linux/mm/pgtable-generic.c
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   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
  21void pgd_clear_bad(pgd_t *pgd)
  22{
  23        pgd_ERROR(*pgd);
  24        pgd_clear(pgd);
  25}
  26
  27#ifndef __PAGETABLE_P4D_FOLDED
  28void p4d_clear_bad(p4d_t *p4d)
  29{
  30        p4d_ERROR(*p4d);
  31        p4d_clear(p4d);
  32}
  33#endif
  34
  35#ifndef __PAGETABLE_PUD_FOLDED
  36void 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 */
  48void 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 */
  64int 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
  78int 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
  90pte_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
 105int 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
 120int 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
 133pmd_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));
 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
 146pud_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
 161void 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 */
 177pgtable_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
 194pmd_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
 204pmd_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 */
 223
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