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