Commit | Line | Data |
---|---|---|
43316044 WVS |
1 | /* |
2 | * watchdog_dev.c | |
3 | * | |
4 | * (c) Copyright 2008-2011 Alan Cox <alan@lxorguk.ukuu.org.uk>, | |
5 | * All Rights Reserved. | |
6 | * | |
7 | * (c) Copyright 2008-2011 Wim Van Sebroeck <wim@iguana.be>. | |
8 | * | |
9 | * | |
10 | * This source code is part of the generic code that can be used | |
11 | * by all the watchdog timer drivers. | |
12 | * | |
13 | * This part of the generic code takes care of the following | |
14 | * misc device: /dev/watchdog. | |
15 | * | |
16 | * Based on source code of the following authors: | |
17 | * Matt Domsch <Matt_Domsch@dell.com>, | |
18 | * Rob Radez <rob@osinvestor.com>, | |
19 | * Rusty Lynch <rusty@linux.co.intel.com> | |
20 | * Satyam Sharma <satyam@infradead.org> | |
21 | * Randy Dunlap <randy.dunlap@oracle.com> | |
22 | * | |
23 | * This program is free software; you can redistribute it and/or | |
24 | * modify it under the terms of the GNU General Public License | |
25 | * as published by the Free Software Foundation; either version | |
26 | * 2 of the License, or (at your option) any later version. | |
27 | * | |
28 | * Neither Alan Cox, CymruNet Ltd., Wim Van Sebroeck nor Iguana vzw. | |
29 | * admit liability nor provide warranty for any of this software. | |
30 | * This material is provided "AS-IS" and at no charge. | |
31 | */ | |
32 | ||
33 | #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt | |
34 | ||
b4ffb190 | 35 | #include <linux/cdev.h> /* For character device */ |
43316044 | 36 | #include <linux/errno.h> /* For the -ENODEV/... values */ |
43316044 | 37 | #include <linux/fs.h> /* For file operations */ |
43316044 | 38 | #include <linux/init.h> /* For __init/__exit/... */ |
1ff68820 | 39 | #include <linux/hrtimer.h> /* For hrtimers */ |
b4ffb190 GR |
40 | #include <linux/kernel.h> /* For printk/panic/... */ |
41 | #include <linux/kref.h> /* For data references */ | |
1ff68820 | 42 | #include <linux/kthread.h> /* For kthread_work */ |
b4ffb190 GR |
43 | #include <linux/miscdevice.h> /* For handling misc devices */ |
44 | #include <linux/module.h> /* For module stuff/... */ | |
45 | #include <linux/mutex.h> /* For mutexes */ | |
44ea3942 | 46 | #include <linux/reboot.h> /* For reboot notifier */ |
b4ffb190 GR |
47 | #include <linux/slab.h> /* For memory functions */ |
48 | #include <linux/types.h> /* For standard types (like size_t) */ | |
49 | #include <linux/watchdog.h> /* For watchdog specific items */ | |
43316044 WVS |
50 | #include <linux/uaccess.h> /* For copy_to_user/put_user/... */ |
51 | ||
38a1222a CL |
52 | #include <uapi/linux/sched/types.h> /* For struct sched_param */ |
53 | ||
6cfb5aa8 | 54 | #include "watchdog_core.h" |
ff84136c | 55 | #include "watchdog_pretimeout.h" |
09a46e73 | 56 | |
b4ffb190 GR |
57 | /* |
58 | * struct watchdog_core_data - watchdog core internal data | |
59 | * @kref: Reference count. | |
60 | * @cdev: The watchdog's Character device. | |
61 | * @wdd: Pointer to watchdog device. | |
62 | * @lock: Lock for watchdog core. | |
63 | * @status: Watchdog core internal status bits. | |
64 | */ | |
65 | struct watchdog_core_data { | |
66 | struct kref kref; | |
67 | struct cdev cdev; | |
68 | struct watchdog_device *wdd; | |
69 | struct mutex lock; | |
1ff68820 CL |
70 | ktime_t last_keepalive; |
71 | ktime_t last_hw_keepalive; | |
72 | struct hrtimer timer; | |
73 | struct kthread_work work; | |
b4ffb190 GR |
74 | unsigned long status; /* Internal status bits */ |
75 | #define _WDOG_DEV_OPEN 0 /* Opened ? */ | |
76 | #define _WDOG_ALLOW_RELEASE 1 /* Did we receive the magic char ? */ | |
90b826f1 | 77 | #define _WDOG_KEEPALIVE 2 /* Did we receive a keepalive ? */ |
b4ffb190 GR |
78 | }; |
79 | ||
45f5fed3 AC |
80 | /* the dev_t structure to store the dynamically allocated watchdog devices */ |
81 | static dev_t watchdog_devt; | |
b4ffb190 GR |
82 | /* Reference to watchdog device behind /dev/watchdog */ |
83 | static struct watchdog_core_data *old_wd_data; | |
43316044 | 84 | |
38a1222a | 85 | static struct kthread_worker *watchdog_kworker; |
664a3923 | 86 | |
2501b015 SR |
87 | static bool handle_boot_enabled = |
88 | IS_ENABLED(CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED); | |
89 | ||
664a3923 GR |
90 | static inline bool watchdog_need_worker(struct watchdog_device *wdd) |
91 | { | |
92 | /* All variables in milli-seconds */ | |
93 | unsigned int hm = wdd->max_hw_heartbeat_ms; | |
94 | unsigned int t = wdd->timeout * 1000; | |
95 | ||
96 | /* | |
97 | * A worker to generate heartbeat requests is needed if all of the | |
98 | * following conditions are true. | |
99 | * - Userspace activated the watchdog. | |
100 | * - The driver provided a value for the maximum hardware timeout, and | |
101 | * thus is aware that the framework supports generating heartbeat | |
102 | * requests. | |
103 | * - Userspace requests a longer timeout than the hardware can handle. | |
3fbfe926 RV |
104 | * |
105 | * Alternatively, if userspace has not opened the watchdog | |
106 | * device, we take care of feeding the watchdog if it is | |
107 | * running. | |
664a3923 | 108 | */ |
3fbfe926 RV |
109 | return (hm && watchdog_active(wdd) && t > hm) || |
110 | (t && !watchdog_active(wdd) && watchdog_hw_running(wdd)); | |
664a3923 GR |
111 | } |
112 | ||
1ff68820 | 113 | static ktime_t watchdog_next_keepalive(struct watchdog_device *wdd) |
664a3923 GR |
114 | { |
115 | struct watchdog_core_data *wd_data = wdd->wd_data; | |
116 | unsigned int timeout_ms = wdd->timeout * 1000; | |
1ff68820 CL |
117 | ktime_t keepalive_interval; |
118 | ktime_t last_heartbeat, latest_heartbeat; | |
119 | ktime_t virt_timeout; | |
664a3923 GR |
120 | unsigned int hw_heartbeat_ms; |
121 | ||
1ff68820 CL |
122 | virt_timeout = ktime_add(wd_data->last_keepalive, |
123 | ms_to_ktime(timeout_ms)); | |
3fbfe926 | 124 | hw_heartbeat_ms = min_not_zero(timeout_ms, wdd->max_hw_heartbeat_ms); |
1ff68820 | 125 | keepalive_interval = ms_to_ktime(hw_heartbeat_ms / 2); |
664a3923 | 126 | |
ee142889 GR |
127 | if (!watchdog_active(wdd)) |
128 | return keepalive_interval; | |
129 | ||
664a3923 GR |
130 | /* |
131 | * To ensure that the watchdog times out wdd->timeout seconds | |
132 | * after the most recent ping from userspace, the last | |
133 | * worker ping has to come in hw_heartbeat_ms before this timeout. | |
134 | */ | |
1ff68820 CL |
135 | last_heartbeat = ktime_sub(virt_timeout, ms_to_ktime(hw_heartbeat_ms)); |
136 | latest_heartbeat = ktime_sub(last_heartbeat, ktime_get()); | |
137 | if (ktime_before(latest_heartbeat, keepalive_interval)) | |
138 | return latest_heartbeat; | |
139 | return keepalive_interval; | |
664a3923 GR |
140 | } |
141 | ||
142 | static inline void watchdog_update_worker(struct watchdog_device *wdd) | |
143 | { | |
144 | struct watchdog_core_data *wd_data = wdd->wd_data; | |
145 | ||
146 | if (watchdog_need_worker(wdd)) { | |
1ff68820 | 147 | ktime_t t = watchdog_next_keepalive(wdd); |
664a3923 GR |
148 | |
149 | if (t > 0) | |
1ff68820 | 150 | hrtimer_start(&wd_data->timer, t, HRTIMER_MODE_REL); |
664a3923 | 151 | } else { |
1ff68820 | 152 | hrtimer_cancel(&wd_data->timer); |
664a3923 GR |
153 | } |
154 | } | |
155 | ||
156 | static int __watchdog_ping(struct watchdog_device *wdd) | |
157 | { | |
15013ad8 | 158 | struct watchdog_core_data *wd_data = wdd->wd_data; |
1ff68820 | 159 | ktime_t earliest_keepalive, now; |
664a3923 GR |
160 | int err; |
161 | ||
1ff68820 CL |
162 | earliest_keepalive = ktime_add(wd_data->last_hw_keepalive, |
163 | ms_to_ktime(wdd->min_hw_heartbeat_ms)); | |
164 | now = ktime_get(); | |
165 | ||
166 | if (ktime_after(earliest_keepalive, now)) { | |
167 | hrtimer_start(&wd_data->timer, | |
168 | ktime_sub(earliest_keepalive, now), | |
169 | HRTIMER_MODE_REL); | |
15013ad8 GR |
170 | return 0; |
171 | } | |
172 | ||
1ff68820 | 173 | wd_data->last_hw_keepalive = now; |
15013ad8 | 174 | |
664a3923 GR |
175 | if (wdd->ops->ping) |
176 | err = wdd->ops->ping(wdd); /* ping the watchdog */ | |
177 | else | |
178 | err = wdd->ops->start(wdd); /* restart watchdog */ | |
179 | ||
180 | watchdog_update_worker(wdd); | |
181 | ||
182 | return err; | |
183 | } | |
184 | ||
43316044 WVS |
185 | /* |
186 | * watchdog_ping: ping the watchdog. | |
bc794ac3 | 187 | * @wdd: the watchdog device to ping |
43316044 | 188 | * |
b4ffb190 GR |
189 | * The caller must hold wd_data->lock. |
190 | * | |
43316044 WVS |
191 | * If the watchdog has no own ping operation then it needs to be |
192 | * restarted via the start operation. This wrapper function does | |
193 | * exactly that. | |
234445b4 | 194 | * We only ping when the watchdog device is running. |
43316044 WVS |
195 | */ |
196 | ||
bc794ac3 | 197 | static int watchdog_ping(struct watchdog_device *wdd) |
43316044 | 198 | { |
664a3923 | 199 | struct watchdog_core_data *wd_data = wdd->wd_data; |
e907df32 | 200 | |
ee142889 | 201 | if (!watchdog_active(wdd) && !watchdog_hw_running(wdd)) |
b4ffb190 | 202 | return 0; |
7a879824 | 203 | |
90b826f1 GR |
204 | set_bit(_WDOG_KEEPALIVE, &wd_data->status); |
205 | ||
1ff68820 | 206 | wd_data->last_keepalive = ktime_get(); |
664a3923 GR |
207 | return __watchdog_ping(wdd); |
208 | } | |
7a879824 | 209 | |
c013b65a RV |
210 | static bool watchdog_worker_should_ping(struct watchdog_core_data *wd_data) |
211 | { | |
212 | struct watchdog_device *wdd = wd_data->wdd; | |
213 | ||
214 | return wdd && (watchdog_active(wdd) || watchdog_hw_running(wdd)); | |
215 | } | |
216 | ||
38a1222a | 217 | static void watchdog_ping_work(struct kthread_work *work) |
664a3923 GR |
218 | { |
219 | struct watchdog_core_data *wd_data; | |
664a3923 | 220 | |
1ff68820 | 221 | wd_data = container_of(work, struct watchdog_core_data, work); |
664a3923 GR |
222 | |
223 | mutex_lock(&wd_data->lock); | |
c013b65a RV |
224 | if (watchdog_worker_should_ping(wd_data)) |
225 | __watchdog_ping(wd_data->wdd); | |
664a3923 | 226 | mutex_unlock(&wd_data->lock); |
234445b4 WVS |
227 | } |
228 | ||
1ff68820 CL |
229 | static enum hrtimer_restart watchdog_timer_expired(struct hrtimer *timer) |
230 | { | |
231 | struct watchdog_core_data *wd_data; | |
232 | ||
233 | wd_data = container_of(timer, struct watchdog_core_data, timer); | |
234 | ||
235 | kthread_queue_work(watchdog_kworker, &wd_data->work); | |
236 | return HRTIMER_NORESTART; | |
237 | } | |
238 | ||
234445b4 WVS |
239 | /* |
240 | * watchdog_start: wrapper to start the watchdog. | |
bc794ac3 | 241 | * @wdd: the watchdog device to start |
234445b4 | 242 | * |
b4ffb190 GR |
243 | * The caller must hold wd_data->lock. |
244 | * | |
234445b4 WVS |
245 | * Start the watchdog if it is not active and mark it active. |
246 | * This function returns zero on success or a negative errno code for | |
247 | * failure. | |
248 | */ | |
249 | ||
bc794ac3 | 250 | static int watchdog_start(struct watchdog_device *wdd) |
234445b4 | 251 | { |
664a3923 | 252 | struct watchdog_core_data *wd_data = wdd->wd_data; |
1ff68820 | 253 | ktime_t started_at; |
b4ffb190 | 254 | int err; |
e907df32 | 255 | |
bc794ac3 | 256 | if (watchdog_active(wdd)) |
b4ffb190 | 257 | return 0; |
234445b4 | 258 | |
90b826f1 GR |
259 | set_bit(_WDOG_KEEPALIVE, &wd_data->status); |
260 | ||
1ff68820 | 261 | started_at = ktime_get(); |
ee142889 GR |
262 | if (watchdog_hw_running(wdd) && wdd->ops->ping) |
263 | err = wdd->ops->ping(wdd); | |
264 | else | |
265 | err = wdd->ops->start(wdd); | |
664a3923 | 266 | if (err == 0) { |
bc794ac3 | 267 | set_bit(WDOG_ACTIVE, &wdd->status); |
664a3923 GR |
268 | wd_data->last_keepalive = started_at; |
269 | watchdog_update_worker(wdd); | |
270 | } | |
7a879824 | 271 | |
7a879824 | 272 | return err; |
234445b4 WVS |
273 | } |
274 | ||
275 | /* | |
276 | * watchdog_stop: wrapper to stop the watchdog. | |
bc794ac3 | 277 | * @wdd: the watchdog device to stop |
234445b4 | 278 | * |
b4ffb190 GR |
279 | * The caller must hold wd_data->lock. |
280 | * | |
234445b4 WVS |
281 | * Stop the watchdog if it is still active and unmark it active. |
282 | * This function returns zero on success or a negative errno code for | |
283 | * failure. | |
7e192b9c | 284 | * If the 'nowayout' feature was set, the watchdog cannot be stopped. |
234445b4 WVS |
285 | */ |
286 | ||
bc794ac3 | 287 | static int watchdog_stop(struct watchdog_device *wdd) |
234445b4 | 288 | { |
ee142889 | 289 | int err = 0; |
e907df32 | 290 | |
bc794ac3 | 291 | if (!watchdog_active(wdd)) |
b4ffb190 | 292 | return 0; |
7e192b9c | 293 | |
bc794ac3 | 294 | if (test_bit(WDOG_NO_WAY_OUT, &wdd->status)) { |
0254e953 GR |
295 | pr_info("watchdog%d: nowayout prevents watchdog being stopped!\n", |
296 | wdd->id); | |
b4ffb190 | 297 | return -EBUSY; |
7e192b9c | 298 | } |
234445b4 | 299 | |
3c10bbde GR |
300 | if (wdd->ops->stop) { |
301 | clear_bit(WDOG_HW_RUNNING, &wdd->status); | |
d0684c8a | 302 | err = wdd->ops->stop(wdd); |
3c10bbde | 303 | } else { |
d0684c8a | 304 | set_bit(WDOG_HW_RUNNING, &wdd->status); |
3c10bbde | 305 | } |
d0684c8a | 306 | |
664a3923 | 307 | if (err == 0) { |
bc794ac3 | 308 | clear_bit(WDOG_ACTIVE, &wdd->status); |
ee142889 | 309 | watchdog_update_worker(wdd); |
664a3923 | 310 | } |
7a879824 | 311 | |
7a879824 HG |
312 | return err; |
313 | } | |
314 | ||
315 | /* | |
316 | * watchdog_get_status: wrapper to get the watchdog status | |
bc794ac3 | 317 | * @wdd: the watchdog device to get the status from |
b4ffb190 GR |
318 | * |
319 | * The caller must hold wd_data->lock. | |
7a879824 HG |
320 | * |
321 | * Get the watchdog's status flags. | |
322 | */ | |
323 | ||
b4ffb190 | 324 | static unsigned int watchdog_get_status(struct watchdog_device *wdd) |
7a879824 | 325 | { |
90b826f1 GR |
326 | struct watchdog_core_data *wd_data = wdd->wd_data; |
327 | unsigned int status; | |
7a879824 | 328 | |
90b826f1 GR |
329 | if (wdd->ops->status) |
330 | status = wdd->ops->status(wdd); | |
331 | else | |
332 | status = wdd->bootstatus & (WDIOF_CARDRESET | | |
333 | WDIOF_OVERHEAT | | |
334 | WDIOF_FANFAULT | | |
335 | WDIOF_EXTERN1 | | |
336 | WDIOF_EXTERN2 | | |
337 | WDIOF_POWERUNDER | | |
338 | WDIOF_POWEROVER); | |
339 | ||
340 | if (test_bit(_WDOG_ALLOW_RELEASE, &wd_data->status)) | |
341 | status |= WDIOF_MAGICCLOSE; | |
342 | ||
343 | if (test_and_clear_bit(_WDOG_KEEPALIVE, &wd_data->status)) | |
344 | status |= WDIOF_KEEPALIVEPING; | |
345 | ||
346 | return status; | |
7a879824 HG |
347 | } |
348 | ||
349 | /* | |
350 | * watchdog_set_timeout: set the watchdog timer timeout | |
bc794ac3 | 351 | * @wdd: the watchdog device to set the timeout for |
7a879824 | 352 | * @timeout: timeout to set in seconds |
b4ffb190 GR |
353 | * |
354 | * The caller must hold wd_data->lock. | |
7a879824 HG |
355 | */ |
356 | ||
bc794ac3 | 357 | static int watchdog_set_timeout(struct watchdog_device *wdd, |
7a879824 HG |
358 | unsigned int timeout) |
359 | { | |
fb32e9b9 GR |
360 | int err = 0; |
361 | ||
362 | if (!(wdd->info->options & WDIOF_SETTIMEOUT)) | |
7a879824 HG |
363 | return -EOPNOTSUPP; |
364 | ||
bc794ac3 | 365 | if (watchdog_timeout_invalid(wdd, timeout)) |
7a879824 HG |
366 | return -EINVAL; |
367 | ||
df044e02 | 368 | if (wdd->ops->set_timeout) { |
fb32e9b9 | 369 | err = wdd->ops->set_timeout(wdd, timeout); |
df044e02 | 370 | } else { |
fb32e9b9 | 371 | wdd->timeout = timeout; |
df044e02 WS |
372 | /* Disable pretimeout if it doesn't fit the new timeout */ |
373 | if (wdd->pretimeout >= wdd->timeout) | |
374 | wdd->pretimeout = 0; | |
375 | } | |
fb32e9b9 | 376 | |
664a3923 GR |
377 | watchdog_update_worker(wdd); |
378 | ||
fb32e9b9 | 379 | return err; |
7a879824 HG |
380 | } |
381 | ||
df044e02 WS |
382 | /* |
383 | * watchdog_set_pretimeout: set the watchdog timer pretimeout | |
384 | * @wdd: the watchdog device to set the timeout for | |
385 | * @timeout: pretimeout to set in seconds | |
386 | */ | |
387 | ||
388 | static int watchdog_set_pretimeout(struct watchdog_device *wdd, | |
389 | unsigned int timeout) | |
390 | { | |
391 | int err = 0; | |
392 | ||
393 | if (!(wdd->info->options & WDIOF_PRETIMEOUT)) | |
394 | return -EOPNOTSUPP; | |
395 | ||
396 | if (watchdog_pretimeout_invalid(wdd, timeout)) | |
397 | return -EINVAL; | |
398 | ||
399 | if (wdd->ops->set_pretimeout) | |
400 | err = wdd->ops->set_pretimeout(wdd, timeout); | |
401 | else | |
402 | wdd->pretimeout = timeout; | |
403 | ||
404 | return err; | |
405 | } | |
406 | ||
7a879824 HG |
407 | /* |
408 | * watchdog_get_timeleft: wrapper to get the time left before a reboot | |
bc794ac3 | 409 | * @wdd: the watchdog device to get the remaining time from |
7a879824 HG |
410 | * @timeleft: the time that's left |
411 | * | |
b4ffb190 GR |
412 | * The caller must hold wd_data->lock. |
413 | * | |
7a879824 HG |
414 | * Get the time before a watchdog will reboot (if not pinged). |
415 | */ | |
416 | ||
bc794ac3 | 417 | static int watchdog_get_timeleft(struct watchdog_device *wdd, |
7a879824 HG |
418 | unsigned int *timeleft) |
419 | { | |
7a879824 | 420 | *timeleft = 0; |
b4ffb190 | 421 | |
bc794ac3 | 422 | if (!wdd->ops->get_timeleft) |
7a879824 HG |
423 | return -EOPNOTSUPP; |
424 | ||
bc794ac3 | 425 | *timeleft = wdd->ops->get_timeleft(wdd); |
7a879824 | 426 | |
b4ffb190 | 427 | return 0; |
7a879824 HG |
428 | } |
429 | ||
33b71126 PA |
430 | #ifdef CONFIG_WATCHDOG_SYSFS |
431 | static ssize_t nowayout_show(struct device *dev, struct device_attribute *attr, | |
432 | char *buf) | |
433 | { | |
434 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
435 | ||
436 | return sprintf(buf, "%d\n", !!test_bit(WDOG_NO_WAY_OUT, &wdd->status)); | |
437 | } | |
438 | static DEVICE_ATTR_RO(nowayout); | |
439 | ||
440 | static ssize_t status_show(struct device *dev, struct device_attribute *attr, | |
441 | char *buf) | |
442 | { | |
443 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
b4ffb190 GR |
444 | struct watchdog_core_data *wd_data = wdd->wd_data; |
445 | unsigned int status; | |
33b71126 | 446 | |
b4ffb190 GR |
447 | mutex_lock(&wd_data->lock); |
448 | status = watchdog_get_status(wdd); | |
449 | mutex_unlock(&wd_data->lock); | |
33b71126 | 450 | |
90b826f1 | 451 | return sprintf(buf, "0x%x\n", status); |
33b71126 PA |
452 | } |
453 | static DEVICE_ATTR_RO(status); | |
454 | ||
455 | static ssize_t bootstatus_show(struct device *dev, | |
456 | struct device_attribute *attr, char *buf) | |
457 | { | |
458 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
459 | ||
460 | return sprintf(buf, "%u\n", wdd->bootstatus); | |
461 | } | |
462 | static DEVICE_ATTR_RO(bootstatus); | |
463 | ||
464 | static ssize_t timeleft_show(struct device *dev, struct device_attribute *attr, | |
465 | char *buf) | |
466 | { | |
467 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
b4ffb190 | 468 | struct watchdog_core_data *wd_data = wdd->wd_data; |
33b71126 PA |
469 | ssize_t status; |
470 | unsigned int val; | |
471 | ||
b4ffb190 | 472 | mutex_lock(&wd_data->lock); |
33b71126 | 473 | status = watchdog_get_timeleft(wdd, &val); |
b4ffb190 | 474 | mutex_unlock(&wd_data->lock); |
33b71126 PA |
475 | if (!status) |
476 | status = sprintf(buf, "%u\n", val); | |
477 | ||
478 | return status; | |
479 | } | |
480 | static DEVICE_ATTR_RO(timeleft); | |
481 | ||
482 | static ssize_t timeout_show(struct device *dev, struct device_attribute *attr, | |
483 | char *buf) | |
484 | { | |
485 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
486 | ||
487 | return sprintf(buf, "%u\n", wdd->timeout); | |
488 | } | |
489 | static DEVICE_ATTR_RO(timeout); | |
490 | ||
df044e02 WS |
491 | static ssize_t pretimeout_show(struct device *dev, |
492 | struct device_attribute *attr, char *buf) | |
493 | { | |
494 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
495 | ||
496 | return sprintf(buf, "%u\n", wdd->pretimeout); | |
497 | } | |
498 | static DEVICE_ATTR_RO(pretimeout); | |
499 | ||
33b71126 PA |
500 | static ssize_t identity_show(struct device *dev, struct device_attribute *attr, |
501 | char *buf) | |
502 | { | |
503 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
504 | ||
505 | return sprintf(buf, "%s\n", wdd->info->identity); | |
506 | } | |
507 | static DEVICE_ATTR_RO(identity); | |
508 | ||
509 | static ssize_t state_show(struct device *dev, struct device_attribute *attr, | |
510 | char *buf) | |
511 | { | |
512 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
513 | ||
514 | if (watchdog_active(wdd)) | |
515 | return sprintf(buf, "active\n"); | |
516 | ||
517 | return sprintf(buf, "inactive\n"); | |
518 | } | |
519 | static DEVICE_ATTR_RO(state); | |
520 | ||
89873a71 VZ |
521 | static ssize_t pretimeout_available_governors_show(struct device *dev, |
522 | struct device_attribute *attr, char *buf) | |
523 | { | |
524 | return watchdog_pretimeout_available_governors_get(buf); | |
525 | } | |
526 | static DEVICE_ATTR_RO(pretimeout_available_governors); | |
527 | ||
ff84136c VZ |
528 | static ssize_t pretimeout_governor_show(struct device *dev, |
529 | struct device_attribute *attr, | |
530 | char *buf) | |
531 | { | |
532 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
533 | ||
534 | return watchdog_pretimeout_governor_get(wdd, buf); | |
535 | } | |
53f96cee VZ |
536 | |
537 | static ssize_t pretimeout_governor_store(struct device *dev, | |
538 | struct device_attribute *attr, | |
539 | const char *buf, size_t count) | |
540 | { | |
541 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
542 | int ret = watchdog_pretimeout_governor_set(wdd, buf); | |
543 | ||
544 | if (!ret) | |
545 | ret = count; | |
546 | ||
547 | return ret; | |
548 | } | |
549 | static DEVICE_ATTR_RW(pretimeout_governor); | |
ff84136c | 550 | |
33b71126 PA |
551 | static umode_t wdt_is_visible(struct kobject *kobj, struct attribute *attr, |
552 | int n) | |
553 | { | |
554 | struct device *dev = container_of(kobj, struct device, kobj); | |
555 | struct watchdog_device *wdd = dev_get_drvdata(dev); | |
556 | umode_t mode = attr->mode; | |
557 | ||
90b826f1 | 558 | if (attr == &dev_attr_timeleft.attr && !wdd->ops->get_timeleft) |
33b71126 | 559 | mode = 0; |
df044e02 WS |
560 | else if (attr == &dev_attr_pretimeout.attr && |
561 | !(wdd->info->options & WDIOF_PRETIMEOUT)) | |
562 | mode = 0; | |
89873a71 VZ |
563 | else if ((attr == &dev_attr_pretimeout_governor.attr || |
564 | attr == &dev_attr_pretimeout_available_governors.attr) && | |
ff84136c VZ |
565 | (!(wdd->info->options & WDIOF_PRETIMEOUT) || |
566 | !IS_ENABLED(CONFIG_WATCHDOG_PRETIMEOUT_GOV))) | |
567 | mode = 0; | |
33b71126 PA |
568 | |
569 | return mode; | |
570 | } | |
571 | static struct attribute *wdt_attrs[] = { | |
572 | &dev_attr_state.attr, | |
573 | &dev_attr_identity.attr, | |
574 | &dev_attr_timeout.attr, | |
df044e02 | 575 | &dev_attr_pretimeout.attr, |
33b71126 PA |
576 | &dev_attr_timeleft.attr, |
577 | &dev_attr_bootstatus.attr, | |
578 | &dev_attr_status.attr, | |
579 | &dev_attr_nowayout.attr, | |
ff84136c | 580 | &dev_attr_pretimeout_governor.attr, |
89873a71 | 581 | &dev_attr_pretimeout_available_governors.attr, |
33b71126 PA |
582 | NULL, |
583 | }; | |
584 | ||
585 | static const struct attribute_group wdt_group = { | |
586 | .attrs = wdt_attrs, | |
587 | .is_visible = wdt_is_visible, | |
588 | }; | |
589 | __ATTRIBUTE_GROUPS(wdt); | |
590 | #else | |
591 | #define wdt_groups NULL | |
592 | #endif | |
593 | ||
7a879824 HG |
594 | /* |
595 | * watchdog_ioctl_op: call the watchdog drivers ioctl op if defined | |
bc794ac3 | 596 | * @wdd: the watchdog device to do the ioctl on |
7a879824 HG |
597 | * @cmd: watchdog command |
598 | * @arg: argument pointer | |
b4ffb190 GR |
599 | * |
600 | * The caller must hold wd_data->lock. | |
7a879824 HG |
601 | */ |
602 | ||
bc794ac3 | 603 | static int watchdog_ioctl_op(struct watchdog_device *wdd, unsigned int cmd, |
7a879824 HG |
604 | unsigned long arg) |
605 | { | |
bc794ac3 | 606 | if (!wdd->ops->ioctl) |
7a879824 HG |
607 | return -ENOIOCTLCMD; |
608 | ||
b4ffb190 | 609 | return wdd->ops->ioctl(wdd, cmd, arg); |
43316044 WVS |
610 | } |
611 | ||
612 | /* | |
613 | * watchdog_write: writes to the watchdog. | |
614 | * @file: file from VFS | |
615 | * @data: user address of data | |
616 | * @len: length of data | |
617 | * @ppos: pointer to the file offset | |
618 | * | |
619 | * A write to a watchdog device is defined as a keepalive ping. | |
017cf080 | 620 | * Writing the magic 'V' sequence allows the next close to turn |
7e192b9c | 621 | * off the watchdog (if 'nowayout' is not set). |
43316044 WVS |
622 | */ |
623 | ||
624 | static ssize_t watchdog_write(struct file *file, const char __user *data, | |
625 | size_t len, loff_t *ppos) | |
626 | { | |
b4ffb190 GR |
627 | struct watchdog_core_data *wd_data = file->private_data; |
628 | struct watchdog_device *wdd; | |
629 | int err; | |
43316044 WVS |
630 | size_t i; |
631 | char c; | |
632 | ||
633 | if (len == 0) | |
634 | return 0; | |
635 | ||
017cf080 WVS |
636 | /* |
637 | * Note: just in case someone wrote the magic character | |
638 | * five months ago... | |
639 | */ | |
b4ffb190 | 640 | clear_bit(_WDOG_ALLOW_RELEASE, &wd_data->status); |
017cf080 WVS |
641 | |
642 | /* scan to see whether or not we got the magic character */ | |
43316044 WVS |
643 | for (i = 0; i != len; i++) { |
644 | if (get_user(c, data + i)) | |
645 | return -EFAULT; | |
017cf080 | 646 | if (c == 'V') |
b4ffb190 | 647 | set_bit(_WDOG_ALLOW_RELEASE, &wd_data->status); |
43316044 WVS |
648 | } |
649 | ||
650 | /* someone wrote to us, so we send the watchdog a keepalive ping */ | |
b4ffb190 GR |
651 | |
652 | err = -ENODEV; | |
653 | mutex_lock(&wd_data->lock); | |
654 | wdd = wd_data->wdd; | |
655 | if (wdd) | |
656 | err = watchdog_ping(wdd); | |
657 | mutex_unlock(&wd_data->lock); | |
658 | ||
5ef79663 AU |
659 | if (err < 0) |
660 | return err; | |
43316044 WVS |
661 | |
662 | return len; | |
663 | } | |
664 | ||
2fa03560 WVS |
665 | /* |
666 | * watchdog_ioctl: handle the different ioctl's for the watchdog device. | |
667 | * @file: file handle to the device | |
668 | * @cmd: watchdog command | |
669 | * @arg: argument pointer | |
670 | * | |
671 | * The watchdog API defines a common set of functions for all watchdogs | |
672 | * according to their available features. | |
673 | */ | |
674 | ||
675 | static long watchdog_ioctl(struct file *file, unsigned int cmd, | |
676 | unsigned long arg) | |
677 | { | |
b4ffb190 | 678 | struct watchdog_core_data *wd_data = file->private_data; |
2fa03560 | 679 | void __user *argp = (void __user *)arg; |
b4ffb190 | 680 | struct watchdog_device *wdd; |
2fa03560 WVS |
681 | int __user *p = argp; |
682 | unsigned int val; | |
234445b4 | 683 | int err; |
2fa03560 | 684 | |
b4ffb190 GR |
685 | mutex_lock(&wd_data->lock); |
686 | ||
687 | wdd = wd_data->wdd; | |
688 | if (!wdd) { | |
689 | err = -ENODEV; | |
690 | goto out_ioctl; | |
691 | } | |
692 | ||
7a879824 HG |
693 | err = watchdog_ioctl_op(wdd, cmd, arg); |
694 | if (err != -ENOIOCTLCMD) | |
b4ffb190 | 695 | goto out_ioctl; |
78d88fc0 | 696 | |
2fa03560 WVS |
697 | switch (cmd) { |
698 | case WDIOC_GETSUPPORT: | |
b4ffb190 | 699 | err = copy_to_user(argp, wdd->info, |
2fa03560 | 700 | sizeof(struct watchdog_info)) ? -EFAULT : 0; |
b4ffb190 | 701 | break; |
2fa03560 | 702 | case WDIOC_GETSTATUS: |
b4ffb190 GR |
703 | val = watchdog_get_status(wdd); |
704 | err = put_user(val, p); | |
705 | break; | |
2fa03560 | 706 | case WDIOC_GETBOOTSTATUS: |
b4ffb190 GR |
707 | err = put_user(wdd->bootstatus, p); |
708 | break; | |
234445b4 | 709 | case WDIOC_SETOPTIONS: |
b4ffb190 GR |
710 | if (get_user(val, p)) { |
711 | err = -EFAULT; | |
712 | break; | |
713 | } | |
234445b4 WVS |
714 | if (val & WDIOS_DISABLECARD) { |
715 | err = watchdog_stop(wdd); | |
716 | if (err < 0) | |
b4ffb190 | 717 | break; |
234445b4 | 718 | } |
b4ffb190 | 719 | if (val & WDIOS_ENABLECARD) |
234445b4 | 720 | err = watchdog_start(wdd); |
b4ffb190 | 721 | break; |
c2dc00e4 | 722 | case WDIOC_KEEPALIVE: |
b4ffb190 GR |
723 | if (!(wdd->info->options & WDIOF_KEEPALIVEPING)) { |
724 | err = -EOPNOTSUPP; | |
725 | break; | |
726 | } | |
727 | err = watchdog_ping(wdd); | |
728 | break; | |
014d694e | 729 | case WDIOC_SETTIMEOUT: |
b4ffb190 GR |
730 | if (get_user(val, p)) { |
731 | err = -EFAULT; | |
732 | break; | |
733 | } | |
7a879824 | 734 | err = watchdog_set_timeout(wdd, val); |
014d694e | 735 | if (err < 0) |
b4ffb190 | 736 | break; |
014d694e WVS |
737 | /* If the watchdog is active then we send a keepalive ping |
738 | * to make sure that the watchdog keep's running (and if | |
739 | * possible that it takes the new timeout) */ | |
5ef79663 AU |
740 | err = watchdog_ping(wdd); |
741 | if (err < 0) | |
b4ffb190 | 742 | break; |
e2af3092 | 743 | /* fall through */ |
014d694e WVS |
744 | case WDIOC_GETTIMEOUT: |
745 | /* timeout == 0 means that we don't know the timeout */ | |
b4ffb190 GR |
746 | if (wdd->timeout == 0) { |
747 | err = -EOPNOTSUPP; | |
748 | break; | |
749 | } | |
750 | err = put_user(wdd->timeout, p); | |
751 | break; | |
fd7b673c | 752 | case WDIOC_GETTIMELEFT: |
7a879824 | 753 | err = watchdog_get_timeleft(wdd, &val); |
b4ffb190 GR |
754 | if (err < 0) |
755 | break; | |
756 | err = put_user(val, p); | |
757 | break; | |
df044e02 WS |
758 | case WDIOC_SETPRETIMEOUT: |
759 | if (get_user(val, p)) { | |
760 | err = -EFAULT; | |
761 | break; | |
762 | } | |
763 | err = watchdog_set_pretimeout(wdd, val); | |
764 | break; | |
765 | case WDIOC_GETPRETIMEOUT: | |
766 | err = put_user(wdd->pretimeout, p); | |
767 | break; | |
2fa03560 | 768 | default: |
b4ffb190 GR |
769 | err = -ENOTTY; |
770 | break; | |
2fa03560 | 771 | } |
b4ffb190 GR |
772 | |
773 | out_ioctl: | |
774 | mutex_unlock(&wd_data->lock); | |
775 | return err; | |
2fa03560 WVS |
776 | } |
777 | ||
43316044 | 778 | /* |
45f5fed3 | 779 | * watchdog_open: open the /dev/watchdog* devices. |
43316044 WVS |
780 | * @inode: inode of device |
781 | * @file: file handle to device | |
782 | * | |
45f5fed3 | 783 | * When the /dev/watchdog* device gets opened, we start the watchdog. |
43316044 WVS |
784 | * Watch out: the /dev/watchdog device is single open, so we make sure |
785 | * it can only be opened once. | |
786 | */ | |
787 | ||
788 | static int watchdog_open(struct inode *inode, struct file *file) | |
789 | { | |
b4ffb190 | 790 | struct watchdog_core_data *wd_data; |
45f5fed3 | 791 | struct watchdog_device *wdd; |
4bcd615f | 792 | bool hw_running; |
b4ffb190 | 793 | int err; |
45f5fed3 AC |
794 | |
795 | /* Get the corresponding watchdog device */ | |
796 | if (imajor(inode) == MISC_MAJOR) | |
b4ffb190 | 797 | wd_data = old_wd_data; |
45f5fed3 | 798 | else |
b4ffb190 GR |
799 | wd_data = container_of(inode->i_cdev, struct watchdog_core_data, |
800 | cdev); | |
43316044 WVS |
801 | |
802 | /* the watchdog is single open! */ | |
b4ffb190 | 803 | if (test_and_set_bit(_WDOG_DEV_OPEN, &wd_data->status)) |
43316044 WVS |
804 | return -EBUSY; |
805 | ||
b4ffb190 GR |
806 | wdd = wd_data->wdd; |
807 | ||
43316044 WVS |
808 | /* |
809 | * If the /dev/watchdog device is open, we don't want the module | |
810 | * to be unloaded. | |
811 | */ | |
4bcd615f GR |
812 | hw_running = watchdog_hw_running(wdd); |
813 | if (!hw_running && !try_module_get(wdd->ops->owner)) { | |
b4ffb190 GR |
814 | err = -EBUSY; |
815 | goto out_clear; | |
816 | } | |
43316044 | 817 | |
234445b4 | 818 | err = watchdog_start(wdd); |
43316044 WVS |
819 | if (err < 0) |
820 | goto out_mod; | |
821 | ||
b4ffb190 | 822 | file->private_data = wd_data; |
45f5fed3 | 823 | |
4bcd615f | 824 | if (!hw_running) |
ee142889 | 825 | kref_get(&wd_data->kref); |
e907df32 | 826 | |
43316044 | 827 | /* dev/watchdog is a virtual (and thus non-seekable) filesystem */ |
c5bf68fe | 828 | return stream_open(inode, file); |
43316044 WVS |
829 | |
830 | out_mod: | |
b4ffb190 GR |
831 | module_put(wd_data->wdd->ops->owner); |
832 | out_clear: | |
833 | clear_bit(_WDOG_DEV_OPEN, &wd_data->status); | |
43316044 WVS |
834 | return err; |
835 | } | |
836 | ||
b4ffb190 GR |
837 | static void watchdog_core_data_release(struct kref *kref) |
838 | { | |
839 | struct watchdog_core_data *wd_data; | |
840 | ||
841 | wd_data = container_of(kref, struct watchdog_core_data, kref); | |
842 | ||
843 | kfree(wd_data); | |
844 | } | |
845 | ||
43316044 | 846 | /* |
45f5fed3 AC |
847 | * watchdog_release: release the watchdog device. |
848 | * @inode: inode of device | |
849 | * @file: file handle to device | |
43316044 | 850 | * |
017cf080 | 851 | * This is the code for when /dev/watchdog gets closed. We will only |
7e192b9c WVS |
852 | * stop the watchdog when we have received the magic char (and nowayout |
853 | * was not set), else the watchdog will keep running. | |
43316044 WVS |
854 | */ |
855 | ||
856 | static int watchdog_release(struct inode *inode, struct file *file) | |
857 | { | |
b4ffb190 GR |
858 | struct watchdog_core_data *wd_data = file->private_data; |
859 | struct watchdog_device *wdd; | |
017cf080 | 860 | int err = -EBUSY; |
d1ed3ba4 | 861 | bool running; |
017cf080 | 862 | |
b4ffb190 GR |
863 | mutex_lock(&wd_data->lock); |
864 | ||
865 | wdd = wd_data->wdd; | |
866 | if (!wdd) | |
867 | goto done; | |
868 | ||
017cf080 WVS |
869 | /* |
870 | * We only stop the watchdog if we received the magic character | |
7e192b9c WVS |
871 | * or if WDIOF_MAGICCLOSE is not set. If nowayout was set then |
872 | * watchdog_stop will fail. | |
017cf080 | 873 | */ |
fcf95670 HP |
874 | if (!test_bit(WDOG_ACTIVE, &wdd->status)) |
875 | err = 0; | |
b4ffb190 | 876 | else if (test_and_clear_bit(_WDOG_ALLOW_RELEASE, &wd_data->status) || |
fcf95670 | 877 | !(wdd->info->options & WDIOF_MAGICCLOSE)) |
017cf080 | 878 | err = watchdog_stop(wdd); |
43316044 | 879 | |
017cf080 | 880 | /* If the watchdog was not stopped, send a keepalive ping */ |
234445b4 | 881 | if (err < 0) { |
0254e953 | 882 | pr_crit("watchdog%d: watchdog did not stop!\n", wdd->id); |
43316044 WVS |
883 | watchdog_ping(wdd); |
884 | } | |
885 | ||
ee142889 | 886 | watchdog_update_worker(wdd); |
664a3923 | 887 | |
43316044 | 888 | /* make sure that /dev/watchdog can be re-opened */ |
b4ffb190 | 889 | clear_bit(_WDOG_DEV_OPEN, &wd_data->status); |
e907df32 | 890 | |
b4ffb190 | 891 | done: |
d1ed3ba4 | 892 | running = wdd && watchdog_hw_running(wdd); |
b4ffb190 | 893 | mutex_unlock(&wd_data->lock); |
ee142889 GR |
894 | /* |
895 | * Allow the owner module to be unloaded again unless the watchdog | |
896 | * is still running. If the watchdog is still running, it can not | |
897 | * be stopped, and its driver must not be unloaded. | |
898 | */ | |
d1ed3ba4 GR |
899 | if (!running) { |
900 | module_put(wd_data->cdev.owner); | |
ee142889 GR |
901 | kref_put(&wd_data->kref, watchdog_core_data_release); |
902 | } | |
43316044 WVS |
903 | return 0; |
904 | } | |
905 | ||
906 | static const struct file_operations watchdog_fops = { | |
907 | .owner = THIS_MODULE, | |
908 | .write = watchdog_write, | |
2fa03560 | 909 | .unlocked_ioctl = watchdog_ioctl, |
43316044 WVS |
910 | .open = watchdog_open, |
911 | .release = watchdog_release, | |
912 | }; | |
913 | ||
914 | static struct miscdevice watchdog_miscdev = { | |
915 | .minor = WATCHDOG_MINOR, | |
916 | .name = "watchdog", | |
917 | .fops = &watchdog_fops, | |
918 | }; | |
919 | ||
920 | /* | |
32ecc639 | 921 | * watchdog_cdev_register: register watchdog character device |
bc794ac3 | 922 | * @wdd: watchdog device |
32ecc639 | 923 | * @devno: character device number |
43316044 | 924 | * |
32ecc639 | 925 | * Register a watchdog character device including handling the legacy |
45f5fed3 AC |
926 | * /dev/watchdog node. /dev/watchdog is actually a miscdevice and |
927 | * thus we set it up like that. | |
43316044 WVS |
928 | */ |
929 | ||
32ecc639 | 930 | static int watchdog_cdev_register(struct watchdog_device *wdd, dev_t devno) |
43316044 | 931 | { |
b4ffb190 | 932 | struct watchdog_core_data *wd_data; |
32ecc639 | 933 | int err; |
45f5fed3 | 934 | |
b4ffb190 GR |
935 | wd_data = kzalloc(sizeof(struct watchdog_core_data), GFP_KERNEL); |
936 | if (!wd_data) | |
937 | return -ENOMEM; | |
938 | kref_init(&wd_data->kref); | |
939 | mutex_init(&wd_data->lock); | |
940 | ||
941 | wd_data->wdd = wdd; | |
942 | wdd->wd_data = wd_data; | |
943 | ||
38a1222a | 944 | if (IS_ERR_OR_NULL(watchdog_kworker)) |
664a3923 GR |
945 | return -ENODEV; |
946 | ||
1ff68820 CL |
947 | kthread_init_work(&wd_data->work, watchdog_ping_work); |
948 | hrtimer_init(&wd_data->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); | |
949 | wd_data->timer.function = watchdog_timer_expired; | |
664a3923 | 950 | |
bc794ac3 | 951 | if (wdd->id == 0) { |
b4ffb190 | 952 | old_wd_data = wd_data; |
bc794ac3 | 953 | watchdog_miscdev.parent = wdd->parent; |
45f5fed3 AC |
954 | err = misc_register(&watchdog_miscdev); |
955 | if (err != 0) { | |
956 | pr_err("%s: cannot register miscdev on minor=%d (err=%d).\n", | |
bc794ac3 | 957 | wdd->info->identity, WATCHDOG_MINOR, err); |
45f5fed3 AC |
958 | if (err == -EBUSY) |
959 | pr_err("%s: a legacy watchdog module is probably present.\n", | |
bc794ac3 | 960 | wdd->info->identity); |
b4ffb190 GR |
961 | old_wd_data = NULL; |
962 | kfree(wd_data); | |
45f5fed3 AC |
963 | return err; |
964 | } | |
43316044 WVS |
965 | } |
966 | ||
45f5fed3 | 967 | /* Fill in the data structures */ |
b4ffb190 GR |
968 | cdev_init(&wd_data->cdev, &watchdog_fops); |
969 | wd_data->cdev.owner = wdd->ops->owner; | |
45f5fed3 AC |
970 | |
971 | /* Add the device */ | |
b4ffb190 | 972 | err = cdev_add(&wd_data->cdev, devno, 1); |
45f5fed3 AC |
973 | if (err) { |
974 | pr_err("watchdog%d unable to add device %d:%d\n", | |
bc794ac3 GR |
975 | wdd->id, MAJOR(watchdog_devt), wdd->id); |
976 | if (wdd->id == 0) { | |
45f5fed3 | 977 | misc_deregister(&watchdog_miscdev); |
b4ffb190 GR |
978 | old_wd_data = NULL; |
979 | kref_put(&wd_data->kref, watchdog_core_data_release); | |
45f5fed3 | 980 | } |
ee142889 | 981 | return err; |
43316044 | 982 | } |
ee142889 | 983 | |
15013ad8 | 984 | /* Record time of most recent heartbeat as 'just before now'. */ |
1ff68820 | 985 | wd_data->last_hw_keepalive = ktime_sub(ktime_get(), 1); |
15013ad8 | 986 | |
ee142889 GR |
987 | /* |
988 | * If the watchdog is running, prevent its driver from being unloaded, | |
989 | * and schedule an immediate ping. | |
990 | */ | |
991 | if (watchdog_hw_running(wdd)) { | |
914d65f3 GR |
992 | __module_get(wdd->ops->owner); |
993 | kref_get(&wd_data->kref); | |
994 | if (handle_boot_enabled) | |
1ff68820 | 995 | hrtimer_start(&wd_data->timer, 0, HRTIMER_MODE_REL); |
914d65f3 | 996 | else |
2501b015 | 997 | pr_info("watchdog%d running and kernel based pre-userspace handler disabled\n", |
914d65f3 | 998 | wdd->id); |
ee142889 GR |
999 | } |
1000 | ||
1001 | return 0; | |
43316044 WVS |
1002 | } |
1003 | ||
1004 | /* | |
32ecc639 | 1005 | * watchdog_cdev_unregister: unregister watchdog character device |
43316044 WVS |
1006 | * @watchdog: watchdog device |
1007 | * | |
32ecc639 GR |
1008 | * Unregister watchdog character device and if needed the legacy |
1009 | * /dev/watchdog device. | |
43316044 WVS |
1010 | */ |
1011 | ||
32ecc639 | 1012 | static void watchdog_cdev_unregister(struct watchdog_device *wdd) |
43316044 | 1013 | { |
b4ffb190 | 1014 | struct watchdog_core_data *wd_data = wdd->wd_data; |
e907df32 | 1015 | |
b4ffb190 | 1016 | cdev_del(&wd_data->cdev); |
bc794ac3 | 1017 | if (wdd->id == 0) { |
45f5fed3 | 1018 | misc_deregister(&watchdog_miscdev); |
b4ffb190 | 1019 | old_wd_data = NULL; |
43316044 | 1020 | } |
b4ffb190 | 1021 | |
bb292ac1 GR |
1022 | if (watchdog_active(wdd) && |
1023 | test_bit(WDOG_STOP_ON_UNREGISTER, &wdd->status)) { | |
1024 | watchdog_stop(wdd); | |
1025 | } | |
1026 | ||
953b9dd7 WS |
1027 | mutex_lock(&wd_data->lock); |
1028 | wd_data->wdd = NULL; | |
1029 | wdd->wd_data = NULL; | |
1030 | mutex_unlock(&wd_data->lock); | |
1031 | ||
1ff68820 CL |
1032 | hrtimer_cancel(&wd_data->timer); |
1033 | kthread_cancel_work_sync(&wd_data->work); | |
664a3923 | 1034 | |
b4ffb190 | 1035 | kref_put(&wd_data->kref, watchdog_core_data_release); |
43316044 | 1036 | } |
45f5fed3 | 1037 | |
906d7a5c PA |
1038 | static struct class watchdog_class = { |
1039 | .name = "watchdog", | |
1040 | .owner = THIS_MODULE, | |
33b71126 | 1041 | .dev_groups = wdt_groups, |
906d7a5c PA |
1042 | }; |
1043 | ||
44ea3942 AS |
1044 | static int watchdog_reboot_notifier(struct notifier_block *nb, |
1045 | unsigned long code, void *data) | |
1046 | { | |
1047 | struct watchdog_device *wdd; | |
1048 | ||
1049 | wdd = container_of(nb, struct watchdog_device, reboot_nb); | |
1050 | if (code == SYS_DOWN || code == SYS_HALT) { | |
1051 | if (watchdog_active(wdd)) { | |
1052 | int ret; | |
1053 | ||
1054 | ret = wdd->ops->stop(wdd); | |
1055 | if (ret) | |
1056 | return NOTIFY_BAD; | |
1057 | } | |
1058 | } | |
1059 | ||
1060 | return NOTIFY_DONE; | |
1061 | } | |
1062 | ||
32ecc639 GR |
1063 | /* |
1064 | * watchdog_dev_register: register a watchdog device | |
1065 | * @wdd: watchdog device | |
1066 | * | |
1067 | * Register a watchdog device including handling the legacy | |
1068 | * /dev/watchdog node. /dev/watchdog is actually a miscdevice and | |
1069 | * thus we set it up like that. | |
1070 | */ | |
1071 | ||
1072 | int watchdog_dev_register(struct watchdog_device *wdd) | |
1073 | { | |
1074 | struct device *dev; | |
1075 | dev_t devno; | |
1076 | int ret; | |
1077 | ||
1078 | devno = MKDEV(MAJOR(watchdog_devt), wdd->id); | |
1079 | ||
1080 | ret = watchdog_cdev_register(wdd, devno); | |
1081 | if (ret) | |
1082 | return ret; | |
1083 | ||
faa58475 GR |
1084 | dev = device_create_with_groups(&watchdog_class, wdd->parent, |
1085 | devno, wdd, wdd->groups, | |
1086 | "watchdog%d", wdd->id); | |
32ecc639 GR |
1087 | if (IS_ERR(dev)) { |
1088 | watchdog_cdev_unregister(wdd); | |
1089 | return PTR_ERR(dev); | |
1090 | } | |
32ecc639 | 1091 | |
ff84136c VZ |
1092 | ret = watchdog_register_pretimeout(wdd); |
1093 | if (ret) { | |
1094 | device_destroy(&watchdog_class, devno); | |
1095 | watchdog_cdev_unregister(wdd); | |
44ea3942 AS |
1096 | return ret; |
1097 | } | |
1098 | ||
1099 | if (test_bit(WDOG_STOP_ON_REBOOT, &wdd->status)) { | |
1100 | wdd->reboot_nb.notifier_call = watchdog_reboot_notifier; | |
1101 | ||
1102 | ret = devm_register_reboot_notifier(dev, &wdd->reboot_nb); | |
1103 | if (ret) { | |
1104 | pr_err("watchdog%d: Cannot register reboot notifier (%d)\n", | |
1105 | wdd->id, ret); | |
1106 | watchdog_dev_unregister(wdd); | |
1107 | } | |
ff84136c VZ |
1108 | } |
1109 | ||
32ecc639 GR |
1110 | return ret; |
1111 | } | |
1112 | ||
1113 | /* | |
1114 | * watchdog_dev_unregister: unregister a watchdog device | |
1115 | * @watchdog: watchdog device | |
1116 | * | |
1117 | * Unregister watchdog device and if needed the legacy | |
1118 | * /dev/watchdog device. | |
1119 | */ | |
1120 | ||
1121 | void watchdog_dev_unregister(struct watchdog_device *wdd) | |
1122 | { | |
ff84136c | 1123 | watchdog_unregister_pretimeout(wdd); |
0254e953 | 1124 | device_destroy(&watchdog_class, wdd->wd_data->cdev.dev); |
b4ffb190 | 1125 | watchdog_cdev_unregister(wdd); |
32ecc639 GR |
1126 | } |
1127 | ||
45f5fed3 AC |
1128 | /* |
1129 | * watchdog_dev_init: init dev part of watchdog core | |
1130 | * | |
1131 | * Allocate a range of chardev nodes to use for watchdog devices | |
1132 | */ | |
1133 | ||
32ecc639 | 1134 | int __init watchdog_dev_init(void) |
45f5fed3 | 1135 | { |
906d7a5c | 1136 | int err; |
38a1222a | 1137 | struct sched_param param = {.sched_priority = MAX_RT_PRIO - 1,}; |
906d7a5c | 1138 | |
38a1222a CL |
1139 | watchdog_kworker = kthread_create_worker(0, "watchdogd"); |
1140 | if (IS_ERR(watchdog_kworker)) { | |
1141 | pr_err("Failed to create watchdog kworker\n"); | |
1142 | return PTR_ERR(watchdog_kworker); | |
664a3923 | 1143 | } |
38a1222a | 1144 | sched_setscheduler(watchdog_kworker->task, SCHED_FIFO, ¶m); |
664a3923 | 1145 | |
906d7a5c PA |
1146 | err = class_register(&watchdog_class); |
1147 | if (err < 0) { | |
1148 | pr_err("couldn't register class\n"); | |
138913cb | 1149 | goto err_register; |
906d7a5c PA |
1150 | } |
1151 | ||
1152 | err = alloc_chrdev_region(&watchdog_devt, 0, MAX_DOGS, "watchdog"); | |
1153 | if (err < 0) { | |
45f5fed3 | 1154 | pr_err("watchdog: unable to allocate char dev region\n"); |
138913cb | 1155 | goto err_alloc; |
906d7a5c PA |
1156 | } |
1157 | ||
32ecc639 | 1158 | return 0; |
138913cb WY |
1159 | |
1160 | err_alloc: | |
1161 | class_unregister(&watchdog_class); | |
1162 | err_register: | |
38a1222a | 1163 | kthread_destroy_worker(watchdog_kworker); |
138913cb | 1164 | return err; |
45f5fed3 AC |
1165 | } |
1166 | ||
1167 | /* | |
1168 | * watchdog_dev_exit: exit dev part of watchdog core | |
1169 | * | |
1170 | * Release the range of chardev nodes used for watchdog devices | |
1171 | */ | |
1172 | ||
1173 | void __exit watchdog_dev_exit(void) | |
1174 | { | |
1175 | unregister_chrdev_region(watchdog_devt, MAX_DOGS); | |
906d7a5c | 1176 | class_unregister(&watchdog_class); |
38a1222a | 1177 | kthread_destroy_worker(watchdog_kworker); |
45f5fed3 | 1178 | } |
2501b015 SR |
1179 | |
1180 | module_param(handle_boot_enabled, bool, 0444); | |
1181 | MODULE_PARM_DESC(handle_boot_enabled, | |
1182 | "Watchdog core auto-updates boot enabled watchdogs before userspace takes over (default=" | |
1183 | __MODULE_STRING(IS_ENABLED(CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED)) ")"); |