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#ifndef _I386_PGTABLE_H
#define _I386_PGTABLE_H

#include <linux/config.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>

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

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

/*
 * 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 list_head 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);

#endif /* !__ASSEMBLY__ */

/*
 * 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.
 */

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

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

#define USER_PTRS_PER_PGD       (TASK_SIZE/PGDIR_SIZE)
#define FIRST_USER_PGD_NR       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)


#ifndef __ASSEMBLY__
/* 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 + 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

/*
 * The 4MB page is guessing..  Detailed in the infamous "Chapter H"
 * of the Pentium details, but assuming intel did the straightforward
 * thing, this bit 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_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_FILE      0x040   /* set:pagecache unset:swap */
#define _PAGE_PROTNONE  0x080   /* If not present */

#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_COPY       __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_ACCESSED)
#define PAGE_READONLY   __pgprot(_PAGE_PRESENT | _PAGE_USER | _PAGE_ACCESSED)

#define _PAGE_KERNEL \
        (_PAGE_PRESENT | _PAGE_RW | _PAGE_DIRTY | _PAGE_ACCESSED)


extern unsigned long __PAGE_KERNEL;
#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             __pgprot(__PAGE_KERNEL)
#define PAGE_KERNEL_RO          __pgprot(__PAGE_KERNEL_RO)
#define PAGE_KERNEL_NOCACHE     __pgprot(__PAGE_KERNEL_NOCACHE)
#define PAGE_KERNEL_LARGE       __pgprot(__PAGE_KERNEL_LARGE)

/*
 * 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
#define __P101  PAGE_READONLY
#define __P110  PAGE_COPY
#define __P111  PAGE_COPY

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

/*
 * 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 'verify_area(VERIFY_WRITE,..)'
 */

#undef TEST_VERIFY_AREA

/* page table for 0-4MB for everybody */
extern unsigned long pg0[1024];

#define pte_present(x)  ((x).pte_low & (_PAGE_PRESENT | _PAGE_PROTNONE))
#define pte_clear(xp)   do { set_pte(xp, __pte(0)); } while (0)

#define pmd_none(x)     (!pmd_val(x))
#define pmd_present(x)  (pmd_val(x) & _PAGE_PRESENT)
#define pmd_clear(xp)   do { set_pmd(xp, __pmd(0)); } while (0)
#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_exec(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; }

/*
 * 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  int ptep_test_and_clear_dirty(pte_t *ptep)       { return test_and_clear_bit(_PAGE_BIT_DIRTY, &ptep->pte_low); }
static inline  int ptep_test_and_clear_young(pte_t *ptep)       { return test_and_clear_bit(_PAGE_BIT_ACCESSED, &ptep->pte_low); }
static inline void ptep_set_wrprotect(pte_t *ptep)              { clear_bit(_PAGE_BIT_RW, &ptep->pte_low); }
static inline void ptep_mkdirty(pte_t *ptep)                    { set_bit(_PAGE_BIT_DIRTY, &ptep->pte_low); }

/*
 * 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))
#define mk_pte_huge(entry) ((entry).pte_low |= _PAGE_PRESENT | _PAGE_PSE)

static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
{
        pte.pte_low &= _PAGE_CHG_MASK;
        pte.pte_low |= pgprot_val(newprot);
        return pte;
}

#define page_pte(page) page_pte_prot(page, __pgprot(0))

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


#ifndef CONFIG_DISCONTIGMEM
#define pmd_page(pmd) (pfn_to_page(pmd_val(pmd) >> PAGE_SHIFT))
#endif /* !CONFIG_DISCONTIGMEM */

#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))

/*
 * 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_kernel(*(dir)) +  pte_index(address))


#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

#if defined(CONFIG_HIGHPTE) && defined(CONFIG_HIGHMEM4G)
typedef u32 pte_addr_t;
#endif

#if defined(CONFIG_HIGHPTE) && defined(CONFIG_HIGHMEM64G)
typedef u64 pte_addr_t;
#endif

#if !defined(CONFIG_HIGHPTE)
typedef pte_t *pte_addr_t;
#endif

/*
 * 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)

/* Encode and de-code a swap entry */
#define __swp_type(x)                   (((x).val >> 1) & 0x1f)
#define __swp_offset(x)                 ((x).val >> 8)
#define __swp_entry(type, offset)       ((swp_entry_t) { ((type) << 1) | ((offset) << 8) })
#define __pte_to_swp_entry(pte)         ((swp_entry_t) { (pte).pte_low })
#define __swp_entry_to_pte(x)           ((pte_t) { (x).val })

#endif /* !__ASSEMBLY__ */

#ifndef CONFIG_DISCONTIGMEM
#define kern_addr_valid(addr)   (1)
#endif /* !CONFIG_DISCONTIGMEM */

#define io_remap_page_range remap_page_range

#endif /* _I386_PGTABLE_H */