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33 * @(#)kern_time.c 8.1 (Berkeley) 6/10/93
34 * $FreeBSD: src/sys/kern/kern_time.c,v 1.68.2.1 2002/10/01 08:00:41 bde Exp $
35 * $DragonFly: src/sys/kern/kern_time.c,v 1.24 2005/04/22 17:41:15 joerg Exp $
38 #include <sys/param.h>
39 #include <sys/systm.h>
41 #include <sys/sysproto.h>
42 #include <sys/resourcevar.h>
43 #include <sys/signalvar.h>
44 #include <sys/kernel.h>
45 #include <sys/systm.h>
46 #include <sys/sysent.h>
47 #include <sys/sysunion.h>
50 #include <sys/vnode.h>
51 #include <sys/sysctl.h>
53 #include <vm/vm_extern.h>
54 #include <sys/msgport2.h>
55 #include <sys/thread2.h>
60 * Time of day and interval timer support.
62 * These routines provide the kernel entry points to get and set
63 * the time-of-day and per-process interval timers. Subroutines
64 * here provide support for adding and subtracting timeval structures
65 * and decrementing interval timers, optionally reloading the interval
66 * timers when they expire.
69 static int nanosleep1 (struct timespec *rqt,
70 struct timespec *rmt);
71 static int settime (struct timeval *);
72 static void timevalfix (struct timeval *);
73 static void no_lease_updatetime (int);
75 static int sleep_hard_us = 100;
76 SYSCTL_INT(_kern, OID_AUTO, sleep_hard_us, CTLFLAG_RW, &sleep_hard_us, 0, "")
79 no_lease_updatetime(deltat)
84 void (*lease_updatetime) (int) = no_lease_updatetime;
90 struct timeval delta, tv1, tv2;
91 static struct timeval maxtime, laststep;
95 if ((origcpu = mycpu->gd_cpuid) != 0)
96 lwkt_setcpu_self(globaldata_find(0));
101 timevalsub(&delta, &tv1);
104 * If the system is secure, we do not allow the time to be
105 * set to a value earlier than 1 second less than the highest
106 * time we have yet seen. The worst a miscreant can do in
107 * this circumstance is "freeze" time. He couldn't go
110 * We similarly do not allow the clock to be stepped more
111 * than one second, nor more than once per second. This allows
112 * a miscreant to make the clock march double-time, but no worse.
114 if (securelevel > 1) {
115 if (delta.tv_sec < 0 || delta.tv_usec < 0) {
117 * Update maxtime to latest time we've seen.
119 if (tv1.tv_sec > maxtime.tv_sec)
122 timevalsub(&tv2, &maxtime);
123 if (tv2.tv_sec < -1) {
124 tv->tv_sec = maxtime.tv_sec - 1;
125 printf("Time adjustment clamped to -1 second\n");
128 if (tv1.tv_sec == laststep.tv_sec) {
132 if (delta.tv_sec > 1) {
133 tv->tv_sec = tv1.tv_sec + 1;
134 printf("Time adjustment clamped to +1 second\n");
140 ts.tv_sec = tv->tv_sec;
141 ts.tv_nsec = tv->tv_usec * 1000;
143 lease_updatetime(delta.tv_sec);
147 lwkt_setcpu_self(globaldata_find(origcpu));
155 clock_gettime(struct clock_gettime_args *uap)
159 switch(uap->clock_id) {
162 return (copyout(&ats, uap->tp, sizeof(ats)));
163 case CLOCK_MONOTONIC:
165 return (copyout(&ats, uap->tp, sizeof(ats)));
173 clock_settime(struct clock_settime_args *uap)
175 struct thread *td = curthread;
180 if ((error = suser(td)) != 0)
182 switch(uap->clock_id) {
184 if ((error = copyin(uap->tp, &ats, sizeof(ats))) != 0)
186 if (ats.tv_nsec < 0 || ats.tv_nsec >= 1000000000)
188 /* XXX Don't convert nsec->usec and back */
189 TIMESPEC_TO_TIMEVAL(&atv, &ats);
190 error = settime(&atv);
198 clock_getres(struct clock_getres_args *uap)
202 switch(uap->clock_id) {
204 case CLOCK_MONOTONIC:
206 * Round up the result of the division cheaply
207 * by adding 1. Rounding up is especially important
208 * if rounding down would give 0. Perfect rounding
212 ts.tv_nsec = 1000000000 / cputimer_freq + 1;
213 return(copyout(&ts, uap->tp, sizeof(ts)));
222 * This is a general helper function for nanosleep() (aka sleep() aka
225 * If there is less then one tick's worth of time left and
226 * we haven't done a yield, or the remaining microseconds is
227 * ridiculously low, do a yield. This avoids having
228 * to deal with systimer overheads when the system is under
229 * heavy loads. If we have done a yield already then use
230 * a systimer and an uninterruptable thread wait.
232 * If there is more then a tick's worth of time left,
233 * calculate the baseline ticks and use an interruptable
234 * tsleep, then handle the fine-grained delay on the next
235 * loop. This usually results in two sleeps occuring, a long one
239 ns1_systimer(systimer_t info)
241 lwkt_schedule(info->data);
245 nanosleep1(struct timespec *rqt, struct timespec *rmt)
248 struct timespec ts, ts2, ts3;
253 if (rqt->tv_nsec < 0 || rqt->tv_nsec >= 1000000000)
255 if (rqt->tv_sec < 0 || (rqt->tv_sec == 0 && rqt->tv_nsec == 0))
258 timespecadd(&ts, rqt); /* ts = target timestamp compare */
259 TIMESPEC_TO_TIMEVAL(&tv, rqt); /* tv = sleep interval */
264 struct systimer info;
266 ticks = tv.tv_usec / tick; /* approximate */
268 if (tv.tv_sec == 0 && ticks == 0) {
269 thread_t td = curthread;
270 if (tried_yield || tv.tv_usec < sleep_hard_us) {
274 crit_enter_quick(td);
275 systimer_init_oneshot(&info, ns1_systimer,
277 lwkt_deschedule_self(td);
280 systimer_del(&info); /* make sure it's gone */
282 error = iscaught(td->td_proc);
283 } else if (tv.tv_sec == 0) {
284 error = tsleep(&nanowait, PCATCH, "nanslp", ticks);
286 ticks = tvtohz_low(&tv); /* also handles overflow */
287 error = tsleep(&nanowait, PCATCH, "nanslp", ticks);
290 if (error && error != EWOULDBLOCK) {
291 if (error == ERESTART)
294 timespecsub(&ts, &ts2);
301 if (timespeccmp(&ts2, &ts, >=))
304 timespecsub(&ts3, &ts2);
305 TIMESPEC_TO_TIMEVAL(&tv, &ts3);
309 static void nanosleep_done(void *arg);
310 static void nanosleep_copyout(union sysunion *sysun);
314 nanosleep(struct nanosleep_args *uap)
317 struct sysmsg_sleep *smsleep = &uap->sysmsg.sm.sleep;
319 error = copyin(uap->rqtp, &smsleep->rqt, sizeof(smsleep->rqt));
323 * YYY clean this up to always use the callout, note that an abort
324 * implementation should record the residual in the async case.
326 if (uap->sysmsg.lmsg.ms_flags & MSGF_ASYNC) {
329 ticks = (quad_t)smsleep->rqt.tv_nsec * hz / 1000000000LL;
330 if (smsleep->rqt.tv_sec)
331 ticks += (quad_t)smsleep->rqt.tv_sec * hz;
338 uap->sysmsg.copyout = nanosleep_copyout;
339 uap->sysmsg.lmsg.ms_flags &= ~MSGF_DONE;
340 callout_init(&smsleep->timer);
341 callout_reset(&smsleep->timer, ticks, nanosleep_done, uap);
346 * Old synchronous sleep code, copyout the residual if
347 * nanosleep was interrupted.
349 error = nanosleep1(&smsleep->rqt, &smsleep->rmt);
350 if (error && uap->rmtp)
351 error = copyout(&smsleep->rmt, uap->rmtp, sizeof(smsleep->rmt));
357 * Asynch completion for the nanosleep() syscall. This function may be
358 * called from any context and cannot legally access the originating
359 * thread, proc, or its user space.
361 * YYY change the callout interface API so we can simply assign the replymsg
362 * function to it directly.
365 nanosleep_done(void *arg)
367 struct nanosleep_args *uap = arg;
368 lwkt_msg_t msg = &uap->sysmsg.lmsg;
370 lwkt_replymsg(msg, 0);
374 * Asynch return for the nanosleep() syscall, called in the context of the
375 * originating thread when it pulls the message off the reply port. This
376 * function is responsible for any copyouts to userland. Kernel threads
377 * which do their own internal system calls will not usually call the return
381 nanosleep_copyout(union sysunion *sysun)
383 struct nanosleep_args *uap = &sysun->nanosleep;
384 struct sysmsg_sleep *smsleep = &uap->sysmsg.sm.sleep;
386 if (sysun->lmsg.ms_error && uap->rmtp) {
387 sysun->lmsg.ms_error =
388 copyout(&smsleep->rmt, uap->rmtp, sizeof(smsleep->rmt));
394 gettimeofday(struct gettimeofday_args *uap)
401 if ((error = copyout((caddr_t)&atv, (caddr_t)uap->tp,
406 error = copyout((caddr_t)&tz, (caddr_t)uap->tzp,
413 settimeofday(struct settimeofday_args *uap)
415 struct thread *td = curthread;
420 if ((error = suser(td)))
422 /* Verify all parameters before changing time. */
424 if ((error = copyin((caddr_t)uap->tv, (caddr_t)&atv,
427 if (atv.tv_usec < 0 || atv.tv_usec >= 1000000)
431 (error = copyin((caddr_t)uap->tzp, (caddr_t)&atz, sizeof(atz))))
433 if (uap->tv && (error = settime(&atv)))
441 kern_adjtime_common(void)
443 if ((ntp_delta >= 0 && ntp_delta < ntp_default_tick_delta) ||
444 (ntp_delta < 0 && ntp_delta > ntp_default_tick_delta))
445 ntp_tick_delta = ntp_delta;
446 else if (ntp_delta > ntp_big_delta)
447 ntp_tick_delta = 10 * ntp_default_tick_delta;
448 else if (ntp_delta < -ntp_big_delta)
449 ntp_tick_delta = -10 * ntp_default_tick_delta;
450 else if (ntp_delta > 0)
451 ntp_tick_delta = ntp_default_tick_delta;
453 ntp_tick_delta = -ntp_default_tick_delta;
457 kern_adjtime(int64_t delta, int64_t *odelta)
461 if ((origcpu = mycpu->gd_cpuid) != 0)
462 lwkt_setcpu_self(globaldata_find(0));
467 kern_adjtime_common();
471 lwkt_setcpu_self(globaldata_find(origcpu));
475 kern_reladjtime(int64_t delta)
479 if ((origcpu = mycpu->gd_cpuid) != 0)
480 lwkt_setcpu_self(globaldata_find(0));
484 kern_adjtime_common();
488 lwkt_setcpu_self(globaldata_find(origcpu));
492 kern_adjfreq(int64_t rate)
496 if ((origcpu = mycpu->gd_cpuid) != 0)
497 lwkt_setcpu_self(globaldata_find(0));
500 ntp_tick_permanent = rate;
504 lwkt_setcpu_self(globaldata_find(origcpu));
509 adjtime(struct adjtime_args *uap)
511 struct thread *td = curthread;
513 int64_t ndelta, odelta;
516 if ((error = suser(td)))
519 copyin((caddr_t)uap->delta, (caddr_t)&atv, sizeof(struct timeval))))
523 * Compute the total correction and the rate at which to apply it.
524 * Round the adjustment down to a whole multiple of the per-tick
525 * delta, so that after some number of incremental changes in
526 * hardclock(), tickdelta will become zero, lest the correction
527 * overshoot and start taking us away from the desired final time.
529 ndelta = atv.tv_sec * 1000000000 + atv.tv_usec * 1000;
530 kern_adjtime(ndelta, &odelta);
533 atv.tv_sec = odelta / 1000000000;
534 atv.tv_usec = odelta % 1000000 / 1000;
535 (void) copyout((caddr_t)&atv, (caddr_t)uap->olddelta,
536 sizeof(struct timeval));
542 sysctl_adjtime(SYSCTL_HANDLER_ARGS)
547 if (req->oldptr != NULL) {
549 error = SYSCTL_OUT(req, &delta, sizeof(delta));
553 if (req->newptr != NULL) {
554 if (suser(curthread))
556 error = SYSCTL_IN(req, &delta, sizeof(delta));
559 kern_reladjtime(delta);
565 sysctl_adjfreq(SYSCTL_HANDLER_ARGS)
570 if (req->oldptr != NULL) {
571 freqdelta = ntp_tick_permanent * hz;
572 error = SYSCTL_OUT(req, &freqdelta, sizeof(freqdelta));
576 if (req->newptr != NULL) {
577 if (suser(curthread))
579 error = SYSCTL_IN(req, &freqdelta, sizeof(freqdelta));
584 kern_adjfreq(freqdelta);
589 SYSCTL_NODE(_kern, OID_AUTO, ntp, CTLFLAG_RW, 0, "NTP related controls");
590 SYSCTL_PROC(_kern_ntp, OID_AUTO, permanent,
591 CTLTYPE_OPAQUE|CTLFLAG_RW, 0, 0,
592 sysctl_adjfreq, "LU", "permanent correction per second");
593 SYSCTL_OPAQUE(_kern_ntp, OID_AUTO, delta, CTLFLAG_RD,
594 &ntp_delta, sizeof(ntp_delta), "LU",
596 SYSCTL_OPAQUE(_kern_ntp, OID_AUTO, big_delta, CTLFLAG_RD,
597 &ntp_big_delta, sizeof(ntp_big_delta), "LU",
598 "threshold for fast adjustment");
599 SYSCTL_OPAQUE(_kern_ntp, OID_AUTO, tick_delta, CTLFLAG_RD,
600 &ntp_tick_delta, sizeof(ntp_tick_delta), "LU",
601 "per-tick adjustment");
602 SYSCTL_OPAQUE(_kern_ntp, OID_AUTO, default_tick_delta, CTLFLAG_RD,
603 &ntp_default_tick_delta, sizeof(ntp_default_tick_delta), "LU",
604 "default per-tick adjustment");
605 SYSCTL_OPAQUE(_kern_ntp, OID_AUTO, next_leap_second, CTLFLAG_RW,
606 &ntp_leap_second, sizeof(ntp_leap_second), "LU",
608 SYSCTL_INT(_kern_ntp, OID_AUTO, insert_leap_second, CTLFLAG_RW,
609 &ntp_leap_insert, 0, "insert or remove leap second");
610 SYSCTL_PROC(_kern_ntp, OID_AUTO, adjust,
611 CTLTYPE_OPAQUE|CTLFLAG_RW, 0, 0,
612 sysctl_adjtime, "", "relative adjust for delta");
615 * Get value of an interval timer. The process virtual and
616 * profiling virtual time timers are kept in the p_stats area, since
617 * they can be swapped out. These are kept internally in the
618 * way they are specified externally: in time until they expire.
620 * The real time interval timer is kept in the process table slot
621 * for the process, and its value (it_value) is kept as an
622 * absolute time rather than as a delta, so that it is easy to keep
623 * periodic real-time signals from drifting.
625 * Virtual time timers are processed in the hardclock() routine of
626 * kern_clock.c. The real time timer is processed by a timeout
627 * routine, called from the softclock() routine. Since a callout
628 * may be delayed in real time due to interrupt processing in the system,
629 * it is possible for the real time timeout routine (realitexpire, given below),
630 * to be delayed in real time past when it is supposed to occur. It
631 * does not suffice, therefore, to reload the real timer .it_value from the
632 * real time timers .it_interval. Rather, we compute the next time in
633 * absolute time the timer should go off.
637 getitimer(struct getitimer_args *uap)
639 struct proc *p = curproc;
641 struct itimerval aitv;
643 if (uap->which > ITIMER_PROF)
646 if (uap->which == ITIMER_REAL) {
648 * Convert from absolute to relative time in .it_value
649 * part of real time timer. If time for real time timer
650 * has passed return 0, else return difference between
651 * current time and time for the timer to go off.
653 aitv = p->p_realtimer;
654 if (timevalisset(&aitv.it_value)) {
655 getmicrouptime(&ctv);
656 if (timevalcmp(&aitv.it_value, &ctv, <))
657 timevalclear(&aitv.it_value);
659 timevalsub(&aitv.it_value, &ctv);
662 aitv = p->p_stats->p_timer[uap->which];
665 return (copyout((caddr_t)&aitv, (caddr_t)uap->itv,
666 sizeof (struct itimerval)));
671 setitimer(struct setitimer_args *uap)
673 struct itimerval aitv;
675 struct itimerval *itvp;
676 struct proc *p = curproc;
679 if (uap->which > ITIMER_PROF)
682 if (itvp && (error = copyin((caddr_t)itvp, (caddr_t)&aitv,
683 sizeof(struct itimerval))))
685 if ((uap->itv = uap->oitv) &&
686 (error = getitimer((struct getitimer_args *)uap)))
690 if (itimerfix(&aitv.it_value))
692 if (!timevalisset(&aitv.it_value))
693 timevalclear(&aitv.it_interval);
694 else if (itimerfix(&aitv.it_interval))
697 if (uap->which == ITIMER_REAL) {
698 if (timevalisset(&p->p_realtimer.it_value))
699 callout_stop(&p->p_ithandle);
700 if (timevalisset(&aitv.it_value))
701 callout_reset(&p->p_ithandle,
702 tvtohz_high(&aitv.it_value), realitexpire, p);
703 getmicrouptime(&ctv);
704 timevaladd(&aitv.it_value, &ctv);
705 p->p_realtimer = aitv;
707 p->p_stats->p_timer[uap->which] = aitv;
714 * Real interval timer expired:
715 * send process whose timer expired an alarm signal.
716 * If time is not set up to reload, then just return.
717 * Else compute next time timer should go off which is > current time.
718 * This is where delay in processing this timeout causes multiple
719 * SIGALRM calls to be compressed into one.
720 * tvtohz_high() always adds 1 to allow for the time until the next clock
721 * interrupt being strictly less than 1 clock tick, but we don't want
722 * that here since we want to appear to be in sync with the clock
723 * interrupt even when we're delayed.
730 struct timeval ctv, ntv;
732 p = (struct proc *)arg;
734 if (!timevalisset(&p->p_realtimer.it_interval)) {
735 timevalclear(&p->p_realtimer.it_value);
740 timevaladd(&p->p_realtimer.it_value,
741 &p->p_realtimer.it_interval);
742 getmicrouptime(&ctv);
743 if (timevalcmp(&p->p_realtimer.it_value, &ctv, >)) {
744 ntv = p->p_realtimer.it_value;
745 timevalsub(&ntv, &ctv);
746 callout_reset(&p->p_ithandle, tvtohz_low(&ntv),
756 * Check that a proposed value to load into the .it_value or
757 * .it_interval part of an interval timer is acceptable, and
758 * fix it to have at least minimal value (i.e. if it is less
759 * than the resolution of the clock, round it up.)
766 if (tv->tv_sec < 0 || tv->tv_sec > 100000000 ||
767 tv->tv_usec < 0 || tv->tv_usec >= 1000000)
769 if (tv->tv_sec == 0 && tv->tv_usec != 0 && tv->tv_usec < tick)
775 * Decrement an interval timer by a specified number
776 * of microseconds, which must be less than a second,
777 * i.e. < 1000000. If the timer expires, then reload
778 * it. In this case, carry over (usec - old value) to
779 * reduce the value reloaded into the timer so that
780 * the timer does not drift. This routine assumes
781 * that it is called in a context where the timers
782 * on which it is operating cannot change in value.
785 itimerdecr(itp, usec)
786 struct itimerval *itp;
790 if (itp->it_value.tv_usec < usec) {
791 if (itp->it_value.tv_sec == 0) {
792 /* expired, and already in next interval */
793 usec -= itp->it_value.tv_usec;
796 itp->it_value.tv_usec += 1000000;
797 itp->it_value.tv_sec--;
799 itp->it_value.tv_usec -= usec;
801 if (timevalisset(&itp->it_value))
803 /* expired, exactly at end of interval */
805 if (timevalisset(&itp->it_interval)) {
806 itp->it_value = itp->it_interval;
807 itp->it_value.tv_usec -= usec;
808 if (itp->it_value.tv_usec < 0) {
809 itp->it_value.tv_usec += 1000000;
810 itp->it_value.tv_sec--;
813 itp->it_value.tv_usec = 0; /* sec is already 0 */
818 * Add and subtract routines for timevals.
819 * N.B.: subtract routine doesn't deal with
820 * results which are before the beginning,
821 * it just gets very confused in this case.
826 struct timeval *t1, *t2;
829 t1->tv_sec += t2->tv_sec;
830 t1->tv_usec += t2->tv_usec;
836 struct timeval *t1, *t2;
839 t1->tv_sec -= t2->tv_sec;
840 t1->tv_usec -= t2->tv_usec;
849 if (t1->tv_usec < 0) {
851 t1->tv_usec += 1000000;
853 if (t1->tv_usec >= 1000000) {
855 t1->tv_usec -= 1000000;
860 * ratecheck(): simple time-based rate-limit checking.
863 ratecheck(struct timeval *lasttime, const struct timeval *mininterval)
865 struct timeval tv, delta;
868 getmicrouptime(&tv); /* NB: 10ms precision */
870 timevalsub(&delta, lasttime);
873 * check for 0,0 is so that the message will be seen at least once,
874 * even if interval is huge.
876 if (timevalcmp(&delta, mininterval, >=) ||
877 (lasttime->tv_sec == 0 && lasttime->tv_usec == 0)) {
886 * ppsratecheck(): packets (or events) per second limitation.
888 * Return 0 if the limit is to be enforced (e.g. the caller
889 * should drop a packet because of the rate limitation).
891 * maxpps of 0 always causes zero to be returned. maxpps of -1
892 * always causes 1 to be returned; this effectively defeats rate
895 * Note that we maintain the struct timeval for compatibility
896 * with other bsd systems. We reuse the storage and just monitor
897 * clock ticks for minimal overhead.
900 ppsratecheck(struct timeval *lasttime, int *curpps, int maxpps)
905 * Reset the last time and counter if this is the first call
906 * or more than a second has passed since the last update of
910 if (lasttime->tv_sec == 0 || (u_int)(now - lasttime->tv_sec) >= hz) {
911 lasttime->tv_sec = now;
913 return (maxpps != 0);
915 (*curpps)++; /* NB: ignore potential overflow */
916 return (maxpps < 0 || *curpps < maxpps);