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| author | Christophe Leroy <christophe.leroy@c-s.fr> | 2016-02-09 17:07:48 +0100 |
|---|---|---|
| committer | Scott Wood <oss@buserror.net> | 2016-03-11 17:18:01 -0600 |
| commit | 913a6b3d10d85a032eff2f31254c35e0976f5e32 (patch) | |
| tree | db23606c7e07020add9bfd29f9b65dbdc761481c | |
| parent | 3b5eb41b8ce0a8be1e0da0f3f0f91cc29f4fcb16 (diff) | |
| download | blackbird-op-linux-913a6b3d10d85a032eff2f31254c35e0976f5e32.tar.gz blackbird-op-linux-913a6b3d10d85a032eff2f31254c35e0976f5e32.zip | |
powerpc/8xx: Save r3 all the time in DTLB miss handler
We are spending between 40 and 160 cycles with a mean of 65 cycles in
the DTLB handling routine (measured with mftbl) so make it more
simple althought it adds one instruction.
With this modification, we get three registers available at all time,
which will help with following patch.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Scott Wood <oss@buserror.net>
| -rw-r--r-- | arch/powerpc/kernel/head_8xx.S | 13 |
1 files changed, 4 insertions, 9 deletions
diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S index e629e28b57e1..a89492eb6e46 100644 --- a/arch/powerpc/kernel/head_8xx.S +++ b/arch/powerpc/kernel/head_8xx.S @@ -385,23 +385,20 @@ InstructionTLBMiss: . = 0x1200 DataStoreTLBMiss: -#ifdef CONFIG_8xx_CPU6 mtspr SPRN_SPRG_SCRATCH2, r3 -#endif EXCEPTION_PROLOG_0 - mfcr r10 + mfcr r3 /* If we are faulting a kernel address, we have to use the * kernel page tables. */ - mfspr r11, SPRN_MD_EPN - IS_KERNEL(r11, r11) + mfspr r10, SPRN_MD_EPN + IS_KERNEL(r11, r10) 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_MD_EPN + mtcr r3 /* Insert level 1 index */ rlwimi r11, r10, 32 - ((PAGE_SHIFT - 2) << 1), (PAGE_SHIFT - 2) << 1, 29 @@ -453,9 +450,7 @@ DataStoreTLBMiss: MTSPR_CPU6(SPRN_MD_RPN, r10, r3) /* Update TLB entry */ /* Restore registers */ -#ifdef CONFIG_8xx_CPU6 mfspr r3, SPRN_SPRG_SCRATCH2 -#endif mtspr SPRN_DAR, r11 /* Tag DAR */ EXCEPTION_EPILOG_0 rfi |
