blob: 471e93cb71c9217f24bfa63a166bd01048d805d7 [file] [log] [blame]
// Copyright 2020 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/sys"
"unsafe"
)
// libc function wrappers. Must run on system stack.
//go:nosplit
//go:cgo_unsafe_args
func g0_pthread_key_create(k *pthreadkey, destructor uintptr) int32 {
ret := asmcgocall(unsafe.Pointer(funcPC(pthread_key_create_trampoline)), unsafe.Pointer(&k))
KeepAlive(k)
return ret
}
func pthread_key_create_trampoline()
//go:nosplit
//go:cgo_unsafe_args
func g0_pthread_setspecific(k pthreadkey, value uintptr) int32 {
return asmcgocall(unsafe.Pointer(funcPC(pthread_setspecific_trampoline)), unsafe.Pointer(&k))
}
func pthread_setspecific_trampoline()
//go:cgo_import_dynamic libc_pthread_key_create pthread_key_create "/usr/lib/libSystem.B.dylib"
//go:cgo_import_dynamic libc_pthread_setspecific pthread_setspecific "/usr/lib/libSystem.B.dylib"
// tlsinit allocates a thread-local storage slot for g.
//
// It finds the first available slot using pthread_key_create and uses
// it as the offset value for runtime.tlsg.
//
// This runs at startup on g0 stack, but before g is set, so it must
// not split stack (transitively). g is expected to be nil, so things
// (e.g. asmcgocall) will skip saving or reading g.
//
//go:nosplit
func tlsinit(tlsg *uintptr, tlsbase *[_PTHREAD_KEYS_MAX]uintptr) {
var k pthreadkey
err := g0_pthread_key_create(&k, 0)
if err != 0 {
abort()
}
const magic = 0xc476c475c47957
err = g0_pthread_setspecific(k, magic)
if err != 0 {
abort()
}
for i, x := range tlsbase {
if x == magic {
*tlsg = uintptr(i * sys.PtrSize)
g0_pthread_setspecific(k, 0)
return
}
}
abort()
}