1 /* 2 * PPC Huge TLB Page Support for Kernel. 3 * 4 * Copyright (C) 2003 David Gibson, IBM Corporation. 5 * Copyright (C) 2011 Becky Bruce, Freescale Semiconductor 6 * 7 * Based on the IA-32 version: 8 * Copyright (C) 2002, Rohit Seth <rohit.seth@intel.com> 9 */ 10 11 #include <linux/mm.h> 12 #include <linux/io.h> 13 #include <linux/slab.h> 14 #include <linux/hugetlb.h> 15 #include <linux/export.h> 16 #include <linux/of_fdt.h> 17 #include <linux/memblock.h> 18 #include <linux/bootmem.h> 19 #include <linux/moduleparam.h> 20 #include <asm/pgtable.h> 21 #include <asm/pgalloc.h> 22 #include <asm/tlb.h> 23 #include <asm/setup.h> 24 #include <asm/hugetlb.h> 25 26 #ifdef CONFIG_HUGETLB_PAGE 27 28 #define PAGE_SHIFT_64K 16 29 #define PAGE_SHIFT_16M 24 30 #define PAGE_SHIFT_16G 34 31 32 unsigned int HPAGE_SHIFT; 33 34 /* 35 * Tracks gpages after the device tree is scanned and before the 36 * huge_boot_pages list is ready. On non-Freescale implementations, this is 37 * just used to track 16G pages and so is a single array. FSL-based 38 * implementations may have more than one gpage size, so we need multiple 39 * arrays 40 */ 41 #ifdef CONFIG_PPC_FSL_BOOK3E 42 #define MAX_NUMBER_GPAGES 128 43 struct psize_gpages { 44 u64 gpage_list[MAX_NUMBER_GPAGES]; 45 unsigned int nr_gpages; 46 }; 47 static struct psize_gpages gpage_freearray[MMU_PAGE_COUNT]; 48 #else 49 #define MAX_NUMBER_GPAGES 1024 50 static u64 gpage_freearray[MAX_NUMBER_GPAGES]; 51 static unsigned nr_gpages; 52 #endif 53 54 #define hugepd_none(hpd) ((hpd).pd == 0) 55 56 #ifdef CONFIG_PPC_BOOK3S_64 57 /* 58 * At this point we do the placement change only for BOOK3S 64. This would 59 * possibly work on other subarchs. 60 */ 61 62 /* 63 * We have PGD_INDEX_SIZ = 12 and PTE_INDEX_SIZE = 8, so that we can have 64 * 16GB hugepage pte in PGD and 16MB hugepage pte at PMD; 65 */ 66 int pmd_huge(pmd_t pmd) 67 { 68 /* 69 * leaf pte for huge page, bottom two bits != 00 70 */ 71 return ((pmd_val(pmd) & 0x3) != 0x0); 72 } 73 74 int pud_huge(pud_t pud) 75 { 76 /* 77 * leaf pte for huge page, bottom two bits != 00 78 */ 79 return ((pud_val(pud) & 0x3) != 0x0); 80 } 81 82 int pgd_huge(pgd_t pgd) 83 { 84 /* 85 * leaf pte for huge page, bottom two bits != 00 86 */ 87 return ((pgd_val(pgd) & 0x3) != 0x0); 88 } 89 90 int pmd_huge_support(void) 91 { 92 return 1; 93 } 94 #else 95 int pmd_huge(pmd_t pmd) 96 { 97 return 0; 98 } 99 100 int pud_huge(pud_t pud) 101 { 102 return 0; 103 } 104 105 int pgd_huge(pgd_t pgd) 106 { 107 return 0; 108 } 109 110 int pmd_huge_support(void) 111 { 112 return 0; 113 } 114 #endif 115 116 pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr) 117 { 118 /* Only called for hugetlbfs pages, hence can ignore THP */ 119 return find_linux_pte_or_hugepte(mm->pgd, addr, NULL); 120 } 121 122 static int __hugepte_alloc(struct mm_struct *mm, hugepd_t *hpdp, 123 unsigned long address, unsigned pdshift, unsigned pshift) 124 { 125 struct kmem_cache *cachep; 126 pte_t *new; 127 128 #ifdef CONFIG_PPC_FSL_BOOK3E 129 int i; 130 int num_hugepd = 1 << (pshift - pdshift); 131 cachep = hugepte_cache; 132 #else 133 cachep = PGT_CACHE(pdshift - pshift); 134 #endif 135 136 new = kmem_cache_zalloc(cachep, GFP_KERNEL|__GFP_REPEAT); 137 138 BUG_ON(pshift > HUGEPD_SHIFT_MASK); 139 BUG_ON((unsigned long)new & HUGEPD_SHIFT_MASK); 140 141 if (! new) 142 return -ENOMEM; 143 144 spin_lock(&mm->page_table_lock); 145 #ifdef CONFIG_PPC_FSL_BOOK3E 146 /* 147 * We have multiple higher-level entries that point to the same 148 * actual pte location. Fill in each as we go and backtrack on error. 149 * We need all of these so the DTLB pgtable walk code can find the 150 * right higher-level entry without knowing if it's a hugepage or not. 151 */ 152 for (i = 0; i < num_hugepd; i++, hpdp++) { 153 if (unlikely(!hugepd_none(*hpdp))) 154 break; 155 else 156 /* We use the old format for PPC_FSL_BOOK3E */ 157 hpdp->pd = ((unsigned long)new & ~PD_HUGE) | pshift; 158 } 159 /* If we bailed from the for loop early, an error occurred, clean up */ 160 if (i < num_hugepd) { 161 for (i = i - 1 ; i >= 0; i--, hpdp--) 162 hpdp->pd = 0; 163 kmem_cache_free(cachep, new); 164 } 165 #else 166 if (!hugepd_none(*hpdp)) 167 kmem_cache_free(cachep, new); 168 else { 169 #ifdef CONFIG_PPC_BOOK3S_64 170 hpdp->pd = (unsigned long)new | 171 (shift_to_mmu_psize(pshift) << 2); 172 #else 173 hpdp->pd = ((unsigned long)new & ~PD_HUGE) | pshift; 174 #endif 175 } 176 #endif 177 spin_unlock(&mm->page_table_lock); 178 return 0; 179 } 180 181 /* 182 * These macros define how to determine which level of the page table holds 183 * the hpdp. 184 */ 185 #ifdef CONFIG_PPC_FSL_BOOK3E 186 #define HUGEPD_PGD_SHIFT PGDIR_SHIFT 187 #define HUGEPD_PUD_SHIFT PUD_SHIFT 188 #else 189 #define HUGEPD_PGD_SHIFT PUD_SHIFT 190 #define HUGEPD_PUD_SHIFT PMD_SHIFT 191 #endif 192 193 #ifdef CONFIG_PPC_BOOK3S_64 194 /* 195 * At this point we do the placement change only for BOOK3S 64. This would 196 * possibly work on other subarchs. 197 */ 198 pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned long sz) 199 { 200 pgd_t *pg; 201 pud_t *pu; 202 pmd_t *pm; 203 hugepd_t *hpdp = NULL; 204 unsigned pshift = __ffs(sz); 205 unsigned pdshift = PGDIR_SHIFT; 206 207 addr &= ~(sz-1); 208 pg = pgd_offset(mm, addr); 209 210 if (pshift == PGDIR_SHIFT) 211 /* 16GB huge page */ 212 return (pte_t *) pg; 213 else if (pshift > PUD_SHIFT) 214 /* 215 * We need to use hugepd table 216 */ 217 hpdp = (hugepd_t *)pg; 218 else { 219 pdshift = PUD_SHIFT; 220 pu = pud_alloc(mm, pg, addr); 221 if (pshift == PUD_SHIFT) 222 return (pte_t *)pu; 223 else if (pshift > PMD_SHIFT) 224 hpdp = (hugepd_t *)pu; 225 else { 226 pdshift = PMD_SHIFT; 227 pm = pmd_alloc(mm, pu, addr); 228 if (pshift == PMD_SHIFT) 229 /* 16MB hugepage */ 230 return (pte_t *)pm; 231 else 232 hpdp = (hugepd_t *)pm; 233 } 234 } 235 if (!hpdp) 236 return NULL; 237 238 BUG_ON(!hugepd_none(*hpdp) && !hugepd_ok(*hpdp)); 239 240 if (hugepd_none(*hpdp) && __hugepte_alloc(mm, hpdp, addr, pdshift, pshift)) 241 return NULL; 242 243 return hugepte_offset(hpdp, addr, pdshift); 244 } 245 246 #else 247 248 pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned long sz) 249 { 250 pgd_t *pg; 251 pud_t *pu; 252 pmd_t *pm; 253 hugepd_t *hpdp = NULL; 254 unsigned pshift = __ffs(sz); 255 unsigned pdshift = PGDIR_SHIFT; 256 257 addr &= ~(sz-1); 258 259 pg = pgd_offset(mm, addr); 260 261 if (pshift >= HUGEPD_PGD_SHIFT) { 262 hpdp = (hugepd_t *)pg; 263 } else { 264 pdshift = PUD_SHIFT; 265 pu = pud_alloc(mm, pg, addr); 266 if (pshift >= HUGEPD_PUD_SHIFT) { 267 hpdp = (hugepd_t *)pu; 268 } else { 269 pdshift = PMD_SHIFT; 270 pm = pmd_alloc(mm, pu, addr); 271 hpdp = (hugepd_t *)pm; 272 } 273 } 274 275 if (!hpdp) 276 return NULL; 277 278 BUG_ON(!hugepd_none(*hpdp) && !hugepd_ok(*hpdp)); 279 280 if (hugepd_none(*hpdp) && __hugepte_alloc(mm, hpdp, addr, pdshift, pshift)) 281 return NULL; 282 283 return hugepte_offset(hpdp, addr, pdshift); 284 } 285 #endif 286 287 #ifdef CONFIG_PPC_FSL_BOOK3E 288 /* Build list of addresses of gigantic pages. This function is used in early 289 * boot before the buddy or bootmem allocator is setup. 290 */ 291 void add_gpage(u64 addr, u64 page_size, unsigned long number_of_pages) 292 { 293 unsigned int idx = shift_to_mmu_psize(__ffs(page_size)); 294 int i; 295 296 if (addr == 0) 297 return; 298 299 gpage_freearray[idx].nr_gpages = number_of_pages; 300 301 for (i = 0; i < number_of_pages; i++) { 302 gpage_freearray[idx].gpage_list[i] = addr; 303 addr += page_size; 304 } 305 } 306 307 /* 308 * Moves the gigantic page addresses from the temporary list to the 309 * huge_boot_pages list. 310 */ 311 int alloc_bootmem_huge_page(struct hstate *hstate) 312 { 313 struct huge_bootmem_page *m; 314 int idx = shift_to_mmu_psize(huge_page_shift(hstate)); 315 int nr_gpages = gpage_freearray[idx].nr_gpages; 316 317 if (nr_gpages == 0) 318 return 0; 319 320 #ifdef CONFIG_HIGHMEM 321 /* 322 * If gpages can be in highmem we can't use the trick of storing the 323 * data structure in the page; allocate space for this 324 */ 325 m = alloc_bootmem(sizeof(struct huge_bootmem_page)); 326 m->phys = gpage_freearray[idx].gpage_list[--nr_gpages]; 327 #else 328 m = phys_to_virt(gpage_freearray[idx].gpage_list[--nr_gpages]); 329 #endif 330 331 list_add(&m->list, &huge_boot_pages); 332 gpage_freearray[idx].nr_gpages = nr_gpages; 333 gpage_freearray[idx].gpage_list[nr_gpages] = 0; 334 m->hstate = hstate; 335 336 return 1; 337 } 338 /* 339 * Scan the command line hugepagesz= options for gigantic pages; store those in 340 * a list that we use to allocate the memory once all options are parsed. 341 */ 342 343 unsigned long gpage_npages[MMU_PAGE_COUNT]; 344 345 static int __init do_gpage_early_setup(char *param, char *val, 346 const char *unused) 347 { 348 static phys_addr_t size; 349 unsigned long npages; 350 351 /* 352 * The hugepagesz and hugepages cmdline options are interleaved. We 353 * use the size variable to keep track of whether or not this was done 354 * properly and skip over instances where it is incorrect. Other 355 * command-line parsing code will issue warnings, so we don't need to. 356 * 357 */ 358 if ((strcmp(param, "default_hugepagesz") == 0) || 359 (strcmp(param, "hugepagesz") == 0)) { 360 size = memparse(val, NULL); 361 } else if (strcmp(param, "hugepages") == 0) { 362 if (size != 0) { 363 if (sscanf(val, "%lu", &npages) <= 0) 364 npages = 0; 365 gpage_npages[shift_to_mmu_psize(__ffs(size))] = npages; 366 size = 0; 367 } 368 } 369 return 0; 370 } 371 372 373 /* 374 * This function allocates physical space for pages that are larger than the 375 * buddy allocator can handle. We want to allocate these in highmem because 376 * the amount of lowmem is limited. This means that this function MUST be 377 * called before lowmem_end_addr is set up in MMU_init() in order for the lmb 378 * allocate to grab highmem. 379 */ 380 void __init reserve_hugetlb_gpages(void) 381 { 382 static __initdata char cmdline[COMMAND_LINE_SIZE]; 383 phys_addr_t size, base; 384 int i; 385 386 strlcpy(cmdline, boot_command_line, COMMAND_LINE_SIZE); 387 parse_args("hugetlb gpages", cmdline, NULL, 0, 0, 0, 388 &do_gpage_early_setup); 389 390 /* 391 * Walk gpage list in reverse, allocating larger page sizes first. 392 * Skip over unsupported sizes, or sizes that have 0 gpages allocated. 393 * When we reach the point in the list where pages are no longer 394 * considered gpages, we're done. 395 */ 396 for (i = MMU_PAGE_COUNT-1; i >= 0; i--) { 397 if (mmu_psize_defs[i].shift == 0 || gpage_npages[i] == 0) 398 continue; 399 else if (mmu_psize_to_shift(i) < (MAX_ORDER + PAGE_SHIFT)) 400 break; 401 402 size = (phys_addr_t)(1ULL << mmu_psize_to_shift(i)); 403 base = memblock_alloc_base(size * gpage_npages[i], size, 404 MEMBLOCK_ALLOC_ANYWHERE); 405 add_gpage(base, size, gpage_npages[i]); 406 } 407 } 408 409 #else /* !PPC_FSL_BOOK3E */ 410 411 /* Build list of addresses of gigantic pages. This function is used in early 412 * boot before the buddy or bootmem allocator is setup. 413 */ 414 void add_gpage(u64 addr, u64 page_size, unsigned long number_of_pages) 415 { 416 if (!addr) 417 return; 418 while (number_of_pages > 0) { 419 gpage_freearray[nr_gpages] = addr; 420 nr_gpages++; 421 number_of_pages--; 422 addr += page_size; 423 } 424 } 425 426 /* Moves the gigantic page addresses from the temporary list to the 427 * huge_boot_pages list. 428 */ 429 int alloc_bootmem_huge_page(struct hstate *hstate) 430 { 431 struct huge_bootmem_page *m; 432 if (nr_gpages == 0) 433 return 0; 434 m = phys_to_virt(gpage_freearray[--nr_gpages]); 435 gpage_freearray[nr_gpages] = 0; 436 list_add(&m->list, &huge_boot_pages); 437 m->hstate = hstate; 438 return 1; 439 } 440 #endif 441 442 int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep) 443 { 444 return 0; 445 } 446 447 #ifdef CONFIG_PPC_FSL_BOOK3E 448 #define HUGEPD_FREELIST_SIZE \ 449 ((PAGE_SIZE - sizeof(struct hugepd_freelist)) / sizeof(pte_t)) 450 451 struct hugepd_freelist { 452 struct rcu_head rcu; 453 unsigned int index; 454 void *ptes[0]; 455 }; 456 457 static DEFINE_PER_CPU(struct hugepd_freelist *, hugepd_freelist_cur); 458 459 static void hugepd_free_rcu_callback(struct rcu_head *head) 460 { 461 struct hugepd_freelist *batch = 462 container_of(head, struct hugepd_freelist, rcu); 463 unsigned int i; 464 465 for (i = 0; i < batch->index; i++) 466 kmem_cache_free(hugepte_cache, batch->ptes[i]); 467 468 free_page((unsigned long)batch); 469 } 470 471 static void hugepd_free(struct mmu_gather *tlb, void *hugepte) 472 { 473 struct hugepd_freelist **batchp; 474 475 batchp = &get_cpu_var(hugepd_freelist_cur); 476 477 if (atomic_read(&tlb->mm->mm_users) < 2 || 478 cpumask_equal(mm_cpumask(tlb->mm), 479 cpumask_of(smp_processor_id()))) { 480 kmem_cache_free(hugepte_cache, hugepte); 481 put_cpu_var(hugepd_freelist_cur); 482 return; 483 } 484 485 if (*batchp == NULL) { 486 *batchp = (struct hugepd_freelist *)__get_free_page(GFP_ATOMIC); 487 (*batchp)->index = 0; 488 } 489 490 (*batchp)->ptes[(*batchp)->index++] = hugepte; 491 if ((*batchp)->index == HUGEPD_FREELIST_SIZE) { 492 call_rcu_sched(&(*batchp)->rcu, hugepd_free_rcu_callback); 493 *batchp = NULL; 494 } 495 put_cpu_var(hugepd_freelist_cur); 496 } 497 #endif 498 499 static void free_hugepd_range(struct mmu_gather *tlb, hugepd_t *hpdp, int pdshift, 500 unsigned long start, unsigned long end, 501 unsigned long floor, unsigned long ceiling) 502 { 503 pte_t *hugepte = hugepd_page(*hpdp); 504 int i; 505 506 unsigned long pdmask = ~((1UL << pdshift) - 1); 507 unsigned int num_hugepd = 1; 508 509 #ifdef CONFIG_PPC_FSL_BOOK3E 510 /* Note: On fsl the hpdp may be the first of several */ 511 num_hugepd = (1 << (hugepd_shift(*hpdp) - pdshift)); 512 #else 513 unsigned int shift = hugepd_shift(*hpdp); 514 #endif 515 516 start &= pdmask; 517 if (start < floor) 518 return; 519 if (ceiling) { 520 ceiling &= pdmask; 521 if (! ceiling) 522 return; 523 } 524 if (end - 1 > ceiling - 1) 525 return; 526 527 for (i = 0; i < num_hugepd; i++, hpdp++) 528 hpdp->pd = 0; 529 530 tlb->need_flush = 1; 531 532 #ifdef CONFIG_PPC_FSL_BOOK3E 533 hugepd_free(tlb, hugepte); 534 #else 535 pgtable_free_tlb(tlb, hugepte, pdshift - shift); 536 #endif 537 } 538 539 static void hugetlb_free_pmd_range(struct mmu_gather *tlb, pud_t *pud, 540 unsigned long addr, unsigned long end, 541 unsigned long floor, unsigned long ceiling) 542 { 543 pmd_t *pmd; 544 unsigned long next; 545 unsigned long start; 546 547 start = addr; 548 do { 549 pmd = pmd_offset(pud, addr); 550 next = pmd_addr_end(addr, end); 551 if (!is_hugepd(pmd)) { 552 /* 553 * if it is not hugepd pointer, we should already find 554 * it cleared. 555 */ 556 WARN_ON(!pmd_none_or_clear_bad(pmd)); 557 continue; 558 } 559 #ifdef CONFIG_PPC_FSL_BOOK3E 560 /* 561 * Increment next by the size of the huge mapping since 562 * there may be more than one entry at this level for a 563 * single hugepage, but all of them point to 564 * the same kmem cache that holds the hugepte. 565 */ 566 next = addr + (1 << hugepd_shift(*(hugepd_t *)pmd)); 567 #endif 568 free_hugepd_range(tlb, (hugepd_t *)pmd, PMD_SHIFT, 569 addr, next, floor, ceiling); 570 } while (addr = next, addr != end); 571 572 start &= PUD_MASK; 573 if (start < floor) 574 return; 575 if (ceiling) { 576 ceiling &= PUD_MASK; 577 if (!ceiling) 578 return; 579 } 580 if (end - 1 > ceiling - 1) 581 return; 582 583 pmd = pmd_offset(pud, start); 584 pud_clear(pud); 585 pmd_free_tlb(tlb, pmd, start); 586 } 587 588 static void hugetlb_free_pud_range(struct mmu_gather *tlb, pgd_t *pgd, 589 unsigned long addr, unsigned long end, 590 unsigned long floor, unsigned long ceiling) 591 { 592 pud_t *pud; 593 unsigned long next; 594 unsigned long start; 595 596 start = addr; 597 do { 598 pud = pud_offset(pgd, addr); 599 next = pud_addr_end(addr, end); 600 if (!is_hugepd(pud)) { 601 if (pud_none_or_clear_bad(pud)) 602 continue; 603 hugetlb_free_pmd_range(tlb, pud, addr, next, floor, 604 ceiling); 605 } else { 606 #ifdef CONFIG_PPC_FSL_BOOK3E 607 /* 608 * Increment next by the size of the huge mapping since 609 * there may be more than one entry at this level for a 610 * single hugepage, but all of them point to 611 * the same kmem cache that holds the hugepte. 612 */ 613 next = addr + (1 << hugepd_shift(*(hugepd_t *)pud)); 614 #endif 615 free_hugepd_range(tlb, (hugepd_t *)pud, PUD_SHIFT, 616 addr, next, floor, ceiling); 617 } 618 } while (addr = next, addr != end); 619 620 start &= PGDIR_MASK; 621 if (start < floor) 622 return; 623 if (ceiling) { 624 ceiling &= PGDIR_MASK; 625 if (!ceiling) 626 return; 627 } 628 if (end - 1 > ceiling - 1) 629 return; 630 631 pud = pud_offset(pgd, start); 632 pgd_clear(pgd); 633 pud_free_tlb(tlb, pud, start); 634 } 635 636 /* 637 * This function frees user-level page tables of a process. 638 */ 639 void hugetlb_free_pgd_range(struct mmu_gather *tlb, 640 unsigned long addr, unsigned long end, 641 unsigned long floor, unsigned long ceiling) 642 { 643 pgd_t *pgd; 644 unsigned long next; 645 646 /* 647 * Because there are a number of different possible pagetable 648 * layouts for hugepage ranges, we limit knowledge of how 649 * things should be laid out to the allocation path 650 * (huge_pte_alloc(), above). Everything else works out the 651 * structure as it goes from information in the hugepd 652 * pointers. That means that we can't here use the 653 * optimization used in the normal page free_pgd_range(), of 654 * checking whether we're actually covering a large enough 655 * range to have to do anything at the top level of the walk 656 * instead of at the bottom. 657 * 658 * To make sense of this, you should probably go read the big 659 * block comment at the top of the normal free_pgd_range(), 660 * too. 661 */ 662 663 do { 664 next = pgd_addr_end(addr, end); 665 pgd = pgd_offset(tlb->mm, addr); 666 if (!is_hugepd(pgd)) { 667 if (pgd_none_or_clear_bad(pgd)) 668 continue; 669 hugetlb_free_pud_range(tlb, pgd, addr, next, floor, ceiling); 670 } else { 671 #ifdef CONFIG_PPC_FSL_BOOK3E 672 /* 673 * Increment next by the size of the huge mapping since 674 * there may be more than one entry at the pgd level 675 * for a single hugepage, but all of them point to the 676 * same kmem cache that holds the hugepte. 677 */ 678 next = addr + (1 << hugepd_shift(*(hugepd_t *)pgd)); 679 #endif 680 free_hugepd_range(tlb, (hugepd_t *)pgd, PGDIR_SHIFT, 681 addr, next, floor, ceiling); 682 } 683 } while (addr = next, addr != end); 684 } 685 686 struct page * 687 follow_huge_addr(struct mm_struct *mm, unsigned long address, int write) 688 { 689 pte_t *ptep; 690 struct page *page; 691 unsigned shift; 692 unsigned long mask; 693 /* 694 * Transparent hugepages are handled by generic code. We can skip them 695 * here. 696 */ 697 ptep = find_linux_pte_or_hugepte(mm->pgd, address, &shift); 698 699 /* Verify it is a huge page else bail. */ 700 if (!ptep || !shift || pmd_trans_huge(*(pmd_t *)ptep)) 701 return ERR_PTR(-EINVAL); 702 703 mask = (1UL << shift) - 1; 704 page = pte_page(*ptep); 705 if (page) 706 page += (address & mask) / PAGE_SIZE; 707 708 return page; 709 } 710 711 struct page * 712 follow_huge_pmd(struct mm_struct *mm, unsigned long address, 713 pmd_t *pmd, int write) 714 { 715 BUG(); 716 return NULL; 717 } 718 719 static unsigned long hugepte_addr_end(unsigned long addr, unsigned long end, 720 unsigned long sz) 721 { 722 unsigned long __boundary = (addr + sz) & ~(sz-1); 723 return (__boundary - 1 < end - 1) ? __boundary : end; 724 } 725 726 int gup_hugepd(hugepd_t *hugepd, unsigned pdshift, 727 unsigned long addr, unsigned long end, 728 int write, struct page **pages, int *nr) 729 { 730 pte_t *ptep; 731 unsigned long sz = 1UL << hugepd_shift(*hugepd); 732 unsigned long next; 733 734 ptep = hugepte_offset(hugepd, addr, pdshift); 735 do { 736 next = hugepte_addr_end(addr, end, sz); 737 if (!gup_hugepte(ptep, sz, addr, end, write, pages, nr)) 738 return 0; 739 } while (ptep++, addr = next, addr != end); 740 741 return 1; 742 } 743 744 #ifdef CONFIG_PPC_MM_SLICES 745 unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr, 746 unsigned long len, unsigned long pgoff, 747 unsigned long flags) 748 { 749 struct hstate *hstate = hstate_file(file); 750 int mmu_psize = shift_to_mmu_psize(huge_page_shift(hstate)); 751 752 return slice_get_unmapped_area(addr, len, flags, mmu_psize, 1); 753 } 754 #endif 755 756 unsigned long vma_mmu_pagesize(struct vm_area_struct *vma) 757 { 758 #ifdef CONFIG_PPC_MM_SLICES 759 unsigned int psize = get_slice_psize(vma->vm_mm, vma->vm_start); 760 761 return 1UL << mmu_psize_to_shift(psize); 762 #else 763 if (!is_vm_hugetlb_page(vma)) 764 return PAGE_SIZE; 765 766 return huge_page_size(hstate_vma(vma)); 767 #endif 768 } 769 770 static inline bool is_power_of_4(unsigned long x) 771 { 772 if (is_power_of_2(x)) 773 return (__ilog2(x) % 2) ? false : true; 774 return false; 775 } 776 777 static int __init add_huge_page_size(unsigned long long size) 778 { 779 int shift = __ffs(size); 780 int mmu_psize; 781 782 /* Check that it is a page size supported by the hardware and 783 * that it fits within pagetable and slice limits. */ 784 #ifdef CONFIG_PPC_FSL_BOOK3E 785 if ((size < PAGE_SIZE) || !is_power_of_4(size)) 786 return -EINVAL; 787 #else 788 if (!is_power_of_2(size) 789 || (shift > SLICE_HIGH_SHIFT) || (shift <= PAGE_SHIFT)) 790 return -EINVAL; 791 #endif 792 793 if ((mmu_psize = shift_to_mmu_psize(shift)) < 0) 794 return -EINVAL; 795 796 #ifdef CONFIG_SPU_FS_64K_LS 797 /* Disable support for 64K huge pages when 64K SPU local store 798 * support is enabled as the current implementation conflicts. 799 */ 800 if (shift == PAGE_SHIFT_64K) 801 return -EINVAL; 802 #endif /* CONFIG_SPU_FS_64K_LS */ 803 804 BUG_ON(mmu_psize_defs[mmu_psize].shift != shift); 805 806 /* Return if huge page size has already been setup */ 807 if (size_to_hstate(size)) 808 return 0; 809 810 hugetlb_add_hstate(shift - PAGE_SHIFT); 811 812 return 0; 813 } 814 815 static int __init hugepage_setup_sz(char *str) 816 { 817 unsigned long long size; 818 819 size = memparse(str, &str); 820 821 if (add_huge_page_size(size) != 0) 822 printk(KERN_WARNING "Invalid huge page size specified(%llu)\n", size); 823 824 return 1; 825 } 826 __setup("hugepagesz=", hugepage_setup_sz); 827 828 #ifdef CONFIG_PPC_FSL_BOOK3E 829 struct kmem_cache *hugepte_cache; 830 static int __init hugetlbpage_init(void) 831 { 832 int psize; 833 834 for (psize = 0; psize < MMU_PAGE_COUNT; ++psize) { 835 unsigned shift; 836 837 if (!mmu_psize_defs[psize].shift) 838 continue; 839 840 shift = mmu_psize_to_shift(psize); 841 842 /* Don't treat normal page sizes as huge... */ 843 if (shift != PAGE_SHIFT) 844 if (add_huge_page_size(1ULL << shift) < 0) 845 continue; 846 } 847 848 /* 849 * Create a kmem cache for hugeptes. The bottom bits in the pte have 850 * size information encoded in them, so align them to allow this 851 */ 852 hugepte_cache = kmem_cache_create("hugepte-cache", sizeof(pte_t), 853 HUGEPD_SHIFT_MASK + 1, 0, NULL); 854 if (hugepte_cache == NULL) 855 panic("%s: Unable to create kmem cache for hugeptes\n", 856 __func__); 857 858 /* Default hpage size = 4M */ 859 if (mmu_psize_defs[MMU_PAGE_4M].shift) 860 HPAGE_SHIFT = mmu_psize_defs[MMU_PAGE_4M].shift; 861 else 862 panic("%s: Unable to set default huge page size\n", __func__); 863 864 865 return 0; 866 } 867 #else 868 static int __init hugetlbpage_init(void) 869 { 870 int psize; 871 872 if (!mmu_has_feature(MMU_FTR_16M_PAGE)) 873 return -ENODEV; 874 875 for (psize = 0; psize < MMU_PAGE_COUNT; ++psize) { 876 unsigned shift; 877 unsigned pdshift; 878 879 if (!mmu_psize_defs[psize].shift) 880 continue; 881 882 shift = mmu_psize_to_shift(psize); 883 884 if (add_huge_page_size(1ULL << shift) < 0) 885 continue; 886 887 if (shift < PMD_SHIFT) 888 pdshift = PMD_SHIFT; 889 else if (shift < PUD_SHIFT) 890 pdshift = PUD_SHIFT; 891 else 892 pdshift = PGDIR_SHIFT; 893 /* 894 * if we have pdshift and shift value same, we don't 895 * use pgt cache for hugepd. 896 */ 897 if (pdshift != shift) { 898 pgtable_cache_add(pdshift - shift, NULL); 899 if (!PGT_CACHE(pdshift - shift)) 900 panic("hugetlbpage_init(): could not create " 901 "pgtable cache for %d bit pagesize\n", shift); 902 } 903 } 904 905 /* Set default large page size. Currently, we pick 16M or 1M 906 * depending on what is available 907 */ 908 if (mmu_psize_defs[MMU_PAGE_16M].shift) 909 HPAGE_SHIFT = mmu_psize_defs[MMU_PAGE_16M].shift; 910 else if (mmu_psize_defs[MMU_PAGE_1M].shift) 911 HPAGE_SHIFT = mmu_psize_defs[MMU_PAGE_1M].shift; 912 913 return 0; 914 } 915 #endif 916 module_init(hugetlbpage_init); 917 918 void flush_dcache_icache_hugepage(struct page *page) 919 { 920 int i; 921 void *start; 922 923 BUG_ON(!PageCompound(page)); 924 925 for (i = 0; i < (1UL << compound_order(page)); i++) { 926 if (!PageHighMem(page)) { 927 __flush_dcache_icache(page_address(page+i)); 928 } else { 929 start = kmap_atomic(page+i); 930 __flush_dcache_icache(start); 931 kunmap_atomic(start); 932 } 933 } 934 } 935 936 #endif /* CONFIG_HUGETLB_PAGE */ 937 938 /* 939 * We have 4 cases for pgds and pmds: 940 * (1) invalid (all zeroes) 941 * (2) pointer to next table, as normal; bottom 6 bits == 0 942 * (3) leaf pte for huge page, bottom two bits != 00 943 * (4) hugepd pointer, bottom two bits == 00, next 4 bits indicate size of table 944 * 945 * So long as we atomically load page table pointers we are safe against teardown, 946 * we can follow the address down to the the page and take a ref on it. 947 */ 948 949 pte_t *find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea, unsigned *shift) 950 { 951 pgd_t pgd, *pgdp; 952 pud_t pud, *pudp; 953 pmd_t pmd, *pmdp; 954 pte_t *ret_pte; 955 hugepd_t *hpdp = NULL; 956 unsigned pdshift = PGDIR_SHIFT; 957 958 if (shift) 959 *shift = 0; 960 961 pgdp = pgdir + pgd_index(ea); 962 pgd = ACCESS_ONCE(*pgdp); 963 /* 964 * Always operate on the local stack value. This make sure the 965 * value don't get updated by a parallel THP split/collapse, 966 * page fault or a page unmap. The return pte_t * is still not 967 * stable. So should be checked there for above conditions. 968 */ 969 if (pgd_none(pgd)) 970 return NULL; 971 else if (pgd_huge(pgd)) { 972 ret_pte = (pte_t *) pgdp; 973 goto out; 974 } else if (is_hugepd(&pgd)) 975 hpdp = (hugepd_t *)&pgd; 976 else { 977 /* 978 * Even if we end up with an unmap, the pgtable will not 979 * be freed, because we do an rcu free and here we are 980 * irq disabled 981 */ 982 pdshift = PUD_SHIFT; 983 pudp = pud_offset(&pgd, ea); 984 pud = ACCESS_ONCE(*pudp); 985 986 if (pud_none(pud)) 987 return NULL; 988 else if (pud_huge(pud)) { 989 ret_pte = (pte_t *) pudp; 990 goto out; 991 } else if (is_hugepd(&pud)) 992 hpdp = (hugepd_t *)&pud; 993 else { 994 pdshift = PMD_SHIFT; 995 pmdp = pmd_offset(&pud, ea); 996 pmd = ACCESS_ONCE(*pmdp); 997 /* 998 * A hugepage collapse is captured by pmd_none, because 999 * it mark the pmd none and do a hpte invalidate. 1000 * 1001 * A hugepage split is captured by pmd_trans_splitting 1002 * because we mark the pmd trans splitting and do a 1003 * hpte invalidate 1004 * 1005 */ 1006 if (pmd_none(pmd) || pmd_trans_splitting(pmd)) 1007 return NULL; 1008 1009 if (pmd_huge(pmd) || pmd_large(pmd)) { 1010 ret_pte = (pte_t *) pmdp; 1011 goto out; 1012 } else if (is_hugepd(&pmd)) 1013 hpdp = (hugepd_t *)&pmd; 1014 else 1015 return pte_offset_kernel(&pmd, ea); 1016 } 1017 } 1018 if (!hpdp) 1019 return NULL; 1020 1021 ret_pte = hugepte_offset(hpdp, ea, pdshift); 1022 pdshift = hugepd_shift(*hpdp); 1023 out: 1024 if (shift) 1025 *shift = pdshift; 1026 return ret_pte; 1027 } 1028 EXPORT_SYMBOL_GPL(find_linux_pte_or_hugepte); 1029 1030 int gup_hugepte(pte_t *ptep, unsigned long sz, unsigned long addr, 1031 unsigned long end, int write, struct page **pages, int *nr) 1032 { 1033 unsigned long mask; 1034 unsigned long pte_end; 1035 struct page *head, *page, *tail; 1036 pte_t pte; 1037 int refs; 1038 1039 pte_end = (addr + sz) & ~(sz-1); 1040 if (pte_end < end) 1041 end = pte_end; 1042 1043 pte = ACCESS_ONCE(*ptep); 1044 mask = _PAGE_PRESENT | _PAGE_USER; 1045 if (write) 1046 mask |= _PAGE_RW; 1047 1048 if ((pte_val(pte) & mask) != mask) 1049 return 0; 1050 1051 #ifdef CONFIG_TRANSPARENT_HUGEPAGE 1052 /* 1053 * check for splitting here 1054 */ 1055 if (pmd_trans_splitting(pte_pmd(pte))) 1056 return 0; 1057 #endif 1058 1059 /* hugepages are never "special" */ 1060 VM_BUG_ON(!pfn_valid(pte_pfn(pte))); 1061 1062 refs = 0; 1063 head = pte_page(pte); 1064 1065 page = head + ((addr & (sz-1)) >> PAGE_SHIFT); 1066 tail = page; 1067 do { 1068 VM_BUG_ON(compound_head(page) != head); 1069 pages[*nr] = page; 1070 (*nr)++; 1071 page++; 1072 refs++; 1073 } while (addr += PAGE_SIZE, addr != end); 1074 1075 if (!page_cache_add_speculative(head, refs)) { 1076 *nr -= refs; 1077 return 0; 1078 } 1079 1080 if (unlikely(pte_val(pte) != pte_val(*ptep))) { 1081 /* Could be optimized better */ 1082 *nr -= refs; 1083 while (refs--) 1084 put_page(head); 1085 return 0; 1086 } 1087 1088 /* 1089 * Any tail page need their mapcount reference taken before we 1090 * return. 1091 */ 1092 while (refs--) { 1093 if (PageTail(tail)) 1094 get_huge_page_tail(tail); 1095 tail++; 1096 } 1097 1098 return 1; 1099 } 1100