On 09/30/2010 11:56 PM, Jan Beulich wrote:
> >>> 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.
I'm not the exclusive path for upstream Xen; I'm happy to ack things and
let others submit them. But I'm also happy to submit this too.
J
> 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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