arch/arm64/include/asm/pgtable.h

   1 /*
   2  * Copyright (C) 2012 ARM Ltd.
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License version 2 as
   6  * published by the Free Software Foundation.
   7  *
   8  * This program is distributed in the hope that it will be useful,
   9  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  10  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  11  * GNU General Public License for more details.
  12  *
  13  * You should have received a copy of the GNU General Public License
  14  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  15  */
  16 #ifndef __ASM_PGTABLE_H
  17 #define __ASM_PGTABLE_H
  18
  19 #include <asm/proc-fns.h>
  20
  21 #include <asm/memory.h>
  22 #include <asm/pgtable-hwdef.h>
  23
  24 /*
  25  * Software defined PTE bits definition.
  26  */
  27 #define PTE_VALID               (_AT(pteval_t, 1) << 0)
  28 #define PTE_DIRTY               (_AT(pteval_t, 1) << 55)
  29 #define PTE_SPECIAL             (_AT(pteval_t, 1) << 56)
  30 #define PTE_WRITE               (_AT(pteval_t, 1) << 57)
  31 #define PTE_PROT_NONE           (_AT(pteval_t, 1) << 58) /* only when !PTE_VALID */
  32
  33 /*
  34  * VMALLOC and SPARSEMEM_VMEMMAP ranges.
  35  *
  36  * VMEMAP_SIZE: allows the whole VA space to be covered by a struct page array
  37  *      (rounded up to PUD_SIZE).
  38  * VMALLOC_START: beginning of the kernel VA space
  39  * VMALLOC_END: extends to the available space below vmmemmap, PCI I/O space,
  40  *      fixed mappings and modules
  41  */
  42 #define VMEMMAP_SIZE            ALIGN((1UL << (VA_BITS - PAGE_SHIFT)) * sizeof(struct page), PUD_SIZE)
  43 #define VMALLOC_START           (UL(0xffffffffffffffff) << VA_BITS)
  44 #define VMALLOC_END             (PAGE_OFFSET - PUD_SIZE - VMEMMAP_SIZE - SZ_64K)
  45
  46 #define vmemmap                 ((struct page *)(VMALLOC_END + SZ_64K))
  47
  48 #define FIRST_USER_ADDRESS      0
  49
  50 #ifndef __ASSEMBLY__
  51 extern void __pte_error(const char *file, int line, unsigned long val);
  52 extern void __pmd_error(const char *file, int line, unsigned long val);
  53 extern void __pud_error(const char *file, int line, unsigned long val);
  54 extern void __pgd_error(const char *file, int line, unsigned long val);
  55
  56 #ifdef CONFIG_SMP
  57 #define PROT_DEFAULT            (PTE_TYPE_PAGE | PTE_AF | PTE_SHARED)
  58 #define PROT_SECT_DEFAULT       (PMD_TYPE_SECT | PMD_SECT_AF | PMD_SECT_S)
  59 #else
  60 #define PROT_DEFAULT            (PTE_TYPE_PAGE | PTE_AF)
  61 #define PROT_SECT_DEFAULT       (PMD_TYPE_SECT | PMD_SECT_AF)
  62 #endif
  63
  64 #define PROT_DEVICE_nGnRE       (PROT_DEFAULT | PTE_PXN | PTE_UXN | PTE_ATTRINDX(MT_DEVICE_nGnRE))
  65 #define PROT_NORMAL_NC          (PROT_DEFAULT | PTE_PXN | PTE_UXN | PTE_ATTRINDX(MT_NORMAL_NC))
  66 #define PROT_NORMAL             (PROT_DEFAULT | PTE_PXN | PTE_UXN | PTE_ATTRINDX(MT_NORMAL))
  67
  68 #define PROT_SECT_DEVICE_nGnRE  (PROT_SECT_DEFAULT | PMD_SECT_PXN | PMD_SECT_UXN | PMD_ATTRINDX(MT_DEVICE_nGnRE))
  69 #define PROT_SECT_NORMAL        (PROT_SECT_DEFAULT | PMD_SECT_PXN | PMD_SECT_UXN | PMD_ATTRINDX(MT_NORMAL))
  70 #define PROT_SECT_NORMAL_EXEC   (PROT_SECT_DEFAULT | PMD_SECT_UXN | PMD_ATTRINDX(MT_NORMAL))
  71
  72 #define _PAGE_DEFAULT           (PROT_DEFAULT | PTE_ATTRINDX(MT_NORMAL))
  73
  74 #define PAGE_KERNEL             __pgprot(_PAGE_DEFAULT | PTE_PXN | PTE_UXN | PTE_DIRTY | PTE_WRITE)
  75 #define PAGE_KERNEL_EXEC        __pgprot(_PAGE_DEFAULT | PTE_UXN | PTE_DIRTY | PTE_WRITE)
  76
  77 #define PAGE_HYP                __pgprot(_PAGE_DEFAULT | PTE_HYP)
  78 #define PAGE_HYP_DEVICE         __pgprot(PROT_DEVICE_nGnRE | PTE_HYP)
  79
  80 #define PAGE_S2                 __pgprot(PROT_DEFAULT | PTE_S2_MEMATTR(MT_S2_NORMAL) | PTE_S2_RDONLY)
  81 #define PAGE_S2_DEVICE          __pgprot(PROT_DEFAULT | PTE_S2_MEMATTR(MT_S2_DEVICE_nGnRE) | PTE_S2_RDONLY | PTE_UXN)
  82
  83 #define PAGE_NONE               __pgprot(((_PAGE_DEFAULT) & ~PTE_TYPE_MASK) | PTE_PROT_NONE | PTE_PXN | PTE_UXN)
  84 #define PAGE_SHARED             __pgprot(_PAGE_DEFAULT | PTE_USER | PTE_NG | PTE_PXN | PTE_UXN | PTE_WRITE)
  85 #define PAGE_SHARED_EXEC        __pgprot(_PAGE_DEFAULT | PTE_USER | PTE_NG | PTE_PXN | PTE_WRITE)
  86 #define PAGE_COPY               __pgprot(_PAGE_DEFAULT | PTE_USER | PTE_NG | PTE_PXN | PTE_UXN)
  87 #define PAGE_COPY_EXEC          __pgprot(_PAGE_DEFAULT | PTE_USER | PTE_NG | PTE_PXN)
  88 #define PAGE_READONLY           __pgprot(_PAGE_DEFAULT | PTE_USER | PTE_NG | PTE_PXN | PTE_UXN)
  89 #define PAGE_READONLY_EXEC      __pgprot(_PAGE_DEFAULT | PTE_USER | PTE_NG | PTE_PXN)
  90
  91 #define __P000  PAGE_NONE
  92 #define __P001  PAGE_READONLY
  93 #define __P010  PAGE_COPY
  94 #define __P011  PAGE_COPY
  95 #define __P100  PAGE_READONLY_EXEC
  96 #define __P101  PAGE_READONLY_EXEC
  97 #define __P110  PAGE_COPY_EXEC
  98 #define __P111  PAGE_COPY_EXEC
  99
 100 #define __S000  PAGE_NONE
 101 #define __S001  PAGE_READONLY
 102 #define __S010  PAGE_SHARED
 103 #define __S011  PAGE_SHARED
 104 #define __S100  PAGE_READONLY_EXEC
 105 #define __S101  PAGE_READONLY_EXEC
 106 #define __S110  PAGE_SHARED_EXEC
 107 #define __S111  PAGE_SHARED_EXEC
 108
 109 /*
 110  * ZERO_PAGE is a global shared page that is always zero: used
 111  * for zero-mapped memory areas etc..
 112  */
 113 extern struct page *empty_zero_page;
 114 #define ZERO_PAGE(vaddr)        (empty_zero_page)
 115
 116 #define pte_ERROR(pte)          __pte_error(__FILE__, __LINE__, pte_val(pte))
 117
 118 #define pte_pfn(pte)            ((pte_val(pte) & PHYS_MASK) >> PAGE_SHIFT)
 119
 120 #define pfn_pte(pfn,prot)       (__pte(((phys_addr_t)(pfn) << PAGE_SHIFT) | pgprot_val(prot)))
 121
 122 #define pte_none(pte)           (!pte_val(pte))
 123 #define pte_clear(mm,addr,ptep) set_pte(ptep, __pte(0))
 124 #define pte_page(pte)           (pfn_to_page(pte_pfn(pte)))
 125
 126 /* Find an entry in the third-level page table. */
 127 #define pte_index(addr)         (((addr) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
 128
 129 #define pte_offset_kernel(dir,addr)     (pmd_page_vaddr(*(dir)) + pte_index(addr))
 130
 131 #define pte_offset_map(dir,addr)        pte_offset_kernel((dir), (addr))
 132 #define pte_offset_map_nested(dir,addr) pte_offset_kernel((dir), (addr))
 133 #define pte_unmap(pte)                  do { } while (0)
 134 #define pte_unmap_nested(pte)           do { } while (0)
 135
 136 /*
 137  * The following only work if pte_present(). Undefined behaviour otherwise.
 138  */
 139 #define pte_present(pte)        (!!(pte_val(pte) & (PTE_VALID | PTE_PROT_NONE)))
 140 #define pte_dirty(pte)          (!!(pte_val(pte) & PTE_DIRTY))
 141 #define pte_young(pte)          (!!(pte_val(pte) & PTE_AF))
 142 #define pte_special(pte)        (!!(pte_val(pte) & PTE_SPECIAL))
 143 #define pte_write(pte)          (!!(pte_val(pte) & PTE_WRITE))
 144 #define pte_exec(pte)           (!(pte_val(pte) & PTE_UXN))
 145
 146 #define pte_valid_user(pte) \
 147         ((pte_val(pte) & (PTE_VALID | PTE_USER)) == (PTE_VALID | PTE_USER))
 148 #define pte_valid_not_user(pte) \
 149         ((pte_val(pte) & (PTE_VALID | PTE_USER)) == PTE_VALID)
 150
 151 static inline pte_t clear_pte_bit(pte_t pte, pgprot_t prot)
 152 {
 153         pte_val(pte) &= ~pgprot_val(prot);
 154         return pte;
 155 }
 156
 157 static inline pte_t set_pte_bit(pte_t pte, pgprot_t prot)
 158 {
 159         pte_val(pte) |= pgprot_val(prot);
 160         return pte;
 161 }
 162
 163 static inline pte_t pte_wrprotect(pte_t pte)
 164 {
 165         return clear_pte_bit(pte, __pgprot(PTE_WRITE));
 166 }
 167
 168 static inline pte_t pte_mkwrite(pte_t pte)
 169 {
 170         return set_pte_bit(pte, __pgprot(PTE_WRITE));
 171 }
 172
 173 static inline pte_t pte_mkclean(pte_t pte)
 174 {
 175         return clear_pte_bit(pte, __pgprot(PTE_DIRTY));
 176 }
 177
 178 static inline pte_t pte_mkdirty(pte_t pte)
 179 {
 180         return set_pte_bit(pte, __pgprot(PTE_DIRTY));
 181 }
 182
 183 static inline pte_t pte_mkold(pte_t pte)
 184 {
 185         return clear_pte_bit(pte, __pgprot(PTE_AF));
 186 }
 187
 188 static inline pte_t pte_mkyoung(pte_t pte)
 189 {
 190         return set_pte_bit(pte, __pgprot(PTE_AF));
 191 }
 192
 193 static inline pte_t pte_mkspecial(pte_t pte)
 194 {
 195         return set_pte_bit(pte, __pgprot(PTE_SPECIAL));
 196 }
 197
 198 static inline void set_pte(pte_t *ptep, pte_t pte)
 199 {
 200         *ptep = pte;
 201
 202         /*
 203          * Only if the new pte is valid and kernel, otherwise TLB maintenance
 204          * or update_mmu_cache() have the necessary barriers.
 205          */
 206         if (pte_valid_not_user(pte)) {
 207                 dsb(ishst);
 208                 isb();
 209         }
 210 }
 211
 212 extern void __sync_icache_dcache(pte_t pteval, unsigned long addr);
 213
 214 static inline void set_pte_at(struct mm_struct *mm, unsigned long addr,
 215                               pte_t *ptep, pte_t pte)
 216 {
 217         if (pte_valid_user(pte)) {
 218                 if (!pte_special(pte) && pte_exec(pte))
 219                         __sync_icache_dcache(pte, addr);
 220                 if (pte_dirty(pte) && pte_write(pte))
 221                         pte_val(pte) &= ~PTE_RDONLY;
 222                 else
 223                         pte_val(pte) |= PTE_RDONLY;
 224         }
 225
 226         set_pte(ptep, pte);
 227 }
 228
 229 /*
 230  * Huge pte definitions.
 231  */
 232 #define pte_huge(pte)           (!(pte_val(pte) & PTE_TABLE_BIT))
 233 #define pte_mkhuge(pte)         (__pte(pte_val(pte) & ~PTE_TABLE_BIT))
 234
 235 /*
 236  * Hugetlb definitions.
 237  */
 238 #define HUGE_MAX_HSTATE         2
 239 #define HPAGE_SHIFT             PMD_SHIFT
 240 #define HPAGE_SIZE              (_AC(1, UL) << HPAGE_SHIFT)
 241 #define HPAGE_MASK              (~(HPAGE_SIZE - 1))
 242 #define HUGETLB_PAGE_ORDER      (HPAGE_SHIFT - PAGE_SHIFT)
 243
 244 #define __HAVE_ARCH_PTE_SPECIAL
 245
 246 static inline pte_t pud_pte(pud_t pud)
 247 {
 248         return __pte(pud_val(pud));
 249 }
 250
 251 static inline pmd_t pud_pmd(pud_t pud)
 252 {
 253         return __pmd(pud_val(pud));
 254 }
 255
 256 static inline pte_t pmd_pte(pmd_t pmd)
 257 {
 258         return __pte(pmd_val(pmd));
 259 }
 260
 261 static inline pmd_t pte_pmd(pte_t pte)
 262 {
 263         return __pmd(pte_val(pte));
 264 }
 265
 266 /*
 267  * THP definitions.
 268  */
 269
 270 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 271 #define pmd_trans_huge(pmd)     (pmd_val(pmd) && !(pmd_val(pmd) & PMD_TABLE_BIT))
 272 #define pmd_trans_splitting(pmd)        pte_special(pmd_pte(pmd))
 273 #ifdef CONFIG_HAVE_RCU_TABLE_FREE
 274 #define __HAVE_ARCH_PMDP_SPLITTING_FLUSH
 275 struct vm_area_struct;
 276 void pmdp_splitting_flush(struct vm_area_struct *vma, unsigned long address,
 277                           pmd_t *pmdp);
 278 #endif /* CONFIG_HAVE_RCU_TABLE_FREE */
 279 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 280
 281 #define pmd_dirty(pmd)          pte_dirty(pmd_pte(pmd))
 282 #define pmd_young(pmd)          pte_young(pmd_pte(pmd))
 283 #define pmd_wrprotect(pmd)      pte_pmd(pte_wrprotect(pmd_pte(pmd)))
 284 #define pmd_mksplitting(pmd)    pte_pmd(pte_mkspecial(pmd_pte(pmd)))
 285 #define pmd_mkold(pmd)          pte_pmd(pte_mkold(pmd_pte(pmd)))
 286 #define pmd_mkwrite(pmd)        pte_pmd(pte_mkwrite(pmd_pte(pmd)))
 287 #define pmd_mkdirty(pmd)        pte_pmd(pte_mkdirty(pmd_pte(pmd)))
 288 #define pmd_mkyoung(pmd)        pte_pmd(pte_mkyoung(pmd_pte(pmd)))
 289 #define pmd_mknotpresent(pmd)   (__pmd(pmd_val(pmd) & ~PMD_TYPE_MASK))
 290
 291 #define __HAVE_ARCH_PMD_WRITE
 292 #define pmd_write(pmd)          pte_write(pmd_pte(pmd))
 293
 294 #define pmd_mkhuge(pmd)         (__pmd(pmd_val(pmd) & ~PMD_TABLE_BIT))
 295
 296 #define pmd_pfn(pmd)            (((pmd_val(pmd) & PMD_MASK) & PHYS_MASK) >> PAGE_SHIFT)
 297 #define pfn_pmd(pfn,prot)       (__pmd(((phys_addr_t)(pfn) << PAGE_SHIFT) | pgprot_val(prot)))
 298 #define mk_pmd(page,prot)       pfn_pmd(page_to_pfn(page),prot)
 299
 300 #define pud_write(pud)          pte_write(pud_pte(pud))
 301 #define pud_pfn(pud)            (((pud_val(pud) & PUD_MASK) & PHYS_MASK) >> PAGE_SHIFT)
 302
 303 #define set_pmd_at(mm, addr, pmdp, pmd) set_pte_at(mm, addr, (pte_t *)pmdp, pmd_pte(pmd))
 304
 305 static inline int has_transparent_hugepage(void)
 306 {
 307         return 1;
 308 }
 309
 310 #define __pgprot_modify(prot,mask,bits) \
 311         __pgprot((pgprot_val(prot) & ~(mask)) | (bits))
 312
 313 /*
 314  * Mark the prot value as uncacheable and unbufferable.
 315  */
 316 #define pgprot_noncached(prot) \
 317         __pgprot_modify(prot, PTE_ATTRINDX_MASK, PTE_ATTRINDX(MT_DEVICE_nGnRnE) | PTE_PXN | PTE_UXN)
 318 #define pgprot_writecombine(prot) \
 319         __pgprot_modify(prot, PTE_ATTRINDX_MASK, PTE_ATTRINDX(MT_NORMAL_NC) | PTE_PXN | PTE_UXN)
 320 #define pgprot_device(prot) \
 321         __pgprot_modify(prot, PTE_ATTRINDX_MASK, PTE_ATTRINDX(MT_DEVICE_nGnRE) | PTE_PXN | PTE_UXN)
 322 #define __HAVE_PHYS_MEM_ACCESS_PROT
 323 struct file;
 324 extern pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
 325                                      unsigned long size, pgprot_t vma_prot);
 326
 327 #define pmd_none(pmd)           (!pmd_val(pmd))
 328 #define pmd_present(pmd)        (pmd_val(pmd))
 329
 330 #define pmd_bad(pmd)            (!(pmd_val(pmd) & 2))
 331
 332 #define pmd_table(pmd)          ((pmd_val(pmd) & PMD_TYPE_MASK) == \
 333                                  PMD_TYPE_TABLE)
 334 #define pmd_sect(pmd)           ((pmd_val(pmd) & PMD_TYPE_MASK) == \
 335                                  PMD_TYPE_SECT)
 336
 337 #ifdef CONFIG_ARM64_64K_PAGES
 338 #define pud_sect(pud)           (0)
 339 #else
 340 #define pud_sect(pud)           ((pud_val(pud) & PUD_TYPE_MASK) == \
 341                                  PUD_TYPE_SECT)
 342 #endif
 343
 344 static inline void set_pmd(pmd_t *pmdp, pmd_t pmd)
 345 {
 346         *pmdp = pmd;
 347         dsb(ishst);
 348         isb();
 349 }
 350
 351 static inline void pmd_clear(pmd_t *pmdp)
 352 {
 353         set_pmd(pmdp, __pmd(0));
 354 }
 355
 356 static inline pte_t *pmd_page_vaddr(pmd_t pmd)
 357 {
 358         return __va(pmd_val(pmd) & PHYS_MASK & (s32)PAGE_MASK);
 359 }
 360
 361 #define pmd_page(pmd)           pfn_to_page(__phys_to_pfn(pmd_val(pmd) & PHYS_MASK))
 362
 363 /*
 364  * Conversion functions: convert a page and protection to a page entry,
 365  * and a page entry and page directory to the page they refer to.
 366  */
 367 #define mk_pte(page,prot)       pfn_pte(page_to_pfn(page),prot)
 368
 369 #if CONFIG_ARM64_PGTABLE_LEVELS > 2
 370
 371 #define pmd_ERROR(pmd)          __pmd_error(__FILE__, __LINE__, pmd_val(pmd))
 372
 373 #define pud_none(pud)           (!pud_val(pud))
 374 #define pud_bad(pud)            (!(pud_val(pud) & 2))
 375 #define pud_present(pud)        (pud_val(pud))
 376
 377 static inline void set_pud(pud_t *pudp, pud_t pud)
 378 {
 379         *pudp = pud;
 380         dsb(ishst);
 381         isb();
 382 }
 383
 384 static inline void pud_clear(pud_t *pudp)
 385 {
 386         set_pud(pudp, __pud(0));
 387 }
 388
 389 static inline pmd_t *pud_page_vaddr(pud_t pud)
 390 {
 391         return __va(pud_val(pud) & PHYS_MASK & (s32)PAGE_MASK);
 392 }
 393
 394 /* Find an entry in the second-level page table. */
 395 #define pmd_index(addr)         (((addr) >> PMD_SHIFT) & (PTRS_PER_PMD - 1))
 396
 397 static inline pmd_t *pmd_offset(pud_t *pud, unsigned long addr)
 398 {
 399         return (pmd_t *)pud_page_vaddr(*pud) + pmd_index(addr);
 400 }
 401
 402 #define pud_page(pud)           pfn_to_page(__phys_to_pfn(pud_val(pud) & PHYS_MASK))
 403
 404 #endif  /* CONFIG_ARM64_PGTABLE_LEVELS > 2 */
 405
 406 #if CONFIG_ARM64_PGTABLE_LEVELS > 3
 407
 408 #define pud_ERROR(pud)          __pud_error(__FILE__, __LINE__, pud_val(pud))
 409
 410 #define pgd_none(pgd)           (!pgd_val(pgd))
 411 #define pgd_bad(pgd)            (!(pgd_val(pgd) & 2))
 412 #define pgd_present(pgd)        (pgd_val(pgd))
 413
 414 static inline void set_pgd(pgd_t *pgdp, pgd_t pgd)
 415 {
 416         *pgdp = pgd;
 417         dsb(ishst);
 418 }
 419
 420 static inline void pgd_clear(pgd_t *pgdp)
 421 {
 422         set_pgd(pgdp, __pgd(0));
 423 }
 424
 425 static inline pud_t *pgd_page_vaddr(pgd_t pgd)
 426 {
 427         return __va(pgd_val(pgd) & PHYS_MASK & (s32)PAGE_MASK);
 428 }
 429
 430 /* Find an entry in the frst-level page table. */
 431 #define pud_index(addr)         (((addr) >> PUD_SHIFT) & (PTRS_PER_PUD - 1))
 432
 433 static inline pud_t *pud_offset(pgd_t *pgd, unsigned long addr)
 434 {
 435         return (pud_t *)pgd_page_vaddr(*pgd) + pud_index(addr);
 436 }
 437
 438 #define pgd_page(pgd)           pfn_to_page(__phys_to_pfn(pgd_val(pgd) & PHYS_MASK))
 439
 440 #endif  /* CONFIG_ARM64_PGTABLE_LEVELS > 3 */
 441
 442 #define pgd_ERROR(pgd)          __pgd_error(__FILE__, __LINE__, pgd_val(pgd))
 443
 444 /* to find an entry in a page-table-directory */
 445 #define pgd_index(addr)         (((addr) >> PGDIR_SHIFT) & (PTRS_PER_PGD - 1))
 446
 447 #define pgd_offset(mm, addr)    ((mm)->pgd+pgd_index(addr))
 448
 449 /* to find an entry in a kernel page-table-directory */
 450 #define pgd_offset_k(addr)      pgd_offset(&init_mm, addr)
 451
 452 static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
 453 {
 454         const pteval_t mask = PTE_USER | PTE_PXN | PTE_UXN | PTE_RDONLY |
 455                               PTE_PROT_NONE | PTE_VALID | PTE_WRITE;
 456         pte_val(pte) = (pte_val(pte) & ~mask) | (pgprot_val(newprot) & mask);
 457         return pte;
 458 }
 459
 460 static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot)
 461 {
 462         return pte_pmd(pte_modify(pmd_pte(pmd), newprot));
 463 }
 464
 465 extern pgd_t swapper_pg_dir[PTRS_PER_PGD];
 466 extern pgd_t idmap_pg_dir[PTRS_PER_PGD];
 467
 468 /*
 469  * Encode and decode a swap entry:
 470  *      bits 0-1:       present (must be zero)
 471  *      bits 2-7:       swap type
 472  *      bits 8-57:      swap offset
 473  */
 474 #define __SWP_TYPE_SHIFT        2
 475 #define __SWP_TYPE_BITS         6
 476 #define __SWP_OFFSET_BITS       50
 477 #define __SWP_TYPE_MASK         ((1 << __SWP_TYPE_BITS) - 1)
 478 #define __SWP_OFFSET_SHIFT      (__SWP_TYPE_BITS + __SWP_TYPE_SHIFT)
 479 #define __SWP_OFFSET_MASK       ((1UL << __SWP_OFFSET_BITS) - 1)
 480
 481 #define __swp_type(x)           (((x).val >> __SWP_TYPE_SHIFT) & __SWP_TYPE_MASK)
 482 #define __swp_offset(x)         (((x).val >> __SWP_OFFSET_SHIFT) & __SWP_OFFSET_MASK)
 483 #define __swp_entry(type,offset) ((swp_entry_t) { ((type) << __SWP_TYPE_SHIFT) | ((offset) << __SWP_OFFSET_SHIFT) })
 484
 485 #define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
 486 #define __swp_entry_to_pte(swp) ((pte_t) { (swp).val })
 487
 488 /*
 489  * Ensure that there are not more swap files than can be encoded in the kernel
 490  * PTEs.
 491  */
 492 #define MAX_SWAPFILES_CHECK() BUILD_BUG_ON(MAX_SWAPFILES_SHIFT > __SWP_TYPE_BITS)
 493
 494 extern int kern_addr_valid(unsigned long addr);
 495
 496 #include <asm-generic/pgtable.h>
 497
 498 #define pgtable_cache_init() do { } while (0)
 499
 500 #endif /* !__ASSEMBLY__ */
 501
 502 #endif /* __ASM_PGTABLE_H */