Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | /* UML hardware watchdog, shamelessly stolen from: |
| 2 | * |
| 3 | * SoftDog 0.05: A Software Watchdog Device |
| 4 | * |
| 5 | * (c) Copyright 1996 Alan Cox <alan@redhat.com>, All Rights Reserved. |
| 6 | * http://www.redhat.com |
| 7 | * |
| 8 | * This program is free software; you can redistribute it and/or |
| 9 | * modify it under the terms of the GNU General Public License |
| 10 | * as published by the Free Software Foundation; either version |
| 11 | * 2 of the License, or (at your option) any later version. |
Jeff Dike | 5bbcbec | 2007-02-10 01:43:58 -0800 | [diff] [blame] | 12 | * |
| 13 | * Neither Alan Cox nor CymruNet Ltd. admit liability nor provide |
| 14 | * warranty for any of this software. This material is provided |
| 15 | * "AS-IS" and at no charge. |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 16 | * |
| 17 | * (c) Copyright 1995 Alan Cox <alan@lxorguk.ukuu.org.uk> |
| 18 | * |
| 19 | * Software only watchdog driver. Unlike its big brother the WDT501P |
| 20 | * driver this won't always recover a failed machine. |
| 21 | * |
| 22 | * 03/96: Angelo Haritsis <ah@doc.ic.ac.uk> : |
| 23 | * Modularised. |
| 24 | * Added soft_margin; use upon insmod to change the timer delay. |
| 25 | * NB: uses same minor as wdt (WATCHDOG_MINOR); we could use separate |
| 26 | * minors. |
| 27 | * |
| 28 | * 19980911 Alan Cox |
| 29 | * Made SMP safe for 2.3.x |
| 30 | * |
| 31 | * 20011127 Joel Becker (jlbec@evilplan.org> |
Jeff Dike | 5bbcbec | 2007-02-10 01:43:58 -0800 | [diff] [blame] | 32 | * Added soft_noboot; Allows testing the softdog trigger without |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 33 | * requiring a recompile. |
| 34 | * Added WDIOC_GETTIMEOUT and WDIOC_SETTIMOUT. |
| 35 | */ |
Jeff Dike | 5bbcbec | 2007-02-10 01:43:58 -0800 | [diff] [blame] | 36 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 37 | #include <linux/module.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 38 | #include <linux/types.h> |
| 39 | #include <linux/kernel.h> |
| 40 | #include <linux/fs.h> |
| 41 | #include <linux/mm.h> |
| 42 | #include <linux/miscdevice.h> |
| 43 | #include <linux/watchdog.h> |
| 44 | #include <linux/reboot.h> |
| 45 | #include <linux/smp_lock.h> |
| 46 | #include <linux/init.h> |
Jeff Dike | 42d3611 | 2007-02-10 01:43:57 -0800 | [diff] [blame] | 47 | #include <linux/spinlock.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 48 | #include <asm/uaccess.h> |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 49 | #include "mconsole.h" |
| 50 | |
| 51 | MODULE_LICENSE("GPL"); |
| 52 | |
Jeff Dike | 42d3611 | 2007-02-10 01:43:57 -0800 | [diff] [blame] | 53 | static DEFINE_SPINLOCK(lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 54 | static int timer_alive; |
| 55 | static int harddog_in_fd = -1; |
| 56 | static int harddog_out_fd = -1; |
| 57 | |
| 58 | /* |
| 59 | * Allow only one person to hold it open |
| 60 | */ |
Jeff Dike | 5bbcbec | 2007-02-10 01:43:58 -0800 | [diff] [blame] | 61 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 62 | extern int start_watchdog(int *in_fd_ret, int *out_fd_ret, char *sock); |
| 63 | |
| 64 | static int harddog_open(struct inode *inode, struct file *file) |
| 65 | { |
Jeff Dike | 42d3611 | 2007-02-10 01:43:57 -0800 | [diff] [blame] | 66 | int err = -EBUSY; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 67 | char *sock = NULL; |
| 68 | |
Jeff Dike | 42d3611 | 2007-02-10 01:43:57 -0800 | [diff] [blame] | 69 | spin_lock(&lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 70 | if(timer_alive) |
Jeff Dike | 42d3611 | 2007-02-10 01:43:57 -0800 | [diff] [blame] | 71 | goto err; |
Jeff Dike | 5bbcbec | 2007-02-10 01:43:58 -0800 | [diff] [blame] | 72 | #ifdef CONFIG_HARDDOG_NOWAYOUT |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 73 | __module_get(THIS_MODULE); |
| 74 | #endif |
| 75 | |
| 76 | #ifdef CONFIG_MCONSOLE |
| 77 | sock = mconsole_notify_socket(); |
| 78 | #endif |
| 79 | err = start_watchdog(&harddog_in_fd, &harddog_out_fd, sock); |
Jeff Dike | 42d3611 | 2007-02-10 01:43:57 -0800 | [diff] [blame] | 80 | if(err) |
| 81 | goto err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 82 | |
| 83 | timer_alive = 1; |
Jeff Dike | 42d3611 | 2007-02-10 01:43:57 -0800 | [diff] [blame] | 84 | spin_unlock(&lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 85 | return nonseekable_open(inode, file); |
Jeff Dike | 42d3611 | 2007-02-10 01:43:57 -0800 | [diff] [blame] | 86 | err: |
| 87 | spin_unlock(&lock); |
| 88 | return err; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 89 | } |
| 90 | |
| 91 | extern void stop_watchdog(int in_fd, int out_fd); |
| 92 | |
| 93 | static int harddog_release(struct inode *inode, struct file *file) |
| 94 | { |
| 95 | /* |
| 96 | * Shut off the timer. |
| 97 | */ |
Jeff Dike | 42d3611 | 2007-02-10 01:43:57 -0800 | [diff] [blame] | 98 | |
| 99 | spin_lock(&lock); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 100 | |
| 101 | stop_watchdog(harddog_in_fd, harddog_out_fd); |
| 102 | harddog_in_fd = -1; |
| 103 | harddog_out_fd = -1; |
| 104 | |
| 105 | timer_alive=0; |
Jeff Dike | 42d3611 | 2007-02-10 01:43:57 -0800 | [diff] [blame] | 106 | spin_unlock(&lock); |
| 107 | |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 108 | return 0; |
| 109 | } |
| 110 | |
| 111 | extern int ping_watchdog(int fd); |
| 112 | |
Al Viro | 4d338e1 | 2006-03-31 02:30:15 -0800 | [diff] [blame] | 113 | static ssize_t harddog_write(struct file *file, const char __user *data, size_t len, |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 114 | loff_t *ppos) |
| 115 | { |
| 116 | /* |
| 117 | * Refresh the timer. |
| 118 | */ |
| 119 | if(len) |
Jeff Dike | 5bbcbec | 2007-02-10 01:43:58 -0800 | [diff] [blame] | 120 | return ping_watchdog(harddog_out_fd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 121 | return 0; |
| 122 | } |
| 123 | |
| 124 | static int harddog_ioctl(struct inode *inode, struct file *file, |
| 125 | unsigned int cmd, unsigned long arg) |
| 126 | { |
Al Viro | 4d338e1 | 2006-03-31 02:30:15 -0800 | [diff] [blame] | 127 | void __user *argp= (void __user *)arg; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 128 | static struct watchdog_info ident = { |
| 129 | WDIOC_SETTIMEOUT, |
| 130 | 0, |
| 131 | "UML Hardware Watchdog" |
| 132 | }; |
| 133 | switch (cmd) { |
| 134 | default: |
| 135 | return -ENOTTY; |
| 136 | case WDIOC_GETSUPPORT: |
Al Viro | 4d338e1 | 2006-03-31 02:30:15 -0800 | [diff] [blame] | 137 | if(copy_to_user(argp, &ident, sizeof(ident))) |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 138 | return -EFAULT; |
| 139 | return 0; |
| 140 | case WDIOC_GETSTATUS: |
| 141 | case WDIOC_GETBOOTSTATUS: |
Al Viro | 4d338e1 | 2006-03-31 02:30:15 -0800 | [diff] [blame] | 142 | return put_user(0,(int __user *)argp); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 143 | case WDIOC_KEEPALIVE: |
Jeff Dike | 5bbcbec | 2007-02-10 01:43:58 -0800 | [diff] [blame] | 144 | return ping_watchdog(harddog_out_fd); |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 145 | } |
| 146 | } |
| 147 | |
Arjan van de Ven | 5dfe4c9 | 2007-02-12 00:55:31 -0800 | [diff] [blame] | 148 | static const struct file_operations harddog_fops = { |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 149 | .owner = THIS_MODULE, |
| 150 | .write = harddog_write, |
| 151 | .ioctl = harddog_ioctl, |
| 152 | .open = harddog_open, |
| 153 | .release = harddog_release, |
| 154 | }; |
| 155 | |
| 156 | static struct miscdevice harddog_miscdev = { |
| 157 | .minor = WATCHDOG_MINOR, |
| 158 | .name = "watchdog", |
| 159 | .fops = &harddog_fops, |
| 160 | }; |
| 161 | |
| 162 | static char banner[] __initdata = KERN_INFO "UML Watchdog Timer\n"; |
| 163 | |
| 164 | static int __init harddog_init(void) |
| 165 | { |
| 166 | int ret; |
| 167 | |
| 168 | ret = misc_register(&harddog_miscdev); |
| 169 | |
| 170 | if (ret) |
| 171 | return ret; |
| 172 | |
| 173 | printk(banner); |
| 174 | |
Jeff Dike | 5bbcbec | 2007-02-10 01:43:58 -0800 | [diff] [blame] | 175 | return 0; |
Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 176 | } |
| 177 | |
| 178 | static void __exit harddog_exit(void) |
| 179 | { |
| 180 | misc_deregister(&harddog_miscdev); |
| 181 | } |
| 182 | |
| 183 | module_init(harddog_init); |
| 184 | module_exit(harddog_exit); |