diff --git a/src/vendor/golang.org/x/sys/cpu/cpu_riscv64.go b/src/vendor/golang.org/x/sys/cpu/cpu_riscv64.go
new file mode 100644
index 0000000000..fe9feb7980
--- /dev/null
+++ b/src/vendor/golang.org/x/sys/cpu/cpu_riscv64.go
@@ -0,0 +1,11 @@
+// Copyright 2020 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 riscv64
+
+package cpu
+
+const cacheLineSize = 32
+
+func doinit() {}