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Dmitry Torokhov97f5f0c2010-03-21 22:31:26 -07001/*
Linus Torvalds1da177e2005-04-16 15:20:36 -07002 * 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
Dmitry Torokhov97f5f0c2010-03-21 22:31:26 -070010 *
11 * Copyright (c) 2010 Dmitry Torokhov
12 * Input handler conversion
Linus Torvalds1da177e2005-04-16 15:20:36 -070013 */
14
Dmitry Torokhov97f5f0c2010-03-21 22:31:26 -070015#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
16
Linus Torvalds1da177e2005-04-16 15:20:36 -070017#include <linux/sched.h>
Clark Williams8bd75c72013-02-07 09:47:07 -060018#include <linux/sched/rt.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070019#include <linux/interrupt.h>
20#include <linux/mm.h>
21#include <linux/fs.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070022#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>
Alexey Dobriyanf40cbaa2008-10-15 22:04:23 -070028#include <linux/proc_fs.h>
Ingo Molnarc1dc0b92009-08-02 11:28:21 +020029#include <linux/nmi.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070030#include <linux/quotaops.h>
Ingo Molnarcdd6c482009-09-21 12:02:48 +020031#include <linux/perf_event.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070032#include <linux/kernel.h>
33#include <linux/module.h>
34#include <linux/suspend.h>
35#include <linux/writeback.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070036#include <linux/swap.h>
37#include <linux/spinlock.h>
38#include <linux/vt_kern.h>
39#include <linux/workqueue.h>
Ingo Molnar88ad0bf62007-02-16 01:28:16 -080040#include <linux/hrtimer.h>
David Rientjes5a3135c22007-10-16 23:25:53 -070041#include <linux/oom.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090042#include <linux/slab.h>
Dmitry Torokhov97f5f0c2010-03-21 22:31:26 -070043#include <linux/input.h>
Al Viroff01bb482011-09-16 02:31:11 -040044#include <linux/uaccess.h>
Mathieu Poirier154b7a42013-01-06 23:23:33 -080045#include <linux/moduleparam.h>
Mathieu J. Poirier39030782013-04-01 22:14:19 -070046#include <linux/jiffies.h>
Mathieu J. Poirier3d289512013-06-05 22:51:46 -070047#include <linux/syscalls.h>
Mathieu J. Poirier4c076eb2013-08-03 17:22:08 -070048#include <linux/of.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070049
50#include <asm/ptrace.h>
Heiko Carstens2033b0c2006-10-06 16:38:42 +020051#include <asm/irq_regs.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070052
53/* Whether we react on sysrq keys or just ignore them */
Ben Hutchings8eaede42013-10-07 01:05:46 +010054static int __read_mostly sysrq_enabled = CONFIG_MAGIC_SYSRQ_DEFAULT_ENABLE;
Dmitry Torokhov97f5f0c2010-03-21 22:31:26 -070055static bool __read_mostly sysrq_always_enabled;
Ingo Molnar5d6f6472006-12-13 00:34:36 -080056
Mathieu J. Poirier39030782013-04-01 22:14:19 -070057unsigned short platform_sysrq_reset_seq[] __weak = { KEY_RESERVED };
58int sysrq_reset_downtime_ms __weak;
59
Dmitry Torokhov97f5f0c2010-03-21 22:31:26 -070060static bool sysrq_on(void)
Ingo Molnar5d6f6472006-12-13 00:34:36 -080061{
Dmitry Torokhov97f5f0c2010-03-21 22:31:26 -070062 return sysrq_enabled || sysrq_always_enabled;
Ingo Molnar5d6f6472006-12-13 00:34:36 -080063}
64
65/*
66 * A value of 1 means 'all', other nonzero values are an op mask:
67 */
Dmitry Torokhov97f5f0c2010-03-21 22:31:26 -070068static bool sysrq_on_mask(int mask)
Ingo Molnar5d6f6472006-12-13 00:34:36 -080069{
Dmitry Torokhov97f5f0c2010-03-21 22:31:26 -070070 return sysrq_always_enabled ||
71 sysrq_enabled == 1 ||
72 (sysrq_enabled & mask);
Ingo Molnar5d6f6472006-12-13 00:34:36 -080073}
74
75static int __init sysrq_always_enabled_setup(char *str)
76{
Dmitry Torokhov97f5f0c2010-03-21 22:31:26 -070077 sysrq_always_enabled = true;
78 pr_info("sysrq always enabled.\n");
Ingo Molnar5d6f6472006-12-13 00:34:36 -080079
80 return 1;
81}
82
83__setup("sysrq_always_enabled", sysrq_always_enabled_setup);
84
Linus Torvalds1da177e2005-04-16 15:20:36 -070085
Dmitry Torokhov1495cc92010-08-17 21:15:46 -070086static void sysrq_handle_loglevel(int key)
Linus Torvalds1da177e2005-04-16 15:20:36 -070087{
88 int i;
Dmitry Torokhov97f5f0c2010-03-21 22:31:26 -070089
Linus Torvalds1da177e2005-04-16 15:20:36 -070090 i = key - '0';
91 console_loglevel = 7;
92 printk("Loglevel set to %d\n", i);
93 console_loglevel = i;
Andrew Mortonbf36b902006-03-25 03:07:08 -080094}
Linus Torvalds1da177e2005-04-16 15:20:36 -070095static struct sysrq_key_op sysrq_loglevel_op = {
96 .handler = sysrq_handle_loglevel,
Randy Dunlap208b95c2009-01-06 14:41:13 -080097 .help_msg = "loglevel(0-9)",
Linus Torvalds1da177e2005-04-16 15:20:36 -070098 .action_msg = "Changing Loglevel",
99 .enable_mask = SYSRQ_ENABLE_LOG,
100};
101
Linus Torvalds1da177e2005-04-16 15:20:36 -0700102#ifdef CONFIG_VT
Dmitry Torokhov1495cc92010-08-17 21:15:46 -0700103static void sysrq_handle_SAK(int key)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700104{
Eric W. Biederman8b6312f2007-02-10 01:44:34 -0800105 struct work_struct *SAK_work = &vc_cons[fg_console].SAK_work;
Eric W. Biederman8b6312f2007-02-10 01:44:34 -0800106 schedule_work(SAK_work);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700107}
108static struct sysrq_key_op sysrq_SAK_op = {
109 .handler = sysrq_handle_SAK,
zhangwei(Jovi)afa80cc2013-03-07 17:00:02 +0800110 .help_msg = "sak(k)",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700111 .action_msg = "SAK",
112 .enable_mask = SYSRQ_ENABLE_KEYBOARD,
113};
Andrew Mortonbf36b902006-03-25 03:07:08 -0800114#else
Dmitry Torokhov97f5f0c2010-03-21 22:31:26 -0700115#define sysrq_SAK_op (*(struct sysrq_key_op *)NULL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700116#endif
117
118#ifdef CONFIG_VT
Dmitry Torokhov1495cc92010-08-17 21:15:46 -0700119static void sysrq_handle_unraw(int key)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700120{
Alan Cox079c9532012-02-28 14:49:23 +0000121 vt_reset_unicode(fg_console);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700122}
Alan Cox079c9532012-02-28 14:49:23 +0000123
Linus Torvalds1da177e2005-04-16 15:20:36 -0700124static struct sysrq_key_op sysrq_unraw_op = {
125 .handler = sysrq_handle_unraw,
zhangwei(Jovi)afa80cc2013-03-07 17:00:02 +0800126 .help_msg = "unraw(r)",
Bill Nottingham2e8ecb92007-10-16 23:29:38 -0700127 .action_msg = "Keyboard mode set to system default",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700128 .enable_mask = SYSRQ_ENABLE_KEYBOARD,
129};
Andrew Mortonbf36b902006-03-25 03:07:08 -0800130#else
Dmitry Torokhov97f5f0c2010-03-21 22:31:26 -0700131#define sysrq_unraw_op (*(struct sysrq_key_op *)NULL)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700132#endif /* CONFIG_VT */
133
Dmitry Torokhov1495cc92010-08-17 21:15:46 -0700134static void sysrq_handle_crash(int key)
Hariprasad Nellitheertha86b1ae32005-06-25 14:58:25 -0700135{
Neil Hormand6580a92009-06-17 16:28:17 -0700136 char *killer = NULL;
Hidetoshi Setocab8bd32009-07-29 15:04:14 -0700137
138 panic_on_oops = 1; /* force panic */
139 wmb();
Neil Hormand6580a92009-06-17 16:28:17 -0700140 *killer = 1;
Hariprasad Nellitheertha86b1ae32005-06-25 14:58:25 -0700141}
Hidetoshi Setocab8bd32009-07-29 15:04:14 -0700142static struct sysrq_key_op sysrq_crash_op = {
Neil Hormand6580a92009-06-17 16:28:17 -0700143 .handler = sysrq_handle_crash,
zhangwei(Jovi)afa80cc2013-03-07 17:00:02 +0800144 .help_msg = "crash(c)",
Neil Hormand6580a92009-06-17 16:28:17 -0700145 .action_msg = "Trigger a crash",
Hariprasad Nellitheertha86b1ae32005-06-25 14:58:25 -0700146 .enable_mask = SYSRQ_ENABLE_DUMP,
147};
Hariprasad Nellitheertha86b1ae32005-06-25 14:58:25 -0700148
Dmitry Torokhov1495cc92010-08-17 21:15:46 -0700149static void sysrq_handle_reboot(int key)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700150{
Peter Zijlstrab2e9c7d2006-09-30 23:28:02 -0700151 lockdep_off();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700152 local_irq_enable();
Eric W. Biederman4de8b9b2005-07-26 11:51:06 -0600153 emergency_restart();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700154}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700155static struct sysrq_key_op sysrq_reboot_op = {
156 .handler = sysrq_handle_reboot,
zhangwei(Jovi)afa80cc2013-03-07 17:00:02 +0800157 .help_msg = "reboot(b)",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700158 .action_msg = "Resetting",
159 .enable_mask = SYSRQ_ENABLE_BOOT,
160};
161
Dmitry Torokhov1495cc92010-08-17 21:15:46 -0700162static void sysrq_handle_sync(int key)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700163{
164 emergency_sync();
165}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700166static struct sysrq_key_op sysrq_sync_op = {
167 .handler = sysrq_handle_sync,
zhangwei(Jovi)afa80cc2013-03-07 17:00:02 +0800168 .help_msg = "sync(s)",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700169 .action_msg = "Emergency Sync",
170 .enable_mask = SYSRQ_ENABLE_SYNC,
171};
172
Dmitry Torokhov1495cc92010-08-17 21:15:46 -0700173static void sysrq_handle_show_timers(int key)
Ingo Molnar88ad0bf62007-02-16 01:28:16 -0800174{
175 sysrq_timer_list_show();
176}
177
178static struct sysrq_key_op sysrq_show_timers_op = {
179 .handler = sysrq_handle_show_timers,
zhangwei(Jovi)afa80cc2013-03-07 17:00:02 +0800180 .help_msg = "show-all-timers(q)",
Thomas Gleixner322acf62008-10-20 12:33:14 +0200181 .action_msg = "Show clockevent devices & pending hrtimers (no others)",
Ingo Molnar88ad0bf62007-02-16 01:28:16 -0800182};
183
Dmitry Torokhov1495cc92010-08-17 21:15:46 -0700184static void sysrq_handle_mountro(int key)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700185{
186 emergency_remount();
187}
Linus Torvalds1da177e2005-04-16 15:20:36 -0700188static struct sysrq_key_op sysrq_mountro_op = {
189 .handler = sysrq_handle_mountro,
zhangwei(Jovi)afa80cc2013-03-07 17:00:02 +0800190 .help_msg = "unmount(u)",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700191 .action_msg = "Emergency Remount R/O",
192 .enable_mask = SYSRQ_ENABLE_REMOUNT,
193};
194
Ingo Molnar8c645802006-07-03 00:24:56 -0700195#ifdef CONFIG_LOCKDEP
Dmitry Torokhov1495cc92010-08-17 21:15:46 -0700196static void sysrq_handle_showlocks(int key)
Ingo Molnarde5097c2006-01-09 15:59:21 -0800197{
Ingo Molnar9a11b49a2006-07-03 00:24:33 -0700198 debug_show_all_locks();
Ingo Molnarde5097c2006-01-09 15:59:21 -0800199}
Ingo Molnar8c645802006-07-03 00:24:56 -0700200
Ingo Molnarde5097c2006-01-09 15:59:21 -0800201static struct sysrq_key_op sysrq_showlocks_op = {
202 .handler = sysrq_handle_showlocks,
zhangwei(Jovi)afa80cc2013-03-07 17:00:02 +0800203 .help_msg = "show-all-locks(d)",
Ingo Molnarde5097c2006-01-09 15:59:21 -0800204 .action_msg = "Show Locks Held",
205};
Andrew Mortonbf36b902006-03-25 03:07:08 -0800206#else
Dmitry Torokhov97f5f0c2010-03-21 22:31:26 -0700207#define sysrq_showlocks_op (*(struct sysrq_key_op *)NULL)
Ingo Molnarde5097c2006-01-09 15:59:21 -0800208#endif
Linus Torvalds1da177e2005-04-16 15:20:36 -0700209
Rik van Riel5045bca2008-04-29 00:59:21 -0700210#ifdef CONFIG_SMP
211static DEFINE_SPINLOCK(show_lock);
212
213static void showacpu(void *dummy)
214{
215 unsigned long flags;
216
217 /* Idle CPUs have no interesting backtrace. */
218 if (idle_cpu(smp_processor_id()))
219 return;
220
221 spin_lock_irqsave(&show_lock, flags);
222 printk(KERN_INFO "CPU%d:\n", smp_processor_id());
223 show_stack(NULL, NULL);
224 spin_unlock_irqrestore(&show_lock, flags);
225}
226
227static void sysrq_showregs_othercpus(struct work_struct *dummy)
228{
Ingo Molnar8b604d52008-06-27 11:52:45 +0200229 smp_call_function(showacpu, NULL, 0);
Rik van Riel5045bca2008-04-29 00:59:21 -0700230}
231
232static DECLARE_WORK(sysrq_showallcpus, sysrq_showregs_othercpus);
233
Dmitry Torokhov1495cc92010-08-17 21:15:46 -0700234static void sysrq_handle_showallcpus(int key)
Rik van Riel5045bca2008-04-29 00:59:21 -0700235{
Ingo Molnar47cab6a2009-08-03 09:31:54 +0200236 /*
237 * Fall back to the workqueue based printing if the
238 * backtrace printing did not succeed or the
239 * architecture has no support for it:
240 */
241 if (!trigger_all_cpu_backtrace()) {
242 struct pt_regs *regs = get_irq_regs();
243
244 if (regs) {
245 printk(KERN_INFO "CPU%d:\n", smp_processor_id());
246 show_regs(regs);
247 }
248 schedule_work(&sysrq_showallcpus);
249 }
Rik van Riel5045bca2008-04-29 00:59:21 -0700250}
251
252static struct sysrq_key_op sysrq_showallcpus_op = {
253 .handler = sysrq_handle_showallcpus,
zhangwei(Jovi)afa80cc2013-03-07 17:00:02 +0800254 .help_msg = "show-backtrace-all-active-cpus(l)",
Rik van Riel5045bca2008-04-29 00:59:21 -0700255 .action_msg = "Show backtrace of all active CPUs",
256 .enable_mask = SYSRQ_ENABLE_DUMP,
257};
258#endif
259
Dmitry Torokhov1495cc92010-08-17 21:15:46 -0700260static void sysrq_handle_showregs(int key)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700261{
David Howells7d12e782006-10-05 14:55:46 +0100262 struct pt_regs *regs = get_irq_regs();
263 if (regs)
264 show_regs(regs);
Ingo Molnarcdd6c482009-09-21 12:02:48 +0200265 perf_event_print_debug();
Linus Torvalds1da177e2005-04-16 15:20:36 -0700266}
267static struct sysrq_key_op sysrq_showregs_op = {
268 .handler = sysrq_handle_showregs,
zhangwei(Jovi)afa80cc2013-03-07 17:00:02 +0800269 .help_msg = "show-registers(p)",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700270 .action_msg = "Show Regs",
271 .enable_mask = SYSRQ_ENABLE_DUMP,
272};
273
Dmitry Torokhov1495cc92010-08-17 21:15:46 -0700274static void sysrq_handle_showstate(int key)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700275{
276 show_state();
277}
278static struct sysrq_key_op sysrq_showstate_op = {
279 .handler = sysrq_handle_showstate,
zhangwei(Jovi)afa80cc2013-03-07 17:00:02 +0800280 .help_msg = "show-task-states(t)",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700281 .action_msg = "Show State",
282 .enable_mask = SYSRQ_ENABLE_DUMP,
283};
284
Dmitry Torokhov1495cc92010-08-17 21:15:46 -0700285static void sysrq_handle_showstate_blocked(int key)
Ingo Molnare59e2ae2006-12-06 20:35:59 -0800286{
287 show_state_filter(TASK_UNINTERRUPTIBLE);
288}
289static struct sysrq_key_op sysrq_showstate_blocked_op = {
290 .handler = sysrq_handle_showstate_blocked,
zhangwei(Jovi)afa80cc2013-03-07 17:00:02 +0800291 .help_msg = "show-blocked-tasks(w)",
Ingo Molnare59e2ae2006-12-06 20:35:59 -0800292 .action_msg = "Show Blocked State",
293 .enable_mask = SYSRQ_ENABLE_DUMP,
294};
295
Peter Zijlstra69f698a2008-11-01 19:53:34 +0100296#ifdef CONFIG_TRACING
297#include <linux/ftrace.h>
298
Dmitry Torokhov1495cc92010-08-17 21:15:46 -0700299static void sysrq_ftrace_dump(int key)
Peter Zijlstra69f698a2008-11-01 19:53:34 +0100300{
Frederic Weisbeckercecbca92010-04-18 19:08:41 +0200301 ftrace_dump(DUMP_ALL);
Peter Zijlstra69f698a2008-11-01 19:53:34 +0100302}
303static struct sysrq_key_op sysrq_ftrace_dump_op = {
304 .handler = sysrq_ftrace_dump,
zhangwei(Jovi)afa80cc2013-03-07 17:00:02 +0800305 .help_msg = "dump-ftrace-buffer(z)",
Peter Zijlstra69f698a2008-11-01 19:53:34 +0100306 .action_msg = "Dump ftrace buffer",
307 .enable_mask = SYSRQ_ENABLE_DUMP,
308};
309#else
Dmitry Torokhov97f5f0c2010-03-21 22:31:26 -0700310#define sysrq_ftrace_dump_op (*(struct sysrq_key_op *)NULL)
Peter Zijlstra69f698a2008-11-01 19:53:34 +0100311#endif
Ingo Molnare59e2ae2006-12-06 20:35:59 -0800312
Dmitry Torokhov1495cc92010-08-17 21:15:46 -0700313static void sysrq_handle_showmem(int key)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700314{
David Rientjesb2b755b2011-03-24 15:18:15 -0700315 show_mem(0);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700316}
317static struct sysrq_key_op sysrq_showmem_op = {
318 .handler = sysrq_handle_showmem,
zhangwei(Jovi)afa80cc2013-03-07 17:00:02 +0800319 .help_msg = "show-memory-usage(m)",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700320 .action_msg = "Show Memory",
321 .enable_mask = SYSRQ_ENABLE_DUMP,
322};
323
Andrew Mortonbf36b902006-03-25 03:07:08 -0800324/*
325 * Signal sysrq helper function. Sends a signal to all user processes.
326 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700327static void send_sig_all(int sig)
328{
329 struct task_struct *p;
330
Anton Vorontsove502bab2012-02-07 10:49:39 +0400331 read_lock(&tasklist_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700332 for_each_process(p) {
Anton Vorontsovd3a532a2012-02-07 10:49:51 +0400333 if (p->flags & PF_KTHREAD)
334 continue;
335 if (is_global_init(p))
336 continue;
337
Anton Vorontsovb82c3282012-04-05 14:25:05 -0700338 do_send_sig_info(sig, SEND_SIG_FORCED, p, true);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700339 }
Anton Vorontsove502bab2012-02-07 10:49:39 +0400340 read_unlock(&tasklist_lock);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700341}
342
Dmitry Torokhov1495cc92010-08-17 21:15:46 -0700343static void sysrq_handle_term(int key)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700344{
345 send_sig_all(SIGTERM);
346 console_loglevel = 8;
347}
348static struct sysrq_key_op sysrq_term_op = {
349 .handler = sysrq_handle_term,
zhangwei(Jovi)afa80cc2013-03-07 17:00:02 +0800350 .help_msg = "terminate-all-tasks(e)",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700351 .action_msg = "Terminate All Tasks",
352 .enable_mask = SYSRQ_ENABLE_SIGNAL,
353};
354
David Howells65f27f32006-11-22 14:55:48 +0000355static void moom_callback(struct work_struct *ignored)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700356{
David Rientjes53186092012-11-14 01:15:19 -0800357 out_of_memory(node_zonelist(first_online_node, GFP_KERNEL), GFP_KERNEL,
358 0, NULL, true);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700359}
360
David Howells65f27f32006-11-22 14:55:48 +0000361static DECLARE_WORK(moom_work, moom_callback);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700362
Dmitry Torokhov1495cc92010-08-17 21:15:46 -0700363static void sysrq_handle_moom(int key)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700364{
365 schedule_work(&moom_work);
366}
367static struct sysrq_key_op sysrq_moom_op = {
368 .handler = sysrq_handle_moom,
zhangwei(Jovi)afa80cc2013-03-07 17:00:02 +0800369 .help_msg = "memory-full-oom-kill(f)",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700370 .action_msg = "Manual OOM execution",
Naohiro Ooiwab4236f82008-10-15 22:01:43 -0700371 .enable_mask = SYSRQ_ENABLE_SIGNAL,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700372};
373
Eric Sandeenc2d75432009-03-31 15:23:46 -0700374#ifdef CONFIG_BLOCK
Dmitry Torokhov1495cc92010-08-17 21:15:46 -0700375static void sysrq_handle_thaw(int key)
Eric Sandeenc2d75432009-03-31 15:23:46 -0700376{
377 emergency_thaw_all();
378}
379static struct sysrq_key_op sysrq_thaw_op = {
380 .handler = sysrq_handle_thaw,
zhangwei(Jovi)afa80cc2013-03-07 17:00:02 +0800381 .help_msg = "thaw-filesystems(j)",
Eric Sandeenc2d75432009-03-31 15:23:46 -0700382 .action_msg = "Emergency Thaw of all frozen filesystems",
383 .enable_mask = SYSRQ_ENABLE_SIGNAL,
384};
385#endif
386
Dmitry Torokhov1495cc92010-08-17 21:15:46 -0700387static void sysrq_handle_kill(int key)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700388{
389 send_sig_all(SIGKILL);
390 console_loglevel = 8;
391}
392static struct sysrq_key_op sysrq_kill_op = {
393 .handler = sysrq_handle_kill,
zhangwei(Jovi)afa80cc2013-03-07 17:00:02 +0800394 .help_msg = "kill-all-tasks(i)",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700395 .action_msg = "Kill All Tasks",
396 .enable_mask = SYSRQ_ENABLE_SIGNAL,
397};
398
Dmitry Torokhov1495cc92010-08-17 21:15:46 -0700399static void sysrq_handle_unrt(int key)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700400{
401 normalize_rt_tasks();
402}
403static struct sysrq_key_op sysrq_unrt_op = {
404 .handler = sysrq_handle_unrt,
zhangwei(Jovi)afa80cc2013-03-07 17:00:02 +0800405 .help_msg = "nice-all-RT-tasks(n)",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700406 .action_msg = "Nice All RT Tasks",
407 .enable_mask = SYSRQ_ENABLE_RTNICE,
408};
409
410/* Key Operations table and lock */
411static DEFINE_SPINLOCK(sysrq_key_table_lock);
Andrew Mortonbf36b902006-03-25 03:07:08 -0800412
413static struct sysrq_key_op *sysrq_key_table[36] = {
414 &sysrq_loglevel_op, /* 0 */
415 &sysrq_loglevel_op, /* 1 */
416 &sysrq_loglevel_op, /* 2 */
417 &sysrq_loglevel_op, /* 3 */
418 &sysrq_loglevel_op, /* 4 */
419 &sysrq_loglevel_op, /* 5 */
420 &sysrq_loglevel_op, /* 6 */
421 &sysrq_loglevel_op, /* 7 */
422 &sysrq_loglevel_op, /* 8 */
423 &sysrq_loglevel_op, /* 9 */
424
425 /*
Randy Dunlapd346cce2007-01-31 23:48:17 -0800426 * a: Don't use for system provided sysrqs, it is handled specially on
427 * sparc and will never arrive.
Andrew Mortonbf36b902006-03-25 03:07:08 -0800428 */
429 NULL, /* a */
430 &sysrq_reboot_op, /* b */
Hidetoshi Setocab8bd32009-07-29 15:04:14 -0700431 &sysrq_crash_op, /* c & ibm_emac driver debug */
Andrew Mortonbf36b902006-03-25 03:07:08 -0800432 &sysrq_showlocks_op, /* d */
433 &sysrq_term_op, /* e */
434 &sysrq_moom_op, /* f */
Jason Wessel364b5b72009-05-13 21:56:59 -0500435 /* g: May be registered for the kernel debugger */
Andrew Mortonbf36b902006-03-25 03:07:08 -0800436 NULL, /* g */
Eric Sandeenc2d75432009-03-31 15:23:46 -0700437 NULL, /* h - reserved for help */
Andrew Mortonbf36b902006-03-25 03:07:08 -0800438 &sysrq_kill_op, /* i */
Eric Sandeenc2d75432009-03-31 15:23:46 -0700439#ifdef CONFIG_BLOCK
440 &sysrq_thaw_op, /* j */
441#else
Andrew Mortonbf36b902006-03-25 03:07:08 -0800442 NULL, /* j */
Eric Sandeenc2d75432009-03-31 15:23:46 -0700443#endif
Andrew Mortonbf36b902006-03-25 03:07:08 -0800444 &sysrq_SAK_op, /* k */
Rik van Riel5045bca2008-04-29 00:59:21 -0700445#ifdef CONFIG_SMP
446 &sysrq_showallcpus_op, /* l */
447#else
Andrew Mortonbf36b902006-03-25 03:07:08 -0800448 NULL, /* l */
Rik van Riel5045bca2008-04-29 00:59:21 -0700449#endif
Andrew Mortonbf36b902006-03-25 03:07:08 -0800450 &sysrq_showmem_op, /* m */
451 &sysrq_unrt_op, /* n */
Randy Dunlapd346cce2007-01-31 23:48:17 -0800452 /* o: This will often be registered as 'Off' at init time */
Andrew Mortonbf36b902006-03-25 03:07:08 -0800453 NULL, /* o */
454 &sysrq_showregs_op, /* p */
Ingo Molnar88ad0bf62007-02-16 01:28:16 -0800455 &sysrq_show_timers_op, /* q */
Randy Dunlapd346cce2007-01-31 23:48:17 -0800456 &sysrq_unraw_op, /* r */
Andrew Mortonbf36b902006-03-25 03:07:08 -0800457 &sysrq_sync_op, /* s */
458 &sysrq_showstate_op, /* t */
459 &sysrq_mountro_op, /* u */
Jason Wessel364b5b72009-05-13 21:56:59 -0500460 /* v: May be registered for frame buffer console restore */
Andrew Mortonbf36b902006-03-25 03:07:08 -0800461 NULL, /* v */
Randy Dunlapd346cce2007-01-31 23:48:17 -0800462 &sysrq_showstate_blocked_op, /* w */
463 /* x: May be registered on ppc/powerpc for xmon */
David S. Miller916ca142012-10-16 09:34:01 -0700464 /* x: May be registered on sparc64 for global PMU dump */
Randy Dunlapd346cce2007-01-31 23:48:17 -0800465 NULL, /* x */
David S. Miller93dae5b2008-05-19 23:46:00 -0700466 /* y: May be registered on sparc64 for global register dump */
Andrew Mortonbf36b902006-03-25 03:07:08 -0800467 NULL, /* y */
Peter Zijlstra69f698a2008-11-01 19:53:34 +0100468 &sysrq_ftrace_dump_op, /* z */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700469};
470
471/* key2index calculation, -1 on invalid index */
Andrew Mortonbf36b902006-03-25 03:07:08 -0800472static int sysrq_key_table_key2index(int key)
473{
Linus Torvalds1da177e2005-04-16 15:20:36 -0700474 int retval;
Andrew Mortonbf36b902006-03-25 03:07:08 -0800475
476 if ((key >= '0') && (key <= '9'))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700477 retval = key - '0';
Andrew Mortonbf36b902006-03-25 03:07:08 -0800478 else if ((key >= 'a') && (key <= 'z'))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700479 retval = key + 10 - 'a';
Andrew Mortonbf36b902006-03-25 03:07:08 -0800480 else
Linus Torvalds1da177e2005-04-16 15:20:36 -0700481 retval = -1;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700482 return retval;
483}
484
485/*
486 * get and put functions for the table, exposed to modules.
487 */
Andrew Mortonbf36b902006-03-25 03:07:08 -0800488struct sysrq_key_op *__sysrq_get_key_op(int key)
489{
490 struct sysrq_key_op *op_p = NULL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700491 int i;
Andrew Mortonbf36b902006-03-25 03:07:08 -0800492
Linus Torvalds1da177e2005-04-16 15:20:36 -0700493 i = sysrq_key_table_key2index(key);
Andrew Mortonbf36b902006-03-25 03:07:08 -0800494 if (i != -1)
495 op_p = sysrq_key_table[i];
Dmitry Torokhov97f5f0c2010-03-21 22:31:26 -0700496
Linus Torvalds1da177e2005-04-16 15:20:36 -0700497 return op_p;
498}
499
Andrew Mortonbf36b902006-03-25 03:07:08 -0800500static void __sysrq_put_key_op(int key, struct sysrq_key_op *op_p)
501{
502 int i = sysrq_key_table_key2index(key);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700503
Linus Torvalds1da177e2005-04-16 15:20:36 -0700504 if (i != -1)
505 sysrq_key_table[i] = op_p;
506}
507
Dmitry Torokhovf3353972010-08-17 21:15:47 -0700508void __handle_sysrq(int key, bool check_mask)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700509{
510 struct sysrq_key_op *op_p;
511 int orig_log_level;
Andrew Mortonbf36b902006-03-25 03:07:08 -0800512 int i;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700513 unsigned long flags;
514
515 spin_lock_irqsave(&sysrq_key_table_lock, flags);
Andy Whitcroftfb144ad2009-01-15 13:50:52 -0800516 /*
517 * Raise the apparent loglevel to maximum so that the sysrq header
518 * is shown to provide the user with positive feedback. We do not
519 * simply emit this at KERN_EMERG as that would change message
520 * routing in the consumers of /proc/kmsg.
521 */
Linus Torvalds1da177e2005-04-16 15:20:36 -0700522 orig_log_level = console_loglevel;
523 console_loglevel = 7;
524 printk(KERN_INFO "SysRq : ");
525
526 op_p = __sysrq_get_key_op(key);
527 if (op_p) {
Andrew Mortonbf36b902006-03-25 03:07:08 -0800528 /*
529 * Should we check for enabled operations (/proc/sysrq-trigger
530 * should not) and is the invoked operation enabled?
531 */
Ingo Molnar5d6f6472006-12-13 00:34:36 -0800532 if (!check_mask || sysrq_on_mask(op_p->enable_mask)) {
Andrew Mortonbf36b902006-03-25 03:07:08 -0800533 printk("%s\n", op_p->action_msg);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700534 console_loglevel = orig_log_level;
Dmitry Torokhov1495cc92010-08-17 21:15:46 -0700535 op_p->handler(key);
Andrew Mortonbf36b902006-03-25 03:07:08 -0800536 } else {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700537 printk("This sysrq operation is disabled.\n");
Andrew Mortonbf36b902006-03-25 03:07:08 -0800538 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700539 } else {
540 printk("HELP : ");
541 /* Only print the help msg once per handler */
Andrew Mortonbf36b902006-03-25 03:07:08 -0800542 for (i = 0; i < ARRAY_SIZE(sysrq_key_table); i++) {
543 if (sysrq_key_table[i]) {
544 int j;
545
546 for (j = 0; sysrq_key_table[i] !=
547 sysrq_key_table[j]; j++)
548 ;
549 if (j != i)
550 continue;
551 printk("%s ", sysrq_key_table[i]->help_msg);
552 }
Linus Torvalds1da177e2005-04-16 15:20:36 -0700553 }
Andrew Mortonbf36b902006-03-25 03:07:08 -0800554 printk("\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -0700555 console_loglevel = orig_log_level;
556 }
557 spin_unlock_irqrestore(&sysrq_key_table_lock, flags);
558}
559
Dmitry Torokhovf3353972010-08-17 21:15:47 -0700560void handle_sysrq(int key)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700561{
Ingo Molnar5d6f6472006-12-13 00:34:36 -0800562 if (sysrq_on())
Dmitry Torokhovf3353972010-08-17 21:15:47 -0700563 __handle_sysrq(key, true);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700564}
Andrew Mortonbf36b902006-03-25 03:07:08 -0800565EXPORT_SYMBOL(handle_sysrq);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700566
Dmitry Torokhov97f5f0c2010-03-21 22:31:26 -0700567#ifdef CONFIG_INPUT
568
569/* Simple translation table for the SysRq keys */
Dmitry Torokhovfcb71932010-11-15 00:23:42 -0800570static const unsigned char sysrq_xlate[KEY_CNT] =
Dmitry Torokhov97f5f0c2010-03-21 22:31:26 -0700571 "\000\0331234567890-=\177\t" /* 0x00 - 0x0f */
572 "qwertyuiop[]\r\000as" /* 0x10 - 0x1f */
573 "dfghjkl;'`\000\\zxcv" /* 0x20 - 0x2f */
574 "bnm,./\000*\000 \000\201\202\203\204\205" /* 0x30 - 0x3f */
575 "\206\207\210\211\212\000\000789-456+1" /* 0x40 - 0x4f */
576 "230\177\000\000\213\214\000\000\000\000\000\000\000\000\000\000" /* 0x50 - 0x5f */
577 "\r\000/"; /* 0x60 - 0x6f */
578
Dmitry Torokhovfcb71932010-11-15 00:23:42 -0800579struct sysrq_state {
580 struct input_handle handle;
581 struct work_struct reinject_work;
582 unsigned long key_down[BITS_TO_LONGS(KEY_CNT)];
583 unsigned int alt;
584 unsigned int alt_use;
585 bool active;
586 bool need_reinject;
Dmitry Torokhov7ab7b5a2011-02-02 22:59:54 -0800587 bool reinjecting;
Mathieu Poirier154b7a42013-01-06 23:23:33 -0800588
589 /* reset sequence handling */
590 bool reset_canceled;
Mathieu J. Poirier3d289512013-06-05 22:51:46 -0700591 bool reset_requested;
Mathieu Poirier154b7a42013-01-06 23:23:33 -0800592 unsigned long reset_keybit[BITS_TO_LONGS(KEY_CNT)];
593 int reset_seq_len;
594 int reset_seq_cnt;
595 int reset_seq_version;
Mathieu J. Poirier39030782013-04-01 22:14:19 -0700596 struct timer_list keyreset_timer;
Dmitry Torokhovfcb71932010-11-15 00:23:42 -0800597};
Dmitry Torokhov97f5f0c2010-03-21 22:31:26 -0700598
Mathieu Poirier154b7a42013-01-06 23:23:33 -0800599#define SYSRQ_KEY_RESET_MAX 20 /* Should be plenty */
600static unsigned short sysrq_reset_seq[SYSRQ_KEY_RESET_MAX];
601static unsigned int sysrq_reset_seq_len;
602static unsigned int sysrq_reset_seq_version = 1;
603
604static void sysrq_parse_reset_sequence(struct sysrq_state *state)
605{
606 int i;
607 unsigned short key;
608
609 state->reset_seq_cnt = 0;
610
611 for (i = 0; i < sysrq_reset_seq_len; i++) {
612 key = sysrq_reset_seq[i];
613
614 if (key == KEY_RESERVED || key > KEY_MAX)
615 break;
616
617 __set_bit(key, state->reset_keybit);
618 state->reset_seq_len++;
619
620 if (test_bit(key, state->key_down))
621 state->reset_seq_cnt++;
622 }
623
624 /* Disable reset until old keys are not released */
625 state->reset_canceled = state->reset_seq_cnt != 0;
626
627 state->reset_seq_version = sysrq_reset_seq_version;
628}
629
Mathieu J. Poirier3d289512013-06-05 22:51:46 -0700630static void sysrq_do_reset(unsigned long _state)
Mathieu J. Poirier39030782013-04-01 22:14:19 -0700631{
Mathieu J. Poirier3d289512013-06-05 22:51:46 -0700632 struct sysrq_state *state = (struct sysrq_state *) _state;
633
634 state->reset_requested = true;
635
636 sys_sync();
637 kernel_restart(NULL);
Mathieu J. Poirier39030782013-04-01 22:14:19 -0700638}
639
640static void sysrq_handle_reset_request(struct sysrq_state *state)
641{
Mathieu J. Poirier3d289512013-06-05 22:51:46 -0700642 if (state->reset_requested)
643 __handle_sysrq(sysrq_xlate[KEY_B], false);
644
Mathieu J. Poirier39030782013-04-01 22:14:19 -0700645 if (sysrq_reset_downtime_ms)
646 mod_timer(&state->keyreset_timer,
647 jiffies + msecs_to_jiffies(sysrq_reset_downtime_ms));
648 else
Mathieu J. Poirier3d289512013-06-05 22:51:46 -0700649 sysrq_do_reset((unsigned long)state);
Mathieu J. Poirier39030782013-04-01 22:14:19 -0700650}
651
652static void sysrq_detect_reset_sequence(struct sysrq_state *state,
Mathieu Poirier154b7a42013-01-06 23:23:33 -0800653 unsigned int code, int value)
654{
655 if (!test_bit(code, state->reset_keybit)) {
656 /*
657 * Pressing any key _not_ in reset sequence cancels
Mathieu J. Poirier39030782013-04-01 22:14:19 -0700658 * the reset sequence. Also cancelling the timer in
659 * case additional keys were pressed after a reset
660 * has been requested.
Mathieu Poirier154b7a42013-01-06 23:23:33 -0800661 */
Mathieu J. Poirier39030782013-04-01 22:14:19 -0700662 if (value && state->reset_seq_cnt) {
Mathieu Poirier154b7a42013-01-06 23:23:33 -0800663 state->reset_canceled = true;
Mathieu J. Poirier39030782013-04-01 22:14:19 -0700664 del_timer(&state->keyreset_timer);
665 }
Mathieu Poirier154b7a42013-01-06 23:23:33 -0800666 } else if (value == 0) {
Mathieu J. Poirier39030782013-04-01 22:14:19 -0700667 /*
668 * Key release - all keys in the reset sequence need
669 * to be pressed and held for the reset timeout
670 * to hold.
671 */
672 del_timer(&state->keyreset_timer);
673
Mathieu Poirier154b7a42013-01-06 23:23:33 -0800674 if (--state->reset_seq_cnt == 0)
675 state->reset_canceled = false;
676 } else if (value == 1) {
677 /* key press, not autorepeat */
678 if (++state->reset_seq_cnt == state->reset_seq_len &&
679 !state->reset_canceled) {
Mathieu J. Poirier39030782013-04-01 22:14:19 -0700680 sysrq_handle_reset_request(state);
Mathieu Poirier154b7a42013-01-06 23:23:33 -0800681 }
682 }
Mathieu Poirier154b7a42013-01-06 23:23:33 -0800683}
684
Mathieu J. Poirier4c076eb2013-08-03 17:22:08 -0700685#ifdef CONFIG_OF
686static void sysrq_of_get_keyreset_config(void)
687{
688 u32 key;
689 struct device_node *np;
690 struct property *prop;
691 const __be32 *p;
692
693 np = of_find_node_by_path("/chosen/linux,sysrq-reset-seq");
694 if (!np) {
695 pr_debug("No sysrq node found");
696 return;
697 }
698
699 /* Reset in case a __weak definition was present */
700 sysrq_reset_seq_len = 0;
701
702 of_property_for_each_u32(np, "keyset", prop, p, key) {
703 if (key == KEY_RESERVED || key > KEY_MAX ||
704 sysrq_reset_seq_len == SYSRQ_KEY_RESET_MAX)
705 break;
706
707 sysrq_reset_seq[sysrq_reset_seq_len++] = (unsigned short)key;
708 }
709
710 /* Get reset timeout if any. */
711 of_property_read_u32(np, "timeout-ms", &sysrq_reset_downtime_ms);
712}
713#else
714static void sysrq_of_get_keyreset_config(void)
715{
716}
717#endif
718
Dmitry Torokhovfcb71932010-11-15 00:23:42 -0800719static void sysrq_reinject_alt_sysrq(struct work_struct *work)
Dmitry Torokhov97f5f0c2010-03-21 22:31:26 -0700720{
Dmitry Torokhovfcb71932010-11-15 00:23:42 -0800721 struct sysrq_state *sysrq =
722 container_of(work, struct sysrq_state, reinject_work);
723 struct input_handle *handle = &sysrq->handle;
724 unsigned int alt_code = sysrq->alt_use;
725
726 if (sysrq->need_reinject) {
Dmitry Torokhov7ab7b5a2011-02-02 22:59:54 -0800727 /* we do not want the assignment to be reordered */
728 sysrq->reinjecting = true;
729 mb();
730
Dmitry Torokhovfcb71932010-11-15 00:23:42 -0800731 /* Simulate press and release of Alt + SysRq */
732 input_inject_event(handle, EV_KEY, alt_code, 1);
733 input_inject_event(handle, EV_KEY, KEY_SYSRQ, 1);
734 input_inject_event(handle, EV_SYN, SYN_REPORT, 1);
735
736 input_inject_event(handle, EV_KEY, KEY_SYSRQ, 0);
737 input_inject_event(handle, EV_KEY, alt_code, 0);
738 input_inject_event(handle, EV_SYN, SYN_REPORT, 1);
Dmitry Torokhov7ab7b5a2011-02-02 22:59:54 -0800739
740 mb();
741 sysrq->reinjecting = false;
Dmitry Torokhovfcb71932010-11-15 00:23:42 -0800742 }
743}
744
Mathieu Poirier154b7a42013-01-06 23:23:33 -0800745static bool sysrq_handle_keypress(struct sysrq_state *sysrq,
746 unsigned int code, int value)
747{
748 bool was_active = sysrq->active;
749 bool suppress;
750
751 switch (code) {
752
753 case KEY_LEFTALT:
754 case KEY_RIGHTALT:
755 if (!value) {
756 /* One of ALTs is being released */
757 if (sysrq->active && code == sysrq->alt_use)
758 sysrq->active = false;
759
760 sysrq->alt = KEY_RESERVED;
761
762 } else if (value != 2) {
763 sysrq->alt = code;
764 sysrq->need_reinject = false;
765 }
766 break;
767
768 case KEY_SYSRQ:
769 if (value == 1 && sysrq->alt != KEY_RESERVED) {
770 sysrq->active = true;
771 sysrq->alt_use = sysrq->alt;
772 /*
773 * If nothing else will be pressed we'll need
774 * to re-inject Alt-SysRq keysroke.
775 */
776 sysrq->need_reinject = true;
777 }
778
779 /*
780 * Pretend that sysrq was never pressed at all. This
781 * is needed to properly handle KGDB which will try
782 * to release all keys after exiting debugger. If we
783 * do not clear key bit it KGDB will end up sending
784 * release events for Alt and SysRq, potentially
785 * triggering print screen function.
786 */
787 if (sysrq->active)
788 clear_bit(KEY_SYSRQ, sysrq->handle.dev->key);
789
790 break;
791
792 default:
793 if (sysrq->active && value && value != 2) {
794 sysrq->need_reinject = false;
795 __handle_sysrq(sysrq_xlate[code], true);
796 }
797 break;
798 }
799
800 suppress = sysrq->active;
801
802 if (!sysrq->active) {
803
804 /*
805 * See if reset sequence has changed since the last time.
806 */
807 if (sysrq->reset_seq_version != sysrq_reset_seq_version)
808 sysrq_parse_reset_sequence(sysrq);
809
810 /*
811 * If we are not suppressing key presses keep track of
812 * keyboard state so we can release keys that have been
813 * pressed before entering SysRq mode.
814 */
815 if (value)
816 set_bit(code, sysrq->key_down);
817 else
818 clear_bit(code, sysrq->key_down);
819
820 if (was_active)
821 schedule_work(&sysrq->reinject_work);
822
Mathieu J. Poirier39030782013-04-01 22:14:19 -0700823 /* Check for reset sequence */
824 sysrq_detect_reset_sequence(sysrq, code, value);
Mathieu Poirier154b7a42013-01-06 23:23:33 -0800825
826 } else if (value == 0 && test_and_clear_bit(code, sysrq->key_down)) {
827 /*
828 * Pass on release events for keys that was pressed before
829 * entering SysRq mode.
830 */
831 suppress = false;
832 }
833
834 return suppress;
835}
836
Dmitry Torokhovfcb71932010-11-15 00:23:42 -0800837static bool sysrq_filter(struct input_handle *handle,
838 unsigned int type, unsigned int code, int value)
839{
840 struct sysrq_state *sysrq = handle->private;
Dmitry Torokhov1966cb22010-09-29 18:04:21 -0700841 bool suppress;
842
Dmitry Torokhov7ab7b5a2011-02-02 22:59:54 -0800843 /*
844 * Do not filter anything if we are in the process of re-injecting
845 * Alt+SysRq combination.
846 */
847 if (sysrq->reinjecting)
848 return false;
849
Dmitry Torokhovfcb71932010-11-15 00:23:42 -0800850 switch (type) {
Dmitry Torokhov1966cb22010-09-29 18:04:21 -0700851
Dmitry Torokhovfcb71932010-11-15 00:23:42 -0800852 case EV_SYN:
853 suppress = false;
Dmitry Torokhov97f5f0c2010-03-21 22:31:26 -0700854 break;
855
Dmitry Torokhovfcb71932010-11-15 00:23:42 -0800856 case EV_KEY:
Mathieu Poirier154b7a42013-01-06 23:23:33 -0800857 suppress = sysrq_handle_keypress(sysrq, code, value);
Dmitry Torokhov97f5f0c2010-03-21 22:31:26 -0700858 break;
859
860 default:
Dmitry Torokhovfcb71932010-11-15 00:23:42 -0800861 suppress = sysrq->active;
Dmitry Torokhov97f5f0c2010-03-21 22:31:26 -0700862 break;
863 }
864
Dmitry Torokhov1966cb22010-09-29 18:04:21 -0700865 return suppress;
Dmitry Torokhov97f5f0c2010-03-21 22:31:26 -0700866}
867
868static int sysrq_connect(struct input_handler *handler,
869 struct input_dev *dev,
870 const struct input_device_id *id)
871{
Dmitry Torokhovfcb71932010-11-15 00:23:42 -0800872 struct sysrq_state *sysrq;
Dmitry Torokhov97f5f0c2010-03-21 22:31:26 -0700873 int error;
874
Dmitry Torokhovfcb71932010-11-15 00:23:42 -0800875 sysrq = kzalloc(sizeof(struct sysrq_state), GFP_KERNEL);
876 if (!sysrq)
Dmitry Torokhov97f5f0c2010-03-21 22:31:26 -0700877 return -ENOMEM;
878
Dmitry Torokhovfcb71932010-11-15 00:23:42 -0800879 INIT_WORK(&sysrq->reinject_work, sysrq_reinject_alt_sysrq);
Dmitry Torokhov97f5f0c2010-03-21 22:31:26 -0700880
Dmitry Torokhovfcb71932010-11-15 00:23:42 -0800881 sysrq->handle.dev = dev;
882 sysrq->handle.handler = handler;
883 sysrq->handle.name = "sysrq";
884 sysrq->handle.private = sysrq;
Mathieu J. Poirier3d289512013-06-05 22:51:46 -0700885 setup_timer(&sysrq->keyreset_timer,
886 sysrq_do_reset, (unsigned long)sysrq);
Dmitry Torokhovfcb71932010-11-15 00:23:42 -0800887
888 error = input_register_handle(&sysrq->handle);
Dmitry Torokhov97f5f0c2010-03-21 22:31:26 -0700889 if (error) {
890 pr_err("Failed to register input sysrq handler, error %d\n",
891 error);
892 goto err_free;
893 }
894
Dmitry Torokhovfcb71932010-11-15 00:23:42 -0800895 error = input_open_device(&sysrq->handle);
Dmitry Torokhov97f5f0c2010-03-21 22:31:26 -0700896 if (error) {
897 pr_err("Failed to open input device, error %d\n", error);
898 goto err_unregister;
899 }
900
901 return 0;
902
903 err_unregister:
Dmitry Torokhovfcb71932010-11-15 00:23:42 -0800904 input_unregister_handle(&sysrq->handle);
Dmitry Torokhov97f5f0c2010-03-21 22:31:26 -0700905 err_free:
Dmitry Torokhovfcb71932010-11-15 00:23:42 -0800906 kfree(sysrq);
Dmitry Torokhov97f5f0c2010-03-21 22:31:26 -0700907 return error;
908}
909
910static void sysrq_disconnect(struct input_handle *handle)
911{
Dmitry Torokhovfcb71932010-11-15 00:23:42 -0800912 struct sysrq_state *sysrq = handle->private;
913
Dmitry Torokhov97f5f0c2010-03-21 22:31:26 -0700914 input_close_device(handle);
Dmitry Torokhovfcb71932010-11-15 00:23:42 -0800915 cancel_work_sync(&sysrq->reinject_work);
Mathieu J. Poirier39030782013-04-01 22:14:19 -0700916 del_timer_sync(&sysrq->keyreset_timer);
Dmitry Torokhov97f5f0c2010-03-21 22:31:26 -0700917 input_unregister_handle(handle);
Dmitry Torokhovfcb71932010-11-15 00:23:42 -0800918 kfree(sysrq);
Dmitry Torokhov97f5f0c2010-03-21 22:31:26 -0700919}
920
921/*
Dmitry Torokhov1966cb22010-09-29 18:04:21 -0700922 * We are matching on KEY_LEFTALT instead of KEY_SYSRQ because not all
923 * keyboards have SysRq key predefined and so user may add it to keymap
Dmitry Torokhov97f5f0c2010-03-21 22:31:26 -0700924 * later, but we expect all such keyboards to have left alt.
925 */
926static const struct input_device_id sysrq_ids[] = {
927 {
928 .flags = INPUT_DEVICE_ID_MATCH_EVBIT |
929 INPUT_DEVICE_ID_MATCH_KEYBIT,
930 .evbit = { BIT_MASK(EV_KEY) },
931 .keybit = { BIT_MASK(KEY_LEFTALT) },
932 },
933 { },
934};
935
936static struct input_handler sysrq_handler = {
937 .filter = sysrq_filter,
938 .connect = sysrq_connect,
939 .disconnect = sysrq_disconnect,
940 .name = "sysrq",
941 .id_table = sysrq_ids,
942};
943
944static bool sysrq_handler_registered;
945
946static inline void sysrq_register_handler(void)
947{
Mathieu Poirier154b7a42013-01-06 23:23:33 -0800948 unsigned short key;
Dmitry Torokhov97f5f0c2010-03-21 22:31:26 -0700949 int error;
Mathieu Poirier154b7a42013-01-06 23:23:33 -0800950 int i;
951
Mathieu J. Poirier4c076eb2013-08-03 17:22:08 -0700952 /* First check if a __weak interface was instantiated. */
Linus Torvaldsadf96e62013-02-27 09:59:50 -0800953 for (i = 0; i < ARRAY_SIZE(sysrq_reset_seq); i++) {
954 key = platform_sysrq_reset_seq[i];
955 if (key == KEY_RESERVED || key > KEY_MAX)
956 break;
Mathieu Poirier154b7a42013-01-06 23:23:33 -0800957
Linus Torvaldsadf96e62013-02-27 09:59:50 -0800958 sysrq_reset_seq[sysrq_reset_seq_len++] = key;
Mathieu Poirier154b7a42013-01-06 23:23:33 -0800959 }
Dmitry Torokhov97f5f0c2010-03-21 22:31:26 -0700960
Mathieu J. Poirier4c076eb2013-08-03 17:22:08 -0700961 /*
962 * DT configuration takes precedence over anything that would
963 * have been defined via the __weak interface.
964 */
965 sysrq_of_get_keyreset_config();
966
Dmitry Torokhov97f5f0c2010-03-21 22:31:26 -0700967 error = input_register_handler(&sysrq_handler);
968 if (error)
969 pr_err("Failed to register input handler, error %d", error);
970 else
971 sysrq_handler_registered = true;
972}
973
974static inline void sysrq_unregister_handler(void)
975{
976 if (sysrq_handler_registered) {
977 input_unregister_handler(&sysrq_handler);
978 sysrq_handler_registered = false;
979 }
980}
981
Mathieu Poirier154b7a42013-01-06 23:23:33 -0800982static int sysrq_reset_seq_param_set(const char *buffer,
983 const struct kernel_param *kp)
984{
985 unsigned long val;
986 int error;
987
Jingoo Han86b40562013-06-01 16:30:06 +0900988 error = kstrtoul(buffer, 0, &val);
Mathieu Poirier154b7a42013-01-06 23:23:33 -0800989 if (error < 0)
990 return error;
991
992 if (val > KEY_MAX)
993 return -EINVAL;
994
995 *((unsigned short *)kp->arg) = val;
996 sysrq_reset_seq_version++;
997
998 return 0;
999}
1000
1001static struct kernel_param_ops param_ops_sysrq_reset_seq = {
1002 .get = param_get_ushort,
1003 .set = sysrq_reset_seq_param_set,
1004};
1005
1006#define param_check_sysrq_reset_seq(name, p) \
1007 __param_check(name, p, unsigned short)
1008
1009module_param_array_named(reset_seq, sysrq_reset_seq, sysrq_reset_seq,
1010 &sysrq_reset_seq_len, 0644);
1011
Mathieu J. Poirier39030782013-04-01 22:14:19 -07001012module_param_named(sysrq_downtime_ms, sysrq_reset_downtime_ms, int, 0644);
1013
Dmitry Torokhov97f5f0c2010-03-21 22:31:26 -07001014#else
1015
1016static inline void sysrq_register_handler(void)
1017{
1018}
1019
1020static inline void sysrq_unregister_handler(void)
1021{
1022}
1023
1024#endif /* CONFIG_INPUT */
1025
1026int sysrq_toggle_support(int enable_mask)
1027{
1028 bool was_enabled = sysrq_on();
1029
1030 sysrq_enabled = enable_mask;
1031
1032 if (was_enabled != sysrq_on()) {
1033 if (sysrq_on())
1034 sysrq_register_handler();
1035 else
1036 sysrq_unregister_handler();
1037 }
1038
1039 return 0;
1040}
1041
Adrian Bunkcf62ddc2005-11-08 21:39:47 -08001042static int __sysrq_swap_key_ops(int key, struct sysrq_key_op *insert_op_p,
Andrew Mortonbf36b902006-03-25 03:07:08 -08001043 struct sysrq_key_op *remove_op_p)
1044{
Linus Torvalds1da177e2005-04-16 15:20:36 -07001045 int retval;
1046 unsigned long flags;
1047
1048 spin_lock_irqsave(&sysrq_key_table_lock, flags);
1049 if (__sysrq_get_key_op(key) == remove_op_p) {
1050 __sysrq_put_key_op(key, insert_op_p);
1051 retval = 0;
1052 } else {
1053 retval = -1;
1054 }
1055 spin_unlock_irqrestore(&sysrq_key_table_lock, flags);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001056 return retval;
1057}
1058
1059int register_sysrq_key(int key, struct sysrq_key_op *op_p)
1060{
1061 return __sysrq_swap_key_ops(key, op_p, NULL);
1062}
Andrew Mortonbf36b902006-03-25 03:07:08 -08001063EXPORT_SYMBOL(register_sysrq_key);
Linus Torvalds1da177e2005-04-16 15:20:36 -07001064
1065int unregister_sysrq_key(int key, struct sysrq_key_op *op_p)
1066{
1067 return __sysrq_swap_key_ops(key, NULL, op_p);
1068}
Linus Torvalds1da177e2005-04-16 15:20:36 -07001069EXPORT_SYMBOL(unregister_sysrq_key);
Alexey Dobriyanf40cbaa2008-10-15 22:04:23 -07001070
1071#ifdef CONFIG_PROC_FS
1072/*
1073 * writing 'C' to /proc/sysrq-trigger is like sysrq-C
1074 */
1075static ssize_t write_sysrq_trigger(struct file *file, const char __user *buf,
1076 size_t count, loff_t *ppos)
1077{
1078 if (count) {
1079 char c;
1080
1081 if (get_user(c, buf))
1082 return -EFAULT;
Dmitry Torokhovf3353972010-08-17 21:15:47 -07001083 __handle_sysrq(c, false);
Alexey Dobriyanf40cbaa2008-10-15 22:04:23 -07001084 }
Dmitry Torokhov97f5f0c2010-03-21 22:31:26 -07001085
Alexey Dobriyanf40cbaa2008-10-15 22:04:23 -07001086 return count;
1087}
1088
1089static const struct file_operations proc_sysrq_trigger_operations = {
1090 .write = write_sysrq_trigger,
Arnd Bergmann6038f372010-08-15 18:52:59 +02001091 .llseek = noop_llseek,
Alexey Dobriyanf40cbaa2008-10-15 22:04:23 -07001092};
1093
Dmitry Torokhov97f5f0c2010-03-21 22:31:26 -07001094static void sysrq_init_procfs(void)
1095{
1096 if (!proc_create("sysrq-trigger", S_IWUSR, NULL,
1097 &proc_sysrq_trigger_operations))
1098 pr_err("Failed to register proc interface\n");
1099}
1100
1101#else
1102
1103static inline void sysrq_init_procfs(void)
1104{
1105}
1106
1107#endif /* CONFIG_PROC_FS */
1108
Alexey Dobriyanf40cbaa2008-10-15 22:04:23 -07001109static int __init sysrq_init(void)
1110{
Dmitry Torokhov97f5f0c2010-03-21 22:31:26 -07001111 sysrq_init_procfs();
1112
1113 if (sysrq_on())
1114 sysrq_register_handler();
1115
Alexey Dobriyanf40cbaa2008-10-15 22:04:23 -07001116 return 0;
1117}
1118module_init(sysrq_init);