180 lines
4.1 KiB
C
180 lines
4.1 KiB
C
/* UML hardware watchdog, shamelessly stolen from:
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*
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* SoftDog 0.05: A Software Watchdog Device
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*
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* (c) Copyright 1996 Alan Cox <alan@redhat.com>, All Rights Reserved.
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* http://www.redhat.com
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*
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* Neither Alan Cox nor CymruNet Ltd. admit liability nor provide
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* warranty for any of this software. This material is provided
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* "AS-IS" and at no charge.
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*
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* (c) Copyright 1995 Alan Cox <alan@lxorguk.ukuu.org.uk>
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*
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* Software only watchdog driver. Unlike its big brother the WDT501P
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* driver this won't always recover a failed machine.
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*
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* 03/96: Angelo Haritsis <ah@doc.ic.ac.uk> :
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* Modularised.
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* Added soft_margin; use upon insmod to change the timer delay.
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* NB: uses same minor as wdt (WATCHDOG_MINOR); we could use separate
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* minors.
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*
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* 19980911 Alan Cox
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* Made SMP safe for 2.3.x
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*
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* 20011127 Joel Becker (jlbec@evilplan.org>
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* Added soft_noboot; Allows testing the softdog trigger without
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* requiring a recompile.
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* Added WDIOC_GETTIMEOUT and WDIOC_SETTIMOUT.
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*/
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#include <linux/module.h>
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#include <linux/types.h>
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#include <linux/kernel.h>
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#include <linux/fs.h>
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#include <linux/mm.h>
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#include <linux/miscdevice.h>
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#include <linux/watchdog.h>
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#include <linux/reboot.h>
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#include <linux/mutex.h>
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#include <linux/init.h>
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#include <linux/spinlock.h>
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#include <linux/uaccess.h>
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#include "mconsole.h"
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MODULE_LICENSE("GPL");
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static DEFINE_MUTEX(harddog_mutex);
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static DEFINE_SPINLOCK(lock);
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static int timer_alive;
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static int harddog_in_fd = -1;
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static int harddog_out_fd = -1;
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/*
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* Allow only one person to hold it open
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*/
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extern int start_watchdog(int *in_fd_ret, int *out_fd_ret, char *sock);
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static int harddog_open(struct inode *inode, struct file *file)
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{
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int err = -EBUSY;
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char *sock = NULL;
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mutex_lock(&harddog_mutex);
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spin_lock(&lock);
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if(timer_alive)
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goto err;
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#ifdef CONFIG_WATCHDOG_NOWAYOUT
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__module_get(THIS_MODULE);
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#endif
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#ifdef CONFIG_MCONSOLE
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sock = mconsole_notify_socket();
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#endif
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err = start_watchdog(&harddog_in_fd, &harddog_out_fd, sock);
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if(err)
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goto err;
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timer_alive = 1;
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spin_unlock(&lock);
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mutex_unlock(&harddog_mutex);
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return stream_open(inode, file);
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err:
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spin_unlock(&lock);
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mutex_unlock(&harddog_mutex);
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return err;
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}
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extern void stop_watchdog(int in_fd, int out_fd);
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static int harddog_release(struct inode *inode, struct file *file)
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{
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/*
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* Shut off the timer.
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*/
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spin_lock(&lock);
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stop_watchdog(harddog_in_fd, harddog_out_fd);
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harddog_in_fd = -1;
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harddog_out_fd = -1;
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timer_alive=0;
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spin_unlock(&lock);
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return 0;
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}
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extern int ping_watchdog(int fd);
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static ssize_t harddog_write(struct file *file, const char __user *data, size_t len,
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loff_t *ppos)
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{
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/*
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* Refresh the timer.
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*/
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if(len)
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return ping_watchdog(harddog_out_fd);
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return 0;
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}
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static int harddog_ioctl_unlocked(struct file *file,
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unsigned int cmd, unsigned long arg)
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{
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void __user *argp= (void __user *)arg;
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static struct watchdog_info ident = {
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WDIOC_SETTIMEOUT,
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0,
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"UML Hardware Watchdog"
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};
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switch (cmd) {
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default:
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return -ENOTTY;
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case WDIOC_GETSUPPORT:
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if(copy_to_user(argp, &ident, sizeof(ident)))
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return -EFAULT;
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return 0;
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case WDIOC_GETSTATUS:
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case WDIOC_GETBOOTSTATUS:
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return put_user(0,(int __user *)argp);
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case WDIOC_KEEPALIVE:
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return ping_watchdog(harddog_out_fd);
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}
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}
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static long harddog_ioctl(struct file *file,
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unsigned int cmd, unsigned long arg)
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{
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long ret;
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mutex_lock(&harddog_mutex);
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ret = harddog_ioctl_unlocked(file, cmd, arg);
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mutex_unlock(&harddog_mutex);
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return ret;
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}
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static const struct file_operations harddog_fops = {
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.owner = THIS_MODULE,
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.write = harddog_write,
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.unlocked_ioctl = harddog_ioctl,
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.compat_ioctl = compat_ptr_ioctl,
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.open = harddog_open,
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.release = harddog_release,
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.llseek = no_llseek,
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};
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static struct miscdevice harddog_miscdev = {
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.minor = WATCHDOG_MINOR,
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.name = "watchdog",
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.fops = &harddog_fops,
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};
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module_misc_device(harddog_miscdev);
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