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> | |
1da177e4 | 45 | #include <linux/watchdog.h> |
1da177e4 LT |
46 | #include <linux/notifier.h> |
47 | #include <linux/reboot.h> | |
48 | #include <linux/init.h> | |
4e57b681 | 49 | #include <linux/jiffies.h> |
7fff4beb | 50 | #include <linux/kernel.h> |
1da177e4 | 51 | |
1da177e4 | 52 | #define TIMER_MARGIN 60 /* Default is 60 seconds */ |
a5132caf AC |
53 | static unsigned int soft_margin = TIMER_MARGIN; /* in seconds */ |
54 | module_param(soft_margin, uint, 0); | |
f92d3749 AC |
55 | MODULE_PARM_DESC(soft_margin, |
56 | "Watchdog soft_margin in seconds. (0 < soft_margin < 65536, default=" | |
57 | __MODULE_STRING(TIMER_MARGIN) ")"); | |
1da177e4 | 58 | |
86a1e189 WVS |
59 | static bool nowayout = WATCHDOG_NOWAYOUT; |
60 | module_param(nowayout, bool, 0); | |
f92d3749 AC |
61 | MODULE_PARM_DESC(nowayout, |
62 | "Watchdog cannot be stopped once started (default=" | |
63 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
1da177e4 | 64 | |
5f5e1909 | 65 | static int soft_noboot; |
1da177e4 | 66 | module_param(soft_noboot, int, 0); |
a77dba7e | 67 | MODULE_PARM_DESC(soft_noboot, |
a5132caf | 68 | "Softdog action, set to 1 to ignore reboots, 0 to reboot (default=0)"); |
1da177e4 | 69 | |
7fff4beb AJ |
70 | static int soft_panic; |
71 | module_param(soft_panic, int, 0); | |
72 | MODULE_PARM_DESC(soft_panic, | |
73 | "Softdog action, set to 1 to panic, 0 to reboot (default=0)"); | |
74 | ||
1da177e4 LT |
75 | /* |
76 | * Our timer | |
77 | */ | |
78 | ||
79 | static void watchdog_fire(unsigned long); | |
80 | ||
81 | static struct timer_list watchdog_ticktock = | |
82 | TIMER_INITIALIZER(watchdog_fire, 0, 0); | |
1da177e4 LT |
83 | |
84 | /* | |
85 | * If the timer expires.. | |
86 | */ | |
87 | ||
88 | static void watchdog_fire(unsigned long data) | |
89 | { | |
90 | if (soft_noboot) | |
27c766aa | 91 | pr_crit("Triggered - Reboot ignored\n"); |
7fff4beb | 92 | else if (soft_panic) { |
27c766aa JP |
93 | pr_crit("Initiating panic\n"); |
94 | panic("Software Watchdog Timer expired"); | |
7fff4beb | 95 | } else { |
27c766aa | 96 | pr_crit("Initiating system reboot\n"); |
479d0f41 | 97 | emergency_restart(); |
27c766aa | 98 | pr_crit("Reboot didn't ?????\n"); |
1da177e4 LT |
99 | } |
100 | } | |
101 | ||
102 | /* | |
103 | * Softdog operations | |
104 | */ | |
105 | ||
a5132caf | 106 | static int softdog_ping(struct watchdog_device *w) |
1da177e4 | 107 | { |
a5132caf | 108 | mod_timer(&watchdog_ticktock, jiffies+(w->timeout*HZ)); |
1da177e4 LT |
109 | return 0; |
110 | } | |
111 | ||
a5132caf | 112 | static int softdog_stop(struct watchdog_device *w) |
1da177e4 LT |
113 | { |
114 | del_timer(&watchdog_ticktock); | |
115 | return 0; | |
116 | } | |
117 | ||
a5132caf | 118 | static int softdog_set_timeout(struct watchdog_device *w, unsigned int t) |
1da177e4 | 119 | { |
a5132caf | 120 | w->timeout = t; |
1da177e4 LT |
121 | return 0; |
122 | } | |
123 | ||
1da177e4 LT |
124 | /* |
125 | * Notifier for system down | |
126 | */ | |
127 | ||
128 | static int softdog_notify_sys(struct notifier_block *this, unsigned long code, | |
129 | void *unused) | |
130 | { | |
f92d3749 | 131 | if (code == SYS_DOWN || code == SYS_HALT) |
1da177e4 | 132 | /* Turn the WDT off */ |
a5132caf | 133 | softdog_stop(NULL); |
1da177e4 LT |
134 | return NOTIFY_DONE; |
135 | } | |
136 | ||
137 | /* | |
138 | * Kernel Interfaces | |
139 | */ | |
140 | ||
a5132caf AC |
141 | static struct notifier_block softdog_notifier = { |
142 | .notifier_call = softdog_notify_sys, | |
1da177e4 LT |
143 | }; |
144 | ||
a5132caf AC |
145 | static struct watchdog_info softdog_info = { |
146 | .identity = "Software Watchdog", | |
147 | .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, | |
1da177e4 LT |
148 | }; |
149 | ||
a5132caf AC |
150 | static struct watchdog_ops softdog_ops = { |
151 | .owner = THIS_MODULE, | |
152 | .start = softdog_ping, | |
153 | .stop = softdog_stop, | |
a5132caf AC |
154 | .set_timeout = softdog_set_timeout, |
155 | }; | |
156 | ||
157 | static struct watchdog_device softdog_dev = { | |
158 | .info = &softdog_info, | |
159 | .ops = &softdog_ops, | |
160 | .min_timeout = 1, | |
161 | .max_timeout = 0xFFFF | |
1da177e4 LT |
162 | }; |
163 | ||
1da177e4 LT |
164 | static int __init watchdog_init(void) |
165 | { | |
166 | int ret; | |
167 | ||
f92d3749 AC |
168 | /* Check that the soft_margin value is within it's range; |
169 | if not reset to the default */ | |
a5132caf | 170 | if (soft_margin < 1 || soft_margin > 65535) { |
27c766aa | 171 | pr_info("soft_margin must be 0 < soft_margin < 65536, using %d\n", |
1da177e4 | 172 | TIMER_MARGIN); |
a5132caf | 173 | return -EINVAL; |
1da177e4 | 174 | } |
a5132caf AC |
175 | softdog_dev.timeout = soft_margin; |
176 | ||
177 | watchdog_set_nowayout(&softdog_dev, nowayout); | |
1da177e4 LT |
178 | |
179 | ret = register_reboot_notifier(&softdog_notifier); | |
180 | if (ret) { | |
27c766aa | 181 | pr_err("cannot register reboot notifier (err=%d)\n", ret); |
1da177e4 LT |
182 | return ret; |
183 | } | |
184 | ||
a5132caf | 185 | ret = watchdog_register_device(&softdog_dev); |
1da177e4 | 186 | if (ret) { |
1da177e4 LT |
187 | unregister_reboot_notifier(&softdog_notifier); |
188 | return ret; | |
189 | } | |
190 | ||
a5132caf | 191 | pr_info("Software Watchdog Timer: 0.08 initialized. soft_noboot=%d soft_margin=%d sec soft_panic=%d (nowayout=%d)\n", |
27c766aa | 192 | soft_noboot, soft_margin, soft_panic, nowayout); |
1da177e4 LT |
193 | |
194 | return 0; | |
195 | } | |
196 | ||
197 | static void __exit watchdog_exit(void) | |
198 | { | |
a5132caf | 199 | watchdog_unregister_device(&softdog_dev); |
1da177e4 LT |
200 | unregister_reboot_notifier(&softdog_notifier); |
201 | } | |
202 | ||
203 | module_init(watchdog_init); | |
204 | module_exit(watchdog_exit); | |
205 | ||
206 | MODULE_AUTHOR("Alan Cox"); | |
207 | MODULE_DESCRIPTION("Software Watchdog Device Driver"); | |
208 | MODULE_LICENSE("GPL"); |