1048 lines
31 KiB
C
1048 lines
31 KiB
C
/*-
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***********************************************************************
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* *
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* Copyright (c) David L. Mills 1993-2001 *
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* *
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* Permission to use, copy, modify, and distribute this software and *
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* its documentation for any purpose and without fee is hereby *
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* granted, provided that the above copyright notice appears in all *
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* copies and that both the copyright notice and this permission *
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* notice appear in supporting documentation, and that the name *
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* University of Delaware not be used in advertising or publicity *
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* pertaining to distribution of the software without specific, *
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* written prior permission. The University of Delaware makes no *
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* representations about the suitability this software for any *
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* purpose. It is provided "as is" without express or implied *
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* warranty. *
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* *
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**********************************************************************/
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/*
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* Adapted from the original sources for FreeBSD and timecounters by:
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* Poul-Henning Kamp <phk@FreeBSD.org>.
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*
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* The 32bit version of the "LP" macros seems a bit past its "sell by"
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* date so I have retained only the 64bit version and included it directly
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* in this file.
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*
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* Only minor changes done to interface with the timecounters over in
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* sys/kern/kern_clock.c. Some of the comments below may be (even more)
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* confusing and/or plain wrong in that context.
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*/
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#include <sys/cdefs.h>
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#include "opt_ntp.h"
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/sysproto.h>
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#include <sys/eventhandler.h>
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#include <sys/kernel.h>
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#include <sys/priv.h>
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#include <sys/proc.h>
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#include <sys/lock.h>
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#include <sys/mutex.h>
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#include <sys/time.h>
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#include <sys/timex.h>
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#include <sys/timetc.h>
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#include <sys/timepps.h>
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#include <sys/syscallsubr.h>
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#include <sys/sysctl.h>
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#ifdef PPS_SYNC
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FEATURE(pps_sync, "Support usage of external PPS signal by kernel PLL");
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#endif
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/*
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* Single-precision macros for 64-bit machines
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*/
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typedef int64_t l_fp;
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#define L_ADD(v, u) ((v) += (u))
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#define L_SUB(v, u) ((v) -= (u))
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#define L_ADDHI(v, a) ((v) += (int64_t)(a) << 32)
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#define L_NEG(v) ((v) = -(v))
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#define L_RSHIFT(v, n) \
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do { \
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if ((v) < 0) \
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(v) = -(-(v) >> (n)); \
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else \
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(v) = (v) >> (n); \
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} while (0)
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#define L_MPY(v, a) ((v) *= (a))
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#define L_CLR(v) ((v) = 0)
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#define L_ISNEG(v) ((v) < 0)
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#define L_LINT(v, a) \
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do { \
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if ((a) < 0) \
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((v) = -((int64_t)(-(a)) << 32)); \
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else \
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((v) = (int64_t)(a) << 32); \
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} while (0)
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#define L_GINT(v) ((v) < 0 ? -(-(v) >> 32) : (v) >> 32)
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/*
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* Generic NTP kernel interface
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*
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* These routines constitute the Network Time Protocol (NTP) interfaces
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* for user and daemon application programs. The ntp_gettime() routine
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* provides the time, maximum error (synch distance) and estimated error
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* (dispersion) to client user application programs. The ntp_adjtime()
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* routine is used by the NTP daemon to adjust the system clock to an
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* externally derived time. The time offset and related variables set by
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* this routine are used by other routines in this module to adjust the
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* phase and frequency of the clock discipline loop which controls the
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* system clock.
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*
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* When the kernel time is reckoned directly in nanoseconds (NTP_NANO
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* defined), the time at each tick interrupt is derived directly from
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* the kernel time variable. When the kernel time is reckoned in
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* microseconds, (NTP_NANO undefined), the time is derived from the
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* kernel time variable together with a variable representing the
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* leftover nanoseconds at the last tick interrupt. In either case, the
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* current nanosecond time is reckoned from these values plus an
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* interpolated value derived by the clock routines in another
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* architecture-specific module. The interpolation can use either a
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* dedicated counter or a processor cycle counter (PCC) implemented in
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* some architectures.
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*
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* Note that all routines must run at priority splclock or higher.
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*/
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/*
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* Phase/frequency-lock loop (PLL/FLL) definitions
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*
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* The nanosecond clock discipline uses two variable types, time
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* variables and frequency variables. Both types are represented as 64-
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* bit fixed-point quantities with the decimal point between two 32-bit
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* halves. On a 32-bit machine, each half is represented as a single
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* word and mathematical operations are done using multiple-precision
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* arithmetic. On a 64-bit machine, ordinary computer arithmetic is
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* used.
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*
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* A time variable is a signed 64-bit fixed-point number in ns and
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* fraction. It represents the remaining time offset to be amortized
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* over succeeding tick interrupts. The maximum time offset is about
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* 0.5 s and the resolution is about 2.3e-10 ns.
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*
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* 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
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* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
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* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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* |s s s| ns |
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* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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* | fraction |
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* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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*
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* A frequency variable is a signed 64-bit fixed-point number in ns/s
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* and fraction. It represents the ns and fraction to be added to the
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* kernel time variable at each second. The maximum frequency offset is
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* about +-500000 ns/s and the resolution is about 2.3e-10 ns/s.
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*
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* 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3
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* 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
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* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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* |s s s s s s s s s s s s s| ns/s |
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* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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* | fraction |
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* +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
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*/
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/*
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* The following variables establish the state of the PLL/FLL and the
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* residual time and frequency offset of the local clock.
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*/
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#define SHIFT_PLL 4 /* PLL loop gain (shift) */
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#define SHIFT_FLL 2 /* FLL loop gain (shift) */
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static int time_state = TIME_OK; /* clock state */
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int time_status = STA_UNSYNC; /* clock status bits */
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static long time_tai; /* TAI offset (s) */
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static long time_monitor; /* last time offset scaled (ns) */
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static long time_constant; /* poll interval (shift) (s) */
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static long time_precision = 1; /* clock precision (ns) */
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static long time_maxerror = MAXPHASE / 1000; /* maximum error (us) */
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long time_esterror = MAXPHASE / 1000; /* estimated error (us) */
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static long time_reftime; /* uptime at last adjustment (s) */
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static l_fp time_offset; /* time offset (ns) */
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static l_fp time_freq; /* frequency offset (ns/s) */
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static l_fp time_adj; /* tick adjust (ns/s) */
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static int64_t time_adjtime; /* correction from adjtime(2) (usec) */
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static struct mtx ntp_lock;
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MTX_SYSINIT(ntp, &ntp_lock, "ntp", MTX_SPIN);
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#define NTP_LOCK() mtx_lock_spin(&ntp_lock)
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#define NTP_UNLOCK() mtx_unlock_spin(&ntp_lock)
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#define NTP_ASSERT_LOCKED() mtx_assert(&ntp_lock, MA_OWNED)
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#ifdef PPS_SYNC
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/*
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* The following variables are used when a pulse-per-second (PPS) signal
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* is available and connected via a modem control lead. They establish
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* the engineering parameters of the clock discipline loop when
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* controlled by the PPS signal.
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*/
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#define PPS_FAVG 2 /* min freq avg interval (s) (shift) */
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#define PPS_FAVGDEF 8 /* default freq avg int (s) (shift) */
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#define PPS_FAVGMAX 15 /* max freq avg interval (s) (shift) */
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#define PPS_PAVG 4 /* phase avg interval (s) (shift) */
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#define PPS_VALID 120 /* PPS signal watchdog max (s) */
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#define PPS_MAXWANDER 100000 /* max PPS wander (ns/s) */
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#define PPS_POPCORN 2 /* popcorn spike threshold (shift) */
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static struct timespec pps_tf[3]; /* phase median filter */
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static l_fp pps_freq; /* scaled frequency offset (ns/s) */
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static long pps_fcount; /* frequency accumulator */
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static long pps_jitter; /* nominal jitter (ns) */
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static long pps_stabil; /* nominal stability (scaled ns/s) */
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static long pps_lastsec; /* time at last calibration (s) */
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static int pps_valid; /* signal watchdog counter */
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static int pps_shift = PPS_FAVG; /* interval duration (s) (shift) */
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static int pps_shiftmax = PPS_FAVGDEF; /* max interval duration (s) (shift) */
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static int pps_intcnt; /* wander counter */
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/*
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* PPS signal quality monitors
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*/
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static long pps_calcnt; /* calibration intervals */
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static long pps_jitcnt; /* jitter limit exceeded */
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static long pps_stbcnt; /* stability limit exceeded */
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static long pps_errcnt; /* calibration errors */
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#endif /* PPS_SYNC */
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/*
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* End of phase/frequency-lock loop (PLL/FLL) definitions
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*/
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static void hardupdate(long offset);
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static void ntp_gettime1(struct ntptimeval *ntvp);
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static bool ntp_is_time_error(int tsl);
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static bool
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ntp_is_time_error(int tsl)
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{
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/*
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* Status word error decode. If any of these conditions occur,
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* an error is returned, instead of the status word. Most
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* applications will care only about the fact the system clock
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* may not be trusted, not about the details.
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*
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* Hardware or software error
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*/
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if ((tsl & (STA_UNSYNC | STA_CLOCKERR)) ||
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/*
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* PPS signal lost when either time or frequency synchronization
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* requested
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*/
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(tsl & (STA_PPSFREQ | STA_PPSTIME) &&
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!(tsl & STA_PPSSIGNAL)) ||
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/*
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* PPS jitter exceeded when time synchronization requested
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*/
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(tsl & STA_PPSTIME && tsl & STA_PPSJITTER) ||
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/*
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* PPS wander exceeded or calibration error when frequency
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* synchronization requested
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*/
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(tsl & STA_PPSFREQ &&
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tsl & (STA_PPSWANDER | STA_PPSERROR)))
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return (true);
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return (false);
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}
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static void
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ntp_gettime1(struct ntptimeval *ntvp)
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{
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struct timespec atv; /* nanosecond time */
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NTP_ASSERT_LOCKED();
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nanotime(&atv);
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ntvp->time.tv_sec = atv.tv_sec;
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ntvp->time.tv_nsec = atv.tv_nsec;
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ntvp->maxerror = time_maxerror;
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ntvp->esterror = time_esterror;
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ntvp->tai = time_tai;
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ntvp->time_state = time_state;
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if (ntp_is_time_error(time_status))
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ntvp->time_state = TIME_ERROR;
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}
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/*
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* ntp_gettime() - NTP user application interface
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*
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* See the timex.h header file for synopsis and API description. Note that
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* the TAI offset is returned in the ntvtimeval.tai structure member.
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*/
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#ifndef _SYS_SYSPROTO_H_
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struct ntp_gettime_args {
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struct ntptimeval *ntvp;
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};
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#endif
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/* ARGSUSED */
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int
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sys_ntp_gettime(struct thread *td, struct ntp_gettime_args *uap)
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{
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struct ntptimeval ntv;
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memset(&ntv, 0, sizeof(ntv));
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NTP_LOCK();
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ntp_gettime1(&ntv);
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NTP_UNLOCK();
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td->td_retval[0] = ntv.time_state;
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return (copyout(&ntv, uap->ntvp, sizeof(ntv)));
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}
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static int
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ntp_sysctl(SYSCTL_HANDLER_ARGS)
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{
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struct ntptimeval ntv; /* temporary structure */
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memset(&ntv, 0, sizeof(ntv));
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NTP_LOCK();
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ntp_gettime1(&ntv);
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NTP_UNLOCK();
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return (sysctl_handle_opaque(oidp, &ntv, sizeof(ntv), req));
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}
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SYSCTL_NODE(_kern, OID_AUTO, ntp_pll, CTLFLAG_RW | CTLFLAG_MPSAFE, 0,
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"");
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SYSCTL_PROC(_kern_ntp_pll, OID_AUTO, gettime, CTLTYPE_OPAQUE | CTLFLAG_RD |
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CTLFLAG_MPSAFE, 0, sizeof(struct ntptimeval) , ntp_sysctl, "S,ntptimeval",
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"");
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#ifdef PPS_SYNC
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SYSCTL_INT(_kern_ntp_pll, OID_AUTO, pps_shiftmax, CTLFLAG_RW,
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&pps_shiftmax, 0, "Max interval duration (sec) (shift)");
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SYSCTL_INT(_kern_ntp_pll, OID_AUTO, pps_shift, CTLFLAG_RW,
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&pps_shift, 0, "Interval duration (sec) (shift)");
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SYSCTL_LONG(_kern_ntp_pll, OID_AUTO, time_monitor, CTLFLAG_RD,
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&time_monitor, 0, "Last time offset scaled (ns)");
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SYSCTL_S64(_kern_ntp_pll, OID_AUTO, pps_freq, CTLFLAG_RD | CTLFLAG_MPSAFE,
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&pps_freq, 0,
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"Scaled frequency offset (ns/sec)");
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SYSCTL_S64(_kern_ntp_pll, OID_AUTO, time_freq, CTLFLAG_RD | CTLFLAG_MPSAFE,
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&time_freq, 0,
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"Frequency offset (ns/sec)");
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#endif
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/*
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* ntp_adjtime() - NTP daemon application interface
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*
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* See the timex.h header file for synopsis and API description. Note that
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* the timex.constant structure member has a dual purpose to set the time
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* constant and to set the TAI offset.
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*/
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int
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kern_ntp_adjtime(struct thread *td, struct timex *ntv, int *retvalp)
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{
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long freq; /* frequency ns/s) */
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int modes; /* mode bits from structure */
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int error, retval;
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/*
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* Update selected clock variables - only the superuser can
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* change anything. Note that there is no error checking here on
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* the assumption the superuser should know what it is doing.
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* Note that either the time constant or TAI offset are loaded
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* from the ntv.constant member, depending on the mode bits. If
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* the STA_PLL bit in the status word is cleared, the state and
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* status words are reset to the initial values at boot.
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*/
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modes = ntv->modes;
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error = 0;
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if (modes)
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error = priv_check(td, PRIV_NTP_ADJTIME);
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if (error != 0)
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return (error);
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NTP_LOCK();
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if (modes & MOD_MAXERROR)
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time_maxerror = ntv->maxerror;
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if (modes & MOD_ESTERROR)
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time_esterror = ntv->esterror;
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if (modes & MOD_STATUS) {
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if (time_status & STA_PLL && !(ntv->status & STA_PLL)) {
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time_state = TIME_OK;
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time_status = STA_UNSYNC;
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#ifdef PPS_SYNC
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pps_shift = PPS_FAVG;
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#endif /* PPS_SYNC */
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}
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time_status &= STA_RONLY;
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time_status |= ntv->status & ~STA_RONLY;
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}
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if (modes & MOD_TIMECONST) {
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if (ntv->constant < 0)
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time_constant = 0;
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else if (ntv->constant > MAXTC)
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time_constant = MAXTC;
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else
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time_constant = ntv->constant;
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}
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if (modes & MOD_TAI) {
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if (ntv->constant > 0) /* XXX zero & negative numbers ? */
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time_tai = ntv->constant;
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}
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#ifdef PPS_SYNC
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if (modes & MOD_PPSMAX) {
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if (ntv->shift < PPS_FAVG)
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pps_shiftmax = PPS_FAVG;
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else if (ntv->shift > PPS_FAVGMAX)
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pps_shiftmax = PPS_FAVGMAX;
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else
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pps_shiftmax = ntv->shift;
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}
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#endif /* PPS_SYNC */
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if (modes & MOD_NANO)
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time_status |= STA_NANO;
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if (modes & MOD_MICRO)
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time_status &= ~STA_NANO;
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if (modes & MOD_CLKB)
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time_status |= STA_CLK;
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if (modes & MOD_CLKA)
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time_status &= ~STA_CLK;
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if (modes & MOD_FREQUENCY) {
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freq = (ntv->freq * 1000LL) >> 16;
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if (freq > MAXFREQ)
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L_LINT(time_freq, MAXFREQ);
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else if (freq < -MAXFREQ)
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L_LINT(time_freq, -MAXFREQ);
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else {
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/*
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* ntv->freq is [PPM * 2^16] = [us/s * 2^16]
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* time_freq is [ns/s * 2^32]
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*/
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time_freq = ntv->freq * 1000LL * 65536LL;
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}
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#ifdef PPS_SYNC
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pps_freq = time_freq;
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#endif /* PPS_SYNC */
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}
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if (modes & MOD_OFFSET) {
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if (time_status & STA_NANO)
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hardupdate(ntv->offset);
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else
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hardupdate(ntv->offset * 1000);
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}
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/*
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* Retrieve all clock variables. Note that the TAI offset is
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* returned only by ntp_gettime();
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*/
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if (time_status & STA_NANO)
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ntv->offset = L_GINT(time_offset);
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else
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ntv->offset = L_GINT(time_offset) / 1000; /* XXX rounding ? */
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ntv->freq = L_GINT((time_freq / 1000LL) << 16);
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ntv->maxerror = time_maxerror;
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ntv->esterror = time_esterror;
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ntv->status = time_status;
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ntv->constant = time_constant;
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if (time_status & STA_NANO)
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ntv->precision = time_precision;
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else
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ntv->precision = time_precision / 1000;
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ntv->tolerance = MAXFREQ * SCALE_PPM;
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#ifdef PPS_SYNC
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ntv->shift = pps_shift;
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ntv->ppsfreq = L_GINT((pps_freq / 1000LL) << 16);
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if (time_status & STA_NANO)
|
|
ntv->jitter = pps_jitter;
|
|
else
|
|
ntv->jitter = pps_jitter / 1000;
|
|
ntv->stabil = pps_stabil;
|
|
ntv->calcnt = pps_calcnt;
|
|
ntv->errcnt = pps_errcnt;
|
|
ntv->jitcnt = pps_jitcnt;
|
|
ntv->stbcnt = pps_stbcnt;
|
|
#endif /* PPS_SYNC */
|
|
retval = ntp_is_time_error(time_status) ? TIME_ERROR : time_state;
|
|
NTP_UNLOCK();
|
|
|
|
*retvalp = retval;
|
|
return (0);
|
|
}
|
|
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct ntp_adjtime_args {
|
|
struct timex *tp;
|
|
};
|
|
#endif
|
|
|
|
int
|
|
sys_ntp_adjtime(struct thread *td, struct ntp_adjtime_args *uap)
|
|
{
|
|
struct timex ntv;
|
|
int error, retval;
|
|
|
|
error = copyin(uap->tp, &ntv, sizeof(ntv));
|
|
if (error == 0) {
|
|
error = kern_ntp_adjtime(td, &ntv, &retval);
|
|
if (error == 0) {
|
|
error = copyout(&ntv, uap->tp, sizeof(ntv));
|
|
if (error == 0)
|
|
td->td_retval[0] = retval;
|
|
}
|
|
}
|
|
return (error);
|
|
}
|
|
|
|
/*
|
|
* second_overflow() - called after ntp_tick_adjust()
|
|
*
|
|
* This routine is ordinarily called immediately following the above
|
|
* routine ntp_tick_adjust(). While these two routines are normally
|
|
* combined, they are separated here only for the purposes of
|
|
* simulation.
|
|
*/
|
|
void
|
|
ntp_update_second(int64_t *adjustment, time_t *newsec)
|
|
{
|
|
int tickrate;
|
|
l_fp ftemp; /* 32/64-bit temporary */
|
|
|
|
NTP_LOCK();
|
|
|
|
/*
|
|
* On rollover of the second both the nanosecond and microsecond
|
|
* clocks are updated and the state machine cranked as
|
|
* necessary. The phase adjustment to be used for the next
|
|
* second is calculated and the maximum error is increased by
|
|
* the tolerance.
|
|
*/
|
|
time_maxerror += MAXFREQ / 1000;
|
|
|
|
/*
|
|
* Leap second processing. If in leap-insert state at
|
|
* the end of the day, the system clock is set back one
|
|
* second; if in leap-delete state, the system clock is
|
|
* set ahead one second. The nano_time() routine or
|
|
* external clock driver will insure that reported time
|
|
* is always monotonic.
|
|
*/
|
|
switch (time_state) {
|
|
/*
|
|
* No warning.
|
|
*/
|
|
case TIME_OK:
|
|
if (time_status & STA_INS)
|
|
time_state = TIME_INS;
|
|
else if (time_status & STA_DEL)
|
|
time_state = TIME_DEL;
|
|
break;
|
|
|
|
/*
|
|
* Insert second 23:59:60 following second
|
|
* 23:59:59.
|
|
*/
|
|
case TIME_INS:
|
|
if (!(time_status & STA_INS))
|
|
time_state = TIME_OK;
|
|
else if ((*newsec) % 86400 == 0) {
|
|
(*newsec)--;
|
|
time_state = TIME_OOP;
|
|
time_tai++;
|
|
}
|
|
break;
|
|
|
|
/*
|
|
* Delete second 23:59:59.
|
|
*/
|
|
case TIME_DEL:
|
|
if (!(time_status & STA_DEL))
|
|
time_state = TIME_OK;
|
|
else if (((*newsec) + 1) % 86400 == 0) {
|
|
(*newsec)++;
|
|
time_tai--;
|
|
time_state = TIME_WAIT;
|
|
}
|
|
break;
|
|
|
|
/*
|
|
* Insert second in progress.
|
|
*/
|
|
case TIME_OOP:
|
|
time_state = TIME_WAIT;
|
|
break;
|
|
|
|
/*
|
|
* Wait for status bits to clear.
|
|
*/
|
|
case TIME_WAIT:
|
|
if (!(time_status & (STA_INS | STA_DEL)))
|
|
time_state = TIME_OK;
|
|
}
|
|
|
|
/*
|
|
* Compute the total time adjustment for the next second
|
|
* in ns. The offset is reduced by a factor depending on
|
|
* whether the PPS signal is operating. Note that the
|
|
* value is in effect scaled by the clock frequency,
|
|
* since the adjustment is added at each tick interrupt.
|
|
*/
|
|
ftemp = time_offset;
|
|
#ifdef PPS_SYNC
|
|
/* XXX even if PPS signal dies we should finish adjustment ? */
|
|
if (time_status & STA_PPSTIME && time_status &
|
|
STA_PPSSIGNAL)
|
|
L_RSHIFT(ftemp, pps_shift);
|
|
else
|
|
L_RSHIFT(ftemp, SHIFT_PLL + time_constant);
|
|
#else
|
|
L_RSHIFT(ftemp, SHIFT_PLL + time_constant);
|
|
#endif /* PPS_SYNC */
|
|
time_adj = ftemp;
|
|
L_SUB(time_offset, ftemp);
|
|
L_ADD(time_adj, time_freq);
|
|
|
|
/*
|
|
* Apply any correction from adjtime(2). If more than one second
|
|
* off we slew at a rate of 5ms/s (5000 PPM) else 500us/s (500 PPM)
|
|
* until the last second is slewed the final < 500 usecs.
|
|
*/
|
|
if (time_adjtime != 0) {
|
|
if (time_adjtime > 1000000)
|
|
tickrate = 5000;
|
|
else if (time_adjtime < -1000000)
|
|
tickrate = -5000;
|
|
else if (time_adjtime > 500)
|
|
tickrate = 500;
|
|
else if (time_adjtime < -500)
|
|
tickrate = -500;
|
|
else
|
|
tickrate = time_adjtime;
|
|
time_adjtime -= tickrate;
|
|
L_LINT(ftemp, tickrate * 1000);
|
|
L_ADD(time_adj, ftemp);
|
|
}
|
|
*adjustment = time_adj;
|
|
|
|
#ifdef PPS_SYNC
|
|
if (pps_valid > 0)
|
|
pps_valid--;
|
|
else
|
|
time_status &= ~STA_PPSSIGNAL;
|
|
#endif /* PPS_SYNC */
|
|
|
|
NTP_UNLOCK();
|
|
}
|
|
|
|
/*
|
|
* hardupdate() - local clock update
|
|
*
|
|
* This routine is called by ntp_adjtime() to update the local clock
|
|
* phase and frequency. The implementation is of an adaptive-parameter,
|
|
* hybrid phase/frequency-lock loop (PLL/FLL). The routine computes new
|
|
* time and frequency offset estimates for each call. If the kernel PPS
|
|
* discipline code is configured (PPS_SYNC), the PPS signal itself
|
|
* determines the new time offset, instead of the calling argument.
|
|
* Presumably, calls to ntp_adjtime() occur only when the caller
|
|
* believes the local clock is valid within some bound (+-128 ms with
|
|
* NTP). If the caller's time is far different than the PPS time, an
|
|
* argument will ensue, and it's not clear who will lose.
|
|
*
|
|
* For uncompensated quartz crystal oscillators and nominal update
|
|
* intervals less than 256 s, operation should be in phase-lock mode,
|
|
* where the loop is disciplined to phase. For update intervals greater
|
|
* than 1024 s, operation should be in frequency-lock mode, where the
|
|
* loop is disciplined to frequency. Between 256 s and 1024 s, the mode
|
|
* is selected by the STA_MODE status bit.
|
|
*/
|
|
static void
|
|
hardupdate(long offset /* clock offset (ns) */)
|
|
{
|
|
long mtemp;
|
|
l_fp ftemp;
|
|
|
|
NTP_ASSERT_LOCKED();
|
|
|
|
/*
|
|
* Select how the phase is to be controlled and from which
|
|
* source. If the PPS signal is present and enabled to
|
|
* discipline the time, the PPS offset is used; otherwise, the
|
|
* argument offset is used.
|
|
*/
|
|
if (!(time_status & STA_PLL))
|
|
return;
|
|
if (!(time_status & STA_PPSTIME && time_status &
|
|
STA_PPSSIGNAL)) {
|
|
if (offset > MAXPHASE)
|
|
time_monitor = MAXPHASE;
|
|
else if (offset < -MAXPHASE)
|
|
time_monitor = -MAXPHASE;
|
|
else
|
|
time_monitor = offset;
|
|
L_LINT(time_offset, time_monitor);
|
|
}
|
|
|
|
/*
|
|
* Select how the frequency is to be controlled and in which
|
|
* mode (PLL or FLL). If the PPS signal is present and enabled
|
|
* to discipline the frequency, the PPS frequency is used;
|
|
* otherwise, the argument offset is used to compute it.
|
|
*/
|
|
if (time_status & STA_PPSFREQ && time_status & STA_PPSSIGNAL) {
|
|
time_reftime = time_uptime;
|
|
return;
|
|
}
|
|
if (time_status & STA_FREQHOLD || time_reftime == 0)
|
|
time_reftime = time_uptime;
|
|
mtemp = time_uptime - time_reftime;
|
|
L_LINT(ftemp, time_monitor);
|
|
L_RSHIFT(ftemp, (SHIFT_PLL + 2 + time_constant) << 1);
|
|
L_MPY(ftemp, mtemp);
|
|
L_ADD(time_freq, ftemp);
|
|
time_status &= ~STA_MODE;
|
|
if (mtemp >= MINSEC && (time_status & STA_FLL || mtemp >
|
|
MAXSEC)) {
|
|
L_LINT(ftemp, (time_monitor << 4) / mtemp);
|
|
L_RSHIFT(ftemp, SHIFT_FLL + 4);
|
|
L_ADD(time_freq, ftemp);
|
|
time_status |= STA_MODE;
|
|
}
|
|
time_reftime = time_uptime;
|
|
if (L_GINT(time_freq) > MAXFREQ)
|
|
L_LINT(time_freq, MAXFREQ);
|
|
else if (L_GINT(time_freq) < -MAXFREQ)
|
|
L_LINT(time_freq, -MAXFREQ);
|
|
}
|
|
|
|
#ifdef PPS_SYNC
|
|
/*
|
|
* hardpps() - discipline CPU clock oscillator to external PPS signal
|
|
*
|
|
* This routine is called at each PPS interrupt in order to discipline
|
|
* the CPU clock oscillator to the PPS signal. There are two independent
|
|
* first-order feedback loops, one for the phase, the other for the
|
|
* frequency. The phase loop measures and grooms the PPS phase offset
|
|
* and leaves it in a handy spot for the seconds overflow routine. The
|
|
* frequency loop averages successive PPS phase differences and
|
|
* calculates the PPS frequency offset, which is also processed by the
|
|
* seconds overflow routine. The code requires the caller to capture the
|
|
* time and architecture-dependent hardware counter values in
|
|
* nanoseconds at the on-time PPS signal transition.
|
|
*
|
|
* Note that, on some Unix systems this routine runs at an interrupt
|
|
* priority level higher than the timer interrupt routine hardclock().
|
|
* Therefore, the variables used are distinct from the hardclock()
|
|
* variables, except for the actual time and frequency variables, which
|
|
* are determined by this routine and updated atomically.
|
|
*
|
|
* tsp - time at current PPS event
|
|
* delta_nsec - time elapsed between the previous and current PPS event
|
|
*/
|
|
void
|
|
hardpps(struct timespec *tsp, long delta_nsec)
|
|
{
|
|
long u_sec, u_nsec, v_nsec; /* temps */
|
|
l_fp ftemp;
|
|
|
|
NTP_LOCK();
|
|
|
|
/*
|
|
* The signal is first processed by a range gate and frequency
|
|
* discriminator. The range gate rejects noise spikes outside
|
|
* the range +-500 us. The frequency discriminator rejects input
|
|
* signals with apparent frequency outside the range 1 +-500
|
|
* PPM. If two hits occur in the same second, we ignore the
|
|
* later hit; if not and a hit occurs outside the range gate,
|
|
* keep the later hit for later comparison, but do not process
|
|
* it.
|
|
*/
|
|
time_status |= STA_PPSSIGNAL | STA_PPSJITTER;
|
|
time_status &= ~(STA_PPSWANDER | STA_PPSERROR);
|
|
pps_valid = PPS_VALID;
|
|
u_sec = tsp->tv_sec;
|
|
u_nsec = tsp->tv_nsec;
|
|
if (u_nsec >= (NANOSECOND >> 1)) {
|
|
u_nsec -= NANOSECOND;
|
|
u_sec++;
|
|
}
|
|
v_nsec = u_nsec - pps_tf[0].tv_nsec;
|
|
if (u_sec == pps_tf[0].tv_sec && v_nsec < NANOSECOND - MAXFREQ)
|
|
goto out;
|
|
pps_tf[2] = pps_tf[1];
|
|
pps_tf[1] = pps_tf[0];
|
|
pps_tf[0].tv_sec = u_sec;
|
|
pps_tf[0].tv_nsec = u_nsec;
|
|
|
|
/*
|
|
* Update the frequency accumulator using the difference between the
|
|
* current and previous PPS event measured directly by the timecounter.
|
|
*/
|
|
pps_fcount += delta_nsec - NANOSECOND;
|
|
if (v_nsec > MAXFREQ || v_nsec < -MAXFREQ)
|
|
goto out;
|
|
time_status &= ~STA_PPSJITTER;
|
|
|
|
/*
|
|
* A three-stage median filter is used to help denoise the PPS
|
|
* time. The median sample becomes the time offset estimate; the
|
|
* difference between the other two samples becomes the time
|
|
* dispersion (jitter) estimate.
|
|
*/
|
|
if (pps_tf[0].tv_nsec > pps_tf[1].tv_nsec) {
|
|
if (pps_tf[1].tv_nsec > pps_tf[2].tv_nsec) {
|
|
v_nsec = pps_tf[1].tv_nsec; /* 0 1 2 */
|
|
u_nsec = pps_tf[0].tv_nsec - pps_tf[2].tv_nsec;
|
|
} else if (pps_tf[2].tv_nsec > pps_tf[0].tv_nsec) {
|
|
v_nsec = pps_tf[0].tv_nsec; /* 2 0 1 */
|
|
u_nsec = pps_tf[2].tv_nsec - pps_tf[1].tv_nsec;
|
|
} else {
|
|
v_nsec = pps_tf[2].tv_nsec; /* 0 2 1 */
|
|
u_nsec = pps_tf[0].tv_nsec - pps_tf[1].tv_nsec;
|
|
}
|
|
} else {
|
|
if (pps_tf[1].tv_nsec < pps_tf[2].tv_nsec) {
|
|
v_nsec = pps_tf[1].tv_nsec; /* 2 1 0 */
|
|
u_nsec = pps_tf[2].tv_nsec - pps_tf[0].tv_nsec;
|
|
} else if (pps_tf[2].tv_nsec < pps_tf[0].tv_nsec) {
|
|
v_nsec = pps_tf[0].tv_nsec; /* 1 0 2 */
|
|
u_nsec = pps_tf[1].tv_nsec - pps_tf[2].tv_nsec;
|
|
} else {
|
|
v_nsec = pps_tf[2].tv_nsec; /* 1 2 0 */
|
|
u_nsec = pps_tf[1].tv_nsec - pps_tf[0].tv_nsec;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Nominal jitter is due to PPS signal noise and interrupt
|
|
* latency. If it exceeds the popcorn threshold, the sample is
|
|
* discarded. otherwise, if so enabled, the time offset is
|
|
* updated. We can tolerate a modest loss of data here without
|
|
* much degrading time accuracy.
|
|
*
|
|
* The measurements being checked here were made with the system
|
|
* timecounter, so the popcorn threshold is not allowed to fall below
|
|
* the number of nanoseconds in two ticks of the timecounter. For a
|
|
* timecounter running faster than 1 GHz the lower bound is 2ns, just
|
|
* to avoid a nonsensical threshold of zero.
|
|
*/
|
|
if (u_nsec > lmax(pps_jitter << PPS_POPCORN,
|
|
2 * (NANOSECOND / (long)qmin(NANOSECOND, tc_getfrequency())))) {
|
|
time_status |= STA_PPSJITTER;
|
|
pps_jitcnt++;
|
|
} else if (time_status & STA_PPSTIME) {
|
|
time_monitor = -v_nsec;
|
|
L_LINT(time_offset, time_monitor);
|
|
}
|
|
pps_jitter += (u_nsec - pps_jitter) >> PPS_FAVG;
|
|
u_sec = pps_tf[0].tv_sec - pps_lastsec;
|
|
if (u_sec < (1 << pps_shift))
|
|
goto out;
|
|
|
|
/*
|
|
* At the end of the calibration interval the difference between
|
|
* the first and last counter values becomes the scaled
|
|
* frequency. It will later be divided by the length of the
|
|
* interval to determine the frequency update. If the frequency
|
|
* exceeds a sanity threshold, or if the actual calibration
|
|
* interval is not equal to the expected length, the data are
|
|
* discarded. We can tolerate a modest loss of data here without
|
|
* much degrading frequency accuracy.
|
|
*/
|
|
pps_calcnt++;
|
|
v_nsec = -pps_fcount;
|
|
pps_lastsec = pps_tf[0].tv_sec;
|
|
pps_fcount = 0;
|
|
u_nsec = MAXFREQ << pps_shift;
|
|
if (v_nsec > u_nsec || v_nsec < -u_nsec || u_sec != (1 << pps_shift)) {
|
|
time_status |= STA_PPSERROR;
|
|
pps_errcnt++;
|
|
goto out;
|
|
}
|
|
|
|
/*
|
|
* Here the raw frequency offset and wander (stability) is
|
|
* calculated. If the wander is less than the wander threshold
|
|
* for four consecutive averaging intervals, the interval is
|
|
* doubled; if it is greater than the threshold for four
|
|
* consecutive intervals, the interval is halved. The scaled
|
|
* frequency offset is converted to frequency offset. The
|
|
* stability metric is calculated as the average of recent
|
|
* frequency changes, but is used only for performance
|
|
* monitoring.
|
|
*/
|
|
L_LINT(ftemp, v_nsec);
|
|
L_RSHIFT(ftemp, pps_shift);
|
|
L_SUB(ftemp, pps_freq);
|
|
u_nsec = L_GINT(ftemp);
|
|
if (u_nsec > PPS_MAXWANDER) {
|
|
L_LINT(ftemp, PPS_MAXWANDER);
|
|
pps_intcnt--;
|
|
time_status |= STA_PPSWANDER;
|
|
pps_stbcnt++;
|
|
} else if (u_nsec < -PPS_MAXWANDER) {
|
|
L_LINT(ftemp, -PPS_MAXWANDER);
|
|
pps_intcnt--;
|
|
time_status |= STA_PPSWANDER;
|
|
pps_stbcnt++;
|
|
} else {
|
|
pps_intcnt++;
|
|
}
|
|
if (pps_intcnt >= 4) {
|
|
pps_intcnt = 4;
|
|
if (pps_shift < pps_shiftmax) {
|
|
pps_shift++;
|
|
pps_intcnt = 0;
|
|
}
|
|
} else if (pps_intcnt <= -4 || pps_shift > pps_shiftmax) {
|
|
pps_intcnt = -4;
|
|
if (pps_shift > PPS_FAVG) {
|
|
pps_shift--;
|
|
pps_intcnt = 0;
|
|
}
|
|
}
|
|
if (u_nsec < 0)
|
|
u_nsec = -u_nsec;
|
|
pps_stabil += (u_nsec * SCALE_PPM - pps_stabil) >> PPS_FAVG;
|
|
|
|
/*
|
|
* The PPS frequency is recalculated and clamped to the maximum
|
|
* MAXFREQ. If enabled, the system clock frequency is updated as
|
|
* well.
|
|
*/
|
|
L_ADD(pps_freq, ftemp);
|
|
u_nsec = L_GINT(pps_freq);
|
|
if (u_nsec > MAXFREQ)
|
|
L_LINT(pps_freq, MAXFREQ);
|
|
else if (u_nsec < -MAXFREQ)
|
|
L_LINT(pps_freq, -MAXFREQ);
|
|
if (time_status & STA_PPSFREQ)
|
|
time_freq = pps_freq;
|
|
|
|
out:
|
|
NTP_UNLOCK();
|
|
}
|
|
#endif /* PPS_SYNC */
|
|
|
|
#ifndef _SYS_SYSPROTO_H_
|
|
struct adjtime_args {
|
|
struct timeval *delta;
|
|
struct timeval *olddelta;
|
|
};
|
|
#endif
|
|
/* ARGSUSED */
|
|
int
|
|
sys_adjtime(struct thread *td, struct adjtime_args *uap)
|
|
{
|
|
struct timeval delta, olddelta, *deltap;
|
|
int error;
|
|
|
|
if (uap->delta) {
|
|
error = copyin(uap->delta, &delta, sizeof(delta));
|
|
if (error)
|
|
return (error);
|
|
deltap = δ
|
|
} else
|
|
deltap = NULL;
|
|
error = kern_adjtime(td, deltap, &olddelta);
|
|
if (uap->olddelta && error == 0)
|
|
error = copyout(&olddelta, uap->olddelta, sizeof(olddelta));
|
|
return (error);
|
|
}
|
|
|
|
int
|
|
kern_adjtime(struct thread *td, struct timeval *delta, struct timeval *olddelta)
|
|
{
|
|
struct timeval atv;
|
|
int64_t ltr, ltw;
|
|
int error;
|
|
|
|
if (delta != NULL) {
|
|
error = priv_check(td, PRIV_ADJTIME);
|
|
if (error != 0)
|
|
return (error);
|
|
ltw = (int64_t)delta->tv_sec * 1000000 + delta->tv_usec;
|
|
}
|
|
NTP_LOCK();
|
|
ltr = time_adjtime;
|
|
if (delta != NULL)
|
|
time_adjtime = ltw;
|
|
NTP_UNLOCK();
|
|
if (olddelta != NULL) {
|
|
atv.tv_sec = ltr / 1000000;
|
|
atv.tv_usec = ltr % 1000000;
|
|
if (atv.tv_usec < 0) {
|
|
atv.tv_usec += 1000000;
|
|
atv.tv_sec--;
|
|
}
|
|
*olddelta = atv;
|
|
}
|
|
return (0);
|
|
}
|
|
|
|
static struct callout resettodr_callout;
|
|
static int resettodr_period = 1800;
|
|
|
|
static void
|
|
periodic_resettodr(void *arg __unused)
|
|
{
|
|
|
|
/*
|
|
* Read of time_status is lock-less, which is fine since
|
|
* ntp_is_time_error() operates on the consistent read value.
|
|
*/
|
|
if (!ntp_is_time_error(time_status))
|
|
resettodr();
|
|
if (resettodr_period > 0)
|
|
callout_schedule(&resettodr_callout, resettodr_period * hz);
|
|
}
|
|
|
|
static void
|
|
shutdown_resettodr(void *arg __unused, int howto __unused)
|
|
{
|
|
|
|
callout_drain(&resettodr_callout);
|
|
/* Another unlocked read of time_status */
|
|
if (resettodr_period > 0 && !ntp_is_time_error(time_status))
|
|
resettodr();
|
|
}
|
|
|
|
static int
|
|
sysctl_resettodr_period(SYSCTL_HANDLER_ARGS)
|
|
{
|
|
int error;
|
|
|
|
error = sysctl_handle_int(oidp, oidp->oid_arg1, oidp->oid_arg2, req);
|
|
if (error || !req->newptr)
|
|
return (error);
|
|
if (cold)
|
|
goto done;
|
|
if (resettodr_period == 0)
|
|
callout_stop(&resettodr_callout);
|
|
else
|
|
callout_reset(&resettodr_callout, resettodr_period * hz,
|
|
periodic_resettodr, NULL);
|
|
done:
|
|
return (0);
|
|
}
|
|
|
|
SYSCTL_PROC(_machdep, OID_AUTO, rtc_save_period, CTLTYPE_INT | CTLFLAG_RWTUN |
|
|
CTLFLAG_MPSAFE, &resettodr_period, 1800, sysctl_resettodr_period, "I",
|
|
"Save system time to RTC with this period (in seconds)");
|
|
|
|
static void
|
|
start_periodic_resettodr(void *arg __unused)
|
|
{
|
|
|
|
EVENTHANDLER_REGISTER(shutdown_pre_sync, shutdown_resettodr, NULL,
|
|
SHUTDOWN_PRI_FIRST);
|
|
callout_init(&resettodr_callout, 1);
|
|
if (resettodr_period == 0)
|
|
return;
|
|
callout_reset(&resettodr_callout, resettodr_period * hz,
|
|
periodic_resettodr, NULL);
|
|
}
|
|
|
|
SYSINIT(periodic_resettodr, SI_SUB_LAST, SI_ORDER_MIDDLE,
|
|
start_periodic_resettodr, NULL);
|