net: Fix thinko in backport of skb destructor fix.
[linux-2.6/mini2440.git] / drivers / char / sysrq.c
blobd6a807f4077d0453c3825d01fb1b3403f513aece
1 /* -*- linux-c -*-
3 * $Id: sysrq.c,v 1.15 1998/08/23 14:56:41 mj Exp $
5 * Linux Magic System Request Key Hacks
7 * (c) 1997 Martin Mares <mj@atrey.karlin.mff.cuni.cz>
8 * based on ideas by Pavel Machek <pavel@atrey.karlin.mff.cuni.cz>
10 * (c) 2000 Crutcher Dunnavant <crutcher+kernel@datastacks.com>
11 * overhauled to use key registration
12 * based upon discusions in irc://irc.openprojects.net/#kernelnewbies
15 #include <linux/sched.h>
16 #include <linux/interrupt.h>
17 #include <linux/mm.h>
18 #include <linux/fs.h>
19 #include <linux/tty.h>
20 #include <linux/mount.h>
21 #include <linux/kdev_t.h>
22 #include <linux/major.h>
23 #include <linux/reboot.h>
24 #include <linux/sysrq.h>
25 #include <linux/kbd_kern.h>
26 #include <linux/proc_fs.h>
27 #include <linux/quotaops.h>
28 #include <linux/kernel.h>
29 #include <linux/module.h>
30 #include <linux/suspend.h>
31 #include <linux/writeback.h>
32 #include <linux/buffer_head.h> /* for fsync_bdev() */
33 #include <linux/swap.h>
34 #include <linux/spinlock.h>
35 #include <linux/vt_kern.h>
36 #include <linux/workqueue.h>
37 #include <linux/kexec.h>
38 #include <linux/hrtimer.h>
39 #include <linux/oom.h>
41 #include <asm/ptrace.h>
42 #include <asm/irq_regs.h>
44 /* Whether we react on sysrq keys or just ignore them */
45 int __read_mostly __sysrq_enabled = 1;
47 static int __read_mostly sysrq_always_enabled;
49 int sysrq_on(void)
51 return __sysrq_enabled || sysrq_always_enabled;
55 * A value of 1 means 'all', other nonzero values are an op mask:
57 static inline int sysrq_on_mask(int mask)
59 return sysrq_always_enabled || __sysrq_enabled == 1 ||
60 (__sysrq_enabled & mask);
63 static int __init sysrq_always_enabled_setup(char *str)
65 sysrq_always_enabled = 1;
66 printk(KERN_INFO "debug: sysrq always enabled.\n");
68 return 1;
71 __setup("sysrq_always_enabled", sysrq_always_enabled_setup);
74 static void sysrq_handle_loglevel(int key, struct tty_struct *tty)
76 int i;
77 i = key - '0';
78 console_loglevel = 7;
79 printk("Loglevel set to %d\n", i);
80 console_loglevel = i;
82 static struct sysrq_key_op sysrq_loglevel_op = {
83 .handler = sysrq_handle_loglevel,
84 .help_msg = "loglevel(0-9)",
85 .action_msg = "Changing Loglevel",
86 .enable_mask = SYSRQ_ENABLE_LOG,
89 #ifdef CONFIG_VT
90 static void sysrq_handle_SAK(int key, struct tty_struct *tty)
92 struct work_struct *SAK_work = &vc_cons[fg_console].SAK_work;
93 schedule_work(SAK_work);
95 static struct sysrq_key_op sysrq_SAK_op = {
96 .handler = sysrq_handle_SAK,
97 .help_msg = "saK",
98 .action_msg = "SAK",
99 .enable_mask = SYSRQ_ENABLE_KEYBOARD,
101 #else
102 #define sysrq_SAK_op (*(struct sysrq_key_op *)0)
103 #endif
105 #ifdef CONFIG_VT
106 static void sysrq_handle_unraw(int key, struct tty_struct *tty)
108 struct kbd_struct *kbd = &kbd_table[fg_console];
110 if (kbd)
111 kbd->kbdmode = default_utf8 ? VC_UNICODE : VC_XLATE;
113 static struct sysrq_key_op sysrq_unraw_op = {
114 .handler = sysrq_handle_unraw,
115 .help_msg = "unRaw",
116 .action_msg = "Keyboard mode set to system default",
117 .enable_mask = SYSRQ_ENABLE_KEYBOARD,
119 #else
120 #define sysrq_unraw_op (*(struct sysrq_key_op *)0)
121 #endif /* CONFIG_VT */
123 #ifdef CONFIG_KEXEC
124 static void sysrq_handle_crashdump(int key, struct tty_struct *tty)
126 crash_kexec(get_irq_regs());
128 static struct sysrq_key_op sysrq_crashdump_op = {
129 .handler = sysrq_handle_crashdump,
130 .help_msg = "Crashdump",
131 .action_msg = "Trigger a crashdump",
132 .enable_mask = SYSRQ_ENABLE_DUMP,
134 #else
135 #define sysrq_crashdump_op (*(struct sysrq_key_op *)0)
136 #endif
138 static void sysrq_handle_reboot(int key, struct tty_struct *tty)
140 lockdep_off();
141 local_irq_enable();
142 emergency_restart();
144 static struct sysrq_key_op sysrq_reboot_op = {
145 .handler = sysrq_handle_reboot,
146 .help_msg = "reBoot",
147 .action_msg = "Resetting",
148 .enable_mask = SYSRQ_ENABLE_BOOT,
151 static void sysrq_handle_sync(int key, struct tty_struct *tty)
153 emergency_sync();
155 static struct sysrq_key_op sysrq_sync_op = {
156 .handler = sysrq_handle_sync,
157 .help_msg = "Sync",
158 .action_msg = "Emergency Sync",
159 .enable_mask = SYSRQ_ENABLE_SYNC,
162 static void sysrq_handle_show_timers(int key, struct tty_struct *tty)
164 sysrq_timer_list_show();
167 static struct sysrq_key_op sysrq_show_timers_op = {
168 .handler = sysrq_handle_show_timers,
169 .help_msg = "show-all-timers(Q)",
170 .action_msg = "Show clockevent devices & pending hrtimers (no others)",
173 static void sysrq_handle_mountro(int key, struct tty_struct *tty)
175 emergency_remount();
177 static struct sysrq_key_op sysrq_mountro_op = {
178 .handler = sysrq_handle_mountro,
179 .help_msg = "Unmount",
180 .action_msg = "Emergency Remount R/O",
181 .enable_mask = SYSRQ_ENABLE_REMOUNT,
184 #ifdef CONFIG_LOCKDEP
185 static void sysrq_handle_showlocks(int key, struct tty_struct *tty)
187 debug_show_all_locks();
190 static struct sysrq_key_op sysrq_showlocks_op = {
191 .handler = sysrq_handle_showlocks,
192 .help_msg = "show-all-locks(D)",
193 .action_msg = "Show Locks Held",
195 #else
196 #define sysrq_showlocks_op (*(struct sysrq_key_op *)0)
197 #endif
199 #ifdef CONFIG_SMP
200 static DEFINE_SPINLOCK(show_lock);
202 static void showacpu(void *dummy)
204 unsigned long flags;
206 /* Idle CPUs have no interesting backtrace. */
207 if (idle_cpu(smp_processor_id()))
208 return;
210 spin_lock_irqsave(&show_lock, flags);
211 printk(KERN_INFO "CPU%d:\n", smp_processor_id());
212 show_stack(NULL, NULL);
213 spin_unlock_irqrestore(&show_lock, flags);
216 static void sysrq_showregs_othercpus(struct work_struct *dummy)
218 smp_call_function(showacpu, NULL, 0);
221 static DECLARE_WORK(sysrq_showallcpus, sysrq_showregs_othercpus);
223 static void sysrq_handle_showallcpus(int key, struct tty_struct *tty)
225 struct pt_regs *regs = get_irq_regs();
226 if (regs) {
227 printk(KERN_INFO "CPU%d:\n", smp_processor_id());
228 show_regs(regs);
230 schedule_work(&sysrq_showallcpus);
233 static struct sysrq_key_op sysrq_showallcpus_op = {
234 .handler = sysrq_handle_showallcpus,
235 .help_msg = "show-backtrace-all-active-cpus(L)",
236 .action_msg = "Show backtrace of all active CPUs",
237 .enable_mask = SYSRQ_ENABLE_DUMP,
239 #endif
241 static void sysrq_handle_showregs(int key, struct tty_struct *tty)
243 struct pt_regs *regs = get_irq_regs();
244 if (regs)
245 show_regs(regs);
247 static struct sysrq_key_op sysrq_showregs_op = {
248 .handler = sysrq_handle_showregs,
249 .help_msg = "show-registers(P)",
250 .action_msg = "Show Regs",
251 .enable_mask = SYSRQ_ENABLE_DUMP,
254 static void sysrq_handle_showstate(int key, struct tty_struct *tty)
256 show_state();
258 static struct sysrq_key_op sysrq_showstate_op = {
259 .handler = sysrq_handle_showstate,
260 .help_msg = "show-task-states(T)",
261 .action_msg = "Show State",
262 .enable_mask = SYSRQ_ENABLE_DUMP,
265 static void sysrq_handle_showstate_blocked(int key, struct tty_struct *tty)
267 show_state_filter(TASK_UNINTERRUPTIBLE);
269 static struct sysrq_key_op sysrq_showstate_blocked_op = {
270 .handler = sysrq_handle_showstate_blocked,
271 .help_msg = "show-blocked-tasks(W)",
272 .action_msg = "Show Blocked State",
273 .enable_mask = SYSRQ_ENABLE_DUMP,
276 #ifdef CONFIG_TRACING
277 #include <linux/ftrace.h>
279 static void sysrq_ftrace_dump(int key, struct tty_struct *tty)
281 ftrace_dump();
283 static struct sysrq_key_op sysrq_ftrace_dump_op = {
284 .handler = sysrq_ftrace_dump,
285 .help_msg = "dump-ftrace-buffer(Z)",
286 .action_msg = "Dump ftrace buffer",
287 .enable_mask = SYSRQ_ENABLE_DUMP,
289 #else
290 #define sysrq_ftrace_dump_op (*(struct sysrq_key_op *)0)
291 #endif
293 static void sysrq_handle_showmem(int key, struct tty_struct *tty)
295 show_mem();
297 static struct sysrq_key_op sysrq_showmem_op = {
298 .handler = sysrq_handle_showmem,
299 .help_msg = "show-memory-usage(M)",
300 .action_msg = "Show Memory",
301 .enable_mask = SYSRQ_ENABLE_DUMP,
305 * Signal sysrq helper function. Sends a signal to all user processes.
307 static void send_sig_all(int sig)
309 struct task_struct *p;
311 for_each_process(p) {
312 if (p->mm && !is_global_init(p))
313 /* Not swapper, init nor kernel thread */
314 force_sig(sig, p);
318 static void sysrq_handle_term(int key, struct tty_struct *tty)
320 send_sig_all(SIGTERM);
321 console_loglevel = 8;
323 static struct sysrq_key_op sysrq_term_op = {
324 .handler = sysrq_handle_term,
325 .help_msg = "terminate-all-tasks(E)",
326 .action_msg = "Terminate All Tasks",
327 .enable_mask = SYSRQ_ENABLE_SIGNAL,
330 static void moom_callback(struct work_struct *ignored)
332 out_of_memory(node_zonelist(0, GFP_KERNEL), GFP_KERNEL, 0);
335 static DECLARE_WORK(moom_work, moom_callback);
337 static void sysrq_handle_moom(int key, struct tty_struct *tty)
339 schedule_work(&moom_work);
341 static struct sysrq_key_op sysrq_moom_op = {
342 .handler = sysrq_handle_moom,
343 .help_msg = "memory-full-oom-kill(F)",
344 .action_msg = "Manual OOM execution",
345 .enable_mask = SYSRQ_ENABLE_SIGNAL,
348 #ifdef CONFIG_BLOCK
349 static void sysrq_handle_thaw(int key, struct tty_struct *tty)
351 emergency_thaw_all();
353 static struct sysrq_key_op sysrq_thaw_op = {
354 .handler = sysrq_handle_thaw,
355 .help_msg = "thaw-filesystems(J)",
356 .action_msg = "Emergency Thaw of all frozen filesystems",
357 .enable_mask = SYSRQ_ENABLE_SIGNAL,
359 #endif
361 static void sysrq_handle_kill(int key, struct tty_struct *tty)
363 send_sig_all(SIGKILL);
364 console_loglevel = 8;
366 static struct sysrq_key_op sysrq_kill_op = {
367 .handler = sysrq_handle_kill,
368 .help_msg = "kill-all-tasks(I)",
369 .action_msg = "Kill All Tasks",
370 .enable_mask = SYSRQ_ENABLE_SIGNAL,
373 static void sysrq_handle_unrt(int key, struct tty_struct *tty)
375 normalize_rt_tasks();
377 static struct sysrq_key_op sysrq_unrt_op = {
378 .handler = sysrq_handle_unrt,
379 .help_msg = "nice-all-RT-tasks(N)",
380 .action_msg = "Nice All RT Tasks",
381 .enable_mask = SYSRQ_ENABLE_RTNICE,
384 /* Key Operations table and lock */
385 static DEFINE_SPINLOCK(sysrq_key_table_lock);
387 static struct sysrq_key_op *sysrq_key_table[36] = {
388 &sysrq_loglevel_op, /* 0 */
389 &sysrq_loglevel_op, /* 1 */
390 &sysrq_loglevel_op, /* 2 */
391 &sysrq_loglevel_op, /* 3 */
392 &sysrq_loglevel_op, /* 4 */
393 &sysrq_loglevel_op, /* 5 */
394 &sysrq_loglevel_op, /* 6 */
395 &sysrq_loglevel_op, /* 7 */
396 &sysrq_loglevel_op, /* 8 */
397 &sysrq_loglevel_op, /* 9 */
400 * a: Don't use for system provided sysrqs, it is handled specially on
401 * sparc and will never arrive.
403 NULL, /* a */
404 &sysrq_reboot_op, /* b */
405 &sysrq_crashdump_op, /* c & ibm_emac driver debug */
406 &sysrq_showlocks_op, /* d */
407 &sysrq_term_op, /* e */
408 &sysrq_moom_op, /* f */
409 /* g: May be registered for the kernel debugger */
410 NULL, /* g */
411 NULL, /* h - reserved for help */
412 &sysrq_kill_op, /* i */
413 #ifdef CONFIG_BLOCK
414 &sysrq_thaw_op, /* j */
415 #else
416 NULL, /* j */
417 #endif
418 &sysrq_SAK_op, /* k */
419 #ifdef CONFIG_SMP
420 &sysrq_showallcpus_op, /* l */
421 #else
422 NULL, /* l */
423 #endif
424 &sysrq_showmem_op, /* m */
425 &sysrq_unrt_op, /* n */
426 /* o: This will often be registered as 'Off' at init time */
427 NULL, /* o */
428 &sysrq_showregs_op, /* p */
429 &sysrq_show_timers_op, /* q */
430 &sysrq_unraw_op, /* r */
431 &sysrq_sync_op, /* s */
432 &sysrq_showstate_op, /* t */
433 &sysrq_mountro_op, /* u */
434 /* v: May be registered for frame buffer console restore */
435 NULL, /* v */
436 &sysrq_showstate_blocked_op, /* w */
437 /* x: May be registered on ppc/powerpc for xmon */
438 NULL, /* x */
439 /* y: May be registered on sparc64 for global register dump */
440 NULL, /* y */
441 &sysrq_ftrace_dump_op, /* z */
444 /* key2index calculation, -1 on invalid index */
445 static int sysrq_key_table_key2index(int key)
447 int retval;
449 if ((key >= '0') && (key <= '9'))
450 retval = key - '0';
451 else if ((key >= 'a') && (key <= 'z'))
452 retval = key + 10 - 'a';
453 else
454 retval = -1;
455 return retval;
459 * get and put functions for the table, exposed to modules.
461 struct sysrq_key_op *__sysrq_get_key_op(int key)
463 struct sysrq_key_op *op_p = NULL;
464 int i;
466 i = sysrq_key_table_key2index(key);
467 if (i != -1)
468 op_p = sysrq_key_table[i];
469 return op_p;
472 static void __sysrq_put_key_op(int key, struct sysrq_key_op *op_p)
474 int i = sysrq_key_table_key2index(key);
476 if (i != -1)
477 sysrq_key_table[i] = op_p;
481 * This is the non-locking version of handle_sysrq. It must/can only be called
482 * by sysrq key handlers, as they are inside of the lock
484 void __handle_sysrq(int key, struct tty_struct *tty, int check_mask)
486 struct sysrq_key_op *op_p;
487 int orig_log_level;
488 int i;
489 unsigned long flags;
491 spin_lock_irqsave(&sysrq_key_table_lock, flags);
493 * Raise the apparent loglevel to maximum so that the sysrq header
494 * is shown to provide the user with positive feedback. We do not
495 * simply emit this at KERN_EMERG as that would change message
496 * routing in the consumers of /proc/kmsg.
498 orig_log_level = console_loglevel;
499 console_loglevel = 7;
500 printk(KERN_INFO "SysRq : ");
502 op_p = __sysrq_get_key_op(key);
503 if (op_p) {
505 * Should we check for enabled operations (/proc/sysrq-trigger
506 * should not) and is the invoked operation enabled?
508 if (!check_mask || sysrq_on_mask(op_p->enable_mask)) {
509 printk("%s\n", op_p->action_msg);
510 console_loglevel = orig_log_level;
511 op_p->handler(key, tty);
512 } else {
513 printk("This sysrq operation is disabled.\n");
515 } else {
516 printk("HELP : ");
517 /* Only print the help msg once per handler */
518 for (i = 0; i < ARRAY_SIZE(sysrq_key_table); i++) {
519 if (sysrq_key_table[i]) {
520 int j;
522 for (j = 0; sysrq_key_table[i] !=
523 sysrq_key_table[j]; j++)
525 if (j != i)
526 continue;
527 printk("%s ", sysrq_key_table[i]->help_msg);
530 printk("\n");
531 console_loglevel = orig_log_level;
533 spin_unlock_irqrestore(&sysrq_key_table_lock, flags);
537 * This function is called by the keyboard handler when SysRq is pressed
538 * and any other keycode arrives.
540 void handle_sysrq(int key, struct tty_struct *tty)
542 if (sysrq_on())
543 __handle_sysrq(key, tty, 1);
545 EXPORT_SYMBOL(handle_sysrq);
547 static int __sysrq_swap_key_ops(int key, struct sysrq_key_op *insert_op_p,
548 struct sysrq_key_op *remove_op_p)
551 int retval;
552 unsigned long flags;
554 spin_lock_irqsave(&sysrq_key_table_lock, flags);
555 if (__sysrq_get_key_op(key) == remove_op_p) {
556 __sysrq_put_key_op(key, insert_op_p);
557 retval = 0;
558 } else {
559 retval = -1;
561 spin_unlock_irqrestore(&sysrq_key_table_lock, flags);
562 return retval;
565 int register_sysrq_key(int key, struct sysrq_key_op *op_p)
567 return __sysrq_swap_key_ops(key, op_p, NULL);
569 EXPORT_SYMBOL(register_sysrq_key);
571 int unregister_sysrq_key(int key, struct sysrq_key_op *op_p)
573 return __sysrq_swap_key_ops(key, NULL, op_p);
575 EXPORT_SYMBOL(unregister_sysrq_key);
577 #ifdef CONFIG_PROC_FS
579 * writing 'C' to /proc/sysrq-trigger is like sysrq-C
581 static ssize_t write_sysrq_trigger(struct file *file, const char __user *buf,
582 size_t count, loff_t *ppos)
584 if (count) {
585 char c;
587 if (get_user(c, buf))
588 return -EFAULT;
589 __handle_sysrq(c, NULL, 0);
591 return count;
594 static const struct file_operations proc_sysrq_trigger_operations = {
595 .write = write_sysrq_trigger,
598 static int __init sysrq_init(void)
600 proc_create("sysrq-trigger", S_IWUSR, NULL, &proc_sysrq_trigger_operations);
601 return 0;
603 module_init(sysrq_init);
604 #endif