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// Copyright 2014 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.
package runtime
import (
"runtime/internal/atomic"
"runtime/internal/sys"
"unsafe"
)
type mOS struct {
waitsemacount uint32
}
//go:noescape
//extern lwp_park
func lwp_park(ts int32, rel int32, abstime *timespec, unpark int32, hint, unparkhint unsafe.Pointer) int32
//go:noescape
//extern lwp_unpark
func lwp_unpark(lwp int32, hint unsafe.Pointer) int32
//go:noescape
//extern sysctl
func sysctl(*uint32, uint32, *byte, *uintptr, *byte, uintptr) int32
// From NetBSD's <sys/sysctl.h>
const (
_CTL_HW = 6
_HW_NCPU = 3
_HW_PAGESIZE = 7
)
func getncpu() int32 {
mib := [2]uint32{_CTL_HW, _HW_NCPU}
out := uint32(0)
nout := unsafe.Sizeof(out)
ret := sysctl(&mib[0], 2, (*byte)(unsafe.Pointer(&out)), &nout, nil, 0)
if ret >= 0 {
return int32(out)
}
return 1
}
func getPageSize() uintptr {
mib := [2]uint32{_CTL_HW, _HW_PAGESIZE}
out := uint32(0)
nout := unsafe.Sizeof(out)
ret := sysctl(&mib[0], 2, (*byte)(unsafe.Pointer(&out)), &nout, nil, 0)
if ret >= 0 {
return uintptr(out)
}
return 0
}
//go:nosplit
func semacreate(mp *m) {
}
//go:nosplit
func semasleep(ns int64) int32 {
_g_ := getg()
var deadline int64
if ns >= 0 {
deadline = nanotime() + ns
}
for {
v := atomic.Load(&_g_.m.mos.waitsemacount)
if v > 0 {
if atomic.Cas(&_g_.m.mos.waitsemacount, v, v-1) {
return 0 // semaphore acquired
}
continue
}
// Sleep until unparked by semawakeup or timeout.
var tsp *timespec
var ts timespec
if ns >= 0 {
wait := deadline - nanotime()
if wait <= 0 {
return -1
}
ts.setNsec(wait)
tsp = &ts
}
ret := lwp_park(_CLOCK_MONOTONIC, _TIMER_RELTIME, tsp, 0, unsafe.Pointer(&_g_.m.waitsemacount), nil)
if ret == _ETIMEDOUT {
return -1
}
}
}
//go:nosplit
func semawakeup(mp *m) {
atomic.Xadd(&mp.mos.waitsemacount, 1)
// From NetBSD's _lwp_unpark(2) manual:
// "If the target LWP is not currently waiting, it will return
// immediately upon the next call to _lwp_park()."
ret := lwp_unpark(int32(mp.procid), unsafe.Pointer(&mp.mos.waitsemacount))
if ret != 0 && ret != _ESRCH {
// semawakeup can be called on signal stack.
systemstack(func() {
print("thrwakeup addr=", &mp.mos.waitsemacount, " sem=", mp.mos.waitsemacount, " ret=", ret, "\n")
})
}
}
func osinit() {
ncpu = getncpu()
if physPageSize == 0 {
physPageSize = getPageSize()
}
}
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