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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> |
1da177e4 LT |
46 | |
47 | #include <asm/ptrace.h> | |
2033b0c3 | 48 | #include <asm/irq_regs.h> |
1da177e4 LT |
49 | |
50 | /* Whether we react on sysrq keys or just ignore them */ | |
8c6a98b2 | 51 | static int __read_mostly sysrq_enabled = SYSRQ_DEFAULT_ENABLE; |
97f5f0cd | 52 | static bool __read_mostly sysrq_always_enabled; |
5d6f647f | 53 | |
97f5f0cd | 54 | static bool sysrq_on(void) |
5d6f647f | 55 | { |
97f5f0cd | 56 | return sysrq_enabled || sysrq_always_enabled; |
5d6f647f IM |
57 | } |
58 | ||
59 | /* | |
60 | * A value of 1 means 'all', other nonzero values are an op mask: | |
61 | */ | |
97f5f0cd | 62 | static bool sysrq_on_mask(int mask) |
5d6f647f | 63 | { |
97f5f0cd DT |
64 | return sysrq_always_enabled || |
65 | sysrq_enabled == 1 || | |
66 | (sysrq_enabled & mask); | |
5d6f647f IM |
67 | } |
68 | ||
69 | static int __init sysrq_always_enabled_setup(char *str) | |
70 | { | |
97f5f0cd DT |
71 | sysrq_always_enabled = true; |
72 | pr_info("sysrq always enabled.\n"); | |
5d6f647f IM |
73 | |
74 | return 1; | |
75 | } | |
76 | ||
77 | __setup("sysrq_always_enabled", sysrq_always_enabled_setup); | |
78 | ||
1da177e4 | 79 | |
1495cc9d | 80 | static void sysrq_handle_loglevel(int key) |
1da177e4 LT |
81 | { |
82 | int i; | |
97f5f0cd | 83 | |
1da177e4 LT |
84 | i = key - '0'; |
85 | console_loglevel = 7; | |
86 | printk("Loglevel set to %d\n", i); | |
87 | console_loglevel = i; | |
bf36b901 | 88 | } |
1da177e4 LT |
89 | static struct sysrq_key_op sysrq_loglevel_op = { |
90 | .handler = sysrq_handle_loglevel, | |
208b95ce | 91 | .help_msg = "loglevel(0-9)", |
1da177e4 LT |
92 | .action_msg = "Changing Loglevel", |
93 | .enable_mask = SYSRQ_ENABLE_LOG, | |
94 | }; | |
95 | ||
1da177e4 | 96 | #ifdef CONFIG_VT |
1495cc9d | 97 | static void sysrq_handle_SAK(int key) |
1da177e4 | 98 | { |
8b6312f4 | 99 | struct work_struct *SAK_work = &vc_cons[fg_console].SAK_work; |
8b6312f4 | 100 | schedule_work(SAK_work); |
1da177e4 LT |
101 | } |
102 | static struct sysrq_key_op sysrq_SAK_op = { | |
103 | .handler = sysrq_handle_SAK, | |
104 | .help_msg = "saK", | |
105 | .action_msg = "SAK", | |
106 | .enable_mask = SYSRQ_ENABLE_KEYBOARD, | |
107 | }; | |
bf36b901 | 108 | #else |
97f5f0cd | 109 | #define sysrq_SAK_op (*(struct sysrq_key_op *)NULL) |
1da177e4 LT |
110 | #endif |
111 | ||
112 | #ifdef CONFIG_VT | |
1495cc9d | 113 | static void sysrq_handle_unraw(int key) |
1da177e4 | 114 | { |
079c9534 | 115 | vt_reset_unicode(fg_console); |
1da177e4 | 116 | } |
079c9534 | 117 | |
1da177e4 LT |
118 | static struct sysrq_key_op sysrq_unraw_op = { |
119 | .handler = sysrq_handle_unraw, | |
120 | .help_msg = "unRaw", | |
2e8ecb9d | 121 | .action_msg = "Keyboard mode set to system default", |
1da177e4 LT |
122 | .enable_mask = SYSRQ_ENABLE_KEYBOARD, |
123 | }; | |
bf36b901 | 124 | #else |
97f5f0cd | 125 | #define sysrq_unraw_op (*(struct sysrq_key_op *)NULL) |
1da177e4 LT |
126 | #endif /* CONFIG_VT */ |
127 | ||
1495cc9d | 128 | static void sysrq_handle_crash(int key) |
86b1ae38 | 129 | { |
d6580a9f | 130 | char *killer = NULL; |
cab8bd34 HS |
131 | |
132 | panic_on_oops = 1; /* force panic */ | |
133 | wmb(); | |
d6580a9f | 134 | *killer = 1; |
86b1ae38 | 135 | } |
cab8bd34 | 136 | static struct sysrq_key_op sysrq_crash_op = { |
d6580a9f NH |
137 | .handler = sysrq_handle_crash, |
138 | .help_msg = "Crash", | |
139 | .action_msg = "Trigger a crash", | |
86b1ae38 HN |
140 | .enable_mask = SYSRQ_ENABLE_DUMP, |
141 | }; | |
86b1ae38 | 142 | |
1495cc9d | 143 | static void sysrq_handle_reboot(int key) |
1da177e4 | 144 | { |
b2e9c7d0 | 145 | lockdep_off(); |
1da177e4 | 146 | local_irq_enable(); |
4de8b9b7 | 147 | emergency_restart(); |
1da177e4 | 148 | } |
1da177e4 LT |
149 | static struct sysrq_key_op sysrq_reboot_op = { |
150 | .handler = sysrq_handle_reboot, | |
151 | .help_msg = "reBoot", | |
152 | .action_msg = "Resetting", | |
153 | .enable_mask = SYSRQ_ENABLE_BOOT, | |
154 | }; | |
155 | ||
1495cc9d | 156 | static void sysrq_handle_sync(int key) |
1da177e4 LT |
157 | { |
158 | emergency_sync(); | |
159 | } | |
1da177e4 LT |
160 | static struct sysrq_key_op sysrq_sync_op = { |
161 | .handler = sysrq_handle_sync, | |
162 | .help_msg = "Sync", | |
163 | .action_msg = "Emergency Sync", | |
164 | .enable_mask = SYSRQ_ENABLE_SYNC, | |
165 | }; | |
166 | ||
1495cc9d | 167 | static void sysrq_handle_show_timers(int key) |
88ad0bf6 IM |
168 | { |
169 | sysrq_timer_list_show(); | |
170 | } | |
171 | ||
172 | static struct sysrq_key_op sysrq_show_timers_op = { | |
173 | .handler = sysrq_handle_show_timers, | |
174 | .help_msg = "show-all-timers(Q)", | |
322acf65 | 175 | .action_msg = "Show clockevent devices & pending hrtimers (no others)", |
88ad0bf6 IM |
176 | }; |
177 | ||
1495cc9d | 178 | static void sysrq_handle_mountro(int key) |
1da177e4 LT |
179 | { |
180 | emergency_remount(); | |
181 | } | |
1da177e4 LT |
182 | static struct sysrq_key_op sysrq_mountro_op = { |
183 | .handler = sysrq_handle_mountro, | |
184 | .help_msg = "Unmount", | |
185 | .action_msg = "Emergency Remount R/O", | |
186 | .enable_mask = SYSRQ_ENABLE_REMOUNT, | |
187 | }; | |
188 | ||
8c64580d | 189 | #ifdef CONFIG_LOCKDEP |
1495cc9d | 190 | static void sysrq_handle_showlocks(int key) |
de5097c2 | 191 | { |
9a11b49a | 192 | debug_show_all_locks(); |
de5097c2 | 193 | } |
8c64580d | 194 | |
de5097c2 IM |
195 | static struct sysrq_key_op sysrq_showlocks_op = { |
196 | .handler = sysrq_handle_showlocks, | |
197 | .help_msg = "show-all-locks(D)", | |
198 | .action_msg = "Show Locks Held", | |
199 | }; | |
bf36b901 | 200 | #else |
97f5f0cd | 201 | #define sysrq_showlocks_op (*(struct sysrq_key_op *)NULL) |
de5097c2 | 202 | #endif |
1da177e4 | 203 | |
5045bcae RR |
204 | #ifdef CONFIG_SMP |
205 | static DEFINE_SPINLOCK(show_lock); | |
206 | ||
207 | static void showacpu(void *dummy) | |
208 | { | |
209 | unsigned long flags; | |
210 | ||
211 | /* Idle CPUs have no interesting backtrace. */ | |
212 | if (idle_cpu(smp_processor_id())) | |
213 | return; | |
214 | ||
215 | spin_lock_irqsave(&show_lock, flags); | |
216 | printk(KERN_INFO "CPU%d:\n", smp_processor_id()); | |
217 | show_stack(NULL, NULL); | |
218 | spin_unlock_irqrestore(&show_lock, flags); | |
219 | } | |
220 | ||
221 | static void sysrq_showregs_othercpus(struct work_struct *dummy) | |
222 | { | |
8b604d52 | 223 | smp_call_function(showacpu, NULL, 0); |
5045bcae RR |
224 | } |
225 | ||
226 | static DECLARE_WORK(sysrq_showallcpus, sysrq_showregs_othercpus); | |
227 | ||
1495cc9d | 228 | static void sysrq_handle_showallcpus(int key) |
5045bcae | 229 | { |
47cab6a7 IM |
230 | /* |
231 | * Fall back to the workqueue based printing if the | |
232 | * backtrace printing did not succeed or the | |
233 | * architecture has no support for it: | |
234 | */ | |
235 | if (!trigger_all_cpu_backtrace()) { | |
236 | struct pt_regs *regs = get_irq_regs(); | |
237 | ||
238 | if (regs) { | |
239 | printk(KERN_INFO "CPU%d:\n", smp_processor_id()); | |
240 | show_regs(regs); | |
241 | } | |
242 | schedule_work(&sysrq_showallcpus); | |
243 | } | |
5045bcae RR |
244 | } |
245 | ||
246 | static struct sysrq_key_op sysrq_showallcpus_op = { | |
247 | .handler = sysrq_handle_showallcpus, | |
208b95ce | 248 | .help_msg = "show-backtrace-all-active-cpus(L)", |
5045bcae RR |
249 | .action_msg = "Show backtrace of all active CPUs", |
250 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
251 | }; | |
252 | #endif | |
253 | ||
1495cc9d | 254 | static void sysrq_handle_showregs(int key) |
1da177e4 | 255 | { |
7d12e780 DH |
256 | struct pt_regs *regs = get_irq_regs(); |
257 | if (regs) | |
258 | show_regs(regs); | |
cdd6c482 | 259 | perf_event_print_debug(); |
1da177e4 LT |
260 | } |
261 | static struct sysrq_key_op sysrq_showregs_op = { | |
262 | .handler = sysrq_handle_showregs, | |
208b95ce | 263 | .help_msg = "show-registers(P)", |
1da177e4 LT |
264 | .action_msg = "Show Regs", |
265 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
266 | }; | |
267 | ||
1495cc9d | 268 | static void sysrq_handle_showstate(int key) |
1da177e4 LT |
269 | { |
270 | show_state(); | |
271 | } | |
272 | static struct sysrq_key_op sysrq_showstate_op = { | |
273 | .handler = sysrq_handle_showstate, | |
208b95ce | 274 | .help_msg = "show-task-states(T)", |
1da177e4 LT |
275 | .action_msg = "Show State", |
276 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
277 | }; | |
278 | ||
1495cc9d | 279 | static void sysrq_handle_showstate_blocked(int key) |
e59e2ae2 IM |
280 | { |
281 | show_state_filter(TASK_UNINTERRUPTIBLE); | |
282 | } | |
283 | static struct sysrq_key_op sysrq_showstate_blocked_op = { | |
284 | .handler = sysrq_handle_showstate_blocked, | |
208b95ce | 285 | .help_msg = "show-blocked-tasks(W)", |
e59e2ae2 IM |
286 | .action_msg = "Show Blocked State", |
287 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
288 | }; | |
289 | ||
69f698ad PZ |
290 | #ifdef CONFIG_TRACING |
291 | #include <linux/ftrace.h> | |
292 | ||
1495cc9d | 293 | static void sysrq_ftrace_dump(int key) |
69f698ad | 294 | { |
cecbca96 | 295 | ftrace_dump(DUMP_ALL); |
69f698ad PZ |
296 | } |
297 | static struct sysrq_key_op sysrq_ftrace_dump_op = { | |
298 | .handler = sysrq_ftrace_dump, | |
3871f2ff | 299 | .help_msg = "dump-ftrace-buffer(Z)", |
69f698ad PZ |
300 | .action_msg = "Dump ftrace buffer", |
301 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
302 | }; | |
303 | #else | |
97f5f0cd | 304 | #define sysrq_ftrace_dump_op (*(struct sysrq_key_op *)NULL) |
69f698ad | 305 | #endif |
e59e2ae2 | 306 | |
1495cc9d | 307 | static void sysrq_handle_showmem(int key) |
1da177e4 | 308 | { |
b2b755b5 | 309 | show_mem(0); |
1da177e4 LT |
310 | } |
311 | static struct sysrq_key_op sysrq_showmem_op = { | |
312 | .handler = sysrq_handle_showmem, | |
208b95ce | 313 | .help_msg = "show-memory-usage(M)", |
1da177e4 LT |
314 | .action_msg = "Show Memory", |
315 | .enable_mask = SYSRQ_ENABLE_DUMP, | |
316 | }; | |
317 | ||
bf36b901 AM |
318 | /* |
319 | * Signal sysrq helper function. Sends a signal to all user processes. | |
320 | */ | |
1da177e4 LT |
321 | static void send_sig_all(int sig) |
322 | { | |
323 | struct task_struct *p; | |
324 | ||
e502babe | 325 | read_lock(&tasklist_lock); |
1da177e4 | 326 | for_each_process(p) { |
d3a532a9 AV |
327 | if (p->flags & PF_KTHREAD) |
328 | continue; | |
329 | if (is_global_init(p)) | |
330 | continue; | |
331 | ||
b82c3287 | 332 | do_send_sig_info(sig, SEND_SIG_FORCED, p, true); |
1da177e4 | 333 | } |
e502babe | 334 | read_unlock(&tasklist_lock); |
1da177e4 LT |
335 | } |
336 | ||
1495cc9d | 337 | static void sysrq_handle_term(int key) |
1da177e4 LT |
338 | { |
339 | send_sig_all(SIGTERM); | |
340 | console_loglevel = 8; | |
341 | } | |
342 | static struct sysrq_key_op sysrq_term_op = { | |
343 | .handler = sysrq_handle_term, | |
208b95ce | 344 | .help_msg = "terminate-all-tasks(E)", |
1da177e4 LT |
345 | .action_msg = "Terminate All Tasks", |
346 | .enable_mask = SYSRQ_ENABLE_SIGNAL, | |
347 | }; | |
348 | ||
65f27f38 | 349 | static void moom_callback(struct work_struct *ignored) |
1da177e4 | 350 | { |
53186095 DR |
351 | out_of_memory(node_zonelist(first_online_node, GFP_KERNEL), GFP_KERNEL, |
352 | 0, NULL, true); | |
1da177e4 LT |
353 | } |
354 | ||
65f27f38 | 355 | static DECLARE_WORK(moom_work, moom_callback); |
1da177e4 | 356 | |
1495cc9d | 357 | static void sysrq_handle_moom(int key) |
1da177e4 LT |
358 | { |
359 | schedule_work(&moom_work); | |
360 | } | |
361 | static struct sysrq_key_op sysrq_moom_op = { | |
362 | .handler = sysrq_handle_moom, | |
208b95ce | 363 | .help_msg = "memory-full-oom-kill(F)", |
1da177e4 | 364 | .action_msg = "Manual OOM execution", |
b4236f81 | 365 | .enable_mask = SYSRQ_ENABLE_SIGNAL, |
1da177e4 LT |
366 | }; |
367 | ||
c2d75438 | 368 | #ifdef CONFIG_BLOCK |
1495cc9d | 369 | static void sysrq_handle_thaw(int key) |
c2d75438 ES |
370 | { |
371 | emergency_thaw_all(); | |
372 | } | |
373 | static struct sysrq_key_op sysrq_thaw_op = { | |
374 | .handler = sysrq_handle_thaw, | |
375 | .help_msg = "thaw-filesystems(J)", | |
376 | .action_msg = "Emergency Thaw of all frozen filesystems", | |
377 | .enable_mask = SYSRQ_ENABLE_SIGNAL, | |
378 | }; | |
379 | #endif | |
380 | ||
1495cc9d | 381 | static void sysrq_handle_kill(int key) |
1da177e4 LT |
382 | { |
383 | send_sig_all(SIGKILL); | |
384 | console_loglevel = 8; | |
385 | } | |
386 | static struct sysrq_key_op sysrq_kill_op = { | |
387 | .handler = sysrq_handle_kill, | |
208b95ce | 388 | .help_msg = "kill-all-tasks(I)", |
1da177e4 LT |
389 | .action_msg = "Kill All Tasks", |
390 | .enable_mask = SYSRQ_ENABLE_SIGNAL, | |
391 | }; | |
392 | ||
1495cc9d | 393 | static void sysrq_handle_unrt(int key) |
1da177e4 LT |
394 | { |
395 | normalize_rt_tasks(); | |
396 | } | |
397 | static struct sysrq_key_op sysrq_unrt_op = { | |
398 | .handler = sysrq_handle_unrt, | |
208b95ce | 399 | .help_msg = "nice-all-RT-tasks(N)", |
1da177e4 LT |
400 | .action_msg = "Nice All RT Tasks", |
401 | .enable_mask = SYSRQ_ENABLE_RTNICE, | |
402 | }; | |
403 | ||
404 | /* Key Operations table and lock */ | |
405 | static DEFINE_SPINLOCK(sysrq_key_table_lock); | |
bf36b901 AM |
406 | |
407 | static struct sysrq_key_op *sysrq_key_table[36] = { | |
408 | &sysrq_loglevel_op, /* 0 */ | |
409 | &sysrq_loglevel_op, /* 1 */ | |
410 | &sysrq_loglevel_op, /* 2 */ | |
411 | &sysrq_loglevel_op, /* 3 */ | |
412 | &sysrq_loglevel_op, /* 4 */ | |
413 | &sysrq_loglevel_op, /* 5 */ | |
414 | &sysrq_loglevel_op, /* 6 */ | |
415 | &sysrq_loglevel_op, /* 7 */ | |
416 | &sysrq_loglevel_op, /* 8 */ | |
417 | &sysrq_loglevel_op, /* 9 */ | |
418 | ||
419 | /* | |
d346cce3 RD |
420 | * a: Don't use for system provided sysrqs, it is handled specially on |
421 | * sparc and will never arrive. | |
bf36b901 AM |
422 | */ |
423 | NULL, /* a */ | |
424 | &sysrq_reboot_op, /* b */ | |
cab8bd34 | 425 | &sysrq_crash_op, /* c & ibm_emac driver debug */ |
bf36b901 AM |
426 | &sysrq_showlocks_op, /* d */ |
427 | &sysrq_term_op, /* e */ | |
428 | &sysrq_moom_op, /* f */ | |
364b5b7b | 429 | /* g: May be registered for the kernel debugger */ |
bf36b901 | 430 | NULL, /* g */ |
c2d75438 | 431 | NULL, /* h - reserved for help */ |
bf36b901 | 432 | &sysrq_kill_op, /* i */ |
c2d75438 ES |
433 | #ifdef CONFIG_BLOCK |
434 | &sysrq_thaw_op, /* j */ | |
435 | #else | |
bf36b901 | 436 | NULL, /* j */ |
c2d75438 | 437 | #endif |
bf36b901 | 438 | &sysrq_SAK_op, /* k */ |
5045bcae RR |
439 | #ifdef CONFIG_SMP |
440 | &sysrq_showallcpus_op, /* l */ | |
441 | #else | |
bf36b901 | 442 | NULL, /* l */ |
5045bcae | 443 | #endif |
bf36b901 AM |
444 | &sysrq_showmem_op, /* m */ |
445 | &sysrq_unrt_op, /* n */ | |
d346cce3 | 446 | /* o: This will often be registered as 'Off' at init time */ |
bf36b901 AM |
447 | NULL, /* o */ |
448 | &sysrq_showregs_op, /* p */ | |
88ad0bf6 | 449 | &sysrq_show_timers_op, /* q */ |
d346cce3 | 450 | &sysrq_unraw_op, /* r */ |
bf36b901 AM |
451 | &sysrq_sync_op, /* s */ |
452 | &sysrq_showstate_op, /* t */ | |
453 | &sysrq_mountro_op, /* u */ | |
364b5b7b | 454 | /* v: May be registered for frame buffer console restore */ |
bf36b901 | 455 | NULL, /* v */ |
d346cce3 RD |
456 | &sysrq_showstate_blocked_op, /* w */ |
457 | /* x: May be registered on ppc/powerpc for xmon */ | |
916ca14a | 458 | /* x: May be registered on sparc64 for global PMU dump */ |
d346cce3 | 459 | NULL, /* x */ |
93dae5b7 | 460 | /* y: May be registered on sparc64 for global register dump */ |
bf36b901 | 461 | NULL, /* y */ |
69f698ad | 462 | &sysrq_ftrace_dump_op, /* z */ |
1da177e4 LT |
463 | }; |
464 | ||
465 | /* key2index calculation, -1 on invalid index */ | |
bf36b901 AM |
466 | static int sysrq_key_table_key2index(int key) |
467 | { | |
1da177e4 | 468 | int retval; |
bf36b901 AM |
469 | |
470 | if ((key >= '0') && (key <= '9')) | |
1da177e4 | 471 | retval = key - '0'; |
bf36b901 | 472 | else if ((key >= 'a') && (key <= 'z')) |
1da177e4 | 473 | retval = key + 10 - 'a'; |
bf36b901 | 474 | else |
1da177e4 | 475 | retval = -1; |
1da177e4 LT |
476 | return retval; |
477 | } | |
478 | ||
479 | /* | |
480 | * get and put functions for the table, exposed to modules. | |
481 | */ | |
bf36b901 AM |
482 | struct sysrq_key_op *__sysrq_get_key_op(int key) |
483 | { | |
484 | struct sysrq_key_op *op_p = NULL; | |
1da177e4 | 485 | int i; |
bf36b901 | 486 | |
1da177e4 | 487 | i = sysrq_key_table_key2index(key); |
bf36b901 AM |
488 | if (i != -1) |
489 | op_p = sysrq_key_table[i]; | |
97f5f0cd | 490 | |
1da177e4 LT |
491 | return op_p; |
492 | } | |
493 | ||
bf36b901 AM |
494 | static void __sysrq_put_key_op(int key, struct sysrq_key_op *op_p) |
495 | { | |
496 | int i = sysrq_key_table_key2index(key); | |
1da177e4 | 497 | |
1da177e4 LT |
498 | if (i != -1) |
499 | sysrq_key_table[i] = op_p; | |
500 | } | |
501 | ||
f335397d | 502 | void __handle_sysrq(int key, bool check_mask) |
1da177e4 LT |
503 | { |
504 | struct sysrq_key_op *op_p; | |
505 | int orig_log_level; | |
bf36b901 | 506 | int i; |
1da177e4 LT |
507 | unsigned long flags; |
508 | ||
509 | spin_lock_irqsave(&sysrq_key_table_lock, flags); | |
fb144adc AW |
510 | /* |
511 | * Raise the apparent loglevel to maximum so that the sysrq header | |
512 | * is shown to provide the user with positive feedback. We do not | |
513 | * simply emit this at KERN_EMERG as that would change message | |
514 | * routing in the consumers of /proc/kmsg. | |
515 | */ | |
1da177e4 LT |
516 | orig_log_level = console_loglevel; |
517 | console_loglevel = 7; | |
518 | printk(KERN_INFO "SysRq : "); | |
519 | ||
520 | op_p = __sysrq_get_key_op(key); | |
521 | if (op_p) { | |
bf36b901 AM |
522 | /* |
523 | * Should we check for enabled operations (/proc/sysrq-trigger | |
524 | * should not) and is the invoked operation enabled? | |
525 | */ | |
5d6f647f | 526 | if (!check_mask || sysrq_on_mask(op_p->enable_mask)) { |
bf36b901 | 527 | printk("%s\n", op_p->action_msg); |
1da177e4 | 528 | console_loglevel = orig_log_level; |
1495cc9d | 529 | op_p->handler(key); |
bf36b901 | 530 | } else { |
1da177e4 | 531 | printk("This sysrq operation is disabled.\n"); |
bf36b901 | 532 | } |
1da177e4 LT |
533 | } else { |
534 | printk("HELP : "); | |
535 | /* Only print the help msg once per handler */ | |
bf36b901 AM |
536 | for (i = 0; i < ARRAY_SIZE(sysrq_key_table); i++) { |
537 | if (sysrq_key_table[i]) { | |
538 | int j; | |
539 | ||
540 | for (j = 0; sysrq_key_table[i] != | |
541 | sysrq_key_table[j]; j++) | |
542 | ; | |
543 | if (j != i) | |
544 | continue; | |
545 | printk("%s ", sysrq_key_table[i]->help_msg); | |
546 | } | |
1da177e4 | 547 | } |
bf36b901 | 548 | printk("\n"); |
1da177e4 LT |
549 | console_loglevel = orig_log_level; |
550 | } | |
551 | spin_unlock_irqrestore(&sysrq_key_table_lock, flags); | |
552 | } | |
553 | ||
f335397d | 554 | void handle_sysrq(int key) |
1da177e4 | 555 | { |
5d6f647f | 556 | if (sysrq_on()) |
f335397d | 557 | __handle_sysrq(key, true); |
1da177e4 | 558 | } |
bf36b901 | 559 | EXPORT_SYMBOL(handle_sysrq); |
1da177e4 | 560 | |
97f5f0cd DT |
561 | #ifdef CONFIG_INPUT |
562 | ||
563 | /* Simple translation table for the SysRq keys */ | |
fcb71930 | 564 | static const unsigned char sysrq_xlate[KEY_CNT] = |
97f5f0cd DT |
565 | "\000\0331234567890-=\177\t" /* 0x00 - 0x0f */ |
566 | "qwertyuiop[]\r\000as" /* 0x10 - 0x1f */ | |
567 | "dfghjkl;'`\000\\zxcv" /* 0x20 - 0x2f */ | |
568 | "bnm,./\000*\000 \000\201\202\203\204\205" /* 0x30 - 0x3f */ | |
569 | "\206\207\210\211\212\000\000789-456+1" /* 0x40 - 0x4f */ | |
570 | "230\177\000\000\213\214\000\000\000\000\000\000\000\000\000\000" /* 0x50 - 0x5f */ | |
571 | "\r\000/"; /* 0x60 - 0x6f */ | |
572 | ||
fcb71930 DT |
573 | struct sysrq_state { |
574 | struct input_handle handle; | |
575 | struct work_struct reinject_work; | |
576 | unsigned long key_down[BITS_TO_LONGS(KEY_CNT)]; | |
577 | unsigned int alt; | |
578 | unsigned int alt_use; | |
579 | bool active; | |
580 | bool need_reinject; | |
7ab7b5ad | 581 | bool reinjecting; |
154b7a48 MP |
582 | |
583 | /* reset sequence handling */ | |
584 | bool reset_canceled; | |
585 | unsigned long reset_keybit[BITS_TO_LONGS(KEY_CNT)]; | |
586 | int reset_seq_len; | |
587 | int reset_seq_cnt; | |
588 | int reset_seq_version; | |
fcb71930 DT |
589 | }; |
590 | ||
154b7a48 MP |
591 | #define SYSRQ_KEY_RESET_MAX 20 /* Should be plenty */ |
592 | static unsigned short sysrq_reset_seq[SYSRQ_KEY_RESET_MAX]; | |
593 | static unsigned int sysrq_reset_seq_len; | |
594 | static unsigned int sysrq_reset_seq_version = 1; | |
595 | ||
596 | static void sysrq_parse_reset_sequence(struct sysrq_state *state) | |
597 | { | |
598 | int i; | |
599 | unsigned short key; | |
600 | ||
601 | state->reset_seq_cnt = 0; | |
602 | ||
603 | for (i = 0; i < sysrq_reset_seq_len; i++) { | |
604 | key = sysrq_reset_seq[i]; | |
605 | ||
606 | if (key == KEY_RESERVED || key > KEY_MAX) | |
607 | break; | |
608 | ||
609 | __set_bit(key, state->reset_keybit); | |
610 | state->reset_seq_len++; | |
611 | ||
612 | if (test_bit(key, state->key_down)) | |
613 | state->reset_seq_cnt++; | |
614 | } | |
615 | ||
616 | /* Disable reset until old keys are not released */ | |
617 | state->reset_canceled = state->reset_seq_cnt != 0; | |
618 | ||
619 | state->reset_seq_version = sysrq_reset_seq_version; | |
620 | } | |
621 | ||
622 | static bool sysrq_detect_reset_sequence(struct sysrq_state *state, | |
623 | unsigned int code, int value) | |
624 | { | |
625 | if (!test_bit(code, state->reset_keybit)) { | |
626 | /* | |
627 | * Pressing any key _not_ in reset sequence cancels | |
628 | * the reset sequence. | |
629 | */ | |
630 | if (value && state->reset_seq_cnt) | |
631 | state->reset_canceled = true; | |
632 | } else if (value == 0) { | |
633 | /* key release */ | |
634 | if (--state->reset_seq_cnt == 0) | |
635 | state->reset_canceled = false; | |
636 | } else if (value == 1) { | |
637 | /* key press, not autorepeat */ | |
638 | if (++state->reset_seq_cnt == state->reset_seq_len && | |
639 | !state->reset_canceled) { | |
640 | return true; | |
641 | } | |
642 | } | |
643 | ||
644 | return false; | |
645 | } | |
646 | ||
fcb71930 DT |
647 | static void sysrq_reinject_alt_sysrq(struct work_struct *work) |
648 | { | |
649 | struct sysrq_state *sysrq = | |
650 | container_of(work, struct sysrq_state, reinject_work); | |
651 | struct input_handle *handle = &sysrq->handle; | |
652 | unsigned int alt_code = sysrq->alt_use; | |
653 | ||
654 | if (sysrq->need_reinject) { | |
7ab7b5ad DT |
655 | /* we do not want the assignment to be reordered */ |
656 | sysrq->reinjecting = true; | |
657 | mb(); | |
658 | ||
fcb71930 DT |
659 | /* Simulate press and release of Alt + SysRq */ |
660 | input_inject_event(handle, EV_KEY, alt_code, 1); | |
661 | input_inject_event(handle, EV_KEY, KEY_SYSRQ, 1); | |
662 | input_inject_event(handle, EV_SYN, SYN_REPORT, 1); | |
663 | ||
664 | input_inject_event(handle, EV_KEY, KEY_SYSRQ, 0); | |
665 | input_inject_event(handle, EV_KEY, alt_code, 0); | |
666 | input_inject_event(handle, EV_SYN, SYN_REPORT, 1); | |
7ab7b5ad DT |
667 | |
668 | mb(); | |
669 | sysrq->reinjecting = false; | |
fcb71930 DT |
670 | } |
671 | } | |
97f5f0cd | 672 | |
154b7a48 MP |
673 | static bool sysrq_handle_keypress(struct sysrq_state *sysrq, |
674 | unsigned int code, int value) | |
97f5f0cd | 675 | { |
fcb71930 | 676 | bool was_active = sysrq->active; |
1966cb22 DT |
677 | bool suppress; |
678 | ||
154b7a48 | 679 | switch (code) { |
7ab7b5ad | 680 | |
154b7a48 MP |
681 | case KEY_LEFTALT: |
682 | case KEY_RIGHTALT: | |
683 | if (!value) { | |
684 | /* One of ALTs is being released */ | |
685 | if (sysrq->active && code == sysrq->alt_use) | |
686 | sysrq->active = false; | |
1966cb22 | 687 | |
154b7a48 MP |
688 | sysrq->alt = KEY_RESERVED; |
689 | ||
690 | } else if (value != 2) { | |
691 | sysrq->alt = code; | |
692 | sysrq->need_reinject = false; | |
693 | } | |
fcb71930 | 694 | break; |
97f5f0cd | 695 | |
154b7a48 MP |
696 | case KEY_SYSRQ: |
697 | if (value == 1 && sysrq->alt != KEY_RESERVED) { | |
698 | sysrq->active = true; | |
699 | sysrq->alt_use = sysrq->alt; | |
700 | /* | |
701 | * If nothing else will be pressed we'll need | |
702 | * to re-inject Alt-SysRq keysroke. | |
703 | */ | |
704 | sysrq->need_reinject = true; | |
705 | } | |
97f5f0cd | 706 | |
154b7a48 MP |
707 | /* |
708 | * Pretend that sysrq was never pressed at all. This | |
709 | * is needed to properly handle KGDB which will try | |
710 | * to release all keys after exiting debugger. If we | |
711 | * do not clear key bit it KGDB will end up sending | |
712 | * release events for Alt and SysRq, potentially | |
713 | * triggering print screen function. | |
714 | */ | |
715 | if (sysrq->active) | |
716 | clear_bit(KEY_SYSRQ, sysrq->handle.dev->key); | |
f5dec511 | 717 | |
154b7a48 | 718 | break; |
fcb71930 | 719 | |
154b7a48 MP |
720 | default: |
721 | if (sysrq->active && value && value != 2) { | |
722 | sysrq->need_reinject = false; | |
723 | __handle_sysrq(sysrq_xlate[code], true); | |
724 | } | |
725 | break; | |
726 | } | |
fcb71930 | 727 | |
154b7a48 | 728 | suppress = sysrq->active; |
fcb71930 | 729 | |
154b7a48 | 730 | if (!sysrq->active) { |
fcb71930 | 731 | |
154b7a48 MP |
732 | /* |
733 | * See if reset sequence has changed since the last time. | |
734 | */ | |
735 | if (sysrq->reset_seq_version != sysrq_reset_seq_version) | |
736 | sysrq_parse_reset_sequence(sysrq); | |
fcb71930 | 737 | |
154b7a48 MP |
738 | /* |
739 | * If we are not suppressing key presses keep track of | |
740 | * keyboard state so we can release keys that have been | |
741 | * pressed before entering SysRq mode. | |
742 | */ | |
743 | if (value) | |
744 | set_bit(code, sysrq->key_down); | |
745 | else | |
746 | clear_bit(code, sysrq->key_down); | |
747 | ||
748 | if (was_active) | |
749 | schedule_work(&sysrq->reinject_work); | |
750 | ||
751 | if (sysrq_detect_reset_sequence(sysrq, code, value)) { | |
752 | /* Force emergency reboot */ | |
753 | __handle_sysrq(sysrq_xlate[KEY_B], false); | |
f5dec511 | 754 | } |
97f5f0cd | 755 | |
154b7a48 MP |
756 | } else if (value == 0 && test_and_clear_bit(code, sysrq->key_down)) { |
757 | /* | |
758 | * Pass on release events for keys that was pressed before | |
759 | * entering SysRq mode. | |
760 | */ | |
761 | suppress = false; | |
762 | } | |
fcb71930 | 763 | |
154b7a48 MP |
764 | return suppress; |
765 | } | |
fcb71930 | 766 | |
154b7a48 MP |
767 | static bool sysrq_filter(struct input_handle *handle, |
768 | unsigned int type, unsigned int code, int value) | |
769 | { | |
770 | struct sysrq_state *sysrq = handle->private; | |
771 | bool suppress; | |
fcb71930 | 772 | |
154b7a48 MP |
773 | /* |
774 | * Do not filter anything if we are in the process of re-injecting | |
775 | * Alt+SysRq combination. | |
776 | */ | |
777 | if (sysrq->reinjecting) | |
778 | return false; | |
779 | ||
780 | switch (type) { | |
781 | ||
782 | case EV_SYN: | |
783 | suppress = false; | |
784 | break; | |
785 | ||
786 | case EV_KEY: | |
787 | suppress = sysrq_handle_keypress(sysrq, code, value); | |
97f5f0cd DT |
788 | break; |
789 | ||
790 | default: | |
fcb71930 | 791 | suppress = sysrq->active; |
97f5f0cd DT |
792 | break; |
793 | } | |
794 | ||
1966cb22 | 795 | return suppress; |
97f5f0cd DT |
796 | } |
797 | ||
798 | static int sysrq_connect(struct input_handler *handler, | |
799 | struct input_dev *dev, | |
800 | const struct input_device_id *id) | |
801 | { | |
fcb71930 | 802 | struct sysrq_state *sysrq; |
97f5f0cd DT |
803 | int error; |
804 | ||
fcb71930 DT |
805 | sysrq = kzalloc(sizeof(struct sysrq_state), GFP_KERNEL); |
806 | if (!sysrq) | |
97f5f0cd DT |
807 | return -ENOMEM; |
808 | ||
fcb71930 DT |
809 | INIT_WORK(&sysrq->reinject_work, sysrq_reinject_alt_sysrq); |
810 | ||
811 | sysrq->handle.dev = dev; | |
812 | sysrq->handle.handler = handler; | |
813 | sysrq->handle.name = "sysrq"; | |
814 | sysrq->handle.private = sysrq; | |
97f5f0cd | 815 | |
fcb71930 | 816 | error = input_register_handle(&sysrq->handle); |
97f5f0cd DT |
817 | if (error) { |
818 | pr_err("Failed to register input sysrq handler, error %d\n", | |
819 | error); | |
820 | goto err_free; | |
821 | } | |
822 | ||
fcb71930 | 823 | error = input_open_device(&sysrq->handle); |
97f5f0cd DT |
824 | if (error) { |
825 | pr_err("Failed to open input device, error %d\n", error); | |
826 | goto err_unregister; | |
827 | } | |
828 | ||
829 | return 0; | |
830 | ||
831 | err_unregister: | |
fcb71930 | 832 | input_unregister_handle(&sysrq->handle); |
97f5f0cd | 833 | err_free: |
fcb71930 | 834 | kfree(sysrq); |
97f5f0cd DT |
835 | return error; |
836 | } | |
837 | ||
838 | static void sysrq_disconnect(struct input_handle *handle) | |
839 | { | |
fcb71930 DT |
840 | struct sysrq_state *sysrq = handle->private; |
841 | ||
97f5f0cd | 842 | input_close_device(handle); |
fcb71930 | 843 | cancel_work_sync(&sysrq->reinject_work); |
97f5f0cd | 844 | input_unregister_handle(handle); |
fcb71930 | 845 | kfree(sysrq); |
97f5f0cd DT |
846 | } |
847 | ||
848 | /* | |
1966cb22 DT |
849 | * We are matching on KEY_LEFTALT instead of KEY_SYSRQ because not all |
850 | * keyboards have SysRq key predefined and so user may add it to keymap | |
97f5f0cd DT |
851 | * later, but we expect all such keyboards to have left alt. |
852 | */ | |
853 | static const struct input_device_id sysrq_ids[] = { | |
854 | { | |
855 | .flags = INPUT_DEVICE_ID_MATCH_EVBIT | | |
856 | INPUT_DEVICE_ID_MATCH_KEYBIT, | |
857 | .evbit = { BIT_MASK(EV_KEY) }, | |
858 | .keybit = { BIT_MASK(KEY_LEFTALT) }, | |
859 | }, | |
860 | { }, | |
861 | }; | |
862 | ||
863 | static struct input_handler sysrq_handler = { | |
864 | .filter = sysrq_filter, | |
865 | .connect = sysrq_connect, | |
866 | .disconnect = sysrq_disconnect, | |
867 | .name = "sysrq", | |
868 | .id_table = sysrq_ids, | |
869 | }; | |
870 | ||
871 | static bool sysrq_handler_registered; | |
872 | ||
873 | static inline void sysrq_register_handler(void) | |
874 | { | |
154b7a48 MP |
875 | extern unsigned short platform_sysrq_reset_seq[] __weak; |
876 | unsigned short key; | |
97f5f0cd | 877 | int error; |
154b7a48 MP |
878 | int i; |
879 | ||
880 | if (platform_sysrq_reset_seq) { | |
881 | for (i = 0; i < ARRAY_SIZE(sysrq_reset_seq); i++) { | |
882 | key = platform_sysrq_reset_seq[i]; | |
883 | if (key == KEY_RESERVED || key > KEY_MAX) | |
884 | break; | |
885 | ||
886 | sysrq_reset_seq[sysrq_reset_seq_len++] = key; | |
887 | } | |
888 | } | |
97f5f0cd DT |
889 | |
890 | error = input_register_handler(&sysrq_handler); | |
891 | if (error) | |
892 | pr_err("Failed to register input handler, error %d", error); | |
893 | else | |
894 | sysrq_handler_registered = true; | |
895 | } | |
896 | ||
897 | static inline void sysrq_unregister_handler(void) | |
898 | { | |
899 | if (sysrq_handler_registered) { | |
900 | input_unregister_handler(&sysrq_handler); | |
901 | sysrq_handler_registered = false; | |
902 | } | |
903 | } | |
904 | ||
154b7a48 MP |
905 | static int sysrq_reset_seq_param_set(const char *buffer, |
906 | const struct kernel_param *kp) | |
907 | { | |
908 | unsigned long val; | |
909 | int error; | |
910 | ||
911 | error = strict_strtoul(buffer, 0, &val); | |
912 | if (error < 0) | |
913 | return error; | |
914 | ||
915 | if (val > KEY_MAX) | |
916 | return -EINVAL; | |
917 | ||
918 | *((unsigned short *)kp->arg) = val; | |
919 | sysrq_reset_seq_version++; | |
920 | ||
921 | return 0; | |
922 | } | |
923 | ||
924 | static struct kernel_param_ops param_ops_sysrq_reset_seq = { | |
925 | .get = param_get_ushort, | |
926 | .set = sysrq_reset_seq_param_set, | |
927 | }; | |
928 | ||
929 | #define param_check_sysrq_reset_seq(name, p) \ | |
930 | __param_check(name, p, unsigned short) | |
931 | ||
932 | module_param_array_named(reset_seq, sysrq_reset_seq, sysrq_reset_seq, | |
933 | &sysrq_reset_seq_len, 0644); | |
934 | ||
97f5f0cd DT |
935 | #else |
936 | ||
937 | static inline void sysrq_register_handler(void) | |
938 | { | |
939 | } | |
940 | ||
941 | static inline void sysrq_unregister_handler(void) | |
942 | { | |
943 | } | |
944 | ||
945 | #endif /* CONFIG_INPUT */ | |
946 | ||
947 | int sysrq_toggle_support(int enable_mask) | |
948 | { | |
949 | bool was_enabled = sysrq_on(); | |
950 | ||
951 | sysrq_enabled = enable_mask; | |
952 | ||
953 | if (was_enabled != sysrq_on()) { | |
954 | if (sysrq_on()) | |
955 | sysrq_register_handler(); | |
956 | else | |
957 | sysrq_unregister_handler(); | |
958 | } | |
959 | ||
960 | return 0; | |
961 | } | |
962 | ||
cf62ddce | 963 | static int __sysrq_swap_key_ops(int key, struct sysrq_key_op *insert_op_p, |
bf36b901 AM |
964 | struct sysrq_key_op *remove_op_p) |
965 | { | |
1da177e4 LT |
966 | int retval; |
967 | unsigned long flags; | |
968 | ||
969 | spin_lock_irqsave(&sysrq_key_table_lock, flags); | |
970 | if (__sysrq_get_key_op(key) == remove_op_p) { | |
971 | __sysrq_put_key_op(key, insert_op_p); | |
972 | retval = 0; | |
973 | } else { | |
974 | retval = -1; | |
975 | } | |
976 | spin_unlock_irqrestore(&sysrq_key_table_lock, flags); | |
1da177e4 LT |
977 | return retval; |
978 | } | |
979 | ||
980 | int register_sysrq_key(int key, struct sysrq_key_op *op_p) | |
981 | { | |
982 | return __sysrq_swap_key_ops(key, op_p, NULL); | |
983 | } | |
bf36b901 | 984 | EXPORT_SYMBOL(register_sysrq_key); |
1da177e4 LT |
985 | |
986 | int unregister_sysrq_key(int key, struct sysrq_key_op *op_p) | |
987 | { | |
988 | return __sysrq_swap_key_ops(key, NULL, op_p); | |
989 | } | |
1da177e4 | 990 | EXPORT_SYMBOL(unregister_sysrq_key); |
f40cbaa5 AD |
991 | |
992 | #ifdef CONFIG_PROC_FS | |
993 | /* | |
994 | * writing 'C' to /proc/sysrq-trigger is like sysrq-C | |
995 | */ | |
996 | static ssize_t write_sysrq_trigger(struct file *file, const char __user *buf, | |
997 | size_t count, loff_t *ppos) | |
998 | { | |
999 | if (count) { | |
1000 | char c; | |
1001 | ||
1002 | if (get_user(c, buf)) | |
1003 | return -EFAULT; | |
f335397d | 1004 | __handle_sysrq(c, false); |
f40cbaa5 | 1005 | } |
97f5f0cd | 1006 | |
f40cbaa5 AD |
1007 | return count; |
1008 | } | |
1009 | ||
1010 | static const struct file_operations proc_sysrq_trigger_operations = { | |
1011 | .write = write_sysrq_trigger, | |
6038f373 | 1012 | .llseek = noop_llseek, |
f40cbaa5 AD |
1013 | }; |
1014 | ||
97f5f0cd DT |
1015 | static void sysrq_init_procfs(void) |
1016 | { | |
1017 | if (!proc_create("sysrq-trigger", S_IWUSR, NULL, | |
1018 | &proc_sysrq_trigger_operations)) | |
1019 | pr_err("Failed to register proc interface\n"); | |
1020 | } | |
1021 | ||
1022 | #else | |
1023 | ||
1024 | static inline void sysrq_init_procfs(void) | |
1025 | { | |
1026 | } | |
1027 | ||
1028 | #endif /* CONFIG_PROC_FS */ | |
1029 | ||
f40cbaa5 AD |
1030 | static int __init sysrq_init(void) |
1031 | { | |
97f5f0cd DT |
1032 | sysrq_init_procfs(); |
1033 | ||
1034 | if (sysrq_on()) | |
1035 | sysrq_register_handler(); | |
1036 | ||
f40cbaa5 AD |
1037 | return 0; |
1038 | } | |
1039 | module_init(sysrq_init); |