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 = mm->rss;
  58
  59         if (rss < freed)
  60                 freed = rss;
  61         mm->rss = rss - freed;
  62
  63         if (freed) {
  64                 flush_tlb_mm(mm);
  65                 tlb->flushes++;
  66         } else {
  67                 tlb->avoided_flushes++;
  68         }
  69
  70         /* keep the page table cache within bounds */
  71         check_pgt_cache();
  72 }
  73
  74 static inline unsigned int
  75 tlb_is_full_mm(struct mmu_gather *tlb)
  76 {
  77      return tlb->fullmm;
  78 }
  79
  80 #define tlb_remove_tlb_entry(tlb,ptep,address)  do { } while (0)
  81
  82 #define tlb_start_vma(tlb,vma)                                          \
  83         do {                                                            \
  84                 if (!tlb->fullmm)                                       \
  85                         flush_cache_range(vma, vma->vm_start, vma->vm_end); \
  86         } while (0)
  87
  88 #define tlb_end_vma(tlb,vma)                    do { } while (0)
  89
  90 #define tlb_remove_page(tlb,page)       free_page_and_swap_cache(page)
  91 #define pte_free_tlb(tlb,ptep)          pte_free(ptep)
  92 #define pmd_free_tlb(tlb,pmdp)          pmd_free(pmdp)
  93
  94 #endif