1 files changed, 67 insertions, 0 deletions
diff --git a/src/runtime/cgo_mmap.go b/src/runtime/cgo_mmap.go
new file mode 100644
index 0000000..d5e0cc1
--- /dev/null
+++ b/src/runtime/cgo_mmap.go
@@ -0,0 +1,67 @@
+// Copyright 2015 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.
+
+// Support for memory sanitizer. See runtime/cgo/mmap.go.
+
+// +build linux,amd64 linux,arm64
+
+package runtime
+
+import "unsafe"
+
+// _cgo_mmap is filled in by runtime/cgo when it is linked into the
+// program, so it is only non-nil when using cgo.
+//go:linkname _cgo_mmap _cgo_mmap
+var _cgo_mmap unsafe.Pointer
+
+// _cgo_munmap is filled in by runtime/cgo when it is linked into the
+// program, so it is only non-nil when using cgo.
+//go:linkname _cgo_munmap _cgo_munmap
+var _cgo_munmap unsafe.Pointer
+
+// mmap is used to route the mmap system call through C code when using cgo, to
+// support sanitizer interceptors. Don't allow stack splits, since this function
+// (used by sysAlloc) is called in a lot of low-level parts of the runtime and
+// callers often assume it won't acquire any locks.
+//go:nosplit
+func mmap(addr unsafe.Pointer, n uintptr, prot, flags, fd int32, off uint32) (unsafe.Pointer, int) {
+	if _cgo_mmap != nil {
+		// Make ret a uintptr so that writing to it in the
+		// function literal does not trigger a write barrier.
+		// A write barrier here could break because of the way
+		// that mmap uses the same value both as a pointer and
+		// an errno value.
+		var ret uintptr
+		systemstack(func() {
+			ret = callCgoMmap(addr, n, prot, flags, fd, off)
+		})
+		if ret < 4096 {
+			return nil, int(ret)
+		}
+		return unsafe.Pointer(ret), 0
+	}
+	return sysMmap(addr, n, prot, flags, fd, off)
+}
+
+func munmap(addr unsafe.Pointer, n uintptr) {
+	if _cgo_munmap != nil {
+		systemstack(func() { callCgoMunmap(addr, n) })
+		return
+	}
+	sysMunmap(addr, n)
+}
+
+// sysMmap calls the mmap system call. It is implemented in assembly.
+func sysMmap(addr unsafe.Pointer, n uintptr, prot, flags, fd int32, off uint32) (p unsafe.Pointer, err int)
+
+// callCgoMmap calls the mmap function in the runtime/cgo package
+// using the GCC calling convention. It is implemented in assembly.
+func callCgoMmap(addr unsafe.Pointer, n uintptr, prot, flags, fd int32, off uint32) uintptr
+
+// sysMunmap calls the munmap system call. It is implemented in assembly.
+func sysMunmap(addr unsafe.Pointer, n uintptr)
+
+// callCgoMunmap calls the munmap function in the runtime/cgo package
+// using the GCC calling convention. It is implemented in assembly.
+func callCgoMunmap(addr unsafe.Pointer, n uintptr)