xref: /dragonfly/sys/kern/kern_clock.c (revision 4e7eb5cc)
1 /*-
2  * Copyright (c) 1997, 1998 Poul-Henning Kamp <phk@FreeBSD.org>
3  * Copyright (c) 1982, 1986, 1991, 1993
4  *	The Regents of the University of California.  All rights reserved.
5  * (c) UNIX System Laboratories, Inc.
6  * All or some portions of this file are derived from material licensed
7  * to the University of California by American Telephone and Telegraph
8  * Co. or Unix System Laboratories, Inc. and are reproduced herein with
9  * the permission of UNIX System Laboratories, Inc.
10  *
11  * Redistribution and use in source and binary forms, with or without
12  * modification, are permitted provided that the following conditions
13  * are met:
14  * 1. Redistributions of source code must retain the above copyright
15  *    notice, this list of conditions and the following disclaimer.
16  * 2. Redistributions in binary form must reproduce the above copyright
17  *    notice, this list of conditions and the following disclaimer in the
18  *    documentation and/or other materials provided with the distribution.
19  * 3. All advertising materials mentioning features or use of this software
20  *    must display the following acknowledgement:
21  *	This product includes software developed by the University of
22  *	California, Berkeley and its contributors.
23  * 4. Neither the name of the University nor the names of its contributors
24  *    may be used to endorse or promote products derived from this software
25  *    without specific prior written permission.
26  *
27  * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
28  * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
29  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
30  * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
31  * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
32  * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
33  * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
34  * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
35  * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
36  * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
37  * SUCH DAMAGE.
38  *
39  *	@(#)kern_clock.c	8.5 (Berkeley) 1/21/94
40  * $FreeBSD: src/sys/kern/kern_clock.c,v 1.105.2.10 2002/10/17 13:19:40 maxim Exp $
41  * $DragonFly: src/sys/kern/kern_clock.c,v 1.14 2004/01/07 20:21:46 dillon Exp $
42  */
43 
44 #include "opt_ntp.h"
45 
46 #include <sys/param.h>
47 #include <sys/systm.h>
48 #include <sys/dkstat.h>
49 #include <sys/callout.h>
50 #include <sys/kernel.h>
51 #include <sys/proc.h>
52 #include <sys/malloc.h>
53 #include <sys/resourcevar.h>
54 #include <sys/signalvar.h>
55 #include <sys/timex.h>
56 #include <sys/timepps.h>
57 #include <vm/vm.h>
58 #include <sys/lock.h>
59 #include <vm/pmap.h>
60 #include <vm/vm_map.h>
61 #include <sys/sysctl.h>
62 #include <sys/thread2.h>
63 
64 #include <machine/cpu.h>
65 #include <machine/limits.h>
66 #include <machine/smp.h>
67 
68 #ifdef GPROF
69 #include <sys/gmon.h>
70 #endif
71 
72 #ifdef DEVICE_POLLING
73 extern void init_device_poll(void);
74 extern void hardclock_device_poll(void);
75 #endif /* DEVICE_POLLING */
76 
77 /*
78  * Number of timecounters used to implement stable storage
79  */
80 #ifndef NTIMECOUNTER
81 #define NTIMECOUNTER	5
82 #endif
83 
84 static MALLOC_DEFINE(M_TIMECOUNTER, "timecounter",
85 	"Timecounter stable storage");
86 
87 static void initclocks (void *dummy);
88 SYSINIT(clocks, SI_SUB_CLOCKS, SI_ORDER_FIRST, initclocks, NULL)
89 
90 static void tco_forward (int force);
91 static void tco_setscales (struct timecounter *tc);
92 static __inline unsigned tco_delta (struct timecounter *tc);
93 
94 /*
95  * Some of these don't belong here, but it's easiest to concentrate them.
96  * Note that cp_time[] counts in microseconds, but most userland programs
97  * just compare relative times against the total by delta.
98  */
99 long cp_time[CPUSTATES];
100 
101 SYSCTL_OPAQUE(_kern, OID_AUTO, cp_time, CTLFLAG_RD, &cp_time, sizeof(cp_time),
102     "LU", "CPU time statistics");
103 
104 long tk_cancc;
105 long tk_nin;
106 long tk_nout;
107 long tk_rawcc;
108 
109 time_t time_second;
110 
111 struct	timeval boottime;
112 SYSCTL_STRUCT(_kern, KERN_BOOTTIME, boottime, CTLFLAG_RD,
113     &boottime, timeval, "System boottime");
114 
115 /*
116  * Which update policy to use.
117  *   0 - every tick, bad hardware may fail with "calcru negative..."
118  *   1 - more resistent to the above hardware, but less efficient.
119  */
120 static int tco_method;
121 
122 /*
123  * Implement a dummy timecounter which we can use until we get a real one
124  * in the air.  This allows the console and other early stuff to use
125  * timeservices.
126  */
127 
128 static unsigned
129 dummy_get_timecount(struct timecounter *tc)
130 {
131 	static unsigned now;
132 	return (++now);
133 }
134 
135 static struct timecounter dummy_timecounter = {
136 	dummy_get_timecount,
137 	0,
138 	~0u,
139 	1000000,
140 	"dummy"
141 };
142 
143 struct timecounter *timecounter = &dummy_timecounter;
144 
145 /*
146  * Clock handling routines.
147  *
148  * This code is written to operate with two timers that run independently of
149  * each other.
150  *
151  * The main timer, running hz times per second, is used to trigger interval
152  * timers, timeouts and rescheduling as needed.
153  *
154  * The second timer handles kernel and user profiling,
155  * and does resource use estimation.  If the second timer is programmable,
156  * it is randomized to avoid aliasing between the two clocks.  For example,
157  * the randomization prevents an adversary from always giving up the cpu
158  * just before its quantum expires.  Otherwise, it would never accumulate
159  * cpu ticks.  The mean frequency of the second timer is stathz.
160  *
161  * If no second timer exists, stathz will be zero; in this case we drive
162  * profiling and statistics off the main clock.  This WILL NOT be accurate;
163  * do not do it unless absolutely necessary.
164  *
165  * The statistics clock may (or may not) be run at a higher rate while
166  * profiling.  This profile clock runs at profhz.  We require that profhz
167  * be an integral multiple of stathz.
168  *
169  * If the statistics clock is running fast, it must be divided by the ratio
170  * profhz/stathz for statistics.  (For profiling, every tick counts.)
171  *
172  * Time-of-day is maintained using a "timecounter", which may or may
173  * not be related to the hardware generating the above mentioned
174  * interrupts.
175  */
176 
177 int	stathz;
178 int	profhz;
179 static int profprocs;
180 int	ticks;
181 static int psticks;			/* profiler ticks */
182 static int psdiv;			/* prof / stat divider */
183 int	psratio;			/* ratio: prof * 100 / stat */
184 
185 /*
186  * Initialize clock frequencies and start both clocks running.
187  */
188 /* ARGSUSED*/
189 static void
190 initclocks(dummy)
191 	void *dummy;
192 {
193 	int i;
194 
195 	/*
196 	 * Set divisors to 1 (normal case) and let the machine-specific
197 	 * code do its bit.
198 	 */
199 	psdiv = 1;
200 	cpu_initclocks();
201 
202 #ifdef DEVICE_POLLING
203 	init_device_poll();
204 #endif
205 
206 	/*
207 	 * Compute profhz/stathz, and fix profhz if needed.
208 	 */
209 	i = stathz ? stathz : hz;
210 	if (profhz == 0)
211 		profhz = i;
212 	psratio = profhz / i;
213 }
214 
215 /*
216  * The real-time timer, interrupting hz times per second.  This is implemented
217  * as a FAST interrupt so it is in the context of the thread it interrupted,
218  * and not in an interrupt thread.  YYY needs help.
219  */
220 void
221 hardclock(frame)
222 	struct clockframe *frame;
223 {
224 	struct proc *p;
225 
226 	p = curproc;
227 	if (p) {
228 		struct pstats *pstats;
229 
230 		/*
231 		 * Run current process's virtual and profile time, as needed.
232 		 */
233 		pstats = p->p_stats;
234 		if (CLKF_USERMODE(frame) &&
235 		    timevalisset(&pstats->p_timer[ITIMER_VIRTUAL].it_value) &&
236 		    itimerdecr(&pstats->p_timer[ITIMER_VIRTUAL], tick) == 0)
237 			psignal(p, SIGVTALRM);
238 		if (timevalisset(&pstats->p_timer[ITIMER_PROF].it_value) &&
239 		    itimerdecr(&pstats->p_timer[ITIMER_PROF], tick) == 0)
240 			psignal(p, SIGPROF);
241 	}
242 
243 #if 0 /* SMP and BETTER_CLOCK */
244 	forward_hardclock(pscnt);
245 #endif
246 
247 	/*
248 	 * If no separate statistics clock is available, run it from here.
249 	 */
250 	if (stathz == 0)
251 		statclock(frame);
252 
253 	tco_forward(0);
254 	ticks++;
255 
256 #ifdef DEVICE_POLLING
257 	hardclock_device_poll();	/* this is very short and quick */
258 #endif /* DEVICE_POLLING */
259 
260 	/*
261 	 * Process callouts at a very low cpu priority, so we don't keep the
262 	 * relatively high clock interrupt priority any longer than necessary.
263 	 */
264 	if (TAILQ_FIRST(&callwheel[ticks & callwheelmask]) != NULL) {
265 		setsoftclock();
266 	} else if (softticks + 1 == ticks) {
267 		++softticks;
268 	}
269 }
270 
271 /*
272  * Compute number of ticks for the specified amount of time.  The
273  * return value is intended to be used in a clock interrupt timed
274  * operation and guarenteed to meet or exceed the requested time.
275  * If the representation overflows, return INT_MAX.  The minimum return
276  * value is 1 ticks and the function will average the calculation up.
277  * If any value greater then 0 microseconds is supplied, a value
278  * of at least 2 will be returned to ensure that a near-term clock
279  * interrupt does not cause the timeout to occur (degenerately) early.
280  *
281  * Note that limit checks must take into account microseconds, which is
282  * done simply by using the smaller signed long maximum instead of
283  * the unsigned long maximum.
284  *
285  * If ints have 32 bits, then the maximum value for any timeout in
286  * 10ms ticks is 248 days.
287  */
288 int
289 tvtohz_high(struct timeval *tv)
290 {
291 	int ticks;
292 	long sec, usec;
293 
294 	sec = tv->tv_sec;
295 	usec = tv->tv_usec;
296 	if (usec < 0) {
297 		sec--;
298 		usec += 1000000;
299 	}
300 	if (sec < 0) {
301 #ifdef DIAGNOSTIC
302 		if (usec > 0) {
303 			sec++;
304 			usec -= 1000000;
305 		}
306 		printf("tvotohz: negative time difference %ld sec %ld usec\n",
307 		       sec, usec);
308 #endif
309 		ticks = 1;
310 	} else if (sec <= INT_MAX / hz) {
311 		ticks = (int)(sec * hz +
312 			    ((u_long)usec + (tick - 1)) / tick) + 1;
313 	} else {
314 		ticks = INT_MAX;
315 	}
316 	return (ticks);
317 }
318 
319 /*
320  * Compute number of ticks for the specified amount of time, erroring on
321  * the side of it being too low to ensure that sleeping the returned number
322  * of ticks will not result in a late return.
323  *
324  * The supplied timeval may not be negative and should be normalized.  A
325  * return value of 0 is possible if the timeval converts to less then
326  * 1 tick.
327  *
328  * If ints have 32 bits, then the maximum value for any timeout in
329  * 10ms ticks is 248 days.
330  */
331 int
332 tvtohz_low(struct timeval *tv)
333 {
334 	int ticks;
335 	long sec;
336 
337 	sec = tv->tv_sec;
338 	if (sec <= INT_MAX / hz)
339 		ticks = (int)(sec * hz + (u_long)tv->tv_usec / tick);
340 	else
341 		ticks = INT_MAX;
342 	return (ticks);
343 }
344 
345 
346 /*
347  * Start profiling on a process.
348  *
349  * Kernel profiling passes proc0 which never exits and hence
350  * keeps the profile clock running constantly.
351  */
352 void
353 startprofclock(p)
354 	struct proc *p;
355 {
356 	int s;
357 
358 	if ((p->p_flag & P_PROFIL) == 0) {
359 		p->p_flag |= P_PROFIL;
360 		if (++profprocs == 1 && stathz != 0) {
361 			s = splstatclock();
362 			psdiv = psratio;
363 			setstatclockrate(profhz);
364 			splx(s);
365 		}
366 	}
367 }
368 
369 /*
370  * Stop profiling on a process.
371  */
372 void
373 stopprofclock(p)
374 	struct proc *p;
375 {
376 	int s;
377 
378 	if (p->p_flag & P_PROFIL) {
379 		p->p_flag &= ~P_PROFIL;
380 		if (--profprocs == 0 && stathz != 0) {
381 			s = splstatclock();
382 			psdiv = 1;
383 			setstatclockrate(stathz);
384 			splx(s);
385 		}
386 	}
387 }
388 
389 /*
390  * Statistics clock.  Grab profile sample, and if divider reaches 0,
391  * do process and kernel statistics.  Most of the statistics are only
392  * used by user-level statistics programs.  The main exceptions are
393  * p->p_uticks, p->p_sticks, p->p_iticks, and p->p_estcpu.
394  *
395  * The statclock should be called from an exclusive, fast interrupt,
396  * so the context should be the thread/process that got interrupted and
397  * not an interrupt thread.
398  */
399 void
400 statclock(frame)
401 	struct clockframe *frame;
402 {
403 #ifdef GPROF
404 	struct gmonparam *g;
405 	int i;
406 #endif
407 	thread_t td;
408 	struct pstats *pstats;
409 	long rss;
410 	struct rusage *ru;
411 	struct vmspace *vm;
412 	struct proc *p;
413 	int bump;
414 	struct timeval tv;
415 	struct timeval *stv;
416 
417 	/*
418 	 * How big was our timeslice relative to the last time
419 	 */
420 	microuptime(&tv);
421 	stv = &mycpu->gd_stattv;
422 	if (stv->tv_sec == 0) {
423 	    bump = 1;
424 	} else {
425 	    bump = tv.tv_usec - stv->tv_usec +
426 		(tv.tv_sec - stv->tv_sec) * 1000000;
427 	    if (bump < 0)
428 		bump = 0;
429 	    if (bump > 1000000)
430 		bump = 1000000;
431 	}
432 	*stv = tv;
433 
434 	td = curthread;
435 	p = td->td_proc;
436 
437 	if (CLKF_USERMODE(frame)) {
438 		/*
439 		 * Came from userland, handle user time and deal with
440 		 * possible process.
441 		 */
442 		if (p && (p->p_flag & P_PROFIL))
443 			addupc_intr(p, CLKF_PC(frame), 1);
444 #if 0	/* SMP and BETTER_CLOCK */
445 		if (stathz != 0)
446 			forward_statclock(pscnt);
447 #endif
448 		td->td_uticks += bump;
449 
450 		/*
451 		 * Charge the time as appropriate
452 		 */
453 		if (p && p->p_nice > NZERO)
454 			cp_time[CP_NICE] += bump;
455 		else
456 			cp_time[CP_USER] += bump;
457 	} else {
458 #ifdef GPROF
459 		/*
460 		 * Kernel statistics are just like addupc_intr, only easier.
461 		 */
462 		g = &_gmonparam;
463 		if (g->state == GMON_PROF_ON) {
464 			i = CLKF_PC(frame) - g->lowpc;
465 			if (i < g->textsize) {
466 				i /= HISTFRACTION * sizeof(*g->kcount);
467 				g->kcount[i]++;
468 			}
469 		}
470 #endif
471 #if 0	/* SMP and BETTER_CLOCK */
472 		if (stathz != 0)
473 			forward_statclock(pscnt);
474 #endif
475 		/*
476 		 * Came from kernel mode, so we were:
477 		 * - handling an interrupt,
478 		 * - doing syscall or trap work on behalf of the current
479 		 *   user process, or
480 		 * - spinning in the idle loop.
481 		 * Whichever it is, charge the time as appropriate.
482 		 * Note that we charge interrupts to the current process,
483 		 * regardless of whether they are ``for'' that process,
484 		 * so that we know how much of its real time was spent
485 		 * in ``non-process'' (i.e., interrupt) work.
486 		 */
487 		if (CLKF_INTR(frame))
488 			td->td_iticks += bump;
489 		else
490 			td->td_sticks += bump;
491 
492 		if (CLKF_INTR(frame)) {
493 			cp_time[CP_INTR] += bump;
494 		} else {
495 			if (td == &mycpu->gd_idlethread)
496 				cp_time[CP_IDLE] += bump;
497 			else
498 				cp_time[CP_SYS] += bump;
499 		}
500 	}
501 
502 	/*
503 	 * bump psticks and check against gd_psticks.  When we hit the
504 	 * 1*hz mark (psdiv ticks) we do the more expensive stuff.  If
505 	 * psdiv changes we reset everything to avoid confusion.
506 	 */
507 	++psticks;
508 	if (psticks < mycpu->gd_psticks && psdiv == mycpu->gd_psdiv)
509 		return;
510 
511 	mycpu->gd_psdiv = psdiv;
512 	mycpu->gd_psticks = psticks + psdiv;
513 
514 	/*
515 	 * XXX YYY DragonFly... need to rewrite all of this,
516 	 * only schedclock is distributed at the moment
517 	 */
518 	schedclock(NULL);
519 #ifdef SMP
520 	if (smp_started && invltlb_ok && !cold && !panicstr) /* YYY */
521 		lwkt_send_ipiq_mask(mycpu->gd_other_cpus, schedclock, NULL);
522 #endif
523 
524 	if (p != NULL) {
525 		/* Update resource usage integrals and maximums. */
526 		if ((pstats = p->p_stats) != NULL &&
527 		    (ru = &pstats->p_ru) != NULL &&
528 		    (vm = p->p_vmspace) != NULL) {
529 			ru->ru_ixrss += pgtok(vm->vm_tsize);
530 			ru->ru_idrss += pgtok(vm->vm_dsize);
531 			ru->ru_isrss += pgtok(vm->vm_ssize);
532 			rss = pgtok(vmspace_resident_count(vm));
533 			if (ru->ru_maxrss < rss)
534 				ru->ru_maxrss = rss;
535 		}
536 	}
537 }
538 
539 /*
540  * Return information about system clocks.
541  */
542 static int
543 sysctl_kern_clockrate(SYSCTL_HANDLER_ARGS)
544 {
545 	struct clockinfo clkinfo;
546 	/*
547 	 * Construct clockinfo structure.
548 	 */
549 	clkinfo.hz = hz;
550 	clkinfo.tick = tick;
551 	clkinfo.tickadj = tickadj;
552 	clkinfo.profhz = profhz;
553 	clkinfo.stathz = stathz ? stathz : hz;
554 	return (sysctl_handle_opaque(oidp, &clkinfo, sizeof clkinfo, req));
555 }
556 
557 SYSCTL_PROC(_kern, KERN_CLOCKRATE, clockrate, CTLTYPE_STRUCT|CTLFLAG_RD,
558 	0, 0, sysctl_kern_clockrate, "S,clockinfo","");
559 
560 static __inline unsigned
561 tco_delta(struct timecounter *tc)
562 {
563 
564 	return ((tc->tc_get_timecount(tc) - tc->tc_offset_count) &
565 	    tc->tc_counter_mask);
566 }
567 
568 /*
569  * We have eight functions for looking at the clock, four for
570  * microseconds and four for nanoseconds.  For each there is fast
571  * but less precise version "get{nano|micro}[up]time" which will
572  * return a time which is up to 1/HZ previous to the call, whereas
573  * the raw version "{nano|micro}[up]time" will return a timestamp
574  * which is as precise as possible.  The "up" variants return the
575  * time relative to system boot, these are well suited for time
576  * interval measurements.
577  */
578 
579 void
580 getmicrotime(struct timeval *tvp)
581 {
582 	struct timecounter *tc;
583 
584 	if (!tco_method) {
585 		tc = timecounter;
586 		*tvp = tc->tc_microtime;
587 	} else {
588 		microtime(tvp);
589 	}
590 }
591 
592 void
593 getnanotime(struct timespec *tsp)
594 {
595 	struct timecounter *tc;
596 
597 	if (!tco_method) {
598 		tc = timecounter;
599 		*tsp = tc->tc_nanotime;
600 	} else {
601 		nanotime(tsp);
602 	}
603 }
604 
605 void
606 microtime(struct timeval *tv)
607 {
608 	struct timecounter *tc;
609 	int delta;
610 
611 	tc = timecounter;
612 	crit_enter();
613 	delta = tco_delta(tc);
614 	tv->tv_sec = tc->tc_offset_sec;
615 	tv->tv_usec = tc->tc_offset_micro;
616 	tv->tv_usec += ((u_int64_t)delta * tc->tc_scale_micro) >> 32;
617 	crit_exit();
618 	tv->tv_usec += boottime.tv_usec;
619 	tv->tv_sec += boottime.tv_sec;
620 	while (tv->tv_usec < 0) {
621 		tv->tv_usec += 1000000;
622 		if (tv->tv_sec > 0)
623 			tv->tv_sec--;
624 	}
625 	while (tv->tv_usec >= 1000000) {
626 		tv->tv_usec -= 1000000;
627 		tv->tv_sec++;
628 	}
629 }
630 
631 void
632 nanotime(struct timespec *ts)
633 {
634 	unsigned count;
635 	u_int64_t delta;
636 	struct timecounter *tc;
637 
638 	tc = timecounter;
639 	crit_enter();
640 	ts->tv_sec = tc->tc_offset_sec;
641 	count = tco_delta(tc);
642 	delta = tc->tc_offset_nano;
643 	crit_exit();
644 	delta += ((u_int64_t)count * tc->tc_scale_nano_f);
645 	delta >>= 32;
646 	delta += ((u_int64_t)count * tc->tc_scale_nano_i);
647 	delta += boottime.tv_usec * 1000;
648 	ts->tv_sec += boottime.tv_sec;
649 	while (delta < 0) {
650 		delta += 1000000000;
651 		if (ts->tv_sec > 0)
652 			ts->tv_sec--;
653 	}
654 	while (delta >= 1000000000) {
655 		delta -= 1000000000;
656 		ts->tv_sec++;
657 	}
658 	ts->tv_nsec = delta;
659 }
660 
661 void
662 getmicrouptime(struct timeval *tvp)
663 {
664 	struct timecounter *tc;
665 
666 	if (!tco_method) {
667 		tc = timecounter;
668 		tvp->tv_sec = tc->tc_offset_sec;
669 		tvp->tv_usec = tc->tc_offset_micro;
670 	} else {
671 		microuptime(tvp);
672 	}
673 }
674 
675 void
676 getnanouptime(struct timespec *tsp)
677 {
678 	struct timecounter *tc;
679 
680 	if (!tco_method) {
681 		tc = timecounter;
682 		tsp->tv_sec = tc->tc_offset_sec;
683 		tsp->tv_nsec = tc->tc_offset_nano >> 32;
684 	} else {
685 		nanouptime(tsp);
686 	}
687 }
688 
689 void
690 microuptime(struct timeval *tv)
691 {
692 	struct timecounter *tc;
693 
694 	tc = timecounter;
695 	tv->tv_sec = tc->tc_offset_sec;
696 	tv->tv_usec = tc->tc_offset_micro;
697 	tv->tv_usec += ((u_int64_t)tco_delta(tc) * tc->tc_scale_micro) >> 32;
698 	while (tv->tv_usec < 0) {
699 		tv->tv_usec += 1000000;
700 		if (tv->tv_sec > 0)
701 			tv->tv_sec--;
702 	}
703 	while (tv->tv_usec >= 1000000) {
704 		tv->tv_usec -= 1000000;
705 		tv->tv_sec++;
706 	}
707 }
708 
709 void
710 nanouptime(struct timespec *ts)
711 {
712 	unsigned count;
713 	u_int64_t delta;
714 	struct timecounter *tc;
715 
716 	tc = timecounter;
717 	ts->tv_sec = tc->tc_offset_sec;
718 	count = tco_delta(tc);
719 	delta = tc->tc_offset_nano;
720 	delta += ((u_int64_t)count * tc->tc_scale_nano_f);
721 	delta >>= 32;
722 	delta += ((u_int64_t)count * tc->tc_scale_nano_i);
723 	while (delta < 0) {
724 		delta += 1000000000;
725 		if (ts->tv_sec > 0)
726 			ts->tv_sec--;
727 	}
728 	while (delta >= 1000000000) {
729 		delta -= 1000000000;
730 		ts->tv_sec++;
731 	}
732 	ts->tv_nsec = delta;
733 }
734 
735 static void
736 tco_setscales(struct timecounter *tc)
737 {
738 	u_int64_t scale;
739 
740 	scale = 1000000000LL << 32;
741 	scale += tc->tc_adjustment;
742 	scale /= tc->tc_tweak->tc_frequency;
743 	tc->tc_scale_micro = scale / 1000;
744 	tc->tc_scale_nano_f = scale & 0xffffffff;
745 	tc->tc_scale_nano_i = scale >> 32;
746 }
747 
748 void
749 update_timecounter(struct timecounter *tc)
750 {
751 	tco_setscales(tc);
752 }
753 
754 void
755 init_timecounter(struct timecounter *tc)
756 {
757 	struct timespec ts1;
758 	struct timecounter *t1, *t2, *t3;
759 	unsigned u;
760 	int i;
761 
762 	u = tc->tc_frequency / tc->tc_counter_mask;
763 	if (u > hz) {
764 		printf("Timecounter \"%s\" frequency %lu Hz"
765 		       " -- Insufficient hz, needs at least %u\n",
766 		       tc->tc_name, (u_long) tc->tc_frequency, u);
767 		return;
768 	}
769 
770 	tc->tc_adjustment = 0;
771 	tc->tc_tweak = tc;
772 	tco_setscales(tc);
773 	tc->tc_offset_count = tc->tc_get_timecount(tc);
774 	if (timecounter == &dummy_timecounter)
775 		tc->tc_avail = tc;
776 	else {
777 		tc->tc_avail = timecounter->tc_tweak->tc_avail;
778 		timecounter->tc_tweak->tc_avail = tc;
779 	}
780 	MALLOC(t1, struct timecounter *, sizeof *t1, M_TIMECOUNTER, M_WAITOK);
781 	tc->tc_other = t1;
782 	*t1 = *tc;
783 	t2 = t1;
784 	for (i = 1; i < NTIMECOUNTER; i++) {
785 		MALLOC(t3, struct timecounter *, sizeof *t3,
786 		    M_TIMECOUNTER, M_WAITOK);
787 		*t3 = *tc;
788 		t3->tc_other = t2;
789 		t2 = t3;
790 	}
791 	t1->tc_other = t3;
792 	tc = t1;
793 
794 	printf("Timecounter \"%s\"  frequency %lu Hz\n",
795 	    tc->tc_name, (u_long)tc->tc_frequency);
796 
797 	/* XXX: For now always start using the counter. */
798 	tc->tc_offset_count = tc->tc_get_timecount(tc);
799 	nanouptime(&ts1);
800 	tc->tc_offset_nano = (u_int64_t)ts1.tv_nsec << 32;
801 	tc->tc_offset_micro = ts1.tv_nsec / 1000;
802 	tc->tc_offset_sec = ts1.tv_sec;
803 	timecounter = tc;
804 }
805 
806 void
807 set_timecounter(struct timespec *ts)
808 {
809 	struct timespec ts2;
810 
811 	nanouptime(&ts2);
812 	boottime.tv_sec = ts->tv_sec - ts2.tv_sec;
813 	boottime.tv_usec = (ts->tv_nsec - ts2.tv_nsec) / 1000;
814 	if (boottime.tv_usec < 0) {
815 		boottime.tv_usec += 1000000;
816 		boottime.tv_sec--;
817 	}
818 	/* fiddle all the little crinkly bits around the fiords... */
819 	tco_forward(1);
820 }
821 
822 static void
823 switch_timecounter(struct timecounter *newtc)
824 {
825 	int s;
826 	struct timecounter *tc;
827 	struct timespec ts;
828 
829 	s = splclock();
830 	tc = timecounter;
831 	if (newtc->tc_tweak == tc->tc_tweak) {
832 		splx(s);
833 		return;
834 	}
835 	newtc = newtc->tc_tweak->tc_other;
836 	nanouptime(&ts);
837 	newtc->tc_offset_sec = ts.tv_sec;
838 	newtc->tc_offset_nano = (u_int64_t)ts.tv_nsec << 32;
839 	newtc->tc_offset_micro = ts.tv_nsec / 1000;
840 	newtc->tc_offset_count = newtc->tc_get_timecount(newtc);
841 	tco_setscales(newtc);
842 	timecounter = newtc;
843 	splx(s);
844 }
845 
846 static struct timecounter *
847 sync_other_counter(void)
848 {
849 	struct timecounter *tc, *tcn, *tco;
850 	unsigned delta;
851 
852 	tco = timecounter;
853 	tc = tco->tc_other;
854 	tcn = tc->tc_other;
855 	*tc = *tco;
856 	tc->tc_other = tcn;
857 	delta = tco_delta(tc);
858 	tc->tc_offset_count += delta;
859 	tc->tc_offset_count &= tc->tc_counter_mask;
860 	tc->tc_offset_nano += (u_int64_t)delta * tc->tc_scale_nano_f;
861 	tc->tc_offset_nano += (u_int64_t)delta * tc->tc_scale_nano_i << 32;
862 	return (tc);
863 }
864 
865 static void
866 tco_forward(int force)
867 {
868 	struct timecounter *tc, *tco;
869 	struct timeval tvt;
870 
871 	tco = timecounter;
872 	tc = sync_other_counter();
873 	/*
874 	 * We may be inducing a tiny error here, the tc_poll_pps() may
875 	 * process a latched count which happens after the tco_delta()
876 	 * in sync_other_counter(), which would extend the previous
877 	 * counters parameters into the domain of this new one.
878 	 * Since the timewindow is very small for this, the error is
879 	 * going to be only a few weenieseconds (as Dave Mills would
880 	 * say), so lets just not talk more about it, OK ?
881 	 */
882 	if (tco->tc_poll_pps)
883 		tco->tc_poll_pps(tco);
884 	if (timedelta != 0) {
885 		tvt = boottime;
886 		tvt.tv_usec += tickdelta;
887 		if (tvt.tv_usec >= 1000000) {
888 			tvt.tv_sec++;
889 			tvt.tv_usec -= 1000000;
890 		} else if (tvt.tv_usec < 0) {
891 			tvt.tv_sec--;
892 			tvt.tv_usec += 1000000;
893 		}
894 		boottime = tvt;
895 		timedelta -= tickdelta;
896 	}
897 
898 	while (tc->tc_offset_nano >= 1000000000ULL << 32) {
899 		tc->tc_offset_nano -= 1000000000ULL << 32;
900 		tc->tc_offset_sec++;
901 		ntp_update_second(tc);	/* XXX only needed if xntpd runs */
902 		tco_setscales(tc);
903 		force++;
904 	}
905 
906 	if (tco_method && !force)
907 		return;
908 
909 	tc->tc_offset_micro = (tc->tc_offset_nano / 1000) >> 32;
910 
911 	/* Figure out the wall-clock time */
912 	tc->tc_nanotime.tv_sec = tc->tc_offset_sec + boottime.tv_sec;
913 	tc->tc_nanotime.tv_nsec =
914 	    (tc->tc_offset_nano >> 32) + boottime.tv_usec * 1000;
915 	tc->tc_microtime.tv_usec = tc->tc_offset_micro + boottime.tv_usec;
916 	while (tc->tc_nanotime.tv_nsec >= 1000000000) {
917 		tc->tc_nanotime.tv_nsec -= 1000000000;
918 		tc->tc_microtime.tv_usec -= 1000000;
919 		tc->tc_nanotime.tv_sec++;
920 	}
921 	time_second = tc->tc_microtime.tv_sec = tc->tc_nanotime.tv_sec;
922 
923 	timecounter = tc;
924 }
925 
926 SYSCTL_NODE(_kern, OID_AUTO, timecounter, CTLFLAG_RW, 0, "");
927 
928 SYSCTL_INT(_kern_timecounter, OID_AUTO, method, CTLFLAG_RW, &tco_method, 0,
929     "This variable determines the method used for updating timecounters. "
930     "If the default algorithm (0) fails with \"calcru negative...\" messages "
931     "try the alternate algorithm (1) which handles bad hardware better."
932 
933 );
934 
935 static int
936 sysctl_kern_timecounter_hardware(SYSCTL_HANDLER_ARGS)
937 {
938 	char newname[32];
939 	struct timecounter *newtc, *tc;
940 	int error;
941 
942 	tc = timecounter->tc_tweak;
943 	strncpy(newname, tc->tc_name, sizeof(newname));
944 	error = sysctl_handle_string(oidp, &newname[0], sizeof(newname), req);
945 	if (error == 0 && req->newptr != NULL &&
946 	    strcmp(newname, tc->tc_name) != 0) {
947 		for (newtc = tc->tc_avail; newtc != tc;
948 		    newtc = newtc->tc_avail) {
949 			if (strcmp(newname, newtc->tc_name) == 0) {
950 				/* Warm up new timecounter. */
951 				(void)newtc->tc_get_timecount(newtc);
952 
953 				switch_timecounter(newtc);
954 				return (0);
955 			}
956 		}
957 		return (EINVAL);
958 	}
959 	return (error);
960 }
961 
962 SYSCTL_PROC(_kern_timecounter, OID_AUTO, hardware, CTLTYPE_STRING | CTLFLAG_RW,
963     0, 0, sysctl_kern_timecounter_hardware, "A", "");
964 
965 
966 int
967 pps_ioctl(u_long cmd, caddr_t data, struct pps_state *pps)
968 {
969 	pps_params_t *app;
970 	struct pps_fetch_args *fapi;
971 #ifdef PPS_SYNC
972 	struct pps_kcbind_args *kapi;
973 #endif
974 
975 	switch (cmd) {
976 	case PPS_IOC_CREATE:
977 		return (0);
978 	case PPS_IOC_DESTROY:
979 		return (0);
980 	case PPS_IOC_SETPARAMS:
981 		app = (pps_params_t *)data;
982 		if (app->mode & ~pps->ppscap)
983 			return (EINVAL);
984 		pps->ppsparam = *app;
985 		return (0);
986 	case PPS_IOC_GETPARAMS:
987 		app = (pps_params_t *)data;
988 		*app = pps->ppsparam;
989 		app->api_version = PPS_API_VERS_1;
990 		return (0);
991 	case PPS_IOC_GETCAP:
992 		*(int*)data = pps->ppscap;
993 		return (0);
994 	case PPS_IOC_FETCH:
995 		fapi = (struct pps_fetch_args *)data;
996 		if (fapi->tsformat && fapi->tsformat != PPS_TSFMT_TSPEC)
997 			return (EINVAL);
998 		if (fapi->timeout.tv_sec || fapi->timeout.tv_nsec)
999 			return (EOPNOTSUPP);
1000 		pps->ppsinfo.current_mode = pps->ppsparam.mode;
1001 		fapi->pps_info_buf = pps->ppsinfo;
1002 		return (0);
1003 	case PPS_IOC_KCBIND:
1004 #ifdef PPS_SYNC
1005 		kapi = (struct pps_kcbind_args *)data;
1006 		/* XXX Only root should be able to do this */
1007 		if (kapi->tsformat && kapi->tsformat != PPS_TSFMT_TSPEC)
1008 			return (EINVAL);
1009 		if (kapi->kernel_consumer != PPS_KC_HARDPPS)
1010 			return (EINVAL);
1011 		if (kapi->edge & ~pps->ppscap)
1012 			return (EINVAL);
1013 		pps->kcmode = kapi->edge;
1014 		return (0);
1015 #else
1016 		return (EOPNOTSUPP);
1017 #endif
1018 	default:
1019 		return (ENOTTY);
1020 	}
1021 }
1022 
1023 void
1024 pps_init(struct pps_state *pps)
1025 {
1026 	pps->ppscap |= PPS_TSFMT_TSPEC;
1027 	if (pps->ppscap & PPS_CAPTUREASSERT)
1028 		pps->ppscap |= PPS_OFFSETASSERT;
1029 	if (pps->ppscap & PPS_CAPTURECLEAR)
1030 		pps->ppscap |= PPS_OFFSETCLEAR;
1031 }
1032 
1033 void
1034 pps_event(struct pps_state *pps, struct timecounter *tc, unsigned count, int event)
1035 {
1036 	struct timespec ts, *tsp, *osp;
1037 	u_int64_t delta;
1038 	unsigned tcount, *pcount;
1039 	int foff, fhard;
1040 	pps_seq_t	*pseq;
1041 
1042 	/* Things would be easier with arrays... */
1043 	if (event == PPS_CAPTUREASSERT) {
1044 		tsp = &pps->ppsinfo.assert_timestamp;
1045 		osp = &pps->ppsparam.assert_offset;
1046 		foff = pps->ppsparam.mode & PPS_OFFSETASSERT;
1047 		fhard = pps->kcmode & PPS_CAPTUREASSERT;
1048 		pcount = &pps->ppscount[0];
1049 		pseq = &pps->ppsinfo.assert_sequence;
1050 	} else {
1051 		tsp = &pps->ppsinfo.clear_timestamp;
1052 		osp = &pps->ppsparam.clear_offset;
1053 		foff = pps->ppsparam.mode & PPS_OFFSETCLEAR;
1054 		fhard = pps->kcmode & PPS_CAPTURECLEAR;
1055 		pcount = &pps->ppscount[1];
1056 		pseq = &pps->ppsinfo.clear_sequence;
1057 	}
1058 
1059 	/* The timecounter changed: bail */
1060 	if (!pps->ppstc ||
1061 	    pps->ppstc->tc_name != tc->tc_name ||
1062 	    tc->tc_name != timecounter->tc_name) {
1063 		pps->ppstc = tc;
1064 		*pcount = count;
1065 		return;
1066 	}
1067 
1068 	/* Nothing really happened */
1069 	if (*pcount == count)
1070 		return;
1071 
1072 	*pcount = count;
1073 
1074 	/* Convert the count to timespec */
1075 	ts.tv_sec = tc->tc_offset_sec;
1076 	tcount = count - tc->tc_offset_count;
1077 	tcount &= tc->tc_counter_mask;
1078 	delta = tc->tc_offset_nano;
1079 	delta += ((u_int64_t)tcount * tc->tc_scale_nano_f);
1080 	delta >>= 32;
1081 	delta += ((u_int64_t)tcount * tc->tc_scale_nano_i);
1082 	delta += boottime.tv_usec * 1000;
1083 	ts.tv_sec += boottime.tv_sec;
1084 	while (delta >= 1000000000) {
1085 		delta -= 1000000000;
1086 		ts.tv_sec++;
1087 	}
1088 	ts.tv_nsec = delta;
1089 
1090 	(*pseq)++;
1091 	*tsp = ts;
1092 
1093 	if (foff) {
1094 		timespecadd(tsp, osp);
1095 		if (tsp->tv_nsec < 0) {
1096 			tsp->tv_nsec += 1000000000;
1097 			tsp->tv_sec -= 1;
1098 		}
1099 	}
1100 #ifdef PPS_SYNC
1101 	if (fhard) {
1102 		/* magic, at its best... */
1103 		tcount = count - pps->ppscount[2];
1104 		pps->ppscount[2] = count;
1105 		tcount &= tc->tc_counter_mask;
1106 		delta = ((u_int64_t)tcount * tc->tc_tweak->tc_scale_nano_f);
1107 		delta >>= 32;
1108 		delta += ((u_int64_t)tcount * tc->tc_tweak->tc_scale_nano_i);
1109 		hardpps(tsp, delta);
1110 	}
1111 #endif
1112 }
1113