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 */ 503