runtime: darwin/arm64 support

Change-Id: I3b3f80791a1db4c2b7318f81a115972cd2237f03
Signed-off-by: Shenghou Ma <minux@golang.org>
Reviewed-on: https://go-review.googlesource.com/8782
Reviewed-by: David Crawshaw <crawshaw@golang.org>

1 files changed, 13 insertions, 0 deletions

diff --git a/src/runtime/os_darwin_arm64.go b/src/runtime/os_darwin_arm64.go
new file mode 100644
index 0000000000..4d35af9c6a
--- /dev/null
+++ b/src/runtime/os_darwin_arm64.go
@@ -0,0 +1,13 @@
+// Copyright 2014 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
+
+//go:nosplit
+func cputicks() int64 {
+	// Currently cputicks() is used in blocking profiler and to seed runtime·fastrand1().
+	// runtime·nanotime() is a poor approximation of CPU ticks that is enough for the profiler.
+	// TODO: need more entropy to better seed fastrand1.
+	return nanotime()
+}