xref: /dragonfly/sys/kern/kern_clock.c (revision 9f3fc534)
1 /*
2  * Copyright (c) 2003,2004 The DragonFly Project.  All rights reserved.
3  *
4  * This code is derived from software contributed to The DragonFly Project
5  * by Matthew Dillon <dillon@backplane.com>
6  *
7  * Redistribution and use in source and binary forms, with or without
8  * modification, are permitted provided that the following conditions
9  * are met:
10  *
11  * 1. Redistributions of source code must retain the above copyright
12  *    notice, this list of conditions and the following disclaimer.
13  * 2. Redistributions in binary form must reproduce the above copyright
14  *    notice, this list of conditions and the following disclaimer in
15  *    the documentation and/or other materials provided with the
16  *    distribution.
17  * 3. Neither the name of The DragonFly Project nor the names of its
18  *    contributors may be used to endorse or promote products derived
19  *    from this software without specific, prior written permission.
20  *
21  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
22  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
23  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
24  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
25  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
26  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
27  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
28  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
29  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
30  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
31  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
32  * SUCH DAMAGE.
33  *
34  * Copyright (c) 1997, 1998 Poul-Henning Kamp <phk@FreeBSD.org>
35  * Copyright (c) 1982, 1986, 1991, 1993
36  *	The Regents of the University of California.  All rights reserved.
37  * (c) UNIX System Laboratories, Inc.
38  * All or some portions of this file are derived from material licensed
39  * to the University of California by American Telephone and Telegraph
40  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
41  * the permission of UNIX System Laboratories, Inc.
42  *
43  * Redistribution and use in source and binary forms, with or without
44  * modification, are permitted provided that the following conditions
45  * are met:
46  * 1. Redistributions of source code must retain the above copyright
47  *    notice, this list of conditions and the following disclaimer.
48  * 2. Redistributions in binary form must reproduce the above copyright
49  *    notice, this list of conditions and the following disclaimer in the
50  *    documentation and/or other materials provided with the distribution.
51  * 3. All advertising materials mentioning features or use of this software
52  *    must display the following acknowledgement:
53  *	This product includes software developed by the University of
54  *	California, Berkeley and its contributors.
55  * 4. Neither the name of the University nor the names of its contributors
56  *    may be used to endorse or promote products derived from this software
57  *    without specific prior written permission.
58  *
59  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
60  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
61  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
62  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
63  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
64  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
65  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
66  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
67  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
68  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
69  * SUCH DAMAGE.
70  *
71  *	@(#)kern_clock.c	8.5 (Berkeley) 1/21/94
72  * $FreeBSD: src/sys/kern/kern_clock.c,v 1.105.2.10 2002/10/17 13:19:40 maxim Exp $
73  * $DragonFly: src/sys/kern/kern_clock.c,v 1.62 2008/09/09 04:06:13 dillon Exp $
74  */
75 
76 #include "opt_ntp.h"
77 #include "opt_polling.h"
78 #include "opt_ifpoll.h"
79 #include "opt_pctrack.h"
80 
81 #include <sys/param.h>
82 #include <sys/systm.h>
83 #include <sys/callout.h>
84 #include <sys/kernel.h>
85 #include <sys/kinfo.h>
86 #include <sys/proc.h>
87 #include <sys/malloc.h>
88 #include <sys/resourcevar.h>
89 #include <sys/signalvar.h>
90 #include <sys/timex.h>
91 #include <sys/timepps.h>
92 #include <vm/vm.h>
93 #include <sys/lock.h>
94 #include <vm/pmap.h>
95 #include <vm/vm_map.h>
96 #include <vm/vm_extern.h>
97 #include <sys/sysctl.h>
98 #include <sys/thread2.h>
99 
100 #include <machine/cpu.h>
101 #include <machine/limits.h>
102 #include <machine/smp.h>
103 
104 #ifdef GPROF
105 #include <sys/gmon.h>
106 #endif
107 
108 #ifdef DEVICE_POLLING
109 extern void init_device_poll_pcpu(int);
110 #endif
111 
112 #ifdef IFPOLL_ENABLE
113 extern void ifpoll_init_pcpu(int);
114 #endif
115 
116 #ifdef DEBUG_PCTRACK
117 static void do_pctrack(struct intrframe *frame, int which);
118 #endif
119 
120 static void initclocks (void *dummy);
121 SYSINIT(clocks, SI_BOOT2_CLOCKS, SI_ORDER_FIRST, initclocks, NULL)
122 
123 /*
124  * Some of these don't belong here, but it's easiest to concentrate them.
125  * Note that cpu_time counts in microseconds, but most userland programs
126  * just compare relative times against the total by delta.
127  */
128 struct kinfo_cputime cputime_percpu[MAXCPU];
129 #ifdef DEBUG_PCTRACK
130 struct kinfo_pcheader cputime_pcheader = { PCTRACK_SIZE, PCTRACK_ARYSIZE };
131 struct kinfo_pctrack cputime_pctrack[MAXCPU][PCTRACK_SIZE];
132 #endif
133 
134 #ifdef SMP
135 static int
136 sysctl_cputime(SYSCTL_HANDLER_ARGS)
137 {
138 	int cpu, error = 0;
139 	size_t size = sizeof(struct kinfo_cputime);
140 
141 	for (cpu = 0; cpu < ncpus; ++cpu) {
142 		if ((error = SYSCTL_OUT(req, &cputime_percpu[cpu], size)))
143 			break;
144 	}
145 
146 	return (error);
147 }
148 SYSCTL_PROC(_kern, OID_AUTO, cputime, (CTLTYPE_OPAQUE|CTLFLAG_RD), 0, 0,
149 	sysctl_cputime, "S,kinfo_cputime", "CPU time statistics");
150 #else
151 SYSCTL_STRUCT(_kern, OID_AUTO, cputime, CTLFLAG_RD, &cpu_time, kinfo_cputime,
152     "CPU time statistics");
153 #endif
154 
155 /*
156  * boottime is used to calculate the 'real' uptime.  Do not confuse this with
157  * microuptime().  microtime() is not drift compensated.  The real uptime
158  * with compensation is nanotime() - bootime.  boottime is recalculated
159  * whenever the real time is set based on the compensated elapsed time
160  * in seconds (gd->gd_time_seconds).
161  *
162  * The gd_time_seconds and gd_cpuclock_base fields remain fairly monotonic.
163  * Slight adjustments to gd_cpuclock_base are made to phase-lock it to
164  * the real time.
165  */
166 struct timespec boottime;	/* boot time (realtime) for reference only */
167 time_t time_second;		/* read-only 'passive' uptime in seconds */
168 
169 /*
170  * basetime is used to calculate the compensated real time of day.  The
171  * basetime can be modified on a per-tick basis by the adjtime(),
172  * ntp_adjtime(), and sysctl-based time correction APIs.
173  *
174  * Note that frequency corrections can also be made by adjusting
175  * gd_cpuclock_base.
176  *
177  * basetime is a tail-chasing FIFO, updated only by cpu #0.  The FIFO is
178  * used on both SMP and UP systems to avoid MP races between cpu's and
179  * interrupt races on UP systems.
180  */
181 #define BASETIME_ARYSIZE	16
182 #define BASETIME_ARYMASK	(BASETIME_ARYSIZE - 1)
183 static struct timespec basetime[BASETIME_ARYSIZE];
184 static volatile int basetime_index;
185 
186 static int
187 sysctl_get_basetime(SYSCTL_HANDLER_ARGS)
188 {
189 	struct timespec *bt;
190 	int error;
191 	int index;
192 
193 	/*
194 	 * Because basetime data and index may be updated by another cpu,
195 	 * a load fence is required to ensure that the data we read has
196 	 * not been speculatively read relative to a possibly updated index.
197 	 */
198 	index = basetime_index;
199 	cpu_lfence();
200 	bt = &basetime[index];
201 	error = SYSCTL_OUT(req, bt, sizeof(*bt));
202 	return (error);
203 }
204 
205 SYSCTL_STRUCT(_kern, KERN_BOOTTIME, boottime, CTLFLAG_RD,
206     &boottime, timespec, "System boottime");
207 SYSCTL_PROC(_kern, OID_AUTO, basetime, CTLTYPE_STRUCT|CTLFLAG_RD, 0, 0,
208     sysctl_get_basetime, "S,timespec", "System basetime");
209 
210 static void hardclock(systimer_t info, struct intrframe *frame);
211 static void statclock(systimer_t info, struct intrframe *frame);
212 static void schedclock(systimer_t info, struct intrframe *frame);
213 static void getnanotime_nbt(struct timespec *nbt, struct timespec *tsp);
214 
215 int	ticks;			/* system master ticks at hz */
216 int	clocks_running;		/* tsleep/timeout clocks operational */
217 int64_t	nsec_adj;		/* ntpd per-tick adjustment in nsec << 32 */
218 int64_t	nsec_acc;		/* accumulator */
219 
220 /* NTPD time correction fields */
221 int64_t	ntp_tick_permanent;	/* per-tick adjustment in nsec << 32 */
222 int64_t	ntp_tick_acc;		/* accumulator for per-tick adjustment */
223 int64_t	ntp_delta;		/* one-time correction in nsec */
224 int64_t ntp_big_delta = 1000000000;
225 int32_t	ntp_tick_delta;		/* current adjustment rate */
226 int32_t	ntp_default_tick_delta;	/* adjustment rate for ntp_delta */
227 time_t	ntp_leap_second;	/* time of next leap second */
228 int	ntp_leap_insert;	/* whether to insert or remove a second */
229 
230 /*
231  * Finish initializing clock frequencies and start all clocks running.
232  */
233 /* ARGSUSED*/
234 static void
235 initclocks(void *dummy)
236 {
237 	/*psratio = profhz / stathz;*/
238 	initclocks_pcpu();
239 	clocks_running = 1;
240 }
241 
242 /*
243  * Called on a per-cpu basis
244  */
245 void
246 initclocks_pcpu(void)
247 {
248 	struct globaldata *gd = mycpu;
249 
250 	crit_enter();
251 	if (gd->gd_cpuid == 0) {
252 	    gd->gd_time_seconds = 1;
253 	    gd->gd_cpuclock_base = sys_cputimer->count();
254 	} else {
255 	    /* XXX */
256 	    gd->gd_time_seconds = globaldata_find(0)->gd_time_seconds;
257 	    gd->gd_cpuclock_base = globaldata_find(0)->gd_cpuclock_base;
258 	}
259 
260 	systimer_intr_enable();
261 
262 #ifdef DEVICE_POLLING
263 	init_device_poll_pcpu(gd->gd_cpuid);
264 #endif
265 
266 #ifdef IFPOLL_ENABLE
267 	ifpoll_init_pcpu(gd->gd_cpuid);
268 #endif
269 
270 	/*
271 	 * Use a non-queued periodic systimer to prevent multiple ticks from
272 	 * building up if the sysclock jumps forward (8254 gets reset).  The
273 	 * sysclock will never jump backwards.  Our time sync is based on
274 	 * the actual sysclock, not the ticks count.
275 	 */
276 	systimer_init_periodic_nq(&gd->gd_hardclock, hardclock, NULL, hz);
277 	systimer_init_periodic_nq(&gd->gd_statclock, statclock, NULL, stathz);
278 	/* XXX correct the frequency for scheduler / estcpu tests */
279 	systimer_init_periodic_nq(&gd->gd_schedclock, schedclock,
280 				NULL, ESTCPUFREQ);
281 	crit_exit();
282 }
283 
284 /*
285  * This sets the current real time of day.  Timespecs are in seconds and
286  * nanoseconds.  We do not mess with gd_time_seconds and gd_cpuclock_base,
287  * instead we adjust basetime so basetime + gd_* results in the current
288  * time of day.  This way the gd_* fields are guarenteed to represent
289  * a monotonically increasing 'uptime' value.
290  *
291  * When set_timeofday() is called from userland, the system call forces it
292  * onto cpu #0 since only cpu #0 can update basetime_index.
293  */
294 void
295 set_timeofday(struct timespec *ts)
296 {
297 	struct timespec *nbt;
298 	int ni;
299 
300 	/*
301 	 * XXX SMP / non-atomic basetime updates
302 	 */
303 	crit_enter();
304 	ni = (basetime_index + 1) & BASETIME_ARYMASK;
305 	nbt = &basetime[ni];
306 	nanouptime(nbt);
307 	nbt->tv_sec = ts->tv_sec - nbt->tv_sec;
308 	nbt->tv_nsec = ts->tv_nsec - nbt->tv_nsec;
309 	if (nbt->tv_nsec < 0) {
310 	    nbt->tv_nsec += 1000000000;
311 	    --nbt->tv_sec;
312 	}
313 
314 	/*
315 	 * Note that basetime diverges from boottime as the clock drift is
316 	 * compensated for, so we cannot do away with boottime.  When setting
317 	 * the absolute time of day the drift is 0 (for an instant) and we
318 	 * can simply assign boottime to basetime.
319 	 *
320 	 * Note that nanouptime() is based on gd_time_seconds which is drift
321 	 * compensated up to a point (it is guarenteed to remain monotonically
322 	 * increasing).  gd_time_seconds is thus our best uptime guess and
323 	 * suitable for use in the boottime calculation.  It is already taken
324 	 * into account in the basetime calculation above.
325 	 */
326 	boottime.tv_sec = nbt->tv_sec;
327 	ntp_delta = 0;
328 
329 	/*
330 	 * We now have a new basetime, make sure all other cpus have it,
331 	 * then update the index.
332 	 */
333 	cpu_sfence();
334 	basetime_index = ni;
335 
336 	crit_exit();
337 }
338 
339 /*
340  * Each cpu has its own hardclock, but we only increments ticks and softticks
341  * on cpu #0.
342  *
343  * NOTE! systimer! the MP lock might not be held here.  We can only safely
344  * manipulate objects owned by the current cpu.
345  */
346 static void
347 hardclock(systimer_t info, struct intrframe *frame)
348 {
349 	sysclock_t cputicks;
350 	struct proc *p;
351 	struct globaldata *gd = mycpu;
352 
353 	/*
354 	 * Realtime updates are per-cpu.  Note that timer corrections as
355 	 * returned by microtime() and friends make an additional adjustment
356 	 * using a system-wise 'basetime', but the running time is always
357 	 * taken from the per-cpu globaldata area.  Since the same clock
358 	 * is distributing (XXX SMP) to all cpus, the per-cpu timebases
359 	 * stay in synch.
360 	 *
361 	 * Note that we never allow info->time (aka gd->gd_hardclock.time)
362 	 * to reverse index gd_cpuclock_base, but that it is possible for
363 	 * it to temporarily get behind in the seconds if something in the
364 	 * system locks interrupts for a long period of time.  Since periodic
365 	 * timers count events, though everything should resynch again
366 	 * immediately.
367 	 */
368 	cputicks = info->time - gd->gd_cpuclock_base;
369 	if (cputicks >= sys_cputimer->freq) {
370 		++gd->gd_time_seconds;
371 		gd->gd_cpuclock_base += sys_cputimer->freq;
372 	}
373 
374 	/*
375 	 * The system-wide ticks counter and NTP related timedelta/tickdelta
376 	 * adjustments only occur on cpu #0.  NTP adjustments are accomplished
377 	 * by updating basetime.
378 	 */
379 	if (gd->gd_cpuid == 0) {
380 	    struct timespec *nbt;
381 	    struct timespec nts;
382 	    int leap;
383 	    int ni;
384 
385 	    ++ticks;
386 
387 #if 0
388 	    if (tco->tc_poll_pps)
389 		tco->tc_poll_pps(tco);
390 #endif
391 
392 	    /*
393 	     * Calculate the new basetime index.  We are in a critical section
394 	     * on cpu #0 and can safely play with basetime_index.  Start
395 	     * with the current basetime and then make adjustments.
396 	     */
397 	    ni = (basetime_index + 1) & BASETIME_ARYMASK;
398 	    nbt = &basetime[ni];
399 	    *nbt = basetime[basetime_index];
400 
401 	    /*
402 	     * Apply adjtime corrections.  (adjtime() API)
403 	     *
404 	     * adjtime() only runs on cpu #0 so our critical section is
405 	     * sufficient to access these variables.
406 	     */
407 	    if (ntp_delta != 0) {
408 		nbt->tv_nsec += ntp_tick_delta;
409 		ntp_delta -= ntp_tick_delta;
410 		if ((ntp_delta > 0 && ntp_delta < ntp_tick_delta) ||
411 		    (ntp_delta < 0 && ntp_delta > ntp_tick_delta)) {
412 			ntp_tick_delta = ntp_delta;
413  		}
414  	    }
415 
416 	    /*
417 	     * Apply permanent frequency corrections.  (sysctl API)
418 	     */
419 	    if (ntp_tick_permanent != 0) {
420 		ntp_tick_acc += ntp_tick_permanent;
421 		if (ntp_tick_acc >= (1LL << 32)) {
422 		    nbt->tv_nsec += ntp_tick_acc >> 32;
423 		    ntp_tick_acc -= (ntp_tick_acc >> 32) << 32;
424 		} else if (ntp_tick_acc <= -(1LL << 32)) {
425 		    /* Negate ntp_tick_acc to avoid shifting the sign bit. */
426 		    nbt->tv_nsec -= (-ntp_tick_acc) >> 32;
427 		    ntp_tick_acc += ((-ntp_tick_acc) >> 32) << 32;
428 		}
429  	    }
430 
431 	    if (nbt->tv_nsec >= 1000000000) {
432 		    nbt->tv_sec++;
433 		    nbt->tv_nsec -= 1000000000;
434 	    } else if (nbt->tv_nsec < 0) {
435 		    nbt->tv_sec--;
436 		    nbt->tv_nsec += 1000000000;
437 	    }
438 
439 	    /*
440 	     * Another per-tick compensation.  (for ntp_adjtime() API)
441 	     */
442 	    if (nsec_adj != 0) {
443 		nsec_acc += nsec_adj;
444 		if (nsec_acc >= 0x100000000LL) {
445 		    nbt->tv_nsec += nsec_acc >> 32;
446 		    nsec_acc = (nsec_acc & 0xFFFFFFFFLL);
447 		} else if (nsec_acc <= -0x100000000LL) {
448 		    nbt->tv_nsec -= -nsec_acc >> 32;
449 		    nsec_acc = -(-nsec_acc & 0xFFFFFFFFLL);
450 		}
451 		if (nbt->tv_nsec >= 1000000000) {
452 		    nbt->tv_nsec -= 1000000000;
453 		    ++nbt->tv_sec;
454 		} else if (nbt->tv_nsec < 0) {
455 		    nbt->tv_nsec += 1000000000;
456 		    --nbt->tv_sec;
457 		}
458 	    }
459 
460 	    /************************************************************
461 	     *			LEAP SECOND CORRECTION			*
462 	     ************************************************************
463 	     *
464 	     * Taking into account all the corrections made above, figure
465 	     * out the new real time.  If the seconds field has changed
466 	     * then apply any pending leap-second corrections.
467 	     */
468 	    getnanotime_nbt(nbt, &nts);
469 
470 	    if (time_second != nts.tv_sec) {
471 		/*
472 		 * Apply leap second (sysctl API).  Adjust nts for changes
473 		 * so we do not have to call getnanotime_nbt again.
474 		 */
475 		if (ntp_leap_second) {
476 		    if (ntp_leap_second == nts.tv_sec) {
477 			if (ntp_leap_insert) {
478 			    nbt->tv_sec++;
479 			    nts.tv_sec++;
480 			} else {
481 			    nbt->tv_sec--;
482 			    nts.tv_sec--;
483 			}
484 			ntp_leap_second--;
485 		    }
486 		}
487 
488 		/*
489 		 * Apply leap second (ntp_adjtime() API), calculate a new
490 		 * nsec_adj field.  ntp_update_second() returns nsec_adj
491 		 * as a per-second value but we need it as a per-tick value.
492 		 */
493 		leap = ntp_update_second(time_second, &nsec_adj);
494 		nsec_adj /= hz;
495 		nbt->tv_sec += leap;
496 		nts.tv_sec += leap;
497 
498 		/*
499 		 * Update the time_second 'approximate time' global.
500 		 */
501 		time_second = nts.tv_sec;
502 	    }
503 
504 	    /*
505 	     * Finally, our new basetime is ready to go live!
506 	     */
507 	    cpu_sfence();
508 	    basetime_index = ni;
509 
510 	    /*
511 	     * Figure out how badly the system is starved for memory
512 	     */
513 	    vm_fault_ratecheck();
514 	}
515 
516 	/*
517 	 * softticks are handled for all cpus
518 	 */
519 	hardclock_softtick(gd);
520 
521 	/*
522 	 * The LWKT scheduler will generally allow the current process to
523 	 * return to user mode even if there are other runnable LWKT threads
524 	 * running in kernel mode on behalf of a user process.  This will
525 	 * ensure that those other threads have an opportunity to run in
526 	 * fairly short order (but not instantly).
527 	 */
528 	need_lwkt_resched();
529 
530 	/*
531 	 * ITimer handling is per-tick, per-cpu.  I don't think ksignal()
532 	 * is mpsafe on curproc, so XXX get the mplock.
533 	 */
534 	if ((p = curproc) != NULL && try_mplock()) {
535 		if (frame && CLKF_USERMODE(frame) &&
536 		    timevalisset(&p->p_timer[ITIMER_VIRTUAL].it_value) &&
537 		    itimerdecr(&p->p_timer[ITIMER_VIRTUAL], tick) == 0)
538 			ksignal(p, SIGVTALRM);
539 		if (timevalisset(&p->p_timer[ITIMER_PROF].it_value) &&
540 		    itimerdecr(&p->p_timer[ITIMER_PROF], tick) == 0)
541 			ksignal(p, SIGPROF);
542 		rel_mplock();
543 	}
544 	setdelayed();
545 }
546 
547 /*
548  * The statistics clock typically runs at a 125Hz rate, and is intended
549  * to be frequency offset from the hardclock (typ 100Hz).  It is per-cpu.
550  *
551  * NOTE! systimer! the MP lock might not be held here.  We can only safely
552  * manipulate objects owned by the current cpu.
553  *
554  * The stats clock is responsible for grabbing a profiling sample.
555  * Most of the statistics are only used by user-level statistics programs.
556  * The main exceptions are p->p_uticks, p->p_sticks, p->p_iticks, and
557  * p->p_estcpu.
558  *
559  * Like the other clocks, the stat clock is called from what is effectively
560  * a fast interrupt, so the context should be the thread/process that got
561  * interrupted.
562  */
563 static void
564 statclock(systimer_t info, struct intrframe *frame)
565 {
566 #ifdef GPROF
567 	struct gmonparam *g;
568 	int i;
569 #endif
570 	thread_t td;
571 	struct proc *p;
572 	int bump;
573 	struct timeval tv;
574 	struct timeval *stv;
575 
576 	/*
577 	 * How big was our timeslice relative to the last time?
578 	 */
579 	microuptime(&tv);	/* mpsafe */
580 	stv = &mycpu->gd_stattv;
581 	if (stv->tv_sec == 0) {
582 	    bump = 1;
583 	} else {
584 	    bump = tv.tv_usec - stv->tv_usec +
585 		(tv.tv_sec - stv->tv_sec) * 1000000;
586 	    if (bump < 0)
587 		bump = 0;
588 	    if (bump > 1000000)
589 		bump = 1000000;
590 	}
591 	*stv = tv;
592 
593 	td = curthread;
594 	p = td->td_proc;
595 
596 	if (frame && CLKF_USERMODE(frame)) {
597 		/*
598 		 * Came from userland, handle user time and deal with
599 		 * possible process.
600 		 */
601 		if (p && (p->p_flag & P_PROFIL))
602 			addupc_intr(p, CLKF_PC(frame), 1);
603 		td->td_uticks += bump;
604 
605 		/*
606 		 * Charge the time as appropriate
607 		 */
608 		if (p && p->p_nice > NZERO)
609 			cpu_time.cp_nice += bump;
610 		else
611 			cpu_time.cp_user += bump;
612 	} else {
613 #ifdef GPROF
614 		/*
615 		 * Kernel statistics are just like addupc_intr, only easier.
616 		 */
617 		g = &_gmonparam;
618 		if (g->state == GMON_PROF_ON && frame) {
619 			i = CLKF_PC(frame) - g->lowpc;
620 			if (i < g->textsize) {
621 				i /= HISTFRACTION * sizeof(*g->kcount);
622 				g->kcount[i]++;
623 			}
624 		}
625 #endif
626 		/*
627 		 * Came from kernel mode, so we were:
628 		 * - handling an interrupt,
629 		 * - doing syscall or trap work on behalf of the current
630 		 *   user process, or
631 		 * - spinning in the idle loop.
632 		 * Whichever it is, charge the time as appropriate.
633 		 * Note that we charge interrupts to the current process,
634 		 * regardless of whether they are ``for'' that process,
635 		 * so that we know how much of its real time was spent
636 		 * in ``non-process'' (i.e., interrupt) work.
637 		 *
638 		 * XXX assume system if frame is NULL.  A NULL frame
639 		 * can occur if ipi processing is done from a crit_exit().
640 		 */
641 		if (frame && CLKF_INTR(frame))
642 			td->td_iticks += bump;
643 		else
644 			td->td_sticks += bump;
645 
646 		if (frame && CLKF_INTR(frame)) {
647 #ifdef DEBUG_PCTRACK
648 			do_pctrack(frame, PCTRACK_INT);
649 #endif
650 			cpu_time.cp_intr += bump;
651 		} else {
652 			if (td == &mycpu->gd_idlethread) {
653 				cpu_time.cp_idle += bump;
654 			} else {
655 #ifdef DEBUG_PCTRACK
656 				if (frame)
657 					do_pctrack(frame, PCTRACK_SYS);
658 #endif
659 				cpu_time.cp_sys += bump;
660 			}
661 		}
662 	}
663 }
664 
665 #ifdef DEBUG_PCTRACK
666 /*
667  * Sample the PC when in the kernel or in an interrupt.  User code can
668  * retrieve the information and generate a histogram or other output.
669  */
670 
671 static void
672 do_pctrack(struct intrframe *frame, int which)
673 {
674 	struct kinfo_pctrack *pctrack;
675 
676 	pctrack = &cputime_pctrack[mycpu->gd_cpuid][which];
677 	pctrack->pc_array[pctrack->pc_index & PCTRACK_ARYMASK] =
678 		(void *)CLKF_PC(frame);
679 	++pctrack->pc_index;
680 }
681 
682 static int
683 sysctl_pctrack(SYSCTL_HANDLER_ARGS)
684 {
685 	struct kinfo_pcheader head;
686 	int error;
687 	int cpu;
688 	int ntrack;
689 
690 	head.pc_ntrack = PCTRACK_SIZE;
691 	head.pc_arysize = PCTRACK_ARYSIZE;
692 
693 	if ((error = SYSCTL_OUT(req, &head, sizeof(head))) != 0)
694 		return (error);
695 
696 	for (cpu = 0; cpu < ncpus; ++cpu) {
697 		for (ntrack = 0; ntrack < PCTRACK_SIZE; ++ntrack) {
698 			error = SYSCTL_OUT(req, &cputime_pctrack[cpu][ntrack],
699 					   sizeof(struct kinfo_pctrack));
700 			if (error)
701 				break;
702 		}
703 		if (error)
704 			break;
705 	}
706 	return (error);
707 }
708 SYSCTL_PROC(_kern, OID_AUTO, pctrack, (CTLTYPE_OPAQUE|CTLFLAG_RD), 0, 0,
709 	sysctl_pctrack, "S,kinfo_pcheader", "CPU PC tracking");
710 
711 #endif
712 
713 /*
714  * The scheduler clock typically runs at a 50Hz rate.  NOTE! systimer,
715  * the MP lock might not be held.  We can safely manipulate parts of curproc
716  * but that's about it.
717  *
718  * Each cpu has its own scheduler clock.
719  */
720 static void
721 schedclock(systimer_t info, struct intrframe *frame)
722 {
723 	struct lwp *lp;
724 	struct rusage *ru;
725 	struct vmspace *vm;
726 	long rss;
727 
728 	if ((lp = lwkt_preempted_proc()) != NULL) {
729 		/*
730 		 * Account for cpu time used and hit the scheduler.  Note
731 		 * that this call MUST BE MP SAFE, and the BGL IS NOT HELD
732 		 * HERE.
733 		 */
734 		++lp->lwp_cpticks;
735 		lp->lwp_proc->p_usched->schedulerclock(lp, info->periodic,
736 						       info->time);
737 	}
738 	if ((lp = curthread->td_lwp) != NULL) {
739 		/*
740 		 * Update resource usage integrals and maximums.
741 		 */
742 		if ((ru = &lp->lwp_proc->p_ru) &&
743 		    (vm = lp->lwp_proc->p_vmspace) != NULL) {
744 			ru->ru_ixrss += pgtok(vm->vm_tsize);
745 			ru->ru_idrss += pgtok(vm->vm_dsize);
746 			ru->ru_isrss += pgtok(vm->vm_ssize);
747 			rss = pgtok(vmspace_resident_count(vm));
748 			if (ru->ru_maxrss < rss)
749 				ru->ru_maxrss = rss;
750 		}
751 	}
752 }
753 
754 /*
755  * Compute number of ticks for the specified amount of time.  The
756  * return value is intended to be used in a clock interrupt timed
757  * operation and guarenteed to meet or exceed the requested time.
758  * If the representation overflows, return INT_MAX.  The minimum return
759  * value is 1 ticks and the function will average the calculation up.
760  * If any value greater then 0 microseconds is supplied, a value
761  * of at least 2 will be returned to ensure that a near-term clock
762  * interrupt does not cause the timeout to occur (degenerately) early.
763  *
764  * Note that limit checks must take into account microseconds, which is
765  * done simply by using the smaller signed long maximum instead of
766  * the unsigned long maximum.
767  *
768  * If ints have 32 bits, then the maximum value for any timeout in
769  * 10ms ticks is 248 days.
770  */
771 int
772 tvtohz_high(struct timeval *tv)
773 {
774 	int ticks;
775 	long sec, usec;
776 
777 	sec = tv->tv_sec;
778 	usec = tv->tv_usec;
779 	if (usec < 0) {
780 		sec--;
781 		usec += 1000000;
782 	}
783 	if (sec < 0) {
784 #ifdef DIAGNOSTIC
785 		if (usec > 0) {
786 			sec++;
787 			usec -= 1000000;
788 		}
789 		kprintf("tvtohz_high: negative time difference %ld sec %ld usec\n",
790 		       sec, usec);
791 #endif
792 		ticks = 1;
793 	} else if (sec <= INT_MAX / hz) {
794 		ticks = (int)(sec * hz +
795 			    ((u_long)usec + (tick - 1)) / tick) + 1;
796 	} else {
797 		ticks = INT_MAX;
798 	}
799 	return (ticks);
800 }
801 
802 /*
803  * Compute number of ticks for the specified amount of time, erroring on
804  * the side of it being too low to ensure that sleeping the returned number
805  * of ticks will not result in a late return.
806  *
807  * The supplied timeval may not be negative and should be normalized.  A
808  * return value of 0 is possible if the timeval converts to less then
809  * 1 tick.
810  *
811  * If ints have 32 bits, then the maximum value for any timeout in
812  * 10ms ticks is 248 days.
813  */
814 int
815 tvtohz_low(struct timeval *tv)
816 {
817 	int ticks;
818 	long sec;
819 
820 	sec = tv->tv_sec;
821 	if (sec <= INT_MAX / hz)
822 		ticks = (int)(sec * hz + (u_long)tv->tv_usec / tick);
823 	else
824 		ticks = INT_MAX;
825 	return (ticks);
826 }
827 
828 
829 /*
830  * Start profiling on a process.
831  *
832  * Kernel profiling passes proc0 which never exits and hence
833  * keeps the profile clock running constantly.
834  */
835 void
836 startprofclock(struct proc *p)
837 {
838 	if ((p->p_flag & P_PROFIL) == 0) {
839 		p->p_flag |= P_PROFIL;
840 #if 0	/* XXX */
841 		if (++profprocs == 1 && stathz != 0) {
842 			crit_enter();
843 			psdiv = psratio;
844 			setstatclockrate(profhz);
845 			crit_exit();
846 		}
847 #endif
848 	}
849 }
850 
851 /*
852  * Stop profiling on a process.
853  */
854 void
855 stopprofclock(struct proc *p)
856 {
857 	if (p->p_flag & P_PROFIL) {
858 		p->p_flag &= ~P_PROFIL;
859 #if 0	/* XXX */
860 		if (--profprocs == 0 && stathz != 0) {
861 			crit_enter();
862 			psdiv = 1;
863 			setstatclockrate(stathz);
864 			crit_exit();
865 		}
866 #endif
867 	}
868 }
869 
870 /*
871  * Return information about system clocks.
872  */
873 static int
874 sysctl_kern_clockrate(SYSCTL_HANDLER_ARGS)
875 {
876 	struct kinfo_clockinfo clkinfo;
877 	/*
878 	 * Construct clockinfo structure.
879 	 */
880 	clkinfo.ci_hz = hz;
881 	clkinfo.ci_tick = tick;
882 	clkinfo.ci_tickadj = ntp_default_tick_delta / 1000;
883 	clkinfo.ci_profhz = profhz;
884 	clkinfo.ci_stathz = stathz ? stathz : hz;
885 	return (sysctl_handle_opaque(oidp, &clkinfo, sizeof clkinfo, req));
886 }
887 
888 SYSCTL_PROC(_kern, KERN_CLOCKRATE, clockrate, CTLTYPE_STRUCT|CTLFLAG_RD,
889 	0, 0, sysctl_kern_clockrate, "S,clockinfo","");
890 
891 /*
892  * We have eight functions for looking at the clock, four for
893  * microseconds and four for nanoseconds.  For each there is fast
894  * but less precise version "get{nano|micro}[up]time" which will
895  * return a time which is up to 1/HZ previous to the call, whereas
896  * the raw version "{nano|micro}[up]time" will return a timestamp
897  * which is as precise as possible.  The "up" variants return the
898  * time relative to system boot, these are well suited for time
899  * interval measurements.
900  *
901  * Each cpu independantly maintains the current time of day, so all
902  * we need to do to protect ourselves from changes is to do a loop
903  * check on the seconds field changing out from under us.
904  *
905  * The system timer maintains a 32 bit count and due to various issues
906  * it is possible for the calculated delta to occassionally exceed
907  * sys_cputimer->freq.  If this occurs the sys_cputimer->freq64_nsec
908  * multiplication can easily overflow, so we deal with the case.  For
909  * uniformity we deal with the case in the usec case too.
910  */
911 void
912 getmicrouptime(struct timeval *tvp)
913 {
914 	struct globaldata *gd = mycpu;
915 	sysclock_t delta;
916 
917 	do {
918 		tvp->tv_sec = gd->gd_time_seconds;
919 		delta = gd->gd_hardclock.time - gd->gd_cpuclock_base;
920 	} while (tvp->tv_sec != gd->gd_time_seconds);
921 
922 	if (delta >= sys_cputimer->freq) {
923 		tvp->tv_sec += delta / sys_cputimer->freq;
924 		delta %= sys_cputimer->freq;
925 	}
926 	tvp->tv_usec = (sys_cputimer->freq64_usec * delta) >> 32;
927 	if (tvp->tv_usec >= 1000000) {
928 		tvp->tv_usec -= 1000000;
929 		++tvp->tv_sec;
930 	}
931 }
932 
933 void
934 getnanouptime(struct timespec *tsp)
935 {
936 	struct globaldata *gd = mycpu;
937 	sysclock_t delta;
938 
939 	do {
940 		tsp->tv_sec = gd->gd_time_seconds;
941 		delta = gd->gd_hardclock.time - gd->gd_cpuclock_base;
942 	} while (tsp->tv_sec != gd->gd_time_seconds);
943 
944 	if (delta >= sys_cputimer->freq) {
945 		tsp->tv_sec += delta / sys_cputimer->freq;
946 		delta %= sys_cputimer->freq;
947 	}
948 	tsp->tv_nsec = (sys_cputimer->freq64_nsec * delta) >> 32;
949 }
950 
951 void
952 microuptime(struct timeval *tvp)
953 {
954 	struct globaldata *gd = mycpu;
955 	sysclock_t delta;
956 
957 	do {
958 		tvp->tv_sec = gd->gd_time_seconds;
959 		delta = sys_cputimer->count() - gd->gd_cpuclock_base;
960 	} while (tvp->tv_sec != gd->gd_time_seconds);
961 
962 	if (delta >= sys_cputimer->freq) {
963 		tvp->tv_sec += delta / sys_cputimer->freq;
964 		delta %= sys_cputimer->freq;
965 	}
966 	tvp->tv_usec = (sys_cputimer->freq64_usec * delta) >> 32;
967 }
968 
969 void
970 nanouptime(struct timespec *tsp)
971 {
972 	struct globaldata *gd = mycpu;
973 	sysclock_t delta;
974 
975 	do {
976 		tsp->tv_sec = gd->gd_time_seconds;
977 		delta = sys_cputimer->count() - gd->gd_cpuclock_base;
978 	} while (tsp->tv_sec != gd->gd_time_seconds);
979 
980 	if (delta >= sys_cputimer->freq) {
981 		tsp->tv_sec += delta / sys_cputimer->freq;
982 		delta %= sys_cputimer->freq;
983 	}
984 	tsp->tv_nsec = (sys_cputimer->freq64_nsec * delta) >> 32;
985 }
986 
987 /*
988  * realtime routines
989  */
990 
991 void
992 getmicrotime(struct timeval *tvp)
993 {
994 	struct globaldata *gd = mycpu;
995 	struct timespec *bt;
996 	sysclock_t delta;
997 
998 	do {
999 		tvp->tv_sec = gd->gd_time_seconds;
1000 		delta = gd->gd_hardclock.time - gd->gd_cpuclock_base;
1001 	} while (tvp->tv_sec != gd->gd_time_seconds);
1002 
1003 	if (delta >= sys_cputimer->freq) {
1004 		tvp->tv_sec += delta / sys_cputimer->freq;
1005 		delta %= sys_cputimer->freq;
1006 	}
1007 	tvp->tv_usec = (sys_cputimer->freq64_usec * delta) >> 32;
1008 
1009 	bt = &basetime[basetime_index];
1010 	tvp->tv_sec += bt->tv_sec;
1011 	tvp->tv_usec += bt->tv_nsec / 1000;
1012 	while (tvp->tv_usec >= 1000000) {
1013 		tvp->tv_usec -= 1000000;
1014 		++tvp->tv_sec;
1015 	}
1016 }
1017 
1018 void
1019 getnanotime(struct timespec *tsp)
1020 {
1021 	struct globaldata *gd = mycpu;
1022 	struct timespec *bt;
1023 	sysclock_t delta;
1024 
1025 	do {
1026 		tsp->tv_sec = gd->gd_time_seconds;
1027 		delta = gd->gd_hardclock.time - gd->gd_cpuclock_base;
1028 	} while (tsp->tv_sec != gd->gd_time_seconds);
1029 
1030 	if (delta >= sys_cputimer->freq) {
1031 		tsp->tv_sec += delta / sys_cputimer->freq;
1032 		delta %= sys_cputimer->freq;
1033 	}
1034 	tsp->tv_nsec = (sys_cputimer->freq64_nsec * delta) >> 32;
1035 
1036 	bt = &basetime[basetime_index];
1037 	tsp->tv_sec += bt->tv_sec;
1038 	tsp->tv_nsec += bt->tv_nsec;
1039 	while (tsp->tv_nsec >= 1000000000) {
1040 		tsp->tv_nsec -= 1000000000;
1041 		++tsp->tv_sec;
1042 	}
1043 }
1044 
1045 static void
1046 getnanotime_nbt(struct timespec *nbt, struct timespec *tsp)
1047 {
1048 	struct globaldata *gd = mycpu;
1049 	sysclock_t delta;
1050 
1051 	do {
1052 		tsp->tv_sec = gd->gd_time_seconds;
1053 		delta = gd->gd_hardclock.time - gd->gd_cpuclock_base;
1054 	} while (tsp->tv_sec != gd->gd_time_seconds);
1055 
1056 	if (delta >= sys_cputimer->freq) {
1057 		tsp->tv_sec += delta / sys_cputimer->freq;
1058 		delta %= sys_cputimer->freq;
1059 	}
1060 	tsp->tv_nsec = (sys_cputimer->freq64_nsec * delta) >> 32;
1061 
1062 	tsp->tv_sec += nbt->tv_sec;
1063 	tsp->tv_nsec += nbt->tv_nsec;
1064 	while (tsp->tv_nsec >= 1000000000) {
1065 		tsp->tv_nsec -= 1000000000;
1066 		++tsp->tv_sec;
1067 	}
1068 }
1069 
1070 
1071 void
1072 microtime(struct timeval *tvp)
1073 {
1074 	struct globaldata *gd = mycpu;
1075 	struct timespec *bt;
1076 	sysclock_t delta;
1077 
1078 	do {
1079 		tvp->tv_sec = gd->gd_time_seconds;
1080 		delta = sys_cputimer->count() - gd->gd_cpuclock_base;
1081 	} while (tvp->tv_sec != gd->gd_time_seconds);
1082 
1083 	if (delta >= sys_cputimer->freq) {
1084 		tvp->tv_sec += delta / sys_cputimer->freq;
1085 		delta %= sys_cputimer->freq;
1086 	}
1087 	tvp->tv_usec = (sys_cputimer->freq64_usec * delta) >> 32;
1088 
1089 	bt = &basetime[basetime_index];
1090 	tvp->tv_sec += bt->tv_sec;
1091 	tvp->tv_usec += bt->tv_nsec / 1000;
1092 	while (tvp->tv_usec >= 1000000) {
1093 		tvp->tv_usec -= 1000000;
1094 		++tvp->tv_sec;
1095 	}
1096 }
1097 
1098 void
1099 nanotime(struct timespec *tsp)
1100 {
1101 	struct globaldata *gd = mycpu;
1102 	struct timespec *bt;
1103 	sysclock_t delta;
1104 
1105 	do {
1106 		tsp->tv_sec = gd->gd_time_seconds;
1107 		delta = sys_cputimer->count() - gd->gd_cpuclock_base;
1108 	} while (tsp->tv_sec != gd->gd_time_seconds);
1109 
1110 	if (delta >= sys_cputimer->freq) {
1111 		tsp->tv_sec += delta / sys_cputimer->freq;
1112 		delta %= sys_cputimer->freq;
1113 	}
1114 	tsp->tv_nsec = (sys_cputimer->freq64_nsec * delta) >> 32;
1115 
1116 	bt = &basetime[basetime_index];
1117 	tsp->tv_sec += bt->tv_sec;
1118 	tsp->tv_nsec += bt->tv_nsec;
1119 	while (tsp->tv_nsec >= 1000000000) {
1120 		tsp->tv_nsec -= 1000000000;
1121 		++tsp->tv_sec;
1122 	}
1123 }
1124 
1125 /*
1126  * note: this is not exactly synchronized with real time.  To do that we
1127  * would have to do what microtime does and check for a nanoseconds overflow.
1128  */
1129 time_t
1130 get_approximate_time_t(void)
1131 {
1132 	struct globaldata *gd = mycpu;
1133 	struct timespec *bt;
1134 
1135 	bt = &basetime[basetime_index];
1136 	return(gd->gd_time_seconds + bt->tv_sec);
1137 }
1138 
1139 int
1140 pps_ioctl(u_long cmd, caddr_t data, struct pps_state *pps)
1141 {
1142 	pps_params_t *app;
1143 	struct pps_fetch_args *fapi;
1144 #ifdef PPS_SYNC
1145 	struct pps_kcbind_args *kapi;
1146 #endif
1147 
1148 	switch (cmd) {
1149 	case PPS_IOC_CREATE:
1150 		return (0);
1151 	case PPS_IOC_DESTROY:
1152 		return (0);
1153 	case PPS_IOC_SETPARAMS:
1154 		app = (pps_params_t *)data;
1155 		if (app->mode & ~pps->ppscap)
1156 			return (EINVAL);
1157 		pps->ppsparam = *app;
1158 		return (0);
1159 	case PPS_IOC_GETPARAMS:
1160 		app = (pps_params_t *)data;
1161 		*app = pps->ppsparam;
1162 		app->api_version = PPS_API_VERS_1;
1163 		return (0);
1164 	case PPS_IOC_GETCAP:
1165 		*(int*)data = pps->ppscap;
1166 		return (0);
1167 	case PPS_IOC_FETCH:
1168 		fapi = (struct pps_fetch_args *)data;
1169 		if (fapi->tsformat && fapi->tsformat != PPS_TSFMT_TSPEC)
1170 			return (EINVAL);
1171 		if (fapi->timeout.tv_sec || fapi->timeout.tv_nsec)
1172 			return (EOPNOTSUPP);
1173 		pps->ppsinfo.current_mode = pps->ppsparam.mode;
1174 		fapi->pps_info_buf = pps->ppsinfo;
1175 		return (0);
1176 	case PPS_IOC_KCBIND:
1177 #ifdef PPS_SYNC
1178 		kapi = (struct pps_kcbind_args *)data;
1179 		/* XXX Only root should be able to do this */
1180 		if (kapi->tsformat && kapi->tsformat != PPS_TSFMT_TSPEC)
1181 			return (EINVAL);
1182 		if (kapi->kernel_consumer != PPS_KC_HARDPPS)
1183 			return (EINVAL);
1184 		if (kapi->edge & ~pps->ppscap)
1185 			return (EINVAL);
1186 		pps->kcmode = kapi->edge;
1187 		return (0);
1188 #else
1189 		return (EOPNOTSUPP);
1190 #endif
1191 	default:
1192 		return (ENOTTY);
1193 	}
1194 }
1195 
1196 void
1197 pps_init(struct pps_state *pps)
1198 {
1199 	pps->ppscap |= PPS_TSFMT_TSPEC;
1200 	if (pps->ppscap & PPS_CAPTUREASSERT)
1201 		pps->ppscap |= PPS_OFFSETASSERT;
1202 	if (pps->ppscap & PPS_CAPTURECLEAR)
1203 		pps->ppscap |= PPS_OFFSETCLEAR;
1204 }
1205 
1206 void
1207 pps_event(struct pps_state *pps, sysclock_t count, int event)
1208 {
1209 	struct globaldata *gd;
1210 	struct timespec *tsp;
1211 	struct timespec *osp;
1212 	struct timespec *bt;
1213 	struct timespec ts;
1214 	sysclock_t *pcount;
1215 #ifdef PPS_SYNC
1216 	sysclock_t tcount;
1217 #endif
1218 	sysclock_t delta;
1219 	pps_seq_t *pseq;
1220 	int foff;
1221 	int fhard;
1222 
1223 	gd = mycpu;
1224 
1225 	/* Things would be easier with arrays... */
1226 	if (event == PPS_CAPTUREASSERT) {
1227 		tsp = &pps->ppsinfo.assert_timestamp;
1228 		osp = &pps->ppsparam.assert_offset;
1229 		foff = pps->ppsparam.mode & PPS_OFFSETASSERT;
1230 		fhard = pps->kcmode & PPS_CAPTUREASSERT;
1231 		pcount = &pps->ppscount[0];
1232 		pseq = &pps->ppsinfo.assert_sequence;
1233 	} else {
1234 		tsp = &pps->ppsinfo.clear_timestamp;
1235 		osp = &pps->ppsparam.clear_offset;
1236 		foff = pps->ppsparam.mode & PPS_OFFSETCLEAR;
1237 		fhard = pps->kcmode & PPS_CAPTURECLEAR;
1238 		pcount = &pps->ppscount[1];
1239 		pseq = &pps->ppsinfo.clear_sequence;
1240 	}
1241 
1242 	/* Nothing really happened */
1243 	if (*pcount == count)
1244 		return;
1245 
1246 	*pcount = count;
1247 
1248 	do {
1249 		ts.tv_sec = gd->gd_time_seconds;
1250 		delta = count - gd->gd_cpuclock_base;
1251 	} while (ts.tv_sec != gd->gd_time_seconds);
1252 
1253 	if (delta >= sys_cputimer->freq) {
1254 		ts.tv_sec += delta / sys_cputimer->freq;
1255 		delta %= sys_cputimer->freq;
1256 	}
1257 	ts.tv_nsec = (sys_cputimer->freq64_nsec * delta) >> 32;
1258 	bt = &basetime[basetime_index];
1259 	ts.tv_sec += bt->tv_sec;
1260 	ts.tv_nsec += bt->tv_nsec;
1261 	while (ts.tv_nsec >= 1000000000) {
1262 		ts.tv_nsec -= 1000000000;
1263 		++ts.tv_sec;
1264 	}
1265 
1266 	(*pseq)++;
1267 	*tsp = ts;
1268 
1269 	if (foff) {
1270 		timespecadd(tsp, osp);
1271 		if (tsp->tv_nsec < 0) {
1272 			tsp->tv_nsec += 1000000000;
1273 			tsp->tv_sec -= 1;
1274 		}
1275 	}
1276 #ifdef PPS_SYNC
1277 	if (fhard) {
1278 		/* magic, at its best... */
1279 		tcount = count - pps->ppscount[2];
1280 		pps->ppscount[2] = count;
1281 		if (tcount >= sys_cputimer->freq) {
1282 			delta = (1000000000 * (tcount / sys_cputimer->freq) +
1283 				 sys_cputimer->freq64_nsec *
1284 				 (tcount % sys_cputimer->freq)) >> 32;
1285 		} else {
1286 			delta = (sys_cputimer->freq64_nsec * tcount) >> 32;
1287 		}
1288 		hardpps(tsp, delta);
1289 	}
1290 #endif
1291 }
1292 
1293