mirror of https://gitee.com/openkylin/linux.git
188 lines
4.1 KiB
C
188 lines
4.1 KiB
C
/* 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;
|
|
|
|
lock_kernel();
|
|
spin_lock(&lock);
|
|
if(timer_alive)
|
|
goto err;
|
|
#ifdef CONFIG_WATCHDOG_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);
|
|
unlock_kernel();
|
|
return nonseekable_open(inode, file);
|
|
err:
|
|
spin_unlock(&lock);
|
|
unlock_kernel();
|
|
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 const 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);
|