LXR linux/arch/x86/include/asm/pgtable

   1/* SPDX-License-Identifier: GPL-2.0 */
   2#ifndef _ASM_X86_PGTABLE_32_H
   3#define _ASM_X86_PGTABLE_32_H
   4
   5#include <asm/pgtable_32_types.h>
   6
   7/*
   8 * The Linux memory management assumes a three-level page table setup. On
   9 * the i386, we use that, but "fold" the mid level into the top-level page
  10 * table, so that we physically have the same two-level page table as the
  11 * i386 mmu expects.
  12 *
  13 * This file contains the functions and defines necessary to modify and use
  14 * the i386 page table tree.
  15 */
  16#ifndef __ASSEMBLY__
  17#include <asm/processor.h>
  18#include <linux/threads.h>
  19#include <asm/paravirt.h>
  20
  21#include <linux/bitops.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];
  29extern pgd_t initial_page_table[1024];
  30extern pmd_t initial_pg_pmd[];
  31
  32void paging_init(void);
  33void sync_initial_page_table(void);
  34
  35#ifdef CONFIG_X86_PAE
  36# include <asm/pgtable-3level.h>
  37#else
  38# include <asm/pgtable-2level.h>
  39#endif
  40
  41/* Clear a kernel PTE and flush it from the TLB */
  42#define kpte_clear_flush(ptep, vaddr)           \
  43do {                                            \
  44        pte_clear(&init_mm, (vaddr), (ptep));   \
  45        flush_tlb_one_kernel((vaddr));          \
  46} while (0)
  47
  48#endif /* !__ASSEMBLY__ */
  49
  50/*
  51 * kern_addr_valid() is (1) for FLATMEM and (0) for SPARSEMEM
  52 */
  53#ifdef CONFIG_FLATMEM
  54#define kern_addr_valid(addr)   (1)
  55#else
  56#define kern_addr_valid(kaddr)  (0)
  57#endif
  58
  59/*
  60 * This is used to calculate the .brk reservation for initial pagetables.
  61 * Enough space is reserved to allocate pagetables sufficient to cover all
  62 * of LOWMEM_PAGES, which is an upper bound on the size of the direct map of
  63 * lowmem.
  64 *
  65 * With PAE paging (PTRS_PER_PMD > 1), we allocate PTRS_PER_PGD == 4 pages for
  66 * the PMD's in addition to the pages required for the last level pagetables.
  67 */
  68#if PTRS_PER_PMD > 1
  69#define PAGE_TABLE_SIZE(pages) (((pages) / PTRS_PER_PMD) + PTRS_PER_PGD)
  70#else
  71#define PAGE_TABLE_SIZE(pages) ((pages) / PTRS_PER_PGD)
  72#endif
  73
  74/*
  75 * Number of possible pages in the lowmem region.
  76 *
  77 * We shift 2 by 31 instead of 1 by 32 to the left in order to avoid a
  78 * gas warning about overflowing shift count when gas has been compiled
  79 * with only a host target support using a 32-bit type for internal
  80 * representation.
  81 */
  82#define LOWMEM_PAGES ((((_ULL(2)<<31) - __PAGE_OFFSET) >> PAGE_SHIFT))
  83
  84#endif /* _ASM_X86_PGTABLE_32_H */
  85