diff options
author | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
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committer | Linus Torvalds <torvalds@ppc970.osdl.org> | 2005-04-16 18:20:36 -0400 |
commit | 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch) | |
tree | 0bba044c4ce775e45a88a51686b5d9f90697ea9d /drivers/char/watchdog/softdog.c |
Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.
Let it rip!
Diffstat (limited to 'drivers/char/watchdog/softdog.c')
-rw-r--r-- | drivers/char/watchdog/softdog.c | 309 |
1 files changed, 309 insertions, 0 deletions
diff --git a/drivers/char/watchdog/softdog.c b/drivers/char/watchdog/softdog.c new file mode 100644 index 000000000000..117903498a01 --- /dev/null +++ b/drivers/char/watchdog/softdog.c | |||
@@ -0,0 +1,309 @@ | |||
1 | /* | ||
2 | * SoftDog 0.07: A Software Watchdog Device | ||
3 | * | ||
4 | * (c) Copyright 1996 Alan Cox <alan@redhat.com>, All Rights Reserved. | ||
5 | * http://www.redhat.com | ||
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> | ||
36 | * Added Matt Domsch's nowayout module option. | ||
37 | */ | ||
38 | |||
39 | #include <linux/module.h> | ||
40 | #include <linux/moduleparam.h> | ||
41 | #include <linux/config.h> | ||
42 | #include <linux/types.h> | ||
43 | #include <linux/timer.h> | ||
44 | #include <linux/miscdevice.h> | ||
45 | #include <linux/watchdog.h> | ||
46 | #include <linux/fs.h> | ||
47 | #include <linux/notifier.h> | ||
48 | #include <linux/reboot.h> | ||
49 | #include <linux/init.h> | ||
50 | #include <asm/uaccess.h> | ||
51 | |||
52 | #define PFX "SoftDog: " | ||
53 | |||
54 | #define TIMER_MARGIN 60 /* Default is 60 seconds */ | ||
55 | static int soft_margin = TIMER_MARGIN; /* in seconds */ | ||
56 | module_param(soft_margin, int, 0); | ||
57 | MODULE_PARM_DESC(soft_margin, "Watchdog soft_margin in seconds. (0<soft_margin<65536, default=" __MODULE_STRING(TIMER_MARGIN) ")"); | ||
58 | |||
59 | #ifdef CONFIG_WATCHDOG_NOWAYOUT | ||
60 | static int nowayout = 1; | ||
61 | #else | ||
62 | static int nowayout = 0; | ||
63 | #endif | ||
64 | |||
65 | module_param(nowayout, int, 0); | ||
66 | MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default=CONFIG_WATCHDOG_NOWAYOUT)"); | ||
67 | |||
68 | #ifdef ONLY_TESTING | ||
69 | static int soft_noboot = 1; | ||
70 | #else | ||
71 | static int soft_noboot = 0; | ||
72 | #endif /* ONLY_TESTING */ | ||
73 | |||
74 | module_param(soft_noboot, int, 0); | ||
75 | MODULE_PARM_DESC(soft_noboot, "Softdog action, set to 1 to ignore reboots, 0 to reboot (default depends on ONLY_TESTING)"); | ||
76 | |||
77 | /* | ||
78 | * Our timer | ||
79 | */ | ||
80 | |||
81 | static void watchdog_fire(unsigned long); | ||
82 | |||
83 | static struct timer_list watchdog_ticktock = | ||
84 | TIMER_INITIALIZER(watchdog_fire, 0, 0); | ||
85 | static unsigned long timer_alive; | ||
86 | static char expect_close; | ||
87 | |||
88 | |||
89 | /* | ||
90 | * If the timer expires.. | ||
91 | */ | ||
92 | |||
93 | static void watchdog_fire(unsigned long data) | ||
94 | { | ||
95 | if (soft_noboot) | ||
96 | printk(KERN_CRIT PFX "Triggered - Reboot ignored.\n"); | ||
97 | else | ||
98 | { | ||
99 | printk(KERN_CRIT PFX "Initiating system reboot.\n"); | ||
100 | machine_restart(NULL); | ||
101 | printk(KERN_CRIT PFX "Reboot didn't ?????\n"); | ||
102 | } | ||
103 | } | ||
104 | |||
105 | /* | ||
106 | * Softdog operations | ||
107 | */ | ||
108 | |||
109 | static int softdog_keepalive(void) | ||
110 | { | ||
111 | mod_timer(&watchdog_ticktock, jiffies+(soft_margin*HZ)); | ||
112 | return 0; | ||
113 | } | ||
114 | |||
115 | static int softdog_stop(void) | ||
116 | { | ||
117 | del_timer(&watchdog_ticktock); | ||
118 | return 0; | ||
119 | } | ||
120 | |||
121 | static int softdog_set_heartbeat(int t) | ||
122 | { | ||
123 | if ((t < 0x0001) || (t > 0xFFFF)) | ||
124 | return -EINVAL; | ||
125 | |||
126 | soft_margin = t; | ||
127 | return 0; | ||
128 | } | ||
129 | |||
130 | /* | ||
131 | * /dev/watchdog handling | ||
132 | */ | ||
133 | |||
134 | static int softdog_open(struct inode *inode, struct file *file) | ||
135 | { | ||
136 | if(test_and_set_bit(0, &timer_alive)) | ||
137 | return -EBUSY; | ||
138 | if (nowayout) | ||
139 | __module_get(THIS_MODULE); | ||
140 | /* | ||
141 | * Activate timer | ||
142 | */ | ||
143 | softdog_keepalive(); | ||
144 | return nonseekable_open(inode, file); | ||
145 | } | ||
146 | |||
147 | static int softdog_release(struct inode *inode, struct file *file) | ||
148 | { | ||
149 | /* | ||
150 | * Shut off the timer. | ||
151 | * Lock it in if it's a module and we set nowayout | ||
152 | */ | ||
153 | if (expect_close == 42) { | ||
154 | softdog_stop(); | ||
155 | } else { | ||
156 | printk(KERN_CRIT PFX "Unexpected close, not stopping watchdog!\n"); | ||
157 | softdog_keepalive(); | ||
158 | } | ||
159 | clear_bit(0, &timer_alive); | ||
160 | expect_close = 0; | ||
161 | return 0; | ||
162 | } | ||
163 | |||
164 | static ssize_t softdog_write(struct file *file, const char __user *data, size_t len, loff_t *ppos) | ||
165 | { | ||
166 | /* | ||
167 | * Refresh the timer. | ||
168 | */ | ||
169 | if(len) { | ||
170 | if (!nowayout) { | ||
171 | size_t i; | ||
172 | |||
173 | /* In case it was set long ago */ | ||
174 | expect_close = 0; | ||
175 | |||
176 | for (i = 0; i != len; i++) { | ||
177 | char c; | ||
178 | |||
179 | if (get_user(c, data + i)) | ||
180 | return -EFAULT; | ||
181 | if (c == 'V') | ||
182 | expect_close = 42; | ||
183 | } | ||
184 | } | ||
185 | softdog_keepalive(); | ||
186 | } | ||
187 | return len; | ||
188 | } | ||
189 | |||
190 | static int softdog_ioctl(struct inode *inode, struct file *file, | ||
191 | unsigned int cmd, unsigned long arg) | ||
192 | { | ||
193 | void __user *argp = (void __user *)arg; | ||
194 | int __user *p = argp; | ||
195 | int new_margin; | ||
196 | static struct watchdog_info ident = { | ||
197 | .options = WDIOF_SETTIMEOUT | | ||
198 | WDIOF_KEEPALIVEPING | | ||
199 | WDIOF_MAGICCLOSE, | ||
200 | .firmware_version = 0, | ||
201 | .identity = "Software Watchdog", | ||
202 | }; | ||
203 | switch (cmd) { | ||
204 | default: | ||
205 | return -ENOIOCTLCMD; | ||
206 | case WDIOC_GETSUPPORT: | ||
207 | return copy_to_user(argp, &ident, | ||
208 | sizeof(ident)) ? -EFAULT : 0; | ||
209 | case WDIOC_GETSTATUS: | ||
210 | case WDIOC_GETBOOTSTATUS: | ||
211 | return put_user(0, p); | ||
212 | case WDIOC_KEEPALIVE: | ||
213 | softdog_keepalive(); | ||
214 | return 0; | ||
215 | case WDIOC_SETTIMEOUT: | ||
216 | if (get_user(new_margin, p)) | ||
217 | return -EFAULT; | ||
218 | if (softdog_set_heartbeat(new_margin)) | ||
219 | return -EINVAL; | ||
220 | softdog_keepalive(); | ||
221 | /* Fall */ | ||
222 | case WDIOC_GETTIMEOUT: | ||
223 | return put_user(soft_margin, p); | ||
224 | } | ||
225 | } | ||
226 | |||
227 | /* | ||
228 | * Notifier for system down | ||
229 | */ | ||
230 | |||
231 | static int softdog_notify_sys(struct notifier_block *this, unsigned long code, | ||
232 | void *unused) | ||
233 | { | ||
234 | if(code==SYS_DOWN || code==SYS_HALT) { | ||
235 | /* Turn the WDT off */ | ||
236 | softdog_stop(); | ||
237 | } | ||
238 | return NOTIFY_DONE; | ||
239 | } | ||
240 | |||
241 | /* | ||
242 | * Kernel Interfaces | ||
243 | */ | ||
244 | |||
245 | static struct file_operations softdog_fops = { | ||
246 | .owner = THIS_MODULE, | ||
247 | .llseek = no_llseek, | ||
248 | .write = softdog_write, | ||
249 | .ioctl = softdog_ioctl, | ||
250 | .open = softdog_open, | ||
251 | .release = softdog_release, | ||
252 | }; | ||
253 | |||
254 | static struct miscdevice softdog_miscdev = { | ||
255 | .minor = WATCHDOG_MINOR, | ||
256 | .name = "watchdog", | ||
257 | .fops = &softdog_fops, | ||
258 | }; | ||
259 | |||
260 | static struct notifier_block softdog_notifier = { | ||
261 | .notifier_call = softdog_notify_sys, | ||
262 | }; | ||
263 | |||
264 | static char banner[] __initdata = KERN_INFO "Software Watchdog Timer: 0.07 initialized. soft_noboot=%d soft_margin=%d sec (nowayout= %d)\n"; | ||
265 | |||
266 | static int __init watchdog_init(void) | ||
267 | { | ||
268 | int ret; | ||
269 | |||
270 | /* Check that the soft_margin value is within it's range ; if not reset to the default */ | ||
271 | if (softdog_set_heartbeat(soft_margin)) { | ||
272 | softdog_set_heartbeat(TIMER_MARGIN); | ||
273 | printk(KERN_INFO PFX "soft_margin value must be 0<soft_margin<65536, using %d\n", | ||
274 | TIMER_MARGIN); | ||
275 | } | ||
276 | |||
277 | ret = register_reboot_notifier(&softdog_notifier); | ||
278 | if (ret) { | ||
279 | printk (KERN_ERR PFX "cannot register reboot notifier (err=%d)\n", | ||
280 | ret); | ||
281 | return ret; | ||
282 | } | ||
283 | |||
284 | ret = misc_register(&softdog_miscdev); | ||
285 | if (ret) { | ||
286 | printk (KERN_ERR PFX "cannot register miscdev on minor=%d (err=%d)\n", | ||
287 | WATCHDOG_MINOR, ret); | ||
288 | unregister_reboot_notifier(&softdog_notifier); | ||
289 | return ret; | ||
290 | } | ||
291 | |||
292 | printk(banner, soft_noboot, soft_margin, nowayout); | ||
293 | |||
294 | return 0; | ||
295 | } | ||
296 | |||
297 | static void __exit watchdog_exit(void) | ||
298 | { | ||
299 | misc_deregister(&softdog_miscdev); | ||
300 | unregister_reboot_notifier(&softdog_notifier); | ||
301 | } | ||
302 | |||
303 | module_init(watchdog_init); | ||
304 | module_exit(watchdog_exit); | ||
305 | |||
306 | MODULE_AUTHOR("Alan Cox"); | ||
307 | MODULE_DESCRIPTION("Software Watchdog Device Driver"); | ||
308 | MODULE_LICENSE("GPL"); | ||
309 | MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR); | ||