include/asm-um/tlb.h

   1 #ifndef __UM_TLB_H
   2 #define __UM_TLB_H
   3
   4 #include <linux/swap.h>
   5 #include <asm/percpu.h>
   6 #include <asm/pgalloc.h>
   7 #include <asm/tlbflush.h>
   8
   9 #define tlb_start_vma(tlb, vma) do { } while (0)
  10 #define tlb_end_vma(tlb, vma) do { } while (0)
  11 #define tlb_flush(tlb) flush_tlb_mm((tlb)->mm)
  12
  13 /* struct mmu_gather is an opaque type used by the mm code for passing around
  14  * any data needed by arch specific code for tlb_remove_page.
  15  */
  16 struct mmu_gather {
  17         struct mm_struct        *mm;
  18         unsigned int            need_flush; /* Really unmapped some ptes? */
  19         unsigned long           start;
  20         unsigned long           end;
  21         unsigned int            fullmm; /* non-zero means full mm flush */
  22 };
  23
  24 /* Users of the generic TLB shootdown code must declare this storage space. */
  25 DECLARE_PER_CPU(struct mmu_gather, mmu_gathers);
  26
  27 static inline void __tlb_remove_tlb_entry(struct mmu_gather *tlb, pte_t *ptep,
  28                                           unsigned long address)
  29 {
  30         if (tlb->start > address)
  31                 tlb->start = address;
  32         if (tlb->end < address + PAGE_SIZE)
  33                 tlb->end = address + PAGE_SIZE;
  34 }
  35
  36 static inline void init_tlb_gather(struct mmu_gather *tlb)
  37 {
  38         tlb->need_flush = 0;
  39
  40         tlb->start = TASK_SIZE;
  41         tlb->end = 0;
  42
  43         if (tlb->fullmm) {
  44                 tlb->start = 0;
  45                 tlb->end = TASK_SIZE;
  46         }
  47 }
  48
  49 /* tlb_gather_mmu
  50  *      Return a pointer to an initialized struct mmu_gather.
  51  */
  52 static inline struct mmu_gather *
  53 tlb_gather_mmu(struct mm_struct *mm, unsigned int full_mm_flush)
  54 {
  55         struct mmu_gather *tlb = &get_cpu_var(mmu_gathers);
  56
  57         tlb->mm = mm;
  58         tlb->fullmm = full_mm_flush;
  59
  60         init_tlb_gather(tlb);
  61
  62         return tlb;
  63 }
  64
  65 extern void flush_tlb_mm_range(struct mm_struct *mm, unsigned long start,
  66                                unsigned long end);
  67
  68 static inline void
  69 tlb_flush_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end)
  70 {
  71         if (!tlb->need_flush)
  72                 return;
  73
  74         flush_tlb_mm_range(tlb->mm, tlb->start, tlb->end);
  75         init_tlb_gather(tlb);
  76 }
  77
  78 /* tlb_finish_mmu
  79  *      Called at the end of the shootdown operation to free up any resources
  80  *      that were required.
  81  */
  82 static inline void
  83 tlb_finish_mmu(struct mmu_gather *tlb, unsigned long start, unsigned long end)
  84 {
  85         tlb_flush_mmu(tlb, start, end);
  86
  87         /* keep the page table cache within bounds */
  88         check_pgt_cache();
  89
  90         put_cpu_var(mmu_gathers);
  91 }
  92
  93 /* tlb_remove_page
  94  *      Must perform the equivalent to __free_pte(pte_get_and_clear(ptep)),
  95  *      while handling the additional races in SMP caused by other CPUs
  96  *      caching valid mappings in their TLBs.
  97  */
  98 static inline void tlb_remove_page(struct mmu_gather *tlb, struct page *page)
  99 {
 100         tlb->need_flush = 1;
 101         free_page_and_swap_cache(page);
 102         return;
 103 }
 104
 105 /**
 106  * tlb_remove_tlb_entry - remember a pte unmapping for later tlb invalidation.
 107  *
 108  * Record the fact that pte's were really umapped in ->need_flush, so we can
 109  * later optimise away the tlb invalidate.   This helps when userspace is
 110  * unmapping already-unmapped pages, which happens quite a lot.
 111  */
 112 #define tlb_remove_tlb_entry(tlb, ptep, address)                \
 113         do {                                                    \
 114                 tlb->need_flush = 1;                            \
 115                 __tlb_remove_tlb_entry(tlb, ptep, address);     \
 116         } while (0)
 117
 118 #define pte_free_tlb(tlb, ptep) __pte_free_tlb(tlb, ptep)
 119
 120 #define pud_free_tlb(tlb, pudp) __pud_free_tlb(tlb, pudp)
 121
 122 #define pmd_free_tlb(tlb, pmdp) __pmd_free_tlb(tlb, pmdp)
 123
 124 #define tlb_migrate_finish(mm) do {} while (0)
 125
 126 #endif