arch/x86/include/asm/pgtable_32.h

   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
  25 struct mm_struct;
  26 struct vm_area_struct;
  27
  28 extern pgd_t swapper_pg_dir[1024];
  29 extern pgd_t initial_page_table[1024];
  30 extern pmd_t initial_pg_pmd[];
  31
  32 void paging_init(void);
  33 void 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)           \
  43 do {                                            \
  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 */