From 63eca94ca206e342bad4a06a86d8e7eda3053a4e Mon Sep 17 00:00:00 2001 From: Vineet Gupta Date: Fri, 23 Aug 2013 19:16:34 +0530 Subject: [PATCH] ARC: [SMP] ASID allocation -Track a Per CPU ASID counter -mm-per-cpu ASID (multiple threads, or mm migrated around) Signed-off-by: Vineet Gupta --- arch/arc/include/asm/mmu.h | 2 +- arch/arc/include/asm/mmu_context.h | 44 +++++++++++++++++++----------- arch/arc/mm/tlb.c | 14 ++++++---- 3 files changed, 37 insertions(+), 23 deletions(-) diff --git a/arch/arc/include/asm/mmu.h b/arch/arc/include/asm/mmu.h index c2663b32866b..8c84ae98c337 100644 --- a/arch/arc/include/asm/mmu.h +++ b/arch/arc/include/asm/mmu.h @@ -48,7 +48,7 @@ #ifndef __ASSEMBLY__ typedef struct { - unsigned long asid; /* 8 bit MMU PID + Generation cycle */ + unsigned long asid[NR_CPUS]; /* 8 bit MMU PID + Generation cycle */ } mm_context_t; #ifdef CONFIG_ARC_DBG_TLB_PARANOIA diff --git a/arch/arc/include/asm/mmu_context.h b/arch/arc/include/asm/mmu_context.h index 43a1b51bb8cc..45f06f566b02 100644 --- a/arch/arc/include/asm/mmu_context.h +++ b/arch/arc/include/asm/mmu_context.h @@ -30,13 +30,13 @@ * "Fast Context Switch" i.e. no TLB flush on ctxt-switch * * Linux assigns each task a unique ASID. A simple round-robin allocation - * of H/w ASID is done using software tracker @asid_cache. + * of H/w ASID is done using software tracker @asid_cpu. * When it reaches max 255, the allocation cycle starts afresh by flushing * the entire TLB and wrapping ASID back to zero. * * A new allocation cycle, post rollover, could potentially reassign an ASID * to a different task. Thus the rule is to refresh the ASID in a new cycle. - * The 32 bit @asid_cache (and mm->asid) have 8 bits MMU PID and rest 24 bits + * The 32 bit @asid_cpu (and mm->asid) have 8 bits MMU PID and rest 24 bits * serve as cycle/generation indicator and natural 32 bit unsigned math * automagically increments the generation when lower 8 bits rollover. */ @@ -47,9 +47,11 @@ #define MM_CTXT_FIRST_CYCLE (MM_CTXT_ASID_MASK + 1) #define MM_CTXT_NO_ASID 0UL -#define hw_pid(mm) (mm->context.asid & MM_CTXT_ASID_MASK) +#define asid_mm(mm, cpu) mm->context.asid[cpu] +#define hw_pid(mm, cpu) (asid_mm(mm, cpu) & MM_CTXT_ASID_MASK) -extern unsigned int asid_cache; +DECLARE_PER_CPU(unsigned int, asid_cache); +#define asid_cpu(cpu) per_cpu(asid_cache, cpu) /* * Get a new ASID if task doesn't have a valid one (unalloc or from prev cycle) @@ -57,6 +59,7 @@ extern unsigned int asid_cache; */ static inline void get_new_mmu_context(struct mm_struct *mm) { + const unsigned int cpu = smp_processor_id(); unsigned long flags; local_irq_save(flags); @@ -71,11 +74,11 @@ static inline void get_new_mmu_context(struct mm_struct *mm) * first need to destroy the context, setting it to invalid * value. */ - if (!((mm->context.asid ^ asid_cache) & MM_CTXT_CYCLE_MASK)) + if (!((asid_mm(mm, cpu) ^ asid_cpu(cpu)) & MM_CTXT_CYCLE_MASK)) goto set_hw; /* move to new ASID and handle rollover */ - if (unlikely(!(++asid_cache & MM_CTXT_ASID_MASK))) { + if (unlikely(!(++asid_cpu(cpu) & MM_CTXT_ASID_MASK))) { flush_tlb_all(); @@ -84,15 +87,15 @@ static inline void get_new_mmu_context(struct mm_struct *mm) * If the container itself wrapped around, set it to a non zero * "generation" to distinguish from no context */ - if (!asid_cache) - asid_cache = MM_CTXT_FIRST_CYCLE; + if (!asid_cpu(cpu)) + asid_cpu(cpu) = MM_CTXT_FIRST_CYCLE; } /* Assign new ASID to tsk */ - mm->context.asid = asid_cache; + asid_mm(mm, cpu) = asid_cpu(cpu); set_hw: - write_aux_reg(ARC_REG_PID, hw_pid(mm) | MMU_ENABLE); + write_aux_reg(ARC_REG_PID, hw_pid(mm, cpu) | MMU_ENABLE); local_irq_restore(flags); } @@ -104,10 +107,24 @@ set_hw: static inline int init_new_context(struct task_struct *tsk, struct mm_struct *mm) { - mm->context.asid = MM_CTXT_NO_ASID; + int i; + + for_each_possible_cpu(i) + asid_mm(mm, i) = MM_CTXT_NO_ASID; + return 0; } +static inline void destroy_context(struct mm_struct *mm) +{ + unsigned long flags; + + /* Needed to elide CONFIG_DEBUG_PREEMPT warning */ + local_irq_save(flags); + asid_mm(mm, smp_processor_id()) = MM_CTXT_NO_ASID; + local_irq_restore(flags); +} + /* Prepare the MMU for task: setup PID reg with allocated ASID If task doesn't have an ASID (never alloc or stolen, get a new ASID) */ @@ -131,11 +148,6 @@ static inline void switch_mm(struct mm_struct *prev, struct mm_struct *next, */ #define activate_mm(prev, next) switch_mm(prev, next, NULL) -static inline void destroy_context(struct mm_struct *mm) -{ - mm->context.asid = MM_CTXT_NO_ASID; -} - /* it seemed that deactivate_mm( ) is a reasonable place to do book-keeping * for retiring-mm. However destroy_context( ) still needs to do that because * between mm_release( ) = >deactive_mm( ) and diff --git a/arch/arc/mm/tlb.c b/arch/arc/mm/tlb.c index 5f53050abf60..db0f0f823980 100644 --- a/arch/arc/mm/tlb.c +++ b/arch/arc/mm/tlb.c @@ -100,7 +100,7 @@ /* A copy of the ASID from the PID reg is kept in asid_cache */ -unsigned int asid_cache = MM_CTXT_FIRST_CYCLE; +DEFINE_PER_CPU(unsigned int, asid_cache) = MM_CTXT_FIRST_CYCLE; /* * Utility Routine to erase a J-TLB entry @@ -274,6 +274,7 @@ noinline void local_flush_tlb_mm(struct mm_struct *mm) void local_flush_tlb_range(struct vm_area_struct *vma, unsigned long start, unsigned long end) { + const unsigned int cpu = smp_processor_id(); unsigned long flags; /* If range @start to @end is more than 32 TLB entries deep, @@ -297,9 +298,9 @@ void local_flush_tlb_range(struct vm_area_struct *vma, unsigned long start, local_irq_save(flags); - if (vma->vm_mm->context.asid != MM_CTXT_NO_ASID) { + if (asid_mm(vma->vm_mm, cpu) != MM_CTXT_NO_ASID) { while (start < end) { - tlb_entry_erase(start | hw_pid(vma->vm_mm)); + tlb_entry_erase(start | hw_pid(vma->vm_mm, cpu)); start += PAGE_SIZE; } } @@ -346,6 +347,7 @@ void local_flush_tlb_kernel_range(unsigned long start, unsigned long end) void local_flush_tlb_page(struct vm_area_struct *vma, unsigned long page) { + const unsigned int cpu = smp_processor_id(); unsigned long flags; /* Note that it is critical that interrupts are DISABLED between @@ -353,8 +355,8 @@ void local_flush_tlb_page(struct vm_area_struct *vma, unsigned long page) */ local_irq_save(flags); - if (vma->vm_mm->context.asid != MM_CTXT_NO_ASID) { - tlb_entry_erase((page & PAGE_MASK) | hw_pid(vma->vm_mm)); + if (asid_mm(vma->vm_mm, cpu) != MM_CTXT_NO_ASID) { + tlb_entry_erase((page & PAGE_MASK) | hw_pid(vma->vm_mm, cpu)); utlb_invalidate(); } @@ -400,7 +402,7 @@ void create_tlb(struct vm_area_struct *vma, unsigned long address, pte_t *ptep) local_irq_save(flags); - tlb_paranoid_check(vma->vm_mm->context.asid, address); + tlb_paranoid_check(asid_mm(vma->vm_mm, smp_processor_id()), address); address &= PAGE_MASK; -- 2.30.2