freebsd-dev/sys/kern/kern_time.c
Justin T. Gibbs ab36c06737 init_main.c subr_autoconf.c:
Add support for "interrupt driven configuration hooks".
	A component of the kernel can register a hook, most likely
	during auto-configuration, and receive a callback once
	interrupt services are available.  This callback will occur before
	the root and dump devices are configured, so the configuration
	task can affect the selection of those two devices or complete
	any tasks that need to be performed prior to launching init.
	System boot is posponed so long as a hook is registered.  The
	hook owner is responsible for removing the hook once their task
	is complete or the system boot can continue.

kern_acct.c kern_clock.c kern_exit.c kern_synch.c kern_time.c:
	Change the interface and implementation for the kernel callout
	service.  The new implemntaion is based on the work of
	Adam M. Costello and George Varghese, published in a technical
	report entitled "Redesigning the BSD Callout and Timer Facilities".
	The interface used in FreeBSD is a little different than the one
	outlined in the paper.  The new function prototypes are:

	struct callout_handle timeout(void (*func)(void *),
				      void *arg, int ticks);

	void untimeout(void (*func)(void *), void *arg,
		       struct callout_handle handle);

	If a client wishes to remove a timeout, it must store the
	callout_handle returned by timeout and pass it to untimeout.

	The new implementation gives 0(1) insert and removal of callouts
	making this interface scale well even for applications that
	keep 100s of callouts outstanding.

	See the updated timeout.9 man page for more details.
1997-09-21 22:00:25 +00:00

746 lines
19 KiB
C

/*
* Copyright (c) 1982, 1986, 1989, 1993
* The Regents of the University of California. All rights reserved.
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice, this list of conditions and the following disclaimer.
* 2. Redistributions in binary form must reproduce the above copyright
* notice, this list of conditions and the following disclaimer in the
* documentation and/or other materials provided with the distribution.
* 3. All advertising materials mentioning features or use of this software
* must display the following acknowledgement:
* This product includes software developed by the University of
* California, Berkeley and its contributors.
* 4. Neither the name of the University nor the names of its contributors
* may be used to endorse or promote products derived from this software
* without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
* ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
* IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
* ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
* FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
* OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
* HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
* LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
* OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
* SUCH DAMAGE.
*
* @(#)kern_time.c 8.1 (Berkeley) 6/10/93
* $Id: kern_time.c,v 1.34 1997/09/02 20:05:49 bde Exp $
*/
#include <sys/param.h>
#include <sys/sysproto.h>
#include <sys/resourcevar.h>
#include <sys/signalvar.h>
#include <sys/kernel.h>
#include <sys/systm.h>
#include <sys/sysent.h>
#include <sys/proc.h>
#include <sys/time.h>
#include <sys/vnode.h>
#include <vm/vm.h>
#include <vm/vm_extern.h>
struct timezone tz;
/*
* Time of day and interval timer support.
*
* These routines provide the kernel entry points to get and set
* the time-of-day and per-process interval timers. Subroutines
* here provide support for adding and subtracting timeval structures
* and decrementing interval timers, optionally reloading the interval
* timers when they expire.
*/
static int nanosleep1 __P((struct proc *p, struct timespec *rqt,
struct timespec *rmt));
static int settime __P((struct timeval *));
static void timevalfix __P((struct timeval *));
static int
settime(tv)
struct timeval *tv;
{
struct timeval delta;
struct proc *p;
int s;
/*
* Must not set clock backwards in highly secure mode.
*/
s = splclock();
delta.tv_sec = tv->tv_sec - time.tv_sec;
delta.tv_usec = tv->tv_usec - time.tv_usec;
splx(s);
timevalfix(&delta);
if (delta.tv_sec < 0 && securelevel > 1)
return (EPERM);
s = splclock();
/*
* Recalculate delta directly to minimize clock interrupt
* latency. Fix it after the ipl has been lowered.
*/
delta.tv_sec = tv->tv_sec - time.tv_sec;
delta.tv_usec = tv->tv_usec - time.tv_usec;
time = *tv;
/*
* XXX should arrange for microtime() to agree with *tv if
* it is called now. As it is, it may add up to about
* `tick' unwanted usec.
* Another problem is that clock interrupts may occur at
* other than multiples of `tick'. It's not worth fixing
* this here, since the problem is also caused by tick
* adjustments.
*/
(void) splsoftclock();
timevalfix(&delta);
timevaladd(&boottime, &delta);
timevaladd(&runtime, &delta);
for (p = allproc.lh_first; p != 0; p = p->p_list.le_next) {
if (timerisset(&p->p_realtimer.it_value))
timevaladd(&p->p_realtimer.it_value, &delta);
if (p->p_sleepend)
timevaladd(p->p_sleepend, &delta);
}
#ifdef NFS
lease_updatetime(delta.tv_sec);
#endif
splx(s);
resettodr();
return (0);
}
#ifndef _SYS_SYSPROTO_H_
struct clock_gettime_args {
clockid_t clock_id;
struct timespec *tp;
};
#endif
/* ARGSUSED */
int
clock_gettime(p, uap, retval)
struct proc *p;
struct clock_gettime_args *uap;
register_t *retval;
{
struct timeval atv;
struct timespec ats;
if (SCARG(uap, clock_id) != CLOCK_REALTIME)
return (EINVAL);
microtime(&atv);
TIMEVAL_TO_TIMESPEC(&atv, &ats);
return (copyout(&ats, SCARG(uap, tp), sizeof(ats)));
}
#ifndef _SYS_SYSPROTO_H_
struct clock_settime_args {
clockid_t clock_id;
const struct timespec *tp;
};
#endif
/* ARGSUSED */
int
clock_settime(p, uap, retval)
struct proc *p;
struct clock_settime_args *uap;
register_t *retval;
{
struct timeval atv;
struct timespec ats;
int error;
if ((error = suser(p->p_ucred, &p->p_acflag)) != 0)
return (error);
if (SCARG(uap, clock_id) != CLOCK_REALTIME)
return (EINVAL);
if ((error = copyin(SCARG(uap, tp), &ats, sizeof(ats))) != 0)
return (error);
if (ats.tv_nsec < 0 || ats.tv_nsec >= 1000000000)
return (EINVAL);
TIMESPEC_TO_TIMEVAL(&atv, &ats);
if ((error = settime(&atv)))
return (error);
return (0);
}
#ifndef _SYS_SYSPROTO_H_
struct clock_getres_args {
clockid_t clock_id;
struct timespec *tp;
};
#endif
int
clock_getres(p, uap, retval)
struct proc *p;
struct clock_getres_args *uap;
register_t *retval;
{
struct timespec ts;
int error;
if (SCARG(uap, clock_id) != CLOCK_REALTIME)
return (EINVAL);
error = 0;
if (SCARG(uap, tp)) {
ts.tv_sec = 0;
ts.tv_nsec = 1000000000 / hz;
error = copyout(&ts, SCARG(uap, tp), sizeof(ts));
}
return (error);
}
static int nanowait;
static int
nanosleep1(p, rqt, rmt)
struct proc *p;
struct timespec *rqt, *rmt;
{
struct timeval atv, utv, rtv;
int error, s, timo, i, n;
if (rqt->tv_nsec < 0 || rqt->tv_nsec >= 1000000000)
return (EINVAL);
if (rqt->tv_sec < 0 || rqt->tv_sec == 0 && rqt->tv_nsec == 0)
return (0);
TIMESPEC_TO_TIMEVAL(&atv, rqt)
if (itimerfix(&atv)) {
n = atv.tv_sec / 100000000;
rtv = atv;
rtv.tv_sec %= 100000000;
(void)itimerfix(&rtv);
} else
n = 0;
for (i = 0, error = EWOULDBLOCK; i <= n && error == EWOULDBLOCK; i++) {
if (n > 0) {
if (i == n)
atv = rtv;
else {
atv.tv_sec = 100000000;
atv.tv_usec = 0;
}
}
/*
* XXX this is not as careful as settimeofday() about minimising
* interrupt latency. The hzto() interface is inconvenient as usual.
*/
s = splclock();
timevaladd(&atv, &time);
timo = hzto(&atv);
splx(s);
p->p_sleepend = &atv;
error = tsleep(&nanowait, PWAIT | PCATCH, "nanslp", timo);
p->p_sleepend = NULL;
if (error == ERESTART)
error = EINTR;
if (rmt != NULL && (i == n || error != EWOULDBLOCK)) {
/*-
* XXX this is unnecessary and possibly wrong if the timeout
* expired. Then the remaining time should be zero. If the
* calculation gives a nonzero value, then we have a bug.
* (1) if settimeofday() was called, then the calculation is
* probably wrong, since `time' has probably become
* inconsistent with the ending time `atv'.
* XXX (1) should be fixed now with p->p_sleepend;
* (2) otherwise, our calculation of `timo' was wrong, perhaps
* due to `tick' being wrong when hzto() was called or
* changing afterwards (it can be wrong or change due to
* hzto() not knowing about adjtime(2) or tickadj(8)).
* Then we should be sleeping again instead instead of
* returning. Rounding up in hzto() probably fixes this
* problem for small timeouts, but the absolute error may
* be large for large timeouts.
*/
s = splclock();
utv = time;
splx(s);
timevalsub(&atv, &utv);
if (atv.tv_sec < 0)
timerclear(&atv);
if (n > 0)
atv.tv_sec += (n - i) * 100000000;
TIMEVAL_TO_TIMESPEC(&atv, rmt);
}
}
return (error == EWOULDBLOCK ? 0 : error);
}
#ifndef _SYS_SYSPROTO_H_
struct nanosleep_args {
struct timespec *rqtp;
struct timespec *rmtp;
};
#endif
/* ARGSUSED */
int
nanosleep(p, uap, retval)
struct proc *p;
struct nanosleep_args *uap;
register_t *retval;
{
struct timespec rmt, rqt;
int error, error2;
error = copyin(SCARG(uap, rqtp), &rqt, sizeof(rqt));
if (error)
return (error);
if (SCARG(uap, rmtp))
if (!useracc((caddr_t)SCARG(uap, rmtp), sizeof(rmt), B_WRITE))
return (EFAULT);
error = nanosleep1(p, &rqt, &rmt);
if (SCARG(uap, rmtp)) {
error2 = copyout(&rmt, SCARG(uap, rmtp), sizeof(rmt));
if (error2) /* XXX shouldn't happen, did useracc() above */
return (error2);
}
return (error);
}
#ifndef _SYS_SYSPROTO_H_
struct signanosleep_args {
struct timespec *rqtp;
struct timespec *rmtp;
sigset_t *mask;
};
#endif
/* ARGSUSED */
int
signanosleep(p, uap, retval)
struct proc *p;
struct signanosleep_args *uap;
register_t *retval;
{
struct timespec rmt, rqt;
int error, error2;
struct sigacts *ps = p->p_sigacts;
sigset_t mask;
error = copyin(SCARG(uap, rqtp), &rqt, sizeof(rqt));
if (error)
return (error);
if (SCARG(uap, rmtp))
if (!useracc((caddr_t)SCARG(uap, rmtp), sizeof(rmt), B_WRITE))
return (EFAULT);
error = copyin(SCARG(uap, mask), &mask, sizeof(mask));
if (error)
return (error);
/* See kern_sig.c:sigsuspend() for explanation. */
ps->ps_oldmask = p->p_sigmask;
ps->ps_flags |= SAS_OLDMASK;
p->p_sigmask = mask &~ sigcantmask;
error = nanosleep1(p, &rqt, &rmt);
/* See kern_sig.c:sigsuspend() again. */
p->p_sigmask = ps->ps_oldmask; /* in case timeout rather than sig */
ps->ps_flags &= ~SAS_OLDMASK;
if (SCARG(uap, rmtp)) {
error2 = copyout(&rmt, SCARG(uap, rmtp), sizeof(rmt));
if (error2) /* XXX shouldn't happen, did useracc() above */
return (error2);
}
return (error);
}
#ifndef _SYS_SYSPROTO_H_
struct gettimeofday_args {
struct timeval *tp;
struct timezone *tzp;
};
#endif
/* ARGSUSED */
int
gettimeofday(p, uap, retval)
struct proc *p;
register struct gettimeofday_args *uap;
int *retval;
{
struct timeval atv;
int error = 0;
if (uap->tp) {
microtime(&atv);
if ((error = copyout((caddr_t)&atv, (caddr_t)uap->tp,
sizeof (atv))))
return (error);
}
if (uap->tzp)
error = copyout((caddr_t)&tz, (caddr_t)uap->tzp,
sizeof (tz));
return (error);
}
#ifndef _SYS_SYSPROTO_H_
struct settimeofday_args {
struct timeval *tv;
struct timezone *tzp;
};
#endif
/* ARGSUSED */
int
settimeofday(p, uap, retval)
struct proc *p;
struct settimeofday_args *uap;
int *retval;
{
struct timeval atv;
struct timezone atz;
int error;
if ((error = suser(p->p_ucred, &p->p_acflag)))
return (error);
/* Verify all parameters before changing time. */
if (uap->tv) {
if ((error = copyin((caddr_t)uap->tv, (caddr_t)&atv,
sizeof(atv))))
return (error);
if (atv.tv_usec < 0 || atv.tv_usec >= 1000000)
return (EINVAL);
}
if (uap->tzp &&
(error = copyin((caddr_t)uap->tzp, (caddr_t)&atz, sizeof(atz))))
return (error);
if (uap->tv && (error = settime(&atv)))
return (error);
if (uap->tzp)
tz = atz;
return (0);
}
int tickdelta; /* current clock skew, us. per tick */
long timedelta; /* unapplied time correction, us. */
static long bigadj = 1000000; /* use 10x skew above bigadj us. */
#ifndef _SYS_SYSPROTO_H_
struct adjtime_args {
struct timeval *delta;
struct timeval *olddelta;
};
#endif
/* ARGSUSED */
int
adjtime(p, uap, retval)
struct proc *p;
register struct adjtime_args *uap;
int *retval;
{
struct timeval atv;
register long ndelta, ntickdelta, odelta;
int s, error;
if ((error = suser(p->p_ucred, &p->p_acflag)))
return (error);
if ((error =
copyin((caddr_t)uap->delta, (caddr_t)&atv, sizeof(struct timeval))))
return (error);
/*
* Compute the total correction and the rate at which to apply it.
* Round the adjustment down to a whole multiple of the per-tick
* delta, so that after some number of incremental changes in
* hardclock(), tickdelta will become zero, lest the correction
* overshoot and start taking us away from the desired final time.
*/
ndelta = atv.tv_sec * 1000000 + atv.tv_usec;
if (ndelta > bigadj || ndelta < -bigadj)
ntickdelta = 10 * tickadj;
else
ntickdelta = tickadj;
if (ndelta % ntickdelta)
ndelta = ndelta / ntickdelta * ntickdelta;
/*
* To make hardclock()'s job easier, make the per-tick delta negative
* if we want time to run slower; then hardclock can simply compute
* tick + tickdelta, and subtract tickdelta from timedelta.
*/
if (ndelta < 0)
ntickdelta = -ntickdelta;
s = splclock();
odelta = timedelta;
timedelta = ndelta;
tickdelta = ntickdelta;
splx(s);
if (uap->olddelta) {
atv.tv_sec = odelta / 1000000;
atv.tv_usec = odelta % 1000000;
(void) copyout((caddr_t)&atv, (caddr_t)uap->olddelta,
sizeof(struct timeval));
}
return (0);
}
/*
* Get value of an interval timer. The process virtual and
* profiling virtual time timers are kept in the p_stats area, since
* they can be swapped out. These are kept internally in the
* way they are specified externally: in time until they expire.
*
* The real time interval timer is kept in the process table slot
* for the process, and its value (it_value) is kept as an
* absolute time rather than as a delta, so that it is easy to keep
* periodic real-time signals from drifting.
*
* Virtual time timers are processed in the hardclock() routine of
* kern_clock.c. The real time timer is processed by a timeout
* routine, called from the softclock() routine. Since a callout
* may be delayed in real time due to interrupt processing in the system,
* it is possible for the real time timeout routine (realitexpire, given below),
* to be delayed in real time past when it is supposed to occur. It
* does not suffice, therefore, to reload the real timer .it_value from the
* real time timers .it_interval. Rather, we compute the next time in
* absolute time the timer should go off.
*/
#ifndef _SYS_SYSPROTO_H_
struct getitimer_args {
u_int which;
struct itimerval *itv;
};
#endif
/* ARGSUSED */
int
getitimer(p, uap, retval)
struct proc *p;
register struct getitimer_args *uap;
int *retval;
{
struct itimerval aitv;
int s;
if (uap->which > ITIMER_PROF)
return (EINVAL);
s = splclock();
if (uap->which == ITIMER_REAL) {
/*
* Convert from absoulte to relative time in .it_value
* part of real time timer. If time for real time timer
* has passed return 0, else return difference between
* current time and time for the timer to go off.
*/
aitv = p->p_realtimer;
if (timerisset(&aitv.it_value))
if (timercmp(&aitv.it_value, &time, <))
timerclear(&aitv.it_value);
else
timevalsub(&aitv.it_value, &time);
} else
aitv = p->p_stats->p_timer[uap->which];
splx(s);
return (copyout((caddr_t)&aitv, (caddr_t)uap->itv,
sizeof (struct itimerval)));
}
#ifndef _SYS_SYSPROTO_H_
struct setitimer_args {
u_int which;
struct itimerval *itv, *oitv;
};
#endif
/* ARGSUSED */
int
setitimer(p, uap, retval)
struct proc *p;
register struct setitimer_args *uap;
int *retval;
{
struct itimerval aitv;
register struct itimerval *itvp;
int s, error;
if (uap->which > ITIMER_PROF)
return (EINVAL);
itvp = uap->itv;
if (itvp && (error = copyin((caddr_t)itvp, (caddr_t)&aitv,
sizeof(struct itimerval))))
return (error);
if ((uap->itv = uap->oitv) &&
(error = getitimer(p, (struct getitimer_args *)uap, retval)))
return (error);
if (itvp == 0)
return (0);
if (itimerfix(&aitv.it_value))
return (EINVAL);
if (!timerisset(&aitv.it_value))
timerclear(&aitv.it_interval);
else if (itimerfix(&aitv.it_interval))
return (EINVAL);
s = splclock();
if (uap->which == ITIMER_REAL) {
if (timerisset(&p->p_realtimer.it_value))
untimeout(realitexpire, (caddr_t)p, p->p_ithandle);
if (timerisset(&aitv.it_value)) {
timevaladd(&aitv.it_value, &time);
p->p_ithandle = timeout(realitexpire, (caddr_t)p,
hzto(&aitv.it_value));
}
p->p_realtimer = aitv;
} else
p->p_stats->p_timer[uap->which] = aitv;
splx(s);
return (0);
}
/*
* Real interval timer expired:
* send process whose timer expired an alarm signal.
* If time is not set up to reload, then just return.
* Else compute next time timer should go off which is > current time.
* This is where delay in processing this timeout causes multiple
* SIGALRM calls to be compressed into one.
* hzto() always adds 1 to allow for the time until the next clock
* interrupt being strictly less than 1 clock tick, but we don't want
* that here since we want to appear to be in sync with the clock
* interrupt even when we're delayed.
*/
void
realitexpire(arg)
void *arg;
{
register struct proc *p;
int s;
p = (struct proc *)arg;
psignal(p, SIGALRM);
if (!timerisset(&p->p_realtimer.it_interval)) {
timerclear(&p->p_realtimer.it_value);
return;
}
for (;;) {
s = splclock();
timevaladd(&p->p_realtimer.it_value,
&p->p_realtimer.it_interval);
if (timercmp(&p->p_realtimer.it_value, &time, >)) {
p->p_ithandle =
timeout(realitexpire, (caddr_t)p,
hzto(&p->p_realtimer.it_value) - 1);
splx(s);
return;
}
splx(s);
}
}
/*
* Check that a proposed value to load into the .it_value or
* .it_interval part of an interval timer is acceptable, and
* fix it to have at least minimal value (i.e. if it is less
* than the resolution of the clock, round it up.)
*/
int
itimerfix(tv)
struct timeval *tv;
{
if (tv->tv_sec < 0 || tv->tv_sec > 100000000 ||
tv->tv_usec < 0 || tv->tv_usec >= 1000000)
return (EINVAL);
if (tv->tv_sec == 0 && tv->tv_usec != 0 && tv->tv_usec < tick)
tv->tv_usec = tick;
return (0);
}
/*
* Decrement an interval timer by a specified number
* of microseconds, which must be less than a second,
* i.e. < 1000000. If the timer expires, then reload
* it. In this case, carry over (usec - old value) to
* reduce the value reloaded into the timer so that
* the timer does not drift. This routine assumes
* that it is called in a context where the timers
* on which it is operating cannot change in value.
*/
int
itimerdecr(itp, usec)
register struct itimerval *itp;
int usec;
{
if (itp->it_value.tv_usec < usec) {
if (itp->it_value.tv_sec == 0) {
/* expired, and already in next interval */
usec -= itp->it_value.tv_usec;
goto expire;
}
itp->it_value.tv_usec += 1000000;
itp->it_value.tv_sec--;
}
itp->it_value.tv_usec -= usec;
usec = 0;
if (timerisset(&itp->it_value))
return (1);
/* expired, exactly at end of interval */
expire:
if (timerisset(&itp->it_interval)) {
itp->it_value = itp->it_interval;
itp->it_value.tv_usec -= usec;
if (itp->it_value.tv_usec < 0) {
itp->it_value.tv_usec += 1000000;
itp->it_value.tv_sec--;
}
} else
itp->it_value.tv_usec = 0; /* sec is already 0 */
return (0);
}
/*
* Add and subtract routines for timevals.
* N.B.: subtract routine doesn't deal with
* results which are before the beginning,
* it just gets very confused in this case.
* Caveat emptor.
*/
void
timevaladd(t1, t2)
struct timeval *t1, *t2;
{
t1->tv_sec += t2->tv_sec;
t1->tv_usec += t2->tv_usec;
timevalfix(t1);
}
void
timevalsub(t1, t2)
struct timeval *t1, *t2;
{
t1->tv_sec -= t2->tv_sec;
t1->tv_usec -= t2->tv_usec;
timevalfix(t1);
}
static void
timevalfix(t1)
struct timeval *t1;
{
if (t1->tv_usec < 0) {
t1->tv_sec--;
t1->tv_usec += 1000000;
}
if (t1->tv_usec >= 1000000) {
t1->tv_sec++;
t1->tv_usec -= 1000000;
}
}