include/asm-mips/pgtable-64.h

   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/config.h>
  13 #include <linux/linkage.h>
  14
  15 #include <asm/addrspace.h>
  16 #include <asm/page.h>
  17 #include <asm/cachectl.h>
  18
  19 /*
  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  *
  33  * Kernel mappings: kernel mappings are held in the swapper_pg_table.
  34  * The layout is identical to userspace except it's indexed with the
  35  * fault address - VMALLOC_START.
  36  */
  37
  38 /* PMD_SHIFT determines the size of the area a second-level page table can map */
  39 #define PMD_SHIFT       (PAGE_SHIFT + (PAGE_SHIFT - 3))
  40 #define PMD_SIZE        (1UL << PMD_SHIFT)
  41 #define PMD_MASK        (~(PMD_SIZE-1))
  42
  43 /* PGDIR_SHIFT determines what a third-level page table entry can map */
  44 #define PGDIR_SHIFT     (PMD_SHIFT + (PAGE_SHIFT + 1 - 3))
  45 #define PGDIR_SIZE      (1UL << PGDIR_SHIFT)
  46 #define PGDIR_MASK      (~(PGDIR_SIZE-1))
  47
  48 /*
  49  * For 4kB page size we use a 3 level page tree and a 8kB pmd and pgds which
  50  * permits us mapping 40 bits of virtual address space.
  51  *
  52  * We used to implement 41 bits by having an order 1 pmd level but that seemed
  53  * rather pointless.
  54  *
  55  * For 8kB page size we use a 3 level page tree which permits a total of
  56  * 8TB of address space.  Alternatively a 33-bit / 8GB organization using
  57  * two levels would be easy to implement.
  58  *
  59  * For 16kB page size we use a 2 level page tree which permits a total of
  60  * 36 bits of virtual address space.  We could add a third leve. but it seems
  61  * like at the moment there's no need for this.
  62  *
  63  * For 64kB page size we use a 2 level page table tree for a total of 42 bits
  64  * of virtual address space.
  65  */
  66 #ifdef CONFIG_PAGE_SIZE_4KB
  67 #define PGD_ORDER               1
  68 #define PMD_ORDER               0
  69 #define PTE_ORDER               0
  70 #endif
  71 #ifdef CONFIG_PAGE_SIZE_8KB
  72 #define PGD_ORDER               0
  73 #define PMD_ORDER               0
  74 #define PTE_ORDER               0
  75 #endif
  76 #ifdef CONFIG_PAGE_SIZE_16KB
  77 #define PGD_ORDER               0
  78 #define PMD_ORDER               0
  79 #define PTE_ORDER               0
  80 #endif
  81 #ifdef CONFIG_PAGE_SIZE_64KB
  82 #define PGD_ORDER               0
  83 #define PMD_ORDER               0
  84 #define PTE_ORDER               0
  85 #endif
  86
  87 #define PTRS_PER_PGD    ((PAGE_SIZE << PGD_ORDER) / sizeof(pgd_t))
  88 #define PTRS_PER_PMD    ((PAGE_SIZE << PMD_ORDER) / sizeof(pmd_t))
  89 #define PTRS_PER_PTE    ((PAGE_SIZE << PTE_ORDER) / sizeof(pte_t))
  90
  91 #define USER_PTRS_PER_PGD       (TASK_SIZE / PGDIR_SIZE)
  92 #define FIRST_USER_PGD_NR       0
  93
  94 #define VMALLOC_START           XKSEG
  95 #define VMALLOC_END     \
  96         (VMALLOC_START + PTRS_PER_PGD * PTRS_PER_PMD * PTRS_PER_PTE * PAGE_SIZE)
  97
  98 #define pte_ERROR(e) \
  99         printk("%s:%d: bad pte %016lx.\n", __FILE__, __LINE__, pte_val(e))
 100 #define pmd_ERROR(e) \
 101         printk("%s:%d: bad pmd %016lx.\n", __FILE__, __LINE__, pmd_val(e))
 102 #define pgd_ERROR(e) \
 103         printk("%s:%d: bad pgd %016lx.\n", __FILE__, __LINE__, pgd_val(e))
 104
 105 extern pte_t invalid_pte_table[PAGE_SIZE/sizeof(pte_t)];
 106 extern pte_t empty_bad_page_table[PAGE_SIZE/sizeof(pte_t)];
 107 extern pmd_t invalid_pmd_table[2*PAGE_SIZE/sizeof(pmd_t)];
 108 extern pmd_t empty_bad_pmd_table[2*PAGE_SIZE/sizeof(pmd_t)];
 109
 110 /*
 111  * Empty pmd entries point to the invalid_pte_table.
 112  */
 113 static inline int pmd_none(pmd_t pmd)
 114 {
 115         return pmd_val(pmd) == (unsigned long) invalid_pte_table;
 116 }
 117
 118 #define pmd_bad(pmd)            (pmd_val(pmd) & ~PAGE_MASK)
 119
 120 static inline int pmd_present(pmd_t pmd)
 121 {
 122         return pmd_val(pmd) != (unsigned long) invalid_pte_table;
 123 }
 124
 125 static inline void pmd_clear(pmd_t *pmdp)
 126 {
 127         pmd_val(*pmdp) = ((unsigned long) invalid_pte_table);
 128 }
 129
 130 /*
 131  * Empty pgd entries point to the invalid_pmd_table.
 132  */
 133 static inline int pgd_none(pgd_t pgd)
 134 {
 135         return pgd_val(pgd) == (unsigned long) invalid_pmd_table;
 136 }
 137
 138 #define pgd_bad(pgd)            (pgd_val(pgd) &~ PAGE_MASK)
 139
 140 static inline int pgd_present(pgd_t pgd)
 141 {
 142         return pgd_val(pgd) != (unsigned long) invalid_pmd_table;
 143 }
 144
 145 static inline void pgd_clear(pgd_t *pgdp)
 146 {
 147         pgd_val(*pgdp) = ((unsigned long) invalid_pmd_table);
 148 }
 149
 150 #define pte_page(x)             pfn_to_page((unsigned long)((pte_val(x) >> PAGE_SHIFT)))
 151 #ifdef CONFIG_CPU_VR41XX
 152 #define pte_pfn(x)              ((unsigned long)((x).pte >> (PAGE_SHIFT + 2)))
 153 #define pfn_pte(pfn, prot)      __pte(((pfn) << (PAGE_SHIFT + 2)) | pgprot_val(prot))
 154 #else
 155 #define pte_pfn(x)              ((unsigned long)((x).pte >> PAGE_SHIFT))
 156 #define pfn_pte(pfn, prot)      __pte(((pfn) << PAGE_SHIFT) | pgprot_val(prot))
 157 #endif
 158
 159 #define __pgd_offset(address)   pgd_index(address)
 160 #define page_pte(page) page_pte_prot(page, __pgprot(0))
 161
 162 /* to find an entry in a kernel page-table-directory */
 163 #define pgd_offset_k(address) pgd_offset(&init_mm, 0)
 164
 165 #define pgd_index(address)              ((address) >> PGDIR_SHIFT)
 166
 167 /* to find an entry in a page-table-directory */
 168 #define pgd_offset(mm,addr)     ((mm)->pgd + pgd_index(addr))
 169
 170 static inline unsigned long pgd_page(pgd_t pgd)
 171 {
 172         return pgd_val(pgd);
 173 }
 174
 175 /* Find an entry in the second-level page table.. */
 176 static inline pmd_t *pmd_offset(pgd_t * dir, unsigned long address)
 177 {
 178         return (pmd_t *) pgd_page(*dir) +
 179                ((address >> PMD_SHIFT) & (PTRS_PER_PMD - 1));
 180 }
 181
 182 /* Find an entry in the third-level page table.. */
 183 #define __pte_offset(address)                                           \
 184         (((address) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
 185 #define pte_offset(dir, address)                                        \
 186         ((pte_t *) (pmd_page_kernel(*dir)) + __pte_offset(address))
 187 #define pte_offset_kernel(dir, address)                                 \
 188         ((pte_t *) pmd_page_kernel(*(dir)) +  __pte_offset(address))
 189 #define pte_offset_map(dir, address)                                    \
 190         ((pte_t *)page_address(pmd_page(*(dir))) + __pte_offset(address))
 191 #define pte_offset_map_nested(dir, address)                             \
 192         ((pte_t *)page_address(pmd_page(*(dir))) + __pte_offset(address))
 193 #define pte_unmap(pte) ((void)(pte))
 194 #define pte_unmap_nested(pte) ((void)(pte))
 195
 196 /*
 197  * Initialize a new pgd / pmd table with invalid pointers.
 198  */
 199 extern void pgd_init(unsigned long page);
 200 extern void pmd_init(unsigned long page, unsigned long pagetable);
 201
 202 /*
 203  * Non-present pages:  high 24 bits are offset, next 8 bits type,
 204  * low 32 bits zero.
 205  */
 206 static inline pte_t mk_swap_pte(unsigned long type, unsigned long offset)
 207 { pte_t pte; pte_val(pte) = (type << 32) | (offset << 40); return pte; }
 208
 209 #define __swp_type(x)           (((x).val >> 32) & 0xff)
 210 #define __swp_offset(x)         ((x).val >> 40)
 211 #define __swp_entry(type,offset) ((swp_entry_t) { pte_val(mk_swap_pte((type),(offset))) })
 212 #define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
 213 #define __swp_entry_to_pte(x)   ((pte_t) { (x).val })
 214
 215 /*
 216  * Bits 0, 1, 2, 7 and 8 are taken, split up the 32 bits of offset
 217  * into this range:
 218  */
 219 #define PTE_FILE_MAX_BITS       32
 220
 221 #define pte_to_pgoff(_pte) \
 222         ((((_pte).pte >> 3) & 0x1f ) + (((_pte).pte >> 9) << 6 ))
 223
 224 #define pgoff_to_pte(off) \
 225         ((pte_t) { (((off) & 0x1f) << 3) + (((off) >> 6) << 9) + _PAGE_FILE })
 226
 227 #endif /* _ASM_PGTABLE_64_H */