diff --git a/arch/m32r/include/asm/socket.h b/arch/m32r/include/asm/socket.h
index d36f592..3390a86 100644
--- a/arch/m32r/include/asm/socket.h
+++ b/arch/m32r/include/asm/socket.h
@@ -58,5 +58,6 @@
 #define SCM_TIMESTAMPING	SO_TIMESTAMPING
 
 #define SO_PROTOCOL		38
+#define SO_DOMAIN		39
 
 #endif /* _ASM_M32R_SOCKET_H */