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_SIZE64
117 #define USER_PTRS_PER_PGD (1)
118 #else
119 #define USER_PTRS_PER_PGD (TASK_SIZE64 / PGDIR_SIZE)
120 #endif
121 #define FIRST_USER_ADDRESS 0UL
122
123 /*
124 * TLB refill handlers also map the vmalloc area into xuseg. Avoid
125 * the first couple of pages so NULL pointer dereferences will still
126 * reliably trap.
127 */
128 #define VMALLOC_START (MAP_BASE + (2 * PAGE_SIZE))
129 #define VMALLOC_END \
130 (MAP_BASE + \
131 min(PTRS_PER_PGD * PTRS_PER_PMD * PTRS_PER_PTE * PAGE_SIZE, \
132 (1UL << cpu_vmbits)) - (1UL << 32))
133
134 #if defined(CONFIG_MODULES) && defined(KBUILD_64BIT_SYM32) && \
135 VMALLOC_START != CKSSEG
136 /* Load modules into 32bit-compatible segment. */
137 #define MODULE_START CKSSEG
138 #define MODULE_END (FIXADDR_START-2*PAGE_SIZE)
139 #endif
140
141 #define pte_ERROR(e) \
142 printk("%s:%d: bad pte %016lx.\n", __FILE__, __LINE__, pte_val(e))
143 #ifndef __PAGETABLE_PMD_FOLDED
144 #define pmd_ERROR(e) \
145 printk("%s:%d: bad pmd %016lx.\n", __FILE__, __LINE__, pmd_val(e))
146 #endif
147 #define pgd_ERROR(e) \
148 printk("%s:%d: bad pgd %016lx.\n", __FILE__, __LINE__, pgd_val(e))
149
150 extern pte_t invalid_pte_table[PTRS_PER_PTE];
151 extern pte_t empty_bad_page_table[PTRS_PER_PTE];
152
153
154 #ifndef __PAGETABLE_PMD_FOLDED
155 /*
156 * For 3-level pagetables we defines these ourselves, for 2-level the
157 * definitions are supplied by <asm-generic/pgtable-nopmd.h>.
158 */
159 typedef struct { unsigned long pmd; } pmd_t;
160 #define pmd_val(x) ((x).pmd)
161 #define __pmd(x) ((pmd_t) { (x) } )
162
163
164 extern pmd_t invalid_pmd_table[PTRS_PER_PMD];
165 extern pmd_t empty_bad_pmd_table[PTRS_PER_PMD];
166 #endif
167
168 /*
169 * Empty pgd/pmd entries point to the invalid_pte_table.
170 */
pmd_none(pmd_t pmd)171 static inline int pmd_none(pmd_t pmd)
172 {
173 return pmd_val(pmd) == (unsigned long) invalid_pte_table;
174 }
175
176 #define pmd_bad(pmd) (pmd_val(pmd) & ~PAGE_MASK)
177
pmd_present(pmd_t pmd)178 static inline int pmd_present(pmd_t pmd)
179 {
180 return pmd_val(pmd) != (unsigned long) invalid_pte_table;
181 }
182
pmd_clear(pmd_t * pmdp)183 static inline void pmd_clear(pmd_t *pmdp)
184 {
185 pmd_val(*pmdp) = ((unsigned long) invalid_pte_table);
186 }
187 #ifndef __PAGETABLE_PMD_FOLDED
188
189 /*
190 * Empty pud entries point to the invalid_pmd_table.
191 */
pud_none(pud_t pud)192 static inline int pud_none(pud_t pud)
193 {
194 return pud_val(pud) == (unsigned long) invalid_pmd_table;
195 }
196
pud_bad(pud_t pud)197 static inline int pud_bad(pud_t pud)
198 {
199 return pud_val(pud) & ~PAGE_MASK;
200 }
201
pud_present(pud_t pud)202 static inline int pud_present(pud_t pud)
203 {
204 return pud_val(pud) != (unsigned long) invalid_pmd_table;
205 }
206
pud_clear(pud_t * pudp)207 static inline void pud_clear(pud_t *pudp)
208 {
209 pud_val(*pudp) = ((unsigned long) invalid_pmd_table);
210 }
211 #endif
212
213 #define pte_page(x) pfn_to_page(pte_pfn(x))
214
215 #ifdef CONFIG_CPU_VR41XX
216 #define pte_pfn(x) ((unsigned long)((x).pte >> (PAGE_SHIFT + 2)))
217 #define pfn_pte(pfn, prot) __pte(((pfn) << (PAGE_SHIFT + 2)) | pgprot_val(prot))
218 #else
219 #define pte_pfn(x) ((unsigned long)((x).pte >> _PFN_SHIFT))
220 #define pfn_pte(pfn, prot) __pte(((pfn) << _PFN_SHIFT) | pgprot_val(prot))
221 #endif
222
223 #define __pgd_offset(address) pgd_index(address)
224 #define __pud_offset(address) (((address) >> PUD_SHIFT) & (PTRS_PER_PUD-1))
225 #define __pmd_offset(address) pmd_index(address)
226
227 /* to find an entry in a kernel page-table-directory */
228 #define pgd_offset_k(address) pgd_offset(&init_mm, address)
229
230 #define pgd_index(address) (((address) >> PGDIR_SHIFT) & (PTRS_PER_PGD-1))
231 #define pmd_index(address) (((address) >> PMD_SHIFT) & (PTRS_PER_PMD-1))
232
233 /* to find an entry in a page-table-directory */
234 #define pgd_offset(mm, addr) ((mm)->pgd + pgd_index(addr))
235
236 #ifndef __PAGETABLE_PMD_FOLDED
pud_page_vaddr(pud_t pud)237 static inline unsigned long pud_page_vaddr(pud_t pud)
238 {
239 return pud_val(pud);
240 }
241 #define pud_phys(pud) virt_to_phys((void *)pud_val(pud))
242 #define pud_page(pud) (pfn_to_page(pud_phys(pud) >> PAGE_SHIFT))
243
244 /* Find an entry in the second-level page table.. */
pmd_offset(pud_t * pud,unsigned long address)245 static inline pmd_t *pmd_offset(pud_t * pud, unsigned long address)
246 {
247 return (pmd_t *) pud_page_vaddr(*pud) + pmd_index(address);
248 }
249 #endif
250
251 /* Find an entry in the third-level page table.. */
252 #define __pte_offset(address) \
253 (((address) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
254 #define pte_offset(dir, address) \
255 ((pte_t *) pmd_page_vaddr(*(dir)) + __pte_offset(address))
256 #define pte_offset_kernel(dir, address) \
257 ((pte_t *) pmd_page_vaddr(*(dir)) + __pte_offset(address))
258 #define pte_offset_map(dir, address) \
259 ((pte_t *)page_address(pmd_page(*(dir))) + __pte_offset(address))
260 #define pte_unmap(pte) ((void)(pte))
261
262 /*
263 * Initialize a new pgd / pmd table with invalid pointers.
264 */
265 extern void pgd_init(unsigned long page);
266 extern void pmd_init(unsigned long page, unsigned long pagetable);
267
268 /*
269 * Non-present pages: high 24 bits are offset, next 8 bits type,
270 * low 32 bits zero.
271 */
mk_swap_pte(unsigned long type,unsigned long offset)272 static inline pte_t mk_swap_pte(unsigned long type, unsigned long offset)
273 { pte_t pte; pte_val(pte) = (type << 32) | (offset << 40); return pte; }
274
275 #define __swp_type(x) (((x).val >> 32) & 0xff)
276 #define __swp_offset(x) ((x).val >> 40)
277 #define __swp_entry(type, offset) ((swp_entry_t) { pte_val(mk_swap_pte((type), (offset))) })
278 #define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
279 #define __swp_entry_to_pte(x) ((pte_t) { (x).val })
280
281 /*
282 * Bits 0, 4, 6, and 7 are taken. Let's leave bits 1, 2, 3, and 5 alone to
283 * make things easier, and only use the upper 56 bits for the page offset...
284 */
285 #define PTE_FILE_MAX_BITS 56
286
287 #define pte_to_pgoff(_pte) ((_pte).pte >> 8)
288 #define pgoff_to_pte(off) ((pte_t) { ((off) << 8) | _PAGE_FILE })
289
290 #endif /* _ASM_PGTABLE_64_H */
291