arch/arm/include/asm/pgtable-3level.h - kernel/mindspeed - Git at Google

 /*
  * arch/arm/include/asm/pgtable-3level.h
  *
  * Copyright (C) 2011 ARM Ltd.
  * Author: Catalin Marinas <catalin.marinas@arm.com>
  *
  * This program is free software; you can redistribute it and/or modify
  * it under the terms of the GNU General Public License version 2 as
  * published by the Free Software Foundation.
  *
  * This program is distributed in the hope that it will be useful,
  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  * GNU General Public License for more details.
  *
  * You should have received a copy of the GNU General Public License
  * along with this program; if not, write to the Free Software
  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
  */
 #ifndef _ASM_PGTABLE_3LEVEL_H
 #define _ASM_PGTABLE_3LEVEL_H

 /*
  * With LPAE, there are 3 levels of page tables. Each level has 512 entries of
  * 8 bytes each, occupying a 4K page. The first level table covers a range of
  * 512GB, each entry representing 1GB. Since we are limited to 4GB input
  * address range, only 4 entries in the PGD are used.
  *
  * There are enough spare bits in a page table entry for the kernel specific
  * state.
  */
 #define PTRS_PER_PTE		512
 #define PTRS_PER_PMD		512
 #define PTRS_PER_PGD		4

 #define PTE_HWTABLE_PTRS	(0)
 #define PTE_HWTABLE_OFF		(0)
 #define PTE_HWTABLE_SIZE	(PTRS_PER_PTE * sizeof(u64))

 /*
  * PGDIR_SHIFT determines the size a top-level page table entry can map.
  */
 #define PGDIR_SHIFT		30

 /*
  * PMD_SHIFT determines the size a middle-level page table entry can map.
  */
 #define PMD_SHIFT		21

 #define PMD_SIZE		(1UL << PMD_SHIFT)
 #define PMD_MASK		(~((1 << PMD_SHIFT) - 1))
 #define PGDIR_SIZE		(1UL << PGDIR_SHIFT)
 #define PGDIR_MASK		(~((1 << PGDIR_SHIFT) - 1))

 /*
  * section address mask and size definitions.
  */
 #define SECTION_SHIFT		21
 #define SECTION_SIZE		(1UL << SECTION_SHIFT)
 #define SECTION_MASK		(~((1 << SECTION_SHIFT) - 1))

 #define USER_PTRS_PER_PGD	(PAGE_OFFSET / PGDIR_SIZE)

 /*
  * Hugetlb definitions.
  */
 #define HPAGE_SHIFT		PMD_SHIFT
 #define HPAGE_SIZE		(_AC(1, UL) << HPAGE_SHIFT)
 #define HPAGE_MASK		(~(HPAGE_SIZE - 1))
 #define HUGETLB_PAGE_ORDER	(HPAGE_SHIFT - PAGE_SHIFT)

 /*
  * "Linux" PTE definitions for LPAE.
  *
  * These bits overlap with the hardware bits but the naming is preserved for
  * consistency with the classic page table format.
  */
 #define L_PTE_VALID		(_AT(pteval_t, 1) << 0)		/* Valid */
 #define L_PTE_PRESENT		(_AT(pteval_t, 3) << 0)		/* Present */
 #define L_PTE_USER		(_AT(pteval_t, 1) << 6)		/* AP[1] */
 #define L_PTE_SHARED		(_AT(pteval_t, 3) << 8)		/* SH[1:0], inner shareable */
 #define L_PTE_YOUNG		(_AT(pteval_t, 1) << 10)	/* AF */
 #define L_PTE_XN		(_AT(pteval_t, 1) << 54)	/* XN */
 #define L_PTE_DIRTY		(_AT(pteval_t, 1) << 55)
 #define L_PTE_SPECIAL		(_AT(pteval_t, 1) << 56)
 #define L_PTE_NONE		(_AT(pteval_t, 1) << 57)	/* PROT_NONE */
 #define L_PTE_RDONLY		(_AT(pteval_t, 1) << 58)	/* READ ONLY */

 #define L_PMD_SECT_VALID	(_AT(pmdval_t, 1) << 0)
 #define L_PMD_SECT_DIRTY	(_AT(pmdval_t, 1) << 55)
 #define L_PMD_SECT_SPLITTING	(_AT(pmdval_t, 1) << 56)
 #define L_PMD_SECT_NONE		(_AT(pmdval_t, 1) << 57)
 #define L_PMD_SECT_RDONLY	(_AT(pteval_t, 1) << 58)

 /*
  * To be used in assembly code with the upper page attributes.
  */
 #define L_PTE_XN_HIGH		(1 << (54 - 32))
 #define L_PTE_DIRTY_HIGH	(1 << (55 - 32))

 /*
  * AttrIndx[2:0] encoding (mapping attributes defined in the MAIR* registers).
  */
 #define L_PTE_MT_UNCACHED	(_AT(pteval_t, 0) << 2)	/* strongly ordered */
 #define L_PTE_MT_BUFFERABLE	(_AT(pteval_t, 1) << 2)	/* normal non-cacheable */
 #define L_PTE_MT_WRITETHROUGH	(_AT(pteval_t, 2) << 2)	/* normal inner write-through */
 #define L_PTE_MT_WRITEBACK	(_AT(pteval_t, 3) << 2)	/* normal inner write-back */
 #define L_PTE_MT_WRITEALLOC	(_AT(pteval_t, 7) << 2)	/* normal inner write-alloc */
 #define L_PTE_MT_DEV_SHARED	(_AT(pteval_t, 4) << 2)	/* device */
 #define L_PTE_MT_DEV_NONSHARED	(_AT(pteval_t, 4) << 2)	/* device */
 #define L_PTE_MT_DEV_WC		(_AT(pteval_t, 1) << 2)	/* normal non-cacheable */
 #define L_PTE_MT_DEV_CACHED	(_AT(pteval_t, 3) << 2)	/* normal inner write-back */
 #define L_PTE_MT_MASK		(_AT(pteval_t, 7) << 2)

 /*
  * Software PGD flags.
  */
 #define L_PGD_SWAPPER		(_AT(pgdval_t, 1) << 55)	/* swapper_pg_dir entry */

 /*
  * 2nd stage PTE definitions for LPAE.
  */
 #define L_PTE_S2_MT_UNCACHED		(_AT(pteval_t, 0x0) << 2) /* strongly ordered */
 #define L_PTE_S2_MT_WRITETHROUGH	(_AT(pteval_t, 0xa) << 2) /* normal inner write-through */
 #define L_PTE_S2_MT_WRITEBACK		(_AT(pteval_t, 0xf) << 2) /* normal inner write-back */
 #define L_PTE_S2_MT_DEV_SHARED		(_AT(pteval_t, 0x1) << 2) /* device */
 #define L_PTE_S2_MT_MASK		(_AT(pteval_t, 0xf) << 2)

 #define L_PTE_S2_RDONLY			(_AT(pteval_t, 1) << 6)   /* HAP[1]   */
 #define L_PTE_S2_RDWR			(_AT(pteval_t, 3) << 6)   /* HAP[2:1] */

 #define L_PMD_S2_RDONLY			(_AT(pmdval_t, 1) << 6)   /* HAP[1]   */
 #define L_PMD_S2_RDWR			(_AT(pmdval_t, 3) << 6)   /* HAP[2:1] */

 /*
  * Hyp-mode PL2 PTE definitions for LPAE.
  */
 #define L_PTE_HYP		L_PTE_USER

 #ifndef __ASSEMBLY__

 #define pud_none(pud)		(!pud_val(pud))
 #define pud_bad(pud)		(!(pud_val(pud) & 2))
 #define pud_present(pud)	(pud_val(pud))
 #define pmd_table(pmd)		((pmd_val(pmd) & PMD_TYPE_MASK) == \
 						 PMD_TYPE_TABLE)
 #define pmd_sect(pmd)		((pmd_val(pmd) & PMD_TYPE_MASK) == \
 						 PMD_TYPE_SECT)
 #define pmd_large(pmd)		pmd_sect(pmd)

 #define pud_clear(pudp)			\
 	do {				\
 		*pudp = __pud(0);	\
 		clean_pmd_entry(pudp);	\
 	} while (0)

 #define set_pud(pudp, pud)		\
 	do {				\
 		*pudp = pud;		\
 		flush_pmd_entry(pudp);	\
 	} while (0)

 static inline pmd_t *pud_page_vaddr(pud_t pud)
 {
 	return __va(pud_val(pud) & PHYS_MASK & (s32)PAGE_MASK);
 }

 /* Find an entry in the second-level page table.. */
 #define pmd_index(addr)		(((addr) >> PMD_SHIFT) & (PTRS_PER_PMD - 1))
 static inline pmd_t *pmd_offset(pud_t *pud, unsigned long addr)
 {
 	return (pmd_t *)pud_page_vaddr(*pud) + pmd_index(addr);
 }

 #define pmd_bad(pmd)		(!(pmd_val(pmd) & 2))

 #define copy_pmd(pmdpd,pmdps)		\
 	do {				\
 		*pmdpd = *pmdps;	\
 		flush_pmd_entry(pmdpd);	\
 	} while (0)

 #define pmd_clear(pmdp)			\
 	do {				\
 		*pmdp = __pmd(0);	\
 		clean_pmd_entry(pmdp);	\
 	} while (0)

 /*
  * For 3 levels of paging the PTE_EXT_NG bit will be set for user address ptes
  * that are written to a page table but not for ptes created with mk_pte.
  *
  * In hugetlb_no_page, a new huge pte (new_pte) is generated and passed to
  * hugetlb_cow, where it is compared with an entry in a page table.
  * This comparison test fails erroneously leading ultimately to a memory leak.
  *
  * To correct this behaviour, we mask off PTE_EXT_NG for any pte that is
  * present before running the comparison.
  */
 #define __HAVE_ARCH_PTE_SAME
 #define pte_same(pte_a,pte_b)	((pte_present(pte_a) ? pte_val(pte_a) & ~PTE_EXT_NG	\
 					: pte_val(pte_a))				\
 				== (pte_present(pte_b) ? pte_val(pte_b) & ~PTE_EXT_NG	\
 					: pte_val(pte_b)))

 #define set_pte_ext(ptep,pte,ext) cpu_set_pte_ext(ptep,__pte(pte_val(pte)|(ext)))

 #define pte_huge(pte)		(pte_val(pte) && !(pte_val(pte) & PTE_TABLE_BIT))
 #define pte_mkhuge(pte)		(__pte(pte_val(pte) & ~PTE_TABLE_BIT))

 #define pmd_isset(pmd, val)	((u32)(val) == (val) ? pmd_val(pmd) & (val) \
 						: !!(pmd_val(pmd) & (val)))
 #define pmd_isclear(pmd, val)	(!(pmd_val(pmd) & (val)))

 #define pmd_present(pmd)	(pmd_isset((pmd), L_PMD_SECT_VALID))
 #define pmd_young(pmd)		(pmd_isset((pmd), PMD_SECT_AF))
 #define pte_special(pte)	(pte_isset((pte), L_PTE_SPECIAL))
 static inline pte_t pte_mkspecial(pte_t pte)
 {
 	pte_val(pte) |= L_PTE_SPECIAL;
 	return pte;
 }
 #define	__HAVE_ARCH_PTE_SPECIAL

 #define __HAVE_ARCH_PMD_WRITE
 #define pmd_write(pmd)		(pmd_isclear((pmd), L_PMD_SECT_RDONLY))
 #define pmd_dirty(pmd)		(pmd_isset((pmd), L_PMD_SECT_DIRTY))
 #define pud_page(pud)		pmd_page(__pmd(pud_val(pud)))
 #define pud_write(pud)		pmd_write(__pmd(pud_val(pud)))

 #define pmd_hugewillfault(pmd)	(!pmd_young(pmd) || !pmd_write(pmd))
 #define pmd_thp_or_huge(pmd)	(pmd_huge(pmd) || pmd_trans_huge(pmd))

 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 #define pmd_trans_huge(pmd)	(pmd_val(pmd) && !pmd_table(pmd))
 #define pmd_trans_splitting(pmd) (pmd_isset((pmd), L_PMD_SECT_SPLITTING))

 #ifdef CONFIG_HAVE_RCU_TABLE_FREE
 #define __HAVE_ARCH_PMDP_SPLITTING_FLUSH
 void pmdp_splitting_flush(struct vm_area_struct *vma, unsigned long address,
 			  pmd_t *pmdp);
 #endif
 #endif

 #define PMD_BIT_FUNC(fn,op) \
 static inline pmd_t pmd_##fn(pmd_t pmd) { pmd_val(pmd) op; return pmd; }

 PMD_BIT_FUNC(wrprotect,	|= L_PMD_SECT_RDONLY);
 PMD_BIT_FUNC(mkold,	&= ~PMD_SECT_AF);
 PMD_BIT_FUNC(mksplitting, |= L_PMD_SECT_SPLITTING);
 PMD_BIT_FUNC(mkwrite,   &= ~L_PMD_SECT_RDONLY);
 PMD_BIT_FUNC(mkdirty,   |= L_PMD_SECT_DIRTY);
 PMD_BIT_FUNC(mkyoung,   |= PMD_SECT_AF);

 #define pmd_mkhuge(pmd)		(__pmd(pmd_val(pmd) & ~PMD_TABLE_BIT))

 #define pmd_pfn(pmd)		(((pmd_val(pmd) & PMD_MASK) & PHYS_MASK) >> PAGE_SHIFT)
 #define pfn_pmd(pfn,prot)	(__pmd(((phys_addr_t)(pfn) << PAGE_SHIFT) | pgprot_val(prot)))
 #define mk_pmd(page,prot)	pfn_pmd(page_to_pfn(page),prot)

 /* represent a notpresent pmd by faulting entry, this is used by pmdp_invalidate */
 static inline pmd_t pmd_mknotpresent(pmd_t pmd)
 {
 	return __pmd(pmd_val(pmd) & ~L_PMD_SECT_VALID);
 }

 static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot)
 {
 	const pmdval_t mask = PMD_SECT_USER | PMD_SECT_XN | L_PMD_SECT_RDONLY |
 				L_PMD_SECT_VALID | L_PMD_SECT_NONE;
 	pmd_val(pmd) = (pmd_val(pmd) & ~mask) | (pgprot_val(newprot) & mask);
 	return pmd;
 }

 static inline void set_pmd_at(struct mm_struct *mm, unsigned long addr,
 			      pmd_t *pmdp, pmd_t pmd)
 {
 	BUG_ON(addr >= TASK_SIZE);

 	/* create a faulting entry if PROT_NONE protected */
 	if (pmd_val(pmd) & L_PMD_SECT_NONE)
 		pmd_val(pmd) &= ~L_PMD_SECT_VALID;

 	if (pmd_write(pmd) && pmd_dirty(pmd))
 		pmd_val(pmd) &= ~PMD_SECT_AP2;
 	else
 		pmd_val(pmd) |= PMD_SECT_AP2;

 	*pmdp = __pmd(pmd_val(pmd) | PMD_SECT_nG);
 	flush_pmd_entry(pmdp);
 }

 static inline int has_transparent_hugepage(void)
 {
 	return 1;
 }

 #endif /* __ASSEMBLY__ */

 #endif /* _ASM_PGTABLE_3LEVEL_H */
	/*
	* arch/arm/include/asm/pgtable-3level.h
	*
	* Copyright (C) 2011 ARM Ltd.
	* Author: Catalin Marinas <catalin.marinas@arm.com>
	*
	* This program is free software; you can redistribute it and/or modify
	* it under the terms of the GNU General Public License version 2 as
	* published by the Free Software Foundation.
	*
	* This program is distributed in the hope that it will be useful,
	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
	* GNU General Public License for more details.
	*
	* You should have received a copy of the GNU General Public License
	* along with this program; if not, write to the Free Software
	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	*/
	#ifndef _ASM_PGTABLE_3LEVEL_H
	#define _ASM_PGTABLE_3LEVEL_H

	/*
	* With LPAE, there are 3 levels of page tables. Each level has 512 entries of
	* 8 bytes each, occupying a 4K page. The first level table covers a range of
	* 512GB, each entry representing 1GB. Since we are limited to 4GB input
	* address range, only 4 entries in the PGD are used.
	*
	* There are enough spare bits in a page table entry for the kernel specific
	* state.
	*/
	#define PTRS_PER_PTE 512
	#define PTRS_PER_PMD 512
	#define PTRS_PER_PGD 4

	#define PTE_HWTABLE_PTRS (0)
	#define PTE_HWTABLE_OFF (0)
	#define PTE_HWTABLE_SIZE (PTRS_PER_PTE * sizeof(u64))

	/*
	* PGDIR_SHIFT determines the size a top-level page table entry can map.
	*/
	#define PGDIR_SHIFT 30

	/*
	* PMD_SHIFT determines the size a middle-level page table entry can map.
	*/
	#define PMD_SHIFT 21

	#define PMD_SIZE (1UL << PMD_SHIFT)
	#define PMD_MASK (~((1 << PMD_SHIFT) - 1))
	#define PGDIR_SIZE (1UL << PGDIR_SHIFT)
	#define PGDIR_MASK (~((1 << PGDIR_SHIFT) - 1))

	/*
	* section address mask and size definitions.
	*/
	#define SECTION_SHIFT 21
	#define SECTION_SIZE (1UL << SECTION_SHIFT)
	#define SECTION_MASK (~((1 << SECTION_SHIFT) - 1))

	#define USER_PTRS_PER_PGD (PAGE_OFFSET / PGDIR_SIZE)

	/*
	* Hugetlb definitions.
	*/
	#define HPAGE_SHIFT PMD_SHIFT
	#define HPAGE_SIZE (_AC(1, UL) << HPAGE_SHIFT)
	#define HPAGE_MASK (~(HPAGE_SIZE - 1))
	#define HUGETLB_PAGE_ORDER (HPAGE_SHIFT - PAGE_SHIFT)

	/*
	* "Linux" PTE definitions for LPAE.
	*
	* These bits overlap with the hardware bits but the naming is preserved for
	* consistency with the classic page table format.
	*/
	#define L_PTE_VALID (_AT(pteval_t, 1) << 0) /* Valid */
	#define L_PTE_PRESENT (_AT(pteval_t, 3) << 0) /* Present */
	#define L_PTE_USER (_AT(pteval_t, 1) << 6) /* AP[1] */
	#define L_PTE_SHARED (_AT(pteval_t, 3) << 8) /* SH[1:0], inner shareable */
	#define L_PTE_YOUNG (_AT(pteval_t, 1) << 10) /* AF */
	#define L_PTE_XN (_AT(pteval_t, 1) << 54) /* XN */
	#define L_PTE_DIRTY (_AT(pteval_t, 1) << 55)
	#define L_PTE_SPECIAL (_AT(pteval_t, 1) << 56)
	#define L_PTE_NONE (_AT(pteval_t, 1) << 57) /* PROT_NONE */
	#define L_PTE_RDONLY (_AT(pteval_t, 1) << 58) /* READ ONLY */

	#define L_PMD_SECT_VALID (_AT(pmdval_t, 1) << 0)
	#define L_PMD_SECT_DIRTY (_AT(pmdval_t, 1) << 55)
	#define L_PMD_SECT_SPLITTING (_AT(pmdval_t, 1) << 56)
	#define L_PMD_SECT_NONE (_AT(pmdval_t, 1) << 57)
	#define L_PMD_SECT_RDONLY (_AT(pteval_t, 1) << 58)

	/*
	* To be used in assembly code with the upper page attributes.
	*/
	#define L_PTE_XN_HIGH (1 << (54 - 32))
	#define L_PTE_DIRTY_HIGH (1 << (55 - 32))

	/*
	* AttrIndx[2:0] encoding (mapping attributes defined in the MAIR* registers).
	*/
	#define L_PTE_MT_UNCACHED (_AT(pteval_t, 0) << 2) /* strongly ordered */
	#define L_PTE_MT_BUFFERABLE (_AT(pteval_t, 1) << 2) /* normal non-cacheable */
	#define L_PTE_MT_WRITETHROUGH (_AT(pteval_t, 2) << 2) /* normal inner write-through */
	#define L_PTE_MT_WRITEBACK (_AT(pteval_t, 3) << 2) /* normal inner write-back */
	#define L_PTE_MT_WRITEALLOC (_AT(pteval_t, 7) << 2) /* normal inner write-alloc */
	#define L_PTE_MT_DEV_SHARED (_AT(pteval_t, 4) << 2) /* device */
	#define L_PTE_MT_DEV_NONSHARED (_AT(pteval_t, 4) << 2) /* device */
	#define L_PTE_MT_DEV_WC (_AT(pteval_t, 1) << 2) /* normal non-cacheable */
	#define L_PTE_MT_DEV_CACHED (_AT(pteval_t, 3) << 2) /* normal inner write-back */
	#define L_PTE_MT_MASK (_AT(pteval_t, 7) << 2)

	/*
	* Software PGD flags.
	*/
	#define L_PGD_SWAPPER (_AT(pgdval_t, 1) << 55) /* swapper_pg_dir entry */

	/*
	* 2nd stage PTE definitions for LPAE.
	*/
	#define L_PTE_S2_MT_UNCACHED (_AT(pteval_t, 0x0) << 2) /* strongly ordered */
	#define L_PTE_S2_MT_WRITETHROUGH (_AT(pteval_t, 0xa) << 2) /* normal inner write-through */
	#define L_PTE_S2_MT_WRITEBACK (_AT(pteval_t, 0xf) << 2) /* normal inner write-back */
	#define L_PTE_S2_MT_DEV_SHARED (_AT(pteval_t, 0x1) << 2) /* device */
	#define L_PTE_S2_MT_MASK (_AT(pteval_t, 0xf) << 2)

	#define L_PTE_S2_RDONLY (_AT(pteval_t, 1) << 6) /* HAP[1] */
	#define L_PTE_S2_RDWR (_AT(pteval_t, 3) << 6) /* HAP[2:1] */

	#define L_PMD_S2_RDONLY (_AT(pmdval_t, 1) << 6) /* HAP[1] */
	#define L_PMD_S2_RDWR (_AT(pmdval_t, 3) << 6) /* HAP[2:1] */

	/*
	* Hyp-mode PL2 PTE definitions for LPAE.
	*/
	#define L_PTE_HYP L_PTE_USER

	#ifndef __ASSEMBLY__

	#define pud_none(pud) (!pud_val(pud))
	#define pud_bad(pud) (!(pud_val(pud) & 2))
	#define pud_present(pud) (pud_val(pud))
	#define pmd_table(pmd) ((pmd_val(pmd) & PMD_TYPE_MASK) == \
	PMD_TYPE_TABLE)
	#define pmd_sect(pmd) ((pmd_val(pmd) & PMD_TYPE_MASK) == \
	PMD_TYPE_SECT)
	#define pmd_large(pmd) pmd_sect(pmd)

	#define pud_clear(pudp) \
	do { \
	*pudp = __pud(0); \
	clean_pmd_entry(pudp); \
	} while (0)

	#define set_pud(pudp, pud) \
	do { \
	*pudp = pud; \
	flush_pmd_entry(pudp); \
	} while (0)

	static inline pmd_t *pud_page_vaddr(pud_t pud)
	{
	return __va(pud_val(pud) & PHYS_MASK & (s32)PAGE_MASK);
	}

	/* Find an entry in the second-level page table.. */
	#define pmd_index(addr) (((addr) >> PMD_SHIFT) & (PTRS_PER_PMD - 1))
	static inline pmd_t pmd_offset(pud_t pud, unsigned long addr)
	{
	return (pmd_t )pud_page_vaddr(pud) + pmd_index(addr);
	}

	#define pmd_bad(pmd) (!(pmd_val(pmd) & 2))

	#define copy_pmd(pmdpd,pmdps) \
	do { \
	pmdpd = pmdps; \
	flush_pmd_entry(pmdpd); \
	} while (0)

	#define pmd_clear(pmdp) \
	do { \
	*pmdp = __pmd(0); \
	clean_pmd_entry(pmdp); \
	} while (0)

	/*
	* For 3 levels of paging the PTE_EXT_NG bit will be set for user address ptes
	* that are written to a page table but not for ptes created with mk_pte.
	*
	* In hugetlb_no_page, a new huge pte (new_pte) is generated and passed to
	* hugetlb_cow, where it is compared with an entry in a page table.
	* This comparison test fails erroneously leading ultimately to a memory leak.
	*
	* To correct this behaviour, we mask off PTE_EXT_NG for any pte that is
	* present before running the comparison.
	*/
	#define __HAVE_ARCH_PTE_SAME
	#define pte_same(pte_a,pte_b) ((pte_present(pte_a) ? pte_val(pte_a) & ~PTE_EXT_NG \
	: pte_val(pte_a)) \
	== (pte_present(pte_b) ? pte_val(pte_b) & ~PTE_EXT_NG \
	: pte_val(pte_b)))

	#define set_pte_ext(ptep,pte,ext) cpu_set_pte_ext(ptep,__pte(pte_val(pte)\|(ext)))

	#define pte_huge(pte) (pte_val(pte) && !(pte_val(pte) & PTE_TABLE_BIT))
	#define pte_mkhuge(pte) (__pte(pte_val(pte) & ~PTE_TABLE_BIT))

	#define pmd_isset(pmd, val) ((u32)(val) == (val) ? pmd_val(pmd) & (val) \
	: !!(pmd_val(pmd) & (val)))
	#define pmd_isclear(pmd, val) (!(pmd_val(pmd) & (val)))

	#define pmd_present(pmd) (pmd_isset((pmd), L_PMD_SECT_VALID))
	#define pmd_young(pmd) (pmd_isset((pmd), PMD_SECT_AF))
	#define pte_special(pte) (pte_isset((pte), L_PTE_SPECIAL))
	static inline pte_t pte_mkspecial(pte_t pte)
	{
	pte_val(pte) \|= L_PTE_SPECIAL;
	return pte;
	}
	#define __HAVE_ARCH_PTE_SPECIAL

	#define __HAVE_ARCH_PMD_WRITE
	#define pmd_write(pmd) (pmd_isclear((pmd), L_PMD_SECT_RDONLY))
	#define pmd_dirty(pmd) (pmd_isset((pmd), L_PMD_SECT_DIRTY))
	#define pud_page(pud) pmd_page(__pmd(pud_val(pud)))
	#define pud_write(pud) pmd_write(__pmd(pud_val(pud)))

	#define pmd_hugewillfault(pmd) (!pmd_young(pmd) \|\| !pmd_write(pmd))
	#define pmd_thp_or_huge(pmd) (pmd_huge(pmd) \|\| pmd_trans_huge(pmd))

	#ifdef CONFIG_TRANSPARENT_HUGEPAGE
	#define pmd_trans_huge(pmd) (pmd_val(pmd) && !pmd_table(pmd))
	#define pmd_trans_splitting(pmd) (pmd_isset((pmd), L_PMD_SECT_SPLITTING))

	#ifdef CONFIG_HAVE_RCU_TABLE_FREE
	#define __HAVE_ARCH_PMDP_SPLITTING_FLUSH
	void pmdp_splitting_flush(struct vm_area_struct *vma, unsigned long address,
	pmd_t *pmdp);
	#endif
	#endif

	#define PMD_BIT_FUNC(fn,op) \
	static inline pmd_t pmd_##fn(pmd_t pmd) { pmd_val(pmd) op; return pmd; }

	PMD_BIT_FUNC(wrprotect, \|= L_PMD_SECT_RDONLY);
	PMD_BIT_FUNC(mkold, &= ~PMD_SECT_AF);
	PMD_BIT_FUNC(mksplitting, \|= L_PMD_SECT_SPLITTING);
	PMD_BIT_FUNC(mkwrite, &= ~L_PMD_SECT_RDONLY);
	PMD_BIT_FUNC(mkdirty, \|= L_PMD_SECT_DIRTY);
	PMD_BIT_FUNC(mkyoung, \|= PMD_SECT_AF);

	#define pmd_mkhuge(pmd) (__pmd(pmd_val(pmd) & ~PMD_TABLE_BIT))

	#define pmd_pfn(pmd) (((pmd_val(pmd) & PMD_MASK) & PHYS_MASK) >> PAGE_SHIFT)
	#define pfn_pmd(pfn,prot) (__pmd(((phys_addr_t)(pfn) << PAGE_SHIFT) \| pgprot_val(prot)))
	#define mk_pmd(page,prot) pfn_pmd(page_to_pfn(page),prot)

	/* represent a notpresent pmd by faulting entry, this is used by pmdp_invalidate */
	static inline pmd_t pmd_mknotpresent(pmd_t pmd)
	{
	return __pmd(pmd_val(pmd) & ~L_PMD_SECT_VALID);
	}

	static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot)
	{
	const pmdval_t mask = PMD_SECT_USER \| PMD_SECT_XN \| L_PMD_SECT_RDONLY \|
	L_PMD_SECT_VALID \| L_PMD_SECT_NONE;
	pmd_val(pmd) = (pmd_val(pmd) & ~mask) \| (pgprot_val(newprot) & mask);
	return pmd;
	}

	static inline void set_pmd_at(struct mm_struct *mm, unsigned long addr,
	pmd_t *pmdp, pmd_t pmd)
	{
	BUG_ON(addr >= TASK_SIZE);

	/* create a faulting entry if PROT_NONE protected */
	if (pmd_val(pmd) & L_PMD_SECT_NONE)
	pmd_val(pmd) &= ~L_PMD_SECT_VALID;

	if (pmd_write(pmd) && pmd_dirty(pmd))
	pmd_val(pmd) &= ~PMD_SECT_AP2;
	else
	pmd_val(pmd) \|= PMD_SECT_AP2;

	*pmdp = __pmd(pmd_val(pmd) \| PMD_SECT_nG);
	flush_pmd_entry(pmdp);
	}

	static inline int has_transparent_hugepage(void)
	{
	return 1;
	}

	#endif /* __ASSEMBLY__ */

	#endif /* _ASM_PGTABLE_3LEVEL_H */