Subject: [RFC v2 10/12] powerpc: Read AMR only if pkey-violation caused the exception.

From: Ram Pai <[email-masked]>
Date: Fri, 16 Jun 2017 20:52:42 -0700

Signed-off-by: Ram Pai <[email-masked]>
---
 arch/powerpc/kernel/exceptions-64s.S | 16 ++++++++++------
 1 file changed, 10 insertions(+), 6 deletions(-)

diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index 8db9ef8..a4de1b4 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -493,13 +493,15 @@ EXC_COMMON_BEGIN(data_access_common)
 	ld	r12,_MSR(r1)
 	ld	r3,PACA_EXGEN+EX_DAR(r13)
 	lwz	r4,PACA_EXGEN+EX_DSISR(r13)
+	std	r3,_DAR(r1)
+	std	r4,_DSISR(r1)
 #ifdef CONFIG_PPC64_MEMORY_PROTECTION_KEYS
+	andis.  r0,r4,DSISR_KEYFAULT@h /* save AMR only if its a key fault */
+	beq+	1f
 	mfspr	r5,SPRN_AMR
 	std	r5,PACA_AMR(r13)
 #endif /*  CONFIG_PPC64_MEMORY_PROTECTION_KEYS */
-	li	r5,0x300
-	std	r3,_DAR(r1)
-	std	r4,_DSISR(r1)
+1:	li	r5,0x300
 BEGIN_MMU_FTR_SECTION
 	b	do_hash_page		/* Try to handle as hpte fault */
 MMU_FTR_SECTION_ELSE
@@ -565,13 +567,15 @@ EXC_COMMON_BEGIN(instruction_access_common)
 	ld	r12,_MSR(r1)
 	ld	r3,_NIP(r1)
 	andis.	r4,r12,0x5820
+	std	r3,_DAR(r1)
+	std	r4,_DSISR(r1)
 #ifdef CONFIG_PPC64_MEMORY_PROTECTION_KEYS
+	andis.  r0,r4,DSISR_KEYFAULT@h /* save AMR only if its a key fault */
+	beq+	1f
 	mfspr	r5,SPRN_AMR
 	std	r5,PACA_AMR(r13)
 #endif /*  CONFIG_PPC64_MEMORY_PROTECTION_KEYS */
-	li	r5,0x400
-	std	r3,_DAR(r1)
-	std	r4,_DSISR(r1)
+1:	li	r5,0x400
 BEGIN_MMU_FTR_SECTION
 	b	do_hash_page		/* Try to handle as hpte fault */
 MMU_FTR_SECTION_ELSE
-- 
1.8.3.1