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/compiler.h>
  13 #include <linux/linkage.h>
  14
  15 #include <asm/addrspace.h>
  16 #include <asm/page.h>
  17 #include <asm/cachectl.h>
  18 #include <asm/fixmap.h>
  19
  20 #if defined(CONFIG_PAGE_SIZE_64KB) && !defined(CONFIG_MIPS_VA_BITS_48)
  21 #include <asm-generic/pgtable-nopmd.h>
  22 #else
  23 #include <asm-generic/pgtable-nopud.h>
  24 #endif
  25
  26 /*
  27  * Each address space has 2 4K pages as its page directory, giving 1024
  28  * (== PTRS_PER_PGD) 8 byte pointers to pmd tables. Each pmd table is a
  29  * single 4K page, giving 512 (== PTRS_PER_PMD) 8 byte pointers to page
  30  * tables. Each page table is also a single 4K page, giving 512 (==
  31  * PTRS_PER_PTE) 8 byte ptes. Each pud entry is initialized to point to
  32  * invalid_pmd_table, each pmd entry is initialized to point to
  33  * invalid_pte_table, each pte is initialized to 0. When memory is low,
  34  * and a pmd table or a page table allocation fails, empty_bad_pmd_table
  35  * and empty_bad_page_table is returned back to higher layer code, so
  36  * that the failure is recognized later on. Linux does not seem to
  37  * handle these failures very well though. The empty_bad_page_table has
  38  * invalid pte entries in it, to force page faults.
  39  *
  40  * Kernel mappings: kernel mappings are held in the swapper_pg_table.
  41  * The layout is identical to userspace except it's indexed with the
  42  * fault address - VMALLOC_START.
  43  */
  44
  45
  46 /* PGDIR_SHIFT determines what a third-level page table entry can map */
  47 #ifdef __PAGETABLE_PMD_FOLDED
  48 #define PGDIR_SHIFT     (PAGE_SHIFT + PAGE_SHIFT + PTE_ORDER - 3)
  49 #else
  50
  51 /* PMD_SHIFT determines the size of the area a second-level page table can map */
  52 #define PMD_SHIFT       (PAGE_SHIFT + (PAGE_SHIFT + PTE_ORDER - 3))
  53 #define PMD_SIZE        (1UL << PMD_SHIFT)
  54 #define PMD_MASK        (~(PMD_SIZE-1))
  55
  56
  57 #define PGDIR_SHIFT     (PMD_SHIFT + (PAGE_SHIFT + PMD_ORDER - 3))
  58 #endif
  59 #define PGDIR_SIZE      (1UL << PGDIR_SHIFT)
  60 #define PGDIR_MASK      (~(PGDIR_SIZE-1))
  61
  62 /*
  63  * For 4kB page size we use a 3 level page tree and an 8kB pud, which
  64  * permits us mapping 40 bits of virtual address space.
  65  *
  66  * We used to implement 41 bits by having an order 1 pmd level but that seemed
  67  * rather pointless.
  68  *
  69  * For 8kB page size we use a 3 level page tree which permits a total of
  70  * 8TB of address space.  Alternatively a 33-bit / 8GB organization using
  71  * two levels would be easy to implement.
  72  *
  73  * For 16kB page size we use a 2 level page tree which permits a total of
  74  * 36 bits of virtual address space.  We could add a third level but it seems
  75  * like at the moment there's no need for this.
  76  *
  77  * For 64kB page size we use a 2 level page table tree for a total of 42 bits
  78  * of virtual address space.
  79  */
  80 #ifdef CONFIG_PAGE_SIZE_4KB
  81 #define PGD_ORDER               1
  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_8KB
  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 #ifdef CONFIG_PAGE_SIZE_16KB
  93 #ifdef CONFIG_MIPS_VA_BITS_48
  94 #define PGD_ORDER               1
  95 #else
  96 #define PGD_ORDER               0
  97 #endif
  98 #define PUD_ORDER               aieeee_attempt_to_allocate_pud
  99 #define PMD_ORDER               0
 100 #define PTE_ORDER               0
 101 #endif
 102 #ifdef CONFIG_PAGE_SIZE_32KB
 103 #define PGD_ORDER               0
 104 #define PUD_ORDER               aieeee_attempt_to_allocate_pud
 105 #define PMD_ORDER               0
 106 #define PTE_ORDER               0
 107 #endif
 108 #ifdef CONFIG_PAGE_SIZE_64KB
 109 #define PGD_ORDER               0
 110 #define PUD_ORDER               aieeee_attempt_to_allocate_pud
 111 #ifdef CONFIG_MIPS_VA_BITS_48
 112 #define PMD_ORDER               0
 113 #else
 114 #define PMD_ORDER               aieeee_attempt_to_allocate_pmd
 115 #endif
 116 #define PTE_ORDER               0
 117 #endif
 118
 119 #define PTRS_PER_PGD    ((PAGE_SIZE << PGD_ORDER) / sizeof(pgd_t))
 120 #ifndef __PAGETABLE_PMD_FOLDED
 121 #define PTRS_PER_PMD    ((PAGE_SIZE << PMD_ORDER) / sizeof(pmd_t))
 122 #endif
 123 #define PTRS_PER_PTE    ((PAGE_SIZE << PTE_ORDER) / sizeof(pte_t))
 124
 125 #define USER_PTRS_PER_PGD       ((TASK_SIZE64 / PGDIR_SIZE)?(TASK_SIZE64 / PGDIR_SIZE):1)
 126 #define FIRST_USER_ADDRESS      0UL
 127
 128 /*
 129  * TLB refill handlers also map the vmalloc area into xuseg.  Avoid
 130  * the first couple of pages so NULL pointer dereferences will still
 131  * reliably trap.
 132  */
 133 #define VMALLOC_START           (MAP_BASE + (2 * PAGE_SIZE))
 134 #define VMALLOC_END     \
 135         (MAP_BASE + \
 136          min(PTRS_PER_PGD * PTRS_PER_PMD * PTRS_PER_PTE * PAGE_SIZE, \
 137              (1UL << cpu_vmbits)) - (1UL << 32))
 138
 139 #if defined(CONFIG_MODULES) && defined(KBUILD_64BIT_SYM32) && \
 140         VMALLOC_START != CKSSEG
 141 /* Load modules into 32bit-compatible segment. */
 142 #define MODULE_START    CKSSEG
 143 #define MODULE_END      (FIXADDR_START-2*PAGE_SIZE)
 144 #endif
 145
 146 #define pte_ERROR(e) \
 147         printk("%s:%d: bad pte %016lx.\n", __FILE__, __LINE__, pte_val(e))
 148 #ifndef __PAGETABLE_PMD_FOLDED
 149 #define pmd_ERROR(e) \
 150         printk("%s:%d: bad pmd %016lx.\n", __FILE__, __LINE__, pmd_val(e))
 151 #endif
 152 #define pgd_ERROR(e) \
 153         printk("%s:%d: bad pgd %016lx.\n", __FILE__, __LINE__, pgd_val(e))
 154
 155 extern pte_t invalid_pte_table[PTRS_PER_PTE];
 156 extern pte_t empty_bad_page_table[PTRS_PER_PTE];
 157
 158
 159 #ifndef __PAGETABLE_PMD_FOLDED
 160 /*
 161  * For 3-level pagetables we defines these ourselves, for 2-level the
 162  * definitions are supplied by <asm-generic/pgtable-nopmd.h>.
 163  */
 164 typedef struct { unsigned long pmd; } pmd_t;
 165 #define pmd_val(x)      ((x).pmd)
 166 #define __pmd(x)        ((pmd_t) { (x) } )
 167
 168
 169 extern pmd_t invalid_pmd_table[PTRS_PER_PMD];
 170 #endif
 171
 172 /*
 173  * Empty pgd/pmd entries point to the invalid_pte_table.
 174  */
 175 static inline int pmd_none(pmd_t pmd)
 176 {
 177         return pmd_val(pmd) == (unsigned long) invalid_pte_table;
 178 }
 179
 180 static inline int pmd_bad(pmd_t pmd)
 181 {
 182 #ifdef CONFIG_MIPS_HUGE_TLB_SUPPORT
 183         /* pmd_huge(pmd) but inline */
 184         if (unlikely(pmd_val(pmd) & _PAGE_HUGE))
 185                 return 0;
 186 #endif
 187
 188         if (unlikely(pmd_val(pmd) & ~PAGE_MASK))
 189                 return 1;
 190
 191         return 0;
 192 }
 193
 194 static inline int pmd_present(pmd_t pmd)
 195 {
 196         return pmd_val(pmd) != (unsigned long) invalid_pte_table;
 197 }
 198
 199 static inline void pmd_clear(pmd_t *pmdp)
 200 {
 201         pmd_val(*pmdp) = ((unsigned long) invalid_pte_table);
 202 }
 203 #ifndef __PAGETABLE_PMD_FOLDED
 204
 205 /*
 206  * Empty pud entries point to the invalid_pmd_table.
 207  */
 208 static inline int pud_none(pud_t pud)
 209 {
 210         return pud_val(pud) == (unsigned long) invalid_pmd_table;
 211 }
 212
 213 static inline int pud_bad(pud_t pud)
 214 {
 215         return pud_val(pud) & ~PAGE_MASK;
 216 }
 217
 218 static inline int pud_present(pud_t pud)
 219 {
 220         return pud_val(pud) != (unsigned long) invalid_pmd_table;
 221 }
 222
 223 static inline void pud_clear(pud_t *pudp)
 224 {
 225         pud_val(*pudp) = ((unsigned long) invalid_pmd_table);
 226 }
 227 #endif
 228
 229 #define pte_page(x)             pfn_to_page(pte_pfn(x))
 230
 231 #ifdef CONFIG_CPU_VR41XX
 232 #define pte_pfn(x)              ((unsigned long)((x).pte >> (PAGE_SHIFT + 2)))
 233 #define pfn_pte(pfn, prot)      __pte(((pfn) << (PAGE_SHIFT + 2)) | pgprot_val(prot))
 234 #else
 235 #define pte_pfn(x)              ((unsigned long)((x).pte >> _PFN_SHIFT))
 236 #define pfn_pte(pfn, prot)      __pte(((pfn) << _PFN_SHIFT) | pgprot_val(prot))
 237 #define pfn_pmd(pfn, prot)      __pmd(((pfn) << _PFN_SHIFT) | pgprot_val(prot))
 238 #endif
 239
 240 #define __pgd_offset(address)   pgd_index(address)
 241 #define __pud_offset(address)   (((address) >> PUD_SHIFT) & (PTRS_PER_PUD-1))
 242 #define __pmd_offset(address)   pmd_index(address)
 243
 244 /* to find an entry in a kernel page-table-directory */
 245 #define pgd_offset_k(address) pgd_offset(&init_mm, address)
 246
 247 #define pgd_index(address)      (((address) >> PGDIR_SHIFT) & (PTRS_PER_PGD-1))
 248 #define pmd_index(address)      (((address) >> PMD_SHIFT) & (PTRS_PER_PMD-1))
 249
 250 /* to find an entry in a page-table-directory */
 251 #define pgd_offset(mm, addr)    ((mm)->pgd + pgd_index(addr))
 252
 253 #ifndef __PAGETABLE_PMD_FOLDED
 254 static inline unsigned long pud_page_vaddr(pud_t pud)
 255 {
 256         return pud_val(pud);
 257 }
 258 #define pud_phys(pud)           virt_to_phys((void *)pud_val(pud))
 259 #define pud_page(pud)           (pfn_to_page(pud_phys(pud) >> PAGE_SHIFT))
 260
 261 /* Find an entry in the second-level page table.. */
 262 static inline pmd_t *pmd_offset(pud_t * pud, unsigned long address)
 263 {
 264         return (pmd_t *) pud_page_vaddr(*pud) + pmd_index(address);
 265 }
 266 #endif
 267
 268 /* Find an entry in the third-level page table.. */
 269 #define __pte_offset(address)                                           \
 270         (((address) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
 271 #define pte_offset(dir, address)                                        \
 272         ((pte_t *) pmd_page_vaddr(*(dir)) + __pte_offset(address))
 273 #define pte_offset_kernel(dir, address)                                 \
 274         ((pte_t *) pmd_page_vaddr(*(dir)) + __pte_offset(address))
 275 #define pte_offset_map(dir, address)                                    \
 276         ((pte_t *)page_address(pmd_page(*(dir))) + __pte_offset(address))
 277 #define pte_unmap(pte) ((void)(pte))
 278
 279 /*
 280  * Initialize a new pgd / pmd table with invalid pointers.
 281  */
 282 extern void pgd_init(unsigned long page);
 283 extern void pmd_init(unsigned long page, unsigned long pagetable);
 284
 285 /*
 286  * Non-present pages:  high 40 bits are offset, next 8 bits type,
 287  * low 16 bits zero.
 288  */
 289 static inline pte_t mk_swap_pte(unsigned long type, unsigned long offset)
 290 { pte_t pte; pte_val(pte) = (type << 16) | (offset << 24); return pte; }
 291
 292 #define __swp_type(x)           (((x).val >> 16) & 0xff)
 293 #define __swp_offset(x)         ((x).val >> 24)
 294 #define __swp_entry(type, offset) ((swp_entry_t) { pte_val(mk_swap_pte((type), (offset))) })
 295 #define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
 296 #define __swp_entry_to_pte(x)   ((pte_t) { (x).val })
 297
 298 #endif /* _ASM_PGTABLE_64_H */