| 0,0 → 1,1001 |
|---|
| /*- |
| *********************************************************************** |
| * * |
| * Copyright (c) David L. Mills 1993-2001 * |
| * * |
| * 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. * |
| * * |
| **********************************************************************/ |
| |
| /* |
| * Adapted from the original sources for FreeBSD and timecounters by: |
| * Poul-Henning Kamp <phk@FreeBSD.org>. |
| * |
| * The 32bit version of the "LP" macros seems a bit past its "sell by" |
| * date so I have retained only the 64bit version and included it directly |
| * in this file. |
| * |
| * Only minor changes done to interface with the timecounters over in |
| * sys/kern/kern_clock.c. Some of the comments below may be (even more) |
| * confusing and/or plain wrong in that context. |
| */ |
| |
| #include <sys/cdefs.h> |
| __FBSDID("$FreeBSD: src/sys/kern/kern_ntptime.c,v 1.59 2005/05/28 14:34:41 rwatson Exp $"); |
| |
| #include "opt_ntp.h" |
| |
| #include <sys/param.h> |
| #include <sys/systm.h> |
| #include <sys/sysproto.h> |
| #include <sys/jail.h> |
| #include <sys/kernel.h> |
| #include <sys/proc.h> |
| #include <sys/lock.h> |
| #include <sys/mutex.h> |
| #include <sys/time.h> |
| #include <sys/timex.h> |
| #include <sys/timetc.h> |
| #include <sys/timepps.h> |
| #include <sys/syscallsubr.h> |
| #include <sys/sysctl.h> |
| |
| /* |
| * Single-precision macros for 64-bit machines |
| */ |
| typedef int64_t l_fp; |
| #define L_ADD(v, u) ((v) += (u)) |
| #define L_SUB(v, u) ((v) -= (u)) |
| #define L_ADDHI(v, a) ((v) += (int64_t)(a) << 32) |
| #define L_NEG(v) ((v) = -(v)) |
| #define L_RSHIFT(v, n) \ |
| do { \ |
| if ((v) < 0) \ |
| (v) = -(-(v) >> (n)); \ |
| else \ |
| (v) = (v) >> (n); \ |
| } while (0) |
| #define L_MPY(v, a) ((v) *= (a)) |
| #define L_CLR(v) ((v) = 0) |
| #define L_ISNEG(v) ((v) < 0) |
| #define L_LINT(v, a) ((v) = (int64_t)(a) << 32) |
| #define L_GINT(v) ((v) < 0 ? -(-(v) >> 32) : (v) >> 32) |
| |
| /* |
| * Generic NTP kernel interface |
| * |
| * These routines constitute 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 other routines in this module to adjust the |
| * phase and frequency of the clock discipline loop which controls the |
| * system clock. |
| * |
| * When the kernel time is reckoned directly in nanoseconds (NTP_NANO |
| * defined), the time at each tick interrupt is derived directly from |
| * the kernel time variable. When the kernel time is reckoned in |
| * microseconds, (NTP_NANO undefined), the time is derived from the |
| * kernel time variable together with a variable representing the |
| * leftover nanoseconds at the last tick interrupt. In either case, the |
| * current nanosecond time is reckoned from these values plus an |
| * interpolated value derived by the clock routines in another |
| * architecture-specific module. The interpolation can use either a |
| * dedicated counter or a processor cycle counter (PCC) implemented in |
| * some architectures. |
| * |
| * Note that all routines must run at priority splclock or higher. |
| */ |
| /* |
| * Phase/frequency-lock loop (PLL/FLL) definitions |
| * |
| * The nanosecond clock discipline uses two variable types, time |
| * variables and frequency variables. Both types are represented as 64- |
| * bit fixed-point quantities with the decimal point between two 32-bit |
| * halves. On a 32-bit machine, each half is represented as a single |
| * word and mathematical operations are done using multiple-precision |
| * arithmetic. On a 64-bit machine, ordinary computer arithmetic is |
| * used. |
| * |
| * A time variable is a signed 64-bit fixed-point number in ns and |
| * fraction. It represents the remaining time offset to be amortized |
| * over succeeding tick interrupts. The maximum time offset is about |
| * 0.5 s and the resolution is about 2.3e-10 ns. |
| * |
| * 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3 |
| * 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 |
| * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| * |s s s| ns | |
| * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| * | fraction | |
| * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| * |
| * A frequency variable is a signed 64-bit fixed-point number in ns/s |
| * and fraction. It represents the ns and fraction to be added to the |
| * kernel time variable at each second. The maximum frequency offset is |
| * about +-500000 ns/s and the resolution is about 2.3e-10 ns/s. |
| * |
| * 1 1 1 1 1 1 1 1 1 1 2 2 2 2 2 2 2 2 2 2 3 3 |
| * 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 |
| * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| * |s s s s s s s s s s s s s| ns/s | |
| * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| * | fraction | |
| * +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| */ |
| /* |
| * The following variables establish the state of the PLL/FLL and the |
| * residual time and frequency offset of the local clock. |
| */ |
| #define SHIFT_PLL 4 /* PLL loop gain (shift) */ |
| #define SHIFT_FLL 2 /* FLL loop gain (shift) */ |
| |
| static int time_state = TIME_OK; /* clock state */ |
| static int time_status = STA_UNSYNC; /* clock status bits */ |
| static long time_tai; /* TAI offset (s) */ |
| static long time_monitor; /* last time offset scaled (ns) */ |
| static long time_constant; /* poll interval (shift) (s) */ |
| static long time_precision = 1; /* clock precision (ns) */ |
| static long time_maxerror = MAXPHASE / 1000; /* maximum error (us) */ |
| static long time_esterror = MAXPHASE / 1000; /* estimated error (us) */ |
| static long time_reftime; /* time at last adjustment (s) */ |
| static l_fp time_offset; /* time offset (ns) */ |
| static l_fp time_freq; /* frequency offset (ns/s) */ |
| static l_fp time_adj; /* tick adjust (ns/s) */ |
| |
| static int64_t time_adjtime; /* correction from adjtime(2) (usec) */ |
| |
| #ifdef PPS_SYNC |
| /* |
| * The following variables are used when a pulse-per-second (PPS) signal |
| * is available and connected via a modem control lead. They establish |
| * the engineering parameters of the clock discipline loop when |
| * controlled by the PPS signal. |
| */ |
| #define PPS_FAVG 2 /* min freq avg interval (s) (shift) */ |
| #define PPS_FAVGDEF 8 /* default freq avg int (s) (shift) */ |
| #define PPS_FAVGMAX 15 /* max freq avg interval (s) (shift) */ |
| #define PPS_PAVG 4 /* phase avg interval (s) (shift) */ |
| #define PPS_VALID 120 /* PPS signal watchdog max (s) */ |
| #define PPS_MAXWANDER 100000 /* max PPS wander (ns/s) */ |
| #define PPS_POPCORN 2 /* popcorn spike threshold (shift) */ |
| |
| static struct timespec pps_tf[3]; /* phase median filter */ |
| static l_fp pps_freq; /* scaled frequency offset (ns/s) */ |
| static long pps_fcount; /* frequency accumulator */ |
| static long pps_jitter; /* nominal jitter (ns) */ |
| static long pps_stabil; /* nominal stability (scaled ns/s) */ |
| static long pps_lastsec; /* time at last calibration (s) */ |
| static int pps_valid; /* signal watchdog counter */ |
| static int pps_shift = PPS_FAVG; /* interval duration (s) (shift) */ |
| static int pps_shiftmax = PPS_FAVGDEF; /* max interval duration (s) (shift) */ |
| static int pps_intcnt; /* wander counter */ |
| |
| /* |
| * PPS signal quality monitors |
| */ |
| static long pps_calcnt; /* calibration intervals */ |
| static long pps_jitcnt; /* jitter limit exceeded */ |
| static long pps_stbcnt; /* stability limit exceeded */ |
| static long pps_errcnt; /* calibration errors */ |
| #endif /* PPS_SYNC */ |
| /* |
| * End of phase/frequency-lock loop (PLL/FLL) definitions |
| */ |
| |
| static void ntp_init(void); |
| static void hardupdate(long offset); |
| static void ntp_gettime1(struct ntptimeval *ntvp); |
| |
| static int cf_useradjtime; |
| static int cf_jailadjtime; |
| SYSCTL_INT(_kern, OID_AUTO, useradjtime, CTLFLAG_RW, &cf_useradjtime, 0, |
| "Non-root is allowed to adjust system time"); |
| SYSCTL_INT(_kern, OID_AUTO, jailadjtime, CTLFLAG_RW, &cf_jailadjtime, 0, |
| "System time is allowed to be adjusted from jail"); |
| |
| static void |
| ntp_gettime1(struct ntptimeval *ntvp) |
| { |
| struct timespec atv; /* nanosecond time */ |
| |
| GIANT_REQUIRED; |
| |
| nanotime(&atv); |
| ntvp->time.tv_sec = atv.tv_sec; |
| ntvp->time.tv_nsec = atv.tv_nsec; |
| ntvp->maxerror = time_maxerror; |
| ntvp->esterror = time_esterror; |
| ntvp->tai = time_tai; |
| ntvp->time_state = time_state; |
| |
| /* |
| * 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))) |
| ntvp->time_state = TIME_ERROR; |
| } |
| |
| /* |
| * ntp_gettime() - NTP user application interface |
| * |
| * See the timex.h header file for synopsis and API description. Note |
| * that the TAI offset is returned in the ntvtimeval.tai structure |
| * member. |
| */ |
| #ifndef _SYS_SYSPROTO_H_ |
| struct ntp_gettime_args { |
| struct ntptimeval *ntvp; |
| }; |
| #endif |
| /* ARGSUSED */ |
| int |
| ntp_gettime(struct thread *td, struct ntp_gettime_args *uap) |
| { |
| struct ntptimeval ntv; |
| |
| mtx_lock(&Giant); |
| ntp_gettime1(&ntv); |
| mtx_unlock(&Giant); |
| |
| return (copyout(&ntv, uap->ntvp, sizeof(ntv))); |
| } |
| |
| static int |
| ntp_sysctl(SYSCTL_HANDLER_ARGS) |
| { |
| struct ntptimeval ntv; /* temporary structure */ |
| |
| ntp_gettime1(&ntv); |
| |
| return (sysctl_handle_opaque(oidp, &ntv, sizeof(ntv), req)); |
| } |
| |
| SYSCTL_NODE(_kern, OID_AUTO, ntp_pll, CTLFLAG_RW, 0, ""); |
| SYSCTL_PROC(_kern_ntp_pll, OID_AUTO, gettime, CTLTYPE_OPAQUE|CTLFLAG_RD, |
| 0, sizeof(struct ntptimeval) , ntp_sysctl, "S,ntptimeval", ""); |
| |
| #ifdef PPS_SYNC |
| SYSCTL_INT(_kern_ntp_pll, OID_AUTO, pps_shiftmax, CTLFLAG_RW, &pps_shiftmax, 0, ""); |
| SYSCTL_INT(_kern_ntp_pll, OID_AUTO, pps_shift, CTLFLAG_RW, &pps_shift, 0, ""); |
| SYSCTL_INT(_kern_ntp_pll, OID_AUTO, time_monitor, CTLFLAG_RD, &time_monitor, 0, ""); |
| |
| SYSCTL_OPAQUE(_kern_ntp_pll, OID_AUTO, pps_freq, CTLFLAG_RD, &pps_freq, sizeof(pps_freq), "I", ""); |
| SYSCTL_OPAQUE(_kern_ntp_pll, OID_AUTO, time_freq, CTLFLAG_RD, &time_freq, sizeof(time_freq), "I", ""); |
| #endif |
| /* |
| * ntp_adjtime() - NTP daemon application interface |
| * |
| * See the timex.h header file for synopsis and API description. Note |
| * that the timex.constant structure member has a dual purpose to set |
| * the time constant and to set the TAI offset. |
| */ |
| #ifndef _SYS_SYSPROTO_H_ |
| struct ntp_adjtime_args { |
| struct timex *tp; |
| }; |
| #endif |
| |
| /* |
| * MPSAFE |
| */ |
| int |
| ntp_adjtime(struct thread *td, struct ntp_adjtime_args *uap) |
| { |
| struct timex ntv; /* temporary structure */ |
| long freq; /* frequency ns/s) */ |
| int modes; /* mode bits from structure */ |
| int s; /* caller priority */ |
| int error; |
| |
| error = copyin((caddr_t)uap->tp, (caddr_t)&ntv, sizeof(ntv)); |
| if (error) |
| 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. |
| * Note that either the time constant or TAI offset are loaded |
| * from the ntv.constant member, depending on the mode bits. If |
| * the STA_PLL bit in the status word is cleared, the state and |
| * status words are reset to the initial values at boot. |
| */ |
| mtx_lock(&Giant); |
| modes = ntv.modes; |
| if (modes) { /* XXX really check suser sometimes only? */ |
| #ifdef MAC |
| error = mac_check_system_settime(td->td_ucred); |
| if (error) |
| goto done2; |
| #endif |
| if (!cf_jailadjtime && jailed(td->td_ucred)) { |
| error = EPERM; |
| goto done2; |
| } |
| if (!cf_useradjtime && |
| (error = suser_cred(td->td_ucred, SUSER_ALLOWJAIL)) != 0) |
| goto done2; /* jail is already checked at this point */ |
| } |
| s = splclock(); |
| if (modes & MOD_MAXERROR) |
| time_maxerror = ntv.maxerror; |
| if (modes & MOD_ESTERROR) |
| time_esterror = ntv.esterror; |
| if (modes & MOD_STATUS) { |
| if (time_status & STA_PLL && !(ntv.status & STA_PLL)) { |
| time_state = TIME_OK; |
| time_status = STA_UNSYNC; |
| #ifdef PPS_SYNC |
| pps_shift = PPS_FAVG; |
| #endif /* PPS_SYNC */ |
| } |
| time_status &= STA_RONLY; |
| time_status |= ntv.status & ~STA_RONLY; |
| } |
| if (modes & MOD_TIMECONST) { |
| if (ntv.constant < 0) |
| time_constant = 0; |
| else if (ntv.constant > MAXTC) |
| time_constant = MAXTC; |
| else |
| time_constant = ntv.constant; |
| } |
| if (modes & MOD_TAI) { |
| if (ntv.constant > 0) /* XXX zero & negative numbers ? */ |
| time_tai = ntv.constant; |
| } |
| #ifdef PPS_SYNC |
| if (modes & MOD_PPSMAX) { |
| if (ntv.shift < PPS_FAVG) |
| pps_shiftmax = PPS_FAVG; |
| else if (ntv.shift > PPS_FAVGMAX) |
| pps_shiftmax = PPS_FAVGMAX; |
| else |
| pps_shiftmax = ntv.shift; |
| } |
| #endif /* PPS_SYNC */ |
| if (modes & MOD_NANO) |
| time_status |= STA_NANO; |
| if (modes & MOD_MICRO) |
| time_status &= ~STA_NANO; |
| if (modes & MOD_CLKB) |
| time_status |= STA_CLK; |
| if (modes & MOD_CLKA) |
| time_status &= ~STA_CLK; |
| if (modes & MOD_FREQUENCY) { |
| freq = (ntv.freq * 1000LL) >> 16; |
| if (freq > MAXFREQ) |
| L_LINT(time_freq, MAXFREQ); |
| else if (freq < -MAXFREQ) |
| L_LINT(time_freq, -MAXFREQ); |
| else { |
| /* |
| * ntv.freq is [PPM * 2^16] = [us/s * 2^16] |
| * time_freq is [ns/s * 2^32] |
| */ |
| time_freq = ntv.freq * 1000LL * 65536LL; |
| } |
| #ifdef PPS_SYNC |
| pps_freq = time_freq; |
| #endif /* PPS_SYNC */ |
| } |
| if (modes & MOD_OFFSET) { |
| if (time_status & STA_NANO) |
| hardupdate(ntv.offset); |
| else |
| hardupdate(ntv.offset * 1000); |
| } |
| |
| /* |
| * Retrieve all clock variables. Note that the TAI offset is |
| * returned only by ntp_gettime(); |
| */ |
| if (time_status & STA_NANO) |
| ntv.offset = L_GINT(time_offset); |
| else |
| ntv.offset = L_GINT(time_offset) / 1000; /* XXX rounding ? */ |
| ntv.freq = L_GINT((time_freq / 1000LL) << 16); |
| ntv.maxerror = time_maxerror; |
| ntv.esterror = time_esterror; |
| ntv.status = time_status; |
| ntv.constant = time_constant; |
| if (time_status & STA_NANO) |
| ntv.precision = time_precision; |
| else |
| ntv.precision = time_precision / 1000; |
| ntv.tolerance = MAXFREQ * SCALE_PPM; |
| #ifdef PPS_SYNC |
| ntv.shift = pps_shift; |
| ntv.ppsfreq = L_GINT((pps_freq / 1000LL) << 16); |
| 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 */ |
| splx(s); |
| |
| error = copyout((caddr_t)&ntv, (caddr_t)uap->tp, sizeof(ntv)); |
| if (error) |
| goto done2; |
| |
| /* |
| * 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))) { |
| td->td_retval[0] = TIME_ERROR; |
| } else { |
| td->td_retval[0] = time_state; |
| } |
| done2: |
| mtx_unlock(&Giant); |
| 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 */ |
| |
| /* |
| * 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 (500PPM) |
| * 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_init() - initialize variables and structures |
| * |
| * This routine must be called after the kernel variables hz and tick |
| * are set or changed and before the next tick interrupt. In this |
| * particular implementation, these values are assumed set elsewhere in |
| * the kernel. The design allows the clock frequency and tick interval |
| * to be changed while the system is running. So, this routine should |
| * probably be integrated with the code that does that. |
| */ |
| static void |
| ntp_init() |
| { |
| |
| /* |
| * The following variables are initialized only at startup. Only |
| * those structures not cleared by the compiler need to be |
| * initialized, and these only in the simulator. In the actual |
| * kernel, any nonzero values here will quickly evaporate. |
| */ |
| L_CLR(time_offset); |
| L_CLR(time_freq); |
| #ifdef PPS_SYNC |
| pps_tf[0].tv_sec = pps_tf[0].tv_nsec = 0; |
| pps_tf[1].tv_sec = pps_tf[1].tv_nsec = 0; |
| pps_tf[2].tv_sec = pps_tf[2].tv_nsec = 0; |
| pps_fcount = 0; |
| L_CLR(pps_freq); |
| #endif /* PPS_SYNC */ |
| } |
| |
| SYSINIT(ntpclocks, SI_SUB_CLOCKS, SI_ORDER_MIDDLE, ntp_init, NULL) |
| |
| /* |
| * 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(offset) |
| long offset; /* clock offset (ns) */ |
| { |
| long mtemp; |
| l_fp ftemp; |
| |
| /* |
| * 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_second; |
| return; |
| } |
| if (time_status & STA_FREQHOLD || time_reftime == 0) |
| time_reftime = time_second; |
| mtemp = time_second - 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_second; |
| 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. |
| */ |
| void |
| hardpps(tsp, nsec) |
| struct timespec *tsp; /* time at PPS */ |
| long nsec; /* hardware counter at PPS */ |
| { |
| long u_sec, u_nsec, v_nsec; /* temps */ |
| l_fp ftemp; |
| |
| /* |
| * 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) |
| return; |
| 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; |
| |
| /* |
| * Compute the difference between the current and previous |
| * counter values. If the difference exceeds 0.5 s, assume it |
| * has wrapped around, so correct 1.0 s. If the result exceeds |
| * the tick interval, the sample point has crossed a tick |
| * boundary during the last second, so correct the tick. Very |
| * intricate. |
| */ |
| u_nsec = nsec; |
| if (u_nsec > (NANOSECOND >> 1)) |
| u_nsec -= NANOSECOND; |
| else if (u_nsec < -(NANOSECOND >> 1)) |
| u_nsec += NANOSECOND; |
| pps_fcount += u_nsec; |
| if (v_nsec > MAXFREQ || v_nsec < -MAXFREQ) |
| return; |
| 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. |
| */ |
| if (u_nsec > (pps_jitter << PPS_POPCORN)) { |
| 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)) |
| return; |
| |
| /* |
| * 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++; |
| return; |
| } |
| |
| /* |
| * 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; |
| } |
| #endif /* PPS_SYNC */ |
| |
| #ifndef _SYS_SYSPROTO_H_ |
| struct adjtime_args { |
| struct timeval *delta; |
| struct timeval *olddelta; |
| }; |
| #endif |
| /* |
| * MPSAFE |
| */ |
| /* ARGSUSED */ |
| int |
| 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; |
| int error = 0; |
| |
| #ifdef MAC |
| error = mac_check_system_settime(td->td_ucred); |
| if (error) |
| return (error); |
| #endif |
| if (!cf_jailadjtime && jailed(td->td_ucred)) |
| return (EPERM); |
| if (!cf_useradjtime && (error = suser_cred(td->td_ucred, SUSER_ALLOWJAIL)) != 0) |
| return (error); /* jail is already checked */ |
| |
| mtx_lock(&Giant); |
| if (olddelta) { |
| atv.tv_sec = time_adjtime / 1000000; |
| atv.tv_usec = time_adjtime % 1000000; |
| if (atv.tv_usec < 0) { |
| atv.tv_usec += 1000000; |
| atv.tv_sec--; |
| } |
| *olddelta = atv; |
| } |
| if (delta) |
| time_adjtime = (int64_t)delta->tv_sec * 1000000 + |
| delta->tv_usec; |
| mtx_unlock(&Giant); |
| return (error); |
| } |
| |