[RFC PATCH 17/17] powerpc: Save DAR and DSISR in pt_regs on MCE

["Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>]

From: "Aneesh Kumar K.V" <aneesh.kumar@linux.vnet.ibm.com>

We were not saving DAR and DSISR on MCE. Save then and also print the values
along with exception details in xmon.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
---
 arch/powerpc/kernel/exceptions-64s.S |    9 +++++++++
 arch/powerpc/xmon/xmon.c             |    2 +-
 2 files changed, 10 insertions(+), 1 deletion(-)

diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index 0e9c48c..d02e730 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -640,9 +640,18 @@ slb_miss_user_pseries:
 	.align	7
 	.globl machine_check_common
 machine_check_common:
+
+	mfspr	r10,SPRN_DAR
+	std	r10,PACA_EXGEN+EX_DAR(r13)
+	mfspr	r10,SPRN_DSISR
+	stw	r10,PACA_EXGEN+EX_DSISR(r13)
 	EXCEPTION_PROLOG_COMMON(0x200, PACA_EXMC)
 	FINISH_NAP
 	DISABLE_INTS
+	ld	r3,PACA_EXGEN+EX_DAR(r13)
+	lwz	r4,PACA_EXGEN+EX_DSISR(r13)
+	std	r3,_DAR(r1)
+	std	r4,_DSISR(r1)
 	bl	.save_nvgprs
 	addi	r3,r1,STACK_FRAME_OVERHEAD
 	bl	.machine_check_exception
diff --git a/arch/powerpc/xmon/xmon.c b/arch/powerpc/xmon/xmon.c
index 1f8d2f1..a72e490 100644
--- a/arch/powerpc/xmon/xmon.c
+++ b/arch/powerpc/xmon/xmon.c
@@ -1423,7 +1423,7 @@ static void excprint(struct pt_regs *fp)
 	printf("    sp: %lx\n", fp->gpr[1]);
 	printf("   msr: %lx\n", fp->msr);
 
-	if (trap == 0x300 || trap == 0x380 || trap == 0x600) {
+	if (trap == 0x300 || trap == 0x380 || trap == 0x600 || trap == 0x200) {
 		printf("   dar: %lx\n", fp->dar);
 		if (trap != 0x380)
 			printf(" dsisr: %lx\n", fp->dsisr);
-- 
1.7.10