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