1 /* SPDX-License-Identifier: GPL-2.0 */ 2 #ifndef _LINUX_PGTABLE_H 3 #define _LINUX_PGTABLE_H 4 5 #include <linux/pfn.h> 6 #include <asm/pgtable.h> 7 8 #ifndef __ASSEMBLY__ 9 #ifdef CONFIG_MMU 10 11 #include <linux/mm_types.h> 12 #include <linux/bug.h> 13 #include <linux/errno.h> 14 #include <asm-generic/pgtable_uffd.h> 15 16 #if 5 - defined(__PAGETABLE_P4D_FOLDED) - defined(__PAGETABLE_PUD_FOLDED) - \ 17 defined(__PAGETABLE_PMD_FOLDED) != CONFIG_PGTABLE_LEVELS 18 #error CONFIG_PGTABLE_LEVELS is not consistent with __PAGETABLE_{P4D,PUD,PMD}_FOLDED 19 #endif 20 21 /* 22 * On almost all architectures and configurations, 0 can be used as the 23 * upper ceiling to free_pgtables(): on many architectures it has the same 24 * effect as using TASK_SIZE. However, there is one configuration which 25 * must impose a more careful limit, to avoid freeing kernel pgtables. 26 */ 27 #ifndef USER_PGTABLES_CEILING 28 #define USER_PGTABLES_CEILING 0UL 29 #endif 30 31 /* 32 * A page table page can be thought of an array like this: pXd_t[PTRS_PER_PxD] 33 * 34 * The pXx_index() functions return the index of the entry in the page 35 * table page which would control the given virtual address 36 * 37 * As these functions may be used by the same code for different levels of 38 * the page table folding, they are always available, regardless of 39 * CONFIG_PGTABLE_LEVELS value. For the folded levels they simply return 0 40 * because in such cases PTRS_PER_PxD equals 1. 41 */ 42 43 static inline unsigned long pte_index(unsigned long address) 44 { 45 return (address >> PAGE_SHIFT) & (PTRS_PER_PTE - 1); 46 } 47 48 #ifndef pmd_index 49 static inline unsigned long pmd_index(unsigned long address) 50 { 51 return (address >> PMD_SHIFT) & (PTRS_PER_PMD - 1); 52 } 53 #define pmd_index pmd_index 54 #endif 55 56 #ifndef pud_index 57 static inline unsigned long pud_index(unsigned long address) 58 { 59 return (address >> PUD_SHIFT) & (PTRS_PER_PUD - 1); 60 } 61 #define pud_index pud_index 62 #endif 63 64 #ifndef pgd_index 65 /* Must be a compile-time constant, so implement it as a macro */ 66 #define pgd_index(a) (((a) >> PGDIR_SHIFT) & (PTRS_PER_PGD - 1)) 67 #endif 68 69 #ifndef pte_offset_kernel 70 static inline pte_t *pte_offset_kernel(pmd_t *pmd, unsigned long address) 71 { 72 return (pte_t *)pmd_page_vaddr(*pmd) + pte_index(address); 73 } 74 #define pte_offset_kernel pte_offset_kernel 75 #endif 76 77 #if defined(CONFIG_HIGHPTE) 78 #define pte_offset_map(dir, address) \ 79 ((pte_t *)kmap_atomic(pmd_page(*(dir))) + \ 80 pte_index((address))) 81 #define pte_unmap(pte) kunmap_atomic((pte)) 82 #else 83 #define pte_offset_map(dir, address) pte_offset_kernel((dir), (address)) 84 #define pte_unmap(pte) ((void)(pte)) /* NOP */ 85 #endif 86 87 /* Find an entry in the second-level page table.. */ 88 #ifndef pmd_offset 89 static inline pmd_t *pmd_offset(pud_t *pud, unsigned long address) 90 { 91 return (pmd_t *)pud_page_vaddr(*pud) + pmd_index(address); 92 } 93 #define pmd_offset pmd_offset 94 #endif 95 96 #ifndef pud_offset 97 static inline pud_t *pud_offset(p4d_t *p4d, unsigned long address) 98 { 99 return (pud_t *)p4d_page_vaddr(*p4d) + pud_index(address); 100 } 101 #define pud_offset pud_offset 102 #endif 103 104 static inline pgd_t *pgd_offset_pgd(pgd_t *pgd, unsigned long address) 105 { 106 return (pgd + pgd_index(address)); 107 }; 108 109 /* 110 * a shortcut to get a pgd_t in a given mm 111 */ 112 #ifndef pgd_offset 113 #define pgd_offset(mm, address) pgd_offset_pgd((mm)->pgd, (address)) 114 #endif 115 116 /* 117 * a shortcut which implies the use of the kernel's pgd, instead 118 * of a process's 119 */ 120 #ifndef pgd_offset_k 121 #define pgd_offset_k(address) pgd_offset(&init_mm, (address)) 122 #endif 123 124 /* 125 * In many cases it is known that a virtual address is mapped at PMD or PTE 126 * level, so instead of traversing all the page table levels, we can get a 127 * pointer to the PMD entry in user or kernel page table or translate a virtual 128 * address to the pointer in the PTE in the kernel page tables with simple 129 * helpers. 130 */ 131 static inline pmd_t *pmd_off(struct mm_struct *mm, unsigned long va) 132 { 133 return pmd_offset(pud_offset(p4d_offset(pgd_offset(mm, va), va), va), va); 134 } 135 136 static inline pmd_t *pmd_off_k(unsigned long va) 137 { 138 return pmd_offset(pud_offset(p4d_offset(pgd_offset_k(va), va), va), va); 139 } 140 141 static inline pte_t *virt_to_kpte(unsigned long vaddr) 142 { 143 pmd_t *pmd = pmd_off_k(vaddr); 144 145 return pmd_none(*pmd) ? NULL : pte_offset_kernel(pmd, vaddr); 146 } 147 148 #ifndef __HAVE_ARCH_PTEP_SET_ACCESS_FLAGS 149 extern int ptep_set_access_flags(struct vm_area_struct *vma, 150 unsigned long address, pte_t *ptep, 151 pte_t entry, int dirty); 152 #endif 153 154 #ifndef __HAVE_ARCH_PMDP_SET_ACCESS_FLAGS 155 #ifdef CONFIG_TRANSPARENT_HUGEPAGE 156 extern int pmdp_set_access_flags(struct vm_area_struct *vma, 157 unsigned long address, pmd_t *pmdp, 158 pmd_t entry, int dirty); 159 extern int pudp_set_access_flags(struct vm_area_struct *vma, 160 unsigned long address, pud_t *pudp, 161 pud_t entry, int dirty); 162 #else 163 static inline int pmdp_set_access_flags(struct vm_area_struct *vma, 164 unsigned long address, pmd_t *pmdp, 165 pmd_t entry, int dirty) 166 { 167 BUILD_BUG(); 168 return 0; 169 } 170 static inline int pudp_set_access_flags(struct vm_area_struct *vma, 171 unsigned long address, pud_t *pudp, 172 pud_t entry, int dirty) 173 { 174 BUILD_BUG(); 175 return 0; 176 } 177 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ 178 #endif 179 180 #ifndef __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG 181 static inline int ptep_test_and_clear_young(struct vm_area_struct *vma, 182 unsigned long address, 183 pte_t *ptep) 184 { 185 pte_t pte = *ptep; 186 int r = 1; 187 if (!pte_young(pte)) 188 r = 0; 189 else 190 set_pte_at(vma->vm_mm, address, ptep, pte_mkold(pte)); 191 return r; 192 } 193 #endif 194 195 #ifndef __HAVE_ARCH_PMDP_TEST_AND_CLEAR_YOUNG 196 #ifdef CONFIG_TRANSPARENT_HUGEPAGE 197 static inline int pmdp_test_and_clear_young(struct vm_area_struct *vma, 198 unsigned long address, 199 pmd_t *pmdp) 200 { 201 pmd_t pmd = *pmdp; 202 int r = 1; 203 if (!pmd_young(pmd)) 204 r = 0; 205 else 206 set_pmd_at(vma->vm_mm, address, pmdp, pmd_mkold(pmd)); 207 return r; 208 } 209 #else 210 static inline int pmdp_test_and_clear_young(struct vm_area_struct *vma, 211 unsigned long address, 212 pmd_t *pmdp) 213 { 214 BUILD_BUG(); 215 return 0; 216 } 217 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ 218 #endif 219 220 #ifndef __HAVE_ARCH_PTEP_CLEAR_YOUNG_FLUSH 221 int ptep_clear_flush_young(struct vm_area_struct *vma, 222 unsigned long address, pte_t *ptep); 223 #endif 224 225 #ifndef __HAVE_ARCH_PMDP_CLEAR_YOUNG_FLUSH 226 #ifdef CONFIG_TRANSPARENT_HUGEPAGE 227 extern int pmdp_clear_flush_young(struct vm_area_struct *vma, 228 unsigned long address, pmd_t *pmdp); 229 #else 230 /* 231 * Despite relevant to THP only, this API is called from generic rmap code 232 * under PageTransHuge(), hence needs a dummy implementation for !THP 233 */ 234 static inline int pmdp_clear_flush_young(struct vm_area_struct *vma, 235 unsigned long address, pmd_t *pmdp) 236 { 237 BUILD_BUG(); 238 return 0; 239 } 240 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ 241 #endif 242 243 #ifndef __HAVE_ARCH_PTEP_GET_AND_CLEAR 244 static inline pte_t ptep_get_and_clear(struct mm_struct *mm, 245 unsigned long address, 246 pte_t *ptep) 247 { 248 pte_t pte = *ptep; 249 pte_clear(mm, address, ptep); 250 return pte; 251 } 252 #endif 253 254 #ifndef __HAVE_ARCH_PTEP_GET 255 static inline pte_t ptep_get(pte_t *ptep) 256 { 257 return READ_ONCE(*ptep); 258 } 259 #endif 260 261 #ifdef CONFIG_GUP_GET_PTE_LOW_HIGH 262 /* 263 * WARNING: only to be used in the get_user_pages_fast() implementation. 264 * 265 * With get_user_pages_fast(), we walk down the pagetables without taking any 266 * locks. For this we would like to load the pointers atomically, but sometimes 267 * that is not possible (e.g. without expensive cmpxchg8b on x86_32 PAE). What 268 * we do have is the guarantee that a PTE will only either go from not present 269 * to present, or present to not present or both -- it will not switch to a 270 * completely different present page without a TLB flush in between; something 271 * that we are blocking by holding interrupts off. 272 * 273 * Setting ptes from not present to present goes: 274 * 275 * ptep->pte_high = h; 276 * smp_wmb(); 277 * ptep->pte_low = l; 278 * 279 * And present to not present goes: 280 * 281 * ptep->pte_low = 0; 282 * smp_wmb(); 283 * ptep->pte_high = 0; 284 * 285 * We must ensure here that the load of pte_low sees 'l' IFF pte_high sees 'h'. 286 * We load pte_high *after* loading pte_low, which ensures we don't see an older 287 * value of pte_high. *Then* we recheck pte_low, which ensures that we haven't 288 * picked up a changed pte high. We might have gotten rubbish values from 289 * pte_low and pte_high, but we are guaranteed that pte_low will not have the 290 * present bit set *unless* it is 'l'. Because get_user_pages_fast() only 291 * operates on present ptes we're safe. 292 */ 293 static inline pte_t ptep_get_lockless(pte_t *ptep) 294 { 295 pte_t pte; 296 297 do { 298 pte.pte_low = ptep->pte_low; 299 smp_rmb(); 300 pte.pte_high = ptep->pte_high; 301 smp_rmb(); 302 } while (unlikely(pte.pte_low != ptep->pte_low)); 303 304 return pte; 305 } 306 #else /* CONFIG_GUP_GET_PTE_LOW_HIGH */ 307 /* 308 * We require that the PTE can be read atomically. 309 */ 310 static inline pte_t ptep_get_lockless(pte_t *ptep) 311 { 312 return ptep_get(ptep); 313 } 314 #endif /* CONFIG_GUP_GET_PTE_LOW_HIGH */ 315 316 #ifdef CONFIG_TRANSPARENT_HUGEPAGE 317 #ifndef __HAVE_ARCH_PMDP_HUGE_GET_AND_CLEAR 318 static inline pmd_t pmdp_huge_get_and_clear(struct mm_struct *mm, 319 unsigned long address, 320 pmd_t *pmdp) 321 { 322 pmd_t pmd = *pmdp; 323 pmd_clear(pmdp); 324 return pmd; 325 } 326 #endif /* __HAVE_ARCH_PMDP_HUGE_GET_AND_CLEAR */ 327 #ifndef __HAVE_ARCH_PUDP_HUGE_GET_AND_CLEAR 328 static inline pud_t pudp_huge_get_and_clear(struct mm_struct *mm, 329 unsigned long address, 330 pud_t *pudp) 331 { 332 pud_t pud = *pudp; 333 334 pud_clear(pudp); 335 return pud; 336 } 337 #endif /* __HAVE_ARCH_PUDP_HUGE_GET_AND_CLEAR */ 338 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ 339 340 #ifdef CONFIG_TRANSPARENT_HUGEPAGE 341 #ifndef __HAVE_ARCH_PMDP_HUGE_GET_AND_CLEAR_FULL 342 static inline pmd_t pmdp_huge_get_and_clear_full(struct vm_area_struct *vma, 343 unsigned long address, pmd_t *pmdp, 344 int full) 345 { 346 return pmdp_huge_get_and_clear(vma->vm_mm, address, pmdp); 347 } 348 #endif 349 350 #ifndef __HAVE_ARCH_PUDP_HUGE_GET_AND_CLEAR_FULL 351 static inline pud_t pudp_huge_get_and_clear_full(struct mm_struct *mm, 352 unsigned long address, pud_t *pudp, 353 int full) 354 { 355 return pudp_huge_get_and_clear(mm, address, pudp); 356 } 357 #endif 358 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ 359 360 #ifndef __HAVE_ARCH_PTEP_GET_AND_CLEAR_FULL 361 static inline pte_t ptep_get_and_clear_full(struct mm_struct *mm, 362 unsigned long address, pte_t *ptep, 363 int full) 364 { 365 pte_t pte; 366 pte = ptep_get_and_clear(mm, address, ptep); 367 return pte; 368 } 369 #endif 370 371 372 /* 373 * If two threads concurrently fault at the same page, the thread that 374 * won the race updates the PTE and its local TLB/Cache. The other thread 375 * gives up, simply does nothing, and continues; on architectures where 376 * software can update TLB, local TLB can be updated here to avoid next page 377 * fault. This function updates TLB only, do nothing with cache or others. 378 * It is the difference with function update_mmu_cache. 379 */ 380 #ifndef __HAVE_ARCH_UPDATE_MMU_TLB 381 static inline void update_mmu_tlb(struct vm_area_struct *vma, 382 unsigned long address, pte_t *ptep) 383 { 384 } 385 #define __HAVE_ARCH_UPDATE_MMU_TLB 386 #endif 387 388 /* 389 * Some architectures may be able to avoid expensive synchronization 390 * primitives when modifications are made to PTE's which are already 391 * not present, or in the process of an address space destruction. 392 */ 393 #ifndef __HAVE_ARCH_PTE_CLEAR_NOT_PRESENT_FULL 394 static inline void pte_clear_not_present_full(struct mm_struct *mm, 395 unsigned long address, 396 pte_t *ptep, 397 int full) 398 { 399 pte_clear(mm, address, ptep); 400 } 401 #endif 402 403 #ifndef __HAVE_ARCH_PTEP_CLEAR_FLUSH 404 extern pte_t ptep_clear_flush(struct vm_area_struct *vma, 405 unsigned long address, 406 pte_t *ptep); 407 #endif 408 409 #ifndef __HAVE_ARCH_PMDP_HUGE_CLEAR_FLUSH 410 extern pmd_t pmdp_huge_clear_flush(struct vm_area_struct *vma, 411 unsigned long address, 412 pmd_t *pmdp); 413 extern pud_t pudp_huge_clear_flush(struct vm_area_struct *vma, 414 unsigned long address, 415 pud_t *pudp); 416 #endif 417 418 #ifndef __HAVE_ARCH_PTEP_SET_WRPROTECT 419 struct mm_struct; 420 static inline void ptep_set_wrprotect(struct mm_struct *mm, unsigned long address, pte_t *ptep) 421 { 422 pte_t old_pte = *ptep; 423 set_pte_at(mm, address, ptep, pte_wrprotect(old_pte)); 424 } 425 #endif 426 427 /* 428 * On some architectures hardware does not set page access bit when accessing 429 * memory page, it is responsibility of software setting this bit. It brings 430 * out extra page fault penalty to track page access bit. For optimization page 431 * access bit can be set during all page fault flow on these arches. 432 * To be differentiate with macro pte_mkyoung, this macro is used on platforms 433 * where software maintains page access bit. 434 */ 435 #ifndef pte_savedwrite 436 #define pte_savedwrite pte_write 437 #endif 438 439 #ifndef pte_mk_savedwrite 440 #define pte_mk_savedwrite pte_mkwrite 441 #endif 442 443 #ifndef pte_clear_savedwrite 444 #define pte_clear_savedwrite pte_wrprotect 445 #endif 446 447 #ifndef pmd_savedwrite 448 #define pmd_savedwrite pmd_write 449 #endif 450 451 #ifndef pmd_mk_savedwrite 452 #define pmd_mk_savedwrite pmd_mkwrite 453 #endif 454 455 #ifndef pmd_clear_savedwrite 456 #define pmd_clear_savedwrite pmd_wrprotect 457 #endif 458 459 #ifndef __HAVE_ARCH_PMDP_SET_WRPROTECT 460 #ifdef CONFIG_TRANSPARENT_HUGEPAGE 461 static inline void pmdp_set_wrprotect(struct mm_struct *mm, 462 unsigned long address, pmd_t *pmdp) 463 { 464 pmd_t old_pmd = *pmdp; 465 set_pmd_at(mm, address, pmdp, pmd_wrprotect(old_pmd)); 466 } 467 #else 468 static inline void pmdp_set_wrprotect(struct mm_struct *mm, 469 unsigned long address, pmd_t *pmdp) 470 { 471 BUILD_BUG(); 472 } 473 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ 474 #endif 475 #ifndef __HAVE_ARCH_PUDP_SET_WRPROTECT 476 #ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD 477 static inline void pudp_set_wrprotect(struct mm_struct *mm, 478 unsigned long address, pud_t *pudp) 479 { 480 pud_t old_pud = *pudp; 481 482 set_pud_at(mm, address, pudp, pud_wrprotect(old_pud)); 483 } 484 #else 485 static inline void pudp_set_wrprotect(struct mm_struct *mm, 486 unsigned long address, pud_t *pudp) 487 { 488 BUILD_BUG(); 489 } 490 #endif /* CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD */ 491 #endif 492 493 #ifndef pmdp_collapse_flush 494 #ifdef CONFIG_TRANSPARENT_HUGEPAGE 495 extern pmd_t pmdp_collapse_flush(struct vm_area_struct *vma, 496 unsigned long address, pmd_t *pmdp); 497 #else 498 static inline pmd_t pmdp_collapse_flush(struct vm_area_struct *vma, 499 unsigned long address, 500 pmd_t *pmdp) 501 { 502 BUILD_BUG(); 503 return *pmdp; 504 } 505 #define pmdp_collapse_flush pmdp_collapse_flush 506 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ 507 #endif 508 509 #ifndef __HAVE_ARCH_PGTABLE_DEPOSIT 510 extern void pgtable_trans_huge_deposit(struct mm_struct *mm, pmd_t *pmdp, 511 pgtable_t pgtable); 512 #endif 513 514 #ifndef __HAVE_ARCH_PGTABLE_WITHDRAW 515 extern pgtable_t pgtable_trans_huge_withdraw(struct mm_struct *mm, pmd_t *pmdp); 516 #endif 517 518 #ifdef CONFIG_TRANSPARENT_HUGEPAGE 519 /* 520 * This is an implementation of pmdp_establish() that is only suitable for an 521 * architecture that doesn't have hardware dirty/accessed bits. In this case we 522 * can't race with CPU which sets these bits and non-atomic approach is fine. 523 */ 524 static inline pmd_t generic_pmdp_establish(struct vm_area_struct *vma, 525 unsigned long address, pmd_t *pmdp, pmd_t pmd) 526 { 527 pmd_t old_pmd = *pmdp; 528 set_pmd_at(vma->vm_mm, address, pmdp, pmd); 529 return old_pmd; 530 } 531 #endif 532 533 #ifndef __HAVE_ARCH_PMDP_INVALIDATE 534 extern pmd_t pmdp_invalidate(struct vm_area_struct *vma, unsigned long address, 535 pmd_t *pmdp); 536 #endif 537 538 #ifndef __HAVE_ARCH_PTE_SAME 539 static inline int pte_same(pte_t pte_a, pte_t pte_b) 540 { 541 return pte_val(pte_a) == pte_val(pte_b); 542 } 543 #endif 544 545 #ifndef __HAVE_ARCH_PTE_UNUSED 546 /* 547 * Some architectures provide facilities to virtualization guests 548 * so that they can flag allocated pages as unused. This allows the 549 * host to transparently reclaim unused pages. This function returns 550 * whether the pte's page is unused. 551 */ 552 static inline int pte_unused(pte_t pte) 553 { 554 return 0; 555 } 556 #endif 557 558 #ifndef pte_access_permitted 559 #define pte_access_permitted(pte, write) \ 560 (pte_present(pte) && (!(write) || pte_write(pte))) 561 #endif 562 563 #ifndef pmd_access_permitted 564 #define pmd_access_permitted(pmd, write) \ 565 (pmd_present(pmd) && (!(write) || pmd_write(pmd))) 566 #endif 567 568 #ifndef pud_access_permitted 569 #define pud_access_permitted(pud, write) \ 570 (pud_present(pud) && (!(write) || pud_write(pud))) 571 #endif 572 573 #ifndef p4d_access_permitted 574 #define p4d_access_permitted(p4d, write) \ 575 (p4d_present(p4d) && (!(write) || p4d_write(p4d))) 576 #endif 577 578 #ifndef pgd_access_permitted 579 #define pgd_access_permitted(pgd, write) \ 580 (pgd_present(pgd) && (!(write) || pgd_write(pgd))) 581 #endif 582 583 #ifndef __HAVE_ARCH_PMD_SAME 584 static inline int pmd_same(pmd_t pmd_a, pmd_t pmd_b) 585 { 586 return pmd_val(pmd_a) == pmd_val(pmd_b); 587 } 588 589 static inline int pud_same(pud_t pud_a, pud_t pud_b) 590 { 591 return pud_val(pud_a) == pud_val(pud_b); 592 } 593 #endif 594 595 #ifndef __HAVE_ARCH_P4D_SAME 596 static inline int p4d_same(p4d_t p4d_a, p4d_t p4d_b) 597 { 598 return p4d_val(p4d_a) == p4d_val(p4d_b); 599 } 600 #endif 601 602 #ifndef __HAVE_ARCH_PGD_SAME 603 static inline int pgd_same(pgd_t pgd_a, pgd_t pgd_b) 604 { 605 return pgd_val(pgd_a) == pgd_val(pgd_b); 606 } 607 #endif 608 609 /* 610 * Use set_p*_safe(), and elide TLB flushing, when confident that *no* 611 * TLB flush will be required as a result of the "set". For example, use 612 * in scenarios where it is known ahead of time that the routine is 613 * setting non-present entries, or re-setting an existing entry to the 614 * same value. Otherwise, use the typical "set" helpers and flush the 615 * TLB. 616 */ 617 #define set_pte_safe(ptep, pte) \ 618 ({ \ 619 WARN_ON_ONCE(pte_present(*ptep) && !pte_same(*ptep, pte)); \ 620 set_pte(ptep, pte); \ 621 }) 622 623 #define set_pmd_safe(pmdp, pmd) \ 624 ({ \ 625 WARN_ON_ONCE(pmd_present(*pmdp) && !pmd_same(*pmdp, pmd)); \ 626 set_pmd(pmdp, pmd); \ 627 }) 628 629 #define set_pud_safe(pudp, pud) \ 630 ({ \ 631 WARN_ON_ONCE(pud_present(*pudp) && !pud_same(*pudp, pud)); \ 632 set_pud(pudp, pud); \ 633 }) 634 635 #define set_p4d_safe(p4dp, p4d) \ 636 ({ \ 637 WARN_ON_ONCE(p4d_present(*p4dp) && !p4d_same(*p4dp, p4d)); \ 638 set_p4d(p4dp, p4d); \ 639 }) 640 641 #define set_pgd_safe(pgdp, pgd) \ 642 ({ \ 643 WARN_ON_ONCE(pgd_present(*pgdp) && !pgd_same(*pgdp, pgd)); \ 644 set_pgd(pgdp, pgd); \ 645 }) 646 647 #ifndef __HAVE_ARCH_DO_SWAP_PAGE 648 /* 649 * Some architectures support metadata associated with a page. When a 650 * page is being swapped out, this metadata must be saved so it can be 651 * restored when the page is swapped back in. SPARC M7 and newer 652 * processors support an ADI (Application Data Integrity) tag for the 653 * page as metadata for the page. arch_do_swap_page() can restore this 654 * metadata when a page is swapped back in. 655 */ 656 static inline void arch_do_swap_page(struct mm_struct *mm, 657 struct vm_area_struct *vma, 658 unsigned long addr, 659 pte_t pte, pte_t oldpte) 660 { 661 662 } 663 #endif 664 665 #ifndef __HAVE_ARCH_UNMAP_ONE 666 /* 667 * Some architectures support metadata associated with a page. When a 668 * page is being swapped out, this metadata must be saved so it can be 669 * restored when the page is swapped back in. SPARC M7 and newer 670 * processors support an ADI (Application Data Integrity) tag for the 671 * page as metadata for the page. arch_unmap_one() can save this 672 * metadata on a swap-out of a page. 673 */ 674 static inline int arch_unmap_one(struct mm_struct *mm, 675 struct vm_area_struct *vma, 676 unsigned long addr, 677 pte_t orig_pte) 678 { 679 return 0; 680 } 681 #endif 682 683 /* 684 * Allow architectures to preserve additional metadata associated with 685 * swapped-out pages. The corresponding __HAVE_ARCH_SWAP_* macros and function 686 * prototypes must be defined in the arch-specific asm/pgtable.h file. 687 */ 688 #ifndef __HAVE_ARCH_PREPARE_TO_SWAP 689 static inline int arch_prepare_to_swap(struct page *page) 690 { 691 return 0; 692 } 693 #endif 694 695 #ifndef __HAVE_ARCH_SWAP_INVALIDATE 696 static inline void arch_swap_invalidate_page(int type, pgoff_t offset) 697 { 698 } 699 700 static inline void arch_swap_invalidate_area(int type) 701 { 702 } 703 #endif 704 705 #ifndef __HAVE_ARCH_SWAP_RESTORE 706 static inline void arch_swap_restore(swp_entry_t entry, struct page *page) 707 { 708 } 709 #endif 710 711 #ifndef __HAVE_ARCH_PGD_OFFSET_GATE 712 #define pgd_offset_gate(mm, addr) pgd_offset(mm, addr) 713 #endif 714 715 #ifndef __HAVE_ARCH_MOVE_PTE 716 #define move_pte(pte, prot, old_addr, new_addr) (pte) 717 #endif 718 719 #ifndef pte_accessible 720 # define pte_accessible(mm, pte) ((void)(pte), 1) 721 #endif 722 723 #ifndef flush_tlb_fix_spurious_fault 724 #define flush_tlb_fix_spurious_fault(vma, address) flush_tlb_page(vma, address) 725 #endif 726 727 /* 728 * When walking page tables, get the address of the next boundary, 729 * or the end address of the range if that comes earlier. Although no 730 * vma end wraps to 0, rounded up __boundary may wrap to 0 throughout. 731 */ 732 733 #define pgd_addr_end(addr, end) \ 734 ({ unsigned long __boundary = ((addr) + PGDIR_SIZE) & PGDIR_MASK; \ 735 (__boundary - 1 < (end) - 1)? __boundary: (end); \ 736 }) 737 738 #ifndef p4d_addr_end 739 #define p4d_addr_end(addr, end) \ 740 ({ unsigned long __boundary = ((addr) + P4D_SIZE) & P4D_MASK; \ 741 (__boundary - 1 < (end) - 1)? __boundary: (end); \ 742 }) 743 #endif 744 745 #ifndef pud_addr_end 746 #define pud_addr_end(addr, end) \ 747 ({ unsigned long __boundary = ((addr) + PUD_SIZE) & PUD_MASK; \ 748 (__boundary - 1 < (end) - 1)? __boundary: (end); \ 749 }) 750 #endif 751 752 #ifndef pmd_addr_end 753 #define pmd_addr_end(addr, end) \ 754 ({ unsigned long __boundary = ((addr) + PMD_SIZE) & PMD_MASK; \ 755 (__boundary - 1 < (end) - 1)? __boundary: (end); \ 756 }) 757 #endif 758 759 /* 760 * When walking page tables, we usually want to skip any p?d_none entries; 761 * and any p?d_bad entries - reporting the error before resetting to none. 762 * Do the tests inline, but report and clear the bad entry in mm/memory.c. 763 */ 764 void pgd_clear_bad(pgd_t *); 765 766 #ifndef __PAGETABLE_P4D_FOLDED 767 void p4d_clear_bad(p4d_t *); 768 #else 769 #define p4d_clear_bad(p4d) do { } while (0) 770 #endif 771 772 #ifndef __PAGETABLE_PUD_FOLDED 773 void pud_clear_bad(pud_t *); 774 #else 775 #define pud_clear_bad(p4d) do { } while (0) 776 #endif 777 778 void pmd_clear_bad(pmd_t *); 779 780 static inline int pgd_none_or_clear_bad(pgd_t *pgd) 781 { 782 if (pgd_none(*pgd)) 783 return 1; 784 if (unlikely(pgd_bad(*pgd))) { 785 pgd_clear_bad(pgd); 786 return 1; 787 } 788 return 0; 789 } 790 791 static inline int p4d_none_or_clear_bad(p4d_t *p4d) 792 { 793 if (p4d_none(*p4d)) 794 return 1; 795 if (unlikely(p4d_bad(*p4d))) { 796 p4d_clear_bad(p4d); 797 return 1; 798 } 799 return 0; 800 } 801 802 static inline int pud_none_or_clear_bad(pud_t *pud) 803 { 804 if (pud_none(*pud)) 805 return 1; 806 if (unlikely(pud_bad(*pud))) { 807 pud_clear_bad(pud); 808 return 1; 809 } 810 return 0; 811 } 812 813 static inline int pmd_none_or_clear_bad(pmd_t *pmd) 814 { 815 if (pmd_none(*pmd)) 816 return 1; 817 if (unlikely(pmd_bad(*pmd))) { 818 pmd_clear_bad(pmd); 819 return 1; 820 } 821 return 0; 822 } 823 824 static inline pte_t __ptep_modify_prot_start(struct vm_area_struct *vma, 825 unsigned long addr, 826 pte_t *ptep) 827 { 828 /* 829 * Get the current pte state, but zero it out to make it 830 * non-present, preventing the hardware from asynchronously 831 * updating it. 832 */ 833 return ptep_get_and_clear(vma->vm_mm, addr, ptep); 834 } 835 836 static inline void __ptep_modify_prot_commit(struct vm_area_struct *vma, 837 unsigned long addr, 838 pte_t *ptep, pte_t pte) 839 { 840 /* 841 * The pte is non-present, so there's no hardware state to 842 * preserve. 843 */ 844 set_pte_at(vma->vm_mm, addr, ptep, pte); 845 } 846 847 #ifndef __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION 848 /* 849 * Start a pte protection read-modify-write transaction, which 850 * protects against asynchronous hardware modifications to the pte. 851 * The intention is not to prevent the hardware from making pte 852 * updates, but to prevent any updates it may make from being lost. 853 * 854 * This does not protect against other software modifications of the 855 * pte; the appropriate pte lock must be held over the transaction. 856 * 857 * Note that this interface is intended to be batchable, meaning that 858 * ptep_modify_prot_commit may not actually update the pte, but merely 859 * queue the update to be done at some later time. The update must be 860 * actually committed before the pte lock is released, however. 861 */ 862 static inline pte_t ptep_modify_prot_start(struct vm_area_struct *vma, 863 unsigned long addr, 864 pte_t *ptep) 865 { 866 return __ptep_modify_prot_start(vma, addr, ptep); 867 } 868 869 /* 870 * Commit an update to a pte, leaving any hardware-controlled bits in 871 * the PTE unmodified. 872 */ 873 static inline void ptep_modify_prot_commit(struct vm_area_struct *vma, 874 unsigned long addr, 875 pte_t *ptep, pte_t old_pte, pte_t pte) 876 { 877 __ptep_modify_prot_commit(vma, addr, ptep, pte); 878 } 879 #endif /* __HAVE_ARCH_PTEP_MODIFY_PROT_TRANSACTION */ 880 #endif /* CONFIG_MMU */ 881 882 /* 883 * No-op macros that just return the current protection value. Defined here 884 * because these macros can be used even if CONFIG_MMU is not defined. 885 */ 886 887 #ifndef pgprot_nx 888 #define pgprot_nx(prot) (prot) 889 #endif 890 891 #ifndef pgprot_noncached 892 #define pgprot_noncached(prot) (prot) 893 #endif 894 895 #ifndef pgprot_writecombine 896 #define pgprot_writecombine pgprot_noncached 897 #endif 898 899 #ifndef pgprot_writethrough 900 #define pgprot_writethrough pgprot_noncached 901 #endif 902 903 #ifndef pgprot_device 904 #define pgprot_device pgprot_noncached 905 #endif 906 907 #ifndef pgprot_mhp 908 #define pgprot_mhp(prot) (prot) 909 #endif 910 911 #ifdef CONFIG_MMU 912 #ifndef pgprot_modify 913 #define pgprot_modify pgprot_modify 914 static inline pgprot_t pgprot_modify(pgprot_t oldprot, pgprot_t newprot) 915 { 916 if (pgprot_val(oldprot) == pgprot_val(pgprot_noncached(oldprot))) 917 newprot = pgprot_noncached(newprot); 918 if (pgprot_val(oldprot) == pgprot_val(pgprot_writecombine(oldprot))) 919 newprot = pgprot_writecombine(newprot); 920 if (pgprot_val(oldprot) == pgprot_val(pgprot_device(oldprot))) 921 newprot = pgprot_device(newprot); 922 return newprot; 923 } 924 #endif 925 #endif /* CONFIG_MMU */ 926 927 #ifndef pgprot_encrypted 928 #define pgprot_encrypted(prot) (prot) 929 #endif 930 931 #ifndef pgprot_decrypted 932 #define pgprot_decrypted(prot) (prot) 933 #endif 934 935 /* 936 * A facility to provide lazy MMU batching. This allows PTE updates and 937 * page invalidations to be delayed until a call to leave lazy MMU mode 938 * is issued. Some architectures may benefit from doing this, and it is 939 * beneficial for both shadow and direct mode hypervisors, which may batch 940 * the PTE updates which happen during this window. Note that using this 941 * interface requires that read hazards be removed from the code. A read 942 * hazard could result in the direct mode hypervisor case, since the actual 943 * write to the page tables may not yet have taken place, so reads though 944 * a raw PTE pointer after it has been modified are not guaranteed to be 945 * up to date. This mode can only be entered and left under the protection of 946 * the page table locks for all page tables which may be modified. In the UP 947 * case, this is required so that preemption is disabled, and in the SMP case, 948 * it must synchronize the delayed page table writes properly on other CPUs. 949 */ 950 #ifndef __HAVE_ARCH_ENTER_LAZY_MMU_MODE 951 #define arch_enter_lazy_mmu_mode() do {} while (0) 952 #define arch_leave_lazy_mmu_mode() do {} while (0) 953 #define arch_flush_lazy_mmu_mode() do {} while (0) 954 #endif 955 956 /* 957 * A facility to provide batching of the reload of page tables and 958 * other process state with the actual context switch code for 959 * paravirtualized guests. By convention, only one of the batched 960 * update (lazy) modes (CPU, MMU) should be active at any given time, 961 * entry should never be nested, and entry and exits should always be 962 * paired. This is for sanity of maintaining and reasoning about the 963 * kernel code. In this case, the exit (end of the context switch) is 964 * in architecture-specific code, and so doesn't need a generic 965 * definition. 966 */ 967 #ifndef __HAVE_ARCH_START_CONTEXT_SWITCH 968 #define arch_start_context_switch(prev) do {} while (0) 969 #endif 970 971 #ifdef CONFIG_HAVE_ARCH_SOFT_DIRTY 972 #ifndef CONFIG_ARCH_ENABLE_THP_MIGRATION 973 static inline pmd_t pmd_swp_mksoft_dirty(pmd_t pmd) 974 { 975 return pmd; 976 } 977 978 static inline int pmd_swp_soft_dirty(pmd_t pmd) 979 { 980 return 0; 981 } 982 983 static inline pmd_t pmd_swp_clear_soft_dirty(pmd_t pmd) 984 { 985 return pmd; 986 } 987 #endif 988 #else /* !CONFIG_HAVE_ARCH_SOFT_DIRTY */ 989 static inline int pte_soft_dirty(pte_t pte) 990 { 991 return 0; 992 } 993 994 static inline int pmd_soft_dirty(pmd_t pmd) 995 { 996 return 0; 997 } 998 999 static inline pte_t pte_mksoft_dirty(pte_t pte) 1000 { 1001 return pte; 1002 } 1003 1004 static inline pmd_t pmd_mksoft_dirty(pmd_t pmd) 1005 { 1006 return pmd; 1007 } 1008 1009 static inline pte_t pte_clear_soft_dirty(pte_t pte) 1010 { 1011 return pte; 1012 } 1013 1014 static inline pmd_t pmd_clear_soft_dirty(pmd_t pmd) 1015 { 1016 return pmd; 1017 } 1018 1019 static inline pte_t pte_swp_mksoft_dirty(pte_t pte) 1020 { 1021 return pte; 1022 } 1023 1024 static inline int pte_swp_soft_dirty(pte_t pte) 1025 { 1026 return 0; 1027 } 1028 1029 static inline pte_t pte_swp_clear_soft_dirty(pte_t pte) 1030 { 1031 return pte; 1032 } 1033 1034 static inline pmd_t pmd_swp_mksoft_dirty(pmd_t pmd) 1035 { 1036 return pmd; 1037 } 1038 1039 static inline int pmd_swp_soft_dirty(pmd_t pmd) 1040 { 1041 return 0; 1042 } 1043 1044 static inline pmd_t pmd_swp_clear_soft_dirty(pmd_t pmd) 1045 { 1046 return pmd; 1047 } 1048 #endif 1049 1050 #ifndef __HAVE_PFNMAP_TRACKING 1051 /* 1052 * Interfaces that can be used by architecture code to keep track of 1053 * memory type of pfn mappings specified by the remap_pfn_range, 1054 * vmf_insert_pfn. 1055 */ 1056 1057 /* 1058 * track_pfn_remap is called when a _new_ pfn mapping is being established 1059 * by remap_pfn_range() for physical range indicated by pfn and size. 1060 */ 1061 static inline int track_pfn_remap(struct vm_area_struct *vma, pgprot_t *prot, 1062 unsigned long pfn, unsigned long addr, 1063 unsigned long size) 1064 { 1065 return 0; 1066 } 1067 1068 /* 1069 * track_pfn_insert is called when a _new_ single pfn is established 1070 * by vmf_insert_pfn(). 1071 */ 1072 static inline void track_pfn_insert(struct vm_area_struct *vma, pgprot_t *prot, 1073 pfn_t pfn) 1074 { 1075 } 1076 1077 /* 1078 * track_pfn_copy is called when vma that is covering the pfnmap gets 1079 * copied through copy_page_range(). 1080 */ 1081 static inline int track_pfn_copy(struct vm_area_struct *vma) 1082 { 1083 return 0; 1084 } 1085 1086 /* 1087 * untrack_pfn is called while unmapping a pfnmap for a region. 1088 * untrack can be called for a specific region indicated by pfn and size or 1089 * can be for the entire vma (in which case pfn, size are zero). 1090 */ 1091 static inline void untrack_pfn(struct vm_area_struct *vma, 1092 unsigned long pfn, unsigned long size) 1093 { 1094 } 1095 1096 /* 1097 * untrack_pfn_moved is called while mremapping a pfnmap for a new region. 1098 */ 1099 static inline void untrack_pfn_moved(struct vm_area_struct *vma) 1100 { 1101 } 1102 #else 1103 extern int track_pfn_remap(struct vm_area_struct *vma, pgprot_t *prot, 1104 unsigned long pfn, unsigned long addr, 1105 unsigned long size); 1106 extern void track_pfn_insert(struct vm_area_struct *vma, pgprot_t *prot, 1107 pfn_t pfn); 1108 extern int track_pfn_copy(struct vm_area_struct *vma); 1109 extern void untrack_pfn(struct vm_area_struct *vma, unsigned long pfn, 1110 unsigned long size); 1111 extern void untrack_pfn_moved(struct vm_area_struct *vma); 1112 #endif 1113 1114 #ifdef CONFIG_MMU 1115 #ifdef __HAVE_COLOR_ZERO_PAGE 1116 static inline int is_zero_pfn(unsigned long pfn) 1117 { 1118 extern unsigned long zero_pfn; 1119 unsigned long offset_from_zero_pfn = pfn - zero_pfn; 1120 return offset_from_zero_pfn <= (zero_page_mask >> PAGE_SHIFT); 1121 } 1122 1123 #define my_zero_pfn(addr) page_to_pfn(ZERO_PAGE(addr)) 1124 1125 #else 1126 static inline int is_zero_pfn(unsigned long pfn) 1127 { 1128 extern unsigned long zero_pfn; 1129 return pfn == zero_pfn; 1130 } 1131 1132 static inline unsigned long my_zero_pfn(unsigned long addr) 1133 { 1134 extern unsigned long zero_pfn; 1135 return zero_pfn; 1136 } 1137 #endif 1138 #else 1139 static inline int is_zero_pfn(unsigned long pfn) 1140 { 1141 return 0; 1142 } 1143 1144 static inline unsigned long my_zero_pfn(unsigned long addr) 1145 { 1146 return 0; 1147 } 1148 #endif /* CONFIG_MMU */ 1149 1150 #ifdef CONFIG_MMU 1151 1152 #ifndef CONFIG_TRANSPARENT_HUGEPAGE 1153 static inline int pmd_trans_huge(pmd_t pmd) 1154 { 1155 return 0; 1156 } 1157 #ifndef pmd_write 1158 static inline int pmd_write(pmd_t pmd) 1159 { 1160 BUG(); 1161 return 0; 1162 } 1163 #endif /* pmd_write */ 1164 #endif /* CONFIG_TRANSPARENT_HUGEPAGE */ 1165 1166 #ifndef pud_write 1167 static inline int pud_write(pud_t pud) 1168 { 1169 BUG(); 1170 return 0; 1171 } 1172 #endif /* pud_write */ 1173 1174 #if !defined(CONFIG_ARCH_HAS_PTE_DEVMAP) || !defined(CONFIG_TRANSPARENT_HUGEPAGE) 1175 static inline int pmd_devmap(pmd_t pmd) 1176 { 1177 return 0; 1178 } 1179 static inline int pud_devmap(pud_t pud) 1180 { 1181 return 0; 1182 } 1183 static inline int pgd_devmap(pgd_t pgd) 1184 { 1185 return 0; 1186 } 1187 #endif 1188 1189 #if !defined(CONFIG_TRANSPARENT_HUGEPAGE) || \ 1190 (defined(CONFIG_TRANSPARENT_HUGEPAGE) && \ 1191 !defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD)) 1192 static inline int pud_trans_huge(pud_t pud) 1193 { 1194 return 0; 1195 } 1196 #endif 1197 1198 /* See pmd_none_or_trans_huge_or_clear_bad for discussion. */ 1199 static inline int pud_none_or_trans_huge_or_dev_or_clear_bad(pud_t *pud) 1200 { 1201 pud_t pudval = READ_ONCE(*pud); 1202 1203 if (pud_none(pudval) || pud_trans_huge(pudval) || pud_devmap(pudval)) 1204 return 1; 1205 if (unlikely(pud_bad(pudval))) { 1206 pud_clear_bad(pud); 1207 return 1; 1208 } 1209 return 0; 1210 } 1211 1212 /* See pmd_trans_unstable for discussion. */ 1213 static inline int pud_trans_unstable(pud_t *pud) 1214 { 1215 #if defined(CONFIG_TRANSPARENT_HUGEPAGE) && \ 1216 defined(CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD) 1217 return pud_none_or_trans_huge_or_dev_or_clear_bad(pud); 1218 #else 1219 return 0; 1220 #endif 1221 } 1222 1223 #ifndef pmd_read_atomic 1224 static inline pmd_t pmd_read_atomic(pmd_t *pmdp) 1225 { 1226 /* 1227 * Depend on compiler for an atomic pmd read. NOTE: this is 1228 * only going to work, if the pmdval_t isn't larger than 1229 * an unsigned long. 1230 */ 1231 return *pmdp; 1232 } 1233 #endif 1234 1235 #ifndef arch_needs_pgtable_deposit 1236 #define arch_needs_pgtable_deposit() (false) 1237 #endif 1238 /* 1239 * This function is meant to be used by sites walking pagetables with 1240 * the mmap_lock held in read mode to protect against MADV_DONTNEED and 1241 * transhuge page faults. MADV_DONTNEED can convert a transhuge pmd 1242 * into a null pmd and the transhuge page fault can convert a null pmd 1243 * into an hugepmd or into a regular pmd (if the hugepage allocation 1244 * fails). While holding the mmap_lock in read mode the pmd becomes 1245 * stable and stops changing under us only if it's not null and not a 1246 * transhuge pmd. When those races occurs and this function makes a 1247 * difference vs the standard pmd_none_or_clear_bad, the result is 1248 * undefined so behaving like if the pmd was none is safe (because it 1249 * can return none anyway). The compiler level barrier() is critically 1250 * important to compute the two checks atomically on the same pmdval. 1251 * 1252 * For 32bit kernels with a 64bit large pmd_t this automatically takes 1253 * care of reading the pmd atomically to avoid SMP race conditions 1254 * against pmd_populate() when the mmap_lock is hold for reading by the 1255 * caller (a special atomic read not done by "gcc" as in the generic 1256 * version above, is also needed when THP is disabled because the page 1257 * fault can populate the pmd from under us). 1258 */ 1259 static inline int pmd_none_or_trans_huge_or_clear_bad(pmd_t *pmd) 1260 { 1261 pmd_t pmdval = pmd_read_atomic(pmd); 1262 /* 1263 * The barrier will stabilize the pmdval in a register or on 1264 * the stack so that it will stop changing under the code. 1265 * 1266 * When CONFIG_TRANSPARENT_HUGEPAGE=y on x86 32bit PAE, 1267 * pmd_read_atomic is allowed to return a not atomic pmdval 1268 * (for example pointing to an hugepage that has never been 1269 * mapped in the pmd). The below checks will only care about 1270 * the low part of the pmd with 32bit PAE x86 anyway, with the 1271 * exception of pmd_none(). So the important thing is that if 1272 * the low part of the pmd is found null, the high part will 1273 * be also null or the pmd_none() check below would be 1274 * confused. 1275 */ 1276 #ifdef CONFIG_TRANSPARENT_HUGEPAGE 1277 barrier(); 1278 #endif 1279 /* 1280 * !pmd_present() checks for pmd migration entries 1281 * 1282 * The complete check uses is_pmd_migration_entry() in linux/swapops.h 1283 * But using that requires moving current function and pmd_trans_unstable() 1284 * to linux/swapops.h to resolve dependency, which is too much code move. 1285 * 1286 * !pmd_present() is equivalent to is_pmd_migration_entry() currently, 1287 * because !pmd_present() pages can only be under migration not swapped 1288 * out. 1289 * 1290 * pmd_none() is preserved for future condition checks on pmd migration 1291 * entries and not confusing with this function name, although it is 1292 * redundant with !pmd_present(). 1293 */ 1294 if (pmd_none(pmdval) || pmd_trans_huge(pmdval) || 1295 (IS_ENABLED(CONFIG_ARCH_ENABLE_THP_MIGRATION) && !pmd_present(pmdval))) 1296 return 1; 1297 if (unlikely(pmd_bad(pmdval))) { 1298 pmd_clear_bad(pmd); 1299 return 1; 1300 } 1301 return 0; 1302 } 1303 1304 /* 1305 * This is a noop if Transparent Hugepage Support is not built into 1306 * the kernel. Otherwise it is equivalent to 1307 * pmd_none_or_trans_huge_or_clear_bad(), and shall only be called in 1308 * places that already verified the pmd is not none and they want to 1309 * walk ptes while holding the mmap sem in read mode (write mode don't 1310 * need this). If THP is not enabled, the pmd can't go away under the 1311 * code even if MADV_DONTNEED runs, but if THP is enabled we need to 1312 * run a pmd_trans_unstable before walking the ptes after 1313 * split_huge_pmd returns (because it may have run when the pmd become 1314 * null, but then a page fault can map in a THP and not a regular page). 1315 */ 1316 static inline int pmd_trans_unstable(pmd_t *pmd) 1317 { 1318 #ifdef CONFIG_TRANSPARENT_HUGEPAGE 1319 return pmd_none_or_trans_huge_or_clear_bad(pmd); 1320 #else 1321 return 0; 1322 #endif 1323 } 1324 1325 /* 1326 * the ordering of these checks is important for pmds with _page_devmap set. 1327 * if we check pmd_trans_unstable() first we will trip the bad_pmd() check 1328 * inside of pmd_none_or_trans_huge_or_clear_bad(). this will end up correctly 1329 * returning 1 but not before it spams dmesg with the pmd_clear_bad() output. 1330 */ 1331 static inline int pmd_devmap_trans_unstable(pmd_t *pmd) 1332 { 1333 return pmd_devmap(*pmd) || pmd_trans_unstable(pmd); 1334 } 1335 1336 #ifndef CONFIG_NUMA_BALANCING 1337 /* 1338 * Technically a PTE can be PROTNONE even when not doing NUMA balancing but 1339 * the only case the kernel cares is for NUMA balancing and is only ever set 1340 * when the VMA is accessible. For PROT_NONE VMAs, the PTEs are not marked 1341 * _PAGE_PROTNONE so by default, implement the helper as "always no". It 1342 * is the responsibility of the caller to distinguish between PROT_NONE 1343 * protections and NUMA hinting fault protections. 1344 */ 1345 static inline int pte_protnone(pte_t pte) 1346 { 1347 return 0; 1348 } 1349 1350 static inline int pmd_protnone(pmd_t pmd) 1351 { 1352 return 0; 1353 } 1354 #endif /* CONFIG_NUMA_BALANCING */ 1355 1356 #endif /* CONFIG_MMU */ 1357 1358 #ifdef CONFIG_HAVE_ARCH_HUGE_VMAP 1359 1360 #ifndef __PAGETABLE_P4D_FOLDED 1361 int p4d_set_huge(p4d_t *p4d, phys_addr_t addr, pgprot_t prot); 1362 int p4d_clear_huge(p4d_t *p4d); 1363 #else 1364 static inline int p4d_set_huge(p4d_t *p4d, phys_addr_t addr, pgprot_t prot) 1365 { 1366 return 0; 1367 } 1368 static inline int p4d_clear_huge(p4d_t *p4d) 1369 { 1370 return 0; 1371 } 1372 #endif /* !__PAGETABLE_P4D_FOLDED */ 1373 1374 int pud_set_huge(pud_t *pud, phys_addr_t addr, pgprot_t prot); 1375 int pmd_set_huge(pmd_t *pmd, phys_addr_t addr, pgprot_t prot); 1376 int pud_clear_huge(pud_t *pud); 1377 int pmd_clear_huge(pmd_t *pmd); 1378 int p4d_free_pud_page(p4d_t *p4d, unsigned long addr); 1379 int pud_free_pmd_page(pud_t *pud, unsigned long addr); 1380 int pmd_free_pte_page(pmd_t *pmd, unsigned long addr); 1381 #else /* !CONFIG_HAVE_ARCH_HUGE_VMAP */ 1382 static inline int p4d_set_huge(p4d_t *p4d, phys_addr_t addr, pgprot_t prot) 1383 { 1384 return 0; 1385 } 1386 static inline int pud_set_huge(pud_t *pud, phys_addr_t addr, pgprot_t prot) 1387 { 1388 return 0; 1389 } 1390 static inline int pmd_set_huge(pmd_t *pmd, phys_addr_t addr, pgprot_t prot) 1391 { 1392 return 0; 1393 } 1394 static inline int p4d_clear_huge(p4d_t *p4d) 1395 { 1396 return 0; 1397 } 1398 static inline int pud_clear_huge(pud_t *pud) 1399 { 1400 return 0; 1401 } 1402 static inline int pmd_clear_huge(pmd_t *pmd) 1403 { 1404 return 0; 1405 } 1406 static inline int p4d_free_pud_page(p4d_t *p4d, unsigned long addr) 1407 { 1408 return 0; 1409 } 1410 static inline int pud_free_pmd_page(pud_t *pud, unsigned long addr) 1411 { 1412 return 0; 1413 } 1414 static inline int pmd_free_pte_page(pmd_t *pmd, unsigned long addr) 1415 { 1416 return 0; 1417 } 1418 #endif /* CONFIG_HAVE_ARCH_HUGE_VMAP */ 1419 1420 #ifndef __HAVE_ARCH_FLUSH_PMD_TLB_RANGE 1421 #ifdef CONFIG_TRANSPARENT_HUGEPAGE 1422 /* 1423 * ARCHes with special requirements for evicting THP backing TLB entries can 1424 * implement this. Otherwise also, it can help optimize normal TLB flush in 1425 * THP regime. Stock flush_tlb_range() typically has optimization to nuke the 1426 * entire TLB if flush span is greater than a threshold, which will 1427 * likely be true for a single huge page. Thus a single THP flush will 1428 * invalidate the entire TLB which is not desirable. 1429 * e.g. see arch/arc: flush_pmd_tlb_range 1430 */ 1431 #define flush_pmd_tlb_range(vma, addr, end) flush_tlb_range(vma, addr, end) 1432 #define flush_pud_tlb_range(vma, addr, end) flush_tlb_range(vma, addr, end) 1433 #else 1434 #define flush_pmd_tlb_range(vma, addr, end) BUILD_BUG() 1435 #define flush_pud_tlb_range(vma, addr, end) BUILD_BUG() 1436 #endif 1437 #endif 1438 1439 struct file; 1440 int phys_mem_access_prot_allowed(struct file *file, unsigned long pfn, 1441 unsigned long size, pgprot_t *vma_prot); 1442 1443 #ifndef CONFIG_X86_ESPFIX64 1444 static inline void init_espfix_bsp(void) { } 1445 #endif 1446 1447 extern void __init pgtable_cache_init(void); 1448 1449 #ifndef __HAVE_ARCH_PFN_MODIFY_ALLOWED 1450 static inline bool pfn_modify_allowed(unsigned long pfn, pgprot_t prot) 1451 { 1452 return true; 1453 } 1454 1455 static inline bool arch_has_pfn_modify_check(void) 1456 { 1457 return false; 1458 } 1459 #endif /* !_HAVE_ARCH_PFN_MODIFY_ALLOWED */ 1460 1461 /* 1462 * Architecture PAGE_KERNEL_* fallbacks 1463 * 1464 * Some architectures don't define certain PAGE_KERNEL_* flags. This is either 1465 * because they really don't support them, or the port needs to be updated to 1466 * reflect the required functionality. Below are a set of relatively safe 1467 * fallbacks, as best effort, which we can count on in lieu of the architectures 1468 * not defining them on their own yet. 1469 */ 1470 1471 #ifndef PAGE_KERNEL_RO 1472 # define PAGE_KERNEL_RO PAGE_KERNEL 1473 #endif 1474 1475 #ifndef PAGE_KERNEL_EXEC 1476 # define PAGE_KERNEL_EXEC PAGE_KERNEL 1477 #endif 1478 1479 /* 1480 * Page Table Modification bits for pgtbl_mod_mask. 1481 * 1482 * These are used by the p?d_alloc_track*() set of functions an in the generic 1483 * vmalloc/ioremap code to track at which page-table levels entries have been 1484 * modified. Based on that the code can better decide when vmalloc and ioremap 1485 * mapping changes need to be synchronized to other page-tables in the system. 1486 */ 1487 #define __PGTBL_PGD_MODIFIED 0 1488 #define __PGTBL_P4D_MODIFIED 1 1489 #define __PGTBL_PUD_MODIFIED 2 1490 #define __PGTBL_PMD_MODIFIED 3 1491 #define __PGTBL_PTE_MODIFIED 4 1492 1493 #define PGTBL_PGD_MODIFIED BIT(__PGTBL_PGD_MODIFIED) 1494 #define PGTBL_P4D_MODIFIED BIT(__PGTBL_P4D_MODIFIED) 1495 #define PGTBL_PUD_MODIFIED BIT(__PGTBL_PUD_MODIFIED) 1496 #define PGTBL_PMD_MODIFIED BIT(__PGTBL_PMD_MODIFIED) 1497 #define PGTBL_PTE_MODIFIED BIT(__PGTBL_PTE_MODIFIED) 1498 1499 /* Page-Table Modification Mask */ 1500 typedef unsigned int pgtbl_mod_mask; 1501 1502 #endif /* !__ASSEMBLY__ */ 1503 1504 #if !defined(MAX_POSSIBLE_PHYSMEM_BITS) && !defined(CONFIG_64BIT) 1505 #ifdef CONFIG_PHYS_ADDR_T_64BIT 1506 /* 1507 * ZSMALLOC needs to know the highest PFN on 32-bit architectures 1508 * with physical address space extension, but falls back to 1509 * BITS_PER_LONG otherwise. 1510 */ 1511 #error Missing MAX_POSSIBLE_PHYSMEM_BITS definition 1512 #else 1513 #define MAX_POSSIBLE_PHYSMEM_BITS 32 1514 #endif 1515 #endif 1516 1517 #ifndef has_transparent_hugepage 1518 #ifdef CONFIG_TRANSPARENT_HUGEPAGE 1519 #define has_transparent_hugepage() 1 1520 #else 1521 #define has_transparent_hugepage() 0 1522 #endif 1523 #endif 1524 1525 /* 1526 * On some architectures it depends on the mm if the p4d/pud or pmd 1527 * layer of the page table hierarchy is folded or not. 1528 */ 1529 #ifndef mm_p4d_folded 1530 #define mm_p4d_folded(mm) __is_defined(__PAGETABLE_P4D_FOLDED) 1531 #endif 1532 1533 #ifndef mm_pud_folded 1534 #define mm_pud_folded(mm) __is_defined(__PAGETABLE_PUD_FOLDED) 1535 #endif 1536 1537 #ifndef mm_pmd_folded 1538 #define mm_pmd_folded(mm) __is_defined(__PAGETABLE_PMD_FOLDED) 1539 #endif 1540 1541 #ifndef p4d_offset_lockless 1542 #define p4d_offset_lockless(pgdp, pgd, address) p4d_offset(&(pgd), address) 1543 #endif 1544 #ifndef pud_offset_lockless 1545 #define pud_offset_lockless(p4dp, p4d, address) pud_offset(&(p4d), address) 1546 #endif 1547 #ifndef pmd_offset_lockless 1548 #define pmd_offset_lockless(pudp, pud, address) pmd_offset(&(pud), address) 1549 #endif 1550 1551 /* 1552 * p?d_leaf() - true if this entry is a final mapping to a physical address. 1553 * This differs from p?d_huge() by the fact that they are always available (if 1554 * the architecture supports large pages at the appropriate level) even 1555 * if CONFIG_HUGETLB_PAGE is not defined. 1556 * Only meaningful when called on a valid entry. 1557 */ 1558 #ifndef pgd_leaf 1559 #define pgd_leaf(x) 0 1560 #endif 1561 #ifndef p4d_leaf 1562 #define p4d_leaf(x) 0 1563 #endif 1564 #ifndef pud_leaf 1565 #define pud_leaf(x) 0 1566 #endif 1567 #ifndef pmd_leaf 1568 #define pmd_leaf(x) 0 1569 #endif 1570 1571 #ifndef pgd_leaf_size 1572 #define pgd_leaf_size(x) (1ULL << PGDIR_SHIFT) 1573 #endif 1574 #ifndef p4d_leaf_size 1575 #define p4d_leaf_size(x) P4D_SIZE 1576 #endif 1577 #ifndef pud_leaf_size 1578 #define pud_leaf_size(x) PUD_SIZE 1579 #endif 1580 #ifndef pmd_leaf_size 1581 #define pmd_leaf_size(x) PMD_SIZE 1582 #endif 1583 #ifndef pte_leaf_size 1584 #define pte_leaf_size(x) PAGE_SIZE 1585 #endif 1586 1587 #endif /* _LINUX_PGTABLE_H */ 1588