blob: dfcd60284d9d2f4357f1b1c24fea617bf102c6e9 [file] [log] [blame]
// Copyright 2017 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 "unsafe"
type mOS struct {
waitsema uintptr // semaphore for parking on locks
}
//extern malloc
func libc_malloc(uintptr) unsafe.Pointer
//go:noescape
//extern sem_init
func sem_init(sem *semt, pshared int32, value uint32) int32
//go:noescape
//extern sem_wait
func sem_wait(sem *semt) int32
//go:noescape
//extern sem_post
func sem_post(sem *semt) int32
//go:noescape
//extern sem_timedwait
func sem_timedwait(sem *semt, timeout *timespec) int32
//go:noescape
//extern clock_gettime
func clock_gettime(clock_id int64, timeout *timespec) int32
//go:nosplit
func semacreate(mp *m) {
if mp.mos.waitsema != 0 {
return
}
var sem *semt
// Call libc's malloc rather than malloc. This will
// allocate space on the C heap. We can't call malloc
// here because it could cause a deadlock.
sem = (*semt)(libc_malloc(unsafe.Sizeof(*sem)))
if sem_init(sem, 0, 0) != 0 {
throw("sem_init")
}
mp.mos.waitsema = uintptr(unsafe.Pointer(sem))
}
//go:nosplit
func semasleep(ns int64) int32 {
_m_ := getg().m
if ns >= 0 {
const CLOCK_REALTIME int64 = 9
var ts timespec
if clock_gettime(CLOCK_REALTIME, &ts) != 0 {
throw("clock_gettime")
}
ts.tv_sec += timespec_sec_t(ns / 1000000000)
ts.tv_nsec += timespec_nsec_t((int64(ts.tv_nsec) + ns) % 1000000000)
if ts.tv_nsec >= 1000000000 {
ts.tv_sec += timespec_sec_t(1)
ts.tv_nsec -= timespec_nsec_t(1000000000)
}
if sem_timedwait((*semt)(unsafe.Pointer(_m_.mos.waitsema)), &ts) != 0 {
err := errno()
if err == _ETIMEDOUT || err == _EAGAIN || err == _EINTR {
return -1
}
throw("sem_timedwait")
}
return 0
}
for {
r1 := sem_wait((*semt)(unsafe.Pointer(_m_.mos.waitsema)))
if r1 == 0 {
break
}
if errno() == _EINTR {
continue
}
throw("sem_wait")
}
return 0
}
//go:nosplit
func semawakeup(mp *m) {
if sem_post((*semt)(unsafe.Pointer(mp.mos.waitsema))) != 0 {
throw("sem_post")
}
}