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
6 * Copyright (C) 1994, 95, 96, 97, 98, 99, 2000, 2003 Ralf Baechle
7 * Copyright (C) 1999, 2000, 2001 Silicon Graphics, Inc.
9 #ifndef _ASM_PGTABLE_64_H
10 #define _ASM_PGTABLE_64_H
12 #include <linux/config.h>
13 #include <linux/linkage.h>
15 #include <asm/addrspace.h>
17 #include <asm/cachectl.h>
20 * Each address space has 2 4K pages as its page directory, giving 1024
21 * (== PTRS_PER_PGD) 8 byte pointers to pmd tables. Each pmd table is a
22 * pair of 4K pages, giving 1024 (== PTRS_PER_PMD) 8 byte pointers to
23 * page tables. Each page table is a single 4K page, giving 512 (==
24 * PTRS_PER_PTE) 8 byte ptes. Each pgde is initialized to point to
25 * invalid_pmd_table, each pmde is initialized to point to
26 * invalid_pte_table, each pte is initialized to 0. When memory is low,
27 * and a pmd table or a page table allocation fails, empty_bad_pmd_table
28 * and empty_bad_page_table is returned back to higher layer code, so
29 * that the failure is recognized later on. Linux does not seem to
30 * handle these failures very well though. The empty_bad_page_table has
31 * invalid pte entries in it, to force page faults.
32 * Vmalloc handling: vmalloc uses swapper_pg_dir[0] (returned by
33 * pgd_offset_k), which is initalized to point to kpmdtbl. kpmdtbl is
34 * the only single page pmd in the system. kpmdtbl entries point into
35 * kptbl[] array. We reserve 1 << PGD_ORDER pages to hold the
36 * vmalloc range translations, which the fault handler looks at.
39 /* PMD_SHIFT determines the size of the area a second-level page table can map */
40 #define PMD_SHIFT (PAGE_SHIFT + (PAGE_SHIFT - 3))
41 #define PMD_SIZE (1UL << PMD_SHIFT)
42 #define PMD_MASK (~(PMD_SIZE-1))
44 /* PGDIR_SHIFT determines what a third-level page table entry can map */
45 #define PGDIR_SHIFT (PMD_SHIFT + (PAGE_SHIFT + 1 - 3))
46 #define PGDIR_SIZE (1UL << PGDIR_SHIFT)
47 #define PGDIR_MASK (~(PGDIR_SIZE-1))
50 * For 4kB page size we use a 3 level page tree and a 8kB pmd and pgds which
51 * permits us mapping 40 bits of virtual address space.
53 * We used to implement 41 bits by having an order 1 pmd level but that seemed
56 * For 16kB page size we use a 2 level page tree which permit a total of
57 * 36 bits of virtual address space. We could add a third leve. but it seems
58 * like at the moment there's no need for this.
60 * For 64kB page size we use a 2 level page table tree for a total of 42 bits
61 * of virtual address space.
63 #ifdef CONFIG_PAGE_SIZE_4KB
68 #ifdef CONFIG_PAGE_SIZE_16KB
73 #ifdef CONFIG_PAGE_SIZE_64KB
79 #define PTRS_PER_PGD ((PAGE_SIZE << PGD_ORDER) / sizeof(pgd_t))
80 #define PTRS_PER_PMD ((PAGE_SIZE << PMD_ORDER) / sizeof(pmd_t))
81 #define PTRS_PER_PTE ((PAGE_SIZE << PTE_ORDER) / sizeof(pte_t))
83 #define USER_PTRS_PER_PGD (TASK_SIZE / PGDIR_SIZE)
84 #define FIRST_USER_PGD_NR 0
86 #define VMALLOC_START XKSEG
88 (VMALLOC_START + ((1 << PGD_ORDER) * PTRS_PER_PTE * PAGE_SIZE))
90 #define pte_ERROR(e) \
91 printk("%s:%d: bad pte %016lx.\n", __FILE__, __LINE__, pte_val(e))
92 #define pmd_ERROR(e) \
93 printk("%s:%d: bad pmd %016lx.\n", __FILE__, __LINE__, pmd_val(e))
94 #define pgd_ERROR(e) \
95 printk("%s:%d: bad pgd %016lx.\n", __FILE__, __LINE__, pgd_val(e))
97 extern pte_t invalid_pte_table[PAGE_SIZE/sizeof(pte_t)];
98 extern pte_t empty_bad_page_table[PAGE_SIZE/sizeof(pte_t)];
99 extern pmd_t invalid_pmd_table[2*PAGE_SIZE/sizeof(pmd_t)];
100 extern pmd_t empty_bad_pmd_table[2*PAGE_SIZE/sizeof(pmd_t)];
103 * Empty pmd entries point to the invalid_pte_table.
105 static inline int pmd_none(pmd_t pmd)
107 return pmd_val(pmd) == (unsigned long) invalid_pte_table;
110 #define pmd_bad(pmd) (pmd_val(pmd) & ~PAGE_MASK)
112 static inline int pmd_present(pmd_t pmd)
114 return pmd_val(pmd) != (unsigned long) invalid_pte_table;
117 static inline void pmd_clear(pmd_t *pmdp)
119 pmd_val(*pmdp) = ((unsigned long) invalid_pte_table);
123 * Empty pgd entries point to the invalid_pmd_table.
125 static inline int pgd_none(pgd_t pgd)
127 return pgd_val(pgd) == (unsigned long) invalid_pmd_table;
130 #define pgd_bad(pgd) (pgd_val(pgd) &~ PAGE_MASK)
132 static inline int pgd_present(pgd_t pgd)
134 return pgd_val(pgd) != (unsigned long) invalid_pmd_table;
137 static inline void pgd_clear(pgd_t *pgdp)
139 pgd_val(*pgdp) = ((unsigned long) invalid_pmd_table);
142 #define pte_page(x) pfn_to_page((unsigned long)((pte_val(x) >> PAGE_SHIFT)))
143 #ifdef CONFIG_CPU_VR41XX
144 #define pte_pfn(x) ((unsigned long)((x).pte >> (PAGE_SHIFT + 2)))
145 #define pfn_pte(pfn, prot) __pte(((pfn) << (PAGE_SHIFT + 2)) | pgprot_val(prot))
147 #define pte_pfn(x) ((unsigned long)((x).pte >> PAGE_SHIFT))
148 #define pfn_pte(pfn, prot) __pte(((pfn) << PAGE_SHIFT) | pgprot_val(prot))
152 * Bits 0, 1, 2, 7 and 8 are taken, split up the 27 bits of offset
155 #define pte_to_pgoff(_pte) \
156 ((((_pte).pte >> 3) & 0x1f ) + (((_pte).pte >> 9) << 6 ))
158 #define pgoff_to_pte(off) \
159 ((pte_t) { (((off) & 0x1f) << 3) + (((off) >> 6) << 9) + _PAGE_FILE })
161 #define __pgd_offset(address) pgd_index(address)
162 #define page_pte(page) page_pte_prot(page, __pgprot(0))
164 /* to find an entry in a kernel page-table-directory */
165 #define pgd_offset_k(address) pgd_offset(&init_mm, 0)
167 #define pgd_index(address) ((address) >> PGDIR_SHIFT)
169 /* to find an entry in a page-table-directory */
170 #define pgd_offset(mm,addr) ((mm)->pgd + pgd_index(addr))
172 static inline unsigned long pgd_page(pgd_t pgd)
177 /* Find an entry in the second-level page table.. */
178 static inline pmd_t *pmd_offset(pgd_t * dir, unsigned long address)
180 return (pmd_t *) pgd_page(*dir) +
181 ((address >> PMD_SHIFT) & (PTRS_PER_PMD - 1));
184 /* Find an entry in the third-level page table.. */
185 #define __pte_offset(address) \
186 (((address) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
187 #define pte_offset(dir, address) \
188 ((pte_t *) (pmd_page_kernel(*dir)) + __pte_offset(address))
189 #define pte_offset_kernel(dir, address) \
190 ((pte_t *) pmd_page_kernel(*(dir)) + __pte_offset(address))
191 #define pte_offset_map(dir, address) \
192 ((pte_t *)page_address(pmd_page(*(dir))) + __pte_offset(address))
193 #define pte_offset_map_nested(dir, address) \
194 ((pte_t *)page_address(pmd_page(*(dir))) + __pte_offset(address))
195 #define pte_unmap(pte) ((void)(pte))
196 #define pte_unmap_nested(pte) ((void)(pte))
199 * Initialize a new pgd / pmd table with invalid pointers.
201 extern void pgd_init(unsigned long page);
202 extern void pmd_init(unsigned long page, unsigned long pagetable);
205 * Non-present pages: high 24 bits are offset, next 8 bits type,
208 static inline pte_t mk_swap_pte(unsigned long type, unsigned long offset)
209 { pte_t pte; pte_val(pte) = (type << 32) | (offset << 40); return pte; }
211 #define __swp_type(x) (((x).val >> 32) & 0xff)
212 #define __swp_offset(x) ((x).val >> 40)
213 #define __swp_entry(type,offset) ((swp_entry_t) { pte_val(mk_swap_pte((type),(offset))) })
214 #define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
215 #define __swp_entry_to_pte(x) ((pte_t) { (x).val })
217 typedef pte_t *pte_addr_t;
220 * Used for the b0rked handling of kernel pagetables on the 64-bit kernel.
222 extern pte_t kptbl[(PAGE_SIZE << PGD_ORDER)/sizeof(pte_t)];
223 extern pmd_t kpmdtbl[PTRS_PER_PMD];
225 #endif /* _ASM_PGTABLE_64_H */