ia64/linux-2.6.18-xen.hg

view drivers/char/sysrq.c @ 893:f994bfe9b93b

linux/blktap2: reduce TLB flush scope

c/s 885 added very coarse TLB flushing. Since these flushes always
follow single page updates, single page flushes (when available) are
sufficient.

Signed-off-by: Jan Beulich <jbeulich@novell.com>
author Keir Fraser <keir.fraser@citrix.com>
date Thu Jun 04 10:32:57 2009 +0100 (2009-06-04)
parents 831230e53067
children
line source
1 /* -*- linux-c -*-
2 *
3 * $Id: sysrq.c,v 1.15 1998/08/23 14:56:41 mj Exp $
4 *
5 * Linux Magic System Request Key Hacks
6 *
7 * (c) 1997 Martin Mares <mj@atrey.karlin.mff.cuni.cz>
8 * based on ideas by Pavel Machek <pavel@atrey.karlin.mff.cuni.cz>
9 *
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
13 */
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/quotaops.h>
27 #include <linux/smp_lock.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>
39 #include <asm/ptrace.h>
41 /* Whether we react on sysrq keys or just ignore them */
42 int sysrq_enabled = 1;
44 static void sysrq_handle_loglevel(int key, struct pt_regs *pt_regs,
45 struct tty_struct *tty)
46 {
47 int i;
48 i = key - '0';
49 console_loglevel = 7;
50 printk("Loglevel set to %d\n", i);
51 console_loglevel = i;
52 }
53 static struct sysrq_key_op sysrq_loglevel_op = {
54 .handler = sysrq_handle_loglevel,
55 .help_msg = "loglevel0-8",
56 .action_msg = "Changing Loglevel",
57 .enable_mask = SYSRQ_ENABLE_LOG,
58 };
60 #ifdef CONFIG_VT
61 static void sysrq_handle_SAK(int key, struct pt_regs *pt_regs,
62 struct tty_struct *tty)
63 {
64 if (tty)
65 do_SAK(tty);
66 reset_vc(vc_cons[fg_console].d);
67 }
68 static struct sysrq_key_op sysrq_SAK_op = {
69 .handler = sysrq_handle_SAK,
70 .help_msg = "saK",
71 .action_msg = "SAK",
72 .enable_mask = SYSRQ_ENABLE_KEYBOARD,
73 };
74 #else
75 #define sysrq_SAK_op (*(struct sysrq_key_op *)0)
76 #endif
78 #ifdef CONFIG_VT
79 static void sysrq_handle_unraw(int key, struct pt_regs *pt_regs,
80 struct tty_struct *tty)
81 {
82 struct kbd_struct *kbd = &kbd_table[fg_console];
84 if (kbd)
85 kbd->kbdmode = VC_XLATE;
86 }
87 static struct sysrq_key_op sysrq_unraw_op = {
88 .handler = sysrq_handle_unraw,
89 .help_msg = "unRaw",
90 .action_msg = "Keyboard mode set to XLATE",
91 .enable_mask = SYSRQ_ENABLE_KEYBOARD,
92 };
93 #else
94 #define sysrq_unraw_op (*(struct sysrq_key_op *)0)
95 #endif /* CONFIG_VT */
97 #ifdef CONFIG_KEXEC
98 static void sysrq_handle_crashdump(int key, struct pt_regs *pt_regs,
99 struct tty_struct *tty)
100 {
101 crash_kexec(pt_regs);
102 }
103 static struct sysrq_key_op sysrq_crashdump_op = {
104 .handler = sysrq_handle_crashdump,
105 .help_msg = "Crashdump",
106 .action_msg = "Trigger a crashdump",
107 .enable_mask = SYSRQ_ENABLE_DUMP,
108 };
109 #else
110 #define sysrq_crashdump_op (*(struct sysrq_key_op *)0)
111 #endif
113 static void sysrq_handle_reboot(int key, struct pt_regs *pt_regs,
114 struct tty_struct *tty)
115 {
116 local_irq_enable();
117 emergency_restart();
118 }
119 static struct sysrq_key_op sysrq_reboot_op = {
120 .handler = sysrq_handle_reboot,
121 .help_msg = "reBoot",
122 .action_msg = "Resetting",
123 .enable_mask = SYSRQ_ENABLE_BOOT,
124 };
126 static void sysrq_handle_sync(int key, struct pt_regs *pt_regs,
127 struct tty_struct *tty)
128 {
129 emergency_sync();
130 }
131 static struct sysrq_key_op sysrq_sync_op = {
132 .handler = sysrq_handle_sync,
133 .help_msg = "Sync",
134 .action_msg = "Emergency Sync",
135 .enable_mask = SYSRQ_ENABLE_SYNC,
136 };
138 static void sysrq_handle_mountro(int key, struct pt_regs *pt_regs,
139 struct tty_struct *tty)
140 {
141 emergency_remount();
142 }
143 static struct sysrq_key_op sysrq_mountro_op = {
144 .handler = sysrq_handle_mountro,
145 .help_msg = "Unmount",
146 .action_msg = "Emergency Remount R/O",
147 .enable_mask = SYSRQ_ENABLE_REMOUNT,
148 };
150 #ifdef CONFIG_LOCKDEP
151 static void sysrq_handle_showlocks(int key, struct pt_regs *pt_regs,
152 struct tty_struct *tty)
153 {
154 debug_show_all_locks();
155 }
157 static struct sysrq_key_op sysrq_showlocks_op = {
158 .handler = sysrq_handle_showlocks,
159 .help_msg = "show-all-locks(D)",
160 .action_msg = "Show Locks Held",
161 };
162 #else
163 #define sysrq_showlocks_op (*(struct sysrq_key_op *)0)
164 #endif
166 static void sysrq_handle_showregs(int key, struct pt_regs *pt_regs,
167 struct tty_struct *tty)
168 {
169 if (pt_regs)
170 show_regs(pt_regs);
171 }
172 static struct sysrq_key_op sysrq_showregs_op = {
173 .handler = sysrq_handle_showregs,
174 .help_msg = "showPc",
175 .action_msg = "Show Regs",
176 .enable_mask = SYSRQ_ENABLE_DUMP,
177 };
179 static void sysrq_handle_showstate(int key, struct pt_regs *pt_regs,
180 struct tty_struct *tty)
181 {
182 show_state();
183 }
184 static struct sysrq_key_op sysrq_showstate_op = {
185 .handler = sysrq_handle_showstate,
186 .help_msg = "showTasks",
187 .action_msg = "Show State",
188 .enable_mask = SYSRQ_ENABLE_DUMP,
189 };
191 static void sysrq_handle_showmem(int key, struct pt_regs *pt_regs,
192 struct tty_struct *tty)
193 {
194 show_mem();
195 }
196 static struct sysrq_key_op sysrq_showmem_op = {
197 .handler = sysrq_handle_showmem,
198 .help_msg = "showMem",
199 .action_msg = "Show Memory",
200 .enable_mask = SYSRQ_ENABLE_DUMP,
201 };
203 /*
204 * Signal sysrq helper function. Sends a signal to all user processes.
205 */
206 static void send_sig_all(int sig)
207 {
208 struct task_struct *p;
210 for_each_process(p) {
211 if (p->mm && p->pid != 1)
212 /* Not swapper, init nor kernel thread */
213 force_sig(sig, p);
214 }
215 }
217 static void sysrq_handle_term(int key, struct pt_regs *pt_regs,
218 struct tty_struct *tty)
219 {
220 send_sig_all(SIGTERM);
221 console_loglevel = 8;
222 }
223 static struct sysrq_key_op sysrq_term_op = {
224 .handler = sysrq_handle_term,
225 .help_msg = "tErm",
226 .action_msg = "Terminate All Tasks",
227 .enable_mask = SYSRQ_ENABLE_SIGNAL,
228 };
230 static void moom_callback(void *ignored)
231 {
232 out_of_memory(&NODE_DATA(0)->node_zonelists[ZONE_NORMAL],
233 GFP_KERNEL, 0);
234 }
236 static DECLARE_WORK(moom_work, moom_callback, NULL);
238 static void sysrq_handle_moom(int key, struct pt_regs *pt_regs,
239 struct tty_struct *tty)
240 {
241 schedule_work(&moom_work);
242 }
243 static struct sysrq_key_op sysrq_moom_op = {
244 .handler = sysrq_handle_moom,
245 .help_msg = "Full",
246 .action_msg = "Manual OOM execution",
247 };
249 static void sysrq_handle_kill(int key, struct pt_regs *pt_regs,
250 struct tty_struct *tty)
251 {
252 send_sig_all(SIGKILL);
253 console_loglevel = 8;
254 }
255 static struct sysrq_key_op sysrq_kill_op = {
256 .handler = sysrq_handle_kill,
257 .help_msg = "kIll",
258 .action_msg = "Kill All Tasks",
259 .enable_mask = SYSRQ_ENABLE_SIGNAL,
260 };
262 static void sysrq_handle_unrt(int key, struct pt_regs *pt_regs,
263 struct tty_struct *tty)
264 {
265 normalize_rt_tasks();
266 }
267 static struct sysrq_key_op sysrq_unrt_op = {
268 .handler = sysrq_handle_unrt,
269 .help_msg = "Nice",
270 .action_msg = "Nice All RT Tasks",
271 .enable_mask = SYSRQ_ENABLE_RTNICE,
272 };
274 /* Key Operations table and lock */
275 static DEFINE_SPINLOCK(sysrq_key_table_lock);
277 static struct sysrq_key_op *sysrq_key_table[36] = {
278 &sysrq_loglevel_op, /* 0 */
279 &sysrq_loglevel_op, /* 1 */
280 &sysrq_loglevel_op, /* 2 */
281 &sysrq_loglevel_op, /* 3 */
282 &sysrq_loglevel_op, /* 4 */
283 &sysrq_loglevel_op, /* 5 */
284 &sysrq_loglevel_op, /* 6 */
285 &sysrq_loglevel_op, /* 7 */
286 &sysrq_loglevel_op, /* 8 */
287 &sysrq_loglevel_op, /* 9 */
289 /*
290 * Don't use for system provided sysrqs, it is handled specially on
291 * sparc and will never arrive
292 */
293 NULL, /* a */
294 &sysrq_reboot_op, /* b */
295 &sysrq_crashdump_op, /* c */
296 &sysrq_showlocks_op, /* d */
297 &sysrq_term_op, /* e */
298 &sysrq_moom_op, /* f */
299 NULL, /* g */
300 NULL, /* h */
301 &sysrq_kill_op, /* i */
302 NULL, /* j */
303 &sysrq_SAK_op, /* k */
304 NULL, /* l */
305 &sysrq_showmem_op, /* m */
306 &sysrq_unrt_op, /* n */
307 /* This will often be registered as 'Off' at init time */
308 NULL, /* o */
309 &sysrq_showregs_op, /* p */
310 NULL, /* q */
311 &sysrq_unraw_op, /* r */
312 &sysrq_sync_op, /* s */
313 &sysrq_showstate_op, /* t */
314 &sysrq_mountro_op, /* u */
315 /* May be assigned at init time by SMP VOYAGER */
316 NULL, /* v */
317 NULL, /* w */
318 NULL, /* x */
319 NULL, /* y */
320 NULL /* z */
321 };
323 /* key2index calculation, -1 on invalid index */
324 static int sysrq_key_table_key2index(int key)
325 {
326 int retval;
328 if ((key >= '0') && (key <= '9'))
329 retval = key - '0';
330 else if ((key >= 'a') && (key <= 'z'))
331 retval = key + 10 - 'a';
332 else
333 retval = -1;
334 return retval;
335 }
337 /*
338 * get and put functions for the table, exposed to modules.
339 */
340 struct sysrq_key_op *__sysrq_get_key_op(int key)
341 {
342 struct sysrq_key_op *op_p = NULL;
343 int i;
345 i = sysrq_key_table_key2index(key);
346 if (i != -1)
347 op_p = sysrq_key_table[i];
348 return op_p;
349 }
351 static void __sysrq_put_key_op(int key, struct sysrq_key_op *op_p)
352 {
353 int i = sysrq_key_table_key2index(key);
355 if (i != -1)
356 sysrq_key_table[i] = op_p;
357 }
359 /*
360 * This is the non-locking version of handle_sysrq. It must/can only be called
361 * by sysrq key handlers, as they are inside of the lock
362 */
363 void __handle_sysrq(int key, struct pt_regs *pt_regs, struct tty_struct *tty,
364 int check_mask)
365 {
366 struct sysrq_key_op *op_p;
367 int orig_log_level;
368 int i;
369 unsigned long flags;
371 spin_lock_irqsave(&sysrq_key_table_lock, flags);
372 orig_log_level = console_loglevel;
373 console_loglevel = 7;
374 printk(KERN_INFO "SysRq : ");
376 op_p = __sysrq_get_key_op(key);
377 if (op_p) {
378 /*
379 * Should we check for enabled operations (/proc/sysrq-trigger
380 * should not) and is the invoked operation enabled?
381 */
382 if (!check_mask || sysrq_enabled == 1 ||
383 (sysrq_enabled & op_p->enable_mask)) {
384 printk("%s\n", op_p->action_msg);
385 console_loglevel = orig_log_level;
386 op_p->handler(key, pt_regs, tty);
387 } else {
388 printk("This sysrq operation is disabled.\n");
389 }
390 } else {
391 printk("HELP : ");
392 /* Only print the help msg once per handler */
393 for (i = 0; i < ARRAY_SIZE(sysrq_key_table); i++) {
394 if (sysrq_key_table[i]) {
395 int j;
397 for (j = 0; sysrq_key_table[i] !=
398 sysrq_key_table[j]; j++)
399 ;
400 if (j != i)
401 continue;
402 printk("%s ", sysrq_key_table[i]->help_msg);
403 }
404 }
405 printk("\n");
406 console_loglevel = orig_log_level;
407 }
408 spin_unlock_irqrestore(&sysrq_key_table_lock, flags);
409 }
411 /*
412 * This function is called by the keyboard handler when SysRq is pressed
413 * and any other keycode arrives.
414 */
415 void handle_sysrq(int key, struct pt_regs *pt_regs, struct tty_struct *tty)
416 {
417 if (!sysrq_enabled)
418 return;
419 __handle_sysrq(key, pt_regs, tty, 1);
420 }
421 EXPORT_SYMBOL(handle_sysrq);
423 static int __sysrq_swap_key_ops(int key, struct sysrq_key_op *insert_op_p,
424 struct sysrq_key_op *remove_op_p)
425 {
427 int retval;
428 unsigned long flags;
430 spin_lock_irqsave(&sysrq_key_table_lock, flags);
431 if (__sysrq_get_key_op(key) == remove_op_p) {
432 __sysrq_put_key_op(key, insert_op_p);
433 retval = 0;
434 } else {
435 retval = -1;
436 }
437 spin_unlock_irqrestore(&sysrq_key_table_lock, flags);
438 return retval;
439 }
441 int register_sysrq_key(int key, struct sysrq_key_op *op_p)
442 {
443 return __sysrq_swap_key_ops(key, op_p, NULL);
444 }
445 EXPORT_SYMBOL(register_sysrq_key);
447 int unregister_sysrq_key(int key, struct sysrq_key_op *op_p)
448 {
449 return __sysrq_swap_key_ops(key, NULL, op_p);
450 }
451 EXPORT_SYMBOL(unregister_sysrq_key);