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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 1.29 2005/06/01 17:43:42 dillon 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 / sys_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_get_ntp_delta(int64_t *delta)
479 if ((origcpu = mycpu->gd_cpuid) != 0)
480 lwkt_setcpu_self(globaldata_find(0));
487 lwkt_setcpu_self(globaldata_find(origcpu));
491 kern_reladjtime(int64_t delta)
495 if ((origcpu = mycpu->gd_cpuid) != 0)
496 lwkt_setcpu_self(globaldata_find(0));
500 kern_adjtime_common();
504 lwkt_setcpu_self(globaldata_find(origcpu));
508 kern_adjfreq(int64_t rate)
512 if ((origcpu = mycpu->gd_cpuid) != 0)
513 lwkt_setcpu_self(globaldata_find(0));
516 ntp_tick_permanent = rate;
520 lwkt_setcpu_self(globaldata_find(origcpu));
525 adjtime(struct adjtime_args *uap)
527 struct thread *td = curthread;
529 int64_t ndelta, odelta;
532 if ((error = suser(td)))
535 copyin((caddr_t)uap->delta, (caddr_t)&atv, sizeof(struct timeval))))
539 * Compute the total correction and the rate at which to apply it.
540 * Round the adjustment down to a whole multiple of the per-tick
541 * delta, so that after some number of incremental changes in
542 * hardclock(), tickdelta will become zero, lest the correction
543 * overshoot and start taking us away from the desired final time.
545 ndelta = (int64_t)atv.tv_sec * 1000000000 + atv.tv_usec * 1000;
546 kern_adjtime(ndelta, &odelta);
549 atv.tv_sec = odelta / 1000000000;
550 atv.tv_usec = odelta % 1000000 / 1000;
551 (void) copyout((caddr_t)&atv, (caddr_t)uap->olddelta,
552 sizeof(struct timeval));
558 sysctl_adjtime(SYSCTL_HANDLER_ARGS)
563 if (req->newptr != NULL) {
564 if (suser(curthread))
566 error = SYSCTL_IN(req, &delta, sizeof(delta));
569 kern_reladjtime(delta);
573 kern_get_ntp_delta(&delta);
574 error = SYSCTL_OUT(req, &delta, sizeof(delta));
579 * delta is in nanoseconds.
582 sysctl_delta(SYSCTL_HANDLER_ARGS)
584 int64_t delta, old_delta;
587 if (req->newptr != NULL) {
588 if (suser(curthread))
590 error = SYSCTL_IN(req, &delta, sizeof(delta));
593 kern_adjtime(delta, &old_delta);
596 if (req->oldptr != NULL)
597 kern_get_ntp_delta(&old_delta);
598 error = SYSCTL_OUT(req, &old_delta, sizeof(old_delta));
603 * frequency is in nanoseconds per second shifted left 32.
604 * kern_adjfreq() needs it in nanoseconds per tick shifted left 32.
607 sysctl_adjfreq(SYSCTL_HANDLER_ARGS)
612 if (req->newptr != NULL) {
613 if (suser(curthread))
615 error = SYSCTL_IN(req, &freqdelta, sizeof(freqdelta));
620 kern_adjfreq(freqdelta);
623 if (req->oldptr != NULL)
624 freqdelta = ntp_tick_permanent * hz;
625 error = SYSCTL_OUT(req, &freqdelta, sizeof(freqdelta));
632 SYSCTL_NODE(_kern, OID_AUTO, ntp, CTLFLAG_RW, 0, "NTP related controls");
633 SYSCTL_PROC(_kern_ntp, OID_AUTO, permanent,
634 CTLTYPE_QUAD|CTLFLAG_RW, 0, 0,
635 sysctl_adjfreq, "Q", "permanent correction per second");
636 SYSCTL_PROC(_kern_ntp, OID_AUTO, delta,
637 CTLTYPE_QUAD|CTLFLAG_RW, 0, 0,
638 sysctl_delta, "Q", "one-time delta");
639 SYSCTL_OPAQUE(_kern_ntp, OID_AUTO, big_delta, CTLFLAG_RD,
640 &ntp_big_delta, sizeof(ntp_big_delta), "Q",
641 "threshold for fast adjustment");
642 SYSCTL_OPAQUE(_kern_ntp, OID_AUTO, tick_delta, CTLFLAG_RD,
643 &ntp_tick_delta, sizeof(ntp_tick_delta), "LU",
644 "per-tick adjustment");
645 SYSCTL_OPAQUE(_kern_ntp, OID_AUTO, default_tick_delta, CTLFLAG_RD,
646 &ntp_default_tick_delta, sizeof(ntp_default_tick_delta), "LU",
647 "default per-tick adjustment");
648 SYSCTL_OPAQUE(_kern_ntp, OID_AUTO, next_leap_second, CTLFLAG_RW,
649 &ntp_leap_second, sizeof(ntp_leap_second), "LU",
651 SYSCTL_INT(_kern_ntp, OID_AUTO, insert_leap_second, CTLFLAG_RW,
652 &ntp_leap_insert, 0, "insert or remove leap second");
653 SYSCTL_PROC(_kern_ntp, OID_AUTO, adjust,
654 CTLTYPE_QUAD|CTLFLAG_RW, 0, 0,
655 sysctl_adjtime, "Q", "relative adjust for delta");
658 * Get value of an interval timer. The process virtual and
659 * profiling virtual time timers are kept in the p_stats area, since
660 * they can be swapped out. These are kept internally in the
661 * way they are specified externally: in time until they expire.
663 * The real time interval timer is kept in the process table slot
664 * for the process, and its value (it_value) is kept as an
665 * absolute time rather than as a delta, so that it is easy to keep
666 * periodic real-time signals from drifting.
668 * Virtual time timers are processed in the hardclock() routine of
669 * kern_clock.c. The real time timer is processed by a timeout
670 * routine, called from the softclock() routine. Since a callout
671 * may be delayed in real time due to interrupt processing in the system,
672 * it is possible for the real time timeout routine (realitexpire, given below),
673 * to be delayed in real time past when it is supposed to occur. It
674 * does not suffice, therefore, to reload the real timer .it_value from the
675 * real time timers .it_interval. Rather, we compute the next time in
676 * absolute time the timer should go off.
680 getitimer(struct getitimer_args *uap)
682 struct proc *p = curproc;
684 struct itimerval aitv;
686 if (uap->which > ITIMER_PROF)
689 if (uap->which == ITIMER_REAL) {
691 * Convert from absolute to relative time in .it_value
692 * part of real time timer. If time for real time timer
693 * has passed return 0, else return difference between
694 * current time and time for the timer to go off.
696 aitv = p->p_realtimer;
697 if (timevalisset(&aitv.it_value)) {
698 getmicrouptime(&ctv);
699 if (timevalcmp(&aitv.it_value, &ctv, <))
700 timevalclear(&aitv.it_value);
702 timevalsub(&aitv.it_value, &ctv);
705 aitv = p->p_stats->p_timer[uap->which];
708 return (copyout((caddr_t)&aitv, (caddr_t)uap->itv,
709 sizeof (struct itimerval)));
714 setitimer(struct setitimer_args *uap)
716 struct itimerval aitv;
718 struct itimerval *itvp;
719 struct proc *p = curproc;
722 if (uap->which > ITIMER_PROF)
725 if (itvp && (error = copyin((caddr_t)itvp, (caddr_t)&aitv,
726 sizeof(struct itimerval))))
728 if ((uap->itv = uap->oitv) &&
729 (error = getitimer((struct getitimer_args *)uap)))
733 if (itimerfix(&aitv.it_value))
735 if (!timevalisset(&aitv.it_value))
736 timevalclear(&aitv.it_interval);
737 else if (itimerfix(&aitv.it_interval))
740 if (uap->which == ITIMER_REAL) {
741 if (timevalisset(&p->p_realtimer.it_value))
742 callout_stop(&p->p_ithandle);
743 if (timevalisset(&aitv.it_value))
744 callout_reset(&p->p_ithandle,
745 tvtohz_high(&aitv.it_value), realitexpire, p);
746 getmicrouptime(&ctv);
747 timevaladd(&aitv.it_value, &ctv);
748 p->p_realtimer = aitv;
750 p->p_stats->p_timer[uap->which] = aitv;
757 * Real interval timer expired:
758 * send process whose timer expired an alarm signal.
759 * If time is not set up to reload, then just return.
760 * Else compute next time timer should go off which is > current time.
761 * This is where delay in processing this timeout causes multiple
762 * SIGALRM calls to be compressed into one.
763 * tvtohz_high() always adds 1 to allow for the time until the next clock
764 * interrupt being strictly less than 1 clock tick, but we don't want
765 * that here since we want to appear to be in sync with the clock
766 * interrupt even when we're delayed.
773 struct timeval ctv, ntv;
775 p = (struct proc *)arg;
777 if (!timevalisset(&p->p_realtimer.it_interval)) {
778 timevalclear(&p->p_realtimer.it_value);
783 timevaladd(&p->p_realtimer.it_value,
784 &p->p_realtimer.it_interval);
785 getmicrouptime(&ctv);
786 if (timevalcmp(&p->p_realtimer.it_value, &ctv, >)) {
787 ntv = p->p_realtimer.it_value;
788 timevalsub(&ntv, &ctv);
789 callout_reset(&p->p_ithandle, tvtohz_low(&ntv),
799 * Check that a proposed value to load into the .it_value or
800 * .it_interval part of an interval timer is acceptable, and
801 * fix it to have at least minimal value (i.e. if it is less
802 * than the resolution of the clock, round it up.)
809 if (tv->tv_sec < 0 || tv->tv_sec > 100000000 ||
810 tv->tv_usec < 0 || tv->tv_usec >= 1000000)
812 if (tv->tv_sec == 0 && tv->tv_usec != 0 && tv->tv_usec < tick)
818 * Decrement an interval timer by a specified number
819 * of microseconds, which must be less than a second,
820 * i.e. < 1000000. If the timer expires, then reload
821 * it. In this case, carry over (usec - old value) to
822 * reduce the value reloaded into the timer so that
823 * the timer does not drift. This routine assumes
824 * that it is called in a context where the timers
825 * on which it is operating cannot change in value.
828 itimerdecr(itp, usec)
829 struct itimerval *itp;
833 if (itp->it_value.tv_usec < usec) {
834 if (itp->it_value.tv_sec == 0) {
835 /* expired, and already in next interval */
836 usec -= itp->it_value.tv_usec;
839 itp->it_value.tv_usec += 1000000;
840 itp->it_value.tv_sec--;
842 itp->it_value.tv_usec -= usec;
844 if (timevalisset(&itp->it_value))
846 /* expired, exactly at end of interval */
848 if (timevalisset(&itp->it_interval)) {
849 itp->it_value = itp->it_interval;
850 itp->it_value.tv_usec -= usec;
851 if (itp->it_value.tv_usec < 0) {
852 itp->it_value.tv_usec += 1000000;
853 itp->it_value.tv_sec--;
856 itp->it_value.tv_usec = 0; /* sec is already 0 */
861 * Add and subtract routines for timevals.
862 * N.B.: subtract routine doesn't deal with
863 * results which are before the beginning,
864 * it just gets very confused in this case.
869 struct timeval *t1, *t2;
872 t1->tv_sec += t2->tv_sec;
873 t1->tv_usec += t2->tv_usec;
879 struct timeval *t1, *t2;
882 t1->tv_sec -= t2->tv_sec;
883 t1->tv_usec -= t2->tv_usec;
892 if (t1->tv_usec < 0) {
894 t1->tv_usec += 1000000;
896 if (t1->tv_usec >= 1000000) {
898 t1->tv_usec -= 1000000;
903 * ratecheck(): simple time-based rate-limit checking.
906 ratecheck(struct timeval *lasttime, const struct timeval *mininterval)
908 struct timeval tv, delta;
911 getmicrouptime(&tv); /* NB: 10ms precision */
913 timevalsub(&delta, lasttime);
916 * check for 0,0 is so that the message will be seen at least once,
917 * even if interval is huge.
919 if (timevalcmp(&delta, mininterval, >=) ||
920 (lasttime->tv_sec == 0 && lasttime->tv_usec == 0)) {
929 * ppsratecheck(): packets (or events) per second limitation.
931 * Return 0 if the limit is to be enforced (e.g. the caller
932 * should drop a packet because of the rate limitation).
934 * maxpps of 0 always causes zero to be returned. maxpps of -1
935 * always causes 1 to be returned; this effectively defeats rate
938 * Note that we maintain the struct timeval for compatibility
939 * with other bsd systems. We reuse the storage and just monitor
940 * clock ticks for minimal overhead.
943 ppsratecheck(struct timeval *lasttime, int *curpps, int maxpps)
948 * Reset the last time and counter if this is the first call
949 * or more than a second has passed since the last update of
953 if (lasttime->tv_sec == 0 || (u_int)(now - lasttime->tv_sec) >= hz) {
954 lasttime->tv_sec = now;
956 return (maxpps != 0);
958 (*curpps)++; /* NB: ignore potential overflow */
959 return (maxpps < 0 || *curpps < maxpps);