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 * This is used to calculate the .brk reservation for initial pagetables. 52 * Enough space is reserved to allocate pagetables sufficient to cover all 53 * of LOWMEM_PAGES, which is an upper bound on the size of the direct map of 54 * lowmem. 55 * 56 * With PAE paging (PTRS_PER_PMD > 1), we allocate PTRS_PER_PGD == 4 pages for 57 * the PMD's in addition to the pages required for the last level pagetables. 58 */ 59 #if PTRS_PER_PMD > 1 60 #define PAGE_TABLE_SIZE(pages) (((pages) / PTRS_PER_PMD) + PTRS_PER_PGD) 61 #else 62 #define PAGE_TABLE_SIZE(pages) ((pages) / PTRS_PER_PGD) 63 #endif 64 65 /* 66 * Number of possible pages in the lowmem region. 67 * 68 * We shift 2 by 31 instead of 1 by 32 to the left in order to avoid a 69 * gas warning about overflowing shift count when gas has been compiled 70 * with only a host target support using a 32-bit type for internal 71 * representation. 72 */ 73 #define LOWMEM_PAGES ((((_ULL(2)<<31) - __PAGE_OFFSET) >> PAGE_SHIFT)) 74 75 #endif /* _ASM_X86_PGTABLE_32_H */ 76