| b.liu | e958203 | 2025-04-17 19:18:16 +0800 | [diff] [blame^] | 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 */ |