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