/** * @file * * @ingroup RTEMSScoreTimecounter * * @brief This source file contains the definition of * ::_Timecounter, ::_Timecounter_Time_second, and ::_Timecounter_Time_uptime * and the implementation of _Timecounter_Binuptime(), * _Timecounter_Nanouptime(), _Timecounter_Microuptime(), * _Timecounter_Bintime(), _Timecounter_Nanotime(), _Timecounter_Microtime(), * _Timecounter_Getbinuptime(), _Timecounter_Getnanouptime(), * _Timecounter_Getmicrouptime(), _Timecounter_Getbintime(), * _Timecounter_Getnanotime(), _Timecounter_Getmicrotime(), * _Timecounter_Getboottime(), _Timecounter_Getboottimebin(), and * _Timecounter_Install(). */ /*- * ---------------------------------------------------------------------------- * "THE BEER-WARE LICENSE" (Revision 42): * wrote this file. As long as you retain this notice you * can do whatever you want with this stuff. If we meet some day, and you think * this stuff is worth it, you can buy me a beer in return. Poul-Henning Kamp * ---------------------------------------------------------------------------- * * Copyright (c) 2011, 2015, 2016 The FreeBSD Foundation * All rights reserved. * * Portions of this software were developed by Julien Ridoux at the University * of Melbourne under sponsorship from the FreeBSD Foundation. * * Portions of this software were developed by Konstantin Belousov * under sponsorship from the FreeBSD Foundation. */ #ifdef __rtems__ #include #define _KERNEL #define binuptime(_bt) _Timecounter_Binuptime(_bt) #define nanouptime(_tsp) _Timecounter_Nanouptime(_tsp) #define microuptime(_tvp) _Timecounter_Microuptime(_tvp) #define bintime(_bt) _Timecounter_Bintime(_bt) #define nanotime(_tsp) _Timecounter_Nanotime(_tsp) #define microtime(_tvp) _Timecounter_Microtime(_tvp) #define getbinuptime(_bt) _Timecounter_Getbinuptime(_bt) #define getnanouptime(_tsp) _Timecounter_Getnanouptime(_tsp) #define getmicrouptime(_tvp) _Timecounter_Getmicrouptime(_tvp) #define getbintime(_bt) _Timecounter_Getbintime(_bt) #define getnanotime(_tsp) _Timecounter_Getnanotime(_tsp) #define getmicrotime(_tvp) _Timecounter_Getmicrotime(_tvp) #define getboottime(_tvp) _Timecounter_Getboottime(_tvp) #define getboottimebin(_bt) _Timecounter_Getboottimebin(_bt) #define tc_init _Timecounter_Install #define timecounter _Timecounter #define time_second _Timecounter_Time_second #define time_uptime _Timecounter_Time_uptime #include #include #include #include #include #endif /* __rtems__ */ #include __FBSDID("$FreeBSD: head/sys/kern/kern_tc.c 324528 2017-10-11 11:03:11Z kib $"); #include "opt_compat.h" #include "opt_ntp.h" #include "opt_ffclock.h" #include #ifndef __rtems__ #include #include #include #include #include #include #include #include #include #include #endif /* __rtems__ */ #include #include #include #include #ifndef __rtems__ #include #endif /* __rtems__ */ #ifdef __rtems__ #include #include #include ISR_LOCK_DEFINE(, _Timecounter_Lock, "Timecounter") #define _Timecounter_Release(lock_context) \ _ISR_lock_Release_and_ISR_enable(&_Timecounter_Lock, lock_context) #define hz rtems_clock_get_ticks_per_second() #define printf(...) #define bcopy(x, y, z) memcpy(y, x, z); #define log(...) static inline int builtin_fls(int x) { return x ? sizeof(x) * 8 - __builtin_clz(x) : 0; } #define fls(x) builtin_fls(x) /* FIXME: https://devel.rtems.org/ticket/2348 */ #define ntp_update_second(a, b) do { (void) a; (void) b; } while (0) static inline void atomic_thread_fence_acq(void) { _Atomic_Fence(ATOMIC_ORDER_ACQUIRE); } static inline void atomic_thread_fence_rel(void) { _Atomic_Fence(ATOMIC_ORDER_RELEASE); } static inline u_int atomic_load_acq_int(Atomic_Uint *i) { return (_Atomic_Load_uint(i, ATOMIC_ORDER_ACQUIRE)); } static inline void atomic_store_rel_int(Atomic_Uint *i, u_int val) { _Atomic_Store_uint(i, val, ATOMIC_ORDER_RELEASE); } #endif /* __rtems__ */ /* * A large step happens on boot. This constant detects such steps. * It is relatively small so that ntp_update_second gets called enough * in the typical 'missed a couple of seconds' case, but doesn't loop * forever when the time step is large. */ #define LARGE_STEP 200 /* * Implement a dummy timecounter which we can use until we get a real one * in the air. This allows the console and other early stuff to use * time services. */ static uint32_t dummy_get_timecount(struct timecounter *tc) { #ifndef __rtems__ static uint32_t now; return (++now); #else /* __rtems__ */ return 0; #endif /* __rtems__ */ } static struct timecounter dummy_timecounter = { #ifndef __rtems__ dummy_get_timecount, 0, ~0u, 1000000, "dummy", -1000000 #else /* __rtems__ */ dummy_get_timecount, ~(uint32_t)0, 1000000, "dummy", -1000000 #endif /* __rtems__ */ }; struct timehands { /* These fields must be initialized by the driver. */ struct timecounter *th_counter; int64_t th_adjustment; uint64_t th_scale; uint32_t th_offset_count; struct bintime th_offset; struct bintime th_bintime; struct timeval th_microtime; struct timespec th_nanotime; struct bintime th_boottime; /* Fields not to be copied in tc_windup start with th_generation. */ #ifndef __rtems__ u_int th_generation; #else /* __rtems__ */ Atomic_Uint th_generation; #endif /* __rtems__ */ struct timehands *th_next; }; #if defined(RTEMS_SMP) static struct timehands th0; static struct timehands th1 = { .th_next = &th0 }; #endif static struct timehands th0 = { .th_counter = &dummy_timecounter, .th_scale = (uint64_t)-1 / 1000000, .th_offset = { .sec = 1 }, .th_generation = 1, #ifdef __rtems__ .th_bintime = { .sec = TOD_SECONDS_1970_THROUGH_1988 }, .th_microtime = { TOD_SECONDS_1970_THROUGH_1988, 0 }, .th_nanotime = { TOD_SECONDS_1970_THROUGH_1988, 0 }, .th_boottime = { .sec = TOD_SECONDS_1970_THROUGH_1988 - 1 }, #endif /* __rtems__ */ #if defined(RTEMS_SMP) .th_next = &th1 #else .th_next = &th0 #endif }; static struct timehands *volatile timehands = &th0; struct timecounter *timecounter = &dummy_timecounter; #ifndef __rtems__ static struct timecounter *timecounters = &dummy_timecounter; int tc_min_ticktock_freq = 1; #endif /* __rtems__ */ #ifndef __rtems__ volatile time_t time_second = 1; volatile time_t time_uptime = 1; #else /* __rtems__ */ volatile time_t time_second = TOD_SECONDS_1970_THROUGH_1988; volatile int32_t time_uptime = 1; #endif /* __rtems__ */ #ifndef __rtems__ static int sysctl_kern_boottime(SYSCTL_HANDLER_ARGS); SYSCTL_PROC(_kern, KERN_BOOTTIME, boottime, CTLTYPE_STRUCT|CTLFLAG_RD, NULL, 0, sysctl_kern_boottime, "S,timeval", "System boottime"); SYSCTL_NODE(_kern, OID_AUTO, timecounter, CTLFLAG_RW, 0, ""); static SYSCTL_NODE(_kern_timecounter, OID_AUTO, tc, CTLFLAG_RW, 0, ""); static int timestepwarnings; SYSCTL_INT(_kern_timecounter, OID_AUTO, stepwarnings, CTLFLAG_RW, ×tepwarnings, 0, "Log time steps"); struct bintime bt_timethreshold; struct bintime bt_tickthreshold; sbintime_t sbt_timethreshold; sbintime_t sbt_tickthreshold; struct bintime tc_tick_bt; sbintime_t tc_tick_sbt; int tc_precexp; int tc_timepercentage = TC_DEFAULTPERC; static int sysctl_kern_timecounter_adjprecision(SYSCTL_HANDLER_ARGS); SYSCTL_PROC(_kern_timecounter, OID_AUTO, alloweddeviation, CTLTYPE_INT | CTLFLAG_RWTUN | CTLFLAG_MPSAFE, 0, 0, sysctl_kern_timecounter_adjprecision, "I", "Allowed time interval deviation in percents"); volatile int rtc_generation = 1; static int tc_chosen; /* Non-zero if a specific tc was chosen via sysctl. */ #endif /* __rtems__ */ static void tc_windup(struct bintime *new_boottimebin); #ifndef __rtems__ static void cpu_tick_calibrate(int); #else /* __rtems__ */ static void _Timecounter_Windup(struct bintime *new_boottimebin, ISR_lock_Context *lock_context); #endif /* __rtems__ */ void dtrace_getnanotime(struct timespec *tsp); #ifndef __rtems__ static int sysctl_kern_boottime(SYSCTL_HANDLER_ARGS) { struct timeval boottime; getboottime(&boottime); #ifndef __mips__ #ifdef SCTL_MASK32 int tv[2]; if (req->flags & SCTL_MASK32) { tv[0] = boottime.tv_sec; tv[1] = boottime.tv_usec; return (SYSCTL_OUT(req, tv, sizeof(tv))); } #endif #endif return (SYSCTL_OUT(req, &boottime, sizeof(boottime))); } static int sysctl_kern_timecounter_get(SYSCTL_HANDLER_ARGS) { uint32_t ncount; struct timecounter *tc = arg1; ncount = tc->tc_get_timecount(tc); return (sysctl_handle_int(oidp, &ncount, 0, req)); } static int sysctl_kern_timecounter_freq(SYSCTL_HANDLER_ARGS) { uint64_t freq; struct timecounter *tc = arg1; freq = tc->tc_frequency; return (sysctl_handle_64(oidp, &freq, 0, req)); } #endif /* __rtems__ */ /* * Return the difference between the timehands' counter value now and what * was when we copied it to the timehands' offset_count. */ static __inline uint32_t tc_delta(struct timehands *th) { struct timecounter *tc; tc = th->th_counter; return ((tc->tc_get_timecount(tc) - th->th_offset_count) & tc->tc_counter_mask); } /* * Functions for reading the time. We have to loop until we are sure that * the timehands that we operated on was not updated under our feet. See * the comment in for a description of these 12 functions. */ #ifdef FFCLOCK void fbclock_binuptime(struct bintime *bt) { struct timehands *th; unsigned int gen; do { th = timehands; gen = atomic_load_acq_int(&th->th_generation); *bt = th->th_offset; bintime_addx(bt, th->th_scale * tc_delta(th)); atomic_thread_fence_acq(); } while (gen == 0 || gen != th->th_generation); } void fbclock_nanouptime(struct timespec *tsp) { struct bintime bt; fbclock_binuptime(&bt); bintime2timespec(&bt, tsp); } void fbclock_microuptime(struct timeval *tvp) { struct bintime bt; fbclock_binuptime(&bt); bintime2timeval(&bt, tvp); } void fbclock_bintime(struct bintime *bt) { struct timehands *th; unsigned int gen; do { th = timehands; gen = atomic_load_acq_int(&th->th_generation); *bt = th->th_bintime; bintime_addx(bt, th->th_scale * tc_delta(th)); atomic_thread_fence_acq(); } while (gen == 0 || gen != th->th_generation); } void fbclock_nanotime(struct timespec *tsp) { struct bintime bt; fbclock_bintime(&bt); bintime2timespec(&bt, tsp); } void fbclock_microtime(struct timeval *tvp) { struct bintime bt; fbclock_bintime(&bt); bintime2timeval(&bt, tvp); } void fbclock_getbinuptime(struct bintime *bt) { struct timehands *th; unsigned int gen; do { th = timehands; gen = atomic_load_acq_int(&th->th_generation); *bt = th->th_offset; atomic_thread_fence_acq(); } while (gen == 0 || gen != th->th_generation); } void fbclock_getnanouptime(struct timespec *tsp) { struct timehands *th; unsigned int gen; do { th = timehands; gen = atomic_load_acq_int(&th->th_generation); bintime2timespec(&th->th_offset, tsp); atomic_thread_fence_acq(); } while (gen == 0 || gen != th->th_generation); } void fbclock_getmicrouptime(struct timeval *tvp) { struct timehands *th; unsigned int gen; do { th = timehands; gen = atomic_load_acq_int(&th->th_generation); bintime2timeval(&th->th_offset, tvp); atomic_thread_fence_acq(); } while (gen == 0 || gen != th->th_generation); } void fbclock_getbintime(struct bintime *bt) { struct timehands *th; unsigned int gen; do { th = timehands; gen = atomic_load_acq_int(&th->th_generation); *bt = th->th_bintime; atomic_thread_fence_acq(); } while (gen == 0 || gen != th->th_generation); } void fbclock_getnanotime(struct timespec *tsp) { struct timehands *th; unsigned int gen; do { th = timehands; gen = atomic_load_acq_int(&th->th_generation); *tsp = th->th_nanotime; atomic_thread_fence_acq(); } while (gen == 0 || gen != th->th_generation); } void fbclock_getmicrotime(struct timeval *tvp) { struct timehands *th; unsigned int gen; do { th = timehands; gen = atomic_load_acq_int(&th->th_generation); *tvp = th->th_microtime; atomic_thread_fence_acq(); } while (gen == 0 || gen != th->th_generation); } #else /* !FFCLOCK */ void binuptime(struct bintime *bt) { struct timehands *th; uint32_t gen; do { th = timehands; gen = atomic_load_acq_int(&th->th_generation); *bt = th->th_offset; bintime_addx(bt, th->th_scale * tc_delta(th)); atomic_thread_fence_acq(); } while (gen == 0 || gen != th->th_generation); } #ifdef __rtems__ sbintime_t _Timecounter_Sbinuptime(void) { struct timehands *th; uint32_t gen; sbintime_t sbt; do { th = timehands; gen = atomic_load_acq_int(&th->th_generation); sbt = bttosbt(th->th_offset); sbt += (th->th_scale * tc_delta(th)) >> 32; atomic_thread_fence_acq(); } while (gen == 0 || gen != th->th_generation); return (sbt); } #endif /* __rtems__ */ void nanouptime(struct timespec *tsp) { struct bintime bt; binuptime(&bt); bintime2timespec(&bt, tsp); } void microuptime(struct timeval *tvp) { struct bintime bt; binuptime(&bt); bintime2timeval(&bt, tvp); } void bintime(struct bintime *bt) { struct timehands *th; u_int gen; do { th = timehands; gen = atomic_load_acq_int(&th->th_generation); *bt = th->th_bintime; bintime_addx(bt, th->th_scale * tc_delta(th)); atomic_thread_fence_acq(); } while (gen == 0 || gen != th->th_generation); } void nanotime(struct timespec *tsp) { struct bintime bt; bintime(&bt); bintime2timespec(&bt, tsp); } void microtime(struct timeval *tvp) { struct bintime bt; bintime(&bt); bintime2timeval(&bt, tvp); } void getbinuptime(struct bintime *bt) { struct timehands *th; uint32_t gen; do { th = timehands; gen = atomic_load_acq_int(&th->th_generation); *bt = th->th_offset; atomic_thread_fence_acq(); } while (gen == 0 || gen != th->th_generation); } void getnanouptime(struct timespec *tsp) { struct timehands *th; uint32_t gen; do { th = timehands; gen = atomic_load_acq_int(&th->th_generation); bintime2timespec(&th->th_offset, tsp); atomic_thread_fence_acq(); } while (gen == 0 || gen != th->th_generation); } void getmicrouptime(struct timeval *tvp) { struct timehands *th; uint32_t gen; do { th = timehands; gen = atomic_load_acq_int(&th->th_generation); bintime2timeval(&th->th_offset, tvp); atomic_thread_fence_acq(); } while (gen == 0 || gen != th->th_generation); } void getbintime(struct bintime *bt) { struct timehands *th; uint32_t gen; do { th = timehands; gen = atomic_load_acq_int(&th->th_generation); *bt = th->th_bintime; atomic_thread_fence_acq(); } while (gen == 0 || gen != th->th_generation); } void getnanotime(struct timespec *tsp) { struct timehands *th; uint32_t gen; do { th = timehands; gen = atomic_load_acq_int(&th->th_generation); *tsp = th->th_nanotime; atomic_thread_fence_acq(); } while (gen == 0 || gen != th->th_generation); } void getmicrotime(struct timeval *tvp) { struct timehands *th; uint32_t gen; do { th = timehands; gen = atomic_load_acq_int(&th->th_generation); *tvp = th->th_microtime; atomic_thread_fence_acq(); } while (gen == 0 || gen != th->th_generation); } #endif /* FFCLOCK */ void getboottime(struct timeval *boottime) { struct bintime boottimebin; getboottimebin(&boottimebin); bintime2timeval(&boottimebin, boottime); } void getboottimebin(struct bintime *boottimebin) { struct timehands *th; u_int gen; do { th = timehands; gen = atomic_load_acq_int(&th->th_generation); *boottimebin = th->th_boottime; atomic_thread_fence_acq(); } while (gen == 0 || gen != th->th_generation); } #ifdef FFCLOCK /* * Support for feed-forward synchronization algorithms. This is heavily inspired * by the timehands mechanism but kept independent from it. *_windup() functions * have some connection to avoid accessing the timecounter hardware more than * necessary. */ /* Feed-forward clock estimates kept updated by the synchronization daemon. */ struct ffclock_estimate ffclock_estimate; struct bintime ffclock_boottime; /* Feed-forward boot time estimate. */ uint32_t ffclock_status; /* Feed-forward clock status. */ int8_t ffclock_updated; /* New estimates are available. */ struct mtx ffclock_mtx; /* Mutex on ffclock_estimate. */ struct fftimehands { struct ffclock_estimate cest; struct bintime tick_time; struct bintime tick_time_lerp; ffcounter tick_ffcount; uint64_t period_lerp; volatile uint8_t gen; struct fftimehands *next; }; #define NUM_ELEMENTS(x) (sizeof(x) / sizeof(*x)) static struct fftimehands ffth[10]; static struct fftimehands *volatile fftimehands = ffth; static void ffclock_init(void) { struct fftimehands *cur; struct fftimehands *last; memset(ffth, 0, sizeof(ffth)); last = ffth + NUM_ELEMENTS(ffth) - 1; for (cur = ffth; cur < last; cur++) cur->next = cur + 1; last->next = ffth; ffclock_updated = 0; ffclock_status = FFCLOCK_STA_UNSYNC; mtx_init(&ffclock_mtx, "ffclock lock", NULL, MTX_DEF); } /* * Reset the feed-forward clock estimates. Called from inittodr() to get things * kick started and uses the timecounter nominal frequency as a first period * estimate. Note: this function may be called several time just after boot. * Note: this is the only function that sets the value of boot time for the * monotonic (i.e. uptime) version of the feed-forward clock. */ void ffclock_reset_clock(struct timespec *ts) { struct timecounter *tc; struct ffclock_estimate cest; tc = timehands->th_counter; memset(&cest, 0, sizeof(struct ffclock_estimate)); timespec2bintime(ts, &ffclock_boottime); timespec2bintime(ts, &(cest.update_time)); ffclock_read_counter(&cest.update_ffcount); cest.leapsec_next = 0; cest.period = ((1ULL << 63) / tc->tc_frequency) << 1; cest.errb_abs = 0; cest.errb_rate = 0; cest.status = FFCLOCK_STA_UNSYNC; cest.leapsec_total = 0; cest.leapsec = 0; mtx_lock(&ffclock_mtx); bcopy(&cest, &ffclock_estimate, sizeof(struct ffclock_estimate)); ffclock_updated = INT8_MAX; mtx_unlock(&ffclock_mtx); printf("ffclock reset: %s (%llu Hz), time = %ld.%09lu\n", tc->tc_name, (unsigned long long)tc->tc_frequency, (long)ts->tv_sec, (unsigned long)ts->tv_nsec); } /* * Sub-routine to convert a time interval measured in RAW counter units to time * in seconds stored in bintime format. * NOTE: bintime_mul requires u_int, but the value of the ffcounter may be * larger than the max value of u_int (on 32 bit architecture). Loop to consume * extra cycles. */ static void ffclock_convert_delta(ffcounter ffdelta, uint64_t period, struct bintime *bt) { struct bintime bt2; ffcounter delta, delta_max; delta_max = (1ULL << (8 * sizeof(unsigned int))) - 1; bintime_clear(bt); do { if (ffdelta > delta_max) delta = delta_max; else delta = ffdelta; bt2.sec = 0; bt2.frac = period; bintime_mul(&bt2, (unsigned int)delta); bintime_add(bt, &bt2); ffdelta -= delta; } while (ffdelta > 0); } /* * Update the fftimehands. * Push the tick ffcount and time(s) forward based on current clock estimate. * The conversion from ffcounter to bintime relies on the difference clock * principle, whose accuracy relies on computing small time intervals. If a new * clock estimate has been passed by the synchronisation daemon, make it * current, and compute the linear interpolation for monotonic time if needed. */ static void ffclock_windup(unsigned int delta) { struct ffclock_estimate *cest; struct fftimehands *ffth; struct bintime bt, gap_lerp; ffcounter ffdelta; uint64_t frac; unsigned int polling; uint8_t forward_jump, ogen; /* * Pick the next timehand, copy current ffclock estimates and move tick * times and counter forward. */ forward_jump = 0; ffth = fftimehands->next; ogen = ffth->gen; ffth->gen = 0; cest = &ffth->cest; bcopy(&fftimehands->cest, cest, sizeof(struct ffclock_estimate)); ffdelta = (ffcounter)delta; ffth->period_lerp = fftimehands->period_lerp; ffth->tick_time = fftimehands->tick_time; ffclock_convert_delta(ffdelta, cest->period, &bt); bintime_add(&ffth->tick_time, &bt); ffth->tick_time_lerp = fftimehands->tick_time_lerp; ffclock_convert_delta(ffdelta, ffth->period_lerp, &bt); bintime_add(&ffth->tick_time_lerp, &bt); ffth->tick_ffcount = fftimehands->tick_ffcount + ffdelta; /* * Assess the status of the clock, if the last update is too old, it is * likely the synchronisation daemon is dead and the clock is free * running. */ if (ffclock_updated == 0) { ffdelta = ffth->tick_ffcount - cest->update_ffcount; ffclock_convert_delta(ffdelta, cest->period, &bt); if (bt.sec > 2 * FFCLOCK_SKM_SCALE) ffclock_status |= FFCLOCK_STA_UNSYNC; } /* * If available, grab updated clock estimates and make them current. * Recompute time at this tick using the updated estimates. The clock * estimates passed the feed-forward synchronisation daemon may result * in time conversion that is not monotonically increasing (just after * the update). time_lerp is a particular linear interpolation over the * synchronisation algo polling period that ensures monotonicity for the * clock ids requesting it. */ if (ffclock_updated > 0) { bcopy(&ffclock_estimate, cest, sizeof(struct ffclock_estimate)); ffdelta = ffth->tick_ffcount - cest->update_ffcount; ffth->tick_time = cest->update_time; ffclock_convert_delta(ffdelta, cest->period, &bt); bintime_add(&ffth->tick_time, &bt); /* ffclock_reset sets ffclock_updated to INT8_MAX */ if (ffclock_updated == INT8_MAX) ffth->tick_time_lerp = ffth->tick_time; if (bintime_cmp(&ffth->tick_time, &ffth->tick_time_lerp, >)) forward_jump = 1; else forward_jump = 0; bintime_clear(&gap_lerp); if (forward_jump) { gap_lerp = ffth->tick_time; bintime_sub(&gap_lerp, &ffth->tick_time_lerp); } else { gap_lerp = ffth->tick_time_lerp; bintime_sub(&gap_lerp, &ffth->tick_time); } /* * The reset from the RTC clock may be far from accurate, and * reducing the gap between real time and interpolated time * could take a very long time if the interpolated clock insists * on strict monotonicity. The clock is reset under very strict * conditions (kernel time is known to be wrong and * synchronization daemon has been restarted recently. * ffclock_boottime absorbs the jump to ensure boot time is * correct and uptime functions stay consistent. */ if (((ffclock_status & FFCLOCK_STA_UNSYNC) == FFCLOCK_STA_UNSYNC) && ((cest->status & FFCLOCK_STA_UNSYNC) == 0) && ((cest->status & FFCLOCK_STA_WARMUP) == FFCLOCK_STA_WARMUP)) { if (forward_jump) bintime_add(&ffclock_boottime, &gap_lerp); else bintime_sub(&ffclock_boottime, &gap_lerp); ffth->tick_time_lerp = ffth->tick_time; bintime_clear(&gap_lerp); } ffclock_status = cest->status; ffth->period_lerp = cest->period; /* * Compute corrected period used for the linear interpolation of * time. The rate of linear interpolation is capped to 5000PPM * (5ms/s). */ if (bintime_isset(&gap_lerp)) { ffdelta = cest->update_ffcount; ffdelta -= fftimehands->cest.update_ffcount; ffclock_convert_delta(ffdelta, cest->period, &bt); polling = bt.sec; bt.sec = 0; bt.frac = 5000000 * (uint64_t)18446744073LL; bintime_mul(&bt, polling); if (bintime_cmp(&gap_lerp, &bt, >)) gap_lerp = bt; /* Approximate 1 sec by 1-(1/2^64) to ease arithmetic */ frac = 0; if (gap_lerp.sec > 0) { frac -= 1; frac /= ffdelta / gap_lerp.sec; } frac += gap_lerp.frac / ffdelta; if (forward_jump) ffth->period_lerp += frac; else ffth->period_lerp -= frac; } ffclock_updated = 0; } if (++ogen == 0) ogen = 1; ffth->gen = ogen; fftimehands = ffth; } /* * Adjust the fftimehands when the timecounter is changed. Stating the obvious, * the old and new hardware counter cannot be read simultaneously. tc_windup() * does read the two counters 'back to back', but a few cycles are effectively * lost, and not accumulated in tick_ffcount. This is a fairly radical * operation for a feed-forward synchronization daemon, and it is its job to not * pushing irrelevant data to the kernel. Because there is no locking here, * simply force to ignore pending or next update to give daemon a chance to * realize the counter has changed. */ static void ffclock_change_tc(struct timehands *th) { struct fftimehands *ffth; struct ffclock_estimate *cest; struct timecounter *tc; uint8_t ogen; tc = th->th_counter; ffth = fftimehands->next; ogen = ffth->gen; ffth->gen = 0; cest = &ffth->cest; bcopy(&(fftimehands->cest), cest, sizeof(struct ffclock_estimate)); cest->period = ((1ULL << 63) / tc->tc_frequency ) << 1; cest->errb_abs = 0; cest->errb_rate = 0; cest->status |= FFCLOCK_STA_UNSYNC; ffth->tick_ffcount = fftimehands->tick_ffcount; ffth->tick_time_lerp = fftimehands->tick_time_lerp; ffth->tick_time = fftimehands->tick_time; ffth->period_lerp = cest->period; /* Do not lock but ignore next update from synchronization daemon. */ ffclock_updated--; if (++ogen == 0) ogen = 1; ffth->gen = ogen; fftimehands = ffth; } /* * Retrieve feed-forward counter and time of last kernel tick. */ void ffclock_last_tick(ffcounter *ffcount, struct bintime *bt, uint32_t flags) { struct fftimehands *ffth; uint8_t gen; /* * No locking but check generation has not changed. Also need to make * sure ffdelta is positive, i.e. ffcount > tick_ffcount. */ do { ffth = fftimehands; gen = ffth->gen; if ((flags & FFCLOCK_LERP) == FFCLOCK_LERP) *bt = ffth->tick_time_lerp; else *bt = ffth->tick_time; *ffcount = ffth->tick_ffcount; } while (gen == 0 || gen != ffth->gen); } /* * Absolute clock conversion. Low level function to convert ffcounter to * bintime. The ffcounter is converted using the current ffclock period estimate * or the "interpolated period" to ensure monotonicity. * NOTE: this conversion may have been deferred, and the clock updated since the * hardware counter has been read. */ void ffclock_convert_abs(ffcounter ffcount, struct bintime *bt, uint32_t flags) { struct fftimehands *ffth; struct bintime bt2; ffcounter ffdelta; uint8_t gen; /* * No locking but check generation has not changed. Also need to make * sure ffdelta is positive, i.e. ffcount > tick_ffcount. */ do { ffth = fftimehands; gen = ffth->gen; if (ffcount > ffth->tick_ffcount) ffdelta = ffcount - ffth->tick_ffcount; else ffdelta = ffth->tick_ffcount - ffcount; if ((flags & FFCLOCK_LERP) == FFCLOCK_LERP) { *bt = ffth->tick_time_lerp; ffclock_convert_delta(ffdelta, ffth->period_lerp, &bt2); } else { *bt = ffth->tick_time; ffclock_convert_delta(ffdelta, ffth->cest.period, &bt2); } if (ffcount > ffth->tick_ffcount) bintime_add(bt, &bt2); else bintime_sub(bt, &bt2); } while (gen == 0 || gen != ffth->gen); } /* * Difference clock conversion. * Low level function to Convert a time interval measured in RAW counter units * into bintime. The difference clock allows measuring small intervals much more * reliably than the absolute clock. */ void ffclock_convert_diff(ffcounter ffdelta, struct bintime *bt) { struct fftimehands *ffth; uint8_t gen; /* No locking but check generation has not changed. */ do { ffth = fftimehands; gen = ffth->gen; ffclock_convert_delta(ffdelta, ffth->cest.period, bt); } while (gen == 0 || gen != ffth->gen); } /* * Access to current ffcounter value. */ void ffclock_read_counter(ffcounter *ffcount) { struct timehands *th; struct fftimehands *ffth; unsigned int gen, delta; /* * ffclock_windup() called from tc_windup(), safe to rely on * th->th_generation only, for correct delta and ffcounter. */ do { th = timehands; gen = atomic_load_acq_int(&th->th_generation); ffth = fftimehands; delta = tc_delta(th); *ffcount = ffth->tick_ffcount; atomic_thread_fence_acq(); } while (gen == 0 || gen != th->th_generation); *ffcount += delta; } void binuptime(struct bintime *bt) { binuptime_fromclock(bt, sysclock_active); } void nanouptime(struct timespec *tsp) { nanouptime_fromclock(tsp, sysclock_active); } void microuptime(struct timeval *tvp) { microuptime_fromclock(tvp, sysclock_active); } void bintime(struct bintime *bt) { bintime_fromclock(bt, sysclock_active); } void nanotime(struct timespec *tsp) { nanotime_fromclock(tsp, sysclock_active); } void microtime(struct timeval *tvp) { microtime_fromclock(tvp, sysclock_active); } void getbinuptime(struct bintime *bt) { getbinuptime_fromclock(bt, sysclock_active); } void getnanouptime(struct timespec *tsp) { getnanouptime_fromclock(tsp, sysclock_active); } void getmicrouptime(struct timeval *tvp) { getmicrouptime_fromclock(tvp, sysclock_active); } void getbintime(struct bintime *bt) { getbintime_fromclock(bt, sysclock_active); } void getnanotime(struct timespec *tsp) { getnanotime_fromclock(tsp, sysclock_active); } void getmicrotime(struct timeval *tvp) { getmicrouptime_fromclock(tvp, sysclock_active); } #endif /* FFCLOCK */ #ifndef __rtems__ /* * This is a clone of getnanotime and used for walltimestamps. * The dtrace_ prefix prevents fbt from creating probes for * it so walltimestamp can be safely used in all fbt probes. */ void dtrace_getnanotime(struct timespec *tsp) { struct timehands *th; uint32_t gen; do { th = timehands; gen = atomic_load_acq_int(&th->th_generation); *tsp = th->th_nanotime; atomic_thread_fence_acq(); } while (gen == 0 || gen != th->th_generation); } #endif /* __rtems__ */ #ifdef FFCLOCK /* * System clock currently providing time to the system. Modifiable via sysctl * when the FFCLOCK option is defined. */ int sysclock_active = SYSCLOCK_FBCK; #endif /* Internal NTP status and error estimates. */ extern int time_status; extern long time_esterror; #ifndef __rtems__ /* * Take a snapshot of sysclock data which can be used to compare system clocks * and generate timestamps after the fact. */ void sysclock_getsnapshot(struct sysclock_snap *clock_snap, int fast) { struct fbclock_info *fbi; struct timehands *th; struct bintime bt; unsigned int delta, gen; #ifdef FFCLOCK ffcounter ffcount; struct fftimehands *ffth; struct ffclock_info *ffi; struct ffclock_estimate cest; ffi = &clock_snap->ff_info; #endif fbi = &clock_snap->fb_info; delta = 0; do { th = timehands; gen = atomic_load_acq_int(&th->th_generation); fbi->th_scale = th->th_scale; fbi->tick_time = th->th_offset; #ifdef FFCLOCK ffth = fftimehands; ffi->tick_time = ffth->tick_time_lerp; ffi->tick_time_lerp = ffth->tick_time_lerp; ffi->period = ffth->cest.period; ffi->period_lerp = ffth->period_lerp; clock_snap->ffcount = ffth->tick_ffcount; cest = ffth->cest; #endif if (!fast) delta = tc_delta(th); atomic_thread_fence_acq(); } while (gen == 0 || gen != th->th_generation); clock_snap->delta = delta; #ifdef FFCLOCK clock_snap->sysclock_active = sysclock_active; #endif /* Record feedback clock status and error. */ clock_snap->fb_info.status = time_status; /* XXX: Very crude estimate of feedback clock error. */ bt.sec = time_esterror / 1000000; bt.frac = ((time_esterror - bt.sec) * 1000000) * (uint64_t)18446744073709ULL; clock_snap->fb_info.error = bt; #ifdef FFCLOCK if (!fast) clock_snap->ffcount += delta; /* Record feed-forward clock leap second adjustment. */ ffi->leapsec_adjustment = cest.leapsec_total; if (clock_snap->ffcount > cest.leapsec_next) ffi->leapsec_adjustment -= cest.leapsec; /* Record feed-forward clock status and error. */ clock_snap->ff_info.status = cest.status; ffcount = clock_snap->ffcount - cest.update_ffcount; ffclock_convert_delta(ffcount, cest.period, &bt); /* 18446744073709 = int(2^64/1e12), err_bound_rate in [ps/s]. */ bintime_mul(&bt, cest.errb_rate * (uint64_t)18446744073709ULL); /* 18446744073 = int(2^64 / 1e9), since err_abs in [ns]. */ bintime_addx(&bt, cest.errb_abs * (uint64_t)18446744073ULL); clock_snap->ff_info.error = bt; #endif } /* * Convert a sysclock snapshot into a struct bintime based on the specified * clock source and flags. */ int sysclock_snap2bintime(struct sysclock_snap *cs, struct bintime *bt, int whichclock, uint32_t flags) { struct bintime boottimebin; #ifdef FFCLOCK struct bintime bt2; uint64_t period; #endif switch (whichclock) { case SYSCLOCK_FBCK: *bt = cs->fb_info.tick_time; /* If snapshot was created with !fast, delta will be >0. */ if (cs->delta > 0) bintime_addx(bt, cs->fb_info.th_scale * cs->delta); if ((flags & FBCLOCK_UPTIME) == 0) { getboottimebin(&boottimebin); bintime_add(bt, &boottimebin); } break; #ifdef FFCLOCK case SYSCLOCK_FFWD: if (flags & FFCLOCK_LERP) { *bt = cs->ff_info.tick_time_lerp; period = cs->ff_info.period_lerp; } else { *bt = cs->ff_info.tick_time; period = cs->ff_info.period; } /* If snapshot was created with !fast, delta will be >0. */ if (cs->delta > 0) { ffclock_convert_delta(cs->delta, period, &bt2); bintime_add(bt, &bt2); } /* Leap second adjustment. */ if (flags & FFCLOCK_LEAPSEC) bt->sec -= cs->ff_info.leapsec_adjustment; /* Boot time adjustment, for uptime/monotonic clocks. */ if (flags & FFCLOCK_UPTIME) bintime_sub(bt, &ffclock_boottime); break; #endif default: return (EINVAL); break; } return (0); } #endif /* __rtems__ */ /* * Initialize a new timecounter and possibly use it. */ void tc_init(struct timecounter *tc) { #ifndef __rtems__ uint32_t u; struct sysctl_oid *tc_root; u = tc->tc_frequency / tc->tc_counter_mask; /* XXX: We need some margin here, 10% is a guess */ u *= 11; u /= 10; if (u > hz && tc->tc_quality >= 0) { tc->tc_quality = -2000; if (bootverbose) { printf("Timecounter \"%s\" frequency %ju Hz", tc->tc_name, (uintmax_t)tc->tc_frequency); printf(" -- Insufficient hz, needs at least %u\n", u); } } else if (tc->tc_quality >= 0 || bootverbose) { printf("Timecounter \"%s\" frequency %ju Hz quality %d\n", tc->tc_name, (uintmax_t)tc->tc_frequency, tc->tc_quality); } tc->tc_next = timecounters; timecounters = tc; /* * Set up sysctl tree for this counter. */ tc_root = SYSCTL_ADD_NODE_WITH_LABEL(NULL, SYSCTL_STATIC_CHILDREN(_kern_timecounter_tc), OID_AUTO, tc->tc_name, CTLFLAG_RW, 0, "timecounter description", "timecounter"); SYSCTL_ADD_UINT(NULL, SYSCTL_CHILDREN(tc_root), OID_AUTO, "mask", CTLFLAG_RD, &(tc->tc_counter_mask), 0, "mask for implemented bits"); SYSCTL_ADD_PROC(NULL, SYSCTL_CHILDREN(tc_root), OID_AUTO, "counter", CTLTYPE_UINT | CTLFLAG_RD, tc, sizeof(*tc), sysctl_kern_timecounter_get, "IU", "current timecounter value"); SYSCTL_ADD_PROC(NULL, SYSCTL_CHILDREN(tc_root), OID_AUTO, "frequency", CTLTYPE_U64 | CTLFLAG_RD, tc, sizeof(*tc), sysctl_kern_timecounter_freq, "QU", "timecounter frequency"); SYSCTL_ADD_INT(NULL, SYSCTL_CHILDREN(tc_root), OID_AUTO, "quality", CTLFLAG_RD, &(tc->tc_quality), 0, "goodness of time counter"); /* * Do not automatically switch if the current tc was specifically * chosen. Never automatically use a timecounter with negative quality. * Even though we run on the dummy counter, switching here may be * worse since this timecounter may not be monotonic. */ if (tc_chosen) return; if (tc->tc_quality < 0) return; #endif /* __rtems__ */ if (tc->tc_quality < timecounter->tc_quality) return; if (tc->tc_quality == timecounter->tc_quality && tc->tc_frequency < timecounter->tc_frequency) return; #ifndef __rtems__ (void)tc->tc_get_timecount(tc); (void)tc->tc_get_timecount(tc); #endif /* __rtems__ */ timecounter = tc; #ifdef __rtems__ tc_windup(NULL); #endif /* __rtems__ */ } #ifndef __rtems__ /* Report the frequency of the current timecounter. */ uint64_t tc_getfrequency(void) { return (timehands->th_counter->tc_frequency); } static bool sleeping_on_old_rtc(struct thread *td) { /* * td_rtcgen is modified by curthread when it is running, * and by other threads in this function. By finding the thread * on a sleepqueue and holding the lock on the sleepqueue * chain, we guarantee that the thread is not running and that * modifying td_rtcgen is safe. Setting td_rtcgen to zero informs * the thread that it was woken due to a real-time clock adjustment. * (The declaration of td_rtcgen refers to this comment.) */ if (td->td_rtcgen != 0 && td->td_rtcgen != rtc_generation) { td->td_rtcgen = 0; return (true); } return (false); } static struct mtx tc_setclock_mtx; MTX_SYSINIT(tc_setclock_init, &tc_setclock_mtx, "tcsetc", MTX_SPIN); #endif /* __rtems__ */ /* * Step our concept of UTC. This is done by modifying our estimate of * when we booted. */ void #ifndef __rtems__ tc_setclock(struct timespec *ts) #else /* __rtems__ */ _Timecounter_Set_clock(const struct bintime *_bt, ISR_lock_Context *lock_context) #endif /* __rtems__ */ { #ifndef __rtems__ struct timespec tbef, taft; #endif /* __rtems__ */ struct bintime bt, bt2; #ifndef __rtems__ timespec2bintime(ts, &bt); nanotime(&tbef); mtx_lock_spin(&tc_setclock_mtx); cpu_tick_calibrate(1); #else /* __rtems__ */ bt = *_bt; #endif /* __rtems__ */ binuptime(&bt2); bintime_sub(&bt, &bt2); /* XXX fiddle all the little crinkly bits around the fiords... */ #ifndef __rtems__ tc_windup(&bt); mtx_unlock_spin(&tc_setclock_mtx); /* Avoid rtc_generation == 0, since td_rtcgen == 0 is special. */ atomic_add_rel_int(&rtc_generation, 2); sleepq_chains_remove_matching(sleeping_on_old_rtc); if (timestepwarnings) { nanotime(&taft); log(LOG_INFO, "Time stepped from %jd.%09ld to %jd.%09ld (%jd.%09ld)\n", (intmax_t)tbef.tv_sec, tbef.tv_nsec, (intmax_t)taft.tv_sec, taft.tv_nsec, (intmax_t)ts->tv_sec, ts->tv_nsec); } #else /* __rtems__ */ _Timecounter_Windup(&bt, lock_context); #endif /* __rtems__ */ } /* * Initialize the next struct timehands in the ring and make * it the active timehands. Along the way we might switch to a different * timecounter and/or do seconds processing in NTP. Slightly magic. */ static void tc_windup(struct bintime *new_boottimebin) #ifdef __rtems__ { ISR_lock_Context lock_context; _Timecounter_Acquire(&lock_context); _Timecounter_Windup(new_boottimebin, &lock_context); } static void _Timecounter_Windup(struct bintime *new_boottimebin, ISR_lock_Context *lock_context) #endif /* __rtems__ */ { struct bintime bt; struct timehands *th, *tho; uint64_t scale; uint32_t delta, ncount, ogen; int i; time_t t; /* * Make the next timehands a copy of the current one, but do * not overwrite the generation or next pointer. While we * update the contents, the generation must be zero. We need * to ensure that the zero generation is visible before the * data updates become visible, which requires release fence. * For similar reasons, re-reading of the generation after the * data is read should use acquire fence. */ tho = timehands; #if defined(RTEMS_SMP) th = tho->th_next; #else th = tho; #endif ogen = th->th_generation; th->th_generation = 0; atomic_thread_fence_rel(); #if defined(RTEMS_SMP) bcopy(tho, th, offsetof(struct timehands, th_generation)); #endif if (new_boottimebin != NULL) th->th_boottime = *new_boottimebin; /* * Capture a timecounter delta on the current timecounter and if * changing timecounters, a counter value from the new timecounter. * Update the offset fields accordingly. */ delta = tc_delta(th); if (th->th_counter != timecounter) ncount = timecounter->tc_get_timecount(timecounter); else ncount = 0; #ifdef FFCLOCK ffclock_windup(delta); #endif th->th_offset_count += delta; th->th_offset_count &= th->th_counter->tc_counter_mask; while (delta > th->th_counter->tc_frequency) { /* Eat complete unadjusted seconds. */ delta -= th->th_counter->tc_frequency; th->th_offset.sec++; } if ((delta > th->th_counter->tc_frequency / 2) && (th->th_scale * delta < ((uint64_t)1 << 63))) { /* The product th_scale * delta just barely overflows. */ th->th_offset.sec++; } bintime_addx(&th->th_offset, th->th_scale * delta); #ifndef __rtems__ /* * Hardware latching timecounters may not generate interrupts on * PPS events, so instead we poll them. There is a finite risk that * the hardware might capture a count which is later than the one we * got above, and therefore possibly in the next NTP second which might * have a different rate than the current NTP second. It doesn't * matter in practice. */ if (tho->th_counter->tc_poll_pps) tho->th_counter->tc_poll_pps(tho->th_counter); #endif /* __rtems__ */ /* * Deal with NTP second processing. The for loop normally * iterates at most once, but in extreme situations it might * keep NTP sane if timeouts are not run for several seconds. * At boot, the time step can be large when the TOD hardware * has been read, so on really large steps, we call * ntp_update_second only twice. We need to call it twice in * case we missed a leap second. */ bt = th->th_offset; bintime_add(&bt, &th->th_boottime); i = bt.sec - tho->th_microtime.tv_sec; if (i > LARGE_STEP) i = 2; for (; i > 0; i--) { t = bt.sec; ntp_update_second(&th->th_adjustment, &bt.sec); if (bt.sec != t) th->th_boottime.sec += bt.sec - t; } /* Update the UTC timestamps used by the get*() functions. */ th->th_bintime = bt; bintime2timeval(&bt, &th->th_microtime); bintime2timespec(&bt, &th->th_nanotime); /* Now is a good time to change timecounters. */ if (th->th_counter != timecounter) { #ifndef __rtems__ #ifndef __arm__ if ((timecounter->tc_flags & TC_FLAGS_C2STOP) != 0) cpu_disable_c2_sleep++; if ((th->th_counter->tc_flags & TC_FLAGS_C2STOP) != 0) cpu_disable_c2_sleep--; #endif #endif /* __rtems__ */ th->th_counter = timecounter; th->th_offset_count = ncount; #ifndef __rtems__ tc_min_ticktock_freq = max(1, timecounter->tc_frequency / (((uint64_t)timecounter->tc_counter_mask + 1) / 3)); #endif /* __rtems__ */ #ifdef FFCLOCK ffclock_change_tc(th); #endif } /*- * Recalculate the scaling factor. We want the number of 1/2^64 * fractions of a second per period of the hardware counter, taking * into account the th_adjustment factor which the NTP PLL/adjtime(2) * processing provides us with. * * The th_adjustment is nanoseconds per second with 32 bit binary * fraction and we want 64 bit binary fraction of second: * * x = a * 2^32 / 10^9 = a * 4.294967296 * * The range of th_adjustment is +/- 5000PPM so inside a 64bit int * we can only multiply by about 850 without overflowing, that * leaves no suitably precise fractions for multiply before divide. * * Divide before multiply with a fraction of 2199/512 results in a * systematic undercompensation of 10PPM of th_adjustment. On a * 5000PPM adjustment this is a 0.05PPM error. This is acceptable. * * We happily sacrifice the lowest of the 64 bits of our result * to the goddess of code clarity. * */ scale = (uint64_t)1 << 63; scale += (th->th_adjustment / 1024) * 2199; scale /= th->th_counter->tc_frequency; th->th_scale = scale * 2; /* * Now that the struct timehands is again consistent, set the new * generation number, making sure to not make it zero. */ if (++ogen == 0) ogen = 1; atomic_store_rel_int(&th->th_generation, ogen); /* Go live with the new struct timehands. */ #ifdef FFCLOCK switch (sysclock_active) { case SYSCLOCK_FBCK: #endif time_second = th->th_microtime.tv_sec; time_uptime = th->th_offset.sec; #ifdef FFCLOCK break; case SYSCLOCK_FFWD: time_second = fftimehands->tick_time_lerp.sec; time_uptime = fftimehands->tick_time_lerp.sec - ffclock_boottime.sec; break; } #endif #if defined(RTEMS_SMP) timehands = th; #endif #ifndef __rtems__ timekeep_push_vdso(); #endif /* __rtems__ */ #ifdef __rtems__ _Timecounter_Release(lock_context); #endif /* __rtems__ */ } #ifndef __rtems__ /* Report or change the active timecounter hardware. */ static int sysctl_kern_timecounter_hardware(SYSCTL_HANDLER_ARGS) { char newname[32]; struct timecounter *newtc, *tc; int error; tc = timecounter; strlcpy(newname, tc->tc_name, sizeof(newname)); error = sysctl_handle_string(oidp, &newname[0], sizeof(newname), req); if (error != 0 || req->newptr == NULL) return (error); /* Record that the tc in use now was specifically chosen. */ tc_chosen = 1; if (strcmp(newname, tc->tc_name) == 0) return (0); for (newtc = timecounters; newtc != NULL; newtc = newtc->tc_next) { if (strcmp(newname, newtc->tc_name) != 0) continue; /* Warm up new timecounter. */ (void)newtc->tc_get_timecount(newtc); (void)newtc->tc_get_timecount(newtc); timecounter = newtc; /* * The vdso timehands update is deferred until the next * 'tc_windup()'. * * This is prudent given that 'timekeep_push_vdso()' does not * use any locking and that it can be called in hard interrupt * context via 'tc_windup()'. */ return (0); } return (EINVAL); } SYSCTL_PROC(_kern_timecounter, OID_AUTO, hardware, CTLTYPE_STRING | CTLFLAG_RW, 0, 0, sysctl_kern_timecounter_hardware, "A", "Timecounter hardware selected"); /* Report the available timecounter hardware. */ static int sysctl_kern_timecounter_choice(SYSCTL_HANDLER_ARGS) { struct sbuf sb; struct timecounter *tc; int error; sbuf_new_for_sysctl(&sb, NULL, 0, req); for (tc = timecounters; tc != NULL; tc = tc->tc_next) { if (tc != timecounters) sbuf_putc(&sb, ' '); sbuf_printf(&sb, "%s(%d)", tc->tc_name, tc->tc_quality); } error = sbuf_finish(&sb); sbuf_delete(&sb); return (error); } SYSCTL_PROC(_kern_timecounter, OID_AUTO, choice, CTLTYPE_STRING | CTLFLAG_RD, 0, 0, sysctl_kern_timecounter_choice, "A", "Timecounter hardware detected"); #endif /* __rtems__ */ #ifndef __rtems__ /* * RFC 2783 PPS-API implementation. */ /* * Return true if the driver is aware of the abi version extensions in the * pps_state structure, and it supports at least the given abi version number. */ static inline int abi_aware(struct pps_state *pps, int vers) { return ((pps->kcmode & KCMODE_ABIFLAG) && pps->driver_abi >= vers); } static int pps_fetch(struct pps_fetch_args *fapi, struct pps_state *pps) { int err, timo; pps_seq_t aseq, cseq; struct timeval tv; if (fapi->tsformat && fapi->tsformat != PPS_TSFMT_TSPEC) return (EINVAL); /* * If no timeout is requested, immediately return whatever values were * most recently captured. If timeout seconds is -1, that's a request * to block without a timeout. WITNESS won't let us sleep forever * without a lock (we really don't need a lock), so just repeatedly * sleep a long time. */ if (fapi->timeout.tv_sec || fapi->timeout.tv_nsec) { if (fapi->timeout.tv_sec == -1) timo = 0x7fffffff; else { tv.tv_sec = fapi->timeout.tv_sec; tv.tv_usec = fapi->timeout.tv_nsec / 1000; timo = tvtohz(&tv); } aseq = pps->ppsinfo.assert_sequence; cseq = pps->ppsinfo.clear_sequence; while (aseq == pps->ppsinfo.assert_sequence && cseq == pps->ppsinfo.clear_sequence) { if (abi_aware(pps, 1) && pps->driver_mtx != NULL) { if (pps->flags & PPSFLAG_MTX_SPIN) { err = msleep_spin(pps, pps->driver_mtx, "ppsfch", timo); } else { err = msleep(pps, pps->driver_mtx, PCATCH, "ppsfch", timo); } } else { err = tsleep(pps, PCATCH, "ppsfch", timo); } if (err == EWOULDBLOCK) { if (fapi->timeout.tv_sec == -1) { continue; } else { return (ETIMEDOUT); } } else if (err != 0) { return (err); } } } pps->ppsinfo.current_mode = pps->ppsparam.mode; fapi->pps_info_buf = pps->ppsinfo; return (0); } int pps_ioctl(u_long cmd, caddr_t data, struct pps_state *pps) { pps_params_t *app; struct pps_fetch_args *fapi; #ifdef FFCLOCK struct pps_fetch_ffc_args *fapi_ffc; #endif #ifdef PPS_SYNC struct pps_kcbind_args *kapi; #endif KASSERT(pps != NULL, ("NULL pps pointer in pps_ioctl")); switch (cmd) { case PPS_IOC_CREATE: return (0); case PPS_IOC_DESTROY: return (0); case PPS_IOC_SETPARAMS: app = (pps_params_t *)data; if (app->mode & ~pps->ppscap) return (EINVAL); #ifdef FFCLOCK /* Ensure only a single clock is selected for ffc timestamp. */ if ((app->mode & PPS_TSCLK_MASK) == PPS_TSCLK_MASK) return (EINVAL); #endif pps->ppsparam = *app; return (0); case PPS_IOC_GETPARAMS: app = (pps_params_t *)data; *app = pps->ppsparam; app->api_version = PPS_API_VERS_1; return (0); case PPS_IOC_GETCAP: *(int*)data = pps->ppscap; return (0); case PPS_IOC_FETCH: fapi = (struct pps_fetch_args *)data; return (pps_fetch(fapi, pps)); #ifdef FFCLOCK case PPS_IOC_FETCH_FFCOUNTER: fapi_ffc = (struct pps_fetch_ffc_args *)data; if (fapi_ffc->tsformat && fapi_ffc->tsformat != PPS_TSFMT_TSPEC) return (EINVAL); if (fapi_ffc->timeout.tv_sec || fapi_ffc->timeout.tv_nsec) return (EOPNOTSUPP); pps->ppsinfo_ffc.current_mode = pps->ppsparam.mode; fapi_ffc->pps_info_buf_ffc = pps->ppsinfo_ffc; /* Overwrite timestamps if feedback clock selected. */ switch (pps->ppsparam.mode & PPS_TSCLK_MASK) { case PPS_TSCLK_FBCK: fapi_ffc->pps_info_buf_ffc.assert_timestamp = pps->ppsinfo.assert_timestamp; fapi_ffc->pps_info_buf_ffc.clear_timestamp = pps->ppsinfo.clear_timestamp; break; case PPS_TSCLK_FFWD: break; default: break; } return (0); #endif /* FFCLOCK */ case PPS_IOC_KCBIND: #ifdef PPS_SYNC kapi = (struct pps_kcbind_args *)data; /* XXX Only root should be able to do this */ if (kapi->tsformat && kapi->tsformat != PPS_TSFMT_TSPEC) return (EINVAL); if (kapi->kernel_consumer != PPS_KC_HARDPPS) return (EINVAL); if (kapi->edge & ~pps->ppscap) return (EINVAL); pps->kcmode = (kapi->edge & KCMODE_EDGEMASK) | (pps->kcmode & KCMODE_ABIFLAG); return (0); #else return (EOPNOTSUPP); #endif default: return (ENOIOCTL); } } void pps_init(struct pps_state *pps) { pps->ppscap |= PPS_TSFMT_TSPEC | PPS_CANWAIT; if (pps->ppscap & PPS_CAPTUREASSERT) pps->ppscap |= PPS_OFFSETASSERT; if (pps->ppscap & PPS_CAPTURECLEAR) pps->ppscap |= PPS_OFFSETCLEAR; #ifdef FFCLOCK pps->ppscap |= PPS_TSCLK_MASK; #endif pps->kcmode &= ~KCMODE_ABIFLAG; } void pps_init_abi(struct pps_state *pps) { pps_init(pps); if (pps->driver_abi > 0) { pps->kcmode |= KCMODE_ABIFLAG; pps->kernel_abi = PPS_ABI_VERSION; } } void pps_capture(struct pps_state *pps) { struct timehands *th; KASSERT(pps != NULL, ("NULL pps pointer in pps_capture")); th = timehands; pps->capgen = atomic_load_acq_int(&th->th_generation); pps->capth = th; #ifdef FFCLOCK pps->capffth = fftimehands; #endif pps->capcount = th->th_counter->tc_get_timecount(th->th_counter); atomic_thread_fence_acq(); if (pps->capgen != th->th_generation) pps->capgen = 0; } void pps_event(struct pps_state *pps, int event) { struct bintime bt; struct timespec ts, *tsp, *osp; uint32_t tcount, *pcount; int foff; pps_seq_t *pseq; #ifdef FFCLOCK struct timespec *tsp_ffc; pps_seq_t *pseq_ffc; ffcounter *ffcount; #endif #ifdef PPS_SYNC int fhard; #endif KASSERT(pps != NULL, ("NULL pps pointer in pps_event")); /* Nothing to do if not currently set to capture this event type. */ if ((event & pps->ppsparam.mode) == 0) return; /* If the timecounter was wound up underneath us, bail out. */ if (pps->capgen == 0 || pps->capgen != atomic_load_acq_int(&pps->capth->th_generation)) return; /* Things would be easier with arrays. */ if (event == PPS_CAPTUREASSERT) { tsp = &pps->ppsinfo.assert_timestamp; osp = &pps->ppsparam.assert_offset; foff = pps->ppsparam.mode & PPS_OFFSETASSERT; #ifdef PPS_SYNC fhard = pps->kcmode & PPS_CAPTUREASSERT; #endif pcount = &pps->ppscount[0]; pseq = &pps->ppsinfo.assert_sequence; #ifdef FFCLOCK ffcount = &pps->ppsinfo_ffc.assert_ffcount; tsp_ffc = &pps->ppsinfo_ffc.assert_timestamp; pseq_ffc = &pps->ppsinfo_ffc.assert_sequence; #endif } else { tsp = &pps->ppsinfo.clear_timestamp; osp = &pps->ppsparam.clear_offset; foff = pps->ppsparam.mode & PPS_OFFSETCLEAR; #ifdef PPS_SYNC fhard = pps->kcmode & PPS_CAPTURECLEAR; #endif pcount = &pps->ppscount[1]; pseq = &pps->ppsinfo.clear_sequence; #ifdef FFCLOCK ffcount = &pps->ppsinfo_ffc.clear_ffcount; tsp_ffc = &pps->ppsinfo_ffc.clear_timestamp; pseq_ffc = &pps->ppsinfo_ffc.clear_sequence; #endif } /* * If the timecounter changed, we cannot compare the count values, so * we have to drop the rest of the PPS-stuff until the next event. */ if (pps->ppstc != pps->capth->th_counter) { pps->ppstc = pps->capth->th_counter; *pcount = pps->capcount; pps->ppscount[2] = pps->capcount; return; } /* Convert the count to a timespec. */ tcount = pps->capcount - pps->capth->th_offset_count; tcount &= pps->capth->th_counter->tc_counter_mask; bt = pps->capth->th_bintime; bintime_addx(&bt, pps->capth->th_scale * tcount); bintime2timespec(&bt, &ts); /* If the timecounter was wound up underneath us, bail out. */ atomic_thread_fence_acq(); if (pps->capgen != pps->capth->th_generation) return; *pcount = pps->capcount; (*pseq)++; *tsp = ts; if (foff) { timespecadd(tsp, osp, tsp); if (tsp->tv_nsec < 0) { tsp->tv_nsec += 1000000000; tsp->tv_sec -= 1; } } #ifdef FFCLOCK *ffcount = pps->capffth->tick_ffcount + tcount; bt = pps->capffth->tick_time; ffclock_convert_delta(tcount, pps->capffth->cest.period, &bt); bintime_add(&bt, &pps->capffth->tick_time); bintime2timespec(&bt, &ts); (*pseq_ffc)++; *tsp_ffc = ts; #endif #ifdef PPS_SYNC if (fhard) { uint64_t scale; /* * Feed the NTP PLL/FLL. * The FLL wants to know how many (hardware) nanoseconds * elapsed since the previous event. */ tcount = pps->capcount - pps->ppscount[2]; pps->ppscount[2] = pps->capcount; tcount &= pps->capth->th_counter->tc_counter_mask; scale = (uint64_t)1 << 63; scale /= pps->capth->th_counter->tc_frequency; scale *= 2; bt.sec = 0; bt.frac = 0; bintime_addx(&bt, scale * tcount); bintime2timespec(&bt, &ts); hardpps(tsp, ts.tv_nsec + 1000000000 * ts.tv_sec); } #endif /* Wakeup anyone sleeping in pps_fetch(). */ wakeup(pps); } #else /* __rtems__ */ /* FIXME: https://devel.rtems.org/ticket/2349 */ #endif /* __rtems__ */ /* * Timecounters need to be updated every so often to prevent the hardware * counter from overflowing. Updating also recalculates the cached values * used by the get*() family of functions, so their precision depends on * the update frequency. */ #ifndef __rtems__ static int tc_tick; SYSCTL_INT(_kern_timecounter, OID_AUTO, tick, CTLFLAG_RD, &tc_tick, 0, "Approximate number of hardclock ticks in a millisecond"); #endif /* __rtems__ */ #ifndef __rtems__ void tc_ticktock(int cnt) { static int count; if (mtx_trylock_spin(&tc_setclock_mtx)) { count += cnt; if (count >= tc_tick) { count = 0; tc_windup(NULL); } mtx_unlock_spin(&tc_setclock_mtx); } } #else /* __rtems__ */ void _Timecounter_Tick(void) { Per_CPU_Control *cpu_self = _Per_CPU_Get(); if (_Per_CPU_Is_boot_processor(cpu_self)) { tc_windup(NULL); } _Watchdog_Tick(cpu_self); } void _Timecounter_Tick_simple(uint32_t delta, uint32_t offset, ISR_lock_Context *lock_context) { struct bintime bt; struct timehands *th; uint32_t ogen; th = timehands; ogen = th->th_generation; th->th_offset_count = offset; bintime_addx(&th->th_offset, th->th_scale * delta); bt = th->th_offset; bintime_add(&bt, &th->th_boottime); /* Update the UTC timestamps used by the get*() functions. */ th->th_bintime = bt; bintime2timeval(&bt, &th->th_microtime); bintime2timespec(&bt, &th->th_nanotime); /* * Now that the struct timehands is again consistent, set the new * generation number, making sure to not make it zero. */ if (++ogen == 0) ogen = 1; th->th_generation = ogen; /* Go live with the new struct timehands. */ time_second = th->th_microtime.tv_sec; time_uptime = th->th_offset.sec; _Timecounter_Release(lock_context); _Watchdog_Tick(_Per_CPU_Get_snapshot()); } #endif /* __rtems__ */ #ifndef __rtems__ static void __inline tc_adjprecision(void) { int t; if (tc_timepercentage > 0) { t = (99 + tc_timepercentage) / tc_timepercentage; tc_precexp = fls(t + (t >> 1)) - 1; FREQ2BT(hz / tc_tick, &bt_timethreshold); FREQ2BT(hz, &bt_tickthreshold); bintime_shift(&bt_timethreshold, tc_precexp); bintime_shift(&bt_tickthreshold, tc_precexp); } else { tc_precexp = 31; bt_timethreshold.sec = INT_MAX; bt_timethreshold.frac = ~(uint64_t)0; bt_tickthreshold = bt_timethreshold; } sbt_timethreshold = bttosbt(bt_timethreshold); sbt_tickthreshold = bttosbt(bt_tickthreshold); } #endif /* __rtems__ */ #ifndef __rtems__ static int sysctl_kern_timecounter_adjprecision(SYSCTL_HANDLER_ARGS) { int error, val; val = tc_timepercentage; error = sysctl_handle_int(oidp, &val, 0, req); if (error != 0 || req->newptr == NULL) return (error); tc_timepercentage = val; if (cold) goto done; tc_adjprecision(); done: return (0); } static void inittimecounter(void *dummy) { u_int p; int tick_rate; /* * Set the initial timeout to * max(1, ). * People should probably not use the sysctl to set the timeout * to smaller than its initial value, since that value is the * smallest reasonable one. If they want better timestamps they * should use the non-"get"* functions. */ if (hz > 1000) tc_tick = (hz + 500) / 1000; else tc_tick = 1; tc_adjprecision(); FREQ2BT(hz, &tick_bt); tick_sbt = bttosbt(tick_bt); tick_rate = hz / tc_tick; FREQ2BT(tick_rate, &tc_tick_bt); tc_tick_sbt = bttosbt(tc_tick_bt); p = (tc_tick * 1000000) / hz; printf("Timecounters tick every %d.%03u msec\n", p / 1000, p % 1000); #ifdef FFCLOCK ffclock_init(); #endif /* warm up new timecounter (again) and get rolling. */ (void)timecounter->tc_get_timecount(timecounter); (void)timecounter->tc_get_timecount(timecounter); mtx_lock_spin(&tc_setclock_mtx); tc_windup(NULL); mtx_unlock_spin(&tc_setclock_mtx); } SYSINIT(timecounter, SI_SUB_CLOCKS, SI_ORDER_SECOND, inittimecounter, NULL); /* Cpu tick handling -------------------------------------------------*/ static int cpu_tick_variable; static uint64_t cpu_tick_frequency; static DPCPU_DEFINE(uint64_t, tc_cpu_ticks_base); static DPCPU_DEFINE(unsigned, tc_cpu_ticks_last); static uint64_t tc_cpu_ticks(void) { struct timecounter *tc; uint64_t res, *base; unsigned u, *last; critical_enter(); base = DPCPU_PTR(tc_cpu_ticks_base); last = DPCPU_PTR(tc_cpu_ticks_last); tc = timehands->th_counter; u = tc->tc_get_timecount(tc) & tc->tc_counter_mask; if (u < *last) *base += (uint64_t)tc->tc_counter_mask + 1; *last = u; res = u + *base; critical_exit(); return (res); } void cpu_tick_calibration(void) { static time_t last_calib; if (time_uptime != last_calib && !(time_uptime & 0xf)) { cpu_tick_calibrate(0); last_calib = time_uptime; } } /* * This function gets called every 16 seconds on only one designated * CPU in the system from hardclock() via cpu_tick_calibration()(). * * Whenever the real time clock is stepped we get called with reset=1 * to make sure we handle suspend/resume and similar events correctly. */ static void cpu_tick_calibrate(int reset) { static uint64_t c_last; uint64_t c_this, c_delta; static struct bintime t_last; struct bintime t_this, t_delta; uint32_t divi; if (reset) { /* The clock was stepped, abort & reset */ t_last.sec = 0; return; } /* we don't calibrate fixed rate cputicks */ if (!cpu_tick_variable) return; getbinuptime(&t_this); c_this = cpu_ticks(); if (t_last.sec != 0) { c_delta = c_this - c_last; t_delta = t_this; bintime_sub(&t_delta, &t_last); /* * Headroom: * 2^(64-20) / 16[s] = * 2^(44) / 16[s] = * 17.592.186.044.416 / 16 = * 1.099.511.627.776 [Hz] */ divi = t_delta.sec << 20; divi |= t_delta.frac >> (64 - 20); c_delta <<= 20; c_delta /= divi; if (c_delta > cpu_tick_frequency) { if (0 && bootverbose) printf("cpu_tick increased to %ju Hz\n", c_delta); cpu_tick_frequency = c_delta; } } c_last = c_this; t_last = t_this; } void set_cputicker(cpu_tick_f *func, uint64_t freq, unsigned var) { if (func == NULL) { cpu_ticks = tc_cpu_ticks; } else { cpu_tick_frequency = freq; cpu_tick_variable = var; cpu_ticks = func; } } uint64_t cpu_tickrate(void) { if (cpu_ticks == tc_cpu_ticks) return (tc_getfrequency()); return (cpu_tick_frequency); } /* * We need to be slightly careful converting cputicks to microseconds. * There is plenty of margin in 64 bits of microseconds (half a million * years) and in 64 bits at 4 GHz (146 years), but if we do a multiply * before divide conversion (to retain precision) we find that the * margin shrinks to 1.5 hours (one millionth of 146y). * With a three prong approach we never lose significant bits, no * matter what the cputick rate and length of timeinterval is. */ uint64_t cputick2usec(uint64_t tick) { if (tick > 18446744073709551LL) /* floor(2^64 / 1000) */ return (tick / (cpu_tickrate() / 1000000LL)); else if (tick > 18446744073709LL) /* floor(2^64 / 1000000) */ return ((tick * 1000LL) / (cpu_tickrate() / 1000LL)); else return ((tick * 1000000LL) / cpu_tickrate()); } cpu_tick_f *cpu_ticks = tc_cpu_ticks; #endif /* __rtems__ */ #ifndef __rtems__ static int vdso_th_enable = 1; static int sysctl_fast_gettime(SYSCTL_HANDLER_ARGS) { int old_vdso_th_enable, error; old_vdso_th_enable = vdso_th_enable; error = sysctl_handle_int(oidp, &old_vdso_th_enable, 0, req); if (error != 0) return (error); vdso_th_enable = old_vdso_th_enable; return (0); } SYSCTL_PROC(_kern_timecounter, OID_AUTO, fast_gettime, CTLTYPE_INT | CTLFLAG_RW | CTLFLAG_MPSAFE, NULL, 0, sysctl_fast_gettime, "I", "Enable fast time of day"); uint32_t tc_fill_vdso_timehands(struct vdso_timehands *vdso_th) { struct timehands *th; uint32_t enabled; th = timehands; vdso_th->th_scale = th->th_scale; vdso_th->th_offset_count = th->th_offset_count; vdso_th->th_counter_mask = th->th_counter->tc_counter_mask; vdso_th->th_offset = th->th_offset; vdso_th->th_boottime = th->th_boottime; if (th->th_counter->tc_fill_vdso_timehands != NULL) { enabled = th->th_counter->tc_fill_vdso_timehands(vdso_th, th->th_counter); } else enabled = 0; if (!vdso_th_enable) enabled = 0; return (enabled); } #endif /* __rtems__ */ #ifdef COMPAT_FREEBSD32 uint32_t tc_fill_vdso_timehands32(struct vdso_timehands32 *vdso_th32) { struct timehands *th; uint32_t enabled; th = timehands; *(uint64_t *)&vdso_th32->th_scale[0] = th->th_scale; vdso_th32->th_offset_count = th->th_offset_count; vdso_th32->th_counter_mask = th->th_counter->tc_counter_mask; vdso_th32->th_offset.sec = th->th_offset.sec; *(uint64_t *)&vdso_th32->th_offset.frac[0] = th->th_offset.frac; vdso_th32->th_boottime.sec = th->th_boottime.sec; *(uint64_t *)&vdso_th32->th_boottime.frac[0] = th->th_boottime.frac; if (th->th_counter->tc_fill_vdso_timehands32 != NULL) { enabled = th->th_counter->tc_fill_vdso_timehands32(vdso_th32, th->th_counter); } else enabled = 0; if (!vdso_th_enable) enabled = 0; return (enabled); } #endif