arch/arm/include/asm/tlb.h

   1 /*
   2  *  arch/arm/include/asm/tlb.h
   3  *
   4  *  Copyright (C) 2002 Russell King
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License version 2 as
   8  * published by the Free Software Foundation.
   9  *
  10  *  Experimentation shows that on a StrongARM, it appears to be faster
  11  *  to use the "invalidate whole tlb" rather than "invalidate single
  12  *  tlb" for this.
  13  *
  14  *  This appears true for both the process fork+exit case, as well as
  15  *  the munmap-large-area case.
  16  */
  17 #ifndef __ASMARM_TLB_H
  18 #define __ASMARM_TLB_H
  19
  20 #include <asm/cacheflush.h>
  21 #include <asm/tlbflush.h>
  22
  23 #ifndef CONFIG_MMU
  24
  25 #include <linux/pagemap.h>
  26 #include <asm-generic/tlb.h>
  27
  28 #else /* !CONFIG_MMU */
  29
  30 #include <asm/pgalloc.h>
  31
  32 /*
  33  * TLB handling.  This allows us to remove pages from the page
  34  * tables, and efficiently handle the TLB issues.
  35  */
  36 struct mmu_gather {
  37         struct mm_struct        *mm;
  38         unsigned int            fullmm;
  39         unsigned long           range_start;
  40         unsigned long           range_end;
  41 };
  42
  43 DECLARE_PER_CPU(struct mmu_gather, mmu_gathers);
  44
  45 static inline struct mmu_gather *
  46 tlb_gather_mmu(struct mm_struct *mm, unsigned int full_mm_flush)
  47 {
  48         struct mmu_gather *tlb = &get_cpu_var(mmu_gathers);
  49
  50         tlb->mm = mm;
  51         tlb->fullmm = full_mm_flush;
  52
  53         return tlb;
  54 }
  55
  56 static inline void
  57 tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end)
  58 {
  59         if (tlb->fullmm)
  60                 flush_tlb_mm(tlb->mm);
  61
  62         /* keep the page table cache within bounds */
  63         check_pgt_cache();
  64
  65         put_cpu_var(mmu_gathers);
  66 }
  67
  68 /*
  69  * Memorize the range for the TLB flush.
  70  */
  71 static inline void
  72 tlb_remove_tlb_entry(struct mmu_gather *tlb, pte_t *ptep, unsigned long addr)
  73 {
  74         if (!tlb->fullmm) {
  75                 if (addr < tlb->range_start)
  76                         tlb->range_start = addr;
  77                 if (addr + PAGE_SIZE > tlb->range_end)
  78                         tlb->range_end = addr + PAGE_SIZE;
  79         }
  80 }
  81
  82 /*
  83  * In the case of tlb vma handling, we can optimise these away in the
  84  * case where we're doing a full MM flush.  When we're doing a munmap,
  85  * the vmas are adjusted to only cover the region to be torn down.
  86  */
  87 static inline void
  88 tlb_start_vma(struct mmu_gather *tlb, struct vm_area_struct *vma)
  89 {
  90         if (!tlb->fullmm) {
  91                 flush_cache_range(vma, vma->vm_start, vma->vm_end);
  92                 tlb->range_start = TASK_SIZE;
  93                 tlb->range_end = 0;
  94         }
  95 }
  96
  97 static inline void
  98 tlb_end_vma(struct mmu_gather *tlb, struct vm_area_struct *vma)
  99 {
 100         if (!tlb->fullmm && tlb->range_end > 0)
 101                 flush_tlb_range(vma, tlb->range_start, tlb->range_end);
 102 }
 103
 104 #define tlb_remove_page(tlb,page)       free_page_and_swap_cache(page)
 105 #define pte_free_tlb(tlb, ptep)         pte_free((tlb)->mm, ptep)
 106 #define pmd_free_tlb(tlb, pmdp)         pmd_free((tlb)->mm, pmdp)
 107
 108 #define tlb_migrate_finish(mm)          do { } while (0)
 109
 110 #endif /* CONFIG_MMU */
 111 #endif