WARNING - OLD ARCHIVES

This is an archived copy of the Xen.org mailing list, which we have preserved to ensure that existing links to archives are not broken. The live archive, which contains the latest emails, can be found at http://lists.xen.org/
   
 
 
Xen 
 
Home Products Support Community News
 
   
 

xen-devel

[Xen-devel] [PATCH, resend] Xen watchdog driver

To: <linux-watchdog@xxxxxxxxxxxxxxx>
Subject: [Xen-devel] [PATCH, resend] Xen watchdog driver
From: "Jan Beulich" <JBeulich@xxxxxxxxxx>
Date: Thu, 27 Jan 2011 15:42:48 +0000
Cc: Jeremy Fitzhardinge <jeremy@xxxxxxxx>, "xen-devel@xxxxxxxxxxxxxxxxxxx" <xen-devel@xxxxxxxxxxxxxxxxxxx>, Ian Campbell <ian.campbell@xxxxxxxxxx>
Delivery-date: Thu, 27 Jan 2011 07:44:35 -0800
Envelope-to: www-data@xxxxxxxxxxxxxxxxxxx
List-help: <mailto:xen-devel-request@lists.xensource.com?subject=help>
List-id: Xen developer discussion <xen-devel.lists.xensource.com>
List-post: <mailto:xen-devel@lists.xensource.com>
List-subscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=subscribe>
List-unsubscribe: <http://lists.xensource.com/mailman/listinfo/xen-devel>, <mailto:xen-devel-request@lists.xensource.com?subject=unsubscribe>
Sender: xen-devel-bounces@xxxxxxxxxxxxxxxxxxx
While the hypervisor change adding SCHEDOP_watchdog support included a
daemon to make use of the new functionality, having a kernel driver
for /dev/watchdog so that user space code doesn't need to distinguish
non-Xen and Xen seems to be preferable.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>
Acked-by: Ian Campbell <ian.campbell@xxxxxxxxxx> (on the Xen aspects of the 
patch)
Cc: Jeremy Fitzhardinge <jeremy@xxxxxxxx>

---
 drivers/watchdog/Kconfig      |   10 +
 drivers/watchdog/Makefile     |    3 
 drivers/watchdog/xen_wdt.c    |  359 ++++++++++++++++++++++++++++++++++++++++++
 include/xen/interface/sched.h |   34 +++
 4 files changed, 406 insertions(+)

--- 2.6.38-rc2/drivers/watchdog/Kconfig
+++ 2.6.38-rc2-xen-watchdog/drivers/watchdog/Kconfig
@@ -1119,6 +1119,16 @@ config WATCHDOG_RIO
 
 # XTENSA Architecture
 
+# Xen Architecture
+
+config XEN_WDT
+       tristate "Xen Watchdog support"
+       depends on XEN
+       help
+         Say Y here to support the hypervisor watchdog capability provided
+         by Xen 4.0 and newer.  The watchdog timeout period is normally one
+         minute but can be changed with a boot-time parameter.
+
 #
 # ISA-based Watchdog Cards
 #
--- 2.6.38-rc2/drivers/watchdog/Makefile
+++ 2.6.38-rc2-xen-watchdog/drivers/watchdog/Makefile
@@ -148,6 +148,9 @@ obj-$(CONFIG_WATCHDOG_CP1XXX)               += cpwd.o
 
 # XTENSA Architecture
 
+# Xen
+obj-$(CONFIG_XEN_WDT) += xen_wdt.o
+
 # Architecture Independant
 obj-$(CONFIG_WM831X_WATCHDOG) += wm831x_wdt.o
 obj-$(CONFIG_WM8350_WATCHDOG) += wm8350_wdt.o
--- 2.6.38-rc2/drivers/watchdog/xen_wdt.c
+++ 2.6.38-rc2-xen-watchdog/drivers/watchdog/xen_wdt.c
@@ -0,0 +1,359 @@
+/*
+ *     Xen Watchdog Driver
+ *
+ *     (c) Copyright 2010 Novell, Inc.
+ *
+ *     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.
+ */
+
+#define DRV_NAME       "wdt"
+#define DRV_VERSION    "0.01"
+#define PFX            DRV_NAME ": "
+
+#include <linux/bug.h>
+#include <linux/errno.h>
+#include <linux/fs.h>
+#include <linux/hrtimer.h>
+#include <linux/kernel.h>
+#include <linux/ktime.h>
+#include <linux/init.h>
+#include <linux/miscdevice.h>
+#include <linux/module.h>
+#include <linux/moduleparam.h>
+#include <linux/platform_device.h>
+#include <linux/spinlock.h>
+#include <linux/uaccess.h>
+#include <linux/watchdog.h>
+#include <xen/xen.h>
+#include <asm/xen/hypercall.h>
+#include <xen/interface/sched.h>
+
+static struct platform_device *platform_device;
+static DEFINE_SPINLOCK(wdt_lock);
+static struct sched_watchdog wdt;
+static __kernel_time_t wdt_expires;
+static bool is_active, expect_release;
+
+#define WATCHDOG_TIMEOUT 60 /* in seconds */
+static unsigned int timeout = WATCHDOG_TIMEOUT;
+module_param(timeout, uint, S_IRUGO);
+MODULE_PARM_DESC(timeout, "Watchdog timeout in seconds "
+       "(default=" __MODULE_STRING(WATCHDOG_TIMEOUT) ")");
+
+static bool nowayout = WATCHDOG_NOWAYOUT;
+module_param(nowayout, bool, S_IRUGO);
+MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started "
+       "(default=" __MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
+
+static inline __kernel_time_t set_timeout(void)
+{
+       wdt.timeout = timeout;
+       return ktime_to_timespec(ktime_get()).tv_sec + timeout;
+}
+
+static int xen_wdt_start(void)
+{
+       __kernel_time_t expires;
+       int err;
+
+       spin_lock(&wdt_lock);
+
+       expires = set_timeout();
+       if (!wdt.id)
+               err = HYPERVISOR_sched_op(SCHEDOP_watchdog, &wdt);
+       else
+               err = -EBUSY;
+       if (err > 0) {
+               wdt.id = err;
+               wdt_expires = expires;
+               err = 0;
+       } else
+               BUG_ON(!err);
+
+       spin_unlock(&wdt_lock);
+
+       return err;
+}
+
+static int xen_wdt_stop(void)
+{
+       int err = 0;
+
+       spin_lock(&wdt_lock);
+
+       wdt.timeout = 0;
+       if (wdt.id)
+               err = HYPERVISOR_sched_op(SCHEDOP_watchdog, &wdt);
+       if (!err)
+               wdt.id = 0;
+
+       spin_unlock(&wdt_lock);
+
+       return err;
+}
+
+static int xen_wdt_kick(void)
+{
+       __kernel_time_t expires;
+       int err;
+
+       spin_lock(&wdt_lock);
+
+       expires = set_timeout();
+       if (wdt.id)
+               err = HYPERVISOR_sched_op(SCHEDOP_watchdog, &wdt);
+       else
+               err = -ENXIO;
+       if (!err)
+               wdt_expires = expires;
+
+       spin_unlock(&wdt_lock);
+
+       return err;
+}
+
+static int xen_wdt_open(struct inode *inode, struct file *file)
+{
+       int err;
+
+       /* /dev/watchdog can only be opened once */
+       if (xchg(&is_active, true))
+               return -EBUSY;
+
+       err = xen_wdt_start();
+       if (err == -EBUSY)
+               err = xen_wdt_kick();
+       return err ?: nonseekable_open(inode, file);
+}
+
+static int xen_wdt_release(struct inode *inode, struct file *file)
+{
+       if (expect_release)
+               xen_wdt_stop();
+       else {
+               printk(KERN_CRIT PFX
+                      "unexpected close, not stopping watchdog!\n");
+               xen_wdt_kick();
+       }
+       is_active = false;
+       expect_release = false;
+       return 0;
+}
+
+static ssize_t xen_wdt_write(struct file *file, const char __user *data,
+                            size_t len, loff_t *ppos)
+{
+       /* See if we got the magic character 'V' and reload the timer */
+       if (len) {
+               if (!nowayout) {
+                       size_t i;
+
+                       /* in case it was set long ago */
+                       expect_release = false;
+
+                       /* scan to see whether or not we got the magic
+                          character */
+                       for (i = 0; i != len; i++) {
+                               char c;
+                               if (get_user(c, data + i))
+                                       return -EFAULT;
+                               if (c == 'V')
+                                       expect_release = true;
+                       }
+               }
+
+               /* someone wrote to us, we should reload the timer */
+               xen_wdt_kick();
+       }
+       return len;
+}
+
+static long xen_wdt_ioctl(struct file *file, unsigned int cmd,
+                         unsigned long arg)
+{
+       int new_options, retval = -EINVAL;
+       int new_timeout;
+       int __user *argp = (void __user *)arg;
+       static const struct watchdog_info ident = {
+               .options =              WDIOF_SETTIMEOUT | WDIOF_MAGICCLOSE,
+               .firmware_version =     0,
+               .identity =             DRV_NAME,
+       };
+
+       switch (cmd) {
+       case WDIOC_GETSUPPORT:
+               return copy_to_user(argp, &ident, sizeof(ident)) ? -EFAULT : 0;
+
+       case WDIOC_GETSTATUS:
+       case WDIOC_GETBOOTSTATUS:
+               return put_user(0, argp);
+
+       case WDIOC_SETOPTIONS:
+               if (get_user(new_options, argp))
+                       return -EFAULT;
+
+               if (new_options & WDIOS_DISABLECARD)
+                       retval = xen_wdt_stop();
+               if (new_options & WDIOS_ENABLECARD) {
+                       retval = xen_wdt_start();
+                       if (retval == -EBUSY)
+                               retval = xen_wdt_kick();
+               }
+               return retval;
+
+       case WDIOC_KEEPALIVE:
+               xen_wdt_kick();
+               return 0;
+
+       case WDIOC_SETTIMEOUT:
+               if (get_user(new_timeout, argp))
+                       return -EFAULT;
+               if (!new_timeout)
+                       return -EINVAL;
+               timeout = new_timeout;
+               xen_wdt_kick();
+               /* fall through */
+       case WDIOC_GETTIMEOUT:
+               return put_user(timeout, argp);
+
+       case WDIOC_GETTIMELEFT:
+               retval = wdt_expires - ktime_to_timespec(ktime_get()).tv_sec;
+               return put_user(retval, argp);
+       }
+
+       return -ENOTTY;
+}
+
+static const struct file_operations xen_wdt_fops = {
+       .owner =                THIS_MODULE,
+       .llseek =               no_llseek,
+       .write =                xen_wdt_write,
+       .unlocked_ioctl =       xen_wdt_ioctl,
+       .open =                 xen_wdt_open,
+       .release =              xen_wdt_release,
+};
+
+static struct miscdevice xen_wdt_miscdev = {
+       .minor =        WATCHDOG_MINOR,
+       .name =         "watchdog",
+       .fops =         &xen_wdt_fops,
+};
+
+static int __devinit xen_wdt_probe(struct platform_device *dev)
+{
+       struct sched_watchdog wd = { .id = ~0 };
+       int ret = HYPERVISOR_sched_op(SCHEDOP_watchdog, &wd);
+
+       switch (ret) {
+       case -EINVAL:
+               if (!timeout) {
+                       timeout = WATCHDOG_TIMEOUT;
+                       printk(KERN_INFO PFX
+                              "timeout value invalid, using %d\n", timeout);
+               }
+
+               ret = misc_register(&xen_wdt_miscdev);
+               if (ret) {
+                       printk(KERN_ERR PFX
+                              "cannot register miscdev on minor=%d (%d)\n",
+                              WATCHDOG_MINOR, ret);
+                       break;
+               }
+
+               printk(KERN_INFO PFX
+                      "initialized (timeout=%ds, nowayout=%d)\n",
+                      timeout, nowayout);
+               break;
+
+       case -ENOSYS:
+               printk(KERN_INFO PFX "not supported\n");
+               ret = -ENODEV;
+               break;
+
+       default:
+               printk(KERN_INFO PFX "bogus return value %d\n", ret);
+               break;
+       }
+
+       return ret;
+}
+
+static int __devexit xen_wdt_remove(struct platform_device *dev)
+{
+       /* Stop the timer before we leave */
+       if (!nowayout)
+               xen_wdt_stop();
+
+       misc_deregister(&xen_wdt_miscdev);
+
+       return 0;
+}
+
+static void xen_wdt_shutdown(struct platform_device *dev)
+{
+       xen_wdt_stop();
+}
+
+static int xen_wdt_suspend(struct platform_device *dev, pm_message_t state)
+{
+       return xen_wdt_stop();
+}
+
+static int xen_wdt_resume(struct platform_device *dev)
+{
+       return xen_wdt_start();
+}
+
+static struct platform_driver xen_wdt_driver = {
+       .probe          = xen_wdt_probe,
+       .remove         = __devexit_p(xen_wdt_remove),
+       .shutdown       = xen_wdt_shutdown,
+       .suspend        = xen_wdt_suspend,
+       .resume         = xen_wdt_resume,
+       .driver         = {
+               .owner  = THIS_MODULE,
+               .name   = DRV_NAME,
+       },
+};
+
+static int __init xen_wdt_init_module(void)
+{
+       int err;
+
+       if (!xen_domain())
+               return -ENODEV;
+
+       printk(KERN_INFO PFX "Xen WatchDog Timer Driver v%s\n", DRV_VERSION);
+
+       err = platform_driver_register(&xen_wdt_driver);
+       if (err)
+               return err;
+
+       platform_device = platform_device_register_simple(DRV_NAME,
+                                                                 -1, NULL, 0);
+       if (IS_ERR(platform_device)) {
+               err = PTR_ERR(platform_device);
+               platform_driver_unregister(&xen_wdt_driver);
+       }
+
+       return err;
+}
+
+static void __exit xen_wdt_cleanup_module(void)
+{
+       platform_device_unregister(platform_device);
+       platform_driver_unregister(&xen_wdt_driver);
+       printk(KERN_INFO PFX "module unloaded\n");
+}
+
+module_init(xen_wdt_init_module);
+module_exit(xen_wdt_cleanup_module);
+
+MODULE_AUTHOR("Jan Beulich <jbeulich@xxxxxxxxxx>");
+MODULE_DESCRIPTION("Xen WatchDog Timer Driver");
+MODULE_VERSION(DRV_VERSION);
+MODULE_LICENSE("GPL");
+MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
--- 2.6.38-rc2/include/xen/interface/sched.h
+++ 2.6.38-rc2-xen-watchdog/include/xen/interface/sched.h
@@ -65,6 +65,39 @@ struct sched_poll {
 DEFINE_GUEST_HANDLE_STRUCT(sched_poll);
 
 /*
+ * Declare a shutdown for another domain. The main use of this function is
+ * in interpreting shutdown requests and reasons for fully-virtualized
+ * domains.  A para-virtualized domain may use SCHEDOP_shutdown directly.
+ * @arg == pointer to sched_remote_shutdown structure.
+ */
+#define SCHEDOP_remote_shutdown        4
+struct sched_remote_shutdown {
+    domid_t domain_id;         /* Remote domain ID */
+    unsigned int reason;       /* SHUTDOWN_xxx reason */
+};
+
+/*
+ * Latch a shutdown code, so that when the domain later shuts down it
+ * reports this code to the control tools.
+ * @arg == as for SCHEDOP_shutdown.
+ */
+#define SCHEDOP_shutdown_code 5
+
+/*
+ * Setup, poke and destroy a domain watchdog timer.
+ * @arg == pointer to sched_watchdog structure.
+ * With id == 0, setup a domain watchdog timer to cause domain shutdown
+ *               after timeout, returns watchdog id.
+ * With id != 0 and timeout == 0, destroy domain watchdog timer.
+ * With id != 0 and timeout != 0, poke watchdog timer and set new timeout.
+ */
+#define SCHEDOP_watchdog    6
+struct sched_watchdog {
+    uint32_t id;                /* watchdog ID */
+    uint32_t timeout;           /* timeout */
+};
+
+/*
  * Reason codes for SCHEDOP_shutdown. These may be interpreted by control
  * software to determine the appropriate action. For the most part, Xen does
  * not care about the shutdown code.
@@ -73,5 +106,6 @@ DEFINE_GUEST_HANDLE_STRUCT(sched_poll);
 #define SHUTDOWN_reboot     1  /* Clean up, kill, and then restart.          */
 #define SHUTDOWN_suspend    2  /* Clean up, save suspend info, kill.         */
 #define SHUTDOWN_crash      3  /* Tell controller we've crashed.             */
+#define SHUTDOWN_watchdog   4  /* Restart because watchdog time expired.     */
 
 #endif /* __XEN_PUBLIC_SCHED_H__ */



_______________________________________________
Xen-devel mailing list
Xen-devel@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-devel

<Prev in Thread] Current Thread [Next in Thread>
  • [Xen-devel] [PATCH, resend] Xen watchdog driver, Jan Beulich <=