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/pgalloc.h>
  23 #include <asm/tlb.h>
  24 #include <asm/setup.h>
  25 #include <asm/hugetlb.h>
  26 #include <asm/pte-walk.h>
  27
  28 bool hugetlb_disabled = false;
  29
  30 #define hugepd_none(hpd)        (hpd_val(hpd) == 0)
  31
  32 #define PTE_T_ORDER     (__builtin_ffs(sizeof(pte_basic_t)) - \
  33                          __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 {
  57                 cachep = PGT_CACHE(pdshift - pshift);
  58                 num_hugepd = 1;
  59         }
  60
  61         if (!cachep) {
  62                 WARN_ONCE(1, "No page table cache created for hugetlb tables");
  63                 return -ENOMEM;
  64         }
  65
  66         new = kmem_cache_alloc(cachep, pgtable_gfp_flags(mm, GFP_KERNEL));
  67
  68         BUG_ON(pshift > HUGEPD_SHIFT_MASK);
  69         BUG_ON((unsigned long)new & HUGEPD_SHIFT_MASK);
  70
  71         if (!new)
  72                 return -ENOMEM;
  73
  74         /*
  75          * Make sure other cpus find the hugepd set only after a
  76          * properly initialized page table is visible to them.
  77          * For more details look for comment in __pte_alloc().
  78          */
  79         smp_wmb();
  80
  81         spin_lock(ptl);
  82         /*
  83          * We have multiple higher-level entries that point to the same
  84          * actual pte location.  Fill in each as we go and backtrack on error.
  85          * We need all of these so the DTLB pgtable walk code can find the
  86          * right higher-level entry without knowing if it's a hugepage or not.
  87          */
  88         for (i = 0; i < num_hugepd; i++, hpdp++) {
  89                 if (unlikely(!hugepd_none(*hpdp)))
  90                         break;
  91                 hugepd_populate(hpdp, new, pshift);
  92         }
  93         /* If we bailed from the for loop early, an error occurred, clean up */
  94         if (i < num_hugepd) {
  95                 for (i = i - 1 ; i >= 0; i--, hpdp--)
  96                         *hpdp = __hugepd(0);
  97                 kmem_cache_free(cachep, new);
  98         } else {
  99                 kmemleak_ignore(new);
 100         }
 101         spin_unlock(ptl);
 102         return 0;
 103 }
 104
 105 /*
 106  * At this point we do the placement change only for BOOK3S 64. This would
 107  * possibly work on other subarchs.
 108  */
 109 pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr, unsigned long sz)
 110 {
 111         pgd_t *pg;
 112         p4d_t *p4;
 113         pud_t *pu;
 114         pmd_t *pm;
 115         hugepd_t *hpdp = NULL;
 116         unsigned pshift = __ffs(sz);
 117         unsigned pdshift = PGDIR_SHIFT;
 118         spinlock_t *ptl;
 119
 120         addr &= ~(sz-1);
 121         pg = pgd_offset(mm, addr);
 122         p4 = p4d_offset(pg, addr);
 123
 124 #ifdef CONFIG_PPC_BOOK3S_64
 125         if (pshift == PGDIR_SHIFT)
 126                 /* 16GB huge page */
 127                 return (pte_t *) p4;
 128         else if (pshift > PUD_SHIFT) {
 129                 /*
 130                  * We need to use hugepd table
 131                  */
 132                 ptl = &mm->page_table_lock;
 133                 hpdp = (hugepd_t *)p4;
 134         } else {
 135                 pdshift = PUD_SHIFT;
 136                 pu = pud_alloc(mm, p4, addr);
 137                 if (!pu)
 138                         return NULL;
 139                 if (pshift == PUD_SHIFT)
 140                         return (pte_t *)pu;
 141                 else if (pshift > PMD_SHIFT) {
 142                         ptl = pud_lockptr(mm, pu);
 143                         hpdp = (hugepd_t *)pu;
 144                 } else {
 145                         pdshift = PMD_SHIFT;
 146                         pm = pmd_alloc(mm, pu, addr);
 147                         if (!pm)
 148                                 return NULL;
 149                         if (pshift == PMD_SHIFT)
 150                                 /* 16MB hugepage */
 151                                 return (pte_t *)pm;
 152                         else {
 153                                 ptl = pmd_lockptr(mm, pm);
 154                                 hpdp = (hugepd_t *)pm;
 155                         }
 156                 }
 157         }
 158 #else
 159         if (pshift >= PGDIR_SHIFT) {
 160                 ptl = &mm->page_table_lock;
 161                 hpdp = (hugepd_t *)p4;
 162         } else {
 163                 pdshift = PUD_SHIFT;
 164                 pu = pud_alloc(mm, p4, addr);
 165                 if (!pu)
 166                         return NULL;
 167                 if (pshift >= PUD_SHIFT) {
 168                         ptl = pud_lockptr(mm, pu);
 169                         hpdp = (hugepd_t *)pu;
 170                 } else {
 171                         pdshift = PMD_SHIFT;
 172                         pm = pmd_alloc(mm, pu, addr);
 173                         if (!pm)
 174                                 return NULL;
 175                         ptl = pmd_lockptr(mm, pm);
 176                         hpdp = (hugepd_t *)pm;
 177                 }
 178         }
 179 #endif
 180         if (!hpdp)
 181                 return NULL;
 182
 183         if (IS_ENABLED(CONFIG_PPC_8xx) && pshift < PMD_SHIFT)
 184                 return pte_alloc_map(mm, (pmd_t *)hpdp, addr);
 185
 186         BUG_ON(!hugepd_none(*hpdp) && !hugepd_ok(*hpdp));
 187
 188         if (hugepd_none(*hpdp) && __hugepte_alloc(mm, hpdp, addr,
 189                                                   pdshift, pshift, ptl))
 190                 return NULL;
 191
 192         return hugepte_offset(*hpdp, addr, pdshift);
 193 }
 194
 195 #ifdef CONFIG_PPC_BOOK3S_64
 196 /*
 197  * Tracks gpages after the device tree is scanned and before the
 198  * huge_boot_pages list is ready on pseries.
 199  */
 200 #define MAX_NUMBER_GPAGES       1024
 201 __initdata static u64 gpage_freearray[MAX_NUMBER_GPAGES];
 202 __initdata static unsigned nr_gpages;
 203
 204 /*
 205  * Build list of addresses of gigantic pages.  This function is used in early
 206  * boot before the buddy allocator is setup.
 207  */
 208 void __init pseries_add_gpage(u64 addr, u64 page_size, unsigned long number_of_pages)
 209 {
 210         if (!addr)
 211                 return;
 212         while (number_of_pages > 0) {
 213                 gpage_freearray[nr_gpages] = addr;
 214                 nr_gpages++;
 215                 number_of_pages--;
 216                 addr += page_size;
 217         }
 218 }
 219
 220 int __init pseries_alloc_bootmem_huge_page(struct hstate *hstate)
 221 {
 222         struct huge_bootmem_page *m;
 223         if (nr_gpages == 0)
 224                 return 0;
 225         m = phys_to_virt(gpage_freearray[--nr_gpages]);
 226         gpage_freearray[nr_gpages] = 0;
 227         list_add(&m->list, &huge_boot_pages);
 228         m->hstate = hstate;
 229         return 1;
 230 }
 231 #endif
 232
 233
 234 int __init alloc_bootmem_huge_page(struct hstate *h)
 235 {
 236
 237 #ifdef CONFIG_PPC_BOOK3S_64
 238         if (firmware_has_feature(FW_FEATURE_LPAR) && !radix_enabled())
 239                 return pseries_alloc_bootmem_huge_page(h);
 240 #endif
 241         return __alloc_bootmem_huge_page(h);
 242 }
 243
 244 #ifndef CONFIG_PPC_BOOK3S_64
 245 #define HUGEPD_FREELIST_SIZE \
 246         ((PAGE_SIZE - sizeof(struct hugepd_freelist)) / sizeof(pte_t))
 247
 248 struct hugepd_freelist {
 249         struct rcu_head rcu;
 250         unsigned int index;
 251         void *ptes[];
 252 };
 253
 254 static DEFINE_PER_CPU(struct hugepd_freelist *, hugepd_freelist_cur);
 255
 256 static void hugepd_free_rcu_callback(struct rcu_head *head)
 257 {
 258         struct hugepd_freelist *batch =
 259                 container_of(head, struct hugepd_freelist, rcu);
 260         unsigned int i;
 261
 262         for (i = 0; i < batch->index; i++)
 263                 kmem_cache_free(PGT_CACHE(PTE_T_ORDER), batch->ptes[i]);
 264
 265         free_page((unsigned long)batch);
 266 }
 267
 268 static void hugepd_free(struct mmu_gather *tlb, void *hugepte)
 269 {
 270         struct hugepd_freelist **batchp;
 271
 272         batchp = &get_cpu_var(hugepd_freelist_cur);
 273
 274         if (atomic_read(&tlb->mm->mm_users) < 2 ||
 275             mm_is_thread_local(tlb->mm)) {
 276                 kmem_cache_free(PGT_CACHE(PTE_T_ORDER), hugepte);
 277                 put_cpu_var(hugepd_freelist_cur);
 278                 return;
 279         }
 280
 281         if (*batchp == NULL) {
 282                 *batchp = (struct hugepd_freelist *)__get_free_page(GFP_ATOMIC);
 283                 (*batchp)->index = 0;
 284         }
 285
 286         (*batchp)->ptes[(*batchp)->index++] = hugepte;
 287         if ((*batchp)->index == HUGEPD_FREELIST_SIZE) {
 288                 call_rcu(&(*batchp)->rcu, hugepd_free_rcu_callback);
 289                 *batchp = NULL;
 290         }
 291         put_cpu_var(hugepd_freelist_cur);
 292 }
 293 #else
 294 static inline void hugepd_free(struct mmu_gather *tlb, void *hugepte) {}
 295 #endif
 296
 297 static void free_hugepd_range(struct mmu_gather *tlb, hugepd_t *hpdp, int pdshift,
 298                               unsigned long start, unsigned long end,
 299                               unsigned long floor, unsigned long ceiling)
 300 {
 301         pte_t *hugepte = hugepd_page(*hpdp);
 302         int i;
 303
 304         unsigned long pdmask = ~((1UL << pdshift) - 1);
 305         unsigned int num_hugepd = 1;
 306         unsigned int shift = hugepd_shift(*hpdp);
 307
 308         /* Note: On fsl the hpdp may be the first of several */
 309         if (shift > pdshift)
 310                 num_hugepd = 1 << (shift - pdshift);
 311
 312         start &= pdmask;
 313         if (start < floor)
 314                 return;
 315         if (ceiling) {
 316                 ceiling &= pdmask;
 317                 if (! ceiling)
 318                         return;
 319         }
 320         if (end - 1 > ceiling - 1)
 321                 return;
 322
 323         for (i = 0; i < num_hugepd; i++, hpdp++)
 324                 *hpdp = __hugepd(0);
 325
 326         if (shift >= pdshift)
 327                 hugepd_free(tlb, hugepte);
 328         else
 329                 pgtable_free_tlb(tlb, hugepte,
 330                                  get_hugepd_cache_index(pdshift - shift));
 331 }
 332
 333 static void hugetlb_free_pte_range(struct mmu_gather *tlb, pmd_t *pmd,
 334                                    unsigned long addr, unsigned long end,
 335                                    unsigned long floor, unsigned long ceiling)
 336 {
 337         unsigned long start = addr;
 338         pgtable_t token = pmd_pgtable(*pmd);
 339
 340         start &= PMD_MASK;
 341         if (start < floor)
 342                 return;
 343         if (ceiling) {
 344                 ceiling &= PMD_MASK;
 345                 if (!ceiling)
 346                         return;
 347         }
 348         if (end - 1 > ceiling - 1)
 349                 return;
 350
 351         pmd_clear(pmd);
 352         pte_free_tlb(tlb, token, addr);
 353         mm_dec_nr_ptes(tlb->mm);
 354 }
 355
 356 static void hugetlb_free_pmd_range(struct mmu_gather *tlb, pud_t *pud,
 357                                    unsigned long addr, unsigned long end,
 358                                    unsigned long floor, unsigned long ceiling)
 359 {
 360         pmd_t *pmd;
 361         unsigned long next;
 362         unsigned long start;
 363
 364         start = addr;
 365         do {
 366                 unsigned long more;
 367
 368                 pmd = pmd_offset(pud, addr);
 369                 next = pmd_addr_end(addr, end);
 370                 if (!is_hugepd(__hugepd(pmd_val(*pmd)))) {
 371                         if (pmd_none_or_clear_bad(pmd))
 372                                 continue;
 373
 374                         /*
 375                          * if it is not hugepd pointer, we should already find
 376                          * it cleared.
 377                          */
 378                         WARN_ON(!IS_ENABLED(CONFIG_PPC_8xx));
 379
 380                         hugetlb_free_pte_range(tlb, pmd, addr, end, floor, ceiling);
 381
 382                         continue;
 383                 }
 384                 /*
 385                  * Increment next by the size of the huge mapping since
 386                  * there may be more than one entry at this level for a
 387                  * single hugepage, but all of them point to
 388                  * the same kmem cache that holds the hugepte.
 389                  */
 390                 more = addr + (1 << hugepd_shift(*(hugepd_t *)pmd));
 391                 if (more > next)
 392                         next = more;
 393
 394                 free_hugepd_range(tlb, (hugepd_t *)pmd, PMD_SHIFT,
 395                                   addr, next, floor, ceiling);
 396         } while (addr = next, addr != end);
 397
 398         start &= PUD_MASK;
 399         if (start < floor)
 400                 return;
 401         if (ceiling) {
 402                 ceiling &= PUD_MASK;
 403                 if (!ceiling)
 404                         return;
 405         }
 406         if (end - 1 > ceiling - 1)
 407                 return;
 408
 409         pmd = pmd_offset(pud, start);
 410         pud_clear(pud);
 411         pmd_free_tlb(tlb, pmd, start);
 412         mm_dec_nr_pmds(tlb->mm);
 413 }
 414
 415 static void hugetlb_free_pud_range(struct mmu_gather *tlb, p4d_t *p4d,
 416                                    unsigned long addr, unsigned long end,
 417                                    unsigned long floor, unsigned long ceiling)
 418 {
 419         pud_t *pud;
 420         unsigned long next;
 421         unsigned long start;
 422
 423         start = addr;
 424         do {
 425                 pud = pud_offset(p4d, addr);
 426                 next = pud_addr_end(addr, end);
 427                 if (!is_hugepd(__hugepd(pud_val(*pud)))) {
 428                         if (pud_none_or_clear_bad(pud))
 429                                 continue;
 430                         hugetlb_free_pmd_range(tlb, pud, addr, next, floor,
 431                                                ceiling);
 432                 } else {
 433                         unsigned long more;
 434                         /*
 435                          * Increment next by the size of the huge mapping since
 436                          * there may be more than one entry at this level for a
 437                          * single hugepage, but all of them point to
 438                          * the same kmem cache that holds the hugepte.
 439                          */
 440                         more = addr + (1 << hugepd_shift(*(hugepd_t *)pud));
 441                         if (more > next)
 442                                 next = more;
 443
 444                         free_hugepd_range(tlb, (hugepd_t *)pud, PUD_SHIFT,
 445                                           addr, next, floor, ceiling);
 446                 }
 447         } while (addr = next, addr != end);
 448
 449         start &= PGDIR_MASK;
 450         if (start < floor)
 451                 return;
 452         if (ceiling) {
 453                 ceiling &= PGDIR_MASK;
 454                 if (!ceiling)
 455                         return;
 456         }
 457         if (end - 1 > ceiling - 1)
 458                 return;
 459
 460         pud = pud_offset(p4d, start);
 461         p4d_clear(p4d);
 462         pud_free_tlb(tlb, pud, start);
 463         mm_dec_nr_puds(tlb->mm);
 464 }
 465
 466 /*
 467  * This function frees user-level page tables of a process.
 468  */
 469 void hugetlb_free_pgd_range(struct mmu_gather *tlb,
 470                             unsigned long addr, unsigned long end,
 471                             unsigned long floor, unsigned long ceiling)
 472 {
 473         pgd_t *pgd;
 474         p4d_t *p4d;
 475         unsigned long next;
 476
 477         /*
 478          * Because there are a number of different possible pagetable
 479          * layouts for hugepage ranges, we limit knowledge of how
 480          * things should be laid out to the allocation path
 481          * (huge_pte_alloc(), above).  Everything else works out the
 482          * structure as it goes from information in the hugepd
 483          * pointers.  That means that we can't here use the
 484          * optimization used in the normal page free_pgd_range(), of
 485          * checking whether we're actually covering a large enough
 486          * range to have to do anything at the top level of the walk
 487          * instead of at the bottom.
 488          *
 489          * To make sense of this, you should probably go read the big
 490          * block comment at the top of the normal free_pgd_range(),
 491          * too.
 492          */
 493
 494         do {
 495                 next = pgd_addr_end(addr, end);
 496                 pgd = pgd_offset(tlb->mm, addr);
 497                 p4d = p4d_offset(pgd, addr);
 498                 if (!is_hugepd(__hugepd(pgd_val(*pgd)))) {
 499                         if (p4d_none_or_clear_bad(p4d))
 500                                 continue;
 501                         hugetlb_free_pud_range(tlb, p4d, addr, next, floor, ceiling);
 502                 } else {
 503                         unsigned long more;
 504                         /*
 505                          * Increment next by the size of the huge mapping since
 506                          * there may be more than one entry at the pgd level
 507                          * for a single hugepage, but all of them point to the
 508                          * same kmem cache that holds the hugepte.
 509                          */
 510                         more = addr + (1 << hugepd_shift(*(hugepd_t *)pgd));
 511                         if (more > next)
 512                                 next = more;
 513
 514                         free_hugepd_range(tlb, (hugepd_t *)p4d, PGDIR_SHIFT,
 515                                           addr, next, floor, ceiling);
 516                 }
 517         } while (addr = next, addr != end);
 518 }
 519
 520 struct page *follow_huge_pd(struct vm_area_struct *vma,
 521                             unsigned long address, hugepd_t hpd,
 522                             int flags, int pdshift)
 523 {
 524         pte_t *ptep;
 525         spinlock_t *ptl;
 526         struct page *page = NULL;
 527         unsigned long mask;
 528         int shift = hugepd_shift(hpd);
 529         struct mm_struct *mm = vma->vm_mm;
 530
 531 retry:
 532         /*
 533          * hugepage directory entries are protected by mm->page_table_lock
 534          * Use this instead of huge_pte_lockptr
 535          */
 536         ptl = &mm->page_table_lock;
 537         spin_lock(ptl);
 538
 539         ptep = hugepte_offset(hpd, address, pdshift);
 540         if (pte_present(*ptep)) {
 541                 mask = (1UL << shift) - 1;
 542                 page = pte_page(*ptep);
 543                 page += ((address & mask) >> PAGE_SHIFT);
 544                 if (flags & FOLL_GET)
 545                         get_page(page);
 546         } else {
 547                 if (is_hugetlb_entry_migration(*ptep)) {
 548                         spin_unlock(ptl);
 549                         __migration_entry_wait(mm, ptep, ptl);
 550                         goto retry;
 551                 }
 552         }
 553         spin_unlock(ptl);
 554         return page;
 555 }
 556
 557 #ifdef CONFIG_PPC_MM_SLICES
 558 unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 559                                         unsigned long len, unsigned long pgoff,
 560                                         unsigned long flags)
 561 {
 562         struct hstate *hstate = hstate_file(file);
 563         int mmu_psize = shift_to_mmu_psize(huge_page_shift(hstate));
 564
 565 #ifdef CONFIG_PPC_RADIX_MMU
 566         if (radix_enabled())
 567                 return radix__hugetlb_get_unmapped_area(file, addr, len,
 568                                                        pgoff, flags);
 569 #endif
 570         return slice_get_unmapped_area(addr, len, flags, mmu_psize, 1);
 571 }
 572 #endif
 573
 574 unsigned long vma_mmu_pagesize(struct vm_area_struct *vma)
 575 {
 576         /* With radix we don't use slice, so derive it from vma*/
 577         if (IS_ENABLED(CONFIG_PPC_MM_SLICES) && !radix_enabled()) {
 578                 unsigned int psize = get_slice_psize(vma->vm_mm, vma->vm_start);
 579
 580                 return 1UL << mmu_psize_to_shift(psize);
 581         }
 582         return vma_kernel_pagesize(vma);
 583 }
 584
 585 bool __init arch_hugetlb_valid_size(unsigned long size)
 586 {
 587         int shift = __ffs(size);
 588         int mmu_psize;
 589
 590         /* Check that it is a page size supported by the hardware and
 591          * that it fits within pagetable and slice limits. */
 592         if (size <= PAGE_SIZE || !is_power_of_2(size))
 593                 return false;
 594
 595         mmu_psize = check_and_get_huge_psize(shift);
 596         if (mmu_psize < 0)
 597                 return false;
 598
 599         BUG_ON(mmu_psize_defs[mmu_psize].shift != shift);
 600
 601         return true;
 602 }
 603
 604 static int __init add_huge_page_size(unsigned long long size)
 605 {
 606         int shift = __ffs(size);
 607
 608         if (!arch_hugetlb_valid_size((unsigned long)size))
 609                 return -EINVAL;
 610
 611         hugetlb_add_hstate(shift - PAGE_SHIFT);
 612         return 0;
 613 }
 614
 615 static int __init hugetlbpage_init(void)
 616 {
 617         bool configured = false;
 618         int psize;
 619
 620         if (hugetlb_disabled) {
 621                 pr_info("HugeTLB support is disabled!\n");
 622                 return 0;
 623         }
 624
 625         if (IS_ENABLED(CONFIG_PPC_BOOK3S_64) && !radix_enabled() &&
 626             !mmu_has_feature(MMU_FTR_16M_PAGE))
 627                 return -ENODEV;
 628
 629         for (psize = 0; psize < MMU_PAGE_COUNT; ++psize) {
 630                 unsigned shift;
 631                 unsigned pdshift;
 632
 633                 if (!mmu_psize_defs[psize].shift)
 634                         continue;
 635
 636                 shift = mmu_psize_to_shift(psize);
 637
 638 #ifdef CONFIG_PPC_BOOK3S_64
 639                 if (shift > PGDIR_SHIFT)
 640                         continue;
 641                 else if (shift > PUD_SHIFT)
 642                         pdshift = PGDIR_SHIFT;
 643                 else if (shift > PMD_SHIFT)
 644                         pdshift = PUD_SHIFT;
 645                 else
 646                         pdshift = PMD_SHIFT;
 647 #else
 648                 if (shift < PUD_SHIFT)
 649                         pdshift = PMD_SHIFT;
 650                 else if (shift < PGDIR_SHIFT)
 651                         pdshift = PUD_SHIFT;
 652                 else
 653                         pdshift = PGDIR_SHIFT;
 654 #endif
 655
 656                 if (add_huge_page_size(1ULL << shift) < 0)
 657                         continue;
 658                 /*
 659                  * if we have pdshift and shift value same, we don't
 660                  * use pgt cache for hugepd.
 661                  */
 662                 if (pdshift > shift) {
 663                         if (!IS_ENABLED(CONFIG_PPC_8xx))
 664                                 pgtable_cache_add(pdshift - shift);
 665                 } else if (IS_ENABLED(CONFIG_PPC_FSL_BOOK3E) ||
 666                            IS_ENABLED(CONFIG_PPC_8xx)) {
 667                         pgtable_cache_add(PTE_T_ORDER);
 668                 }
 669
 670                 configured = true;
 671         }
 672
 673         if (configured) {
 674                 if (IS_ENABLED(CONFIG_HUGETLB_PAGE_SIZE_VARIABLE))
 675                         hugetlbpage_init_default();
 676         } else
 677                 pr_info("Failed to initialize. Disabling HugeTLB");
 678
 679         return 0;
 680 }
 681
 682 arch_initcall(hugetlbpage_init);
 683
 684 void flush_dcache_icache_hugepage(struct page *page)
 685 {
 686         int i;
 687         void *start;
 688
 689         BUG_ON(!PageCompound(page));
 690
 691         for (i = 0; i < compound_nr(page); i++) {
 692                 if (!PageHighMem(page)) {
 693                         __flush_dcache_icache(page_address(page+i));
 694                 } else {
 695                         start = kmap_atomic(page+i);
 696                         __flush_dcache_icache(start);
 697                         kunmap_atomic(start);
 698                 }
 699         }
 700 }
 701
 702 void __init gigantic_hugetlb_cma_reserve(void)
 703 {
 704         unsigned long order = 0;
 705
 706         if (radix_enabled())
 707                 order = PUD_SHIFT - PAGE_SHIFT;
 708         else if (!firmware_has_feature(FW_FEATURE_LPAR) && mmu_psize_defs[MMU_PAGE_16G].shift)
 709                 /*
 710                  * For pseries we do use ibm,expected#pages for reserving 16G pages.
 711                  */
 712                 order = mmu_psize_to_shift(MMU_PAGE_16G) - PAGE_SHIFT;
 713
 714         if (order) {
 715                 VM_WARN_ON(order < MAX_ORDER);
 716                 hugetlb_cma_reserve(order);
 717         }
 718 }