File: /usr/src/linux/include/asm-arm/pgtable.h
1 /*
2 * linux/include/asm-arm/pgtable.h
3 *
4 * Copyright (C) 2000-2001 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/arch/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_none(pte) (!pte_val(pte))
79 #define pte_clear(ptep) set_pte((ptep), __pte(0))
80
81 #ifndef CONFIG_DISCONTIGMEM
82 #define pte_page(x) (mem_map + (pte_val((x)) >> PAGE_SHIFT) - \
83 (PHYS_OFFSET >> PAGE_SHIFT))
84 #else
85 /*
86 * I'm not happy with this - we needlessly convert a physical address
87 * to a virtual one, and then immediately back to a physical address,
88 * which, if __va and __pa are expensive causes twice the expense for
89 * zero gain. --rmk
90 */
91 #define pte_page(x) (virt_to_page(__va(pte_val((x)))))
92 #endif
93
94 #define pmd_none(pmd) (!pmd_val(pmd))
95 #define pmd_present(pmd) (pmd_val(pmd))
96 #define pmd_clear(pmdp) set_pmd(pmdp, __pmd(0))
97
98 /*
99 * Permanent address of a page. We never have highmem, so this is trivial.
100 */
101 #define page_address(page) ((page)->virtual)
102 #define pages_to_mb(x) ((x) >> (20 - PAGE_SHIFT))
103
104 /*
105 * Conversion functions: convert a page and protection to a page entry,
106 * and a page entry and page directory to the page they refer to.
107 */
108 static inline pte_t mk_pte_phys(unsigned long physpage, pgprot_t pgprot)
109 {
110 pte_t pte;
111 pte_val(pte) = physpage | pgprot_val(pgprot);
112 return pte;
113 }
114
115 #define mk_pte(page,pgprot) \
116 ({ \
117 pte_t __pte; \
118 pte_val(__pte) = __pa(page_address(page)) + \
119 pgprot_val(pgprot); \
120 __pte; \
121 })
122
123 /*
124 * The "pgd_xxx()" functions here are trivial for a folded two-level
125 * setup: the pgd is never bad, and a pmd always exists (as it's folded
126 * into the pgd entry)
127 */
128 #define pgd_none(pgd) (0)
129 #define pgd_bad(pgd) (0)
130 #define pgd_present(pgd) (1)
131 #define pgd_clear(pgdp)
132
133 #define page_pte_prot(page,prot) mk_pte(page, prot)
134 #define page_pte(page) mk_pte(page, __pgprot(0))
135
136 /* to find an entry in a page-table-directory */
137 #define pgd_index(addr) ((addr) >> PGDIR_SHIFT)
138 #define __pgd_offset(addr) pgd_index(addr)
139
140 #define pgd_offset(mm, addr) ((mm)->pgd+pgd_index(addr))
141
142 /* to find an entry in a kernel page-table-directory */
143 #define pgd_offset_k(addr) pgd_offset(&init_mm, addr)
144
145 /* Find an entry in the second-level page table.. */
146 #define pmd_offset(dir, addr) ((pmd_t *)(dir))
147
148 /* Find an entry in the third-level page table.. */
149 #define __pte_offset(addr) (((addr) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
150 #define pte_offset(dir, addr) ((pte_t *)pmd_page(*(dir)) + __pte_offset(addr))
151
152 #include <asm/proc/pgtable.h>
153
154 static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
155 {
156 pte_val(pte) = (pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot);
157 return pte;
158 }
159
160 extern pgd_t swapper_pg_dir[PTRS_PER_PGD];
161
162 /* Encode and decode a swap entry.
163 *
164 * We support up to 32GB of swap on 4k machines
165 */
166 #define SWP_TYPE(x) (((x).val >> 2) & 0x7f)
167 #define SWP_OFFSET(x) ((x).val >> 9)
168 #define SWP_ENTRY(type,offset) ((swp_entry_t) { ((type) << 2) | ((offset) << 9) })
169 #define pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
170 #define swp_entry_to_pte(swp) ((pte_t) { (swp).val })
171
172 /* Needs to be defined here and not in linux/mm.h, as it is arch dependent */
173 /* FIXME: this is not correct */
174 #define kern_addr_valid(addr) (1)
175
176 #include <asm-generic/pgtable.h>
177
178 #endif /* !__ASSEMBLY__ */
179
180 #endif /* _ASMARM_PGTABLE_H */
181