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) 2003 Ralf Baechle 7 */ 8 #ifndef _ASM_PGTABLE_H 9 #define _ASM_PGTABLE_H 10 11 #include <linux/mm_types.h> 12 #include <linux/mmzone.h> 13 #ifdef CONFIG_32BIT 14 #include <asm/pgtable-32.h> 15 #endif 16 #ifdef CONFIG_64BIT 17 #include <asm/pgtable-64.h> 18 #endif 19 20 #include <asm/io.h> 21 #include <asm/pgtable-bits.h> 22 23 struct mm_struct; 24 struct vm_area_struct; 25 26 #define PAGE_NONE __pgprot(_PAGE_PRESENT | _CACHE_CACHABLE_NONCOHERENT) 27 #define PAGE_SHARED __pgprot(_PAGE_PRESENT | _PAGE_WRITE | _PAGE_READ | \ 28 _page_cachable_default) 29 #define PAGE_COPY __pgprot(_PAGE_PRESENT | _PAGE_READ | _PAGE_NO_EXEC | \ 30 _page_cachable_default) 31 #define PAGE_READONLY __pgprot(_PAGE_PRESENT | _PAGE_READ | \ 32 _page_cachable_default) 33 #define PAGE_KERNEL __pgprot(_PAGE_PRESENT | __READABLE | __WRITEABLE | \ 34 _PAGE_GLOBAL | _page_cachable_default) 35 #define PAGE_KERNEL_NC __pgprot(_PAGE_PRESENT | __READABLE | __WRITEABLE | \ 36 _PAGE_GLOBAL | _CACHE_CACHABLE_NONCOHERENT) 37 #define PAGE_USERIO __pgprot(_PAGE_PRESENT | _PAGE_READ | _PAGE_WRITE | \ 38 _page_cachable_default) 39 #define PAGE_KERNEL_UNCACHED __pgprot(_PAGE_PRESENT | __READABLE | \ 40 __WRITEABLE | _PAGE_GLOBAL | _CACHE_UNCACHED) 41 42 /* 43 * If _PAGE_NO_EXEC is not defined, we can't do page protection for 44 * execute, and consider it to be the same as read. Also, write 45 * permissions imply read permissions. This is the closest we can get 46 * by reasonable means.. 47 */ 48 49 /* 50 * Dummy values to fill the table in mmap.c 51 * The real values will be generated at runtime 52 */ 53 #define __P000 __pgprot(0) 54 #define __P001 __pgprot(0) 55 #define __P010 __pgprot(0) 56 #define __P011 __pgprot(0) 57 #define __P100 __pgprot(0) 58 #define __P101 __pgprot(0) 59 #define __P110 __pgprot(0) 60 #define __P111 __pgprot(0) 61 62 #define __S000 __pgprot(0) 63 #define __S001 __pgprot(0) 64 #define __S010 __pgprot(0) 65 #define __S011 __pgprot(0) 66 #define __S100 __pgprot(0) 67 #define __S101 __pgprot(0) 68 #define __S110 __pgprot(0) 69 #define __S111 __pgprot(0) 70 71 extern unsigned long _page_cachable_default; 72 73 /* 74 * ZERO_PAGE is a global shared page that is always zero; used 75 * for zero-mapped memory areas etc.. 76 */ 77 78 extern unsigned long empty_zero_page; 79 extern unsigned long zero_page_mask; 80 81 #define ZERO_PAGE(vaddr) \ 82 (virt_to_page((void *)(empty_zero_page + (((unsigned long)(vaddr)) & zero_page_mask)))) 83 #define __HAVE_COLOR_ZERO_PAGE 84 85 extern void paging_init(void); 86 87 /* 88 * Conversion functions: convert a page and protection to a page entry, 89 * and a page entry and page directory to the page they refer to. 90 */ 91 #define pmd_phys(pmd) virt_to_phys((void *)pmd_val(pmd)) 92 93 #define __pmd_page(pmd) (pfn_to_page(pmd_phys(pmd) >> PAGE_SHIFT)) 94 #ifndef CONFIG_TRANSPARENT_HUGEPAGE 95 #define pmd_page(pmd) __pmd_page(pmd) 96 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ 97 98 #define pmd_page_vaddr(pmd) pmd_val(pmd) 99 100 #define htw_stop() \ 101 do { \ 102 unsigned long flags; \ 103 \ 104 if (cpu_has_htw) { \ 105 local_irq_save(flags); \ 106 if(!raw_current_cpu_data.htw_seq++) { \ 107 write_c0_pwctl(read_c0_pwctl() & \ 108 ~(1 << MIPS_PWCTL_PWEN_SHIFT)); \ 109 back_to_back_c0_hazard(); \ 110 } \ 111 local_irq_restore(flags); \ 112 } \ 113 } while(0) 114 115 #define htw_start() \ 116 do { \ 117 unsigned long flags; \ 118 \ 119 if (cpu_has_htw) { \ 120 local_irq_save(flags); \ 121 if (!--raw_current_cpu_data.htw_seq) { \ 122 write_c0_pwctl(read_c0_pwctl() | \ 123 (1 << MIPS_PWCTL_PWEN_SHIFT)); \ 124 back_to_back_c0_hazard(); \ 125 } \ 126 local_irq_restore(flags); \ 127 } \ 128 } while(0) 129 130 #if defined(CONFIG_PHYS_ADDR_T_64BIT) && defined(CONFIG_CPU_MIPS32) 131 132 #define pte_none(pte) (!(((pte).pte_high) & ~_PAGE_GLOBAL)) 133 #define pte_present(pte) ((pte).pte_low & _PAGE_PRESENT) 134 135 static inline void set_pte(pte_t *ptep, pte_t pte) 136 { 137 ptep->pte_high = pte.pte_high; 138 smp_wmb(); 139 ptep->pte_low = pte.pte_low; 140 141 if (pte.pte_high & _PAGE_GLOBAL) { 142 pte_t *buddy = ptep_buddy(ptep); 143 /* 144 * Make sure the buddy is global too (if it's !none, 145 * it better already be global) 146 */ 147 if (pte_none(*buddy)) 148 buddy->pte_high |= _PAGE_GLOBAL; 149 } 150 } 151 #define set_pte_at(mm, addr, ptep, pteval) set_pte(ptep, pteval) 152 153 static inline void pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep) 154 { 155 pte_t null = __pte(0); 156 157 htw_stop(); 158 /* Preserve global status for the pair */ 159 if (ptep_buddy(ptep)->pte_high & _PAGE_GLOBAL) 160 null.pte_high = _PAGE_GLOBAL; 161 162 set_pte_at(mm, addr, ptep, null); 163 htw_start(); 164 } 165 #else 166 167 #define pte_none(pte) (!(pte_val(pte) & ~_PAGE_GLOBAL)) 168 #define pte_present(pte) (pte_val(pte) & _PAGE_PRESENT) 169 170 /* 171 * Certain architectures need to do special things when pte's 172 * within a page table are directly modified. Thus, the following 173 * hook is made available. 174 */ 175 static inline void set_pte(pte_t *ptep, pte_t pteval) 176 { 177 *ptep = pteval; 178 #if !defined(CONFIG_CPU_R3000) && !defined(CONFIG_CPU_TX39XX) 179 if (pte_val(pteval) & _PAGE_GLOBAL) { 180 pte_t *buddy = ptep_buddy(ptep); 181 /* 182 * Make sure the buddy is global too (if it's !none, 183 * it better already be global) 184 */ 185 #ifdef CONFIG_SMP 186 /* 187 * For SMP, multiple CPUs can race, so we need to do 188 * this atomically. 189 */ 190 #ifdef CONFIG_64BIT 191 #define LL_INSN "lld" 192 #define SC_INSN "scd" 193 #else /* CONFIG_32BIT */ 194 #define LL_INSN "ll" 195 #define SC_INSN "sc" 196 #endif 197 unsigned long page_global = _PAGE_GLOBAL; 198 unsigned long tmp; 199 200 __asm__ __volatile__ ( 201 " .set push\n" 202 " .set noreorder\n" 203 "1: " LL_INSN " %[tmp], %[buddy]\n" 204 " bnez %[tmp], 2f\n" 205 " or %[tmp], %[tmp], %[global]\n" 206 " " SC_INSN " %[tmp], %[buddy]\n" 207 " beqz %[tmp], 1b\n" 208 " nop\n" 209 "2:\n" 210 " .set pop" 211 : [buddy] "+m" (buddy->pte), 212 [tmp] "=&r" (tmp) 213 : [global] "r" (page_global)); 214 #else /* !CONFIG_SMP */ 215 if (pte_none(*buddy)) 216 pte_val(*buddy) = pte_val(*buddy) | _PAGE_GLOBAL; 217 #endif /* CONFIG_SMP */ 218 } 219 #endif 220 } 221 #define set_pte_at(mm, addr, ptep, pteval) set_pte(ptep, pteval) 222 223 static inline void pte_clear(struct mm_struct *mm, unsigned long addr, pte_t *ptep) 224 { 225 htw_stop(); 226 #if !defined(CONFIG_CPU_R3000) && !defined(CONFIG_CPU_TX39XX) 227 /* Preserve global status for the pair */ 228 if (pte_val(*ptep_buddy(ptep)) & _PAGE_GLOBAL) 229 set_pte_at(mm, addr, ptep, __pte(_PAGE_GLOBAL)); 230 else 231 #endif 232 set_pte_at(mm, addr, ptep, __pte(0)); 233 htw_start(); 234 } 235 #endif 236 237 /* 238 * (pmds are folded into puds so this doesn't get actually called, 239 * but the define is needed for a generic inline function.) 240 */ 241 #define set_pmd(pmdptr, pmdval) do { *(pmdptr) = (pmdval); } while(0) 242 243 #ifndef __PAGETABLE_PMD_FOLDED 244 /* 245 * (puds are folded into pgds so this doesn't get actually called, 246 * but the define is needed for a generic inline function.) 247 */ 248 #define set_pud(pudptr, pudval) do { *(pudptr) = (pudval); } while(0) 249 #endif 250 251 #define PGD_T_LOG2 (__builtin_ffs(sizeof(pgd_t)) - 1) 252 #define PMD_T_LOG2 (__builtin_ffs(sizeof(pmd_t)) - 1) 253 #define PTE_T_LOG2 (__builtin_ffs(sizeof(pte_t)) - 1) 254 255 /* 256 * We used to declare this array with size but gcc 3.3 and older are not able 257 * to find that this expression is a constant, so the size is dropped. 258 */ 259 extern pgd_t swapper_pg_dir[]; 260 261 /* 262 * The following only work if pte_present() is true. 263 * Undefined behaviour if not.. 264 */ 265 #if defined(CONFIG_PHYS_ADDR_T_64BIT) && defined(CONFIG_CPU_MIPS32) 266 static inline int pte_write(pte_t pte) { return pte.pte_low & _PAGE_WRITE; } 267 static inline int pte_dirty(pte_t pte) { return pte.pte_low & _PAGE_MODIFIED; } 268 static inline int pte_young(pte_t pte) { return pte.pte_low & _PAGE_ACCESSED; } 269 270 static inline pte_t pte_wrprotect(pte_t pte) 271 { 272 pte.pte_low &= ~_PAGE_WRITE; 273 pte.pte_high &= ~_PAGE_SILENT_WRITE; 274 return pte; 275 } 276 277 static inline pte_t pte_mkclean(pte_t pte) 278 { 279 pte.pte_low &= ~_PAGE_MODIFIED; 280 pte.pte_high &= ~_PAGE_SILENT_WRITE; 281 return pte; 282 } 283 284 static inline pte_t pte_mkold(pte_t pte) 285 { 286 pte.pte_low &= ~_PAGE_ACCESSED; 287 pte.pte_high &= ~_PAGE_SILENT_READ; 288 return pte; 289 } 290 291 static inline pte_t pte_mkwrite(pte_t pte) 292 { 293 pte.pte_low |= _PAGE_WRITE; 294 if (pte.pte_low & _PAGE_MODIFIED) 295 pte.pte_high |= _PAGE_SILENT_WRITE; 296 return pte; 297 } 298 299 static inline pte_t pte_mkdirty(pte_t pte) 300 { 301 pte.pte_low |= _PAGE_MODIFIED; 302 if (pte.pte_low & _PAGE_WRITE) 303 pte.pte_high |= _PAGE_SILENT_WRITE; 304 return pte; 305 } 306 307 static inline pte_t pte_mkyoung(pte_t pte) 308 { 309 pte.pte_low |= _PAGE_ACCESSED; 310 if (pte.pte_low & _PAGE_READ) 311 pte.pte_high |= _PAGE_SILENT_READ; 312 return pte; 313 } 314 #else 315 static inline int pte_write(pte_t pte) { return pte_val(pte) & _PAGE_WRITE; } 316 static inline int pte_dirty(pte_t pte) { return pte_val(pte) & _PAGE_MODIFIED; } 317 static inline int pte_young(pte_t pte) { return pte_val(pte) & _PAGE_ACCESSED; } 318 319 static inline pte_t pte_wrprotect(pte_t pte) 320 { 321 pte_val(pte) &= ~(_PAGE_WRITE | _PAGE_SILENT_WRITE); 322 return pte; 323 } 324 325 static inline pte_t pte_mkclean(pte_t pte) 326 { 327 pte_val(pte) &= ~(_PAGE_MODIFIED | _PAGE_SILENT_WRITE); 328 return pte; 329 } 330 331 static inline pte_t pte_mkold(pte_t pte) 332 { 333 pte_val(pte) &= ~(_PAGE_ACCESSED | _PAGE_SILENT_READ); 334 return pte; 335 } 336 337 static inline pte_t pte_mkwrite(pte_t pte) 338 { 339 pte_val(pte) |= _PAGE_WRITE; 340 if (pte_val(pte) & _PAGE_MODIFIED) 341 pte_val(pte) |= _PAGE_SILENT_WRITE; 342 return pte; 343 } 344 345 static inline pte_t pte_mkdirty(pte_t pte) 346 { 347 pte_val(pte) |= _PAGE_MODIFIED; 348 if (pte_val(pte) & _PAGE_WRITE) 349 pte_val(pte) |= _PAGE_SILENT_WRITE; 350 return pte; 351 } 352 353 static inline pte_t pte_mkyoung(pte_t pte) 354 { 355 pte_val(pte) |= _PAGE_ACCESSED; 356 #if defined(CONFIG_CPU_MIPSR2) || defined(CONFIG_CPU_MIPSR6) 357 if (!(pte_val(pte) & _PAGE_NO_READ)) 358 pte_val(pte) |= _PAGE_SILENT_READ; 359 else 360 #endif 361 if (pte_val(pte) & _PAGE_READ) 362 pte_val(pte) |= _PAGE_SILENT_READ; 363 return pte; 364 } 365 366 #ifdef CONFIG_MIPS_HUGE_TLB_SUPPORT 367 static inline int pte_huge(pte_t pte) { return pte_val(pte) & _PAGE_HUGE; } 368 369 static inline pte_t pte_mkhuge(pte_t pte) 370 { 371 pte_val(pte) |= _PAGE_HUGE; 372 return pte; 373 } 374 #endif /* CONFIG_MIPS_HUGE_TLB_SUPPORT */ 375 #endif 376 static inline int pte_special(pte_t pte) { return 0; } 377 static inline pte_t pte_mkspecial(pte_t pte) { return pte; } 378 379 /* 380 * Macro to make mark a page protection value as "uncacheable". Note 381 * that "protection" is really a misnomer here as the protection value 382 * contains the memory attribute bits, dirty bits, and various other 383 * bits as well. 384 */ 385 #define pgprot_noncached pgprot_noncached 386 387 static inline pgprot_t pgprot_noncached(pgprot_t _prot) 388 { 389 unsigned long prot = pgprot_val(_prot); 390 391 prot = (prot & ~_CACHE_MASK) | _CACHE_UNCACHED; 392 393 return __pgprot(prot); 394 } 395 396 #define pgprot_writecombine pgprot_writecombine 397 398 static inline pgprot_t pgprot_writecombine(pgprot_t _prot) 399 { 400 unsigned long prot = pgprot_val(_prot); 401 402 /* cpu_data[0].writecombine is already shifted by _CACHE_SHIFT */ 403 prot = (prot & ~_CACHE_MASK) | cpu_data[0].writecombine; 404 405 return __pgprot(prot); 406 } 407 408 /* 409 * Conversion functions: convert a page and protection to a page entry, 410 * and a page entry and page directory to the page they refer to. 411 */ 412 #define mk_pte(page, pgprot) pfn_pte(page_to_pfn(page), (pgprot)) 413 414 #if defined(CONFIG_PHYS_ADDR_T_64BIT) && defined(CONFIG_CPU_MIPS32) 415 static inline pte_t pte_modify(pte_t pte, pgprot_t newprot) 416 { 417 pte.pte_low &= (_PAGE_MODIFIED | _PAGE_ACCESSED | _PFNX_MASK); 418 pte.pte_high &= (_PFN_MASK | _CACHE_MASK); 419 pte.pte_low |= pgprot_val(newprot) & ~_PFNX_MASK; 420 pte.pte_high |= pgprot_val(newprot) & ~_PFN_MASK; 421 return pte; 422 } 423 #else 424 static inline pte_t pte_modify(pte_t pte, pgprot_t newprot) 425 { 426 return __pte((pte_val(pte) & _PAGE_CHG_MASK) | pgprot_val(newprot)); 427 } 428 #endif 429 430 431 extern void __update_tlb(struct vm_area_struct *vma, unsigned long address, 432 pte_t pte); 433 extern void __update_cache(struct vm_area_struct *vma, unsigned long address, 434 pte_t pte); 435 436 static inline void update_mmu_cache(struct vm_area_struct *vma, 437 unsigned long address, pte_t *ptep) 438 { 439 pte_t pte = *ptep; 440 __update_tlb(vma, address, pte); 441 __update_cache(vma, address, pte); 442 } 443 444 static inline void update_mmu_cache_pmd(struct vm_area_struct *vma, 445 unsigned long address, pmd_t *pmdp) 446 { 447 pte_t pte = *(pte_t *)pmdp; 448 449 __update_tlb(vma, address, pte); 450 } 451 452 #define kern_addr_valid(addr) (1) 453 454 #ifdef CONFIG_PHYS_ADDR_T_64BIT 455 extern int remap_pfn_range(struct vm_area_struct *vma, unsigned long from, unsigned long pfn, unsigned long size, pgprot_t prot); 456 457 static inline int io_remap_pfn_range(struct vm_area_struct *vma, 458 unsigned long vaddr, 459 unsigned long pfn, 460 unsigned long size, 461 pgprot_t prot) 462 { 463 phys_addr_t phys_addr_high = fixup_bigphys_addr(pfn << PAGE_SHIFT, size); 464 return remap_pfn_range(vma, vaddr, phys_addr_high >> PAGE_SHIFT, size, prot); 465 } 466 #define io_remap_pfn_range io_remap_pfn_range 467 #endif 468 469 #ifdef CONFIG_TRANSPARENT_HUGEPAGE 470 471 extern int has_transparent_hugepage(void); 472 473 static inline int pmd_trans_huge(pmd_t pmd) 474 { 475 return !!(pmd_val(pmd) & _PAGE_HUGE); 476 } 477 478 static inline pmd_t pmd_mkhuge(pmd_t pmd) 479 { 480 pmd_val(pmd) |= _PAGE_HUGE; 481 482 return pmd; 483 } 484 485 extern void set_pmd_at(struct mm_struct *mm, unsigned long addr, 486 pmd_t *pmdp, pmd_t pmd); 487 488 #define __HAVE_ARCH_PMD_WRITE 489 static inline int pmd_write(pmd_t pmd) 490 { 491 return !!(pmd_val(pmd) & _PAGE_WRITE); 492 } 493 494 static inline pmd_t pmd_wrprotect(pmd_t pmd) 495 { 496 pmd_val(pmd) &= ~(_PAGE_WRITE | _PAGE_SILENT_WRITE); 497 return pmd; 498 } 499 500 static inline pmd_t pmd_mkwrite(pmd_t pmd) 501 { 502 pmd_val(pmd) |= _PAGE_WRITE; 503 if (pmd_val(pmd) & _PAGE_MODIFIED) 504 pmd_val(pmd) |= _PAGE_SILENT_WRITE; 505 506 return pmd; 507 } 508 509 static inline int pmd_dirty(pmd_t pmd) 510 { 511 return !!(pmd_val(pmd) & _PAGE_MODIFIED); 512 } 513 514 static inline pmd_t pmd_mkclean(pmd_t pmd) 515 { 516 pmd_val(pmd) &= ~(_PAGE_MODIFIED | _PAGE_SILENT_WRITE); 517 return pmd; 518 } 519 520 static inline pmd_t pmd_mkdirty(pmd_t pmd) 521 { 522 pmd_val(pmd) |= _PAGE_MODIFIED; 523 if (pmd_val(pmd) & _PAGE_WRITE) 524 pmd_val(pmd) |= _PAGE_SILENT_WRITE; 525 526 return pmd; 527 } 528 529 static inline int pmd_young(pmd_t pmd) 530 { 531 return !!(pmd_val(pmd) & _PAGE_ACCESSED); 532 } 533 534 static inline pmd_t pmd_mkold(pmd_t pmd) 535 { 536 pmd_val(pmd) &= ~(_PAGE_ACCESSED|_PAGE_SILENT_READ); 537 538 return pmd; 539 } 540 541 static inline pmd_t pmd_mkyoung(pmd_t pmd) 542 { 543 pmd_val(pmd) |= _PAGE_ACCESSED; 544 545 #if defined(CONFIG_CPU_MIPSR2) || defined(CONFIG_CPU_MIPSR6) 546 if (!(pmd_val(pmd) & _PAGE_NO_READ)) 547 pmd_val(pmd) |= _PAGE_SILENT_READ; 548 else 549 #endif 550 if (pmd_val(pmd) & _PAGE_READ) 551 pmd_val(pmd) |= _PAGE_SILENT_READ; 552 553 return pmd; 554 } 555 556 /* Extern to avoid header file madness */ 557 extern pmd_t mk_pmd(struct page *page, pgprot_t prot); 558 559 static inline unsigned long pmd_pfn(pmd_t pmd) 560 { 561 return pmd_val(pmd) >> _PFN_SHIFT; 562 } 563 564 static inline struct page *pmd_page(pmd_t pmd) 565 { 566 if (pmd_trans_huge(pmd)) 567 return pfn_to_page(pmd_pfn(pmd)); 568 569 return pfn_to_page(pmd_phys(pmd) >> PAGE_SHIFT); 570 } 571 572 static inline pmd_t pmd_modify(pmd_t pmd, pgprot_t newprot) 573 { 574 pmd_val(pmd) = (pmd_val(pmd) & _PAGE_CHG_MASK) | pgprot_val(newprot); 575 return pmd; 576 } 577 578 static inline pmd_t pmd_mknotpresent(pmd_t pmd) 579 { 580 pmd_val(pmd) &= ~(_PAGE_PRESENT | _PAGE_VALID | _PAGE_DIRTY); 581 582 return pmd; 583 } 584 585 /* 586 * The generic version pmdp_huge_get_and_clear uses a version of pmd_clear() with a 587 * different prototype. 588 */ 589 #define __HAVE_ARCH_PMDP_HUGE_GET_AND_CLEAR 590 static inline pmd_t pmdp_huge_get_and_clear(struct mm_struct *mm, 591 unsigned long address, pmd_t *pmdp) 592 { 593 pmd_t old = *pmdp; 594 595 pmd_clear(pmdp); 596 597 return old; 598 } 599 600 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ 601 602 #include <asm-generic/pgtable.h> 603 604 /* 605 * uncached accelerated TLB map for video memory access 606 */ 607 #ifdef CONFIG_CPU_SUPPORTS_UNCACHED_ACCELERATED 608 #define __HAVE_PHYS_MEM_ACCESS_PROT 609 610 struct file; 611 pgprot_t phys_mem_access_prot(struct file *file, unsigned long pfn, 612 unsigned long size, pgprot_t vma_prot); 613 int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn, 614 unsigned long size, pgprot_t *vma_prot); 615 #endif 616 617 /* 618 * We provide our own get_unmapped area to cope with the virtual aliasing 619 * constraints placed on us by the cache architecture. 620 */ 621 #define HAVE_ARCH_UNMAPPED_AREA 622 #define HAVE_ARCH_UNMAPPED_AREA_TOPDOWN 623 624 /* 625 * No page table caches to initialise 626 */ 627 #define pgtable_cache_init() do { } while (0) 628 629 #endif /* _ASM_PGTABLE_H */ 630