diff --git a/arch/sandbox/include/asm/bitops.h b/arch/sandbox/include/asm/bitops.h
index e807c4e..f1a7aee 100644
--- a/arch/sandbox/include/asm/bitops.h
+++ b/arch/sandbox/include/asm/bitops.h
@@ -1,6 +1,8 @@
 /*
  * Copyright (c) 2011 The Chromium OS Authors.
  *
+ * Modified from Linux arch/arm/include/asm/bitops.h
+ *
  * Copyright 1995, Russell King.
  * Various bits and pieces copyrights include:
  *  Linus Torvalds (test_bit).