Commit | Line | Data |
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d0173278 | 1 | // SPDX-License-Identifier: GPL-2.0+ |
1da177e4 | 2 | /* |
a5132caf | 3 | * SoftDog: A Software Watchdog Device |
1da177e4 | 4 | * |
143a2e54 WVS |
5 | * (c) Copyright 1996 Alan Cox <alan@lxorguk.ukuu.org.uk>, |
6 | * All Rights Reserved. | |
1da177e4 | 7 | * |
1da177e4 LT |
8 | * Neither Alan Cox nor CymruNet Ltd. admit liability nor provide |
9 | * warranty for any of this software. This material is provided | |
10 | * "AS-IS" and at no charge. | |
11 | * | |
12 | * (c) Copyright 1995 Alan Cox <alan@lxorguk.ukuu.org.uk> | |
13 | * | |
14 | * Software only watchdog driver. Unlike its big brother the WDT501P | |
15 | * driver this won't always recover a failed machine. | |
1da177e4 LT |
16 | */ |
17 | ||
27c766aa JP |
18 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
19 | ||
8d5755b3 | 20 | #include <linux/hrtimer.h> |
e65c5825 | 21 | #include <linux/init.h> |
e65c5825 | 22 | #include <linux/kernel.h> |
1da177e4 LT |
23 | #include <linux/module.h> |
24 | #include <linux/moduleparam.h> | |
e65c5825 | 25 | #include <linux/reboot.h> |
e65c5825 | 26 | #include <linux/types.h> |
1da177e4 | 27 | #include <linux/watchdog.h> |
1da177e4 | 28 | |
1da177e4 | 29 | #define TIMER_MARGIN 60 /* Default is 60 seconds */ |
a5132caf AC |
30 | static unsigned int soft_margin = TIMER_MARGIN; /* in seconds */ |
31 | module_param(soft_margin, uint, 0); | |
f92d3749 AC |
32 | MODULE_PARM_DESC(soft_margin, |
33 | "Watchdog soft_margin in seconds. (0 < soft_margin < 65536, default=" | |
34 | __MODULE_STRING(TIMER_MARGIN) ")"); | |
1da177e4 | 35 | |
86a1e189 WVS |
36 | static bool nowayout = WATCHDOG_NOWAYOUT; |
37 | module_param(nowayout, bool, 0); | |
f92d3749 AC |
38 | MODULE_PARM_DESC(nowayout, |
39 | "Watchdog cannot be stopped once started (default=" | |
40 | __MODULE_STRING(WATCHDOG_NOWAYOUT) ")"); | |
1da177e4 | 41 | |
5f5e1909 | 42 | static int soft_noboot; |
1da177e4 | 43 | module_param(soft_noboot, int, 0); |
a77dba7e | 44 | MODULE_PARM_DESC(soft_noboot, |
a5132caf | 45 | "Softdog action, set to 1 to ignore reboots, 0 to reboot (default=0)"); |
1da177e4 | 46 | |
7fff4beb AJ |
47 | static int soft_panic; |
48 | module_param(soft_panic, int, 0); | |
49 | MODULE_PARM_DESC(soft_panic, | |
50 | "Softdog action, set to 1 to panic, 0 to reboot (default=0)"); | |
51 | ||
8d5755b3 NC |
52 | static struct hrtimer softdog_ticktock; |
53 | static struct hrtimer softdog_preticktock; | |
54 | ||
55 | static enum hrtimer_restart softdog_fire(struct hrtimer *timer) | |
1da177e4 | 56 | { |
5889f06b | 57 | module_put(THIS_MODULE); |
4a23e2bf | 58 | if (soft_noboot) { |
27c766aa | 59 | pr_crit("Triggered - Reboot ignored\n"); |
4a23e2bf | 60 | } else if (soft_panic) { |
27c766aa JP |
61 | pr_crit("Initiating panic\n"); |
62 | panic("Software Watchdog Timer expired"); | |
7fff4beb | 63 | } else { |
27c766aa | 64 | pr_crit("Initiating system reboot\n"); |
479d0f41 | 65 | emergency_restart(); |
27c766aa | 66 | pr_crit("Reboot didn't ?????\n"); |
1da177e4 | 67 | } |
1da177e4 | 68 | |
8d5755b3 NC |
69 | return HRTIMER_NORESTART; |
70 | } | |
44ba0f04 | 71 | |
2accf320 WS |
72 | static struct watchdog_device softdog_dev; |
73 | ||
8d5755b3 | 74 | static enum hrtimer_restart softdog_pretimeout(struct hrtimer *timer) |
2accf320 WS |
75 | { |
76 | watchdog_notify_pretimeout(&softdog_dev); | |
2accf320 | 77 | |
8d5755b3 NC |
78 | return HRTIMER_NORESTART; |
79 | } | |
2accf320 | 80 | |
a5132caf | 81 | static int softdog_ping(struct watchdog_device *w) |
1da177e4 | 82 | { |
8d5755b3 | 83 | if (!hrtimer_active(&softdog_ticktock)) |
5889f06b | 84 | __module_get(THIS_MODULE); |
8d5755b3 NC |
85 | hrtimer_start(&softdog_ticktock, ktime_set(w->timeout, 0), |
86 | HRTIMER_MODE_REL); | |
2accf320 | 87 | |
4cbc6902 WS |
88 | if (IS_ENABLED(CONFIG_SOFT_WATCHDOG_PRETIMEOUT)) { |
89 | if (w->pretimeout) | |
8d5755b3 NC |
90 | hrtimer_start(&softdog_preticktock, |
91 | ktime_set(w->timeout - w->pretimeout, 0), | |
92 | HRTIMER_MODE_REL); | |
4cbc6902 | 93 | else |
8d5755b3 | 94 | hrtimer_cancel(&softdog_preticktock); |
4cbc6902 | 95 | } |
2accf320 | 96 | |
1da177e4 LT |
97 | return 0; |
98 | } | |
99 | ||
a5132caf | 100 | static int softdog_stop(struct watchdog_device *w) |
1da177e4 | 101 | { |
8d5755b3 | 102 | if (hrtimer_cancel(&softdog_ticktock)) |
5889f06b LR |
103 | module_put(THIS_MODULE); |
104 | ||
4cbc6902 | 105 | if (IS_ENABLED(CONFIG_SOFT_WATCHDOG_PRETIMEOUT)) |
8d5755b3 | 106 | hrtimer_cancel(&softdog_preticktock); |
2accf320 | 107 | |
1da177e4 LT |
108 | return 0; |
109 | } | |
110 | ||
a5132caf AC |
111 | static struct watchdog_info softdog_info = { |
112 | .identity = "Software Watchdog", | |
4cbc6902 | 113 | .options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, |
1da177e4 LT |
114 | }; |
115 | ||
85f15cfc | 116 | static const struct watchdog_ops softdog_ops = { |
a5132caf AC |
117 | .owner = THIS_MODULE, |
118 | .start = softdog_ping, | |
119 | .stop = softdog_stop, | |
a5132caf AC |
120 | }; |
121 | ||
122 | static struct watchdog_device softdog_dev = { | |
123 | .info = &softdog_info, | |
124 | .ops = &softdog_ops, | |
125 | .min_timeout = 1, | |
e8cf96ab WS |
126 | .max_timeout = 65535, |
127 | .timeout = TIMER_MARGIN, | |
1da177e4 LT |
128 | }; |
129 | ||
0efc70b8 | 130 | static int __init softdog_init(void) |
1da177e4 LT |
131 | { |
132 | int ret; | |
133 | ||
e8cf96ab | 134 | watchdog_init_timeout(&softdog_dev, soft_margin, NULL); |
a5132caf | 135 | watchdog_set_nowayout(&softdog_dev, nowayout); |
84ebcc17 | 136 | watchdog_stop_on_reboot(&softdog_dev); |
1da177e4 | 137 | |
8d5755b3 NC |
138 | hrtimer_init(&softdog_ticktock, CLOCK_MONOTONIC, HRTIMER_MODE_REL); |
139 | softdog_ticktock.function = softdog_fire; | |
140 | ||
141 | if (IS_ENABLED(CONFIG_SOFT_WATCHDOG_PRETIMEOUT)) { | |
4cbc6902 | 142 | softdog_info.options |= WDIOF_PRETIMEOUT; |
8d5755b3 NC |
143 | hrtimer_init(&softdog_preticktock, CLOCK_MONOTONIC, |
144 | HRTIMER_MODE_REL); | |
145 | softdog_preticktock.function = softdog_pretimeout; | |
146 | } | |
4cbc6902 | 147 | |
a5132caf | 148 | ret = watchdog_register_device(&softdog_dev); |
84ebcc17 | 149 | if (ret) |
1da177e4 | 150 | return ret; |
1da177e4 | 151 | |
e8cf96ab WS |
152 | pr_info("initialized. soft_noboot=%d soft_margin=%d sec soft_panic=%d (nowayout=%d)\n", |
153 | soft_noboot, softdog_dev.timeout, soft_panic, nowayout); | |
1da177e4 LT |
154 | |
155 | return 0; | |
156 | } | |
0efc70b8 | 157 | module_init(softdog_init); |
1da177e4 | 158 | |
0efc70b8 | 159 | static void __exit softdog_exit(void) |
1da177e4 | 160 | { |
a5132caf | 161 | watchdog_unregister_device(&softdog_dev); |
1da177e4 | 162 | } |
0efc70b8 | 163 | module_exit(softdog_exit); |
1da177e4 LT |
164 | |
165 | MODULE_AUTHOR("Alan Cox"); | |
166 | MODULE_DESCRIPTION("Software Watchdog Device Driver"); | |
167 | MODULE_LICENSE("GPL"); |