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/config.h>
16 #include <linux/sched.h>
17 #include <linux/interrupt.h>
20 #include <linux/tty.h>
21 #include <linux/mount.h>
22 #include <linux/kdev_t.h>
23 #include <linux/major.h>
24 #include <linux/reboot.h>
25 #include <linux/sysrq.h>
26 #include <linux/kbd_kern.h>
27 #include <linux/quotaops.h>
28 #include <linux/smp_lock.h>
29 #include <linux/kernel.h>
30 #include <linux/module.h>
31 #include <linux/suspend.h>
32 #include <linux/writeback.h>
33 #include <linux/buffer_head.h> /* for fsync_bdev() */
35 #include <linux/spinlock.h>
37 #include <asm/ptrace.h>
39 extern void reset_vc(unsigned int);
41 /* Whether we react on sysrq keys or just ignore them */
42 int sysrq_enabled = 1;
44 /* Machine specific power off function */
45 void (*sysrq_power_off)(void);
47 /* Loglevel sysrq handler */
48 static void sysrq_handle_loglevel(int key, struct pt_regs *pt_regs,
49 struct tty_struct *tty)
54 printk("Loglevel set to %d\n", i);
57 static struct sysrq_key_op sysrq_loglevel_op = {
58 .handler = sysrq_handle_loglevel,
59 .help_msg = "loglevel0-8",
60 .action_msg = "Changing Loglevel",
64 /* SAK sysrq handler */
66 static void sysrq_handle_SAK(int key, struct pt_regs *pt_regs,
67 struct tty_struct *tty)
73 static struct sysrq_key_op sysrq_SAK_op = {
74 .handler = sysrq_handle_SAK,
81 /* unraw sysrq handler */
82 static void sysrq_handle_unraw(int key, struct pt_regs *pt_regs,
83 struct tty_struct *tty)
85 struct kbd_struct *kbd = &kbd_table[fg_console];
88 kbd->kbdmode = VC_XLATE;
90 static struct sysrq_key_op sysrq_unraw_op = {
91 .handler = sysrq_handle_unraw,
93 .action_msg = "Keyboard mode set to XLATE",
95 #endif /* CONFIG_VT */
97 /* reboot sysrq handler */
98 static void sysrq_handle_reboot(int key, struct pt_regs *pt_regs,
99 struct tty_struct *tty)
102 machine_restart(NULL);
105 static struct sysrq_key_op sysrq_reboot_op = {
106 .handler = sysrq_handle_reboot,
107 .help_msg = "reBoot",
108 .action_msg = "Resetting",
111 static void sysrq_handle_sync(int key, struct pt_regs *pt_regs,
112 struct tty_struct *tty)
117 static struct sysrq_key_op sysrq_sync_op = {
118 .handler = sysrq_handle_sync,
120 .action_msg = "Emergency Sync",
123 static void sysrq_handle_mountro(int key, struct pt_regs *pt_regs,
124 struct tty_struct *tty)
129 static struct sysrq_key_op sysrq_mountro_op = {
130 .handler = sysrq_handle_mountro,
131 .help_msg = "Unmount",
132 .action_msg = "Emergency Remount R/O",
135 /* END SYNC SYSRQ HANDLERS BLOCK */
138 /* SHOW SYSRQ HANDLERS BLOCK */
140 static void sysrq_handle_showregs(int key, struct pt_regs *pt_regs,
141 struct tty_struct *tty)
146 static struct sysrq_key_op sysrq_showregs_op = {
147 .handler = sysrq_handle_showregs,
148 .help_msg = "showPc",
149 .action_msg = "Show Regs",
153 static void sysrq_handle_showstate(int key, struct pt_regs *pt_regs,
154 struct tty_struct *tty)
158 static struct sysrq_key_op sysrq_showstate_op = {
159 .handler = sysrq_handle_showstate,
160 .help_msg = "showTasks",
161 .action_msg = "Show State",
165 static void sysrq_handle_showmem(int key, struct pt_regs *pt_regs,
166 struct tty_struct *tty)
170 static struct sysrq_key_op sysrq_showmem_op = {
171 .handler = sysrq_handle_showmem,
172 .help_msg = "showMem",
173 .action_msg = "Show Memory",
176 /* SHOW SYSRQ HANDLERS BLOCK */
179 /* SIGNAL SYSRQ HANDLERS BLOCK */
181 /* signal sysrq helper function
182 * Sends a signal to all user processes */
183 static void send_sig_all(int sig)
185 struct task_struct *p;
187 for_each_process(p) {
188 if (p->mm && p->pid != 1)
189 /* Not swapper, init nor kernel thread */
194 static void sysrq_handle_term(int key, struct pt_regs *pt_regs,
195 struct tty_struct *tty)
197 send_sig_all(SIGTERM);
198 console_loglevel = 8;
200 static struct sysrq_key_op sysrq_term_op = {
201 .handler = sysrq_handle_term,
203 .action_msg = "Terminate All Tasks",
206 static void sysrq_handle_kill(int key, struct pt_regs *pt_regs,
207 struct tty_struct *tty)
209 send_sig_all(SIGKILL);
210 console_loglevel = 8;
212 static struct sysrq_key_op sysrq_kill_op = {
213 .handler = sysrq_handle_kill,
215 .action_msg = "Kill All Tasks",
218 /* END SIGNAL SYSRQ HANDLERS BLOCK */
220 static void sysrq_handle_unrt(int key, struct pt_regs *pt_regs,
221 struct tty_struct *tty)
223 normalize_rt_tasks();
225 static struct sysrq_key_op sysrq_unrt_op = {
226 .handler = sysrq_handle_unrt,
228 .action_msg = "Nice All RT Tasks"
231 /* Key Operations table and lock */
232 static DEFINE_SPINLOCK(sysrq_key_table_lock);
233 #define SYSRQ_KEY_TABLE_LENGTH 36
234 static struct sysrq_key_op *sysrq_key_table[SYSRQ_KEY_TABLE_LENGTH] = {
235 /* 0 */ &sysrq_loglevel_op,
236 /* 1 */ &sysrq_loglevel_op,
237 /* 2 */ &sysrq_loglevel_op,
238 /* 3 */ &sysrq_loglevel_op,
239 /* 4 */ &sysrq_loglevel_op,
240 /* 5 */ &sysrq_loglevel_op,
241 /* 6 */ &sysrq_loglevel_op,
242 /* 7 */ &sysrq_loglevel_op,
243 /* 8 */ &sysrq_loglevel_op,
244 /* 9 */ &sysrq_loglevel_op,
245 /* a */ NULL, /* Don't use for system provided sysrqs,
246 it is handled specially on the sparc
247 and will never arrive */
248 /* b */ &sysrq_reboot_op,
251 /* e */ &sysrq_term_op,
255 /* i */ &sysrq_kill_op,
258 /* k */ &sysrq_SAK_op,
263 /* m */ &sysrq_showmem_op,
264 /* n */ &sysrq_unrt_op,
265 /* o */ NULL, /* This will often be registered
266 as 'Off' at init time */
267 /* p */ &sysrq_showregs_op,
270 /* r */ &sysrq_unraw_op,
274 /* s */ &sysrq_sync_op,
275 /* t */ &sysrq_showstate_op,
276 /* u */ &sysrq_mountro_op,
277 /* v */ NULL, /* May be assigned at init time by SMP VOYAGER */
284 /* key2index calculation, -1 on invalid index */
285 static int sysrq_key_table_key2index(int key) {
287 if ((key >= '0') && (key <= '9')) {
289 } else if ((key >= 'a') && (key <= 'z')) {
290 retval = key + 10 - 'a';
298 * get and put functions for the table, exposed to modules.
301 struct sysrq_key_op *__sysrq_get_key_op (int key) {
302 struct sysrq_key_op *op_p;
305 i = sysrq_key_table_key2index(key);
306 op_p = (i == -1) ? NULL : sysrq_key_table[i];
310 void __sysrq_put_key_op (int key, struct sysrq_key_op *op_p) {
313 i = sysrq_key_table_key2index(key);
315 sysrq_key_table[i] = op_p;
319 * This is the non-locking version of handle_sysrq
320 * It must/can only be called by sysrq key handlers,
321 * as they are inside of the lock
324 void __handle_sysrq(int key, struct pt_regs *pt_regs, struct tty_struct *tty)
326 struct sysrq_key_op *op_p;
331 spin_lock_irqsave(&sysrq_key_table_lock, flags);
332 orig_log_level = console_loglevel;
333 console_loglevel = 7;
334 printk(KERN_INFO "SysRq : ");
336 op_p = __sysrq_get_key_op(key);
338 printk ("%s\n", op_p->action_msg);
339 console_loglevel = orig_log_level;
340 op_p->handler(key, pt_regs, tty);
343 /* Only print the help msg once per handler */
344 for (i=0; i<SYSRQ_KEY_TABLE_LENGTH; i++)
345 if (sysrq_key_table[i]) {
346 for (j=0; sysrq_key_table[i] != sysrq_key_table[j]; j++);
348 printk ("%s ", sysrq_key_table[i]->help_msg);
351 console_loglevel = orig_log_level;
353 spin_unlock_irqrestore(&sysrq_key_table_lock, flags);
357 * This function is called by the keyboard handler when SysRq is pressed
358 * and any other keycode arrives.
361 void handle_sysrq(int key, struct pt_regs *pt_regs, struct tty_struct *tty)
365 __handle_sysrq(key, pt_regs, tty);
368 int __sysrq_swap_key_ops(int key, struct sysrq_key_op *insert_op_p,
369 struct sysrq_key_op *remove_op_p) {
374 spin_lock_irqsave(&sysrq_key_table_lock, flags);
375 if (__sysrq_get_key_op(key) == remove_op_p) {
376 __sysrq_put_key_op(key, insert_op_p);
381 spin_unlock_irqrestore(&sysrq_key_table_lock, flags);
386 int register_sysrq_key(int key, struct sysrq_key_op *op_p)
388 return __sysrq_swap_key_ops(key, op_p, NULL);
391 int unregister_sysrq_key(int key, struct sysrq_key_op *op_p)
393 return __sysrq_swap_key_ops(key, NULL, op_p);
396 EXPORT_SYMBOL(handle_sysrq);
397 EXPORT_SYMBOL(register_sysrq_key);
398 EXPORT_SYMBOL(unregister_sysrq_key);