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// Copyright 2011 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 thrsleep
func thrsleep(ident uintptr, clock_id int32, tsp *timespec, lock uintptr, abort *uint32) int32
//go:noescape
//extern thrwakeup
func thrwakeup(ident uintptr, n int32) int32
//go:noescape
//extern sysctl
func sysctl(*uint32, uint32, *byte, *uintptr, *byte, uintptr) int32
// From OpenBSD's <sys/sysctl.h>
const (
_CTL_KERN = 1
_KERN_OSREV = 3
_CTL_HW = 6
_HW_NCPU = 3
_HW_PAGESIZE = 7
_HW_NCPUONLINE = 25
)
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 {
// Try hw.ncpuonline first because hw.ncpu would report a number twice as
// high as the actual CPUs running on OpenBSD 6.4 with hyperthreading
// disabled (hw.smt=0). See https://golang.org/issue/30127
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 {
if ps, ok := sysctlInt([]uint32{_CTL_HW, _HW_PAGESIZE}); ok {
return uintptr(ps)
}
return 0
}
func getOSRev() int {
if osrev, ok := sysctlInt([]uint32{_CTL_KERN, _KERN_OSREV}); ok {
return int(osrev)
}
return 0
}
//go:nosplit
func semacreate(mp *m) {
}
//go:nosplit
func semasleep(ns int64) int32 {
_g_ := getg()
// Compute sleep deadline.
var tsp *timespec
if ns >= 0 {
var ts timespec
ts.setNsec(ns + nanotime())
tsp = &ts
}
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 woken by semawakeup or timeout; or abort if waitsemacount != 0.
//
// From OpenBSD's __thrsleep(2) manual:
// "The abort argument, if not NULL, points to an int that will
// be examined [...] immediately before blocking. If that int
// is non-zero then __thrsleep() will immediately return EINTR
// without blocking."
ret := thrsleep(uintptr(unsafe.Pointer(&_g_.m.mos.waitsemacount)), _CLOCK_MONOTONIC, tsp, 0, &_g_.m.mos.waitsemacount)
if ret == _EWOULDBLOCK {
return -1
}
}
}
//go:nosplit
func semawakeup(mp *m) {
atomic.Xadd(&mp.mos.waitsemacount, 1)
ret := thrwakeup(uintptr(unsafe.Pointer(&mp.mos.waitsemacount)), 1)
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()
physPageSize = getPageSize()
haveMapStack = getOSRev() >= 201805 // OpenBSD 6.3
}
var haveMapStack = false
|
