arch/x86/include/asm/pgtable.h - kernel/msm-4.9 - Gitiles

 #ifndef _ASM_X86_PGTABLE_H
 #define _ASM_X86_PGTABLE_H

 #define FIRST_USER_ADDRESS	0

 #define _PAGE_BIT_PRESENT	0	/* is present */
 #define _PAGE_BIT_RW		1	/* writeable */
 #define _PAGE_BIT_USER		2	/* userspace addressable */
 #define _PAGE_BIT_PWT		3	/* page write through */
 #define _PAGE_BIT_PCD		4	/* page cache disabled */
 #define _PAGE_BIT_ACCESSED	5	/* was accessed (raised by CPU) */
 #define _PAGE_BIT_DIRTY		6	/* was written to (raised by CPU) */
 #define _PAGE_BIT_PSE		7	/* 4 MB (or 2MB) page */
 #define _PAGE_BIT_PAT		7	/* on 4KB pages */
 #define _PAGE_BIT_GLOBAL	8	/* Global TLB entry PPro+ */
 #define _PAGE_BIT_UNUSED1	9	/* available for programmer */
 #define _PAGE_BIT_IOMAP		10	/* flag used to indicate IO mapping */
 #define _PAGE_BIT_UNUSED3	11
 #define _PAGE_BIT_PAT_LARGE	12	/* On 2MB or 1GB pages */
 #define _PAGE_BIT_SPECIAL	_PAGE_BIT_UNUSED1
 #define _PAGE_BIT_CPA_TEST	_PAGE_BIT_UNUSED1
 #define _PAGE_BIT_NX           63       /* No execute: only valid after cpuid check */

 /* If _PAGE_BIT_PRESENT is clear, we use these: */
 /* - if the user mapped it with PROT_NONE; pte_present gives true */
 #define _PAGE_BIT_PROTNONE	_PAGE_BIT_GLOBAL
 /* - set: nonlinear file mapping, saved PTE; unset:swap */
 #define _PAGE_BIT_FILE		_PAGE_BIT_DIRTY

 #define _PAGE_PRESENT	(_AT(pteval_t, 1) << _PAGE_BIT_PRESENT)
 #define _PAGE_RW	(_AT(pteval_t, 1) << _PAGE_BIT_RW)
 #define _PAGE_USER	(_AT(pteval_t, 1) << _PAGE_BIT_USER)
 #define _PAGE_PWT	(_AT(pteval_t, 1) << _PAGE_BIT_PWT)
 #define _PAGE_PCD	(_AT(pteval_t, 1) << _PAGE_BIT_PCD)
 #define _PAGE_ACCESSED	(_AT(pteval_t, 1) << _PAGE_BIT_ACCESSED)
 #define _PAGE_DIRTY	(_AT(pteval_t, 1) << _PAGE_BIT_DIRTY)
 #define _PAGE_PSE	(_AT(pteval_t, 1) << _PAGE_BIT_PSE)
 #define _PAGE_GLOBAL	(_AT(pteval_t, 1) << _PAGE_BIT_GLOBAL)
 #define _PAGE_UNUSED1	(_AT(pteval_t, 1) << _PAGE_BIT_UNUSED1)
 #define _PAGE_IOMAP	(_AT(pteval_t, 1) << _PAGE_BIT_IOMAP)
 #define _PAGE_UNUSED3	(_AT(pteval_t, 1) << _PAGE_BIT_UNUSED3)
 #define _PAGE_PAT	(_AT(pteval_t, 1) << _PAGE_BIT_PAT)
 #define _PAGE_PAT_LARGE (_AT(pteval_t, 1) << _PAGE_BIT_PAT_LARGE)
 #define _PAGE_SPECIAL	(_AT(pteval_t, 1) << _PAGE_BIT_SPECIAL)
 #define _PAGE_CPA_TEST	(_AT(pteval_t, 1) << _PAGE_BIT_CPA_TEST)
 #define __HAVE_ARCH_PTE_SPECIAL

 #if defined(CONFIG_X86_64) || defined(CONFIG_X86_PAE)
 #define _PAGE_NX	(_AT(pteval_t, 1) << _PAGE_BIT_NX)
 #else
 #define _PAGE_NX	(_AT(pteval_t, 0))
 #endif

 #define _PAGE_FILE	(_AT(pteval_t, 1) << _PAGE_BIT_FILE)
 #define _PAGE_PROTNONE	(_AT(pteval_t, 1) << _PAGE_BIT_PROTNONE)

 #define _PAGE_TABLE	(_PAGE_PRESENT | _PAGE_RW | _PAGE_USER |	\
 			 _PAGE_ACCESSED | _PAGE_DIRTY)
 #define _KERNPG_TABLE	(_PAGE_PRESENT | _PAGE_RW | _PAGE_ACCESSED |	\
 			 _PAGE_DIRTY)

 /* Set of bits not changed in pte_modify */
 #define _PAGE_CHG_MASK	(PTE_PFN_MASK | _PAGE_PCD | _PAGE_PWT |		\
 			 _PAGE_SPECIAL | _PAGE_ACCESSED | _PAGE_DIRTY)

 #define _PAGE_CACHE_MASK	(_PAGE_PCD | _PAGE_PWT)
 #define _PAGE_CACHE_WB		(0)
 #define _PAGE_CACHE_WC		(_PAGE_PWT)
 #define _PAGE_CACHE_UC_MINUS	(_PAGE_PCD)
 #define _PAGE_CACHE_UC		(_PAGE_PCD | _PAGE_PWT)

 #define PAGE_NONE	__pgprot(_PAGE_PROTNONE | _PAGE_ACCESSED)
 #define PAGE_SHARED	__pgprot(_PAGE_PRESENT | _PAGE_RW | _PAGE_USER | \
 				 _PAGE_ACCESSED | _PAGE_NX)

 #define PAGE_SHARED_EXEC	__pgprot(_PAGE_PRESENT | _PAGE_RW |	\
 					 _PAGE_USER | _PAGE_ACCESSED)
 #define PAGE_COPY_NOEXEC	__pgprot(_PAGE_PRESENT | _PAGE_USER |	\
 					 _PAGE_ACCESSED | _PAGE_NX)
 #define PAGE_COPY_EXEC		__pgprot(_PAGE_PRESENT | _PAGE_USER |	\
 					 _PAGE_ACCESSED)
 #define PAGE_COPY		PAGE_COPY_NOEXEC
 #define PAGE_READONLY		__pgprot(_PAGE_PRESENT | _PAGE_USER |	\
 					 _PAGE_ACCESSED | _PAGE_NX)
 #define PAGE_READONLY_EXEC	__pgprot(_PAGE_PRESENT | _PAGE_USER |	\
 					 _PAGE_ACCESSED)

 #define __PAGE_KERNEL_EXEC						\
 	(_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY | _PAGE_ACCESSED | _PAGE_GLOBAL)
 #define __PAGE_KERNEL		(__PAGE_KERNEL_EXEC | _PAGE_NX)

 #define __PAGE_KERNEL_RO		(__PAGE_KERNEL & ~_PAGE_RW)
 #define __PAGE_KERNEL_RX		(__PAGE_KERNEL_EXEC & ~_PAGE_RW)
 #define __PAGE_KERNEL_EXEC_NOCACHE	(__PAGE_KERNEL_EXEC | _PAGE_PCD | _PAGE_PWT)
 #define __PAGE_KERNEL_WC		(__PAGE_KERNEL | _PAGE_CACHE_WC)
 #define __PAGE_KERNEL_NOCACHE		(__PAGE_KERNEL | _PAGE_PCD | _PAGE_PWT)
 #define __PAGE_KERNEL_UC_MINUS		(__PAGE_KERNEL | _PAGE_PCD)
 #define __PAGE_KERNEL_VSYSCALL		(__PAGE_KERNEL_RX | _PAGE_USER)
 #define __PAGE_KERNEL_VSYSCALL_NOCACHE	(__PAGE_KERNEL_VSYSCALL | _PAGE_PCD | _PAGE_PWT)
 #define __PAGE_KERNEL_LARGE		(__PAGE_KERNEL | _PAGE_PSE)
 #define __PAGE_KERNEL_LARGE_NOCACHE	(__PAGE_KERNEL | _PAGE_CACHE_UC | _PAGE_PSE)
 #define __PAGE_KERNEL_LARGE_EXEC	(__PAGE_KERNEL_EXEC | _PAGE_PSE)

 #define __PAGE_KERNEL_IO		(__PAGE_KERNEL | _PAGE_IOMAP)
 #define __PAGE_KERNEL_IO_NOCACHE	(__PAGE_KERNEL_NOCACHE | _PAGE_IOMAP)
 #define __PAGE_KERNEL_IO_UC_MINUS	(__PAGE_KERNEL_UC_MINUS | _PAGE_IOMAP)
 #define __PAGE_KERNEL_IO_WC		(__PAGE_KERNEL_WC | _PAGE_IOMAP)

 #define PAGE_KERNEL			__pgprot(__PAGE_KERNEL)
 #define PAGE_KERNEL_RO			__pgprot(__PAGE_KERNEL_RO)
 #define PAGE_KERNEL_EXEC		__pgprot(__PAGE_KERNEL_EXEC)
 #define PAGE_KERNEL_RX			__pgprot(__PAGE_KERNEL_RX)
 #define PAGE_KERNEL_WC			__pgprot(__PAGE_KERNEL_WC)
 #define PAGE_KERNEL_NOCACHE		__pgprot(__PAGE_KERNEL_NOCACHE)
 #define PAGE_KERNEL_UC_MINUS		__pgprot(__PAGE_KERNEL_UC_MINUS)
 #define PAGE_KERNEL_EXEC_NOCACHE	__pgprot(__PAGE_KERNEL_EXEC_NOCACHE)
 #define PAGE_KERNEL_LARGE		__pgprot(__PAGE_KERNEL_LARGE)
 #define PAGE_KERNEL_LARGE_NOCACHE	__pgprot(__PAGE_KERNEL_LARGE_NOCACHE)
 #define PAGE_KERNEL_LARGE_EXEC		__pgprot(__PAGE_KERNEL_LARGE_EXEC)
 #define PAGE_KERNEL_VSYSCALL		__pgprot(__PAGE_KERNEL_VSYSCALL)
 #define PAGE_KERNEL_VSYSCALL_NOCACHE	__pgprot(__PAGE_KERNEL_VSYSCALL_NOCACHE)

 #define PAGE_KERNEL_IO			__pgprot(__PAGE_KERNEL_IO)
 #define PAGE_KERNEL_IO_NOCACHE		__pgprot(__PAGE_KERNEL_IO_NOCACHE)
 #define PAGE_KERNEL_IO_UC_MINUS		__pgprot(__PAGE_KERNEL_IO_UC_MINUS)
 #define PAGE_KERNEL_IO_WC		__pgprot(__PAGE_KERNEL_IO_WC)

 /*         xwr */
 #define __P000	PAGE_NONE
 #define __P001	PAGE_READONLY
 #define __P010	PAGE_COPY
 #define __P011	PAGE_COPY
 #define __P100	PAGE_READONLY_EXEC
 #define __P101	PAGE_READONLY_EXEC
 #define __P110	PAGE_COPY_EXEC
 #define __P111	PAGE_COPY_EXEC

 #define __S000	PAGE_NONE
 #define __S001	PAGE_READONLY
 #define __S010	PAGE_SHARED
 #define __S011	PAGE_SHARED
 #define __S100	PAGE_READONLY_EXEC
 #define __S101	PAGE_READONLY_EXEC
 #define __S110	PAGE_SHARED_EXEC
 #define __S111	PAGE_SHARED_EXEC

 /*
  * early identity mapping  pte attrib macros.
  */
 #ifdef CONFIG_X86_64
 #define __PAGE_KERNEL_IDENT_LARGE_EXEC	__PAGE_KERNEL_LARGE_EXEC
 #else
 /*
  * For PDE_IDENT_ATTR include USER bit. As the PDE and PTE protection
  * bits are combined, this will alow user to access the high address mapped
  * VDSO in the presence of CONFIG_COMPAT_VDSO
  */
 #define PTE_IDENT_ATTR	 0x003		/* PRESENT+RW */
 #define PDE_IDENT_ATTR	 0x067		/* PRESENT+RW+USER+DIRTY+ACCESSED */
 #define PGD_IDENT_ATTR	 0x001		/* PRESENT (no other attributes) */
 #endif

 /*
  * Macro to mark a page protection value as UC-
  */
 #define pgprot_noncached(prot)					\
 	((boot_cpu_data.x86 > 3)				\
 	 ? (__pgprot(pgprot_val(prot) | _PAGE_CACHE_UC_MINUS))	\
 	 : (prot))

 #ifndef __ASSEMBLY__

 #define pgprot_writecombine	pgprot_writecombine
 extern pgprot_t pgprot_writecombine(pgprot_t prot);

 /*
  * ZERO_PAGE is a global shared page that is always zero: used
  * for zero-mapped memory areas etc..
  */
 extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)];
 #define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))

 extern spinlock_t pgd_lock;
 extern struct list_head pgd_list;

 /*
  * The following only work if pte_present() is true.
  * Undefined behaviour if not..
  */
 static inline int pte_dirty(pte_t pte)
 {
 	return pte_flags(pte) & _PAGE_DIRTY;
 }

 static inline int pte_young(pte_t pte)
 {
 	return pte_flags(pte) & _PAGE_ACCESSED;
 }

 static inline int pte_write(pte_t pte)
 {
 	return pte_flags(pte) & _PAGE_RW;
 }

 static inline int pte_file(pte_t pte)
 {
 	return pte_flags(pte) & _PAGE_FILE;
 }

 static inline int pte_huge(pte_t pte)
 {
 	return pte_flags(pte) & _PAGE_PSE;
 }

 static inline int pte_global(pte_t pte)
 {
 	return pte_flags(pte) & _PAGE_GLOBAL;
 }

 static inline int pte_exec(pte_t pte)
 {
 	return !(pte_flags(pte) & _PAGE_NX);
 }

 static inline int pte_special(pte_t pte)
 {
 	return pte_flags(pte) & _PAGE_SPECIAL;
 }

 static inline unsigned long pte_pfn(pte_t pte)
 {
 	return (pte_val(pte) & PTE_PFN_MASK) >> PAGE_SHIFT;
 }

 #define pte_page(pte)	pfn_to_page(pte_pfn(pte))

 static inline int pmd_large(pmd_t pte)
 {
 	return (pmd_val(pte) & (_PAGE_PSE | _PAGE_PRESENT)) ==
 		(_PAGE_PSE | _PAGE_PRESENT);
 }

 static inline pte_t pte_mkclean(pte_t pte)
 {
 	return __pte(pte_val(pte) & ~_PAGE_DIRTY);
 }

 static inline pte_t pte_mkold(pte_t pte)
 {
 	return __pte(pte_val(pte) & ~_PAGE_ACCESSED);
 }

 static inline pte_t pte_wrprotect(pte_t pte)
 {
 	return __pte(pte_val(pte) & ~_PAGE_RW);
 }

 static inline pte_t pte_mkexec(pte_t pte)
 {
 	return __pte(pte_val(pte) & ~_PAGE_NX);
 }

 static inline pte_t pte_mkdirty(pte_t pte)
 {
 	return __pte(pte_val(pte) | _PAGE_DIRTY);
 }

 static inline pte_t pte_mkyoung(pte_t pte)
 {
 	return __pte(pte_val(pte) | _PAGE_ACCESSED);
 }

 static inline pte_t pte_mkwrite(pte_t pte)
 {
 	return __pte(pte_val(pte) | _PAGE_RW);
 }

 static inline pte_t pte_mkhuge(pte_t pte)
 {
 	return __pte(pte_val(pte) | _PAGE_PSE);
 }

 static inline pte_t pte_clrhuge(pte_t pte)
 {
 	return __pte(pte_val(pte) & ~_PAGE_PSE);
 }

 static inline pte_t pte_mkglobal(pte_t pte)
 {
 	return __pte(pte_val(pte) | _PAGE_GLOBAL);
 }

 static inline pte_t pte_clrglobal(pte_t pte)
 {
 	return __pte(pte_val(pte) & ~_PAGE_GLOBAL);
 }

 static inline pte_t pte_mkspecial(pte_t pte)
 {
 	return __pte(pte_val(pte) | _PAGE_SPECIAL);
 }

 extern pteval_t __supported_pte_mask;

 static inline pte_t pfn_pte(unsigned long page_nr, pgprot_t pgprot)
 {
 	return __pte((((phys_addr_t)page_nr << PAGE_SHIFT) |
 		      pgprot_val(pgprot)) & __supported_pte_mask);
 }

 static inline pmd_t pfn_pmd(unsigned long page_nr, pgprot_t pgprot)
 {
 	return __pmd((((phys_addr_t)page_nr << PAGE_SHIFT) |
 		      pgprot_val(pgprot)) & __supported_pte_mask);
 }

 static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
 {
 	pteval_t val = pte_val(pte);

 	/*
 	 * Chop off the NX bit (if present), and add the NX portion of
 	 * the newprot (if present):
 	 */
 	val &= _PAGE_CHG_MASK;
 	val |= pgprot_val(newprot) & (~_PAGE_CHG_MASK) & __supported_pte_mask;

 	return __pte(val);
 }

 /* mprotect needs to preserve PAT bits when updating vm_page_prot */
 #define pgprot_modify pgprot_modify
 static inline pgprot_t pgprot_modify(pgprot_t oldprot, pgprot_t newprot)
 {
 	pgprotval_t preservebits = pgprot_val(oldprot) & _PAGE_CHG_MASK;
 	pgprotval_t addbits = pgprot_val(newprot);
 	return __pgprot(preservebits | addbits);
 }

 #define pte_pgprot(x) __pgprot(pte_flags(x) & PTE_FLAGS_MASK)

 #define canon_pgprot(p) __pgprot(pgprot_val(p) & __supported_pte_mask)

 #ifndef __ASSEMBLY__
 /* Indicate that x86 has its own track and untrack pfn vma functions */
 #define __HAVE_PFNMAP_TRACKING

 #define __HAVE_PHYS_MEM_ACCESS_PROT
 struct file;
 pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
                               unsigned long size, pgprot_t vma_prot);
 int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn,
                               unsigned long size, pgprot_t *vma_prot);
 #endif

 /* Install a pte for a particular vaddr in kernel space. */
 void set_pte_vaddr(unsigned long vaddr, pte_t pte);

 #ifdef CONFIG_X86_32
 extern void native_pagetable_setup_start(pgd_t *base);
 extern void native_pagetable_setup_done(pgd_t *base);
 #else
 static inline void native_pagetable_setup_start(pgd_t *base) {}
 static inline void native_pagetable_setup_done(pgd_t *base) {}
 #endif

 struct seq_file;
 extern void arch_report_meminfo(struct seq_file *m);

 #ifdef CONFIG_PARAVIRT
 #include <asm/paravirt.h>
 #else  /* !CONFIG_PARAVIRT */
 #define set_pte(ptep, pte)		native_set_pte(ptep, pte)
 #define set_pte_at(mm, addr, ptep, pte)	native_set_pte_at(mm, addr, ptep, pte)

 #define set_pte_present(mm, addr, ptep, pte)				\
 	native_set_pte_present(mm, addr, ptep, pte)
 #define set_pte_atomic(ptep, pte)					\
 	native_set_pte_atomic(ptep, pte)

 #define set_pmd(pmdp, pmd)		native_set_pmd(pmdp, pmd)

 #ifndef __PAGETABLE_PUD_FOLDED
 #define set_pgd(pgdp, pgd)		native_set_pgd(pgdp, pgd)
 #define pgd_clear(pgd)			native_pgd_clear(pgd)
 #endif

 #ifndef set_pud
 # define set_pud(pudp, pud)		native_set_pud(pudp, pud)
 #endif

 #ifndef __PAGETABLE_PMD_FOLDED
 #define pud_clear(pud)			native_pud_clear(pud)
 #endif

 #define pte_clear(mm, addr, ptep)	native_pte_clear(mm, addr, ptep)
 #define pmd_clear(pmd)			native_pmd_clear(pmd)

 #define pte_update(mm, addr, ptep)              do { } while (0)
 #define pte_update_defer(mm, addr, ptep)        do { } while (0)

 static inline void __init paravirt_pagetable_setup_start(pgd_t *base)
 {
 	native_pagetable_setup_start(base);
 }

 static inline void __init paravirt_pagetable_setup_done(pgd_t *base)
 {
 	native_pagetable_setup_done(base);
 }
 #endif	/* CONFIG_PARAVIRT */

 #endif	/* __ASSEMBLY__ */

 #ifdef CONFIG_X86_32
 # include "pgtable_32.h"
 #else
 # include "pgtable_64.h"
 #endif

 /*
  * the pgd page can be thought of an array like this: pgd_t[PTRS_PER_PGD]
  *
  * this macro returns the index of the entry in the pgd page which would
  * control the given virtual address
  */
 #define pgd_index(address) (((address) >> PGDIR_SHIFT) & (PTRS_PER_PGD - 1))

 /*
  * pgd_offset() returns a (pgd_t *)
  * pgd_index() is used get the offset into the pgd page's array of pgd_t's;
  */
 #define pgd_offset(mm, address) ((mm)->pgd + pgd_index((address)))
 /*
  * a shortcut which implies the use of the kernel's pgd, instead
  * of a process's
  */
 #define pgd_offset_k(address) pgd_offset(&init_mm, (address))


 #define KERNEL_PGD_BOUNDARY	pgd_index(PAGE_OFFSET)
 #define KERNEL_PGD_PTRS		(PTRS_PER_PGD - KERNEL_PGD_BOUNDARY)

 #ifndef __ASSEMBLY__

 enum {
 	PG_LEVEL_NONE,
 	PG_LEVEL_4K,
 	PG_LEVEL_2M,
 	PG_LEVEL_1G,
 	PG_LEVEL_NUM
 };

 #ifdef CONFIG_PROC_FS
 extern void update_page_count(int level, unsigned long pages);
 #else
 static inline void update_page_count(int level, unsigned long pages) { }
 #endif

 /*
  * Helper function that returns the kernel pagetable entry controlling
  * the virtual address 'address'. NULL means no pagetable entry present.
  * NOTE: the return type is pte_t but if the pmd is PSE then we return it
  * as a pte too.
  */
 extern pte_t *lookup_address(unsigned long address, unsigned int *level);

 /* local pte updates need not use xchg for locking */
 static inline pte_t native_local_ptep_get_and_clear(pte_t *ptep)
 {
 	pte_t res = *ptep;

 	/* Pure native function needs no input for mm, addr */
 	native_pte_clear(NULL, 0, ptep);
 	return res;
 }

 static inline void native_set_pte_at(struct mm_struct *mm, unsigned long addr,
 				     pte_t *ptep , pte_t pte)
 {
 	native_set_pte(ptep, pte);
 }

 #ifndef CONFIG_PARAVIRT
 /*
  * Rules for using pte_update - it must be called after any PTE update which
  * has not been done using the set_pte / clear_pte interfaces.  It is used by
  * shadow mode hypervisors to resynchronize the shadow page tables.  Kernel PTE
  * updates should either be sets, clears, or set_pte_atomic for P->P
  * transitions, which means this hook should only be called for user PTEs.
  * This hook implies a P->P protection or access change has taken place, which
  * requires a subsequent TLB flush.  The notification can optionally be delayed
  * until the TLB flush event by using the pte_update_defer form of the
  * interface, but care must be taken to assure that the flush happens while
  * still holding the same page table lock so that the shadow and primary pages
  * do not become out of sync on SMP.
  */
 #define pte_update(mm, addr, ptep)		do { } while (0)
 #define pte_update_defer(mm, addr, ptep)	do { } while (0)
 #endif

 /*
  * We only update the dirty/accessed state if we set
  * the dirty bit by hand in the kernel, since the hardware
  * will do the accessed bit for us, and we don't want to
  * race with other CPU's that might be updating the dirty
  * bit at the same time.
  */
 struct vm_area_struct;

 #define  __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
 extern int ptep_set_access_flags(struct vm_area_struct *vma,
 				 unsigned long address, pte_t *ptep,
 				 pte_t entry, int dirty);

 #define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
 extern int ptep_test_and_clear_young(struct vm_area_struct *vma,
 				     unsigned long addr, pte_t *ptep);

 #define __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
 extern int ptep_clear_flush_young(struct vm_area_struct *vma,
 				  unsigned long address, pte_t *ptep);

 #define __HAVE_ARCH_PTEP_GET_AND_CLEAR
 static inline pte_t ptep_get_and_clear(struct mm_struct *mm, unsigned long addr,
 				       pte_t *ptep)
 {
 	pte_t pte = native_ptep_get_and_clear(ptep);
 	pte_update(mm, addr, ptep);
 	return pte;
 }

 #define __HAVE_ARCH_PTEP_GET_AND_CLEAR_FULL
 static inline pte_t ptep_get_and_clear_full(struct mm_struct *mm,
 					    unsigned long addr, pte_t *ptep,
 					    int full)
 {
 	pte_t pte;
 	if (full) {
 		/*
 		 * Full address destruction in progress; paravirt does not
 		 * care about updates and native needs no locking
 		 */
 		pte = native_local_ptep_get_and_clear(ptep);
 	} else {
 		pte = ptep_get_and_clear(mm, addr, ptep);
 	}
 	return pte;
 }

 #define __HAVE_ARCH_PTEP_SET_WRPROTECT
 static inline void ptep_set_wrprotect(struct mm_struct *mm,
 				      unsigned long addr, pte_t *ptep)
 {
 	clear_bit(_PAGE_BIT_RW, (unsigned long *)&ptep->pte);
 	pte_update(mm, addr, ptep);
 }

 /*
  * clone_pgd_range(pgd_t *dst, pgd_t *src, int count);
  *
  *  dst - pointer to pgd range anwhere on a pgd page
  *  src - ""
  *  count - the number of pgds to copy.
  *
  * dst and src can be on the same page, but the range must not overlap,
  * and must not cross a page boundary.
  */
 static inline void clone_pgd_range(pgd_t *dst, pgd_t *src, int count)
 {
        memcpy(dst, src, count * sizeof(pgd_t));
 }


 #include <asm-generic/pgtable.h>
 #endif	/* __ASSEMBLY__ */

 #endif /* _ASM_X86_PGTABLE_H */
	#ifndef _ASM_X86_PGTABLE_H
	#define _ASM_X86_PGTABLE_H

	#define FIRST_USER_ADDRESS 0

	#define _PAGE_BIT_PRESENT 0 /* is present */
	#define _PAGE_BIT_RW 1 /* writeable */
	#define _PAGE_BIT_USER 2 /* userspace addressable */
	#define _PAGE_BIT_PWT 3 /* page write through */
	#define _PAGE_BIT_PCD 4 /* page cache disabled */
	#define _PAGE_BIT_ACCESSED 5 /* was accessed (raised by CPU) */
	#define _PAGE_BIT_DIRTY 6 /* was written to (raised by CPU) */
	#define _PAGE_BIT_PSE 7 /* 4 MB (or 2MB) page */
	#define _PAGE_BIT_PAT 7 /* on 4KB pages */
	#define _PAGE_BIT_GLOBAL 8 /* Global TLB entry PPro+ */
	#define _PAGE_BIT_UNUSED1 9 /* available for programmer */
	#define _PAGE_BIT_IOMAP 10 /* flag used to indicate IO mapping */
	#define _PAGE_BIT_UNUSED3 11
	#define _PAGE_BIT_PAT_LARGE 12 /* On 2MB or 1GB pages */
	#define _PAGE_BIT_SPECIAL _PAGE_BIT_UNUSED1
	#define _PAGE_BIT_CPA_TEST _PAGE_BIT_UNUSED1
	#define _PAGE_BIT_NX 63 /* No execute: only valid after cpuid check */

	/* If _PAGE_BIT_PRESENT is clear, we use these: */
	/* - if the user mapped it with PROT_NONE; pte_present gives true */
	#define _PAGE_BIT_PROTNONE _PAGE_BIT_GLOBAL
	/* - set: nonlinear file mapping, saved PTE; unset:swap */
	#define _PAGE_BIT_FILE _PAGE_BIT_DIRTY

	#define _PAGE_PRESENT (_AT(pteval_t, 1) << _PAGE_BIT_PRESENT)
	#define _PAGE_RW (_AT(pteval_t, 1) << _PAGE_BIT_RW)
	#define _PAGE_USER (_AT(pteval_t, 1) << _PAGE_BIT_USER)
	#define _PAGE_PWT (_AT(pteval_t, 1) << _PAGE_BIT_PWT)
	#define _PAGE_PCD (_AT(pteval_t, 1) << _PAGE_BIT_PCD)
	#define _PAGE_ACCESSED (_AT(pteval_t, 1) << _PAGE_BIT_ACCESSED)
	#define _PAGE_DIRTY (_AT(pteval_t, 1) << _PAGE_BIT_DIRTY)
	#define _PAGE_PSE (_AT(pteval_t, 1) << _PAGE_BIT_PSE)
	#define _PAGE_GLOBAL (_AT(pteval_t, 1) << _PAGE_BIT_GLOBAL)
	#define _PAGE_UNUSED1 (_AT(pteval_t, 1) << _PAGE_BIT_UNUSED1)
	#define _PAGE_IOMAP (_AT(pteval_t, 1) << _PAGE_BIT_IOMAP)
	#define _PAGE_UNUSED3 (_AT(pteval_t, 1) << _PAGE_BIT_UNUSED3)
	#define _PAGE_PAT (_AT(pteval_t, 1) << _PAGE_BIT_PAT)
	#define _PAGE_PAT_LARGE (_AT(pteval_t, 1) << _PAGE_BIT_PAT_LARGE)
	#define _PAGE_SPECIAL (_AT(pteval_t, 1) << _PAGE_BIT_SPECIAL)
	#define _PAGE_CPA_TEST (_AT(pteval_t, 1) << _PAGE_BIT_CPA_TEST)
	#define __HAVE_ARCH_PTE_SPECIAL

	#if defined(CONFIG_X86_64) \|\| defined(CONFIG_X86_PAE)
	#define _PAGE_NX (_AT(pteval_t, 1) << _PAGE_BIT_NX)
	#else
	#define _PAGE_NX (_AT(pteval_t, 0))
	#endif

	#define _PAGE_FILE (_AT(pteval_t, 1) << _PAGE_BIT_FILE)
	#define _PAGE_PROTNONE (_AT(pteval_t, 1) << _PAGE_BIT_PROTNONE)

	#define _PAGE_TABLE (_PAGE_PRESENT \| _PAGE_RW \| _PAGE_USER \| \
	_PAGE_ACCESSED \| _PAGE_DIRTY)
	#define _KERNPG_TABLE (_PAGE_PRESENT \| _PAGE_RW \| _PAGE_ACCESSED \| \
	_PAGE_DIRTY)

	/* Set of bits not changed in pte_modify */
	#define _PAGE_CHG_MASK (PTE_PFN_MASK \| _PAGE_PCD \| _PAGE_PWT \| \
	_PAGE_SPECIAL \| _PAGE_ACCESSED \| _PAGE_DIRTY)

	#define _PAGE_CACHE_MASK (_PAGE_PCD \| _PAGE_PWT)
	#define _PAGE_CACHE_WB (0)
	#define _PAGE_CACHE_WC (_PAGE_PWT)
	#define _PAGE_CACHE_UC_MINUS (_PAGE_PCD)
	#define _PAGE_CACHE_UC (_PAGE_PCD \| _PAGE_PWT)

	#define PAGE_NONE __pgprot(_PAGE_PROTNONE \| _PAGE_ACCESSED)
	#define PAGE_SHARED __pgprot(_PAGE_PRESENT \| _PAGE_RW \| _PAGE_USER \| \
	_PAGE_ACCESSED \| _PAGE_NX)

	#define PAGE_SHARED_EXEC __pgprot(_PAGE_PRESENT \| _PAGE_RW \| \
	_PAGE_USER \| _PAGE_ACCESSED)
	#define PAGE_COPY_NOEXEC __pgprot(_PAGE_PRESENT \| _PAGE_USER \| \
	_PAGE_ACCESSED \| _PAGE_NX)
	#define PAGE_COPY_EXEC __pgprot(_PAGE_PRESENT \| _PAGE_USER \| \
	_PAGE_ACCESSED)
	#define PAGE_COPY PAGE_COPY_NOEXEC
	#define PAGE_READONLY __pgprot(_PAGE_PRESENT \| _PAGE_USER \| \
	_PAGE_ACCESSED \| _PAGE_NX)
	#define PAGE_READONLY_EXEC __pgprot(_PAGE_PRESENT \| _PAGE_USER \| \
	_PAGE_ACCESSED)

	#define __PAGE_KERNEL_EXEC \
	(_PAGE_PRESENT \| _PAGE_RW \| _PAGE_DIRTY \| _PAGE_ACCESSED \| _PAGE_GLOBAL)
	#define __PAGE_KERNEL (__PAGE_KERNEL_EXEC \| _PAGE_NX)

	#define __PAGE_KERNEL_RO (__PAGE_KERNEL & ~_PAGE_RW)
	#define __PAGE_KERNEL_RX (__PAGE_KERNEL_EXEC & ~_PAGE_RW)
	#define __PAGE_KERNEL_EXEC_NOCACHE (__PAGE_KERNEL_EXEC \| _PAGE_PCD \| _PAGE_PWT)
	#define __PAGE_KERNEL_WC (__PAGE_KERNEL \| _PAGE_CACHE_WC)
	#define __PAGE_KERNEL_NOCACHE (__PAGE_KERNEL \| _PAGE_PCD \| _PAGE_PWT)
	#define __PAGE_KERNEL_UC_MINUS (__PAGE_KERNEL \| _PAGE_PCD)
	#define __PAGE_KERNEL_VSYSCALL (__PAGE_KERNEL_RX \| _PAGE_USER)
	#define __PAGE_KERNEL_VSYSCALL_NOCACHE (__PAGE_KERNEL_VSYSCALL \| _PAGE_PCD \| _PAGE_PWT)
	#define __PAGE_KERNEL_LARGE (__PAGE_KERNEL \| _PAGE_PSE)
	#define __PAGE_KERNEL_LARGE_NOCACHE (__PAGE_KERNEL \| _PAGE_CACHE_UC \| _PAGE_PSE)
	#define __PAGE_KERNEL_LARGE_EXEC (__PAGE_KERNEL_EXEC \| _PAGE_PSE)

	#define __PAGE_KERNEL_IO (__PAGE_KERNEL \| _PAGE_IOMAP)
	#define __PAGE_KERNEL_IO_NOCACHE (__PAGE_KERNEL_NOCACHE \| _PAGE_IOMAP)
	#define __PAGE_KERNEL_IO_UC_MINUS (__PAGE_KERNEL_UC_MINUS \| _PAGE_IOMAP)
	#define __PAGE_KERNEL_IO_WC (__PAGE_KERNEL_WC \| _PAGE_IOMAP)

	#define PAGE_KERNEL __pgprot(__PAGE_KERNEL)
	#define PAGE_KERNEL_RO __pgprot(__PAGE_KERNEL_RO)
	#define PAGE_KERNEL_EXEC __pgprot(__PAGE_KERNEL_EXEC)
	#define PAGE_KERNEL_RX __pgprot(__PAGE_KERNEL_RX)
	#define PAGE_KERNEL_WC __pgprot(__PAGE_KERNEL_WC)
	#define PAGE_KERNEL_NOCACHE __pgprot(__PAGE_KERNEL_NOCACHE)
	#define PAGE_KERNEL_UC_MINUS __pgprot(__PAGE_KERNEL_UC_MINUS)
	#define PAGE_KERNEL_EXEC_NOCACHE __pgprot(__PAGE_KERNEL_EXEC_NOCACHE)
	#define PAGE_KERNEL_LARGE __pgprot(__PAGE_KERNEL_LARGE)
	#define PAGE_KERNEL_LARGE_NOCACHE __pgprot(__PAGE_KERNEL_LARGE_NOCACHE)
	#define PAGE_KERNEL_LARGE_EXEC __pgprot(__PAGE_KERNEL_LARGE_EXEC)
	#define PAGE_KERNEL_VSYSCALL __pgprot(__PAGE_KERNEL_VSYSCALL)
	#define PAGE_KERNEL_VSYSCALL_NOCACHE __pgprot(__PAGE_KERNEL_VSYSCALL_NOCACHE)

	#define PAGE_KERNEL_IO __pgprot(__PAGE_KERNEL_IO)
	#define PAGE_KERNEL_IO_NOCACHE __pgprot(__PAGE_KERNEL_IO_NOCACHE)
	#define PAGE_KERNEL_IO_UC_MINUS __pgprot(__PAGE_KERNEL_IO_UC_MINUS)
	#define PAGE_KERNEL_IO_WC __pgprot(__PAGE_KERNEL_IO_WC)

	/* xwr */
	#define __P000 PAGE_NONE
	#define __P001 PAGE_READONLY
	#define __P010 PAGE_COPY
	#define __P011 PAGE_COPY
	#define __P100 PAGE_READONLY_EXEC
	#define __P101 PAGE_READONLY_EXEC
	#define __P110 PAGE_COPY_EXEC
	#define __P111 PAGE_COPY_EXEC

	#define __S000 PAGE_NONE
	#define __S001 PAGE_READONLY
	#define __S010 PAGE_SHARED
	#define __S011 PAGE_SHARED
	#define __S100 PAGE_READONLY_EXEC
	#define __S101 PAGE_READONLY_EXEC
	#define __S110 PAGE_SHARED_EXEC
	#define __S111 PAGE_SHARED_EXEC

	/*
	* early identity mapping pte attrib macros.
	*/
	#ifdef CONFIG_X86_64
	#define __PAGE_KERNEL_IDENT_LARGE_EXEC __PAGE_KERNEL_LARGE_EXEC
	#else
	/*
	* For PDE_IDENT_ATTR include USER bit. As the PDE and PTE protection
	* bits are combined, this will alow user to access the high address mapped
	* VDSO in the presence of CONFIG_COMPAT_VDSO
	*/
	#define PTE_IDENT_ATTR 0x003 /* PRESENT+RW */
	#define PDE_IDENT_ATTR 0x067 /* PRESENT+RW+USER+DIRTY+ACCESSED */
	#define PGD_IDENT_ATTR 0x001 /* PRESENT (no other attributes) */
	#endif

	/*
	* Macro to mark a page protection value as UC-
	*/
	#define pgprot_noncached(prot) \
	((boot_cpu_data.x86 > 3) \
	? (__pgprot(pgprot_val(prot) \| _PAGE_CACHE_UC_MINUS)) \
	: (prot))

	#ifndef __ASSEMBLY__

	#define pgprot_writecombine pgprot_writecombine
	extern pgprot_t pgprot_writecombine(pgprot_t prot);

	/*
	* ZERO_PAGE is a global shared page that is always zero: used
	* for zero-mapped memory areas etc..
	*/
	extern unsigned long empty_zero_page[PAGE_SIZE / sizeof(unsigned long)];
	#define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))

	extern spinlock_t pgd_lock;
	extern struct list_head pgd_list;

	/*
	* The following only work if pte_present() is true.
	* Undefined behaviour if not..
	*/
	static inline int pte_dirty(pte_t pte)
	{
	return pte_flags(pte) & _PAGE_DIRTY;
	}

	static inline int pte_young(pte_t pte)
	{
	return pte_flags(pte) & _PAGE_ACCESSED;
	}

	static inline int pte_write(pte_t pte)
	{
	return pte_flags(pte) & _PAGE_RW;
	}

	static inline int pte_file(pte_t pte)
	{
	return pte_flags(pte) & _PAGE_FILE;
	}

	static inline int pte_huge(pte_t pte)
	{
	return pte_flags(pte) & _PAGE_PSE;
	}

	static inline int pte_global(pte_t pte)
	{
	return pte_flags(pte) & _PAGE_GLOBAL;
	}

	static inline int pte_exec(pte_t pte)
	{
	return !(pte_flags(pte) & _PAGE_NX);
	}

	static inline int pte_special(pte_t pte)
	{
	return pte_flags(pte) & _PAGE_SPECIAL;
	}

	static inline unsigned long pte_pfn(pte_t pte)
	{
	return (pte_val(pte) & PTE_PFN_MASK) >> PAGE_SHIFT;
	}

	#define pte_page(pte) pfn_to_page(pte_pfn(pte))

	static inline int pmd_large(pmd_t pte)
	{
	return (pmd_val(pte) & (_PAGE_PSE \| _PAGE_PRESENT)) ==
	(_PAGE_PSE \| _PAGE_PRESENT);
	}

	static inline pte_t pte_mkclean(pte_t pte)
	{
	return __pte(pte_val(pte) & ~_PAGE_DIRTY);
	}

	static inline pte_t pte_mkold(pte_t pte)
	{
	return __pte(pte_val(pte) & ~_PAGE_ACCESSED);
	}

	static inline pte_t pte_wrprotect(pte_t pte)
	{
	return __pte(pte_val(pte) & ~_PAGE_RW);
	}

	static inline pte_t pte_mkexec(pte_t pte)
	{
	return __pte(pte_val(pte) & ~_PAGE_NX);
	}

	static inline pte_t pte_mkdirty(pte_t pte)
	{
	return __pte(pte_val(pte) \| _PAGE_DIRTY);
	}

	static inline pte_t pte_mkyoung(pte_t pte)
	{
	return __pte(pte_val(pte) \| _PAGE_ACCESSED);
	}

	static inline pte_t pte_mkwrite(pte_t pte)
	{
	return __pte(pte_val(pte) \| _PAGE_RW);
	}

	static inline pte_t pte_mkhuge(pte_t pte)
	{
	return __pte(pte_val(pte) \| _PAGE_PSE);
	}

	static inline pte_t pte_clrhuge(pte_t pte)
	{
	return __pte(pte_val(pte) & ~_PAGE_PSE);
	}

	static inline pte_t pte_mkglobal(pte_t pte)
	{
	return __pte(pte_val(pte) \| _PAGE_GLOBAL);
	}

	static inline pte_t pte_clrglobal(pte_t pte)
	{
	return __pte(pte_val(pte) & ~_PAGE_GLOBAL);
	}

	static inline pte_t pte_mkspecial(pte_t pte)
	{
	return __pte(pte_val(pte) \| _PAGE_SPECIAL);
	}

	extern pteval_t __supported_pte_mask;

	static inline pte_t pfn_pte(unsigned long page_nr, pgprot_t pgprot)
	{
	return __pte((((phys_addr_t)page_nr << PAGE_SHIFT) \|
	pgprot_val(pgprot)) & __supported_pte_mask);
	}

	static inline pmd_t pfn_pmd(unsigned long page_nr, pgprot_t pgprot)
	{
	return __pmd((((phys_addr_t)page_nr << PAGE_SHIFT) \|
	pgprot_val(pgprot)) & __supported_pte_mask);
	}

	static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
	{
	pteval_t val = pte_val(pte);

	/*
	* Chop off the NX bit (if present), and add the NX portion of
	* the newprot (if present):
	*/
	val &= _PAGE_CHG_MASK;
	val \|= pgprot_val(newprot) & (~_PAGE_CHG_MASK) & __supported_pte_mask;

	return __pte(val);
	}

	/* mprotect needs to preserve PAT bits when updating vm_page_prot */
	#define pgprot_modify pgprot_modify
	static inline pgprot_t pgprot_modify(pgprot_t oldprot, pgprot_t newprot)
	{
	pgprotval_t preservebits = pgprot_val(oldprot) & _PAGE_CHG_MASK;
	pgprotval_t addbits = pgprot_val(newprot);
	return __pgprot(preservebits \| addbits);
	}

	#define pte_pgprot(x) __pgprot(pte_flags(x) & PTE_FLAGS_MASK)

	#define canon_pgprot(p) __pgprot(pgprot_val(p) & __supported_pte_mask)

	#ifndef __ASSEMBLY__
	/* Indicate that x86 has its own track and untrack pfn vma functions */
	#define __HAVE_PFNMAP_TRACKING

	#define __HAVE_PHYS_MEM_ACCESS_PROT
	struct file;
	pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
	unsigned long size, pgprot_t vma_prot);
	int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn,
	unsigned long size, pgprot_t *vma_prot);
	#endif

	/* Install a pte for a particular vaddr in kernel space. */
	void set_pte_vaddr(unsigned long vaddr, pte_t pte);

	#ifdef CONFIG_X86_32
	extern void native_pagetable_setup_start(pgd_t *base);
	extern void native_pagetable_setup_done(pgd_t *base);
	#else
	static inline void native_pagetable_setup_start(pgd_t *base) {}
	static inline void native_pagetable_setup_done(pgd_t *base) {}
	#endif

	struct seq_file;
	extern void arch_report_meminfo(struct seq_file *m);

	#ifdef CONFIG_PARAVIRT
	#include <asm/paravirt.h>
	#else /* !CONFIG_PARAVIRT */
	#define set_pte(ptep, pte) native_set_pte(ptep, pte)
	#define set_pte_at(mm, addr, ptep, pte) native_set_pte_at(mm, addr, ptep, pte)

	#define set_pte_present(mm, addr, ptep, pte) \
	native_set_pte_present(mm, addr, ptep, pte)
	#define set_pte_atomic(ptep, pte) \
	native_set_pte_atomic(ptep, pte)

	#define set_pmd(pmdp, pmd) native_set_pmd(pmdp, pmd)

	#ifndef __PAGETABLE_PUD_FOLDED
	#define set_pgd(pgdp, pgd) native_set_pgd(pgdp, pgd)
	#define pgd_clear(pgd) native_pgd_clear(pgd)
	#endif

	#ifndef set_pud
	# define set_pud(pudp, pud) native_set_pud(pudp, pud)
	#endif

	#ifndef __PAGETABLE_PMD_FOLDED
	#define pud_clear(pud) native_pud_clear(pud)
	#endif

	#define pte_clear(mm, addr, ptep) native_pte_clear(mm, addr, ptep)
	#define pmd_clear(pmd) native_pmd_clear(pmd)

	#define pte_update(mm, addr, ptep) do { } while (0)
	#define pte_update_defer(mm, addr, ptep) do { } while (0)

	static inline void __init paravirt_pagetable_setup_start(pgd_t *base)
	{
	native_pagetable_setup_start(base);
	}

	static inline void __init paravirt_pagetable_setup_done(pgd_t *base)
	{
	native_pagetable_setup_done(base);
	}
	#endif /* CONFIG_PARAVIRT */

	#endif /* __ASSEMBLY__ */

	#ifdef CONFIG_X86_32
	# include "pgtable_32.h"
	#else
	# include "pgtable_64.h"
	#endif

	/*
	* the pgd page can be thought of an array like this: pgd_t[PTRS_PER_PGD]
	*
	* this macro returns the index of the entry in the pgd page which would
	* control the given virtual address
	*/
	#define pgd_index(address) (((address) >> PGDIR_SHIFT) & (PTRS_PER_PGD - 1))

	/*
	* pgd_offset() returns a (pgd_t *)
	* pgd_index() is used get the offset into the pgd page's array of pgd_t's;
	*/
	#define pgd_offset(mm, address) ((mm)->pgd + pgd_index((address)))
	/*
	* a shortcut which implies the use of the kernel's pgd, instead
	* of a process's
	*/
	#define pgd_offset_k(address) pgd_offset(&init_mm, (address))


	#define KERNEL_PGD_BOUNDARY pgd_index(PAGE_OFFSET)
	#define KERNEL_PGD_PTRS (PTRS_PER_PGD - KERNEL_PGD_BOUNDARY)

	#ifndef __ASSEMBLY__

	enum {
	PG_LEVEL_NONE,
	PG_LEVEL_4K,
	PG_LEVEL_2M,
	PG_LEVEL_1G,
	PG_LEVEL_NUM
	};

	#ifdef CONFIG_PROC_FS
	extern void update_page_count(int level, unsigned long pages);
	#else
	static inline void update_page_count(int level, unsigned long pages) { }
	#endif

	/*
	* Helper function that returns the kernel pagetable entry controlling
	* the virtual address 'address'. NULL means no pagetable entry present.
	* NOTE: the return type is pte_t but if the pmd is PSE then we return it
	* as a pte too.
	*/
	extern pte_t lookup_address(unsigned long address, unsigned int level);

	/* local pte updates need not use xchg for locking */
	static inline pte_t native_local_ptep_get_and_clear(pte_t *ptep)
	{
	pte_t res = *ptep;

	/* Pure native function needs no input for mm, addr */
	native_pte_clear(NULL, 0, ptep);
	return res;
	}

	static inline void native_set_pte_at(struct mm_struct *mm, unsigned long addr,
	pte_t *ptep , pte_t pte)
	{
	native_set_pte(ptep, pte);
	}

	#ifndef CONFIG_PARAVIRT
	/*
	* Rules for using pte_update - it must be called after any PTE update which
	* has not been done using the set_pte / clear_pte interfaces. It is used by
	* shadow mode hypervisors to resynchronize the shadow page tables. Kernel PTE
	* updates should either be sets, clears, or set_pte_atomic for P->P
	* transitions, which means this hook should only be called for user PTEs.
	* This hook implies a P->P protection or access change has taken place, which
	* requires a subsequent TLB flush. The notification can optionally be delayed
	* until the TLB flush event by using the pte_update_defer form of the
	* interface, but care must be taken to assure that the flush happens while
	* still holding the same page table lock so that the shadow and primary pages
	* do not become out of sync on SMP.
	*/
	#define pte_update(mm, addr, ptep) do { } while (0)
	#define pte_update_defer(mm, addr, ptep) do { } while (0)
	#endif

	/*
	* We only update the dirty/accessed state if we set
	* the dirty bit by hand in the kernel, since the hardware
	* will do the accessed bit for us, and we don't want to
	* race with other CPU's that might be updating the dirty
	* bit at the same time.
	*/
	struct vm_area_struct;

	#define __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
	extern int ptep_set_access_flags(struct vm_area_struct *vma,
	unsigned long address, pte_t *ptep,
	pte_t entry, int dirty);

	#define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
	extern int ptep_test_and_clear_young(struct vm_area_struct *vma,
	unsigned long addr, pte_t *ptep);

	#define __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
	extern int ptep_clear_flush_young(struct vm_area_struct *vma,
	unsigned long address, pte_t *ptep);

	#define __HAVE_ARCH_PTEP_GET_AND_CLEAR
	static inline pte_t ptep_get_and_clear(struct mm_struct *mm, unsigned long addr,
	pte_t *ptep)
	{
	pte_t pte = native_ptep_get_and_clear(ptep);
	pte_update(mm, addr, ptep);
	return pte;
	}

	#define __HAVE_ARCH_PTEP_GET_AND_CLEAR_FULL
	static inline pte_t ptep_get_and_clear_full(struct mm_struct *mm,
	unsigned long addr, pte_t *ptep,
	int full)
	{
	pte_t pte;
	if (full) {
	/*
	* Full address destruction in progress; paravirt does not
	* care about updates and native needs no locking
	*/
	pte = native_local_ptep_get_and_clear(ptep);
	} else {
	pte = ptep_get_and_clear(mm, addr, ptep);
	}
	return pte;
	}

	#define __HAVE_ARCH_PTEP_SET_WRPROTECT
	static inline void ptep_set_wrprotect(struct mm_struct *mm,
	unsigned long addr, pte_t *ptep)
	{
	clear_bit(_PAGE_BIT_RW, (unsigned long *)&ptep->pte);
	pte_update(mm, addr, ptep);
	}

	/*
	* clone_pgd_range(pgd_t dst, pgd_t src, int count);
	*
	* dst - pointer to pgd range anwhere on a pgd page
	* src - ""
	* count - the number of pgds to copy.
	*
	* dst and src can be on the same page, but the range must not overlap,
	* and must not cross a page boundary.
	*/
	static inline void clone_pgd_range(pgd_t dst, pgd_t src, int count)
	{
	memcpy(dst, src, count * sizeof(pgd_t));
	}


	#include <asm-generic/pgtable.h>
	#endif /* __ASSEMBLY__ */

	#endif /* _ASM_X86_PGTABLE_H */