diff --git a/sys/arch/powerpc/powerpc/db_interface.c b/sys/arch/powerpc/powerpc/db_interface.c
index 24a36a3c729a..ca39b2bae50b 100644
--- a/sys/arch/powerpc/powerpc/db_interface.c
+++ b/sys/arch/powerpc/powerpc/db_interface.c
@@ -1,8 +1,8 @@
-/*	$NetBSD: db_interface.c,v 1.31 2003/09/27 04:44:42 matt Exp $ */
+/*	$NetBSD: db_interface.c,v 1.32 2003/10/09 07:12:24 matt Exp $ */
 /*	$OpenBSD: db_interface.c,v 1.2 1996/12/28 06:21:50 rahnds Exp $	*/
 
 #include <sys/cdefs.h>
-__KERNEL_RCSID(0, "$NetBSD: db_interface.c,v 1.31 2003/09/27 04:44:42 matt Exp $");
+__KERNEL_RCSID(0, "$NetBSD: db_interface.c,v 1.32 2003/10/09 07:12:24 matt Exp $");
 
 #define USERACC
 
@@ -76,9 +76,11 @@ ddb_trap_glue(struct trapframe *frame)
 		return kdb_trap(frame->exc, frame);
 #else /* PPC_OEA */
 	if ((frame->srr1 & PSL_PR) == 0 &&
-	    (frame->exc == EXC_TRC || frame->exc == EXC_RUNMODETRC ||
+	    (frame->exc == EXC_TRC ||
+	     frame->exc == EXC_RUNMODETRC ||
 	     (frame->exc == EXC_PGM && (frame->srr1 & 0x20000)) ||
-	     frame->exc == EXC_BPT)) {
+	     frame->exc == EXC_BPT ||
+	     frame->exc == EXC_DSI)) {
 		int type = frame->exc;
 		if (type == EXC_PGM && (frame->srr1 & 0x20000)) {
 			type = T_BREAKPOINT;
diff --git a/sys/arch/powerpc/powerpc/trap_subr.S b/sys/arch/powerpc/powerpc/trap_subr.S
index d53dac4c8e17..90bd03d09a0e 100644
--- a/sys/arch/powerpc/powerpc/trap_subr.S
+++ b/sys/arch/powerpc/powerpc/trap_subr.S
@@ -1,4 +1,4 @@
-/*	$NetBSD: trap_subr.S,v 1.49 2003/08/12 15:40:02 matt Exp $	*/
+/*	$NetBSD: trap_subr.S,v 1.50 2003/10/09 07:12:24 matt Exp $	*/
 
 /*
  * Copyright (C) 1995, 1996 Wolfgang Solfrank.
@@ -805,6 +805,35 @@ disitrap:
 	streg	%r30,(CI_TEMPSAVE+CPUSAVE_DAR)(%r1)
 	streg	%r31,(CI_TEMPSAVE+CPUSAVE_DSISR)(%r1)
 
+#ifdef DDB
+	mfsrr1	%r31
+	mtcr	%r31
+	bt	17,trapstart		/* branch is user mode */
+	mfsprg1	%r31			/* get old SP */
+#if 0
+	subf	%r30,%r30,%r31		/* subtract DAR from it */
+	addi	%r30,%r30,2048		/* offset result 1/2 page */
+	cmplwi	%cr0,%r30,4096		/* is DAR +- 1/2 page of SP? */
+#else
+	xor.	%r30,%r30,%r31		/* try xor most significant bits */
+	cmplwi	%cr0,%r30,4096		/* is DAR on same page as SP? */
+#endif
+	bge	%cr0,trapstart		/* no, too far away. */
+	/* Now convert this DSI into a DDB trap.  */
+	GET_CPUINFO(%r1)
+	ldreg	%r30,(CI_DISISAVE+CPUSAVE_R28)(%r1) /* get  r28 */
+	streg	%r30,(CI_DDBSAVE +CPUSAVE_R28)(%r1) /* save r28 */
+	ldreg	%r31,(CI_DISISAVE+CPUSAVE_R29)(%r1) /* get  r29 */
+	streg	%r31,(CI_DDBSAVE +CPUSAVE_R29)(%r1) /* save r29 */
+	ldreg	%r30,(CI_DISISAVE+CPUSAVE_R30)(%r1) /* get  r30 */
+	streg	%r30,(CI_DDBSAVE +CPUSAVE_R30)(%r1) /* save r30 */
+	ldreg	%r31,(CI_DISISAVE+CPUSAVE_R31)(%r1) /* get  r31 */
+	streg	%r31,(CI_DDBSAVE +CPUSAVE_R31)(%r1) /* save r31 */
+	lis	%r1,ddbstk+INTSTK@ha	/* get new SP */
+	addi	%r1,%r1,ddbstk+INTSTK@l
+	b	ddbtrap
+#endif
+
 	.globl	_C_LABEL(trapstart)
 	.type	_C_LABEL(trapstart),@function
 _C_LABEL(trapstart):