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            fullmm;
  31 };
  32
  33 DECLARE_PER_CPU(struct mmu_gather, mmu_gathers);
  34
  35 static inline struct mmu_gather *
  36 tlb_gather_mmu(struct mm_struct *mm, unsigned int full_mm_flush)
  37 {
  38         struct mmu_gather *tlb = &get_cpu_var(mmu_gathers);
  39
  40         tlb->mm = mm;
  41         tlb->fullmm = full_mm_flush;
  42
  43         return tlb;
  44 }
  45
  46 static inline void
  47 tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end)
  48 {
  49         if (tlb->fullmm)
  50                 flush_tlb_mm(tlb->mm);
  51
  52         /* keep the page table cache within bounds */
  53         check_pgt_cache();
  54
  55         put_cpu_var(mmu_gathers);
  56 }
  57
  58 #define tlb_remove_tlb_entry(tlb,ptep,address)  do { } while (0)
  59
  60 /*
  61  * In the case of tlb vma handling, we can optimise these away in the
  62  * case where we're doing a full MM flush.  When we're doing a munmap,
  63  * the vmas are adjusted to only cover the region to be torn down.
  64  */
  65 static inline void
  66 tlb_start_vma(struct mmu_gather *tlb, struct vm_area_struct *vma)
  67 {
  68         if (!tlb->fullmm)
  69                 flush_cache_range(vma, vma->vm_start, vma->vm_end);
  70 }
  71
  72 static inline void
  73 tlb_end_vma(struct mmu_gather *tlb, struct vm_area_struct *vma)
  74 {
  75         if (!tlb->fullmm)
  76                 flush_tlb_range(vma, vma->vm_start, vma->vm_end);
  77 }
  78
  79 #define tlb_remove_page(tlb,page)       free_page_and_swap_cache(page)
  80 #define pte_free_tlb(tlb,ptep)          pte_free(ptep)
  81 #define pmd_free_tlb(tlb,pmdp)          pmd_free(pmdp)
  82
  83 #define tlb_migrate_finish(mm)          do { } while (0)
  84
  85 #endif