diff --git a/sys/arch/sparc64/include/pmap.h b/sys/arch/sparc64/include/pmap.h
index 5d89b992a90f..a9edec7244d8 100644
--- a/sys/arch/sparc64/include/pmap.h
+++ b/sys/arch/sparc64/include/pmap.h
@@ -1,4 +1,4 @@
-/*	$NetBSD: pmap.h,v 1.10 1999/06/07 05:28:04 eeh Exp $	*/
+/*	$NetBSD: pmap.h,v 1.11 1999/12/30 16:21:25 eeh Exp $	*/
 
 /*-
  * Copyright (C) 1995, 1996 Wolfgang Solfrank.
@@ -162,6 +162,8 @@ int pmap_count_res __P((pmap_t pmap));
 #define	pmap_phys_address(x)		((((paddr_t)(x))<<PGSHIFT)|PMAP_NC)
 
 void pmap_bootstrap __P((u_long kernelstart, u_long kernelend, u_int numctx));
+/* make sure all page mappings are modulo 16K to prevent d$ aliasing */
+#define PMAP_PREFER(pa, va)	(*(va)+=(((*(va))^(pa))&(1<<(PGSHIFT+1))))
 
 /* SPARC specific? */
 void		pmap_redzone __P((void));