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Commit | Line | Data |
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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> |
4c076eb0 | 48 | #include <linux/of.h> |
1da177e4 LT |
49 | |
50 | #include <asm/ptrace.h> | |
2033b0c3 | 51 | #include <asm/irq_regs.h> |
1da177e4 LT |
52 | |
53 | /* Whether we react on sysrq keys or just ignore them */ | |
8c6a98b2 | 54 | static int __read_mostly sysrq_enabled = SYSRQ_DEFAULT_ENABLE; |
97f5f0cd | 55 | static bool __read_mostly sysrq_always_enabled; |
5d6f647f | 56 | |
39030786 MP |
57 | unsigned short platform_sysrq_reset_seq[] __weak = { KEY_RESERVED }; |
58 | int sysrq_reset_downtime_ms __weak; | |
59 | ||
97f5f0cd | 60 | static bool sysrq_on(void) |
5d6f647f | 61 | { |
97f5f0cd | 62 | return sysrq_enabled || sysrq_always_enabled; |
5d6f647f IM |
63 | } |
64 | ||
65 | /* | |
66 | * A value of 1 means 'all', other nonzero values are an op mask: | |
67 | */ | |
97f5f0cd | 68 | static bool sysrq_on_mask(int mask) |
5d6f647f | 69 | { |
97f5f0cd DT |
70 | return sysrq_always_enabled || |
71 | sysrq_enabled == 1 || | |
72 | (sysrq_enabled & mask); | |
5d6f647f IM |
73 | } |
74 | ||
75 | static int __init sysrq_always_enabled_setup(char *str) | |
76 | { | |
97f5f0cd DT |
77 | sysrq_always_enabled = true; |
78 | pr_info("sysrq always enabled.\n"); | |
5d6f647f IM |
79 | |
80 | return 1; | |
81 | } | |
82 | ||
83 | __setup("sysrq_always_enabled", sysrq_always_enabled_setup); | |
84 | ||
1da177e4 | 85 | |
1495cc9d | 86 | static void sysrq_handle_loglevel(int key) |
1da177e4 LT |
87 | { |
88 | int i; | |
97f5f0cd | 89 | |
1da177e4 LT |
90 | i = key - '0'; |
91 | console_loglevel = 7; | |
92 | printk("Loglevel set to %d\n", i); | |
93 | console_loglevel = i; | |
bf36b901 | 94 | } |
1da177e4 LT |
95 | static struct sysrq_key_op sysrq_loglevel_op = { |
96 | .handler = sysrq_handle_loglevel, | |
208b95ce | 97 | .help_msg = "loglevel(0-9)", |
1da177e4 LT |
98 | .action_msg = "Changing Loglevel", |
99 | .enable_mask = SYSRQ_ENABLE_LOG, | |
100 | }; | |
101 | ||
1da177e4 | 102 | #ifdef CONFIG_VT |
1495cc9d | 103 | static void sysrq_handle_SAK(int key) |
1da177e4 | 104 | { |
8b6312f4 | 105 | struct work_struct *SAK_work = &vc_cons[fg_console].SAK_work; |
8b6312f4 | 106 | schedule_work(SAK_work); |
1da177e4 LT |
107 | } |
108 | static struct sysrq_key_op sysrq_SAK_op = { | |
109 | .handler = sysrq_handle_SAK, | |
afa80ccb | 110 | .help_msg = "sak(k)", |
1da177e4 LT |
111 | .action_msg = "SAK", |
112 | .enable_mask = SYSRQ_ENABLE_KEYBOARD, | |
113 | }; | |
bf36b901 | 114 | #else |
97f5f0cd | 115 | #define sysrq_SAK_op (*(struct sysrq_key_op *)NULL) |
1da177e4 LT |
116 | #endif |
117 | ||
118 | #ifdef CONFIG_VT | |
1495cc9d | 119 | static void sysrq_handle_unraw(int key) |
1da177e4 | 120 | { |
079c9534 | 121 | vt_reset_unicode(fg_console); |
1da177e4 | 122 | } |
079c9534 | 123 | |
1da177e4 LT |
124 | static struct sysrq_key_op sysrq_unraw_op = { |
125 | .handler = sysrq_handle_unraw, | |
afa80ccb | 126 | .help_msg = "unraw(r)", |
2e8ecb9d | 127 | .action_msg = "Keyboard mode set to system default", |
1da177e4 LT |
128 | .enable_mask = SYSRQ_ENABLE_KEYBOARD, |
129 | }; | |
bf36b901 | 130 | #else |
97f5f0cd | 131 | #define sysrq_unraw_op (*(struct sysrq_key_op *)NULL) |
1da177e4 LT |
132 | #endif /* CONFIG_VT */ |
133 | ||
1495cc9d | 134 | static void sysrq_handle_crash(int key) |
86b1ae38 | 135 | { |
d6580a9f | 136 | char *killer = NULL; |
cab8bd34 HS |
137 | |
138 | panic_on_oops = 1; /* force panic */ | |
139 | wmb(); | |
d6580a9f | 140 | *killer = 1; |
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 RR |
210 | #ifdef CONFIG_SMP |
211 | static DEFINE_SPINLOCK(show_lock); | |
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 | ||
221 | spin_lock_irqsave(&show_lock, flags); | |
222 | printk(KERN_INFO "CPU%d:\n", smp_processor_id()); | |
223 | show_stack(NULL, NULL); | |
224 | spin_unlock_irqrestore(&show_lock, flags); | |
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()) { | |
242 | struct pt_regs *regs = get_irq_regs(); | |
243 | ||
244 | if (regs) { | |
245 | printk(KERN_INFO "CPU%d:\n", smp_processor_id()); | |
246 | show_regs(regs); | |
247 | } | |
248 | schedule_work(&sysrq_showallcpus); | |
249 | } | |
5045bcae RR |
250 | } |
251 | ||
252 | static struct sysrq_key_op sysrq_showallcpus_op = { | |
253 | .handler = sysrq_handle_showallcpus, | |
afa80ccb | 254 | .help_msg = "show-backtrace-all-active-cpus(l)", |
5045bcae RR |
255 | .action_msg = "Show backtrace of all active CPUs", |
256 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
257 | }; | |
258 | #endif | |
259 | ||
1495cc9d | 260 | static void sysrq_handle_showregs(int key) |
1da177e4 | 261 | { |
7d12e780 DH |
262 | struct pt_regs *regs = get_irq_regs(); |
263 | if (regs) | |
264 | show_regs(regs); | |
cdd6c482 | 265 | perf_event_print_debug(); |
1da177e4 LT |
266 | } |
267 | static struct sysrq_key_op sysrq_showregs_op = { | |
268 | .handler = sysrq_handle_showregs, | |
afa80ccb | 269 | .help_msg = "show-registers(p)", |
1da177e4 LT |
270 | .action_msg = "Show Regs", |
271 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
272 | }; | |
273 | ||
1495cc9d | 274 | static void sysrq_handle_showstate(int key) |
1da177e4 LT |
275 | { |
276 | show_state(); | |
277 | } | |
278 | static struct sysrq_key_op sysrq_showstate_op = { | |
279 | .handler = sysrq_handle_showstate, | |
afa80ccb | 280 | .help_msg = "show-task-states(t)", |
1da177e4 LT |
281 | .action_msg = "Show State", |
282 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
283 | }; | |
284 | ||
1495cc9d | 285 | static void sysrq_handle_showstate_blocked(int key) |
e59e2ae2 IM |
286 | { |
287 | show_state_filter(TASK_UNINTERRUPTIBLE); | |
288 | } | |
289 | static struct sysrq_key_op sysrq_showstate_blocked_op = { | |
290 | .handler = sysrq_handle_showstate_blocked, | |
afa80ccb | 291 | .help_msg = "show-blocked-tasks(w)", |
e59e2ae2 IM |
292 | .action_msg = "Show Blocked State", |
293 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
294 | }; | |
295 | ||
69f698ad PZ |
296 | #ifdef CONFIG_TRACING |
297 | #include <linux/ftrace.h> | |
298 | ||
1495cc9d | 299 | static void sysrq_ftrace_dump(int key) |
69f698ad | 300 | { |
cecbca96 | 301 | ftrace_dump(DUMP_ALL); |
69f698ad PZ |
302 | } |
303 | static struct sysrq_key_op sysrq_ftrace_dump_op = { | |
304 | .handler = sysrq_ftrace_dump, | |
afa80ccb | 305 | .help_msg = "dump-ftrace-buffer(z)", |
69f698ad PZ |
306 | .action_msg = "Dump ftrace buffer", |
307 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
308 | }; | |
309 | #else | |
97f5f0cd | 310 | #define sysrq_ftrace_dump_op (*(struct sysrq_key_op *)NULL) |
69f698ad | 311 | #endif |
e59e2ae2 | 312 | |
1495cc9d | 313 | static void sysrq_handle_showmem(int key) |
1da177e4 | 314 | { |
b2b755b5 | 315 | show_mem(0); |
1da177e4 LT |
316 | } |
317 | static struct sysrq_key_op sysrq_showmem_op = { | |
318 | .handler = sysrq_handle_showmem, | |
afa80ccb | 319 | .help_msg = "show-memory-usage(m)", |
1da177e4 LT |
320 | .action_msg = "Show Memory", |
321 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
322 | }; | |
323 | ||
bf36b901 AM |
324 | /* |
325 | * Signal sysrq helper function. Sends a signal to all user processes. | |
326 | */ | |
1da177e4 LT |
327 | static void send_sig_all(int sig) |
328 | { | |
329 | struct task_struct *p; | |
330 | ||
e502babe | 331 | read_lock(&tasklist_lock); |
1da177e4 | 332 | for_each_process(p) { |
d3a532a9 AV |
333 | if (p->flags & PF_KTHREAD) |
334 | continue; | |
335 | if (is_global_init(p)) | |
336 | continue; | |
337 | ||
b82c3287 | 338 | do_send_sig_info(sig, SEND_SIG_FORCED, p, true); |
1da177e4 | 339 | } |
e502babe | 340 | read_unlock(&tasklist_lock); |
1da177e4 LT |
341 | } |
342 | ||
1495cc9d | 343 | static void sysrq_handle_term(int key) |
1da177e4 LT |
344 | { |
345 | send_sig_all(SIGTERM); | |
346 | console_loglevel = 8; | |
347 | } | |
348 | static struct sysrq_key_op sysrq_term_op = { | |
349 | .handler = sysrq_handle_term, | |
afa80ccb | 350 | .help_msg = "terminate-all-tasks(e)", |
1da177e4 LT |
351 | .action_msg = "Terminate All Tasks", |
352 | .enable_mask = SYSRQ_ENABLE_SIGNAL, | |
353 | }; | |
354 | ||
65f27f38 | 355 | static void moom_callback(struct work_struct *ignored) |
1da177e4 | 356 | { |
53186095 DR |
357 | out_of_memory(node_zonelist(first_online_node, GFP_KERNEL), GFP_KERNEL, |
358 | 0, NULL, true); | |
1da177e4 LT |
359 | } |
360 | ||
65f27f38 | 361 | static DECLARE_WORK(moom_work, moom_callback); |
1da177e4 | 362 | |
1495cc9d | 363 | static void sysrq_handle_moom(int key) |
1da177e4 LT |
364 | { |
365 | schedule_work(&moom_work); | |
366 | } | |
367 | static struct sysrq_key_op sysrq_moom_op = { | |
368 | .handler = sysrq_handle_moom, | |
afa80ccb | 369 | .help_msg = "memory-full-oom-kill(f)", |
1da177e4 | 370 | .action_msg = "Manual OOM execution", |
b4236f81 | 371 | .enable_mask = SYSRQ_ENABLE_SIGNAL, |
1da177e4 LT |
372 | }; |
373 | ||
c2d75438 | 374 | #ifdef CONFIG_BLOCK |
1495cc9d | 375 | static void sysrq_handle_thaw(int key) |
c2d75438 ES |
376 | { |
377 | emergency_thaw_all(); | |
378 | } | |
379 | static struct sysrq_key_op sysrq_thaw_op = { | |
380 | .handler = sysrq_handle_thaw, | |
afa80ccb | 381 | .help_msg = "thaw-filesystems(j)", |
c2d75438 ES |
382 | .action_msg = "Emergency Thaw of all frozen filesystems", |
383 | .enable_mask = SYSRQ_ENABLE_SIGNAL, | |
384 | }; | |
385 | #endif | |
386 | ||
1495cc9d | 387 | static void sysrq_handle_kill(int key) |
1da177e4 LT |
388 | { |
389 | send_sig_all(SIGKILL); | |
390 | console_loglevel = 8; | |
391 | } | |
392 | static struct sysrq_key_op sysrq_kill_op = { | |
393 | .handler = sysrq_handle_kill, | |
afa80ccb | 394 | .help_msg = "kill-all-tasks(i)", |
1da177e4 LT |
395 | .action_msg = "Kill All Tasks", |
396 | .enable_mask = SYSRQ_ENABLE_SIGNAL, | |
397 | }; | |
398 | ||
1495cc9d | 399 | static void sysrq_handle_unrt(int key) |
1da177e4 LT |
400 | { |
401 | normalize_rt_tasks(); | |
402 | } | |
403 | static struct sysrq_key_op sysrq_unrt_op = { | |
404 | .handler = sysrq_handle_unrt, | |
afa80ccb | 405 | .help_msg = "nice-all-RT-tasks(n)", |
1da177e4 LT |
406 | .action_msg = "Nice All RT Tasks", |
407 | .enable_mask = SYSRQ_ENABLE_RTNICE, | |
408 | }; | |
409 | ||
410 | /* Key Operations table and lock */ | |
411 | static DEFINE_SPINLOCK(sysrq_key_table_lock); | |
bf36b901 AM |
412 | |
413 | static struct sysrq_key_op *sysrq_key_table[36] = { | |
414 | &sysrq_loglevel_op, /* 0 */ | |
415 | &sysrq_loglevel_op, /* 1 */ | |
416 | &sysrq_loglevel_op, /* 2 */ | |
417 | &sysrq_loglevel_op, /* 3 */ | |
418 | &sysrq_loglevel_op, /* 4 */ | |
419 | &sysrq_loglevel_op, /* 5 */ | |
420 | &sysrq_loglevel_op, /* 6 */ | |
421 | &sysrq_loglevel_op, /* 7 */ | |
422 | &sysrq_loglevel_op, /* 8 */ | |
423 | &sysrq_loglevel_op, /* 9 */ | |
424 | ||
425 | /* | |
d346cce3 RD |
426 | * a: Don't use for system provided sysrqs, it is handled specially on |
427 | * sparc and will never arrive. | |
bf36b901 AM |
428 | */ |
429 | NULL, /* a */ | |
430 | &sysrq_reboot_op, /* b */ | |
cab8bd34 | 431 | &sysrq_crash_op, /* c & ibm_emac driver debug */ |
bf36b901 AM |
432 | &sysrq_showlocks_op, /* d */ |
433 | &sysrq_term_op, /* e */ | |
434 | &sysrq_moom_op, /* f */ | |
364b5b7b | 435 | /* g: May be registered for the kernel debugger */ |
bf36b901 | 436 | NULL, /* g */ |
c2d75438 | 437 | NULL, /* h - reserved for help */ |
bf36b901 | 438 | &sysrq_kill_op, /* i */ |
c2d75438 ES |
439 | #ifdef CONFIG_BLOCK |
440 | &sysrq_thaw_op, /* j */ | |
441 | #else | |
bf36b901 | 442 | NULL, /* j */ |
c2d75438 | 443 | #endif |
bf36b901 | 444 | &sysrq_SAK_op, /* k */ |
5045bcae RR |
445 | #ifdef CONFIG_SMP |
446 | &sysrq_showallcpus_op, /* l */ | |
447 | #else | |
bf36b901 | 448 | NULL, /* l */ |
5045bcae | 449 | #endif |
bf36b901 AM |
450 | &sysrq_showmem_op, /* m */ |
451 | &sysrq_unrt_op, /* n */ | |
d346cce3 | 452 | /* o: This will often be registered as 'Off' at init time */ |
bf36b901 AM |
453 | NULL, /* o */ |
454 | &sysrq_showregs_op, /* p */ | |
88ad0bf6 | 455 | &sysrq_show_timers_op, /* q */ |
d346cce3 | 456 | &sysrq_unraw_op, /* r */ |
bf36b901 AM |
457 | &sysrq_sync_op, /* s */ |
458 | &sysrq_showstate_op, /* t */ | |
459 | &sysrq_mountro_op, /* u */ | |
364b5b7b | 460 | /* v: May be registered for frame buffer console restore */ |
bf36b901 | 461 | NULL, /* v */ |
d346cce3 RD |
462 | &sysrq_showstate_blocked_op, /* w */ |
463 | /* x: May be registered on ppc/powerpc for xmon */ | |
916ca14a | 464 | /* x: May be registered on sparc64 for global PMU dump */ |
d346cce3 | 465 | NULL, /* x */ |
93dae5b7 | 466 | /* y: May be registered on sparc64 for global register dump */ |
bf36b901 | 467 | NULL, /* y */ |
69f698ad | 468 | &sysrq_ftrace_dump_op, /* z */ |
1da177e4 LT |
469 | }; |
470 | ||
471 | /* key2index calculation, -1 on invalid index */ | |
bf36b901 AM |
472 | static int sysrq_key_table_key2index(int key) |
473 | { | |
1da177e4 | 474 | int retval; |
bf36b901 AM |
475 | |
476 | if ((key >= '0') && (key <= '9')) | |
1da177e4 | 477 | retval = key - '0'; |
bf36b901 | 478 | else if ((key >= 'a') && (key <= 'z')) |
1da177e4 | 479 | retval = key + 10 - 'a'; |
bf36b901 | 480 | else |
1da177e4 | 481 | retval = -1; |
1da177e4 LT |
482 | return retval; |
483 | } | |
484 | ||
485 | /* | |
486 | * get and put functions for the table, exposed to modules. | |
487 | */ | |
bf36b901 AM |
488 | struct sysrq_key_op *__sysrq_get_key_op(int key) |
489 | { | |
490 | struct sysrq_key_op *op_p = NULL; | |
1da177e4 | 491 | int i; |
bf36b901 | 492 | |
1da177e4 | 493 | i = sysrq_key_table_key2index(key); |
bf36b901 AM |
494 | if (i != -1) |
495 | op_p = sysrq_key_table[i]; | |
97f5f0cd | 496 | |
1da177e4 LT |
497 | return op_p; |
498 | } | |
499 | ||
bf36b901 AM |
500 | static void __sysrq_put_key_op(int key, struct sysrq_key_op *op_p) |
501 | { | |
502 | int i = sysrq_key_table_key2index(key); | |
1da177e4 | 503 | |
1da177e4 LT |
504 | if (i != -1) |
505 | sysrq_key_table[i] = op_p; | |
506 | } | |
507 | ||
f335397d | 508 | void __handle_sysrq(int key, bool check_mask) |
1da177e4 LT |
509 | { |
510 | struct sysrq_key_op *op_p; | |
511 | int orig_log_level; | |
bf36b901 | 512 | int i; |
1da177e4 LT |
513 | unsigned long flags; |
514 | ||
515 | spin_lock_irqsave(&sysrq_key_table_lock, flags); | |
fb144adc AW |
516 | /* |
517 | * Raise the apparent loglevel to maximum so that the sysrq header | |
518 | * is shown to provide the user with positive feedback. We do not | |
519 | * simply emit this at KERN_EMERG as that would change message | |
520 | * routing in the consumers of /proc/kmsg. | |
521 | */ | |
1da177e4 LT |
522 | orig_log_level = console_loglevel; |
523 | console_loglevel = 7; | |
524 | printk(KERN_INFO "SysRq : "); | |
525 | ||
526 | op_p = __sysrq_get_key_op(key); | |
527 | if (op_p) { | |
bf36b901 AM |
528 | /* |
529 | * Should we check for enabled operations (/proc/sysrq-trigger | |
530 | * should not) and is the invoked operation enabled? | |
531 | */ | |
5d6f647f | 532 | if (!check_mask || sysrq_on_mask(op_p->enable_mask)) { |
bf36b901 | 533 | printk("%s\n", op_p->action_msg); |
1da177e4 | 534 | console_loglevel = orig_log_level; |
1495cc9d | 535 | op_p->handler(key); |
bf36b901 | 536 | } else { |
1da177e4 | 537 | printk("This sysrq operation is disabled.\n"); |
bf36b901 | 538 | } |
1da177e4 LT |
539 | } else { |
540 | printk("HELP : "); | |
541 | /* Only print the help msg once per handler */ | |
bf36b901 AM |
542 | for (i = 0; i < ARRAY_SIZE(sysrq_key_table); i++) { |
543 | if (sysrq_key_table[i]) { | |
544 | int j; | |
545 | ||
546 | for (j = 0; sysrq_key_table[i] != | |
547 | sysrq_key_table[j]; j++) | |
548 | ; | |
549 | if (j != i) | |
550 | continue; | |
551 | printk("%s ", sysrq_key_table[i]->help_msg); | |
552 | } | |
1da177e4 | 553 | } |
bf36b901 | 554 | printk("\n"); |
1da177e4 LT |
555 | console_loglevel = orig_log_level; |
556 | } | |
557 | spin_unlock_irqrestore(&sysrq_key_table_lock, flags); | |
558 | } | |
559 | ||
f335397d | 560 | void handle_sysrq(int key) |
1da177e4 | 561 | { |
5d6f647f | 562 | if (sysrq_on()) |
f335397d | 563 | __handle_sysrq(key, true); |
1da177e4 | 564 | } |
bf36b901 | 565 | EXPORT_SYMBOL(handle_sysrq); |
1da177e4 | 566 | |
97f5f0cd DT |
567 | #ifdef CONFIG_INPUT |
568 | ||
569 | /* Simple translation table for the SysRq keys */ | |
fcb71930 | 570 | static const unsigned char sysrq_xlate[KEY_CNT] = |
97f5f0cd DT |
571 | "\000\0331234567890-=\177\t" /* 0x00 - 0x0f */ |
572 | "qwertyuiop[]\r\000as" /* 0x10 - 0x1f */ | |
573 | "dfghjkl;'`\000\\zxcv" /* 0x20 - 0x2f */ | |
574 | "bnm,./\000*\000 \000\201\202\203\204\205" /* 0x30 - 0x3f */ | |
575 | "\206\207\210\211\212\000\000789-456+1" /* 0x40 - 0x4f */ | |
576 | "230\177\000\000\213\214\000\000\000\000\000\000\000\000\000\000" /* 0x50 - 0x5f */ | |
577 | "\r\000/"; /* 0x60 - 0x6f */ | |
578 | ||
fcb71930 DT |
579 | struct sysrq_state { |
580 | struct input_handle handle; | |
581 | struct work_struct reinject_work; | |
582 | unsigned long key_down[BITS_TO_LONGS(KEY_CNT)]; | |
583 | unsigned int alt; | |
584 | unsigned int alt_use; | |
585 | bool active; | |
586 | bool need_reinject; | |
7ab7b5ad | 587 | bool reinjecting; |
154b7a48 MP |
588 | |
589 | /* reset sequence handling */ | |
590 | bool reset_canceled; | |
3d289517 | 591 | bool reset_requested; |
154b7a48 MP |
592 | unsigned long reset_keybit[BITS_TO_LONGS(KEY_CNT)]; |
593 | int reset_seq_len; | |
594 | int reset_seq_cnt; | |
595 | int reset_seq_version; | |
39030786 | 596 | struct timer_list keyreset_timer; |
fcb71930 DT |
597 | }; |
598 | ||
154b7a48 MP |
599 | #define SYSRQ_KEY_RESET_MAX 20 /* Should be plenty */ |
600 | static unsigned short sysrq_reset_seq[SYSRQ_KEY_RESET_MAX]; | |
601 | static unsigned int sysrq_reset_seq_len; | |
602 | static unsigned int sysrq_reset_seq_version = 1; | |
603 | ||
604 | static void sysrq_parse_reset_sequence(struct sysrq_state *state) | |
605 | { | |
606 | int i; | |
607 | unsigned short key; | |
608 | ||
609 | state->reset_seq_cnt = 0; | |
610 | ||
611 | for (i = 0; i < sysrq_reset_seq_len; i++) { | |
612 | key = sysrq_reset_seq[i]; | |
613 | ||
614 | if (key == KEY_RESERVED || key > KEY_MAX) | |
615 | break; | |
616 | ||
617 | __set_bit(key, state->reset_keybit); | |
618 | state->reset_seq_len++; | |
619 | ||
620 | if (test_bit(key, state->key_down)) | |
621 | state->reset_seq_cnt++; | |
622 | } | |
623 | ||
624 | /* Disable reset until old keys are not released */ | |
625 | state->reset_canceled = state->reset_seq_cnt != 0; | |
626 | ||
627 | state->reset_seq_version = sysrq_reset_seq_version; | |
628 | } | |
629 | ||
3d289517 | 630 | static void sysrq_do_reset(unsigned long _state) |
39030786 | 631 | { |
3d289517 MP |
632 | struct sysrq_state *state = (struct sysrq_state *) _state; |
633 | ||
634 | state->reset_requested = true; | |
635 | ||
636 | sys_sync(); | |
637 | kernel_restart(NULL); | |
39030786 MP |
638 | } |
639 | ||
640 | static void sysrq_handle_reset_request(struct sysrq_state *state) | |
641 | { | |
3d289517 MP |
642 | if (state->reset_requested) |
643 | __handle_sysrq(sysrq_xlate[KEY_B], false); | |
644 | ||
39030786 MP |
645 | if (sysrq_reset_downtime_ms) |
646 | mod_timer(&state->keyreset_timer, | |
647 | jiffies + msecs_to_jiffies(sysrq_reset_downtime_ms)); | |
648 | else | |
3d289517 | 649 | sysrq_do_reset((unsigned long)state); |
39030786 MP |
650 | } |
651 | ||
652 | static void sysrq_detect_reset_sequence(struct sysrq_state *state, | |
154b7a48 MP |
653 | unsigned int code, int value) |
654 | { | |
655 | if (!test_bit(code, state->reset_keybit)) { | |
656 | /* | |
657 | * Pressing any key _not_ in reset sequence cancels | |
39030786 MP |
658 | * the reset sequence. Also cancelling the timer in |
659 | * case additional keys were pressed after a reset | |
660 | * has been requested. | |
154b7a48 | 661 | */ |
39030786 | 662 | if (value && state->reset_seq_cnt) { |
154b7a48 | 663 | state->reset_canceled = true; |
39030786 MP |
664 | del_timer(&state->keyreset_timer); |
665 | } | |
154b7a48 | 666 | } else if (value == 0) { |
39030786 MP |
667 | /* |
668 | * Key release - all keys in the reset sequence need | |
669 | * to be pressed and held for the reset timeout | |
670 | * to hold. | |
671 | */ | |
672 | del_timer(&state->keyreset_timer); | |
673 | ||
154b7a48 MP |
674 | if (--state->reset_seq_cnt == 0) |
675 | state->reset_canceled = false; | |
676 | } else if (value == 1) { | |
677 | /* key press, not autorepeat */ | |
678 | if (++state->reset_seq_cnt == state->reset_seq_len && | |
679 | !state->reset_canceled) { | |
39030786 | 680 | sysrq_handle_reset_request(state); |
154b7a48 MP |
681 | } |
682 | } | |
154b7a48 MP |
683 | } |
684 | ||
4c076eb0 MP |
685 | #ifdef CONFIG_OF |
686 | static void sysrq_of_get_keyreset_config(void) | |
687 | { | |
688 | u32 key; | |
689 | struct device_node *np; | |
690 | struct property *prop; | |
691 | const __be32 *p; | |
692 | ||
693 | np = of_find_node_by_path("/chosen/linux,sysrq-reset-seq"); | |
694 | if (!np) { | |
695 | pr_debug("No sysrq node found"); | |
696 | return; | |
697 | } | |
698 | ||
699 | /* Reset in case a __weak definition was present */ | |
700 | sysrq_reset_seq_len = 0; | |
701 | ||
702 | of_property_for_each_u32(np, "keyset", prop, p, key) { | |
703 | if (key == KEY_RESERVED || key > KEY_MAX || | |
704 | sysrq_reset_seq_len == SYSRQ_KEY_RESET_MAX) | |
705 | break; | |
706 | ||
707 | sysrq_reset_seq[sysrq_reset_seq_len++] = (unsigned short)key; | |
708 | } | |
709 | ||
710 | /* Get reset timeout if any. */ | |
711 | of_property_read_u32(np, "timeout-ms", &sysrq_reset_downtime_ms); | |
712 | } | |
713 | #else | |
714 | static void sysrq_of_get_keyreset_config(void) | |
715 | { | |
716 | } | |
717 | #endif | |
718 | ||
fcb71930 DT |
719 | static void sysrq_reinject_alt_sysrq(struct work_struct *work) |
720 | { | |
721 | struct sysrq_state *sysrq = | |
722 | container_of(work, struct sysrq_state, reinject_work); | |
723 | struct input_handle *handle = &sysrq->handle; | |
724 | unsigned int alt_code = sysrq->alt_use; | |
725 | ||
726 | if (sysrq->need_reinject) { | |
7ab7b5ad DT |
727 | /* we do not want the assignment to be reordered */ |
728 | sysrq->reinjecting = true; | |
729 | mb(); | |
730 | ||
fcb71930 DT |
731 | /* Simulate press and release of Alt + SysRq */ |
732 | input_inject_event(handle, EV_KEY, alt_code, 1); | |
733 | input_inject_event(handle, EV_KEY, KEY_SYSRQ, 1); | |
734 | input_inject_event(handle, EV_SYN, SYN_REPORT, 1); | |
735 | ||
736 | input_inject_event(handle, EV_KEY, KEY_SYSRQ, 0); | |
737 | input_inject_event(handle, EV_KEY, alt_code, 0); | |
738 | input_inject_event(handle, EV_SYN, SYN_REPORT, 1); | |
7ab7b5ad DT |
739 | |
740 | mb(); | |
741 | sysrq->reinjecting = false; | |
fcb71930 DT |
742 | } |
743 | } | |
97f5f0cd | 744 | |
154b7a48 MP |
745 | static bool sysrq_handle_keypress(struct sysrq_state *sysrq, |
746 | unsigned int code, int value) | |
97f5f0cd | 747 | { |
fcb71930 | 748 | bool was_active = sysrq->active; |
1966cb22 DT |
749 | bool suppress; |
750 | ||
154b7a48 | 751 | switch (code) { |
7ab7b5ad | 752 | |
154b7a48 MP |
753 | case KEY_LEFTALT: |
754 | case KEY_RIGHTALT: | |
755 | if (!value) { | |
756 | /* One of ALTs is being released */ | |
757 | if (sysrq->active && code == sysrq->alt_use) | |
758 | sysrq->active = false; | |
1966cb22 | 759 | |
154b7a48 MP |
760 | sysrq->alt = KEY_RESERVED; |
761 | ||
762 | } else if (value != 2) { | |
763 | sysrq->alt = code; | |
764 | sysrq->need_reinject = false; | |
765 | } | |
fcb71930 | 766 | break; |
97f5f0cd | 767 | |
154b7a48 MP |
768 | case KEY_SYSRQ: |
769 | if (value == 1 && sysrq->alt != KEY_RESERVED) { | |
770 | sysrq->active = true; | |
771 | sysrq->alt_use = sysrq->alt; | |
772 | /* | |
773 | * If nothing else will be pressed we'll need | |
774 | * to re-inject Alt-SysRq keysroke. | |
775 | */ | |
776 | sysrq->need_reinject = true; | |
777 | } | |
97f5f0cd | 778 | |
154b7a48 MP |
779 | /* |
780 | * Pretend that sysrq was never pressed at all. This | |
781 | * is needed to properly handle KGDB which will try | |
782 | * to release all keys after exiting debugger. If we | |
783 | * do not clear key bit it KGDB will end up sending | |
784 | * release events for Alt and SysRq, potentially | |
785 | * triggering print screen function. | |
786 | */ | |
787 | if (sysrq->active) | |
788 | clear_bit(KEY_SYSRQ, sysrq->handle.dev->key); | |
f5dec511 | 789 | |
154b7a48 | 790 | break; |
fcb71930 | 791 | |
154b7a48 MP |
792 | default: |
793 | if (sysrq->active && value && value != 2) { | |
794 | sysrq->need_reinject = false; | |
795 | __handle_sysrq(sysrq_xlate[code], true); | |
796 | } | |
797 | break; | |
798 | } | |
fcb71930 | 799 | |
154b7a48 | 800 | suppress = sysrq->active; |
fcb71930 | 801 | |
154b7a48 | 802 | if (!sysrq->active) { |
fcb71930 | 803 | |
154b7a48 MP |
804 | /* |
805 | * See if reset sequence has changed since the last time. | |
806 | */ | |
807 | if (sysrq->reset_seq_version != sysrq_reset_seq_version) | |
808 | sysrq_parse_reset_sequence(sysrq); | |
fcb71930 | 809 | |
154b7a48 MP |
810 | /* |
811 | * If we are not suppressing key presses keep track of | |
812 | * keyboard state so we can release keys that have been | |
813 | * pressed before entering SysRq mode. | |
814 | */ | |
815 | if (value) | |
816 | set_bit(code, sysrq->key_down); | |
817 | else | |
818 | clear_bit(code, sysrq->key_down); | |
819 | ||
820 | if (was_active) | |
821 | schedule_work(&sysrq->reinject_work); | |
822 | ||
39030786 MP |
823 | /* Check for reset sequence */ |
824 | sysrq_detect_reset_sequence(sysrq, code, value); | |
97f5f0cd | 825 | |
154b7a48 MP |
826 | } else if (value == 0 && test_and_clear_bit(code, sysrq->key_down)) { |
827 | /* | |
828 | * Pass on release events for keys that was pressed before | |
829 | * entering SysRq mode. | |
830 | */ | |
831 | suppress = false; | |
832 | } | |
fcb71930 | 833 | |
154b7a48 MP |
834 | return suppress; |
835 | } | |
fcb71930 | 836 | |
154b7a48 MP |
837 | static bool sysrq_filter(struct input_handle *handle, |
838 | unsigned int type, unsigned int code, int value) | |
839 | { | |
840 | struct sysrq_state *sysrq = handle->private; | |
841 | bool suppress; | |
fcb71930 | 842 | |
154b7a48 MP |
843 | /* |
844 | * Do not filter anything if we are in the process of re-injecting | |
845 | * Alt+SysRq combination. | |
846 | */ | |
847 | if (sysrq->reinjecting) | |
848 | return false; | |
849 | ||
850 | switch (type) { | |
851 | ||
852 | case EV_SYN: | |
853 | suppress = false; | |
854 | break; | |
855 | ||
856 | case EV_KEY: | |
857 | suppress = sysrq_handle_keypress(sysrq, code, value); | |
97f5f0cd DT |
858 | break; |
859 | ||
860 | default: | |
fcb71930 | 861 | suppress = sysrq->active; |
97f5f0cd DT |
862 | break; |
863 | } | |
864 | ||
1966cb22 | 865 | return suppress; |
97f5f0cd DT |
866 | } |
867 | ||
868 | static int sysrq_connect(struct input_handler *handler, | |
869 | struct input_dev *dev, | |
870 | const struct input_device_id *id) | |
871 | { | |
fcb71930 | 872 | struct sysrq_state *sysrq; |
97f5f0cd DT |
873 | int error; |
874 | ||
fcb71930 DT |
875 | sysrq = kzalloc(sizeof(struct sysrq_state), GFP_KERNEL); |
876 | if (!sysrq) | |
97f5f0cd DT |
877 | return -ENOMEM; |
878 | ||
fcb71930 DT |
879 | INIT_WORK(&sysrq->reinject_work, sysrq_reinject_alt_sysrq); |
880 | ||
881 | sysrq->handle.dev = dev; | |
882 | sysrq->handle.handler = handler; | |
883 | sysrq->handle.name = "sysrq"; | |
884 | sysrq->handle.private = sysrq; | |
3d289517 MP |
885 | setup_timer(&sysrq->keyreset_timer, |
886 | sysrq_do_reset, (unsigned long)sysrq); | |
97f5f0cd | 887 | |
fcb71930 | 888 | error = input_register_handle(&sysrq->handle); |
97f5f0cd DT |
889 | if (error) { |
890 | pr_err("Failed to register input sysrq handler, error %d\n", | |
891 | error); | |
892 | goto err_free; | |
893 | } | |
894 | ||
fcb71930 | 895 | error = input_open_device(&sysrq->handle); |
97f5f0cd DT |
896 | if (error) { |
897 | pr_err("Failed to open input device, error %d\n", error); | |
898 | goto err_unregister; | |
899 | } | |
900 | ||
901 | return 0; | |
902 | ||
903 | err_unregister: | |
fcb71930 | 904 | input_unregister_handle(&sysrq->handle); |
97f5f0cd | 905 | err_free: |
fcb71930 | 906 | kfree(sysrq); |
97f5f0cd DT |
907 | return error; |
908 | } | |
909 | ||
910 | static void sysrq_disconnect(struct input_handle *handle) | |
911 | { | |
fcb71930 DT |
912 | struct sysrq_state *sysrq = handle->private; |
913 | ||
97f5f0cd | 914 | input_close_device(handle); |
fcb71930 | 915 | cancel_work_sync(&sysrq->reinject_work); |
39030786 | 916 | del_timer_sync(&sysrq->keyreset_timer); |
97f5f0cd | 917 | input_unregister_handle(handle); |
fcb71930 | 918 | kfree(sysrq); |
97f5f0cd DT |
919 | } |
920 | ||
921 | /* | |
1966cb22 DT |
922 | * We are matching on KEY_LEFTALT instead of KEY_SYSRQ because not all |
923 | * keyboards have SysRq key predefined and so user may add it to keymap | |
97f5f0cd DT |
924 | * later, but we expect all such keyboards to have left alt. |
925 | */ | |
926 | static const struct input_device_id sysrq_ids[] = { | |
927 | { | |
928 | .flags = INPUT_DEVICE_ID_MATCH_EVBIT | | |
929 | INPUT_DEVICE_ID_MATCH_KEYBIT, | |
930 | .evbit = { BIT_MASK(EV_KEY) }, | |
931 | .keybit = { BIT_MASK(KEY_LEFTALT) }, | |
932 | }, | |
933 | { }, | |
934 | }; | |
935 | ||
936 | static struct input_handler sysrq_handler = { | |
937 | .filter = sysrq_filter, | |
938 | .connect = sysrq_connect, | |
939 | .disconnect = sysrq_disconnect, | |
940 | .name = "sysrq", | |
941 | .id_table = sysrq_ids, | |
942 | }; | |
943 | ||
944 | static bool sysrq_handler_registered; | |
945 | ||
946 | static inline void sysrq_register_handler(void) | |
947 | { | |
154b7a48 | 948 | unsigned short key; |
97f5f0cd | 949 | int error; |
154b7a48 MP |
950 | int i; |
951 | ||
4c076eb0 | 952 | /* First check if a __weak interface was instantiated. */ |
adf96e6f LT |
953 | for (i = 0; i < ARRAY_SIZE(sysrq_reset_seq); i++) { |
954 | key = platform_sysrq_reset_seq[i]; | |
955 | if (key == KEY_RESERVED || key > KEY_MAX) | |
956 | break; | |
154b7a48 | 957 | |
adf96e6f | 958 | sysrq_reset_seq[sysrq_reset_seq_len++] = key; |
154b7a48 | 959 | } |
97f5f0cd | 960 | |
4c076eb0 MP |
961 | /* |
962 | * DT configuration takes precedence over anything that would | |
963 | * have been defined via the __weak interface. | |
964 | */ | |
965 | sysrq_of_get_keyreset_config(); | |
966 | ||
97f5f0cd DT |
967 | error = input_register_handler(&sysrq_handler); |
968 | if (error) | |
969 | pr_err("Failed to register input handler, error %d", error); | |
970 | else | |
971 | sysrq_handler_registered = true; | |
972 | } | |
973 | ||
974 | static inline void sysrq_unregister_handler(void) | |
975 | { | |
976 | if (sysrq_handler_registered) { | |
977 | input_unregister_handler(&sysrq_handler); | |
978 | sysrq_handler_registered = false; | |
979 | } | |
980 | } | |
981 | ||
154b7a48 MP |
982 | static int sysrq_reset_seq_param_set(const char *buffer, |
983 | const struct kernel_param *kp) | |
984 | { | |
985 | unsigned long val; | |
986 | int error; | |
987 | ||
86b40567 | 988 | error = kstrtoul(buffer, 0, &val); |
154b7a48 MP |
989 | if (error < 0) |
990 | return error; | |
991 | ||
992 | if (val > KEY_MAX) | |
993 | return -EINVAL; | |
994 | ||
995 | *((unsigned short *)kp->arg) = val; | |
996 | sysrq_reset_seq_version++; | |
997 | ||
998 | return 0; | |
999 | } | |
1000 | ||
1001 | static struct kernel_param_ops param_ops_sysrq_reset_seq = { | |
1002 | .get = param_get_ushort, | |
1003 | .set = sysrq_reset_seq_param_set, | |
1004 | }; | |
1005 | ||
1006 | #define param_check_sysrq_reset_seq(name, p) \ | |
1007 | __param_check(name, p, unsigned short) | |
1008 | ||
1009 | module_param_array_named(reset_seq, sysrq_reset_seq, sysrq_reset_seq, | |
1010 | &sysrq_reset_seq_len, 0644); | |
1011 | ||
39030786 MP |
1012 | module_param_named(sysrq_downtime_ms, sysrq_reset_downtime_ms, int, 0644); |
1013 | ||
97f5f0cd DT |
1014 | #else |
1015 | ||
1016 | static inline void sysrq_register_handler(void) | |
1017 | { | |
1018 | } | |
1019 | ||
1020 | static inline void sysrq_unregister_handler(void) | |
1021 | { | |
1022 | } | |
1023 | ||
1024 | #endif /* CONFIG_INPUT */ | |
1025 | ||
1026 | int sysrq_toggle_support(int enable_mask) | |
1027 | { | |
1028 | bool was_enabled = sysrq_on(); | |
1029 | ||
1030 | sysrq_enabled = enable_mask; | |
1031 | ||
1032 | if (was_enabled != sysrq_on()) { | |
1033 | if (sysrq_on()) | |
1034 | sysrq_register_handler(); | |
1035 | else | |
1036 | sysrq_unregister_handler(); | |
1037 | } | |
1038 | ||
1039 | return 0; | |
1040 | } | |
1041 | ||
cf62ddce | 1042 | static int __sysrq_swap_key_ops(int key, struct sysrq_key_op *insert_op_p, |
bf36b901 AM |
1043 | struct sysrq_key_op *remove_op_p) |
1044 | { | |
1da177e4 LT |
1045 | int retval; |
1046 | unsigned long flags; | |
1047 | ||
1048 | spin_lock_irqsave(&sysrq_key_table_lock, flags); | |
1049 | if (__sysrq_get_key_op(key) == remove_op_p) { | |
1050 | __sysrq_put_key_op(key, insert_op_p); | |
1051 | retval = 0; | |
1052 | } else { | |
1053 | retval = -1; | |
1054 | } | |
1055 | spin_unlock_irqrestore(&sysrq_key_table_lock, flags); | |
1da177e4 LT |
1056 | return retval; |
1057 | } | |
1058 | ||
1059 | int register_sysrq_key(int key, struct sysrq_key_op *op_p) | |
1060 | { | |
1061 | return __sysrq_swap_key_ops(key, op_p, NULL); | |
1062 | } | |
bf36b901 | 1063 | EXPORT_SYMBOL(register_sysrq_key); |
1da177e4 LT |
1064 | |
1065 | int unregister_sysrq_key(int key, struct sysrq_key_op *op_p) | |
1066 | { | |
1067 | return __sysrq_swap_key_ops(key, NULL, op_p); | |
1068 | } | |
1da177e4 | 1069 | EXPORT_SYMBOL(unregister_sysrq_key); |
f40cbaa5 AD |
1070 | |
1071 | #ifdef CONFIG_PROC_FS | |
1072 | /* | |
1073 | * writing 'C' to /proc/sysrq-trigger is like sysrq-C | |
1074 | */ | |
1075 | static ssize_t write_sysrq_trigger(struct file *file, const char __user *buf, | |
1076 | size_t count, loff_t *ppos) | |
1077 | { | |
1078 | if (count) { | |
1079 | char c; | |
1080 | ||
1081 | if (get_user(c, buf)) | |
1082 | return -EFAULT; | |
f335397d | 1083 | __handle_sysrq(c, false); |
f40cbaa5 | 1084 | } |
97f5f0cd | 1085 | |
f40cbaa5 AD |
1086 | return count; |
1087 | } | |
1088 | ||
1089 | static const struct file_operations proc_sysrq_trigger_operations = { | |
1090 | .write = write_sysrq_trigger, | |
6038f373 | 1091 | .llseek = noop_llseek, |
f40cbaa5 AD |
1092 | }; |
1093 | ||
97f5f0cd DT |
1094 | static void sysrq_init_procfs(void) |
1095 | { | |
1096 | if (!proc_create("sysrq-trigger", S_IWUSR, NULL, | |
1097 | &proc_sysrq_trigger_operations)) | |
1098 | pr_err("Failed to register proc interface\n"); | |
1099 | } | |
1100 | ||
1101 | #else | |
1102 | ||
1103 | static inline void sysrq_init_procfs(void) | |
1104 | { | |
1105 | } | |
1106 | ||
1107 | #endif /* CONFIG_PROC_FS */ | |
1108 | ||
f40cbaa5 AD |
1109 | static int __init sysrq_init(void) |
1110 | { | |
97f5f0cd DT |
1111 | sysrq_init_procfs(); |
1112 | ||
1113 | if (sysrq_on()) | |
1114 | sysrq_register_handler(); | |
1115 | ||
f40cbaa5 AD |
1116 | return 0; |
1117 | } | |
1118 | module_init(sysrq_init); |