include/asm-um/tlb.h

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