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 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
16 #include <sys/cdefs.h>
17 __FBSDID("$FreeBSD: releng/11.0/sys/kern/kern_tc.c 298819 2016-04-29 22:15:33Z pfg $");
18
19 #include "opt_compat.h"
20 #include "opt_ntp.h"
21 #include "opt_ffclock.h"
22
23 #include <sys/param.h>
24 #include <sys/kernel.h>
25 #include <sys/limits.h>
26 #include <sys/lock.h>
27 #include <sys/mutex.h>
28 #include <sys/sbuf.h>
29 #include <sys/sysctl.h>
30 #include <sys/syslog.h>
31 #include <sys/systm.h>
32 #include <sys/timeffc.h>
33 #include <sys/timepps.h>
34 #include <sys/timetc.h>
35 #include <sys/timex.h>
36 #include <sys/vdso.h>
37
38 /*
39 * A large step happens on boot. This constant detects such steps.
40 * It is relatively small so that ntp_update_second gets called enough
41 * in the typical 'missed a couple of seconds' case, but doesn't loop
42 * forever when the time step is large.
43 */
44 #define LARGE_STEP 200
45
46 /*
47 * Implement a dummy timecounter which we can use until we get a real one
48 * in the air. This allows the console and other early stuff to use
49 * time services.
50 */
51
52 static u_int
53 dummy_get_timecount(struct timecounter *tc)
54 {
55 static u_int now;
56
57 return (++now);
58 }
59
60 static struct timecounter dummy_timecounter = {
61 dummy_get_timecount, 0, ~0u, 1000000, "dummy", -1000000
62 };
63
64 struct timehands {
65 /* These fields must be initialized by the driver. */
66 struct timecounter *th_counter;
67 int64_t th_adjustment;
68 uint64_t th_scale;
69 u_int th_offset_count;
70 struct bintime th_offset;
71 struct timeval th_microtime;
72 struct timespec th_nanotime;
73 /* Fields not to be copied in tc_windup start with th_generation. */
74 u_int th_generation;
75 struct timehands *th_next;
76 };
77
78 static struct timehands th0;
79 static struct timehands th9 = { NULL, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th0};
80 static struct timehands th8 = { NULL, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th9};
81 static struct timehands th7 = { NULL, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th8};
82 static struct timehands th6 = { NULL, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th7};
83 static struct timehands th5 = { NULL, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th6};
84 static struct timehands th4 = { NULL, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th5};
85 static struct timehands th3 = { NULL, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th4};
86 static struct timehands th2 = { NULL, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th3};
87 static struct timehands th1 = { NULL, 0, 0, 0, {0, 0}, {0, 0}, {0, 0}, 0, &th2};
88 static struct timehands th0 = {
89 &dummy_timecounter,
90 0,
91 (uint64_t)-1 / 1000000,
92 0,
93 {1, 0},
94 {0, 0},
95 {0, 0},
96 1,
97 &th1
98 };
99
100 static struct timehands *volatile timehands = &th0;
101 struct timecounter *timecounter = &dummy_timecounter;
102 static struct timecounter *timecounters = &dummy_timecounter;
103
104 int tc_min_ticktock_freq = 1;
105
106 volatile time_t time_second = 1;
107 volatile time_t time_uptime = 1;
108
109 struct bintime boottimebin;
110 struct timeval boottime;
111 static int sysctl_kern_boottime(SYSCTL_HANDLER_ARGS);
112 SYSCTL_PROC(_kern, KERN_BOOTTIME, boottime, CTLTYPE_STRUCT|CTLFLAG_RD,
113 NULL, 0, sysctl_kern_boottime, "S,timeval", "System boottime");
114
115 SYSCTL_NODE(_kern, OID_AUTO, timecounter, CTLFLAG_RW, 0, "");
116 static SYSCTL_NODE(_kern_timecounter, OID_AUTO, tc, CTLFLAG_RW, 0, "");
117
118 static int timestepwarnings;
119 SYSCTL_INT(_kern_timecounter, OID_AUTO, stepwarnings, CTLFLAG_RW,
120 ×tepwarnings, 0, "Log time steps");
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 static int tc_chosen; /* Non-zero if a specific tc was chosen via sysctl. */
137
138 static void tc_windup(void);
139 static void cpu_tick_calibrate(int);
140
141 void dtrace_getnanotime(struct timespec *tsp);
142
143 static int
144 sysctl_kern_boottime(SYSCTL_HANDLER_ARGS)
145 {
146 #ifndef __mips__
147 #ifdef SCTL_MASK32
148 int tv[2];
149
150 if (req->flags & SCTL_MASK32) {
151 tv[0] = boottime.tv_sec;
152 tv[1] = boottime.tv_usec;
153 return SYSCTL_OUT(req, tv, sizeof(tv));
154 } else
155 #endif
156 #endif
157 return SYSCTL_OUT(req, &boottime, sizeof(boottime));
158 }
159
160 static int
161 sysctl_kern_timecounter_get(SYSCTL_HANDLER_ARGS)
162 {
163 u_int ncount;
164 struct timecounter *tc = arg1;
165
166 ncount = tc->tc_get_timecount(tc);
167 return sysctl_handle_int(oidp, &ncount, 0, req);
168 }
169
170 static int
171 sysctl_kern_timecounter_freq(SYSCTL_HANDLER_ARGS)
172 {
173 uint64_t freq;
174 struct timecounter *tc = arg1;
175
176 freq = tc->tc_frequency;
177 return sysctl_handle_64(oidp, &freq, 0, req);
178 }
179
180 /*
181 * Return the difference between the timehands' counter value now and what
182 * was when we copied it to the timehands' offset_count.
183 */
184 static __inline u_int
185 tc_delta(struct timehands *th)
186 {
187 struct timecounter *tc;
188
189 tc = th->th_counter;
190 return ((tc->tc_get_timecount(tc) - th->th_offset_count) &
191 tc->tc_counter_mask);
192 }
193
194 /*
195 * Functions for reading the time. We have to loop until we are sure that
196 * the timehands that we operated on was not updated under our feet. See
197 * the comment in <sys/time.h> for a description of these 12 functions.
198 */
199
200 #ifdef FFCLOCK
201 void
202 fbclock_binuptime(struct bintime *bt)
203 {
204 struct timehands *th;
205 unsigned int gen;
206
207 do {
208 th = timehands;
209 gen = atomic_load_acq_int(&th->th_generation);
210 *bt = th->th_offset;
211 bintime_addx(bt, th->th_scale * tc_delta(th));
212 atomic_thread_fence_acq();
213 } while (gen == 0 || gen != th->th_generation);
214 }
215
216 void
217 fbclock_nanouptime(struct timespec *tsp)
218 {
219 struct bintime bt;
220
221 fbclock_binuptime(&bt);
222 bintime2timespec(&bt, tsp);
223 }
224
225 void
226 fbclock_microuptime(struct timeval *tvp)
227 {
228 struct bintime bt;
229
230 fbclock_binuptime(&bt);
231 bintime2timeval(&bt, tvp);
232 }
233
234 void
235 fbclock_bintime(struct bintime *bt)
236 {
237
238 fbclock_binuptime(bt);
239 bintime_add(bt, &boottimebin);
240 }
241
242 void
243 fbclock_nanotime(struct timespec *tsp)
244 {
245 struct bintime bt;
246
247 fbclock_bintime(&bt);
248 bintime2timespec(&bt, tsp);
249 }
250
251 void
252 fbclock_microtime(struct timeval *tvp)
253 {
254 struct bintime bt;
255
256 fbclock_bintime(&bt);
257 bintime2timeval(&bt, tvp);
258 }
259
260 void
261 fbclock_getbinuptime(struct bintime *bt)
262 {
263 struct timehands *th;
264 unsigned int gen;
265
266 do {
267 th = timehands;
268 gen = atomic_load_acq_int(&th->th_generation);
269 *bt = th->th_offset;
270 atomic_thread_fence_acq();
271 } while (gen == 0 || gen != th->th_generation);
272 }
273
274 void
275 fbclock_getnanouptime(struct timespec *tsp)
276 {
277 struct timehands *th;
278 unsigned int gen;
279
280 do {
281 th = timehands;
282 gen = atomic_load_acq_int(&th->th_generation);
283 bintime2timespec(&th->th_offset, tsp);
284 atomic_thread_fence_acq();
285 } while (gen == 0 || gen != th->th_generation);
286 }
287
288 void
289 fbclock_getmicrouptime(struct timeval *tvp)
290 {
291 struct timehands *th;
292 unsigned int gen;
293
294 do {
295 th = timehands;
296 gen = atomic_load_acq_int(&th->th_generation);
297 bintime2timeval(&th->th_offset, tvp);
298 atomic_thread_fence_acq();
299 } while (gen == 0 || gen != th->th_generation);
300 }
301
302 void
303 fbclock_getbintime(struct bintime *bt)
304 {
305 struct timehands *th;
306 unsigned int gen;
307
308 do {
309 th = timehands;
310 gen = atomic_load_acq_int(&th->th_generation);
311 *bt = th->th_offset;
312 atomic_thread_fence_acq();
313 } while (gen == 0 || gen != th->th_generation);
314 bintime_add(bt, &boottimebin);
315 }
316
317 void
318 fbclock_getnanotime(struct timespec *tsp)
319 {
320 struct timehands *th;
321 unsigned int gen;
322
323 do {
324 th = timehands;
325 gen = atomic_load_acq_int(&th->th_generation);
326 *tsp = th->th_nanotime;
327 atomic_thread_fence_acq();
328 } while (gen == 0 || gen != th->th_generation);
329 }
330
331 void
332 fbclock_getmicrotime(struct timeval *tvp)
333 {
334 struct timehands *th;
335 unsigned int gen;
336
337 do {
338 th = timehands;
339 gen = atomic_load_acq_int(&th->th_generation);
340 *tvp = th->th_microtime;
341 atomic_thread_fence_acq();
342 } while (gen == 0 || gen != th->th_generation);
343 }
344 #else /* !FFCLOCK */
345 void
346 binuptime(struct bintime *bt)
347 {
348 struct timehands *th;
349 u_int gen;
350
351 do {
352 th = timehands;
353 gen = atomic_load_acq_int(&th->th_generation);
354 *bt = th->th_offset;
355 bintime_addx(bt, th->th_scale * tc_delta(th));
356 atomic_thread_fence_acq();
357 } while (gen == 0 || gen != th->th_generation);
358 }
359
360 void
361 nanouptime(struct timespec *tsp)
362 {
363 struct bintime bt;
364
365 binuptime(&bt);
366 bintime2timespec(&bt, tsp);
367 }
368
369 void
370 microuptime(struct timeval *tvp)
371 {
372 struct bintime bt;
373
374 binuptime(&bt);
375 bintime2timeval(&bt, tvp);
376 }
377
378 void
379 bintime(struct bintime *bt)
380 {
381
382 binuptime(bt);
383 bintime_add(bt, &boottimebin);
384 }
385
386 void
387 nanotime(struct timespec *tsp)
388 {
389 struct bintime bt;
390
391 bintime(&bt);
392 bintime2timespec(&bt, tsp);
393 }
394
395 void
396 microtime(struct timeval *tvp)
397 {
398 struct bintime bt;
399
400 bintime(&bt);
401 bintime2timeval(&bt, tvp);
402 }
403
404 void
405 getbinuptime(struct bintime *bt)
406 {
407 struct timehands *th;
408 u_int gen;
409
410 do {
411 th = timehands;
412 gen = atomic_load_acq_int(&th->th_generation);
413 *bt = th->th_offset;
414 atomic_thread_fence_acq();
415 } while (gen == 0 || gen != th->th_generation);
416 }
417
418 void
419 getnanouptime(struct timespec *tsp)
420 {
421 struct timehands *th;
422 u_int gen;
423
424 do {
425 th = timehands;
426 gen = atomic_load_acq_int(&th->th_generation);
427 bintime2timespec(&th->th_offset, tsp);
428 atomic_thread_fence_acq();
429 } while (gen == 0 || gen != th->th_generation);
430 }
431
432 void
433 getmicrouptime(struct timeval *tvp)
434 {
435 struct timehands *th;
436 u_int gen;
437
438 do {
439 th = timehands;
440 gen = atomic_load_acq_int(&th->th_generation);
441 bintime2timeval(&th->th_offset, tvp);
442 atomic_thread_fence_acq();
443 } while (gen == 0 || gen != th->th_generation);
444 }
445
446 void
447 getbintime(struct bintime *bt)
448 {
449 struct timehands *th;
450 u_int gen;
451
452 do {
453 th = timehands;
454 gen = atomic_load_acq_int(&th->th_generation);
455 *bt = th->th_offset;
456 atomic_thread_fence_acq();
457 } while (gen == 0 || gen != th->th_generation);
458 bintime_add(bt, &boottimebin);
459 }
460
461 void
462 getnanotime(struct timespec *tsp)
463 {
464 struct timehands *th;
465 u_int gen;
466
467 do {
468 th = timehands;
469 gen = atomic_load_acq_int(&th->th_generation);
470 *tsp = th->th_nanotime;
471 atomic_thread_fence_acq();
472 } while (gen == 0 || gen != th->th_generation);
473 }
474
475 void
476 getmicrotime(struct timeval *tvp)
477 {
478 struct timehands *th;
479 u_int gen;
480
481 do {
482 th = timehands;
483 gen = atomic_load_acq_int(&th->th_generation);
484 *tvp = th->th_microtime;
485 atomic_thread_fence_acq();
486 } while (gen == 0 || gen != th->th_generation);
487 }
488 #endif /* FFCLOCK */
489
490 #ifdef FFCLOCK
491 /*
492 * Support for feed-forward synchronization algorithms. This is heavily inspired
493 * by the timehands mechanism but kept independent from it. *_windup() functions
494 * have some connection to avoid accessing the timecounter hardware more than
495 * necessary.
496 */
497
498 /* Feed-forward clock estimates kept updated by the synchronization daemon. */
499 struct ffclock_estimate ffclock_estimate;
500 struct bintime ffclock_boottime; /* Feed-forward boot time estimate. */
501 uint32_t ffclock_status; /* Feed-forward clock status. */
502 int8_t ffclock_updated; /* New estimates are available. */
503 struct mtx ffclock_mtx; /* Mutex on ffclock_estimate. */
504
505 struct fftimehands {
506 struct ffclock_estimate cest;
507 struct bintime tick_time;
508 struct bintime tick_time_lerp;
509 ffcounter tick_ffcount;
510 uint64_t period_lerp;
511 volatile uint8_t gen;
512 struct fftimehands *next;
513 };
514
515 #define NUM_ELEMENTS(x) (sizeof(x) / sizeof(*x))
516
517 static struct fftimehands ffth[10];
518 static struct fftimehands *volatile fftimehands = ffth;
519
520 static void
521 ffclock_init(void)
522 {
523 struct fftimehands *cur;
524 struct fftimehands *last;
525
526 memset(ffth, 0, sizeof(ffth));
527
528 last = ffth + NUM_ELEMENTS(ffth) - 1;
529 for (cur = ffth; cur < last; cur++)
530 cur->next = cur + 1;
531 last->next = ffth;
532
533 ffclock_updated = 0;
534 ffclock_status = FFCLOCK_STA_UNSYNC;
535 mtx_init(&ffclock_mtx, "ffclock lock", NULL, MTX_DEF);
536 }
537
538 /*
539 * Reset the feed-forward clock estimates. Called from inittodr() to get things
540 * kick started and uses the timecounter nominal frequency as a first period
541 * estimate. Note: this function may be called several time just after boot.
542 * Note: this is the only function that sets the value of boot time for the
543 * monotonic (i.e. uptime) version of the feed-forward clock.
544 */
545 void
546 ffclock_reset_clock(struct timespec *ts)
547 {
548 struct timecounter *tc;
549 struct ffclock_estimate cest;
550
551 tc = timehands->th_counter;
552 memset(&cest, 0, sizeof(struct ffclock_estimate));
553
554 timespec2bintime(ts, &ffclock_boottime);
555 timespec2bintime(ts, &(cest.update_time));
556 ffclock_read_counter(&cest.update_ffcount);
557 cest.leapsec_next = 0;
558 cest.period = ((1ULL << 63) / tc->tc_frequency) << 1;
559 cest.errb_abs = 0;
560 cest.errb_rate = 0;
561 cest.status = FFCLOCK_STA_UNSYNC;
562 cest.leapsec_total = 0;
563 cest.leapsec = 0;
564
565 mtx_lock(&ffclock_mtx);
566 bcopy(&cest, &ffclock_estimate, sizeof(struct ffclock_estimate));
567 ffclock_updated = INT8_MAX;
568 mtx_unlock(&ffclock_mtx);
569
570 printf("ffclock reset: %s (%llu Hz), time = %ld.%09lu\n", tc->tc_name,
571 (unsigned long long)tc->tc_frequency, (long)ts->tv_sec,
572 (unsigned long)ts->tv_nsec);
573 }
574
575 /*
576 * Sub-routine to convert a time interval measured in RAW counter units to time
577 * in seconds stored in bintime format.
578 * NOTE: bintime_mul requires u_int, but the value of the ffcounter may be
579 * larger than the max value of u_int (on 32 bit architecture). Loop to consume
580 * extra cycles.
581 */
582 static void
583 ffclock_convert_delta(ffcounter ffdelta, uint64_t period, struct bintime *bt)
584 {
585 struct bintime bt2;
586 ffcounter delta, delta_max;
587
588 delta_max = (1ULL << (8 * sizeof(unsigned int))) - 1;
589 bintime_clear(bt);
590 do {
591 if (ffdelta > delta_max)
592 delta = delta_max;
593 else
594 delta = ffdelta;
595 bt2.sec = 0;
596 bt2.frac = period;
597 bintime_mul(&bt2, (unsigned int)delta);
598 bintime_add(bt, &bt2);
599 ffdelta -= delta;
600 } while (ffdelta > 0);
601 }
602
603 /*
604 * Update the fftimehands.
605 * Push the tick ffcount and time(s) forward based on current clock estimate.
606 * The conversion from ffcounter to bintime relies on the difference clock
607 * principle, whose accuracy relies on computing small time intervals. If a new
608 * clock estimate has been passed by the synchronisation daemon, make it
609 * current, and compute the linear interpolation for monotonic time if needed.
610 */
611 static void
612 ffclock_windup(unsigned int delta)
613 {
614 struct ffclock_estimate *cest;
615 struct fftimehands *ffth;
616 struct bintime bt, gap_lerp;
617 ffcounter ffdelta;
618 uint64_t frac;
619 unsigned int polling;
620 uint8_t forward_jump, ogen;
621
622 /*
623 * Pick the next timehand, copy current ffclock estimates and move tick
624 * times and counter forward.
625 */
626 forward_jump = 0;
627 ffth = fftimehands->next;
628 ogen = ffth->gen;
629 ffth->gen = 0;
630 cest = &ffth->cest;
631 bcopy(&fftimehands->cest, cest, sizeof(struct ffclock_estimate));
632 ffdelta = (ffcounter)delta;
633 ffth->period_lerp = fftimehands->period_lerp;
634
635 ffth->tick_time = fftimehands->tick_time;
636 ffclock_convert_delta(ffdelta, cest->period, &bt);
637 bintime_add(&ffth->tick_time, &bt);
638
639 ffth->tick_time_lerp = fftimehands->tick_time_lerp;
640 ffclock_convert_delta(ffdelta, ffth->period_lerp, &bt);
641 bintime_add(&ffth->tick_time_lerp, &bt);
642
643 ffth->tick_ffcount = fftimehands->tick_ffcount + ffdelta;
644
645 /*
646 * Assess the status of the clock, if the last update is too old, it is
647 * likely the synchronisation daemon is dead and the clock is free
648 * running.
649 */
650 if (ffclock_updated == 0) {
651 ffdelta = ffth->tick_ffcount - cest->update_ffcount;
652 ffclock_convert_delta(ffdelta, cest->period, &bt);
653 if (bt.sec > 2 * FFCLOCK_SKM_SCALE)
654 ffclock_status |= FFCLOCK_STA_UNSYNC;
655 }
656
657 /*
658 * If available, grab updated clock estimates and make them current.
659 * Recompute time at this tick using the updated estimates. The clock
660 * estimates passed the feed-forward synchronisation daemon may result
661 * in time conversion that is not monotonically increasing (just after
662 * the update). time_lerp is a particular linear interpolation over the
663 * synchronisation algo polling period that ensures monotonicity for the
664 * clock ids requesting it.
665 */
666 if (ffclock_updated > 0) {
667 bcopy(&ffclock_estimate, cest, sizeof(struct ffclock_estimate));
668 ffdelta = ffth->tick_ffcount - cest->update_ffcount;
669 ffth->tick_time = cest->update_time;
670 ffclock_convert_delta(ffdelta, cest->period, &bt);
671 bintime_add(&ffth->tick_time, &bt);
672
673 /* ffclock_reset sets ffclock_updated to INT8_MAX */
674 if (ffclock_updated == INT8_MAX)
675 ffth->tick_time_lerp = ffth->tick_time;
676
677 if (bintime_cmp(&ffth->tick_time, &ffth->tick_time_lerp, >))
678 forward_jump = 1;
679 else
680 forward_jump = 0;
681
682 bintime_clear(&gap_lerp);
683 if (forward_jump) {
684 gap_lerp = ffth->tick_time;
685 bintime_sub(&gap_lerp, &ffth->tick_time_lerp);
686 } else {
687 gap_lerp = ffth->tick_time_lerp;
688 bintime_sub(&gap_lerp, &ffth->tick_time);
689 }
690
691 /*
692 * The reset from the RTC clock may be far from accurate, and
693 * reducing the gap between real time and interpolated time
694 * could take a very long time if the interpolated clock insists
695 * on strict monotonicity. The clock is reset under very strict
696 * conditions (kernel time is known to be wrong and
697 * synchronization daemon has been restarted recently.
698 * ffclock_boottime absorbs the jump to ensure boot time is
699 * correct and uptime functions stay consistent.
700 */
701 if (((ffclock_status & FFCLOCK_STA_UNSYNC) == FFCLOCK_STA_UNSYNC) &&
702 ((cest->status & FFCLOCK_STA_UNSYNC) == 0) &&
703 ((cest->status & FFCLOCK_STA_WARMUP) == FFCLOCK_STA_WARMUP)) {
704 if (forward_jump)
705 bintime_add(&ffclock_boottime, &gap_lerp);
706 else
707 bintime_sub(&ffclock_boottime, &gap_lerp);
708 ffth->tick_time_lerp = ffth->tick_time;
709 bintime_clear(&gap_lerp);
710 }
711
712 ffclock_status = cest->status;
713 ffth->period_lerp = cest->period;
714
715 /*
716 * Compute corrected period used for the linear interpolation of
717 * time. The rate of linear interpolation is capped to 5000PPM
718 * (5ms/s).
719 */
720 if (bintime_isset(&gap_lerp)) {
721 ffdelta = cest->update_ffcount;
722 ffdelta -= fftimehands->cest.update_ffcount;
723 ffclock_convert_delta(ffdelta, cest->period, &bt);
724 polling = bt.sec;
725 bt.sec = 0;
726 bt.frac = 5000000 * (uint64_t)18446744073LL;
727 bintime_mul(&bt, polling);
728 if (bintime_cmp(&gap_lerp, &bt, >))
729 gap_lerp = bt;
730
731 /* Approximate 1 sec by 1-(1/2^64) to ease arithmetic */
732 frac = 0;
733 if (gap_lerp.sec > 0) {
734 frac -= 1;
735 frac /= ffdelta / gap_lerp.sec;
736 }
737 frac += gap_lerp.frac / ffdelta;
738
739 if (forward_jump)
740 ffth->period_lerp += frac;
741 else
742 ffth->period_lerp -= frac;
743 }
744
745 ffclock_updated = 0;
746 }
747 if (++ogen == 0)
748 ogen = 1;
749 ffth->gen = ogen;
750 fftimehands = ffth;
751 }
752
753 /*
754 * Adjust the fftimehands when the timecounter is changed. Stating the obvious,
755 * the old and new hardware counter cannot be read simultaneously. tc_windup()
756 * does read the two counters 'back to back', but a few cycles are effectively
757 * lost, and not accumulated in tick_ffcount. This is a fairly radical
758 * operation for a feed-forward synchronization daemon, and it is its job to not
759 * pushing irrelevant data to the kernel. Because there is no locking here,
760 * simply force to ignore pending or next update to give daemon a chance to
761 * realize the counter has changed.
762 */
763 static void
764 ffclock_change_tc(struct timehands *th)
765 {
766 struct fftimehands *ffth;
767 struct ffclock_estimate *cest;
768 struct timecounter *tc;
769 uint8_t ogen;
770
771 tc = th->th_counter;
772 ffth = fftimehands->next;
773 ogen = ffth->gen;
774 ffth->gen = 0;
775
776 cest = &ffth->cest;
777 bcopy(&(fftimehands->cest), cest, sizeof(struct ffclock_estimate));
778 cest->period = ((1ULL << 63) / tc->tc_frequency ) << 1;
779 cest->errb_abs = 0;
780 cest->errb_rate = 0;
781 cest->status |= FFCLOCK_STA_UNSYNC;
782
783 ffth->tick_ffcount = fftimehands->tick_ffcount;
784 ffth->tick_time_lerp = fftimehands->tick_time_lerp;
785 ffth->tick_time = fftimehands->tick_time;
786 ffth->period_lerp = cest->period;
787
788 /* Do not lock but ignore next update from synchronization daemon. */
789 ffclock_updated--;
790
791 if (++ogen == 0)
792 ogen = 1;
793 ffth->gen = ogen;
794 fftimehands = ffth;
795 }
796
797 /*
798 * Retrieve feed-forward counter and time of last kernel tick.
799 */
800 void
801 ffclock_last_tick(ffcounter *ffcount, struct bintime *bt, uint32_t flags)
802 {
803 struct fftimehands *ffth;
804 uint8_t gen;
805
806 /*
807 * No locking but check generation has not changed. Also need to make
808 * sure ffdelta is positive, i.e. ffcount > tick_ffcount.
809 */
810 do {
811 ffth = fftimehands;
812 gen = ffth->gen;
813 if ((flags & FFCLOCK_LERP) == FFCLOCK_LERP)
814 *bt = ffth->tick_time_lerp;
815 else
816 *bt = ffth->tick_time;
817 *ffcount = ffth->tick_ffcount;
818 } while (gen == 0 || gen != ffth->gen);
819 }
820
821 /*
822 * Absolute clock conversion. Low level function to convert ffcounter to
823 * bintime. The ffcounter is converted using the current ffclock period estimate
824 * or the "interpolated period" to ensure monotonicity.
825 * NOTE: this conversion may have been deferred, and the clock updated since the
826 * hardware counter has been read.
827 */
828 void
829 ffclock_convert_abs(ffcounter ffcount, struct bintime *bt, uint32_t flags)
830 {
831 struct fftimehands *ffth;
832 struct bintime bt2;
833 ffcounter ffdelta;
834 uint8_t gen;
835
836 /*
837 * No locking but check generation has not changed. Also need to make
838 * sure ffdelta is positive, i.e. ffcount > tick_ffcount.
839 */
840 do {
841 ffth = fftimehands;
842 gen = ffth->gen;
843 if (ffcount > ffth->tick_ffcount)
844 ffdelta = ffcount - ffth->tick_ffcount;
845 else
846 ffdelta = ffth->tick_ffcount - ffcount;
847
848 if ((flags & FFCLOCK_LERP) == FFCLOCK_LERP) {
849 *bt = ffth->tick_time_lerp;
850 ffclock_convert_delta(ffdelta, ffth->period_lerp, &bt2);
851 } else {
852 *bt = ffth->tick_time;
853 ffclock_convert_delta(ffdelta, ffth->cest.period, &bt2);
854 }
855
856 if (ffcount > ffth->tick_ffcount)
857 bintime_add(bt, &bt2);
858 else
859 bintime_sub(bt, &bt2);
860 } while (gen == 0 || gen != ffth->gen);
861 }
862
863 /*
864 * Difference clock conversion.
865 * Low level function to Convert a time interval measured in RAW counter units
866 * into bintime. The difference clock allows measuring small intervals much more
867 * reliably than the absolute clock.
868 */
869 void
870 ffclock_convert_diff(ffcounter ffdelta, struct bintime *bt)
871 {
872 struct fftimehands *ffth;
873 uint8_t gen;
874
875 /* No locking but check generation has not changed. */
876 do {
877 ffth = fftimehands;
878 gen = ffth->gen;
879 ffclock_convert_delta(ffdelta, ffth->cest.period, bt);
880 } while (gen == 0 || gen != ffth->gen);
881 }
882
883 /*
884 * Access to current ffcounter value.
885 */
886 void
887 ffclock_read_counter(ffcounter *ffcount)
888 {
889 struct timehands *th;
890 struct fftimehands *ffth;
891 unsigned int gen, delta;
892
893 /*
894 * ffclock_windup() called from tc_windup(), safe to rely on
895 * th->th_generation only, for correct delta and ffcounter.
896 */
897 do {
898 th = timehands;
899 gen = atomic_load_acq_int(&th->th_generation);
900 ffth = fftimehands;
901 delta = tc_delta(th);
902 *ffcount = ffth->tick_ffcount;
903 atomic_thread_fence_acq();
904 } while (gen == 0 || gen != th->th_generation);
905
906 *ffcount += delta;
907 }
908
909 void
910 binuptime(struct bintime *bt)
911 {
912
913 binuptime_fromclock(bt, sysclock_active);
914 }
915
916 void
917 nanouptime(struct timespec *tsp)
918 {
919
920 nanouptime_fromclock(tsp, sysclock_active);
921 }
922
923 void
924 microuptime(struct timeval *tvp)
925 {
926
927 microuptime_fromclock(tvp, sysclock_active);
928 }
929
930 void
931 bintime(struct bintime *bt)
932 {
933
934 bintime_fromclock(bt, sysclock_active);
935 }
936
937 void
938 nanotime(struct timespec *tsp)
939 {
940
941 nanotime_fromclock(tsp, sysclock_active);
942 }
943
944 void
945 microtime(struct timeval *tvp)
946 {
947
948 microtime_fromclock(tvp, sysclock_active);
949 }
950
951 void
952 getbinuptime(struct bintime *bt)
953 {
954
955 getbinuptime_fromclock(bt, sysclock_active);
956 }
957
958 void
959 getnanouptime(struct timespec *tsp)
960 {
961
962 getnanouptime_fromclock(tsp, sysclock_active);
963 }
964
965 void
966 getmicrouptime(struct timeval *tvp)
967 {
968
969 getmicrouptime_fromclock(tvp, sysclock_active);
970 }
971
972 void
973 getbintime(struct bintime *bt)
974 {
975
976 getbintime_fromclock(bt, sysclock_active);
977 }
978
979 void
980 getnanotime(struct timespec *tsp)
981 {
982
983 getnanotime_fromclock(tsp, sysclock_active);
984 }
985
986 void
987 getmicrotime(struct timeval *tvp)
988 {
989
990 getmicrouptime_fromclock(tvp, sysclock_active);
991 }
992
993 #endif /* FFCLOCK */
994
995 /*
996 * This is a clone of getnanotime and used for walltimestamps.
997 * The dtrace_ prefix prevents fbt from creating probes for
998 * it so walltimestamp can be safely used in all fbt probes.
999 */
1000 void
1001 dtrace_getnanotime(struct timespec *tsp)
1002 {
1003 struct timehands *th;
1004 u_int gen;
1005
1006 do {
1007 th = timehands;
1008 gen = atomic_load_acq_int(&th->th_generation);
1009 *tsp = th->th_nanotime;
1010 atomic_thread_fence_acq();
1011 } while (gen == 0 || gen != th->th_generation);
1012 }
1013
1014 /*
1015 * System clock currently providing time to the system. Modifiable via sysctl
1016 * when the FFCLOCK option is defined.
1017 */
1018 int sysclock_active = SYSCLOCK_FBCK;
1019
1020 /* Internal NTP status and error estimates. */
1021 extern int time_status;
1022 extern long time_esterror;
1023
1024 /*
1025 * Take a snapshot of sysclock data which can be used to compare system clocks
1026 * and generate timestamps after the fact.
1027 */
1028 void
1029 sysclock_getsnapshot(struct sysclock_snap *clock_snap, int fast)
1030 {
1031 struct fbclock_info *fbi;
1032 struct timehands *th;
1033 struct bintime bt;
1034 unsigned int delta, gen;
1035 #ifdef FFCLOCK
1036 ffcounter ffcount;
1037 struct fftimehands *ffth;
1038 struct ffclock_info *ffi;
1039 struct ffclock_estimate cest;
1040
1041 ffi = &clock_snap->ff_info;
1042 #endif
1043
1044 fbi = &clock_snap->fb_info;
1045 delta = 0;
1046
1047 do {
1048 th = timehands;
1049 gen = atomic_load_acq_int(&th->th_generation);
1050 fbi->th_scale = th->th_scale;
1051 fbi->tick_time = th->th_offset;
1052 #ifdef FFCLOCK
1053 ffth = fftimehands;
1054 ffi->tick_time = ffth->tick_time_lerp;
1055 ffi->tick_time_lerp = ffth->tick_time_lerp;
1056 ffi->period = ffth->cest.period;
1057 ffi->period_lerp = ffth->period_lerp;
1058 clock_snap->ffcount = ffth->tick_ffcount;
1059 cest = ffth->cest;
1060 #endif
1061 if (!fast)
1062 delta = tc_delta(th);
1063 atomic_thread_fence_acq();
1064 } while (gen == 0 || gen != th->th_generation);
1065
1066 clock_snap->delta = delta;
1067 clock_snap->sysclock_active = sysclock_active;
1068
1069 /* Record feedback clock status and error. */
1070 clock_snap->fb_info.status = time_status;
1071 /* XXX: Very crude estimate of feedback clock error. */
1072 bt.sec = time_esterror / 1000000;
1073 bt.frac = ((time_esterror - bt.sec) * 1000000) *
1074 (uint64_t)18446744073709ULL;
1075 clock_snap->fb_info.error = bt;
1076
1077 #ifdef FFCLOCK
1078 if (!fast)
1079 clock_snap->ffcount += delta;
1080
1081 /* Record feed-forward clock leap second adjustment. */
1082 ffi->leapsec_adjustment = cest.leapsec_total;
1083 if (clock_snap->ffcount > cest.leapsec_next)
1084 ffi->leapsec_adjustment -= cest.leapsec;
1085
1086 /* Record feed-forward clock status and error. */
1087 clock_snap->ff_info.status = cest.status;
1088 ffcount = clock_snap->ffcount - cest.update_ffcount;
1089 ffclock_convert_delta(ffcount, cest.period, &bt);
1090 /* 18446744073709 = int(2^64/1e12), err_bound_rate in [ps/s]. */
1091 bintime_mul(&bt, cest.errb_rate * (uint64_t)18446744073709ULL);
1092 /* 18446744073 = int(2^64 / 1e9), since err_abs in [ns]. */
1093 bintime_addx(&bt, cest.errb_abs * (uint64_t)18446744073ULL);
1094 clock_snap->ff_info.error = bt;
1095 #endif
1096 }
1097
1098 /*
1099 * Convert a sysclock snapshot into a struct bintime based on the specified
1100 * clock source and flags.
1101 */
1102 int
1103 sysclock_snap2bintime(struct sysclock_snap *cs, struct bintime *bt,
1104 int whichclock, uint32_t flags)
1105 {
1106 #ifdef FFCLOCK
1107 struct bintime bt2;
1108 uint64_t period;
1109 #endif
1110
1111 switch (whichclock) {
1112 case SYSCLOCK_FBCK:
1113 *bt = cs->fb_info.tick_time;
1114
1115 /* If snapshot was created with !fast, delta will be >0. */
1116 if (cs->delta > 0)
1117 bintime_addx(bt, cs->fb_info.th_scale * cs->delta);
1118
1119 if ((flags & FBCLOCK_UPTIME) == 0)
1120 bintime_add(bt, &boottimebin);
1121 break;
1122 #ifdef FFCLOCK
1123 case SYSCLOCK_FFWD:
1124 if (flags & FFCLOCK_LERP) {
1125 *bt = cs->ff_info.tick_time_lerp;
1126 period = cs->ff_info.period_lerp;
1127 } else {
1128 *bt = cs->ff_info.tick_time;
1129 period = cs->ff_info.period;
1130 }
1131
1132 /* If snapshot was created with !fast, delta will be >0. */
1133 if (cs->delta > 0) {
1134 ffclock_convert_delta(cs->delta, period, &bt2);
1135 bintime_add(bt, &bt2);
1136 }
1137
1138 /* Leap second adjustment. */
1139 if (flags & FFCLOCK_LEAPSEC)
1140 bt->sec -= cs->ff_info.leapsec_adjustment;
1141
1142 /* Boot time adjustment, for uptime/monotonic clocks. */
1143 if (flags & FFCLOCK_UPTIME)
1144 bintime_sub(bt, &ffclock_boottime);
1145 break;
1146 #endif
1147 default:
1148 return (EINVAL);
1149 break;
1150 }
1151
1152 return (0);
1153 }
1154
1155 /*
1156 * Initialize a new timecounter and possibly use it.
1157 */
1158 void
1159 tc_init(struct timecounter *tc)
1160 {
1161 u_int u;
1162 struct sysctl_oid *tc_root;
1163
1164 u = tc->tc_frequency / tc->tc_counter_mask;
1165 /* XXX: We need some margin here, 10% is a guess */
1166 u *= 11;
1167 u /= 10;
1168 if (u > hz && tc->tc_quality >= 0) {
1169 tc->tc_quality = -2000;
1170 if (bootverbose) {
1171 printf("Timecounter \"%s\" frequency %ju Hz",
1172 tc->tc_name, (uintmax_t)tc->tc_frequency);
1173 printf(" -- Insufficient hz, needs at least %u\n", u);
1174 }
1175 } else if (tc->tc_quality >= 0 || bootverbose) {
1176 printf("Timecounter \"%s\" frequency %ju Hz quality %d\n",
1177 tc->tc_name, (uintmax_t)tc->tc_frequency,
1178 tc->tc_quality);
1179 }
1180
1181 tc->tc_next = timecounters;
1182 timecounters = tc;
1183 /*
1184 * Set up sysctl tree for this counter.
1185 */
1186 tc_root = SYSCTL_ADD_NODE(NULL,
1187 SYSCTL_STATIC_CHILDREN(_kern_timecounter_tc), OID_AUTO, tc->tc_name,
1188 CTLFLAG_RW, 0, "timecounter description");
1189 SYSCTL_ADD_UINT(NULL, SYSCTL_CHILDREN(tc_root), OID_AUTO,
1190 "mask", CTLFLAG_RD, &(tc->tc_counter_mask), 0,
1191 "mask for implemented bits");
1192 SYSCTL_ADD_PROC(NULL, SYSCTL_CHILDREN(tc_root), OID_AUTO,
1193 "counter", CTLTYPE_UINT | CTLFLAG_RD, tc, sizeof(*tc),
1194 sysctl_kern_timecounter_get, "IU", "current timecounter value");
1195 SYSCTL_ADD_PROC(NULL, SYSCTL_CHILDREN(tc_root), OID_AUTO,
1196 "frequency", CTLTYPE_U64 | CTLFLAG_RD, tc, sizeof(*tc),
1197 sysctl_kern_timecounter_freq, "QU", "timecounter frequency");
1198 SYSCTL_ADD_INT(NULL, SYSCTL_CHILDREN(tc_root), OID_AUTO,
1199 "quality", CTLFLAG_RD, &(tc->tc_quality), 0,
1200 "goodness of time counter");
1201 /*
1202 * Do not automatically switch if the current tc was specifically
1203 * chosen. Never automatically use a timecounter with negative quality.
1204 * Even though we run on the dummy counter, switching here may be
1205 * worse since this timecounter may not be monotonic.
1206 */
1207 if (tc_chosen)
1208 return;
1209 if (tc->tc_quality < 0)
1210 return;
1211 if (tc->tc_quality < timecounter->tc_quality)
1212 return;
1213 if (tc->tc_quality == timecounter->tc_quality &&
1214 tc->tc_frequency < timecounter->tc_frequency)
1215 return;
1216 (void)tc->tc_get_timecount(tc);
1217 (void)tc->tc_get_timecount(tc);
1218 timecounter = tc;
1219 }
1220
1221 /* Report the frequency of the current timecounter. */
1222 uint64_t
1223 tc_getfrequency(void)
1224 {
1225
1226 return (timehands->th_counter->tc_frequency);
1227 }
1228
1229 /*
1230 * Step our concept of UTC. This is done by modifying our estimate of
1231 * when we booted.
1232 * XXX: not locked.
1233 */
1234 void
1235 tc_setclock(struct timespec *ts)
1236 {
1237 struct timespec tbef, taft;
1238 struct bintime bt, bt2;
1239
1240 cpu_tick_calibrate(1);
1241 nanotime(&tbef);
1242 timespec2bintime(ts, &bt);
1243 binuptime(&bt2);
1244 bintime_sub(&bt, &bt2);
1245 bintime_add(&bt2, &boottimebin);
1246 boottimebin = bt;
1247 bintime2timeval(&bt, &boottime);
1248
1249 /* XXX fiddle all the little crinkly bits around the fiords... */
1250 tc_windup();
1251 nanotime(&taft);
1252 if (timestepwarnings) {
1253 log(LOG_INFO,
1254 "Time stepped from %jd.%09ld to %jd.%09ld (%jd.%09ld)\n",
1255 (intmax_t)tbef.tv_sec, tbef.tv_nsec,
1256 (intmax_t)taft.tv_sec, taft.tv_nsec,
1257 (intmax_t)ts->tv_sec, ts->tv_nsec);
1258 }
1259 cpu_tick_calibrate(1);
1260 }
1261
1262 /*
1263 * Initialize the next struct timehands in the ring and make
1264 * it the active timehands. Along the way we might switch to a different
1265 * timecounter and/or do seconds processing in NTP. Slightly magic.
1266 */
1267 static void
1268 tc_windup(void)
1269 {
1270 struct bintime bt;
1271 struct timehands *th, *tho;
1272 uint64_t scale;
1273 u_int delta, ncount, ogen;
1274 int i;
1275 time_t t;
1276
1277 /*
1278 * Make the next timehands a copy of the current one, but do
1279 * not overwrite the generation or next pointer. While we
1280 * update the contents, the generation must be zero. We need
1281 * to ensure that the zero generation is visible before the
1282 * data updates become visible, which requires release fence.
1283 * For similar reasons, re-reading of the generation after the
1284 * data is read should use acquire fence.
1285 */
1286 tho = timehands;
1287 th = tho->th_next;
1288 ogen = th->th_generation;
1289 th->th_generation = 0;
1290 atomic_thread_fence_rel();
1291 bcopy(tho, th, offsetof(struct timehands, th_generation));
1292
1293 /*
1294 * Capture a timecounter delta on the current timecounter and if
1295 * changing timecounters, a counter value from the new timecounter.
1296 * Update the offset fields accordingly.
1297 */
1298 delta = tc_delta(th);
1299 if (th->th_counter != timecounter)
1300 ncount = timecounter->tc_get_timecount(timecounter);
1301 else
1302 ncount = 0;
1303 #ifdef FFCLOCK
1304 ffclock_windup(delta);
1305 #endif
1306 th->th_offset_count += delta;
1307 th->th_offset_count &= th->th_counter->tc_counter_mask;
1308 while (delta > th->th_counter->tc_frequency) {
1309 /* Eat complete unadjusted seconds. */
1310 delta -= th->th_counter->tc_frequency;
1311 th->th_offset.sec++;
1312 }
1313 if ((delta > th->th_counter->tc_frequency / 2) &&
1314 (th->th_scale * delta < ((uint64_t)1 << 63))) {
1315 /* The product th_scale * delta just barely overflows. */
1316 th->th_offset.sec++;
1317 }
1318 bintime_addx(&th->th_offset, th->th_scale * delta);
1319
1320 /*
1321 * Hardware latching timecounters may not generate interrupts on
1322 * PPS events, so instead we poll them. There is a finite risk that
1323 * the hardware might capture a count which is later than the one we
1324 * got above, and therefore possibly in the next NTP second which might
1325 * have a different rate than the current NTP second. It doesn't
1326 * matter in practice.
1327 */
1328 if (tho->th_counter->tc_poll_pps)
1329 tho->th_counter->tc_poll_pps(tho->th_counter);
1330
1331 /*
1332 * Deal with NTP second processing. The for loop normally
1333 * iterates at most once, but in extreme situations it might
1334 * keep NTP sane if timeouts are not run for several seconds.
1335 * At boot, the time step can be large when the TOD hardware
1336 * has been read, so on really large steps, we call
1337 * ntp_update_second only twice. We need to call it twice in
1338 * case we missed a leap second.
1339 */
1340 bt = th->th_offset;
1341 bintime_add(&bt, &boottimebin);
1342 i = bt.sec - tho->th_microtime.tv_sec;
1343 if (i > LARGE_STEP)
1344 i = 2;
1345 for (; i > 0; i--) {
1346 t = bt.sec;
1347 ntp_update_second(&th->th_adjustment, &bt.sec);
1348 if (bt.sec != t)
1349 boottimebin.sec += bt.sec - t;
1350 }
1351 /* Update the UTC timestamps used by the get*() functions. */
1352 /* XXX shouldn't do this here. Should force non-`get' versions. */
1353 bintime2timeval(&bt, &th->th_microtime);
1354 bintime2timespec(&bt, &th->th_nanotime);
1355
1356 /* Now is a good time to change timecounters. */
1357 if (th->th_counter != timecounter) {
1358 #ifndef __arm__
1359 if ((timecounter->tc_flags & TC_FLAGS_C2STOP) != 0)
1360 cpu_disable_c2_sleep++;
1361 if ((th->th_counter->tc_flags & TC_FLAGS_C2STOP) != 0)
1362 cpu_disable_c2_sleep--;
1363 #endif
1364 th->th_counter = timecounter;
1365 th->th_offset_count = ncount;
1366 tc_min_ticktock_freq = max(1, timecounter->tc_frequency /
1367 (((uint64_t)timecounter->tc_counter_mask + 1) / 3));
1368 #ifdef FFCLOCK
1369 ffclock_change_tc(th);
1370 #endif
1371 }
1372
1373 /*-
1374 * Recalculate the scaling factor. We want the number of 1/2^64
1375 * fractions of a second per period of the hardware counter, taking
1376 * into account the th_adjustment factor which the NTP PLL/adjtime(2)
1377 * processing provides us with.
1378 *
1379 * The th_adjustment is nanoseconds per second with 32 bit binary
1380 * fraction and we want 64 bit binary fraction of second:
1381 *
1382 * x = a * 2^32 / 10^9 = a * 4.294967296
1383 *
1384 * The range of th_adjustment is +/- 5000PPM so inside a 64bit int
1385 * we can only multiply by about 850 without overflowing, that
1386 * leaves no suitably precise fractions for multiply before divide.
1387 *
1388 * Divide before multiply with a fraction of 2199/512 results in a
1389 * systematic undercompensation of 10PPM of th_adjustment. On a
1390 * 5000PPM adjustment this is a 0.05PPM error. This is acceptable.
1391 *
1392 * We happily sacrifice the lowest of the 64 bits of our result
1393 * to the goddess of code clarity.
1394 *
1395 */
1396 scale = (uint64_t)1 << 63;
1397 scale += (th->th_adjustment / 1024) * 2199;
1398 scale /= th->th_counter->tc_frequency;
1399 th->th_scale = scale * 2;
1400
1401 /*
1402 * Now that the struct timehands is again consistent, set the new
1403 * generation number, making sure to not make it zero.
1404 */
1405 if (++ogen == 0)
1406 ogen = 1;
1407 atomic_store_rel_int(&th->th_generation, ogen);
1408
1409 /* Go live with the new struct timehands. */
1410 #ifdef FFCLOCK
1411 switch (sysclock_active) {
1412 case SYSCLOCK_FBCK:
1413 #endif
1414 time_second = th->th_microtime.tv_sec;
1415 time_uptime = th->th_offset.sec;
1416 #ifdef FFCLOCK
1417 break;
1418 case SYSCLOCK_FFWD:
1419 time_second = fftimehands->tick_time_lerp.sec;
1420 time_uptime = fftimehands->tick_time_lerp.sec - ffclock_boottime.sec;
1421 break;
1422 }
1423 #endif
1424
1425 timehands = th;
1426 timekeep_push_vdso();
1427 }
1428
1429 /* Report or change the active timecounter hardware. */
1430 static int
1431 sysctl_kern_timecounter_hardware(SYSCTL_HANDLER_ARGS)
1432 {
1433 char newname[32];
1434 struct timecounter *newtc, *tc;
1435 int error;
1436
1437 tc = timecounter;
1438 strlcpy(newname, tc->tc_name, sizeof(newname));
1439
1440 error = sysctl_handle_string(oidp, &newname[0], sizeof(newname), req);
1441 if (error != 0 || req->newptr == NULL)
1442 return (error);
1443 /* Record that the tc in use now was specifically chosen. */
1444 tc_chosen = 1;
1445 if (strcmp(newname, tc->tc_name) == 0)
1446 return (0);
1447 for (newtc = timecounters; newtc != NULL; newtc = newtc->tc_next) {
1448 if (strcmp(newname, newtc->tc_name) != 0)
1449 continue;
1450
1451 /* Warm up new timecounter. */
1452 (void)newtc->tc_get_timecount(newtc);
1453 (void)newtc->tc_get_timecount(newtc);
1454
1455 timecounter = newtc;
1456
1457 /*
1458 * The vdso timehands update is deferred until the next
1459 * 'tc_windup()'.
1460 *
1461 * This is prudent given that 'timekeep_push_vdso()' does not
1462 * use any locking and that it can be called in hard interrupt
1463 * context via 'tc_windup()'.
1464 */
1465 return (0);
1466 }
1467 return (EINVAL);
1468 }
1469
1470 SYSCTL_PROC(_kern_timecounter, OID_AUTO, hardware, CTLTYPE_STRING | CTLFLAG_RW,
1471 0, 0, sysctl_kern_timecounter_hardware, "A",
1472 "Timecounter hardware selected");
1473
1474
1475 /* Report the available timecounter hardware. */
1476 static int
1477 sysctl_kern_timecounter_choice(SYSCTL_HANDLER_ARGS)
1478 {
1479 struct sbuf sb;
1480 struct timecounter *tc;
1481 int error;
1482
1483 sbuf_new_for_sysctl(&sb, NULL, 0, req);
1484 for (tc = timecounters; tc != NULL; tc = tc->tc_next) {
1485 if (tc != timecounters)
1486 sbuf_putc(&sb, ' ');
1487 sbuf_printf(&sb, "%s(%d)", tc->tc_name, tc->tc_quality);
1488 }
1489 error = sbuf_finish(&sb);
1490 sbuf_delete(&sb);
1491 return (error);
1492 }
1493
1494 SYSCTL_PROC(_kern_timecounter, OID_AUTO, choice, CTLTYPE_STRING | CTLFLAG_RD,
1495 0, 0, sysctl_kern_timecounter_choice, "A", "Timecounter hardware detected");
1496
1497 /*
1498 * RFC 2783 PPS-API implementation.
1499 */
1500
1501 /*
1502 * Return true if the driver is aware of the abi version extensions in the
1503 * pps_state structure, and it supports at least the given abi version number.
1504 */
1505 static inline int
1506 abi_aware(struct pps_state *pps, int vers)
1507 {
1508
1509 return ((pps->kcmode & KCMODE_ABIFLAG) && pps->driver_abi >= vers);
1510 }
1511
1512 static int
1513 pps_fetch(struct pps_fetch_args *fapi, struct pps_state *pps)
1514 {
1515 int err, timo;
1516 pps_seq_t aseq, cseq;
1517 struct timeval tv;
1518
1519 if (fapi->tsformat && fapi->tsformat != PPS_TSFMT_TSPEC)
1520 return (EINVAL);
1521
1522 /*
1523 * If no timeout is requested, immediately return whatever values were
1524 * most recently captured. If timeout seconds is -1, that's a request
1525 * to block without a timeout. WITNESS won't let us sleep forever
1526 * without a lock (we really don't need a lock), so just repeatedly
1527 * sleep a long time.
1528 */
1529 if (fapi->timeout.tv_sec || fapi->timeout.tv_nsec) {
1530 if (fapi->timeout.tv_sec == -1)
1531 timo = 0x7fffffff;
1532 else {
1533 tv.tv_sec = fapi->timeout.tv_sec;
1534 tv.tv_usec = fapi->timeout.tv_nsec / 1000;
1535 timo = tvtohz(&tv);
1536 }
1537 aseq = pps->ppsinfo.assert_sequence;
1538 cseq = pps->ppsinfo.clear_sequence;
1539 while (aseq == pps->ppsinfo.assert_sequence &&
1540 cseq == pps->ppsinfo.clear_sequence) {
1541 if (abi_aware(pps, 1) && pps->driver_mtx != NULL) {
1542 if (pps->flags & PPSFLAG_MTX_SPIN) {
1543 err = msleep_spin(pps, pps->driver_mtx,
1544 "ppsfch", timo);
1545 } else {
1546 err = msleep(pps, pps->driver_mtx, PCATCH,
1547 "ppsfch", timo);
1548 }
1549 } else {
1550 err = tsleep(pps, PCATCH, "ppsfch", timo);
1551 }
1552 if (err == EWOULDBLOCK) {
1553 if (fapi->timeout.tv_sec == -1) {
1554 continue;
1555 } else {
1556 return (ETIMEDOUT);
1557 }
1558 } else if (err != 0) {
1559 return (err);
1560 }
1561 }
1562 }
1563
1564 pps->ppsinfo.current_mode = pps->ppsparam.mode;
1565 fapi->pps_info_buf = pps->ppsinfo;
1566
1567 return (0);
1568 }
1569
1570 int
1571 pps_ioctl(u_long cmd, caddr_t data, struct pps_state *pps)
1572 {
1573 pps_params_t *app;
1574 struct pps_fetch_args *fapi;
1575 #ifdef FFCLOCK
1576 struct pps_fetch_ffc_args *fapi_ffc;
1577 #endif
1578 #ifdef PPS_SYNC
1579 struct pps_kcbind_args *kapi;
1580 #endif
1581
1582 KASSERT(pps != NULL, ("NULL pps pointer in pps_ioctl"));
1583 switch (cmd) {
1584 case PPS_IOC_CREATE:
1585 return (0);
1586 case PPS_IOC_DESTROY:
1587 return (0);
1588 case PPS_IOC_SETPARAMS:
1589 app = (pps_params_t *)data;
1590 if (app->mode & ~pps->ppscap)
1591 return (EINVAL);
1592 #ifdef FFCLOCK
1593 /* Ensure only a single clock is selected for ffc timestamp. */
1594 if ((app->mode & PPS_TSCLK_MASK) == PPS_TSCLK_MASK)
1595 return (EINVAL);
1596 #endif
1597 pps->ppsparam = *app;
1598 return (0);
1599 case PPS_IOC_GETPARAMS:
1600 app = (pps_params_t *)data;
1601 *app = pps->ppsparam;
1602 app->api_version = PPS_API_VERS_1;
1603 return (0);
1604 case PPS_IOC_GETCAP:
1605 *(int*)data = pps->ppscap;
1606 return (0);
1607 case PPS_IOC_FETCH:
1608 fapi = (struct pps_fetch_args *)data;
1609 return (pps_fetch(fapi, pps));
1610 #ifdef FFCLOCK
1611 case PPS_IOC_FETCH_FFCOUNTER:
1612 fapi_ffc = (struct pps_fetch_ffc_args *)data;
1613 if (fapi_ffc->tsformat && fapi_ffc->tsformat !=
1614 PPS_TSFMT_TSPEC)
1615 return (EINVAL);
1616 if (fapi_ffc->timeout.tv_sec || fapi_ffc->timeout.tv_nsec)
1617 return (EOPNOTSUPP);
1618 pps->ppsinfo_ffc.current_mode = pps->ppsparam.mode;
1619 fapi_ffc->pps_info_buf_ffc = pps->ppsinfo_ffc;
1620 /* Overwrite timestamps if feedback clock selected. */
1621 switch (pps->ppsparam.mode & PPS_TSCLK_MASK) {
1622 case PPS_TSCLK_FBCK:
1623 fapi_ffc->pps_info_buf_ffc.assert_timestamp =
1624 pps->ppsinfo.assert_timestamp;
1625 fapi_ffc->pps_info_buf_ffc.clear_timestamp =
1626 pps->ppsinfo.clear_timestamp;
1627 break;
1628 case PPS_TSCLK_FFWD:
1629 break;
1630 default:
1631 break;
1632 }
1633 return (0);
1634 #endif /* FFCLOCK */
1635 case PPS_IOC_KCBIND:
1636 #ifdef PPS_SYNC
1637 kapi = (struct pps_kcbind_args *)data;
1638 /* XXX Only root should be able to do this */
1639 if (kapi->tsformat && kapi->tsformat != PPS_TSFMT_TSPEC)
1640 return (EINVAL);
1641 if (kapi->kernel_consumer != PPS_KC_HARDPPS)
1642 return (EINVAL);
1643 if (kapi->edge & ~pps->ppscap)
1644 return (EINVAL);
1645 pps->kcmode = (kapi->edge & KCMODE_EDGEMASK) |
1646 (pps->kcmode & KCMODE_ABIFLAG);
1647 return (0);
1648 #else
1649 return (EOPNOTSUPP);
1650 #endif
1651 default:
1652 return (ENOIOCTL);
1653 }
1654 }
1655
1656 void
1657 pps_init(struct pps_state *pps)
1658 {
1659 pps->ppscap |= PPS_TSFMT_TSPEC | PPS_CANWAIT;
1660 if (pps->ppscap & PPS_CAPTUREASSERT)
1661 pps->ppscap |= PPS_OFFSETASSERT;
1662 if (pps->ppscap & PPS_CAPTURECLEAR)
1663 pps->ppscap |= PPS_OFFSETCLEAR;
1664 #ifdef FFCLOCK
1665 pps->ppscap |= PPS_TSCLK_MASK;
1666 #endif
1667 pps->kcmode &= ~KCMODE_ABIFLAG;
1668 }
1669
1670 void
1671 pps_init_abi(struct pps_state *pps)
1672 {
1673
1674 pps_init(pps);
1675 if (pps->driver_abi > 0) {
1676 pps->kcmode |= KCMODE_ABIFLAG;
1677 pps->kernel_abi = PPS_ABI_VERSION;
1678 }
1679 }
1680
1681 void
1682 pps_capture(struct pps_state *pps)
1683 {
1684 struct timehands *th;
1685
1686 KASSERT(pps != NULL, ("NULL pps pointer in pps_capture"));
1687 th = timehands;
1688 pps->capgen = atomic_load_acq_int(&th->th_generation);
1689 pps->capth = th;
1690 #ifdef FFCLOCK
1691 pps->capffth = fftimehands;
1692 #endif
1693 pps->capcount = th->th_counter->tc_get_timecount(th->th_counter);
1694 atomic_thread_fence_acq();
1695 if (pps->capgen != th->th_generation)
1696 pps->capgen = 0;
1697 }
1698
1699 void
1700 pps_event(struct pps_state *pps, int event)
1701 {
1702 struct bintime bt;
1703 struct timespec ts, *tsp, *osp;
1704 u_int tcount, *pcount;
1705 int foff;
1706 pps_seq_t *pseq;
1707 #ifdef FFCLOCK
1708 struct timespec *tsp_ffc;
1709 pps_seq_t *pseq_ffc;
1710 ffcounter *ffcount;
1711 #endif
1712 #ifdef PPS_SYNC
1713 int fhard;
1714 #endif
1715
1716 KASSERT(pps != NULL, ("NULL pps pointer in pps_event"));
1717 /* Nothing to do if not currently set to capture this event type. */
1718 if ((event & pps->ppsparam.mode) == 0)
1719 return;
1720 /* If the timecounter was wound up underneath us, bail out. */
1721 if (pps->capgen == 0 || pps->capgen !=
1722 atomic_load_acq_int(&pps->capth->th_generation))
1723 return;
1724
1725 /* Things would be easier with arrays. */
1726 if (event == PPS_CAPTUREASSERT) {
1727 tsp = &pps->ppsinfo.assert_timestamp;
1728 osp = &pps->ppsparam.assert_offset;
1729 foff = pps->ppsparam.mode & PPS_OFFSETASSERT;
1730 #ifdef PPS_SYNC
1731 fhard = pps->kcmode & PPS_CAPTUREASSERT;
1732 #endif
1733 pcount = &pps->ppscount[0];
1734 pseq = &pps->ppsinfo.assert_sequence;
1735 #ifdef FFCLOCK
1736 ffcount = &pps->ppsinfo_ffc.assert_ffcount;
1737 tsp_ffc = &pps->ppsinfo_ffc.assert_timestamp;
1738 pseq_ffc = &pps->ppsinfo_ffc.assert_sequence;
1739 #endif
1740 } else {
1741 tsp = &pps->ppsinfo.clear_timestamp;
1742 osp = &pps->ppsparam.clear_offset;
1743 foff = pps->ppsparam.mode & PPS_OFFSETCLEAR;
1744 #ifdef PPS_SYNC
1745 fhard = pps->kcmode & PPS_CAPTURECLEAR;
1746 #endif
1747 pcount = &pps->ppscount[1];
1748 pseq = &pps->ppsinfo.clear_sequence;
1749 #ifdef FFCLOCK
1750 ffcount = &pps->ppsinfo_ffc.clear_ffcount;
1751 tsp_ffc = &pps->ppsinfo_ffc.clear_timestamp;
1752 pseq_ffc = &pps->ppsinfo_ffc.clear_sequence;
1753 #endif
1754 }
1755
1756 /*
1757 * If the timecounter changed, we cannot compare the count values, so
1758 * we have to drop the rest of the PPS-stuff until the next event.
1759 */
1760 if (pps->ppstc != pps->capth->th_counter) {
1761 pps->ppstc = pps->capth->th_counter;
1762 *pcount = pps->capcount;
1763 pps->ppscount[2] = pps->capcount;
1764 return;
1765 }
1766
1767 /* Convert the count to a timespec. */
1768 tcount = pps->capcount - pps->capth->th_offset_count;
1769 tcount &= pps->capth->th_counter->tc_counter_mask;
1770 bt = pps->capth->th_offset;
1771 bintime_addx(&bt, pps->capth->th_scale * tcount);
1772 bintime_add(&bt, &boottimebin);
1773 bintime2timespec(&bt, &ts);
1774
1775 /* If the timecounter was wound up underneath us, bail out. */
1776 atomic_thread_fence_acq();
1777 if (pps->capgen != pps->capth->th_generation)
1778 return;
1779
1780 *pcount = pps->capcount;
1781 (*pseq)++;
1782 *tsp = ts;
1783
1784 if (foff) {
1785 timespecadd(tsp, osp);
1786 if (tsp->tv_nsec < 0) {
1787 tsp->tv_nsec += 1000000000;
1788 tsp->tv_sec -= 1;
1789 }
1790 }
1791
1792 #ifdef FFCLOCK
1793 *ffcount = pps->capffth->tick_ffcount + tcount;
1794 bt = pps->capffth->tick_time;
1795 ffclock_convert_delta(tcount, pps->capffth->cest.period, &bt);
1796 bintime_add(&bt, &pps->capffth->tick_time);
1797 bintime2timespec(&bt, &ts);
1798 (*pseq_ffc)++;
1799 *tsp_ffc = ts;
1800 #endif
1801
1802 #ifdef PPS_SYNC
1803 if (fhard) {
1804 uint64_t scale;
1805
1806 /*
1807 * Feed the NTP PLL/FLL.
1808 * The FLL wants to know how many (hardware) nanoseconds
1809 * elapsed since the previous event.
1810 */
1811 tcount = pps->capcount - pps->ppscount[2];
1812 pps->ppscount[2] = pps->capcount;
1813 tcount &= pps->capth->th_counter->tc_counter_mask;
1814 scale = (uint64_t)1 << 63;
1815 scale /= pps->capth->th_counter->tc_frequency;
1816 scale *= 2;
1817 bt.sec = 0;
1818 bt.frac = 0;
1819 bintime_addx(&bt, scale * tcount);
1820 bintime2timespec(&bt, &ts);
1821 hardpps(tsp, ts.tv_nsec + 1000000000 * ts.tv_sec);
1822 }
1823 #endif
1824
1825 /* Wakeup anyone sleeping in pps_fetch(). */
1826 wakeup(pps);
1827 }
1828
1829 /*
1830 * Timecounters need to be updated every so often to prevent the hardware
1831 * counter from overflowing. Updating also recalculates the cached values
1832 * used by the get*() family of functions, so their precision depends on
1833 * the update frequency.
1834 */
1835
1836 static int tc_tick;
1837 SYSCTL_INT(_kern_timecounter, OID_AUTO, tick, CTLFLAG_RD, &tc_tick, 0,
1838 "Approximate number of hardclock ticks in a millisecond");
1839
1840 void
1841 tc_ticktock(int cnt)
1842 {
1843 static int count;
1844
1845 count += cnt;
1846 if (count < tc_tick)
1847 return;
1848 count = 0;
1849 tc_windup();
1850 }
1851
1852 static void __inline
1853 tc_adjprecision(void)
1854 {
1855 int t;
1856
1857 if (tc_timepercentage > 0) {
1858 t = (99 + tc_timepercentage) / tc_timepercentage;
1859 tc_precexp = fls(t + (t >> 1)) - 1;
1860 FREQ2BT(hz / tc_tick, &bt_timethreshold);
1861 FREQ2BT(hz, &bt_tickthreshold);
1862 bintime_shift(&bt_timethreshold, tc_precexp);
1863 bintime_shift(&bt_tickthreshold, tc_precexp);
1864 } else {
1865 tc_precexp = 31;
1866 bt_timethreshold.sec = INT_MAX;
1867 bt_timethreshold.frac = ~(uint64_t)0;
1868 bt_tickthreshold = bt_timethreshold;
1869 }
1870 sbt_timethreshold = bttosbt(bt_timethreshold);
1871 sbt_tickthreshold = bttosbt(bt_tickthreshold);
1872 }
1873
1874 static int
1875 sysctl_kern_timecounter_adjprecision(SYSCTL_HANDLER_ARGS)
1876 {
1877 int error, val;
1878
1879 val = tc_timepercentage;
1880 error = sysctl_handle_int(oidp, &val, 0, req);
1881 if (error != 0 || req->newptr == NULL)
1882 return (error);
1883 tc_timepercentage = val;
1884 if (cold)
1885 goto done;
1886 tc_adjprecision();
1887 done:
1888 return (0);
1889 }
1890
1891 static void
1892 inittimecounter(void *dummy)
1893 {
1894 u_int p;
1895 int tick_rate;
1896
1897 /*
1898 * Set the initial timeout to
1899 * max(1, <approx. number of hardclock ticks in a millisecond>).
1900 * People should probably not use the sysctl to set the timeout
1901 * to smaller than its initial value, since that value is the
1902 * smallest reasonable one. If they want better timestamps they
1903 * should use the non-"get"* functions.
1904 */
1905 if (hz > 1000)
1906 tc_tick = (hz + 500) / 1000;
1907 else
1908 tc_tick = 1;
1909 tc_adjprecision();
1910 FREQ2BT(hz, &tick_bt);
1911 tick_sbt = bttosbt(tick_bt);
1912 tick_rate = hz / tc_tick;
1913 FREQ2BT(tick_rate, &tc_tick_bt);
1914 tc_tick_sbt = bttosbt(tc_tick_bt);
1915 p = (tc_tick * 1000000) / hz;
1916 printf("Timecounters tick every %d.%03u msec\n", p / 1000, p % 1000);
1917
1918 #ifdef FFCLOCK
1919 ffclock_init();
1920 #endif
1921 /* warm up new timecounter (again) and get rolling. */
1922 (void)timecounter->tc_get_timecount(timecounter);
1923 (void)timecounter->tc_get_timecount(timecounter);
1924 tc_windup();
1925 }
1926
1927 SYSINIT(timecounter, SI_SUB_CLOCKS, SI_ORDER_SECOND, inittimecounter, NULL);
1928
1929 /* Cpu tick handling -------------------------------------------------*/
1930
1931 static int cpu_tick_variable;
1932 static uint64_t cpu_tick_frequency;
1933
1934 static DPCPU_DEFINE(uint64_t, tc_cpu_ticks_base);
1935 static DPCPU_DEFINE(unsigned, tc_cpu_ticks_last);
1936
1937 static uint64_t
1938 tc_cpu_ticks(void)
1939 {
1940 struct timecounter *tc;
1941 uint64_t res, *base;
1942 unsigned u, *last;
1943
1944 critical_enter();
1945 base = DPCPU_PTR(tc_cpu_ticks_base);
1946 last = DPCPU_PTR(tc_cpu_ticks_last);
1947 tc = timehands->th_counter;
1948 u = tc->tc_get_timecount(tc) & tc->tc_counter_mask;
1949 if (u < *last)
1950 *base += (uint64_t)tc->tc_counter_mask + 1;
1951 *last = u;
1952 res = u + *base;
1953 critical_exit();
1954 return (res);
1955 }
1956
1957 void
1958 cpu_tick_calibration(void)
1959 {
1960 static time_t last_calib;
1961
1962 if (time_uptime != last_calib && !(time_uptime & 0xf)) {
1963 cpu_tick_calibrate(0);
1964 last_calib = time_uptime;
1965 }
1966 }
1967
1968 /*
1969 * This function gets called every 16 seconds on only one designated
1970 * CPU in the system from hardclock() via cpu_tick_calibration()().
1971 *
1972 * Whenever the real time clock is stepped we get called with reset=1
1973 * to make sure we handle suspend/resume and similar events correctly.
1974 */
1975
1976 static void
1977 cpu_tick_calibrate(int reset)
1978 {
1979 static uint64_t c_last;
1980 uint64_t c_this, c_delta;
1981 static struct bintime t_last;
1982 struct bintime t_this, t_delta;
1983 uint32_t divi;
1984
1985 if (reset) {
1986 /* The clock was stepped, abort & reset */
1987 t_last.sec = 0;
1988 return;
1989 }
1990
1991 /* we don't calibrate fixed rate cputicks */
1992 if (!cpu_tick_variable)
1993 return;
1994
1995 getbinuptime(&t_this);
1996 c_this = cpu_ticks();
1997 if (t_last.sec != 0) {
1998 c_delta = c_this - c_last;
1999 t_delta = t_this;
2000 bintime_sub(&t_delta, &t_last);
2001 /*
2002 * Headroom:
2003 * 2^(64-20) / 16[s] =
2004 * 2^(44) / 16[s] =
2005 * 17.592.186.044.416 / 16 =
2006 * 1.099.511.627.776 [Hz]
2007 */
2008 divi = t_delta.sec << 20;
2009 divi |= t_delta.frac >> (64 - 20);
2010 c_delta <<= 20;
2011 c_delta /= divi;
2012 if (c_delta > cpu_tick_frequency) {
2013 if (0 && bootverbose)
2014 printf("cpu_tick increased to %ju Hz\n",
2015 c_delta);
2016 cpu_tick_frequency = c_delta;
2017 }
2018 }
2019 c_last = c_this;
2020 t_last = t_this;
2021 }
2022
2023 void
2024 set_cputicker(cpu_tick_f *func, uint64_t freq, unsigned var)
2025 {
2026
2027 if (func == NULL) {
2028 cpu_ticks = tc_cpu_ticks;
2029 } else {
2030 cpu_tick_frequency = freq;
2031 cpu_tick_variable = var;
2032 cpu_ticks = func;
2033 }
2034 }
2035
2036 uint64_t
2037 cpu_tickrate(void)
2038 {
2039
2040 if (cpu_ticks == tc_cpu_ticks)
2041 return (tc_getfrequency());
2042 return (cpu_tick_frequency);
2043 }
2044
2045 /*
2046 * We need to be slightly careful converting cputicks to microseconds.
2047 * There is plenty of margin in 64 bits of microseconds (half a million
2048 * years) and in 64 bits at 4 GHz (146 years), but if we do a multiply
2049 * before divide conversion (to retain precision) we find that the
2050 * margin shrinks to 1.5 hours (one millionth of 146y).
2051 * With a three prong approach we never lose significant bits, no
2052 * matter what the cputick rate and length of timeinterval is.
2053 */
2054
2055 uint64_t
2056 cputick2usec(uint64_t tick)
2057 {
2058
2059 if (tick > 18446744073709551LL) /* floor(2^64 / 1000) */
2060 return (tick / (cpu_tickrate() / 1000000LL));
2061 else if (tick > 18446744073709LL) /* floor(2^64 / 1000000) */
2062 return ((tick * 1000LL) / (cpu_tickrate() / 1000LL));
2063 else
2064 return ((tick * 1000000LL) / cpu_tickrate());
2065 }
2066
2067 cpu_tick_f *cpu_ticks = tc_cpu_ticks;
2068
2069 static int vdso_th_enable = 1;
2070 static int
2071 sysctl_fast_gettime(SYSCTL_HANDLER_ARGS)
2072 {
2073 int old_vdso_th_enable, error;
2074
2075 old_vdso_th_enable = vdso_th_enable;
2076 error = sysctl_handle_int(oidp, &old_vdso_th_enable, 0, req);
2077 if (error != 0)
2078 return (error);
2079 vdso_th_enable = old_vdso_th_enable;
2080 return (0);
2081 }
2082 SYSCTL_PROC(_kern_timecounter, OID_AUTO, fast_gettime,
2083 CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE,
2084 NULL, 0, sysctl_fast_gettime, "I", "Enable fast time of day");
2085
2086 uint32_t
2087 tc_fill_vdso_timehands(struct vdso_timehands *vdso_th)
2088 {
2089 struct timehands *th;
2090 uint32_t enabled;
2091
2092 th = timehands;
2093 vdso_th->th_algo = VDSO_TH_ALGO_1;
2094 vdso_th->th_scale = th->th_scale;
2095 vdso_th->th_offset_count = th->th_offset_count;
2096 vdso_th->th_counter_mask = th->th_counter->tc_counter_mask;
2097 vdso_th->th_offset = th->th_offset;
2098 vdso_th->th_boottime = boottimebin;
2099 enabled = cpu_fill_vdso_timehands(vdso_th, th->th_counter);
2100 if (!vdso_th_enable)
2101 enabled = 0;
2102 return (enabled);
2103 }
2104
2105 #ifdef COMPAT_FREEBSD32
2106 uint32_t
2107 tc_fill_vdso_timehands32(struct vdso_timehands32 *vdso_th32)
2108 {
2109 struct timehands *th;
2110 uint32_t enabled;
2111
2112 th = timehands;
2113 vdso_th32->th_algo = VDSO_TH_ALGO_1;
2114 *(uint64_t *)&vdso_th32->th_scale[0] = th->th_scale;
2115 vdso_th32->th_offset_count = th->th_offset_count;
2116 vdso_th32->th_counter_mask = th->th_counter->tc_counter_mask;
2117 vdso_th32->th_offset.sec = th->th_offset.sec;
2118 *(uint64_t *)&vdso_th32->th_offset.frac[0] = th->th_offset.frac;
2119 vdso_th32->th_boottime.sec = boottimebin.sec;
2120 *(uint64_t *)&vdso_th32->th_boottime.frac[0] = boottimebin.frac;
2121 enabled = cpu_fill_vdso_timehands32(vdso_th32, th->th_counter);
2122 if (!vdso_th_enable)
2123 enabled = 0;
2124 return (enabled);
2125 }
2126 #endif
Cache object: 42b62932986dbe98b6fbe4b89693e891
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