xref: /dragonfly/sys/kern/kern_clock.c (revision 52f9f0d9)
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/resource.h>
89 #include <sys/resourcevar.h>
90 #include <sys/signalvar.h>
91 #include <sys/timex.h>
92 #include <sys/timepps.h>
93 #include <vm/vm.h>
94 #include <sys/lock.h>
95 #include <vm/pmap.h>
96 #include <vm/vm_map.h>
97 #include <vm/vm_extern.h>
98 #include <sys/sysctl.h>
99 
100 #include <sys/thread2.h>
101 
102 #include <machine/cpu.h>
103 #include <machine/limits.h>
104 #include <machine/smp.h>
105 #include <machine/cpufunc.h>
106 #include <machine/specialreg.h>
107 #include <machine/clock.h>
108 
109 #ifdef GPROF
110 #include <sys/gmon.h>
111 #endif
112 
113 #ifdef DEVICE_POLLING
114 extern void init_device_poll_pcpu(int);
115 #endif
116 
117 #ifdef IFPOLL_ENABLE
118 extern void ifpoll_init_pcpu(int);
119 #endif
120 
121 #ifdef DEBUG_PCTRACK
122 static void do_pctrack(struct intrframe *frame, int which);
123 #endif
124 
125 static void initclocks (void *dummy);
126 SYSINIT(clocks, SI_BOOT2_CLOCKS, SI_ORDER_FIRST, initclocks, NULL)
127 
128 /*
129  * Some of these don't belong here, but it's easiest to concentrate them.
130  * Note that cpu_time counts in microseconds, but most userland programs
131  * just compare relative times against the total by delta.
132  */
133 struct kinfo_cputime cputime_percpu[MAXCPU];
134 #ifdef DEBUG_PCTRACK
135 struct kinfo_pcheader cputime_pcheader = { PCTRACK_SIZE, PCTRACK_ARYSIZE };
136 struct kinfo_pctrack cputime_pctrack[MAXCPU][PCTRACK_SIZE];
137 #endif
138 
139 #ifdef SMP
140 static int
141 sysctl_cputime(SYSCTL_HANDLER_ARGS)
142 {
143 	int cpu, error = 0;
144 	size_t size = sizeof(struct kinfo_cputime);
145 
146 	for (cpu = 0; cpu < ncpus; ++cpu) {
147 		if ((error = SYSCTL_OUT(req, &cputime_percpu[cpu], size)))
148 			break;
149 	}
150 
151 	return (error);
152 }
153 SYSCTL_PROC(_kern, OID_AUTO, cputime, (CTLTYPE_OPAQUE|CTLFLAG_RD), 0, 0,
154 	sysctl_cputime, "S,kinfo_cputime", "CPU time statistics");
155 #else
156 SYSCTL_STRUCT(_kern, OID_AUTO, cputime, CTLFLAG_RD, &cpu_time, kinfo_cputime,
157     "CPU time statistics");
158 #endif
159 
160 static int
161 sysctl_cp_time(SYSCTL_HANDLER_ARGS)
162 {
163 	long cpu_states[5] = {0};
164 	int cpu, error = 0;
165 	size_t size = sizeof(cpu_states);
166 
167 	for (cpu = 0; cpu < ncpus; ++cpu) {
168 		cpu_states[CP_USER] += cputime_percpu[cpu].cp_user;
169 		cpu_states[CP_NICE] += cputime_percpu[cpu].cp_nice;
170 		cpu_states[CP_SYS] += cputime_percpu[cpu].cp_sys;
171 		cpu_states[CP_INTR] += cputime_percpu[cpu].cp_intr;
172 		cpu_states[CP_IDLE] += cputime_percpu[cpu].cp_idle;
173 	}
174 
175 	error = SYSCTL_OUT(req, cpu_states, size);
176 
177 	return (error);
178 }
179 
180 SYSCTL_PROC(_kern, OID_AUTO, cp_time, (CTLTYPE_LONG|CTLFLAG_RD), 0, 0,
181 	sysctl_cp_time, "LU", "CPU time statistics");
182 
183 /*
184  * boottime is used to calculate the 'real' uptime.  Do not confuse this with
185  * microuptime().  microtime() is not drift compensated.  The real uptime
186  * with compensation is nanotime() - bootime.  boottime is recalculated
187  * whenever the real time is set based on the compensated elapsed time
188  * in seconds (gd->gd_time_seconds).
189  *
190  * The gd_time_seconds and gd_cpuclock_base fields remain fairly monotonic.
191  * Slight adjustments to gd_cpuclock_base are made to phase-lock it to
192  * the real time.
193  */
194 struct timespec boottime;	/* boot time (realtime) for reference only */
195 time_t time_second;		/* read-only 'passive' uptime in seconds */
196 
197 /*
198  * basetime is used to calculate the compensated real time of day.  The
199  * basetime can be modified on a per-tick basis by the adjtime(),
200  * ntp_adjtime(), and sysctl-based time correction APIs.
201  *
202  * Note that frequency corrections can also be made by adjusting
203  * gd_cpuclock_base.
204  *
205  * basetime is a tail-chasing FIFO, updated only by cpu #0.  The FIFO is
206  * used on both SMP and UP systems to avoid MP races between cpu's and
207  * interrupt races on UP systems.
208  */
209 #define BASETIME_ARYSIZE	16
210 #define BASETIME_ARYMASK	(BASETIME_ARYSIZE - 1)
211 static struct timespec basetime[BASETIME_ARYSIZE];
212 static volatile int basetime_index;
213 
214 static int
215 sysctl_get_basetime(SYSCTL_HANDLER_ARGS)
216 {
217 	struct timespec *bt;
218 	int error;
219 	int index;
220 
221 	/*
222 	 * Because basetime data and index may be updated by another cpu,
223 	 * a load fence is required to ensure that the data we read has
224 	 * not been speculatively read relative to a possibly updated index.
225 	 */
226 	index = basetime_index;
227 	cpu_lfence();
228 	bt = &basetime[index];
229 	error = SYSCTL_OUT(req, bt, sizeof(*bt));
230 	return (error);
231 }
232 
233 SYSCTL_STRUCT(_kern, KERN_BOOTTIME, boottime, CTLFLAG_RD,
234     &boottime, timespec, "System boottime");
235 SYSCTL_PROC(_kern, OID_AUTO, basetime, CTLTYPE_STRUCT|CTLFLAG_RD, 0, 0,
236     sysctl_get_basetime, "S,timespec", "System basetime");
237 
238 static void hardclock(systimer_t info, int, struct intrframe *frame);
239 static void statclock(systimer_t info, int, struct intrframe *frame);
240 static void schedclock(systimer_t info, int, struct intrframe *frame);
241 static void getnanotime_nbt(struct timespec *nbt, struct timespec *tsp);
242 
243 int	ticks;			/* system master ticks at hz */
244 int	clocks_running;		/* tsleep/timeout clocks operational */
245 int64_t	nsec_adj;		/* ntpd per-tick adjustment in nsec << 32 */
246 int64_t	nsec_acc;		/* accumulator */
247 
248 /* NTPD time correction fields */
249 int64_t	ntp_tick_permanent;	/* per-tick adjustment in nsec << 32 */
250 int64_t	ntp_tick_acc;		/* accumulator for per-tick adjustment */
251 int64_t	ntp_delta;		/* one-time correction in nsec */
252 int64_t ntp_big_delta = 1000000000;
253 int32_t	ntp_tick_delta;		/* current adjustment rate */
254 int32_t	ntp_default_tick_delta;	/* adjustment rate for ntp_delta */
255 time_t	ntp_leap_second;	/* time of next leap second */
256 int	ntp_leap_insert;	/* whether to insert or remove a second */
257 
258 /*
259  * Finish initializing clock frequencies and start all clocks running.
260  */
261 /* ARGSUSED*/
262 static void
263 initclocks(void *dummy)
264 {
265 	/*psratio = profhz / stathz;*/
266 	initclocks_pcpu();
267 	clocks_running = 1;
268 }
269 
270 /*
271  * Called on a per-cpu basis
272  */
273 void
274 initclocks_pcpu(void)
275 {
276 	struct globaldata *gd = mycpu;
277 
278 	crit_enter();
279 	if (gd->gd_cpuid == 0) {
280 	    gd->gd_time_seconds = 1;
281 	    gd->gd_cpuclock_base = sys_cputimer->count();
282 	} else {
283 	    /* XXX */
284 	    gd->gd_time_seconds = globaldata_find(0)->gd_time_seconds;
285 	    gd->gd_cpuclock_base = globaldata_find(0)->gd_cpuclock_base;
286 	}
287 
288 	systimer_intr_enable();
289 
290 #ifdef DEVICE_POLLING
291 	init_device_poll_pcpu(gd->gd_cpuid);
292 #endif
293 
294 #ifdef IFPOLL_ENABLE
295 	ifpoll_init_pcpu(gd->gd_cpuid);
296 #endif
297 
298 	/*
299 	 * Use a non-queued periodic systimer to prevent multiple ticks from
300 	 * building up if the sysclock jumps forward (8254 gets reset).  The
301 	 * sysclock will never jump backwards.  Our time sync is based on
302 	 * the actual sysclock, not the ticks count.
303 	 */
304 	systimer_init_periodic_nq(&gd->gd_hardclock, hardclock, NULL, hz);
305 	systimer_init_periodic_nq(&gd->gd_statclock, statclock, NULL, stathz);
306 	/* XXX correct the frequency for scheduler / estcpu tests */
307 	systimer_init_periodic_nq(&gd->gd_schedclock, schedclock,
308 				NULL, ESTCPUFREQ);
309 	crit_exit();
310 }
311 
312 /*
313  * This sets the current real time of day.  Timespecs are in seconds and
314  * nanoseconds.  We do not mess with gd_time_seconds and gd_cpuclock_base,
315  * instead we adjust basetime so basetime + gd_* results in the current
316  * time of day.  This way the gd_* fields are guarenteed to represent
317  * a monotonically increasing 'uptime' value.
318  *
319  * When set_timeofday() is called from userland, the system call forces it
320  * onto cpu #0 since only cpu #0 can update basetime_index.
321  */
322 void
323 set_timeofday(struct timespec *ts)
324 {
325 	struct timespec *nbt;
326 	int ni;
327 
328 	/*
329 	 * XXX SMP / non-atomic basetime updates
330 	 */
331 	crit_enter();
332 	ni = (basetime_index + 1) & BASETIME_ARYMASK;
333 	nbt = &basetime[ni];
334 	nanouptime(nbt);
335 	nbt->tv_sec = ts->tv_sec - nbt->tv_sec;
336 	nbt->tv_nsec = ts->tv_nsec - nbt->tv_nsec;
337 	if (nbt->tv_nsec < 0) {
338 	    nbt->tv_nsec += 1000000000;
339 	    --nbt->tv_sec;
340 	}
341 
342 	/*
343 	 * Note that basetime diverges from boottime as the clock drift is
344 	 * compensated for, so we cannot do away with boottime.  When setting
345 	 * the absolute time of day the drift is 0 (for an instant) and we
346 	 * can simply assign boottime to basetime.
347 	 *
348 	 * Note that nanouptime() is based on gd_time_seconds which is drift
349 	 * compensated up to a point (it is guarenteed to remain monotonically
350 	 * increasing).  gd_time_seconds is thus our best uptime guess and
351 	 * suitable for use in the boottime calculation.  It is already taken
352 	 * into account in the basetime calculation above.
353 	 */
354 	boottime.tv_sec = nbt->tv_sec;
355 	ntp_delta = 0;
356 
357 	/*
358 	 * We now have a new basetime, make sure all other cpus have it,
359 	 * then update the index.
360 	 */
361 	cpu_sfence();
362 	basetime_index = ni;
363 
364 	crit_exit();
365 }
366 
367 /*
368  * Each cpu has its own hardclock, but we only increments ticks and softticks
369  * on cpu #0.
370  *
371  * NOTE! systimer! the MP lock might not be held here.  We can only safely
372  * manipulate objects owned by the current cpu.
373  */
374 static void
375 hardclock(systimer_t info, int in_ipi __unused, struct intrframe *frame)
376 {
377 	sysclock_t cputicks;
378 	struct proc *p;
379 	struct globaldata *gd = mycpu;
380 
381 	/*
382 	 * Realtime updates are per-cpu.  Note that timer corrections as
383 	 * returned by microtime() and friends make an additional adjustment
384 	 * using a system-wise 'basetime', but the running time is always
385 	 * taken from the per-cpu globaldata area.  Since the same clock
386 	 * is distributing (XXX SMP) to all cpus, the per-cpu timebases
387 	 * stay in synch.
388 	 *
389 	 * Note that we never allow info->time (aka gd->gd_hardclock.time)
390 	 * to reverse index gd_cpuclock_base, but that it is possible for
391 	 * it to temporarily get behind in the seconds if something in the
392 	 * system locks interrupts for a long period of time.  Since periodic
393 	 * timers count events, though everything should resynch again
394 	 * immediately.
395 	 */
396 	cputicks = info->time - gd->gd_cpuclock_base;
397 	if (cputicks >= sys_cputimer->freq) {
398 		++gd->gd_time_seconds;
399 		gd->gd_cpuclock_base += sys_cputimer->freq;
400 	}
401 
402 	/*
403 	 * The system-wide ticks counter and NTP related timedelta/tickdelta
404 	 * adjustments only occur on cpu #0.  NTP adjustments are accomplished
405 	 * by updating basetime.
406 	 */
407 	if (gd->gd_cpuid == 0) {
408 	    struct timespec *nbt;
409 	    struct timespec nts;
410 	    int leap;
411 	    int ni;
412 
413 	    ++ticks;
414 
415 #if 0
416 	    if (tco->tc_poll_pps)
417 		tco->tc_poll_pps(tco);
418 #endif
419 
420 	    /*
421 	     * Calculate the new basetime index.  We are in a critical section
422 	     * on cpu #0 and can safely play with basetime_index.  Start
423 	     * with the current basetime and then make adjustments.
424 	     */
425 	    ni = (basetime_index + 1) & BASETIME_ARYMASK;
426 	    nbt = &basetime[ni];
427 	    *nbt = basetime[basetime_index];
428 
429 	    /*
430 	     * Apply adjtime corrections.  (adjtime() API)
431 	     *
432 	     * adjtime() only runs on cpu #0 so our critical section is
433 	     * sufficient to access these variables.
434 	     */
435 	    if (ntp_delta != 0) {
436 		nbt->tv_nsec += ntp_tick_delta;
437 		ntp_delta -= ntp_tick_delta;
438 		if ((ntp_delta > 0 && ntp_delta < ntp_tick_delta) ||
439 		    (ntp_delta < 0 && ntp_delta > ntp_tick_delta)) {
440 			ntp_tick_delta = ntp_delta;
441  		}
442  	    }
443 
444 	    /*
445 	     * Apply permanent frequency corrections.  (sysctl API)
446 	     */
447 	    if (ntp_tick_permanent != 0) {
448 		ntp_tick_acc += ntp_tick_permanent;
449 		if (ntp_tick_acc >= (1LL << 32)) {
450 		    nbt->tv_nsec += ntp_tick_acc >> 32;
451 		    ntp_tick_acc -= (ntp_tick_acc >> 32) << 32;
452 		} else if (ntp_tick_acc <= -(1LL << 32)) {
453 		    /* Negate ntp_tick_acc to avoid shifting the sign bit. */
454 		    nbt->tv_nsec -= (-ntp_tick_acc) >> 32;
455 		    ntp_tick_acc += ((-ntp_tick_acc) >> 32) << 32;
456 		}
457  	    }
458 
459 	    if (nbt->tv_nsec >= 1000000000) {
460 		    nbt->tv_sec++;
461 		    nbt->tv_nsec -= 1000000000;
462 	    } else if (nbt->tv_nsec < 0) {
463 		    nbt->tv_sec--;
464 		    nbt->tv_nsec += 1000000000;
465 	    }
466 
467 	    /*
468 	     * Another per-tick compensation.  (for ntp_adjtime() API)
469 	     */
470 	    if (nsec_adj != 0) {
471 		nsec_acc += nsec_adj;
472 		if (nsec_acc >= 0x100000000LL) {
473 		    nbt->tv_nsec += nsec_acc >> 32;
474 		    nsec_acc = (nsec_acc & 0xFFFFFFFFLL);
475 		} else if (nsec_acc <= -0x100000000LL) {
476 		    nbt->tv_nsec -= -nsec_acc >> 32;
477 		    nsec_acc = -(-nsec_acc & 0xFFFFFFFFLL);
478 		}
479 		if (nbt->tv_nsec >= 1000000000) {
480 		    nbt->tv_nsec -= 1000000000;
481 		    ++nbt->tv_sec;
482 		} else if (nbt->tv_nsec < 0) {
483 		    nbt->tv_nsec += 1000000000;
484 		    --nbt->tv_sec;
485 		}
486 	    }
487 
488 	    /************************************************************
489 	     *			LEAP SECOND CORRECTION			*
490 	     ************************************************************
491 	     *
492 	     * Taking into account all the corrections made above, figure
493 	     * out the new real time.  If the seconds field has changed
494 	     * then apply any pending leap-second corrections.
495 	     */
496 	    getnanotime_nbt(nbt, &nts);
497 
498 	    if (time_second != nts.tv_sec) {
499 		/*
500 		 * Apply leap second (sysctl API).  Adjust nts for changes
501 		 * so we do not have to call getnanotime_nbt again.
502 		 */
503 		if (ntp_leap_second) {
504 		    if (ntp_leap_second == nts.tv_sec) {
505 			if (ntp_leap_insert) {
506 			    nbt->tv_sec++;
507 			    nts.tv_sec++;
508 			} else {
509 			    nbt->tv_sec--;
510 			    nts.tv_sec--;
511 			}
512 			ntp_leap_second--;
513 		    }
514 		}
515 
516 		/*
517 		 * Apply leap second (ntp_adjtime() API), calculate a new
518 		 * nsec_adj field.  ntp_update_second() returns nsec_adj
519 		 * as a per-second value but we need it as a per-tick value.
520 		 */
521 		leap = ntp_update_second(time_second, &nsec_adj);
522 		nsec_adj /= hz;
523 		nbt->tv_sec += leap;
524 		nts.tv_sec += leap;
525 
526 		/*
527 		 * Update the time_second 'approximate time' global.
528 		 */
529 		time_second = nts.tv_sec;
530 	    }
531 
532 	    /*
533 	     * Finally, our new basetime is ready to go live!
534 	     */
535 	    cpu_sfence();
536 	    basetime_index = ni;
537 	}
538 
539 	/*
540 	 * lwkt thread scheduler fair queueing
541 	 */
542 	lwkt_schedulerclock(curthread);
543 
544 	/*
545 	 * softticks are handled for all cpus
546 	 */
547 	hardclock_softtick(gd);
548 
549 	/*
550 	 * ITimer handling is per-tick, per-cpu.
551 	 *
552 	 * We must acquire the per-process token in order for ksignal()
553 	 * to be non-blocking.  For the moment this requires an AST fault,
554 	 * the ksignal() cannot be safely issued from this hard interrupt.
555 	 *
556 	 * XXX Even the trytoken here isn't right, and itimer operation in
557 	 *     a multi threaded environment is going to be weird at the
558 	 *     very least.
559 	 */
560 	if ((p = curproc) != NULL && lwkt_trytoken(&p->p_token)) {
561 		crit_enter_hard();
562 		if (frame && CLKF_USERMODE(frame) &&
563 		    timevalisset(&p->p_timer[ITIMER_VIRTUAL].it_value) &&
564 		    itimerdecr(&p->p_timer[ITIMER_VIRTUAL], ustick) == 0) {
565 			p->p_flags |= P_SIGVTALRM;
566 			need_user_resched();
567 		}
568 		if (timevalisset(&p->p_timer[ITIMER_PROF].it_value) &&
569 		    itimerdecr(&p->p_timer[ITIMER_PROF], ustick) == 0) {
570 			p->p_flags |= P_SIGPROF;
571 			need_user_resched();
572 		}
573 		crit_exit_hard();
574 		lwkt_reltoken(&p->p_token);
575 	}
576 	setdelayed();
577 }
578 
579 /*
580  * The statistics clock typically runs at a 125Hz rate, and is intended
581  * to be frequency offset from the hardclock (typ 100Hz).  It is per-cpu.
582  *
583  * NOTE! systimer! the MP lock might not be held here.  We can only safely
584  * manipulate objects owned by the current cpu.
585  *
586  * The stats clock is responsible for grabbing a profiling sample.
587  * Most of the statistics are only used by user-level statistics programs.
588  * The main exceptions are p->p_uticks, p->p_sticks, p->p_iticks, and
589  * p->p_estcpu.
590  *
591  * Like the other clocks, the stat clock is called from what is effectively
592  * a fast interrupt, so the context should be the thread/process that got
593  * interrupted.
594  */
595 static void
596 statclock(systimer_t info, int in_ipi, struct intrframe *frame)
597 {
598 #ifdef GPROF
599 	struct gmonparam *g;
600 	int i;
601 #endif
602 	thread_t td;
603 	struct proc *p;
604 	int bump;
605 	struct timeval tv;
606 	struct timeval *stv;
607 
608 	/*
609 	 * How big was our timeslice relative to the last time?
610 	 */
611 	microuptime(&tv);	/* mpsafe */
612 	stv = &mycpu->gd_stattv;
613 	if (stv->tv_sec == 0) {
614 	    bump = 1;
615 	} else {
616 	    bump = tv.tv_usec - stv->tv_usec +
617 		(tv.tv_sec - stv->tv_sec) * 1000000;
618 	    if (bump < 0)
619 		bump = 0;
620 	    if (bump > 1000000)
621 		bump = 1000000;
622 	}
623 	*stv = tv;
624 
625 	td = curthread;
626 	p = td->td_proc;
627 
628 	if (frame && CLKF_USERMODE(frame)) {
629 		/*
630 		 * Came from userland, handle user time and deal with
631 		 * possible process.
632 		 */
633 		if (p && (p->p_flags & P_PROFIL))
634 			addupc_intr(p, CLKF_PC(frame), 1);
635 		td->td_uticks += bump;
636 
637 		/*
638 		 * Charge the time as appropriate
639 		 */
640 		if (p && p->p_nice > NZERO)
641 			cpu_time.cp_nice += bump;
642 		else
643 			cpu_time.cp_user += bump;
644 	} else {
645 		int intr_nest = mycpu->gd_intr_nesting_level;
646 
647 		if (in_ipi) {
648 			/*
649 			 * IPI processing code will bump gd_intr_nesting_level
650 			 * up by one, which breaks following CLKF_INTR testing,
651 			 * so we substract it by one here.
652 			 */
653 			--intr_nest;
654 		}
655 #ifdef GPROF
656 		/*
657 		 * Kernel statistics are just like addupc_intr, only easier.
658 		 */
659 		g = &_gmonparam;
660 		if (g->state == GMON_PROF_ON && frame) {
661 			i = CLKF_PC(frame) - g->lowpc;
662 			if (i < g->textsize) {
663 				i /= HISTFRACTION * sizeof(*g->kcount);
664 				g->kcount[i]++;
665 			}
666 		}
667 #endif
668 		/*
669 		 * Came from kernel mode, so we were:
670 		 * - handling an interrupt,
671 		 * - doing syscall or trap work on behalf of the current
672 		 *   user process, or
673 		 * - spinning in the idle loop.
674 		 * Whichever it is, charge the time as appropriate.
675 		 * Note that we charge interrupts to the current process,
676 		 * regardless of whether they are ``for'' that process,
677 		 * so that we know how much of its real time was spent
678 		 * in ``non-process'' (i.e., interrupt) work.
679 		 *
680 		 * XXX assume system if frame is NULL.  A NULL frame
681 		 * can occur if ipi processing is done from a crit_exit().
682 		 */
683 		if (frame && CLKF_INTR(intr_nest))
684 			td->td_iticks += bump;
685 		else
686 			td->td_sticks += bump;
687 
688 		if (frame && CLKF_INTR(intr_nest)) {
689 #ifdef DEBUG_PCTRACK
690 			do_pctrack(frame, PCTRACK_INT);
691 #endif
692 			cpu_time.cp_intr += bump;
693 		} else {
694 			if (td == &mycpu->gd_idlethread) {
695 				cpu_time.cp_idle += bump;
696 			} else {
697 #ifdef DEBUG_PCTRACK
698 				if (frame)
699 					do_pctrack(frame, PCTRACK_SYS);
700 #endif
701 				cpu_time.cp_sys += bump;
702 			}
703 		}
704 	}
705 }
706 
707 #ifdef DEBUG_PCTRACK
708 /*
709  * Sample the PC when in the kernel or in an interrupt.  User code can
710  * retrieve the information and generate a histogram or other output.
711  */
712 
713 static void
714 do_pctrack(struct intrframe *frame, int which)
715 {
716 	struct kinfo_pctrack *pctrack;
717 
718 	pctrack = &cputime_pctrack[mycpu->gd_cpuid][which];
719 	pctrack->pc_array[pctrack->pc_index & PCTRACK_ARYMASK] =
720 		(void *)CLKF_PC(frame);
721 	++pctrack->pc_index;
722 }
723 
724 static int
725 sysctl_pctrack(SYSCTL_HANDLER_ARGS)
726 {
727 	struct kinfo_pcheader head;
728 	int error;
729 	int cpu;
730 	int ntrack;
731 
732 	head.pc_ntrack = PCTRACK_SIZE;
733 	head.pc_arysize = PCTRACK_ARYSIZE;
734 
735 	if ((error = SYSCTL_OUT(req, &head, sizeof(head))) != 0)
736 		return (error);
737 
738 	for (cpu = 0; cpu < ncpus; ++cpu) {
739 		for (ntrack = 0; ntrack < PCTRACK_SIZE; ++ntrack) {
740 			error = SYSCTL_OUT(req, &cputime_pctrack[cpu][ntrack],
741 					   sizeof(struct kinfo_pctrack));
742 			if (error)
743 				break;
744 		}
745 		if (error)
746 			break;
747 	}
748 	return (error);
749 }
750 SYSCTL_PROC(_kern, OID_AUTO, pctrack, (CTLTYPE_OPAQUE|CTLFLAG_RD), 0, 0,
751 	sysctl_pctrack, "S,kinfo_pcheader", "CPU PC tracking");
752 
753 #endif
754 
755 /*
756  * The scheduler clock typically runs at a 50Hz rate.  NOTE! systimer,
757  * the MP lock might not be held.  We can safely manipulate parts of curproc
758  * but that's about it.
759  *
760  * Each cpu has its own scheduler clock.
761  */
762 static void
763 schedclock(systimer_t info, int in_ipi __unused, struct intrframe *frame)
764 {
765 	struct lwp *lp;
766 	struct rusage *ru;
767 	struct vmspace *vm;
768 	long rss;
769 
770 	if ((lp = lwkt_preempted_proc()) != NULL) {
771 		/*
772 		 * Account for cpu time used and hit the scheduler.  Note
773 		 * that this call MUST BE MP SAFE, and the BGL IS NOT HELD
774 		 * HERE.
775 		 */
776 		++lp->lwp_cpticks;
777 		lp->lwp_proc->p_usched->schedulerclock(lp, info->periodic,
778 						       info->time);
779 	}
780 	if ((lp = curthread->td_lwp) != NULL) {
781 		/*
782 		 * Update resource usage integrals and maximums.
783 		 */
784 		if ((ru = &lp->lwp_proc->p_ru) &&
785 		    (vm = lp->lwp_proc->p_vmspace) != NULL) {
786 			ru->ru_ixrss += pgtok(vm->vm_tsize);
787 			ru->ru_idrss += pgtok(vm->vm_dsize);
788 			ru->ru_isrss += pgtok(vm->vm_ssize);
789 			if (lwkt_trytoken(&vm->vm_map.token)) {
790 				rss = pgtok(vmspace_resident_count(vm));
791 				if (ru->ru_maxrss < rss)
792 					ru->ru_maxrss = rss;
793 				lwkt_reltoken(&vm->vm_map.token);
794 			}
795 		}
796 	}
797 }
798 
799 /*
800  * Compute number of ticks for the specified amount of time.  The
801  * return value is intended to be used in a clock interrupt timed
802  * operation and guarenteed to meet or exceed the requested time.
803  * If the representation overflows, return INT_MAX.  The minimum return
804  * value is 1 ticks and the function will average the calculation up.
805  * If any value greater then 0 microseconds is supplied, a value
806  * of at least 2 will be returned to ensure that a near-term clock
807  * interrupt does not cause the timeout to occur (degenerately) early.
808  *
809  * Note that limit checks must take into account microseconds, which is
810  * done simply by using the smaller signed long maximum instead of
811  * the unsigned long maximum.
812  *
813  * If ints have 32 bits, then the maximum value for any timeout in
814  * 10ms ticks is 248 days.
815  */
816 int
817 tvtohz_high(struct timeval *tv)
818 {
819 	int ticks;
820 	long sec, usec;
821 
822 	sec = tv->tv_sec;
823 	usec = tv->tv_usec;
824 	if (usec < 0) {
825 		sec--;
826 		usec += 1000000;
827 	}
828 	if (sec < 0) {
829 #ifdef DIAGNOSTIC
830 		if (usec > 0) {
831 			sec++;
832 			usec -= 1000000;
833 		}
834 		kprintf("tvtohz_high: negative time difference "
835 			"%ld sec %ld usec\n",
836 			sec, usec);
837 #endif
838 		ticks = 1;
839 	} else if (sec <= INT_MAX / hz) {
840 		ticks = (int)(sec * hz +
841 			    ((u_long)usec + (ustick - 1)) / ustick) + 1;
842 	} else {
843 		ticks = INT_MAX;
844 	}
845 	return (ticks);
846 }
847 
848 int
849 tstohz_high(struct timespec *ts)
850 {
851 	int ticks;
852 	long sec, nsec;
853 
854 	sec = ts->tv_sec;
855 	nsec = ts->tv_nsec;
856 	if (nsec < 0) {
857 		sec--;
858 		nsec += 1000000000;
859 	}
860 	if (sec < 0) {
861 #ifdef DIAGNOSTIC
862 		if (nsec > 0) {
863 			sec++;
864 			nsec -= 1000000000;
865 		}
866 		kprintf("tstohz_high: negative time difference "
867 			"%ld sec %ld nsec\n",
868 			sec, nsec);
869 #endif
870 		ticks = 1;
871 	} else if (sec <= INT_MAX / hz) {
872 		ticks = (int)(sec * hz +
873 			    ((u_long)nsec + (nstick - 1)) / nstick) + 1;
874 	} else {
875 		ticks = INT_MAX;
876 	}
877 	return (ticks);
878 }
879 
880 
881 /*
882  * Compute number of ticks for the specified amount of time, erroring on
883  * the side of it being too low to ensure that sleeping the returned number
884  * of ticks will not result in a late return.
885  *
886  * The supplied timeval may not be negative and should be normalized.  A
887  * return value of 0 is possible if the timeval converts to less then
888  * 1 tick.
889  *
890  * If ints have 32 bits, then the maximum value for any timeout in
891  * 10ms ticks is 248 days.
892  */
893 int
894 tvtohz_low(struct timeval *tv)
895 {
896 	int ticks;
897 	long sec;
898 
899 	sec = tv->tv_sec;
900 	if (sec <= INT_MAX / hz)
901 		ticks = (int)(sec * hz + (u_long)tv->tv_usec / ustick);
902 	else
903 		ticks = INT_MAX;
904 	return (ticks);
905 }
906 
907 int
908 tstohz_low(struct timespec *ts)
909 {
910 	int ticks;
911 	long sec;
912 
913 	sec = ts->tv_sec;
914 	if (sec <= INT_MAX / hz)
915 		ticks = (int)(sec * hz + (u_long)ts->tv_nsec / nstick);
916 	else
917 		ticks = INT_MAX;
918 	return (ticks);
919 }
920 
921 /*
922  * Start profiling on a process.
923  *
924  * Kernel profiling passes proc0 which never exits and hence
925  * keeps the profile clock running constantly.
926  */
927 void
928 startprofclock(struct proc *p)
929 {
930 	if ((p->p_flags & P_PROFIL) == 0) {
931 		p->p_flags |= P_PROFIL;
932 #if 0	/* XXX */
933 		if (++profprocs == 1 && stathz != 0) {
934 			crit_enter();
935 			psdiv = psratio;
936 			setstatclockrate(profhz);
937 			crit_exit();
938 		}
939 #endif
940 	}
941 }
942 
943 /*
944  * Stop profiling on a process.
945  *
946  * caller must hold p->p_token
947  */
948 void
949 stopprofclock(struct proc *p)
950 {
951 	if (p->p_flags & P_PROFIL) {
952 		p->p_flags &= ~P_PROFIL;
953 #if 0	/* XXX */
954 		if (--profprocs == 0 && stathz != 0) {
955 			crit_enter();
956 			psdiv = 1;
957 			setstatclockrate(stathz);
958 			crit_exit();
959 		}
960 #endif
961 	}
962 }
963 
964 /*
965  * Return information about system clocks.
966  */
967 static int
968 sysctl_kern_clockrate(SYSCTL_HANDLER_ARGS)
969 {
970 	struct kinfo_clockinfo clkinfo;
971 	/*
972 	 * Construct clockinfo structure.
973 	 */
974 	clkinfo.ci_hz = hz;
975 	clkinfo.ci_tick = ustick;
976 	clkinfo.ci_tickadj = ntp_default_tick_delta / 1000;
977 	clkinfo.ci_profhz = profhz;
978 	clkinfo.ci_stathz = stathz ? stathz : hz;
979 	return (sysctl_handle_opaque(oidp, &clkinfo, sizeof clkinfo, req));
980 }
981 
982 SYSCTL_PROC(_kern, KERN_CLOCKRATE, clockrate, CTLTYPE_STRUCT|CTLFLAG_RD,
983 	0, 0, sysctl_kern_clockrate, "S,clockinfo","");
984 
985 /*
986  * We have eight functions for looking at the clock, four for
987  * microseconds and four for nanoseconds.  For each there is fast
988  * but less precise version "get{nano|micro}[up]time" which will
989  * return a time which is up to 1/HZ previous to the call, whereas
990  * the raw version "{nano|micro}[up]time" will return a timestamp
991  * which is as precise as possible.  The "up" variants return the
992  * time relative to system boot, these are well suited for time
993  * interval measurements.
994  *
995  * Each cpu independantly maintains the current time of day, so all
996  * we need to do to protect ourselves from changes is to do a loop
997  * check on the seconds field changing out from under us.
998  *
999  * The system timer maintains a 32 bit count and due to various issues
1000  * it is possible for the calculated delta to occassionally exceed
1001  * sys_cputimer->freq.  If this occurs the sys_cputimer->freq64_nsec
1002  * multiplication can easily overflow, so we deal with the case.  For
1003  * uniformity we deal with the case in the usec case too.
1004  *
1005  * All the [get][micro,nano][time,uptime]() routines are MPSAFE.
1006  */
1007 void
1008 getmicrouptime(struct timeval *tvp)
1009 {
1010 	struct globaldata *gd = mycpu;
1011 	sysclock_t delta;
1012 
1013 	do {
1014 		tvp->tv_sec = gd->gd_time_seconds;
1015 		delta = gd->gd_hardclock.time - gd->gd_cpuclock_base;
1016 	} while (tvp->tv_sec != gd->gd_time_seconds);
1017 
1018 	if (delta >= sys_cputimer->freq) {
1019 		tvp->tv_sec += delta / sys_cputimer->freq;
1020 		delta %= sys_cputimer->freq;
1021 	}
1022 	tvp->tv_usec = (sys_cputimer->freq64_usec * delta) >> 32;
1023 	if (tvp->tv_usec >= 1000000) {
1024 		tvp->tv_usec -= 1000000;
1025 		++tvp->tv_sec;
1026 	}
1027 }
1028 
1029 void
1030 getnanouptime(struct timespec *tsp)
1031 {
1032 	struct globaldata *gd = mycpu;
1033 	sysclock_t delta;
1034 
1035 	do {
1036 		tsp->tv_sec = gd->gd_time_seconds;
1037 		delta = gd->gd_hardclock.time - gd->gd_cpuclock_base;
1038 	} while (tsp->tv_sec != gd->gd_time_seconds);
1039 
1040 	if (delta >= sys_cputimer->freq) {
1041 		tsp->tv_sec += delta / sys_cputimer->freq;
1042 		delta %= sys_cputimer->freq;
1043 	}
1044 	tsp->tv_nsec = (sys_cputimer->freq64_nsec * delta) >> 32;
1045 }
1046 
1047 void
1048 microuptime(struct timeval *tvp)
1049 {
1050 	struct globaldata *gd = mycpu;
1051 	sysclock_t delta;
1052 
1053 	do {
1054 		tvp->tv_sec = gd->gd_time_seconds;
1055 		delta = sys_cputimer->count() - gd->gd_cpuclock_base;
1056 	} while (tvp->tv_sec != gd->gd_time_seconds);
1057 
1058 	if (delta >= sys_cputimer->freq) {
1059 		tvp->tv_sec += delta / sys_cputimer->freq;
1060 		delta %= sys_cputimer->freq;
1061 	}
1062 	tvp->tv_usec = (sys_cputimer->freq64_usec * delta) >> 32;
1063 }
1064 
1065 void
1066 nanouptime(struct timespec *tsp)
1067 {
1068 	struct globaldata *gd = mycpu;
1069 	sysclock_t delta;
1070 
1071 	do {
1072 		tsp->tv_sec = gd->gd_time_seconds;
1073 		delta = sys_cputimer->count() - gd->gd_cpuclock_base;
1074 	} while (tsp->tv_sec != gd->gd_time_seconds);
1075 
1076 	if (delta >= sys_cputimer->freq) {
1077 		tsp->tv_sec += delta / sys_cputimer->freq;
1078 		delta %= sys_cputimer->freq;
1079 	}
1080 	tsp->tv_nsec = (sys_cputimer->freq64_nsec * delta) >> 32;
1081 }
1082 
1083 /*
1084  * realtime routines
1085  */
1086 void
1087 getmicrotime(struct timeval *tvp)
1088 {
1089 	struct globaldata *gd = mycpu;
1090 	struct timespec *bt;
1091 	sysclock_t delta;
1092 
1093 	do {
1094 		tvp->tv_sec = gd->gd_time_seconds;
1095 		delta = gd->gd_hardclock.time - gd->gd_cpuclock_base;
1096 	} while (tvp->tv_sec != gd->gd_time_seconds);
1097 
1098 	if (delta >= sys_cputimer->freq) {
1099 		tvp->tv_sec += delta / sys_cputimer->freq;
1100 		delta %= sys_cputimer->freq;
1101 	}
1102 	tvp->tv_usec = (sys_cputimer->freq64_usec * delta) >> 32;
1103 
1104 	bt = &basetime[basetime_index];
1105 	tvp->tv_sec += bt->tv_sec;
1106 	tvp->tv_usec += bt->tv_nsec / 1000;
1107 	while (tvp->tv_usec >= 1000000) {
1108 		tvp->tv_usec -= 1000000;
1109 		++tvp->tv_sec;
1110 	}
1111 }
1112 
1113 void
1114 getnanotime(struct timespec *tsp)
1115 {
1116 	struct globaldata *gd = mycpu;
1117 	struct timespec *bt;
1118 	sysclock_t delta;
1119 
1120 	do {
1121 		tsp->tv_sec = gd->gd_time_seconds;
1122 		delta = gd->gd_hardclock.time - gd->gd_cpuclock_base;
1123 	} while (tsp->tv_sec != gd->gd_time_seconds);
1124 
1125 	if (delta >= sys_cputimer->freq) {
1126 		tsp->tv_sec += delta / sys_cputimer->freq;
1127 		delta %= sys_cputimer->freq;
1128 	}
1129 	tsp->tv_nsec = (sys_cputimer->freq64_nsec * delta) >> 32;
1130 
1131 	bt = &basetime[basetime_index];
1132 	tsp->tv_sec += bt->tv_sec;
1133 	tsp->tv_nsec += bt->tv_nsec;
1134 	while (tsp->tv_nsec >= 1000000000) {
1135 		tsp->tv_nsec -= 1000000000;
1136 		++tsp->tv_sec;
1137 	}
1138 }
1139 
1140 static void
1141 getnanotime_nbt(struct timespec *nbt, struct timespec *tsp)
1142 {
1143 	struct globaldata *gd = mycpu;
1144 	sysclock_t delta;
1145 
1146 	do {
1147 		tsp->tv_sec = gd->gd_time_seconds;
1148 		delta = gd->gd_hardclock.time - gd->gd_cpuclock_base;
1149 	} while (tsp->tv_sec != gd->gd_time_seconds);
1150 
1151 	if (delta >= sys_cputimer->freq) {
1152 		tsp->tv_sec += delta / sys_cputimer->freq;
1153 		delta %= sys_cputimer->freq;
1154 	}
1155 	tsp->tv_nsec = (sys_cputimer->freq64_nsec * delta) >> 32;
1156 
1157 	tsp->tv_sec += nbt->tv_sec;
1158 	tsp->tv_nsec += nbt->tv_nsec;
1159 	while (tsp->tv_nsec >= 1000000000) {
1160 		tsp->tv_nsec -= 1000000000;
1161 		++tsp->tv_sec;
1162 	}
1163 }
1164 
1165 
1166 void
1167 microtime(struct timeval *tvp)
1168 {
1169 	struct globaldata *gd = mycpu;
1170 	struct timespec *bt;
1171 	sysclock_t delta;
1172 
1173 	do {
1174 		tvp->tv_sec = gd->gd_time_seconds;
1175 		delta = sys_cputimer->count() - gd->gd_cpuclock_base;
1176 	} while (tvp->tv_sec != gd->gd_time_seconds);
1177 
1178 	if (delta >= sys_cputimer->freq) {
1179 		tvp->tv_sec += delta / sys_cputimer->freq;
1180 		delta %= sys_cputimer->freq;
1181 	}
1182 	tvp->tv_usec = (sys_cputimer->freq64_usec * delta) >> 32;
1183 
1184 	bt = &basetime[basetime_index];
1185 	tvp->tv_sec += bt->tv_sec;
1186 	tvp->tv_usec += bt->tv_nsec / 1000;
1187 	while (tvp->tv_usec >= 1000000) {
1188 		tvp->tv_usec -= 1000000;
1189 		++tvp->tv_sec;
1190 	}
1191 }
1192 
1193 void
1194 nanotime(struct timespec *tsp)
1195 {
1196 	struct globaldata *gd = mycpu;
1197 	struct timespec *bt;
1198 	sysclock_t delta;
1199 
1200 	do {
1201 		tsp->tv_sec = gd->gd_time_seconds;
1202 		delta = sys_cputimer->count() - gd->gd_cpuclock_base;
1203 	} while (tsp->tv_sec != gd->gd_time_seconds);
1204 
1205 	if (delta >= sys_cputimer->freq) {
1206 		tsp->tv_sec += delta / sys_cputimer->freq;
1207 		delta %= sys_cputimer->freq;
1208 	}
1209 	tsp->tv_nsec = (sys_cputimer->freq64_nsec * delta) >> 32;
1210 
1211 	bt = &basetime[basetime_index];
1212 	tsp->tv_sec += bt->tv_sec;
1213 	tsp->tv_nsec += bt->tv_nsec;
1214 	while (tsp->tv_nsec >= 1000000000) {
1215 		tsp->tv_nsec -= 1000000000;
1216 		++tsp->tv_sec;
1217 	}
1218 }
1219 
1220 /*
1221  * note: this is not exactly synchronized with real time.  To do that we
1222  * would have to do what microtime does and check for a nanoseconds overflow.
1223  */
1224 time_t
1225 get_approximate_time_t(void)
1226 {
1227 	struct globaldata *gd = mycpu;
1228 	struct timespec *bt;
1229 
1230 	bt = &basetime[basetime_index];
1231 	return(gd->gd_time_seconds + bt->tv_sec);
1232 }
1233 
1234 int
1235 pps_ioctl(u_long cmd, caddr_t data, struct pps_state *pps)
1236 {
1237 	pps_params_t *app;
1238 	struct pps_fetch_args *fapi;
1239 #ifdef PPS_SYNC
1240 	struct pps_kcbind_args *kapi;
1241 #endif
1242 
1243 	switch (cmd) {
1244 	case PPS_IOC_CREATE:
1245 		return (0);
1246 	case PPS_IOC_DESTROY:
1247 		return (0);
1248 	case PPS_IOC_SETPARAMS:
1249 		app = (pps_params_t *)data;
1250 		if (app->mode & ~pps->ppscap)
1251 			return (EINVAL);
1252 		pps->ppsparam = *app;
1253 		return (0);
1254 	case PPS_IOC_GETPARAMS:
1255 		app = (pps_params_t *)data;
1256 		*app = pps->ppsparam;
1257 		app->api_version = PPS_API_VERS_1;
1258 		return (0);
1259 	case PPS_IOC_GETCAP:
1260 		*(int*)data = pps->ppscap;
1261 		return (0);
1262 	case PPS_IOC_FETCH:
1263 		fapi = (struct pps_fetch_args *)data;
1264 		if (fapi->tsformat && fapi->tsformat != PPS_TSFMT_TSPEC)
1265 			return (EINVAL);
1266 		if (fapi->timeout.tv_sec || fapi->timeout.tv_nsec)
1267 			return (EOPNOTSUPP);
1268 		pps->ppsinfo.current_mode = pps->ppsparam.mode;
1269 		fapi->pps_info_buf = pps->ppsinfo;
1270 		return (0);
1271 	case PPS_IOC_KCBIND:
1272 #ifdef PPS_SYNC
1273 		kapi = (struct pps_kcbind_args *)data;
1274 		/* XXX Only root should be able to do this */
1275 		if (kapi->tsformat && kapi->tsformat != PPS_TSFMT_TSPEC)
1276 			return (EINVAL);
1277 		if (kapi->kernel_consumer != PPS_KC_HARDPPS)
1278 			return (EINVAL);
1279 		if (kapi->edge & ~pps->ppscap)
1280 			return (EINVAL);
1281 		pps->kcmode = kapi->edge;
1282 		return (0);
1283 #else
1284 		return (EOPNOTSUPP);
1285 #endif
1286 	default:
1287 		return (ENOTTY);
1288 	}
1289 }
1290 
1291 void
1292 pps_init(struct pps_state *pps)
1293 {
1294 	pps->ppscap |= PPS_TSFMT_TSPEC;
1295 	if (pps->ppscap & PPS_CAPTUREASSERT)
1296 		pps->ppscap |= PPS_OFFSETASSERT;
1297 	if (pps->ppscap & PPS_CAPTURECLEAR)
1298 		pps->ppscap |= PPS_OFFSETCLEAR;
1299 }
1300 
1301 void
1302 pps_event(struct pps_state *pps, sysclock_t count, int event)
1303 {
1304 	struct globaldata *gd;
1305 	struct timespec *tsp;
1306 	struct timespec *osp;
1307 	struct timespec *bt;
1308 	struct timespec ts;
1309 	sysclock_t *pcount;
1310 #ifdef PPS_SYNC
1311 	sysclock_t tcount;
1312 #endif
1313 	sysclock_t delta;
1314 	pps_seq_t *pseq;
1315 	int foff;
1316 	int fhard;
1317 
1318 	gd = mycpu;
1319 
1320 	/* Things would be easier with arrays... */
1321 	if (event == PPS_CAPTUREASSERT) {
1322 		tsp = &pps->ppsinfo.assert_timestamp;
1323 		osp = &pps->ppsparam.assert_offset;
1324 		foff = pps->ppsparam.mode & PPS_OFFSETASSERT;
1325 		fhard = pps->kcmode & PPS_CAPTUREASSERT;
1326 		pcount = &pps->ppscount[0];
1327 		pseq = &pps->ppsinfo.assert_sequence;
1328 	} else {
1329 		tsp = &pps->ppsinfo.clear_timestamp;
1330 		osp = &pps->ppsparam.clear_offset;
1331 		foff = pps->ppsparam.mode & PPS_OFFSETCLEAR;
1332 		fhard = pps->kcmode & PPS_CAPTURECLEAR;
1333 		pcount = &pps->ppscount[1];
1334 		pseq = &pps->ppsinfo.clear_sequence;
1335 	}
1336 
1337 	/* Nothing really happened */
1338 	if (*pcount == count)
1339 		return;
1340 
1341 	*pcount = count;
1342 
1343 	do {
1344 		ts.tv_sec = gd->gd_time_seconds;
1345 		delta = count - gd->gd_cpuclock_base;
1346 	} while (ts.tv_sec != gd->gd_time_seconds);
1347 
1348 	if (delta >= sys_cputimer->freq) {
1349 		ts.tv_sec += delta / sys_cputimer->freq;
1350 		delta %= sys_cputimer->freq;
1351 	}
1352 	ts.tv_nsec = (sys_cputimer->freq64_nsec * delta) >> 32;
1353 	bt = &basetime[basetime_index];
1354 	ts.tv_sec += bt->tv_sec;
1355 	ts.tv_nsec += bt->tv_nsec;
1356 	while (ts.tv_nsec >= 1000000000) {
1357 		ts.tv_nsec -= 1000000000;
1358 		++ts.tv_sec;
1359 	}
1360 
1361 	(*pseq)++;
1362 	*tsp = ts;
1363 
1364 	if (foff) {
1365 		timespecadd(tsp, osp);
1366 		if (tsp->tv_nsec < 0) {
1367 			tsp->tv_nsec += 1000000000;
1368 			tsp->tv_sec -= 1;
1369 		}
1370 	}
1371 #ifdef PPS_SYNC
1372 	if (fhard) {
1373 		/* magic, at its best... */
1374 		tcount = count - pps->ppscount[2];
1375 		pps->ppscount[2] = count;
1376 		if (tcount >= sys_cputimer->freq) {
1377 			delta = (1000000000 * (tcount / sys_cputimer->freq) +
1378 				 sys_cputimer->freq64_nsec *
1379 				 (tcount % sys_cputimer->freq)) >> 32;
1380 		} else {
1381 			delta = (sys_cputimer->freq64_nsec * tcount) >> 32;
1382 		}
1383 		hardpps(tsp, delta);
1384 	}
1385 #endif
1386 }
1387 
1388 /*
1389  * Return the tsc target value for a delay of (ns).
1390  *
1391  * Returns -1 if the TSC is not supported.
1392  */
1393 int64_t
1394 tsc_get_target(int ns)
1395 {
1396 #if defined(_RDTSC_SUPPORTED_)
1397 	if (cpu_feature & CPUID_TSC) {
1398 		return (rdtsc() + tsc_frequency * ns / (int64_t)1000000000);
1399 	}
1400 #endif
1401 	return(-1);
1402 }
1403 
1404 /*
1405  * Compare the tsc against the passed target
1406  *
1407  * Returns +1 if the target has been reached
1408  * Returns  0 if the target has not yet been reached
1409  * Returns -1 if the TSC is not supported.
1410  *
1411  * Typical use:		while (tsc_test_target(target) == 0) { ...poll... }
1412  */
1413 int
1414 tsc_test_target(int64_t target)
1415 {
1416 #if defined(_RDTSC_SUPPORTED_)
1417 	if (cpu_feature & CPUID_TSC) {
1418 		if ((int64_t)(target - rdtsc()) <= 0)
1419 			return(1);
1420 		return(0);
1421 	}
1422 #endif
1423 	return(-1);
1424 }
1425 
1426 /*
1427  * Delay the specified number of nanoseconds using the tsc.  This function
1428  * returns immediately if the TSC is not supported.  At least one cpu_pause()
1429  * will be issued.
1430  */
1431 void
1432 tsc_delay(int ns)
1433 {
1434 	int64_t clk;
1435 
1436 	clk = tsc_get_target(ns);
1437 	cpu_pause();
1438 	while (tsc_test_target(clk) == 0)
1439 		cpu_pause();
1440 }
1441