pgtable-generic.c

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/*
 *  mm/pgtable-generic.c
 *
 *  Generic pgtable methods declared in asm-generic/pgtable.h
 *
 *  Copyright (C) 2010  Linus Torvalds
 */

#include <linux/pagemap.h>
#include <asm/tlb.h>
#include <asm-generic/pgtable.h>

#ifndef __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
/*
 * Only sets the access flags (dirty, accessed, and
 * writable). Furthermore, we know it always gets set to a "more
 * permissive" setting, which allows most architectures to optimize
 * this. We return whether the PTE actually changed, which in turn
 * instructs the caller to do things like update__mmu_cache.  This
 * used to be done in the caller, but sparc needs minor faults to
 * force that call on sun4c so we changed this macro slightly
 */
int ptep_set_access_flags(struct vm_area_struct *vma,
              unsigned long address, pte_t *ptep,
              pte_t entry, int dirty)
{
    int changed = !pte_same(*ptep, entry);
    if (changed) {
        set_pte_at(vma->vm_mm, address, ptep, entry);
        flush_tlb_page(vma, address);
    }
    return changed;
}
#endif

#ifndef __HAVE_ARCH_PMDP_SET_ACCESS_FLAGS
int pmdp_set_access_flags(struct vm_area_struct *vma,
              unsigned long address, pmd_t *pmdp,
              pmd_t entry, int dirty)
{
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
    int changed = !pmd_same(*pmdp, entry);
    VM_BUG_ON(address & ~HPAGE_PMD_MASK);
    if (changed) {
        set_pmd_at(vma->vm_mm, address, pmdp, entry);
        flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
    }
    return changed;
#else /* CONFIG_TRANSPARENT_HUGEPAGE */
    BUG();
    return 0;
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
}
#endif

#ifndef __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
int ptep_clear_flush_young(struct vm_area_struct *vma,
               unsigned long address, pte_t *ptep)
{
    int young;
    young = ptep_test_and_clear_young(vma, address, ptep);
    if (young)
        flush_tlb_page(vma, address);
    return young;
}
#endif

#ifndef __HAVE_ARCH_PMDP_CLEAR_YOUNG_FLUSH
int pmdp_clear_flush_young(struct vm_area_struct *vma,
               unsigned long address, pmd_t *pmdp)
{
    int young;
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
    VM_BUG_ON(address & ~HPAGE_PMD_MASK);
#else
    BUG();
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
    young = pmdp_test_and_clear_young(vma, address, pmdp);
    if (young)
        flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
    return young;
}
#endif

#ifndef __HAVE_ARCH_PTEP_CLEAR_FLUSH
pte_t ptep_clear_flush(struct vm_area_struct *vma, unsigned long address,
               pte_t *ptep)
{
    pte_t pte;
    pte = ptep_get_and_clear((vma)->vm_mm, address, ptep);
    flush_tlb_page(vma, address);
    return pte;
}
#endif

#ifndef __HAVE_ARCH_PMDP_CLEAR_FLUSH
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
pmd_t pmdp_clear_flush(struct vm_area_struct *vma, unsigned long address,
               pmd_t *pmdp)
{
    pmd_t pmd;
    VM_BUG_ON(address & ~HPAGE_PMD_MASK);
    pmd = pmdp_get_and_clear(vma->vm_mm, address, pmdp);
    flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
    return pmd;
}
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
#endif

#ifndef __HAVE_ARCH_PMDP_SPLITTING_FLUSH
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
void pmdp_splitting_flush(struct vm_area_struct *vma, unsigned long address,
              pmd_t *pmdp)
{
    pmd_t pmd = pmd_mksplitting(*pmdp);
    VM_BUG_ON(address & ~HPAGE_PMD_MASK);
    set_pmd_at(vma->vm_mm, address, pmdp, pmd);
    /* tlb flush only to serialize against gup-fast */
    flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
}
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
#endif

#ifndef __HAVE_ARCH_PGTABLE_DEPOSIT
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
void pgtable_trans_huge_deposit(struct mm_struct *mm, pgtable_t pgtable)
{
    assert_spin_locked(&mm->page_table_lock);

    /* FIFO */
    if (!mm->pmd_huge_pte)
        INIT_LIST_HEAD(&pgtable->lru);
    else
        list_add(&pgtable->lru, &mm->pmd_huge_pte->lru);
    mm->pmd_huge_pte = pgtable;
}
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
#endif

#ifndef __HAVE_ARCH_PGTABLE_WITHDRAW
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
/* no "address" argument so destroys page coloring of some arch */
pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm)
{
    pgtable_t pgtable;

    assert_spin_locked(&mm->page_table_lock);

    /* FIFO */
    pgtable = mm->pmd_huge_pte;
    if (list_empty(&pgtable->lru))
        mm->pmd_huge_pte = NULL;
    else {
        mm->pmd_huge_pte = list_entry(pgtable->lru.next,
                          struct page, lru);
        list_del(&pgtable->lru);
    }
    return pgtable;
}
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
#endif

#ifndef __HAVE_ARCH_PMDP_INVALIDATE
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
void pmdp_invalidate(struct vm_area_struct *vma, unsigned long address,
             pmd_t *pmdp)
{
    set_pmd_at(vma->vm_mm, address, pmdp, pmd_mknotpresent(*pmdp));
    flush_tlb_range(vma, address, address + HPAGE_PMD_SIZE);
}
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
#endif