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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#ifdef CONFIG_PAGE_SIZE_64KB
20#include <asm-generic/pgtable-nopmd.h>
21#else
22#include <asm-generic/pgtable-nopud.h>
23#endif
24
25/*
26 * Each address space has 2 4K pages as its page directory, giving 1024
27 * (== PTRS_PER_PGD) 8 byte pointers to pmd tables. Each pmd table is a
28 * single 4K page, giving 512 (== PTRS_PER_PMD) 8 byte pointers to page
29 * tables. Each page table is also a single 4K page, giving 512 (==
30 * PTRS_PER_PTE) 8 byte ptes. Each pud entry is initialized to point to
31 * invalid_pmd_table, each pmd entry is initialized to point to
32 * invalid_pte_table, each pte is initialized to 0. When memory is low,
33 * and a pmd table or a page table allocation fails, empty_bad_pmd_table
34 * and empty_bad_page_table is returned back to higher layer code, so
35 * that the failure is recognized later on. Linux does not seem to
36 * handle these failures very well though. The empty_bad_page_table has
37 * invalid pte entries in it, to force page faults.
38 *
39 * Kernel mappings: kernel mappings are held in the swapper_pg_table.
40 * The layout is identical to userspace except it's indexed with the
41 * fault address - VMALLOC_START.
42 */
43
44
45/* PGDIR_SHIFT determines what a third-level page table entry can map */
46#ifdef __PAGETABLE_PMD_FOLDED
47#define PGDIR_SHIFT (PAGE_SHIFT + PAGE_SHIFT + PTE_ORDER - 3)
48#else
49
50/* PMD_SHIFT determines the size of the area a second-level page table can map */
51#define PMD_SHIFT (PAGE_SHIFT + (PAGE_SHIFT + PTE_ORDER - 3))
52#define PMD_SIZE (1UL << PMD_SHIFT)
53#define PMD_MASK (~(PMD_SIZE-1))
54
55
56#define PGDIR_SHIFT (PMD_SHIFT + (PAGE_SHIFT + PMD_ORDER - 3))
57#endif
58#define PGDIR_SIZE (1UL << PGDIR_SHIFT)
59#define PGDIR_MASK (~(PGDIR_SIZE-1))
60
61/*
62 * For 4kB page size we use a 3 level page tree and an 8kB pud, which
63 * permits us mapping 40 bits of virtual address space.
64 *
65 * We used to implement 41 bits by having an order 1 pmd level but that seemed
66 * rather pointless.
67 *
68 * For 8kB page size we use a 3 level page tree which permits a total of
69 * 8TB of address space. Alternatively a 33-bit / 8GB organization using
70 * two levels would be easy to implement.
71 *
72 * For 16kB page size we use a 2 level page tree which permits a total of
73 * 36 bits of virtual address space. We could add a third level but it seems
74 * like at the moment there's no need for this.
75 *
76 * For 64kB page size we use a 2 level page table tree for a total of 42 bits
77 * of virtual address space.
78 */
79#ifdef CONFIG_PAGE_SIZE_4KB
80#define PGD_ORDER 1
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_8KB
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#ifdef CONFIG_PAGE_SIZE_16KB
92#define PGD_ORDER 0
93#define PUD_ORDER aieeee_attempt_to_allocate_pud
94#define PMD_ORDER 0
95#define PTE_ORDER 0
96#endif
97#ifdef CONFIG_PAGE_SIZE_32KB
98#define PGD_ORDER 0
99#define PUD_ORDER aieeee_attempt_to_allocate_pud
100#define PMD_ORDER 0
101#define PTE_ORDER 0
102#endif
103#ifdef CONFIG_PAGE_SIZE_64KB
104#define PGD_ORDER 0
105#define PUD_ORDER aieeee_attempt_to_allocate_pud
106#define PMD_ORDER aieeee_attempt_to_allocate_pmd
107#define PTE_ORDER 0
108#endif
109
110#define PTRS_PER_PGD ((PAGE_SIZE << PGD_ORDER) / sizeof(pgd_t))
111#ifndef __PAGETABLE_PMD_FOLDED
112#define PTRS_PER_PMD ((PAGE_SIZE << PMD_ORDER) / sizeof(pmd_t))
113#endif
114#define PTRS_PER_PTE ((PAGE_SIZE << PTE_ORDER) / sizeof(pte_t))
115
116#if PGDIR_SIZE >= TASK_SIZE
117#define USER_PTRS_PER_PGD (1)
118#else
119#define USER_PTRS_PER_PGD (TASK_SIZE / PGDIR_SIZE)
120#endif
121#define FIRST_USER_ADDRESS 0UL
122
123#define VMALLOC_START MAP_BASE
124#define VMALLOC_END \
125 (VMALLOC_START + \
126 min(PTRS_PER_PGD * PTRS_PER_PMD * PTRS_PER_PTE * PAGE_SIZE, \
127 (1UL << cpu_vmbits)) - (1UL << 32))
128
129#if defined(CONFIG_MODULES) && defined(KBUILD_64BIT_SYM32) && \
130 VMALLOC_START != CKSSEG
131/* Load modules into 32bit-compatible segment. */
132#define MODULE_START CKSSEG
133#define MODULE_END (FIXADDR_START-2*PAGE_SIZE)
134#endif
135
136#define pte_ERROR(e) \
137 printk("%s:%d: bad pte %016lx.\n", __FILE__, __LINE__, pte_val(e))
138#ifndef __PAGETABLE_PMD_FOLDED
139#define pmd_ERROR(e) \
140 printk("%s:%d: bad pmd %016lx.\n", __FILE__, __LINE__, pmd_val(e))
141#endif
142#define pgd_ERROR(e) \
143 printk("%s:%d: bad pgd %016lx.\n", __FILE__, __LINE__, pgd_val(e))
144
145extern pte_t invalid_pte_table[PTRS_PER_PTE];
146extern pte_t empty_bad_page_table[PTRS_PER_PTE];
147
148
149#ifndef __PAGETABLE_PMD_FOLDED
150/*
151 * For 3-level pagetables we defines these ourselves, for 2-level the
152 * definitions are supplied by <asm-generic/pgtable-nopmd.h>.
153 */
154typedef struct { unsigned long pmd; } pmd_t;
155#define pmd_val(x) ((x).pmd)
156#define __pmd(x) ((pmd_t) { (x) } )
157
158
159extern pmd_t invalid_pmd_table[PTRS_PER_PMD];
160extern pmd_t empty_bad_pmd_table[PTRS_PER_PMD];
161#endif
162
163/*
164 * Empty pgd/pmd entries point to the invalid_pte_table.
165 */
166static inline int pmd_none(pmd_t pmd)
167{
168 return pmd_val(pmd) == (unsigned long) invalid_pte_table;
169}
170
171#define pmd_bad(pmd) (pmd_val(pmd) & ~PAGE_MASK)
172
173static inline int pmd_present(pmd_t pmd)
174{
175 return pmd_val(pmd) != (unsigned long) invalid_pte_table;
176}
177
178static inline void pmd_clear(pmd_t *pmdp)
179{
180 pmd_val(*pmdp) = ((unsigned long) invalid_pte_table);
181}
182#ifndef __PAGETABLE_PMD_FOLDED
183
184/*
185 * Empty pud entries point to the invalid_pmd_table.
186 */
187static inline int pud_none(pud_t pud)
188{
189 return pud_val(pud) == (unsigned long) invalid_pmd_table;
190}
191
192static inline int pud_bad(pud_t pud)
193{
194 return pud_val(pud) & ~PAGE_MASK;
195}
196
197static inline int pud_present(pud_t pud)
198{
199 return pud_val(pud) != (unsigned long) invalid_pmd_table;
200}
201
202static inline void pud_clear(pud_t *pudp)
203{
204 pud_val(*pudp) = ((unsigned long) invalid_pmd_table);
205}
206#endif
207
208#define pte_page(x) pfn_to_page(pte_pfn(x))
209
210#ifdef CONFIG_CPU_VR41XX
211#define pte_pfn(x) ((unsigned long)((x).pte >> (PAGE_SHIFT + 2)))
212#define pfn_pte(pfn, prot) __pte(((pfn) << (PAGE_SHIFT + 2)) | pgprot_val(prot))
213#else
214#define pte_pfn(x) ((unsigned long)((x).pte >> _PFN_SHIFT))
215#define pfn_pte(pfn, prot) __pte(((pfn) << _PFN_SHIFT) | pgprot_val(prot))
216#endif
217
218#define __pgd_offset(address) pgd_index(address)
219#define __pud_offset(address) (((address) >> PUD_SHIFT) & (PTRS_PER_PUD-1))
220#define __pmd_offset(address) pmd_index(address)
221
222/* to find an entry in a kernel page-table-directory */
223#define pgd_offset_k(address) pgd_offset(&init_mm, address)
224
225#define pgd_index(address) (((address) >> PGDIR_SHIFT) & (PTRS_PER_PGD-1))
226#define pmd_index(address) (((address) >> PMD_SHIFT) & (PTRS_PER_PMD-1))
227
228/* to find an entry in a page-table-directory */
229#define pgd_offset(mm, addr) ((mm)->pgd + pgd_index(addr))
230
231#ifndef __PAGETABLE_PMD_FOLDED
232static inline unsigned long pud_page_vaddr(pud_t pud)
233{
234 return pud_val(pud);
235}
236#define pud_phys(pud) virt_to_phys((void *)pud_val(pud))
237#define pud_page(pud) (pfn_to_page(pud_phys(pud) >> PAGE_SHIFT))
238
239/* Find an entry in the second-level page table.. */
240static inline pmd_t *pmd_offset(pud_t * pud, unsigned long address)
241{
242 return (pmd_t *) pud_page_vaddr(*pud) + pmd_index(address);
243}
244#endif
245
246/* Find an entry in the third-level page table.. */
247#define __pte_offset(address) \
248 (((address) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
249#define pte_offset(dir, address) \
250 ((pte_t *) pmd_page_vaddr(*(dir)) + __pte_offset(address))
251#define pte_offset_kernel(dir, address) \
252 ((pte_t *) pmd_page_vaddr(*(dir)) + __pte_offset(address))
253#define pte_offset_map(dir, address) \
254 ((pte_t *)page_address(pmd_page(*(dir))) + __pte_offset(address))
255#define pte_offset_map_nested(dir, address) \
256 ((pte_t *)page_address(pmd_page(*(dir))) + __pte_offset(address))
257#define pte_unmap(pte) ((void)(pte))
258#define pte_unmap_nested(pte) ((void)(pte))
259
260/*
261 * Initialize a new pgd / pmd table with invalid pointers.
262 */
263extern void pgd_init(unsigned long page);
264extern void pmd_init(unsigned long page, unsigned long pagetable);
265
266/*
267 * Non-present pages: high 24 bits are offset, next 8 bits type,
268 * low 32 bits zero.
269 */
270static inline pte_t mk_swap_pte(unsigned long type, unsigned long offset)
271{ pte_t pte; pte_val(pte) = (type << 32) | (offset << 40); return pte; }
272
273#define __swp_type(x) (((x).val >> 32) & 0xff)
274#define __swp_offset(x) ((x).val >> 40)
275#define __swp_entry(type, offset) ((swp_entry_t) { pte_val(mk_swap_pte((type), (offset))) })
276#define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
277#define __swp_entry_to_pte(x) ((pte_t) { (x).val })
278
279/*
280 * Bits 0, 4, 6, and 7 are taken. Let's leave bits 1, 2, 3, and 5 alone to
281 * make things easier, and only use the upper 56 bits for the page offset...
282 */
283#define PTE_FILE_MAX_BITS 56
284
285#define pte_to_pgoff(_pte) ((_pte).pte >> 8)
286#define pgoff_to_pte(off) ((pte_t) { ((off) << 8) | _PAGE_FILE })
287
288#endif /* _ASM_PGTABLE_64_H */