runtime: add file copyright header declaration

Some files have no copyright notice.
The copyright time is the earliest modification record of the file.

Change-Id: I5698bae16b6b73543e074415877a03348f792951
Reviewed-on: https://go-review.googlesource.com/c/go/+/246378
Run-TryBot: Emmanuel Odeke <emm.odeke@gmail.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Emmanuel Odeke <emm.odeke@gmail.com>
diff --git a/src/runtime/defs_linux_arm.go b/src/runtime/defs_linux_arm.go
index ea29fd9..5bc0916 100644
--- a/src/runtime/defs_linux_arm.go
+++ b/src/runtime/defs_linux_arm.go
@@ -1,3 +1,7 @@
+// 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
 
 // Constants
diff --git a/src/runtime/defs_linux_mips64x.go b/src/runtime/defs_linux_mips64x.go
index 0fb53d5..1fb423b 100644
--- a/src/runtime/defs_linux_mips64x.go
+++ b/src/runtime/defs_linux_mips64x.go
@@ -1,3 +1,7 @@
+// 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.
+
 // +build mips64 mips64le
 // +build linux
 
diff --git a/src/runtime/defs_openbsd_arm64.go b/src/runtime/defs_openbsd_arm64.go
index 8b8d5cd..628f4bc 100644
--- a/src/runtime/defs_openbsd_arm64.go
+++ b/src/runtime/defs_openbsd_arm64.go
@@ -1,3 +1,7 @@
+// Copyright 2019 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
 
 import "unsafe"
diff --git a/src/runtime/defs_plan9_386.go b/src/runtime/defs_plan9_386.go
index 220169d..49129b3 100644
--- a/src/runtime/defs_plan9_386.go
+++ b/src/runtime/defs_plan9_386.go
@@ -1,3 +1,7 @@
+// 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
 
 const _PAGESIZE = 0x1000
diff --git a/src/runtime/defs_plan9_amd64.go b/src/runtime/defs_plan9_amd64.go
index 29a2643..0099563 100644
--- a/src/runtime/defs_plan9_amd64.go
+++ b/src/runtime/defs_plan9_amd64.go
@@ -1,3 +1,7 @@
+// 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
 
 const _PAGESIZE = 0x1000
diff --git a/src/runtime/rt0_linux_ppc64.s b/src/runtime/rt0_linux_ppc64.s
index 1265b15..897d610 100644
--- a/src/runtime/rt0_linux_ppc64.s
+++ b/src/runtime/rt0_linux_ppc64.s
@@ -1,3 +1,7 @@
+// Copyright 2016 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.
+
 #include "textflag.h"
 
 // actually a function descriptor for _main<>(SB)
diff --git a/src/runtime/rt0_linux_ppc64le.s b/src/runtime/rt0_linux_ppc64le.s
index 54ea9d5..4f7c6e6 100644
--- a/src/runtime/rt0_linux_ppc64le.s
+++ b/src/runtime/rt0_linux_ppc64le.s
@@ -1,3 +1,7 @@
+// Copyright 2016 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.
+
 #include "go_asm.h"
 #include "textflag.h"
 
diff --git a/src/runtime/trace/annotation.go b/src/runtime/trace/annotation.go
index 82cb232..6e18bfb 100644
--- a/src/runtime/trace/annotation.go
+++ b/src/runtime/trace/annotation.go
@@ -1,3 +1,7 @@
+// Copyright 2018 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 trace
 
 import (
diff --git a/src/runtime/trace/annotation_test.go b/src/runtime/trace/annotation_test.go
index 71abbfc..31fccef 100644
--- a/src/runtime/trace/annotation_test.go
+++ b/src/runtime/trace/annotation_test.go
@@ -1,3 +1,7 @@
+// Copyright 2018 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 trace_test
 
 import (