[PATCH v4 4/5] powerpc/8xx: Use SPRG2 instead of DAR for saving r3

From: Christophe Leroy
Date: Wed Feb 04 2015 - 09:49:22 EST


We now have SPRG2 available as in it not used anymore for saving CR, so we don't
need to crash DAR anymore for saving r3 for CPU6 ERRATA handling.

Signed-off-by: Christophe Leroy <christophe.leroy@xxxxxx>

---
v2: no change
v3: no change
v4: Respined against scootwood.git next (0dc294f7)

arch/powerpc/kernel/head_8xx.S | 9 ++++-----
1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S
index 150d03f..ba2dc53 100644
--- a/arch/powerpc/kernel/head_8xx.S
+++ b/arch/powerpc/kernel/head_8xx.S
@@ -309,7 +309,7 @@ SystemCall:

InstructionTLBMiss:
#ifdef CONFIG_8xx_CPU6
- mtspr SPRN_DAR, r3
+ mtspr SPRN_SPRG_SCRATCH2, r3
#endif
EXCEPTION_PROLOG_0

@@ -362,8 +362,7 @@ InstructionTLBMiss:

/* Restore registers */
#ifdef CONFIG_8xx_CPU6
- mfspr r3, SPRN_DAR
- mtspr SPRN_DAR, r11 /* Tag DAR */
+ mfspr r3, SPRN_SPRG_SCRATCH2
#endif
EXCEPTION_EPILOG_0
rfi
@@ -371,7 +370,7 @@ InstructionTLBMiss:
. = 0x1200
DataStoreTLBMiss:
#ifdef CONFIG_8xx_CPU6
- mtspr SPRN_DAR, r3
+ mtspr SPRN_SPRG_SCRATCH2, r3
#endif
EXCEPTION_PROLOG_0
mfcr r10
@@ -438,7 +437,7 @@ DataStoreTLBMiss:

/* Restore registers */
#ifdef CONFIG_8xx_CPU6
- mfspr r3, SPRN_DAR
+ mfspr r3, SPRN_SPRG_SCRATCH2
#endif
mtspr SPRN_DAR, r11 /* Tag DAR */
EXCEPTION_EPILOG_0
--
2.1.0

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