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