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Subject[PATCH v2 13/25] powerpc/8xx: also use r3 in the ITLB miss in all situations
Date
We are spending between 40 and 160 cycles with a mean of 65 cycles
in the TLB handling routines (measured with mftbl) so make it more
simple althought it adds one instruction

Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
---
No change in v2

arch/powerpc/kernel/head_8xx.S | 15 ++++-----------
1 file changed, 4 insertions(+), 11 deletions(-)

diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S
index 1238fbe..6c991e9 100644
--- a/arch/powerpc/kernel/head_8xx.S
+++ b/arch/powerpc/kernel/head_8xx.S
@@ -352,30 +352,25 @@ SystemCall:
#endif

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

/* If we are faulting a kernel address, we have to use the
* kernel page tables.
*/
+ mfspr r10, SPRN_SRR0 /* Get effective address of fault */
+ INVALIDATE_ADJACENT_PAGES_CPU15(r11, r10)
#ifdef CONFIG_MODULES
/* Only modules will cause ITLB Misses as we always
* pin the first 8MB of kernel memory */
- mfspr r11, SPRN_SRR0 /* Get effective address of fault */
- INVALIDATE_ADJACENT_PAGES_CPU15(r10, r11)
- mfcr r10
+ mfcr r3
IS_KERNEL(r11, r11)
mfspr r11, SPRN_M_TW /* Get level 1 table */
BRANCH_UNLESS_KERNEL(3f)
lis r11, (swapper_pg_dir-PAGE_OFFSET)@ha
3:
- mtcr r10
- mfspr r10, SPRN_SRR0 /* Get effective address of fault */
+ mtcr r3
#else
- mfspr r10, SPRN_SRR0 /* Get effective address of fault */
- INVALIDATE_ADJACENT_PAGES_CPU15(r11, r10)
mfspr r11, SPRN_M_TW /* Get level 1 table base address */
#endif
/* Insert level 1 index */
@@ -408,9 +403,7 @@ InstructionTLBMiss:
MTSPR_CPU6(SPRN_MI_RPN, r10, r3) /* Update TLB entry */

/* Restore registers */
-#ifdef CONFIG_8xx_CPU6
mfspr r3, SPRN_SPRG_SCRATCH2
-#endif
EXCEPTION_EPILOG_0
rfi

--
2.1.0


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