NetBSD/sys/kern/kern_ntptime.c
jonathan e7ef034c05 Add NTP kernel precision timekeeping from Dave Mill's xntp distribution
and the "kernel.tar.Z" distribution on louie.udel.edu, which is older than
xntp 3.4y or 3.5a, but contains newer kernel source fragments.

This commit adds support for a new kernel configuration option, NTP.
If NTP is selected, then the system clock should be run at "HZ", which
must be defined at compile time to be one value from:
  60, 64, 100, 128, 256, 512, 1024.

Powers of 2 are ideal; 60 and 100 are supported but are marginally less
accurate.

If NTP is not configured, there should be no change in behavior relative
to pre-NTP kernels.

These changes have been tested extensively with xntpd 3.4y on a decstation;
almost identical kernel mods work on an i386.  No pulse-per-second (PPS)
line discipline support is included, due to unavailability of hardware
to test it.

With this in-kernel PLL support for NetBSD, both xntp 3.4y and xntp
3.5a user-level code need minor changes. xntp's prototype for
syscall() is  correct for FreeBSD, but not for NetBSD.
1996-02-27 04:20:30 +00:00

405 lines
11 KiB
C

/* $NetBSD: kern_ntptime.c,v 1.1 1996/02/27 04:20:38 jonathan Exp $ */
/******************************************************************************
* *
* Copyright (c) David L. Mills 1993, 1994 *
* *
* Permission to use, copy, modify, and distribute this software and its *
* documentation for any purpose and without fee is hereby granted, provided *
* that the above copyright notice appears in all copies and that both the *
* copyright notice and this permission notice appear in supporting *
* documentation, and that the name University of Delaware not be used in *
* advertising or publicity pertaining to distribution of the software *
* without specific, written prior permission. The University of Delaware *
* makes no representations about the suitability this software for any *
* purpose. It is provided "as is" without express or implied warranty. *
* *
******************************************************************************/
/*
* Modification history kern_ntptime.c
*
* 24 Sep 94 David L. Mills
* Tightened code at exits.
*
* 24 Mar 94 David L. Mills
* Revised syscall interface to include new variables for PPS
* time discipline.
*
* 14 Feb 94 David L. Mills
* Added code for external clock
*
* 28 Nov 93 David L. Mills
* Revised frequency scaling to conform with adjusted parameters
*
* 17 Sep 93 David L. Mills
* Created file
*/
/*
* ntp_gettime(), ntp_adjtime() - precision time interface for SunOS
* V4.1.1 and V4.1.3
*
* These routines consitute the Network Time Protocol (NTP) interfaces
* for user and daemon application programs. The ntp_gettime() routine
* provides the time, maximum error (synch distance) and estimated error
* (dispersion) to client user application programs. The ntp_adjtime()
* routine is used by the NTP daemon to adjust the system clock to an
* externally derived time. The time offset and related variables set by
* this routine are used by hardclock() to adjust the phase and
* frequency of the phase-lock loop which controls the system clock.
*/
#include <sys/param.h>
#include <sys/resourcevar.h>
#include <sys/systm.h>
#include <sys/kernel.h>
#include <sys/proc.h>
#include <sys/timex.h>
#include <sys/vnode.h>
#include <sys/mount.h>
#include <sys/syscallargs.h>
#include <machine/cpu.h>
#ifdef NTP
/*
* The following variables are used by the hardclock() routine in the
* kern_clock.c module and are described in that module.
*/
extern struct timeval time; /* kernel time variable */
extern int time_state; /* clock state */
extern int time_status; /* clock status bits */
extern long time_offset; /* time adjustment (us) */
extern long time_freq; /* frequency offset (scaled ppm) */
extern long time_maxerror; /* maximum error (us) */
extern long time_esterror; /* estimated error (us) */
extern long time_constant; /* pll time constant */
extern long time_precision; /* clock precision (us) */
extern long time_tolerance; /* frequency tolerance (scaled ppm) */
#ifdef PPS_SYNC
/*
* The following variables are used only if the PPS signal discipline
* is configured in the kernel.
*/
extern int pps_shift; /* interval duration (s) (shift) */
extern long pps_freq; /* pps frequency offset (scaled ppm) */
extern long pps_jitter; /* pps jitter (us) */
extern long pps_stabil; /* pps stability (scaled ppm) */
extern long pps_jitcnt; /* jitter limit exceeded */
extern long pps_calcnt; /* calibration intervals */
extern long pps_errcnt; /* calibration errors */
extern long pps_stbcnt; /* stability limit exceeded */
#endif /* PPS_SYNC */
/*ARGSUSED*/
/*
* ntp_gettime() - NTP user application interface
*/
int
ntp_gettime(p, v, retval)
struct proc *p;
void *v;
register_t *retval;
{
struct ntp_gettime_args /* {
syscallarg(struct timex *) tp;
} */ *uap = v;
struct timeval atv;
struct ntptimeval ntv;
int error = 0;
int s;
if (SCARG(uap, tp)) {
s = splclock();
#ifdef EXT_CLOCK
/*
* The microtime() external clock routine returns a
* status code. If less than zero, we declare an error
* in the clock status word and return the kernel
* (software) time variable. While there are other
* places that call microtime(), this is the only place
* that matters from an application point of view.
*/
if (microtime(&atv) < 0) {
time_status |= STA_CLOCKERR;
ntv.time = time;
} else
time_status &= ~STA_CLOCKERR;
#else /* EXT_CLOCK */
microtime(&atv);
#endif /* EXT_CLOCK */
ntv.time = atv;
ntv.maxerror = time_maxerror;
ntv.esterror = time_esterror;
(void) splx(s);
error = copyout((caddr_t)&ntv, (caddr_t)SCARG(uap, tp),
sizeof (ntv));
}
if (!error) {
/*
* Status word error decode. If any of these conditions
* occur, an error is returned, instead of the status
* word. Most applications will care only about the fact
* the system clock may not be trusted, not about the
* details.
*
* Hardware or software error
*/
if ((time_status & (STA_UNSYNC | STA_CLOCKERR)) ||
/*
* PPS signal lost when either time or frequency
* synchronization requested
*/
(time_status & (STA_PPSFREQ | STA_PPSTIME) &&
!(time_status & STA_PPSSIGNAL)) ||
/*
* PPS jitter exceeded when time synchronization
* requested
*/
(time_status & STA_PPSTIME &&
time_status & STA_PPSJITTER) ||
/*
* PPS wander exceeded or calibration error when
* frequency synchronization requested
*/
(time_status & STA_PPSFREQ &&
time_status & (STA_PPSWANDER | STA_PPSERROR)))
*retval = TIME_ERROR;
else
*retval = (register_t)time_state;
}
return(error);
}
/* ARGSUSED */
/*
* ntp_adjtime() - NTP daemon application interface
*/
int
ntp_adjtime(p, v, retval)
struct proc *p;
void *v;
register_t *retval;
{
struct ntp_adjtime_args /* {
syscallarg(struct timex *) tp;
} */ *uap = v;
struct timex ntv;
int error = 0;
int modes;
int s;
if ((error = copyin((caddr_t)SCARG(uap, tp), (caddr_t)&ntv,
sizeof(ntv))))
return (error);
/*
* Update selected clock variables - only the superuser can
* change anything. Note that there is no error checking here on
* the assumption the superuser should know what it is doing.
*/
modes = ntv.modes;
if (modes != 0 && (error = suser(p->p_ucred, &p->p_acflag)))
return (error);
s = splclock();
if (modes & MOD_FREQUENCY)
#ifdef PPS_SYNC
time_freq = ntv.freq - pps_freq;
#else /* PPS_SYNC */
time_freq = ntv.freq;
#endif /* PPS_SYNC */
if (modes & MOD_MAXERROR)
time_maxerror = ntv.maxerror;
if (modes & MOD_ESTERROR)
time_esterror = ntv.esterror;
if (modes & MOD_STATUS) {
time_status &= STA_RONLY;
time_status |= ntv.status & ~STA_RONLY;
}
if (modes & MOD_TIMECONST)
time_constant = ntv.constant;
if (modes & MOD_OFFSET)
hardupdate(ntv.offset);
/*
* Retrieve all clock variables
*/
if (time_offset < 0)
ntv.offset = -(-time_offset >> SHIFT_UPDATE);
else
ntv.offset = time_offset >> SHIFT_UPDATE;
#ifdef PPS_SYNC
ntv.freq = time_freq + pps_freq;
#else /* PPS_SYNC */
ntv.freq = time_freq;
#endif /* PPS_SYNC */
ntv.maxerror = time_maxerror;
ntv.esterror = time_esterror;
ntv.status = time_status;
ntv.constant = time_constant;
ntv.precision = time_precision;
ntv.tolerance = time_tolerance;
#ifdef PPS_SYNC
ntv.shift = pps_shift;
ntv.ppsfreq = pps_freq;
ntv.jitter = pps_jitter >> PPS_AVG;
ntv.stabil = pps_stabil;
ntv.calcnt = pps_calcnt;
ntv.errcnt = pps_errcnt;
ntv.jitcnt = pps_jitcnt;
ntv.stbcnt = pps_stbcnt;
#endif /* PPS_SYNC */
(void)splx(s);
error = copyout((caddr_t)&ntv, (caddr_t)SCARG(uap, tp), sizeof(ntv));
if (!error) {
/*
* Status word error decode. See comments in
* ntp_gettime() routine.
*/
if ((time_status & (STA_UNSYNC | STA_CLOCKERR)) ||
(time_status & (STA_PPSFREQ | STA_PPSTIME) &&
!(time_status & STA_PPSSIGNAL)) ||
(time_status & STA_PPSTIME &&
time_status & STA_PPSJITTER) ||
(time_status & STA_PPSFREQ &&
time_status & (STA_PPSWANDER | STA_PPSERROR)))
*retval = TIME_ERROR;
else
*retval = (register_t)time_state;
}
return error;
}
/*
* return information about kernel precision timekeeping
*/
int
sysctl_ntptime(where, sizep)
register char *where;
size_t *sizep;
{
struct timeval atv;
struct ntptimeval ntv;
int s;
/*
* Construct ntp_timeval.
*/
s = splclock();
#ifdef EXT_CLOCK
/*
* The microtime() external clock routine returns a
* status code. If less than zero, we declare an error
* in the clock status word and return the kernel
* (software) time variable. While there are other
* places that call microtime(), this is the only place
* that matters from an application point of view.
*/
if (microtime(&atv) < 0) {
time_status |= STA_CLOCKERR;
ntv.time = time;
} else {
time_status &= ~STA_CLOCKERR;
}
#else /* EXT_CLOCK */
microtime(&atv);
#endif /* EXT_CLOCK */
ntv.time = atv;
ntv.maxerror = time_maxerror;
ntv.esterror = time_esterror;
splx(s);
#ifdef notyet
/*
* Status word error decode. If any of these conditions
* occur, an error is returned, instead of the status
* word. Most applications will care only about the fact
* the system clock may not be trusted, not about the
* details.
*
* Hardware or software error
*/
if ((time_status & (STA_UNSYNC | STA_CLOCKERR)) ||
ntv.time_state = TIME_ERROR;
/*
* PPS signal lost when either time or frequency
* synchronization requested
*/
(time_status & (STA_PPSFREQ | STA_PPSTIME) &&
!(time_status & STA_PPSSIGNAL)) ||
/*
* PPS jitter exceeded when time synchronization
* requested
*/
(time_status & STA_PPSTIME &&
time_status & STA_PPSJITTER) ||
/*
* PPS wander exceeded or calibration error when
* frequency synchronization requested
*/
(time_status & STA_PPSFREQ &&
time_status & (STA_PPSWANDER | STA_PPSERROR)))
ntv.time_state = TIME_ERROR;
else
ntv.time_state = time_state;
#endif /* notyet */
return (sysctl_rdstruct(where, sizep, NULL, &ntv, sizeof(ntv)));
}
#else /* !NTP */
/*
* For kernels configured without the NTP option, emulate the behavior
* of a kernel with no NTP support (i.e., sys_nosys()). On systems
* where kernel NTP support appears present when xntpd is compiled,
* (e.g., sys/timex.h is present), xntpd relies on getting a SIGSYS
* signal in response to an ntp_adjtime() syscal, to inform xntpd that
* NTP support is not really present, and xntpd should fall back to
* using a user-level phase-locked loop to discipline the clock.
*/
int
ntp_gettime(p, v, retval)
struct proc *p;
void *v;
register_t *retval;
{
return(ENOSYS);
}
int
ntp_adjtime(p, v, retval)
struct proc *p;
void *v;
register_t *retval;
{
return(sys_nosys(p, v, retval));
}
int
sysctl_ntptime(where, sizep)
register char *where;
size_t *sizep;
{
return (ENOSYS);
}
#endif /* NTP */