diff --git a/drivers/misc/sgi-xp/xp.h b/drivers/misc/sgi-xp/xp.h
index 21cb8a31def1..867fb4863d5a 100644
--- a/drivers/misc/sgi-xp/xp.h
+++ b/drivers/misc/sgi-xp/xp.h
@@ -19,6 +19,9 @@
 #include <asm/sn/types.h>
 #include <asm/sn/bte.h>
 
+/* >>> Add this #define to some linux header file some day. */
+#define BYTES_PER_WORD	sizeof(void *)
+
 #ifdef USE_DBUG_ON
 #define DBUG_ON(condition)	BUG_ON(condition)
 #else