/*- *********************************************************************** * * * 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 . * * 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 __FBSDID("$FreeBSD$"); #include "opt_ntp.h" #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #ifdef PPS_SYNC FEATURE(pps_sync, "Support usage of external PPS signal by kernel PLL"); #endif /* * 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 */ 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) */ long time_esterror = MAXPHASE / 1000; /* estimated error (us) */ static long time_reftime; /* uptime 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 ntp_is_time_error(void); static int ntp_is_time_error(void) { /* * 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))) return (1); return (0); } 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; if (ntp_is_time_error()) 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 sys_ntp_gettime(struct thread *td, struct ntp_gettime_args *uap) { struct ntptimeval ntv; mtx_lock(&Giant); ntp_gettime1(&ntv); mtx_unlock(&Giant); td->td_retval[0] = ntv.time_state; 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, "Max interval duration (sec) (shift)"); SYSCTL_INT(_kern_ntp_pll, OID_AUTO, pps_shift, CTLFLAG_RW, &pps_shift, 0, "Interval duration (sec) (shift)"); SYSCTL_LONG(_kern_ntp_pll, OID_AUTO, time_monitor, CTLFLAG_RD, &time_monitor, 0, "Last time offset scaled (ns)"); SYSCTL_OPAQUE(_kern_ntp_pll, OID_AUTO, pps_freq, CTLFLAG_RD, &pps_freq, sizeof(pps_freq), "I", "Scaled frequency offset (ns/sec)"); SYSCTL_OPAQUE(_kern_ntp_pll, OID_AUTO, time_freq, CTLFLAG_RD, &time_freq, sizeof(time_freq), "I", "Frequency offset (ns/sec)"); #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 int sys_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) error = priv_check(td, PRIV_NTP_ADJTIME); if (error) goto done2; 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; if (ntp_is_time_error()) 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_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. */ 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. * * 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)) 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 /* 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; int error; 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) { if ((error = priv_check(td, PRIV_ADJTIME))) { mtx_unlock(&Giant); return (error); } time_adjtime = (int64_t)delta->tv_sec * 1000000 + delta->tv_usec; } mtx_unlock(&Giant); return (0); } static struct callout resettodr_callout; static int resettodr_period = 1800; static void periodic_resettodr(void *arg __unused) { if (!ntp_is_time_error()) { mtx_lock(&Giant); resettodr(); mtx_unlock(&Giant); } 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); if (resettodr_period > 0 && !ntp_is_time_error()) { mtx_lock(&Giant); resettodr(); mtx_unlock(&Giant); } } 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 (resettodr_period == 0) callout_stop(&resettodr_callout); else callout_reset(&resettodr_callout, resettodr_period * hz, periodic_resettodr, NULL); return (0); } SYSCTL_PROC(_machdep, OID_AUTO, rtc_save_period, CTLTYPE_INT|CTLFLAG_RW, &resettodr_period, 1800, sysctl_resettodr_period, "I", "Save system time to RTC with this period (in seconds)"); TUNABLE_INT("machdep.rtc_save_period", &resettodr_period); 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);