mm/pgtable-generic.c

   1 /*
   2  *  mm/pgtable-generic.c
   3  *
   4  *  Generic pgtable methods declared in asm-generic/pgtable.h
   5  *
   6  *  Copyright (C) 2010  Linus Torvalds
   7  */
   8
   9 #include <linux/pagemap.h>
  10 #include <asm/tlb.h>
  11 #include <asm-generic/pgtable.h>
  12
  13 /*
  14  * If a p?d_bad entry is found while walking page tables, report
  15  * the error, before resetting entry to p?d_none.  Usually (but
  16  * very seldom) called out from the p?d_none_or_clear_bad macros.
  17  */
  18
  19 void pgd_clear_bad(pgd_t *pgd)
  20 {
  21         pgd_ERROR(*pgd);
  22         pgd_clear(pgd);
  23 }
  24
  25 void p4d_clear_bad(p4d_t *p4d)
  26 {
  27         p4d_ERROR(*p4d);
  28         p4d_clear(p4d);
  29 }
  30
  31 void pud_clear_bad(pud_t *pud)
  32 {
  33         pud_ERROR(*pud);
  34         pud_clear(pud);
  35 }
  36
  37 void pmd_clear_bad(pmd_t *pmd)
  38 {
  39         pmd_ERROR(*pmd);
  40         pmd_clear(pmd);
  41 }
  42
  43 #ifndef __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
  44 /*
  45  * Only sets the access flags (dirty, accessed), as well as write
  46  * permission. Furthermore, we know it always gets set to a "more
  47  * permissive" setting, which allows most architectures to optimize
  48  * this. We return whether the PTE actually changed, which in turn
  49  * instructs the caller to do things like update__mmu_cache.  This
  50  * used to be done in the caller, but sparc needs minor faults to
  51  * force that call on sun4c so we changed this macro slightly
  52  */
  53 int ptep_set_access_flags(struct vm_area_struct *vma,
  54                           unsigned long address, pte_t *ptep,
  55                           pte_t entry, int dirty)
  56 {
  57         int changed = !pte_same(*ptep, entry);
  58         if (changed) {
  59                 set_pte_at(vma->vm_mm, address, ptep, entry);
  60                 flush_tlb_fix_spurious_fault(vma, address);
  61         }
  62         return changed;
  63 }
  64 #endif
  65
  66 #ifndef __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
  67 int ptep_clear_flush_young(struct vm_area_struct *vma,
  68                            unsigned long address, pte_t *ptep)
  69 {
  70         int young;
  71         young = ptep_test_and_clear_young(vma, address, ptep);
  72         if (young)
  73                 flush_tlb_page(vma, address);
  74         return young;
  75 }
  76 #endif
  77
  78 #ifndef __HAVE_ARCH_PTEP_CLEAR_FLUSH
  79 pte_t ptep_clear_flush(struct vm_area_struct *vma, unsigned long address,
  80                        pte_t *ptep)
  81 {
  82         struct mm_struct *mm = (vma)->vm_mm;
  83         pte_t pte;
  84         pte = ptep_get_and_clear(mm, address, ptep);
  85         if (pte_accessible(mm, pte))
  86                 flush_tlb_page(vma, address);
  87         return pte;
  88 }
  89 #endif
  90
  91 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
  92
  93 #ifndef __HAVE_ARCH_PMDP_SET_ACCESS_FLAGS
  94 int pmdp_set_access_flags(struct vm_area_struct *vma,
  95                           unsigned long address, pmd_t *pmdp,
  96                           pmd_t entry, int dirty)
  97 {
  98         int changed = !pmd_same(*pmdp, entry);
  99         VM_BUG_ON(address & ~HPAGE_PMD_MASK);
 100         if (changed) {
 101                 set_pmd_at(vma->vm_mm, address, pmdp, entry);
 102                 flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
 103         }
 104         return changed;
 105 }
 106 #endif
 107
 108 #ifndef __HAVE_ARCH_PMDP_CLEAR_YOUNG_FLUSH
 109 int pmdp_clear_flush_young(struct vm_area_struct *vma,
 110                            unsigned long address, pmd_t *pmdp)
 111 {
 112         int young;
 113         VM_BUG_ON(address & ~HPAGE_PMD_MASK);
 114         young = pmdp_test_and_clear_young(vma, address, pmdp);
 115         if (young)
 116                 flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
 117         return young;
 118 }
 119 #endif
 120
 121 #ifndef __HAVE_ARCH_PMDP_HUGE_CLEAR_FLUSH
 122 pmd_t pmdp_huge_clear_flush(struct vm_area_struct *vma, unsigned long address,
 123                             pmd_t *pmdp)
 124 {
 125         pmd_t pmd;
 126         VM_BUG_ON(address & ~HPAGE_PMD_MASK);
 127         VM_BUG_ON((pmd_present(*pmdp) && !pmd_trans_huge(*pmdp) &&
 128                            !pmd_devmap(*pmdp)) || !pmd_present(*pmdp));
 129         pmd = pmdp_huge_get_and_clear(vma->vm_mm, address, pmdp);
 130         flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
 131         return pmd;
 132 }
 133
 134 #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
 135 pud_t pudp_huge_clear_flush(struct vm_area_struct *vma, unsigned long address,
 136                             pud_t *pudp)
 137 {
 138         pud_t pud;
 139
 140         VM_BUG_ON(address & ~HPAGE_PUD_MASK);
 141         VM_BUG_ON(!pud_trans_huge(*pudp) && !pud_devmap(*pudp));
 142         pud = pudp_huge_get_and_clear(vma->vm_mm, address, pudp);
 143         flush_pud_tlb_range(vma, address, address + HPAGE_PUD_SIZE);
 144         return pud;
 145 }
 146 #endif
 147 #endif
 148
 149 #ifndef __HAVE_ARCH_PGTABLE_DEPOSIT
 150 void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
 151                                 pgtable_t pgtable)
 152 {
 153         assert_spin_locked(pmd_lockptr(mm, pmdp));
 154
 155         /* FIFO */
 156         if (!pmd_huge_pte(mm, pmdp))
 157                 INIT_LIST_HEAD(&pgtable->lru);
 158         else
 159                 list_add(&pgtable->lru, &pmd_huge_pte(mm, pmdp)->lru);
 160         pmd_huge_pte(mm, pmdp) = pgtable;
 161 }
 162 #endif
 163
 164 #ifndef __HAVE_ARCH_PGTABLE_WITHDRAW
 165 /* no "address" argument so destroys page coloring of some arch */
 166 pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
 167 {
 168         pgtable_t pgtable;
 169
 170         assert_spin_locked(pmd_lockptr(mm, pmdp));
 171
 172         /* FIFO */
 173         pgtable = pmd_huge_pte(mm, pmdp);
 174         pmd_huge_pte(mm, pmdp) = list_first_entry_or_null(&pgtable->lru,
 175                                                           struct page, lru);
 176         if (pmd_huge_pte(mm, pmdp))
 177                 list_del(&pgtable->lru);
 178         return pgtable;
 179 }
 180 #endif
 181
 182 #ifndef __HAVE_ARCH_PMDP_INVALIDATE
 183 void pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
 184                      pmd_t *pmdp)
 185 {
 186         pmd_t entry = *pmdp;
 187         set_pmd_at(vma->vm_mm, address, pmdp, pmd_mknotpresent(entry));
 188         flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
 189 }
 190 #endif
 191
 192 #ifndef pmdp_collapse_flush
 193 pmd_t pmdp_collapse_flush(struct vm_area_struct *vma, unsigned long address,
 194                           pmd_t *pmdp)
 195 {
 196         /*
 197          * pmd and hugepage pte format are same. So we could
 198          * use the same function.
 199          */
 200         pmd_t pmd;
 201
 202         VM_BUG_ON(address & ~HPAGE_PMD_MASK);
 203         VM_BUG_ON(pmd_trans_huge(*pmdp));
 204         pmd = pmdp_huge_get_and_clear(vma->vm_mm, address, pmdp);
 205
 206         /* collapse entails shooting down ptes not pmd */
 207         flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
 208         return pmd;
 209 }
 210 #endif
 211 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */