mm/pgtable-generic.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  mm/pgtable-generic.c
   4  *
   5  *  Generic pgtable methods declared in asm-generic/pgtable.h
   6  *
   7  *  Copyright (C) 2010  Linus Torvalds
   8  */
   9
  10 #include <linux/pagemap.h>
  11 #include <asm/tlb.h>
  12 #include <asm-generic/pgtable.h>
  13
  14 /*
  15  * If a p?d_bad entry is found while walking page tables, report
  16  * the error, before resetting entry to p?d_none.  Usually (but
  17  * very seldom) called out from the p?d_none_or_clear_bad macros.
  18  */
  19
  20 void pgd_clear_bad(pgd_t *pgd)
  21 {
  22         pgd_ERROR(*pgd);
  23         pgd_clear(pgd);
  24 }
  25
  26 void p4d_clear_bad(p4d_t *p4d)
  27 {
  28         p4d_ERROR(*p4d);
  29         p4d_clear(p4d);
  30 }
  31
  32 void pud_clear_bad(pud_t *pud)
  33 {
  34         pud_ERROR(*pud);
  35         pud_clear(pud);
  36 }
  37
  38 void pmd_clear_bad(pmd_t *pmd)
  39 {
  40         pmd_ERROR(*pmd);
  41         pmd_clear(pmd);
  42 }
  43
  44 #ifndef __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
  45 /*
  46  * Only sets the access flags (dirty, accessed), as well as write
  47  * permission. Furthermore, we know it always gets set to a "more
  48  * permissive" setting, which allows most architectures to optimize
  49  * this. We return whether the PTE actually changed, which in turn
  50  * instructs the caller to do things like update__mmu_cache.  This
  51  * used to be done in the caller, but sparc needs minor faults to
  52  * force that call on sun4c so we changed this macro slightly
  53  */
  54 int ptep_set_access_flags(struct vm_area_struct *vma,
  55                           unsigned long address, pte_t *ptep,
  56                           pte_t entry, int dirty)
  57 {
  58         int changed = !pte_same(*ptep, entry);
  59         if (changed) {
  60                 set_pte_at(vma->vm_mm, address, ptep, entry);
  61                 flush_tlb_fix_spurious_fault(vma, address);
  62         }
  63         return changed;
  64 }
  65 #endif
  66
  67 #ifndef __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
  68 int ptep_clear_flush_young(struct vm_area_struct *vma,
  69                            unsigned long address, pte_t *ptep)
  70 {
  71         int young;
  72         young = ptep_test_and_clear_young(vma, address, ptep);
  73         if (young)
  74                 flush_tlb_page(vma, address);
  75         return young;
  76 }
  77 #endif
  78
  79 #ifndef __HAVE_ARCH_PTEP_CLEAR_FLUSH
  80 pte_t ptep_clear_flush(struct vm_area_struct *vma, unsigned long address,
  81                        pte_t *ptep)
  82 {
  83         struct mm_struct *mm = (vma)->vm_mm;
  84         pte_t pte;
  85         pte = ptep_get_and_clear(mm, address, ptep);
  86         if (pte_accessible(mm, pte))
  87                 flush_tlb_page(vma, address);
  88         return pte;
  89 }
  90 #endif
  91
  92 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
  93
  94 #ifndef __HAVE_ARCH_PMDP_SET_ACCESS_FLAGS
  95 int pmdp_set_access_flags(struct vm_area_struct *vma,
  96                           unsigned long address, pmd_t *pmdp,
  97                           pmd_t entry, int dirty)
  98 {
  99         int changed = !pmd_same(*pmdp, entry);
 100         VM_BUG_ON(address & ~HPAGE_PMD_MASK);
 101         if (changed) {
 102                 set_pmd_at(vma->vm_mm, address, pmdp, entry);
 103                 flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
 104         }
 105         return changed;
 106 }
 107 #endif
 108
 109 #ifndef __HAVE_ARCH_PMDP_CLEAR_YOUNG_FLUSH
 110 int pmdp_clear_flush_young(struct vm_area_struct *vma,
 111                            unsigned long address, pmd_t *pmdp)
 112 {
 113         int young;
 114         VM_BUG_ON(address & ~HPAGE_PMD_MASK);
 115         young = pmdp_test_and_clear_young(vma, address, pmdp);
 116         if (young)
 117                 flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
 118         return young;
 119 }
 120 #endif
 121
 122 #ifndef __HAVE_ARCH_PMDP_HUGE_CLEAR_FLUSH
 123 pmd_t pmdp_huge_clear_flush(struct vm_area_struct *vma, unsigned long address,
 124                             pmd_t *pmdp)
 125 {
 126         pmd_t pmd;
 127         VM_BUG_ON(address & ~HPAGE_PMD_MASK);
 128         VM_BUG_ON((pmd_present(*pmdp) && !pmd_trans_huge(*pmdp) &&
 129                            !pmd_devmap(*pmdp)) || !pmd_present(*pmdp));
 130         pmd = pmdp_huge_get_and_clear(vma->vm_mm, address, pmdp);
 131         flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
 132         return pmd;
 133 }
 134
 135 #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
 136 pud_t pudp_huge_clear_flush(struct vm_area_struct *vma, unsigned long address,
 137                             pud_t *pudp)
 138 {
 139         pud_t pud;
 140
 141         VM_BUG_ON(address & ~HPAGE_PUD_MASK);
 142         VM_BUG_ON(!pud_trans_huge(*pudp) && !pud_devmap(*pudp));
 143         pud = pudp_huge_get_and_clear(vma->vm_mm, address, pudp);
 144         flush_pud_tlb_range(vma, address, address + HPAGE_PUD_SIZE);
 145         return pud;
 146 }
 147 #endif
 148 #endif
 149
 150 #ifndef __HAVE_ARCH_PGTABLE_DEPOSIT
 151 void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
 152                                 pgtable_t pgtable)
 153 {
 154         assert_spin_locked(pmd_lockptr(mm, pmdp));
 155
 156         /* FIFO */
 157         if (!pmd_huge_pte(mm, pmdp))
 158                 INIT_LIST_HEAD(&pgtable->lru);
 159         else
 160                 list_add(&pgtable->lru, &pmd_huge_pte(mm, pmdp)->lru);
 161         pmd_huge_pte(mm, pmdp) = pgtable;
 162 }
 163 #endif
 164
 165 #ifndef __HAVE_ARCH_PGTABLE_WITHDRAW
 166 /* no "address" argument so destroys page coloring of some arch */
 167 pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
 168 {
 169         pgtable_t pgtable;
 170
 171         assert_spin_locked(pmd_lockptr(mm, pmdp));
 172
 173         /* FIFO */
 174         pgtable = pmd_huge_pte(mm, pmdp);
 175         pmd_huge_pte(mm, pmdp) = list_first_entry_or_null(&pgtable->lru,
 176                                                           struct page, lru);
 177         if (pmd_huge_pte(mm, pmdp))
 178                 list_del(&pgtable->lru);
 179         return pgtable;
 180 }
 181 #endif
 182
 183 #ifndef __HAVE_ARCH_PMDP_INVALIDATE
 184 pmd_t pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
 185                      pmd_t *pmdp)
 186 {
 187         pmd_t old = pmdp_establish(vma, address, pmdp, pmd_mknotpresent(*pmdp));
 188         flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
 189         return old;
 190 }
 191 #endif
 192
 193 #ifndef pmdp_collapse_flush
 194 pmd_t pmdp_collapse_flush(struct vm_area_struct *vma, unsigned long address,
 195                           pmd_t *pmdp)
 196 {
 197         /*
 198          * pmd and hugepage pte format are same. So we could
 199          * use the same function.
 200          */
 201         pmd_t pmd;
 202
 203         VM_BUG_ON(address & ~HPAGE_PMD_MASK);
 204         VM_BUG_ON(pmd_trans_huge(*pmdp));
 205         pmd = pmdp_huge_get_and_clear(vma->vm_mm, address, pmdp);
 206
 207         /* collapse entails shooting down ptes not pmd */
 208         flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
 209         return pmd;
 210 }
 211 #endif
 212 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */