From 82622284dd2f8791f9759f3cef601520a8bc63b2 Mon Sep 17 00:00:00 2001 From: David Daney Date: Wed, 14 Oct 2009 12:16:56 -0700 Subject: [PATCH] MIPS: Put PGD in C0_CONTEXT for 64-bit R2 processors. Processors that support the mips64r2 ISA can in four instructions convert a shifted PGD pointer stored in the upper bits of c0_context into a usable pointer. By doing this we save a memory load and associated potential cache miss in the TLB exception handlers. Since the upper bits of c0_context were holding the CPU number, we move this to the upper bits of c0_xcontext which doesn't have enough bits to hold the PGD pointer, but has plenty for the CPU number. Signed-off-by: David Daney Signed-off-by: Ralf Baechle --- arch/mips/Kconfig | 3 +++ arch/mips/include/asm/mmu_context.h | 29 ++++++++++++++++++++++++++++- arch/mips/include/asm/stackframe.h | 20 ++++++++++---------- arch/mips/mm/init.c | 2 ++ arch/mips/mm/tlbex.c | 28 +++++++++++++++++++++++++--- 5 files changed, 68 insertions(+), 14 deletions(-) diff --git a/arch/mips/Kconfig b/arch/mips/Kconfig index f6f3b99..20b223b 100644 --- a/arch/mips/Kconfig +++ b/arch/mips/Kconfig @@ -1427,6 +1427,9 @@ config CPU_SUPPORTS_64BIT_KERNEL bool config CPU_SUPPORTS_HUGEPAGES bool +config MIPS_PGD_C0_CONTEXT + bool + default y if 64BIT && CPU_MIPSR2 # # Set to y for ptrace access to watch registers. diff --git a/arch/mips/include/asm/mmu_context.h b/arch/mips/include/asm/mmu_context.h index 6083db5..145bb81 100644 --- a/arch/mips/include/asm/mmu_context.h +++ b/arch/mips/include/asm/mmu_context.h @@ -24,6 +24,33 @@ #endif /* SMTC */ #include +#ifdef CONFIG_MIPS_PGD_C0_CONTEXT + +#define TLBMISS_HANDLER_SETUP_PGD(pgd) \ + tlbmiss_handler_setup_pgd((unsigned long)(pgd)) + +static inline void tlbmiss_handler_setup_pgd(unsigned long pgd) +{ + /* Check for swapper_pg_dir and convert to physical address. */ + if ((pgd & CKSEG3) == CKSEG0) + pgd = CPHYSADDR(pgd); + write_c0_context(pgd << 11); +} + +#define TLBMISS_HANDLER_SETUP() \ + do { \ + TLBMISS_HANDLER_SETUP_PGD(swapper_pg_dir); \ + write_c0_xcontext((unsigned long) smp_processor_id() << 51); \ + } while (0) + + +static inline unsigned long get_current_pgd(void) +{ + return PHYS_TO_XKSEG_CACHED((read_c0_context() >> 11) & ~0xfffUL); +} + +#else /* CONFIG_MIPS_PGD_C0_CONTEXT: using pgd_current*/ + /* * For the fast tlb miss handlers, we keep a per cpu array of pointers * to the current pgd for each processor. Also, the proc. id is stuffed @@ -46,7 +73,7 @@ extern unsigned long pgd_current[]; back_to_back_c0_hazard(); \ TLBMISS_HANDLER_SETUP_PGD(swapper_pg_dir) #endif - +#endif /* CONFIG_MIPS_PGD_C0_CONTEXT*/ #if defined(CONFIG_CPU_R3000) || defined(CONFIG_CPU_TX39XX) #define ASID_INC 0x40 diff --git a/arch/mips/include/asm/stackframe.h b/arch/mips/include/asm/stackframe.h index dd7e220..3b6da33 100644 --- a/arch/mips/include/asm/stackframe.h +++ b/arch/mips/include/asm/stackframe.h @@ -87,15 +87,19 @@ #ifdef CONFIG_SMP #ifdef CONFIG_MIPS_MT_SMTC #define PTEBASE_SHIFT 19 /* TCBIND */ +#define CPU_ID_REG CP0_TCBIND +#define CPU_ID_MFC0 mfc0 +#elif defined(CONFIG_MIPS_PGD_C0_CONTEXT) +#define PTEBASE_SHIFT 48 /* XCONTEXT */ +#define CPU_ID_REG CP0_XCONTEXT +#define CPU_ID_MFC0 MFC0 #else #define PTEBASE_SHIFT 23 /* CONTEXT */ +#define CPU_ID_REG CP0_CONTEXT +#define CPU_ID_MFC0 MFC0 #endif .macro get_saved_sp /* SMP variation */ -#ifdef CONFIG_MIPS_MT_SMTC - mfc0 k0, CP0_TCBIND -#else - MFC0 k0, CP0_CONTEXT -#endif + CPU_ID_MFC0 k0, CPU_ID_REG #if defined(CONFIG_32BIT) || defined(KBUILD_64BIT_SYM32) lui k1, %hi(kernelsp) #else @@ -111,11 +115,7 @@ .endm .macro set_saved_sp stackp temp temp2 -#ifdef CONFIG_MIPS_MT_SMTC - mfc0 \temp, CP0_TCBIND -#else - MFC0 \temp, CP0_CONTEXT -#endif + CPU_ID_MFC0 \temp, CPU_ID_REG LONG_SRL \temp, PTEBASE_SHIFT LONG_S \stackp, kernelsp(\temp) .endm diff --git a/arch/mips/mm/init.c b/arch/mips/mm/init.c index 8d1f4f3..9e8d003 100644 --- a/arch/mips/mm/init.c +++ b/arch/mips/mm/init.c @@ -462,7 +462,9 @@ void __init_refok free_initmem(void) __pa_symbol(&__init_end)); } +#ifndef CONFIG_MIPS_PGD_C0_CONTEXT unsigned long pgd_current[NR_CPUS]; +#endif /* * On 64-bit we've got three-level pagetables with a slightly * different layout ... diff --git a/arch/mips/mm/tlbex.c b/arch/mips/mm/tlbex.c index bb1719a..3d0baa4 100644 --- a/arch/mips/mm/tlbex.c +++ b/arch/mips/mm/tlbex.c @@ -160,6 +160,12 @@ static u32 tlb_handler[128] __cpuinitdata; static struct uasm_label labels[128] __cpuinitdata; static struct uasm_reloc relocs[128] __cpuinitdata; +#ifndef CONFIG_MIPS_PGD_C0_CONTEXT +/* + * CONFIG_MIPS_PGD_C0_CONTEXT implies 64 bit and lack of pgd_current, + * we cannot do r3000 under these circumstances. + */ + /* * The R3000 TLB handler is simple. */ @@ -199,6 +205,7 @@ static void __cpuinit build_r3000_tlb_refill_handler(void) dump_handler((u32 *)ebase, 32); } +#endif /* CONFIG_MIPS_PGD_C0_CONTEXT */ /* * The R4000 TLB handler is much more complicated. We have two @@ -497,8 +504,9 @@ static void __cpuinit build_get_pmde64(u32 **p, struct uasm_label **l, struct uasm_reloc **r, unsigned int tmp, unsigned int ptr) { +#ifndef CONFIG_MIPS_PGD_C0_CONTEXT long pgdc = (long)pgd_current; - +#endif /* * The vmalloc handling is not in the hotpath. */ @@ -506,7 +514,15 @@ build_get_pmde64(u32 **p, struct uasm_label **l, struct uasm_reloc **r, uasm_il_bltz(p, r, tmp, label_vmalloc); /* No uasm_i_nop needed here, since the next insn doesn't touch TMP. */ -#ifdef CONFIG_SMP +#ifdef CONFIG_MIPS_PGD_C0_CONTEXT + /* + * &pgd << 11 stored in CONTEXT [23..63]. + */ + UASM_i_MFC0(p, ptr, C0_CONTEXT); + uasm_i_dins(p, ptr, 0, 0, 23); /* Clear lower 23 bits of context. */ + uasm_i_ori(p, ptr, ptr, 0x540); /* 1 0 1 0 1 << 6 xkphys cached */ + uasm_i_drotr(p, ptr, ptr, 11); +#elif defined(CONFIG_SMP) # ifdef CONFIG_MIPS_MT_SMTC /* * SMTC uses TCBind value as "CPU" index @@ -520,7 +536,7 @@ build_get_pmde64(u32 **p, struct uasm_label **l, struct uasm_reloc **r, */ uasm_i_dmfc0(p, ptr, C0_CONTEXT); uasm_i_dsrl(p, ptr, ptr, 23); -#endif +# endif UASM_i_LA_mostly(p, tmp, pgdc); uasm_i_daddu(p, ptr, ptr, tmp); uasm_i_dmfc0(p, tmp, C0_BADVADDR); @@ -1033,6 +1049,7 @@ build_pte_modifiable(u32 **p, struct uasm_reloc **r, iPTE_LW(p, pte, ptr); } +#ifndef CONFIG_MIPS_PGD_C0_CONTEXT /* * R3000 style TLB load/store/modify handlers. */ @@ -1184,6 +1201,7 @@ static void __cpuinit build_r3000_tlb_modify_handler(void) dump_handler(handle_tlbm, ARRAY_SIZE(handle_tlbm)); } +#endif /* CONFIG_MIPS_PGD_C0_CONTEXT */ /* * R4000 style TLB load/store/modify handlers. @@ -1400,6 +1418,7 @@ void __cpuinit build_tlb_refill_handler(void) case CPU_TX3912: case CPU_TX3922: case CPU_TX3927: +#ifndef CONFIG_MIPS_PGD_C0_CONTEXT build_r3000_tlb_refill_handler(); if (!run_once) { build_r3000_tlb_load_handler(); @@ -1407,6 +1426,9 @@ void __cpuinit build_tlb_refill_handler(void) build_r3000_tlb_modify_handler(); run_once++; } +#else + panic("No R3000 TLB refill handler"); +#endif break; case CPU_R6000: -- 2.7.4