mm/pgtable-generic.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  *  mm/pgtable-generic.c
   4  *
   5  *  Generic pgtable methods declared in linux/pgtable.h
   6  *
   7  *  Copyright (C) 2010  Linus Torvalds
   8  */
   9
  10 #include <linux/pagemap.h>
  11 #include <linux/hugetlb.h>
  12 #include <linux/pgtable.h>
  13 #include <asm/tlb.h>
  14
  15 /*
  16  * If a p?d_bad entry is found while walking page tables, report
  17  * the error, before resetting entry to p?d_none.  Usually (but
  18  * very seldom) called out from the p?d_none_or_clear_bad macros.
  19  */
  20
  21 void pgd_clear_bad(pgd_t *pgd)
  22 {
  23         pgd_ERROR(*pgd);
  24         pgd_clear(pgd);
  25 }
  26
  27 #ifndef __PAGETABLE_P4D_FOLDED
  28 void p4d_clear_bad(p4d_t *p4d)
  29 {
  30         p4d_ERROR(*p4d);
  31         p4d_clear(p4d);
  32 }
  33 #endif
  34
  35 #ifndef __PAGETABLE_PUD_FOLDED
  36 void pud_clear_bad(pud_t *pud)
  37 {
  38         pud_ERROR(*pud);
  39         pud_clear(pud);
  40 }
  41 #endif
  42
  43 /*
  44  * Note that the pmd variant below can't be stub'ed out just as for p4d/pud
  45  * above. pmd folding is special and typically pmd_* macros refer to upper
  46  * level even when folded
  47  */
  48 void pmd_clear_bad(pmd_t *pmd)
  49 {
  50         pmd_ERROR(*pmd);
  51         pmd_clear(pmd);
  52 }
  53
  54 #ifndef __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
  55 /*
  56  * Only sets the access flags (dirty, accessed), as well as write
  57  * permission. Furthermore, we know it always gets set to a "more
  58  * permissive" setting, which allows most architectures to optimize
  59  * this. We return whether the PTE actually changed, which in turn
  60  * instructs the caller to do things like update__mmu_cache.  This
  61  * used to be done in the caller, but sparc needs minor faults to
  62  * force that call on sun4c so we changed this macro slightly
  63  */
  64 int ptep_set_access_flags(struct vm_area_struct *vma,
  65                           unsigned long address, pte_t *ptep,
  66                           pte_t entry, int dirty)
  67 {
  68         int changed = !pte_same(*ptep, entry);
  69         if (changed) {
  70                 set_pte_at(vma->vm_mm, address, ptep, entry);
  71                 flush_tlb_fix_spurious_fault(vma, address);
  72         }
  73         return changed;
  74 }
  75 #endif
  76
  77 #ifndef __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
  78 int ptep_clear_flush_young(struct vm_area_struct *vma,
  79                            unsigned long address, pte_t *ptep)
  80 {
  81         int young;
  82         young = ptep_test_and_clear_young(vma, address, ptep);
  83         if (young)
  84                 flush_tlb_page(vma, address);
  85         return young;
  86 }
  87 #endif
  88
  89 #ifndef __HAVE_ARCH_PTEP_CLEAR_FLUSH
  90 pte_t ptep_clear_flush(struct vm_area_struct *vma, unsigned long address,
  91                        pte_t *ptep)
  92 {
  93         struct mm_struct *mm = (vma)->vm_mm;
  94         pte_t pte;
  95         pte = ptep_get_and_clear(mm, address, ptep);
  96         if (pte_accessible(mm, pte))
  97                 flush_tlb_page(vma, address);
  98         return pte;
  99 }
 100 #endif
 101
 102 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 103
 104 #ifndef __HAVE_ARCH_PMDP_SET_ACCESS_FLAGS
 105 int pmdp_set_access_flags(struct vm_area_struct *vma,
 106                           unsigned long address, pmd_t *pmdp,
 107                           pmd_t entry, int dirty)
 108 {
 109         int changed = !pmd_same(*pmdp, entry);
 110         VM_BUG_ON(address & ~HPAGE_PMD_MASK);
 111         if (changed) {
 112                 set_pmd_at(vma->vm_mm, address, pmdp, entry);
 113                 flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
 114         }
 115         return changed;
 116 }
 117 #endif
 118
 119 #ifndef __HAVE_ARCH_PMDP_CLEAR_YOUNG_FLUSH
 120 int pmdp_clear_flush_young(struct vm_area_struct *vma,
 121                            unsigned long address, pmd_t *pmdp)
 122 {
 123         int young;
 124         VM_BUG_ON(address & ~HPAGE_PMD_MASK);
 125         young = pmdp_test_and_clear_young(vma, address, pmdp);
 126         if (young)
 127                 flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
 128         return young;
 129 }
 130 #endif
 131
 132 #ifndef __HAVE_ARCH_PMDP_HUGE_CLEAR_FLUSH
 133 pmd_t pmdp_huge_clear_flush(struct vm_area_struct *vma, unsigned long address,
 134                             pmd_t *pmdp)
 135 {
 136         pmd_t pmd;
 137         VM_BUG_ON(address & ~HPAGE_PMD_MASK);
 138         VM_BUG_ON((pmd_present(*pmdp) && !pmd_trans_huge(*pmdp) &&
 139                            !pmd_devmap(*pmdp)) || !pmd_present(*pmdp));
 140         pmd = pmdp_huge_get_and_clear(vma->vm_mm, address, pmdp);
 141         flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
 142         return pmd;
 143 }
 144
 145 #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
 146 pud_t pudp_huge_clear_flush(struct vm_area_struct *vma, unsigned long address,
 147                             pud_t *pudp)
 148 {
 149         pud_t pud;
 150
 151         VM_BUG_ON(address & ~HPAGE_PUD_MASK);
 152         VM_BUG_ON(!pud_trans_huge(*pudp) && !pud_devmap(*pudp));
 153         pud = pudp_huge_get_and_clear(vma->vm_mm, address, pudp);
 154         flush_pud_tlb_range(vma, address, address + HPAGE_PUD_SIZE);
 155         return pud;
 156 }
 157 #endif
 158 #endif
 159
 160 #ifndef __HAVE_ARCH_PGTABLE_DEPOSIT
 161 void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
 162                                 pgtable_t pgtable)
 163 {
 164         assert_spin_locked(pmd_lockptr(mm, pmdp));
 165
 166         /* FIFO */
 167         if (!pmd_huge_pte(mm, pmdp))
 168                 INIT_LIST_HEAD(&pgtable->lru);
 169         else
 170                 list_add(&pgtable->lru, &pmd_huge_pte(mm, pmdp)->lru);
 171         pmd_huge_pte(mm, pmdp) = pgtable;
 172 }
 173 #endif
 174
 175 #ifndef __HAVE_ARCH_PGTABLE_WITHDRAW
 176 /* no "address" argument so destroys page coloring of some arch */
 177 pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
 178 {
 179         pgtable_t pgtable;
 180
 181         assert_spin_locked(pmd_lockptr(mm, pmdp));
 182
 183         /* FIFO */
 184         pgtable = pmd_huge_pte(mm, pmdp);
 185         pmd_huge_pte(mm, pmdp) = list_first_entry_or_null(&pgtable->lru,
 186                                                           struct page, lru);
 187         if (pmd_huge_pte(mm, pmdp))
 188                 list_del(&pgtable->lru);
 189         return pgtable;
 190 }
 191 #endif
 192
 193 #ifndef __HAVE_ARCH_PMDP_INVALIDATE
 194 pmd_t pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
 195                      pmd_t *pmdp)
 196 {
 197         pmd_t old = pmdp_establish(vma, address, pmdp, pmd_mkinvalid(*pmdp));
 198         flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
 199         return old;
 200 }
 201 #endif
 202
 203 #ifndef pmdp_collapse_flush
 204 pmd_t pmdp_collapse_flush(struct vm_area_struct *vma, unsigned long address,
 205                           pmd_t *pmdp)
 206 {
 207         /*
 208          * pmd and hugepage pte format are same. So we could
 209          * use the same function.
 210          */
 211         pmd_t pmd;
 212
 213         VM_BUG_ON(address & ~HPAGE_PMD_MASK);
 214         VM_BUG_ON(pmd_trans_huge(*pmdp));
 215         pmd = pmdp_huge_get_and_clear(vma->vm_mm, address, pmdp);
 216
 217         /* collapse entails shooting down ptes not pmd */
 218         flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
 219         return pmd;
 220 }
 221 #endif
 222 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */