Commit | Line | Data |
---|---|---|
1da177e4 | 1 | /* |
a5132caf | 2 | * SoftDog: A Software Watchdog Device |
1da177e4 | 3 | * |
143a2e54 WVS |
4 | * (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>, |
5 | * All Rights Reserved. | |
1da177e4 LT |
6 | * |
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> | |
143a2e54 | 36 | * Added Matt Domsch's nowayout module option. |
1da177e4 LT |
37 | */ |
38 | ||
27c766aa JP |
39 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
40 | ||
1da177e4 LT |
41 | #include <linux/module.h> |
42 | #include <linux/moduleparam.h> | |
1da177e4 LT |
43 | #include <linux/types.h> |
44 | #include <linux/timer.h> | |
45 | #include <linux/miscdevice.h> | |
46 | #include <linux/watchdog.h> | |
1da177e4 LT |
47 | #include <linux/notifier.h> |
48 | #include <linux/reboot.h> | |
49 | #include <linux/init.h> | |
4e57b681 | 50 | #include <linux/jiffies.h> |
7fff4beb | 51 | #include <linux/kernel.h> |
1da177e4 | 52 | |
1da177e4 | 53 | #define TIMER_MARGIN 60 /* Default is 60 seconds */ |
a5132caf AC |
54 | static unsigned int soft_margin = TIMER_MARGIN; /* in seconds */ |
55 | module_param(soft_margin, uint, 0); | |
f92d3749 AC |
56 | MODULE_PARM_DESC(soft_margin, |
57 | "Watchdog soft_margin in seconds. (0 < soft_margin < 65536, default=" | |
58 | __MODULE_STRING(TIMER_MARGIN) ")"); | |
1da177e4 | 59 | |
86a1e189 WVS |
60 | static bool nowayout = WATCHDOG_NOWAYOUT; |
61 | module_param(nowayout, bool, 0); | |
f92d3749 AC |
62 | MODULE_PARM_DESC(nowayout, |
63 | "Watchdog cannot be stopped once started (default=" | |
64 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
1da177e4 | 65 | |
1da177e4 | 66 | static int soft_noboot = 0; |
1da177e4 | 67 | module_param(soft_noboot, int, 0); |
a77dba7e | 68 | MODULE_PARM_DESC(soft_noboot, |
a5132caf | 69 | "Softdog action, set to 1 to ignore reboots, 0 to reboot (default=0)"); |
1da177e4 | 70 | |
7fff4beb AJ |
71 | static int soft_panic; |
72 | module_param(soft_panic, int, 0); | |
73 | MODULE_PARM_DESC(soft_panic, | |
74 | "Softdog action, set to 1 to panic, 0 to reboot (default=0)"); | |
75 | ||
1da177e4 LT |
76 | /* |
77 | * Our timer | |
78 | */ | |
79 | ||
80 | static void watchdog_fire(unsigned long); | |
81 | ||
82 | static struct timer_list watchdog_ticktock = | |
83 | TIMER_INITIALIZER(watchdog_fire, 0, 0); | |
1da177e4 LT |
84 | |
85 | /* | |
86 | * If the timer expires.. | |
87 | */ | |
88 | ||
89 | static void watchdog_fire(unsigned long data) | |
90 | { | |
91 | if (soft_noboot) | |
27c766aa | 92 | pr_crit("Triggered - Reboot ignored\n"); |
7fff4beb | 93 | else if (soft_panic) { |
27c766aa JP |
94 | pr_crit("Initiating panic\n"); |
95 | panic("Software Watchdog Timer expired"); | |
7fff4beb | 96 | } else { |
27c766aa | 97 | pr_crit("Initiating system reboot\n"); |
479d0f41 | 98 | emergency_restart(); |
27c766aa | 99 | pr_crit("Reboot didn't ?????\n"); |
1da177e4 LT |
100 | } |
101 | } | |
102 | ||
103 | /* | |
104 | * Softdog operations | |
105 | */ | |
106 | ||
a5132caf | 107 | static int softdog_ping(struct watchdog_device *w) |
1da177e4 | 108 | { |
a5132caf | 109 | mod_timer(&watchdog_ticktock, jiffies+(w->timeout*HZ)); |
1da177e4 LT |
110 | return 0; |
111 | } | |
112 | ||
a5132caf | 113 | static int softdog_stop(struct watchdog_device *w) |
1da177e4 LT |
114 | { |
115 | del_timer(&watchdog_ticktock); | |
116 | return 0; | |
117 | } | |
118 | ||
a5132caf | 119 | static int softdog_set_timeout(struct watchdog_device *w, unsigned int t) |
1da177e4 | 120 | { |
a5132caf | 121 | w->timeout = t; |
1da177e4 LT |
122 | return 0; |
123 | } | |
124 | ||
1da177e4 LT |
125 | /* |
126 | * Notifier for system down | |
127 | */ | |
128 | ||
129 | static int softdog_notify_sys(struct notifier_block *this, unsigned long code, | |
130 | void *unused) | |
131 | { | |
f92d3749 | 132 | if (code == SYS_DOWN || code == SYS_HALT) |
1da177e4 | 133 | /* Turn the WDT off */ |
a5132caf | 134 | softdog_stop(NULL); |
1da177e4 LT |
135 | return NOTIFY_DONE; |
136 | } | |
137 | ||
138 | /* | |
139 | * Kernel Interfaces | |
140 | */ | |
141 | ||
a5132caf AC |
142 | static struct notifier_block softdog_notifier = { |
143 | .notifier_call = softdog_notify_sys, | |
1da177e4 LT |
144 | }; |
145 | ||
a5132caf AC |
146 | static struct watchdog_info softdog_info = { |
147 | .identity = "Software Watchdog", | |
148 | .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, | |
1da177e4 LT |
149 | }; |
150 | ||
a5132caf AC |
151 | static struct watchdog_ops softdog_ops = { |
152 | .owner = THIS_MODULE, | |
153 | .start = softdog_ping, | |
154 | .stop = softdog_stop, | |
a5132caf AC |
155 | .set_timeout = softdog_set_timeout, |
156 | }; | |
157 | ||
158 | static struct watchdog_device softdog_dev = { | |
159 | .info = &softdog_info, | |
160 | .ops = &softdog_ops, | |
161 | .min_timeout = 1, | |
162 | .max_timeout = 0xFFFF | |
1da177e4 LT |
163 | }; |
164 | ||
1da177e4 LT |
165 | static int __init watchdog_init(void) |
166 | { | |
167 | int ret; | |
168 | ||
f92d3749 AC |
169 | /* Check that the soft_margin value is within it's range; |
170 | if not reset to the default */ | |
a5132caf | 171 | if (soft_margin < 1 || soft_margin > 65535) { |
27c766aa | 172 | pr_info("soft_margin must be 0 < soft_margin < 65536, using %d\n", |
1da177e4 | 173 | TIMER_MARGIN); |
a5132caf | 174 | return -EINVAL; |
1da177e4 | 175 | } |
a5132caf AC |
176 | softdog_dev.timeout = soft_margin; |
177 | ||
178 | watchdog_set_nowayout(&softdog_dev, nowayout); | |
1da177e4 LT |
179 | |
180 | ret = register_reboot_notifier(&softdog_notifier); | |
181 | if (ret) { | |
27c766aa | 182 | pr_err("cannot register reboot notifier (err=%d)\n", ret); |
1da177e4 LT |
183 | return ret; |
184 | } | |
185 | ||
a5132caf | 186 | ret = watchdog_register_device(&softdog_dev); |
1da177e4 | 187 | if (ret) { |
1da177e4 LT |
188 | unregister_reboot_notifier(&softdog_notifier); |
189 | return ret; | |
190 | } | |
191 | ||
a5132caf | 192 | pr_info("Software Watchdog Timer: 0.08 initialized. soft_noboot=%d soft_margin=%d sec soft_panic=%d (nowayout=%d)\n", |
27c766aa | 193 | soft_noboot, soft_margin, soft_panic, nowayout); |
1da177e4 LT |
194 | |
195 | return 0; | |
196 | } | |
197 | ||
198 | static void __exit watchdog_exit(void) | |
199 | { | |
a5132caf | 200 | watchdog_unregister_device(&softdog_dev); |
1da177e4 LT |
201 | unregister_reboot_notifier(&softdog_notifier); |
202 | } | |
203 | ||
204 | module_init(watchdog_init); | |
205 | module_exit(watchdog_exit); | |
206 | ||
207 | MODULE_AUTHOR("Alan Cox"); | |
208 | MODULE_DESCRIPTION("Software Watchdog Device Driver"); | |
209 | MODULE_LICENSE("GPL"); | |
210 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); |