[deliverable/linux.git] / include / asm-i386 / pgtable.h

#ifndef _I386_PGTABLE_H
#define _I386_PGTABLE_H


/*
 * The Linux memory management assumes a three-level page table setup. On
 * the i386, we use that, but "fold" the mid level into the top-level page
 * table, so that we physically have the same two-level page table as the
 * i386 mmu expects.
 *
 * This file contains the functions and defines necessary to modify and use
 * the i386 page table tree.
 */
#ifndef __ASSEMBLY__
#include <asm/processor.h>
#include <asm/fixmap.h>
#include <linux/threads.h>
#include <asm/paravirt.h>

#ifndef _I386_BITOPS_H
#include <asm/bitops.h>
#endif

#include <linux/slab.h>
#include <linux/list.h>
#include <linux/spinlock.h>

struct mm_struct;
struct vm_area_struct;

/*
 * ZERO_PAGE is a global shared page that is always zero: used
 * for zero-mapped memory areas etc..
 */
#define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
extern unsigned long empty_zero_page[1024];
extern pgd_t swapper_pg_dir[1024];
extern kmem_cache_t *pgd_cache;
extern kmem_cache_t *pmd_cache;
extern spinlock_t pgd_lock;
extern struct page *pgd_list;

void pmd_ctor(void *, kmem_cache_t *, unsigned long);
void pgd_ctor(void *, kmem_cache_t *, unsigned long);
void pgd_dtor(void *, kmem_cache_t *, unsigned long);
void pgtable_cache_init(void);
void paging_init(void);

/*
 * The Linux x86 paging architecture is 'compile-time dual-mode', it
 * implements both the traditional 2-level x86 page tables and the
 * newer 3-level PAE-mode page tables.
 */
#ifdef CONFIG_X86_PAE
# include <asm/pgtable-3level-defs.h>
# define PMD_SIZE	(1UL << PMD_SHIFT)
# define PMD_MASK	(~(PMD_SIZE-1))
#else
# include <asm/pgtable-2level-defs.h>
#endif

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

#define USER_PTRS_PER_PGD	(TASK_SIZE/PGDIR_SIZE)
#define FIRST_USER_ADDRESS	0

#define USER_PGD_PTRS (PAGE_OFFSET >> PGDIR_SHIFT)
#define KERNEL_PGD_PTRS (PTRS_PER_PGD-USER_PGD_PTRS)

#define TWOLEVEL_PGDIR_SHIFT	22
#define BOOT_USER_PGD_PTRS (__PAGE_OFFSET >> TWOLEVEL_PGDIR_SHIFT)
#define BOOT_KERNEL_PGD_PTRS (1024-BOOT_USER_PGD_PTRS)

/* Just any arbitrary offset to the start of the vmalloc VM area: the
 * current 8MB value just means that there will be a 8MB "hole" after the
 * physical memory until the kernel virtual memory starts.  That means that
 * any out-of-bounds memory accesses will hopefully be caught.
 * The vmalloc() routines leaves a hole of 4kB between each vmalloced
 * area for the same reason. ;)
 */
#define VMALLOC_OFFSET	(8*1024*1024)
#define VMALLOC_START	(((unsigned long) high_memory + vmalloc_earlyreserve + \
			2*VMALLOC_OFFSET-1) & ~(VMALLOC_OFFSET-1))
#ifdef CONFIG_HIGHMEM
# define VMALLOC_END	(PKMAP_BASE-2*PAGE_SIZE)
#else
# define VMALLOC_END	(FIXADDR_START-2*PAGE_SIZE)
#endif

/*
 * _PAGE_PSE set in the page directory entry just means that
 * the page directory entry points directly to a 4MB-aligned block of
 * memory. 
 */
#define _PAGE_BIT_PRESENT	0
#define _PAGE_BIT_RW		1
#define _PAGE_BIT_USER		2
#define _PAGE_BIT_PWT		3
#define _PAGE_BIT_PCD		4
#define _PAGE_BIT_ACCESSED	5
#define _PAGE_BIT_DIRTY		6
#define _PAGE_BIT_PSE		7	/* 4 MB (or 2MB) page, Pentium+, if present.. */
#define _PAGE_BIT_GLOBAL	8	/* Global TLB entry PPro+ */
#define _PAGE_BIT_UNUSED1	9	/* available for programmer */
#define _PAGE_BIT_UNUSED2	10
#define _PAGE_BIT_UNUSED3	11
#define _PAGE_BIT_NX		63

#define _PAGE_PRESENT	0x001
#define _PAGE_RW	0x002
#define _PAGE_USER	0x004
#define _PAGE_PWT	0x008
#define _PAGE_PCD	0x010
#define _PAGE_ACCESSED	0x020
#define _PAGE_DIRTY	0x040
#define _PAGE_PSE	0x080	/* 4 MB (or 2MB) page, Pentium+, if present.. */
#define _PAGE_GLOBAL	0x100	/* Global TLB entry PPro+ */
#define _PAGE_UNUSED1	0x200	/* available for programmer */
#define _PAGE_UNUSED2	0x400
#define _PAGE_UNUSED3	0x800

/* If _PAGE_PRESENT is clear, we use these: */
#define _PAGE_FILE	0x040	/* nonlinear file mapping, saved PTE; unset:swap */
#define _PAGE_PROTNONE	0x080	/* if the user mapped it with PROT_NONE;
				   pte_present gives true */
#ifdef CONFIG_X86_PAE
#define _PAGE_NX	(1ULL<<_PAGE_BIT_NX)
#else
#define _PAGE_NX	0
#endif

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

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

#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 \
	(_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY | _PAGE_ACCESSED | _PAGE_NX)
#define _PAGE_KERNEL_EXEC \
	(_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY | _PAGE_ACCESSED)

extern unsigned long long __PAGE_KERNEL, __PAGE_KERNEL_EXEC;
#define __PAGE_KERNEL_RO		(__PAGE_KERNEL & ~_PAGE_RW)
#define __PAGE_KERNEL_NOCACHE		(__PAGE_KERNEL | _PAGE_PCD)
#define __PAGE_KERNEL_LARGE		(__PAGE_KERNEL | _PAGE_PSE)
#define __PAGE_KERNEL_LARGE_EXEC	(__PAGE_KERNEL_EXEC | _PAGE_PSE)

#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_NOCACHE	__pgprot(__PAGE_KERNEL_NOCACHE)
#define PAGE_KERNEL_LARGE	__pgprot(__PAGE_KERNEL_LARGE)
#define PAGE_KERNEL_LARGE_EXEC	__pgprot(__PAGE_KERNEL_LARGE_EXEC)

/*
 * The i386 can't do page protection for execute, and considers that
 * the same are read. Also, write permissions imply read permissions.
 * This is the closest we can get..
 */
#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

/*
 * Define this if things work differently on an i386 and an i486:
 * it will (on an i486) warn about kernel memory accesses that are
 * done without a 'access_ok(VERIFY_WRITE,..)'
 */
#undef TEST_ACCESS_OK

/* The boot page tables (all created as a single array) */
extern unsigned long pg0[];

#define pte_present(x)	((x).pte_low & (_PAGE_PRESENT | _PAGE_PROTNONE))

/* To avoid harmful races, pmd_none(x) should check only the lower when PAE */
#define pmd_none(x)	(!(unsigned long)pmd_val(x))
#define pmd_present(x)	(pmd_val(x) & _PAGE_PRESENT)
#define	pmd_bad(x)	((pmd_val(x) & (~PAGE_MASK & ~_PAGE_USER)) != _KERNPG_TABLE)


#define pages_to_mb(x) ((x) >> (20-PAGE_SHIFT))

/*
 * The following only work if pte_present() is true.
 * Undefined behaviour if not..
 */
static inline int pte_user(pte_t pte)		{ return (pte).pte_low & _PAGE_USER; }
static inline int pte_read(pte_t pte)		{ return (pte).pte_low & _PAGE_USER; }
static inline int pte_dirty(pte_t pte)		{ return (pte).pte_low & _PAGE_DIRTY; }
static inline int pte_young(pte_t pte)		{ return (pte).pte_low & _PAGE_ACCESSED; }
static inline int pte_write(pte_t pte)		{ return (pte).pte_low & _PAGE_RW; }
static inline int pte_huge(pte_t pte)		{ return (pte).pte_low & _PAGE_PSE; }

/*
 * The following only works if pte_present() is not true.
 */
static inline int pte_file(pte_t pte)		{ return (pte).pte_low & _PAGE_FILE; }

static inline pte_t pte_rdprotect(pte_t pte)	{ (pte).pte_low &= ~_PAGE_USER; return pte; }
static inline pte_t pte_exprotect(pte_t pte)	{ (pte).pte_low &= ~_PAGE_USER; return pte; }
static inline pte_t pte_mkclean(pte_t pte)	{ (pte).pte_low &= ~_PAGE_DIRTY; return pte; }
static inline pte_t pte_mkold(pte_t pte)	{ (pte).pte_low &= ~_PAGE_ACCESSED; return pte; }
static inline pte_t pte_wrprotect(pte_t pte)	{ (pte).pte_low &= ~_PAGE_RW; return pte; }
static inline pte_t pte_mkread(pte_t pte)	{ (pte).pte_low |= _PAGE_USER; return pte; }
static inline pte_t pte_mkexec(pte_t pte)	{ (pte).pte_low |= _PAGE_USER; return pte; }
static inline pte_t pte_mkdirty(pte_t pte)	{ (pte).pte_low |= _PAGE_DIRTY; return pte; }
static inline pte_t pte_mkyoung(pte_t pte)	{ (pte).pte_low |= _PAGE_ACCESSED; return pte; }
static inline pte_t pte_mkwrite(pte_t pte)	{ (pte).pte_low |= _PAGE_RW; return pte; }
static inline pte_t pte_mkhuge(pte_t pte)	{ (pte).pte_low |= _PAGE_PSE; return pte; }

#ifdef CONFIG_X86_PAE
# include <asm/pgtable-3level.h>
#else
# include <asm/pgtable-2level.h>
#endif

#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.
 */
#define  __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
#define ptep_set_access_flags(vma, address, ptep, entry, dirty)		\
do {									\
	if (dirty) {							\
		(ptep)->pte_low = (entry).pte_low;			\
		pte_update_defer((vma)->vm_mm, (addr), (ptep));		\
		flush_tlb_page(vma, address);				\
	}								\
} while (0)

/*
 * We don't actually have these, but we want to advertise them so that
 * we can encompass the flush here.
 */
#define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_DIRTY
#define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG

/*
 * Rules for using ptep_establish: the pte MUST be a user pte, and
 * must be a present->present transition.
 */
#define __HAVE_ARCH_PTEP_ESTABLISH
#define ptep_establish(vma, address, ptep, pteval)			\
do {									\
	set_pte_present((vma)->vm_mm, address, ptep, pteval);		\
	flush_tlb_page(vma, address);					\
} while (0)

#define __HAVE_ARCH_PTEP_CLEAR_DIRTY_FLUSH
#define ptep_clear_flush_dirty(vma, address, ptep)			\
({									\
	int __dirty;							\
	__dirty = pte_dirty(*(ptep));					\
	if (__dirty) {							\
		clear_bit(_PAGE_BIT_DIRTY, &(ptep)->pte_low);		\
		pte_update_defer((vma)->vm_mm, (addr), (ptep));		\
		flush_tlb_page(vma, address);				\
	}								\
	__dirty;							\
})

#define __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
#define ptep_clear_flush_young(vma, address, ptep)			\
({									\
	int __young;							\
	__young = pte_young(*(ptep));					\
	if (__young) {							\
		clear_bit(_PAGE_BIT_ACCESSED, &(ptep)->pte_low);	\
		pte_update_defer((vma)->vm_mm, (addr), (ptep));		\
		flush_tlb_page(vma, address);				\
	}								\
	__young;							\
})

#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) {
		pte = *ptep;
		pte_clear(mm, addr, 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, &ptep->pte_low);
	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));
}

/*
 * Macro to mark a page protection value as "uncacheable".  On processors which do not support
 * it, this is a no-op.
 */
#define pgprot_noncached(prot)	((boot_cpu_data.x86 > 3)					  \
				 ? (__pgprot(pgprot_val(prot) | _PAGE_PCD | _PAGE_PWT)) : (prot))

/*
 * Conversion functions: convert a page and protection to a page entry,
 * and a page entry and page directory to the page they refer to.
 */

#define mk_pte(page, pgprot)	pfn_pte(page_to_pfn(page), (pgprot))

static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
{
	pte.pte_low &= _PAGE_CHG_MASK;
	pte.pte_low |= pgprot_val(newprot);
#ifdef CONFIG_X86_PAE
	/*
	 * Chop off the NX bit (if present), and add the NX portion of
	 * the newprot (if present):
	 */
	pte.pte_high &= ~(1 << (_PAGE_BIT_NX - 32));
	pte.pte_high |= (pgprot_val(newprot) >> 32) & \
					(__supported_pte_mask >> 32);
#endif
	return pte;
}

#define pmd_large(pmd) \
((pmd_val(pmd) & (_PAGE_PSE|_PAGE_PRESENT)) == (_PAGE_PSE|_PAGE_PRESENT))

/*
 * 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))
#define pgd_index_k(addr) pgd_index(addr)

/*
 * 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)

/*
 * the pmd page can be thought of an array like this: pmd_t[PTRS_PER_PMD]
 *
 * this macro returns the index of the entry in the pmd page which would
 * control the given virtual address
 */
#define pmd_index(address) \
		(((address) >> PMD_SHIFT) & (PTRS_PER_PMD-1))

/*
 * the pte page can be thought of an array like this: pte_t[PTRS_PER_PTE]
 *
 * this macro returns the index of the entry in the pte page which would
 * control the given virtual address
 */
#define pte_index(address) \
		(((address) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
#define pte_offset_kernel(dir, address) \
	((pte_t *) pmd_page_vaddr(*(dir)) +  pte_index(address))

#define pmd_page(pmd) (pfn_to_page(pmd_val(pmd) >> PAGE_SHIFT))

#define pmd_page_vaddr(pmd) \
		((unsigned long) __va(pmd_val(pmd) & PAGE_MASK))

/*
 * 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);

/*
 * Make a given kernel text page executable/non-executable.
 * Returns the previous executability setting of that page (which
 * is used to restore the previous state). Used by the SMP bootup code.
 * NOTE: this is an __init function for security reasons.
 */
#ifdef CONFIG_X86_PAE
 extern int set_kernel_exec(unsigned long vaddr, int enable);
#else
 static inline int set_kernel_exec(unsigned long vaddr, int enable) { return 0;}
#endif

#if defined(CONFIG_HIGHPTE)
#define pte_offset_map(dir, address) \
	((pte_t *)kmap_atomic(pmd_page(*(dir)),KM_PTE0) + pte_index(address))
#define pte_offset_map_nested(dir, address) \
	((pte_t *)kmap_atomic(pmd_page(*(dir)),KM_PTE1) + pte_index(address))
#define pte_unmap(pte) kunmap_atomic(pte, KM_PTE0)
#define pte_unmap_nested(pte) kunmap_atomic(pte, KM_PTE1)
#else
#define pte_offset_map(dir, address) \
	((pte_t *)page_address(pmd_page(*(dir))) + pte_index(address))
#define pte_offset_map_nested(dir, address) pte_offset_map(dir, address)
#define pte_unmap(pte) do { } while (0)
#define pte_unmap_nested(pte) do { } while (0)
#endif

/* Clear a kernel PTE and flush it from the TLB */
#define kpte_clear_flush(ptep, vaddr)					\
do {									\
	pte_clear(&init_mm, vaddr, ptep);				\
	__flush_tlb_one(vaddr);						\
} while (0)

/*
 * The i386 doesn't have any external MMU info: the kernel page
 * tables contain all the necessary information.
 */
#define update_mmu_cache(vma,address,pte) do { } while (0)
#endif /* !__ASSEMBLY__ */

#ifdef CONFIG_FLATMEM
#define kern_addr_valid(addr)	(1)
#endif /* CONFIG_FLATMEM */

#define io_remap_pfn_range(vma, vaddr, pfn, size, prot)		\
		remap_pfn_range(vma, vaddr, pfn, size, prot)

#define MK_IOSPACE_PFN(space, pfn)	(pfn)
#define GET_IOSPACE(pfn)		0
#define GET_PFN(pfn)			(pfn)

#include <asm-generic/pgtable.h>

#endif /* _I386_PGTABLE_H */
Commit	Line	Data
1da177e4 LT	1	#ifndef _I386_PGTABLE_H
	2	#define _I386_PGTABLE_H
	3
1da177e4 LT	4
	5	/*
	6	* The Linux memory management assumes a three-level page table setup. On
	7	* the i386, we use that, but "fold" the mid level into the top-level page
	8	* table, so that we physically have the same two-level page table as the
	9	* i386 mmu expects.
	10	*
	11	* This file contains the functions and defines necessary to modify and use
	12	* the i386 page table tree.
	13	*/
	14	#ifndef __ASSEMBLY__
	15	#include <asm/processor.h>
	16	#include <asm/fixmap.h>
	17	#include <linux/threads.h>
da181a8b	18	#include <asm/paravirt.h>
1da177e4 LT	19
	20	#ifndef _I386_BITOPS_H
	21	#include <asm/bitops.h>
	22	#endif
	23
	24	#include <linux/slab.h>
	25	#include <linux/list.h>
	26	#include <linux/spinlock.h>
	27
8c65b4a6 TS	28	struct mm_struct;
	29	struct vm_area_struct;
	30
1da177e4 LT	31	/*
	32	* ZERO_PAGE is a global shared page that is always zero: used
	33	* for zero-mapped memory areas etc..
	34	*/
	35	#define ZERO_PAGE(vaddr) (virt_to_page(empty_zero_page))
	36	extern unsigned long empty_zero_page[1024];
	37	extern pgd_t swapper_pg_dir[1024];
	38	extern kmem_cache_t *pgd_cache;
	39	extern kmem_cache_t *pmd_cache;
	40	extern spinlock_t pgd_lock;
	41	extern struct page *pgd_list;
	42
	43	void pmd_ctor(void , kmem_cache_t , unsigned long);
	44	void pgd_ctor(void , kmem_cache_t , unsigned long);
	45	void pgd_dtor(void , kmem_cache_t , unsigned long);
	46	void pgtable_cache_init(void);
	47	void paging_init(void);
	48
	49	/*
	50	* The Linux x86 paging architecture is 'compile-time dual-mode', it
	51	* implements both the traditional 2-level x86 page tables and the
	52	* newer 3-level PAE-mode page tables.
	53	*/
	54	#ifdef CONFIG_X86_PAE
	55	# include <asm/pgtable-3level-defs.h>
	56	# define PMD_SIZE (1UL << PMD_SHIFT)
	57	# define PMD_MASK (~(PMD_SIZE-1))
	58	#else
	59	# include <asm/pgtable-2level-defs.h>
	60	#endif
	61
	62	#define PGDIR_SIZE (1UL << PGDIR_SHIFT)
	63	#define PGDIR_MASK (~(PGDIR_SIZE-1))
	64
	65	#define USER_PTRS_PER_PGD (TASK_SIZE/PGDIR_SIZE)
d455a369	66	#define FIRST_USER_ADDRESS 0
1da177e4 LT	67
	68	#define USER_PGD_PTRS (PAGE_OFFSET >> PGDIR_SHIFT)
	69	#define KERNEL_PGD_PTRS (PTRS_PER_PGD-USER_PGD_PTRS)
	70
	71	#define TWOLEVEL_PGDIR_SHIFT 22
	72	#define BOOT_USER_PGD_PTRS (__PAGE_OFFSET >> TWOLEVEL_PGDIR_SHIFT)
	73	#define BOOT_KERNEL_PGD_PTRS (1024-BOOT_USER_PGD_PTRS)
	74
	75	/* Just any arbitrary offset to the start of the vmalloc VM area: the
	76	* current 8MB value just means that there will be a 8MB "hole" after the
	77	* physical memory until the kernel virtual memory starts. That means that
	78	* any out-of-bounds memory accesses will hopefully be caught.
	79	* The vmalloc() routines leaves a hole of 4kB between each vmalloced
	80	* area for the same reason. ;)
	81	*/
	82	#define VMALLOC_OFFSET (810241024)
	83	#define VMALLOC_START (((unsigned long) high_memory + vmalloc_earlyreserve + \
	84	2*VMALLOC_OFFSET-1) & ~(VMALLOC_OFFSET-1))
	85	#ifdef CONFIG_HIGHMEM
	86	# define VMALLOC_END (PKMAP_BASE-2*PAGE_SIZE)
	87	#else
	88	# define VMALLOC_END (FIXADDR_START-2*PAGE_SIZE)
	89	#endif
	90
	91	/*
9b4ee40e	92	* _PAGE_PSE set in the page directory entry just means that
1da177e4 LT	93	* the page directory entry points directly to a 4MB-aligned block of
	94	* memory.
	95	*/
	96	#define _PAGE_BIT_PRESENT 0
	97	#define _PAGE_BIT_RW 1
	98	#define _PAGE_BIT_USER 2
	99	#define _PAGE_BIT_PWT 3
	100	#define _PAGE_BIT_PCD 4
	101	#define _PAGE_BIT_ACCESSED 5
	102	#define _PAGE_BIT_DIRTY 6
	103	#define _PAGE_BIT_PSE 7 /* 4 MB (or 2MB) page, Pentium+, if present.. */
	104	#define _PAGE_BIT_GLOBAL 8 /* Global TLB entry PPro+ */
	105	#define _PAGE_BIT_UNUSED1 9 /* available for programmer */
	106	#define _PAGE_BIT_UNUSED2 10
	107	#define _PAGE_BIT_UNUSED3 11
	108	#define _PAGE_BIT_NX 63
	109
	110	#define _PAGE_PRESENT 0x001
	111	#define _PAGE_RW 0x002
	112	#define _PAGE_USER 0x004
	113	#define _PAGE_PWT 0x008
	114	#define _PAGE_PCD 0x010
	115	#define _PAGE_ACCESSED 0x020
	116	#define _PAGE_DIRTY 0x040
	117	#define _PAGE_PSE 0x080 /* 4 MB (or 2MB) page, Pentium+, if present.. */
	118	#define _PAGE_GLOBAL 0x100 /* Global TLB entry PPro+ */
	119	#define _PAGE_UNUSED1 0x200 /* available for programmer */
	120	#define _PAGE_UNUSED2 0x400
	121	#define _PAGE_UNUSED3 0x800
	122
9b4ee40e PBG	123	/* If _PAGE_PRESENT is clear, we use these: */
	124	#define _PAGE_FILE 0x040 /* nonlinear file mapping, saved PTE; unset:swap */
	125	#define _PAGE_PROTNONE 0x080 /* if the user mapped it with PROT_NONE;
	126	pte_present gives true */
1da177e4 LT	127	#ifdef CONFIG_X86_PAE
	128	#define _PAGE_NX (1ULL<<_PAGE_BIT_NX)
	129	#else
	130	#define _PAGE_NX 0
	131	#endif
	132
	133	#define _PAGE_TABLE (_PAGE_PRESENT \| _PAGE_RW \| _PAGE_USER \| _PAGE_ACCESSED \| _PAGE_DIRTY)
	134	#define _KERNPG_TABLE (_PAGE_PRESENT \| _PAGE_RW \| _PAGE_ACCESSED \| _PAGE_DIRTY)
	135	#define _PAGE_CHG_MASK (PTE_MASK \| _PAGE_ACCESSED \| _PAGE_DIRTY)
	136
	137	#define PAGE_NONE \
	138	__pgprot(_PAGE_PROTNONE \| _PAGE_ACCESSED)
	139	#define PAGE_SHARED \
	140	__pgprot(_PAGE_PRESENT \| _PAGE_RW \| _PAGE_USER \| _PAGE_ACCESSED)
	141
	142	#define PAGE_SHARED_EXEC \
	143	__pgprot(_PAGE_PRESENT \| _PAGE_RW \| _PAGE_USER \| _PAGE_ACCESSED)
	144	#define PAGE_COPY_NOEXEC \
	145	__pgprot(_PAGE_PRESENT \| _PAGE_USER \| _PAGE_ACCESSED \| _PAGE_NX)
	146	#define PAGE_COPY_EXEC \
	147	__pgprot(_PAGE_PRESENT \| _PAGE_USER \| _PAGE_ACCESSED)
	148	#define PAGE_COPY \
	149	PAGE_COPY_NOEXEC
	150	#define PAGE_READONLY \
	151	__pgprot(_PAGE_PRESENT \| _PAGE_USER \| _PAGE_ACCESSED \| _PAGE_NX)
	152	#define PAGE_READONLY_EXEC \
	153	__pgprot(_PAGE_PRESENT \| _PAGE_USER \| _PAGE_ACCESSED)
	154
	155	#define _PAGE_KERNEL \
	156	(_PAGE_PRESENT \| _PAGE_RW \| _PAGE_DIRTY \| _PAGE_ACCESSED \| _PAGE_NX)
	157	#define _PAGE_KERNEL_EXEC \
	158	(_PAGE_PRESENT \| _PAGE_RW \| _PAGE_DIRTY \| _PAGE_ACCESSED)
	159
	160	extern unsigned long long __PAGE_KERNEL, __PAGE_KERNEL_EXEC;
	161	#define __PAGE_KERNEL_RO (__PAGE_KERNEL & ~_PAGE_RW)
	162	#define __PAGE_KERNEL_NOCACHE (__PAGE_KERNEL \| _PAGE_PCD)
	163	#define __PAGE_KERNEL_LARGE (__PAGE_KERNEL \| _PAGE_PSE)
	164	#define __PAGE_KERNEL_LARGE_EXEC (__PAGE_KERNEL_EXEC \| _PAGE_PSE)
	165
	166	#define PAGE_KERNEL __pgprot(__PAGE_KERNEL)
	167	#define PAGE_KERNEL_RO __pgprot(__PAGE_KERNEL_RO)
	168	#define PAGE_KERNEL_EXEC __pgprot(__PAGE_KERNEL_EXEC)
	169	#define PAGE_KERNEL_NOCACHE __pgprot(__PAGE_KERNEL_NOCACHE)
	170	#define PAGE_KERNEL_LARGE __pgprot(__PAGE_KERNEL_LARGE)
	171	#define PAGE_KERNEL_LARGE_EXEC __pgprot(__PAGE_KERNEL_LARGE_EXEC)
	172
	173	/*
	174	* The i386 can't do page protection for execute, and considers that
	175	* the same are read. Also, write permissions imply read permissions.
	176	* This is the closest we can get..
	177	*/
	178	#define __P000 PAGE_NONE
	179	#define __P001 PAGE_READONLY
	180	#define __P010 PAGE_COPY
	181	#define __P011 PAGE_COPY
	182	#define __P100 PAGE_READONLY_EXEC
	183	#define __P101 PAGE_READONLY_EXEC
	184	#define __P110 PAGE_COPY_EXEC
	185	#define __P111 PAGE_COPY_EXEC
	186
	187	#define __S000 PAGE_NONE
	188	#define __S001 PAGE_READONLY
	189	#define __S010 PAGE_SHARED
	190	#define __S011 PAGE_SHARED
191	#define __S100 PAGE_READONLY_EXEC
192	#define __S101 PAGE_READONLY_EXEC
193	#define __S110 PAGE_SHARED_EXEC
194	#define __S111 PAGE_SHARED_EXEC
195
196	/*
197	* Define this if things work differently on an i386 and an i486:
198	* it will (on an i486) warn about kernel memory accesses that are
e49332bd	199	* done without a 'access_ok(VERIFY_WRITE,..)'
1da177e4	200	*/
e49332bd	201	#undef TEST_ACCESS_OK
1da177e4 LT	202
	203	/* The boot page tables (all created as a single array) */
	204	extern unsigned long pg0[];
	205
	206	#define pte_present(x) ((x).pte_low & (_PAGE_PRESENT \| _PAGE_PROTNONE))
1da177e4	207
705e87c0 HD	208	/* To avoid harmful races, pmd_none(x) should check only the lower when PAE */
705e87c0 HD	209	#define pmd_none(x) (!(unsigned long)pmd_val(x))
1da177e4	210	#define pmd_present(x) (pmd_val(x) & _PAGE_PRESENT)
1da177e4 LT	211	#define pmd_bad(x) ((pmd_val(x) & (~PAGE_MASK & ~_PAGE_USER)) != _KERNPG_TABLE)
	212
	213
	214	#define pages_to_mb(x) ((x) >> (20-PAGE_SHIFT))
	215
	216	/*
	217	* The following only work if pte_present() is true.
	218	* Undefined behaviour if not..
	219	*/
	220	static inline int pte_user(pte_t pte) { return (pte).pte_low & _PAGE_USER; }
	221	static inline int pte_read(pte_t pte) { return (pte).pte_low & _PAGE_USER; }
	222	static inline int pte_dirty(pte_t pte) { return (pte).pte_low & _PAGE_DIRTY; }
	223	static inline int pte_young(pte_t pte) { return (pte).pte_low & _PAGE_ACCESSED; }
	224	static inline int pte_write(pte_t pte) { return (pte).pte_low & _PAGE_RW; }
8f860591	225	static inline int pte_huge(pte_t pte) { return (pte).pte_low & _PAGE_PSE; }
1da177e4 LT	226
	227	/*
	228	* The following only works if pte_present() is not true.
	229	*/
	230	static inline int pte_file(pte_t pte) { return (pte).pte_low & _PAGE_FILE; }
	231
	232	static inline pte_t pte_rdprotect(pte_t pte) { (pte).pte_low &= ~_PAGE_USER; return pte; }
	233	static inline pte_t pte_exprotect(pte_t pte) { (pte).pte_low &= ~_PAGE_USER; return pte; }
	234	static inline pte_t pte_mkclean(pte_t pte) { (pte).pte_low &= ~_PAGE_DIRTY; return pte; }
	235	static inline pte_t pte_mkold(pte_t pte) { (pte).pte_low &= ~_PAGE_ACCESSED; return pte; }
	236	static inline pte_t pte_wrprotect(pte_t pte) { (pte).pte_low &= ~_PAGE_RW; return pte; }
	237	static inline pte_t pte_mkread(pte_t pte) { (pte).pte_low \|= _PAGE_USER; return pte; }
	238	static inline pte_t pte_mkexec(pte_t pte) { (pte).pte_low \|= _PAGE_USER; return pte; }
	239	static inline pte_t pte_mkdirty(pte_t pte) { (pte).pte_low \|= _PAGE_DIRTY; return pte; }
	240	static inline pte_t pte_mkyoung(pte_t pte) { (pte).pte_low \|= _PAGE_ACCESSED; return pte; }
	241	static inline pte_t pte_mkwrite(pte_t pte) { (pte).pte_low \|= _PAGE_RW; return pte; }
8f860591	242	static inline pte_t pte_mkhuge(pte_t pte) { (pte).pte_low \|= _PAGE_PSE; return pte; }
1da177e4 LT	243
	244	#ifdef CONFIG_X86_PAE
	245	# include <asm/pgtable-3level.h>
	246	#else
	247	# include <asm/pgtable-2level.h>
	248	#endif
	249
da181a8b	250	#ifndef CONFIG_PARAVIRT
789e6ac0 ZA	251	/*
	252	* Rules for using pte_update - it must be called after any PTE update which
	253	* has not been done using the set_pte / clear_pte interfaces. It is used by
	254	* shadow mode hypervisors to resynchronize the shadow page tables. Kernel PTE
	255	* updates should either be sets, clears, or set_pte_atomic for P->P
	256	* transitions, which means this hook should only be called for user PTEs.
	257	* This hook implies a P->P protection or access change has taken place, which
	258	* requires a subsequent TLB flush. The notification can optionally be delayed
	259	* until the TLB flush event by using the pte_update_defer form of the
	260	* interface, but care must be taken to assure that the flush happens while
	261	* still holding the same page table lock so that the shadow and primary pages
	262	* do not become out of sync on SMP.
	263	*/
	264	#define pte_update(mm, addr, ptep) do { } while (0)
	265	#define pte_update_defer(mm, addr, ptep) do { } while (0)
da181a8b	266	#endif
789e6ac0	267
2965a0e6 RR	268	/*
	269	* We only update the dirty/accessed state if we set
	270	* the dirty bit by hand in the kernel, since the hardware
	271	* will do the accessed bit for us, and we don't want to
	272	* race with other CPU's that might be updating the dirty
	273	* bit at the same time.
	274	*/
	275	#define __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS
	276	#define ptep_set_access_flags(vma, address, ptep, entry, dirty) \
	277	do { \
	278	if (dirty) { \
	279	(ptep)->pte_low = (entry).pte_low; \
789e6ac0	280	pte_update_defer((vma)->vm_mm, (addr), (ptep)); \
2965a0e6 RR	281	flush_tlb_page(vma, address); \
	282	} \
	283	} while (0)
	284
25e4df5b ZA	285	/*
	286	* We don't actually have these, but we want to advertise them so that
	287	* we can encompass the flush here.
	288	*/
6049742d	289	#define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_DIRTY
6049742d	290	#define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
25e4df5b	291
d6d861e3 ZA	292	/*
	293	* Rules for using ptep_establish: the pte MUST be a user pte, and
	294	* must be a present->present transition.
	295	*/
	296	#define __HAVE_ARCH_PTEP_ESTABLISH
	297	#define ptep_establish(vma, address, ptep, pteval) \
	298	do { \
	299	set_pte_present((vma)->vm_mm, address, ptep, pteval); \
	300	flush_tlb_page(vma, address); \
	301	} while (0)
	302
25e4df5b ZA	303	#define __HAVE_ARCH_PTEP_CLEAR_DIRTY_FLUSH
	304	#define ptep_clear_flush_dirty(vma, address, ptep) \
	305	({ \
	306	int __dirty; \
	307	__dirty = pte_dirty(*(ptep)); \
	308	if (__dirty) { \
	309	clear_bit(_PAGE_BIT_DIRTY, &(ptep)->pte_low); \
789e6ac0	310	pte_update_defer((vma)->vm_mm, (addr), (ptep)); \
25e4df5b ZA	311	flush_tlb_page(vma, address); \
	312	} \
	313	__dirty; \
	314	})
	315
	316	#define __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH
	317	#define ptep_clear_flush_young(vma, address, ptep) \
	318	({ \
	319	int __young; \
	320	__young = pte_young(*(ptep)); \
	321	if (__young) { \
	322	clear_bit(_PAGE_BIT_ACCESSED, &(ptep)->pte_low); \
789e6ac0	323	pte_update_defer((vma)->vm_mm, (addr), (ptep)); \
25e4df5b ZA	324	flush_tlb_page(vma, address); \
	325	} \
	326	__young; \
	327	})
1da177e4	328
6049742d	329	#define __HAVE_ARCH_PTEP_GET_AND_CLEAR_FULL
a600388d ZA	330	static inline pte_t ptep_get_and_clear_full(struct mm_struct mm, unsigned long addr, pte_t ptep, int full)
	331	{
	332	pte_t pte;
	333	if (full) {
	334	pte = *ptep;
6e5882cf	335	pte_clear(mm, addr, ptep);
a600388d ZA	336	} else {
	337	pte = ptep_get_and_clear(mm, addr, ptep);
	338	}
	339	return pte;
	340	}
	341
6049742d	342	#define __HAVE_ARCH_PTEP_SET_WRPROTECT
1da177e4 LT	343	static inline void ptep_set_wrprotect(struct mm_struct mm, unsigned long addr, pte_t ptep)
	344	{
	345	clear_bit(_PAGE_BIT_RW, &ptep->pte_low);
789e6ac0	346	pte_update(mm, addr, ptep);
1da177e4 LT	347	}
1da177e4 LT	348
d7271b14 ZA	349	/*
	350	* clone_pgd_range(pgd_t dst, pgd_t src, int count);
	351	*
	352	* dst - pointer to pgd range anwhere on a pgd page
	353	* src - ""
	354	* count - the number of pgds to copy.
	355	*
	356	* dst and src can be on the same page, but the range must not overlap,
	357	* and must not cross a page boundary.
	358	*/
	359	static inline void clone_pgd_range(pgd_t dst, pgd_t src, int count)
	360	{
	361	memcpy(dst, src, count * sizeof(pgd_t));
	362	}
	363
1da177e4 LT	364	/*
	365	* Macro to mark a page protection value as "uncacheable". On processors which do not support
	366	* it, this is a no-op.
	367	*/
	368	#define pgprot_noncached(prot) ((boot_cpu_data.x86 > 3) \
	369	? (__pgprot(pgprot_val(prot) \| _PAGE_PCD \| _PAGE_PWT)) : (prot))
	370
	371	/*
	372	* Conversion functions: convert a page and protection to a page entry,
	373	* and a page entry and page directory to the page they refer to.
	374	*/
	375
	376	#define mk_pte(page, pgprot) pfn_pte(page_to_pfn(page), (pgprot))
1da177e4 LT	377
	378	static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
	379	{
	380	pte.pte_low &= _PAGE_CHG_MASK;
	381	pte.pte_low \|= pgprot_val(newprot);
	382	#ifdef CONFIG_X86_PAE
	383	/*
	384	* Chop off the NX bit (if present), and add the NX portion of
	385	* the newprot (if present):
	386	*/
	387	pte.pte_high &= ~(1 << (_PAGE_BIT_NX - 32));
	388	pte.pte_high \|= (pgprot_val(newprot) >> 32) & \
	389	(__supported_pte_mask >> 32);
	390	#endif
	391	return pte;
	392	}
	393
1da177e4 LT	394	#define pmd_large(pmd) \
	395	((pmd_val(pmd) & (_PAGE_PSE\|_PAGE_PRESENT)) == (_PAGE_PSE\|_PAGE_PRESENT))
	396
	397	/*
	398	* the pgd page can be thought of an array like this: pgd_t[PTRS_PER_PGD]
	399	*
	400	* this macro returns the index of the entry in the pgd page which would
	401	* control the given virtual address
	402	*/
	403	#define pgd_index(address) (((address) >> PGDIR_SHIFT) & (PTRS_PER_PGD-1))
	404	#define pgd_index_k(addr) pgd_index(addr)
	405
	406	/*
	407	* pgd_offset() returns a (pgd_t *)
	408	* pgd_index() is used get the offset into the pgd page's array of pgd_t's;
	409	*/
	410	#define pgd_offset(mm, address) ((mm)->pgd+pgd_index(address))
	411
	412	/*
	413	* a shortcut which implies the use of the kernel's pgd, instead
	414	* of a process's
	415	*/
	416	#define pgd_offset_k(address) pgd_offset(&init_mm, address)
	417
	418	/*
	419	* the pmd page can be thought of an array like this: pmd_t[PTRS_PER_PMD]
	420	*
	421	* this macro returns the index of the entry in the pmd page which would
	422	* control the given virtual address
	423	*/
	424	#define pmd_index(address) \
	425	(((address) >> PMD_SHIFT) & (PTRS_PER_PMD-1))
	426
	427	/*
	428	* the pte page can be thought of an array like this: pte_t[PTRS_PER_PTE]
	429	*
	430	* this macro returns the index of the entry in the pte page which would
	431	* control the given virtual address
	432	*/
	433	#define pte_index(address) \
	434	(((address) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
	435	#define pte_offset_kernel(dir, address) \
46a82b2d	436	((pte_t ) pmd_page_vaddr((dir)) + pte_index(address))
1da177e4	437
ca140fda PBG	438	#define pmd_page(pmd) (pfn_to_page(pmd_val(pmd) >> PAGE_SHIFT))
ca140fda PBG	439
46a82b2d	440	#define pmd_page_vaddr(pmd) \
ca140fda PBG	441	((unsigned long) __va(pmd_val(pmd) & PAGE_MASK))
ca140fda PBG	442
1da177e4 LT	443	/*
	444	* Helper function that returns the kernel pagetable entry controlling
	445	* the virtual address 'address'. NULL means no pagetable entry present.
	446	* NOTE: the return type is pte_t but if the pmd is PSE then we return it
	447	* as a pte too.
	448	*/
	449	extern pte_t *lookup_address(unsigned long address);
	450
	451	/*
	452	* Make a given kernel text page executable/non-executable.
	453	* Returns the previous executability setting of that page (which
	454	* is used to restore the previous state). Used by the SMP bootup code.
	455	* NOTE: this is an __init function for security reasons.
	456	*/
	457	#ifdef CONFIG_X86_PAE
	458	extern int set_kernel_exec(unsigned long vaddr, int enable);
	459	#else
	460	static inline int set_kernel_exec(unsigned long vaddr, int enable) { return 0;}
	461	#endif
	462
1da177e4 LT	463	#if defined(CONFIG_HIGHPTE)
	464	#define pte_offset_map(dir, address) \
	465	((pte_t )kmap_atomic(pmd_page((dir)),KM_PTE0) + pte_index(address))
	466	#define pte_offset_map_nested(dir, address) \
	467	((pte_t )kmap_atomic(pmd_page((dir)),KM_PTE1) + pte_index(address))
	468	#define pte_unmap(pte) kunmap_atomic(pte, KM_PTE0)
	469	#define pte_unmap_nested(pte) kunmap_atomic(pte, KM_PTE1)
	470	#else
	471	#define pte_offset_map(dir, address) \
	472	((pte_t )page_address(pmd_page((dir))) + pte_index(address))
	473	#define pte_offset_map_nested(dir, address) pte_offset_map(dir, address)
	474	#define pte_unmap(pte) do { } while (0)
	475	#define pte_unmap_nested(pte) do { } while (0)
	476	#endif
	477
23002d88 ZA	478	/* Clear a kernel PTE and flush it from the TLB */
	479	#define kpte_clear_flush(ptep, vaddr) \
	480	do { \
	481	pte_clear(&init_mm, vaddr, ptep); \
	482	__flush_tlb_one(vaddr); \
	483	} while (0)
	484
1da177e4 LT	485	/*
	486	* The i386 doesn't have any external MMU info: the kernel page
	487	* tables contain all the necessary information.
1da177e4 LT	488	*/
1da177e4 LT	489	#define update_mmu_cache(vma,address,pte) do { } while (0)
1da177e4 LT	490	#endif /* !__ASSEMBLY__ */
1da177e4 LT	491
05b79bdc	492	#ifdef CONFIG_FLATMEM
1da177e4	493	#define kern_addr_valid(addr) (1)
05b79bdc	494	#endif /* CONFIG_FLATMEM */
1da177e4	495
1da177e4 LT	496	#define io_remap_pfn_range(vma, vaddr, pfn, size, prot) \
	497	remap_pfn_range(vma, vaddr, pfn, size, prot)
	498
	499	#define MK_IOSPACE_PFN(space, pfn) (pfn)
	500	#define GET_IOSPACE(pfn) 0
	501	#define GET_PFN(pfn) (pfn)
	502
1da177e4 LT	503	#include <asm-generic/pgtable.h>
	504
	505	#endif /* _I386_PGTABLE_H */