1 /*
2 * linux/include/asm-arm/pgtable.h
3 *
4 * Copyright (C) 2000-2002 Russell King
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 */
10 #ifndef _ASMARM_PGTABLE_H
11 #define _ASMARM_PGTABLE_H
12
13 #include <linux/config.h>
14 #include <asm/memory.h>
15 #include <asm/proc-fns.h>
16
17 /*
18 * PMD_SHIFT determines the size of the area a second-level page table can map
19 * PGDIR_SHIFT determines what a third-level page table entry can map
20 */
21 #define PMD_SHIFT 20
22 #define PGDIR_SHIFT 20
23
24 #define LIBRARY_TEXT_START 0x0c000000
25
26 #ifndef __ASSEMBLY__
27 extern void __pte_error(const char *file, int line, unsigned long val);
28 extern void __pmd_error(const char *file, int line, unsigned long val);
29 extern void __pgd_error(const char *file, int line, unsigned long val);
30
31 #define pte_ERROR(pte) __pte_error(__FILE__, __LINE__, pte_val(pte))
32 #define pmd_ERROR(pmd) __pmd_error(__FILE__, __LINE__, pmd_val(pmd))
33 #define pgd_ERROR(pgd) __pgd_error(__FILE__, __LINE__, pgd_val(pgd))
34 #endif /* !__ASSEMBLY__ */
35
36 #define PMD_SIZE (1UL << PMD_SHIFT)
37 #define PMD_MASK (~(PMD_SIZE-1))
38 #define PGDIR_SIZE (1UL << PGDIR_SHIFT)
39 #define PGDIR_MASK (~(PGDIR_SIZE-1))
40
41 #define FIRST_USER_PGD_NR 1
42 #define USER_PTRS_PER_PGD ((TASK_SIZE/PGDIR_SIZE) - FIRST_USER_PGD_NR)
43
44 /*
45 * The table below defines the page protection levels that we insert into our
46 * Linux page table version. These get translated into the best that the
47 * architecture can perform. Note that on most ARM hardware:
48 * 1) We cannot do execute protection
49 * 2) If we could do execute protection, then read is implied
50 * 3) write implies read permissions
51 */
52 #define __P000 PAGE_NONE
53 #define __P001 PAGE_READONLY
54 #define __P010 PAGE_COPY
55 #define __P011 PAGE_COPY
56 #define __P100 PAGE_READONLY
57 #define __P101 PAGE_READONLY
58 #define __P110 PAGE_COPY
59 #define __P111 PAGE_COPY
60
61 #define __S000 PAGE_NONE
62 #define __S001 PAGE_READONLY
63 #define __S010 PAGE_SHARED
64 #define __S011 PAGE_SHARED
65 #define __S100 PAGE_READONLY
66 #define __S101 PAGE_READONLY
67 #define __S110 PAGE_SHARED
68 #define __S111 PAGE_SHARED
69
70 #ifndef __ASSEMBLY__
71 /*
72 * ZERO_PAGE is a global shared page that is always zero: used
73 * for zero-mapped memory areas etc..
74 */
75 extern struct page *empty_zero_page;
76 #define ZERO_PAGE(vaddr) (empty_zero_page)
77
78 #define pte_pfn(pte) (pte_val(pte) >> PAGE_SHIFT)
79 #define pfn_pte(pfn,prot) (__pte(((pfn) << PAGE_SHIFT) | pgprot_val(prot)))
80
81 #define pte_none(pte) (!pte_val(pte))
82 #define pte_clear(ptep) set_pte((ptep), __pte(0))
83
84 #define pte_page(pte) (pfn_to_page(pte_pfn(pte)))
85
86 #define pmd_none(pmd) (!pmd_val(pmd))
87 #define pmd_present(pmd) (pmd_val(pmd))
88 #define pmd_clear(pmdp) set_pmd(pmdp, __pmd(0))
89
90 /*
91 * Permanent address of a page. We never have highmem, so this is trivial.
92 */
93 #define pages_to_mb(x) ((x) >> (20 - PAGE_SHIFT))
94
95 /*
96 * Conversion functions: convert a page and protection to a page entry,
97 * and a page entry and page directory to the page they refer to.
98 */
mk_pte_phys(unsigned long physpage,pgprot_t pgprot)99 static inline pte_t mk_pte_phys(unsigned long physpage, pgprot_t pgprot)
100 {
101 pte_t pte;
102 pte_val(pte) = physpage | pgprot_val(pgprot);
103 return pte;
104 }
105
106 #define mk_pte(page,prot) pfn_pte(page_to_pfn(page),prot)
107
108 /*
109 * The "pgd_xxx()" functions here are trivial for a folded two-level
110 * setup: the pgd is never bad, and a pmd always exists (as it's folded
111 * into the pgd entry)
112 */
113 #define pgd_none(pgd) (0)
114 #define pgd_bad(pgd) (0)
115 #define pgd_present(pgd) (1)
116 #define pgd_clear(pgdp) do { } while (0)
117
118 #define page_pte_prot(page,prot) mk_pte(page, prot)
119 #define page_pte(page) mk_pte(page, __pgprot(0))
120
121 /* to find an entry in a page-table-directory */
122 #define pgd_index(addr) ((addr) >> PGDIR_SHIFT)
123 #define __pgd_offset(addr) pgd_index(addr)
124
125 #define pgd_offset(mm, addr) ((mm)->pgd+pgd_index(addr))
126
127 /* to find an entry in a kernel page-table-directory */
128 #define pgd_offset_k(addr) pgd_offset(&init_mm, addr)
129
130 /* Find an entry in the second-level page table.. */
131 #define pmd_offset(dir, addr) ((pmd_t *)(dir))
132
133 /* Find an entry in the third-level page table.. */
134 #define __pte_offset(addr) (((addr) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
135 #define pte_offset(dir, addr) ((pte_t *)pmd_page(*(dir)) + __pte_offset(addr))
136
137 #include <asm/proc/pgtable.h>
138
pte_modify(pte_t pte,pgprot_t newprot)139 static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
140 {
141 pte_val(pte) = (pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot);
142 return pte;
143 }
144
145 extern pgd_t swapper_pg_dir[PTRS_PER_PGD];
146
147 /* Encode and decode a swap entry.
148 *
149 * We support up to 32GB of swap on 4k machines
150 */
151 #define SWP_TYPE(x) (((x).val >> 2) & 0x7f)
152 #define SWP_OFFSET(x) ((x).val >> 9)
153 #define SWP_ENTRY(type,offset) ((swp_entry_t) { ((type) << 2) | ((offset) << 9) })
154 #define pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
155 #define swp_entry_to_pte(swp) ((pte_t) { (swp).val })
156
157 /* Needs to be defined here and not in linux/mm.h, as it is arch dependent */
158 /* FIXME: this is not correct */
159 #define kern_addr_valid(addr) (1)
160
161 #include <asm-generic/pgtable.h>
162
163 extern void pgtable_cache_init(void);
164
165 /*
166 * remap a physical address `phys' of size `size' with page protection `prot'
167 * into virtual address `from'
168 */
169 #define io_remap_page_range(from,phys,size,prot) \
170 remap_page_range(from,phys,size,prot)
171
172 #endif /* !__ASSEMBLY__ */
173
174 #endif /* _ASMARM_PGTABLE_H */
175