| /* UML hardware watchdog, shamelessly stolen from: |
| * |
| * SoftDog 0.05: A Software Watchdog Device |
| * |
| * (c) Copyright 1996 Alan Cox <alan@redhat.com>, All Rights Reserved. |
| * http://www.redhat.com |
| * |
| * This program is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU General Public License |
| * as published by the Free Software Foundation; either version |
| * 2 of the License, or (at your option) any later version. |
| * |
| * 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. |
| * |
| * 03/96: Angelo Haritsis <ah@doc.ic.ac.uk> : |
| * Modularised. |
| * Added soft_margin; use upon insmod to change the timer delay. |
| * NB: uses same minor as wdt (WATCHDOG_MINOR); we could use separate |
| * minors. |
| * |
| * 19980911 Alan Cox |
| * Made SMP safe for 2.3.x |
| * |
| * 20011127 Joel Becker (jlbec@evilplan.org> |
| * Added soft_noboot; Allows testing the softdog trigger without |
| * requiring a recompile. |
| * Added WDIOC_GETTIMEOUT and WDIOC_SETTIMOUT. |
| */ |
| |
| #include <linux/module.h> |
| #include <linux/types.h> |
| #include <linux/kernel.h> |
| #include <linux/fs.h> |
| #include <linux/mm.h> |
| #include <linux/miscdevice.h> |
| #include <linux/watchdog.h> |
| #include <linux/reboot.h> |
| #include <linux/smp_lock.h> |
| #include <linux/init.h> |
| #include <linux/spinlock.h> |
| #include <asm/uaccess.h> |
| #include "mconsole.h" |
| |
| MODULE_LICENSE("GPL"); |
| |
| static DEFINE_SPINLOCK(lock); |
| static int timer_alive; |
| static int harddog_in_fd = -1; |
| static int harddog_out_fd = -1; |
| |
| /* |
| * Allow only one person to hold it open |
| */ |
| |
| extern int start_watchdog(int *in_fd_ret, int *out_fd_ret, char *sock); |
| |
| static int harddog_open(struct inode *inode, struct file *file) |
| { |
| int err = -EBUSY; |
| char *sock = NULL; |
| |
| spin_lock(&lock); |
| if(timer_alive) |
| goto err; |
| #ifdef CONFIG_HARDDOG_NOWAYOUT |
| __module_get(THIS_MODULE); |
| #endif |
| |
| #ifdef CONFIG_MCONSOLE |
| sock = mconsole_notify_socket(); |
| #endif |
| err = start_watchdog(&harddog_in_fd, &harddog_out_fd, sock); |
| if(err) |
| goto err; |
| |
| timer_alive = 1; |
| spin_unlock(&lock); |
| return nonseekable_open(inode, file); |
| err: |
| spin_unlock(&lock); |
| return err; |
| } |
| |
| extern void stop_watchdog(int in_fd, int out_fd); |
| |
| static int harddog_release(struct inode *inode, struct file *file) |
| { |
| /* |
| * Shut off the timer. |
| */ |
| |
| spin_lock(&lock); |
| |
| stop_watchdog(harddog_in_fd, harddog_out_fd); |
| harddog_in_fd = -1; |
| harddog_out_fd = -1; |
| |
| timer_alive=0; |
| spin_unlock(&lock); |
| |
| return 0; |
| } |
| |
| extern int ping_watchdog(int fd); |
| |
| static ssize_t harddog_write(struct file *file, const char __user *data, size_t len, |
| loff_t *ppos) |
| { |
| /* |
| * Refresh the timer. |
| */ |
| if(len) |
| return(ping_watchdog(harddog_out_fd)); |
| return 0; |
| } |
| |
| static int harddog_ioctl(struct inode *inode, struct file *file, |
| unsigned int cmd, unsigned long arg) |
| { |
| void __user *argp= (void __user *)arg; |
| static struct watchdog_info ident = { |
| WDIOC_SETTIMEOUT, |
| 0, |
| "UML Hardware Watchdog" |
| }; |
| switch (cmd) { |
| default: |
| return -ENOTTY; |
| case WDIOC_GETSUPPORT: |
| if(copy_to_user(argp, &ident, sizeof(ident))) |
| return -EFAULT; |
| return 0; |
| case WDIOC_GETSTATUS: |
| case WDIOC_GETBOOTSTATUS: |
| return put_user(0,(int __user *)argp); |
| case WDIOC_KEEPALIVE: |
| return(ping_watchdog(harddog_out_fd)); |
| } |
| } |
| |
| static struct file_operations harddog_fops = { |
| .owner = THIS_MODULE, |
| .write = harddog_write, |
| .ioctl = harddog_ioctl, |
| .open = harddog_open, |
| .release = harddog_release, |
| }; |
| |
| static struct miscdevice harddog_miscdev = { |
| .minor = WATCHDOG_MINOR, |
| .name = "watchdog", |
| .fops = &harddog_fops, |
| }; |
| |
| static char banner[] __initdata = KERN_INFO "UML Watchdog Timer\n"; |
| |
| static int __init harddog_init(void) |
| { |
| int ret; |
| |
| ret = misc_register(&harddog_miscdev); |
| |
| if (ret) |
| return ret; |
| |
| printk(banner); |
| |
| return(0); |
| } |
| |
| static void __exit harddog_exit(void) |
| { |
| misc_deregister(&harddog_miscdev); |
| } |
| |
| module_init(harddog_init); |
| module_exit(harddog_exit); |
| |
| /* |
| * Overrides for Emacs so that we follow Linus's tabbing style. |
| * Emacs will notice this stuff at the end of the file and automatically |
| * adjust the settings for this buffer only. This must remain at the end |
| * of the file. |
| * --------------------------------------------------------------------------- |
| * Local variables: |
| * c-file-style: "linux" |
| * End: |
| */ |