[PATCH] powerpc/book3e-64: use a separate TLB handler when linear map is bolted
From: Scott Wood <hidden>
Date: 2011-06-03 22:12:43
On MMUs such as FSL where we can guarantee the entire linear mapping is bolted, we don't need to worry about linear TLB misses. If on top of that we do a full table walk, we get rid of all recursive TLB faults, and can dispense with some state saving. This gains a few percent on TLB-miss-heavy workloads, and around 50% on a benchmark that had a high rate of virtual page table faults under the normal handler. While touching the EX_TLB layout, remove EX_TLB_MMUCR0, EX_TLB_SRR0, and EX_TLB_SRR1 as they're not used. Signed-off-by: Scott Wood <redacted> --- This turned out to be a little faster than the virtual pmd approach on the sort benchmark as well as lmbench's lat_mem_rd with page stride. It's slightly slower than virtual pmd (around 1%), but still faster than current code, on linear tests such as lmbench's bw_mem cp. arch/powerpc/include/asm/exception-64e.h | 47 ++++--- arch/powerpc/include/asm/mmu_context.h | 2 + arch/powerpc/mm/tlb_low_64e.S | 206 ++++++++++++++++++++++++++++++ arch/powerpc/mm/tlb_nohash.c | 30 +++- 4 files changed, 259 insertions(+), 26 deletions(-)
diff --git a/arch/powerpc/include/asm/exception-64e.h b/arch/powerpc/include/asm/exception-64e.h
index 6d53f31..1e001f0 100644
--- a/arch/powerpc/include/asm/exception-64e.h
+++ b/arch/powerpc/include/asm/exception-64e.h@@ -50,28 +50,26 @@ /* The TLB miss exception uses different slots */ -#define EX_TLB_R10 ( 0 * 8) -#define EX_TLB_R11 ( 1 * 8) -#define EX_TLB_R12 ( 2 * 8) +#define EX_TLB_PGD ( 0 * 8) +#define EX_TLB_R10 ( 1 * 8) +#define EX_TLB_R11 ( 2 * 8) #define EX_TLB_R13 ( 3 * 8) #define EX_TLB_R14 ( 4 * 8) #define EX_TLB_R15 ( 5 * 8) #define EX_TLB_R16 ( 6 * 8) #define EX_TLB_CR ( 7 * 8) -#define EX_TLB_DEAR ( 8 * 8) /* Level 0 and 2 only */ -#define EX_TLB_ESR ( 9 * 8) /* Level 0 and 2 only */ -#define EX_TLB_SRR0 (10 * 8) -#define EX_TLB_SRR1 (11 * 8) -#define EX_TLB_MMUCR0 (12 * 8) /* Level 0 */ -#define EX_TLB_MAS1 (12 * 8) /* Level 0 */ -#define EX_TLB_MAS2 (13 * 8) /* Level 0 */ +#define EX_TLB_R12 ( 8 * 8) +#define EX_TLB_DEAR ( 9 * 8) /* Level 0 and 2 only */ +#define EX_TLB_ESR (10 * 8) /* Level 0 and 2 only */ +#define EX_TLB_SRR0 (11 * 8) +#define EX_TLB_SRR1 (12 * 8) #ifdef CONFIG_BOOK3E_MMU_TLB_STATS -#define EX_TLB_R8 (14 * 8) -#define EX_TLB_R9 (15 * 8) -#define EX_TLB_LR (16 * 8) -#define EX_TLB_SIZE (17 * 8) +#define EX_TLB_R8 (13 * 8) +#define EX_TLB_R9 (14 * 8) +#define EX_TLB_LR (15 * 8) +#define EX_TLB_SIZE (16 * 8) #else -#define EX_TLB_SIZE (14 * 8) +#define EX_TLB_SIZE (13 * 8) #endif #define START_EXCEPTION(label) \
@@ -168,6 +166,16 @@ exc_##label##_book3e: ld r9,EX_TLB_R9(r12); \ ld r8,EX_TLB_R8(r12); \ mtlr r16; +#define TLB_MISS_PROLOG_STATS_BOLTED \ + mflr r10; \ + std r8,PACA_EXTLB+EX_TLB_R8(r13); \ + std r9,PACA_EXTLB+EX_TLB_R9(r13); \ + std r10,PACA_EXTLB+EX_TLB_LR(r13); +#define TLB_MISS_RESTORE_STATS_BOLTED \ + ld r16,PACA_EXTLB+EX_TLB_LR(r13); \ + ld r9,PACA_EXTLB+EX_TLB_R9(r13); \ + ld r8,PACA_EXTLB+EX_TLB_R8(r13); \ + mtlr r16; #define TLB_MISS_STATS_D(name) \ addi r9,r13,MMSTAT_DSTATS+name; \ bl .tlb_stat_inc;
@@ -183,17 +191,20 @@ exc_##label##_book3e: 61: addi r9,r13,MMSTAT_ISTATS+name; \ 62: bl .tlb_stat_inc; #define TLB_MISS_STATS_SAVE_INFO \ - std r14,EX_TLB_ESR(r12); /* save ESR */ \ - - + std r14,EX_TLB_ESR(r12); /* save ESR */ +#define TLB_MISS_STATS_SAVE_INFO_BOLTED \ + std r14,PACA_EXTLB+EX_TLB_ESR(r13); /* save ESR */ #else #define TLB_MISS_PROLOG_STATS #define TLB_MISS_RESTORE_STATS +#define TLB_MISS_PROLOG_STATS_BOLTED +#define TLB_MISS_RESTORE_STATS_BOLTED #define TLB_MISS_STATS_D(name) #define TLB_MISS_STATS_I(name) #define TLB_MISS_STATS_X(name) #define TLB_MISS_STATS_Y(name) #define TLB_MISS_STATS_SAVE_INFO +#define TLB_MISS_STATS_SAVE_INFO_BOLTED #endif #define SET_IVOR(vector_number, vector_offset) \
diff --git a/arch/powerpc/include/asm/mmu_context.h b/arch/powerpc/include/asm/mmu_context.h
index a73668a..9d9e444 100644
--- a/arch/powerpc/include/asm/mmu_context.h
+++ b/arch/powerpc/include/asm/mmu_context.h@@ -54,6 +54,7 @@ static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next, /* 64-bit Book3E keeps track of current PGD in the PACA */ #ifdef CONFIG_PPC_BOOK3E_64 get_paca()->pgd = next->pgd; + get_paca()->extlb[0][EX_TLB_PGD / 8] = (unsigned long)next->pgd; #endif /* Nothing else to do if we aren't actually switching */ if (prev == next)
@@ -110,6 +111,7 @@ static inline void enter_lazy_tlb(struct mm_struct *mm, /* 64-bit Book3E keeps track of current PGD in the PACA */ #ifdef CONFIG_PPC_BOOK3E_64 get_paca()->pgd = NULL; + get_paca()->extlb[0][EX_TLB_PGD / 8] = 0; #endif }
diff --git a/arch/powerpc/mm/tlb_low_64e.S b/arch/powerpc/mm/tlb_low_64e.S
index af08922..0f4ab86 100644
--- a/arch/powerpc/mm/tlb_low_64e.S
+++ b/arch/powerpc/mm/tlb_low_64e.S@@ -30,6 +30,212 @@ #define VPTE_PGD_SHIFT (VPTE_PUD_SHIFT + PUD_INDEX_SIZE) #define VPTE_INDEX_SIZE (VPTE_PGD_SHIFT + PGD_INDEX_SIZE) +/********************************************************************** + * * + * TLB miss handling for Book3E with a bolted linear mapping * + * No virtual page table, no nested TLB misses * + * * + **********************************************************************/ + +.macro tlb_prolog_bolted addr + mtspr SPRN_SPRG_TLB_SCRATCH,r13 + mfspr r13,SPRN_SPRG_PACA + std r10,PACA_EXTLB+EX_TLB_R10(r13) + mfcr r10 + std r11,PACA_EXTLB+EX_TLB_R11(r13) + mfspr r11,SPRN_SPRG_TLB_SCRATCH + std r16,PACA_EXTLB+EX_TLB_R16(r13) + mfspr r16,\addr /* get faulting address */ + std r14,PACA_EXTLB+EX_TLB_R14(r13) + ld r14,PACA_EXTLB+EX_TLB_PGD(r13) + std r15,PACA_EXTLB+EX_TLB_R15(r13) + std r10,PACA_EXTLB+EX_TLB_CR(r13) + std r11,PACA_EXTLB+EX_TLB_R13(r13) + TLB_MISS_PROLOG_STATS_BOLTED +.endm + +.macro tlb_epilog_bolted + ld r14,PACA_EXTLB+EX_TLB_CR(r13) + ld r10,PACA_EXTLB+EX_TLB_R10(r13) + ld r11,PACA_EXTLB+EX_TLB_R11(r13) + mtcr r14 + ld r14,PACA_EXTLB+EX_TLB_R14(r13) + ld r15,PACA_EXTLB+EX_TLB_R15(r13) + TLB_MISS_RESTORE_STATS_BOLTED + ld r16,PACA_EXTLB+EX_TLB_R16(r13) + ld r13,PACA_EXTLB+EX_TLB_R13(r13) +.endm + +/* Data TLB miss */ + START_EXCEPTION(data_tlb_miss_bolted) + tlb_prolog_bolted SPRN_DEAR + + /* We need _PAGE_PRESENT and _PAGE_ACCESSED set */ + + /* We do the user/kernel test for the PID here along with the RW test + */ + /* We pre-test some combination of permissions to avoid double + * faults: + * + * We move the ESR:ST bit into the position of _PAGE_BAP_SW in the PTE + * ESR_ST is 0x00800000 + * _PAGE_BAP_SW is 0x00000010 + * So the shift is >> 19. This tests for supervisor writeability. + * If the page happens to be supervisor writeable and not user + * writeable, we will take a new fault later, but that should be + * a rare enough case. + * + * We also move ESR_ST in _PAGE_DIRTY position + * _PAGE_DIRTY is 0x00001000 so the shift is >> 11 + * + * MAS1 is preset for all we need except for TID that needs to + * be cleared for kernel translations + */ + + mfspr r11,SPRN_ESR + + srdi r15,r16,60 /* get region */ + rldicl. r10,r16,64-PGTABLE_EADDR_SIZE,PGTABLE_EADDR_SIZE+4 + bne- dtlb_miss_fault_bolted + + rlwinm r10,r11,32-19,27,27 + rlwimi r10,r11,32-16,19,19 + cmpwi r15,0 + ori r10,r10,_PAGE_PRESENT + oris r11,r10,_PAGE_ACCESSED@h + + TLB_MISS_STATS_SAVE_INFO_BOLTED + bne tlb_miss_kernel_bolted + +tlb_miss_common_bolted: +/* + * This is the guts of the TLB miss handler for bolted-linear. + * We are entered with: + * + * r16 = faulting address + * r15 = crap (free to use) + * r14 = page table base + * r13 = PACA + * r11 = PTE permission mask + * r10 = crap (free to use) + */ + rldicl r15,r16,64-PGDIR_SHIFT+3,64-PGD_INDEX_SIZE-3 + cmpldi cr0,r14,0 + clrrdi r15,r15,3 + beq tlb_miss_fault_bolted + +BEGIN_MMU_FTR_SECTION + /* Set the TLB reservation and search for existing entry. Then load + * the entry. + */ + PPC_TLBSRX_DOT(0,r16) + ldx r14,r14,r15 + beq normal_tlb_miss_done +MMU_FTR_SECTION_ELSE + ldx r14,r14,r15 +ALT_MMU_FTR_SECTION_END_IFSET(MMU_FTR_USE_TLBRSRV) + + rldicl r15,r16,64-PUD_SHIFT+3,64-PUD_INDEX_SIZE-3 + clrrdi r15,r15,3 + + cmpldi cr0,r14,0 + beq tlb_miss_fault_bolted + + ldx r14,r14,r15 + + rldicl r15,r16,64-PMD_SHIFT+3,64-PMD_INDEX_SIZE-3 + clrrdi r15,r15,3 + + cmpldi cr0,r14,0 + beq tlb_miss_fault_bolted + + ldx r14,r14,r15 + + rldicl r15,r16,64-PAGE_SHIFT+3,64-PTE_INDEX_SIZE-3 + clrrdi r15,r15,3 + + cmpldi cr0,r14,0 + beq tlb_miss_fault_bolted + + ldx r14,r14,r15 + + /* Check if required permissions are met */ + andc. r15,r11,r14 + rldicr r15,r14,64-(PTE_RPN_SHIFT-PAGE_SHIFT),63-PAGE_SHIFT + bne- tlb_miss_fault_bolted + + /* Now we build the MAS: + * + * MAS 0 : Fully setup with defaults in MAS4 and TLBnCFG + * MAS 1 : Almost fully setup + * - PID already updated by caller if necessary + * - TSIZE need change if !base page size, not + * yet implemented for now + * MAS 2 : Defaults not useful, need to be redone + * MAS 3+7 : Needs to be done + */ + clrrdi r11,r16,12 /* Clear low crap in EA */ + clrldi r15,r15,12 /* Clear crap at the top */ + rlwimi r11,r14,32-19,27,31 /* Insert WIMGE */ + rlwimi r15,r14,32-8,22,25 /* Move in U bits */ + mtspr SPRN_MAS2,r11 + andi. r11,r14,_PAGE_DIRTY + rlwimi r15,r14,32-2,26,31 /* Move in BAP bits */ + + /* Mask out SW and UW if !DIRTY (XXX optimize this !) */ + bne 1f + li r11,MAS3_SW|MAS3_UW + andc r15,r15,r11 +1: + mtspr SPRN_MAS7_MAS3,r15 + tlbwe + + TLB_MISS_STATS_X(MMSTAT_TLB_MISS_NORM_OK) + tlb_epilog_bolted + rfi + +itlb_miss_kernel_bolted: + li r11,_PAGE_PRESENT|_PAGE_BAP_SX /* Base perm */ + oris r11,r11,_PAGE_ACCESSED@h +tlb_miss_kernel_bolted: + mfspr r10,SPRN_MAS1 + ld r14,PACA_KERNELPGD(r13) + cmpldi cr0,r15,8 /* Check for vmalloc region */ + rlwinm r10,r10,0,16,1 /* Clear TID */ + mtspr SPRN_MAS1,r10 + beq+ tlb_miss_common_bolted + +tlb_miss_fault_bolted: + /* We need to check if it was an instruction miss */ + andi. r10,r11,_PAGE_EXEC|_PAGE_BAP_SX + bne itlb_miss_fault_bolted +dtlb_miss_fault_bolted: + TLB_MISS_STATS_D(MMSTAT_TLB_MISS_NORM_FAULT) + tlb_epilog_bolted + b exc_data_storage_book3e +itlb_miss_fault_bolted: + TLB_MISS_STATS_I(MMSTAT_TLB_MISS_NORM_FAULT) + tlb_epilog_bolted + b exc_instruction_storage_book3e + +/* Instruction TLB miss */ + START_EXCEPTION(instruction_tlb_miss_bolted) + tlb_prolog_bolted SPRN_SRR0 + + rldicl. r10,r16,64-PGTABLE_EADDR_SIZE,PGTABLE_EADDR_SIZE+4 + srdi r15,r16,60 /* get region */ + TLB_MISS_STATS_SAVE_INFO_BOLTED + bne- itlb_miss_fault_bolted + + li r11,_PAGE_PRESENT|_PAGE_EXEC /* Base perm */ + + /* We do the user/kernel test for the PID here along with the RW test + */ + + cmpldi cr0,r15,0 /* Check for user region */ + oris r11,r11,_PAGE_ACCESSED@h + beq tlb_miss_common_bolted + b itlb_miss_kernel_bolted /********************************************************************** * *
diff --git a/arch/powerpc/mm/tlb_nohash.c b/arch/powerpc/mm/tlb_nohash.c
index 0bdad3a..2ba051e 100644
--- a/arch/powerpc/mm/tlb_nohash.c
+++ b/arch/powerpc/mm/tlb_nohash.c@@ -443,14 +443,27 @@ static void setup_page_sizes(void) } } -static void setup_mmu_htw(void) +static void __patch_exception(int exc, unsigned long addr) { extern unsigned int interrupt_base_book3e; - extern unsigned int exc_data_tlb_miss_htw_book3e; - extern unsigned int exc_instruction_tlb_miss_htw_book3e; + unsigned int *ibase = &interrupt_base_book3e; + + /* Our exceptions vectors start with a NOP and -then- a branch + * to deal with single stepping from userspace which stops on + * the second instruction. Thus we need to patch the second + * instruction of the exception, not the first one + */ + + patch_branch(ibase + (exc / 4) + 1, addr, 0); +} - unsigned int *ibase = &interrupt_base_book3e; +#define patch_exception(exc, name) do { \ + extern unsigned int name; \ + __patch_exception((exc), (unsigned long)&name); \ +} while (0) +static void setup_mmu_htw(void) +{ /* Check if HW tablewalk is present, and if yes, enable it by: * * - patching the TLB miss handlers to branch to the
@@ -467,10 +480,8 @@ static void setup_mmu_htw(void) * the second instruction. Thus we need to patch the second * instruction of the exception, not the first one */ - patch_branch(ibase + (0x1c0 / 4) + 1, - (unsigned long)&exc_data_tlb_miss_htw_book3e, 0); - patch_branch(ibase + (0x1e0 / 4) + 1, - (unsigned long)&exc_instruction_tlb_miss_htw_book3e, 0); + patch_exception(0x1c0, exc_data_tlb_miss_htw_book3e); + patch_exception(0x1e0, exc_instruction_tlb_miss_htw_book3e); book3e_htw_enabled = 1; } pr_info("MMU: Book3E Page Tables %s\n",
@@ -549,6 +560,9 @@ static void __early_init_mmu(int boot_cpu) /* limit memory so we dont have linear faults */ memblock_enforce_memory_limit(linear_map_top); memblock_analyze(); + + patch_exception(0x1c0, exc_data_tlb_miss_bolted_book3e); + patch_exception(0x1e0, exc_instruction_tlb_miss_bolted_book3e); } #endif
--
1.7.4.1