arch/powerpc/mm/hugetlbpage.c

   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/moduleparam.h>
  19 #include <linux/swap.h>
  20 #include <linux/swapops.h>
  21 #include <linux/kmemleak.h>
  22 #include <asm/pgtable.h>
  23 #include <asm/pgalloc.h>
  24 #include <asm/tlb.h>
  25 #include <asm/setup.h>
  26 #include <asm/hugetlb.h>
  27 #include <asm/pte-walk.h>
  28
  29 bool hugetlb_disabled = false;
  30
  31 #define hugepd_none(hpd)        (hpd_val(hpd) == 0)
  32
  33 #define PTE_T_ORDER     (__builtin_ffs(sizeof(pte_t)) - __builtin_ffs(sizeof(void *)))
  34
  35 pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr, unsigned long sz)
  36 {
  37         /*
  38          * Only called for hugetlbfs pages, hence can ignore THP and the
  39          * irq disabled walk.
  40          */
  41         return __find_linux_pte(mm->pgd, addr, NULL, NULL);
  42 }
  43
  44 static int __hugepte_alloc(struct mm_struct *mm, hugepd_t *hpdp,
  45                            unsigned long address, unsigned int pdshift,
  46                            unsigned int pshift, spinlock_t *ptl)
  47 {
  48         struct kmem_cache *cachep;
  49         pte_t *new;
  50         int i;
  51         int num_hugepd;
  52
  53         if (pshift >= pdshift) {
  54                 cachep = PGT_CACHE(PTE_T_ORDER);
  55                 num_hugepd = 1 << (pshift - pdshift);
  56         } else if (IS_ENABLED(CONFIG_PPC_8xx)) {
  57                 cachep = PGT_CACHE(PTE_INDEX_SIZE);
  58                 num_hugepd = 1;
  59         } else {
  60                 cachep = PGT_CACHE(pdshift - pshift);
  61                 num_hugepd = 1;
  62         }
  63
  64         if (!cachep) {
  65                 WARN_ONCE(1, "No page table cache created for hugetlb tables");
  66                 return -ENOMEM;
  67         }
  68
  69         new = kmem_cache_alloc(cachep, pgtable_gfp_flags(mm, GFP_KERNEL));
  70
  71         BUG_ON(pshift > HUGEPD_SHIFT_MASK);
  72         BUG_ON((unsigned long)new & HUGEPD_SHIFT_MASK);
  73
  74         if (!new)
  75                 return -ENOMEM;
  76
  77         /*
  78          * Make sure other cpus find the hugepd set only after a
  79          * properly initialized page table is visible to them.
  80          * For more details look for comment in __pte_alloc().
  81          */
  82         smp_wmb();
  83
  84         spin_lock(ptl);
  85         /*
  86          * We have multiple higher-level entries that point to the same
  87          * actual pte location.  Fill in each as we go and backtrack on error.
  88          * We need all of these so the DTLB pgtable walk code can find the
  89          * right higher-level entry without knowing if it's a hugepage or not.
  90          */
  91         for (i = 0; i < num_hugepd; i++, hpdp++) {
  92                 if (unlikely(!hugepd_none(*hpdp)))
  93                         break;
  94                 hugepd_populate(hpdp, new, pshift);
  95         }
  96         /* If we bailed from the for loop early, an error occurred, clean up */
  97         if (i < num_hugepd) {
  98                 for (i = i - 1 ; i >= 0; i--, hpdp--)
  99                         *hpdp = __hugepd(0);
 100                 kmem_cache_free(cachep, new);
 101         } else {
 102                 kmemleak_ignore(new);
 103         }
 104         spin_unlock(ptl);
 105         return 0;
 106 }
 107
 108 /*
 109  * At this point we do the placement change only for BOOK3S 64. This would
 110  * possibly work on other subarchs.
 111  */
 112 pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned long sz)
 113 {
 114         pgd_t *pg;
 115         pud_t *pu;
 116         pmd_t *pm;
 117         hugepd_t *hpdp = NULL;
 118         unsigned pshift = __ffs(sz);
 119         unsigned pdshift = PGDIR_SHIFT;
 120         spinlock_t *ptl;
 121
 122         addr &= ~(sz-1);
 123         pg = pgd_offset(mm, addr);
 124
 125 #ifdef CONFIG_PPC_BOOK3S_64
 126         if (pshift == PGDIR_SHIFT)
 127                 /* 16GB huge page */
 128                 return (pte_t *) pg;
 129         else if (pshift > PUD_SHIFT) {
 130                 /*
 131                  * We need to use hugepd table
 132                  */
 133                 ptl = &mm->page_table_lock;
 134                 hpdp = (hugepd_t *)pg;
 135         } else {
 136                 pdshift = PUD_SHIFT;
 137                 pu = pud_alloc(mm, pg, addr);
 138                 if (!pu)
 139                         return NULL;
 140                 if (pshift == PUD_SHIFT)
 141                         return (pte_t *)pu;
 142                 else if (pshift > PMD_SHIFT) {
 143                         ptl = pud_lockptr(mm, pu);
 144                         hpdp = (hugepd_t *)pu;
 145                 } else {
 146                         pdshift = PMD_SHIFT;
 147                         pm = pmd_alloc(mm, pu, addr);
 148                         if (!pm)
 149                                 return NULL;
 150                         if (pshift == PMD_SHIFT)
 151                                 /* 16MB hugepage */
 152                                 return (pte_t *)pm;
 153                         else {
 154                                 ptl = pmd_lockptr(mm, pm);
 155                                 hpdp = (hugepd_t *)pm;
 156                         }
 157                 }
 158         }
 159 #else
 160         if (pshift >= PGDIR_SHIFT) {
 161                 ptl = &mm->page_table_lock;
 162                 hpdp = (hugepd_t *)pg;
 163         } else {
 164                 pdshift = PUD_SHIFT;
 165                 pu = pud_alloc(mm, pg, addr);
 166                 if (!pu)
 167                         return NULL;
 168                 if (pshift >= PUD_SHIFT) {
 169                         ptl = pud_lockptr(mm, pu);
 170                         hpdp = (hugepd_t *)pu;
 171                 } else {
 172                         pdshift = PMD_SHIFT;
 173                         pm = pmd_alloc(mm, pu, addr);
 174                         if (!pm)
 175                                 return NULL;
 176                         ptl = pmd_lockptr(mm, pm);
 177                         hpdp = (hugepd_t *)pm;
 178                 }
 179         }
 180 #endif
 181         if (!hpdp)
 182                 return NULL;
 183
 184         BUG_ON(!hugepd_none(*hpdp) && !hugepd_ok(*hpdp));
 185
 186         if (hugepd_none(*hpdp) && __hugepte_alloc(mm, hpdp, addr,
 187                                                   pdshift, pshift, ptl))
 188                 return NULL;
 189
 190         return hugepte_offset(*hpdp, addr, pdshift);
 191 }
 192
 193 #ifdef CONFIG_PPC_BOOK3S_64
 194 /*
 195  * Tracks gpages after the device tree is scanned and before the
 196  * huge_boot_pages list is ready on pseries.
 197  */
 198 #define MAX_NUMBER_GPAGES       1024
 199 __initdata static u64 gpage_freearray[MAX_NUMBER_GPAGES];
 200 __initdata static unsigned nr_gpages;
 201
 202 /*
 203  * Build list of addresses of gigantic pages.  This function is used in early
 204  * boot before the buddy allocator is setup.
 205  */
 206 void __init pseries_add_gpage(u64 addr, u64 page_size, unsigned long number_of_pages)
 207 {
 208         if (!addr)
 209                 return;
 210         while (number_of_pages > 0) {
 211                 gpage_freearray[nr_gpages] = addr;
 212                 nr_gpages++;
 213                 number_of_pages--;
 214                 addr += page_size;
 215         }
 216 }
 217
 218 int __init pseries_alloc_bootmem_huge_page(struct hstate *hstate)
 219 {
 220         struct huge_bootmem_page *m;
 221         if (nr_gpages == 0)
 222                 return 0;
 223         m = phys_to_virt(gpage_freearray[--nr_gpages]);
 224         gpage_freearray[nr_gpages] = 0;
 225         list_add(&m->list, &huge_boot_pages);
 226         m->hstate = hstate;
 227         return 1;
 228 }
 229 #endif
 230
 231
 232 int __init alloc_bootmem_huge_page(struct hstate *h)
 233 {
 234
 235 #ifdef CONFIG_PPC_BOOK3S_64
 236         if (firmware_has_feature(FW_FEATURE_LPAR) && !radix_enabled())
 237                 return pseries_alloc_bootmem_huge_page(h);
 238 #endif
 239         return __alloc_bootmem_huge_page(h);
 240 }
 241
 242 #ifndef CONFIG_PPC_BOOK3S_64
 243 #define HUGEPD_FREELIST_SIZE \
 244         ((PAGE_SIZE - sizeof(struct hugepd_freelist)) / sizeof(pte_t))
 245
 246 struct hugepd_freelist {
 247         struct rcu_head rcu;
 248         unsigned int index;
 249         void *ptes[0];
 250 };
 251
 252 static DEFINE_PER_CPU(struct hugepd_freelist *, hugepd_freelist_cur);
 253
 254 static void hugepd_free_rcu_callback(struct rcu_head *head)
 255 {
 256         struct hugepd_freelist *batch =
 257                 container_of(head, struct hugepd_freelist, rcu);
 258         unsigned int i;
 259
 260         for (i = 0; i < batch->index; i++)
 261                 kmem_cache_free(PGT_CACHE(PTE_T_ORDER), batch->ptes[i]);
 262
 263         free_page((unsigned long)batch);
 264 }
 265
 266 static void hugepd_free(struct mmu_gather *tlb, void *hugepte)
 267 {
 268         struct hugepd_freelist **batchp;
 269
 270         batchp = &get_cpu_var(hugepd_freelist_cur);
 271
 272         if (atomic_read(&tlb->mm->mm_users) < 2 ||
 273             mm_is_thread_local(tlb->mm)) {
 274                 kmem_cache_free(PGT_CACHE(PTE_T_ORDER), hugepte);
 275                 put_cpu_var(hugepd_freelist_cur);
 276                 return;
 277         }
 278
 279         if (*batchp == NULL) {
 280                 *batchp = (struct hugepd_freelist *)__get_free_page(GFP_ATOMIC);
 281                 (*batchp)->index = 0;
 282         }
 283
 284         (*batchp)->ptes[(*batchp)->index++] = hugepte;
 285         if ((*batchp)->index == HUGEPD_FREELIST_SIZE) {
 286                 call_rcu(&(*batchp)->rcu, hugepd_free_rcu_callback);
 287                 *batchp = NULL;
 288         }
 289         put_cpu_var(hugepd_freelist_cur);
 290 }
 291 #else
 292 static inline void hugepd_free(struct mmu_gather *tlb, void *hugepte) {}
 293 #endif
 294
 295 static void free_hugepd_range(struct mmu_gather *tlb, hugepd_t *hpdp, int pdshift,
 296                               unsigned long start, unsigned long end,
 297                               unsigned long floor, unsigned long ceiling)
 298 {
 299         pte_t *hugepte = hugepd_page(*hpdp);
 300         int i;
 301
 302         unsigned long pdmask = ~((1UL << pdshift) - 1);
 303         unsigned int num_hugepd = 1;
 304         unsigned int shift = hugepd_shift(*hpdp);
 305
 306         /* Note: On fsl the hpdp may be the first of several */
 307         if (shift > pdshift)
 308                 num_hugepd = 1 << (shift - pdshift);
 309
 310         start &= pdmask;
 311         if (start < floor)
 312                 return;
 313         if (ceiling) {
 314                 ceiling &= pdmask;
 315                 if (! ceiling)
 316                         return;
 317         }
 318         if (end - 1 > ceiling - 1)
 319                 return;
 320
 321         for (i = 0; i < num_hugepd; i++, hpdp++)
 322                 *hpdp = __hugepd(0);
 323
 324         if (shift >= pdshift)
 325                 hugepd_free(tlb, hugepte);
 326         else if (IS_ENABLED(CONFIG_PPC_8xx))
 327                 pgtable_free_tlb(tlb, hugepte,
 328                                  get_hugepd_cache_index(PTE_INDEX_SIZE));
 329         else
 330                 pgtable_free_tlb(tlb, hugepte,
 331                                  get_hugepd_cache_index(pdshift - shift));
 332 }
 333
 334 static void hugetlb_free_pmd_range(struct mmu_gather *tlb, pud_t *pud,
 335                                    unsigned long addr, unsigned long end,
 336                                    unsigned long floor, unsigned long ceiling)
 337 {
 338         pmd_t *pmd;
 339         unsigned long next;
 340         unsigned long start;
 341
 342         start = addr;
 343         do {
 344                 unsigned long more;
 345
 346                 pmd = pmd_offset(pud, addr);
 347                 next = pmd_addr_end(addr, end);
 348                 if (!is_hugepd(__hugepd(pmd_val(*pmd)))) {
 349                         /*
 350                          * if it is not hugepd pointer, we should already find
 351                          * it cleared.
 352                          */
 353                         WARN_ON(!pmd_none_or_clear_bad(pmd));
 354                         continue;
 355                 }
 356                 /*
 357                  * Increment next by the size of the huge mapping since
 358                  * there may be more than one entry at this level for a
 359                  * single hugepage, but all of them point to
 360                  * the same kmem cache that holds the hugepte.
 361                  */
 362                 more = addr + (1 << hugepd_shift(*(hugepd_t *)pmd));
 363                 if (more > next)
 364                         next = more;
 365
 366                 free_hugepd_range(tlb, (hugepd_t *)pmd, PMD_SHIFT,
 367                                   addr, next, floor, ceiling);
 368         } while (addr = next, addr != end);
 369
 370         start &= PUD_MASK;
 371         if (start < floor)
 372                 return;
 373         if (ceiling) {
 374                 ceiling &= PUD_MASK;
 375                 if (!ceiling)
 376                         return;
 377         }
 378         if (end - 1 > ceiling - 1)
 379                 return;
 380
 381         pmd = pmd_offset(pud, start);
 382         pud_clear(pud);
 383         pmd_free_tlb(tlb, pmd, start);
 384         mm_dec_nr_pmds(tlb->mm);
 385 }
 386
 387 static void hugetlb_free_pud_range(struct mmu_gather *tlb, pgd_t *pgd,
 388                                    unsigned long addr, unsigned long end,
 389                                    unsigned long floor, unsigned long ceiling)
 390 {
 391         pud_t *pud;
 392         unsigned long next;
 393         unsigned long start;
 394
 395         start = addr;
 396         do {
 397                 pud = pud_offset(pgd, addr);
 398                 next = pud_addr_end(addr, end);
 399                 if (!is_hugepd(__hugepd(pud_val(*pud)))) {
 400                         if (pud_none_or_clear_bad(pud))
 401                                 continue;
 402                         hugetlb_free_pmd_range(tlb, pud, addr, next, floor,
 403                                                ceiling);
 404                 } else {
 405                         unsigned long more;
 406                         /*
 407                          * Increment next by the size of the huge mapping since
 408                          * there may be more than one entry at this level for a
 409                          * single hugepage, but all of them point to
 410                          * the same kmem cache that holds the hugepte.
 411                          */
 412                         more = addr + (1 << hugepd_shift(*(hugepd_t *)pud));
 413                         if (more > next)
 414                                 next = more;
 415
 416                         free_hugepd_range(tlb, (hugepd_t *)pud, PUD_SHIFT,
 417                                           addr, next, floor, ceiling);
 418                 }
 419         } while (addr = next, addr != end);
 420
 421         start &= PGDIR_MASK;
 422         if (start < floor)
 423                 return;
 424         if (ceiling) {
 425                 ceiling &= PGDIR_MASK;
 426                 if (!ceiling)
 427                         return;
 428         }
 429         if (end - 1 > ceiling - 1)
 430                 return;
 431
 432         pud = pud_offset(pgd, start);
 433         pgd_clear(pgd);
 434         pud_free_tlb(tlb, pud, start);
 435         mm_dec_nr_puds(tlb->mm);
 436 }
 437
 438 /*
 439  * This function frees user-level page tables of a process.
 440  */
 441 void hugetlb_free_pgd_range(struct mmu_gather *tlb,
 442                             unsigned long addr, unsigned long end,
 443                             unsigned long floor, unsigned long ceiling)
 444 {
 445         pgd_t *pgd;
 446         unsigned long next;
 447
 448         /*
 449          * Because there are a number of different possible pagetable
 450          * layouts for hugepage ranges, we limit knowledge of how
 451          * things should be laid out to the allocation path
 452          * (huge_pte_alloc(), above).  Everything else works out the
 453          * structure as it goes from information in the hugepd
 454          * pointers.  That means that we can't here use the
 455          * optimization used in the normal page free_pgd_range(), of
 456          * checking whether we're actually covering a large enough
 457          * range to have to do anything at the top level of the walk
 458          * instead of at the bottom.
 459          *
 460          * To make sense of this, you should probably go read the big
 461          * block comment at the top of the normal free_pgd_range(),
 462          * too.
 463          */
 464
 465         do {
 466                 next = pgd_addr_end(addr, end);
 467                 pgd = pgd_offset(tlb->mm, addr);
 468                 if (!is_hugepd(__hugepd(pgd_val(*pgd)))) {
 469                         if (pgd_none_or_clear_bad(pgd))
 470                                 continue;
 471                         hugetlb_free_pud_range(tlb, pgd, addr, next, floor, ceiling);
 472                 } else {
 473                         unsigned long more;
 474                         /*
 475                          * Increment next by the size of the huge mapping since
 476                          * there may be more than one entry at the pgd level
 477                          * for a single hugepage, but all of them point to the
 478                          * same kmem cache that holds the hugepte.
 479                          */
 480                         more = addr + (1 << hugepd_shift(*(hugepd_t *)pgd));
 481                         if (more > next)
 482                                 next = more;
 483
 484                         free_hugepd_range(tlb, (hugepd_t *)pgd, PGDIR_SHIFT,
 485                                           addr, next, floor, ceiling);
 486                 }
 487         } while (addr = next, addr != end);
 488 }
 489
 490 struct page *follow_huge_pd(struct vm_area_struct *vma,
 491                             unsigned long address, hugepd_t hpd,
 492                             int flags, int pdshift)
 493 {
 494         pte_t *ptep;
 495         spinlock_t *ptl;
 496         struct page *page = NULL;
 497         unsigned long mask;
 498         int shift = hugepd_shift(hpd);
 499         struct mm_struct *mm = vma->vm_mm;
 500
 501 retry:
 502         /*
 503          * hugepage directory entries are protected by mm->page_table_lock
 504          * Use this instead of huge_pte_lockptr
 505          */
 506         ptl = &mm->page_table_lock;
 507         spin_lock(ptl);
 508
 509         ptep = hugepte_offset(hpd, address, pdshift);
 510         if (pte_present(*ptep)) {
 511                 mask = (1UL << shift) - 1;
 512                 page = pte_page(*ptep);
 513                 page += ((address & mask) >> PAGE_SHIFT);
 514                 if (flags & FOLL_GET)
 515                         get_page(page);
 516         } else {
 517                 if (is_hugetlb_entry_migration(*ptep)) {
 518                         spin_unlock(ptl);
 519                         __migration_entry_wait(mm, ptep, ptl);
 520                         goto retry;
 521                 }
 522         }
 523         spin_unlock(ptl);
 524         return page;
 525 }
 526
 527 #ifdef CONFIG_PPC_MM_SLICES
 528 unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 529                                         unsigned long len, unsigned long pgoff,
 530                                         unsigned long flags)
 531 {
 532         struct hstate *hstate = hstate_file(file);
 533         int mmu_psize = shift_to_mmu_psize(huge_page_shift(hstate));
 534
 535 #ifdef CONFIG_PPC_RADIX_MMU
 536         if (radix_enabled())
 537                 return radix__hugetlb_get_unmapped_area(file, addr, len,
 538                                                        pgoff, flags);
 539 #endif
 540         return slice_get_unmapped_area(addr, len, flags, mmu_psize, 1);
 541 }
 542 #endif
 543
 544 unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
 545 {
 546         /* With radix we don't use slice, so derive it from vma*/
 547         if (IS_ENABLED(CONFIG_PPC_MM_SLICES) && !radix_enabled()) {
 548                 unsigned int psize = get_slice_psize(vma->vm_mm, vma->vm_start);
 549
 550                 return 1UL << mmu_psize_to_shift(psize);
 551         }
 552         return vma_kernel_pagesize(vma);
 553 }
 554
 555 static int __init add_huge_page_size(unsigned long long size)
 556 {
 557         int shift = __ffs(size);
 558         int mmu_psize;
 559
 560         /* Check that it is a page size supported by the hardware and
 561          * that it fits within pagetable and slice limits. */
 562         if (size <= PAGE_SIZE || !is_power_of_2(size))
 563                 return -EINVAL;
 564
 565         mmu_psize = check_and_get_huge_psize(shift);
 566         if (mmu_psize < 0)
 567                 return -EINVAL;
 568
 569         BUG_ON(mmu_psize_defs[mmu_psize].shift != shift);
 570
 571         /* Return if huge page size has already been setup */
 572         if (size_to_hstate(size))
 573                 return 0;
 574
 575         hugetlb_add_hstate(shift - PAGE_SHIFT);
 576
 577         return 0;
 578 }
 579
 580 static int __init hugepage_setup_sz(char *str)
 581 {
 582         unsigned long long size;
 583
 584         size = memparse(str, &str);
 585
 586         if (add_huge_page_size(size) != 0) {
 587                 hugetlb_bad_size();
 588                 pr_err("Invalid huge page size specified(%llu)\n", size);
 589         }
 590
 591         return 1;
 592 }
 593 __setup("hugepagesz=", hugepage_setup_sz);
 594
 595 static int __init hugetlbpage_init(void)
 596 {
 597         bool configured = false;
 598         int psize;
 599
 600         if (hugetlb_disabled) {
 601                 pr_info("HugeTLB support is disabled!\n");
 602                 return 0;
 603         }
 604
 605         if (IS_ENABLED(CONFIG_PPC_BOOK3S_64) && !radix_enabled() &&
 606             !mmu_has_feature(MMU_FTR_16M_PAGE))
 607                 return -ENODEV;
 608
 609         for (psize = 0; psize < MMU_PAGE_COUNT; ++psize) {
 610                 unsigned shift;
 611                 unsigned pdshift;
 612
 613                 if (!mmu_psize_defs[psize].shift)
 614                         continue;
 615
 616                 shift = mmu_psize_to_shift(psize);
 617
 618 #ifdef CONFIG_PPC_BOOK3S_64
 619                 if (shift > PGDIR_SHIFT)
 620                         continue;
 621                 else if (shift > PUD_SHIFT)
 622                         pdshift = PGDIR_SHIFT;
 623                 else if (shift > PMD_SHIFT)
 624                         pdshift = PUD_SHIFT;
 625                 else
 626                         pdshift = PMD_SHIFT;
 627 #else
 628                 if (shift < PUD_SHIFT)
 629                         pdshift = PMD_SHIFT;
 630                 else if (shift < PGDIR_SHIFT)
 631                         pdshift = PUD_SHIFT;
 632                 else
 633                         pdshift = PGDIR_SHIFT;
 634 #endif
 635
 636                 if (add_huge_page_size(1ULL << shift) < 0)
 637                         continue;
 638                 /*
 639                  * if we have pdshift and shift value same, we don't
 640                  * use pgt cache for hugepd.
 641                  */
 642                 if (pdshift > shift && IS_ENABLED(CONFIG_PPC_8xx))
 643                         pgtable_cache_add(PTE_INDEX_SIZE);
 644                 else if (pdshift > shift)
 645                         pgtable_cache_add(pdshift - shift);
 646                 else if (IS_ENABLED(CONFIG_PPC_FSL_BOOK3E) || IS_ENABLED(CONFIG_PPC_8xx))
 647                         pgtable_cache_add(PTE_T_ORDER);
 648
 649                 configured = true;
 650         }
 651
 652         if (configured) {
 653                 if (IS_ENABLED(CONFIG_HUGETLB_PAGE_SIZE_VARIABLE))
 654                         hugetlbpage_init_default();
 655         } else
 656                 pr_info("Failed to initialize. Disabling HugeTLB");
 657
 658         return 0;
 659 }
 660
 661 arch_initcall(hugetlbpage_init);
 662
 663 void flush_dcache_icache_hugepage(struct page *page)
 664 {
 665         int i;
 666         void *start;
 667
 668         BUG_ON(!PageCompound(page));
 669
 670         for (i = 0; i < compound_nr(page); i++) {
 671                 if (!PageHighMem(page)) {
 672                         __flush_dcache_icache(page_address(page+i));
 673                 } else {
 674                         start = kmap_atomic(page+i);
 675                         __flush_dcache_icache(start);
 676                         kunmap_atomic(start);
 677                 }
 678         }
 679 }