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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> |
722773af | 49 | #include <linux/rcupdate.h> |
1da177e4 LT |
50 | |
51 | #include <asm/ptrace.h> | |
2033b0c3 | 52 | #include <asm/irq_regs.h> |
1da177e4 LT |
53 | |
54 | /* Whether we react on sysrq keys or just ignore them */ | |
8eaede49 | 55 | static int __read_mostly sysrq_enabled = CONFIG_MAGIC_SYSRQ_DEFAULT_ENABLE; |
97f5f0cd | 56 | static bool __read_mostly sysrq_always_enabled; |
5d6f647f | 57 | |
97f5f0cd | 58 | static bool sysrq_on(void) |
5d6f647f | 59 | { |
97f5f0cd | 60 | return sysrq_enabled || sysrq_always_enabled; |
5d6f647f IM |
61 | } |
62 | ||
63 | /* | |
64 | * A value of 1 means 'all', other nonzero values are an op mask: | |
65 | */ | |
97f5f0cd | 66 | static bool sysrq_on_mask(int mask) |
5d6f647f | 67 | { |
97f5f0cd DT |
68 | return sysrq_always_enabled || |
69 | sysrq_enabled == 1 || | |
70 | (sysrq_enabled & mask); | |
5d6f647f IM |
71 | } |
72 | ||
73 | static int __init sysrq_always_enabled_setup(char *str) | |
74 | { | |
97f5f0cd DT |
75 | sysrq_always_enabled = true; |
76 | pr_info("sysrq always enabled.\n"); | |
5d6f647f IM |
77 | |
78 | return 1; | |
79 | } | |
80 | ||
81 | __setup("sysrq_always_enabled", sysrq_always_enabled_setup); | |
82 | ||
1da177e4 | 83 | |
1495cc9d | 84 | static void sysrq_handle_loglevel(int key) |
1da177e4 LT |
85 | { |
86 | int i; | |
97f5f0cd | 87 | |
1da177e4 | 88 | i = key - '0'; |
a8fe19eb | 89 | console_loglevel = CONSOLE_LOGLEVEL_DEFAULT; |
401e4a7c | 90 | pr_info("Loglevel set to %d\n", i); |
1da177e4 | 91 | console_loglevel = i; |
bf36b901 | 92 | } |
1da177e4 LT |
93 | static struct sysrq_key_op sysrq_loglevel_op = { |
94 | .handler = sysrq_handle_loglevel, | |
208b95ce | 95 | .help_msg = "loglevel(0-9)", |
1da177e4 LT |
96 | .action_msg = "Changing Loglevel", |
97 | .enable_mask = SYSRQ_ENABLE_LOG, | |
98 | }; | |
99 | ||
1da177e4 | 100 | #ifdef CONFIG_VT |
1495cc9d | 101 | static void sysrq_handle_SAK(int key) |
1da177e4 | 102 | { |
8b6312f4 | 103 | struct work_struct *SAK_work = &vc_cons[fg_console].SAK_work; |
8b6312f4 | 104 | schedule_work(SAK_work); |
1da177e4 LT |
105 | } |
106 | static struct sysrq_key_op sysrq_SAK_op = { | |
107 | .handler = sysrq_handle_SAK, | |
afa80ccb | 108 | .help_msg = "sak(k)", |
1da177e4 LT |
109 | .action_msg = "SAK", |
110 | .enable_mask = SYSRQ_ENABLE_KEYBOARD, | |
111 | }; | |
bf36b901 | 112 | #else |
97f5f0cd | 113 | #define sysrq_SAK_op (*(struct sysrq_key_op *)NULL) |
1da177e4 LT |
114 | #endif |
115 | ||
116 | #ifdef CONFIG_VT | |
1495cc9d | 117 | static void sysrq_handle_unraw(int key) |
1da177e4 | 118 | { |
079c9534 | 119 | vt_reset_unicode(fg_console); |
1da177e4 | 120 | } |
079c9534 | 121 | |
1da177e4 LT |
122 | static struct sysrq_key_op sysrq_unraw_op = { |
123 | .handler = sysrq_handle_unraw, | |
afa80ccb | 124 | .help_msg = "unraw(r)", |
2e8ecb9d | 125 | .action_msg = "Keyboard mode set to system default", |
1da177e4 LT |
126 | .enable_mask = SYSRQ_ENABLE_KEYBOARD, |
127 | }; | |
bf36b901 | 128 | #else |
97f5f0cd | 129 | #define sysrq_unraw_op (*(struct sysrq_key_op *)NULL) |
1da177e4 LT |
130 | #endif /* CONFIG_VT */ |
131 | ||
1495cc9d | 132 | static void sysrq_handle_crash(int key) |
86b1ae38 | 133 | { |
d6580a9f | 134 | char *killer = NULL; |
cab8bd34 | 135 | |
984cf355 AS |
136 | /* we need to release the RCU read lock here, |
137 | * otherwise we get an annoying | |
138 | * 'BUG: sleeping function called from invalid context' | |
139 | * complaint from the kernel before the panic. | |
140 | */ | |
141 | rcu_read_unlock(); | |
cab8bd34 HS |
142 | panic_on_oops = 1; /* force panic */ |
143 | wmb(); | |
d6580a9f | 144 | *killer = 1; |
86b1ae38 | 145 | } |
cab8bd34 | 146 | static struct sysrq_key_op sysrq_crash_op = { |
d6580a9f | 147 | .handler = sysrq_handle_crash, |
afa80ccb | 148 | .help_msg = "crash(c)", |
d6580a9f | 149 | .action_msg = "Trigger a crash", |
86b1ae38 HN |
150 | .enable_mask = SYSRQ_ENABLE_DUMP, |
151 | }; | |
86b1ae38 | 152 | |
1495cc9d | 153 | static void sysrq_handle_reboot(int key) |
1da177e4 | 154 | { |
b2e9c7d0 | 155 | lockdep_off(); |
1da177e4 | 156 | local_irq_enable(); |
4de8b9b7 | 157 | emergency_restart(); |
1da177e4 | 158 | } |
1da177e4 LT |
159 | static struct sysrq_key_op sysrq_reboot_op = { |
160 | .handler = sysrq_handle_reboot, | |
afa80ccb | 161 | .help_msg = "reboot(b)", |
1da177e4 LT |
162 | .action_msg = "Resetting", |
163 | .enable_mask = SYSRQ_ENABLE_BOOT, | |
164 | }; | |
165 | ||
1495cc9d | 166 | static void sysrq_handle_sync(int key) |
1da177e4 LT |
167 | { |
168 | emergency_sync(); | |
169 | } | |
1da177e4 LT |
170 | static struct sysrq_key_op sysrq_sync_op = { |
171 | .handler = sysrq_handle_sync, | |
afa80ccb | 172 | .help_msg = "sync(s)", |
1da177e4 LT |
173 | .action_msg = "Emergency Sync", |
174 | .enable_mask = SYSRQ_ENABLE_SYNC, | |
175 | }; | |
176 | ||
1495cc9d | 177 | static void sysrq_handle_show_timers(int key) |
88ad0bf6 IM |
178 | { |
179 | sysrq_timer_list_show(); | |
180 | } | |
181 | ||
182 | static struct sysrq_key_op sysrq_show_timers_op = { | |
183 | .handler = sysrq_handle_show_timers, | |
afa80ccb | 184 | .help_msg = "show-all-timers(q)", |
322acf65 | 185 | .action_msg = "Show clockevent devices & pending hrtimers (no others)", |
88ad0bf6 IM |
186 | }; |
187 | ||
1495cc9d | 188 | static void sysrq_handle_mountro(int key) |
1da177e4 LT |
189 | { |
190 | emergency_remount(); | |
191 | } | |
1da177e4 LT |
192 | static struct sysrq_key_op sysrq_mountro_op = { |
193 | .handler = sysrq_handle_mountro, | |
afa80ccb | 194 | .help_msg = "unmount(u)", |
1da177e4 LT |
195 | .action_msg = "Emergency Remount R/O", |
196 | .enable_mask = SYSRQ_ENABLE_REMOUNT, | |
197 | }; | |
198 | ||
8c64580d | 199 | #ifdef CONFIG_LOCKDEP |
1495cc9d | 200 | static void sysrq_handle_showlocks(int key) |
de5097c2 | 201 | { |
9a11b49a | 202 | debug_show_all_locks(); |
de5097c2 | 203 | } |
8c64580d | 204 | |
de5097c2 IM |
205 | static struct sysrq_key_op sysrq_showlocks_op = { |
206 | .handler = sysrq_handle_showlocks, | |
afa80ccb | 207 | .help_msg = "show-all-locks(d)", |
de5097c2 IM |
208 | .action_msg = "Show Locks Held", |
209 | }; | |
bf36b901 | 210 | #else |
97f5f0cd | 211 | #define sysrq_showlocks_op (*(struct sysrq_key_op *)NULL) |
de5097c2 | 212 | #endif |
1da177e4 | 213 | |
5045bcae RR |
214 | #ifdef CONFIG_SMP |
215 | static DEFINE_SPINLOCK(show_lock); | |
216 | ||
217 | static void showacpu(void *dummy) | |
218 | { | |
219 | unsigned long flags; | |
220 | ||
221 | /* Idle CPUs have no interesting backtrace. */ | |
222 | if (idle_cpu(smp_processor_id())) | |
223 | return; | |
224 | ||
225 | spin_lock_irqsave(&show_lock, flags); | |
401e4a7c | 226 | pr_info("CPU%d:\n", smp_processor_id()); |
5045bcae RR |
227 | show_stack(NULL, NULL); |
228 | spin_unlock_irqrestore(&show_lock, flags); | |
229 | } | |
230 | ||
231 | static void sysrq_showregs_othercpus(struct work_struct *dummy) | |
232 | { | |
8b604d52 | 233 | smp_call_function(showacpu, NULL, 0); |
5045bcae RR |
234 | } |
235 | ||
236 | static DECLARE_WORK(sysrq_showallcpus, sysrq_showregs_othercpus); | |
237 | ||
1495cc9d | 238 | static void sysrq_handle_showallcpus(int key) |
5045bcae | 239 | { |
47cab6a7 IM |
240 | /* |
241 | * Fall back to the workqueue based printing if the | |
242 | * backtrace printing did not succeed or the | |
243 | * architecture has no support for it: | |
244 | */ | |
245 | if (!trigger_all_cpu_backtrace()) { | |
246 | struct pt_regs *regs = get_irq_regs(); | |
247 | ||
248 | if (regs) { | |
401e4a7c | 249 | pr_info("CPU%d:\n", smp_processor_id()); |
47cab6a7 IM |
250 | show_regs(regs); |
251 | } | |
252 | schedule_work(&sysrq_showallcpus); | |
253 | } | |
5045bcae RR |
254 | } |
255 | ||
256 | static struct sysrq_key_op sysrq_showallcpus_op = { | |
257 | .handler = sysrq_handle_showallcpus, | |
afa80ccb | 258 | .help_msg = "show-backtrace-all-active-cpus(l)", |
5045bcae RR |
259 | .action_msg = "Show backtrace of all active CPUs", |
260 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
261 | }; | |
262 | #endif | |
263 | ||
1495cc9d | 264 | static void sysrq_handle_showregs(int key) |
1da177e4 | 265 | { |
7d12e780 DH |
266 | struct pt_regs *regs = get_irq_regs(); |
267 | if (regs) | |
268 | show_regs(regs); | |
cdd6c482 | 269 | perf_event_print_debug(); |
1da177e4 LT |
270 | } |
271 | static struct sysrq_key_op sysrq_showregs_op = { | |
272 | .handler = sysrq_handle_showregs, | |
afa80ccb | 273 | .help_msg = "show-registers(p)", |
1da177e4 LT |
274 | .action_msg = "Show Regs", |
275 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
276 | }; | |
277 | ||
1495cc9d | 278 | static void sysrq_handle_showstate(int key) |
1da177e4 LT |
279 | { |
280 | show_state(); | |
3494fc30 | 281 | show_workqueue_state(); |
1da177e4 LT |
282 | } |
283 | static struct sysrq_key_op sysrq_showstate_op = { | |
284 | .handler = sysrq_handle_showstate, | |
afa80ccb | 285 | .help_msg = "show-task-states(t)", |
1da177e4 LT |
286 | .action_msg = "Show State", |
287 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
288 | }; | |
289 | ||
1495cc9d | 290 | static void sysrq_handle_showstate_blocked(int key) |
e59e2ae2 IM |
291 | { |
292 | show_state_filter(TASK_UNINTERRUPTIBLE); | |
293 | } | |
294 | static struct sysrq_key_op sysrq_showstate_blocked_op = { | |
295 | .handler = sysrq_handle_showstate_blocked, | |
afa80ccb | 296 | .help_msg = "show-blocked-tasks(w)", |
e59e2ae2 IM |
297 | .action_msg = "Show Blocked State", |
298 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
299 | }; | |
300 | ||
69f698ad PZ |
301 | #ifdef CONFIG_TRACING |
302 | #include <linux/ftrace.h> | |
303 | ||
1495cc9d | 304 | static void sysrq_ftrace_dump(int key) |
69f698ad | 305 | { |
cecbca96 | 306 | ftrace_dump(DUMP_ALL); |
69f698ad PZ |
307 | } |
308 | static struct sysrq_key_op sysrq_ftrace_dump_op = { | |
309 | .handler = sysrq_ftrace_dump, | |
afa80ccb | 310 | .help_msg = "dump-ftrace-buffer(z)", |
69f698ad PZ |
311 | .action_msg = "Dump ftrace buffer", |
312 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
313 | }; | |
314 | #else | |
97f5f0cd | 315 | #define sysrq_ftrace_dump_op (*(struct sysrq_key_op *)NULL) |
69f698ad | 316 | #endif |
e59e2ae2 | 317 | |
1495cc9d | 318 | static void sysrq_handle_showmem(int key) |
1da177e4 | 319 | { |
b2b755b5 | 320 | show_mem(0); |
1da177e4 LT |
321 | } |
322 | static struct sysrq_key_op sysrq_showmem_op = { | |
323 | .handler = sysrq_handle_showmem, | |
afa80ccb | 324 | .help_msg = "show-memory-usage(m)", |
1da177e4 LT |
325 | .action_msg = "Show Memory", |
326 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
327 | }; | |
328 | ||
bf36b901 AM |
329 | /* |
330 | * Signal sysrq helper function. Sends a signal to all user processes. | |
331 | */ | |
1da177e4 LT |
332 | static void send_sig_all(int sig) |
333 | { | |
334 | struct task_struct *p; | |
335 | ||
e502babe | 336 | read_lock(&tasklist_lock); |
1da177e4 | 337 | for_each_process(p) { |
d3a532a9 AV |
338 | if (p->flags & PF_KTHREAD) |
339 | continue; | |
340 | if (is_global_init(p)) | |
341 | continue; | |
342 | ||
b82c3287 | 343 | do_send_sig_info(sig, SEND_SIG_FORCED, p, true); |
1da177e4 | 344 | } |
e502babe | 345 | read_unlock(&tasklist_lock); |
1da177e4 LT |
346 | } |
347 | ||
1495cc9d | 348 | static void sysrq_handle_term(int key) |
1da177e4 LT |
349 | { |
350 | send_sig_all(SIGTERM); | |
a8fe19eb | 351 | console_loglevel = CONSOLE_LOGLEVEL_DEBUG; |
1da177e4 LT |
352 | } |
353 | static struct sysrq_key_op sysrq_term_op = { | |
354 | .handler = sysrq_handle_term, | |
afa80ccb | 355 | .help_msg = "terminate-all-tasks(e)", |
1da177e4 LT |
356 | .action_msg = "Terminate All Tasks", |
357 | .enable_mask = SYSRQ_ENABLE_SIGNAL, | |
358 | }; | |
359 | ||
65f27f38 | 360 | static void moom_callback(struct work_struct *ignored) |
1da177e4 | 361 | { |
6e0fc46d DR |
362 | const gfp_t gfp_mask = GFP_KERNEL; |
363 | struct oom_control oc = { | |
364 | .zonelist = node_zonelist(first_memory_node, gfp_mask), | |
365 | .nodemask = NULL, | |
2a966b77 | 366 | .memcg = NULL, |
6e0fc46d | 367 | .gfp_mask = gfp_mask, |
54e9e291 | 368 | .order = -1, |
6e0fc46d DR |
369 | }; |
370 | ||
dc56401f | 371 | mutex_lock(&oom_lock); |
6e0fc46d | 372 | if (!out_of_memory(&oc)) |
c32b3cbe | 373 | pr_info("OOM request ignored because killer is disabled\n"); |
dc56401f | 374 | mutex_unlock(&oom_lock); |
1da177e4 LT |
375 | } |
376 | ||
65f27f38 | 377 | static DECLARE_WORK(moom_work, moom_callback); |
1da177e4 | 378 | |
1495cc9d | 379 | static void sysrq_handle_moom(int key) |
1da177e4 LT |
380 | { |
381 | schedule_work(&moom_work); | |
382 | } | |
383 | static struct sysrq_key_op sysrq_moom_op = { | |
384 | .handler = sysrq_handle_moom, | |
afa80ccb | 385 | .help_msg = "memory-full-oom-kill(f)", |
1da177e4 | 386 | .action_msg = "Manual OOM execution", |
b4236f81 | 387 | .enable_mask = SYSRQ_ENABLE_SIGNAL, |
1da177e4 LT |
388 | }; |
389 | ||
c2d75438 | 390 | #ifdef CONFIG_BLOCK |
1495cc9d | 391 | static void sysrq_handle_thaw(int key) |
c2d75438 ES |
392 | { |
393 | emergency_thaw_all(); | |
394 | } | |
395 | static struct sysrq_key_op sysrq_thaw_op = { | |
396 | .handler = sysrq_handle_thaw, | |
afa80ccb | 397 | .help_msg = "thaw-filesystems(j)", |
c2d75438 ES |
398 | .action_msg = "Emergency Thaw of all frozen filesystems", |
399 | .enable_mask = SYSRQ_ENABLE_SIGNAL, | |
400 | }; | |
401 | #endif | |
402 | ||
1495cc9d | 403 | static void sysrq_handle_kill(int key) |
1da177e4 LT |
404 | { |
405 | send_sig_all(SIGKILL); | |
a8fe19eb | 406 | console_loglevel = CONSOLE_LOGLEVEL_DEBUG; |
1da177e4 LT |
407 | } |
408 | static struct sysrq_key_op sysrq_kill_op = { | |
409 | .handler = sysrq_handle_kill, | |
afa80ccb | 410 | .help_msg = "kill-all-tasks(i)", |
1da177e4 LT |
411 | .action_msg = "Kill All Tasks", |
412 | .enable_mask = SYSRQ_ENABLE_SIGNAL, | |
413 | }; | |
414 | ||
1495cc9d | 415 | static void sysrq_handle_unrt(int key) |
1da177e4 LT |
416 | { |
417 | normalize_rt_tasks(); | |
418 | } | |
419 | static struct sysrq_key_op sysrq_unrt_op = { | |
420 | .handler = sysrq_handle_unrt, | |
afa80ccb | 421 | .help_msg = "nice-all-RT-tasks(n)", |
1da177e4 LT |
422 | .action_msg = "Nice All RT Tasks", |
423 | .enable_mask = SYSRQ_ENABLE_RTNICE, | |
424 | }; | |
425 | ||
426 | /* Key Operations table and lock */ | |
427 | static DEFINE_SPINLOCK(sysrq_key_table_lock); | |
bf36b901 AM |
428 | |
429 | static struct sysrq_key_op *sysrq_key_table[36] = { | |
430 | &sysrq_loglevel_op, /* 0 */ | |
431 | &sysrq_loglevel_op, /* 1 */ | |
432 | &sysrq_loglevel_op, /* 2 */ | |
433 | &sysrq_loglevel_op, /* 3 */ | |
434 | &sysrq_loglevel_op, /* 4 */ | |
435 | &sysrq_loglevel_op, /* 5 */ | |
436 | &sysrq_loglevel_op, /* 6 */ | |
437 | &sysrq_loglevel_op, /* 7 */ | |
438 | &sysrq_loglevel_op, /* 8 */ | |
439 | &sysrq_loglevel_op, /* 9 */ | |
440 | ||
441 | /* | |
d346cce3 RD |
442 | * a: Don't use for system provided sysrqs, it is handled specially on |
443 | * sparc and will never arrive. | |
bf36b901 AM |
444 | */ |
445 | NULL, /* a */ | |
446 | &sysrq_reboot_op, /* b */ | |
cab8bd34 | 447 | &sysrq_crash_op, /* c & ibm_emac driver debug */ |
bf36b901 AM |
448 | &sysrq_showlocks_op, /* d */ |
449 | &sysrq_term_op, /* e */ | |
450 | &sysrq_moom_op, /* f */ | |
364b5b7b | 451 | /* g: May be registered for the kernel debugger */ |
bf36b901 | 452 | NULL, /* g */ |
c2d75438 | 453 | NULL, /* h - reserved for help */ |
bf36b901 | 454 | &sysrq_kill_op, /* i */ |
c2d75438 ES |
455 | #ifdef CONFIG_BLOCK |
456 | &sysrq_thaw_op, /* j */ | |
457 | #else | |
bf36b901 | 458 | NULL, /* j */ |
c2d75438 | 459 | #endif |
bf36b901 | 460 | &sysrq_SAK_op, /* k */ |
5045bcae RR |
461 | #ifdef CONFIG_SMP |
462 | &sysrq_showallcpus_op, /* l */ | |
463 | #else | |
bf36b901 | 464 | NULL, /* l */ |
5045bcae | 465 | #endif |
bf36b901 AM |
466 | &sysrq_showmem_op, /* m */ |
467 | &sysrq_unrt_op, /* n */ | |
d346cce3 | 468 | /* o: This will often be registered as 'Off' at init time */ |
bf36b901 AM |
469 | NULL, /* o */ |
470 | &sysrq_showregs_op, /* p */ | |
88ad0bf6 | 471 | &sysrq_show_timers_op, /* q */ |
d346cce3 | 472 | &sysrq_unraw_op, /* r */ |
bf36b901 AM |
473 | &sysrq_sync_op, /* s */ |
474 | &sysrq_showstate_op, /* t */ | |
475 | &sysrq_mountro_op, /* u */ | |
364b5b7b | 476 | /* v: May be registered for frame buffer console restore */ |
bf36b901 | 477 | NULL, /* v */ |
d346cce3 | 478 | &sysrq_showstate_blocked_op, /* w */ |
d1e9a4f5 | 479 | /* x: May be registered on mips for TLB dump */ |
d346cce3 | 480 | /* x: May be registered on ppc/powerpc for xmon */ |
916ca14a | 481 | /* x: May be registered on sparc64 for global PMU dump */ |
d346cce3 | 482 | NULL, /* x */ |
93dae5b7 | 483 | /* y: May be registered on sparc64 for global register dump */ |
bf36b901 | 484 | NULL, /* y */ |
69f698ad | 485 | &sysrq_ftrace_dump_op, /* z */ |
1da177e4 LT |
486 | }; |
487 | ||
488 | /* key2index calculation, -1 on invalid index */ | |
bf36b901 AM |
489 | static int sysrq_key_table_key2index(int key) |
490 | { | |
1da177e4 | 491 | int retval; |
bf36b901 AM |
492 | |
493 | if ((key >= '0') && (key <= '9')) | |
1da177e4 | 494 | retval = key - '0'; |
bf36b901 | 495 | else if ((key >= 'a') && (key <= 'z')) |
1da177e4 | 496 | retval = key + 10 - 'a'; |
bf36b901 | 497 | else |
1da177e4 | 498 | retval = -1; |
1da177e4 LT |
499 | return retval; |
500 | } | |
501 | ||
502 | /* | |
503 | * get and put functions for the table, exposed to modules. | |
504 | */ | |
bf36b901 AM |
505 | struct sysrq_key_op *__sysrq_get_key_op(int key) |
506 | { | |
507 | struct sysrq_key_op *op_p = NULL; | |
1da177e4 | 508 | int i; |
bf36b901 | 509 | |
1da177e4 | 510 | i = sysrq_key_table_key2index(key); |
bf36b901 AM |
511 | if (i != -1) |
512 | op_p = sysrq_key_table[i]; | |
97f5f0cd | 513 | |
1da177e4 LT |
514 | return op_p; |
515 | } | |
516 | ||
bf36b901 AM |
517 | static void __sysrq_put_key_op(int key, struct sysrq_key_op *op_p) |
518 | { | |
519 | int i = sysrq_key_table_key2index(key); | |
1da177e4 | 520 | |
1da177e4 LT |
521 | if (i != -1) |
522 | sysrq_key_table[i] = op_p; | |
523 | } | |
524 | ||
f335397d | 525 | void __handle_sysrq(int key, bool check_mask) |
1da177e4 LT |
526 | { |
527 | struct sysrq_key_op *op_p; | |
528 | int orig_log_level; | |
bf36b901 | 529 | int i; |
1da177e4 | 530 | |
722773af | 531 | rcu_sysrq_start(); |
984d74a7 | 532 | rcu_read_lock(); |
fb144adc AW |
533 | /* |
534 | * Raise the apparent loglevel to maximum so that the sysrq header | |
535 | * is shown to provide the user with positive feedback. We do not | |
536 | * simply emit this at KERN_EMERG as that would change message | |
537 | * routing in the consumers of /proc/kmsg. | |
538 | */ | |
1da177e4 | 539 | orig_log_level = console_loglevel; |
a8fe19eb | 540 | console_loglevel = CONSOLE_LOGLEVEL_DEFAULT; |
401e4a7c | 541 | pr_info("SysRq : "); |
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)) { |
401e4a7c | 550 | pr_cont("%s\n", op_p->action_msg); |
1da177e4 | 551 | console_loglevel = orig_log_level; |
1495cc9d | 552 | op_p->handler(key); |
bf36b901 | 553 | } else { |
401e4a7c | 554 | pr_cont("This sysrq operation is disabled.\n"); |
bf36b901 | 555 | } |
1da177e4 | 556 | } else { |
401e4a7c | 557 | pr_cont("HELP : "); |
1da177e4 | 558 | /* Only print the help msg once per handler */ |
bf36b901 AM |
559 | for (i = 0; i < ARRAY_SIZE(sysrq_key_table); i++) { |
560 | if (sysrq_key_table[i]) { | |
561 | int j; | |
562 | ||
563 | for (j = 0; sysrq_key_table[i] != | |
564 | sysrq_key_table[j]; j++) | |
565 | ; | |
566 | if (j != i) | |
567 | continue; | |
401e4a7c | 568 | pr_cont("%s ", sysrq_key_table[i]->help_msg); |
bf36b901 | 569 | } |
1da177e4 | 570 | } |
401e4a7c | 571 | pr_cont("\n"); |
1da177e4 LT |
572 | console_loglevel = orig_log_level; |
573 | } | |
984d74a7 | 574 | rcu_read_unlock(); |
722773af | 575 | rcu_sysrq_end(); |
1da177e4 LT |
576 | } |
577 | ||
f335397d | 578 | void handle_sysrq(int key) |
1da177e4 | 579 | { |
5d6f647f | 580 | if (sysrq_on()) |
f335397d | 581 | __handle_sysrq(key, true); |
1da177e4 | 582 | } |
bf36b901 | 583 | EXPORT_SYMBOL(handle_sysrq); |
1da177e4 | 584 | |
97f5f0cd | 585 | #ifdef CONFIG_INPUT |
ffb6e0c9 | 586 | static int sysrq_reset_downtime_ms; |
97f5f0cd DT |
587 | |
588 | /* Simple translation table for the SysRq keys */ | |
fcb71930 | 589 | static const unsigned char sysrq_xlate[KEY_CNT] = |
97f5f0cd DT |
590 | "\000\0331234567890-=\177\t" /* 0x00 - 0x0f */ |
591 | "qwertyuiop[]\r\000as" /* 0x10 - 0x1f */ | |
592 | "dfghjkl;'`\000\\zxcv" /* 0x20 - 0x2f */ | |
593 | "bnm,./\000*\000 \000\201\202\203\204\205" /* 0x30 - 0x3f */ | |
594 | "\206\207\210\211\212\000\000789-456+1" /* 0x40 - 0x4f */ | |
595 | "230\177\000\000\213\214\000\000\000\000\000\000\000\000\000\000" /* 0x50 - 0x5f */ | |
596 | "\r\000/"; /* 0x60 - 0x6f */ | |
597 | ||
fcb71930 DT |
598 | struct sysrq_state { |
599 | struct input_handle handle; | |
600 | struct work_struct reinject_work; | |
601 | unsigned long key_down[BITS_TO_LONGS(KEY_CNT)]; | |
602 | unsigned int alt; | |
603 | unsigned int alt_use; | |
604 | bool active; | |
605 | bool need_reinject; | |
7ab7b5ad | 606 | bool reinjecting; |
154b7a48 MP |
607 | |
608 | /* reset sequence handling */ | |
609 | bool reset_canceled; | |
3d289517 | 610 | bool reset_requested; |
154b7a48 MP |
611 | unsigned long reset_keybit[BITS_TO_LONGS(KEY_CNT)]; |
612 | int reset_seq_len; | |
613 | int reset_seq_cnt; | |
614 | int reset_seq_version; | |
39030786 | 615 | struct timer_list keyreset_timer; |
fcb71930 DT |
616 | }; |
617 | ||
154b7a48 MP |
618 | #define SYSRQ_KEY_RESET_MAX 20 /* Should be plenty */ |
619 | static unsigned short sysrq_reset_seq[SYSRQ_KEY_RESET_MAX]; | |
620 | static unsigned int sysrq_reset_seq_len; | |
621 | static unsigned int sysrq_reset_seq_version = 1; | |
622 | ||
623 | static void sysrq_parse_reset_sequence(struct sysrq_state *state) | |
624 | { | |
625 | int i; | |
626 | unsigned short key; | |
627 | ||
628 | state->reset_seq_cnt = 0; | |
629 | ||
630 | for (i = 0; i < sysrq_reset_seq_len; i++) { | |
631 | key = sysrq_reset_seq[i]; | |
632 | ||
633 | if (key == KEY_RESERVED || key > KEY_MAX) | |
634 | break; | |
635 | ||
636 | __set_bit(key, state->reset_keybit); | |
637 | state->reset_seq_len++; | |
638 | ||
639 | if (test_bit(key, state->key_down)) | |
640 | state->reset_seq_cnt++; | |
641 | } | |
642 | ||
643 | /* Disable reset until old keys are not released */ | |
644 | state->reset_canceled = state->reset_seq_cnt != 0; | |
645 | ||
646 | state->reset_seq_version = sysrq_reset_seq_version; | |
647 | } | |
648 | ||
3d289517 | 649 | static void sysrq_do_reset(unsigned long _state) |
39030786 | 650 | { |
3d289517 MP |
651 | struct sysrq_state *state = (struct sysrq_state *) _state; |
652 | ||
653 | state->reset_requested = true; | |
654 | ||
655 | sys_sync(); | |
656 | kernel_restart(NULL); | |
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 | |
3d289517 | 668 | sysrq_do_reset((unsigned long)state); |
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); | |
731 | } | |
732 | #else | |
733 | static void sysrq_of_get_keyreset_config(void) | |
734 | { | |
735 | } | |
736 | #endif | |
737 | ||
fcb71930 DT |
738 | static void sysrq_reinject_alt_sysrq(struct work_struct *work) |
739 | { | |
740 | struct sysrq_state *sysrq = | |
741 | container_of(work, struct sysrq_state, reinject_work); | |
742 | struct input_handle *handle = &sysrq->handle; | |
743 | unsigned int alt_code = sysrq->alt_use; | |
744 | ||
745 | if (sysrq->need_reinject) { | |
7ab7b5ad DT |
746 | /* we do not want the assignment to be reordered */ |
747 | sysrq->reinjecting = true; | |
748 | mb(); | |
749 | ||
fcb71930 DT |
750 | /* Simulate press and release of Alt + SysRq */ |
751 | input_inject_event(handle, EV_KEY, alt_code, 1); | |
752 | input_inject_event(handle, EV_KEY, KEY_SYSRQ, 1); | |
753 | input_inject_event(handle, EV_SYN, SYN_REPORT, 1); | |
754 | ||
755 | input_inject_event(handle, EV_KEY, KEY_SYSRQ, 0); | |
756 | input_inject_event(handle, EV_KEY, alt_code, 0); | |
757 | input_inject_event(handle, EV_SYN, SYN_REPORT, 1); | |
7ab7b5ad DT |
758 | |
759 | mb(); | |
760 | sysrq->reinjecting = false; | |
fcb71930 DT |
761 | } |
762 | } | |
97f5f0cd | 763 | |
154b7a48 MP |
764 | static bool sysrq_handle_keypress(struct sysrq_state *sysrq, |
765 | unsigned int code, int value) | |
97f5f0cd | 766 | { |
fcb71930 | 767 | bool was_active = sysrq->active; |
1966cb22 DT |
768 | bool suppress; |
769 | ||
154b7a48 | 770 | switch (code) { |
7ab7b5ad | 771 | |
154b7a48 MP |
772 | case KEY_LEFTALT: |
773 | case KEY_RIGHTALT: | |
774 | if (!value) { | |
775 | /* One of ALTs is being released */ | |
776 | if (sysrq->active && code == sysrq->alt_use) | |
777 | sysrq->active = false; | |
1966cb22 | 778 | |
154b7a48 MP |
779 | sysrq->alt = KEY_RESERVED; |
780 | ||
781 | } else if (value != 2) { | |
782 | sysrq->alt = code; | |
783 | sysrq->need_reinject = false; | |
784 | } | |
fcb71930 | 785 | break; |
97f5f0cd | 786 | |
154b7a48 MP |
787 | case KEY_SYSRQ: |
788 | if (value == 1 && sysrq->alt != KEY_RESERVED) { | |
789 | sysrq->active = true; | |
790 | sysrq->alt_use = sysrq->alt; | |
791 | /* | |
792 | * If nothing else will be pressed we'll need | |
793 | * to re-inject Alt-SysRq keysroke. | |
794 | */ | |
795 | sysrq->need_reinject = true; | |
796 | } | |
97f5f0cd | 797 | |
154b7a48 MP |
798 | /* |
799 | * Pretend that sysrq was never pressed at all. This | |
800 | * is needed to properly handle KGDB which will try | |
801 | * to release all keys after exiting debugger. If we | |
802 | * do not clear key bit it KGDB will end up sending | |
803 | * release events for Alt and SysRq, potentially | |
804 | * triggering print screen function. | |
805 | */ | |
806 | if (sysrq->active) | |
807 | clear_bit(KEY_SYSRQ, sysrq->handle.dev->key); | |
f5dec511 | 808 | |
154b7a48 | 809 | break; |
fcb71930 | 810 | |
154b7a48 MP |
811 | default: |
812 | if (sysrq->active && value && value != 2) { | |
813 | sysrq->need_reinject = false; | |
814 | __handle_sysrq(sysrq_xlate[code], true); | |
815 | } | |
816 | break; | |
817 | } | |
fcb71930 | 818 | |
154b7a48 | 819 | suppress = sysrq->active; |
fcb71930 | 820 | |
154b7a48 | 821 | if (!sysrq->active) { |
fcb71930 | 822 | |
154b7a48 MP |
823 | /* |
824 | * See if reset sequence has changed since the last time. | |
825 | */ | |
826 | if (sysrq->reset_seq_version != sysrq_reset_seq_version) | |
827 | sysrq_parse_reset_sequence(sysrq); | |
fcb71930 | 828 | |
154b7a48 MP |
829 | /* |
830 | * If we are not suppressing key presses keep track of | |
831 | * keyboard state so we can release keys that have been | |
832 | * pressed before entering SysRq mode. | |
833 | */ | |
834 | if (value) | |
835 | set_bit(code, sysrq->key_down); | |
836 | else | |
837 | clear_bit(code, sysrq->key_down); | |
838 | ||
839 | if (was_active) | |
840 | schedule_work(&sysrq->reinject_work); | |
841 | ||
39030786 MP |
842 | /* Check for reset sequence */ |
843 | sysrq_detect_reset_sequence(sysrq, code, value); | |
97f5f0cd | 844 | |
154b7a48 MP |
845 | } else if (value == 0 && test_and_clear_bit(code, sysrq->key_down)) { |
846 | /* | |
847 | * Pass on release events for keys that was pressed before | |
848 | * entering SysRq mode. | |
849 | */ | |
850 | suppress = false; | |
851 | } | |
fcb71930 | 852 | |
154b7a48 MP |
853 | return suppress; |
854 | } | |
fcb71930 | 855 | |
154b7a48 MP |
856 | static bool sysrq_filter(struct input_handle *handle, |
857 | unsigned int type, unsigned int code, int value) | |
858 | { | |
859 | struct sysrq_state *sysrq = handle->private; | |
860 | bool suppress; | |
fcb71930 | 861 | |
154b7a48 MP |
862 | /* |
863 | * Do not filter anything if we are in the process of re-injecting | |
864 | * Alt+SysRq combination. | |
865 | */ | |
866 | if (sysrq->reinjecting) | |
867 | return false; | |
868 | ||
869 | switch (type) { | |
870 | ||
871 | case EV_SYN: | |
872 | suppress = false; | |
873 | break; | |
874 | ||
875 | case EV_KEY: | |
876 | suppress = sysrq_handle_keypress(sysrq, code, value); | |
97f5f0cd DT |
877 | break; |
878 | ||
879 | default: | |
fcb71930 | 880 | suppress = sysrq->active; |
97f5f0cd DT |
881 | break; |
882 | } | |
883 | ||
1966cb22 | 884 | return suppress; |
97f5f0cd DT |
885 | } |
886 | ||
887 | static int sysrq_connect(struct input_handler *handler, | |
888 | struct input_dev *dev, | |
889 | const struct input_device_id *id) | |
890 | { | |
fcb71930 | 891 | struct sysrq_state *sysrq; |
97f5f0cd DT |
892 | int error; |
893 | ||
fcb71930 DT |
894 | sysrq = kzalloc(sizeof(struct sysrq_state), GFP_KERNEL); |
895 | if (!sysrq) | |
97f5f0cd DT |
896 | return -ENOMEM; |
897 | ||
fcb71930 DT |
898 | INIT_WORK(&sysrq->reinject_work, sysrq_reinject_alt_sysrq); |
899 | ||
900 | sysrq->handle.dev = dev; | |
901 | sysrq->handle.handler = handler; | |
902 | sysrq->handle.name = "sysrq"; | |
903 | sysrq->handle.private = sysrq; | |
3d289517 MP |
904 | setup_timer(&sysrq->keyreset_timer, |
905 | sysrq_do_reset, (unsigned long)sysrq); | |
97f5f0cd | 906 | |
fcb71930 | 907 | error = input_register_handle(&sysrq->handle); |
97f5f0cd DT |
908 | if (error) { |
909 | pr_err("Failed to register input sysrq handler, error %d\n", | |
910 | error); | |
911 | goto err_free; | |
912 | } | |
913 | ||
fcb71930 | 914 | error = input_open_device(&sysrq->handle); |
97f5f0cd DT |
915 | if (error) { |
916 | pr_err("Failed to open input device, error %d\n", error); | |
917 | goto err_unregister; | |
918 | } | |
919 | ||
920 | return 0; | |
921 | ||
922 | err_unregister: | |
fcb71930 | 923 | input_unregister_handle(&sysrq->handle); |
97f5f0cd | 924 | err_free: |
fcb71930 | 925 | kfree(sysrq); |
97f5f0cd DT |
926 | return error; |
927 | } | |
928 | ||
929 | static void sysrq_disconnect(struct input_handle *handle) | |
930 | { | |
fcb71930 DT |
931 | struct sysrq_state *sysrq = handle->private; |
932 | ||
97f5f0cd | 933 | input_close_device(handle); |
fcb71930 | 934 | cancel_work_sync(&sysrq->reinject_work); |
39030786 | 935 | del_timer_sync(&sysrq->keyreset_timer); |
97f5f0cd | 936 | input_unregister_handle(handle); |
fcb71930 | 937 | kfree(sysrq); |
97f5f0cd DT |
938 | } |
939 | ||
940 | /* | |
1966cb22 DT |
941 | * We are matching on KEY_LEFTALT instead of KEY_SYSRQ because not all |
942 | * keyboards have SysRq key predefined and so user may add it to keymap | |
97f5f0cd DT |
943 | * later, but we expect all such keyboards to have left alt. |
944 | */ | |
945 | static const struct input_device_id sysrq_ids[] = { | |
946 | { | |
947 | .flags = INPUT_DEVICE_ID_MATCH_EVBIT | | |
948 | INPUT_DEVICE_ID_MATCH_KEYBIT, | |
949 | .evbit = { BIT_MASK(EV_KEY) }, | |
950 | .keybit = { BIT_MASK(KEY_LEFTALT) }, | |
951 | }, | |
952 | { }, | |
953 | }; | |
954 | ||
955 | static struct input_handler sysrq_handler = { | |
956 | .filter = sysrq_filter, | |
957 | .connect = sysrq_connect, | |
958 | .disconnect = sysrq_disconnect, | |
959 | .name = "sysrq", | |
960 | .id_table = sysrq_ids, | |
961 | }; | |
962 | ||
963 | static bool sysrq_handler_registered; | |
964 | ||
965 | static inline void sysrq_register_handler(void) | |
966 | { | |
967 | int error; | |
968 | ||
4c076eb0 MP |
969 | sysrq_of_get_keyreset_config(); |
970 | ||
97f5f0cd DT |
971 | error = input_register_handler(&sysrq_handler); |
972 | if (error) | |
973 | pr_err("Failed to register input handler, error %d", error); | |
974 | else | |
975 | sysrq_handler_registered = true; | |
976 | } | |
977 | ||
978 | static inline void sysrq_unregister_handler(void) | |
979 | { | |
980 | if (sysrq_handler_registered) { | |
981 | input_unregister_handler(&sysrq_handler); | |
982 | sysrq_handler_registered = false; | |
983 | } | |
984 | } | |
985 | ||
154b7a48 MP |
986 | static int sysrq_reset_seq_param_set(const char *buffer, |
987 | const struct kernel_param *kp) | |
988 | { | |
989 | unsigned long val; | |
990 | int error; | |
991 | ||
86b40567 | 992 | error = kstrtoul(buffer, 0, &val); |
154b7a48 MP |
993 | if (error < 0) |
994 | return error; | |
995 | ||
996 | if (val > KEY_MAX) | |
997 | return -EINVAL; | |
998 | ||
999 | *((unsigned short *)kp->arg) = val; | |
1000 | sysrq_reset_seq_version++; | |
1001 | ||
1002 | return 0; | |
1003 | } | |
1004 | ||
9c27847d | 1005 | static const struct kernel_param_ops param_ops_sysrq_reset_seq = { |
154b7a48 MP |
1006 | .get = param_get_ushort, |
1007 | .set = sysrq_reset_seq_param_set, | |
1008 | }; | |
1009 | ||
1010 | #define param_check_sysrq_reset_seq(name, p) \ | |
1011 | __param_check(name, p, unsigned short) | |
1012 | ||
3bce6f64 PG |
1013 | /* |
1014 | * not really modular, but the easiest way to keep compat with existing | |
1015 | * bootargs behaviour is to continue using module_param here. | |
1016 | */ | |
154b7a48 MP |
1017 | module_param_array_named(reset_seq, sysrq_reset_seq, sysrq_reset_seq, |
1018 | &sysrq_reset_seq_len, 0644); | |
1019 | ||
39030786 MP |
1020 | module_param_named(sysrq_downtime_ms, sysrq_reset_downtime_ms, int, 0644); |
1021 | ||
97f5f0cd DT |
1022 | #else |
1023 | ||
1024 | static inline void sysrq_register_handler(void) | |
1025 | { | |
1026 | } | |
1027 | ||
1028 | static inline void sysrq_unregister_handler(void) | |
1029 | { | |
1030 | } | |
1031 | ||
1032 | #endif /* CONFIG_INPUT */ | |
1033 | ||
1034 | int sysrq_toggle_support(int enable_mask) | |
1035 | { | |
1036 | bool was_enabled = sysrq_on(); | |
1037 | ||
1038 | sysrq_enabled = enable_mask; | |
1039 | ||
1040 | if (was_enabled != sysrq_on()) { | |
1041 | if (sysrq_on()) | |
1042 | sysrq_register_handler(); | |
1043 | else | |
1044 | sysrq_unregister_handler(); | |
1045 | } | |
1046 | ||
1047 | return 0; | |
1048 | } | |
1049 | ||
cf62ddce | 1050 | static int __sysrq_swap_key_ops(int key, struct sysrq_key_op *insert_op_p, |
bf36b901 AM |
1051 | struct sysrq_key_op *remove_op_p) |
1052 | { | |
1da177e4 | 1053 | int retval; |
1da177e4 | 1054 | |
984d74a7 | 1055 | spin_lock(&sysrq_key_table_lock); |
1da177e4 LT |
1056 | if (__sysrq_get_key_op(key) == remove_op_p) { |
1057 | __sysrq_put_key_op(key, insert_op_p); | |
1058 | retval = 0; | |
1059 | } else { | |
1060 | retval = -1; | |
1061 | } | |
984d74a7 RR |
1062 | spin_unlock(&sysrq_key_table_lock); |
1063 | ||
1064 | /* | |
1065 | * A concurrent __handle_sysrq either got the old op or the new op. | |
1066 | * Wait for it to go away before returning, so the code for an old | |
1067 | * op is not freed (eg. on module unload) while it is in use. | |
1068 | */ | |
1069 | synchronize_rcu(); | |
1070 | ||
1da177e4 LT |
1071 | return retval; |
1072 | } | |
1073 | ||
1074 | int register_sysrq_key(int key, struct sysrq_key_op *op_p) | |
1075 | { | |
1076 | return __sysrq_swap_key_ops(key, op_p, NULL); | |
1077 | } | |
bf36b901 | 1078 | EXPORT_SYMBOL(register_sysrq_key); |
1da177e4 LT |
1079 | |
1080 | int unregister_sysrq_key(int key, struct sysrq_key_op *op_p) | |
1081 | { | |
1082 | return __sysrq_swap_key_ops(key, NULL, op_p); | |
1083 | } | |
1da177e4 | 1084 | EXPORT_SYMBOL(unregister_sysrq_key); |
f40cbaa5 AD |
1085 | |
1086 | #ifdef CONFIG_PROC_FS | |
1087 | /* | |
1088 | * writing 'C' to /proc/sysrq-trigger is like sysrq-C | |
1089 | */ | |
1090 | static ssize_t write_sysrq_trigger(struct file *file, const char __user *buf, | |
1091 | size_t count, loff_t *ppos) | |
1092 | { | |
1093 | if (count) { | |
1094 | char c; | |
1095 | ||
1096 | if (get_user(c, buf)) | |
1097 | return -EFAULT; | |
f335397d | 1098 | __handle_sysrq(c, false); |
f40cbaa5 | 1099 | } |
97f5f0cd | 1100 | |
f40cbaa5 AD |
1101 | return count; |
1102 | } | |
1103 | ||
1104 | static const struct file_operations proc_sysrq_trigger_operations = { | |
1105 | .write = write_sysrq_trigger, | |
6038f373 | 1106 | .llseek = noop_llseek, |
f40cbaa5 AD |
1107 | }; |
1108 | ||
97f5f0cd DT |
1109 | static void sysrq_init_procfs(void) |
1110 | { | |
1111 | if (!proc_create("sysrq-trigger", S_IWUSR, NULL, | |
1112 | &proc_sysrq_trigger_operations)) | |
1113 | pr_err("Failed to register proc interface\n"); | |
1114 | } | |
1115 | ||
1116 | #else | |
1117 | ||
1118 | static inline void sysrq_init_procfs(void) | |
1119 | { | |
1120 | } | |
1121 | ||
1122 | #endif /* CONFIG_PROC_FS */ | |
1123 | ||
f40cbaa5 AD |
1124 | static int __init sysrq_init(void) |
1125 | { | |
97f5f0cd DT |
1126 | sysrq_init_procfs(); |
1127 | ||
1128 | if (sysrq_on()) | |
1129 | sysrq_register_handler(); | |
1130 | ||
f40cbaa5 AD |
1131 | return 0; |
1132 | } | |
3bce6f64 | 1133 | device_initcall(sysrq_init); |