>>> On 30.09.10 at 18:16, Jeremy Fitzhardinge <jeremy@xxxxxxxx> wrote:
> On 09/30/2010 07:01 AM, Jan Beulich wrote:
>> 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.
>
> Looks good. Are you going to submit this upstream?
By sending it to you I thought I did.
Confused, Jan
>> Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>
>>
>> ---
>> 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(+)
>>
>> --- linux-2.6.36-rc6/drivers/watchdog/Kconfig
>> +++ 2.6.36-rc6-xen-watchdog/drivers/watchdog/Kconfig
>> @@ -1043,6 +1043,16 @@ 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
>> #
>> --- linux-2.6.36-rc6/drivers/watchdog/Makefile
>> +++ 2.6.36-rc6-xen-watchdog/drivers/watchdog/Makefile
>> @@ -145,6 +145,9 @@ 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
>> --- linux-2.6.36-rc6/drivers/watchdog/xen_wdt.c
>> +++ 2.6.36-rc6-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("Jen Beulich <jbeulich@xxxxxxxxxx>");
>> +MODULE_DESCRIPTION("Xen WatchDog Timer Driver");
>> +MODULE_VERSION(DRV_VERSION);
>> +MODULE_LICENSE("GPL");
>> +MODULE_ALIAS_MISCDEV(WATCHDOG_MINOR);
>> --- linux-2.6.36-rc6/include/xen/interface/sched.h
>> +++ 2.6.36-rc6-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__ */
>>
>>
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