[PATCH 10/11] powerpc/8xx: Use SPRG2 instead of DAR for saving r3

From: Christophe Leroy
Date: Mon Apr 20 2015 - 01:27:26 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>

---
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 a073918..dbe110e 100644
--- a/arch/powerpc/kernel/head_8xx.S
+++ b/arch/powerpc/kernel/head_8xx.S
@@ -310,7 +310,7 @@ SystemCall:
InstructionTLBMiss:
EXCEPTION_PROLOG_0
#ifdef CONFIG_8xx_CPU6
- mtspr SPRN_DAR, r3
+ mtspr SPRN_SPRG_SCRATCH2, r3
#endif

/* If we are faulting a kernel address, we have to use the
@@ -374,8 +374,7 @@ 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
@@ -388,7 +387,7 @@ DataStoreTLBMiss:
* kernel page tables.
*/
#ifdef CONFIG_8xx_CPU6
- mtspr SPRN_DAR, r3
+ mtspr SPRN_SPRG_SCRATCH2, r3
mfcr r3
mfspr r10, SPRN_MD_EPN
andis. r11, r10, 0x8000
@@ -461,7 +460,7 @@ 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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