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 static unsigned long hugepte_addr_end(unsigned long addr, unsigned long end, 718 unsigned long sz) 719 { 720 unsigned long __boundary = (addr + sz) & ~(sz-1); 721 return (__boundary - 1 < end - 1) ? __boundary : end; 722 } 723 724 int gup_huge_pd(hugepd_t hugepd, unsigned long addr, unsigned pdshift, 725 unsigned long end, int write, struct page **pages, int *nr) 726 { 727 pte_t *ptep; 728 unsigned long sz = 1UL << hugepd_shift(hugepd); 729 unsigned long next; 730 731 ptep = hugepte_offset(hugepd, addr, pdshift); 732 do { 733 next = hugepte_addr_end(addr, end, sz); 734 if (!gup_hugepte(ptep, sz, addr, end, write, pages, nr)) 735 return 0; 736 } while (ptep++, addr = next, addr != end); 737 738 return 1; 739 } 740 741 #ifdef CONFIG_PPC_MM_SLICES 742 unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr, 743 unsigned long len, unsigned long pgoff, 744 unsigned long flags) 745 { 746 struct hstate *hstate = hstate_file(file); 747 int mmu_psize = shift_to_mmu_psize(huge_page_shift(hstate)); 748 749 return slice_get_unmapped_area(addr, len, flags, mmu_psize, 1); 750 } 751 #endif 752 753 unsigned long vma_mmu_pagesize(struct vm_area_struct *vma) 754 { 755 #ifdef CONFIG_PPC_MM_SLICES 756 unsigned int psize = get_slice_psize(vma->vm_mm, vma->vm_start); 757 758 return 1UL << mmu_psize_to_shift(psize); 759 #else 760 if (!is_vm_hugetlb_page(vma)) 761 return PAGE_SIZE; 762 763 return huge_page_size(hstate_vma(vma)); 764 #endif 765 } 766 767 static inline bool is_power_of_4(unsigned long x) 768 { 769 if (is_power_of_2(x)) 770 return (__ilog2(x) % 2) ? false : true; 771 return false; 772 } 773 774 static int __init add_huge_page_size(unsigned long long size) 775 { 776 int shift = __ffs(size); 777 int mmu_psize; 778 779 /* Check that it is a page size supported by the hardware and 780 * that it fits within pagetable and slice limits. */ 781 #ifdef CONFIG_PPC_FSL_BOOK3E 782 if ((size < PAGE_SIZE) || !is_power_of_4(size)) 783 return -EINVAL; 784 #else 785 if (!is_power_of_2(size) 786 || (shift > SLICE_HIGH_SHIFT) || (shift <= PAGE_SHIFT)) 787 return -EINVAL; 788 #endif 789 790 if ((mmu_psize = shift_to_mmu_psize(shift)) < 0) 791 return -EINVAL; 792 793 #ifdef CONFIG_SPU_FS_64K_LS 794 /* Disable support for 64K huge pages when 64K SPU local store 795 * support is enabled as the current implementation conflicts. 796 */ 797 if (shift == PAGE_SHIFT_64K) 798 return -EINVAL; 799 #endif /* CONFIG_SPU_FS_64K_LS */ 800 801 BUG_ON(mmu_psize_defs[mmu_psize].shift != shift); 802 803 /* Return if huge page size has already been setup */ 804 if (size_to_hstate(size)) 805 return 0; 806 807 hugetlb_add_hstate(shift - PAGE_SHIFT); 808 809 return 0; 810 } 811 812 static int __init hugepage_setup_sz(char *str) 813 { 814 unsigned long long size; 815 816 size = memparse(str, &str); 817 818 if (add_huge_page_size(size) != 0) 819 printk(KERN_WARNING "Invalid huge page size specified(%llu)\n", size); 820 821 return 1; 822 } 823 __setup("hugepagesz=", hugepage_setup_sz); 824 825 #ifdef CONFIG_PPC_FSL_BOOK3E 826 struct kmem_cache *hugepte_cache; 827 static int __init hugetlbpage_init(void) 828 { 829 int psize; 830 831 for (psize = 0; psize < MMU_PAGE_COUNT; ++psize) { 832 unsigned shift; 833 834 if (!mmu_psize_defs[psize].shift) 835 continue; 836 837 shift = mmu_psize_to_shift(psize); 838 839 /* Don't treat normal page sizes as huge... */ 840 if (shift != PAGE_SHIFT) 841 if (add_huge_page_size(1ULL << shift) < 0) 842 continue; 843 } 844 845 /* 846 * Create a kmem cache for hugeptes. The bottom bits in the pte have 847 * size information encoded in them, so align them to allow this 848 */ 849 hugepte_cache = kmem_cache_create("hugepte-cache", sizeof(pte_t), 850 HUGEPD_SHIFT_MASK + 1, 0, NULL); 851 if (hugepte_cache == NULL) 852 panic("%s: Unable to create kmem cache for hugeptes\n", 853 __func__); 854 855 /* Default hpage size = 4M */ 856 if (mmu_psize_defs[MMU_PAGE_4M].shift) 857 HPAGE_SHIFT = mmu_psize_defs[MMU_PAGE_4M].shift; 858 else 859 panic("%s: Unable to set default huge page size\n", __func__); 860 861 862 return 0; 863 } 864 #else 865 static int __init hugetlbpage_init(void) 866 { 867 int psize; 868 869 if (!mmu_has_feature(MMU_FTR_16M_PAGE)) 870 return -ENODEV; 871 872 for (psize = 0; psize < MMU_PAGE_COUNT; ++psize) { 873 unsigned shift; 874 unsigned pdshift; 875 876 if (!mmu_psize_defs[psize].shift) 877 continue; 878 879 shift = mmu_psize_to_shift(psize); 880 881 if (add_huge_page_size(1ULL << shift) < 0) 882 continue; 883 884 if (shift < PMD_SHIFT) 885 pdshift = PMD_SHIFT; 886 else if (shift < PUD_SHIFT) 887 pdshift = PUD_SHIFT; 888 else 889 pdshift = PGDIR_SHIFT; 890 /* 891 * if we have pdshift and shift value same, we don't 892 * use pgt cache for hugepd. 893 */ 894 if (pdshift != shift) { 895 pgtable_cache_add(pdshift - shift, NULL); 896 if (!PGT_CACHE(pdshift - shift)) 897 panic("hugetlbpage_init(): could not create " 898 "pgtable cache for %d bit pagesize\n", shift); 899 } 900 } 901 902 /* Set default large page size. Currently, we pick 16M or 1M 903 * depending on what is available 904 */ 905 if (mmu_psize_defs[MMU_PAGE_16M].shift) 906 HPAGE_SHIFT = mmu_psize_defs[MMU_PAGE_16M].shift; 907 else if (mmu_psize_defs[MMU_PAGE_1M].shift) 908 HPAGE_SHIFT = mmu_psize_defs[MMU_PAGE_1M].shift; 909 910 return 0; 911 } 912 #endif 913 module_init(hugetlbpage_init); 914 915 void flush_dcache_icache_hugepage(struct page *page) 916 { 917 int i; 918 void *start; 919 920 BUG_ON(!PageCompound(page)); 921 922 for (i = 0; i < (1UL << compound_order(page)); i++) { 923 if (!PageHighMem(page)) { 924 __flush_dcache_icache(page_address(page+i)); 925 } else { 926 start = kmap_atomic(page+i); 927 __flush_dcache_icache(start); 928 kunmap_atomic(start); 929 } 930 } 931 } 932 933 #endif /* CONFIG_HUGETLB_PAGE */ 934 935 /* 936 * We have 4 cases for pgds and pmds: 937 * (1) invalid (all zeroes) 938 * (2) pointer to next table, as normal; bottom 6 bits == 0 939 * (3) leaf pte for huge page, bottom two bits != 00 940 * (4) hugepd pointer, bottom two bits == 00, next 4 bits indicate size of table 941 * 942 * So long as we atomically load page table pointers we are safe against teardown, 943 * we can follow the address down to the the page and take a ref on it. 944 */ 945 946 pte_t *find_linux_pte_or_hugepte(pgd_t *pgdir, unsigned long ea, unsigned *shift) 947 { 948 pgd_t pgd, *pgdp; 949 pud_t pud, *pudp; 950 pmd_t pmd, *pmdp; 951 pte_t *ret_pte; 952 hugepd_t *hpdp = NULL; 953 unsigned pdshift = PGDIR_SHIFT; 954 955 if (shift) 956 *shift = 0; 957 958 pgdp = pgdir + pgd_index(ea); 959 pgd = ACCESS_ONCE(*pgdp); 960 /* 961 * Always operate on the local stack value. This make sure the 962 * value don't get updated by a parallel THP split/collapse, 963 * page fault or a page unmap. The return pte_t * is still not 964 * stable. So should be checked there for above conditions. 965 */ 966 if (pgd_none(pgd)) 967 return NULL; 968 else if (pgd_huge(pgd)) { 969 ret_pte = (pte_t *) pgdp; 970 goto out; 971 } else if (is_hugepd(__hugepd(pgd_val(pgd)))) 972 hpdp = (hugepd_t *)&pgd; 973 else { 974 /* 975 * Even if we end up with an unmap, the pgtable will not 976 * be freed, because we do an rcu free and here we are 977 * irq disabled 978 */ 979 pdshift = PUD_SHIFT; 980 pudp = pud_offset(&pgd, ea); 981 pud = ACCESS_ONCE(*pudp); 982 983 if (pud_none(pud)) 984 return NULL; 985 else if (pud_huge(pud)) { 986 ret_pte = (pte_t *) pudp; 987 goto out; 988 } else if (is_hugepd(__hugepd(pud_val(pud)))) 989 hpdp = (hugepd_t *)&pud; 990 else { 991 pdshift = PMD_SHIFT; 992 pmdp = pmd_offset(&pud, ea); 993 pmd = ACCESS_ONCE(*pmdp); 994 /* 995 * A hugepage collapse is captured by pmd_none, because 996 * it mark the pmd none and do a hpte invalidate. 997 * 998 * A hugepage split is captured by pmd_trans_splitting 999 * because we mark the pmd trans splitting and do a 1000 * hpte invalidate 1001 * 1002 */ 1003 if (pmd_none(pmd) || pmd_trans_splitting(pmd)) 1004 return NULL; 1005 1006 if (pmd_huge(pmd) || pmd_large(pmd)) { 1007 ret_pte = (pte_t *) pmdp; 1008 goto out; 1009 } else if (is_hugepd(__hugepd(pmd_val(pmd)))) 1010 hpdp = (hugepd_t *)&pmd; 1011 else 1012 return pte_offset_kernel(&pmd, ea); 1013 } 1014 } 1015 if (!hpdp) 1016 return NULL; 1017 1018 ret_pte = hugepte_offset(*hpdp, ea, pdshift); 1019 pdshift = hugepd_shift(*hpdp); 1020 out: 1021 if (shift) 1022 *shift = pdshift; 1023 return ret_pte; 1024 } 1025 EXPORT_SYMBOL_GPL(find_linux_pte_or_hugepte); 1026 1027 int gup_hugepte(pte_t *ptep, unsigned long sz, unsigned long addr, 1028 unsigned long end, int write, struct page **pages, int *nr) 1029 { 1030 unsigned long mask; 1031 unsigned long pte_end; 1032 struct page *head, *page, *tail; 1033 pte_t pte; 1034 int refs; 1035 1036 pte_end = (addr + sz) & ~(sz-1); 1037 if (pte_end < end) 1038 end = pte_end; 1039 1040 pte = ACCESS_ONCE(*ptep); 1041 mask = _PAGE_PRESENT | _PAGE_USER; 1042 if (write) 1043 mask |= _PAGE_RW; 1044 1045 if ((pte_val(pte) & mask) != mask) 1046 return 0; 1047 1048 /* hugepages are never "special" */ 1049 VM_BUG_ON(!pfn_valid(pte_pfn(pte))); 1050 1051 refs = 0; 1052 head = pte_page(pte); 1053 1054 page = head + ((addr & (sz-1)) >> PAGE_SHIFT); 1055 tail = page; 1056 do { 1057 VM_BUG_ON(compound_head(page) != head); 1058 pages[*nr] = page; 1059 (*nr)++; 1060 page++; 1061 refs++; 1062 } while (addr += PAGE_SIZE, addr != end); 1063 1064 if (!page_cache_add_speculative(head, refs)) { 1065 *nr -= refs; 1066 return 0; 1067 } 1068 1069 if (unlikely(pte_val(pte) != pte_val(*ptep))) { 1070 /* Could be optimized better */ 1071 *nr -= refs; 1072 while (refs--) 1073 put_page(head); 1074 return 0; 1075 } 1076 1077 /* 1078 * Any tail page need their mapcount reference taken before we 1079 * return. 1080 */ 1081 while (refs--) { 1082 if (PageTail(tail)) 1083 get_huge_page_tail(tail); 1084 tail++; 1085 } 1086 1087 return 1; 1088 } 1089