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freebsd-skq/sys/kern/kern_tc.c
mjg a3cb428d33 tc: bcopy -> memcpy
2018-05-04 22:48:10 +00:00

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/*-
* SPDX-License-Identifier: Beerware
*
* ----------------------------------------------------------------------------
* "THE BEER-WARE LICENSE" (Revision 42):
* <phk@FreeBSD.ORG> 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.
*/
#include <sys/cdefs.h>
__FBSDID("$FreeBSD$");
#include "opt_ntp.h"
#include "opt_ffclock.h"
#include <sys/param.h>
#include <sys/kernel.h>
#include <sys/limits.h>
#include <sys/lock.h>
#include <sys/mutex.h>
#include <sys/proc.h>
#include <sys/sbuf.h>
#include <sys/sleepqueue.h>
#include <sys/sysctl.h>
#include <sys/syslog.h>
#include <sys/systm.h>
#include <sys/timeffc.h>
#include <sys/timepps.h>
#include <sys/timetc.h>
#include <sys/timex.h>
#include <sys/vdso.h>
/*
* 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 u_int
dummy_get_timecount(struct timecounter *tc)
{
static u_int now;
return (++now);
}
static struct timecounter dummy_timecounter = {
dummy_get_timecount, 0, ~0u, 1000000, "dummy", -1000000
};
struct timehands {
/* These fields must be initialized by the driver. */
struct timecounter *th_counter;
int64_t th_adjustment;
uint64_t th_scale;
u_int 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. */
u_int th_generation;
struct timehands *th_next;
};
static struct timehands th0;
static struct timehands th1 = {
.th_next = &th0
};
static struct timehands th0 = {
.th_counter = &dummy_timecounter,
.th_scale = (uint64_t)-1 / 1000000,
.th_offset = { .sec = 1 },
.th_generation = 1,
.th_next = &th1
};
static struct timehands *volatile timehands = &th0;
struct timecounter *timecounter = &dummy_timecounter;
static struct timecounter *timecounters = &dummy_timecounter;
int tc_min_ticktock_freq = 1;
volatile time_t time_second = 1;
volatile time_t time_uptime = 1;
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,
&timestepwarnings, 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. */
static void tc_windup(struct bintime *new_boottimebin);
static void cpu_tick_calibrate(int);
void dtrace_getnanotime(struct timespec *tsp);
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)
{
u_int 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));
}
/*
* Return the difference between the timehands' counter value now and what
* was when we copied it to the timehands' offset_count.
*/
static __inline u_int
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 <sys/time.h> 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;
u_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
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;
u_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
getnanouptime(struct timespec *tsp)
{
struct timehands *th;
u_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
getmicrouptime(struct timeval *tvp)
{
struct timehands *th;
u_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
getbintime(struct bintime *bt)
{
struct timehands *th;
u_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
getnanotime(struct timespec *tsp)
{
struct timehands *th;
u_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
getmicrotime(struct timeval *tvp)
{
struct timehands *th;
u_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);
}
#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 */
/*
* 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;
u_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);
}
/*
* System clock currently providing time to the system. Modifiable via sysctl
* when the FFCLOCK option is defined.
*/
int sysclock_active = SYSCLOCK_FBCK;
/* Internal NTP status and error estimates. */
extern int time_status;
extern long time_esterror;
/*
* 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;
clock_snap->sysclock_active = sysclock_active;
/* 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);
}
/*
* Initialize a new timecounter and possibly use it.
*/
void
tc_init(struct timecounter *tc)
{
u_int 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;
if (tc->tc_quality < timecounter->tc_quality)
return;
if (tc->tc_quality == timecounter->tc_quality &&
tc->tc_frequency < timecounter->tc_frequency)
return;
(void)tc->tc_get_timecount(tc);
(void)tc->tc_get_timecount(tc);
timecounter = tc;
}
/* 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);
/*
* Step our concept of UTC. This is done by modifying our estimate of
* when we booted.
*/
void
tc_setclock(struct timespec *ts)
{
struct timespec tbef, taft;
struct bintime bt, bt2;
timespec2bintime(ts, &bt);
nanotime(&tbef);
mtx_lock_spin(&tc_setclock_mtx);
cpu_tick_calibrate(1);
binuptime(&bt2);
bintime_sub(&bt, &bt2);
/* XXX fiddle all the little crinkly bits around the fiords... */
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);
}
}
/*
* 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)
{
struct bintime bt;
struct timehands *th, *tho;
uint64_t scale;
u_int 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;
th = tho->th_next;
ogen = th->th_generation;
th->th_generation = 0;
atomic_thread_fence_rel();
memcpy(th, tho, offsetof(struct timehands, th_generation));
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);
/*
* 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);
/*
* 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 __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
th->th_counter = timecounter;
th->th_offset_count = ncount;
tc_min_ticktock_freq = max(1, timecounter->tc_frequency /
(((uint64_t)timecounter->tc_counter_mask + 1) / 3));
#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
timehands = th;
timekeep_push_vdso();
}
/* 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");
/*
* 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 = atomic_load_int(&pps->ppsinfo.assert_sequence);
cseq = atomic_load_int(&pps->ppsinfo.clear_sequence);
while (aseq == atomic_load_int(&pps->ppsinfo.assert_sequence) &&
cseq == atomic_load_int(&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;
u_int 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);
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);
}
/*
* 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.
*/
static int tc_tick;
SYSCTL_INT(_kern_timecounter, OID_AUTO, tick, CTLFLAG_RD, &tc_tick, 0,
"Approximate number of hardclock ticks in a millisecond");
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);
}
}
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);
}
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, <approx. number of hardclock ticks in a millisecond>).
* 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;
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);
}
#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
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