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1/*
2 * This file is subject to the terms and conditions of the GNU General Public
3 * License. See the file "COPYING" in the main directory of this archive
4 * for more details.
5 *
6 * Copyright (C) 1994, 95, 96, 97, 98, 99, 2000, 2003 Ralf Baechle
7 * Copyright (C) 1999, 2000, 2001 Silicon Graphics, Inc.
8 */
9#ifndef _ASM_PGTABLE_64_H
10#define _ASM_PGTABLE_64_H
11
12#include <linux/config.h>
13#include <linux/linkage.h>
14
15#include <asm/addrspace.h>
16#include <asm/page.h>
17#include <asm/cachectl.h>
18
19#include <asm-generic/pgtable-nopud.h>
20
21/*
22 * Each address space has 2 4K pages as its page directory, giving 1024
23 * (== PTRS_PER_PGD) 8 byte pointers to pmd tables. Each pmd table is a
24 * single 4K page, giving 512 (== PTRS_PER_PMD) 8 byte pointers to page
25 * tables. Each page table is also a single 4K page, giving 512 (==
26 * PTRS_PER_PTE) 8 byte ptes. Each pud entry is initialized to point to
27 * invalid_pmd_table, each pmd entry is initialized to point to
28 * invalid_pte_table, each pte is initialized to 0. When memory is low,
29 * and a pmd table or a page table allocation fails, empty_bad_pmd_table
30 * and empty_bad_page_table is returned back to higher layer code, so
31 * that the failure is recognized later on. Linux does not seem to
32 * handle these failures very well though. The empty_bad_page_table has
33 * invalid pte entries in it, to force page faults.
34 *
35 * Kernel mappings: kernel mappings are held in the swapper_pg_table.
36 * The layout is identical to userspace except it's indexed with the
37 * fault address - VMALLOC_START.
38 */
39
40/* PMD_SHIFT determines the size of the area a second-level page table can map */
41#define PMD_SHIFT (PAGE_SHIFT + (PAGE_SHIFT + PTE_ORDER - 3))
42#define PMD_SIZE (1UL << PMD_SHIFT)
43#define PMD_MASK (~(PMD_SIZE-1))
44
45/* PGDIR_SHIFT determines what a third-level page table entry can map */
46#define PGDIR_SHIFT (PMD_SHIFT + (PAGE_SHIFT + PMD_ORDER - 3))
47#define PGDIR_SIZE (1UL << PGDIR_SHIFT)
48#define PGDIR_MASK (~(PGDIR_SIZE-1))
49
50/*
51 * For 4kB page size we use a 3 level page tree and an 8kB pud, which
52 * permits us mapping 40 bits of virtual address space.
53 *
54 * We used to implement 41 bits by having an order 1 pmd level but that seemed
55 * rather pointless.
56 *
57 * For 8kB page size we use a 3 level page tree which permits a total of
58 * 8TB of address space. Alternatively a 33-bit / 8GB organization using
59 * two levels would be easy to implement.
60 *
61 * For 16kB page size we use a 2 level page tree which permits a total of
62 * 36 bits of virtual address space. We could add a third level but it seems
63 * like at the moment there's no need for this.
64 *
65 * For 64kB page size we use a 2 level page table tree for a total of 42 bits
66 * of virtual address space.
67 */
68#ifdef CONFIG_PAGE_SIZE_4KB
69#define PGD_ORDER 1
70#define PUD_ORDER aieeee_attempt_to_allocate_pud
71#define PMD_ORDER 0
72#define PTE_ORDER 0
73#endif
74#ifdef CONFIG_PAGE_SIZE_8KB
75#define PGD_ORDER 0
76#define PUD_ORDER aieeee_attempt_to_allocate_pud
77#define PMD_ORDER 0
78#define PTE_ORDER 0
79#endif
80#ifdef CONFIG_PAGE_SIZE_16KB
81#define PGD_ORDER 0
82#define PUD_ORDER aieeee_attempt_to_allocate_pud
83#define PMD_ORDER 0
84#define PTE_ORDER 0
85#endif
86#ifdef CONFIG_PAGE_SIZE_64KB
87#define PGD_ORDER 0
88#define PUD_ORDER aieeee_attempt_to_allocate_pud
89#define PMD_ORDER 0
90#define PTE_ORDER 0
91#endif
92
93#define PTRS_PER_PGD ((PAGE_SIZE << PGD_ORDER) / sizeof(pgd_t))
94#define PTRS_PER_PMD ((PAGE_SIZE << PMD_ORDER) / sizeof(pmd_t))
95#define PTRS_PER_PTE ((PAGE_SIZE << PTE_ORDER) / sizeof(pte_t))
96
97#define USER_PTRS_PER_PGD (TASK_SIZE / PGDIR_SIZE)
98#define FIRST_USER_ADDRESS 0
99
100#define VMALLOC_START MAP_BASE
101#define VMALLOC_END \
102 (VMALLOC_START + PTRS_PER_PGD * PTRS_PER_PMD * PTRS_PER_PTE * PAGE_SIZE)
103
104#define pte_ERROR(e) \
105 printk("%s:%d: bad pte %016lx.\n", __FILE__, __LINE__, pte_val(e))
106#define pmd_ERROR(e) \
107 printk("%s:%d: bad pmd %016lx.\n", __FILE__, __LINE__, pmd_val(e))
108#define pgd_ERROR(e) \
109 printk("%s:%d: bad pgd %016lx.\n", __FILE__, __LINE__, pgd_val(e))
110
111extern pte_t invalid_pte_table[PTRS_PER_PTE];
112extern pte_t empty_bad_page_table[PTRS_PER_PTE];
113extern pmd_t invalid_pmd_table[PTRS_PER_PMD];
114extern pmd_t empty_bad_pmd_table[PTRS_PER_PMD];
115
116/*
117 * Empty pgd/pmd entries point to the invalid_pte_table.
118 */
119static inline int pmd_none(pmd_t pmd)
120{
121 return pmd_val(pmd) == (unsigned long) invalid_pte_table;
122}
123
124#define pmd_bad(pmd) (pmd_val(pmd) & ~PAGE_MASK)
125
126static inline int pmd_present(pmd_t pmd)
127{
128 return pmd_val(pmd) != (unsigned long) invalid_pte_table;
129}
130
131static inline void pmd_clear(pmd_t *pmdp)
132{
133 pmd_val(*pmdp) = ((unsigned long) invalid_pte_table);
134}
135
136/*
137 * Empty pud entries point to the invalid_pmd_table.
138 */
139static inline int pud_none(pud_t pud)
140{
141 return pud_val(pud) == (unsigned long) invalid_pmd_table;
142}
143
144static inline int pud_bad(pud_t pud)
145{
146 return pud_val(pud) & ~PAGE_MASK;
147}
148
149static inline int pud_present(pud_t pud)
150{
151 return pud_val(pud) != (unsigned long) invalid_pmd_table;
152}
153
154static inline void pud_clear(pud_t *pudp)
155{
156 pud_val(*pudp) = ((unsigned long) invalid_pmd_table);
157}
158
159#define pte_page(x) pfn_to_page(pte_pfn(x))
160
161#ifdef CONFIG_CPU_VR41XX
162#define pte_pfn(x) ((unsigned long)((x).pte >> (PAGE_SHIFT + 2)))
163#define pfn_pte(pfn, prot) __pte(((pfn) << (PAGE_SHIFT + 2)) | pgprot_val(prot))
164#else
165#define pte_pfn(x) ((unsigned long)((x).pte >> PAGE_SHIFT))
166#define pfn_pte(pfn, prot) __pte(((pfn) << PAGE_SHIFT) | pgprot_val(prot))
167#endif
168
169#define __pgd_offset(address) pgd_index(address)
170#define __pud_offset(address) (((address) >> PUD_SHIFT) & (PTRS_PER_PUD-1))
171#define __pmd_offset(address) pmd_index(address)
172
173/* to find an entry in a kernel page-table-directory */
174#define pgd_offset_k(address) pgd_offset(&init_mm, 0)
175
176#define pgd_index(address) (((address) >> PGDIR_SHIFT) & (PTRS_PER_PGD-1))
177#define pmd_index(address) (((address) >> PMD_SHIFT) & (PTRS_PER_PMD-1))
178
179/* to find an entry in a page-table-directory */
180#define pgd_offset(mm,addr) ((mm)->pgd + pgd_index(addr))
181
182static inline unsigned long pud_page(pud_t pud)
183{
184 return pud_val(pud);
185}
186
187/* Find an entry in the second-level page table.. */
188static inline pmd_t *pmd_offset(pud_t * pud, unsigned long address)
189{
190 return (pmd_t *) pud_page(*pud) + pmd_index(address);
191}
192
193/* Find an entry in the third-level page table.. */
194#define __pte_offset(address) \
195 (((address) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
196#define pte_offset(dir, address) \
197 ((pte_t *) (pmd_page_kernel(*dir)) + __pte_offset(address))
198#define pte_offset_kernel(dir, address) \
199 ((pte_t *) pmd_page_kernel(*(dir)) + __pte_offset(address))
200#define pte_offset_map(dir, address) \
201 ((pte_t *)page_address(pmd_page(*(dir))) + __pte_offset(address))
202#define pte_offset_map_nested(dir, address) \
203 ((pte_t *)page_address(pmd_page(*(dir))) + __pte_offset(address))
204#define pte_unmap(pte) ((void)(pte))
205#define pte_unmap_nested(pte) ((void)(pte))
206
207/*
208 * Initialize a new pgd / pmd table with invalid pointers.
209 */
210extern void pgd_init(unsigned long page);
211extern void pmd_init(unsigned long page, unsigned long pagetable);
212
213/*
214 * Non-present pages: high 24 bits are offset, next 8 bits type,
215 * low 32 bits zero.
216 */
217static inline pte_t mk_swap_pte(unsigned long type, unsigned long offset)
218{ pte_t pte; pte_val(pte) = (type << 32) | (offset << 40); return pte; }
219
220#define __swp_type(x) (((x).val >> 32) & 0xff)
221#define __swp_offset(x) ((x).val >> 40)
222#define __swp_entry(type,offset) ((swp_entry_t) { pte_val(mk_swap_pte((type),(offset))) })
223#define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
224#define __swp_entry_to_pte(x) ((pte_t) { (x).val })
225
226/*
227 * Bits 0, 1, 2, 7 and 8 are taken, split up the 32 bits of offset
228 * into this range:
229 */
230#define PTE_FILE_MAX_BITS 32
231
232#define pte_to_pgoff(_pte) \
233 ((((_pte).pte >> 3) & 0x1f ) + (((_pte).pte >> 9) << 6 ))
234
235#define pgoff_to_pte(off) \
236 ((pte_t) { (((off) & 0x1f) << 3) + (((off) >> 6) << 9) + _PAGE_FILE })
237
238#endif /* _ASM_PGTABLE_64_H */