| // SPDX-License-Identifier: GPL-2.0+ |
| /* |
| * watchdog_dev.c |
| * |
| * (c) Copyright 2008-2011 Alan Cox <alan@lxorguk.ukuu.org.uk>, |
| * All Rights Reserved. |
| * |
| * (c) Copyright 2008-2011 Wim Van Sebroeck <wim@iguana.be>. |
| * |
| * (c) Copyright 2021 Hewlett Packard Enterprise Development LP. |
| * |
| * This source code is part of the generic code that can be used |
| * by all the watchdog timer drivers. |
| * |
| * This part of the generic code takes care of the following |
| * misc device: /dev/watchdog. |
| * |
| * Based on source code of the following authors: |
| * Matt Domsch <Matt_Domsch@dell.com>, |
| * Rob Radez <rob@osinvestor.com>, |
| * Rusty Lynch <rusty@linux.co.intel.com> |
| * Satyam Sharma <satyam@infradead.org> |
| * Randy Dunlap <randy.dunlap@oracle.com> |
| * |
| * Neither Alan Cox, CymruNet Ltd., Wim Van Sebroeck nor Iguana vzw. |
| * admit liability nor provide warranty for any of this software. |
| * This material is provided "AS-IS" and at no charge. |
| */ |
| |
| #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt |
| |
| #include <linux/cdev.h> /* For character device */ |
| #include <linux/errno.h> /* For the -ENODEV/... values */ |
| #include <linux/fs.h> /* For file operations */ |
| #include <linux/init.h> /* For __init/__exit/... */ |
| #include <linux/hrtimer.h> /* For hrtimers */ |
| #include <linux/kernel.h> /* For printk/panic/... */ |
| #include <linux/kthread.h> /* For kthread_work */ |
| #include <linux/miscdevice.h> /* For handling misc devices */ |
| #include <linux/module.h> /* For module stuff/... */ |
| #include <linux/mutex.h> /* For mutexes */ |
| #include <linux/slab.h> /* For memory functions */ |
| #include <linux/types.h> /* For standard types (like size_t) */ |
| #include <linux/watchdog.h> /* For watchdog specific items */ |
| #include <linux/uaccess.h> /* For copy_to_user/put_user/... */ |
| |
| #include "watchdog_core.h" |
| #include "watchdog_pretimeout.h" |
| |
| /* the dev_t structure to store the dynamically allocated watchdog devices */ |
| static dev_t watchdog_devt; |
| /* Reference to watchdog device behind /dev/watchdog */ |
| static struct watchdog_core_data *old_wd_data; |
| |
| static struct kthread_worker *watchdog_kworker; |
| |
| static bool handle_boot_enabled = |
| IS_ENABLED(CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED); |
| |
| static unsigned open_timeout = CONFIG_WATCHDOG_OPEN_TIMEOUT; |
| |
| static bool watchdog_past_open_deadline(struct watchdog_core_data *data) |
| { |
| return ktime_after(ktime_get(), data->open_deadline); |
| } |
| |
| static void watchdog_set_open_deadline(struct watchdog_core_data *data) |
| { |
| data->open_deadline = open_timeout ? |
| ktime_get() + ktime_set(open_timeout, 0) : KTIME_MAX; |
| } |
| |
| static inline bool watchdog_need_worker(struct watchdog_device *wdd) |
| { |
| /* All variables in milli-seconds */ |
| unsigned int hm = wdd->max_hw_heartbeat_ms; |
| unsigned int t = wdd->timeout * 1000; |
| |
| /* |
| * A worker to generate heartbeat requests is needed if all of the |
| * following conditions are true. |
| * - Userspace activated the watchdog. |
| * - The driver provided a value for the maximum hardware timeout, and |
| * thus is aware that the framework supports generating heartbeat |
| * requests. |
| * - Userspace requests a longer timeout than the hardware can handle. |
| * |
| * Alternatively, if userspace has not opened the watchdog |
| * device, we take care of feeding the watchdog if it is |
| * running. |
| */ |
| return (hm && watchdog_active(wdd) && t > hm) || |
| (t && !watchdog_active(wdd) && watchdog_hw_running(wdd)); |
| } |
| |
| static ktime_t watchdog_next_keepalive(struct watchdog_device *wdd) |
| { |
| struct watchdog_core_data *wd_data = wdd->wd_data; |
| unsigned int timeout_ms = wdd->timeout * 1000; |
| ktime_t keepalive_interval; |
| ktime_t last_heartbeat, latest_heartbeat; |
| ktime_t virt_timeout; |
| unsigned int hw_heartbeat_ms; |
| |
| if (watchdog_active(wdd)) |
| virt_timeout = ktime_add(wd_data->last_keepalive, |
| ms_to_ktime(timeout_ms)); |
| else |
| virt_timeout = wd_data->open_deadline; |
| |
| hw_heartbeat_ms = min_not_zero(timeout_ms, wdd->max_hw_heartbeat_ms); |
| keepalive_interval = ms_to_ktime(hw_heartbeat_ms / 2); |
| |
| /* |
| * To ensure that the watchdog times out wdd->timeout seconds |
| * after the most recent ping from userspace, the last |
| * worker ping has to come in hw_heartbeat_ms before this timeout. |
| */ |
| last_heartbeat = ktime_sub(virt_timeout, ms_to_ktime(hw_heartbeat_ms)); |
| latest_heartbeat = ktime_sub(last_heartbeat, ktime_get()); |
| if (ktime_before(latest_heartbeat, keepalive_interval)) |
| return latest_heartbeat; |
| return keepalive_interval; |
| } |
| |
| static inline void watchdog_update_worker(struct watchdog_device *wdd) |
| { |
| struct watchdog_core_data *wd_data = wdd->wd_data; |
| |
| if (watchdog_need_worker(wdd)) { |
| ktime_t t = watchdog_next_keepalive(wdd); |
| |
| if (t > 0) |
| hrtimer_start(&wd_data->timer, t, |
| HRTIMER_MODE_REL_HARD); |
| } else { |
| hrtimer_cancel(&wd_data->timer); |
| } |
| } |
| |
| static int __watchdog_ping(struct watchdog_device *wdd) |
| { |
| struct watchdog_core_data *wd_data = wdd->wd_data; |
| ktime_t earliest_keepalive, now; |
| int err; |
| |
| earliest_keepalive = ktime_add(wd_data->last_hw_keepalive, |
| ms_to_ktime(wdd->min_hw_heartbeat_ms)); |
| now = ktime_get(); |
| |
| if (ktime_after(earliest_keepalive, now)) { |
| hrtimer_start(&wd_data->timer, |
| ktime_sub(earliest_keepalive, now), |
| HRTIMER_MODE_REL_HARD); |
| return 0; |
| } |
| |
| wd_data->last_hw_keepalive = now; |
| |
| if (wdd->ops->ping) |
| err = wdd->ops->ping(wdd); /* ping the watchdog */ |
| else |
| err = wdd->ops->start(wdd); /* restart watchdog */ |
| |
| if (err == 0) |
| watchdog_hrtimer_pretimeout_start(wdd); |
| |
| watchdog_update_worker(wdd); |
| |
| return err; |
| } |
| |
| /* |
| * watchdog_ping: ping the watchdog. |
| * @wdd: the watchdog device to ping |
| * |
| * The caller must hold wd_data->lock. |
| * |
| * If the watchdog has no own ping operation then it needs to be |
| * restarted via the start operation. This wrapper function does |
| * exactly that. |
| * We only ping when the watchdog device is running. |
| */ |
| |
| static int watchdog_ping(struct watchdog_device *wdd) |
| { |
| struct watchdog_core_data *wd_data = wdd->wd_data; |
| |
| if (!watchdog_active(wdd) && !watchdog_hw_running(wdd)) |
| return 0; |
| |
| set_bit(_WDOG_KEEPALIVE, &wd_data->status); |
| |
| wd_data->last_keepalive = ktime_get(); |
| return __watchdog_ping(wdd); |
| } |
| |
| static bool watchdog_worker_should_ping(struct watchdog_core_data *wd_data) |
| { |
| struct watchdog_device *wdd = wd_data->wdd; |
| |
| if (!wdd) |
| return false; |
| |
| if (watchdog_active(wdd)) |
| return true; |
| |
| return watchdog_hw_running(wdd) && !watchdog_past_open_deadline(wd_data); |
| } |
| |
| static void watchdog_ping_work(struct kthread_work *work) |
| { |
| struct watchdog_core_data *wd_data; |
| |
| wd_data = container_of(work, struct watchdog_core_data, work); |
| |
| mutex_lock(&wd_data->lock); |
| if (watchdog_worker_should_ping(wd_data)) |
| __watchdog_ping(wd_data->wdd); |
| mutex_unlock(&wd_data->lock); |
| } |
| |
| static enum hrtimer_restart watchdog_timer_expired(struct hrtimer *timer) |
| { |
| struct watchdog_core_data *wd_data; |
| |
| wd_data = container_of(timer, struct watchdog_core_data, timer); |
| |
| kthread_queue_work(watchdog_kworker, &wd_data->work); |
| return HRTIMER_NORESTART; |
| } |
| |
| /* |
| * watchdog_start: wrapper to start the watchdog. |
| * @wdd: the watchdog device to start |
| * |
| * The caller must hold wd_data->lock. |
| * |
| * Start the watchdog if it is not active and mark it active. |
| * This function returns zero on success or a negative errno code for |
| * failure. |
| */ |
| |
| static int watchdog_start(struct watchdog_device *wdd) |
| { |
| struct watchdog_core_data *wd_data = wdd->wd_data; |
| ktime_t started_at; |
| int err; |
| |
| if (watchdog_active(wdd)) |
| return 0; |
| |
| set_bit(_WDOG_KEEPALIVE, &wd_data->status); |
| |
| started_at = ktime_get(); |
| if (watchdog_hw_running(wdd) && wdd->ops->ping) { |
| err = __watchdog_ping(wdd); |
| if (err == 0) { |
| set_bit(WDOG_ACTIVE, &wdd->status); |
| watchdog_hrtimer_pretimeout_start(wdd); |
| } |
| } else { |
| err = wdd->ops->start(wdd); |
| if (err == 0) { |
| set_bit(WDOG_ACTIVE, &wdd->status); |
| wd_data->last_keepalive = started_at; |
| wd_data->last_hw_keepalive = started_at; |
| watchdog_update_worker(wdd); |
| watchdog_hrtimer_pretimeout_start(wdd); |
| } |
| } |
| |
| return err; |
| } |
| |
| /* |
| * watchdog_stop: wrapper to stop the watchdog. |
| * @wdd: the watchdog device to stop |
| * |
| * The caller must hold wd_data->lock. |
| * |
| * Stop the watchdog if it is still active and unmark it active. |
| * This function returns zero on success or a negative errno code for |
| * failure. |
| * If the 'nowayout' feature was set, the watchdog cannot be stopped. |
| */ |
| |
| static int watchdog_stop(struct watchdog_device *wdd) |
| { |
| int err = 0; |
| |
| if (!watchdog_active(wdd)) |
| return 0; |
| |
| if (test_bit(WDOG_NO_WAY_OUT, &wdd->status)) { |
| pr_info("watchdog%d: nowayout prevents watchdog being stopped!\n", |
| wdd->id); |
| return -EBUSY; |
| } |
| |
| if (wdd->ops->stop) { |
| clear_bit(WDOG_HW_RUNNING, &wdd->status); |
| err = wdd->ops->stop(wdd); |
| } else { |
| set_bit(WDOG_HW_RUNNING, &wdd->status); |
| } |
| |
| if (err == 0) { |
| clear_bit(WDOG_ACTIVE, &wdd->status); |
| watchdog_update_worker(wdd); |
| watchdog_hrtimer_pretimeout_stop(wdd); |
| } |
| |
| return err; |
| } |
| |
| /* |
| * watchdog_get_status: wrapper to get the watchdog status |
| * @wdd: the watchdog device to get the status from |
| * |
| * The caller must hold wd_data->lock. |
| * |
| * Get the watchdog's status flags. |
| */ |
| |
| static unsigned int watchdog_get_status(struct watchdog_device *wdd) |
| { |
| struct watchdog_core_data *wd_data = wdd->wd_data; |
| unsigned int status; |
| |
| if (wdd->ops->status) |
| status = wdd->ops->status(wdd); |
| else |
| status = wdd->bootstatus & (WDIOF_CARDRESET | |
| WDIOF_OVERHEAT | |
| WDIOF_FANFAULT | |
| WDIOF_EXTERN1 | |
| WDIOF_EXTERN2 | |
| WDIOF_POWERUNDER | |
| WDIOF_POWEROVER); |
| |
| if (test_bit(_WDOG_ALLOW_RELEASE, &wd_data->status)) |
| status |= WDIOF_MAGICCLOSE; |
| |
| if (test_and_clear_bit(_WDOG_KEEPALIVE, &wd_data->status)) |
| status |= WDIOF_KEEPALIVEPING; |
| |
| if (IS_ENABLED(CONFIG_WATCHDOG_HRTIMER_PRETIMEOUT)) |
| status |= WDIOF_PRETIMEOUT; |
| |
| return status; |
| } |
| |
| /* |
| * watchdog_set_timeout: set the watchdog timer timeout |
| * @wdd: the watchdog device to set the timeout for |
| * @timeout: timeout to set in seconds |
| * |
| * The caller must hold wd_data->lock. |
| */ |
| |
| static int watchdog_set_timeout(struct watchdog_device *wdd, |
| unsigned int timeout) |
| { |
| int err = 0; |
| |
| if (!(wdd->info->options & WDIOF_SETTIMEOUT)) |
| return -EOPNOTSUPP; |
| |
| if (watchdog_timeout_invalid(wdd, timeout)) |
| return -EINVAL; |
| |
| if (wdd->ops->set_timeout) { |
| err = wdd->ops->set_timeout(wdd, timeout); |
| } else { |
| wdd->timeout = timeout; |
| /* Disable pretimeout if it doesn't fit the new timeout */ |
| if (wdd->pretimeout >= wdd->timeout) |
| wdd->pretimeout = 0; |
| } |
| |
| watchdog_update_worker(wdd); |
| |
| return err; |
| } |
| |
| /* |
| * watchdog_set_pretimeout: set the watchdog timer pretimeout |
| * @wdd: the watchdog device to set the timeout for |
| * @timeout: pretimeout to set in seconds |
| */ |
| |
| static int watchdog_set_pretimeout(struct watchdog_device *wdd, |
| unsigned int timeout) |
| { |
| int err = 0; |
| |
| if (!watchdog_have_pretimeout(wdd)) |
| return -EOPNOTSUPP; |
| |
| if (watchdog_pretimeout_invalid(wdd, timeout)) |
| return -EINVAL; |
| |
| if (wdd->ops->set_pretimeout && (wdd->info->options & WDIOF_PRETIMEOUT)) |
| err = wdd->ops->set_pretimeout(wdd, timeout); |
| else |
| wdd->pretimeout = timeout; |
| |
| return err; |
| } |
| |
| /* |
| * watchdog_get_timeleft: wrapper to get the time left before a reboot |
| * @wdd: the watchdog device to get the remaining time from |
| * @timeleft: the time that's left |
| * |
| * The caller must hold wd_data->lock. |
| * |
| * Get the time before a watchdog will reboot (if not pinged). |
| */ |
| |
| static int watchdog_get_timeleft(struct watchdog_device *wdd, |
| unsigned int *timeleft) |
| { |
| *timeleft = 0; |
| |
| if (!wdd->ops->get_timeleft) |
| return -EOPNOTSUPP; |
| |
| *timeleft = wdd->ops->get_timeleft(wdd); |
| |
| return 0; |
| } |
| |
| #ifdef CONFIG_WATCHDOG_SYSFS |
| static ssize_t nowayout_show(struct device *dev, struct device_attribute *attr, |
| char *buf) |
| { |
| struct watchdog_device *wdd = dev_get_drvdata(dev); |
| |
| return sysfs_emit(buf, "%d\n", !!test_bit(WDOG_NO_WAY_OUT, |
| &wdd->status)); |
| } |
| |
| static ssize_t nowayout_store(struct device *dev, struct device_attribute *attr, |
| const char *buf, size_t len) |
| { |
| struct watchdog_device *wdd = dev_get_drvdata(dev); |
| unsigned int value; |
| int ret; |
| |
| ret = kstrtouint(buf, 0, &value); |
| if (ret) |
| return ret; |
| if (value > 1) |
| return -EINVAL; |
| /* nowayout cannot be disabled once set */ |
| if (test_bit(WDOG_NO_WAY_OUT, &wdd->status) && !value) |
| return -EPERM; |
| watchdog_set_nowayout(wdd, value); |
| return len; |
| } |
| static DEVICE_ATTR_RW(nowayout); |
| |
| static ssize_t status_show(struct device *dev, struct device_attribute *attr, |
| char *buf) |
| { |
| struct watchdog_device *wdd = dev_get_drvdata(dev); |
| struct watchdog_core_data *wd_data = wdd->wd_data; |
| unsigned int status; |
| |
| mutex_lock(&wd_data->lock); |
| status = watchdog_get_status(wdd); |
| mutex_unlock(&wd_data->lock); |
| |
| return sysfs_emit(buf, "0x%x\n", status); |
| } |
| static DEVICE_ATTR_RO(status); |
| |
| static ssize_t bootstatus_show(struct device *dev, |
| struct device_attribute *attr, char *buf) |
| { |
| struct watchdog_device *wdd = dev_get_drvdata(dev); |
| |
| return sysfs_emit(buf, "%u\n", wdd->bootstatus); |
| } |
| static DEVICE_ATTR_RO(bootstatus); |
| |
| static ssize_t timeleft_show(struct device *dev, struct device_attribute *attr, |
| char *buf) |
| { |
| struct watchdog_device *wdd = dev_get_drvdata(dev); |
| struct watchdog_core_data *wd_data = wdd->wd_data; |
| ssize_t status; |
| unsigned int val; |
| |
| mutex_lock(&wd_data->lock); |
| status = watchdog_get_timeleft(wdd, &val); |
| mutex_unlock(&wd_data->lock); |
| if (!status) |
| status = sysfs_emit(buf, "%u\n", val); |
| |
| return status; |
| } |
| static DEVICE_ATTR_RO(timeleft); |
| |
| static ssize_t timeout_show(struct device *dev, struct device_attribute *attr, |
| char *buf) |
| { |
| struct watchdog_device *wdd = dev_get_drvdata(dev); |
| |
| return sysfs_emit(buf, "%u\n", wdd->timeout); |
| } |
| static DEVICE_ATTR_RO(timeout); |
| |
| static ssize_t min_timeout_show(struct device *dev, |
| struct device_attribute *attr, char *buf) |
| { |
| struct watchdog_device *wdd = dev_get_drvdata(dev); |
| |
| return sysfs_emit(buf, "%u\n", wdd->min_timeout); |
| } |
| static DEVICE_ATTR_RO(min_timeout); |
| |
| static ssize_t max_timeout_show(struct device *dev, |
| struct device_attribute *attr, char *buf) |
| { |
| struct watchdog_device *wdd = dev_get_drvdata(dev); |
| |
| return sysfs_emit(buf, "%u\n", wdd->max_timeout); |
| } |
| static DEVICE_ATTR_RO(max_timeout); |
| |
| static ssize_t pretimeout_show(struct device *dev, |
| struct device_attribute *attr, char *buf) |
| { |
| struct watchdog_device *wdd = dev_get_drvdata(dev); |
| |
| return sysfs_emit(buf, "%u\n", wdd->pretimeout); |
| } |
| static DEVICE_ATTR_RO(pretimeout); |
| |
| static ssize_t identity_show(struct device *dev, struct device_attribute *attr, |
| char *buf) |
| { |
| struct watchdog_device *wdd = dev_get_drvdata(dev); |
| |
| return sysfs_emit(buf, "%s\n", wdd->info->identity); |
| } |
| static DEVICE_ATTR_RO(identity); |
| |
| static ssize_t state_show(struct device *dev, struct device_attribute *attr, |
| char *buf) |
| { |
| struct watchdog_device *wdd = dev_get_drvdata(dev); |
| |
| if (watchdog_active(wdd)) |
| return sysfs_emit(buf, "active\n"); |
| |
| return sysfs_emit(buf, "inactive\n"); |
| } |
| static DEVICE_ATTR_RO(state); |
| |
| static ssize_t pretimeout_available_governors_show(struct device *dev, |
| struct device_attribute *attr, char *buf) |
| { |
| return watchdog_pretimeout_available_governors_get(buf); |
| } |
| 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); |
| wd_data->cdev.owner = wdd->ops->owner; |
| |
| /* 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; |
| } |
| |
| /* 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) ")"); |