From 7c28f04828dc8321cb234b2ad57266b9f902add0 Mon Sep 17 00:00:00 2001
From: Nicholas Piggin <npiggin@gmail.com>
Date: Sun, 21 May 2017 23:15:43 +1000
Subject: [PATCH] powerpc/64s: Avoid saving faulting address into EX_DAR in SLB
miss
References: FATE#326523
Patch-mainline: v4.13-rc1
Git-commit: 7c28f04828dc8321cb234b2ad57266b9f902add0
The EX_DAR save area is only used in exceptional cases. With r3 no
longer clobbered by slb_allocate_realmode, saving faulting address to
EX_DAR can be deferred to those cases.
Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
arch/powerpc/kernel/exceptions-64s.S | 13 ++++++++-----
1 file changed, 8 insertions(+), 5 deletions(-)
diff --git a/arch/powerpc/kernel/exceptions-64s.S b/arch/powerpc/kernel/exceptions-64s.S
index 64365907cddc..fe3bc52aadf8 100644
--- a/arch/powerpc/kernel/exceptions-64s.S
+++ b/arch/powerpc/kernel/exceptions-64s.S
@@ -631,7 +631,6 @@ EXC_COMMON_BEGIN(slb_miss_realmode)
stw r9,PACA_EXSLB+EX_CCR(r13) /* save CR in exc. frame */
std r10,PACA_EXSLB+EX_LR(r13) /* save LR */
- std r3,PACA_EXSLB+EX_DAR(r13)
crset 4*cr0+eq
#ifdef CONFIG_PPC_STD_MMU_64
@@ -641,11 +640,10 @@ END_MMU_FTR_SECTION_IFCLR(MMU_FTR_TYPE_RADIX)
#endif
ld r10,PACA_EXSLB+EX_LR(r13)
- ld r3,PACA_EXSLB+EX_R3(r13)
lwz r9,PACA_EXSLB+EX_CCR(r13) /* get saved CR */
mtlr r10
- beq 8f /* if bad address, make full stack frame */
+ beq- 8f /* if bad address, make full stack frame */
andi. r10,r12,MSR_RI /* check for unrecoverable exception */
beq- 2f
@@ -660,6 +658,7 @@ END_MMU_FTR_SECTION_IFCLR(MMU_FTR_TYPE_RADIX)
.machine pop
RESTORE_PPR_PACA(PACA_EXSLB, r9)
+ ld r3,PACA_EXSLB+EX_R3(r13)
ld r9,PACA_EXSLB+EX_R9(r13)
ld r10,PACA_EXSLB+EX_R10(r13)
ld r11,PACA_EXSLB+EX_R11(r13)
@@ -668,7 +667,9 @@ END_MMU_FTR_SECTION_IFCLR(MMU_FTR_TYPE_RADIX)
rfid
b . /* prevent speculative execution */
-2: mfspr r11,SPRN_SRR0
+2: std r3,PACA_EXSLB+EX_DAR(r13)
+ ld r3,PACA_EXSLB+EX_R3(r13)
+ mfspr r11,SPRN_SRR0
LOAD_HANDLER(r10,unrecov_slb)
mtspr SPRN_SRR0,r10
ld r10,PACAKMSR(r13)
@@ -676,7 +677,9 @@ END_MMU_FTR_SECTION_IFCLR(MMU_FTR_TYPE_RADIX)
rfid
b .
-8: mfspr r11,SPRN_SRR0
+8: std r3,PACA_EXSLB+EX_DAR(r13)
+ ld r3,PACA_EXSLB+EX_R3(r13)
+ mfspr r11,SPRN_SRR0
LOAD_HANDLER(r10,bad_addr_slb)
mtspr SPRN_SRR0,r10
ld r10,PACAKMSR(r13)
--
2.13.7