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