root/arch/powerpc/mm/hugetlbpage.c

DEFINITIONS

1. huge_pte_offset
2. __hugepte_alloc
3. huge_pte_alloc
4. pseries_add_gpage
5. pseries_alloc_bootmem_huge_page
6. alloc_bootmem_huge_page
7. hugepd_free_rcu_callback
8. hugepd_free
9. hugepd_free
10. free_hugepd_range
11. hugetlb_free_pmd_range
12. hugetlb_free_pud_range
13. hugetlb_free_pgd_range
14. follow_huge_pd
15. hugetlb_get_unmapped_area
16. vma_mmu_pagesize
17. add_huge_page_size
18. hugepage_setup_sz
19. hugetlbpage_init
20. flush_dcache_icache_hugepage

   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                 new = NULL;
  57         } else if (IS_ENABLED(CONFIG_PPC_8xx)) {
  58                 cachep = NULL;
  59                 num_hugepd = 1;
  60                 new = pte_alloc_one(mm);
  61         } else {
  62                 cachep = PGT_CACHE(pdshift - pshift);
  63                 num_hugepd = 1;
  64                 new = NULL;
  65         }
  66 
  67         if (!cachep && !new) {
  68                 WARN_ONCE(1, "No page table cache created for hugetlb tables");
  69                 return -ENOMEM;
  70         }
  71 
  72         if (cachep)
  73                 new = kmem_cache_alloc(cachep, pgtable_gfp_flags(mm, GFP_KERNEL));
  74 
  75         BUG_ON(pshift > HUGEPD_SHIFT_MASK);
  76         BUG_ON((unsigned long)new & HUGEPD_SHIFT_MASK);
  77 
  78         if (!new)
  79                 return -ENOMEM;
  80 
  81         /*
  82          * Make sure other cpus find the hugepd set only after a
  83          * properly initialized page table is visible to them.
  84          * For more details look for comment in __pte_alloc().
  85          */
  86         smp_wmb();
  87 
  88         spin_lock(ptl);
  89         /*
  90          * We have multiple higher-level entries that point to the same
  91          * actual pte location.  Fill in each as we go and backtrack on error.
  92          * We need all of these so the DTLB pgtable walk code can find the
  93          * right higher-level entry without knowing if it's a hugepage or not.
  94          */
  95         for (i = 0; i < num_hugepd; i++, hpdp++) {
  96                 if (unlikely(!hugepd_none(*hpdp)))
  97                         break;
  98                 hugepd_populate(hpdp, new, pshift);
  99         }
 100         /* If we bailed from the for loop early, an error occurred, clean up */
 101         if (i < num_hugepd) {
 102                 for (i = i - 1 ; i >= 0; i--, hpdp--)
 103                         *hpdp = __hugepd(0);
 104                 if (cachep)
 105                         kmem_cache_free(cachep, new);
 106                 else
 107                         pte_free(mm, new);
 108         } else {
 109                 kmemleak_ignore(new);
 110         }
 111         spin_unlock(ptl);
 112         return 0;
 113 }
 114 
 115 /*
 116  * At this point we do the placement change only for BOOK3S 64. This would
 117  * possibly work on other subarchs.
 118  */
 119 pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned long sz)
 120 {
 121         pgd_t *pg;
 122         pud_t *pu;
 123         pmd_t *pm;
 124         hugepd_t *hpdp = NULL;
 125         unsigned pshift = __ffs(sz);
 126         unsigned pdshift = PGDIR_SHIFT;
 127         spinlock_t *ptl;
 128 
 129         addr &= ~(sz-1);
 130         pg = pgd_offset(mm, addr);
 131 
 132 #ifdef CONFIG_PPC_BOOK3S_64
 133         if (pshift == PGDIR_SHIFT)
 134                 /* 16GB huge page */
 135                 return (pte_t *) pg;
 136         else if (pshift > PUD_SHIFT) {
 137                 /*
 138                  * We need to use hugepd table
 139                  */
 140                 ptl = &mm->page_table_lock;
 141                 hpdp = (hugepd_t *)pg;
 142         } else {
 143                 pdshift = PUD_SHIFT;
 144                 pu = pud_alloc(mm, pg, addr);
 145                 if (!pu)
 146                         return NULL;
 147                 if (pshift == PUD_SHIFT)
 148                         return (pte_t *)pu;
 149                 else if (pshift > PMD_SHIFT) {
 150                         ptl = pud_lockptr(mm, pu);
 151                         hpdp = (hugepd_t *)pu;
 152                 } else {
 153                         pdshift = PMD_SHIFT;
 154                         pm = pmd_alloc(mm, pu, addr);
 155                         if (!pm)
 156                                 return NULL;
 157                         if (pshift == PMD_SHIFT)
 158                                 /* 16MB hugepage */
 159                                 return (pte_t *)pm;
 160                         else {
 161                                 ptl = pmd_lockptr(mm, pm);
 162                                 hpdp = (hugepd_t *)pm;
 163                         }
 164                 }
 165         }
 166 #else
 167         if (pshift >= PGDIR_SHIFT) {
 168                 ptl = &mm->page_table_lock;
 169                 hpdp = (hugepd_t *)pg;
 170         } else {
 171                 pdshift = PUD_SHIFT;
 172                 pu = pud_alloc(mm, pg, addr);
 173                 if (!pu)
 174                         return NULL;
 175                 if (pshift >= PUD_SHIFT) {
 176                         ptl = pud_lockptr(mm, pu);
 177                         hpdp = (hugepd_t *)pu;
 178                 } else {
 179                         pdshift = PMD_SHIFT;
 180                         pm = pmd_alloc(mm, pu, addr);
 181                         if (!pm)
 182                                 return NULL;
 183                         ptl = pmd_lockptr(mm, pm);
 184                         hpdp = (hugepd_t *)pm;
 185                 }
 186         }
 187 #endif
 188         if (!hpdp)
 189                 return NULL;
 190 
 191         BUG_ON(!hugepd_none(*hpdp) && !hugepd_ok(*hpdp));
 192 
 193         if (hugepd_none(*hpdp) && __hugepte_alloc(mm, hpdp, addr,
 194                                                   pdshift, pshift, ptl))
 195                 return NULL;
 196 
 197         return hugepte_offset(*hpdp, addr, pdshift);
 198 }
 199 
 200 #ifdef CONFIG_PPC_BOOK3S_64
 201 /*
 202  * Tracks gpages after the device tree is scanned and before the
 203  * huge_boot_pages list is ready on pseries.
 204  */
 205 #define MAX_NUMBER_GPAGES       1024
 206 __initdata static u64 gpage_freearray[MAX_NUMBER_GPAGES];
 207 __initdata static unsigned nr_gpages;
 208 
 209 /*
 210  * Build list of addresses of gigantic pages.  This function is used in early
 211  * boot before the buddy allocator is setup.
 212  */
 213 void __init pseries_add_gpage(u64 addr, u64 page_size, unsigned long number_of_pages)
 214 {
 215         if (!addr)
 216                 return;
 217         while (number_of_pages > 0) {
 218                 gpage_freearray[nr_gpages] = addr;
 219                 nr_gpages++;
 220                 number_of_pages--;
 221                 addr += page_size;
 222         }
 223 }
 224 
 225 int __init pseries_alloc_bootmem_huge_page(struct hstate *hstate)
 226 {
 227         struct huge_bootmem_page *m;
 228         if (nr_gpages == 0)
 229                 return 0;
 230         m = phys_to_virt(gpage_freearray[--nr_gpages]);
 231         gpage_freearray[nr_gpages] = 0;
 232         list_add(&m->list, &huge_boot_pages);
 233         m->hstate = hstate;
 234         return 1;
 235 }
 236 #endif
 237 
 238 
 239 int __init alloc_bootmem_huge_page(struct hstate *h)
 240 {
 241 
 242 #ifdef CONFIG_PPC_BOOK3S_64
 243         if (firmware_has_feature(FW_FEATURE_LPAR) && !radix_enabled())
 244                 return pseries_alloc_bootmem_huge_page(h);
 245 #endif
 246         return __alloc_bootmem_huge_page(h);
 247 }
 248 
 249 #ifndef CONFIG_PPC_BOOK3S_64
 250 #define HUGEPD_FREELIST_SIZE \
 251         ((PAGE_SIZE - sizeof(struct hugepd_freelist)) / sizeof(pte_t))
 252 
 253 struct hugepd_freelist {
 254         struct rcu_head rcu;
 255         unsigned int index;
 256         void *ptes[0];
 257 };
 258 
 259 static DEFINE_PER_CPU(struct hugepd_freelist *, hugepd_freelist_cur);
 260 
 261 static void hugepd_free_rcu_callback(struct rcu_head *head)
 262 {
 263         struct hugepd_freelist *batch =
 264                 container_of(head, struct hugepd_freelist, rcu);
 265         unsigned int i;
 266 
 267         for (i = 0; i < batch->index; i++)
 268                 kmem_cache_free(PGT_CACHE(PTE_T_ORDER), batch->ptes[i]);
 269 
 270         free_page((unsigned long)batch);
 271 }
 272 
 273 static void hugepd_free(struct mmu_gather *tlb, void *hugepte)
 274 {
 275         struct hugepd_freelist **batchp;
 276 
 277         batchp = &get_cpu_var(hugepd_freelist_cur);
 278 
 279         if (atomic_read(&tlb->mm->mm_users) < 2 ||
 280             mm_is_thread_local(tlb->mm)) {
 281                 kmem_cache_free(PGT_CACHE(PTE_T_ORDER), hugepte);
 282                 put_cpu_var(hugepd_freelist_cur);
 283                 return;
 284         }
 285 
 286         if (*batchp == NULL) {
 287                 *batchp = (struct hugepd_freelist *)__get_free_page(GFP_ATOMIC);
 288                 (*batchp)->index = 0;
 289         }
 290 
 291         (*batchp)->ptes[(*batchp)->index++] = hugepte;
 292         if ((*batchp)->index == HUGEPD_FREELIST_SIZE) {
 293                 call_rcu(&(*batchp)->rcu, hugepd_free_rcu_callback);
 294                 *batchp = NULL;
 295         }
 296         put_cpu_var(hugepd_freelist_cur);
 297 }
 298 #else
 299 static inline void hugepd_free(struct mmu_gather *tlb, void *hugepte) {}
 300 #endif
 301 
 302 static void free_hugepd_range(struct mmu_gather *tlb, hugepd_t *hpdp, int pdshift,
 303                               unsigned long start, unsigned long end,
 304                               unsigned long floor, unsigned long ceiling)
 305 {
 306         pte_t *hugepte = hugepd_page(*hpdp);
 307         int i;
 308 
 309         unsigned long pdmask = ~((1UL << pdshift) - 1);
 310         unsigned int num_hugepd = 1;
 311         unsigned int shift = hugepd_shift(*hpdp);
 312 
 313         /* Note: On fsl the hpdp may be the first of several */
 314         if (shift > pdshift)
 315                 num_hugepd = 1 << (shift - pdshift);
 316 
 317         start &= pdmask;
 318         if (start < floor)
 319                 return;
 320         if (ceiling) {
 321                 ceiling &= pdmask;
 322                 if (! ceiling)
 323                         return;
 324         }
 325         if (end - 1 > ceiling - 1)
 326                 return;
 327 
 328         for (i = 0; i < num_hugepd; i++, hpdp++)
 329                 *hpdp = __hugepd(0);
 330 
 331         if (shift >= pdshift)
 332                 hugepd_free(tlb, hugepte);
 333         else if (IS_ENABLED(CONFIG_PPC_8xx))
 334                 pgtable_free_tlb(tlb, hugepte, 0);
 335         else
 336                 pgtable_free_tlb(tlb, hugepte,
 337                                  get_hugepd_cache_index(pdshift - shift));
 338 }
 339 
 340 static void hugetlb_free_pmd_range(struct mmu_gather *tlb, pud_t *pud,
 341                                    unsigned long addr, unsigned long end,
 342                                    unsigned long floor, unsigned long ceiling)
 343 {
 344         pmd_t *pmd;
 345         unsigned long next;
 346         unsigned long start;
 347 
 348         start = addr;
 349         do {
 350                 unsigned long more;
 351 
 352                 pmd = pmd_offset(pud, addr);
 353                 next = pmd_addr_end(addr, end);
 354                 if (!is_hugepd(__hugepd(pmd_val(*pmd)))) {
 355                         /*
 356                          * if it is not hugepd pointer, we should already find
 357                          * it cleared.
 358                          */
 359                         WARN_ON(!pmd_none_or_clear_bad(pmd));
 360                         continue;
 361                 }
 362                 /*
 363                  * Increment next by the size of the huge mapping since
 364                  * there may be more than one entry at this level for a
 365                  * single hugepage, but all of them point to
 366                  * the same kmem cache that holds the hugepte.
 367                  */
 368                 more = addr + (1 << hugepd_shift(*(hugepd_t *)pmd));
 369                 if (more > next)
 370                         next = more;
 371 
 372                 free_hugepd_range(tlb, (hugepd_t *)pmd, PMD_SHIFT,
 373                                   addr, next, floor, ceiling);
 374         } while (addr = next, addr != end);
 375 
 376         start &= PUD_MASK;
 377         if (start < floor)
 378                 return;
 379         if (ceiling) {
 380                 ceiling &= PUD_MASK;
 381                 if (!ceiling)
 382                         return;
 383         }
 384         if (end - 1 > ceiling - 1)
 385                 return;
 386 
 387         pmd = pmd_offset(pud, start);
 388         pud_clear(pud);
 389         pmd_free_tlb(tlb, pmd, start);
 390         mm_dec_nr_pmds(tlb->mm);
 391 }
 392 
 393 static void hugetlb_free_pud_range(struct mmu_gather *tlb, pgd_t *pgd,
 394                                    unsigned long addr, unsigned long end,
 395                                    unsigned long floor, unsigned long ceiling)
 396 {
 397         pud_t *pud;
 398         unsigned long next;
 399         unsigned long start;
 400 
 401         start = addr;
 402         do {
 403                 pud = pud_offset(pgd, addr);
 404                 next = pud_addr_end(addr, end);
 405                 if (!is_hugepd(__hugepd(pud_val(*pud)))) {
 406                         if (pud_none_or_clear_bad(pud))
 407                                 continue;
 408                         hugetlb_free_pmd_range(tlb, pud, addr, next, floor,
 409                                                ceiling);
 410                 } else {
 411                         unsigned long more;
 412                         /*
 413                          * Increment next by the size of the huge mapping since
 414                          * there may be more than one entry at this level for a
 415                          * single hugepage, but all of them point to
 416                          * the same kmem cache that holds the hugepte.
 417                          */
 418                         more = addr + (1 << hugepd_shift(*(hugepd_t *)pud));
 419                         if (more > next)
 420                                 next = more;
 421 
 422                         free_hugepd_range(tlb, (hugepd_t *)pud, PUD_SHIFT,
 423                                           addr, next, floor, ceiling);
 424                 }
 425         } while (addr = next, addr != end);
 426 
 427         start &= PGDIR_MASK;
 428         if (start < floor)
 429                 return;
 430         if (ceiling) {
 431                 ceiling &= PGDIR_MASK;
 432                 if (!ceiling)
 433                         return;
 434         }
 435         if (end - 1 > ceiling - 1)
 436                 return;
 437 
 438         pud = pud_offset(pgd, start);
 439         pgd_clear(pgd);
 440         pud_free_tlb(tlb, pud, start);
 441         mm_dec_nr_puds(tlb->mm);
 442 }
 443 
 444 /*
 445  * This function frees user-level page tables of a process.
 446  */
 447 void hugetlb_free_pgd_range(struct mmu_gather *tlb,
 448                             unsigned long addr, unsigned long end,
 449                             unsigned long floor, unsigned long ceiling)
 450 {
 451         pgd_t *pgd;
 452         unsigned long next;
 453 
 454         /*
 455          * Because there are a number of different possible pagetable
 456          * layouts for hugepage ranges, we limit knowledge of how
 457          * things should be laid out to the allocation path
 458          * (huge_pte_alloc(), above).  Everything else works out the
 459          * structure as it goes from information in the hugepd
 460          * pointers.  That means that we can't here use the
 461          * optimization used in the normal page free_pgd_range(), of
 462          * checking whether we're actually covering a large enough
 463          * range to have to do anything at the top level of the walk
 464          * instead of at the bottom.
 465          *
 466          * To make sense of this, you should probably go read the big
 467          * block comment at the top of the normal free_pgd_range(),
 468          * too.
 469          */
 470 
 471         do {
 472                 next = pgd_addr_end(addr, end);
 473                 pgd = pgd_offset(tlb->mm, addr);
 474                 if (!is_hugepd(__hugepd(pgd_val(*pgd)))) {
 475                         if (pgd_none_or_clear_bad(pgd))
 476                                 continue;
 477                         hugetlb_free_pud_range(tlb, pgd, addr, next, floor, ceiling);
 478                 } else {
 479                         unsigned long more;
 480                         /*
 481                          * Increment next by the size of the huge mapping since
 482                          * there may be more than one entry at the pgd level
 483                          * for a single hugepage, but all of them point to the
 484                          * same kmem cache that holds the hugepte.
 485                          */
 486                         more = addr + (1 << hugepd_shift(*(hugepd_t *)pgd));
 487                         if (more > next)
 488                                 next = more;
 489 
 490                         free_hugepd_range(tlb, (hugepd_t *)pgd, PGDIR_SHIFT,
 491                                           addr, next, floor, ceiling);
 492                 }
 493         } while (addr = next, addr != end);
 494 }
 495 
 496 struct page *follow_huge_pd(struct vm_area_struct *vma,
 497                             unsigned long address, hugepd_t hpd,
 498                             int flags, int pdshift)
 499 {
 500         pte_t *ptep;
 501         spinlock_t *ptl;
 502         struct page *page = NULL;
 503         unsigned long mask;
 504         int shift = hugepd_shift(hpd);
 505         struct mm_struct *mm = vma->vm_mm;
 506 
 507 retry:
 508         /*
 509          * hugepage directory entries are protected by mm->page_table_lock
 510          * Use this instead of huge_pte_lockptr
 511          */
 512         ptl = &mm->page_table_lock;
 513         spin_lock(ptl);
 514 
 515         ptep = hugepte_offset(hpd, address, pdshift);
 516         if (pte_present(*ptep)) {
 517                 mask = (1UL << shift) - 1;
 518                 page = pte_page(*ptep);
 519                 page += ((address & mask) >> PAGE_SHIFT);
 520                 if (flags & FOLL_GET)
 521                         get_page(page);
 522         } else {
 523                 if (is_hugetlb_entry_migration(*ptep)) {
 524                         spin_unlock(ptl);
 525                         __migration_entry_wait(mm, ptep, ptl);
 526                         goto retry;
 527                 }
 528         }
 529         spin_unlock(ptl);
 530         return page;
 531 }
 532 
 533 #ifdef CONFIG_PPC_MM_SLICES
 534 unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 535                                         unsigned long len, unsigned long pgoff,
 536                                         unsigned long flags)
 537 {
 538         struct hstate *hstate = hstate_file(file);
 539         int mmu_psize = shift_to_mmu_psize(huge_page_shift(hstate));
 540 
 541 #ifdef CONFIG_PPC_RADIX_MMU
 542         if (radix_enabled())
 543                 return radix__hugetlb_get_unmapped_area(file, addr, len,
 544                                                        pgoff, flags);
 545 #endif
 546         return slice_get_unmapped_area(addr, len, flags, mmu_psize, 1);
 547 }
 548 #endif
 549 
 550 unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
 551 {
 552         /* With radix we don't use slice, so derive it from vma*/
 553         if (IS_ENABLED(CONFIG_PPC_MM_SLICES) && !radix_enabled()) {
 554                 unsigned int psize = get_slice_psize(vma->vm_mm, vma->vm_start);
 555 
 556                 return 1UL << mmu_psize_to_shift(psize);
 557         }
 558         return vma_kernel_pagesize(vma);
 559 }
 560 
 561 static int __init add_huge_page_size(unsigned long long size)
 562 {
 563         int shift = __ffs(size);
 564         int mmu_psize;
 565 
 566         /* Check that it is a page size supported by the hardware and
 567          * that it fits within pagetable and slice limits. */
 568         if (size <= PAGE_SIZE || !is_power_of_2(size))
 569                 return -EINVAL;
 570 
 571         mmu_psize = check_and_get_huge_psize(shift);
 572         if (mmu_psize < 0)
 573                 return -EINVAL;
 574 
 575         BUG_ON(mmu_psize_defs[mmu_psize].shift != shift);
 576 
 577         /* Return if huge page size has already been setup */
 578         if (size_to_hstate(size))
 579                 return 0;
 580 
 581         hugetlb_add_hstate(shift - PAGE_SHIFT);
 582 
 583         return 0;
 584 }
 585 
 586 static int __init hugepage_setup_sz(char *str)
 587 {
 588         unsigned long long size;
 589 
 590         size = memparse(str, &str);
 591 
 592         if (add_huge_page_size(size) != 0) {
 593                 hugetlb_bad_size();
 594                 pr_err("Invalid huge page size specified(%llu)\n", size);
 595         }
 596 
 597         return 1;
 598 }
 599 __setup("hugepagesz=", hugepage_setup_sz);
 600 
 601 static int __init hugetlbpage_init(void)
 602 {
 603         bool configured = false;
 604         int psize;
 605 
 606         if (hugetlb_disabled) {
 607                 pr_info("HugeTLB support is disabled!\n");
 608                 return 0;
 609         }
 610 
 611         if (IS_ENABLED(CONFIG_PPC_BOOK3S_64) && !radix_enabled() &&
 612             !mmu_has_feature(MMU_FTR_16M_PAGE))
 613                 return -ENODEV;
 614 
 615         for (psize = 0; psize < MMU_PAGE_COUNT; ++psize) {
 616                 unsigned shift;
 617                 unsigned pdshift;
 618 
 619                 if (!mmu_psize_defs[psize].shift)
 620                         continue;
 621 
 622                 shift = mmu_psize_to_shift(psize);
 623 
 624 #ifdef CONFIG_PPC_BOOK3S_64
 625                 if (shift > PGDIR_SHIFT)
 626                         continue;
 627                 else if (shift > PUD_SHIFT)
 628                         pdshift = PGDIR_SHIFT;
 629                 else if (shift > PMD_SHIFT)
 630                         pdshift = PUD_SHIFT;
 631                 else
 632                         pdshift = PMD_SHIFT;
 633 #else
 634                 if (shift < PUD_SHIFT)
 635                         pdshift = PMD_SHIFT;
 636                 else if (shift < PGDIR_SHIFT)
 637                         pdshift = PUD_SHIFT;
 638                 else
 639                         pdshift = PGDIR_SHIFT;
 640 #endif
 641 
 642                 if (add_huge_page_size(1ULL << shift) < 0)
 643                         continue;
 644                 /*
 645                  * if we have pdshift and shift value same, we don't
 646                  * use pgt cache for hugepd.
 647                  */
 648                 if (pdshift > shift) {
 649                         if (!IS_ENABLED(CONFIG_PPC_8xx))
 650                                 pgtable_cache_add(pdshift - shift);
 651                 } else if (IS_ENABLED(CONFIG_PPC_FSL_BOOK3E) ||
 652                            IS_ENABLED(CONFIG_PPC_8xx)) {
 653                         pgtable_cache_add(PTE_T_ORDER);
 654                 }
 655 
 656                 configured = true;
 657         }
 658 
 659         if (configured) {
 660                 if (IS_ENABLED(CONFIG_HUGETLB_PAGE_SIZE_VARIABLE))
 661                         hugetlbpage_init_default();
 662         } else
 663                 pr_info("Failed to initialize. Disabling HugeTLB");
 664 
 665         return 0;
 666 }
 667 
 668 arch_initcall(hugetlbpage_init);
 669 
 670 void flush_dcache_icache_hugepage(struct page *page)
 671 {
 672         int i;
 673         void *start;
 674 
 675         BUG_ON(!PageCompound(page));
 676 
 677         for (i = 0; i < compound_nr(page); i++) {
 678                 if (!PageHighMem(page)) {
 679                         __flush_dcache_icache(page_address(page+i));
 680                 } else {
 681                         start = kmap_atomic(page+i);
 682                         __flush_dcache_icache(start);
 683                         kunmap_atomic(start);
 684                 }
 685         }
 686 }