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208 lines
4.5 KiB
208 lines
4.5 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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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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#define DRV_NAME "xen_wdt" |
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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/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/watchdog.h> |
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#include <xen/xen.h> |
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#include <asm/xen/hypercall.h> |
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#include <xen/interface/sched.h> |
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static struct platform_device *platform_device; |
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static struct sched_watchdog wdt; |
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static time64_t wdt_expires; |
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#define WATCHDOG_TIMEOUT 60 /* in seconds */ |
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static unsigned int 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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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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static inline time64_t set_timeout(struct watchdog_device *wdd) |
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{ |
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wdt.timeout = wdd->timeout; |
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return ktime_get_seconds() + wdd->timeout; |
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} |
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static int xen_wdt_start(struct watchdog_device *wdd) |
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{ |
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time64_t expires; |
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int err; |
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expires = set_timeout(wdd); |
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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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return err; |
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} |
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static int xen_wdt_stop(struct watchdog_device *wdd) |
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{ |
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int err = 0; |
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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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return err; |
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} |
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static int xen_wdt_kick(struct watchdog_device *wdd) |
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{ |
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time64_t expires; |
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int err; |
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expires = set_timeout(wdd); |
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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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return err; |
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} |
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static unsigned int xen_wdt_get_timeleft(struct watchdog_device *wdd) |
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{ |
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return wdt_expires - ktime_get_seconds(); |
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} |
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static struct watchdog_info xen_wdt_info = { |
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.identity = DRV_NAME, |
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.options = WDIOF_SETTIMEOUT | WDIOF_KEEPALIVEPING | WDIOF_MAGICCLOSE, |
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}; |
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static const struct watchdog_ops xen_wdt_ops = { |
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.owner = THIS_MODULE, |
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.start = xen_wdt_start, |
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.stop = xen_wdt_stop, |
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.ping = xen_wdt_kick, |
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.get_timeleft = xen_wdt_get_timeleft, |
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}; |
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static struct watchdog_device xen_wdt_dev = { |
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.info = &xen_wdt_info, |
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.ops = &xen_wdt_ops, |
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.timeout = WATCHDOG_TIMEOUT, |
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}; |
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static int xen_wdt_probe(struct platform_device *pdev) |
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{ |
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struct device *dev = &pdev->dev; |
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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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if (ret == -ENOSYS) { |
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dev_err(dev, "watchdog not supported by hypervisor\n"); |
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return -ENODEV; |
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} |
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if (ret != -EINVAL) { |
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dev_err(dev, "unexpected hypervisor error (%d)\n", ret); |
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return -ENODEV; |
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} |
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watchdog_init_timeout(&xen_wdt_dev, timeout, NULL); |
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watchdog_set_nowayout(&xen_wdt_dev, nowayout); |
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watchdog_stop_on_reboot(&xen_wdt_dev); |
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watchdog_stop_on_unregister(&xen_wdt_dev); |
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ret = devm_watchdog_register_device(dev, &xen_wdt_dev); |
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if (ret) |
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return ret; |
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dev_info(dev, "initialized (timeout=%ds, nowayout=%d)\n", |
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xen_wdt_dev.timeout, nowayout); |
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return 0; |
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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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typeof(wdt.id) id = wdt.id; |
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int rc = xen_wdt_stop(&xen_wdt_dev); |
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wdt.id = id; |
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return rc; |
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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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if (!wdt.id) |
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return 0; |
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wdt.id = 0; |
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return xen_wdt_start(&xen_wdt_dev); |
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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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.suspend = xen_wdt_suspend, |
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.resume = xen_wdt_resume, |
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.driver = { |
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.name = DRV_NAME, |
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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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if (!xen_domain()) |
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return -ENODEV; |
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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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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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return err; |
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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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} |
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module_init(xen_wdt_init_module); |
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module_exit(xen_wdt_cleanup_module); |
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MODULE_AUTHOR("Jan Beulich <[email protected]>"); |
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MODULE_DESCRIPTION("Xen WatchDog Timer Driver"); |
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MODULE_LICENSE("GPL");
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