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| author | Christophe Leroy <christophe.leroy@c-s.fr> | 2018-01-12 13:45:23 +0100 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2018-01-16 23:47:12 +1100 |
| commit | cd99ddbea250ee79027df6c469f51ad9e5452738 (patch) | |
| tree | bdf7792780f06be984ec2cc200eb725dd10b7a4a /arch/powerpc/kernel/head_8xx.S | |
| parent | bb9b5a8332533ac7935ca6edfc7ebf15a5366f11 (diff) | |
| download | linux-cd99ddbea250ee79027df6c469f51ad9e5452738.tar.bz2 | |
powerpc/8xx: Only perform perf counting when perf is in use.
In TLB miss handlers, updating the perf counter is only useful
when performing a perf analysis. As it has a noticeable overhead,
let's only do it when needed.
In order to do so, the exit of the miss handlers will be patched
when starting/stopping 'perf': the first register restore
instruction of each exit point will be replaced by a jump to
the counting code.
Once this is done, CONFIG_PPC_8xx_PERF_EVENT becomes useless as
this feature doesn't add any overhead.
Signed-off-by: Christophe Leroy <christophe.leroy@c-s.fr>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/kernel/head_8xx.S')
| -rw-r--r-- | arch/powerpc/kernel/head_8xx.S | 47 |
1 files changed, 32 insertions, 15 deletions
diff --git a/arch/powerpc/kernel/head_8xx.S b/arch/powerpc/kernel/head_8xx.S index eda582b96dbf..641c9a9d4db2 100644 --- a/arch/powerpc/kernel/head_8xx.S +++ b/arch/powerpc/kernel/head_8xx.S @@ -304,12 +304,6 @@ InstructionTLBMiss: #if defined(ITLB_MISS_KERNEL) || defined(CONFIG_HUGETLB_PAGE) mtspr SPRN_SPRG_SCRATCH2, r12 #endif -#ifdef CONFIG_PPC_8xx_PERF_EVENT - lis r10, (itlb_miss_counter - PAGE_OFFSET)@ha - lwz r11, (itlb_miss_counter - PAGE_OFFSET)@l(r10) - addi r11, r11, 1 - stw r11, (itlb_miss_counter - PAGE_OFFSET)@l(r10) -#endif /* If we are faulting a kernel address, we have to use the * kernel page tables. @@ -392,6 +386,20 @@ _ENTRY(ITLBMiss_cmp) mtspr SPRN_MI_RPN, r10 /* Update TLB entry */ /* Restore registers */ +_ENTRY(itlb_miss_exit_1) + mfspr r10, SPRN_SPRG_SCRATCH0 + mfspr r11, SPRN_SPRG_SCRATCH1 +#if defined(ITLB_MISS_KERNEL) || defined(CONFIG_HUGETLB_PAGE) + mfspr r12, SPRN_SPRG_SCRATCH2 +#endif + rfi +#ifdef CONFIG_PERF_EVENTS +_ENTRY(itlb_miss_perf) + lis r10, (itlb_miss_counter - PAGE_OFFSET)@ha + lwz r11, (itlb_miss_counter - PAGE_OFFSET)@l(r10) + addi r11, r11, 1 + stw r11, (itlb_miss_counter - PAGE_OFFSET)@l(r10) +#endif mfspr r10, SPRN_SPRG_SCRATCH0 mfspr r11, SPRN_SPRG_SCRATCH1 #if defined(ITLB_MISS_KERNEL) || defined(CONFIG_HUGETLB_PAGE) @@ -429,12 +437,6 @@ DataStoreTLBMiss: mtspr SPRN_SPRG_SCRATCH0, r10 mtspr SPRN_SPRG_SCRATCH1, r11 mtspr SPRN_SPRG_SCRATCH2, r12 -#ifdef CONFIG_PPC_8xx_PERF_EVENT - lis r10, (dtlb_miss_counter - PAGE_OFFSET)@ha - lwz r11, (dtlb_miss_counter - PAGE_OFFSET)@l(r10) - addi r11, r11, 1 - stw r11, (dtlb_miss_counter - PAGE_OFFSET)@l(r10) -#endif mfcr r12 /* If we are faulting a kernel address, we have to use the @@ -526,6 +528,18 @@ _ENTRY(DTLBMiss_jmp) /* Restore registers */ mtspr SPRN_DAR, r11 /* Tag DAR */ +_ENTRY(dtlb_miss_exit_1) + mfspr r10, SPRN_SPRG_SCRATCH0 + mfspr r11, SPRN_SPRG_SCRATCH1 + mfspr r12, SPRN_SPRG_SCRATCH2 + rfi +#ifdef CONFIG_PERF_EVENTS +_ENTRY(dtlb_miss_perf) + lis r10, (dtlb_miss_counter - PAGE_OFFSET)@ha + lwz r11, (dtlb_miss_counter - PAGE_OFFSET)@l(r10) + addi r11, r11, 1 + stw r11, (dtlb_miss_counter - PAGE_OFFSET)@l(r10) +#endif mfspr r10, SPRN_SPRG_SCRATCH0 mfspr r11, SPRN_SPRG_SCRATCH1 mfspr r12, SPRN_SPRG_SCRATCH2 @@ -635,7 +649,7 @@ DataBreakpoint: mfspr r11, SPRN_SPRG_SCRATCH1 rfi -#ifdef CONFIG_PPC_8xx_PERF_EVENT +#ifdef CONFIG_PERF_EVENTS . = 0x1d00 InstructionBreakpoint: mtspr SPRN_SPRG_SCRATCH0, r10 @@ -675,6 +689,7 @@ DTLBMissIMMR: li r11, RPN_PATTERN mtspr SPRN_DAR, r11 /* Tag DAR */ +_ENTRY(dtlb_miss_exit_2) mfspr r10, SPRN_SPRG_SCRATCH0 mfspr r11, SPRN_SPRG_SCRATCH1 mfspr r12, SPRN_SPRG_SCRATCH2 @@ -692,6 +707,7 @@ DTLBMissLinear: li r11, RPN_PATTERN mtspr SPRN_DAR, r11 /* Tag DAR */ +_ENTRY(dtlb_miss_exit_3) mfspr r10, SPRN_SPRG_SCRATCH0 mfspr r11, SPRN_SPRG_SCRATCH1 mfspr r12, SPRN_SPRG_SCRATCH2 @@ -708,6 +724,7 @@ ITLBMissLinear: _PAGE_PRESENT mtspr SPRN_MI_RPN, r10 /* Update TLB entry */ +_ENTRY(itlb_miss_exit_2) mfspr r10, SPRN_SPRG_SCRATCH0 mfspr r11, SPRN_SPRG_SCRATCH1 mfspr r12, SPRN_SPRG_SCRATCH2 @@ -1039,7 +1056,7 @@ initial_mmu: #endif /* Disable debug mode entry on breakpoints */ mfspr r8, SPRN_DER -#ifdef CONFIG_PPC_8xx_PERF_EVENT +#ifdef CONFIG_PERF_EVENTS rlwinm r8, r8, 0, ~0xc #else rlwinm r8, r8, 0, ~0x8 @@ -1072,7 +1089,7 @@ swapper_pg_dir: abatron_pteptrs: .space 8 -#ifdef CONFIG_PPC_8xx_PERF_EVENT +#ifdef CONFIG_PERF_EVENTS .globl itlb_miss_counter itlb_miss_counter: .space 4 |