include/asm-generic/pgtable.h

#ifndef _ASM_GENERIC_PGTABLE_H
#define _ASM_GENERIC_PGTABLE_H

#ifndef __HAVE_ARCH_PTEP_ESTABLISH
/*
 * Establish a new mapping:
 *  - flush the old one
 *  - update the page tables
 *  - inform the TLB about the new one
 *
 * We hold the mm semaphore for reading and vma->vm_mm->page_table_lock.
 *
 * Note: the old pte is known to not be writable, so we don't need to
 * worry about dirty bits etc getting lost.
 */
#ifndef __HAVE_ARCH_SET_PTE_ATOMIC
#define ptep_establish(__vma, __address, __ptep, __entry)		\
do {				  					\
	set_pte(__ptep, __entry);					\
	flush_tlb_page(__vma, __address);				\
} while (0)
#else /* __HAVE_ARCH_SET_PTE_ATOMIC */
#define ptep_establish(__vma, __address, __ptep, __entry)		\
do {				  					\
	set_pte_atomic(__ptep, __entry);				\
	flush_tlb_page(__vma, __address);				\
} while (0)
#endif /* __HAVE_ARCH_SET_PTE_ATOMIC */
#endif

#ifndef __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
/*
 * Largely same as above, but 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.
 */
#define ptep_set_access_flags(__vma, __address, __ptep, __entry, __dirty) \
do {				  					  \
	set_pte(__ptep, __entry);					  \
	flush_tlb_page(__vma, __address);				  \
} while (0)
#endif

#ifndef __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
static inline int ptep_test_and_clear_young(pte_t *ptep)
{
	pte_t pte = *ptep;
	if (!pte_young(pte))
		return 0;
	set_pte(ptep, pte_mkold(pte));
	return 1;
}
#endif

#ifndef __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
#define ptep_clear_flush_young(__vma, __address, __ptep)		\
({									\
	int __young = ptep_test_and_clear_young(__ptep);		\
	if (__young)							\
		flush_tlb_page(__vma, __address);			\
	__young;							\
})
#endif

#ifndef __HAVE_ARCH_PTEP_TEST_AND_CLEAR_DIRTY
static inline int ptep_test_and_clear_dirty(pte_t *ptep)
{
	pte_t pte = *ptep;
	if (!pte_dirty(pte))
		return 0;
	set_pte(ptep, pte_mkclean(pte));
	return 1;
}
#endif

#ifndef __HAVE_ARCH_PTEP_CLEAR_DIRTY_FLUSH
#define ptep_clear_flush_dirty(__vma, __address, __ptep)		\
({									\
	int __dirty = ptep_test_and_clear_dirty(__ptep);		\
	if (__dirty)							\
		flush_tlb_page(__vma, __address);			\
	__dirty;							\
})
#endif

#ifndef __HAVE_ARCH_PTEP_GET_AND_CLEAR
static inline pte_t ptep_get_and_clear(pte_t *ptep)
{
	pte_t pte = *ptep;
	pte_clear(ptep);
	return pte;
}
#endif

#ifndef __HAVE_ARCH_PTEP_CLEAR_FLUSH
#define ptep_clear_flush(__vma, __address, __ptep)			\
({									\
	pte_t __pte = ptep_get_and_clear(__ptep);			\
	flush_tlb_page(__vma, __address);				\
	__pte;								\
})
#endif

#ifndef __HAVE_ARCH_PTEP_SET_WRPROTECT
static inline void ptep_set_wrprotect(pte_t *ptep)
{
	pte_t old_pte = *ptep;
	set_pte(ptep, pte_wrprotect(old_pte));
}
#endif

#ifndef __HAVE_ARCH_PTEP_MKDIRTY
static inline void ptep_mkdirty(pte_t *ptep)
{
	pte_t old_pte = *ptep;
	set_pte(ptep, pte_mkdirty(old_pte));
}
#endif

#ifndef __HAVE_ARCH_PTE_SAME
#define pte_same(A,B)	(pte_val(A) == pte_val(B))
#endif

#ifndef __HAVE_ARCH_PAGE_TEST_AND_CLEAR_DIRTY
#define page_test_and_clear_dirty(page) (0)
#endif

#ifndef __HAVE_ARCH_PAGE_TEST_AND_CLEAR_YOUNG
#define page_test_and_clear_young(page) (0)
#endif

#ifndef __HAVE_ARCH_PGD_OFFSET_GATE
#define pgd_offset_gate(mm, addr)	pgd_offset(mm, addr)
#endif

#endif /* _ASM_GENERIC_PGTABLE_H */