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 <linux/mm_inline.h>
  14 #include <asm/tlb.h>
  15
  16 /*
  17  * If a p?d_bad entry is found while walking page tables, report
  18  * the error, before resetting entry to p?d_none.  Usually (but
  19  * very seldom) called out from the p?d_none_or_clear_bad macros.
  20  */
  21
  22 void pgd_clear_bad(pgd_t *pgd)
  23 {
  24         pgd_ERROR(*pgd);
  25         pgd_clear(pgd);
  26 }
  27
  28 #ifndef __PAGETABLE_P4D_FOLDED
  29 void p4d_clear_bad(p4d_t *p4d)
  30 {
  31         p4d_ERROR(*p4d);
  32         p4d_clear(p4d);
  33 }
  34 #endif
  35
  36 #ifndef __PAGETABLE_PUD_FOLDED
  37 void pud_clear_bad(pud_t *pud)
  38 {
  39         pud_ERROR(*pud);
  40         pud_clear(pud);
  41 }
  42 #endif
  43
  44 /*
  45  * Note that the pmd variant below can't be stub'ed out just as for p4d/pud
  46  * above. pmd folding is special and typically pmd_* macros refer to upper
  47  * level even when folded
  48  */
  49 void pmd_clear_bad(pmd_t *pmd)
  50 {
  51         pmd_ERROR(*pmd);
  52         pmd_clear(pmd);
  53 }
  54
  55 #ifndef __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
  56 /*
  57  * Only sets the access flags (dirty, accessed), as well as write
  58  * permission. Furthermore, we know it always gets set to a "more
  59  * permissive" setting, which allows most architectures to optimize
  60  * this. We return whether the PTE actually changed, which in turn
  61  * instructs the caller to do things like update__mmu_cache.  This
  62  * used to be done in the caller, but sparc needs minor faults to
  63  * force that call on sun4c so we changed this macro slightly
  64  */
  65 int ptep_set_access_flags(struct vm_area_struct *vma,
  66                           unsigned long address, pte_t *ptep,
  67                           pte_t entry, int dirty)
  68 {
  69         int changed = !pte_same(*ptep, entry);
  70         if (changed) {
  71                 set_pte_at(vma->vm_mm, address, ptep, entry);
  72                 flush_tlb_fix_spurious_fault(vma, address);
  73         }
  74         return changed;
  75 }
  76 #endif
  77
  78 #ifndef __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
  79 int ptep_clear_flush_young(struct vm_area_struct *vma,
  80                            unsigned long address, pte_t *ptep)
  81 {
  82         int young;
  83         young = ptep_test_and_clear_young(vma, address, ptep);
  84         if (young)
  85                 flush_tlb_page(vma, address);
  86         return young;
  87 }
  88 #endif
  89
  90 #ifndef __HAVE_ARCH_PTEP_CLEAR_FLUSH
  91 pte_t ptep_clear_flush(struct vm_area_struct *vma, unsigned long address,
  92                        pte_t *ptep)
  93 {
  94         struct mm_struct *mm = (vma)->vm_mm;
  95         pte_t pte;
  96         pte = ptep_get_and_clear(mm, address, ptep);
  97         if (pte_accessible(mm, pte))
  98                 flush_tlb_page(vma, address);
  99         return pte;
 100 }
 101 #endif
 102
 103 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 104
 105 #ifndef __HAVE_ARCH_PMDP_SET_ACCESS_FLAGS
 106 int pmdp_set_access_flags(struct vm_area_struct *vma,
 107                           unsigned long address, pmd_t *pmdp,
 108                           pmd_t entry, int dirty)
 109 {
 110         int changed = !pmd_same(*pmdp, entry);
 111         VM_BUG_ON(address & ~HPAGE_PMD_MASK);
 112         if (changed) {
 113                 set_pmd_at(vma->vm_mm, address, pmdp, entry);
 114                 flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
 115         }
 116         return changed;
 117 }
 118 #endif
 119
 120 #ifndef __HAVE_ARCH_PMDP_CLEAR_YOUNG_FLUSH
 121 int pmdp_clear_flush_young(struct vm_area_struct *vma,
 122                            unsigned long address, pmd_t *pmdp)
 123 {
 124         int young;
 125         VM_BUG_ON(address & ~HPAGE_PMD_MASK);
 126         young = pmdp_test_and_clear_young(vma, address, pmdp);
 127         if (young)
 128                 flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
 129         return young;
 130 }
 131 #endif
 132
 133 #ifndef __HAVE_ARCH_PMDP_HUGE_CLEAR_FLUSH
 134 pmd_t pmdp_huge_clear_flush(struct vm_area_struct *vma, unsigned long address,
 135                             pmd_t *pmdp)
 136 {
 137         pmd_t pmd;
 138         VM_BUG_ON(address & ~HPAGE_PMD_MASK);
 139         VM_BUG_ON(pmd_present(*pmdp) && !pmd_trans_huge(*pmdp) &&
 140                            !pmd_devmap(*pmdp));
 141         pmd = pmdp_huge_get_and_clear(vma->vm_mm, address, pmdp);
 142         flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
 143         return pmd;
 144 }
 145
 146 #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
 147 pud_t pudp_huge_clear_flush(struct vm_area_struct *vma, unsigned long address,
 148                             pud_t *pudp)
 149 {
 150         pud_t pud;
 151
 152         VM_BUG_ON(address & ~HPAGE_PUD_MASK);
 153         VM_BUG_ON(!pud_trans_huge(*pudp) && !pud_devmap(*pudp));
 154         pud = pudp_huge_get_and_clear(vma->vm_mm, address, pudp);
 155         flush_pud_tlb_range(vma, address, address + HPAGE_PUD_SIZE);
 156         return pud;
 157 }
 158 #endif
 159 #endif
 160
 161 #ifndef __HAVE_ARCH_PGTABLE_DEPOSIT
 162 void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp,
 163                                 pgtable_t pgtable)
 164 {
 165         assert_spin_locked(pmd_lockptr(mm, pmdp));
 166
 167         /* FIFO */
 168         if (!pmd_huge_pte(mm, pmdp))
 169                 INIT_LIST_HEAD(&pgtable->lru);
 170         else
 171                 list_add(&pgtable->lru, &pmd_huge_pte(mm, pmdp)->lru);
 172         pmd_huge_pte(mm, pmdp) = pgtable;
 173 }
 174 #endif
 175
 176 #ifndef __HAVE_ARCH_PGTABLE_WITHDRAW
 177 /* no "address" argument so destroys page coloring of some arch */
 178 pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp)
 179 {
 180         pgtable_t pgtable;
 181
 182         assert_spin_locked(pmd_lockptr(mm, pmdp));
 183
 184         /* FIFO */
 185         pgtable = pmd_huge_pte(mm, pmdp);
 186         pmd_huge_pte(mm, pmdp) = list_first_entry_or_null(&pgtable->lru,
 187                                                           struct page, lru);
 188         if (pmd_huge_pte(mm, pmdp))
 189                 list_del(&pgtable->lru);
 190         return pgtable;
 191 }
 192 #endif
 193
 194 #ifndef __HAVE_ARCH_PMDP_INVALIDATE
 195 pmd_t pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
 196                      pmd_t *pmdp)
 197 {
 198         pmd_t old = pmdp_establish(vma, address, pmdp, pmd_mkinvalid(*pmdp));
 199         flush_pmd_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
 200         return old;
 201 }
 202 #endif
 203
 204 #ifndef __HAVE_ARCH_PMDP_INVALIDATE_AD
 205 pmd_t pmdp_invalidate_ad(struct vm_area_struct *vma, unsigned long address,
 206                          pmd_t *pmdp)
 207 {
 208         return pmdp_invalidate(vma, address, pmdp);
 209 }
 210 #endif
 211
 212 #ifndef pmdp_collapse_flush
 213 pmd_t pmdp_collapse_flush(struct vm_area_struct *vma, unsigned long address,
 214                           pmd_t *pmdp)
 215 {
 216         /*
 217          * pmd and hugepage pte format are same. So we could
 218          * use the same function.
 219          */
 220         pmd_t pmd;
 221
 222         VM_BUG_ON(address & ~HPAGE_PMD_MASK);
 223         VM_BUG_ON(pmd_trans_huge(*pmdp));
 224         pmd = pmdp_huge_get_and_clear(vma->vm_mm, address, pmdp);
 225
 226         /* collapse entails shooting down ptes not pmd */
 227         flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
 228         return pmd;
 229 }
 230 #endif
 231 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */