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29
30#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
31
32#include <linux/cdev.h>
33#include <linux/errno.h>
34#include <linux/fs.h>
35#include <linux/init.h>
36#include <linux/hrtimer.h>
37#include <linux/kernel.h>
38#include <linux/kthread.h>
39#include <linux/miscdevice.h>
40#include <linux/module.h>
41#include <linux/mutex.h>
42#include <linux/slab.h>
43#include <linux/types.h>
44#include <linux/watchdog.h>
45#include <linux/uaccess.h>
46
47#include "watchdog_core.h"
48#include "watchdog_pretimeout.h"
49
50
51static dev_t watchdog_devt;
52
53static struct watchdog_core_data *old_wd_data;
54
55static struct kthread_worker *watchdog_kworker;
56
57static bool handle_boot_enabled =
58 IS_ENABLED(CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED);
59
60static unsigned open_timeout = CONFIG_WATCHDOG_OPEN_TIMEOUT;
61
62static bool watchdog_past_open_deadline(struct watchdog_core_data *data)
63{
64 return ktime_after(ktime_get(), data->open_deadline);
65}
66
67static void watchdog_set_open_deadline(struct watchdog_core_data *data)
68{
69 data->open_deadline = open_timeout ?
70 ktime_get() + ktime_set(open_timeout, 0) : KTIME_MAX;
71}
72
73static inline bool watchdog_need_worker(struct watchdog_device *wdd)
74{
75
76 unsigned int hm = wdd->max_hw_heartbeat_ms;
77 unsigned int t = wdd->timeout * 1000;
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92 return (hm && watchdog_active(wdd) && t > hm) ||
93 (t && !watchdog_active(wdd) && watchdog_hw_running(wdd));
94}
95
96static ktime_t watchdog_next_keepalive(struct watchdog_device *wdd)
97{
98 struct watchdog_core_data *wd_data = wdd->wd_data;
99 unsigned int timeout_ms = wdd->timeout * 1000;
100 ktime_t keepalive_interval;
101 ktime_t last_heartbeat, latest_heartbeat;
102 ktime_t virt_timeout;
103 unsigned int hw_heartbeat_ms;
104
105 if (watchdog_active(wdd))
106 virt_timeout = ktime_add(wd_data->last_keepalive,
107 ms_to_ktime(timeout_ms));
108 else
109 virt_timeout = wd_data->open_deadline;
110
111 hw_heartbeat_ms = min_not_zero(timeout_ms, wdd->max_hw_heartbeat_ms);
112 keepalive_interval = ms_to_ktime(hw_heartbeat_ms / 2);
113
114
115
116
117
118
119 last_heartbeat = ktime_sub(virt_timeout, ms_to_ktime(hw_heartbeat_ms));
120 latest_heartbeat = ktime_sub(last_heartbeat, ktime_get());
121 if (ktime_before(latest_heartbeat, keepalive_interval))
122 return latest_heartbeat;
123 return keepalive_interval;
124}
125
126static inline void watchdog_update_worker(struct watchdog_device *wdd)
127{
128 struct watchdog_core_data *wd_data = wdd->wd_data;
129
130 if (watchdog_need_worker(wdd)) {
131 ktime_t t = watchdog_next_keepalive(wdd);
132
133 if (t > 0)
134 hrtimer_start(&wd_data->timer, t,
135 HRTIMER_MODE_REL_HARD);
136 } else {
137 hrtimer_cancel(&wd_data->timer);
138 }
139}
140
141static int __watchdog_ping(struct watchdog_device *wdd)
142{
143 struct watchdog_core_data *wd_data = wdd->wd_data;
144 ktime_t earliest_keepalive, now;
145 int err;
146
147 earliest_keepalive = ktime_add(wd_data->last_hw_keepalive,
148 ms_to_ktime(wdd->min_hw_heartbeat_ms));
149 now = ktime_get();
150
151 if (ktime_after(earliest_keepalive, now)) {
152 hrtimer_start(&wd_data->timer,
153 ktime_sub(earliest_keepalive, now),
154 HRTIMER_MODE_REL_HARD);
155 return 0;
156 }
157
158 wd_data->last_hw_keepalive = now;
159
160 if (wdd->ops->ping)
161 err = wdd->ops->ping(wdd);
162 else
163 err = wdd->ops->start(wdd);
164
165 if (err == 0)
166 watchdog_hrtimer_pretimeout_start(wdd);
167
168 watchdog_update_worker(wdd);
169
170 return err;
171}
172
173
174
175
176
177
178
179
180
181
182
183
184
185static int watchdog_ping(struct watchdog_device *wdd)
186{
187 struct watchdog_core_data *wd_data = wdd->wd_data;
188
189 if (!watchdog_active(wdd) && !watchdog_hw_running(wdd))
190 return 0;
191
192 set_bit(_WDOG_KEEPALIVE, &wd_data->status);
193
194 wd_data->last_keepalive = ktime_get();
195 return __watchdog_ping(wdd);
196}
197
198static bool watchdog_worker_should_ping(struct watchdog_core_data *wd_data)
199{
200 struct watchdog_device *wdd = wd_data->wdd;
201
202 if (!wdd)
203 return false;
204
205 if (watchdog_active(wdd))
206 return true;
207
208 return watchdog_hw_running(wdd) && !watchdog_past_open_deadline(wd_data);
209}
210
211static void watchdog_ping_work(struct kthread_work *work)
212{
213 struct watchdog_core_data *wd_data;
214
215 wd_data = container_of(work, struct watchdog_core_data, work);
216
217 mutex_lock(&wd_data->lock);
218 if (watchdog_worker_should_ping(wd_data))
219 __watchdog_ping(wd_data->wdd);
220 mutex_unlock(&wd_data->lock);
221}
222
223static enum hrtimer_restart watchdog_timer_expired(struct hrtimer *timer)
224{
225 struct watchdog_core_data *wd_data;
226
227 wd_data = container_of(timer, struct watchdog_core_data, timer);
228
229 kthread_queue_work(watchdog_kworker, &wd_data->work);
230 return HRTIMER_NORESTART;
231}
232
233
234
235
236
237
238
239
240
241
242
243
244static int watchdog_start(struct watchdog_device *wdd)
245{
246 struct watchdog_core_data *wd_data = wdd->wd_data;
247 ktime_t started_at;
248 int err;
249
250 if (watchdog_active(wdd))
251 return 0;
252
253 set_bit(_WDOG_KEEPALIVE, &wd_data->status);
254
255 started_at = ktime_get();
256 if (watchdog_hw_running(wdd) && wdd->ops->ping) {
257 err = __watchdog_ping(wdd);
258 if (err == 0) {
259 set_bit(WDOG_ACTIVE, &wdd->status);
260 watchdog_hrtimer_pretimeout_start(wdd);
261 }
262 } else {
263 err = wdd->ops->start(wdd);
264 if (err == 0) {
265 set_bit(WDOG_ACTIVE, &wdd->status);
266 wd_data->last_keepalive = started_at;
267 wd_data->last_hw_keepalive = started_at;
268 watchdog_update_worker(wdd);
269 watchdog_hrtimer_pretimeout_start(wdd);
270 }
271 }
272
273 return err;
274}
275
276
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279
280
281
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283
284
285
286
287
288static int watchdog_stop(struct watchdog_device *wdd)
289{
290 int err = 0;
291
292 if (!watchdog_active(wdd))
293 return 0;
294
295 if (test_bit(WDOG_NO_WAY_OUT, &wdd->status)) {
296 pr_info("watchdog%d: nowayout prevents watchdog being stopped!\n",
297 wdd->id);
298 return -EBUSY;
299 }
300
301 if (wdd->ops->stop) {
302 clear_bit(WDOG_HW_RUNNING, &wdd->status);
303 err = wdd->ops->stop(wdd);
304 } else {
305 set_bit(WDOG_HW_RUNNING, &wdd->status);
306 }
307
308 if (err == 0) {
309 clear_bit(WDOG_ACTIVE, &wdd->status);
310 watchdog_update_worker(wdd);
311 watchdog_hrtimer_pretimeout_stop(wdd);
312 }
313
314 return err;
315}
316
317
318
319
320
321
322
323
324
325
326static unsigned int watchdog_get_status(struct watchdog_device *wdd)
327{
328 struct watchdog_core_data *wd_data = wdd->wd_data;
329 unsigned int status;
330
331 if (wdd->ops->status)
332 status = wdd->ops->status(wdd);
333 else
334 status = wdd->bootstatus & (WDIOF_CARDRESET |
335 WDIOF_OVERHEAT |
336 WDIOF_FANFAULT |
337 WDIOF_EXTERN1 |
338 WDIOF_EXTERN2 |
339 WDIOF_POWERUNDER |
340 WDIOF_POWEROVER);
341
342 if (test_bit(_WDOG_ALLOW_RELEASE, &wd_data->status))
343 status |= WDIOF_MAGICCLOSE;
344
345 if (test_and_clear_bit(_WDOG_KEEPALIVE, &wd_data->status))
346 status |= WDIOF_KEEPALIVEPING;
347
348 if (IS_ENABLED(CONFIG_WATCHDOG_HRTIMER_PRETIMEOUT))
349 status |= WDIOF_PRETIMEOUT;
350
351 return status;
352}
353
354
355
356
357
358
359
360
361
362static int watchdog_set_timeout(struct watchdog_device *wdd,
363 unsigned int timeout)
364{
365 int err = 0;
366
367 if (!(wdd->info->options & WDIOF_SETTIMEOUT))
368 return -EOPNOTSUPP;
369
370 if (watchdog_timeout_invalid(wdd, timeout))
371 return -EINVAL;
372
373 if (wdd->ops->set_timeout) {
374 err = wdd->ops->set_timeout(wdd, timeout);
375 } else {
376 wdd->timeout = timeout;
377
378 if (wdd->pretimeout >= wdd->timeout)
379 wdd->pretimeout = 0;
380 }
381
382 watchdog_update_worker(wdd);
383
384 return err;
385}
386
387
388
389
390
391
392
393static int watchdog_set_pretimeout(struct watchdog_device *wdd,
394 unsigned int timeout)
395{
396 int err = 0;
397
398 if (!watchdog_have_pretimeout(wdd))
399 return -EOPNOTSUPP;
400
401 if (watchdog_pretimeout_invalid(wdd, timeout))
402 return -EINVAL;
403
404 if (wdd->ops->set_pretimeout && (wdd->info->options & WDIOF_PRETIMEOUT))
405 err = wdd->ops->set_pretimeout(wdd, timeout);
406 else
407 wdd->pretimeout = timeout;
408
409 return err;
410}
411
412
413
414
415
416
417
418
419
420
421
422static int watchdog_get_timeleft(struct watchdog_device *wdd,
423 unsigned int *timeleft)
424{
425 *timeleft = 0;
426
427 if (!wdd->ops->get_timeleft)
428 return -EOPNOTSUPP;
429
430 *timeleft = wdd->ops->get_timeleft(wdd);
431
432 return 0;
433}
434
435#ifdef CONFIG_WATCHDOG_SYSFS
436static ssize_t nowayout_show(struct device *dev, struct device_attribute *attr,
437 char *buf)
438{
439 struct watchdog_device *wdd = dev_get_drvdata(dev);
440
441 return sysfs_emit(buf, "%d\n", !!test_bit(WDOG_NO_WAY_OUT,
442 &wdd->status));
443}
444
445static ssize_t nowayout_store(struct device *dev, struct device_attribute *attr,
446 const char *buf, size_t len)
447{
448 struct watchdog_device *wdd = dev_get_drvdata(dev);
449 unsigned int value;
450 int ret;
451
452 ret = kstrtouint(buf, 0, &value);
453 if (ret)
454 return ret;
455 if (value > 1)
456 return -EINVAL;
457
458 if (test_bit(WDOG_NO_WAY_OUT, &wdd->status) && !value)
459 return -EPERM;
460 watchdog_set_nowayout(wdd, value);
461 return len;
462}
463static DEVICE_ATTR_RW(nowayout);
464
465static ssize_t status_show(struct device *dev, struct device_attribute *attr,
466 char *buf)
467{
468 struct watchdog_device *wdd = dev_get_drvdata(dev);
469 struct watchdog_core_data *wd_data = wdd->wd_data;
470 unsigned int status;
471
472 mutex_lock(&wd_data->lock);
473 status = watchdog_get_status(wdd);
474 mutex_unlock(&wd_data->lock);
475
476 return sysfs_emit(buf, "0x%x\n", status);
477}
478static DEVICE_ATTR_RO(status);
479
480static ssize_t bootstatus_show(struct device *dev,
481 struct device_attribute *attr, char *buf)
482{
483 struct watchdog_device *wdd = dev_get_drvdata(dev);
484
485 return sysfs_emit(buf, "%u\n", wdd->bootstatus);
486}
487static DEVICE_ATTR_RO(bootstatus);
488
489static ssize_t timeleft_show(struct device *dev, struct device_attribute *attr,
490 char *buf)
491{
492 struct watchdog_device *wdd = dev_get_drvdata(dev);
493 struct watchdog_core_data *wd_data = wdd->wd_data;
494 ssize_t status;
495 unsigned int val;
496
497 mutex_lock(&wd_data->lock);
498 status = watchdog_get_timeleft(wdd, &val);
499 mutex_unlock(&wd_data->lock);
500 if (!status)
501 status = sysfs_emit(buf, "%u\n", val);
502
503 return status;
504}
505static DEVICE_ATTR_RO(timeleft);
506
507static ssize_t timeout_show(struct device *dev, struct device_attribute *attr,
508 char *buf)
509{
510 struct watchdog_device *wdd = dev_get_drvdata(dev);
511
512 return sysfs_emit(buf, "%u\n", wdd->timeout);
513}
514static DEVICE_ATTR_RO(timeout);
515
516static ssize_t min_timeout_show(struct device *dev,
517 struct device_attribute *attr, char *buf)
518{
519 struct watchdog_device *wdd = dev_get_drvdata(dev);
520
521 return sysfs_emit(buf, "%u\n", wdd->min_timeout);
522}
523static DEVICE_ATTR_RO(min_timeout);
524
525static ssize_t max_timeout_show(struct device *dev,
526 struct device_attribute *attr, char *buf)
527{
528 struct watchdog_device *wdd = dev_get_drvdata(dev);
529
530 return sysfs_emit(buf, "%u\n", wdd->max_timeout);
531}
532static DEVICE_ATTR_RO(max_timeout);
533
534static ssize_t pretimeout_show(struct device *dev,
535 struct device_attribute *attr, char *buf)
536{
537 struct watchdog_device *wdd = dev_get_drvdata(dev);
538
539 return sysfs_emit(buf, "%u\n", wdd->pretimeout);
540}
541static DEVICE_ATTR_RO(pretimeout);
542
543static ssize_t identity_show(struct device *dev, struct device_attribute *attr,
544 char *buf)
545{
546 struct watchdog_device *wdd = dev_get_drvdata(dev);
547
548 return sysfs_emit(buf, "%s\n", wdd->info->identity);
549}
550static DEVICE_ATTR_RO(identity);
551
552static ssize_t state_show(struct device *dev, struct device_attribute *attr,
553 char *buf)
554{
555 struct watchdog_device *wdd = dev_get_drvdata(dev);
556
557 if (watchdog_active(wdd))
558 return sysfs_emit(buf, "active\n");
559
560 return sysfs_emit(buf, "inactive\n");
561}
562static DEVICE_ATTR_RO(state);
563
564static ssize_t pretimeout_available_governors_show(struct device *dev,
565 struct device_attribute *attr, char *buf)
566{
567 return watchdog_pretimeout_available_governors_get(buf);
568}
569static DEVICE_ATTR_RO(pretimeout_available_governors);
570
571static ssize_t pretimeout_governor_show(struct device *dev,
572 struct device_attribute *attr,
573 char *buf)
574{
575 struct watchdog_device *wdd = dev_get_drvdata(dev);
576
577 return watchdog_pretimeout_governor_get(wdd, buf);
578}
579
580static ssize_t pretimeout_governor_store(struct device *dev,
581 struct device_attribute *attr,
582 const char *buf, size_t count)
583{
584 struct watchdog_device *wdd = dev_get_drvdata(dev);
585 int ret = watchdog_pretimeout_governor_set(wdd, buf);
586
587 if (!ret)
588 ret = count;
589
590 return ret;
591}
592static DEVICE_ATTR_RW(pretimeout_governor);
593
594static umode_t wdt_is_visible(struct kobject *kobj, struct attribute *attr,
595 int n)
596{
597 struct device *dev = kobj_to_dev(kobj);
598 struct watchdog_device *wdd = dev_get_drvdata(dev);
599 umode_t mode = attr->mode;
600
601 if (attr == &dev_attr_timeleft.attr && !wdd->ops->get_timeleft)
602 mode = 0;
603 else if (attr == &dev_attr_pretimeout.attr && !watchdog_have_pretimeout(wdd))
604 mode = 0;
605 else if ((attr == &dev_attr_pretimeout_governor.attr ||
606 attr == &dev_attr_pretimeout_available_governors.attr) &&
607 (!watchdog_have_pretimeout(wdd) || !IS_ENABLED(CONFIG_WATCHDOG_PRETIMEOUT_GOV)))
608 mode = 0;
609
610 return mode;
611}
612static struct attribute *wdt_attrs[] = {
613 &dev_attr_state.attr,
614 &dev_attr_identity.attr,
615 &dev_attr_timeout.attr,
616 &dev_attr_min_timeout.attr,
617 &dev_attr_max_timeout.attr,
618 &dev_attr_pretimeout.attr,
619 &dev_attr_timeleft.attr,
620 &dev_attr_bootstatus.attr,
621 &dev_attr_status.attr,
622 &dev_attr_nowayout.attr,
623 &dev_attr_pretimeout_governor.attr,
624 &dev_attr_pretimeout_available_governors.attr,
625 NULL,
626};
627
628static const struct attribute_group wdt_group = {
629 .attrs = wdt_attrs,
630 .is_visible = wdt_is_visible,
631};
632__ATTRIBUTE_GROUPS(wdt);
633#else
634#define wdt_groups NULL
635#endif
636
637
638
639
640
641
642
643
644
645
646static int watchdog_ioctl_op(struct watchdog_device *wdd, unsigned int cmd,
647 unsigned long arg)
648{
649 if (!wdd->ops->ioctl)
650 return -ENOIOCTLCMD;
651
652 return wdd->ops->ioctl(wdd, cmd, arg);
653}
654
655
656
657
658
659
660
661
662
663
664
665
666
667static ssize_t watchdog_write(struct file *file, const char __user *data,
668 size_t len, loff_t *ppos)
669{
670 struct watchdog_core_data *wd_data = file->private_data;
671 struct watchdog_device *wdd;
672 int err;
673 size_t i;
674 char c;
675
676 if (len == 0)
677 return 0;
678
679
680
681
682
683 clear_bit(_WDOG_ALLOW_RELEASE, &wd_data->status);
684
685
686 for (i = 0; i != len; i++) {
687 if (get_user(c, data + i))
688 return -EFAULT;
689 if (c == 'V')
690 set_bit(_WDOG_ALLOW_RELEASE, &wd_data->status);
691 }
692
693
694
695 err = -ENODEV;
696 mutex_lock(&wd_data->lock);
697 wdd = wd_data->wdd;
698 if (wdd)
699 err = watchdog_ping(wdd);
700 mutex_unlock(&wd_data->lock);
701
702 if (err < 0)
703 return err;
704
705 return len;
706}
707
708
709
710
711
712
713
714
715
716
717
718static long watchdog_ioctl(struct file *file, unsigned int cmd,
719 unsigned long arg)
720{
721 struct watchdog_core_data *wd_data = file->private_data;
722 void __user *argp = (void __user *)arg;
723 struct watchdog_device *wdd;
724 int __user *p = argp;
725 unsigned int val;
726 int err;
727
728 mutex_lock(&wd_data->lock);
729
730 wdd = wd_data->wdd;
731 if (!wdd) {
732 err = -ENODEV;
733 goto out_ioctl;
734 }
735
736 err = watchdog_ioctl_op(wdd, cmd, arg);
737 if (err != -ENOIOCTLCMD)
738 goto out_ioctl;
739
740 switch (cmd) {
741 case WDIOC_GETSUPPORT:
742 err = copy_to_user(argp, wdd->info,
743 sizeof(struct watchdog_info)) ? -EFAULT : 0;
744 break;
745 case WDIOC_GETSTATUS:
746 val = watchdog_get_status(wdd);
747 err = put_user(val, p);
748 break;
749 case WDIOC_GETBOOTSTATUS:
750 err = put_user(wdd->bootstatus, p);
751 break;
752 case WDIOC_SETOPTIONS:
753 if (get_user(val, p)) {
754 err = -EFAULT;
755 break;
756 }
757 if (val & WDIOS_DISABLECARD) {
758 err = watchdog_stop(wdd);
759 if (err < 0)
760 break;
761 }
762 if (val & WDIOS_ENABLECARD)
763 err = watchdog_start(wdd);
764 break;
765 case WDIOC_KEEPALIVE:
766 if (!(wdd->info->options & WDIOF_KEEPALIVEPING)) {
767 err = -EOPNOTSUPP;
768 break;
769 }
770 err = watchdog_ping(wdd);
771 break;
772 case WDIOC_SETTIMEOUT:
773 if (get_user(val, p)) {
774 err = -EFAULT;
775 break;
776 }
777 err = watchdog_set_timeout(wdd, val);
778 if (err < 0)
779 break;
780
781
782
783 err = watchdog_ping(wdd);
784 if (err < 0)
785 break;
786 fallthrough;
787 case WDIOC_GETTIMEOUT:
788
789 if (wdd->timeout == 0) {
790 err = -EOPNOTSUPP;
791 break;
792 }
793 err = put_user(wdd->timeout, p);
794 break;
795 case WDIOC_GETTIMELEFT:
796 err = watchdog_get_timeleft(wdd, &val);
797 if (err < 0)
798 break;
799 err = put_user(val, p);
800 break;
801 case WDIOC_SETPRETIMEOUT:
802 if (get_user(val, p)) {
803 err = -EFAULT;
804 break;
805 }
806 err = watchdog_set_pretimeout(wdd, val);
807 break;
808 case WDIOC_GETPRETIMEOUT:
809 err = put_user(wdd->pretimeout, p);
810 break;
811 default:
812 err = -ENOTTY;
813 break;
814 }
815
816out_ioctl:
817 mutex_unlock(&wd_data->lock);
818 return err;
819}
820
821
822
823
824
825
826
827
828
829
830
831static int watchdog_open(struct inode *inode, struct file *file)
832{
833 struct watchdog_core_data *wd_data;
834 struct watchdog_device *wdd;
835 bool hw_running;
836 int err;
837
838
839 if (imajor(inode) == MISC_MAJOR)
840 wd_data = old_wd_data;
841 else
842 wd_data = container_of(inode->i_cdev, struct watchdog_core_data,
843 cdev);
844
845
846 if (test_and_set_bit(_WDOG_DEV_OPEN, &wd_data->status))
847 return -EBUSY;
848
849 wdd = wd_data->wdd;
850
851
852
853
854
855 hw_running = watchdog_hw_running(wdd);
856 if (!hw_running && !try_module_get(wdd->ops->owner)) {
857 err = -EBUSY;
858 goto out_clear;
859 }
860
861 err = watchdog_start(wdd);
862 if (err < 0)
863 goto out_mod;
864
865 file->private_data = wd_data;
866
867 if (!hw_running)
868 get_device(&wd_data->dev);
869
870
871
872
873
874
875
876
877 wd_data->open_deadline = KTIME_MAX;
878
879
880 return stream_open(inode, file);
881
882out_mod:
883 module_put(wd_data->wdd->ops->owner);
884out_clear:
885 clear_bit(_WDOG_DEV_OPEN, &wd_data->status);
886 return err;
887}
888
889static void watchdog_core_data_release(struct device *dev)
890{
891 struct watchdog_core_data *wd_data;
892
893 wd_data = container_of(dev, struct watchdog_core_data, dev);
894
895 kfree(wd_data);
896}
897
898
899
900
901
902
903
904
905
906
907
908static int watchdog_release(struct inode *inode, struct file *file)
909{
910 struct watchdog_core_data *wd_data = file->private_data;
911 struct watchdog_device *wdd;
912 int err = -EBUSY;
913 bool running;
914
915 mutex_lock(&wd_data->lock);
916
917 wdd = wd_data->wdd;
918 if (!wdd)
919 goto done;
920
921
922
923
924
925
926 if (!watchdog_active(wdd))
927 err = 0;
928 else if (test_and_clear_bit(_WDOG_ALLOW_RELEASE, &wd_data->status) ||
929 !(wdd->info->options & WDIOF_MAGICCLOSE))
930 err = watchdog_stop(wdd);
931
932
933 if (err < 0) {
934 pr_crit("watchdog%d: watchdog did not stop!\n", wdd->id);
935 watchdog_ping(wdd);
936 }
937
938 watchdog_update_worker(wdd);
939
940
941 clear_bit(_WDOG_DEV_OPEN, &wd_data->status);
942
943done:
944 running = wdd && watchdog_hw_running(wdd);
945 mutex_unlock(&wd_data->lock);
946
947
948
949
950
951 if (!running) {
952 module_put(wd_data->cdev.owner);
953 put_device(&wd_data->dev);
954 }
955 return 0;
956}
957
958static const struct file_operations watchdog_fops = {
959 .owner = THIS_MODULE,
960 .write = watchdog_write,
961 .unlocked_ioctl = watchdog_ioctl,
962 .compat_ioctl = compat_ptr_ioctl,
963 .open = watchdog_open,
964 .release = watchdog_release,
965};
966
967static struct miscdevice watchdog_miscdev = {
968 .minor = WATCHDOG_MINOR,
969 .name = "watchdog",
970 .fops = &watchdog_fops,
971};
972
973static struct class watchdog_class = {
974 .name = "watchdog",
975 .owner = THIS_MODULE,
976 .dev_groups = wdt_groups,
977};
978
979
980
981
982
983
984
985
986
987
988static int watchdog_cdev_register(struct watchdog_device *wdd)
989{
990 struct watchdog_core_data *wd_data;
991 int err;
992
993 wd_data = kzalloc(sizeof(struct watchdog_core_data), GFP_KERNEL);
994 if (!wd_data)
995 return -ENOMEM;
996 mutex_init(&wd_data->lock);
997
998 wd_data->wdd = wdd;
999 wdd->wd_data = wd_data;
1000
1001 if (IS_ERR_OR_NULL(watchdog_kworker)) {
1002 kfree(wd_data);
1003 return -ENODEV;
1004 }
1005
1006 device_initialize(&wd_data->dev);
1007 wd_data->dev.devt = MKDEV(MAJOR(watchdog_devt), wdd->id);
1008 wd_data->dev.class = &watchdog_class;
1009 wd_data->dev.parent = wdd->parent;
1010 wd_data->dev.groups = wdd->groups;
1011 wd_data->dev.release = watchdog_core_data_release;
1012 dev_set_drvdata(&wd_data->dev, wdd);
1013 dev_set_name(&wd_data->dev, "watchdog%d", wdd->id);
1014
1015 kthread_init_work(&wd_data->work, watchdog_ping_work);
1016 hrtimer_init(&wd_data->timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL_HARD);
1017 wd_data->timer.function = watchdog_timer_expired;
1018 watchdog_hrtimer_pretimeout_init(wdd);
1019
1020 if (wdd->id == 0) {
1021 old_wd_data = wd_data;
1022 watchdog_miscdev.parent = wdd->parent;
1023 err = misc_register(&watchdog_miscdev);
1024 if (err != 0) {
1025 pr_err("%s: cannot register miscdev on minor=%d (err=%d).\n",
1026 wdd->info->identity, WATCHDOG_MINOR, err);
1027 if (err == -EBUSY)
1028 pr_err("%s: a legacy watchdog module is probably present.\n",
1029 wdd->info->identity);
1030 old_wd_data = NULL;
1031 put_device(&wd_data->dev);
1032 return err;
1033 }
1034 }
1035
1036
1037 cdev_init(&wd_data->cdev, &watchdog_fops);
1038
1039
1040 err = cdev_device_add(&wd_data->cdev, &wd_data->dev);
1041 if (err) {
1042 pr_err("watchdog%d unable to add device %d:%d\n",
1043 wdd->id, MAJOR(watchdog_devt), wdd->id);
1044 if (wdd->id == 0) {
1045 misc_deregister(&watchdog_miscdev);
1046 old_wd_data = NULL;
1047 put_device(&wd_data->dev);
1048 }
1049 return err;
1050 }
1051
1052 wd_data->cdev.owner = wdd->ops->owner;
1053
1054
1055 wd_data->last_hw_keepalive = ktime_sub(ktime_get(), 1);
1056 watchdog_set_open_deadline(wd_data);
1057
1058
1059
1060
1061
1062 if (watchdog_hw_running(wdd)) {
1063 __module_get(wdd->ops->owner);
1064 get_device(&wd_data->dev);
1065 if (handle_boot_enabled)
1066 hrtimer_start(&wd_data->timer, 0,
1067 HRTIMER_MODE_REL_HARD);
1068 else
1069 pr_info("watchdog%d running and kernel based pre-userspace handler disabled\n",
1070 wdd->id);
1071 }
1072
1073 return 0;
1074}
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084static void watchdog_cdev_unregister(struct watchdog_device *wdd)
1085{
1086 struct watchdog_core_data *wd_data = wdd->wd_data;
1087
1088 cdev_device_del(&wd_data->cdev, &wd_data->dev);
1089 if (wdd->id == 0) {
1090 misc_deregister(&watchdog_miscdev);
1091 old_wd_data = NULL;
1092 }
1093
1094 if (watchdog_active(wdd) &&
1095 test_bit(WDOG_STOP_ON_UNREGISTER, &wdd->status)) {
1096 watchdog_stop(wdd);
1097 }
1098
1099 watchdog_hrtimer_pretimeout_stop(wdd);
1100
1101 mutex_lock(&wd_data->lock);
1102 wd_data->wdd = NULL;
1103 wdd->wd_data = NULL;
1104 mutex_unlock(&wd_data->lock);
1105
1106 hrtimer_cancel(&wd_data->timer);
1107 kthread_cancel_work_sync(&wd_data->work);
1108
1109 put_device(&wd_data->dev);
1110}
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121int watchdog_dev_register(struct watchdog_device *wdd)
1122{
1123 int ret;
1124
1125 ret = watchdog_cdev_register(wdd);
1126 if (ret)
1127 return ret;
1128
1129 ret = watchdog_register_pretimeout(wdd);
1130 if (ret)
1131 watchdog_cdev_unregister(wdd);
1132
1133 return ret;
1134}
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144void watchdog_dev_unregister(struct watchdog_device *wdd)
1145{
1146 watchdog_unregister_pretimeout(wdd);
1147 watchdog_cdev_unregister(wdd);
1148}
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161int watchdog_set_last_hw_keepalive(struct watchdog_device *wdd,
1162 unsigned int last_ping_ms)
1163{
1164 struct watchdog_core_data *wd_data;
1165 ktime_t now;
1166
1167 if (!wdd)
1168 return -EINVAL;
1169
1170 wd_data = wdd->wd_data;
1171
1172 now = ktime_get();
1173
1174 wd_data->last_hw_keepalive = ktime_sub(now, ms_to_ktime(last_ping_ms));
1175
1176 if (watchdog_hw_running(wdd) && handle_boot_enabled)
1177 return __watchdog_ping(wdd);
1178
1179 return 0;
1180}
1181EXPORT_SYMBOL_GPL(watchdog_set_last_hw_keepalive);
1182
1183
1184
1185
1186
1187
1188
1189int __init watchdog_dev_init(void)
1190{
1191 int err;
1192
1193 watchdog_kworker = kthread_create_worker(0, "watchdogd");
1194 if (IS_ERR(watchdog_kworker)) {
1195 pr_err("Failed to create watchdog kworker\n");
1196 return PTR_ERR(watchdog_kworker);
1197 }
1198 sched_set_fifo(watchdog_kworker->task);
1199
1200 err = class_register(&watchdog_class);
1201 if (err < 0) {
1202 pr_err("couldn't register class\n");
1203 goto err_register;
1204 }
1205
1206 err = alloc_chrdev_region(&watchdog_devt, 0, MAX_DOGS, "watchdog");
1207 if (err < 0) {
1208 pr_err("watchdog: unable to allocate char dev region\n");
1209 goto err_alloc;
1210 }
1211
1212 return 0;
1213
1214err_alloc:
1215 class_unregister(&watchdog_class);
1216err_register:
1217 kthread_destroy_worker(watchdog_kworker);
1218 return err;
1219}
1220
1221
1222
1223
1224
1225
1226
1227void __exit watchdog_dev_exit(void)
1228{
1229 unregister_chrdev_region(watchdog_devt, MAX_DOGS);
1230 class_unregister(&watchdog_class);
1231 kthread_destroy_worker(watchdog_kworker);
1232}
1233
1234int watchdog_dev_suspend(struct watchdog_device *wdd)
1235{
1236 struct watchdog_core_data *wd_data = wdd->wd_data;
1237 int ret = 0;
1238
1239 if (!wdd->wd_data)
1240 return -ENODEV;
1241
1242
1243 mutex_lock(&wd_data->lock);
1244 if (watchdog_worker_should_ping(wd_data))
1245 ret = __watchdog_ping(wd_data->wdd);
1246 mutex_unlock(&wd_data->lock);
1247
1248 if (ret)
1249 return ret;
1250
1251
1252
1253
1254
1255 hrtimer_cancel(&wd_data->timer);
1256 kthread_cancel_work_sync(&wd_data->work);
1257
1258 return 0;
1259}
1260
1261int watchdog_dev_resume(struct watchdog_device *wdd)
1262{
1263 struct watchdog_core_data *wd_data = wdd->wd_data;
1264 int ret = 0;
1265
1266 if (!wdd->wd_data)
1267 return -ENODEV;
1268
1269
1270
1271
1272
1273 mutex_lock(&wd_data->lock);
1274 if (watchdog_worker_should_ping(wd_data))
1275 ret = __watchdog_ping(wd_data->wdd);
1276 mutex_unlock(&wd_data->lock);
1277
1278 return ret;
1279}
1280
1281module_param(handle_boot_enabled, bool, 0444);
1282MODULE_PARM_DESC(handle_boot_enabled,
1283 "Watchdog core auto-updates boot enabled watchdogs before userspace takes over (default="
1284 __MODULE_STRING(IS_ENABLED(CONFIG_WATCHDOG_HANDLE_BOOT_ENABLED)) ")");
1285
1286module_param(open_timeout, uint, 0644);
1287MODULE_PARM_DESC(open_timeout,
1288 "Maximum time (in seconds, 0 means infinity) for userspace to take over a running watchdog (default="
1289 __MODULE_STRING(CONFIG_WATCHDOG_OPEN_TIMEOUT) ")");
1290