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/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_64KB
  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
  93 #define PTRS_PER_PGD    ((PAGE_SIZE << PGD_ORDER) / sizeof(pgd_t))
  94 #define PTRS_PER_PMD    ((PAGE_SIZE << PMD_ORDER) / sizeof(pmd_t))
  95 #define PTRS_PER_PTE    ((PAGE_SIZE << PTE_ORDER) / sizeof(pte_t))
  96
  97 #if PGDIR_SIZE >= TASK_SIZE
  98 #define USER_PTRS_PER_PGD       (1)
  99 #else
 100 #define USER_PTRS_PER_PGD       (TASK_SIZE / PGDIR_SIZE)
 101 #endif
 102 #define FIRST_USER_ADDRESS      0UL
 103
 104 #define VMALLOC_START           MAP_BASE
 105 #define VMALLOC_END     \
 106         (VMALLOC_START + PTRS_PER_PGD * PTRS_PER_PMD * PTRS_PER_PTE * PAGE_SIZE)
 107 #if defined(CONFIG_MODULES) && defined(KBUILD_64BIT_SYM32) && \
 108         VMALLOC_START != CKSSEG
 109 /* Load modules into 32bit-compatible segment. */
 110 #define MODULE_START    CKSSEG
 111 #define MODULE_END      (FIXADDR_START-2*PAGE_SIZE)
 112 extern pgd_t module_pg_dir[PTRS_PER_PGD];
 113 #endif
 114
 115 #define pte_ERROR(e) \
 116         printk("%s:%d: bad pte %016lx.\n", __FILE__, __LINE__, pte_val(e))
 117 #define pmd_ERROR(e) \
 118         printk("%s:%d: bad pmd %016lx.\n", __FILE__, __LINE__, pmd_val(e))
 119 #define pgd_ERROR(e) \
 120         printk("%s:%d: bad pgd %016lx.\n", __FILE__, __LINE__, pgd_val(e))
 121
 122 extern pte_t invalid_pte_table[PTRS_PER_PTE];
 123 extern pte_t empty_bad_page_table[PTRS_PER_PTE];
 124 extern pmd_t invalid_pmd_table[PTRS_PER_PMD];
 125 extern pmd_t empty_bad_pmd_table[PTRS_PER_PMD];
 126
 127 /*
 128  * Empty pgd/pmd entries point to the invalid_pte_table.
 129  */
 130 static inline int pmd_none(pmd_t pmd)
 131 {
 132         return pmd_val(pmd) == (unsigned long) invalid_pte_table;
 133 }
 134
 135 #define pmd_bad(pmd)            (pmd_val(pmd) & ~PAGE_MASK)
 136
 137 static inline int pmd_present(pmd_t pmd)
 138 {
 139         return pmd_val(pmd) != (unsigned long) invalid_pte_table;
 140 }
 141
 142 static inline void pmd_clear(pmd_t *pmdp)
 143 {
 144         pmd_val(*pmdp) = ((unsigned long) invalid_pte_table);
 145 }
 146
 147 /*
 148  * Empty pud entries point to the invalid_pmd_table.
 149  */
 150 static inline int pud_none(pud_t pud)
 151 {
 152         return pud_val(pud) == (unsigned long) invalid_pmd_table;
 153 }
 154
 155 static inline int pud_bad(pud_t pud)
 156 {
 157         return pud_val(pud) & ~PAGE_MASK;
 158 }
 159
 160 static inline int pud_present(pud_t pud)
 161 {
 162         return pud_val(pud) != (unsigned long) invalid_pmd_table;
 163 }
 164
 165 static inline void pud_clear(pud_t *pudp)
 166 {
 167         pud_val(*pudp) = ((unsigned long) invalid_pmd_table);
 168 }
 169
 170 #define pte_page(x)             pfn_to_page(pte_pfn(x))
 171
 172 #ifdef CONFIG_CPU_VR41XX
 173 #define pte_pfn(x)              ((unsigned long)((x).pte >> (PAGE_SHIFT + 2)))
 174 #define pfn_pte(pfn, prot)      __pte(((pfn) << (PAGE_SHIFT + 2)) | pgprot_val(prot))
 175 #else
 176 #define pte_pfn(x)              ((unsigned long)((x).pte >> PAGE_SHIFT))
 177 #define pfn_pte(pfn, prot)      __pte(((pfn) << PAGE_SHIFT) | pgprot_val(prot))
 178 #endif
 179
 180 #define __pgd_offset(address)   pgd_index(address)
 181 #define __pud_offset(address)   (((address) >> PUD_SHIFT) & (PTRS_PER_PUD-1))
 182 #define __pmd_offset(address)   pmd_index(address)
 183
 184 /* to find an entry in a kernel page-table-directory */
 185 #ifdef MODULE_START
 186 #define pgd_offset_k(address) \
 187         ((address) >= MODULE_START ? module_pg_dir : pgd_offset(&init_mm, 0UL))
 188 #else
 189 #define pgd_offset_k(address) pgd_offset(&init_mm, 0UL)
 190 #endif
 191
 192 #define pgd_index(address)      (((address) >> PGDIR_SHIFT) & (PTRS_PER_PGD-1))
 193 #define pmd_index(address)      (((address) >> PMD_SHIFT) & (PTRS_PER_PMD-1))
 194
 195 /* to find an entry in a page-table-directory */
 196 #define pgd_offset(mm, addr)    ((mm)->pgd + pgd_index(addr))
 197
 198 static inline unsigned long pud_page_vaddr(pud_t pud)
 199 {
 200         return pud_val(pud);
 201 }
 202 #define pud_phys(pud)           virt_to_phys((void *)pud_val(pud))
 203 #define pud_page(pud)           (pfn_to_page(pud_phys(pud) >> PAGE_SHIFT))
 204
 205 /* Find an entry in the second-level page table.. */
 206 static inline pmd_t *pmd_offset(pud_t * pud, unsigned long address)
 207 {
 208         return (pmd_t *) pud_page_vaddr(*pud) + pmd_index(address);
 209 }
 210
 211 /* Find an entry in the third-level page table.. */
 212 #define __pte_offset(address)                                           \
 213         (((address) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
 214 #define pte_offset(dir, address)                                        \
 215         ((pte_t *) pmd_page_vaddr(*(dir)) + __pte_offset(address))
 216 #define pte_offset_kernel(dir, address)                                 \
 217         ((pte_t *) pmd_page_vaddr(*(dir)) + __pte_offset(address))
 218 #define pte_offset_map(dir, address)                                    \
 219         ((pte_t *)page_address(pmd_page(*(dir))) + __pte_offset(address))
 220 #define pte_offset_map_nested(dir, address)                             \
 221         ((pte_t *)page_address(pmd_page(*(dir))) + __pte_offset(address))
 222 #define pte_unmap(pte) ((void)(pte))
 223 #define pte_unmap_nested(pte) ((void)(pte))
 224
 225 /*
 226  * Initialize a new pgd / pmd table with invalid pointers.
 227  */
 228 extern void pgd_init(unsigned long page);
 229 extern void pmd_init(unsigned long page, unsigned long pagetable);
 230
 231 /*
 232  * Non-present pages:  high 24 bits are offset, next 8 bits type,
 233  * low 32 bits zero.
 234  */
 235 static inline pte_t mk_swap_pte(unsigned long type, unsigned long offset)
 236 { pte_t pte; pte_val(pte) = (type << 32) | (offset << 40); return pte; }
 237
 238 #define __swp_type(x)           (((x).val >> 32) & 0xff)
 239 #define __swp_offset(x)         ((x).val >> 40)
 240 #define __swp_entry(type, offset) ((swp_entry_t) { pte_val(mk_swap_pte((type), (offset))) })
 241 #define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
 242 #define __swp_entry_to_pte(x)   ((pte_t) { (x).val })
 243
 244 /*
 245  * Bits 0, 4, 6, and 7 are taken. Let's leave bits 1, 2, 3, and 5 alone to
 246  * make things easier, and only use the upper 56 bits for the page offset...
 247  */
 248 #define PTE_FILE_MAX_BITS       56
 249
 250 #define pte_to_pgoff(_pte)      ((_pte).pte >> 8)
 251 #define pgoff_to_pte(off)       ((pte_t) { ((off) << 8) | _PAGE_FILE })
 252
 253 #endif /* _ASM_PGTABLE_64_H */