FreeBSD/Linux Kernel Cross Reference
sys/kern/kern_tc.c
1 /*-
2 * SPDX-License-Identifier: Beerware
3 *
4 * ----------------------------------------------------------------------------
5 * "THE BEER-WARE LICENSE" (Revision 42):
6 * <phk@FreeBSD.ORG> wrote this file. As long as you retain this notice you
7 * can do whatever you want with this stuff. If we meet some day, and you think
8 * this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp
9 * ----------------------------------------------------------------------------
10 *
11 * Copyright (c) 2011, 2015, 2016 The FreeBSD Foundation
12 * All rights reserved.
13 *
14 * Portions of this software were developed by Julien Ridoux at the University
15 * of Melbourne under sponsorship from the FreeBSD Foundation.
16 *
17 * Portions of this software were developed by Konstantin Belousov
18 * under sponsorship from the FreeBSD Foundation.
19 */
20
21 #include <sys/cdefs.h>
22 __FBSDID("$FreeBSD$");
23
24 #include "opt_ntp.h"
25 #include "opt_ffclock.h"
26
27 #include <sys/param.h>
28 #include <sys/kernel.h>
29 #include <sys/limits.h>
30 #include <sys/lock.h>
31 #include <sys/mutex.h>
32 #include <sys/proc.h>
33 #include <sys/sbuf.h>
34 #include <sys/sleepqueue.h>
35 #include <sys/sysctl.h>
36 #include <sys/syslog.h>
37 #include <sys/systm.h>
38 #include <sys/timeffc.h>
39 #include <sys/timepps.h>
40 #include <sys/timetc.h>
41 #include <sys/timex.h>
42 #include <sys/vdso.h>
43
44 /*
45 * A large step happens on boot. This constant detects such steps.
46 * It is relatively small so that ntp_update_second gets called enough
47 * in the typical 'missed a couple of seconds' case, but doesn't loop
48 * forever when the time step is large.
49 */
50 #define LARGE_STEP 200
51
52 /*
53 * Implement a dummy timecounter which we can use until we get a real one
54 * in the air. This allows the console and other early stuff to use
55 * time services.
56 */
57
58 static u_int
59 dummy_get_timecount(struct timecounter *tc)
60 {
61 static u_int now;
62
63 return (++now);
64 }
65
66 static struct timecounter dummy_timecounter = {
67 dummy_get_timecount, 0, ~0u, 1000000, "dummy", -1000000
68 };
69
70 struct timehands {
71 /* These fields must be initialized by the driver. */
72 struct timecounter *th_counter;
73 int64_t th_adjustment;
74 uint64_t th_scale;
75 u_int th_large_delta;
76 u_int th_offset_count;
77 struct bintime th_offset;
78 struct bintime th_bintime;
79 struct timeval th_microtime;
80 struct timespec th_nanotime;
81 struct bintime th_boottime;
82 /* Fields not to be copied in tc_windup start with th_generation. */
83 u_int th_generation;
84 struct timehands *th_next;
85 };
86
87 static struct timehands ths[16] = {
88 [0] = {
89 .th_counter = &dummy_timecounter,
90 .th_scale = (uint64_t)-1 / 1000000,
91 .th_large_delta = 1000000,
92 .th_offset = { .sec = 1 },
93 .th_generation = 1,
94 },
95 };
96
97 static struct timehands *volatile timehands = &ths[0];
98 struct timecounter *timecounter = &dummy_timecounter;
99 static struct timecounter *timecounters = &dummy_timecounter;
100
101 /* Mutex to protect the timecounter list. */
102 static struct mtx tc_lock;
103
104 int tc_min_ticktock_freq = 1;
105
106 volatile time_t time_second = 1;
107 volatile time_t time_uptime = 1;
108
109 static int sysctl_kern_boottime(SYSCTL_HANDLER_ARGS);
110 SYSCTL_PROC(_kern, KERN_BOOTTIME, boottime,
111 CTLTYPE_STRUCT | CTLFLAG_RD | CTLFLAG_MPSAFE, NULL, 0,
112 sysctl_kern_boottime, "S,timeval",
113 "System boottime");
114
115 SYSCTL_NODE(_kern, OID_AUTO, timecounter, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
116 "");
117 static SYSCTL_NODE(_kern_timecounter, OID_AUTO, tc,
118 CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
119 "");
120
121 static int timestepwarnings;
122 SYSCTL_INT(_kern_timecounter, OID_AUTO, stepwarnings, CTLFLAG_RWTUN,
123 ×tepwarnings, 0, "Log time steps");
124
125 static int timehands_count = 2;
126 SYSCTL_INT(_kern_timecounter, OID_AUTO, timehands_count,
127 CTLFLAG_RDTUN | CTLFLAG_NOFETCH,
128 &timehands_count, 0, "Count of timehands in rotation");
129
130 struct bintime bt_timethreshold;
131 struct bintime bt_tickthreshold;
132 sbintime_t sbt_timethreshold;
133 sbintime_t sbt_tickthreshold;
134 struct bintime tc_tick_bt;
135 sbintime_t tc_tick_sbt;
136 int tc_precexp;
137 int tc_timepercentage = TC_DEFAULTPERC;
138 static int sysctl_kern_timecounter_adjprecision(SYSCTL_HANDLER_ARGS);
139 SYSCTL_PROC(_kern_timecounter, OID_AUTO, alloweddeviation,
140 CTLTYPE_INT | CTLFLAG_RWTUN | CTLFLAG_MPSAFE, 0, 0,
141 sysctl_kern_timecounter_adjprecision, "I",
142 "Allowed time interval deviation in percents");
143
144 volatile int rtc_generation = 1;
145
146 static int tc_chosen; /* Non-zero if a specific tc was chosen via sysctl. */
147 static char tc_from_tunable[16];
148
149 static void tc_windup(struct bintime *new_boottimebin);
150 static void cpu_tick_calibrate(int);
151
152 void dtrace_getnanotime(struct timespec *tsp);
153 void dtrace_getnanouptime(struct timespec *tsp);
154
155 static int
156 sysctl_kern_boottime(SYSCTL_HANDLER_ARGS)
157 {
158 struct timeval boottime;
159
160 getboottime(&boottime);
161
162 /* i386 is the only arch which uses a 32bits time_t */
163 #ifdef __amd64__
164 #ifdef SCTL_MASK32
165 int tv[2];
166
167 if (req->flags & SCTL_MASK32) {
168 tv[0] = boottime.tv_sec;
169 tv[1] = boottime.tv_usec;
170 return (SYSCTL_OUT(req, tv, sizeof(tv)));
171 }
172 #endif
173 #endif
174 return (SYSCTL_OUT(req, &boottime, sizeof(boottime)));
175 }
176
177 static int
178 sysctl_kern_timecounter_get(SYSCTL_HANDLER_ARGS)
179 {
180 u_int ncount;
181 struct timecounter *tc = arg1;
182
183 ncount = tc->tc_get_timecount(tc);
184 return (sysctl_handle_int(oidp, &ncount, 0, req));
185 }
186
187 static int
188 sysctl_kern_timecounter_freq(SYSCTL_HANDLER_ARGS)
189 {
190 uint64_t freq;
191 struct timecounter *tc = arg1;
192
193 freq = tc->tc_frequency;
194 return (sysctl_handle_64(oidp, &freq, 0, req));
195 }
196
197 /*
198 * Return the difference between the timehands' counter value now and what
199 * was when we copied it to the timehands' offset_count.
200 */
201 static __inline u_int
202 tc_delta(struct timehands *th)
203 {
204 struct timecounter *tc;
205
206 tc = th->th_counter;
207 return ((tc->tc_get_timecount(tc) - th->th_offset_count) &
208 tc->tc_counter_mask);
209 }
210
211 /*
212 * Functions for reading the time. We have to loop until we are sure that
213 * the timehands that we operated on was not updated under our feet. See
214 * the comment in <sys/time.h> for a description of these 12 functions.
215 */
216
217 static __inline void
218 bintime_off(struct bintime *bt, u_int off)
219 {
220 struct timehands *th;
221 struct bintime *btp;
222 uint64_t scale, x;
223 u_int delta, gen, large_delta;
224
225 do {
226 th = timehands;
227 gen = atomic_load_acq_int(&th->th_generation);
228 btp = (struct bintime *)((vm_offset_t)th + off);
229 *bt = *btp;
230 scale = th->th_scale;
231 delta = tc_delta(th);
232 large_delta = th->th_large_delta;
233 atomic_thread_fence_acq();
234 } while (gen == 0 || gen != th->th_generation);
235
236 if (__predict_false(delta >= large_delta)) {
237 /* Avoid overflow for scale * delta. */
238 x = (scale >> 32) * delta;
239 bt->sec += x >> 32;
240 bintime_addx(bt, x << 32);
241 bintime_addx(bt, (scale & 0xffffffff) * delta);
242 } else {
243 bintime_addx(bt, scale * delta);
244 }
245 }
246 #define GETTHBINTIME(dst, member) \
247 do { \
248 _Static_assert(_Generic(((struct timehands *)NULL)->member, \
249 struct bintime: 1, default: 0) == 1, \
250 "struct timehands member is not of struct bintime type"); \
251 bintime_off(dst, __offsetof(struct timehands, member)); \
252 } while (0)
253
254 static __inline void
255 getthmember(void *out, size_t out_size, u_int off)
256 {
257 struct timehands *th;
258 u_int gen;
259
260 do {
261 th = timehands;
262 gen = atomic_load_acq_int(&th->th_generation);
263 memcpy(out, (char *)th + off, out_size);
264 atomic_thread_fence_acq();
265 } while (gen == 0 || gen != th->th_generation);
266 }
267 #define GETTHMEMBER(dst, member) \
268 do { \
269 _Static_assert(_Generic(*dst, \
270 __typeof(((struct timehands *)NULL)->member): 1, \
271 default: 0) == 1, \
272 "*dst and struct timehands member have different types"); \
273 getthmember(dst, sizeof(*dst), __offsetof(struct timehands, \
274 member)); \
275 } while (0)
276
277 #ifdef FFCLOCK
278 void
279 fbclock_binuptime(struct bintime *bt)
280 {
281
282 GETTHBINTIME(bt, th_offset);
283 }
284
285 void
286 fbclock_nanouptime(struct timespec *tsp)
287 {
288 struct bintime bt;
289
290 fbclock_binuptime(&bt);
291 bintime2timespec(&bt, tsp);
292 }
293
294 void
295 fbclock_microuptime(struct timeval *tvp)
296 {
297 struct bintime bt;
298
299 fbclock_binuptime(&bt);
300 bintime2timeval(&bt, tvp);
301 }
302
303 void
304 fbclock_bintime(struct bintime *bt)
305 {
306
307 GETTHBINTIME(bt, th_bintime);
308 }
309
310 void
311 fbclock_nanotime(struct timespec *tsp)
312 {
313 struct bintime bt;
314
315 fbclock_bintime(&bt);
316 bintime2timespec(&bt, tsp);
317 }
318
319 void
320 fbclock_microtime(struct timeval *tvp)
321 {
322 struct bintime bt;
323
324 fbclock_bintime(&bt);
325 bintime2timeval(&bt, tvp);
326 }
327
328 void
329 fbclock_getbinuptime(struct bintime *bt)
330 {
331
332 GETTHMEMBER(bt, th_offset);
333 }
334
335 void
336 fbclock_getnanouptime(struct timespec *tsp)
337 {
338 struct bintime bt;
339
340 GETTHMEMBER(&bt, th_offset);
341 bintime2timespec(&bt, tsp);
342 }
343
344 void
345 fbclock_getmicrouptime(struct timeval *tvp)
346 {
347 struct bintime bt;
348
349 GETTHMEMBER(&bt, th_offset);
350 bintime2timeval(&bt, tvp);
351 }
352
353 void
354 fbclock_getbintime(struct bintime *bt)
355 {
356
357 GETTHMEMBER(bt, th_bintime);
358 }
359
360 void
361 fbclock_getnanotime(struct timespec *tsp)
362 {
363
364 GETTHMEMBER(tsp, th_nanotime);
365 }
366
367 void
368 fbclock_getmicrotime(struct timeval *tvp)
369 {
370
371 GETTHMEMBER(tvp, th_microtime);
372 }
373 #else /* !FFCLOCK */
374
375 void
376 binuptime(struct bintime *bt)
377 {
378
379 GETTHBINTIME(bt, th_offset);
380 }
381
382 void
383 nanouptime(struct timespec *tsp)
384 {
385 struct bintime bt;
386
387 binuptime(&bt);
388 bintime2timespec(&bt, tsp);
389 }
390
391 void
392 microuptime(struct timeval *tvp)
393 {
394 struct bintime bt;
395
396 binuptime(&bt);
397 bintime2timeval(&bt, tvp);
398 }
399
400 void
401 bintime(struct bintime *bt)
402 {
403
404 GETTHBINTIME(bt, th_bintime);
405 }
406
407 void
408 nanotime(struct timespec *tsp)
409 {
410 struct bintime bt;
411
412 bintime(&bt);
413 bintime2timespec(&bt, tsp);
414 }
415
416 void
417 microtime(struct timeval *tvp)
418 {
419 struct bintime bt;
420
421 bintime(&bt);
422 bintime2timeval(&bt, tvp);
423 }
424
425 void
426 getbinuptime(struct bintime *bt)
427 {
428
429 GETTHMEMBER(bt, th_offset);
430 }
431
432 void
433 getnanouptime(struct timespec *tsp)
434 {
435 struct bintime bt;
436
437 GETTHMEMBER(&bt, th_offset);
438 bintime2timespec(&bt, tsp);
439 }
440
441 void
442 getmicrouptime(struct timeval *tvp)
443 {
444 struct bintime bt;
445
446 GETTHMEMBER(&bt, th_offset);
447 bintime2timeval(&bt, tvp);
448 }
449
450 void
451 getbintime(struct bintime *bt)
452 {
453
454 GETTHMEMBER(bt, th_bintime);
455 }
456
457 void
458 getnanotime(struct timespec *tsp)
459 {
460
461 GETTHMEMBER(tsp, th_nanotime);
462 }
463
464 void
465 getmicrotime(struct timeval *tvp)
466 {
467
468 GETTHMEMBER(tvp, th_microtime);
469 }
470 #endif /* FFCLOCK */
471
472 void
473 getboottime(struct timeval *boottime)
474 {
475 struct bintime boottimebin;
476
477 getboottimebin(&boottimebin);
478 bintime2timeval(&boottimebin, boottime);
479 }
480
481 void
482 getboottimebin(struct bintime *boottimebin)
483 {
484
485 GETTHMEMBER(boottimebin, th_boottime);
486 }
487
488 #ifdef FFCLOCK
489 /*
490 * Support for feed-forward synchronization algorithms. This is heavily inspired
491 * by the timehands mechanism but kept independent from it. *_windup() functions
492 * have some connection to avoid accessing the timecounter hardware more than
493 * necessary.
494 */
495
496 /* Feed-forward clock estimates kept updated by the synchronization daemon. */
497 struct ffclock_estimate ffclock_estimate;
498 struct bintime ffclock_boottime; /* Feed-forward boot time estimate. */
499 uint32_t ffclock_status; /* Feed-forward clock status. */
500 int8_t ffclock_updated; /* New estimates are available. */
501 struct mtx ffclock_mtx; /* Mutex on ffclock_estimate. */
502
503 struct fftimehands {
504 struct ffclock_estimate cest;
505 struct bintime tick_time;
506 struct bintime tick_time_lerp;
507 ffcounter tick_ffcount;
508 uint64_t period_lerp;
509 volatile uint8_t gen;
510 struct fftimehands *next;
511 };
512
513 #define NUM_ELEMENTS(x) (sizeof(x) / sizeof(*x))
514
515 static struct fftimehands ffth[10];
516 static struct fftimehands *volatile fftimehands = ffth;
517
518 static void
519 ffclock_init(void)
520 {
521 struct fftimehands *cur;
522 struct fftimehands *last;
523
524 memset(ffth, 0, sizeof(ffth));
525
526 last = ffth + NUM_ELEMENTS(ffth) - 1;
527 for (cur = ffth; cur < last; cur++)
528 cur->next = cur + 1;
529 last->next = ffth;
530
531 ffclock_updated = 0;
532 ffclock_status = FFCLOCK_STA_UNSYNC;
533 mtx_init(&ffclock_mtx, "ffclock lock", NULL, MTX_DEF);
534 }
535
536 /*
537 * Reset the feed-forward clock estimates. Called from inittodr() to get things
538 * kick started and uses the timecounter nominal frequency as a first period
539 * estimate. Note: this function may be called several time just after boot.
540 * Note: this is the only function that sets the value of boot time for the
541 * monotonic (i.e. uptime) version of the feed-forward clock.
542 */
543 void
544 ffclock_reset_clock(struct timespec *ts)
545 {
546 struct timecounter *tc;
547 struct ffclock_estimate cest;
548
549 tc = timehands->th_counter;
550 memset(&cest, 0, sizeof(struct ffclock_estimate));
551
552 timespec2bintime(ts, &ffclock_boottime);
553 timespec2bintime(ts, &(cest.update_time));
554 ffclock_read_counter(&cest.update_ffcount);
555 cest.leapsec_next = 0;
556 cest.period = ((1ULL << 63) / tc->tc_frequency) << 1;
557 cest.errb_abs = 0;
558 cest.errb_rate = 0;
559 cest.status = FFCLOCK_STA_UNSYNC;
560 cest.leapsec_total = 0;
561 cest.leapsec = 0;
562
563 mtx_lock(&ffclock_mtx);
564 bcopy(&cest, &ffclock_estimate, sizeof(struct ffclock_estimate));
565 ffclock_updated = INT8_MAX;
566 mtx_unlock(&ffclock_mtx);
567
568 printf("ffclock reset: %s (%llu Hz), time = %ld.%09lu\n", tc->tc_name,
569 (unsigned long long)tc->tc_frequency, (long)ts->tv_sec,
570 (unsigned long)ts->tv_nsec);
571 }
572
573 /*
574 * Sub-routine to convert a time interval measured in RAW counter units to time
575 * in seconds stored in bintime format.
576 * NOTE: bintime_mul requires u_int, but the value of the ffcounter may be
577 * larger than the max value of u_int (on 32 bit architecture). Loop to consume
578 * extra cycles.
579 */
580 static void
581 ffclock_convert_delta(ffcounter ffdelta, uint64_t period, struct bintime *bt)
582 {
583 struct bintime bt2;
584 ffcounter delta, delta_max;
585
586 delta_max = (1ULL << (8 * sizeof(unsigned int))) - 1;
587 bintime_clear(bt);
588 do {
589 if (ffdelta > delta_max)
590 delta = delta_max;
591 else
592 delta = ffdelta;
593 bt2.sec = 0;
594 bt2.frac = period;
595 bintime_mul(&bt2, (unsigned int)delta);
596 bintime_add(bt, &bt2);
597 ffdelta -= delta;
598 } while (ffdelta > 0);
599 }
600
601 /*
602 * Update the fftimehands.
603 * Push the tick ffcount and time(s) forward based on current clock estimate.
604 * The conversion from ffcounter to bintime relies on the difference clock
605 * principle, whose accuracy relies on computing small time intervals. If a new
606 * clock estimate has been passed by the synchronisation daemon, make it
607 * current, and compute the linear interpolation for monotonic time if needed.
608 */
609 static void
610 ffclock_windup(unsigned int delta)
611 {
612 struct ffclock_estimate *cest;
613 struct fftimehands *ffth;
614 struct bintime bt, gap_lerp;
615 ffcounter ffdelta;
616 uint64_t frac;
617 unsigned int polling;
618 uint8_t forward_jump, ogen;
619
620 /*
621 * Pick the next timehand, copy current ffclock estimates and move tick
622 * times and counter forward.
623 */
624 forward_jump = 0;
625 ffth = fftimehands->next;
626 ogen = ffth->gen;
627 ffth->gen = 0;
628 cest = &ffth->cest;
629 bcopy(&fftimehands->cest, cest, sizeof(struct ffclock_estimate));
630 ffdelta = (ffcounter)delta;
631 ffth->period_lerp = fftimehands->period_lerp;
632
633 ffth->tick_time = fftimehands->tick_time;
634 ffclock_convert_delta(ffdelta, cest->period, &bt);
635 bintime_add(&ffth->tick_time, &bt);
636
637 ffth->tick_time_lerp = fftimehands->tick_time_lerp;
638 ffclock_convert_delta(ffdelta, ffth->period_lerp, &bt);
639 bintime_add(&ffth->tick_time_lerp, &bt);
640
641 ffth->tick_ffcount = fftimehands->tick_ffcount + ffdelta;
642
643 /*
644 * Assess the status of the clock, if the last update is too old, it is
645 * likely the synchronisation daemon is dead and the clock is free
646 * running.
647 */
648 if (ffclock_updated == 0) {
649 ffdelta = ffth->tick_ffcount - cest->update_ffcount;
650 ffclock_convert_delta(ffdelta, cest->period, &bt);
651 if (bt.sec > 2 * FFCLOCK_SKM_SCALE)
652 ffclock_status |= FFCLOCK_STA_UNSYNC;
653 }
654
655 /*
656 * If available, grab updated clock estimates and make them current.
657 * Recompute time at this tick using the updated estimates. The clock
658 * estimates passed the feed-forward synchronisation daemon may result
659 * in time conversion that is not monotonically increasing (just after
660 * the update). time_lerp is a particular linear interpolation over the
661 * synchronisation algo polling period that ensures monotonicity for the
662 * clock ids requesting it.
663 */
664 if (ffclock_updated > 0) {
665 bcopy(&ffclock_estimate, cest, sizeof(struct ffclock_estimate));
666 ffdelta = ffth->tick_ffcount - cest->update_ffcount;
667 ffth->tick_time = cest->update_time;
668 ffclock_convert_delta(ffdelta, cest->period, &bt);
669 bintime_add(&ffth->tick_time, &bt);
670
671 /* ffclock_reset sets ffclock_updated to INT8_MAX */
672 if (ffclock_updated == INT8_MAX)
673 ffth->tick_time_lerp = ffth->tick_time;
674
675 if (bintime_cmp(&ffth->tick_time, &ffth->tick_time_lerp, >))
676 forward_jump = 1;
677 else
678 forward_jump = 0;
679
680 bintime_clear(&gap_lerp);
681 if (forward_jump) {
682 gap_lerp = ffth->tick_time;
683 bintime_sub(&gap_lerp, &ffth->tick_time_lerp);
684 } else {
685 gap_lerp = ffth->tick_time_lerp;
686 bintime_sub(&gap_lerp, &ffth->tick_time);
687 }
688
689 /*
690 * The reset from the RTC clock may be far from accurate, and
691 * reducing the gap between real time and interpolated time
692 * could take a very long time if the interpolated clock insists
693 * on strict monotonicity. The clock is reset under very strict
694 * conditions (kernel time is known to be wrong and
695 * synchronization daemon has been restarted recently.
696 * ffclock_boottime absorbs the jump to ensure boot time is
697 * correct and uptime functions stay consistent.
698 */
699 if (((ffclock_status & FFCLOCK_STA_UNSYNC) == FFCLOCK_STA_UNSYNC) &&
700 ((cest->status & FFCLOCK_STA_UNSYNC) == 0) &&
701 ((cest->status & FFCLOCK_STA_WARMUP) == FFCLOCK_STA_WARMUP)) {
702 if (forward_jump)
703 bintime_add(&ffclock_boottime, &gap_lerp);
704 else
705 bintime_sub(&ffclock_boottime, &gap_lerp);
706 ffth->tick_time_lerp = ffth->tick_time;
707 bintime_clear(&gap_lerp);
708 }
709
710 ffclock_status = cest->status;
711 ffth->period_lerp = cest->period;
712
713 /*
714 * Compute corrected period used for the linear interpolation of
715 * time. The rate of linear interpolation is capped to 5000PPM
716 * (5ms/s).
717 */
718 if (bintime_isset(&gap_lerp)) {
719 ffdelta = cest->update_ffcount;
720 ffdelta -= fftimehands->cest.update_ffcount;
721 ffclock_convert_delta(ffdelta, cest->period, &bt);
722 polling = bt.sec;
723 bt.sec = 0;
724 bt.frac = 5000000 * (uint64_t)18446744073LL;
725 bintime_mul(&bt, polling);
726 if (bintime_cmp(&gap_lerp, &bt, >))
727 gap_lerp = bt;
728
729 /* Approximate 1 sec by 1-(1/2^64) to ease arithmetic */
730 frac = 0;
731 if (gap_lerp.sec > 0) {
732 frac -= 1;
733 frac /= ffdelta / gap_lerp.sec;
734 }
735 frac += gap_lerp.frac / ffdelta;
736
737 if (forward_jump)
738 ffth->period_lerp += frac;
739 else
740 ffth->period_lerp -= frac;
741 }
742
743 ffclock_updated = 0;
744 }
745 if (++ogen == 0)
746 ogen = 1;
747 ffth->gen = ogen;
748 fftimehands = ffth;
749 }
750
751 /*
752 * Adjust the fftimehands when the timecounter is changed. Stating the obvious,
753 * the old and new hardware counter cannot be read simultaneously. tc_windup()
754 * does read the two counters 'back to back', but a few cycles are effectively
755 * lost, and not accumulated in tick_ffcount. This is a fairly radical
756 * operation for a feed-forward synchronization daemon, and it is its job to not
757 * pushing irrelevant data to the kernel. Because there is no locking here,
758 * simply force to ignore pending or next update to give daemon a chance to
759 * realize the counter has changed.
760 */
761 static void
762 ffclock_change_tc(struct timehands *th)
763 {
764 struct fftimehands *ffth;
765 struct ffclock_estimate *cest;
766 struct timecounter *tc;
767 uint8_t ogen;
768
769 tc = th->th_counter;
770 ffth = fftimehands->next;
771 ogen = ffth->gen;
772 ffth->gen = 0;
773
774 cest = &ffth->cest;
775 bcopy(&(fftimehands->cest), cest, sizeof(struct ffclock_estimate));
776 cest->period = ((1ULL << 63) / tc->tc_frequency ) << 1;
777 cest->errb_abs = 0;
778 cest->errb_rate = 0;
779 cest->status |= FFCLOCK_STA_UNSYNC;
780
781 ffth->tick_ffcount = fftimehands->tick_ffcount;
782 ffth->tick_time_lerp = fftimehands->tick_time_lerp;
783 ffth->tick_time = fftimehands->tick_time;
784 ffth->period_lerp = cest->period;
785
786 /* Do not lock but ignore next update from synchronization daemon. */
787 ffclock_updated--;
788
789 if (++ogen == 0)
790 ogen = 1;
791 ffth->gen = ogen;
792 fftimehands = ffth;
793 }
794
795 /*
796 * Retrieve feed-forward counter and time of last kernel tick.
797 */
798 void
799 ffclock_last_tick(ffcounter *ffcount, struct bintime *bt, uint32_t flags)
800 {
801 struct fftimehands *ffth;
802 uint8_t gen;
803
804 /*
805 * No locking but check generation has not changed. Also need to make
806 * sure ffdelta is positive, i.e. ffcount > tick_ffcount.
807 */
808 do {
809 ffth = fftimehands;
810 gen = ffth->gen;
811 if ((flags & FFCLOCK_LERP) == FFCLOCK_LERP)
812 *bt = ffth->tick_time_lerp;
813 else
814 *bt = ffth->tick_time;
815 *ffcount = ffth->tick_ffcount;
816 } while (gen == 0 || gen != ffth->gen);
817 }
818
819 /*
820 * Absolute clock conversion. Low level function to convert ffcounter to
821 * bintime. The ffcounter is converted using the current ffclock period estimate
822 * or the "interpolated period" to ensure monotonicity.
823 * NOTE: this conversion may have been deferred, and the clock updated since the
824 * hardware counter has been read.
825 */
826 void
827 ffclock_convert_abs(ffcounter ffcount, struct bintime *bt, uint32_t flags)
828 {
829 struct fftimehands *ffth;
830 struct bintime bt2;
831 ffcounter ffdelta;
832 uint8_t gen;
833
834 /*
835 * No locking but check generation has not changed. Also need to make
836 * sure ffdelta is positive, i.e. ffcount > tick_ffcount.
837 */
838 do {
839 ffth = fftimehands;
840 gen = ffth->gen;
841 if (ffcount > ffth->tick_ffcount)
842 ffdelta = ffcount - ffth->tick_ffcount;
843 else
844 ffdelta = ffth->tick_ffcount - ffcount;
845
846 if ((flags & FFCLOCK_LERP) == FFCLOCK_LERP) {
847 *bt = ffth->tick_time_lerp;
848 ffclock_convert_delta(ffdelta, ffth->period_lerp, &bt2);
849 } else {
850 *bt = ffth->tick_time;
851 ffclock_convert_delta(ffdelta, ffth->cest.period, &bt2);
852 }
853
854 if (ffcount > ffth->tick_ffcount)
855 bintime_add(bt, &bt2);
856 else
857 bintime_sub(bt, &bt2);
858 } while (gen == 0 || gen != ffth->gen);
859 }
860
861 /*
862 * Difference clock conversion.
863 * Low level function to Convert a time interval measured in RAW counter units
864 * into bintime. The difference clock allows measuring small intervals much more
865 * reliably than the absolute clock.
866 */
867 void
868 ffclock_convert_diff(ffcounter ffdelta, struct bintime *bt)
869 {
870 struct fftimehands *ffth;
871 uint8_t gen;
872
873 /* No locking but check generation has not changed. */
874 do {
875 ffth = fftimehands;
876 gen = ffth->gen;
877 ffclock_convert_delta(ffdelta, ffth->cest.period, bt);
878 } while (gen == 0 || gen != ffth->gen);
879 }
880
881 /*
882 * Access to current ffcounter value.
883 */
884 void
885 ffclock_read_counter(ffcounter *ffcount)
886 {
887 struct timehands *th;
888 struct fftimehands *ffth;
889 unsigned int gen, delta;
890
891 /*
892 * ffclock_windup() called from tc_windup(), safe to rely on
893 * th->th_generation only, for correct delta and ffcounter.
894 */
895 do {
896 th = timehands;
897 gen = atomic_load_acq_int(&th->th_generation);
898 ffth = fftimehands;
899 delta = tc_delta(th);
900 *ffcount = ffth->tick_ffcount;
901 atomic_thread_fence_acq();
902 } while (gen == 0 || gen != th->th_generation);
903
904 *ffcount += delta;
905 }
906
907 void
908 binuptime(struct bintime *bt)
909 {
910
911 binuptime_fromclock(bt, sysclock_active);
912 }
913
914 void
915 nanouptime(struct timespec *tsp)
916 {
917
918 nanouptime_fromclock(tsp, sysclock_active);
919 }
920
921 void
922 microuptime(struct timeval *tvp)
923 {
924
925 microuptime_fromclock(tvp, sysclock_active);
926 }
927
928 void
929 bintime(struct bintime *bt)
930 {
931
932 bintime_fromclock(bt, sysclock_active);
933 }
934
935 void
936 nanotime(struct timespec *tsp)
937 {
938
939 nanotime_fromclock(tsp, sysclock_active);
940 }
941
942 void
943 microtime(struct timeval *tvp)
944 {
945
946 microtime_fromclock(tvp, sysclock_active);
947 }
948
949 void
950 getbinuptime(struct bintime *bt)
951 {
952
953 getbinuptime_fromclock(bt, sysclock_active);
954 }
955
956 void
957 getnanouptime(struct timespec *tsp)
958 {
959
960 getnanouptime_fromclock(tsp, sysclock_active);
961 }
962
963 void
964 getmicrouptime(struct timeval *tvp)
965 {
966
967 getmicrouptime_fromclock(tvp, sysclock_active);
968 }
969
970 void
971 getbintime(struct bintime *bt)
972 {
973
974 getbintime_fromclock(bt, sysclock_active);
975 }
976
977 void
978 getnanotime(struct timespec *tsp)
979 {
980
981 getnanotime_fromclock(tsp, sysclock_active);
982 }
983
984 void
985 getmicrotime(struct timeval *tvp)
986 {
987
988 getmicrouptime_fromclock(tvp, sysclock_active);
989 }
990
991 #endif /* FFCLOCK */
992
993 /*
994 * This is a clone of getnanotime and used for walltimestamps.
995 * The dtrace_ prefix prevents fbt from creating probes for
996 * it so walltimestamp can be safely used in all fbt probes.
997 */
998 void
999 dtrace_getnanotime(struct timespec *tsp)
1000 {
1001
1002 GETTHMEMBER(tsp, th_nanotime);
1003 }
1004
1005 /*
1006 * This is a clone of getnanouptime used for time since boot.
1007 * The dtrace_ prefix prevents fbt from creating probes for
1008 * it so an uptime that can be safely used in all fbt probes.
1009 */
1010 void
1011 dtrace_getnanouptime(struct timespec *tsp)
1012 {
1013 struct bintime bt;
1014
1015 GETTHMEMBER(&bt, th_offset);
1016 bintime2timespec(&bt, tsp);
1017 }
1018
1019 /*
1020 * System clock currently providing time to the system. Modifiable via sysctl
1021 * when the FFCLOCK option is defined.
1022 */
1023 int sysclock_active = SYSCLOCK_FBCK;
1024
1025 /* Internal NTP status and error estimates. */
1026 extern int time_status;
1027 extern long time_esterror;
1028
1029 /*
1030 * Take a snapshot of sysclock data which can be used to compare system clocks
1031 * and generate timestamps after the fact.
1032 */
1033 void
1034 sysclock_getsnapshot(struct sysclock_snap *clock_snap, int fast)
1035 {
1036 struct fbclock_info *fbi;
1037 struct timehands *th;
1038 struct bintime bt;
1039 unsigned int delta, gen;
1040 #ifdef FFCLOCK
1041 ffcounter ffcount;
1042 struct fftimehands *ffth;
1043 struct ffclock_info *ffi;
1044 struct ffclock_estimate cest;
1045
1046 ffi = &clock_snap->ff_info;
1047 #endif
1048
1049 fbi = &clock_snap->fb_info;
1050 delta = 0;
1051
1052 do {
1053 th = timehands;
1054 gen = atomic_load_acq_int(&th->th_generation);
1055 fbi->th_scale = th->th_scale;
1056 fbi->tick_time = th->th_offset;
1057 #ifdef FFCLOCK
1058 ffth = fftimehands;
1059 ffi->tick_time = ffth->tick_time_lerp;
1060 ffi->tick_time_lerp = ffth->tick_time_lerp;
1061 ffi->period = ffth->cest.period;
1062 ffi->period_lerp = ffth->period_lerp;
1063 clock_snap->ffcount = ffth->tick_ffcount;
1064 cest = ffth->cest;
1065 #endif
1066 if (!fast)
1067 delta = tc_delta(th);
1068 atomic_thread_fence_acq();
1069 } while (gen == 0 || gen != th->th_generation);
1070
1071 clock_snap->delta = delta;
1072 clock_snap->sysclock_active = sysclock_active;
1073
1074 /* Record feedback clock status and error. */
1075 clock_snap->fb_info.status = time_status;
1076 /* XXX: Very crude estimate of feedback clock error. */
1077 bt.sec = time_esterror / 1000000;
1078 bt.frac = ((time_esterror - bt.sec) * 1000000) *
1079 (uint64_t)18446744073709ULL;
1080 clock_snap->fb_info.error = bt;
1081
1082 #ifdef FFCLOCK
1083 if (!fast)
1084 clock_snap->ffcount += delta;
1085
1086 /* Record feed-forward clock leap second adjustment. */
1087 ffi->leapsec_adjustment = cest.leapsec_total;
1088 if (clock_snap->ffcount > cest.leapsec_next)
1089 ffi->leapsec_adjustment -= cest.leapsec;
1090
1091 /* Record feed-forward clock status and error. */
1092 clock_snap->ff_info.status = cest.status;
1093 ffcount = clock_snap->ffcount - cest.update_ffcount;
1094 ffclock_convert_delta(ffcount, cest.period, &bt);
1095 /* 18446744073709 = int(2^64/1e12), err_bound_rate in [ps/s]. */
1096 bintime_mul(&bt, cest.errb_rate * (uint64_t)18446744073709ULL);
1097 /* 18446744073 = int(2^64 / 1e9), since err_abs in [ns]. */
1098 bintime_addx(&bt, cest.errb_abs * (uint64_t)18446744073ULL);
1099 clock_snap->ff_info.error = bt;
1100 #endif
1101 }
1102
1103 /*
1104 * Convert a sysclock snapshot into a struct bintime based on the specified
1105 * clock source and flags.
1106 */
1107 int
1108 sysclock_snap2bintime(struct sysclock_snap *cs, struct bintime *bt,
1109 int whichclock, uint32_t flags)
1110 {
1111 struct bintime boottimebin;
1112 #ifdef FFCLOCK
1113 struct bintime bt2;
1114 uint64_t period;
1115 #endif
1116
1117 switch (whichclock) {
1118 case SYSCLOCK_FBCK:
1119 *bt = cs->fb_info.tick_time;
1120
1121 /* If snapshot was created with !fast, delta will be >0. */
1122 if (cs->delta > 0)
1123 bintime_addx(bt, cs->fb_info.th_scale * cs->delta);
1124
1125 if ((flags & FBCLOCK_UPTIME) == 0) {
1126 getboottimebin(&boottimebin);
1127 bintime_add(bt, &boottimebin);
1128 }
1129 break;
1130 #ifdef FFCLOCK
1131 case SYSCLOCK_FFWD:
1132 if (flags & FFCLOCK_LERP) {
1133 *bt = cs->ff_info.tick_time_lerp;
1134 period = cs->ff_info.period_lerp;
1135 } else {
1136 *bt = cs->ff_info.tick_time;
1137 period = cs->ff_info.period;
1138 }
1139
1140 /* If snapshot was created with !fast, delta will be >0. */
1141 if (cs->delta > 0) {
1142 ffclock_convert_delta(cs->delta, period, &bt2);
1143 bintime_add(bt, &bt2);
1144 }
1145
1146 /* Leap second adjustment. */
1147 if (flags & FFCLOCK_LEAPSEC)
1148 bt->sec -= cs->ff_info.leapsec_adjustment;
1149
1150 /* Boot time adjustment, for uptime/monotonic clocks. */
1151 if (flags & FFCLOCK_UPTIME)
1152 bintime_sub(bt, &ffclock_boottime);
1153 break;
1154 #endif
1155 default:
1156 return (EINVAL);
1157 break;
1158 }
1159
1160 return (0);
1161 }
1162
1163 /*
1164 * Initialize a new timecounter and possibly use it.
1165 */
1166 void
1167 tc_init(struct timecounter *tc)
1168 {
1169 u_int u;
1170 struct sysctl_oid *tc_root;
1171
1172 u = tc->tc_frequency / tc->tc_counter_mask;
1173 /* XXX: We need some margin here, 10% is a guess */
1174 u *= 11;
1175 u /= 10;
1176 if (u > hz && tc->tc_quality >= 0) {
1177 tc->tc_quality = -2000;
1178 if (bootverbose) {
1179 printf("Timecounter \"%s\" frequency %ju Hz",
1180 tc->tc_name, (uintmax_t)tc->tc_frequency);
1181 printf(" -- Insufficient hz, needs at least %u\n", u);
1182 }
1183 } else if (tc->tc_quality >= 0 || bootverbose) {
1184 printf("Timecounter \"%s\" frequency %ju Hz quality %d\n",
1185 tc->tc_name, (uintmax_t)tc->tc_frequency,
1186 tc->tc_quality);
1187 }
1188
1189 /*
1190 * Set up sysctl tree for this counter.
1191 */
1192 tc_root = SYSCTL_ADD_NODE_WITH_LABEL(NULL,
1193 SYSCTL_STATIC_CHILDREN(_kern_timecounter_tc), OID_AUTO, tc->tc_name,
1194 CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
1195 "timecounter description", "timecounter");
1196 SYSCTL_ADD_UINT(NULL, SYSCTL_CHILDREN(tc_root), OID_AUTO,
1197 "mask", CTLFLAG_RD, &(tc->tc_counter_mask), 0,
1198 "mask for implemented bits");
1199 SYSCTL_ADD_PROC(NULL, SYSCTL_CHILDREN(tc_root), OID_AUTO,
1200 "counter", CTLTYPE_UINT | CTLFLAG_RD | CTLFLAG_MPSAFE, tc,
1201 sizeof(*tc), sysctl_kern_timecounter_get, "IU",
1202 "current timecounter value");
1203 SYSCTL_ADD_PROC(NULL, SYSCTL_CHILDREN(tc_root), OID_AUTO,
1204 "frequency", CTLTYPE_U64 | CTLFLAG_RD | CTLFLAG_MPSAFE, tc,
1205 sizeof(*tc), sysctl_kern_timecounter_freq, "QU",
1206 "timecounter frequency");
1207 SYSCTL_ADD_INT(NULL, SYSCTL_CHILDREN(tc_root), OID_AUTO,
1208 "quality", CTLFLAG_RD, &(tc->tc_quality), 0,
1209 "goodness of time counter");
1210
1211 mtx_lock(&tc_lock);
1212 tc->tc_next = timecounters;
1213 timecounters = tc;
1214
1215 /*
1216 * Do not automatically switch if the current tc was specifically
1217 * chosen. Never automatically use a timecounter with negative quality.
1218 * Even though we run on the dummy counter, switching here may be
1219 * worse since this timecounter may not be monotonic.
1220 */
1221 if (tc_chosen)
1222 goto unlock;
1223 if (tc->tc_quality < 0)
1224 goto unlock;
1225 if (tc_from_tunable[0] != '\0' &&
1226 strcmp(tc->tc_name, tc_from_tunable) == 0) {
1227 tc_chosen = 1;
1228 tc_from_tunable[0] = '\0';
1229 } else {
1230 if (tc->tc_quality < timecounter->tc_quality)
1231 goto unlock;
1232 if (tc->tc_quality == timecounter->tc_quality &&
1233 tc->tc_frequency < timecounter->tc_frequency)
1234 goto unlock;
1235 }
1236 (void)tc->tc_get_timecount(tc);
1237 timecounter = tc;
1238 unlock:
1239 mtx_unlock(&tc_lock);
1240 }
1241
1242 /* Report the frequency of the current timecounter. */
1243 uint64_t
1244 tc_getfrequency(void)
1245 {
1246
1247 return (timehands->th_counter->tc_frequency);
1248 }
1249
1250 static bool
1251 sleeping_on_old_rtc(struct thread *td)
1252 {
1253
1254 /*
1255 * td_rtcgen is modified by curthread when it is running,
1256 * and by other threads in this function. By finding the thread
1257 * on a sleepqueue and holding the lock on the sleepqueue
1258 * chain, we guarantee that the thread is not running and that
1259 * modifying td_rtcgen is safe. Setting td_rtcgen to zero informs
1260 * the thread that it was woken due to a real-time clock adjustment.
1261 * (The declaration of td_rtcgen refers to this comment.)
1262 */
1263 if (td->td_rtcgen != 0 && td->td_rtcgen != rtc_generation) {
1264 td->td_rtcgen = 0;
1265 return (true);
1266 }
1267 return (false);
1268 }
1269
1270 static struct mtx tc_setclock_mtx;
1271 MTX_SYSINIT(tc_setclock_init, &tc_setclock_mtx, "tcsetc", MTX_SPIN);
1272
1273 /*
1274 * Step our concept of UTC. This is done by modifying our estimate of
1275 * when we booted.
1276 */
1277 void
1278 tc_setclock(struct timespec *ts)
1279 {
1280 struct timespec tbef, taft;
1281 struct bintime bt, bt2;
1282
1283 timespec2bintime(ts, &bt);
1284 nanotime(&tbef);
1285 mtx_lock_spin(&tc_setclock_mtx);
1286 cpu_tick_calibrate(1);
1287 binuptime(&bt2);
1288 bintime_sub(&bt, &bt2);
1289
1290 /* XXX fiddle all the little crinkly bits around the fiords... */
1291 tc_windup(&bt);
1292 mtx_unlock_spin(&tc_setclock_mtx);
1293
1294 /* Avoid rtc_generation == 0, since td_rtcgen == 0 is special. */
1295 atomic_add_rel_int(&rtc_generation, 2);
1296 sleepq_chains_remove_matching(sleeping_on_old_rtc);
1297 if (timestepwarnings) {
1298 nanotime(&taft);
1299 log(LOG_INFO,
1300 "Time stepped from %jd.%09ld to %jd.%09ld (%jd.%09ld)\n",
1301 (intmax_t)tbef.tv_sec, tbef.tv_nsec,
1302 (intmax_t)taft.tv_sec, taft.tv_nsec,
1303 (intmax_t)ts->tv_sec, ts->tv_nsec);
1304 }
1305 }
1306
1307 /*
1308 * Recalculate the scaling factor. We want the number of 1/2^64
1309 * fractions of a second per period of the hardware counter, taking
1310 * into account the th_adjustment factor which the NTP PLL/adjtime(2)
1311 * processing provides us with.
1312 *
1313 * The th_adjustment is nanoseconds per second with 32 bit binary
1314 * fraction and we want 64 bit binary fraction of second:
1315 *
1316 * x = a * 2^32 / 10^9 = a * 4.294967296
1317 *
1318 * The range of th_adjustment is +/- 5000PPM so inside a 64bit int
1319 * we can only multiply by about 850 without overflowing, that
1320 * leaves no suitably precise fractions for multiply before divide.
1321 *
1322 * Divide before multiply with a fraction of 2199/512 results in a
1323 * systematic undercompensation of 10PPM of th_adjustment. On a
1324 * 5000PPM adjustment this is a 0.05PPM error. This is acceptable.
1325 *
1326 * We happily sacrifice the lowest of the 64 bits of our result
1327 * to the goddess of code clarity.
1328 */
1329 static void
1330 recalculate_scaling_factor_and_large_delta(struct timehands *th)
1331 {
1332 uint64_t scale;
1333
1334 scale = (uint64_t)1 << 63;
1335 scale += (th->th_adjustment / 1024) * 2199;
1336 scale /= th->th_counter->tc_frequency;
1337 th->th_scale = scale * 2;
1338 th->th_large_delta = MIN(((uint64_t)1 << 63) / scale, UINT_MAX);
1339 }
1340
1341 /*
1342 * Initialize the next struct timehands in the ring and make
1343 * it the active timehands. Along the way we might switch to a different
1344 * timecounter and/or do seconds processing in NTP. Slightly magic.
1345 */
1346 static void
1347 tc_windup(struct bintime *new_boottimebin)
1348 {
1349 struct bintime bt;
1350 struct timehands *th, *tho;
1351 u_int delta, ncount, ogen;
1352 int i;
1353 time_t t;
1354
1355 /*
1356 * Make the next timehands a copy of the current one, but do
1357 * not overwrite the generation or next pointer. While we
1358 * update the contents, the generation must be zero. We need
1359 * to ensure that the zero generation is visible before the
1360 * data updates become visible, which requires release fence.
1361 * For similar reasons, re-reading of the generation after the
1362 * data is read should use acquire fence.
1363 */
1364 tho = timehands;
1365 th = tho->th_next;
1366 ogen = th->th_generation;
1367 th->th_generation = 0;
1368 atomic_thread_fence_rel();
1369 memcpy(th, tho, offsetof(struct timehands, th_generation));
1370 if (new_boottimebin != NULL)
1371 th->th_boottime = *new_boottimebin;
1372
1373 /*
1374 * Capture a timecounter delta on the current timecounter and if
1375 * changing timecounters, a counter value from the new timecounter.
1376 * Update the offset fields accordingly.
1377 */
1378 delta = tc_delta(th);
1379 if (th->th_counter != timecounter)
1380 ncount = timecounter->tc_get_timecount(timecounter);
1381 else
1382 ncount = 0;
1383 #ifdef FFCLOCK
1384 ffclock_windup(delta);
1385 #endif
1386 th->th_offset_count += delta;
1387 th->th_offset_count &= th->th_counter->tc_counter_mask;
1388 while (delta > th->th_counter->tc_frequency) {
1389 /* Eat complete unadjusted seconds. */
1390 delta -= th->th_counter->tc_frequency;
1391 th->th_offset.sec++;
1392 }
1393 if ((delta > th->th_counter->tc_frequency / 2) &&
1394 (th->th_scale * delta < ((uint64_t)1 << 63))) {
1395 /* The product th_scale * delta just barely overflows. */
1396 th->th_offset.sec++;
1397 }
1398 bintime_addx(&th->th_offset, th->th_scale * delta);
1399
1400 /*
1401 * Hardware latching timecounters may not generate interrupts on
1402 * PPS events, so instead we poll them. There is a finite risk that
1403 * the hardware might capture a count which is later than the one we
1404 * got above, and therefore possibly in the next NTP second which might
1405 * have a different rate than the current NTP second. It doesn't
1406 * matter in practice.
1407 */
1408 if (tho->th_counter->tc_poll_pps)
1409 tho->th_counter->tc_poll_pps(tho->th_counter);
1410
1411 /*
1412 * Deal with NTP second processing. The loop normally
1413 * iterates at most once, but in extreme situations it might
1414 * keep NTP sane if timeouts are not run for several seconds.
1415 * At boot, the time step can be large when the TOD hardware
1416 * has been read, so on really large steps, we call
1417 * ntp_update_second only twice. We need to call it twice in
1418 * case we missed a leap second.
1419 */
1420 bt = th->th_offset;
1421 bintime_add(&bt, &th->th_boottime);
1422 i = bt.sec - tho->th_microtime.tv_sec;
1423 if (i > 0) {
1424 if (i > LARGE_STEP)
1425 i = 2;
1426
1427 do {
1428 t = bt.sec;
1429 ntp_update_second(&th->th_adjustment, &bt.sec);
1430 if (bt.sec != t)
1431 th->th_boottime.sec += bt.sec - t;
1432 --i;
1433 } while (i > 0);
1434
1435 recalculate_scaling_factor_and_large_delta(th);
1436 }
1437
1438 /* Update the UTC timestamps used by the get*() functions. */
1439 th->th_bintime = bt;
1440 bintime2timeval(&bt, &th->th_microtime);
1441 bintime2timespec(&bt, &th->th_nanotime);
1442
1443 /* Now is a good time to change timecounters. */
1444 if (th->th_counter != timecounter) {
1445 #ifndef __arm__
1446 if ((timecounter->tc_flags & TC_FLAGS_C2STOP) != 0)
1447 cpu_disable_c2_sleep++;
1448 if ((th->th_counter->tc_flags & TC_FLAGS_C2STOP) != 0)
1449 cpu_disable_c2_sleep--;
1450 #endif
1451 th->th_counter = timecounter;
1452 th->th_offset_count = ncount;
1453 tc_min_ticktock_freq = max(1, timecounter->tc_frequency /
1454 (((uint64_t)timecounter->tc_counter_mask + 1) / 3));
1455 recalculate_scaling_factor_and_large_delta(th);
1456 #ifdef FFCLOCK
1457 ffclock_change_tc(th);
1458 #endif
1459 }
1460
1461 /*
1462 * Now that the struct timehands is again consistent, set the new
1463 * generation number, making sure to not make it zero.
1464 */
1465 if (++ogen == 0)
1466 ogen = 1;
1467 atomic_store_rel_int(&th->th_generation, ogen);
1468
1469 /* Go live with the new struct timehands. */
1470 #ifdef FFCLOCK
1471 switch (sysclock_active) {
1472 case SYSCLOCK_FBCK:
1473 #endif
1474 time_second = th->th_microtime.tv_sec;
1475 time_uptime = th->th_offset.sec;
1476 #ifdef FFCLOCK
1477 break;
1478 case SYSCLOCK_FFWD:
1479 time_second = fftimehands->tick_time_lerp.sec;
1480 time_uptime = fftimehands->tick_time_lerp.sec - ffclock_boottime.sec;
1481 break;
1482 }
1483 #endif
1484
1485 timehands = th;
1486 timekeep_push_vdso();
1487 }
1488
1489 /* Report or change the active timecounter hardware. */
1490 static int
1491 sysctl_kern_timecounter_hardware(SYSCTL_HANDLER_ARGS)
1492 {
1493 char newname[32];
1494 struct timecounter *newtc, *tc;
1495 int error;
1496
1497 mtx_lock(&tc_lock);
1498 tc = timecounter;
1499 strlcpy(newname, tc->tc_name, sizeof(newname));
1500 mtx_unlock(&tc_lock);
1501
1502 error = sysctl_handle_string(oidp, &newname[0], sizeof(newname), req);
1503 if (error != 0 || req->newptr == NULL)
1504 return (error);
1505
1506 mtx_lock(&tc_lock);
1507 /* Record that the tc in use now was specifically chosen. */
1508 tc_chosen = 1;
1509 if (strcmp(newname, tc->tc_name) == 0) {
1510 mtx_unlock(&tc_lock);
1511 return (0);
1512 }
1513 for (newtc = timecounters; newtc != NULL; newtc = newtc->tc_next) {
1514 if (strcmp(newname, newtc->tc_name) != 0)
1515 continue;
1516
1517 /* Warm up new timecounter. */
1518 (void)newtc->tc_get_timecount(newtc);
1519
1520 timecounter = newtc;
1521
1522 /*
1523 * The vdso timehands update is deferred until the next
1524 * 'tc_windup()'.
1525 *
1526 * This is prudent given that 'timekeep_push_vdso()' does not
1527 * use any locking and that it can be called in hard interrupt
1528 * context via 'tc_windup()'.
1529 */
1530 break;
1531 }
1532 mtx_unlock(&tc_lock);
1533 return (newtc != NULL ? 0 : EINVAL);
1534 }
1535 SYSCTL_PROC(_kern_timecounter, OID_AUTO, hardware,
1536 CTLTYPE_STRING | CTLFLAG_RWTUN | CTLFLAG_NOFETCH | CTLFLAG_MPSAFE, 0, 0,
1537 sysctl_kern_timecounter_hardware, "A",
1538 "Timecounter hardware selected");
1539
1540 /* Report the available timecounter hardware. */
1541 static int
1542 sysctl_kern_timecounter_choice(SYSCTL_HANDLER_ARGS)
1543 {
1544 struct sbuf sb;
1545 struct timecounter *tc;
1546 int error;
1547
1548 error = sysctl_wire_old_buffer(req, 0);
1549 if (error != 0)
1550 return (error);
1551 sbuf_new_for_sysctl(&sb, NULL, 0, req);
1552 mtx_lock(&tc_lock);
1553 for (tc = timecounters; tc != NULL; tc = tc->tc_next) {
1554 if (tc != timecounters)
1555 sbuf_putc(&sb, ' ');
1556 sbuf_printf(&sb, "%s(%d)", tc->tc_name, tc->tc_quality);
1557 }
1558 mtx_unlock(&tc_lock);
1559 error = sbuf_finish(&sb);
1560 sbuf_delete(&sb);
1561 return (error);
1562 }
1563
1564 SYSCTL_PROC(_kern_timecounter, OID_AUTO, choice,
1565 CTLTYPE_STRING | CTLFLAG_RD | CTLFLAG_MPSAFE, 0, 0,
1566 sysctl_kern_timecounter_choice, "A",
1567 "Timecounter hardware detected");
1568
1569 /*
1570 * RFC 2783 PPS-API implementation.
1571 */
1572
1573 /*
1574 * Return true if the driver is aware of the abi version extensions in the
1575 * pps_state structure, and it supports at least the given abi version number.
1576 */
1577 static inline int
1578 abi_aware(struct pps_state *pps, int vers)
1579 {
1580
1581 return ((pps->kcmode & KCMODE_ABIFLAG) && pps->driver_abi >= vers);
1582 }
1583
1584 static int
1585 pps_fetch(struct pps_fetch_args *fapi, struct pps_state *pps)
1586 {
1587 int err, timo;
1588 pps_seq_t aseq, cseq;
1589 struct timeval tv;
1590
1591 if (fapi->tsformat && fapi->tsformat != PPS_TSFMT_TSPEC)
1592 return (EINVAL);
1593
1594 /*
1595 * If no timeout is requested, immediately return whatever values were
1596 * most recently captured. If timeout seconds is -1, that's a request
1597 * to block without a timeout. WITNESS won't let us sleep forever
1598 * without a lock (we really don't need a lock), so just repeatedly
1599 * sleep a long time.
1600 */
1601 if (fapi->timeout.tv_sec || fapi->timeout.tv_nsec) {
1602 if (fapi->timeout.tv_sec == -1)
1603 timo = 0x7fffffff;
1604 else {
1605 tv.tv_sec = fapi->timeout.tv_sec;
1606 tv.tv_usec = fapi->timeout.tv_nsec / 1000;
1607 timo = tvtohz(&tv);
1608 }
1609 aseq = atomic_load_int(&pps->ppsinfo.assert_sequence);
1610 cseq = atomic_load_int(&pps->ppsinfo.clear_sequence);
1611 while (aseq == atomic_load_int(&pps->ppsinfo.assert_sequence) &&
1612 cseq == atomic_load_int(&pps->ppsinfo.clear_sequence)) {
1613 if (abi_aware(pps, 1) && pps->driver_mtx != NULL) {
1614 if (pps->flags & PPSFLAG_MTX_SPIN) {
1615 err = msleep_spin(pps, pps->driver_mtx,
1616 "ppsfch", timo);
1617 } else {
1618 err = msleep(pps, pps->driver_mtx, PCATCH,
1619 "ppsfch", timo);
1620 }
1621 } else {
1622 err = tsleep(pps, PCATCH, "ppsfch", timo);
1623 }
1624 if (err == EWOULDBLOCK) {
1625 if (fapi->timeout.tv_sec == -1) {
1626 continue;
1627 } else {
1628 return (ETIMEDOUT);
1629 }
1630 } else if (err != 0) {
1631 return (err);
1632 }
1633 }
1634 }
1635
1636 pps->ppsinfo.current_mode = pps->ppsparam.mode;
1637 fapi->pps_info_buf = pps->ppsinfo;
1638
1639 return (0);
1640 }
1641
1642 int
1643 pps_ioctl(u_long cmd, caddr_t data, struct pps_state *pps)
1644 {
1645 pps_params_t *app;
1646 struct pps_fetch_args *fapi;
1647 #ifdef FFCLOCK
1648 struct pps_fetch_ffc_args *fapi_ffc;
1649 #endif
1650 #ifdef PPS_SYNC
1651 struct pps_kcbind_args *kapi;
1652 #endif
1653
1654 KASSERT(pps != NULL, ("NULL pps pointer in pps_ioctl"));
1655 switch (cmd) {
1656 case PPS_IOC_CREATE:
1657 return (0);
1658 case PPS_IOC_DESTROY:
1659 return (0);
1660 case PPS_IOC_SETPARAMS:
1661 app = (pps_params_t *)data;
1662 if (app->mode & ~pps->ppscap)
1663 return (EINVAL);
1664 #ifdef FFCLOCK
1665 /* Ensure only a single clock is selected for ffc timestamp. */
1666 if ((app->mode & PPS_TSCLK_MASK) == PPS_TSCLK_MASK)
1667 return (EINVAL);
1668 #endif
1669 pps->ppsparam = *app;
1670 return (0);
1671 case PPS_IOC_GETPARAMS:
1672 app = (pps_params_t *)data;
1673 *app = pps->ppsparam;
1674 app->api_version = PPS_API_VERS_1;
1675 return (0);
1676 case PPS_IOC_GETCAP:
1677 *(int*)data = pps->ppscap;
1678 return (0);
1679 case PPS_IOC_FETCH:
1680 fapi = (struct pps_fetch_args *)data;
1681 return (pps_fetch(fapi, pps));
1682 #ifdef FFCLOCK
1683 case PPS_IOC_FETCH_FFCOUNTER:
1684 fapi_ffc = (struct pps_fetch_ffc_args *)data;
1685 if (fapi_ffc->tsformat && fapi_ffc->tsformat !=
1686 PPS_TSFMT_TSPEC)
1687 return (EINVAL);
1688 if (fapi_ffc->timeout.tv_sec || fapi_ffc->timeout.tv_nsec)
1689 return (EOPNOTSUPP);
1690 pps->ppsinfo_ffc.current_mode = pps->ppsparam.mode;
1691 fapi_ffc->pps_info_buf_ffc = pps->ppsinfo_ffc;
1692 /* Overwrite timestamps if feedback clock selected. */
1693 switch (pps->ppsparam.mode & PPS_TSCLK_MASK) {
1694 case PPS_TSCLK_FBCK:
1695 fapi_ffc->pps_info_buf_ffc.assert_timestamp =
1696 pps->ppsinfo.assert_timestamp;
1697 fapi_ffc->pps_info_buf_ffc.clear_timestamp =
1698 pps->ppsinfo.clear_timestamp;
1699 break;
1700 case PPS_TSCLK_FFWD:
1701 break;
1702 default:
1703 break;
1704 }
1705 return (0);
1706 #endif /* FFCLOCK */
1707 case PPS_IOC_KCBIND:
1708 #ifdef PPS_SYNC
1709 kapi = (struct pps_kcbind_args *)data;
1710 /* XXX Only root should be able to do this */
1711 if (kapi->tsformat && kapi->tsformat != PPS_TSFMT_TSPEC)
1712 return (EINVAL);
1713 if (kapi->kernel_consumer != PPS_KC_HARDPPS)
1714 return (EINVAL);
1715 if (kapi->edge & ~pps->ppscap)
1716 return (EINVAL);
1717 pps->kcmode = (kapi->edge & KCMODE_EDGEMASK) |
1718 (pps->kcmode & KCMODE_ABIFLAG);
1719 return (0);
1720 #else
1721 return (EOPNOTSUPP);
1722 #endif
1723 default:
1724 return (ENOIOCTL);
1725 }
1726 }
1727
1728 void
1729 pps_init(struct pps_state *pps)
1730 {
1731 pps->ppscap |= PPS_TSFMT_TSPEC | PPS_CANWAIT;
1732 if (pps->ppscap & PPS_CAPTUREASSERT)
1733 pps->ppscap |= PPS_OFFSETASSERT;
1734 if (pps->ppscap & PPS_CAPTURECLEAR)
1735 pps->ppscap |= PPS_OFFSETCLEAR;
1736 #ifdef FFCLOCK
1737 pps->ppscap |= PPS_TSCLK_MASK;
1738 #endif
1739 pps->kcmode &= ~KCMODE_ABIFLAG;
1740 }
1741
1742 void
1743 pps_init_abi(struct pps_state *pps)
1744 {
1745
1746 pps_init(pps);
1747 if (pps->driver_abi > 0) {
1748 pps->kcmode |= KCMODE_ABIFLAG;
1749 pps->kernel_abi = PPS_ABI_VERSION;
1750 }
1751 }
1752
1753 void
1754 pps_capture(struct pps_state *pps)
1755 {
1756 struct timehands *th;
1757
1758 KASSERT(pps != NULL, ("NULL pps pointer in pps_capture"));
1759 th = timehands;
1760 pps->capgen = atomic_load_acq_int(&th->th_generation);
1761 pps->capth = th;
1762 #ifdef FFCLOCK
1763 pps->capffth = fftimehands;
1764 #endif
1765 pps->capcount = th->th_counter->tc_get_timecount(th->th_counter);
1766 atomic_thread_fence_acq();
1767 if (pps->capgen != th->th_generation)
1768 pps->capgen = 0;
1769 }
1770
1771 void
1772 pps_event(struct pps_state *pps, int event)
1773 {
1774 struct bintime bt;
1775 struct timespec ts, *tsp, *osp;
1776 u_int tcount, *pcount;
1777 int foff;
1778 pps_seq_t *pseq;
1779 #ifdef FFCLOCK
1780 struct timespec *tsp_ffc;
1781 pps_seq_t *pseq_ffc;
1782 ffcounter *ffcount;
1783 #endif
1784 #ifdef PPS_SYNC
1785 int fhard;
1786 #endif
1787
1788 KASSERT(pps != NULL, ("NULL pps pointer in pps_event"));
1789 /* Nothing to do if not currently set to capture this event type. */
1790 if ((event & pps->ppsparam.mode) == 0)
1791 return;
1792 /* If the timecounter was wound up underneath us, bail out. */
1793 if (pps->capgen == 0 || pps->capgen !=
1794 atomic_load_acq_int(&pps->capth->th_generation))
1795 return;
1796
1797 /* Things would be easier with arrays. */
1798 if (event == PPS_CAPTUREASSERT) {
1799 tsp = &pps->ppsinfo.assert_timestamp;
1800 osp = &pps->ppsparam.assert_offset;
1801 foff = pps->ppsparam.mode & PPS_OFFSETASSERT;
1802 #ifdef PPS_SYNC
1803 fhard = pps->kcmode & PPS_CAPTUREASSERT;
1804 #endif
1805 pcount = &pps->ppscount[0];
1806 pseq = &pps->ppsinfo.assert_sequence;
1807 #ifdef FFCLOCK
1808 ffcount = &pps->ppsinfo_ffc.assert_ffcount;
1809 tsp_ffc = &pps->ppsinfo_ffc.assert_timestamp;
1810 pseq_ffc = &pps->ppsinfo_ffc.assert_sequence;
1811 #endif
1812 } else {
1813 tsp = &pps->ppsinfo.clear_timestamp;
1814 osp = &pps->ppsparam.clear_offset;
1815 foff = pps->ppsparam.mode & PPS_OFFSETCLEAR;
1816 #ifdef PPS_SYNC
1817 fhard = pps->kcmode & PPS_CAPTURECLEAR;
1818 #endif
1819 pcount = &pps->ppscount[1];
1820 pseq = &pps->ppsinfo.clear_sequence;
1821 #ifdef FFCLOCK
1822 ffcount = &pps->ppsinfo_ffc.clear_ffcount;
1823 tsp_ffc = &pps->ppsinfo_ffc.clear_timestamp;
1824 pseq_ffc = &pps->ppsinfo_ffc.clear_sequence;
1825 #endif
1826 }
1827
1828 /*
1829 * If the timecounter changed, we cannot compare the count values, so
1830 * we have to drop the rest of the PPS-stuff until the next event.
1831 */
1832 if (pps->ppstc != pps->capth->th_counter) {
1833 pps->ppstc = pps->capth->th_counter;
1834 *pcount = pps->capcount;
1835 pps->ppscount[2] = pps->capcount;
1836 return;
1837 }
1838
1839 /* Convert the count to a timespec. */
1840 tcount = pps->capcount - pps->capth->th_offset_count;
1841 tcount &= pps->capth->th_counter->tc_counter_mask;
1842 bt = pps->capth->th_bintime;
1843 bintime_addx(&bt, pps->capth->th_scale * tcount);
1844 bintime2timespec(&bt, &ts);
1845
1846 /* If the timecounter was wound up underneath us, bail out. */
1847 atomic_thread_fence_acq();
1848 if (pps->capgen != pps->capth->th_generation)
1849 return;
1850
1851 *pcount = pps->capcount;
1852 (*pseq)++;
1853 *tsp = ts;
1854
1855 if (foff) {
1856 timespecadd(tsp, osp, tsp);
1857 if (tsp->tv_nsec < 0) {
1858 tsp->tv_nsec += 1000000000;
1859 tsp->tv_sec -= 1;
1860 }
1861 }
1862
1863 #ifdef FFCLOCK
1864 *ffcount = pps->capffth->tick_ffcount + tcount;
1865 bt = pps->capffth->tick_time;
1866 ffclock_convert_delta(tcount, pps->capffth->cest.period, &bt);
1867 bintime_add(&bt, &pps->capffth->tick_time);
1868 bintime2timespec(&bt, &ts);
1869 (*pseq_ffc)++;
1870 *tsp_ffc = ts;
1871 #endif
1872
1873 #ifdef PPS_SYNC
1874 if (fhard) {
1875 uint64_t scale;
1876
1877 /*
1878 * Feed the NTP PLL/FLL.
1879 * The FLL wants to know how many (hardware) nanoseconds
1880 * elapsed since the previous event.
1881 */
1882 tcount = pps->capcount - pps->ppscount[2];
1883 pps->ppscount[2] = pps->capcount;
1884 tcount &= pps->capth->th_counter->tc_counter_mask;
1885 scale = (uint64_t)1 << 63;
1886 scale /= pps->capth->th_counter->tc_frequency;
1887 scale *= 2;
1888 bt.sec = 0;
1889 bt.frac = 0;
1890 bintime_addx(&bt, scale * tcount);
1891 bintime2timespec(&bt, &ts);
1892 hardpps(tsp, ts.tv_nsec + 1000000000 * ts.tv_sec);
1893 }
1894 #endif
1895
1896 /* Wakeup anyone sleeping in pps_fetch(). */
1897 wakeup(pps);
1898 }
1899
1900 /*
1901 * Timecounters need to be updated every so often to prevent the hardware
1902 * counter from overflowing. Updating also recalculates the cached values
1903 * used by the get*() family of functions, so their precision depends on
1904 * the update frequency.
1905 */
1906
1907 static int tc_tick;
1908 SYSCTL_INT(_kern_timecounter, OID_AUTO, tick, CTLFLAG_RD, &tc_tick, 0,
1909 "Approximate number of hardclock ticks in a millisecond");
1910
1911 void
1912 tc_ticktock(int cnt)
1913 {
1914 static int count;
1915
1916 if (mtx_trylock_spin(&tc_setclock_mtx)) {
1917 count += cnt;
1918 if (count >= tc_tick) {
1919 count = 0;
1920 tc_windup(NULL);
1921 }
1922 mtx_unlock_spin(&tc_setclock_mtx);
1923 }
1924 }
1925
1926 static void __inline
1927 tc_adjprecision(void)
1928 {
1929 int t;
1930
1931 if (tc_timepercentage > 0) {
1932 t = (99 + tc_timepercentage) / tc_timepercentage;
1933 tc_precexp = fls(t + (t >> 1)) - 1;
1934 FREQ2BT(hz / tc_tick, &bt_timethreshold);
1935 FREQ2BT(hz, &bt_tickthreshold);
1936 bintime_shift(&bt_timethreshold, tc_precexp);
1937 bintime_shift(&bt_tickthreshold, tc_precexp);
1938 } else {
1939 tc_precexp = 31;
1940 bt_timethreshold.sec = INT_MAX;
1941 bt_timethreshold.frac = ~(uint64_t)0;
1942 bt_tickthreshold = bt_timethreshold;
1943 }
1944 sbt_timethreshold = bttosbt(bt_timethreshold);
1945 sbt_tickthreshold = bttosbt(bt_tickthreshold);
1946 }
1947
1948 static int
1949 sysctl_kern_timecounter_adjprecision(SYSCTL_HANDLER_ARGS)
1950 {
1951 int error, val;
1952
1953 val = tc_timepercentage;
1954 error = sysctl_handle_int(oidp, &val, 0, req);
1955 if (error != 0 || req->newptr == NULL)
1956 return (error);
1957 tc_timepercentage = val;
1958 if (cold)
1959 goto done;
1960 tc_adjprecision();
1961 done:
1962 return (0);
1963 }
1964
1965 /* Set up the requested number of timehands. */
1966 static void
1967 inittimehands(void *dummy)
1968 {
1969 struct timehands *thp;
1970 int i;
1971
1972 TUNABLE_INT_FETCH("kern.timecounter.timehands_count",
1973 &timehands_count);
1974 if (timehands_count < 1)
1975 timehands_count = 1;
1976 if (timehands_count > nitems(ths))
1977 timehands_count = nitems(ths);
1978 for (i = 1, thp = &ths[0]; i < timehands_count; thp = &ths[i++])
1979 thp->th_next = &ths[i];
1980 thp->th_next = &ths[0];
1981
1982 TUNABLE_STR_FETCH("kern.timecounter.hardware", tc_from_tunable,
1983 sizeof(tc_from_tunable));
1984
1985 mtx_init(&tc_lock, "tc", NULL, MTX_DEF);
1986 }
1987 SYSINIT(timehands, SI_SUB_TUNABLES, SI_ORDER_ANY, inittimehands, NULL);
1988
1989 static void
1990 inittimecounter(void *dummy)
1991 {
1992 u_int p;
1993 int tick_rate;
1994
1995 /*
1996 * Set the initial timeout to
1997 * max(1, <approx. number of hardclock ticks in a millisecond>).
1998 * People should probably not use the sysctl to set the timeout
1999 * to smaller than its initial value, since that value is the
2000 * smallest reasonable one. If they want better timestamps they
2001 * should use the non-"get"* functions.
2002 */
2003 if (hz > 1000)
2004 tc_tick = (hz + 500) / 1000;
2005 else
2006 tc_tick = 1;
2007 tc_adjprecision();
2008 FREQ2BT(hz, &tick_bt);
2009 tick_sbt = bttosbt(tick_bt);
2010 tick_rate = hz / tc_tick;
2011 FREQ2BT(tick_rate, &tc_tick_bt);
2012 tc_tick_sbt = bttosbt(tc_tick_bt);
2013 p = (tc_tick * 1000000) / hz;
2014 printf("Timecounters tick every %d.%03u msec\n", p / 1000, p % 1000);
2015
2016 #ifdef FFCLOCK
2017 ffclock_init();
2018 #endif
2019
2020 /* warm up new timecounter (again) and get rolling. */
2021 (void)timecounter->tc_get_timecount(timecounter);
2022 mtx_lock_spin(&tc_setclock_mtx);
2023 tc_windup(NULL);
2024 mtx_unlock_spin(&tc_setclock_mtx);
2025 }
2026
2027 SYSINIT(timecounter, SI_SUB_CLOCKS, SI_ORDER_SECOND, inittimecounter, NULL);
2028
2029 /* Cpu tick handling -------------------------------------------------*/
2030
2031 static int cpu_tick_variable;
2032 static uint64_t cpu_tick_frequency;
2033
2034 DPCPU_DEFINE_STATIC(uint64_t, tc_cpu_ticks_base);
2035 DPCPU_DEFINE_STATIC(unsigned, tc_cpu_ticks_last);
2036
2037 static uint64_t
2038 tc_cpu_ticks(void)
2039 {
2040 struct timecounter *tc;
2041 uint64_t res, *base;
2042 unsigned u, *last;
2043
2044 critical_enter();
2045 base = DPCPU_PTR(tc_cpu_ticks_base);
2046 last = DPCPU_PTR(tc_cpu_ticks_last);
2047 tc = timehands->th_counter;
2048 u = tc->tc_get_timecount(tc) & tc->tc_counter_mask;
2049 if (u < *last)
2050 *base += (uint64_t)tc->tc_counter_mask + 1;
2051 *last = u;
2052 res = u + *base;
2053 critical_exit();
2054 return (res);
2055 }
2056
2057 void
2058 cpu_tick_calibration(void)
2059 {
2060 static time_t last_calib;
2061
2062 if (time_uptime != last_calib && !(time_uptime & 0xf)) {
2063 cpu_tick_calibrate(0);
2064 last_calib = time_uptime;
2065 }
2066 }
2067
2068 /*
2069 * This function gets called every 16 seconds on only one designated
2070 * CPU in the system from hardclock() via cpu_tick_calibration()().
2071 *
2072 * Whenever the real time clock is stepped we get called with reset=1
2073 * to make sure we handle suspend/resume and similar events correctly.
2074 */
2075
2076 static void
2077 cpu_tick_calibrate(int reset)
2078 {
2079 static uint64_t c_last;
2080 uint64_t c_this, c_delta;
2081 static struct bintime t_last;
2082 struct bintime t_this, t_delta;
2083 uint32_t divi;
2084
2085 if (reset) {
2086 /* The clock was stepped, abort & reset */
2087 t_last.sec = 0;
2088 return;
2089 }
2090
2091 /* we don't calibrate fixed rate cputicks */
2092 if (!cpu_tick_variable)
2093 return;
2094
2095 getbinuptime(&t_this);
2096 c_this = cpu_ticks();
2097 if (t_last.sec != 0) {
2098 c_delta = c_this - c_last;
2099 t_delta = t_this;
2100 bintime_sub(&t_delta, &t_last);
2101 /*
2102 * Headroom:
2103 * 2^(64-20) / 16[s] =
2104 * 2^(44) / 16[s] =
2105 * 17.592.186.044.416 / 16 =
2106 * 1.099.511.627.776 [Hz]
2107 */
2108 divi = t_delta.sec << 20;
2109 divi |= t_delta.frac >> (64 - 20);
2110 c_delta <<= 20;
2111 c_delta /= divi;
2112 if (c_delta > cpu_tick_frequency) {
2113 if (0 && bootverbose)
2114 printf("cpu_tick increased to %ju Hz\n",
2115 c_delta);
2116 cpu_tick_frequency = c_delta;
2117 }
2118 }
2119 c_last = c_this;
2120 t_last = t_this;
2121 }
2122
2123 void
2124 set_cputicker(cpu_tick_f *func, uint64_t freq, unsigned var)
2125 {
2126
2127 if (func == NULL) {
2128 cpu_ticks = tc_cpu_ticks;
2129 } else {
2130 cpu_tick_frequency = freq;
2131 cpu_tick_variable = var;
2132 cpu_ticks = func;
2133 }
2134 }
2135
2136 uint64_t
2137 cpu_tickrate(void)
2138 {
2139
2140 if (cpu_ticks == tc_cpu_ticks)
2141 return (tc_getfrequency());
2142 return (cpu_tick_frequency);
2143 }
2144
2145 /*
2146 * We need to be slightly careful converting cputicks to microseconds.
2147 * There is plenty of margin in 64 bits of microseconds (half a million
2148 * years) and in 64 bits at 4 GHz (146 years), but if we do a multiply
2149 * before divide conversion (to retain precision) we find that the
2150 * margin shrinks to 1.5 hours (one millionth of 146y).
2151 * With a three prong approach we never lose significant bits, no
2152 * matter what the cputick rate and length of timeinterval is.
2153 */
2154
2155 uint64_t
2156 cputick2usec(uint64_t tick)
2157 {
2158
2159 if (tick > 18446744073709551LL) /* floor(2^64 / 1000) */
2160 return (tick / (cpu_tickrate() / 1000000LL));
2161 else if (tick > 18446744073709LL) /* floor(2^64 / 1000000) */
2162 return ((tick * 1000LL) / (cpu_tickrate() / 1000LL));
2163 else
2164 return ((tick * 1000000LL) / cpu_tickrate());
2165 }
2166
2167 cpu_tick_f *cpu_ticks = tc_cpu_ticks;
2168
2169 static int vdso_th_enable = 1;
2170 static int
2171 sysctl_fast_gettime(SYSCTL_HANDLER_ARGS)
2172 {
2173 int old_vdso_th_enable, error;
2174
2175 old_vdso_th_enable = vdso_th_enable;
2176 error = sysctl_handle_int(oidp, &old_vdso_th_enable, 0, req);
2177 if (error != 0)
2178 return (error);
2179 vdso_th_enable = old_vdso_th_enable;
2180 return (0);
2181 }
2182 SYSCTL_PROC(_kern_timecounter, OID_AUTO, fast_gettime,
2183 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
2184 NULL, 0, sysctl_fast_gettime, "I", "Enable fast time of day");
2185
2186 uint32_t
2187 tc_fill_vdso_timehands(struct vdso_timehands *vdso_th)
2188 {
2189 struct timehands *th;
2190 uint32_t enabled;
2191
2192 th = timehands;
2193 vdso_th->th_scale = th->th_scale;
2194 vdso_th->th_offset_count = th->th_offset_count;
2195 vdso_th->th_counter_mask = th->th_counter->tc_counter_mask;
2196 vdso_th->th_offset = th->th_offset;
2197 vdso_th->th_boottime = th->th_boottime;
2198 if (th->th_counter->tc_fill_vdso_timehands != NULL) {
2199 enabled = th->th_counter->tc_fill_vdso_timehands(vdso_th,
2200 th->th_counter);
2201 } else
2202 enabled = 0;
2203 if (!vdso_th_enable)
2204 enabled = 0;
2205 return (enabled);
2206 }
2207
2208 #ifdef COMPAT_FREEBSD32
2209 uint32_t
2210 tc_fill_vdso_timehands32(struct vdso_timehands32 *vdso_th32)
2211 {
2212 struct timehands *th;
2213 uint32_t enabled;
2214
2215 th = timehands;
2216 *(uint64_t *)&vdso_th32->th_scale[0] = th->th_scale;
2217 vdso_th32->th_offset_count = th->th_offset_count;
2218 vdso_th32->th_counter_mask = th->th_counter->tc_counter_mask;
2219 vdso_th32->th_offset.sec = th->th_offset.sec;
2220 *(uint64_t *)&vdso_th32->th_offset.frac[0] = th->th_offset.frac;
2221 vdso_th32->th_boottime.sec = th->th_boottime.sec;
2222 *(uint64_t *)&vdso_th32->th_boottime.frac[0] = th->th_boottime.frac;
2223 if (th->th_counter->tc_fill_vdso_timehands32 != NULL) {
2224 enabled = th->th_counter->tc_fill_vdso_timehands32(vdso_th32,
2225 th->th_counter);
2226 } else
2227 enabled = 0;
2228 if (!vdso_th_enable)
2229 enabled = 0;
2230 return (enabled);
2231 }
2232 #endif
2233
2234 #include "opt_ddb.h"
2235 #ifdef DDB
2236 #include <ddb/ddb.h>
2237
2238 DB_SHOW_COMMAND(timecounter, db_show_timecounter)
2239 {
2240 struct timehands *th;
2241 struct timecounter *tc;
2242 u_int val1, val2;
2243
2244 th = timehands;
2245 tc = th->th_counter;
2246 val1 = tc->tc_get_timecount(tc);
2247 __compiler_membar();
2248 val2 = tc->tc_get_timecount(tc);
2249
2250 db_printf("timecounter %p %s\n", tc, tc->tc_name);
2251 db_printf(" mask %#x freq %ju qual %d flags %#x priv %p\n",
2252 tc->tc_counter_mask, (uintmax_t)tc->tc_frequency, tc->tc_quality,
2253 tc->tc_flags, tc->tc_priv);
2254 db_printf(" val %#x %#x\n", val1, val2);
2255 db_printf("timehands adj %#jx scale %#jx ldelta %d off_cnt %d gen %d\n",
2256 (uintmax_t)th->th_adjustment, (uintmax_t)th->th_scale,
2257 th->th_large_delta, th->th_offset_count, th->th_generation);
2258 db_printf(" offset %jd %jd boottime %jd %jd\n",
2259 (intmax_t)th->th_offset.sec, (uintmax_t)th->th_offset.frac,
2260 (intmax_t)th->th_boottime.sec, (uintmax_t)th->th_boottime.frac);
2261 }
2262 #endif
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