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Linux kernel mirror (for testing)
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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#include <asm/fixmap.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_32KB
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#ifdef CONFIG_PAGE_SIZE_64KB
93#define PGD_ORDER 0
94#define PUD_ORDER aieeee_attempt_to_allocate_pud
95#define PMD_ORDER 0
96#define PTE_ORDER 0
97#endif
98
99#define PTRS_PER_PGD ((PAGE_SIZE << PGD_ORDER) / sizeof(pgd_t))
100#define PTRS_PER_PMD ((PAGE_SIZE << PMD_ORDER) / sizeof(pmd_t))
101#define PTRS_PER_PTE ((PAGE_SIZE << PTE_ORDER) / sizeof(pte_t))
102
103#if PGDIR_SIZE >= TASK_SIZE
104#define USER_PTRS_PER_PGD (1)
105#else
106#define USER_PTRS_PER_PGD (TASK_SIZE / PGDIR_SIZE)
107#endif
108#define FIRST_USER_ADDRESS 0UL
109
110#define VMALLOC_START MAP_BASE
111#define VMALLOC_END \
112 (VMALLOC_START + PTRS_PER_PGD * PTRS_PER_PMD * PTRS_PER_PTE * PAGE_SIZE)
113#if defined(CONFIG_MODULES) && defined(KBUILD_64BIT_SYM32) && \
114 VMALLOC_START != CKSSEG
115/* Load modules into 32bit-compatible segment. */
116#define MODULE_START CKSSEG
117#define MODULE_END (FIXADDR_START-2*PAGE_SIZE)
118extern pgd_t module_pg_dir[PTRS_PER_PGD];
119#endif
120
121#define pte_ERROR(e) \
122 printk("%s:%d: bad pte %016lx.\n", __FILE__, __LINE__, pte_val(e))
123#define pmd_ERROR(e) \
124 printk("%s:%d: bad pmd %016lx.\n", __FILE__, __LINE__, pmd_val(e))
125#define pgd_ERROR(e) \
126 printk("%s:%d: bad pgd %016lx.\n", __FILE__, __LINE__, pgd_val(e))
127
128extern pte_t invalid_pte_table[PTRS_PER_PTE];
129extern pte_t empty_bad_page_table[PTRS_PER_PTE];
130extern pmd_t invalid_pmd_table[PTRS_PER_PMD];
131extern pmd_t empty_bad_pmd_table[PTRS_PER_PMD];
132
133/*
134 * Empty pgd/pmd entries point to the invalid_pte_table.
135 */
136static inline int pmd_none(pmd_t pmd)
137{
138 return pmd_val(pmd) == (unsigned long) invalid_pte_table;
139}
140
141#define pmd_bad(pmd) (pmd_val(pmd) & ~PAGE_MASK)
142
143static inline int pmd_present(pmd_t pmd)
144{
145 return pmd_val(pmd) != (unsigned long) invalid_pte_table;
146}
147
148static inline void pmd_clear(pmd_t *pmdp)
149{
150 pmd_val(*pmdp) = ((unsigned long) invalid_pte_table);
151}
152
153/*
154 * Empty pud entries point to the invalid_pmd_table.
155 */
156static inline int pud_none(pud_t pud)
157{
158 return pud_val(pud) == (unsigned long) invalid_pmd_table;
159}
160
161static inline int pud_bad(pud_t pud)
162{
163 return pud_val(pud) & ~PAGE_MASK;
164}
165
166static inline int pud_present(pud_t pud)
167{
168 return pud_val(pud) != (unsigned long) invalid_pmd_table;
169}
170
171static inline void pud_clear(pud_t *pudp)
172{
173 pud_val(*pudp) = ((unsigned long) invalid_pmd_table);
174}
175
176#define pte_page(x) pfn_to_page(pte_pfn(x))
177
178#ifdef CONFIG_CPU_VR41XX
179#define pte_pfn(x) ((unsigned long)((x).pte >> (PAGE_SHIFT + 2)))
180#define pfn_pte(pfn, prot) __pte(((pfn) << (PAGE_SHIFT + 2)) | pgprot_val(prot))
181#else
182#define pte_pfn(x) ((unsigned long)((x).pte >> PAGE_SHIFT))
183#define pfn_pte(pfn, prot) __pte(((pfn) << PAGE_SHIFT) | pgprot_val(prot))
184#endif
185
186#define __pgd_offset(address) pgd_index(address)
187#define __pud_offset(address) (((address) >> PUD_SHIFT) & (PTRS_PER_PUD-1))
188#define __pmd_offset(address) pmd_index(address)
189
190/* to find an entry in a kernel page-table-directory */
191#ifdef MODULE_START
192#define pgd_offset_k(address) \
193 ((address) >= MODULE_START ? module_pg_dir : pgd_offset(&init_mm, 0UL))
194#else
195#define pgd_offset_k(address) pgd_offset(&init_mm, 0UL)
196#endif
197
198#define pgd_index(address) (((address) >> PGDIR_SHIFT) & (PTRS_PER_PGD-1))
199#define pmd_index(address) (((address) >> PMD_SHIFT) & (PTRS_PER_PMD-1))
200
201/* to find an entry in a page-table-directory */
202#define pgd_offset(mm, addr) ((mm)->pgd + pgd_index(addr))
203
204static inline unsigned long pud_page_vaddr(pud_t pud)
205{
206 return pud_val(pud);
207}
208#define pud_phys(pud) virt_to_phys((void *)pud_val(pud))
209#define pud_page(pud) (pfn_to_page(pud_phys(pud) >> PAGE_SHIFT))
210
211/* Find an entry in the second-level page table.. */
212static inline pmd_t *pmd_offset(pud_t * pud, unsigned long address)
213{
214 return (pmd_t *) pud_page_vaddr(*pud) + pmd_index(address);
215}
216
217/* Find an entry in the third-level page table.. */
218#define __pte_offset(address) \
219 (((address) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
220#define pte_offset(dir, address) \
221 ((pte_t *) pmd_page_vaddr(*(dir)) + __pte_offset(address))
222#define pte_offset_kernel(dir, address) \
223 ((pte_t *) pmd_page_vaddr(*(dir)) + __pte_offset(address))
224#define pte_offset_map(dir, address) \
225 ((pte_t *)page_address(pmd_page(*(dir))) + __pte_offset(address))
226#define pte_offset_map_nested(dir, address) \
227 ((pte_t *)page_address(pmd_page(*(dir))) + __pte_offset(address))
228#define pte_unmap(pte) ((void)(pte))
229#define pte_unmap_nested(pte) ((void)(pte))
230
231/*
232 * Initialize a new pgd / pmd table with invalid pointers.
233 */
234extern void pgd_init(unsigned long page);
235extern void pmd_init(unsigned long page, unsigned long pagetable);
236
237/*
238 * Non-present pages: high 24 bits are offset, next 8 bits type,
239 * low 32 bits zero.
240 */
241static inline pte_t mk_swap_pte(unsigned long type, unsigned long offset)
242{ pte_t pte; pte_val(pte) = (type << 32) | (offset << 40); return pte; }
243
244#define __swp_type(x) (((x).val >> 32) & 0xff)
245#define __swp_offset(x) ((x).val >> 40)
246#define __swp_entry(type, offset) ((swp_entry_t) { pte_val(mk_swap_pte((type), (offset))) })
247#define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
248#define __swp_entry_to_pte(x) ((pte_t) { (x).val })
249
250/*
251 * Bits 0, 4, 6, and 7 are taken. Let's leave bits 1, 2, 3, and 5 alone to
252 * make things easier, and only use the upper 56 bits for the page offset...
253 */
254#define PTE_FILE_MAX_BITS 56
255
256#define pte_to_pgoff(_pte) ((_pte).pte >> 8)
257#define pgoff_to_pte(off) ((pte_t) { ((off) << 8) | _PAGE_FILE })
258
259#endif /* _ASM_PGTABLE_64_H */