include/asm-arm/tlb.h

   1 /*
   2  *  linux/include/asm-arm/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 #include <asm/pgalloc.h>
  23
  24 /*
  25  * TLB handling.  This allows us to remove pages from the page
  26  * tables, and efficiently handle the TLB issues.
  27  */
  28 struct mmu_gather {
  29         struct mm_struct        *mm;
  30         unsigned int            freed;
  31         unsigned int            fullmm;
  32
  33         unsigned int            flushes;
  34         unsigned int            avoided_flushes;
  35 };
  36
  37 DECLARE_PER_CPU(struct mmu_gather, mmu_gathers);
  38
  39 static inline struct mmu_gather *
  40 tlb_gather_mmu(struct mm_struct *mm, unsigned int full_mm_flush)
  41 {
  42         int cpu = smp_processor_id();
  43         struct mmu_gather *tlb = &per_cpu(mmu_gathers, cpu);
  44
  45         tlb->mm = mm;
  46         tlb->freed = 0;
  47         tlb->fullmm = full_mm_flush;
  48
  49         return tlb;
  50 }
  51
  52 static inline void
  53 tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end)
  54 {
  55         struct mm_struct *mm = tlb->mm;
  56         unsigned long freed = tlb->freed;
  57         int rss = get_mm_counter(mm, rss);
  58
  59         if (rss < freed)
  60                 freed = rss;
  61         add_mm_counter(mm, rss, -freed);
  62
  63         if (tlb->fullmm)
  64                 flush_tlb_mm(mm);
  65
  66         /* keep the page table cache within bounds */
  67         check_pgt_cache();
  68 }
  69
  70 static inline unsigned int tlb_is_full_mm(struct mmu_gather *tlb)
  71 {
  72         return tlb->fullmm;
  73 }
  74
  75 #define tlb_remove_tlb_entry(tlb,ptep,address)  do { } while (0)
  76
  77 /*
  78  * In the case of tlb vma handling, we can optimise these away in the
  79  * case where we're doing a full MM flush.  When we're doing a munmap,
  80  * the vmas are adjusted to only cover the region to be torn down.
  81  */
  82 static inline void
  83 tlb_start_vma(struct mmu_gather *tlb, struct vm_area_struct *vma)
  84 {
  85         if (!tlb->fullmm)
  86                 flush_cache_range(vma, vma->vm_start, vma->vm_end);
  87 }
  88
  89 static inline void
  90 tlb_end_vma(struct mmu_gather *tlb, struct vm_area_struct *vma)
  91 {
  92         if (!tlb->fullmm)
  93                 flush_tlb_range(vma, vma->vm_start, vma->vm_end);
  94 }
  95
  96 #define tlb_remove_page(tlb,page)       free_page_and_swap_cache(page)
  97 #define pte_free_tlb(tlb,ptep)          pte_free(ptep)
  98 #define pmd_free_tlb(tlb,pmdp)          pmd_free(pmdp)
  99
 100 #define tlb_migrate_finish(mm)          do { } while (0)
 101
 102 #endif