git.oblomov.eu Git - linux-2.6/blob - arch/powerpc/mm/hugetlbpage.c

   1 /*
   2  * PPC64 (POWER4) Huge TLB Page Support for Kernel.
   3  *
   4  * Copyright (C) 2003 David Gibson, IBM Corporation.
   5  *
   6  * Based on the IA-32 version:
   7  * Copyright (C) 2002, Rohit Seth <rohit.seth@intel.com>
   8  */
   9
  10 #include <linux/init.h>
  11 #include <linux/fs.h>
  12 #include <linux/mm.h>
  13 #include <linux/hugetlb.h>
  14 #include <linux/pagemap.h>
  15 #include <linux/slab.h>
  16 #include <linux/err.h>
  17 #include <linux/sysctl.h>
  18 #include <asm/mman.h>
  19 #include <asm/pgalloc.h>
  20 #include <asm/tlb.h>
  21 #include <asm/tlbflush.h>
  22 #include <asm/mmu_context.h>
  23 #include <asm/machdep.h>
  24 #include <asm/cputable.h>
  25 #include <asm/spu.h>
  26
  27 #define PAGE_SHIFT_64K  16
  28 #define PAGE_SHIFT_16M  24
  29 #define PAGE_SHIFT_16G  34
  30
  31 #define NUM_LOW_AREAS   (0x100000000UL >> SID_SHIFT)
  32 #define NUM_HIGH_AREAS  (PGTABLE_RANGE >> HTLB_AREA_SHIFT)
  33 #define MAX_NUMBER_GPAGES       1024
  34
  35 /* Tracks the 16G pages after the device tree is scanned and before the
  36  * huge_boot_pages list is ready.  */
  37 static unsigned long gpage_freearray[MAX_NUMBER_GPAGES];
  38 static unsigned nr_gpages;
  39
  40 /* Array of valid huge page sizes - non-zero value(hugepte_shift) is
  41  * stored for the huge page sizes that are valid.
  42  */
  43 unsigned int mmu_huge_psizes[MMU_PAGE_COUNT] = { }; /* initialize all to 0 */
  44
  45 #define hugepte_shift                   mmu_huge_psizes
  46 #define PTRS_PER_HUGEPTE(psize)         (1 << hugepte_shift[psize])
  47 #define HUGEPTE_TABLE_SIZE(psize)       (sizeof(pte_t) << hugepte_shift[psize])
  48
  49 #define HUGEPD_SHIFT(psize)             (mmu_psize_to_shift(psize) \
  50                                                 + hugepte_shift[psize])
  51 #define HUGEPD_SIZE(psize)              (1UL << HUGEPD_SHIFT(psize))
  52 #define HUGEPD_MASK(psize)              (~(HUGEPD_SIZE(psize)-1))
  53
  54 /* Subtract one from array size because we don't need a cache for 4K since
  55  * is not a huge page size */
  56 #define huge_pgtable_cache(psize)       (pgtable_cache[HUGEPTE_CACHE_NUM \
  57                                                         + psize-1])
  58 #define HUGEPTE_CACHE_NAME(psize)       (huge_pgtable_cache_name[psize])
  59
  60 static const char *huge_pgtable_cache_name[MMU_PAGE_COUNT] = {
  61         "unused_4K", "hugepte_cache_64K", "unused_64K_AP",
  62         "hugepte_cache_1M", "hugepte_cache_16M", "hugepte_cache_16G"
  63 };
  64
  65 /* Flag to mark huge PD pointers.  This means pmd_bad() and pud_bad()
  66  * will choke on pointers to hugepte tables, which is handy for
  67  * catching screwups early. */
  68 #define HUGEPD_OK       0x1
  69
  70 typedef struct { unsigned long pd; } hugepd_t;
  71
  72 #define hugepd_none(hpd)        ((hpd).pd == 0)
  73
  74 static inline int shift_to_mmu_psize(unsigned int shift)
  75 {
  76         switch (shift) {
  77 #ifndef CONFIG_PPC_64K_PAGES
  78         case PAGE_SHIFT_64K:
  79             return MMU_PAGE_64K;
  80 #endif
  81         case PAGE_SHIFT_16M:
  82             return MMU_PAGE_16M;
  83         case PAGE_SHIFT_16G:
  84             return MMU_PAGE_16G;
  85         }
  86         return -1;
  87 }
  88
  89 static inline unsigned int mmu_psize_to_shift(unsigned int mmu_psize)
  90 {
  91         if (mmu_psize_defs[mmu_psize].shift)
  92                 return mmu_psize_defs[mmu_psize].shift;
  93         BUG();
  94 }
  95
  96 static inline pte_t *hugepd_page(hugepd_t hpd)
  97 {
  98         BUG_ON(!(hpd.pd & HUGEPD_OK));
  99         return (pte_t *)(hpd.pd & ~HUGEPD_OK);
 100 }
 101
 102 static inline pte_t *hugepte_offset(hugepd_t *hpdp, unsigned long addr,
 103                                     struct hstate *hstate)
 104 {
 105         unsigned int shift = huge_page_shift(hstate);
 106         int psize = shift_to_mmu_psize(shift);
 107         unsigned long idx = ((addr >> shift) & (PTRS_PER_HUGEPTE(psize)-1));
 108         pte_t *dir = hugepd_page(*hpdp);
 109
 110         return dir + idx;
 111 }
 112
 113 static int __hugepte_alloc(struct mm_struct *mm, hugepd_t *hpdp,
 114                            unsigned long address, unsigned int psize)
 115 {
 116         pte_t *new = kmem_cache_zalloc(huge_pgtable_cache(psize),
 117                                       GFP_KERNEL|__GFP_REPEAT);
 118
 119         if (! new)
 120                 return -ENOMEM;
 121
 122         spin_lock(&mm->page_table_lock);
 123         if (!hugepd_none(*hpdp))
 124                 kmem_cache_free(huge_pgtable_cache(psize), new);
 125         else
 126                 hpdp->pd = (unsigned long)new | HUGEPD_OK;
 127         spin_unlock(&mm->page_table_lock);
 128         return 0;
 129 }
 130
 131 /* Base page size affects how we walk hugetlb page tables */
 132 #ifdef CONFIG_PPC_64K_PAGES
 133 #define hpmd_offset(pud, addr, h)       pmd_offset(pud, addr)
 134 #define hpmd_alloc(mm, pud, addr, h)    pmd_alloc(mm, pud, addr)
 135 #else
 136 static inline
 137 pmd_t *hpmd_offset(pud_t *pud, unsigned long addr, struct hstate *hstate)
 138 {
 139         if (huge_page_shift(hstate) == PAGE_SHIFT_64K)
 140                 return pmd_offset(pud, addr);
 141         else
 142                 return (pmd_t *) pud;
 143 }
 144 static inline
 145 pmd_t *hpmd_alloc(struct mm_struct *mm, pud_t *pud, unsigned long addr,
 146                   struct hstate *hstate)
 147 {
 148         if (huge_page_shift(hstate) == PAGE_SHIFT_64K)
 149                 return pmd_alloc(mm, pud, addr);
 150         else
 151                 return (pmd_t *) pud;
 152 }
 153 #endif
 154
 155 /* Build list of addresses of gigantic pages.  This function is used in early
 156  * boot before the buddy or bootmem allocator is setup.
 157  */
 158 void add_gpage(unsigned long addr, unsigned long page_size,
 159         unsigned long number_of_pages)
 160 {
 161         if (!addr)
 162                 return;
 163         while (number_of_pages > 0) {
 164                 gpage_freearray[nr_gpages] = addr;
 165                 nr_gpages++;
 166                 number_of_pages--;
 167                 addr += page_size;
 168         }
 169 }
 170
 171 /* Moves the gigantic page addresses from the temporary list to the
 172  * huge_boot_pages list.
 173  */
 174 int alloc_bootmem_huge_page(struct hstate *hstate)
 175 {
 176         struct huge_bootmem_page *m;
 177         if (nr_gpages == 0)
 178                 return 0;
 179         m = phys_to_virt(gpage_freearray[--nr_gpages]);
 180         gpage_freearray[nr_gpages] = 0;
 181         list_add(&m->list, &huge_boot_pages);
 182         m->hstate = hstate;
 183         return 1;
 184 }
 185
 186
 187 /* Modelled after find_linux_pte() */
 188 pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
 189 {
 190         pgd_t *pg;
 191         pud_t *pu;
 192         pmd_t *pm;
 193
 194         unsigned int psize;
 195         unsigned int shift;
 196         unsigned long sz;
 197         struct hstate *hstate;
 198         psize = get_slice_psize(mm, addr);
 199         shift = mmu_psize_to_shift(psize);
 200         sz = ((1UL) << shift);
 201         hstate = size_to_hstate(sz);
 202
 203         addr &= hstate->mask;
 204
 205         pg = pgd_offset(mm, addr);
 206         if (!pgd_none(*pg)) {
 207                 pu = pud_offset(pg, addr);
 208                 if (!pud_none(*pu)) {
 209                         pm = hpmd_offset(pu, addr, hstate);
 210                         if (!pmd_none(*pm))
 211                                 return hugepte_offset((hugepd_t *)pm, addr,
 212                                                       hstate);
 213                 }
 214         }
 215
 216         return NULL;
 217 }
 218
 219 pte_t *huge_pte_alloc(struct mm_struct *mm,
 220                         unsigned long addr, unsigned long sz)
 221 {
 222         pgd_t *pg;
 223         pud_t *pu;
 224         pmd_t *pm;
 225         hugepd_t *hpdp = NULL;
 226         struct hstate *hstate;
 227         unsigned int psize;
 228         hstate = size_to_hstate(sz);
 229
 230         psize = get_slice_psize(mm, addr);
 231         BUG_ON(!mmu_huge_psizes[psize]);
 232
 233         addr &= hstate->mask;
 234
 235         pg = pgd_offset(mm, addr);
 236         pu = pud_alloc(mm, pg, addr);
 237
 238         if (pu) {
 239                 pm = hpmd_alloc(mm, pu, addr, hstate);
 240                 if (pm)
 241                         hpdp = (hugepd_t *)pm;
 242         }
 243
 244         if (! hpdp)
 245                 return NULL;
 246
 247         if (hugepd_none(*hpdp) && __hugepte_alloc(mm, hpdp, addr, psize))
 248                 return NULL;
 249
 250         return hugepte_offset(hpdp, addr, hstate);
 251 }
 252
 253 int huge_pmd_unshare(struct mm_struct *mm, unsigned long *addr, pte_t *ptep)
 254 {
 255         return 0;
 256 }
 257
 258 static void free_hugepte_range(struct mmu_gather *tlb, hugepd_t *hpdp,
 259                                unsigned int psize)
 260 {
 261         pte_t *hugepte = hugepd_page(*hpdp);
 262
 263         hpdp->pd = 0;
 264         tlb->need_flush = 1;
 265         pgtable_free_tlb(tlb, pgtable_free_cache(hugepte,
 266                                                  HUGEPTE_CACHE_NUM+psize-1,
 267                                                  PGF_CACHENUM_MASK));
 268 }
 269
 270 static void hugetlb_free_pmd_range(struct mmu_gather *tlb, pud_t *pud,
 271                                    unsigned long addr, unsigned long end,
 272                                    unsigned long floor, unsigned long ceiling,
 273                                    unsigned int psize)
 274 {
 275         pmd_t *pmd;
 276         unsigned long next;
 277         unsigned long start;
 278
 279         start = addr;
 280         pmd = pmd_offset(pud, addr);
 281         do {
 282                 next = pmd_addr_end(addr, end);
 283                 if (pmd_none(*pmd))
 284                         continue;
 285                 free_hugepte_range(tlb, (hugepd_t *)pmd, psize);
 286         } while (pmd++, addr = next, addr != end);
 287
 288         start &= PUD_MASK;
 289         if (start < floor)
 290                 return;
 291         if (ceiling) {
 292                 ceiling &= PUD_MASK;
 293                 if (!ceiling)
 294                         return;
 295         }
 296         if (end - 1 > ceiling - 1)
 297                 return;
 298
 299         pmd = pmd_offset(pud, start);
 300         pud_clear(pud);
 301         pmd_free_tlb(tlb, pmd);
 302 }
 303
 304 static void hugetlb_free_pud_range(struct mmu_gather *tlb, pgd_t *pgd,
 305                                    unsigned long addr, unsigned long end,
 306                                    unsigned long floor, unsigned long ceiling)
 307 {
 308         pud_t *pud;
 309         unsigned long next;
 310         unsigned long start;
 311         unsigned int shift;
 312         unsigned int psize = get_slice_psize(tlb->mm, addr);
 313         shift = mmu_psize_to_shift(psize);
 314
 315         start = addr;
 316         pud = pud_offset(pgd, addr);
 317         do {
 318                 next = pud_addr_end(addr, end);
 319 #ifdef CONFIG_PPC_64K_PAGES
 320                 if (pud_none_or_clear_bad(pud))
 321                         continue;
 322                 hugetlb_free_pmd_range(tlb, pud, addr, next, floor, ceiling,
 323                                        psize);
 324 #else
 325                 if (shift == PAGE_SHIFT_64K) {
 326                         if (pud_none_or_clear_bad(pud))
 327                                 continue;
 328                         hugetlb_free_pmd_range(tlb, pud, addr, next, floor,
 329                                                ceiling, psize);
 330                 } else {
 331                         if (pud_none(*pud))
 332                                 continue;
 333                         free_hugepte_range(tlb, (hugepd_t *)pud, psize);
 334                 }
 335 #endif
 336         } while (pud++, addr = next, addr != end);
 337
 338         start &= PGDIR_MASK;
 339         if (start < floor)
 340                 return;
 341         if (ceiling) {
 342                 ceiling &= PGDIR_MASK;
 343                 if (!ceiling)
 344                         return;
 345         }
 346         if (end - 1 > ceiling - 1)
 347                 return;
 348
 349         pud = pud_offset(pgd, start);
 350         pgd_clear(pgd);
 351         pud_free_tlb(tlb, pud);
 352 }
 353
 354 /*
 355  * This function frees user-level page tables of a process.
 356  *
 357  * Must be called with pagetable lock held.
 358  */
 359 void hugetlb_free_pgd_range(struct mmu_gather *tlb,
 360                             unsigned long addr, unsigned long end,
 361                             unsigned long floor, unsigned long ceiling)
 362 {
 363         pgd_t *pgd;
 364         unsigned long next;
 365         unsigned long start;
 366
 367         /*
 368          * Comments below take from the normal free_pgd_range().  They
 369          * apply here too.  The tests against HUGEPD_MASK below are
 370          * essential, because we *don't* test for this at the bottom
 371          * level.  Without them we'll attempt to free a hugepte table
 372          * when we unmap just part of it, even if there are other
 373          * active mappings using it.
 374          *
 375          * The next few lines have given us lots of grief...
 376          *
 377          * Why are we testing HUGEPD* at this top level?  Because
 378          * often there will be no work to do at all, and we'd prefer
 379          * not to go all the way down to the bottom just to discover
 380          * that.
 381          *
 382          * Why all these "- 1"s?  Because 0 represents both the bottom
 383          * of the address space and the top of it (using -1 for the
 384          * top wouldn't help much: the masks would do the wrong thing).
 385          * The rule is that addr 0 and floor 0 refer to the bottom of
 386          * the address space, but end 0 and ceiling 0 refer to the top
 387          * Comparisons need to use "end - 1" and "ceiling - 1" (though
 388          * that end 0 case should be mythical).
 389          *
 390          * Wherever addr is brought up or ceiling brought down, we
 391          * must be careful to reject "the opposite 0" before it
 392          * confuses the subsequent tests.  But what about where end is
 393          * brought down by HUGEPD_SIZE below? no, end can't go down to
 394          * 0 there.
 395          *
 396          * Whereas we round start (addr) and ceiling down, by different
 397          * masks at different levels, in order to test whether a table
 398          * now has no other vmas using it, so can be freed, we don't
 399          * bother to round floor or end up - the tests don't need that.
 400          */
 401         unsigned int psize = get_slice_psize(tlb->mm, addr);
 402
 403         addr &= HUGEPD_MASK(psize);
 404         if (addr < floor) {
 405                 addr += HUGEPD_SIZE(psize);
 406                 if (!addr)
 407                         return;
 408         }
 409         if (ceiling) {
 410                 ceiling &= HUGEPD_MASK(psize);
 411                 if (!ceiling)
 412                         return;
 413         }
 414         if (end - 1 > ceiling - 1)
 415                 end -= HUGEPD_SIZE(psize);
 416         if (addr > end - 1)
 417                 return;
 418
 419         start = addr;
 420         pgd = pgd_offset(tlb->mm, addr);
 421         do {
 422                 psize = get_slice_psize(tlb->mm, addr);
 423                 BUG_ON(!mmu_huge_psizes[psize]);
 424                 next = pgd_addr_end(addr, end);
 425                 if (pgd_none_or_clear_bad(pgd))
 426                         continue;
 427                 hugetlb_free_pud_range(tlb, pgd, addr, next, floor, ceiling);
 428         } while (pgd++, addr = next, addr != end);
 429 }
 430
 431 void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
 432                      pte_t *ptep, pte_t pte)
 433 {
 434         if (pte_present(*ptep)) {
 435                 /* We open-code pte_clear because we need to pass the right
 436                  * argument to hpte_need_flush (huge / !huge). Might not be
 437                  * necessary anymore if we make hpte_need_flush() get the
 438                  * page size from the slices
 439                  */
 440                 unsigned int psize = get_slice_psize(mm, addr);
 441                 unsigned int shift = mmu_psize_to_shift(psize);
 442                 unsigned long sz = ((1UL) << shift);
 443                 struct hstate *hstate = size_to_hstate(sz);
 444                 pte_update(mm, addr & hstate->mask, ptep, ~0UL, 1);
 445         }
 446         *ptep = __pte(pte_val(pte) & ~_PAGE_HPTEFLAGS);
 447 }
 448
 449 pte_t huge_ptep_get_and_clear(struct mm_struct *mm, unsigned long addr,
 450                               pte_t *ptep)
 451 {
 452         unsigned long old = pte_update(mm, addr, ptep, ~0UL, 1);
 453         return __pte(old);
 454 }
 455
 456 struct page *
 457 follow_huge_addr(struct mm_struct *mm, unsigned long address, int write)
 458 {
 459         pte_t *ptep;
 460         struct page *page;
 461         unsigned int mmu_psize = get_slice_psize(mm, address);
 462
 463         /* Verify it is a huge page else bail. */
 464         if (!mmu_huge_psizes[mmu_psize])
 465                 return ERR_PTR(-EINVAL);
 466
 467         ptep = huge_pte_offset(mm, address);
 468         page = pte_page(*ptep);
 469         if (page) {
 470                 unsigned int shift = mmu_psize_to_shift(mmu_psize);
 471                 unsigned long sz = ((1UL) << shift);
 472                 page += (address % sz) / PAGE_SIZE;
 473         }
 474
 475         return page;
 476 }
 477
 478 int pmd_huge(pmd_t pmd)
 479 {
 480         return 0;
 481 }
 482
 483 int pud_huge(pud_t pud)
 484 {
 485         return 0;
 486 }
 487
 488 struct page *
 489 follow_huge_pmd(struct mm_struct *mm, unsigned long address,
 490                 pmd_t *pmd, int write)
 491 {
 492         BUG();
 493         return NULL;
 494 }
 495
 496
 497 unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 498                                         unsigned long len, unsigned long pgoff,
 499                                         unsigned long flags)
 500 {
 501         struct hstate *hstate = hstate_file(file);
 502         int mmu_psize = shift_to_mmu_psize(huge_page_shift(hstate));
 503         return slice_get_unmapped_area(addr, len, flags, mmu_psize, 1, 0);
 504 }
 505
 506 /*
 507  * Called by asm hashtable.S for doing lazy icache flush
 508  */
 509 static unsigned int hash_huge_page_do_lazy_icache(unsigned long rflags,
 510                                         pte_t pte, int trap, unsigned long sz)
 511 {
 512         struct page *page;
 513         int i;
 514
 515         if (!pfn_valid(pte_pfn(pte)))
 516                 return rflags;
 517
 518         page = pte_page(pte);
 519
 520         /* page is dirty */
 521         if (!test_bit(PG_arch_1, &page->flags) && !PageReserved(page)) {
 522                 if (trap == 0x400) {
 523                         for (i = 0; i < (sz / PAGE_SIZE); i++)
 524                                 __flush_dcache_icache(page_address(page+i));
 525                         set_bit(PG_arch_1, &page->flags);
 526                 } else {
 527                         rflags |= HPTE_R_N;
 528                 }
 529         }
 530         return rflags;
 531 }
 532
 533 int hash_huge_page(struct mm_struct *mm, unsigned long access,
 534                    unsigned long ea, unsigned long vsid, int local,
 535                    unsigned long trap)
 536 {
 537         pte_t *ptep;
 538         unsigned long old_pte, new_pte;
 539         unsigned long va, rflags, pa, sz;
 540         long slot;
 541         int err = 1;
 542         int ssize = user_segment_size(ea);
 543         unsigned int mmu_psize;
 544         int shift;
 545         mmu_psize = get_slice_psize(mm, ea);
 546
 547         if (!mmu_huge_psizes[mmu_psize])
 548                 goto out;
 549         ptep = huge_pte_offset(mm, ea);
 550
 551         /* Search the Linux page table for a match with va */
 552         va = hpt_va(ea, vsid, ssize);
 553
 554         /*
 555          * If no pte found or not present, send the problem up to
 556          * do_page_fault
 557          */
 558         if (unlikely(!ptep || pte_none(*ptep)))
 559                 goto out;
 560
 561         /*
 562          * Check the user's access rights to the page.  If access should be
 563          * prevented then send the problem up to do_page_fault.
 564          */
 565         if (unlikely(access & ~pte_val(*ptep)))
 566                 goto out;
 567         /*
 568          * At this point, we have a pte (old_pte) which can be used to build
 569          * or update an HPTE. There are 2 cases:
 570          *
 571          * 1. There is a valid (present) pte with no associated HPTE (this is
 572          *      the most common case)
 573          * 2. There is a valid (present) pte with an associated HPTE. The
 574          *      current values of the pp bits in the HPTE prevent access
 575          *      because we are doing software DIRTY bit management and the
 576          *      page is currently not DIRTY.
 577          */
 578
 579
 580         do {
 581                 old_pte = pte_val(*ptep);
 582                 if (old_pte & _PAGE_BUSY)
 583                         goto out;
 584                 new_pte = old_pte | _PAGE_BUSY | _PAGE_ACCESSED;
 585         } while(old_pte != __cmpxchg_u64((unsigned long *)ptep,
 586                                          old_pte, new_pte));
 587
 588         rflags = 0x2 | (!(new_pte & _PAGE_RW));
 589         /* _PAGE_EXEC -> HW_NO_EXEC since it's inverted */
 590         rflags |= ((new_pte & _PAGE_EXEC) ? 0 : HPTE_R_N);
 591         shift = mmu_psize_to_shift(mmu_psize);
 592         sz = ((1UL) << shift);
 593         if (!cpu_has_feature(CPU_FTR_COHERENT_ICACHE))
 594                 /* No CPU has hugepages but lacks no execute, so we
 595                  * don't need to worry about that case */
 596                 rflags = hash_huge_page_do_lazy_icache(rflags, __pte(old_pte),
 597                                                        trap, sz);
 598
 599         /* Check if pte already has an hpte (case 2) */
 600         if (unlikely(old_pte & _PAGE_HASHPTE)) {
 601                 /* There MIGHT be an HPTE for this pte */
 602                 unsigned long hash, slot;
 603
 604                 hash = hpt_hash(va, shift, ssize);
 605                 if (old_pte & _PAGE_F_SECOND)
 606                         hash = ~hash;
 607                 slot = (hash & htab_hash_mask) * HPTES_PER_GROUP;
 608                 slot += (old_pte & _PAGE_F_GIX) >> 12;
 609
 610                 if (ppc_md.hpte_updatepp(slot, rflags, va, mmu_psize,
 611                                          ssize, local) == -1)
 612                         old_pte &= ~_PAGE_HPTEFLAGS;
 613         }
 614
 615         if (likely(!(old_pte & _PAGE_HASHPTE))) {
 616                 unsigned long hash = hpt_hash(va, shift, ssize);
 617                 unsigned long hpte_group;
 618
 619                 pa = pte_pfn(__pte(old_pte)) << PAGE_SHIFT;
 620
 621 repeat:
 622                 hpte_group = ((hash & htab_hash_mask) *
 623                               HPTES_PER_GROUP) & ~0x7UL;
 624
 625                 /* clear HPTE slot informations in new PTE */
 626 #ifdef CONFIG_PPC_64K_PAGES
 627                 new_pte = (new_pte & ~_PAGE_HPTEFLAGS) | _PAGE_HPTE_SUB0;
 628 #else
 629                 new_pte = (new_pte & ~_PAGE_HPTEFLAGS) | _PAGE_HASHPTE;
 630 #endif
 631                 /* Add in WIMG bits */
 632                 rflags |= (new_pte & (_PAGE_WRITETHRU | _PAGE_NO_CACHE |
 633                                       _PAGE_COHERENT | _PAGE_GUARDED));
 634
 635                 /* Insert into the hash table, primary slot */
 636                 slot = ppc_md.hpte_insert(hpte_group, va, pa, rflags, 0,
 637                                           mmu_psize, ssize);
 638
 639                 /* Primary is full, try the secondary */
 640                 if (unlikely(slot == -1)) {
 641                         hpte_group = ((~hash & htab_hash_mask) *
 642                                       HPTES_PER_GROUP) & ~0x7UL;
 643                         slot = ppc_md.hpte_insert(hpte_group, va, pa, rflags,
 644                                                   HPTE_V_SECONDARY,
 645                                                   mmu_psize, ssize);
 646                         if (slot == -1) {
 647                                 if (mftb() & 0x1)
 648                                         hpte_group = ((hash & htab_hash_mask) *
 649                                                       HPTES_PER_GROUP)&~0x7UL;
 650
 651                                 ppc_md.hpte_remove(hpte_group);
 652                                 goto repeat;
 653                         }
 654                 }
 655
 656                 if (unlikely(slot == -2))
 657                         panic("hash_huge_page: pte_insert failed\n");
 658
 659                 new_pte |= (slot << 12) & (_PAGE_F_SECOND | _PAGE_F_GIX);
 660         }
 661
 662         /*
 663          * No need to use ldarx/stdcx here
 664          */
 665         *ptep = __pte(new_pte & ~_PAGE_BUSY);
 666
 667         err = 0;
 668
 669  out:
 670         return err;
 671 }
 672
 673 void set_huge_psize(int psize)
 674 {
 675         /* Check that it is a page size supported by the hardware and
 676          * that it fits within pagetable limits. */
 677         if (mmu_psize_defs[psize].shift &&
 678                 mmu_psize_defs[psize].shift < SID_SHIFT_1T &&
 679                 (mmu_psize_defs[psize].shift > MIN_HUGEPTE_SHIFT ||
 680                  mmu_psize_defs[psize].shift == PAGE_SHIFT_64K ||
 681                  mmu_psize_defs[psize].shift == PAGE_SHIFT_16G)) {
 682                 /* Return if huge page size has already been setup or is the
 683                  * same as the base page size. */
 684                 if (mmu_huge_psizes[psize] ||
 685                    mmu_psize_defs[psize].shift == PAGE_SHIFT)
 686                         return;
 687                 hugetlb_add_hstate(mmu_psize_defs[psize].shift - PAGE_SHIFT);
 688
 689                 switch (mmu_psize_defs[psize].shift) {
 690                 case PAGE_SHIFT_64K:
 691                     /* We only allow 64k hpages with 4k base page,
 692                      * which was checked above, and always put them
 693                      * at the PMD */
 694                     hugepte_shift[psize] = PMD_SHIFT;
 695                     break;
 696                 case PAGE_SHIFT_16M:
 697                     /* 16M pages can be at two different levels
 698                      * of pagestables based on base page size */
 699                     if (PAGE_SHIFT == PAGE_SHIFT_64K)
 700                             hugepte_shift[psize] = PMD_SHIFT;
 701                     else /* 4k base page */
 702                             hugepte_shift[psize] = PUD_SHIFT;
 703                     break;
 704                 case PAGE_SHIFT_16G:
 705                     /* 16G pages are always at PGD level */
 706                     hugepte_shift[psize] = PGDIR_SHIFT;
 707                     break;
 708                 }
 709                 hugepte_shift[psize] -= mmu_psize_defs[psize].shift;
 710         } else
 711                 hugepte_shift[psize] = 0;
 712 }
 713
 714 static int __init hugepage_setup_sz(char *str)
 715 {
 716         unsigned long long size;
 717         int mmu_psize;
 718         int shift;
 719
 720         size = memparse(str, &str);
 721
 722         shift = __ffs(size);
 723         mmu_psize = shift_to_mmu_psize(shift);
 724         if (mmu_psize >= 0 && mmu_psize_defs[mmu_psize].shift)
 725                 set_huge_psize(mmu_psize);
 726         else
 727                 printk(KERN_WARNING "Invalid huge page size specified(%llu)\n", size);
 728
 729         return 1;
 730 }
 731 __setup("hugepagesz=", hugepage_setup_sz);
 732
 733 static int __init hugetlbpage_init(void)
 734 {
 735         unsigned int psize;
 736
 737         if (!cpu_has_feature(CPU_FTR_16M_PAGE))
 738                 return -ENODEV;
 739         /* Add supported huge page sizes.  Need to change HUGE_MAX_HSTATE
 740          * and adjust PTE_NONCACHE_NUM if the number of supported huge page
 741          * sizes changes.
 742          */
 743         set_huge_psize(MMU_PAGE_16M);
 744         set_huge_psize(MMU_PAGE_64K);
 745         set_huge_psize(MMU_PAGE_16G);
 746
 747         for (psize = 0; psize < MMU_PAGE_COUNT; ++psize) {
 748                 if (mmu_huge_psizes[psize]) {
 749                         huge_pgtable_cache(psize) = kmem_cache_create(
 750                                                 HUGEPTE_CACHE_NAME(psize),
 751                                                 HUGEPTE_TABLE_SIZE(psize),
 752                                                 HUGEPTE_TABLE_SIZE(psize),
 753                                                 0,
 754                                                 NULL);
 755                         if (!huge_pgtable_cache(psize))
 756                                 panic("hugetlbpage_init(): could not create %s"\
 757                                       "\n", HUGEPTE_CACHE_NAME(psize));
 758                 }
 759         }
 760
 761         return 0;
 762 }
 763
 764 module_init(hugetlbpage_init);