linux/arch/x86/include/asm/pgtable_32.h
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   1#ifndef _ASM_X86_PGTABLE_32_H
   2#define _ASM_X86_PGTABLE_32_H
   3
   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>
  18#include <asm/paravirt.h>
  19
  20#include <linux/bitops.h>
  21#include <linux/slab.h>
  22#include <linux/list.h>
  23#include <linux/spinlock.h>
  24
  25struct mm_struct;
  26struct vm_area_struct;
  27
  28extern pgd_t swapper_pg_dir[1024];
  29
  30static inline void pgtable_cache_init(void) { }
  31static inline void check_pgt_cache(void) { }
  32void paging_init(void);
  33
  34extern void set_pmd_pfn(unsigned long, unsigned long, pgprot_t);
  35
  36/*
  37 * The Linux x86 paging architecture is 'compile-time dual-mode', it
  38 * implements both the traditional 2-level x86 page tables and the
  39 * newer 3-level PAE-mode page tables.
  40 */
  41#ifdef CONFIG_X86_PAE
  42# include <asm/pgtable-3level-defs.h>
  43# define PMD_SIZE       (1UL << PMD_SHIFT)
  44# define PMD_MASK       (~(PMD_SIZE - 1))
  45#else
  46# include <asm/pgtable-2level-defs.h>
  47#endif
  48
  49#define PGDIR_SIZE      (1UL << PGDIR_SHIFT)
  50#define PGDIR_MASK      (~(PGDIR_SIZE - 1))
  51
  52/* Just any arbitrary offset to the start of the vmalloc VM area: the
  53 * current 8MB value just means that there will be a 8MB "hole" after the
  54 * physical memory until the kernel virtual memory starts.  That means that
  55 * any out-of-bounds memory accesses will hopefully be caught.
  56 * The vmalloc() routines leaves a hole of 4kB between each vmalloced
  57 * area for the same reason. ;)
  58 */
  59#define VMALLOC_OFFSET  (8 * 1024 * 1024)
  60#define VMALLOC_START   ((unsigned long)high_memory + VMALLOC_OFFSET)
  61#ifdef CONFIG_X86_PAE
  62#define LAST_PKMAP 512
  63#else
  64#define LAST_PKMAP 1024
  65#endif
  66
  67#define PKMAP_BASE ((FIXADDR_BOOT_START - PAGE_SIZE * (LAST_PKMAP + 1)) \
  68                    & PMD_MASK)
  69
  70#ifdef CONFIG_HIGHMEM
  71# define VMALLOC_END    (PKMAP_BASE - 2 * PAGE_SIZE)
  72#else
  73# define VMALLOC_END    (FIXADDR_START - 2 * PAGE_SIZE)
  74#endif
  75
  76#define MAXMEM  (VMALLOC_END - PAGE_OFFSET - __VMALLOC_RESERVE)
  77
  78/*
  79 * Define this if things work differently on an i386 and an i486:
  80 * it will (on an i486) warn about kernel memory accesses that are
  81 * done without a 'access_ok(VERIFY_WRITE,..)'
  82 */
  83#undef TEST_ACCESS_OK
  84
  85/* The boot page tables (all created as a single array) */
  86extern unsigned long pg0[];
  87
  88#define pte_present(x)  ((x).pte_low & (_PAGE_PRESENT | _PAGE_PROTNONE))
  89
  90/* To avoid harmful races, pmd_none(x) should check only the lower when PAE */
  91#define pmd_none(x)     (!(unsigned long)pmd_val((x)))
  92#define pmd_present(x)  (pmd_val((x)) & _PAGE_PRESENT)
  93#define pmd_bad(x) ((pmd_val(x) & (PTE_FLAGS_MASK & ~_PAGE_USER)) != _KERNPG_TABLE)
  94
  95#define pages_to_mb(x) ((x) >> (20-PAGE_SHIFT))
  96
  97#ifdef CONFIG_X86_PAE
  98# include <asm/pgtable-3level.h>
  99#else
 100# include <asm/pgtable-2level.h>
 101#endif
 102
 103/*
 104 * Macro to mark a page protection value as "uncacheable".
 105 * On processors which do not support it, this is a no-op.
 106 */
 107#define pgprot_noncached(prot)                                  \
 108        ((boot_cpu_data.x86 > 3)                                \
 109         ? (__pgprot(pgprot_val(prot) | _PAGE_PCD | _PAGE_PWT)) \
 110         : (prot))
 111
 112/*
 113 * Conversion functions: convert a page and protection to a page entry,
 114 * and a page entry and page directory to the page they refer to.
 115 */
 116#define mk_pte(page, pgprot)    pfn_pte(page_to_pfn(page), (pgprot))
 117
 118
 119static inline int pud_large(pud_t pud) { return 0; }
 120
 121/*
 122 * the pmd page can be thought of an array like this: pmd_t[PTRS_PER_PMD]
 123 *
 124 * this macro returns the index of the entry in the pmd page which would
 125 * control the given virtual address
 126 */
 127#define pmd_index(address)                              \
 128        (((address) >> PMD_SHIFT) & (PTRS_PER_PMD - 1))
 129
 130/*
 131 * the pte page can be thought of an array like this: pte_t[PTRS_PER_PTE]
 132 *
 133 * this macro returns the index of the entry in the pte page which would
 134 * control the given virtual address
 135 */
 136#define pte_index(address)                                      \
 137        (((address) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
 138#define pte_offset_kernel(dir, address)                         \
 139        ((pte_t *)pmd_page_vaddr(*(dir)) +  pte_index((address)))
 140
 141#define pmd_page(pmd) (pfn_to_page(pmd_val((pmd)) >> PAGE_SHIFT))
 142
 143#define pmd_page_vaddr(pmd)                                     \
 144        ((unsigned long)__va(pmd_val((pmd)) & PTE_PFN_MASK))
 145
 146#if defined(CONFIG_HIGHPTE)
 147#define pte_offset_map(dir, address)                                    \
 148        ((pte_t *)kmap_atomic_pte(pmd_page(*(dir)), KM_PTE0) +          \
 149         pte_index((address)))
 150#define pte_offset_map_nested(dir, address)                             \
 151        ((pte_t *)kmap_atomic_pte(pmd_page(*(dir)), KM_PTE1) +          \
 152         pte_index((address)))
 153#define pte_unmap(pte) kunmap_atomic((pte), KM_PTE0)
 154#define pte_unmap_nested(pte) kunmap_atomic((pte), KM_PTE1)
 155#else
 156#define pte_offset_map(dir, address)                                    \
 157        ((pte_t *)page_address(pmd_page(*(dir))) + pte_index((address)))
 158#define pte_offset_map_nested(dir, address) pte_offset_map((dir), (address))
 159#define pte_unmap(pte) do { } while (0)
 160#define pte_unmap_nested(pte) do { } while (0)
 161#endif
 162
 163/* Clear a kernel PTE and flush it from the TLB */
 164#define kpte_clear_flush(ptep, vaddr)           \
 165do {                                            \
 166        pte_clear(&init_mm, (vaddr), (ptep));   \
 167        __flush_tlb_one((vaddr));               \
 168} while (0)
 169
 170/*
 171 * The i386 doesn't have any external MMU info: the kernel page
 172 * tables contain all the necessary information.
 173 */
 174#define update_mmu_cache(vma, address, pte) do { } while (0)
 175
 176#endif /* !__ASSEMBLY__ */
 177
 178/*
 179 * kern_addr_valid() is (1) for FLATMEM and (0) for
 180 * SPARSEMEM and DISCONTIGMEM
 181 */
 182#ifdef CONFIG_FLATMEM
 183#define kern_addr_valid(addr)   (1)
 184#else
 185#define kern_addr_valid(kaddr)  (0)
 186#endif
 187
 188#define io_remap_pfn_range(vma, vaddr, pfn, size, prot) \
 189        remap_pfn_range(vma, vaddr, pfn, size, prot)
 190
 191#endif /* _ASM_X86_PGTABLE_32_H */
 192
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