/*
   *  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), as well as write 
   * permission. 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_fix_spurious_fault(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);

  	if (pte_accessible(pte))
  		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