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