From: Christophe Leroy Date: Fri, 12 Jan 2018 12:45:23 +0000 (+0100) Subject: powerpc/8xx: Only perform perf counting when perf is in use. X-Git-Tag: v4.16-rc1~93^2~140 X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=cd99ddbea250ee79027df6c469f51ad9e5452738;p=linux.git 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 Signed-off-by: Michael Ellerman --- diff --git a/arch/powerpc/include/asm/ppc-opcode.h b/arch/powerpc/include/asm/ppc-opcode.h index ce0930d68857..ab5c1588b487 100644 --- a/arch/powerpc/include/asm/ppc-opcode.h +++ b/arch/powerpc/include/asm/ppc-opcode.h @@ -236,6 +236,7 @@ #define PPC_INST_RFCI 0x4c000066 #define PPC_INST_RFDI 0x4c00004e #define PPC_INST_RFMCI 0x4c00004c +#define PPC_INST_MFSPR 0x7c0002a6 #define PPC_INST_MFSPR_DSCR 0x7c1102a6 #define PPC_INST_MFSPR_DSCR_MASK 0xfc1ffffe #define PPC_INST_MTSPR_DSCR 0x7c1103a6 @@ -383,6 +384,7 @@ #define __PPC_ME64(s) __PPC_MB64(s) #define __PPC_BI(s) (((s) & 0x1f) << 16) #define __PPC_CT(t) (((t) & 0x0f) << 21) +#define __PPC_SPR(r) ((((r) & 0x1f) << 16) | ((((r) >> 5) & 0x1f) << 11)) /* * Only use the larx hint bit on 64bit CPUs. e500v1/v2 based CPUs will treat a diff --git a/arch/powerpc/kernel/entry_32.S b/arch/powerpc/kernel/entry_32.S index e780e1fbf6c2..eb8d01bae8c6 100644 --- a/arch/powerpc/kernel/entry_32.S +++ b/arch/powerpc/kernel/entry_32.S @@ -211,7 +211,7 @@ transfer_to_handler_cont: mflr r9 lwz r11,0(r9) /* virtual address of handler */ lwz r9,4(r9) /* where to go when done */ -#ifdef CONFIG_PPC_8xx_PERF_EVENT +#if defined(CONFIG_PPC_8xx) && defined(CONFIG_PERF_EVENTS) mtspr SPRN_NRI, r0 #endif #ifdef CONFIG_TRACE_IRQFLAGS @@ -301,7 +301,7 @@ stack_ovf: lis r9,StackOverflow@ha addi r9,r9,StackOverflow@l LOAD_MSR_KERNEL(r10,MSR_KERNEL) -#ifdef CONFIG_PPC_8xx_PERF_EVENT +#if defined(CONFIG_PPC_8xx) && defined(CONFIG_PERF_EVENTS) mtspr SPRN_NRI, r0 #endif mtspr SPRN_SRR0,r9 @@ -430,7 +430,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_NEED_PAIRED_STWCX) lwz r7,_NIP(r1) lwz r2,GPR2(r1) lwz r1,GPR1(r1) -#ifdef CONFIG_PPC_8xx_PERF_EVENT +#if defined(CONFIG_PPC_8xx) && defined(CONFIG_PERF_EVENTS) mtspr SPRN_NRI, r0 #endif mtspr SPRN_SRR0,r7 @@ -727,7 +727,7 @@ fast_exception_return: lwz r10,_LINK(r11) mtlr r10 REST_GPR(10, r11) -#ifdef CONFIG_PPC_8xx_PERF_EVENT +#if defined(CONFIG_PPC_8xx) && defined(CONFIG_PERF_EVENTS) mtspr SPRN_NRI, r0 #endif mtspr SPRN_SRR1,r9 @@ -978,7 +978,7 @@ END_FTR_SECTION_IFSET(CPU_FTR_NEED_PAIRED_STWCX) .globl exc_exit_restart exc_exit_restart: lwz r12,_NIP(r1) -#ifdef CONFIG_PPC_8xx_PERF_EVENT +#if defined(CONFIG_PPC_8xx) && defined(CONFIG_PERF_EVENTS) mtspr SPRN_NRI, r0 #endif mtspr SPRN_SRR0,r12 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 diff --git a/arch/powerpc/perf/8xx-pmu.c b/arch/powerpc/perf/8xx-pmu.c index 3c39f05f0af3..6c0020d1c561 100644 --- a/arch/powerpc/perf/8xx-pmu.c +++ b/arch/powerpc/perf/8xx-pmu.c @@ -18,6 +18,7 @@ #include #include #include +#include #define PERF_8xx_ID_CPU_CYCLES 1 #define PERF_8xx_ID_HW_INSTRUCTIONS 2 @@ -30,8 +31,13 @@ extern unsigned long itlb_miss_counter, dtlb_miss_counter; extern atomic_t instruction_counter; +extern unsigned int itlb_miss_perf, dtlb_miss_perf; +extern unsigned int itlb_miss_exit_1, itlb_miss_exit_2; +extern unsigned int dtlb_miss_exit_1, dtlb_miss_exit_2, dtlb_miss_exit_3; static atomic_t insn_ctr_ref; +static atomic_t itlb_miss_ref; +static atomic_t dtlb_miss_ref; static s64 get_insn_ctr(void) { @@ -96,9 +102,24 @@ static int mpc8xx_pmu_add(struct perf_event *event, int flags) val = get_insn_ctr(); break; case PERF_8xx_ID_ITLB_LOAD_MISS: + if (atomic_inc_return(&itlb_miss_ref) == 1) { + unsigned long target = (unsigned long)&itlb_miss_perf; + + patch_branch(&itlb_miss_exit_1, target, 0); +#ifndef CONFIG_PIN_TLB_TEXT + patch_branch(&itlb_miss_exit_2, target, 0); +#endif + } val = itlb_miss_counter; break; case PERF_8xx_ID_DTLB_LOAD_MISS: + if (atomic_inc_return(&dtlb_miss_ref) == 1) { + unsigned long target = (unsigned long)&dtlb_miss_perf; + + patch_branch(&dtlb_miss_exit_1, target, 0); + patch_branch(&dtlb_miss_exit_2, target, 0); + patch_branch(&dtlb_miss_exit_3, target, 0); + } val = dtlb_miss_counter; break; } @@ -143,13 +164,36 @@ static void mpc8xx_pmu_read(struct perf_event *event) static void mpc8xx_pmu_del(struct perf_event *event, int flags) { + /* mfspr r10, SPRN_SPRG_SCRATCH0 */ + unsigned int insn = PPC_INST_MFSPR | __PPC_RS(R10) | + __PPC_SPR(SPRN_SPRG_SCRATCH0); + mpc8xx_pmu_read(event); - if (event_type(event) != PERF_8xx_ID_HW_INSTRUCTIONS) - return; /* If it was the last user, stop counting to avoid useles overhead */ - if (atomic_dec_return(&insn_ctr_ref) == 0) - mtspr(SPRN_ICTRL, 7); + switch (event_type(event)) { + case PERF_8xx_ID_CPU_CYCLES: + break; + case PERF_8xx_ID_HW_INSTRUCTIONS: + if (atomic_dec_return(&insn_ctr_ref) == 0) + mtspr(SPRN_ICTRL, 7); + break; + case PERF_8xx_ID_ITLB_LOAD_MISS: + if (atomic_dec_return(&itlb_miss_ref) == 0) { + patch_instruction(&itlb_miss_exit_1, insn); +#ifndef CONFIG_PIN_TLB_TEXT + patch_instruction(&itlb_miss_exit_2, insn); +#endif + } + break; + case PERF_8xx_ID_DTLB_LOAD_MISS: + if (atomic_dec_return(&dtlb_miss_ref) == 0) { + patch_instruction(&dtlb_miss_exit_1, insn); + patch_instruction(&dtlb_miss_exit_2, insn); + patch_instruction(&dtlb_miss_exit_3, insn); + } + break; + } } static struct pmu mpc8xx_pmu = { diff --git a/arch/powerpc/perf/Makefile b/arch/powerpc/perf/Makefile index 225c9c86d7c0..57ebc655d2ac 100644 --- a/arch/powerpc/perf/Makefile +++ b/arch/powerpc/perf/Makefile @@ -15,7 +15,7 @@ obj-$(CONFIG_FSL_EMB_PERF_EVENT_E500) += e500-pmu.o e6500-pmu.o obj-$(CONFIG_HV_PERF_CTRS) += hv-24x7.o hv-gpci.o hv-common.o -obj-$(CONFIG_PPC_8xx_PERF_EVENT) += 8xx-pmu.o +obj-$(CONFIG_PPC_8xx) += 8xx-pmu.o obj-$(CONFIG_PPC64) += $(obj64-y) obj-$(CONFIG_PPC32) += $(obj32-y) diff --git a/arch/powerpc/platforms/Kconfig.cputype b/arch/powerpc/platforms/Kconfig.cputype index c838581f81f1..a429d859f15d 100644 --- a/arch/powerpc/platforms/Kconfig.cputype +++ b/arch/powerpc/platforms/Kconfig.cputype @@ -167,13 +167,6 @@ config PPC_FPU bool default y if PPC64 -config PPC_8xx_PERF_EVENT - bool "PPC 8xx perf events" - depends on PPC_8xx && PERF_EVENTS - help - This is Performance Events support for PPC 8xx. The 8xx doesn't - have a PMU but some events are emulated using 8xx features. - config FSL_EMB_PERFMON bool "Freescale Embedded Perfmon" depends on E500 || PPC_83xx