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 * Defined in such a way that we can optimize away code block at build time 67 * if CONFIG_HUGETLB_PAGE=n. 68 */ 69 int pmd_huge(pmd_t pmd) 70 { 71 /* 72 * leaf pte for huge page, bottom two bits != 00 73 */ 74 return ((pmd_val(pmd) & 0x3) != 0x0); 75 } 76 77 int pud_huge(pud_t pud) 78 { 79 /* 80 * leaf pte for huge page, bottom two bits != 00 81 */ 82 return ((pud_val(pud) & 0x3) != 0x0); 83 } 84 85 int pgd_huge(pgd_t pgd) 86 { 87 /* 88 * leaf pte for huge page, bottom two bits != 00 89 */ 90 return ((pgd_val(pgd) & 0x3) != 0x0); 91 } 92 #else 93 int pmd_huge(pmd_t pmd) 94 { 95 return 0; 96 } 97 98 int pud_huge(pud_t pud) 99 { 100 return 0; 101 } 102 103 int pgd_huge(pgd_t pgd) 104 { 105 return 0; 106 } 107 #endif 108 109 pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr) 110 { 111 /* Only called for hugetlbfs pages, hence can ignore THP */ 112 return find_linux_pte_or_hugepte(mm->pgd, addr, NULL); 113 } 114 115 static int __hugepte_alloc(struct mm_struct *mm, hugepd_t *hpdp, 116 unsigned long address, unsigned pdshift, unsigned pshift) 117 { 118 struct kmem_cache *cachep; 119 pte_t *new; 120 121 #ifdef CONFIG_PPC_FSL_BOOK3E 122 int i; 123 int num_hugepd = 1 << (pshift - pdshift); 124 cachep = hugepte_cache; 125 #else 126 cachep = PGT_CACHE(pdshift - pshift); 127 #endif 128 129 new = kmem_cache_zalloc(cachep, GFP_KERNEL|__GFP_REPEAT); 130 131 BUG_ON(pshift > HUGEPD_SHIFT_MASK); 132 BUG_ON((unsigned long)new & HUGEPD_SHIFT_MASK); 133 134 if (! new) 135 return -ENOMEM; 136 137 spin_lock(&mm->page_table_lock); 138 #ifdef CONFIG_PPC_FSL_BOOK3E 139 /* 140 * We have multiple higher-level entries that point to the same 141 * actual pte location. Fill in each as we go and backtrack on error. 142 * We need all of these so the DTLB pgtable walk code can find the 143 * right higher-level entry without knowing if it's a hugepage or not. 144 */ 145 for (i = 0; i < num_hugepd; i++, hpdp++) { 146 if (unlikely(!hugepd_none(*hpdp))) 147 break; 148 else 149 /* We use the old format for PPC_FSL_BOOK3E */ 150 hpdp->pd = ((unsigned long)new & ~PD_HUGE) | pshift; 151 } 152 /* If we bailed from the for loop early, an error occurred, clean up */ 153 if (i < num_hugepd) { 154 for (i = i - 1 ; i >= 0; i--, hpdp--) 155 hpdp->pd = 0; 156 kmem_cache_free(cachep, new); 157 } 158 #else 159 if (!hugepd_none(*hpdp)) 160 kmem_cache_free(cachep, new); 161 else { 162 #ifdef CONFIG_PPC_BOOK3S_64 163 hpdp->pd = (unsigned long)new | 164 (shift_to_mmu_psize(pshift) << 2); 165 #else 166 hpdp->pd = ((unsigned long)new & ~PD_HUGE) | pshift; 167 #endif 168 } 169 #endif 170 spin_unlock(&mm->page_table_lock); 171 return 0; 172 } 173 174 /* 175 * These macros define how to determine which level of the page table holds 176 * the hpdp. 177 */ 178 #ifdef CONFIG_PPC_FSL_BOOK3E 179 #define HUGEPD_PGD_SHIFT PGDIR_SHIFT 180 #define HUGEPD_PUD_SHIFT PUD_SHIFT 181 #else 182 #define HUGEPD_PGD_SHIFT PUD_SHIFT 183 #define HUGEPD_PUD_SHIFT PMD_SHIFT 184 #endif 185 186 #ifdef CONFIG_PPC_BOOK3S_64 187 /* 188 * At this point we do the placement change only for BOOK3S 64. This would 189 * possibly work on other subarchs. 190 */ 191 pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned long sz) 192 { 193 pgd_t *pg; 194 pud_t *pu; 195 pmd_t *pm; 196 hugepd_t *hpdp = NULL; 197 unsigned pshift = __ffs(sz); 198 unsigned pdshift = PGDIR_SHIFT; 199 200 addr &= ~(sz-1); 201 pg = pgd_offset(mm, addr); 202 203 if (pshift == PGDIR_SHIFT) 204 /* 16GB huge page */ 205 return (pte_t *) pg; 206 else if (pshift > PUD_SHIFT) 207 /* 208 * We need to use hugepd table 209 */ 210 hpdp = (hugepd_t *)pg; 211 else { 212 pdshift = PUD_SHIFT; 213 pu = pud_alloc(mm, pg, addr); 214 if (pshift == PUD_SHIFT) 215 return (pte_t *)pu; 216 else if (pshift > PMD_SHIFT) 217 hpdp = (hugepd_t *)pu; 218 else { 219 pdshift = PMD_SHIFT; 220 pm = pmd_alloc(mm, pu, addr); 221 if (pshift == PMD_SHIFT) 222 /* 16MB hugepage */ 223 return (pte_t *)pm; 224 else 225 hpdp = (hugepd_t *)pm; 226 } 227 } 228 if (!hpdp) 229 return NULL; 230 231 BUG_ON(!hugepd_none(*hpdp) && !hugepd_ok(*hpdp)); 232 233 if (hugepd_none(*hpdp) && __hugepte_alloc(mm, hpdp, addr, pdshift, pshift)) 234 return NULL; 235 236 return hugepte_offset(*hpdp, addr, pdshift); 237 } 238 239 #else 240 241 pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned long sz) 242 { 243 pgd_t *pg; 244 pud_t *pu; 245 pmd_t *pm; 246 hugepd_t *hpdp = NULL; 247 unsigned pshift = __ffs(sz); 248 unsigned pdshift = PGDIR_SHIFT; 249 250 addr &= ~(sz-1); 251 252 pg = pgd_offset(mm, addr); 253 254 if (pshift >= HUGEPD_PGD_SHIFT) { 255 hpdp = (hugepd_t *)pg; 256 } else { 257 pdshift = PUD_SHIFT; 258 pu = pud_alloc(mm, pg, addr); 259 if (pshift >= HUGEPD_PUD_SHIFT) { 260 hpdp = (hugepd_t *)pu; 261 } else { 262 pdshift = PMD_SHIFT; 263 pm = pmd_alloc(mm, pu, addr); 264 hpdp = (hugepd_t *)pm; 265 } 266 } 267 268 if (!hpdp) 269 return NULL; 270 271 BUG_ON(!hugepd_none(*hpdp) && !hugepd_ok(*hpdp)); 272 273 if (hugepd_none(*hpdp) && __hugepte_alloc(mm, hpdp, addr, pdshift, pshift)) 274 return NULL; 275 276 return hugepte_offset(*hpdp, addr, pdshift); 277 } 278 #endif 279 280 #ifdef CONFIG_PPC_FSL_BOOK3E 281 /* Build list of addresses of gigantic pages. This function is used in early 282 * boot before the buddy allocator is setup. 283 */ 284 void add_gpage(u64 addr, u64 page_size, unsigned long number_of_pages) 285 { 286 unsigned int idx = shift_to_mmu_psize(__ffs(page_size)); 287 int i; 288 289 if (addr == 0) 290 return; 291 292 gpage_freearray[idx].nr_gpages = number_of_pages; 293 294 for (i = 0; i < number_of_pages; i++) { 295 gpage_freearray[idx].gpage_list[i] = addr; 296 addr += page_size; 297 } 298 } 299 300 /* 301 * Moves the gigantic page addresses from the temporary list to the 302 * huge_boot_pages list. 303 */ 304 int alloc_bootmem_huge_page(struct hstate *hstate) 305 { 306 struct huge_bootmem_page *m; 307 int idx = shift_to_mmu_psize(huge_page_shift(hstate)); 308 int nr_gpages = gpage_freearray[idx].nr_gpages; 309 310 if (nr_gpages == 0) 311 return 0; 312 313 #ifdef CONFIG_HIGHMEM 314 /* 315 * If gpages can be in highmem we can't use the trick of storing the 316 * data structure in the page; allocate space for this 317 */ 318 m = memblock_virt_alloc(sizeof(struct huge_bootmem_page), 0); 319 m->phys = gpage_freearray[idx].gpage_list[--nr_gpages]; 320 #else 321 m = phys_to_virt(gpage_freearray[idx].gpage_list[--nr_gpages]); 322 #endif 323 324 list_add(&m->list, &huge_boot_pages); 325 gpage_freearray[idx].nr_gpages = nr_gpages; 326 gpage_freearray[idx].gpage_list[nr_gpages] = 0; 327 m->hstate = hstate; 328 329 return 1; 330 } 331 /* 332 * Scan the command line hugepagesz= options for gigantic pages; store those in 333 * a list that we use to allocate the memory once all options are parsed. 334 */ 335 336 unsigned long gpage_npages[MMU_PAGE_COUNT]; 337 338 static int __init do_gpage_early_setup(char *param, char *val, 339 const char *unused) 340 { 341 static phys_addr_t size; 342 unsigned long npages; 343 344 /* 345 * The hugepagesz and hugepages cmdline options are interleaved. We 346 * use the size variable to keep track of whether or not this was done 347 * properly and skip over instances where it is incorrect. Other 348 * command-line parsing code will issue warnings, so we don't need to. 349 * 350 */ 351 if ((strcmp(param, "default_hugepagesz") == 0) || 352 (strcmp(param, "hugepagesz") == 0)) { 353 size = memparse(val, NULL); 354 } else if (strcmp(param, "hugepages") == 0) { 355 if (size != 0) { 356 if (sscanf(val, "%lu", &npages) <= 0) 357 npages = 0; 358 if (npages > MAX_NUMBER_GPAGES) { 359 pr_warn("MMU: %lu pages requested for page " 360 "size %llu KB, limiting to " 361 __stringify(MAX_NUMBER_GPAGES) "\n", 362 npages, size / 1024); 363 npages = MAX_NUMBER_GPAGES; 364 } 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 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 = this_cpu_ptr(&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 #ifdef CONFIG_PPC_FSL_BOOK3E 531 hugepd_free(tlb, hugepte); 532 #else 533 pgtable_free_tlb(tlb, hugepte, pdshift - shift); 534 #endif 535 } 536 537 static void hugetlb_free_pmd_range(struct mmu_gather *tlb, pud_t *pud, 538 unsigned long addr, unsigned long end, 539 unsigned long floor, unsigned long ceiling) 540 { 541 pmd_t *pmd; 542 unsigned long next; 543 unsigned long start; 544 545 start = addr; 546 do { 547 pmd = pmd_offset(pud, addr); 548 next = pmd_addr_end(addr, end); 549 if (!is_hugepd(__hugepd(pmd_val(*pmd)))) { 550 /* 551 * if it is not hugepd pointer, we should already find 552 * it cleared. 553 */ 554 WARN_ON(!pmd_none_or_clear_bad(pmd)); 555 continue; 556 } 557 #ifdef CONFIG_PPC_FSL_BOOK3E 558 /* 559 * Increment next by the size of the huge mapping since 560 * there may be more than one entry at this level for a 561 * single hugepage, but all of them point to 562 * the same kmem cache that holds the hugepte. 563 */ 564 next = addr + (1 << hugepd_shift(*(hugepd_t *)pmd)); 565 #endif 566 free_hugepd_range(tlb, (hugepd_t *)pmd, PMD_SHIFT, 567 addr, next, floor, ceiling); 568 } while (addr = next, addr != end); 569 570 start &= PUD_MASK; 571 if (start < floor) 572 return; 573 if (ceiling) { 574 ceiling &= PUD_MASK; 575 if (!ceiling) 576 return; 577 } 578 if (end - 1 > ceiling - 1) 579 return; 580 581 pmd = pmd_offset(pud, start); 582 pud_clear(pud); 583 pmd_free_tlb(tlb, pmd, start); 584 } 585 586 static void hugetlb_free_pud_range(struct mmu_gather *tlb, pgd_t *pgd, 587 unsigned long addr, unsigned long end, 588 unsigned long floor, unsigned long ceiling) 589 { 590 pud_t *pud; 591 unsigned long next; 592 unsigned long start; 593 594 start = addr; 595 do { 596 pud = pud_offset(pgd, addr); 597 next = pud_addr_end(addr, end); 598 if (!is_hugepd(__hugepd(pud_val(*pud)))) { 599 if (pud_none_or_clear_bad(pud)) 600 continue; 601 hugetlb_free_pmd_range(tlb, pud, addr, next, floor, 602 ceiling); 603 } else { 604 #ifdef CONFIG_PPC_FSL_BOOK3E 605 /* 606 * Increment next by the size of the huge mapping since 607 * there may be more than one entry at this level for a 608 * single hugepage, but all of them point to 609 * the same kmem cache that holds the hugepte. 610 */ 611 next = addr + (1 << hugepd_shift(*(hugepd_t *)pud)); 612 #endif 613 free_hugepd_range(tlb, (hugepd_t *)pud, PUD_SHIFT, 614 addr, next, floor, ceiling); 615 } 616 } while (addr = next, addr != end); 617 618 start &= PGDIR_MASK; 619 if (start < floor) 620 return; 621 if (ceiling) { 622 ceiling &= PGDIR_MASK; 623 if (!ceiling) 624 return; 625 } 626 if (end - 1 > ceiling - 1) 627 return; 628 629 pud = pud_offset(pgd, start); 630 pgd_clear(pgd); 631 pud_free_tlb(tlb, pud, start); 632 } 633 634 /* 635 * This function frees user-level page tables of a process. 636 */ 637 void hugetlb_free_pgd_range(struct mmu_gather *tlb, 638 unsigned long addr, unsigned long end, 639 unsigned long floor, unsigned long ceiling) 640 { 641 pgd_t *pgd; 642 unsigned long next; 643 644 /* 645 * Because there are a number of different possible pagetable 646 * layouts for hugepage ranges, we limit knowledge of how 647 * things should be laid out to the allocation path 648 * (huge_pte_alloc(), above). Everything else works out the 649 * structure as it goes from information in the hugepd 650 * pointers. That means that we can't here use the 651 * optimization used in the normal page free_pgd_range(), of 652 * checking whether we're actually covering a large enough 653 * range to have to do anything at the top level of the walk 654 * instead of at the bottom. 655 * 656 * To make sense of this, you should probably go read the big 657 * block comment at the top of the normal free_pgd_range(), 658 * too. 659 */ 660 661 do { 662 next = pgd_addr_end(addr, end); 663 pgd = pgd_offset(tlb->mm, addr); 664 if (!is_hugepd(__hugepd(pgd_val(*pgd)))) { 665 if (pgd_none_or_clear_bad(pgd)) 666 continue; 667 hugetlb_free_pud_range(tlb, pgd, addr, next, floor, ceiling); 668 } else { 669 #ifdef CONFIG_PPC_FSL_BOOK3E 670 /* 671 * Increment next by the size of the huge mapping since 672 * there may be more than one entry at the pgd level 673 * for a single hugepage, but all of them point to the 674 * same kmem cache that holds the hugepte. 675 */ 676 next = addr + (1 << hugepd_shift(*(hugepd_t *)pgd)); 677 #endif 678 free_hugepd_range(tlb, (hugepd_t *)pgd, PGDIR_SHIFT, 679 addr, next, floor, ceiling); 680 } 681 } while (addr = next, addr != end); 682 } 683 684 struct page * 685 follow_huge_addr(struct mm_struct *mm, unsigned long address, int write) 686 { 687 pte_t *ptep; 688 struct page *page; 689 unsigned shift; 690 unsigned long mask; 691 /* 692 * Transparent hugepages are handled by generic code. We can skip them 693 * here. 694 */ 695 ptep = find_linux_pte_or_hugepte(mm->pgd, address, &shift); 696 697 /* Verify it is a huge page else bail. */ 698 if (!ptep || !shift || pmd_trans_huge(*(pmd_t *)ptep)) 699 return ERR_PTR(-EINVAL); 700 701 mask = (1UL << shift) - 1; 702 page = pte_page(*ptep); 703 if (page) 704 page += (address & mask) / PAGE_SIZE; 705 706 return page; 707 } 708 709 struct page * 710 follow_huge_pmd(struct mm_struct *mm, unsigned long address, 711 pmd_t *pmd, int write) 712 { 713 BUG(); 714 return NULL; 715 } 716 717 struct page * 718 follow_huge_pud(struct mm_struct *mm, unsigned long address, 719 pud_t *pud, int write) 720 { 721 BUG(); 722 return NULL; 723 } 724 725 static unsigned long hugepte_addr_end(unsigned long addr, unsigned long end, 726 unsigned long sz) 727 { 728 unsigned long __boundary = (addr + sz) & ~(sz-1); 729 return (__boundary - 1 < end - 1) ? __boundary : end; 730 } 731 732 int gup_huge_pd(hugepd_t hugepd, unsigned long addr, unsigned pdshift, 733 unsigned long end, int write, struct page **pages, int *nr) 734 { 735 pte_t *ptep; 736 unsigned long sz = 1UL << hugepd_shift(hugepd); 737 unsigned long next; 738 739 ptep = hugepte_offset(hugepd, addr, pdshift); 740 do { 741 next = hugepte_addr_end(addr, end, sz); 742 if (!gup_hugepte(ptep, sz, addr, end, write, pages, nr)) 743 return 0; 744 } while (ptep++, addr = next, addr != end); 745 746 return 1; 747 } 748 749 #ifdef CONFIG_PPC_MM_SLICES 750 unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr, 751 unsigned long len, unsigned long pgoff, 752 unsigned long flags) 753 { 754 struct hstate *hstate = hstate_file(file); 755 int mmu_psize = shift_to_mmu_psize(huge_page_shift(hstate)); 756 757 return slice_get_unmapped_area(addr, len, flags, mmu_psize, 1); 758 } 759 #endif 760 761 unsigned long vma_mmu_pagesize(struct vm_area_struct *vma) 762 { 763 #ifdef CONFIG_PPC_MM_SLICES 764 unsigned int psize = get_slice_psize(vma->vm_mm, vma->vm_start); 765 766 return 1UL << mmu_psize_to_shift(psize); 767 #else 768 if (!is_vm_hugetlb_page(vma)) 769 return PAGE_SIZE; 770 771 return huge_page_size(hstate_vma(vma)); 772 #endif 773 } 774 775 static inline bool is_power_of_4(unsigned long x) 776 { 777 if (is_power_of_2(x)) 778 return (__ilog2(x) % 2) ? false : true; 779 return false; 780 } 781 782 static int __init add_huge_page_size(unsigned long long size) 783 { 784 int shift = __ffs(size); 785 int mmu_psize; 786 787 /* Check that it is a page size supported by the hardware and 788 * that it fits within pagetable and slice limits. */ 789 #ifdef CONFIG_PPC_FSL_BOOK3E 790 if ((size < PAGE_SIZE) || !is_power_of_4(size)) 791 return -EINVAL; 792 #else 793 if (!is_power_of_2(size) 794 || (shift > SLICE_HIGH_SHIFT) || (shift <= PAGE_SHIFT)) 795 return -EINVAL; 796 #endif 797 798 if ((mmu_psize = shift_to_mmu_psize(shift)) < 0) 799 return -EINVAL; 800 801 #ifdef CONFIG_SPU_FS_64K_LS 802 /* Disable support for 64K huge pages when 64K SPU local store 803 * support is enabled as the current implementation conflicts. 804 */ 805 if (shift == PAGE_SHIFT_64K) 806 return -EINVAL; 807 #endif /* CONFIG_SPU_FS_64K_LS */ 808 809 BUG_ON(mmu_psize_defs[mmu_psize].shift != shift); 810 811 /* Return if huge page size has already been setup */ 812 if (size_to_hstate(size)) 813 return 0; 814 815 hugetlb_add_hstate(shift - PAGE_SHIFT); 816 817 return 0; 818 } 819 820 static int __init hugepage_setup_sz(char *str) 821 { 822 unsigned long long size; 823 824 size = memparse(str, &str); 825 826 if (add_huge_page_size(size) != 0) 827 printk(KERN_WARNING "Invalid huge page size specified(%llu)\n", size); 828 829 return 1; 830 } 831 __setup("hugepagesz=", hugepage_setup_sz); 832 833 #ifdef CONFIG_PPC_FSL_BOOK3E 834 struct kmem_cache *hugepte_cache; 835 static int __init hugetlbpage_init(void) 836 { 837 int psize; 838 839 for (psize = 0; psize < MMU_PAGE_COUNT; ++psize) { 840 unsigned shift; 841 842 if (!mmu_psize_defs[psize].shift) 843 continue; 844 845 shift = mmu_psize_to_shift(psize); 846 847 /* Don't treat normal page sizes as huge... */ 848 if (shift != PAGE_SHIFT) 849 if (add_huge_page_size(1ULL << shift) < 0) 850 continue; 851 } 852 853 /* 854 * Create a kmem cache for hugeptes. The bottom bits in the pte have 855 * size information encoded in them, so align them to allow this 856 */ 857 hugepte_cache = kmem_cache_create("hugepte-cache", sizeof(pte_t), 858 HUGEPD_SHIFT_MASK + 1, 0, NULL); 859 if (hugepte_cache == NULL) 860 panic("%s: Unable to create kmem cache for hugeptes\n", 861 __func__); 862 863 /* Default hpage size = 4M */ 864 if (mmu_psize_defs[MMU_PAGE_4M].shift) 865 HPAGE_SHIFT = mmu_psize_defs[MMU_PAGE_4M].shift; 866 else 867 panic("%s: Unable to set default huge page size\n", __func__); 868 869 870 return 0; 871 } 872 #else 873 static int __init hugetlbpage_init(void) 874 { 875 int psize; 876 877 if (!mmu_has_feature(MMU_FTR_16M_PAGE)) 878 return -ENODEV; 879 880 for (psize = 0; psize < MMU_PAGE_COUNT; ++psize) { 881 unsigned shift; 882 unsigned pdshift; 883 884 if (!mmu_psize_defs[psize].shift) 885 continue; 886 887 shift = mmu_psize_to_shift(psize); 888 889 if (add_huge_page_size(1ULL << shift) < 0) 890 continue; 891 892 if (shift < PMD_SHIFT) 893 pdshift = PMD_SHIFT; 894 else if (shift < PUD_SHIFT) 895 pdshift = PUD_SHIFT; 896 else 897 pdshift = PGDIR_SHIFT; 898 /* 899 * if we have pdshift and shift value same, we don't 900 * use pgt cache for hugepd. 901 */ 902 if (pdshift != shift) { 903 pgtable_cache_add(pdshift - shift, NULL); 904 if (!PGT_CACHE(pdshift - shift)) 905 panic("hugetlbpage_init(): could not create " 906 "pgtable cache for %d bit pagesize\n", shift); 907 } 908 } 909 910 /* Set default large page size. Currently, we pick 16M or 1M 911 * depending on what is available 912 */ 913 if (mmu_psize_defs[MMU_PAGE_16M].shift) 914 HPAGE_SHIFT = mmu_psize_defs[MMU_PAGE_16M].shift; 915 else if (mmu_psize_defs[MMU_PAGE_1M].shift) 916 HPAGE_SHIFT = mmu_psize_defs[MMU_PAGE_1M].shift; 917 918 return 0; 919 } 920 #endif 921 module_init(hugetlbpage_init); 922 923 void flush_dcache_icache_hugepage(struct page *page) 924 { 925 int i; 926 void *start; 927 928 BUG_ON(!PageCompound(page)); 929 930 for (i = 0; i < (1UL << compound_order(page)); i++) { 931 if (!PageHighMem(page)) { 932 __flush_dcache_icache(page_address(page+i)); 933 } else { 934 start = kmap_atomic(page+i); 935 __flush_dcache_icache(start); 936 kunmap_atomic(start); 937 } 938 } 939 } 940 941 #endif /* CONFIG_HUGETLB_PAGE */ 942 943 /* 944 * We have 4 cases for pgds and pmds: 945 * (1) invalid (all zeroes) 946 * (2) pointer to next table, as normal; bottom 6 bits == 0 947 * (3) leaf pte for huge page, bottom two bits != 00 948 * (4) hugepd pointer, bottom two bits == 00, next 4 bits indicate size of table 949 * 950 * So long as we atomically load page table pointers we are safe against teardown, 951 * we can follow the address down to the the page and take a ref on it. 952 */ 953 954 pte_t *find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea, unsigned *shift) 955 { 956 pgd_t pgd, *pgdp; 957 pud_t pud, *pudp; 958 pmd_t pmd, *pmdp; 959 pte_t *ret_pte; 960 hugepd_t *hpdp = NULL; 961 unsigned pdshift = PGDIR_SHIFT; 962 963 if (shift) 964 *shift = 0; 965 966 pgdp = pgdir + pgd_index(ea); 967 pgd = ACCESS_ONCE(*pgdp); 968 /* 969 * Always operate on the local stack value. This make sure the 970 * value don't get updated by a parallel THP split/collapse, 971 * page fault or a page unmap. The return pte_t * is still not 972 * stable. So should be checked there for above conditions. 973 */ 974 if (pgd_none(pgd)) 975 return NULL; 976 else if (pgd_huge(pgd)) { 977 ret_pte = (pte_t *) pgdp; 978 goto out; 979 } else if (is_hugepd(__hugepd(pgd_val(pgd)))) 980 hpdp = (hugepd_t *)&pgd; 981 else { 982 /* 983 * Even if we end up with an unmap, the pgtable will not 984 * be freed, because we do an rcu free and here we are 985 * irq disabled 986 */ 987 pdshift = PUD_SHIFT; 988 pudp = pud_offset(&pgd, ea); 989 pud = READ_ONCE(*pudp); 990 991 if (pud_none(pud)) 992 return NULL; 993 else if (pud_huge(pud)) { 994 ret_pte = (pte_t *) pudp; 995 goto out; 996 } else if (is_hugepd(__hugepd(pud_val(pud)))) 997 hpdp = (hugepd_t *)&pud; 998 else { 999 pdshift = PMD_SHIFT; 1000 pmdp = pmd_offset(&pud, ea); 1001 pmd = READ_ONCE(*pmdp); 1002 /* 1003 * A hugepage collapse is captured by pmd_none, because 1004 * it mark the pmd none and do a hpte invalidate. 1005 * 1006 * A hugepage split is captured by pmd_trans_splitting 1007 * because we mark the pmd trans splitting and do a 1008 * hpte invalidate 1009 * 1010 */ 1011 if (pmd_none(pmd) || pmd_trans_splitting(pmd)) 1012 return NULL; 1013 1014 if (pmd_huge(pmd) || pmd_large(pmd)) { 1015 ret_pte = (pte_t *) pmdp; 1016 goto out; 1017 } else if (is_hugepd(__hugepd(pmd_val(pmd)))) 1018 hpdp = (hugepd_t *)&pmd; 1019 else 1020 return pte_offset_kernel(&pmd, ea); 1021 } 1022 } 1023 if (!hpdp) 1024 return NULL; 1025 1026 ret_pte = hugepte_offset(*hpdp, ea, pdshift); 1027 pdshift = hugepd_shift(*hpdp); 1028 out: 1029 if (shift) 1030 *shift = pdshift; 1031 return ret_pte; 1032 } 1033 EXPORT_SYMBOL_GPL(find_linux_pte_or_hugepte); 1034 1035 int gup_hugepte(pte_t *ptep, unsigned long sz, unsigned long addr, 1036 unsigned long end, int write, struct page **pages, int *nr) 1037 { 1038 unsigned long mask; 1039 unsigned long pte_end; 1040 struct page *head, *page, *tail; 1041 pte_t pte; 1042 int refs; 1043 1044 pte_end = (addr + sz) & ~(sz-1); 1045 if (pte_end < end) 1046 end = pte_end; 1047 1048 pte = ACCESS_ONCE(*ptep); 1049 mask = _PAGE_PRESENT | _PAGE_USER; 1050 if (write) 1051 mask |= _PAGE_RW; 1052 1053 if ((pte_val(pte) & mask) != mask) 1054 return 0; 1055 1056 /* hugepages are never "special" */ 1057 VM_BUG_ON(!pfn_valid(pte_pfn(pte))); 1058 1059 refs = 0; 1060 head = pte_page(pte); 1061 1062 page = head + ((addr & (sz-1)) >> PAGE_SHIFT); 1063 tail = page; 1064 do { 1065 VM_BUG_ON(compound_head(page) != head); 1066 pages[*nr] = page; 1067 (*nr)++; 1068 page++; 1069 refs++; 1070 } while (addr += PAGE_SIZE, addr != end); 1071 1072 if (!page_cache_add_speculative(head, refs)) { 1073 *nr -= refs; 1074 return 0; 1075 } 1076 1077 if (unlikely(pte_val(pte) != pte_val(*ptep))) { 1078 /* Could be optimized better */ 1079 *nr -= refs; 1080 while (refs--) 1081 put_page(head); 1082 return 0; 1083 } 1084 1085 /* 1086 * Any tail page need their mapcount reference taken before we 1087 * return. 1088 */ 1089 while (refs--) { 1090 if (PageTail(tail)) 1091 get_huge_page_tail(tail); 1092 tail++; 1093 } 1094 1095 return 1; 1096 } 1097