mirror of https://go.googlesource.com/go
66 lines
1.7 KiB
Go
66 lines
1.7 KiB
Go
// Copyright 2020 The Go Authors. All rights reserved.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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package runtime
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import (
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"internal/abi"
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"internal/goarch"
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"unsafe"
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)
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// libc function wrappers. Must run on system stack.
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//go:nosplit
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//go:cgo_unsafe_args
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func g0_pthread_key_create(k *pthreadkey, destructor uintptr) int32 {
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ret := asmcgocall(unsafe.Pointer(abi.FuncPCABI0(pthread_key_create_trampoline)), unsafe.Pointer(&k))
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KeepAlive(k)
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return ret
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}
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func pthread_key_create_trampoline()
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//go:nosplit
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//go:cgo_unsafe_args
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func g0_pthread_setspecific(k pthreadkey, value uintptr) int32 {
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return asmcgocall(unsafe.Pointer(abi.FuncPCABI0(pthread_setspecific_trampoline)), unsafe.Pointer(&k))
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}
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func pthread_setspecific_trampoline()
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//go:cgo_import_dynamic libc_pthread_key_create pthread_key_create "/usr/lib/libSystem.B.dylib"
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//go:cgo_import_dynamic libc_pthread_setspecific pthread_setspecific "/usr/lib/libSystem.B.dylib"
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// tlsinit allocates a thread-local storage slot for g.
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//
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// It finds the first available slot using pthread_key_create and uses
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// it as the offset value for runtime.tlsg.
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//
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// This runs at startup on g0 stack, but before g is set, so it must
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// not split stack (transitively). g is expected to be nil, so things
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// (e.g. asmcgocall) will skip saving or reading g.
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//
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//go:nosplit
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func tlsinit(tlsg *uintptr, tlsbase *[_PTHREAD_KEYS_MAX]uintptr) {
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var k pthreadkey
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err := g0_pthread_key_create(&k, 0)
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if err != 0 {
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abort()
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}
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const magic = 0xc476c475c47957
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err = g0_pthread_setspecific(k, magic)
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if err != 0 {
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abort()
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}
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for i, x := range tlsbase {
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if x == magic {
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*tlsg = uintptr(i * goarch.PtrSize)
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g0_pthread_setspecific(k, 0)
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return
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}
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}
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abort()
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}
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