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399 lines
9.1 KiB
399 lines
9.1 KiB
From: jbeulich@novell.com
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Subject: Xen: para-virtual watchdog driver
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Patch-mainline: n/a
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--- head-2011-01-30.orig/drivers/watchdog/Kconfig 2011-01-31 12:42:35.000000000 +0100
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+++ head-2011-01-30/drivers/watchdog/Kconfig 2011-02-02 15:10:41.000000000 +0100
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@@ -1119,6 +1119,16 @@ config WATCHDOG_RIO
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# XTENSA Architecture
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+# Xen Architecture
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+
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+config XEN_WDT
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+ tristate "Xen Watchdog support"
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+ depends on PARAVIRT_XEN || XEN
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+ help
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+ Say Y here to support the hypervisor watchdog capability provided
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+ by Xen 4.0 and newer. The watchdog timeout period is normally one
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+ minute but can be changed with a boot-time parameter.
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+
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#
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# ISA-based Watchdog Cards
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#
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--- head-2011-01-30.orig/drivers/watchdog/Makefile 2011-01-31 12:42:35.000000000 +0100
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+++ head-2011-01-30/drivers/watchdog/Makefile 2011-02-02 15:10:41.000000000 +0100
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@@ -148,6 +148,9 @@ obj-$(CONFIG_WATCHDOG_CP1XXX) += cpwd.o
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# XTENSA Architecture
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+# Xen
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+obj-$(CONFIG_XEN_WDT) += xen_wdt.o
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+
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# Architecture Independant
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obj-$(CONFIG_WM831X_WATCHDOG) += wm831x_wdt.o
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obj-$(CONFIG_WM8350_WATCHDOG) += wm8350_wdt.o
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--- /dev/null 1970-01-01 00:00:00.000000000 +0000
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+++ head-2011-01-30/drivers/watchdog/xen_wdt.c 2011-02-02 15:10:41.000000000 +0100
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@@ -0,0 +1,360 @@
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+/*
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+ * Xen Watchdog Driver
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+ *
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+ * (c) Copyright 2010 Novell, Inc.
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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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+
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+#define DRV_NAME "wdt"
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+#define DRV_VERSION "0.01"
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+#define PFX DRV_NAME ": "
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+
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+#include <linux/bug.h>
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+#include <linux/errno.h>
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+#include <linux/fs.h>
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+#include <linux/hrtimer.h>
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+#include <linux/kernel.h>
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+#include <linux/ktime.h>
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+#include <linux/init.h>
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+#include <linux/miscdevice.h>
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+#include <linux/module.h>
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+#include <linux/moduleparam.h>
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+#include <linux/platform_device.h>
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+#include <linux/spinlock.h>
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+#include <linux/uaccess.h>
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+#include <linux/watchdog.h>
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+#ifdef CONFIG_PARAVIRT_XEN
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+#include <xen/xen.h>
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+#include <asm/xen/hypercall.h>
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+#endif
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+#include <xen/interface/sched.h>
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+
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+static struct platform_device *platform_device;
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+static DEFINE_SPINLOCK(wdt_lock);
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+static struct sched_watchdog wdt;
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+static __kernel_time_t wdt_expires;
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+static bool is_active, expect_release;
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+
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+#define WATCHDOG_TIMEOUT 60 /* in seconds */
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+static unsigned int timeout = WATCHDOG_TIMEOUT;
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+module_param(timeout, uint, S_IRUGO);
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+MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds "
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+ "(default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ")");
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+
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+static bool nowayout = WATCHDOG_NOWAYOUT;
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+module_param(nowayout, bool, S_IRUGO);
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+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
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+ "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
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+
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+static inline __kernel_time_t set_timeout(void)
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+{
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+ wdt.timeout = timeout;
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+ return ktime_to_timespec(ktime_get()).tv_sec + timeout;
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+}
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+
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+static int xen_wdt_start(void)
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+{
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+ __kernel_time_t expires;
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+ int err;
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+
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+ spin_lock(&wdt_lock);
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+
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+ expires = set_timeout();
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+ if (!wdt.id)
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+ err = HYPERVISOR_sched_op(SCHEDOP_watchdog, &wdt);
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+ else
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+ err = -EBUSY;
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+ if (err > 0) {
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+ wdt.id = err;
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+ wdt_expires = expires;
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+ err = 0;
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+ } else
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+ BUG_ON(!err);
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+
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+ spin_unlock(&wdt_lock);
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+
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+ return err;
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+}
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+
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+static int xen_wdt_stop(void)
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+{
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+ int err = 0;
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+
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+ spin_lock(&wdt_lock);
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+
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+ wdt.timeout = 0;
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+ if (wdt.id)
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+ err = HYPERVISOR_sched_op(SCHEDOP_watchdog, &wdt);
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+ if (!err)
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+ wdt.id = 0;
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+
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+ spin_unlock(&wdt_lock);
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+
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+ return err;
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+}
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+
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+static int xen_wdt_kick(void)
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+{
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+ __kernel_time_t expires;
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+ int err;
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+
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+ spin_lock(&wdt_lock);
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+
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+ expires = set_timeout();
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+ if (wdt.id)
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+ err = HYPERVISOR_sched_op(SCHEDOP_watchdog, &wdt);
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+ else
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+ err = -ENXIO;
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+ if (!err)
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+ wdt_expires = expires;
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+
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+ spin_unlock(&wdt_lock);
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+
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+ return err;
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+}
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+
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+static int xen_wdt_open(struct inode *inode, struct file *file)
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+{
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+ int err;
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+
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+ /* /dev/watchdog can only be opened once */
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+ if (xchg(&is_active, true))
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+ return -EBUSY;
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+
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+ err = xen_wdt_start();
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+ if (err == -EBUSY)
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+ err = xen_wdt_kick();
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+ return err ?: nonseekable_open(inode, file);
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+}
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+
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+static int xen_wdt_release(struct inode *inode, struct file *file)
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+{
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+ if (expect_release)
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+ xen_wdt_stop();
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+ else {
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+ pr_crit(PFX "unexpected close, not stopping watchdog!\n");
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+ xen_wdt_kick();
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+ }
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+ is_active = false;
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+ expect_release = false;
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+ return 0;
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+}
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+
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+static ssize_t xen_wdt_write(struct file *file, const char __user *data,
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+ size_t len, loff_t *ppos)
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+{
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+ /* See if we got the magic character 'V' and reload the timer */
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+ if (len) {
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+ if (!nowayout) {
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+ size_t i;
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+
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+ /* in case it was set long ago */
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+ expect_release = false;
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+
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+ /* scan to see whether or not we got the magic
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+ character */
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+ for (i = 0; i != len; i++) {
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+ char c;
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+ if (get_user(c, data + i))
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+ return -EFAULT;
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+ if (c == 'V')
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+ expect_release = true;
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+ }
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+ }
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+
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+ /* someone wrote to us, we should reload the timer */
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+ xen_wdt_kick();
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+ }
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+ return len;
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+}
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+
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+static long xen_wdt_ioctl(struct file *file, unsigned int cmd,
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+ unsigned long arg)
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+{
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+ int new_options, retval = -EINVAL;
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+ int new_timeout;
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+ int __user *argp = (void __user *)arg;
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+ static const struct watchdog_info ident = {
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+ .options = WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
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+ .firmware_version = 0,
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+ .identity = DRV_NAME,
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+ };
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+
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+ switch (cmd) {
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+ case WDIOC_GETSUPPORT:
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+ return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
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+
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+ case WDIOC_GETSTATUS:
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+ case WDIOC_GETBOOTSTATUS:
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+ return put_user(0, argp);
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+
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+ case WDIOC_SETOPTIONS:
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+ if (get_user(new_options, argp))
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+ return -EFAULT;
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+
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+ if (new_options & WDIOS_DISABLECARD)
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+ retval = xen_wdt_stop();
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+ if (new_options & WDIOS_ENABLECARD) {
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+ retval = xen_wdt_start();
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+ if (retval == -EBUSY)
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+ retval = xen_wdt_kick();
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+ }
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+ return retval;
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+
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+ case WDIOC_KEEPALIVE:
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+ xen_wdt_kick();
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+ return 0;
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+
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+ case WDIOC_SETTIMEOUT:
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+ if (get_user(new_timeout, argp))
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+ return -EFAULT;
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+ if (!new_timeout)
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+ return -EINVAL;
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+ timeout = new_timeout;
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+ xen_wdt_kick();
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+ /* fall through */
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+ case WDIOC_GETTIMEOUT:
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+ return put_user(timeout, argp);
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+
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+ case WDIOC_GETTIMELEFT:
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+ retval = wdt_expires - ktime_to_timespec(ktime_get()).tv_sec;
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+ return put_user(retval, argp);
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+ }
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+
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+ return -ENOTTY;
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+}
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+
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+static const struct file_operations xen_wdt_fops = {
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+ .owner = THIS_MODULE,
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+ .llseek = no_llseek,
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+ .write = xen_wdt_write,
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+ .unlocked_ioctl = xen_wdt_ioctl,
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+ .open = xen_wdt_open,
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+ .release = xen_wdt_release,
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+};
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+
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+static struct miscdevice xen_wdt_miscdev = {
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+ .minor = WATCHDOG_MINOR,
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+ .name = "watchdog",
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+ .fops = &xen_wdt_fops,
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+};
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+
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+static int __devinit xen_wdt_probe(struct platform_device *dev)
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+{
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+ struct sched_watchdog wd = { .id = ~0 };
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+ int ret = HYPERVISOR_sched_op(SCHEDOP_watchdog, &wd);
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+
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+ switch (ret) {
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+ case -EINVAL:
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+ if (!timeout) {
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+ timeout = WATCHDOG_TIMEOUT;
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+ pr_info(PFX "timeout value invalid, using %d\n",
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+ timeout);
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+ }
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+
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+ ret = misc_register(&xen_wdt_miscdev);
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+ if (ret) {
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+ pr_err(PFX "can't register miscdev on minor=%d (%d)\n",
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+ WATCHDOG_MINOR, ret);
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+ break;
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+ }
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+
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+ pr_info(PFX "initialized (timeout=%ds, nowayout=%d)\n",
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+ timeout, nowayout);
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+ break;
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+
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+ case -ENOSYS:
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+ pr_info(PFX "not supported\n");
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+ ret = -ENODEV;
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+ break;
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+
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+ default:
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+ pr_warning(PFX "bogus return value %d\n", ret);
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+ break;
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+ }
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+
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+ return ret;
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+}
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+
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+static int __devexit xen_wdt_remove(struct platform_device *dev)
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+{
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+ /* Stop the timer before we leave */
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+ if (!nowayout)
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+ xen_wdt_stop();
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+
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+ misc_deregister(&xen_wdt_miscdev);
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+
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+ return 0;
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+}
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+
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+static void xen_wdt_shutdown(struct platform_device *dev)
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+{
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+ xen_wdt_stop();
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+}
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+
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+static int xen_wdt_suspend(struct platform_device *dev, pm_message_t state)
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+{
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+ return xen_wdt_stop();
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+}
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+
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+static int xen_wdt_resume(struct platform_device *dev)
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+{
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+ return xen_wdt_start();
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+}
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+
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+static struct platform_driver xen_wdt_driver = {
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+ .probe = xen_wdt_probe,
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+ .remove = __devexit_p(xen_wdt_remove),
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+ .shutdown = xen_wdt_shutdown,
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+ .suspend = xen_wdt_suspend,
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+ .resume = xen_wdt_resume,
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+ .driver = {
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+ .owner = THIS_MODULE,
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+ .name = DRV_NAME,
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+ },
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+};
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+
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+static int __init xen_wdt_init_module(void)
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+{
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+ int err;
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+
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+#ifdef CONFIG_PARAVIRT_XEN
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+ if (!xen_domain())
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+ return -ENODEV;
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+#endif
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+
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+ pr_info(PFX "Xen WatchDog Timer Driver v%s\n", DRV_VERSION);
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+
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+ err = platform_driver_register(&xen_wdt_driver);
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+ if (err)
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+ return err;
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+
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+ platform_device = platform_device_register_simple(DRV_NAME,
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+ -1, NULL, 0);
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+ if (IS_ERR(platform_device)) {
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+ err = PTR_ERR(platform_device);
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+ platform_driver_unregister(&xen_wdt_driver);
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+ }
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+
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+ return err;
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+}
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+
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+static void __exit xen_wdt_cleanup_module(void)
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+{
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+ platform_device_unregister(platform_device);
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+ platform_driver_unregister(&xen_wdt_driver);
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+ pr_info(PFX "module unloaded\n");
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+}
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+
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+module_init(xen_wdt_init_module);
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+module_exit(xen_wdt_cleanup_module);
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+
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+MODULE_AUTHOR("Jan Beulich <jbeulich@novell.com>");
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+MODULE_DESCRIPTION("Xen WatchDog Timer Driver");
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+MODULE_VERSION(DRV_VERSION);
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+MODULE_LICENSE("GPL");
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+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
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