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 /* 36 * Define this if things work differently on an i386 and an i486: 37 * it will (on an i486) warn about kernel memory accesses that are 38 * done without a 'access_ok( ..)' 39 */ 40 #undef TEST_ACCESS_OK 41 42 #ifdef CONFIG_X86_PAE 43 # include <asm/pgtable-3level.h> 44 #else 45 # include <asm/pgtable-2level.h> 46 #endif 47 48 #if defined(CONFIG_HIGHPTE) 49 #define pte_offset_map(dir, address) \ 50 ((pte_t *)kmap_atomic(pmd_page(*(dir))) + \ 51 pte_index((address))) 52 #define pte_unmap(pte) kunmap_atomic((pte)) 53 #else 54 #define pte_offset_map(dir, address) \ 55 ((pte_t *)page_address(pmd_page(*(dir))) + pte_index((address))) 56 #define pte_unmap(pte) do { } while (0) 57 #endif 58 59 /* Clear a kernel PTE and flush it from the TLB */ 60 #define kpte_clear_flush(ptep, vaddr) \ 61 do { \ 62 pte_clear(&init_mm, (vaddr), (ptep)); \ 63 __flush_tlb_one_kernel((vaddr)); \ 64 } while (0) 65 66 #endif /* !__ASSEMBLY__ */ 67 68 /* 69 * kern_addr_valid() is (1) for FLATMEM and (0) for 70 * SPARSEMEM and DISCONTIGMEM 71 */ 72 #ifdef CONFIG_FLATMEM 73 #define kern_addr_valid(addr) (1) 74 #else 75 #define kern_addr_valid(kaddr) (0) 76 #endif 77 78 /* 79 * This is how much memory in addition to the memory covered up to 80 * and including _end we need mapped initially. 81 * We need: 82 * (KERNEL_IMAGE_SIZE/4096) / 1024 pages (worst case, non PAE) 83 * (KERNEL_IMAGE_SIZE/4096) / 512 + 4 pages (worst case for PAE) 84 * 85 * Modulo rounding, each megabyte assigned here requires a kilobyte of 86 * memory, which is currently unreclaimed. 87 * 88 * This should be a multiple of a page. 89 * 90 * KERNEL_IMAGE_SIZE should be greater than pa(_end) 91 * and small than max_low_pfn, otherwise will waste some page table entries 92 */ 93 #if PTRS_PER_PMD > 1 94 #define PAGE_TABLE_SIZE(pages) (((pages) / PTRS_PER_PMD) + PTRS_PER_PGD) 95 #else 96 #define PAGE_TABLE_SIZE(pages) ((pages) / PTRS_PER_PGD) 97 #endif 98 99 /* 100 * Number of possible pages in the lowmem region. 101 * 102 * We shift 2 by 31 instead of 1 by 32 to the left in order to avoid a 103 * gas warning about overflowing shift count when gas has been compiled 104 * with only a host target support using a 32-bit type for internal 105 * representation. 106 */ 107 #define LOWMEM_PAGES ((((_ULL(2)<<31) - __PAGE_OFFSET) >> PAGE_SHIFT)) 108 109 #endif /* _ASM_X86_PGTABLE_32_H */ 110