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 static inline void pgtable_cache_init(void) { } 33 static inline void check_pgt_cache(void) { } 34 void paging_init(void); 35 void sync_initial_page_table(void); 36 37 /* 38 * Define this if things work differently on an i386 and an i486: 39 * it will (on an i486) warn about kernel memory accesses that are 40 * done without a 'access_ok(VERIFY_WRITE,..)' 41 */ 42 #undef TEST_ACCESS_OK 43 44 #ifdef CONFIG_X86_PAE 45 # include <asm/pgtable-3level.h> 46 #else 47 # include <asm/pgtable-2level.h> 48 #endif 49 50 #if defined(CONFIG_HIGHPTE) 51 #define pte_offset_map(dir, address) \ 52 ((pte_t *)kmap_atomic(pmd_page(*(dir))) + \ 53 pte_index((address))) 54 #define pte_unmap(pte) kunmap_atomic((pte)) 55 #else 56 #define pte_offset_map(dir, address) \ 57 ((pte_t *)page_address(pmd_page(*(dir))) + pte_index((address))) 58 #define pte_unmap(pte) do { } while (0) 59 #endif 60 61 /* Clear a kernel PTE and flush it from the TLB */ 62 #define kpte_clear_flush(ptep, vaddr) \ 63 do { \ 64 pte_clear(&init_mm, (vaddr), (ptep)); \ 65 __flush_tlb_one_kernel((vaddr)); \ 66 } while (0) 67 68 #endif /* !__ASSEMBLY__ */ 69 70 /* 71 * kern_addr_valid() is (1) for FLATMEM and (0) for 72 * SPARSEMEM and DISCONTIGMEM 73 */ 74 #ifdef CONFIG_FLATMEM 75 #define kern_addr_valid(addr) (1) 76 #else 77 #define kern_addr_valid(kaddr) (0) 78 #endif 79 80 /* 81 * This is how much memory in addition to the memory covered up to 82 * and including _end we need mapped initially. 83 * We need: 84 * (KERNEL_IMAGE_SIZE/4096) / 1024 pages (worst case, non PAE) 85 * (KERNEL_IMAGE_SIZE/4096) / 512 + 4 pages (worst case for PAE) 86 * 87 * Modulo rounding, each megabyte assigned here requires a kilobyte of 88 * memory, which is currently unreclaimed. 89 * 90 * This should be a multiple of a page. 91 * 92 * KERNEL_IMAGE_SIZE should be greater than pa(_end) 93 * and small than max_low_pfn, otherwise will waste some page table entries 94 */ 95 #if PTRS_PER_PMD > 1 96 #define PAGE_TABLE_SIZE(pages) (((pages) / PTRS_PER_PMD) + PTRS_PER_PGD) 97 #else 98 #define PAGE_TABLE_SIZE(pages) ((pages) / PTRS_PER_PGD) 99 #endif 100 101 /* 102 * Number of possible pages in the lowmem region. 103 * 104 * We shift 2 by 31 instead of 1 by 32 to the left in order to avoid a 105 * gas warning about overflowing shift count when gas has been compiled 106 * with only a host target support using a 32-bit type for internal 107 * representation. 108 */ 109 #define LOWMEM_PAGES ((((2<<31) - __PAGE_OFFSET) >> PAGE_SHIFT)) 110 111 #endif /* _ASM_X86_PGTABLE_32_H */ 112