We have to set the pagetable pointers with the atomic swap instruction.

From NetBSD. (actually from a paper I read recently, but since NetBSD
already did that it was easier to grab the code from them)

2 files changed, 9 insertions, 3 deletions

diff --git a/sys/arch/sparc/sparc/asm.h b/sys/arch/sparc/sparc/asm.h
index 534853ce491..3258be1e584 100644
--- a/sys/arch/sparc/sparc/asm.h
+++ b/sys/arch/sparc/sparc/asm.h
@@ -1,4 +1,4 @@
-/*	$OpenBSD: asm.h,v 1.2 1997/08/08 08:26:58 downsj Exp $	*/
+/*	$OpenBSD: asm.h,v 1.3 1999/09/03 18:11:28 art Exp $	*/
 /*	$NetBSD: asm.h,v 1.4 1996/07/01 18:01:26 abrown Exp $ */
 
 /*
@@ -117,3 +117,9 @@
 	__asm __volatile("stda %0,[%1]%2" : : \
 	    "r" ((long long)(value)), "r" ((int)(loc)), "n" (asi)); \
 })
+
+/* atomic swap of a word between a register and memory */
+#define swap(loc, val) ({ \
+        __asm __volatile("swap [%2],%0" : "=&r" (val) : "0" (val), "r" (loc)); \
+})
+
diff --git a/sys/arch/sparc/sparc/pmap.c b/sys/arch/sparc/sparc/pmap.c
index 1867c14bcff..0416d02833f 100644
--- a/sys/arch/sparc/sparc/pmap.c
+++ b/sys/arch/sparc/sparc/pmap.c
@@ -1,4 +1,4 @@
-/*	$OpenBSD: pmap.c,v 1.32 1999/09/03 18:01:59 art Exp $	*/
+/*	$OpenBSD: pmap.c,v 1.33 1999/09/03 18:11:29 art Exp $	*/
 /*	$NetBSD: pmap.c,v 1.118 1998/05/19 19:00:18 thorpej Exp $ */
 
 /*
@@ -612,7 +612,7 @@ setpgt4m(ptep, pte)
 	int *ptep;
 	int pte;
 {
-	*ptep = pte;
+	swap(ptep, pte);
 	if ((cpuinfo.flags & CPUFLG_CACHEPAGETABLES) == 0)
 		cpuinfo.pcache_flush_line((int)ptep, VA2PA((caddr_t)ptep));
 }