release/src-rt-6.x.4708/linux/linux-2.6.36/arch/mips/include/asm/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 #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 /*
 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) && VMALLOC_START != CKSSEG
 135 /* Load modules into 32bit-compatible segment. */
 136 #define MODULE_START    CKSSEG
 137 #define MODULE_END      (FIXADDR_START-2*PAGE_SIZE)
 138 #endif
 139
 140 #define pte_ERROR(e) \
 141         printk("%s:%d: bad pte %016lx.\n", __FILE__, __LINE__, pte_val(e))
 142 #ifndef __PAGETABLE_PMD_FOLDED
 143 #define pmd_ERROR(e) \
 144         printk("%s:%d: bad pmd %016lx.\n", __FILE__, __LINE__, pmd_val(e))
 145 #endif
 146 #define pgd_ERROR(e) \
 147         printk("%s:%d: bad pgd %016lx.\n", __FILE__, __LINE__, pgd_val(e))
 148
 149 extern pte_t invalid_pte_table[PTRS_PER_PTE];
 150 extern pte_t empty_bad_page_table[PTRS_PER_PTE];
 151
 152
 153 #ifndef __PAGETABLE_PMD_FOLDED
 154 /*
 155  * For 3-level pagetables we defines these ourselves, for 2-level the
 156  * definitions are supplied by <asm-generic/pgtable-nopmd.h>.
 157  */
 158 typedef struct { unsigned long pmd; } pmd_t;
 159 #define pmd_val(x)      ((x).pmd)
 160 #define __pmd(x)        ((pmd_t) { (x) } )
 161
 162
 163 extern pmd_t invalid_pmd_table[PTRS_PER_PMD];
 164 extern pmd_t empty_bad_pmd_table[PTRS_PER_PMD];
 165 #endif
 166
 167 /*
 168  * Empty pgd/pmd entries point to the invalid_pte_table.
 169  */
 170 static inline int pmd_none(pmd_t pmd)
 171 {
 172         return pmd_val(pmd) == (unsigned long) invalid_pte_table;
 173 }
 174
 175 #define pmd_bad(pmd)            (pmd_val(pmd) & ~PAGE_MASK)
 176
 177 static inline int pmd_present(pmd_t pmd)
 178 {
 179         return pmd_val(pmd) != (unsigned long) invalid_pte_table;
 180 }
 181
 182 static inline void pmd_clear(pmd_t *pmdp)
 183 {
 184         pmd_val(*pmdp) = ((unsigned long) invalid_pte_table);
 185 }
 186 #ifndef __PAGETABLE_PMD_FOLDED
 187
 188 /*
 189  * Empty pud entries point to the invalid_pmd_table.
 190  */
 191 static inline int pud_none(pud_t pud)
 192 {
 193         return pud_val(pud) == (unsigned long) invalid_pmd_table;
 194 }
 195
 196 static inline int pud_bad(pud_t pud)
 197 {
 198         return pud_val(pud) & ~PAGE_MASK;
 199 }
 200
 201 static inline int pud_present(pud_t pud)
 202 {
 203         return pud_val(pud) != (unsigned long) invalid_pmd_table;
 204 }
 205
 206 static inline void pud_clear(pud_t *pudp)
 207 {
 208         pud_val(*pudp) = ((unsigned long) invalid_pmd_table);
 209 }
 210 #endif
 211
 212 #define pte_page(x)             pfn_to_page(pte_pfn(x))
 213
 214 #ifdef CONFIG_CPU_VR41XX
 215 #define pte_pfn(x)              ((unsigned long)((x).pte >> (PAGE_SHIFT + 2)))
 216 #define pfn_pte(pfn, prot)      __pte(((pfn) << (PAGE_SHIFT + 2)) | pgprot_val(prot))
 217 #else
 218 #define pte_pfn(x)              ((unsigned long)((x).pte >> _PFN_SHIFT))
 219 #define pfn_pte(pfn, prot)      __pte(((pfn) << _PFN_SHIFT) | pgprot_val(prot))
 220 #endif
 221
 222 #define __pgd_offset(address)   pgd_index(address)
 223 #define __pud_offset(address)   (((address) >> PUD_SHIFT) & (PTRS_PER_PUD-1))
 224 #define __pmd_offset(address)   pmd_index(address)
 225
 226 /* to find an entry in a kernel page-table-directory */
 227 #define pgd_offset_k(address) pgd_offset(&init_mm, address)
 228
 229 #define pgd_index(address)      (((address) >> PGDIR_SHIFT) & (PTRS_PER_PGD-1))
 230 #define pmd_index(address)      (((address) >> PMD_SHIFT) & (PTRS_PER_PMD-1))
 231
 232 /* to find an entry in a page-table-directory */
 233 #define pgd_offset(mm, addr)    ((mm)->pgd + pgd_index(addr))
 234
 235 #ifndef __PAGETABLE_PMD_FOLDED
 236 static inline unsigned long pud_page_vaddr(pud_t pud)
 237 {
 238         return pud_val(pud);
 239 }
 240 #define pud_phys(pud)           virt_to_phys((void *)pud_val(pud))
 241 #define pud_page(pud)           (pfn_to_page(pud_phys(pud) >> PAGE_SHIFT))
 242
 243 /* Find an entry in the second-level page table.. */
 244 static inline pmd_t *pmd_offset(pud_t * pud, unsigned long address)
 245 {
 246         return (pmd_t *) pud_page_vaddr(*pud) + pmd_index(address);
 247 }
 248 #endif
 249
 250 /* Find an entry in the third-level page table.. */
 251 #define __pte_offset(address)                                           \
 252         (((address) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
 253 #define pte_offset(dir, address)                                        \
 254         ((pte_t *) pmd_page_vaddr(*(dir)) + __pte_offset(address))
 255 #define pte_offset_kernel(dir, address)                                 \
 256         ((pte_t *) pmd_page_vaddr(*(dir)) + __pte_offset(address))
 257 #define pte_offset_map(dir, address)                                    \
 258         ((pte_t *)page_address(pmd_page(*(dir))) + __pte_offset(address))
 259 #define pte_offset_map_nested(dir, address)                             \
 260         ((pte_t *)page_address(pmd_page(*(dir))) + __pte_offset(address))
 261 #define pte_unmap(pte) ((void)(pte))
 262 #define pte_unmap_nested(pte) ((void)(pte))
 263
 264 /*
 265  * Initialize a new pgd / pmd table with invalid pointers.
 266  */
 267 extern void pgd_init(unsigned long page);
 268 extern void pmd_init(unsigned long page, unsigned long pagetable);
 269
 270 /*
 271  * Non-present pages:  high 24 bits are offset, next 8 bits type,
 272  * low 32 bits zero.
 273  */
 274 static inline pte_t mk_swap_pte(unsigned long type, unsigned long offset)
 275 { pte_t pte; pte_val(pte) = (type << 32) | (offset << 40); return pte; }
 276
 277 #define __swp_type(x)           (((x).val >> 32) & 0xff)
 278 #define __swp_offset(x)         ((x).val >> 40)
 279 #define __swp_entry(type, offset) ((swp_entry_t) { pte_val(mk_swap_pte((type), (offset))) })
 280 #define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
 281 #define __swp_entry_to_pte(x)   ((pte_t) { (x).val })
 282
 283 /*
 284  * Bits 0, 4, 6, and 7 are taken. Let's leave bits 1, 2, 3, and 5 alone to
 285  * make things easier, and only use the upper 56 bits for the page offset...
 286  */
 287 #define PTE_FILE_MAX_BITS       56
 288
 289 #define pte_to_pgoff(_pte)      ((_pte).pte >> 8)
 290 #define pgoff_to_pte(off)       ((pte_t) { ((off) << 8) | _PAGE_FILE })
 291
 292 #endif /* _ASM_PGTABLE_64_H */