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// Copyright 2018 The Go Authors. All rights reserved.
// Use of this source code is governed by a BSD-style
// license that can be found in the LICENSE file.
// +build freebsd
package runtime
import (
"runtime/internal/atomic"
"unsafe"
)
const _VDSO_TH_NUM = 4 // defined in <sys/vdso.h> #ifdef _KERNEL
var timekeepSharedPage *vdsoTimekeep
//go:nosplit
func (bt *bintime) Add(bt2 *bintime) {
u := bt.frac
bt.frac += bt2.frac
if u > bt.frac {
bt.sec++
}
bt.sec += bt2.sec
}
//go:nosplit
func (bt *bintime) AddX(x uint64) {
u := bt.frac
bt.frac += x
if u > bt.frac {
bt.sec++
}
}
var (
// binuptimeDummy is used in binuptime as the address of an atomic.Load, to simulate
// an atomic_thread_fence_acq() call which behaves as an instruction reordering and
// memory barrier.
binuptimeDummy uint32
zeroBintime bintime
)
// based on /usr/src/lib/libc/sys/__vdso_gettimeofday.c
//
//go:nosplit
func binuptime(abs bool) (bt bintime) {
timehands := (*[_VDSO_TH_NUM]vdsoTimehands)(add(unsafe.Pointer(timekeepSharedPage), vdsoTimekeepSize))
for {
if timekeepSharedPage.enabled == 0 {
return zeroBintime
}
curr := atomic.Load(&timekeepSharedPage.current) // atomic_load_acq_32
th := &timehands[curr]
gen := atomic.Load(&th.gen) // atomic_load_acq_32
bt = th.offset
if tc, ok := th.getTimecounter(); !ok {
return zeroBintime
} else {
delta := (tc - th.offset_count) & th.counter_mask
bt.AddX(th.scale * uint64(delta))
}
if abs {
bt.Add(&th.boottime)
}
atomic.Load(&binuptimeDummy) // atomic_thread_fence_acq()
if curr == timekeepSharedPage.current && gen != 0 && gen == th.gen {
break
}
}
return bt
}
//go:nosplit
func vdsoClockGettime(clockID int32) bintime {
if timekeepSharedPage == nil || timekeepSharedPage.ver != _VDSO_TK_VER_CURR {
return zeroBintime
}
abs := false
switch clockID {
case _CLOCK_MONOTONIC:
/* ok */
case _CLOCK_REALTIME:
abs = true
default:
return zeroBintime
}
return binuptime(abs)
}
func fallback_nanotime() int64
func fallback_walltime() (sec int64, nsec int32)
//go:nosplit
func nanotime1() int64 {
bt := vdsoClockGettime(_CLOCK_MONOTONIC)
if bt == zeroBintime {
return fallback_nanotime()
}
return int64((1e9 * uint64(bt.sec)) + ((1e9 * uint64(bt.frac>>32)) >> 32))
}
func walltime1() (sec int64, nsec int32) {
bt := vdsoClockGettime(_CLOCK_REALTIME)
if bt == zeroBintime {
return fallback_walltime()
}
return int64(bt.sec), int32((1e9 * uint64(bt.frac>>32)) >> 32)
}
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