github.com/ebitengine/purego@v0.8.0-alpha.2.0.20240512170805-6cd12240d332/internal/fakecgo/go_freebsd_arm64.go (about) 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 7 package fakecgo 8 9 import "unsafe" 10 11 //go:nosplit 12 func _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 42 var x_threadentry_trampoline byte 43 var threadentry_trampolineABI0 = &x_threadentry_trampoline 44 45 //go:nosplit 46 func 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 60 var 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 68 func 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 }