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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
}
func getProcID() uint64 {
return uint64(lwp_self())
}
//extern-sysinfo _lwp_self
func lwp_self() int32
//go:noescape
//extern-sysinfo _lwp_park
func lwp_park(ts int32, rel int32, abstime *timespec, unpark int32, hint, unparkhint unsafe.Pointer) int32
//go:noescape
//extern-sysinfo _lwp_unpark
func lwp_unpark(lwp int32, hint unsafe.Pointer) int32
//go:noescape
//extern-sysinfo sysctl
func sysctl(*uint32, uint32, *byte, *uintptr, *byte, uintptr) int32
func sysctlInt(mib []uint32) (int32, bool) {
var out int32
nout := unsafe.Sizeof(out)
ret := sysctl(&mib[0], uint32(len(mib)), (*byte)(unsafe.Pointer(&out)), &nout, nil, 0)
if ret < 0 {
return 0, false
}
return out, true
}
func getncpu() int32 {
if n, ok := sysctlInt([]uint32{_CTL_HW, _HW_NCPUONLINE}); ok {
return int32(n)
}
if n, ok := sysctlInt([]uint32{_CTL_HW, _HW_NCPU}); ok {
return int32(n)
}
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.waitsemacount)
if v > 0 {
if atomic.Cas(&_g_.m.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 != 0 && errno() == _ETIMEDOUT {
return -1
}
}
}
//go:nosplit
func semawakeup(mp *m) {
atomic.Xadd(&mp.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.waitsemacount))
if ret != 0 && errno() != _ESRCH {
// semawakeup can be called on signal stack.
systemstack(func() {
print("thrwakeup addr=", &mp.waitsemacount, " sem=", mp.waitsemacount, " errno=", errno(), "\n")
})
}
}
func osinit() {
ncpu = getncpu()
if physPageSize == 0 {
physPageSize = getPageSize()
}
}
func sysargs(argc int32, argv **byte) {
n := argc + 1
// skip over argv, envp to get to auxv
for argv_index(argv, n) != nil {
n++
}
// skip NULL separator
n++
// now argv+n is auxv
auxv := (*[1 << 28]uintptr)(add(unsafe.Pointer(argv), uintptr(n)*sys.PtrSize))
sysauxv(auxv[:])
}
const (
_AT_NULL = 0 // Terminates the vector
_AT_PAGESZ = 6 // Page size in bytes
)
func sysauxv(auxv []uintptr) {
for i := 0; auxv[i] != _AT_NULL; i += 2 {
tag, val := auxv[i], auxv[i+1]
switch tag {
case _AT_PAGESZ:
physPageSize = val
}
}
}
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