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Commit | Line | Data |
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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. | |
1da177e4 LT |
20 | */ |
21 | ||
27c766aa JP |
22 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
23 | ||
e65c5825 WS |
24 | #include <linux/init.h> |
25 | #include <linux/jiffies.h> | |
26 | #include <linux/kernel.h> | |
1da177e4 LT |
27 | #include <linux/module.h> |
28 | #include <linux/moduleparam.h> | |
e65c5825 | 29 | #include <linux/reboot.h> |
1da177e4 | 30 | #include <linux/timer.h> |
e65c5825 | 31 | #include <linux/types.h> |
1da177e4 | 32 | #include <linux/watchdog.h> |
1da177e4 | 33 | |
1da177e4 | 34 | #define TIMER_MARGIN 60 /* Default is 60 seconds */ |
a5132caf AC |
35 | static unsigned int soft_margin = TIMER_MARGIN; /* in seconds */ |
36 | module_param(soft_margin, uint, 0); | |
f92d3749 AC |
37 | MODULE_PARM_DESC(soft_margin, |
38 | "Watchdog soft_margin in seconds. (0 < soft_margin < 65536, default=" | |
39 | __MODULE_STRING(TIMER_MARGIN) ")"); | |
1da177e4 | 40 | |
86a1e189 WVS |
41 | static bool nowayout = WATCHDOG_NOWAYOUT; |
42 | module_param(nowayout, bool, 0); | |
f92d3749 AC |
43 | MODULE_PARM_DESC(nowayout, |
44 | "Watchdog cannot be stopped once started (default=" | |
45 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
1da177e4 | 46 | |
5f5e1909 | 47 | static int soft_noboot; |
1da177e4 | 48 | module_param(soft_noboot, int, 0); |
a77dba7e | 49 | MODULE_PARM_DESC(soft_noboot, |
a5132caf | 50 | "Softdog action, set to 1 to ignore reboots, 0 to reboot (default=0)"); |
1da177e4 | 51 | |
7fff4beb AJ |
52 | static int soft_panic; |
53 | module_param(soft_panic, int, 0); | |
54 | MODULE_PARM_DESC(soft_panic, | |
55 | "Softdog action, set to 1 to panic, 0 to reboot (default=0)"); | |
56 | ||
0efc70b8 | 57 | static void softdog_fire(unsigned long data) |
1da177e4 | 58 | { |
5889f06b | 59 | module_put(THIS_MODULE); |
4a23e2bf | 60 | if (soft_noboot) { |
27c766aa | 61 | pr_crit("Triggered - Reboot ignored\n"); |
4a23e2bf | 62 | } else if (soft_panic) { |
27c766aa JP |
63 | pr_crit("Initiating panic\n"); |
64 | panic("Software Watchdog Timer expired"); | |
7fff4beb | 65 | } else { |
27c766aa | 66 | pr_crit("Initiating system reboot\n"); |
479d0f41 | 67 | emergency_restart(); |
27c766aa | 68 | pr_crit("Reboot didn't ?????\n"); |
1da177e4 LT |
69 | } |
70 | } | |
71 | ||
44ba0f04 WS |
72 | static struct timer_list softdog_ticktock = |
73 | TIMER_INITIALIZER(softdog_fire, 0, 0); | |
74 | ||
2accf320 WS |
75 | static struct watchdog_device softdog_dev; |
76 | ||
77 | static void softdog_pretimeout(unsigned long data) | |
78 | { | |
79 | watchdog_notify_pretimeout(&softdog_dev); | |
80 | } | |
81 | ||
82 | static struct timer_list softdog_preticktock = | |
83 | TIMER_INITIALIZER(softdog_pretimeout, 0, 0); | |
84 | ||
a5132caf | 85 | static int softdog_ping(struct watchdog_device *w) |
1da177e4 | 86 | { |
4a23e2bf | 87 | if (!mod_timer(&softdog_ticktock, jiffies + (w->timeout * HZ))) |
5889f06b | 88 | __module_get(THIS_MODULE); |
2accf320 | 89 | |
4cbc6902 WS |
90 | if (IS_ENABLED(CONFIG_SOFT_WATCHDOG_PRETIMEOUT)) { |
91 | if (w->pretimeout) | |
92 | mod_timer(&softdog_preticktock, jiffies + | |
93 | (w->timeout - w->pretimeout) * HZ); | |
94 | else | |
95 | del_timer(&softdog_preticktock); | |
96 | } | |
2accf320 | 97 | |
1da177e4 LT |
98 | return 0; |
99 | } | |
100 | ||
a5132caf | 101 | static int softdog_stop(struct watchdog_device *w) |
1da177e4 | 102 | { |
0efc70b8 | 103 | if (del_timer(&softdog_ticktock)) |
5889f06b LR |
104 | module_put(THIS_MODULE); |
105 | ||
4cbc6902 WS |
106 | if (IS_ENABLED(CONFIG_SOFT_WATCHDOG_PRETIMEOUT)) |
107 | del_timer(&softdog_preticktock); | |
2accf320 | 108 | |
1da177e4 LT |
109 | return 0; |
110 | } | |
111 | ||
a5132caf AC |
112 | static struct watchdog_info softdog_info = { |
113 | .identity = "Software Watchdog", | |
4cbc6902 | 114 | .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, |
1da177e4 LT |
115 | }; |
116 | ||
85f15cfc | 117 | static const struct watchdog_ops softdog_ops = { |
a5132caf AC |
118 | .owner = THIS_MODULE, |
119 | .start = softdog_ping, | |
120 | .stop = softdog_stop, | |
a5132caf AC |
121 | }; |
122 | ||
123 | static struct watchdog_device softdog_dev = { | |
124 | .info = &softdog_info, | |
125 | .ops = &softdog_ops, | |
126 | .min_timeout = 1, | |
e8cf96ab WS |
127 | .max_timeout = 65535, |
128 | .timeout = TIMER_MARGIN, | |
1da177e4 LT |
129 | }; |
130 | ||
0efc70b8 | 131 | static int __init softdog_init(void) |
1da177e4 LT |
132 | { |
133 | int ret; | |
134 | ||
e8cf96ab | 135 | watchdog_init_timeout(&softdog_dev, soft_margin, NULL); |
a5132caf | 136 | watchdog_set_nowayout(&softdog_dev, nowayout); |
84ebcc17 | 137 | watchdog_stop_on_reboot(&softdog_dev); |
1da177e4 | 138 | |
4cbc6902 WS |
139 | if (IS_ENABLED(CONFIG_SOFT_WATCHDOG_PRETIMEOUT)) |
140 | softdog_info.options |= WDIOF_PRETIMEOUT; | |
141 | ||
a5132caf | 142 | ret = watchdog_register_device(&softdog_dev); |
84ebcc17 | 143 | if (ret) |
1da177e4 | 144 | return ret; |
1da177e4 | 145 | |
e8cf96ab WS |
146 | pr_info("initialized. soft_noboot=%d soft_margin=%d sec soft_panic=%d (nowayout=%d)\n", |
147 | soft_noboot, softdog_dev.timeout, soft_panic, nowayout); | |
1da177e4 LT |
148 | |
149 | return 0; | |
150 | } | |
0efc70b8 | 151 | module_init(softdog_init); |
1da177e4 | 152 | |
0efc70b8 | 153 | static void __exit softdog_exit(void) |
1da177e4 | 154 | { |
a5132caf | 155 | watchdog_unregister_device(&softdog_dev); |
1da177e4 | 156 | } |
0efc70b8 | 157 | module_exit(softdog_exit); |
1da177e4 LT |
158 | |
159 | MODULE_AUTHOR("Alan Cox"); | |
160 | MODULE_DESCRIPTION("Software Watchdog Device Driver"); | |
161 | MODULE_LICENSE("GPL"); |