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_FILE                (_AT(pteval_t, 1) << 2) /* only when !pte_present() */
  29 #define PTE_DIRTY               (_AT(pteval_t, 1) << 55)
  30 #define PTE_SPECIAL             (_AT(pteval_t, 1) << 56)
  31 #define PTE_WRITE               (_AT(pteval_t, 1) << 57)
  32 #define PTE_PROT_NONE           (_AT(pteval_t, 1) << 58) /* only when !PTE_VALID */
  33
  34 /*
  35  * VMALLOC and SPARSEMEM_VMEMMAP ranges.
  36  *
  37  * VMEMAP_SIZE: allows the whole VA space to be covered by a struct page array
  38  *      (rounded up to PUD_SIZE).
  39  * VMALLOC_START: beginning of the kernel VA space
  40  * VMALLOC_END: extends to the available space below vmmemmap, PCI I/O space,
  41  *      fixed mappings and modules
  42  */
  43 #define VMEMMAP_SIZE            ALIGN((1UL << (VA_BITS - PAGE_SHIFT)) * sizeof(struct page), PUD_SIZE)
  44 #define VMALLOC_START           (UL(0xffffffffffffffff) << VA_BITS)
  45 #define VMALLOC_END             (PAGE_OFFSET - PUD_SIZE - VMEMMAP_SIZE - SZ_64K)
  46
  47 #define vmemmap                 ((struct page *)(VMALLOC_END + SZ_64K))
  48
  49 #define FIRST_USER_ADDRESS      0
  50
  51 #ifndef __ASSEMBLY__
  52 extern void __pte_error(const char *file, int line, unsigned long val);
  53 extern void __pmd_error(const char *file, int line, unsigned long val);
  54 extern void __pud_error(const char *file, int line, unsigned long val);
  55 extern void __pgd_error(const char *file, int line, unsigned long val);
  56
  57 #ifdef CONFIG_SMP
  58 #define PROT_DEFAULT            (PTE_TYPE_PAGE | PTE_AF | PTE_SHARED)
  59 #define PROT_SECT_DEFAULT       (PMD_TYPE_SECT | PMD_SECT_AF | PMD_SECT_S)
  60 #else
  61 #define PROT_DEFAULT            (PTE_TYPE_PAGE | PTE_AF)
  62 #define PROT_SECT_DEFAULT       (PMD_TYPE_SECT | PMD_SECT_AF)
  63 #endif
  64
  65 #define PROT_DEVICE_nGnRE       (PROT_DEFAULT | PTE_PXN | PTE_UXN | PTE_ATTRINDX(MT_DEVICE_nGnRE))
  66 #define PROT_NORMAL_NC          (PROT_DEFAULT | PTE_PXN | PTE_UXN | PTE_ATTRINDX(MT_NORMAL_NC))
  67 #define PROT_NORMAL             (PROT_DEFAULT | PTE_PXN | PTE_UXN | PTE_ATTRINDX(MT_NORMAL))
  68
  69 #define PROT_SECT_DEVICE_nGnRE  (PROT_SECT_DEFAULT | PMD_SECT_PXN | PMD_SECT_UXN | PMD_ATTRINDX(MT_DEVICE_nGnRE))
  70 #define PROT_SECT_NORMAL        (PROT_SECT_DEFAULT | PMD_SECT_PXN | PMD_SECT_UXN | PMD_ATTRINDX(MT_NORMAL))
  71 #define PROT_SECT_NORMAL_EXEC   (PROT_SECT_DEFAULT | PMD_SECT_UXN | PMD_ATTRINDX(MT_NORMAL))
  72
  73 #define _PAGE_DEFAULT           (PROT_DEFAULT | PTE_ATTRINDX(MT_NORMAL))
  74
  75 #define PAGE_KERNEL             __pgprot(_PAGE_DEFAULT | PTE_PXN | PTE_UXN | PTE_DIRTY | PTE_WRITE)
  76 #define PAGE_KERNEL_EXEC        __pgprot(_PAGE_DEFAULT | PTE_UXN | PTE_DIRTY | PTE_WRITE)
  77
  78 #define PAGE_HYP                __pgprot(_PAGE_DEFAULT | PTE_HYP)
  79 #define PAGE_HYP_DEVICE         __pgprot(PROT_DEVICE_nGnRE | PTE_HYP)
  80
  81 #define PAGE_S2                 __pgprot(PROT_DEFAULT | PTE_S2_MEMATTR(MT_S2_NORMAL) | PTE_S2_RDONLY)
  82 #define PAGE_S2_DEVICE          __pgprot(PROT_DEFAULT | PTE_S2_MEMATTR(MT_S2_DEVICE_nGnRE) | PTE_S2_RDONLY | PTE_UXN)
  83
  84 #define PAGE_NONE               __pgprot(((_PAGE_DEFAULT) & ~PTE_TYPE_MASK) | PTE_PROT_NONE | PTE_PXN | PTE_UXN)
  85 #define PAGE_SHARED             __pgprot(_PAGE_DEFAULT | PTE_USER | PTE_NG | PTE_PXN | PTE_UXN | PTE_WRITE)
  86 #define PAGE_SHARED_EXEC        __pgprot(_PAGE_DEFAULT | PTE_USER | PTE_NG | PTE_PXN | PTE_WRITE)
  87 #define PAGE_COPY               __pgprot(_PAGE_DEFAULT | PTE_USER | PTE_NG | PTE_PXN | PTE_UXN)
  88 #define PAGE_COPY_EXEC          __pgprot(_PAGE_DEFAULT | PTE_USER | PTE_NG | PTE_PXN)
  89 #define PAGE_READONLY           __pgprot(_PAGE_DEFAULT | PTE_USER | PTE_NG | PTE_PXN | PTE_UXN)
  90 #define PAGE_READONLY_EXEC      __pgprot(_PAGE_DEFAULT | PTE_USER | PTE_NG | PTE_PXN)
  91
  92 #define __P000  PAGE_NONE
  93 #define __P001  PAGE_READONLY
  94 #define __P010  PAGE_COPY
  95 #define __P011  PAGE_COPY
  96 #define __P100  PAGE_READONLY_EXEC
  97 #define __P101  PAGE_READONLY_EXEC
  98 #define __P110  PAGE_COPY_EXEC
  99 #define __P111  PAGE_COPY_EXEC
 100
 101 #define __S000  PAGE_NONE
 102 #define __S001  PAGE_READONLY
 103 #define __S010  PAGE_SHARED
 104 #define __S011  PAGE_SHARED
 105 #define __S100  PAGE_READONLY_EXEC
 106 #define __S101  PAGE_READONLY_EXEC
 107 #define __S110  PAGE_SHARED_EXEC
 108 #define __S111  PAGE_SHARED_EXEC
 109
 110 /*
 111  * ZERO_PAGE is a global shared page that is always zero: used
 112  * for zero-mapped memory areas etc..
 113  */
 114 extern struct page *empty_zero_page;
 115 #define ZERO_PAGE(vaddr)        (empty_zero_page)
 116
 117 #define pte_ERROR(pte)          __pte_error(__FILE__, __LINE__, pte_val(pte))
 118
 119 #define pte_pfn(pte)            ((pte_val(pte) & PHYS_MASK) >> PAGE_SHIFT)
 120
 121 #define pfn_pte(pfn,prot)       (__pte(((phys_addr_t)(pfn) << PAGE_SHIFT) | pgprot_val(prot)))
 122
 123 #define pte_none(pte)           (!pte_val(pte))
 124 #define pte_clear(mm,addr,ptep) set_pte(ptep, __pte(0))
 125 #define pte_page(pte)           (pfn_to_page(pte_pfn(pte)))
 126
 127 /* Find an entry in the third-level page table. */
 128 #define pte_index(addr)         (((addr) >> PAGE_SHIFT) & (PTRS_PER_PTE - 1))
 129
 130 #define pte_offset_kernel(dir,addr)     (pmd_page_vaddr(*(dir)) + pte_index(addr))
 131
 132 #define pte_offset_map(dir,addr)        pte_offset_kernel((dir), (addr))
 133 #define pte_offset_map_nested(dir,addr) pte_offset_kernel((dir), (addr))
 134 #define pte_unmap(pte)                  do { } while (0)
 135 #define pte_unmap_nested(pte)           do { } while (0)
 136
 137 /*
 138  * The following only work if pte_present(). Undefined behaviour otherwise.
 139  */
 140 #define pte_present(pte)        (!!(pte_val(pte) & (PTE_VALID | PTE_PROT_NONE)))
 141 #define pte_dirty(pte)          (!!(pte_val(pte) & PTE_DIRTY))
 142 #define pte_young(pte)          (!!(pte_val(pte) & PTE_AF))
 143 #define pte_special(pte)        (!!(pte_val(pte) & PTE_SPECIAL))
 144 #define pte_write(pte)          (!!(pte_val(pte) & PTE_WRITE))
 145 #define pte_exec(pte)           (!(pte_val(pte) & PTE_UXN))
 146
 147 #define pte_valid_user(pte) \
 148         ((pte_val(pte) & (PTE_VALID | PTE_USER)) == (PTE_VALID | PTE_USER))
 149 #define pte_valid_not_user(pte) \
 150         ((pte_val(pte) & (PTE_VALID | PTE_USER)) == PTE_VALID)
 151
 152 static inline pte_t clear_pte_bit(pte_t pte, pgprot_t prot)
 153 {
 154         pte_val(pte) &= ~pgprot_val(prot);
 155         return pte;
 156 }
 157
 158 static inline pte_t set_pte_bit(pte_t pte, pgprot_t prot)
 159 {
 160         pte_val(pte) |= pgprot_val(prot);
 161         return pte;
 162 }
 163
 164 static inline pte_t pte_wrprotect(pte_t pte)
 165 {
 166         return clear_pte_bit(pte, __pgprot(PTE_WRITE));
 167 }
 168
 169 static inline pte_t pte_mkwrite(pte_t pte)
 170 {
 171         return set_pte_bit(pte, __pgprot(PTE_WRITE));
 172 }
 173
 174 static inline pte_t pte_mkclean(pte_t pte)
 175 {
 176         return clear_pte_bit(pte, __pgprot(PTE_DIRTY));
 177 }
 178
 179 static inline pte_t pte_mkdirty(pte_t pte)
 180 {
 181         return set_pte_bit(pte, __pgprot(PTE_DIRTY));
 182 }
 183
 184 static inline pte_t pte_mkold(pte_t pte)
 185 {
 186         return clear_pte_bit(pte, __pgprot(PTE_AF));
 187 }
 188
 189 static inline pte_t pte_mkyoung(pte_t pte)
 190 {
 191         return set_pte_bit(pte, __pgprot(PTE_AF));
 192 }
 193
 194 static inline pte_t pte_mkspecial(pte_t pte)
 195 {
 196         return set_pte_bit(pte, __pgprot(PTE_SPECIAL));
 197 }
 198
 199 static inline void set_pte(pte_t *ptep, pte_t pte)
 200 {
 201         *ptep = pte;
 202
 203         /*
 204          * Only if the new pte is valid and kernel, otherwise TLB maintenance
 205          * or update_mmu_cache() have the necessary barriers.
 206          */
 207         if (pte_valid_not_user(pte)) {
 208                 dsb(ishst);
 209                 isb();
 210         }
 211 }
 212
 213 extern void __sync_icache_dcache(pte_t pteval, unsigned long addr);
 214
 215 static inline void set_pte_at(struct mm_struct *mm, unsigned long addr,
 216                               pte_t *ptep, pte_t pte)
 217 {
 218         if (pte_valid_user(pte)) {
 219                 if (!pte_special(pte) && pte_exec(pte))
 220                         __sync_icache_dcache(pte, addr);
 221                 if (pte_dirty(pte) && pte_write(pte))
 222                         pte_val(pte) &= ~PTE_RDONLY;
 223                 else
 224                         pte_val(pte) |= PTE_RDONLY;
 225         }
 226
 227         set_pte(ptep, pte);
 228 }
 229
 230 /*
 231  * Huge pte definitions.
 232  */
 233 #define pte_huge(pte)           (!(pte_val(pte) & PTE_TABLE_BIT))
 234 #define pte_mkhuge(pte)         (__pte(pte_val(pte) & ~PTE_TABLE_BIT))
 235
 236 /*
 237  * Hugetlb definitions.
 238  */
 239 #define HUGE_MAX_HSTATE         2
 240 #define HPAGE_SHIFT             PMD_SHIFT
 241 #define HPAGE_SIZE              (_AC(1, UL) << HPAGE_SHIFT)
 242 #define HPAGE_MASK              (~(HPAGE_SIZE - 1))
 243 #define HUGETLB_PAGE_ORDER      (HPAGE_SHIFT - PAGE_SHIFT)
 244
 245 #define __HAVE_ARCH_PTE_SPECIAL
 246
 247 static inline pte_t pud_pte(pud_t pud)
 248 {
 249         return __pte(pud_val(pud));
 250 }
 251
 252 static inline pmd_t pud_pmd(pud_t pud)
 253 {
 254         return __pmd(pud_val(pud));
 255 }
 256
 257 static inline pte_t pmd_pte(pmd_t pmd)
 258 {
 259         return __pte(pmd_val(pmd));
 260 }
 261
 262 static inline pmd_t pte_pmd(pte_t pte)
 263 {
 264         return __pmd(pte_val(pte));
 265 }
 266
 267 /*
 268  * THP definitions.
 269  */
 270
 271 #ifdef CONFIG_TRANSPARENT_HUGEPAGE
 272 #define pmd_trans_huge(pmd)     (pmd_val(pmd) && !(pmd_val(pmd) & PMD_TABLE_BIT))
 273 #define pmd_trans_splitting(pmd)        pte_special(pmd_pte(pmd))
 274 #ifdef CONFIG_HAVE_RCU_TABLE_FREE
 275 #define __HAVE_ARCH_PMDP_SPLITTING_FLUSH
 276 struct vm_area_struct;
 277 void pmdp_splitting_flush(struct vm_area_struct *vma, unsigned long address,
 278                           pmd_t *pmdp);
 279 #endif /* CONFIG_HAVE_RCU_TABLE_FREE */
 280 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */
 281
 282 #define pmd_dirty(pmd)          pte_dirty(pmd_pte(pmd))
 283 #define pmd_young(pmd)          pte_young(pmd_pte(pmd))
 284 #define pmd_wrprotect(pmd)      pte_pmd(pte_wrprotect(pmd_pte(pmd)))
 285 #define pmd_mksplitting(pmd)    pte_pmd(pte_mkspecial(pmd_pte(pmd)))
 286 #define pmd_mkold(pmd)          pte_pmd(pte_mkold(pmd_pte(pmd)))
 287 #define pmd_mkwrite(pmd)        pte_pmd(pte_mkwrite(pmd_pte(pmd)))
 288 #define pmd_mkdirty(pmd)        pte_pmd(pte_mkdirty(pmd_pte(pmd)))
 289 #define pmd_mkyoung(pmd)        pte_pmd(pte_mkyoung(pmd_pte(pmd)))
 290 #define pmd_mknotpresent(pmd)   (__pmd(pmd_val(pmd) & ~PMD_TYPE_MASK))
 291
 292 #define __HAVE_ARCH_PMD_WRITE
 293 #define pmd_write(pmd)          pte_write(pmd_pte(pmd))
 294
 295 #define pmd_mkhuge(pmd)         (__pmd(pmd_val(pmd) & ~PMD_TABLE_BIT))
 296
 297 #define pmd_pfn(pmd)            (((pmd_val(pmd) & PMD_MASK) & PHYS_MASK) >> PAGE_SHIFT)
 298 #define pfn_pmd(pfn,prot)       (__pmd(((phys_addr_t)(pfn) << PAGE_SHIFT) | pgprot_val(prot)))
 299 #define mk_pmd(page,prot)       pfn_pmd(page_to_pfn(page),prot)
 300
 301 #define pud_write(pud)          pte_write(pud_pte(pud))
 302 #define pud_pfn(pud)            (((pud_val(pud) & PUD_MASK) & PHYS_MASK) >> PAGE_SHIFT)
 303
 304 #define set_pmd_at(mm, addr, pmdp, pmd) set_pte_at(mm, addr, (pte_t *)pmdp, pmd_pte(pmd))
 305
 306 static inline int has_transparent_hugepage(void)
 307 {
 308         return 1;
 309 }
 310
 311 #define __pgprot_modify(prot,mask,bits) \
 312         __pgprot((pgprot_val(prot) & ~(mask)) | (bits))
 313
 314 /*
 315  * Mark the prot value as uncacheable and unbufferable.
 316  */
 317 #define pgprot_noncached(prot) \
 318         __pgprot_modify(prot, PTE_ATTRINDX_MASK, PTE_ATTRINDX(MT_DEVICE_nGnRnE) | PTE_PXN | PTE_UXN)
 319 #define pgprot_writecombine(prot) \
 320         __pgprot_modify(prot, PTE_ATTRINDX_MASK, PTE_ATTRINDX(MT_NORMAL_NC) | PTE_PXN | PTE_UXN)
 321 #define pgprot_device(prot) \
 322         __pgprot_modify(prot, PTE_ATTRINDX_MASK, PTE_ATTRINDX(MT_DEVICE_nGnRE) | PTE_PXN | PTE_UXN)
 323 #define __HAVE_PHYS_MEM_ACCESS_PROT
 324 struct file;
 325 extern pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn,
 326                                      unsigned long size, pgprot_t vma_prot);
 327
 328 #define pmd_none(pmd)           (!pmd_val(pmd))
 329 #define pmd_present(pmd)        (pmd_val(pmd))
 330
 331 #define pmd_bad(pmd)            (!(pmd_val(pmd) & 2))
 332
 333 #define pmd_table(pmd)          ((pmd_val(pmd) & PMD_TYPE_MASK) == \
 334                                  PMD_TYPE_TABLE)
 335 #define pmd_sect(pmd)           ((pmd_val(pmd) & PMD_TYPE_MASK) == \
 336                                  PMD_TYPE_SECT)
 337
 338 #ifdef CONFIG_ARM64_64K_PAGES
 339 #define pud_sect(pud)           (0)
 340 #else
 341 #define pud_sect(pud)           ((pud_val(pud) & PUD_TYPE_MASK) == \
 342                                  PUD_TYPE_SECT)
 343 #endif
 344
 345 static inline void set_pmd(pmd_t *pmdp, pmd_t pmd)
 346 {
 347         *pmdp = pmd;
 348         dsb(ishst);
 349         isb();
 350 }
 351
 352 static inline void pmd_clear(pmd_t *pmdp)
 353 {
 354         set_pmd(pmdp, __pmd(0));
 355 }
 356
 357 static inline pte_t *pmd_page_vaddr(pmd_t pmd)
 358 {
 359         return __va(pmd_val(pmd) & PHYS_MASK & (s32)PAGE_MASK);
 360 }
 361
 362 #define pmd_page(pmd)           pfn_to_page(__phys_to_pfn(pmd_val(pmd) & PHYS_MASK))
 363
 364 /*
 365  * Conversion functions: convert a page and protection to a page entry,
 366  * and a page entry and page directory to the page they refer to.
 367  */
 368 #define mk_pte(page,prot)       pfn_pte(page_to_pfn(page),prot)
 369
 370 #if CONFIG_ARM64_PGTABLE_LEVELS > 2
 371
 372 #define pmd_ERROR(pmd)          __pmd_error(__FILE__, __LINE__, pmd_val(pmd))
 373
 374 #define pud_none(pud)           (!pud_val(pud))
 375 #define pud_bad(pud)            (!(pud_val(pud) & 2))
 376 #define pud_present(pud)        (pud_val(pud))
 377
 378 static inline void set_pud(pud_t *pudp, pud_t pud)
 379 {
 380         *pudp = pud;
 381         dsb(ishst);
 382         isb();
 383 }
 384
 385 static inline void pud_clear(pud_t *pudp)
 386 {
 387         set_pud(pudp, __pud(0));
 388 }
 389
 390 static inline pmd_t *pud_page_vaddr(pud_t pud)
 391 {
 392         return __va(pud_val(pud) & PHYS_MASK & (s32)PAGE_MASK);
 393 }
 394
 395 /* Find an entry in the second-level page table. */
 396 #define pmd_index(addr)         (((addr) >> PMD_SHIFT) & (PTRS_PER_PMD - 1))
 397
 398 static inline pmd_t *pmd_offset(pud_t *pud, unsigned long addr)
 399 {
 400         return (pmd_t *)pud_page_vaddr(*pud) + pmd_index(addr);
 401 }
 402
 403 #define pud_page(pud)           pfn_to_page(__phys_to_pfn(pud_val(pud) & PHYS_MASK))
 404
 405 #endif  /* CONFIG_ARM64_PGTABLE_LEVELS > 2 */
 406
 407 #if CONFIG_ARM64_PGTABLE_LEVELS > 3
 408
 409 #define pud_ERROR(pud)          __pud_error(__FILE__, __LINE__, pud_val(pud))
 410
 411 #define pgd_none(pgd)           (!pgd_val(pgd))
 412 #define pgd_bad(pgd)            (!(pgd_val(pgd) & 2))
 413 #define pgd_present(pgd)        (pgd_val(pgd))
 414
 415 static inline void set_pgd(pgd_t *pgdp, pgd_t pgd)
 416 {
 417         *pgdp = pgd;
 418         dsb(ishst);
 419 }
 420
 421 static inline void pgd_clear(pgd_t *pgdp)
 422 {
 423         set_pgd(pgdp, __pgd(0));
 424 }
 425
 426 static inline pud_t *pgd_page_vaddr(pgd_t pgd)
 427 {
 428         return __va(pgd_val(pgd) & PHYS_MASK & (s32)PAGE_MASK);
 429 }
 430
 431 /* Find an entry in the frst-level page table. */
 432 #define pud_index(addr)         (((addr) >> PUD_SHIFT) & (PTRS_PER_PUD - 1))
 433
 434 static inline pud_t *pud_offset(pgd_t *pgd, unsigned long addr)
 435 {
 436         return (pud_t *)pgd_page_vaddr(*pgd) + pud_index(addr);
 437 }
 438
 439 #define pgd_page(pgd)           pfn_to_page(__phys_to_pfn(pgd_val(pgd) & PHYS_MASK))
 440
 441 #endif  /* CONFIG_ARM64_PGTABLE_LEVELS > 3 */
 442
 443 #define pgd_ERROR(pgd)          __pgd_error(__FILE__, __LINE__, pgd_val(pgd))
 444
 445 /* to find an entry in a page-table-directory */
 446 #define pgd_index(addr)         (((addr) >> PGDIR_SHIFT) & (PTRS_PER_PGD - 1))
 447
 448 #define pgd_offset(mm, addr)    ((mm)->pgd+pgd_index(addr))
 449
 450 /* to find an entry in a kernel page-table-directory */
 451 #define pgd_offset_k(addr)      pgd_offset(&init_mm, addr)
 452
 453 static inline pte_t pte_modify(pte_t pte, pgprot_t newprot)
 454 {
 455         const pteval_t mask = PTE_USER | PTE_PXN | PTE_UXN | PTE_RDONLY |
 456                               PTE_PROT_NONE | PTE_VALID | PTE_WRITE;
 457         pte_val(pte) = (pte_val(pte) & ~mask) | (pgprot_val(newprot) & mask);
 458         return pte;
 459 }
 460
 461 static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot)
 462 {
 463         return pte_pmd(pte_modify(pmd_pte(pmd), newprot));
 464 }
 465
 466 extern pgd_t swapper_pg_dir[PTRS_PER_PGD];
 467 extern pgd_t idmap_pg_dir[PTRS_PER_PGD];
 468
 469 /*
 470  * Encode and decode a swap entry:
 471  *      bits 0-1:       present (must be zero)
 472  *      bit  2:         PTE_FILE
 473  *      bits 3-8:       swap type
 474  *      bits 9-57:      swap offset
 475  */
 476 #define __SWP_TYPE_SHIFT        3
 477 #define __SWP_TYPE_BITS         6
 478 #define __SWP_OFFSET_BITS       49
 479 #define __SWP_TYPE_MASK         ((1 << __SWP_TYPE_BITS) - 1)
 480 #define __SWP_OFFSET_SHIFT      (__SWP_TYPE_BITS + __SWP_TYPE_SHIFT)
 481 #define __SWP_OFFSET_MASK       ((1UL << __SWP_OFFSET_BITS) - 1)
 482
 483 #define __swp_type(x)           (((x).val >> __SWP_TYPE_SHIFT) & __SWP_TYPE_MASK)
 484 #define __swp_offset(x)         (((x).val >> __SWP_OFFSET_SHIFT) & __SWP_OFFSET_MASK)
 485 #define __swp_entry(type,offset) ((swp_entry_t) { ((type) << __SWP_TYPE_SHIFT) | ((offset) << __SWP_OFFSET_SHIFT) })
 486
 487 #define __pte_to_swp_entry(pte) ((swp_entry_t) { pte_val(pte) })
 488 #define __swp_entry_to_pte(swp) ((pte_t) { (swp).val })
 489
 490 /*
 491  * Ensure that there are not more swap files than can be encoded in the kernel
 492  * PTEs.
 493  */
 494 #define MAX_SWAPFILES_CHECK() BUILD_BUG_ON(MAX_SWAPFILES_SHIFT > __SWP_TYPE_BITS)
 495
 496 /*
 497  * Encode and decode a file entry:
 498  *      bits 0-1:       present (must be zero)
 499  *      bit  2:         PTE_FILE
 500  *      bits 3-57:      file offset / PAGE_SIZE
 501  */
 502 #define pte_file(pte)           (pte_val(pte) & PTE_FILE)
 503 #define pte_to_pgoff(x)         (pte_val(x) >> 3)
 504 #define pgoff_to_pte(x)         __pte(((x) << 3) | PTE_FILE)
 505
 506 #define PTE_FILE_MAX_BITS       55
 507
 508 extern int kern_addr_valid(unsigned long addr);
 509
 510 #include <asm-generic/pgtable.h>
 511
 512 #define pgtable_cache_init() do { } while (0)
 513
 514 #endif /* !__ASSEMBLY__ */
 515
 516 #endif /* __ASM_PGTABLE_H */