go_linux_arm64.go Raw History Folder

1// Copyright 2011 The Go Authors. All rights reserved.
2// Use of this source code is governed by a BSD-style
3// license that can be found in the LICENSE file.
4
5//go:build !cgo
6
7package fakecgo
8
9import "unsafe"
10
11//go:nosplit
12func _cgo_sys_thread_start(ts *ThreadStart) {
13	var attr pthread_attr_t
14	var ign, oset sigset_t
15	var p pthread_t
16	var size size_t
17	var err int
18
19	//fprintf(stderr, "runtime/cgo: _cgo_sys_thread_start: fn=%p, g=%p\n", ts->fn, ts->g); // debug
20	sigfillset(&ign)
21	pthread_sigmask(SIG_SETMASK, &ign, &oset)
22
23	pthread_attr_init(&attr)
24	pthread_attr_getstacksize(&attr, &size)
25	// Leave stacklo=0 and set stackhi=size; mstart will do the rest.
26	ts.g.stackhi = uintptr(size)
27
28	err = _cgo_try_pthread_create(&p, &attr, unsafe.Pointer(threadentry_trampolineABI0), ts)
29
30	pthread_sigmask(SIG_SETMASK, &oset, nil)
31
32	if err != 0 {
33		print("fakecgo: pthread_create failed: ")
34		println(err)
35		abort()
36	}
37}
38
39// threadentry_trampolineABI0 maps the C ABI to Go ABI then calls the Go function
40//
41//go:linkname x_threadentry_trampoline threadentry_trampoline
42var x_threadentry_trampoline byte
43var threadentry_trampolineABI0 = &x_threadentry_trampoline
44
45//go:nosplit
46func threadentry(v unsafe.Pointer) unsafe.Pointer {
47	ts := *(*ThreadStart)(v)
48	free(v)
49
50	setg_trampoline(setg_func, uintptr(unsafe.Pointer(ts.g)))
51
52	// faking funcs in go is a bit a... involved - but the following works :)
53	fn := uintptr(unsafe.Pointer(&ts.fn))
54	(*(*func())(unsafe.Pointer(&fn)))()
55
56	return nil
57}
58
59// here we will store a pointer to the provided setg func
60var setg_func uintptr
61
62// x_cgo_init(G *g, void (*setg)(void*)) (runtime/cgo/gcc_linux_amd64.c)
63// This get's called during startup, adjusts stacklo, and provides a pointer to setg_gcc for us
64// Additionally, if we set _cgo_init to non-null, go won't do it's own TLS setup
65// This function can't be go:systemstack since go is not in a state where the systemcheck would work.
66//
67//go:nosplit
68func x_cgo_init(g *G, setg uintptr) {
69	var size size_t
70	var attr *pthread_attr_t
71
72	/* The memory sanitizer distributed with versions of clang
73	   before 3.8 has a bug: if you call mmap before malloc, mmap
74	   may return an address that is later overwritten by the msan
75	   library.  Avoid this problem by forcing a call to malloc
76	   here, before we ever call malloc.
77
78	   This is only required for the memory sanitizer, so it's
79	   unfortunate that we always run it.  It should be possible
80	   to remove this when we no longer care about versions of
81	   clang before 3.8.  The test for this is
82	   misc/cgo/testsanitizers.
83
84	   GCC works hard to eliminate a seemingly unnecessary call to
85	   malloc, so we actually use the memory we allocate.  */
86
87	setg_func = setg
88	attr = (*pthread_attr_t)(malloc(unsafe.Sizeof(*attr)))
89	if attr == nil {
90		println("fakecgo: malloc failed")
91		abort()
92	}
93	pthread_attr_init(attr)
94	pthread_attr_getstacksize(attr, &size)
95	g.stacklo = uintptr(unsafe.Pointer(&size)) - uintptr(size) + 4096
96	pthread_attr_destroy(attr)
97	free(unsafe.Pointer(attr))
98}

go_linux_arm64.go RawHistoryFolder

go_linux_arm64.go Raw History Folder