blob: c04a1aa158e25762fcbe2b161052beaf56897d7f [file] [log] [blame]
Linus Torvalds1da177e2005-04-16 15:20:36 -07001/*
Alan Coxa5132ca2012-02-28 22:48:11 +00002 * SoftDog: A Software Watchdog Device
Linus Torvalds1da177e2005-04-16 15:20:36 -07003 *
Wim Van Sebroeck143a2e52009-03-18 08:35:09 +00004 * (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>,
5 * All Rights Reserved.
Linus Torvalds1da177e2005-04-16 15:20:36 -07006 *
7 * This program is free software; you can redistribute it and/or
8 * modify it under the terms of the GNU General Public License
9 * as published by the Free Software Foundation; either version
10 * 2 of the License, or (at your option) any later version.
11 *
12 * Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
13 * warranty for any of this software. This material is provided
14 * "AS-IS" and at no charge.
15 *
16 * (c) Copyright 1995 Alan Cox <alan@lxorguk.ukuu.org.uk>
17 *
18 * Software only watchdog driver. Unlike its big brother the WDT501P
19 * driver this won't always recover a failed machine.
20 *
21 * 03/96: Angelo Haritsis <ah@doc.ic.ac.uk> :
22 * Modularised.
23 * Added soft_margin; use upon insmod to change the timer delay.
24 * NB: uses same minor as wdt (WATCHDOG_MINOR); we could use separate
25 * minors.
26 *
27 * 19980911 Alan Cox
28 * Made SMP safe for 2.3.x
29 *
30 * 20011127 Joel Becker (jlbec@evilplan.org>
31 * Added soft_noboot; Allows testing the softdog trigger without
32 * requiring a recompile.
33 * Added WDIOC_GETTIMEOUT and WDIOC_SETTIMOUT.
34 *
35 * 20020530 Joel Becker <joel.becker@oracle.com>
Wim Van Sebroeck143a2e52009-03-18 08:35:09 +000036 * Added Matt Domsch's nowayout module option.
Linus Torvalds1da177e2005-04-16 15:20:36 -070037 */
38
Joe Perches27c766a2012-02-15 15:06:19 -080039#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
40
Linus Torvalds1da177e2005-04-16 15:20:36 -070041#include <linux/module.h>
42#include <linux/moduleparam.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070043#include <linux/types.h>
44#include <linux/timer.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070045#include <linux/watchdog.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070046#include <linux/notifier.h>
47#include <linux/reboot.h>
48#include <linux/init.h>
Tim Schmielau4e57b682005-10-30 15:03:48 -080049#include <linux/jiffies.h>
Anithra P Janakiraman7fff4be2011-03-28 14:29:19 -070050#include <linux/kernel.h>
Linus Torvalds1da177e2005-04-16 15:20:36 -070051
Linus Torvalds1da177e2005-04-16 15:20:36 -070052#define TIMER_MARGIN 60 /* Default is 60 seconds */
Alan Coxa5132ca2012-02-28 22:48:11 +000053static unsigned int soft_margin = TIMER_MARGIN; /* in seconds */
54module_param(soft_margin, uint, 0);
Alan Coxf92d3742008-05-19 14:09:06 +010055MODULE_PARM_DESC(soft_margin,
56 "Watchdog soft_margin in seconds. (0 < soft_margin < 65536, default="
57 __MODULE_STRING(TIMER_MARGIN) ")");
Linus Torvalds1da177e2005-04-16 15:20:36 -070058
Wim Van Sebroeck86a1e182012-03-05 16:51:11 +010059static bool nowayout = WATCHDOG_NOWAYOUT;
60module_param(nowayout, bool, 0);
Alan Coxf92d3742008-05-19 14:09:06 +010061MODULE_PARM_DESC(nowayout,
62 "Watchdog cannot be stopped once started (default="
63 __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
Linus Torvalds1da177e2005-04-16 15:20:36 -070064
Linus Torvalds1da177e2005-04-16 15:20:36 -070065static int soft_noboot = 0;
Linus Torvalds1da177e2005-04-16 15:20:36 -070066module_param(soft_noboot, int, 0);
Wim Van Sebroecka77dba72009-04-14 20:20:07 +000067MODULE_PARM_DESC(soft_noboot,
Alan Coxa5132ca2012-02-28 22:48:11 +000068 "Softdog action, set to 1 to ignore reboots, 0 to reboot (default=0)");
Linus Torvalds1da177e2005-04-16 15:20:36 -070069
Anithra P Janakiraman7fff4be2011-03-28 14:29:19 -070070static int soft_panic;
71module_param(soft_panic, int, 0);
72MODULE_PARM_DESC(soft_panic,
73 "Softdog action, set to 1 to panic, 0 to reboot (default=0)");
74
Linus Torvalds1da177e2005-04-16 15:20:36 -070075/*
76 * Our timer
77 */
78
79static void watchdog_fire(unsigned long);
80
81static struct timer_list watchdog_ticktock =
82 TIMER_INITIALIZER(watchdog_fire, 0, 0);
Linus Torvalds1da177e2005-04-16 15:20:36 -070083
84/*
85 * If the timer expires..
86 */
87
88static void watchdog_fire(unsigned long data)
89{
90 if (soft_noboot)
Joe Perches27c766a2012-02-15 15:06:19 -080091 pr_crit("Triggered - Reboot ignored\n");
Anithra P Janakiraman7fff4be2011-03-28 14:29:19 -070092 else if (soft_panic) {
Joe Perches27c766a2012-02-15 15:06:19 -080093 pr_crit("Initiating panic\n");
94 panic("Software Watchdog Timer expired");
Anithra P Janakiraman7fff4be2011-03-28 14:29:19 -070095 } else {
Joe Perches27c766a2012-02-15 15:06:19 -080096 pr_crit("Initiating system reboot\n");
Andrew Morton479d0f42005-07-26 21:41:38 -070097 emergency_restart();
Joe Perches27c766a2012-02-15 15:06:19 -080098 pr_crit("Reboot didn't ?????\n");
Linus Torvalds1da177e2005-04-16 15:20:36 -070099 }
100}
101
102/*
103 * Softdog operations
104 */
105
Alan Coxa5132ca2012-02-28 22:48:11 +0000106static int softdog_ping(struct watchdog_device *w)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700107{
Alan Coxa5132ca2012-02-28 22:48:11 +0000108 mod_timer(&watchdog_ticktock, jiffies+(w->timeout*HZ));
Linus Torvalds1da177e2005-04-16 15:20:36 -0700109 return 0;
110}
111
Alan Coxa5132ca2012-02-28 22:48:11 +0000112static int softdog_stop(struct watchdog_device *w)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700113{
114 del_timer(&watchdog_ticktock);
115 return 0;
116}
117
Alan Coxa5132ca2012-02-28 22:48:11 +0000118static int softdog_set_timeout(struct watchdog_device *w, unsigned int t)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700119{
Alan Coxa5132ca2012-02-28 22:48:11 +0000120 w->timeout = t;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700121 return 0;
122}
123
124/*
Linus Torvalds1da177e2005-04-16 15:20:36 -0700125 * Notifier for system down
126 */
127
128static int softdog_notify_sys(struct notifier_block *this, unsigned long code,
129 void *unused)
130{
Alan Coxf92d3742008-05-19 14:09:06 +0100131 if (code == SYS_DOWN || code == SYS_HALT)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700132 /* Turn the WDT off */
Alan Coxa5132ca2012-02-28 22:48:11 +0000133 softdog_stop(NULL);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700134 return NOTIFY_DONE;
135}
136
137/*
138 * Kernel Interfaces
139 */
140
Linus Torvalds1da177e2005-04-16 15:20:36 -0700141static struct notifier_block softdog_notifier = {
142 .notifier_call = softdog_notify_sys,
143};
144
Alan Coxa5132ca2012-02-28 22:48:11 +0000145static struct watchdog_info softdog_info = {
146 .identity = "Software Watchdog",
147 .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE,
148};
149
150static struct watchdog_ops softdog_ops = {
151 .owner = THIS_MODULE,
152 .start = softdog_ping,
153 .stop = softdog_stop,
Alan Coxa5132ca2012-02-28 22:48:11 +0000154 .set_timeout = softdog_set_timeout,
155};
156
157static struct watchdog_device softdog_dev = {
158 .info = &softdog_info,
159 .ops = &softdog_ops,
160 .min_timeout = 1,
161 .max_timeout = 0xFFFF
162};
163
Linus Torvalds1da177e2005-04-16 15:20:36 -0700164static int __init watchdog_init(void)
165{
166 int ret;
167
Alan Coxf92d3742008-05-19 14:09:06 +0100168 /* Check that the soft_margin value is within it's range;
169 if not reset to the default */
Alan Coxa5132ca2012-02-28 22:48:11 +0000170 if (soft_margin < 1 || soft_margin > 65535) {
Joe Perches27c766a2012-02-15 15:06:19 -0800171 pr_info("soft_margin must be 0 < soft_margin < 65536, using %d\n",
Linus Torvalds1da177e2005-04-16 15:20:36 -0700172 TIMER_MARGIN);
Alan Coxa5132ca2012-02-28 22:48:11 +0000173 return -EINVAL;
Linus Torvalds1da177e2005-04-16 15:20:36 -0700174 }
Alan Coxa5132ca2012-02-28 22:48:11 +0000175 softdog_dev.timeout = soft_margin;
176
177 watchdog_set_nowayout(&softdog_dev, nowayout);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700178
179 ret = register_reboot_notifier(&softdog_notifier);
180 if (ret) {
Joe Perches27c766a2012-02-15 15:06:19 -0800181 pr_err("cannot register reboot notifier (err=%d)\n", ret);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700182 return ret;
183 }
184
Alan Coxa5132ca2012-02-28 22:48:11 +0000185 ret = watchdog_register_device(&softdog_dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700186 if (ret) {
Linus Torvalds1da177e2005-04-16 15:20:36 -0700187 unregister_reboot_notifier(&softdog_notifier);
188 return ret;
189 }
190
Alan Coxa5132ca2012-02-28 22:48:11 +0000191 pr_info("Software Watchdog Timer: 0.08 initialized. soft_noboot=%d soft_margin=%d sec soft_panic=%d (nowayout=%d)\n",
Joe Perches27c766a2012-02-15 15:06:19 -0800192 soft_noboot, soft_margin, soft_panic, nowayout);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700193
194 return 0;
195}
196
197static void __exit watchdog_exit(void)
198{
Alan Coxa5132ca2012-02-28 22:48:11 +0000199 watchdog_unregister_device(&softdog_dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700200 unregister_reboot_notifier(&softdog_notifier);
201}
202
203module_init(watchdog_init);
204module_exit(watchdog_exit);
205
206MODULE_AUTHOR("Alan Cox");
207MODULE_DESCRIPTION("Software Watchdog Device Driver");
208MODULE_LICENSE("GPL");