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1289 lines
32 KiB
1289 lines
32 KiB
// SPDX-License-Identifier: GPL-2.0+ |
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/* |
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* watchdog_dev.c |
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* |
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* (c) Copyright 2008-2011 Alan Cox <[email protected]>, |
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* All Rights Reserved. |
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* |
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* (c) Copyright 2008-2011 Wim Van Sebroeck <[email protected]>. |
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* |
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* (c) Copyright 2021 Hewlett Packard Enterprise Development LP. |
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* |
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* This source code is part of the generic code that can be used |
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* by all the watchdog timer drivers. |
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* |
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* This part of the generic code takes care of the following |
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* misc device: /dev/watchdog. |
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* |
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* Based on source code of the following authors: |
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* Matt Domsch <[email protected]>, |
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* Rob Radez <[email protected]>, |
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* Rusty Lynch <[email protected]> |
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* Satyam Sharma <[email protected]> |
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* Randy Dunlap <[email protected]> |
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* |
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* Neither Alan Cox, CymruNet Ltd., Wim Van Sebroeck nor Iguana vzw. |
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* admit liability nor provide warranty for any of this software. |
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* This material is provided "AS-IS" and at no charge. |
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*/ |
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|
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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
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|
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#include <linux/cdev.h> /* For character device */ |
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#include <linux/errno.h> /* For the -ENODEV/... values */ |
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#include <linux/fs.h> /* For file operations */ |
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#include <linux/init.h> /* For __init/__exit/... */ |
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#include <linux/hrtimer.h> /* For hrtimers */ |
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#include <linux/kernel.h> /* For printk/panic/... */ |
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#include <linux/kthread.h> /* For kthread_work */ |
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#include <linux/miscdevice.h> /* For handling misc devices */ |
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#include <linux/module.h> /* For module stuff/... */ |
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#include <linux/mutex.h> /* For mutexes */ |
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#include <linux/slab.h> /* For memory functions */ |
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#include <linux/types.h> /* For standard types (like size_t) */ |
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#include <linux/watchdog.h> /* For watchdog specific items */ |
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#include <linux/uaccess.h> /* For copy_to_user/put_user/... */ |
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|
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#include "watchdog_core.h" |
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#include "watchdog_pretimeout.h" |
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|
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/* the dev_t structure to store the dynamically allocated watchdog devices */ |
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static dev_t watchdog_devt; |
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/* Reference to watchdog device behind /dev/watchdog */ |
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static struct watchdog_core_data *old_wd_data; |
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|
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static struct kthread_worker *watchdog_kworker; |
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|
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static bool handle_boot_enabled = |
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IS_ENABLED(CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED); |
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|
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static unsigned open_timeout = CONFIG_WATCHDOG_OPEN_TIMEOUT; |
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|
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static bool watchdog_past_open_deadline(struct watchdog_core_data *data) |
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{ |
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return ktime_after(ktime_get(), data->open_deadline); |
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} |
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|
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static void watchdog_set_open_deadline(struct watchdog_core_data *data) |
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{ |
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data->open_deadline = open_timeout ? |
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ktime_get() + ktime_set(open_timeout, 0) : KTIME_MAX; |
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} |
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|
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static inline bool watchdog_need_worker(struct watchdog_device *wdd) |
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{ |
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/* All variables in milli-seconds */ |
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unsigned int hm = wdd->max_hw_heartbeat_ms; |
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unsigned int t = wdd->timeout * 1000; |
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|
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/* |
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* A worker to generate heartbeat requests is needed if all of the |
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* following conditions are true. |
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* - Userspace activated the watchdog. |
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* - The driver provided a value for the maximum hardware timeout, and |
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* thus is aware that the framework supports generating heartbeat |
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* requests. |
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* - Userspace requests a longer timeout than the hardware can handle. |
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* |
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* Alternatively, if userspace has not opened the watchdog |
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* device, we take care of feeding the watchdog if it is |
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* running. |
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*/ |
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return (hm && watchdog_active(wdd) && t > hm) || |
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(t && !watchdog_active(wdd) && watchdog_hw_running(wdd)); |
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} |
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|
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static ktime_t watchdog_next_keepalive(struct watchdog_device *wdd) |
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{ |
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struct watchdog_core_data *wd_data = wdd->wd_data; |
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unsigned int timeout_ms = wdd->timeout * 1000; |
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ktime_t keepalive_interval; |
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ktime_t last_heartbeat, latest_heartbeat; |
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ktime_t virt_timeout; |
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unsigned int hw_heartbeat_ms; |
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|
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if (watchdog_active(wdd)) |
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virt_timeout = ktime_add(wd_data->last_keepalive, |
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ms_to_ktime(timeout_ms)); |
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else |
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virt_timeout = wd_data->open_deadline; |
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|
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hw_heartbeat_ms = min_not_zero(timeout_ms, wdd->max_hw_heartbeat_ms); |
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keepalive_interval = ms_to_ktime(hw_heartbeat_ms / 2); |
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|
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/* |
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* To ensure that the watchdog times out wdd->timeout seconds |
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* after the most recent ping from userspace, the last |
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* worker ping has to come in hw_heartbeat_ms before this timeout. |
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*/ |
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last_heartbeat = ktime_sub(virt_timeout, ms_to_ktime(hw_heartbeat_ms)); |
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latest_heartbeat = ktime_sub(last_heartbeat, ktime_get()); |
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if (ktime_before(latest_heartbeat, keepalive_interval)) |
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return latest_heartbeat; |
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return keepalive_interval; |
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} |
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static inline void watchdog_update_worker(struct watchdog_device *wdd) |
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{ |
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struct watchdog_core_data *wd_data = wdd->wd_data; |
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|
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if (watchdog_need_worker(wdd)) { |
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ktime_t t = watchdog_next_keepalive(wdd); |
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|
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if (t > 0) |
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hrtimer_start(&wd_data->timer, t, |
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HRTIMER_MODE_REL_HARD); |
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} else { |
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hrtimer_cancel(&wd_data->timer); |
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} |
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} |
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static int __watchdog_ping(struct watchdog_device *wdd) |
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{ |
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struct watchdog_core_data *wd_data = wdd->wd_data; |
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ktime_t earliest_keepalive, now; |
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int err; |
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earliest_keepalive = ktime_add(wd_data->last_hw_keepalive, |
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ms_to_ktime(wdd->min_hw_heartbeat_ms)); |
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now = ktime_get(); |
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|
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if (ktime_after(earliest_keepalive, now)) { |
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hrtimer_start(&wd_data->timer, |
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ktime_sub(earliest_keepalive, now), |
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HRTIMER_MODE_REL_HARD); |
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return 0; |
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} |
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wd_data->last_hw_keepalive = now; |
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|
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if (wdd->ops->ping) |
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err = wdd->ops->ping(wdd); /* ping the watchdog */ |
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else |
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err = wdd->ops->start(wdd); /* restart watchdog */ |
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if (err == 0) |
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watchdog_hrtimer_pretimeout_start(wdd); |
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watchdog_update_worker(wdd); |
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return err; |
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} |
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|
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/* |
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* watchdog_ping: ping the watchdog. |
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* @wdd: the watchdog device to ping |
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* |
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* The caller must hold wd_data->lock. |
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* |
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* If the watchdog has no own ping operation then it needs to be |
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* restarted via the start operation. This wrapper function does |
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* exactly that. |
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* We only ping when the watchdog device is running. |
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*/ |
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|
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static int watchdog_ping(struct watchdog_device *wdd) |
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{ |
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struct watchdog_core_data *wd_data = wdd->wd_data; |
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|
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if (!watchdog_active(wdd) && !watchdog_hw_running(wdd)) |
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return 0; |
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set_bit(_WDOG_KEEPALIVE, &wd_data->status); |
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wd_data->last_keepalive = ktime_get(); |
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return __watchdog_ping(wdd); |
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} |
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static bool watchdog_worker_should_ping(struct watchdog_core_data *wd_data) |
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{ |
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struct watchdog_device *wdd = wd_data->wdd; |
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if (!wdd) |
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return false; |
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if (watchdog_active(wdd)) |
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return true; |
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return watchdog_hw_running(wdd) && !watchdog_past_open_deadline(wd_data); |
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} |
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static void watchdog_ping_work(struct kthread_work *work) |
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{ |
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struct watchdog_core_data *wd_data; |
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wd_data = container_of(work, struct watchdog_core_data, work); |
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mutex_lock(&wd_data->lock); |
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if (watchdog_worker_should_ping(wd_data)) |
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__watchdog_ping(wd_data->wdd); |
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mutex_unlock(&wd_data->lock); |
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} |
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static enum hrtimer_restart watchdog_timer_expired(struct hrtimer *timer) |
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{ |
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struct watchdog_core_data *wd_data; |
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wd_data = container_of(timer, struct watchdog_core_data, timer); |
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kthread_queue_work(watchdog_kworker, &wd_data->work); |
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return HRTIMER_NORESTART; |
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} |
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|
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/* |
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* watchdog_start: wrapper to start the watchdog. |
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* @wdd: the watchdog device to start |
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* |
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* The caller must hold wd_data->lock. |
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* |
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* Start the watchdog if it is not active and mark it active. |
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* This function returns zero on success or a negative errno code for |
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* failure. |
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*/ |
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static int watchdog_start(struct watchdog_device *wdd) |
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{ |
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struct watchdog_core_data *wd_data = wdd->wd_data; |
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ktime_t started_at; |
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int err; |
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if (watchdog_active(wdd)) |
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return 0; |
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set_bit(_WDOG_KEEPALIVE, &wd_data->status); |
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started_at = ktime_get(); |
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if (watchdog_hw_running(wdd) && wdd->ops->ping) { |
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err = __watchdog_ping(wdd); |
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if (err == 0) { |
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set_bit(WDOG_ACTIVE, &wdd->status); |
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watchdog_hrtimer_pretimeout_start(wdd); |
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} |
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} else { |
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err = wdd->ops->start(wdd); |
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if (err == 0) { |
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set_bit(WDOG_ACTIVE, &wdd->status); |
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wd_data->last_keepalive = started_at; |
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wd_data->last_hw_keepalive = started_at; |
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watchdog_update_worker(wdd); |
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watchdog_hrtimer_pretimeout_start(wdd); |
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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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* watchdog_stop: wrapper to stop the watchdog. |
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* @wdd: the watchdog device to stop |
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* |
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* The caller must hold wd_data->lock. |
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* |
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* Stop the watchdog if it is still active and unmark it active. |
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* This function returns zero on success or a negative errno code for |
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* failure. |
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* If the 'nowayout' feature was set, the watchdog cannot be stopped. |
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*/ |
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static int watchdog_stop(struct watchdog_device *wdd) |
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{ |
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int err = 0; |
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if (!watchdog_active(wdd)) |
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return 0; |
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if (test_bit(WDOG_NO_WAY_OUT, &wdd->status)) { |
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pr_info("watchdog%d: nowayout prevents watchdog being stopped!\n", |
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wdd->id); |
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return -EBUSY; |
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} |
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if (wdd->ops->stop) { |
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clear_bit(WDOG_HW_RUNNING, &wdd->status); |
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err = wdd->ops->stop(wdd); |
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} else { |
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set_bit(WDOG_HW_RUNNING, &wdd->status); |
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} |
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if (err == 0) { |
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clear_bit(WDOG_ACTIVE, &wdd->status); |
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watchdog_update_worker(wdd); |
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watchdog_hrtimer_pretimeout_stop(wdd); |
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} |
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return err; |
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} |
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/* |
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* watchdog_get_status: wrapper to get the watchdog status |
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* @wdd: the watchdog device to get the status from |
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* |
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* The caller must hold wd_data->lock. |
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* |
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* Get the watchdog's status flags. |
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*/ |
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static unsigned int watchdog_get_status(struct watchdog_device *wdd) |
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{ |
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struct watchdog_core_data *wd_data = wdd->wd_data; |
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unsigned int status; |
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if (wdd->ops->status) |
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status = wdd->ops->status(wdd); |
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else |
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status = wdd->bootstatus & (WDIOF_CARDRESET | |
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WDIOF_OVERHEAT | |
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WDIOF_FANFAULT | |
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WDIOF_EXTERN1 | |
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WDIOF_EXTERN2 | |
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WDIOF_POWERUNDER | |
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WDIOF_POWEROVER); |
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if (test_bit(_WDOG_ALLOW_RELEASE, &wd_data->status)) |
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status |= WDIOF_MAGICCLOSE; |
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if (test_and_clear_bit(_WDOG_KEEPALIVE, &wd_data->status)) |
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status |= WDIOF_KEEPALIVEPING; |
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if (IS_ENABLED(CONFIG_WATCHDOG_HRTIMER_PRETIMEOUT)) |
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status |= WDIOF_PRETIMEOUT; |
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return status; |
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} |
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|
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/* |
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* watchdog_set_timeout: set the watchdog timer timeout |
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* @wdd: the watchdog device to set the timeout for |
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* @timeout: timeout to set in seconds |
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* |
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* The caller must hold wd_data->lock. |
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*/ |
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static int watchdog_set_timeout(struct watchdog_device *wdd, |
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unsigned int timeout) |
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{ |
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int err = 0; |
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if (!(wdd->info->options & WDIOF_SETTIMEOUT)) |
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return -EOPNOTSUPP; |
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if (watchdog_timeout_invalid(wdd, timeout)) |
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return -EINVAL; |
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if (wdd->ops->set_timeout) { |
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err = wdd->ops->set_timeout(wdd, timeout); |
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} else { |
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wdd->timeout = timeout; |
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/* Disable pretimeout if it doesn't fit the new timeout */ |
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if (wdd->pretimeout >= wdd->timeout) |
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wdd->pretimeout = 0; |
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} |
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watchdog_update_worker(wdd); |
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return err; |
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} |
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|
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/* |
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* watchdog_set_pretimeout: set the watchdog timer pretimeout |
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* @wdd: the watchdog device to set the timeout for |
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* @timeout: pretimeout to set in seconds |
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*/ |
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static int watchdog_set_pretimeout(struct watchdog_device *wdd, |
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unsigned int timeout) |
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{ |
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int err = 0; |
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|
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if (!watchdog_have_pretimeout(wdd)) |
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return -EOPNOTSUPP; |
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if (watchdog_pretimeout_invalid(wdd, timeout)) |
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return -EINVAL; |
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|
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if (wdd->ops->set_pretimeout && (wdd->info->options & WDIOF_PRETIMEOUT)) |
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err = wdd->ops->set_pretimeout(wdd, timeout); |
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else |
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wdd->pretimeout = timeout; |
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return err; |
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} |
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|
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/* |
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* watchdog_get_timeleft: wrapper to get the time left before a reboot |
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* @wdd: the watchdog device to get the remaining time from |
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* @timeleft: the time that's left |
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* |
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* The caller must hold wd_data->lock. |
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* |
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* Get the time before a watchdog will reboot (if not pinged). |
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*/ |
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static int watchdog_get_timeleft(struct watchdog_device *wdd, |
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unsigned int *timeleft) |
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{ |
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*timeleft = 0; |
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|
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if (!wdd->ops->get_timeleft) |
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return -EOPNOTSUPP; |
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*timeleft = wdd->ops->get_timeleft(wdd); |
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return 0; |
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} |
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#ifdef CONFIG_WATCHDOG_SYSFS |
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static ssize_t nowayout_show(struct device *dev, struct device_attribute *attr, |
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char *buf) |
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{ |
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struct watchdog_device *wdd = dev_get_drvdata(dev); |
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|
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return sysfs_emit(buf, "%d\n", !!test_bit(WDOG_NO_WAY_OUT, |
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&wdd->status)); |
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} |
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|
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static ssize_t nowayout_store(struct device *dev, struct device_attribute *attr, |
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const char *buf, size_t len) |
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{ |
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struct watchdog_device *wdd = dev_get_drvdata(dev); |
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unsigned int value; |
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int ret; |
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|
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ret = kstrtouint(buf, 0, &value); |
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if (ret) |
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return ret; |
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if (value > 1) |
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return -EINVAL; |
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/* nowayout cannot be disabled once set */ |
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if (test_bit(WDOG_NO_WAY_OUT, &wdd->status) && !value) |
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return -EPERM; |
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watchdog_set_nowayout(wdd, value); |
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return len; |
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} |
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static DEVICE_ATTR_RW(nowayout); |
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|
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static ssize_t status_show(struct device *dev, struct device_attribute *attr, |
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char *buf) |
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{ |
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struct watchdog_device *wdd = dev_get_drvdata(dev); |
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struct watchdog_core_data *wd_data = wdd->wd_data; |
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unsigned int status; |
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|
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mutex_lock(&wd_data->lock); |
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status = watchdog_get_status(wdd); |
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mutex_unlock(&wd_data->lock); |
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|
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return sysfs_emit(buf, "0x%x\n", status); |
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} |
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static DEVICE_ATTR_RO(status); |
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|
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static ssize_t bootstatus_show(struct device *dev, |
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struct device_attribute *attr, char *buf) |
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{ |
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struct watchdog_device *wdd = dev_get_drvdata(dev); |
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|
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return sysfs_emit(buf, "%u\n", wdd->bootstatus); |
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} |
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static DEVICE_ATTR_RO(bootstatus); |
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|
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static ssize_t timeleft_show(struct device *dev, struct device_attribute *attr, |
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char *buf) |
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{ |
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struct watchdog_device *wdd = dev_get_drvdata(dev); |
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struct watchdog_core_data *wd_data = wdd->wd_data; |
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ssize_t status; |
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unsigned int val; |
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|
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mutex_lock(&wd_data->lock); |
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status = watchdog_get_timeleft(wdd, &val); |
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mutex_unlock(&wd_data->lock); |
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if (!status) |
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status = sysfs_emit(buf, "%u\n", val); |
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|
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return status; |
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} |
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static DEVICE_ATTR_RO(timeleft); |
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|
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static ssize_t timeout_show(struct device *dev, struct device_attribute *attr, |
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char *buf) |
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{ |
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struct watchdog_device *wdd = dev_get_drvdata(dev); |
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|
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return sysfs_emit(buf, "%u\n", wdd->timeout); |
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} |
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static DEVICE_ATTR_RO(timeout); |
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|
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static ssize_t min_timeout_show(struct device *dev, |
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struct device_attribute *attr, char *buf) |
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{ |
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struct watchdog_device *wdd = dev_get_drvdata(dev); |
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|
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return sysfs_emit(buf, "%u\n", wdd->min_timeout); |
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} |
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static DEVICE_ATTR_RO(min_timeout); |
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|
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static ssize_t max_timeout_show(struct device *dev, |
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struct device_attribute *attr, char *buf) |
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{ |
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struct watchdog_device *wdd = dev_get_drvdata(dev); |
|
|
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return sysfs_emit(buf, "%u\n", wdd->max_timeout); |
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} |
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static DEVICE_ATTR_RO(max_timeout); |
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|
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static ssize_t pretimeout_show(struct device *dev, |
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struct device_attribute *attr, char *buf) |
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{ |
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struct watchdog_device *wdd = dev_get_drvdata(dev); |
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|
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return sysfs_emit(buf, "%u\n", wdd->pretimeout); |
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} |
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static DEVICE_ATTR_RO(pretimeout); |
|
|
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static ssize_t identity_show(struct device *dev, struct device_attribute *attr, |
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char *buf) |
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{ |
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struct watchdog_device *wdd = dev_get_drvdata(dev); |
|
|
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return sysfs_emit(buf, "%s\n", wdd->info->identity); |
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} |
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static DEVICE_ATTR_RO(identity); |
|
|
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static ssize_t state_show(struct device *dev, struct device_attribute *attr, |
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char *buf) |
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{ |
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struct watchdog_device *wdd = dev_get_drvdata(dev); |
|
|
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if (watchdog_active(wdd)) |
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return sysfs_emit(buf, "active\n"); |
|
|
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return sysfs_emit(buf, "inactive\n"); |
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} |
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static DEVICE_ATTR_RO(state); |
|
|
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static ssize_t pretimeout_available_governors_show(struct device *dev, |
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struct device_attribute *attr, char *buf) |
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{ |
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return watchdog_pretimeout_available_governors_get(buf); |
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} |
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static DEVICE_ATTR_RO(pretimeout_available_governors); |
|
|
|
static ssize_t pretimeout_governor_show(struct device *dev, |
|
struct device_attribute *attr, |
|
char *buf) |
|
{ |
|
struct watchdog_device *wdd = dev_get_drvdata(dev); |
|
|
|
return watchdog_pretimeout_governor_get(wdd, buf); |
|
} |
|
|
|
static ssize_t pretimeout_governor_store(struct device *dev, |
|
struct device_attribute *attr, |
|
const char *buf, size_t count) |
|
{ |
|
struct watchdog_device *wdd = dev_get_drvdata(dev); |
|
int ret = watchdog_pretimeout_governor_set(wdd, buf); |
|
|
|
if (!ret) |
|
ret = count; |
|
|
|
return ret; |
|
} |
|
static DEVICE_ATTR_RW(pretimeout_governor); |
|
|
|
static umode_t wdt_is_visible(struct kobject *kobj, struct attribute *attr, |
|
int n) |
|
{ |
|
struct device *dev = kobj_to_dev(kobj); |
|
struct watchdog_device *wdd = dev_get_drvdata(dev); |
|
umode_t mode = attr->mode; |
|
|
|
if (attr == &dev_attr_timeleft.attr && !wdd->ops->get_timeleft) |
|
mode = 0; |
|
else if (attr == &dev_attr_pretimeout.attr && !watchdog_have_pretimeout(wdd)) |
|
mode = 0; |
|
else if ((attr == &dev_attr_pretimeout_governor.attr || |
|
attr == &dev_attr_pretimeout_available_governors.attr) && |
|
(!watchdog_have_pretimeout(wdd) || !IS_ENABLED(CONFIG_WATCHDOG_PRETIMEOUT_GOV))) |
|
mode = 0; |
|
|
|
return mode; |
|
} |
|
static struct attribute *wdt_attrs[] = { |
|
&dev_attr_state.attr, |
|
&dev_attr_identity.attr, |
|
&dev_attr_timeout.attr, |
|
&dev_attr_min_timeout.attr, |
|
&dev_attr_max_timeout.attr, |
|
&dev_attr_pretimeout.attr, |
|
&dev_attr_timeleft.attr, |
|
&dev_attr_bootstatus.attr, |
|
&dev_attr_status.attr, |
|
&dev_attr_nowayout.attr, |
|
&dev_attr_pretimeout_governor.attr, |
|
&dev_attr_pretimeout_available_governors.attr, |
|
NULL, |
|
}; |
|
|
|
static const struct attribute_group wdt_group = { |
|
.attrs = wdt_attrs, |
|
.is_visible = wdt_is_visible, |
|
}; |
|
__ATTRIBUTE_GROUPS(wdt); |
|
#else |
|
#define wdt_groups NULL |
|
#endif |
|
|
|
/* |
|
* watchdog_ioctl_op: call the watchdog drivers ioctl op if defined |
|
* @wdd: the watchdog device to do the ioctl on |
|
* @cmd: watchdog command |
|
* @arg: argument pointer |
|
* |
|
* The caller must hold wd_data->lock. |
|
*/ |
|
|
|
static int watchdog_ioctl_op(struct watchdog_device *wdd, unsigned int cmd, |
|
unsigned long arg) |
|
{ |
|
if (!wdd->ops->ioctl) |
|
return -ENOIOCTLCMD; |
|
|
|
return wdd->ops->ioctl(wdd, cmd, arg); |
|
} |
|
|
|
/* |
|
* watchdog_write: writes to the watchdog. |
|
* @file: file from VFS |
|
* @data: user address of data |
|
* @len: length of data |
|
* @ppos: pointer to the file offset |
|
* |
|
* A write to a watchdog device is defined as a keepalive ping. |
|
* Writing the magic 'V' sequence allows the next close to turn |
|
* off the watchdog (if 'nowayout' is not set). |
|
*/ |
|
|
|
static ssize_t watchdog_write(struct file *file, const char __user *data, |
|
size_t len, loff_t *ppos) |
|
{ |
|
struct watchdog_core_data *wd_data = file->private_data; |
|
struct watchdog_device *wdd; |
|
int err; |
|
size_t i; |
|
char c; |
|
|
|
if (len == 0) |
|
return 0; |
|
|
|
/* |
|
* Note: just in case someone wrote the magic character |
|
* five months ago... |
|
*/ |
|
clear_bit(_WDOG_ALLOW_RELEASE, &wd_data->status); |
|
|
|
/* scan to see whether or not we got the magic character */ |
|
for (i = 0; i != len; i++) { |
|
if (get_user(c, data + i)) |
|
return -EFAULT; |
|
if (c == 'V') |
|
set_bit(_WDOG_ALLOW_RELEASE, &wd_data->status); |
|
} |
|
|
|
/* someone wrote to us, so we send the watchdog a keepalive ping */ |
|
|
|
err = -ENODEV; |
|
mutex_lock(&wd_data->lock); |
|
wdd = wd_data->wdd; |
|
if (wdd) |
|
err = watchdog_ping(wdd); |
|
mutex_unlock(&wd_data->lock); |
|
|
|
if (err < 0) |
|
return err; |
|
|
|
return len; |
|
} |
|
|
|
/* |
|
* watchdog_ioctl: handle the different ioctl's for the watchdog device. |
|
* @file: file handle to the device |
|
* @cmd: watchdog command |
|
* @arg: argument pointer |
|
* |
|
* The watchdog API defines a common set of functions for all watchdogs |
|
* according to their available features. |
|
*/ |
|
|
|
static long watchdog_ioctl(struct file *file, unsigned int cmd, |
|
unsigned long arg) |
|
{ |
|
struct watchdog_core_data *wd_data = file->private_data; |
|
void __user *argp = (void __user *)arg; |
|
struct watchdog_device *wdd; |
|
int __user *p = argp; |
|
unsigned int val; |
|
int err; |
|
|
|
mutex_lock(&wd_data->lock); |
|
|
|
wdd = wd_data->wdd; |
|
if (!wdd) { |
|
err = -ENODEV; |
|
goto out_ioctl; |
|
} |
|
|
|
err = watchdog_ioctl_op(wdd, cmd, arg); |
|
if (err != -ENOIOCTLCMD) |
|
goto out_ioctl; |
|
|
|
switch (cmd) { |
|
case WDIOC_GETSUPPORT: |
|
err = copy_to_user(argp, wdd->info, |
|
sizeof(struct watchdog_info)) ? -EFAULT : 0; |
|
break; |
|
case WDIOC_GETSTATUS: |
|
val = watchdog_get_status(wdd); |
|
err = put_user(val, p); |
|
break; |
|
case WDIOC_GETBOOTSTATUS: |
|
err = put_user(wdd->bootstatus, p); |
|
break; |
|
case WDIOC_SETOPTIONS: |
|
if (get_user(val, p)) { |
|
err = -EFAULT; |
|
break; |
|
} |
|
if (val & WDIOS_DISABLECARD) { |
|
err = watchdog_stop(wdd); |
|
if (err < 0) |
|
break; |
|
} |
|
if (val & WDIOS_ENABLECARD) |
|
err = watchdog_start(wdd); |
|
break; |
|
case WDIOC_KEEPALIVE: |
|
if (!(wdd->info->options & WDIOF_KEEPALIVEPING)) { |
|
err = -EOPNOTSUPP; |
|
break; |
|
} |
|
err = watchdog_ping(wdd); |
|
break; |
|
case WDIOC_SETTIMEOUT: |
|
if (get_user(val, p)) { |
|
err = -EFAULT; |
|
break; |
|
} |
|
err = watchdog_set_timeout(wdd, val); |
|
if (err < 0) |
|
break; |
|
/* If the watchdog is active then we send a keepalive ping |
|
* to make sure that the watchdog keep's running (and if |
|
* possible that it takes the new timeout) */ |
|
err = watchdog_ping(wdd); |
|
if (err < 0) |
|
break; |
|
fallthrough; |
|
case WDIOC_GETTIMEOUT: |
|
/* timeout == 0 means that we don't know the timeout */ |
|
if (wdd->timeout == 0) { |
|
err = -EOPNOTSUPP; |
|
break; |
|
} |
|
err = put_user(wdd->timeout, p); |
|
break; |
|
case WDIOC_GETTIMELEFT: |
|
err = watchdog_get_timeleft(wdd, &val); |
|
if (err < 0) |
|
break; |
|
err = put_user(val, p); |
|
break; |
|
case WDIOC_SETPRETIMEOUT: |
|
if (get_user(val, p)) { |
|
err = -EFAULT; |
|
break; |
|
} |
|
err = watchdog_set_pretimeout(wdd, val); |
|
break; |
|
case WDIOC_GETPRETIMEOUT: |
|
err = put_user(wdd->pretimeout, p); |
|
break; |
|
default: |
|
err = -ENOTTY; |
|
break; |
|
} |
|
|
|
out_ioctl: |
|
mutex_unlock(&wd_data->lock); |
|
return err; |
|
} |
|
|
|
/* |
|
* watchdog_open: open the /dev/watchdog* devices. |
|
* @inode: inode of device |
|
* @file: file handle to device |
|
* |
|
* When the /dev/watchdog* device gets opened, we start the watchdog. |
|
* Watch out: the /dev/watchdog device is single open, so we make sure |
|
* it can only be opened once. |
|
*/ |
|
|
|
static int watchdog_open(struct inode *inode, struct file *file) |
|
{ |
|
struct watchdog_core_data *wd_data; |
|
struct watchdog_device *wdd; |
|
bool hw_running; |
|
int err; |
|
|
|
/* Get the corresponding watchdog device */ |
|
if (imajor(inode) == MISC_MAJOR) |
|
wd_data = old_wd_data; |
|
else |
|
wd_data = container_of(inode->i_cdev, struct watchdog_core_data, |
|
cdev); |
|
|
|
/* the watchdog is single open! */ |
|
if (test_and_set_bit(_WDOG_DEV_OPEN, &wd_data->status)) |
|
return -EBUSY; |
|
|
|
wdd = wd_data->wdd; |
|
|
|
/* |
|
* If the /dev/watchdog device is open, we don't want the module |
|
* to be unloaded. |
|
*/ |
|
hw_running = watchdog_hw_running(wdd); |
|
if (!hw_running && !try_module_get(wdd->ops->owner)) { |
|
err = -EBUSY; |
|
goto out_clear; |
|
} |
|
|
|
err = watchdog_start(wdd); |
|
if (err < 0) |
|
goto out_mod; |
|
|
|
file->private_data = wd_data; |
|
|
|
if (!hw_running) |
|
get_device(&wd_data->dev); |
|
|
|
/* |
|
* open_timeout only applies for the first open from |
|
* userspace. Set open_deadline to infinity so that the kernel |
|
* will take care of an always-running hardware watchdog in |
|
* case the device gets magic-closed or WDIOS_DISABLECARD is |
|
* applied. |
|
*/ |
|
wd_data->open_deadline = KTIME_MAX; |
|
|
|
/* dev/watchdog is a virtual (and thus non-seekable) filesystem */ |
|
return stream_open(inode, file); |
|
|
|
out_mod: |
|
module_put(wd_data->wdd->ops->owner); |
|
out_clear: |
|
clear_bit(_WDOG_DEV_OPEN, &wd_data->status); |
|
return err; |
|
} |
|
|
|
static void watchdog_core_data_release(struct device *dev) |
|
{ |
|
struct watchdog_core_data *wd_data; |
|
|
|
wd_data = container_of(dev, struct watchdog_core_data, dev); |
|
|
|
kfree(wd_data); |
|
} |
|
|
|
/* |
|
* watchdog_release: release the watchdog device. |
|
* @inode: inode of device |
|
* @file: file handle to device |
|
* |
|
* This is the code for when /dev/watchdog gets closed. We will only |
|
* stop the watchdog when we have received the magic char (and nowayout |
|
* was not set), else the watchdog will keep running. |
|
*/ |
|
|
|
static int watchdog_release(struct inode *inode, struct file *file) |
|
{ |
|
struct watchdog_core_data *wd_data = file->private_data; |
|
struct watchdog_device *wdd; |
|
int err = -EBUSY; |
|
bool running; |
|
|
|
mutex_lock(&wd_data->lock); |
|
|
|
wdd = wd_data->wdd; |
|
if (!wdd) |
|
goto done; |
|
|
|
/* |
|
* We only stop the watchdog if we received the magic character |
|
* or if WDIOF_MAGICCLOSE is not set. If nowayout was set then |
|
* watchdog_stop will fail. |
|
*/ |
|
if (!watchdog_active(wdd)) |
|
err = 0; |
|
else if (test_and_clear_bit(_WDOG_ALLOW_RELEASE, &wd_data->status) || |
|
!(wdd->info->options & WDIOF_MAGICCLOSE)) |
|
err = watchdog_stop(wdd); |
|
|
|
/* If the watchdog was not stopped, send a keepalive ping */ |
|
if (err < 0) { |
|
pr_crit("watchdog%d: watchdog did not stop!\n", wdd->id); |
|
watchdog_ping(wdd); |
|
} |
|
|
|
watchdog_update_worker(wdd); |
|
|
|
/* make sure that /dev/watchdog can be re-opened */ |
|
clear_bit(_WDOG_DEV_OPEN, &wd_data->status); |
|
|
|
done: |
|
running = wdd && watchdog_hw_running(wdd); |
|
mutex_unlock(&wd_data->lock); |
|
/* |
|
* Allow the owner module to be unloaded again unless the watchdog |
|
* is still running. If the watchdog is still running, it can not |
|
* be stopped, and its driver must not be unloaded. |
|
*/ |
|
if (!running) { |
|
module_put(wd_data->cdev.owner); |
|
put_device(&wd_data->dev); |
|
} |
|
return 0; |
|
} |
|
|
|
static const struct file_operations watchdog_fops = { |
|
.owner = THIS_MODULE, |
|
.write = watchdog_write, |
|
.unlocked_ioctl = watchdog_ioctl, |
|
.compat_ioctl = compat_ptr_ioctl, |
|
.open = watchdog_open, |
|
.release = watchdog_release, |
|
}; |
|
|
|
static struct miscdevice watchdog_miscdev = { |
|
.minor = WATCHDOG_MINOR, |
|
.name = "watchdog", |
|
.fops = &watchdog_fops, |
|
}; |
|
|
|
static struct class watchdog_class = { |
|
.name = "watchdog", |
|
.owner = THIS_MODULE, |
|
.dev_groups = wdt_groups, |
|
}; |
|
|
|
/* |
|
* watchdog_cdev_register: register watchdog character device |
|
* @wdd: watchdog device |
|
* |
|
* Register a watchdog character device including handling the legacy |
|
* /dev/watchdog node. /dev/watchdog is actually a miscdevice and |
|
* thus we set it up like that. |
|
*/ |
|
|
|
static int watchdog_cdev_register(struct watchdog_device *wdd) |
|
{ |
|
struct watchdog_core_data *wd_data; |
|
int err; |
|
|
|
wd_data = kzalloc(sizeof(struct watchdog_core_data), GFP_KERNEL); |
|
if (!wd_data) |
|
return -ENOMEM; |
|
mutex_init(&wd_data->lock); |
|
|
|
wd_data->wdd = wdd; |
|
wdd->wd_data = wd_data; |
|
|
|
if (IS_ERR_OR_NULL(watchdog_kworker)) { |
|
kfree(wd_data); |
|
return -ENODEV; |
|
} |
|
|
|
device_initialize(&wd_data->dev); |
|
wd_data->dev.devt = MKDEV(MAJOR(watchdog_devt), wdd->id); |
|
wd_data->dev.class = &watchdog_class; |
|
wd_data->dev.parent = wdd->parent; |
|
wd_data->dev.groups = wdd->groups; |
|
wd_data->dev.release = watchdog_core_data_release; |
|
dev_set_drvdata(&wd_data->dev, wdd); |
|
dev_set_name(&wd_data->dev, "watchdog%d", wdd->id); |
|
|
|
kthread_init_work(&wd_data->work, watchdog_ping_work); |
|
hrtimer_init(&wd_data->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD); |
|
wd_data->timer.function = watchdog_timer_expired; |
|
watchdog_hrtimer_pretimeout_init(wdd); |
|
|
|
if (wdd->id == 0) { |
|
old_wd_data = wd_data; |
|
watchdog_miscdev.parent = wdd->parent; |
|
err = misc_register(&watchdog_miscdev); |
|
if (err != 0) { |
|
pr_err("%s: cannot register miscdev on minor=%d (err=%d).\n", |
|
wdd->info->identity, WATCHDOG_MINOR, err); |
|
if (err == -EBUSY) |
|
pr_err("%s: a legacy watchdog module is probably present.\n", |
|
wdd->info->identity); |
|
old_wd_data = NULL; |
|
put_device(&wd_data->dev); |
|
return err; |
|
} |
|
} |
|
|
|
/* Fill in the data structures */ |
|
cdev_init(&wd_data->cdev, &watchdog_fops); |
|
|
|
/* Add the device */ |
|
err = cdev_device_add(&wd_data->cdev, &wd_data->dev); |
|
if (err) { |
|
pr_err("watchdog%d unable to add device %d:%d\n", |
|
wdd->id, MAJOR(watchdog_devt), wdd->id); |
|
if (wdd->id == 0) { |
|
misc_deregister(&watchdog_miscdev); |
|
old_wd_data = NULL; |
|
put_device(&wd_data->dev); |
|
} |
|
return err; |
|
} |
|
|
|
wd_data->cdev.owner = wdd->ops->owner; |
|
|
|
/* Record time of most recent heartbeat as 'just before now'. */ |
|
wd_data->last_hw_keepalive = ktime_sub(ktime_get(), 1); |
|
watchdog_set_open_deadline(wd_data); |
|
|
|
/* |
|
* If the watchdog is running, prevent its driver from being unloaded, |
|
* and schedule an immediate ping. |
|
*/ |
|
if (watchdog_hw_running(wdd)) { |
|
__module_get(wdd->ops->owner); |
|
get_device(&wd_data->dev); |
|
if (handle_boot_enabled) |
|
hrtimer_start(&wd_data->timer, 0, |
|
HRTIMER_MODE_REL_HARD); |
|
else |
|
pr_info("watchdog%d running and kernel based pre-userspace handler disabled\n", |
|
wdd->id); |
|
} |
|
|
|
return 0; |
|
} |
|
|
|
/* |
|
* watchdog_cdev_unregister: unregister watchdog character device |
|
* @watchdog: watchdog device |
|
* |
|
* Unregister watchdog character device and if needed the legacy |
|
* /dev/watchdog device. |
|
*/ |
|
|
|
static void watchdog_cdev_unregister(struct watchdog_device *wdd) |
|
{ |
|
struct watchdog_core_data *wd_data = wdd->wd_data; |
|
|
|
cdev_device_del(&wd_data->cdev, &wd_data->dev); |
|
if (wdd->id == 0) { |
|
misc_deregister(&watchdog_miscdev); |
|
old_wd_data = NULL; |
|
} |
|
|
|
if (watchdog_active(wdd) && |
|
test_bit(WDOG_STOP_ON_UNREGISTER, &wdd->status)) { |
|
watchdog_stop(wdd); |
|
} |
|
|
|
watchdog_hrtimer_pretimeout_stop(wdd); |
|
|
|
mutex_lock(&wd_data->lock); |
|
wd_data->wdd = NULL; |
|
wdd->wd_data = NULL; |
|
mutex_unlock(&wd_data->lock); |
|
|
|
hrtimer_cancel(&wd_data->timer); |
|
kthread_cancel_work_sync(&wd_data->work); |
|
|
|
put_device(&wd_data->dev); |
|
} |
|
|
|
/* |
|
* watchdog_dev_register: register a watchdog device |
|
* @wdd: watchdog device |
|
* |
|
* Register a watchdog device including handling the legacy |
|
* /dev/watchdog node. /dev/watchdog is actually a miscdevice and |
|
* thus we set it up like that. |
|
*/ |
|
|
|
int watchdog_dev_register(struct watchdog_device *wdd) |
|
{ |
|
int ret; |
|
|
|
ret = watchdog_cdev_register(wdd); |
|
if (ret) |
|
return ret; |
|
|
|
ret = watchdog_register_pretimeout(wdd); |
|
if (ret) |
|
watchdog_cdev_unregister(wdd); |
|
|
|
return ret; |
|
} |
|
|
|
/* |
|
* watchdog_dev_unregister: unregister a watchdog device |
|
* @watchdog: watchdog device |
|
* |
|
* Unregister watchdog device and if needed the legacy |
|
* /dev/watchdog device. |
|
*/ |
|
|
|
void watchdog_dev_unregister(struct watchdog_device *wdd) |
|
{ |
|
watchdog_unregister_pretimeout(wdd); |
|
watchdog_cdev_unregister(wdd); |
|
} |
|
|
|
/* |
|
* watchdog_set_last_hw_keepalive: set last HW keepalive time for watchdog |
|
* @wdd: watchdog device |
|
* @last_ping_ms: time since last HW heartbeat |
|
* |
|
* Adjusts the last known HW keepalive time for a watchdog timer. |
|
* This is needed if the watchdog is already running when the probe |
|
* function is called, and it can't be pinged immediately. This |
|
* function must be called immediately after watchdog registration, |
|
* and min_hw_heartbeat_ms must be set for this to be useful. |
|
*/ |
|
int watchdog_set_last_hw_keepalive(struct watchdog_device *wdd, |
|
unsigned int last_ping_ms) |
|
{ |
|
struct watchdog_core_data *wd_data; |
|
ktime_t now; |
|
|
|
if (!wdd) |
|
return -EINVAL; |
|
|
|
wd_data = wdd->wd_data; |
|
|
|
now = ktime_get(); |
|
|
|
wd_data->last_hw_keepalive = ktime_sub(now, ms_to_ktime(last_ping_ms)); |
|
|
|
if (watchdog_hw_running(wdd) && handle_boot_enabled) |
|
return __watchdog_ping(wdd); |
|
|
|
return 0; |
|
} |
|
EXPORT_SYMBOL_GPL(watchdog_set_last_hw_keepalive); |
|
|
|
/* |
|
* watchdog_dev_init: init dev part of watchdog core |
|
* |
|
* Allocate a range of chardev nodes to use for watchdog devices |
|
*/ |
|
|
|
int __init watchdog_dev_init(void) |
|
{ |
|
int err; |
|
|
|
watchdog_kworker = kthread_create_worker(0, "watchdogd"); |
|
if (IS_ERR(watchdog_kworker)) { |
|
pr_err("Failed to create watchdog kworker\n"); |
|
return PTR_ERR(watchdog_kworker); |
|
} |
|
sched_set_fifo(watchdog_kworker->task); |
|
|
|
err = class_register(&watchdog_class); |
|
if (err < 0) { |
|
pr_err("couldn't register class\n"); |
|
goto err_register; |
|
} |
|
|
|
err = alloc_chrdev_region(&watchdog_devt, 0, MAX_DOGS, "watchdog"); |
|
if (err < 0) { |
|
pr_err("watchdog: unable to allocate char dev region\n"); |
|
goto err_alloc; |
|
} |
|
|
|
return 0; |
|
|
|
err_alloc: |
|
class_unregister(&watchdog_class); |
|
err_register: |
|
kthread_destroy_worker(watchdog_kworker); |
|
return err; |
|
} |
|
|
|
/* |
|
* watchdog_dev_exit: exit dev part of watchdog core |
|
* |
|
* Release the range of chardev nodes used for watchdog devices |
|
*/ |
|
|
|
void __exit watchdog_dev_exit(void) |
|
{ |
|
unregister_chrdev_region(watchdog_devt, MAX_DOGS); |
|
class_unregister(&watchdog_class); |
|
kthread_destroy_worker(watchdog_kworker); |
|
} |
|
|
|
int watchdog_dev_suspend(struct watchdog_device *wdd) |
|
{ |
|
struct watchdog_core_data *wd_data = wdd->wd_data; |
|
int ret = 0; |
|
|
|
if (!wdd->wd_data) |
|
return -ENODEV; |
|
|
|
/* ping for the last time before suspend */ |
|
mutex_lock(&wd_data->lock); |
|
if (watchdog_worker_should_ping(wd_data)) |
|
ret = __watchdog_ping(wd_data->wdd); |
|
mutex_unlock(&wd_data->lock); |
|
|
|
if (ret) |
|
return ret; |
|
|
|
/* |
|
* make sure that watchdog worker will not kick in when the wdog is |
|
* suspended |
|
*/ |
|
hrtimer_cancel(&wd_data->timer); |
|
kthread_cancel_work_sync(&wd_data->work); |
|
|
|
return 0; |
|
} |
|
|
|
int watchdog_dev_resume(struct watchdog_device *wdd) |
|
{ |
|
struct watchdog_core_data *wd_data = wdd->wd_data; |
|
int ret = 0; |
|
|
|
if (!wdd->wd_data) |
|
return -ENODEV; |
|
|
|
/* |
|
* __watchdog_ping will also retrigger hrtimer and therefore restore the |
|
* ping worker if needed. |
|
*/ |
|
mutex_lock(&wd_data->lock); |
|
if (watchdog_worker_should_ping(wd_data)) |
|
ret = __watchdog_ping(wd_data->wdd); |
|
mutex_unlock(&wd_data->lock); |
|
|
|
return ret; |
|
} |
|
|
|
module_param(handle_boot_enabled, bool, 0444); |
|
MODULE_PARM_DESC(handle_boot_enabled, |
|
"Watchdog core auto-updates boot enabled watchdogs before userspace takes over (default=" |
|
__MODULE_STRING(IS_ENABLED(CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED)) ")"); |
|
|
|
module_param(open_timeout, uint, 0644); |
|
MODULE_PARM_DESC(open_timeout, |
|
"Maximum time (in seconds, 0 means infinity) for userspace to take over a running watchdog (default=" |
|
__MODULE_STRING(CONFIG_WATCHDOG_OPEN_TIMEOUT) ")");
|
|
|