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
pgtable_cache_init(void)32 static inline void pgtable_cache_init(void) { }
check_pgt_cache(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
