq_handle_showstate(int key) |
1da177e4 LT |
274 | { |
275 | show_state(); | |
276 | } | |
277 | static struct sysrq_key_op sysrq_showstate_op = { | |
278 | .handler = sysrq_handle_showstate, | |
afa80ccb | 279 | .help_msg = "show-task-states(t)", |
1da177e4 LT |
280 | .action_msg = "Show State", |
281 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
282 | }; | |
283 | ||
1495cc9d | 284 | static void sysrq_handle_showstate_blocked(int key) |
e59e2ae2 IM |
285 | { |
286 | show_state_filter(TASK_UNINTERRUPTIBLE); | |
287 | } | |
288 | static struct sysrq_key_op sysrq_showstate_blocked_op = { | |
289 | .handler = sysrq_handle_showstate_blocked, | |
afa80ccb | 290 | .help_msg = "show-blocked-tasks(w)", |
e59e2ae2 IM |
291 | .action_msg = "Show Blocked State", |
292 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
293 | }; | |
294 | ||
69f698ad PZ |
295 | #ifdef CONFIG_TRACING |
296 | #include <linux/ftrace.h> | |
297 | ||
1495cc9d | 298 | static void sysrq_ftrace_dump(int key) |
69f698ad | 299 | { |
cecbca96 | 300 | ftrace_dump(DUMP_ALL); |
69f698ad PZ |
301 | } |
302 | static struct sysrq_key_op sysrq_ftrace_dump_op = { | |
303 | .handler = sysrq_ftrace_dump, | |
afa80ccb | 304 | .help_msg = "dump-ftrace-buffer(z)", |
69f698ad PZ |
305 | .action_msg = "Dump ftrace buffer", |
306 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
307 | }; | |
308 | #else | |
97f5f0cd | 309 | #define sysrq_ftrace_dump_op (*(struct sysrq_key_op *)NULL) |
69f698ad | 310 | #endif |
e59e2ae2 | 311 | |
1495cc9d | 312 | static void sysrq_handle_showmem(int key) |
1da177e4 | 313 | { |
b2b755b5 | 314 | show_mem(0); |
1da177e4 LT |
315 | } |
316 | static struct sysrq_key_op sysrq_showmem_op = { | |
317 | .handler = sysrq_handle_showmem, | |
afa80ccb | 318 | .help_msg = "show-memory-usage(m)", |
1da177e4 LT |
319 | .action_msg = "Show Memory", |
320 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
321 | }; | |
322 | ||
bf36b901 AM |
323 | /* |
324 | * Signal sysrq helper function. Sends a signal to all user processes. | |
325 | */ | |
1da177e4 LT |
326 | static void send_sig_all(int sig) |
327 | { | |
328 | struct task_struct *p; | |
329 | ||
e502babe | 330 | read_lock(&tasklist_lock); |
1da177e4 | 331 | for_each_process(p) { |
d3a532a9 AV |
332 | if (p->flags & PF_KTHREAD) |
333 | continue; | |
334 | if (is_global_init(p)) | |
335 | continue; | |
336 | ||
b82c3287 | 337 | do_send_sig_info(sig, SEND_SIG_FORCED, p, true); |
1da177e4 | 338 | } |
e502babe | 339 | read_unlock(&tasklist_lock); |
1da177e4 LT |
340 | } |
341 | ||
1495cc9d | 342 | static void sysrq_handle_term(int key) |
1da177e4 LT |
343 | { |
344 | send_sig_all(SIGTERM); | |
345 | console_loglevel = 8; | |
346 | } | |
347 | static struct sysrq_key_op sysrq_term_op = { | |
348 | .handler = sysrq_handle_term, | |
afa80ccb | 349 | .help_msg = "terminate-all-tasks(e)", |
1da177e4 LT |
350 | .action_msg = "Terminate All Tasks", |
351 | .enable_mask = SYSRQ_ENABLE_SIGNAL, | |
352 | }; | |
353 | ||
65f27f38 | 354 | static void moom_callback(struct work_struct *ignored) |
1da177e4 | 355 | { |
53186095 DR |
356 | out_of_memory(node_zonelist(first_online_node, GFP_KERNEL), GFP_KERNEL, |
357 | 0, NULL, true); | |
1da177e4 LT |
358 | } |
359 | ||
65f27f38 | 360 | static DECLARE_WORK(moom_work, moom_callback); |
1da177e4 | 361 | |
1495cc9d | 362 | static void sysrq_handle_moom(int key) |
1da177e4 LT |
363 | { |
364 | schedule_work(&moom_work); | |
365 | } | |
366 | static struct sysrq_key_op sysrq_moom_op = { | |
367 | .handler = sysrq_handle_moom, | |
afa80ccb | 368 | .help_msg = "memory-full-oom-kill(f)", |
1da177e4 | 369 | .action_msg = "Manual OOM execution", |
b4236f81 | 370 | .enable_mask = SYSRQ_ENABLE_SIGNAL, |
1da177e4 LT |
371 | }; |
372 | ||
c2d75438 | 373 | #ifdef CONFIG_BLOCK |
1495cc9d | 374 | static void sysrq_handle_thaw(int key) |
c2d75438 ES |
375 | { |
376 | emergency_thaw_all(); | |
377 | } | |
378 | static struct sysrq_key_op sysrq_thaw_op = { | |
379 | .handler = sysrq_handle_thaw, | |
afa80ccb | 380 | .help_msg = "thaw-filesystems(j)", |
c2d75438 ES |
381 | .action_msg = "Emergency Thaw of all frozen filesystems", |
382 | .enable_mask = SYSRQ_ENABLE_SIGNAL, | |
383 | }; | |
384 | #endif | |
385 | ||
1495cc9d | 386 | static void sysrq_handle_kill(int key) |
1da177e4 LT |
387 | { |
388 | send_sig_all(SIGKILL); | |
389 | console_loglevel = 8; | |
390 | } | |
391 | static struct sysrq_key_op sysrq_kill_op = { | |
392 | .handler = sysrq_handle_kill, | |
afa80ccb | 393 | .help_msg = "kill-all-tasks(i)", |
1da177e4 LT |
394 | .action_msg = "Kill All Tasks", |
395 | .enable_mask = SYSRQ_ENABLE_SIGNAL, | |
396 | }; | |
397 | ||
1495cc9d | 398 | static void sysrq_handle_unrt(int key) |
1da177e4 LT |
399 | { |
400 | normalize_rt_tasks(); | |
401 | } | |
402 | static struct sysrq_key_op sysrq_unrt_op = { | |
403 | .handler = sysrq_handle_unrt, | |
afa80ccb | 404 | .help_msg = "nice-all-RT-tasks(n)", |
1da177e4 LT |
405 | .action_msg = "Nice All RT Tasks", |
406 | .enable_mask = SYSRQ_ENABLE_RTNICE, | |
407 | }; | |
408 | ||
409 | /* Key Operations table and lock */ | |
410 | static DEFINE_SPINLOCK(sysrq_key_table_lock); | |
bf36b901 AM |
411 | |
412 | static struct sysrq_key_op *sysrq_key_table[36] = { | |
413 | &sysrq_loglevel_op, /* 0 */ | |
414 | &sysrq_loglevel_op, /* 1 */ | |
415 | &sysrq_loglevel_op, /* 2 */ | |
416 | &sysrq_loglevel_op, /* 3 */ | |
417 | &sysrq_loglevel_op, /* 4 */ | |
418 | &sysrq_loglevel_op, /* 5 */ | |
419 | &sysrq_loglevel_op, /* 6 */ | |
420 | &sysrq_loglevel_op, /* 7 */ | |
421 | &sysrq_loglevel_op, /* 8 */ | |
422 | &sysrq_loglevel_op, /* 9 */ | |
423 | ||
424 | /* | |
d346cce3 RD |
425 | * a: Don't use for system provided sysrqs, it is handled specially on |
426 | * sparc and will never arrive. | |
bf36b901 AM |
427 | */ |
428 | NULL, /* a */ | |
429 | &sysrq_reboot_op, /* b */ | |
cab8bd34 | 430 | &sysrq_crash_op, /* c & ibm_emac driver debug */ |
bf36b901 AM |
431 | &sysrq_showlocks_op, /* d */ |
432 | &sysrq_term_op, /* e */ | |
433 | &sysrq_moom_op, /* f */ | |
364b5b7b | 434 | /* g: May be registered for the kernel debugger */ |
bf36b901 | 435 | NULL, /* g */ |
c2d75438 | 436 | NULL, /* h - reserved for help */ |
bf36b901 | 437 | &sysrq_kill_op, /* i */ |
c2d75438 ES |
438 | #ifdef CONFIG_BLOCK |
439 | &sysrq_thaw_op, /* j */ | |
440 | #else | |
bf36b901 | 441 | NULL, /* j */ |
c2d75438 | 442 | #endif |
bf36b901 | 443 | &sysrq_SAK_op, /* k */ |
5045bcae RR |
444 | #ifdef CONFIG_SMP |
445 | &sysrq_showallcpus_op, /* l */ | |
446 | #else | |
bf36b901 | 447 | NULL, /* l */ |
5045bcae | 448 | #endif |
bf36b901 AM |
449 | &sysrq_showmem_op, /* m */ |
450 | &sysrq_unrt_op, /* n */ | |
d346cce3 | 451 | /* o: This will often be registered as 'Off' at init time */ |
bf36b901 AM |
452 | NULL, /* o */ |
453 | &sysrq_showregs_op, /* p */ | |
88ad0bf6 | 454 | &sysrq_show_timers_op, /* q */ |
d346cce3 | 455 | &sysrq_unraw_op, /* r */ |
bf36b901 AM |
456 | &sysrq_sync_op, /* s */ |
457 | &sysrq_showstate_op, /* t */ | |
458 | &sysrq_mountro_op, /* u */ | |
364b5b7b | 459 | /* v: May be registered for frame buffer console restore */ |
bf36b901 | 460 | NULL, /* v */ |
d346cce3 RD |
461 | &sysrq_showstate_blocked_op, /* w */ |
462 | /* x: May be registered on ppc/powerpc for xmon */ | |
916ca14a | 463 | /* x: May be registered on sparc64 for global PMU dump */ |
d346cce3 | 464 | NULL, /* x */ |
93dae5b7 | 465 | /* y: May be registered on sparc64 for global register dump */ |
bf36b901 | 466 | NULL, /* y */ |
69f698ad | 467 | &sysrq_ftrace_dump_op, /* z */ |
1da177e4 LT |
468 | }; |
469 | ||
470 | /* key2index calculation, -1 on invalid index */ | |
bf36b901 AM |
471 | static int sysrq_key_table_key2index(int key) |
472 | { | |
1da177e4 | 473 | int retval; |
bf36b901 AM |
474 | |
475 | if ((key >= '0') && (key <= '9')) | |
1da177e4 | 476 | retval = key - '0'; |
bf36b901 | 477 | else if ((key >= 'a') && (key <= 'z')) |
1da177e4 | 478 | retval = key + 10 - 'a'; |
bf36b901 | 479 | else |
1da177e4 | 480 | retval = -1; |
1da177e4 LT |
481 | return retval; |
482 | } | |
483 | ||
484 | /* | |
485 | * get and put functions for the table, exposed to modules. | |
486 | */ | |
bf36b901 AM |
487 | struct sysrq_key_op *__sysrq_get_key_op(int key) |
488 | { | |
489 | struct sysrq_key_op *op_p = NULL; | |
1da177e4 | 490 | int i; |
bf36b901 | 491 | |
1da177e4 | 492 | i = sysrq_key_table_key2index(key); |
bf36b901 AM |
493 | if (i != -1) |
494 | op_p = sysrq_key_table[i]; | |
97f5f0cd | 495 | |
1da177e4 LT |
496 | return op_p; |
497 | } | |
498 | ||
bf36b901 AM |
499 | static void __sysrq_put_key_op(int key, struct sysrq_key_op *op_p) |
500 | { | |
501 | int i = sysrq_key_table_key2index(key); | |
1da177e4 | 502 | |
1da177e4 LT |
503 | if (i != -1) |
504 | sysrq_key_table[i] = op_p; | |
505 | } | |
506 | ||
f335397d | 507 | void __handle_sysrq(int key, bool check_mask) |
1da177e4 LT |
508 | { |
509 | struct sysrq_key_op *op_p; | |
510 | int orig_log_level; | |
bf36b901 | 511 | int i; |
1da177e4 LT |
512 | unsigned long flags; |
513 | ||
514 | spin_lock_irqsave(&sysrq_key_table_lock, flags); | |
fb144adc AW |
515 | /* |
516 | * Raise the apparent loglevel to maximum so that the sysrq header | |
517 | * is shown to provide the user with positive feedback. We do not | |
518 | * simply emit this at KERN_EMERG as that would change message | |
519 | * routing in the consumers of /proc/kmsg. | |
520 | */ | |
1da177e4 LT |
521 | orig_log_level = console_loglevel; |
522 | console_loglevel = 7; | |
523 | printk(KERN_INFO "SysRq : "); | |
524 | ||
525 | op_p = __sysrq_get_key_op(key); | |
526 | if (op_p) { | |
bf36b901 AM |
527 | /* |
528 | * Should we check for enabled operations (/proc/sysrq-trigger | |
529 | * should not) and is the invoked operation enabled? | |
530 | */ | |
5d6f647f | 531 | if (!check_mask || sysrq_on_mask(op_p->enable_mask)) { |
bf36b901 | 532 | printk("%s\n", op_p->action_msg); |
1da177e4 | 533 | console_loglevel = orig_log_level; |
1495cc9d | 534 | op_p->handler(key); |
bf36b901 | 535 | } else { |
1da177e4 | 536 | printk("This sysrq operation is disabled.\n"); |
bf36b901 | 537 | } |
1da177e4 LT |
538 | } else { |
539 | printk("HELP : "); | |
540 | /* Only print the help msg once per handler */ | |
bf36b901 AM |
541 | for (i = 0; i < ARRAY_SIZE(sysrq_key_table); i++) { |
542 | if (sysrq_key_table[i]) { | |
543 | int j; | |
544 | ||
545 | for (j = 0; sysrq_key_table[i] != | |
546 | sysrq_key_table[j]; j++) | |
547 | ; | |
548 | if (j != i) | |
549 | continue; | |
550 | printk("%s ", sysrq_key_table[i]->help_msg); | |
551 | } | |
1da177e4 | 552 | } |
bf36b901 | 553 | printk("\n"); |
1da177e4 LT |
554 | console_loglevel = orig_log_level; |
555 | } | |
556 | spin_unlock_irqrestore(&sysrq_key_table_lock, flags); | |
557 | } | |
558 | ||
f335397d | 559 | void handle_sysrq(int key) |
1da177e4 | 560 | { |
5d6f647f | 561 | if (sysrq_on()) |
f335397d | 562 | __handle_sysrq(key, true); |
1da177e4 | 563 | } |
bf36b901 | 564 | EXPORT_SYMBOL(handle_sysrq); |
1da177e4 | 565 | |
97f5f0cd DT |
566 | #ifdef CONFIG_INPUT |
567 | ||
568 | /* Simple translation table for the SysRq keys */ | |
fcb71930 | 569 | static const unsigned char sysrq_xlate[KEY_CNT] = |
97f5f0cd DT |
570 | "\000\0331234567890-=\177\t" /* 0x00 - 0x0f */ |
571 | "qwertyuiop[]\r\000as" /* 0x10 - 0x1f */ | |
572 | "dfghjkl;'`\000\\zxcv" /* 0x20 - 0x2f */ | |
573 | "bnm,./\000*\000 \000\201\202\203\204\205" /* 0x30 - 0x3f */ | |
574 | "\206\207\210\211\212\000\000789-456+1" /* 0x40 - 0x4f */ | |
575 | "230\177\000\000\213\214\000\000\000\000\000\000\000\000\000\000" /* 0x50 - 0x5f */ | |
576 | "\r\000/"; /* 0x60 - 0x6f */ | |
577 | ||
fcb71930 DT |
578 | struct sysrq_state { |
579 | struct input_handle handle; | |
580 | struct work_struct reinject_work; | |
581 | unsigned long key_down[BITS_TO_LONGS(KEY_CNT)]; | |
582 | unsigned int alt; | |
583 | unsigned int alt_use; | |
584 | bool active; | |
585 | bool need_reinject; | |
7ab7b5ad | 586 | bool reinjecting; |
154b7a48 MP |
587 | |
588 | /* reset sequence handling */ | |
589 | bool reset_canceled; | |
3d289517 | 590 | bool reset_requested; |
154b7a48 MP |
591 | unsigned long reset_keybit[BITS_TO_LONGS(KEY_CNT)]; |
592 | int reset_seq_len; | |
593 | int reset_seq_cnt; | |
594 | int reset_seq_version; | |
39030786 | 595 | struct timer_list keyreset_timer; |
fcb71930 DT |
596 | }; |
597 | ||
154b7a48 MP |
598 | #define SYSRQ_KEY_RESET_MAX 20 /* Should be plenty */ |
599 | static unsigned short sysrq_reset_seq[SYSRQ_KEY_RESET_MAX]; | |
600 | static unsigned int sysrq_reset_seq_len; | |
601 | static unsigned int sysrq_reset_seq_version = 1; | |
602 | ||
603 | static void sysrq_parse_reset_sequence(struct sysrq_state *state) | |
604 | { | |
605 | int i; | |
606 | unsigned short key; | |
607 | ||
608 | state->reset_seq_cnt = 0; | |
609 | ||
610 | for (i = 0; i < sysrq_reset_seq_len; i++) { | |
611 | key = sysrq_reset_seq[i]; | |
612 | ||
613 | if (key == KEY_RESERVED || key > KEY_MAX) | |
614 | break; | |
615 | ||
616 | __set_bit(key, state->reset_keybit); | |
617 | state->reset_seq_len++; | |
618 | ||
619 | if (test_bit(key, state->key_down)) | |
620 | state->reset_seq_cnt++; | |
621 | } | |
622 | ||
623 | /* Disable reset until old keys are not released */ | |
624 | state->reset_canceled = state->reset_seq_cnt != 0; | |
625 | ||
626 | state->reset_seq_version = sysrq_reset_seq_version; | |
627 | } | |
628 | ||
3d289517 | 629 | static void sysrq_do_reset(unsigned long _state) |
39030786 | 630 | { |
3d289517 MP |
631 | struct sysrq_state *state = (struct sysrq_state *) _state; |
632 | ||
633 | state->reset_requested = true; | |
634 | ||
635 | sys_sync(); | |
636 | kernel_restart(NULL); | |
39030786 MP |
637 | } |
638 | ||
639 | static void sysrq_handle_reset_request(struct sysrq_state *state) | |
640 | { | |
3d289517 MP |
641 | if (state->reset_requested) |
642 | __handle_sysrq(sysrq_xlate[KEY_B], false); | |
643 | ||
39030786 MP |
644 | if (sysrq_reset_downtime_ms) |
645 | mod_timer(&state->keyreset_timer, | |
646 | jiffies + msecs_to_jiffies(sysrq_reset_downtime_ms)); | |
647 | else | |
3d289517 | 648 | sysrq_do_reset((unsigned long)state); |
39030786 MP |
649 | } |
650 | ||
651 | static void sysrq_detect_reset_sequence(struct sysrq_state *state, | |
154b7a48 MP |
652 | unsigned int code, int value) |
653 | { | |
654 | if (!test_bit(code, state->reset_keybit)) { | |
655 | /* | |
656 | * Pressing any key _not_ in reset sequence cancels | |
39030786 MP |
657 | * the reset sequence. Also cancelling the timer in |
658 | * case additional keys were pressed after a reset | |
659 | * has been requested. | |
154b7a48 | 660 | */ |
39030786 | 661 | if (value && state->reset_seq_cnt) { |
154b7a48 | 662 | state->reset_canceled = true; |
39030786 MP |
663 | del_timer(&state->keyreset_timer); |
664 | } | |
154b7a48 | 665 | } else if (value == 0) { |
39030786 MP |
666 | /* |
667 | * Key release - all keys in the reset sequence need | |
668 | * to be pressed and held for the reset timeout | |
669 | * to hold. | |
670 | */ | |
671 | del_timer(&state->keyreset_timer); | |
672 | ||
154b7a48 MP |
673 | if (--state->reset_seq_cnt == 0) |
674 | state->reset_canceled = false; | |
675 | } else if (value == 1) { | |
676 | /* key press, not autorepeat */ | |
677 | if (++state->reset_seq_cnt == state->reset_seq_len && | |
678 | !state->reset_canceled) { | |
39030786 | 679 | sysrq_handle_reset_request(state); |
154b7a48 MP |
680 | } |
681 | } | |
154b7a48 MP |
682 | } |
683 | ||
fcb71930 DT |
684 | static void sysrq_reinject_alt_sysrq(struct work_struct *work) |
685 | { | |
686 | struct sysrq_state *sysrq = | |
687 | container_of(work, struct sysrq_state, reinject_work); | |
688 | struct input_handle *handle = &sysrq->handle; | |
689 | unsigned int alt_code = sysrq->alt_use; | |
690 | ||
691 | if (sysrq->need_reinject) { | |
7ab7b5ad DT |
692 | /* we do not want the assignment to be reordered */ |
693 | sysrq->reinjecting = true; | |
694 | mb(); | |
695 | ||
fcb71930 DT |
696 | /* Simulate press and release of Alt + SysRq */ |
697 | input_inject_event(handle, EV_KEY, alt_code, 1); | |
698 | input_inject_event(handle, EV_KEY, KEY_SYSRQ, 1); | |
699 | input_inject_event(handle, EV_SYN, SYN_REPORT, 1); | |
700 | ||
701 | input_inject_event(handle, EV_KEY, KEY_SYSRQ, 0); | |
702 | input_inject_event(handle, EV_KEY, alt_code, 0); | |
703 | input_inject_event(handle, EV_SYN, SYN_REPORT, 1); | |
7ab7b5ad DT |
704 | |
705 | mb(); | |
706 | sysrq->reinjecting = false; | |
fcb71930 DT |
707 | } |
708 | } | |
97f5f0cd | 709 | |
154b7a48 MP |
710 | static bool sysrq_handle_keypress(struct sysrq_state *sysrq, |
711 | unsigned int code, int value) | |
97f5f0cd | 712 | { |
fcb71930 | 713 | bool was_active = sysrq->active; |
1966cb22 DT |
714 | bool suppress; |
715 | ||
154b7a48 | 716 | switch (code) { |
7ab7b5ad | 717 | |
154b7a48 MP |
718 | case KEY_LEFTALT: |
719 | case KEY_RIGHTALT: | |
720 | if (!value) { | |
721 | /* One of ALTs is being released */ | |
722 | if (sysrq->active && code == sysrq->alt_use) | |
723 | sysrq->active = false; | |
1966cb22 | 724 | |
154b7a48 MP |
725 | sysrq->alt = KEY_RESERVED; |
726 | ||
727 | } else if (value != 2) { | |
728 | sysrq->alt = code; | |
729 | sysrq->need_reinject = false; | |
730 | } | |
fcb71930 | 731 | break; |
97f5f0cd | 732 | |
154b7a48 MP |
733 | case KEY_SYSRQ: |
734 | if (value == 1 && sysrq->alt != KEY_RESERVED) { | |
735 | sysrq->active = true; | |
736 | sysrq->alt_use = sysrq->alt; | |
737 | /* | |
738 | * If nothing else will be pressed we'll need | |
739 | * to re-inject Alt-SysRq keysroke. | |
740 | */ | |
741 | sysrq->need_reinject = true; | |
742 | } | |
97f5f0cd | 743 | |
154b7a48 MP |
744 | /* |
745 | * Pretend that sysrq was never pressed at all. This | |
746 | * is needed to properly handle KGDB which will try | |
747 | * to release all keys after exiting debugger. If we | |
748 | * do not clear key bit it KGDB will end up sending | |
749 | * release events for Alt and SysRq, potentially | |
750 | * triggering print screen function. | |
751 | */ | |
752 | if (sysrq->active) | |
753 | clear_bit(KEY_SYSRQ, sysrq->handle.dev->key); | |
f5dec511 | 754 | |
154b7a48 | 755 | break; |
fcb71930 | 756 | |
154b7a48 MP |
757 | default: |
758 | if (sysrq->active && value && value != 2) { | |
759 | sysrq->need_reinject = false; | |
760 | __handle_sysrq(sysrq_xlate[code], true); | |
761 | } | |
762 | break; | |
763 | } | |
fcb71930 | 764 | |
154b7a48 | 765 | suppress = sysrq->active; |
fcb71930 | 766 | |
154b7a48 | 767 | if (!sysrq->active) { |
fcb71930 | 768 | |
154b7a48 MP |
769 | /* |
770 | * See if reset sequence has changed since the last time. | |
771 | */ | |
772 | if (sysrq->reset_seq_version != sysrq_reset_seq_version) | |
773 | sysrq_parse_reset_sequence(sysrq); | |
fcb71930 | 774 | |
154b7a48 MP |
775 | /* |
776 | * If we are not suppressing key presses keep track of | |
777 | * keyboard state so we can release keys that have been | |
778 | * pressed before entering SysRq mode. | |
779 | */ | |
780 | if (value) | |
781 | set_bit(code, sysrq->key_down); | |
782 | else | |
783 | clear_bit(code, sysrq->key_down); | |
784 | ||
785 | if (was_active) | |
786 | schedule_work(&sysrq->reinject_work); | |
787 | ||
39030786 MP |
788 | /* Check for reset sequence */ |
789 | sysrq_detect_reset_sequence(sysrq, code, value); | |
97f5f0cd | 790 | |
154b7a48 MP |
791 | } else if (value == 0 && test_and_clear_bit(code, sysrq->key_down)) { |
792 | /* | |
793 | * Pass on release events for keys that was pressed before | |
794 | * entering SysRq mode. | |
795 | */ | |
796 | suppress = false; | |
797 | } | |
fcb71930 | 798 | |
154b7a48 MP |
799 | return suppress; |
800 | } | |
fcb71930 | 801 | |
154b7a48 MP |
802 | static bool sysrq_filter(struct input_handle *handle, |
803 | unsigned int type, unsigned int code, int value) | |
804 | { | |
805 | struct sysrq_state *sysrq = handle->private; | |
806 | bool suppress; | |
fcb71930 | 807 | |
154b7a48 MP |
808 | /* |
809 | * Do not filter anything if we are in the process of re-injecting | |
810 | * Alt+SysRq combination. | |
811 | */ | |
812 | if (sysrq->reinjecting) | |
813 | return false; | |
814 | ||
815 | switch (type) { | |
816 | ||
817 | case EV_SYN: | |
818 | suppress = false; | |
819 | break; | |
820 | ||
821 | case EV_KEY: | |
822 | suppress = sysrq_handle_keypress(sysrq, code, value); | |
97f5f0cd DT |
823 | break; |
824 | ||
825 | default: | |
fcb71930 | 826 | suppress = sysrq->active; |
97f5f0cd DT |
827 | break; |
828 | } | |
829 | ||
1966cb22 | 830 | return suppress; |
97f5f0cd DT |
831 | } |
832 | ||
833 | static int sysrq_connect(struct input_handler *handler, | |
834 | struct input_dev *dev, | |
835 | const struct input_device_id *id) | |
836 | { | |
fcb71930 | 837 | struct sysrq_state *sysrq; |
97f5f0cd DT |
838 | int error; |
839 | ||
fcb71930 DT |
840 | sysrq = kzalloc(sizeof(struct sysrq_state), GFP_KERNEL); |
841 | if (!sysrq) | |
97f5f0cd DT |
842 | return -ENOMEM; |
843 | ||
fcb71930 DT |
844 | INIT_WORK(&sysrq->reinject_work, sysrq_reinject_alt_sysrq); |
845 | ||
846 | sysrq->handle.dev = dev; | |
847 | sysrq->handle.handler = handler; | |
848 | sysrq->handle.name = "sysrq"; | |
849 | sysrq->handle.private = sysrq; | |
3d289517 MP |
850 | setup_timer(&sysrq->keyreset_timer, |
851 | sysrq_do_reset, (unsigned long)sysrq); | |
97f5f0cd | 852 | |
fcb71930 | 853 | error = input_register_handle(&sysrq->handle); |
97f5f0cd DT |
854 | if (error) { |
855 | pr_err("Failed to register input sysrq handler, error %d\n", | |
856 | error); | |
857 | goto err_free; | |
858 | } | |
859 | ||
fcb71930 | 860 | error = input_open_device(&sysrq->handle); |
97f5f0cd DT |
861 | if (error) { |
862 | pr_err("Failed to open input device, error %d\n", error); | |
863 | goto err_unregister; | |
864 | } | |
865 | ||
866 | return 0; | |
867 | ||
868 | err_unregister: | |
fcb71930 | 869 | input_unregister_handle(&sysrq->handle); |
97f5f0cd | 870 | err_free: |
fcb71930 | 871 | kfree(sysrq); |
97f5f0cd DT |
872 | return error; |
873 | } | |
874 | ||
875 | static void sysrq_disconnect(struct input_handle *handle) | |
876 | { | |
fcb71930 DT |
877 | struct sysrq_state *sysrq = handle->private; |
878 | ||
97f5f0cd | 879 | input_close_device(handle); |
fcb71930 | 880 | cancel_work_sync(&sysrq->reinject_work); |
39030786 | 881 | del_timer_sync(&sysrq->keyreset_timer); |
97f5f0cd | 882 | input_unregister_handle(handle); |
fcb71930 | 883 | kfree(sysrq); |
97f5f0cd DT |
884 | } |
885 | ||
886 | /* | |
1966cb22 DT |
887 | * We are matching on KEY_LEFTALT instead of KEY_SYSRQ because not all |
888 | * keyboards have SysRq key predefined and so user may add it to keymap | |
97f5f0cd DT |
889 | * later, but we expect all such keyboards to have left alt. |
890 | */ | |
891 | static const struct input_device_id sysrq_ids[] = { | |
892 | { | |
893 | .flags = INPUT_DEVICE_ID_MATCH_EVBIT | | |
894 | INPUT_DEVICE_ID_MATCH_KEYBIT, | |
895 | .evbit = { BIT_MASK(EV_KEY) }, | |
896 | .keybit = { BIT_MASK(KEY_LEFTALT) }, | |
897 | }, | |
898 | { }, | |
899 | }; | |
900 | ||
901 | static struct input_handler sysrq_handler = { | |
902 | .filter = sysrq_filter, | |
903 | .connect = sysrq_connect, | |
904 | .disconnect = sysrq_disconnect, | |
905 | .name = "sysrq", | |
906 | .id_table = sysrq_ids, | |
907 | }; | |
908 | ||
909 | static bool sysrq_handler_registered; | |
910 | ||
911 | static inline void sysrq_register_handler(void) | |
912 | { | |
154b7a48 | 913 | unsigned short key; |
97f5f0cd | 914 | int error; |
154b7a48 MP |
915 | int i; |
916 | ||
adf96e6f LT |
917 | for (i = 0; i < ARRAY_SIZE(sysrq_reset_seq); i++) { |
918 | key = platform_sysrq_reset_seq[i]; | |
919 | if (key == KEY_RESERVED || key > KEY_MAX) | |
920 | break; | |
154b7a48 | 921 | |
adf96e6f | 922 | sysrq_reset_seq[sysrq_reset_seq_len++] = key; |
154b7a48 | 923 | } |
97f5f0cd DT |
924 | |
925 | error = input_register_handler(&sysrq_handler); | |
926 | if (error) | |
927 | pr_err("Failed to register input handler, error %d", error); | |
928 | else | |
929 | sysrq_handler_registered = true; | |
930 | } | |
931 | ||
932 | static inline void sysrq_unregister_handler(void) | |
933 | { | |
934 | if (sysrq_handler_registered) { | |
935 | input_unregister_handler(&sysrq_handler); | |
936 | sysrq_handler_registered = false; | |
937 | } | |
938 | } | |
939 | ||
154b7a48 MP |
940 | static int sysrq_reset_seq_param_set(const char *buffer, |
941 | const struct kernel_param *kp) | |
942 | { | |
943 | unsigned long val; | |
944 | int error; | |
945 | ||
86b40567 | 946 | error = kstrtoul(buffer, 0, &val); |
154b7a48 MP |
947 | if (error < 0) |
948 | return error; | |
949 | ||
950 | if (val > KEY_MAX) | |
951 | return -EINVAL; | |
952 | ||
953 | *((unsigned short *)kp->arg) = val; | |
954 | sysrq_reset_seq_version++; | |
955 | ||
956 | return 0; | |
957 | } | |
958 | ||
959 | static struct kernel_param_ops param_ops_sysrq_reset_seq = { | |
960 | .get = param_get_ushort, | |
961 | .set = sysrq_reset_seq_param_set, | |
962 | }; | |
963 | ||
964 | #define param_check_sysrq_reset_seq(name, p) \ | |
965 | __param_check(name, p, unsigned short) | |
966 | ||
967 | module_param_array_named(reset_seq, sysrq_reset_seq, sysrq_reset_seq, | |
968 | &sysrq_reset_seq_len, 0644); | |
969 | ||
39030786 MP |
970 | module_param_named(sysrq_downtime_ms, sysrq_reset_downtime_ms, int, 0644); |
971 | ||
97f5f0cd DT |
972 | #else |
973 | ||
974 | static inline void sysrq_register_handler(void) | |
975 | { | |
976 | } | |
977 | ||
978 | static inline void sysrq_unregister_handler(void) | |
979 | { | |
980 | } | |
981 | ||
982 | #endif /* CONFIG_INPUT */ | |
983 | ||
984 | int sysrq_toggle_support(int enable_mask) | |
985 | { | |
986 | bool was_enabled = sysrq_on(); | |
987 | ||
988 | sysrq_enabled = enable_mask; | |
989 | ||
990 | if (was_enabled != sysrq_on()) { | |
991 | if (sysrq_on()) | |
992 | sysrq_register_handler(); | |
993 | else | |
994 | sysrq_unregister_handler(); | |
995 | } | |
996 | ||
997 | return 0; | |
998 | } | |
999 | ||
cf62ddce | 1000 | static int __sysrq_swap_key_ops(int key, struct sysrq_key_op *insert_op_p, |
bf36b901 AM |
1001 | struct sysrq_key_op *remove_op_p) |
1002 | { | |
1da177e4 LT |
1003 | int retval; |
1004 | unsigned long flags; | |
1005 | ||
1006 | spin_lock_irqsave(&sysrq_key_table_lock, flags); | |
1007 | if (__sysrq_get_key_op(key) == remove_op_p) { | |
1008 | __sysrq_put_key_op(key, insert_op_p); | |
1009 | retval = 0; | |
1010 | } else { | |
1011 | retval = -1; | |
1012 | } | |
1013 | spin_unlock_irqrestore(&sysrq_key_table_lock, flags); | |
1da177e4 LT |
1014 | return retval; |
1015 | } | |
1016 | ||
1017 | int register_sysrq_key(int key, struct sysrq_key_op *op_p) | |
1018 | { | |
1019 | return __sysrq_swap_key_ops(key, op_p, NULL); | |
1020 | } | |
bf36b901 | 1021 | EXPORT_SYMBOL(register_sysrq_key); |
1da177e4 LT |
1022 | |
1023 | int unregister_sysrq_key(int key, struct sysrq_key_op *op_p) | |
1024 | { | |
1025 | return __sysrq_swap_key_ops(key, NULL, op_p); | |
1026 | } | |
1da177e4 | 1027 | EXPORT_SYMBOL(unregister_sysrq_key); |
f40cbaa5 AD |
1028 | |
1029 | #ifdef CONFIG_PROC_FS | |
1030 | /* | |
1031 | * writing 'C' to /proc/sysrq-trigger is like sysrq-C | |
1032 | */ | |
1033 | static ssize_t write_sysrq_trigger(struct file *file, const char __user *buf, | |
1034 | size_t count, loff_t *ppos) | |
1035 | { | |
1036 | if (count) { | |
1037 | char c; | |
1038 | ||
1039 | if (get_user(c, buf)) | |
1040 | return -EFAULT; | |
f335397d | 1041 | __handle_sysrq(c, false); |
f40cbaa5 | 1042 | } |
97f5f0cd | 1043 | |
f40cbaa5 AD |
1044 | return count; |
1045 | } | |
1046 | ||
1047 | static const struct file_operations proc_sysrq_trigger_operations = { | |
1048 | .write = write_sysrq_trigger, | |
6038f373 | 1049 | .llseek = noop_llseek, |
f40cbaa5 AD |
1050 | }; |
1051 | ||
97f5f0cd DT |
1052 | static void sysrq_init_procfs(void) |
1053 | { | |
1054 | if (!proc_create("sysrq-trigger", S_IWUSR, NULL, | |
1055 | &proc_sysrq_trigger_operations)) | |
1056 | pr_err("Failed to register proc interface\n"); | |
1057 | } | |
1058 | ||
1059 | #else | |
1060 | ||
1061 | static inline void sysrq_init_procfs(void) | |
1062 | { | |
1063 | } | |
1064 | ||
1065 | #endif /* CONFIG_PROC_FS */ | |
1066 | ||
f40cbaa5 AD |
1067 | static int __init sysrq_init(void) |
1068 | { | |
97f5f0cd DT |
1069 | sysrq_init_procfs(); |
1070 | ||
1071 | if (sysrq_on()) | |
1072 | sysrq_register_handler(); | |
1073 | ||
f40cbaa5 AD |
1074 | return 0; |
1075 | } | |
1076 | module_init(sysrq_init); |