arch/ppc64/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/smp_lock.h>
  16 #include <linux/slab.h>
  17 #include <linux/err.h>
  18 #include <linux/sysctl.h>
  19 #include <asm/mman.h>
  20 #include <asm/pgalloc.h>
  21 #include <asm/tlb.h>
  22 #include <asm/tlbflush.h>
  23 #include <asm/mmu_context.h>
  24 #include <asm/machdep.h>
  25 #include <asm/cputable.h>
  26 #include <asm/tlb.h>
  27
  28 #include <linux/sysctl.h>
  29
  30 #define NUM_LOW_AREAS   (0x100000000UL >> SID_SHIFT)
  31 #define NUM_HIGH_AREAS  (PGTABLE_RANGE >> HTLB_AREA_SHIFT)
  32
  33 /* Modelled after find_linux_pte() */
  34 pte_t *huge_pte_offset(struct mm_struct *mm, unsigned long addr)
  35 {
  36         pgd_t *pg;
  37         pud_t *pu;
  38         pmd_t *pm;
  39         pte_t *pt;
  40
  41         BUG_ON(! in_hugepage_area(mm->context, addr));
  42
  43         addr &= HPAGE_MASK;
  44
  45         pg = pgd_offset(mm, addr);
  46         if (!pgd_none(*pg)) {
  47                 pu = pud_offset(pg, addr);
  48                 if (!pud_none(*pu)) {
  49                         pm = pmd_offset(pu, addr);
  50                         pt = (pte_t *)pm;
  51                         BUG_ON(!pmd_none(*pm)
  52                                && !(pte_present(*pt) && pte_huge(*pt)));
  53                         return pt;
  54                 }
  55         }
  56
  57         return NULL;
  58 }
  59
  60 pte_t *huge_pte_alloc(struct mm_struct *mm, unsigned long addr)
  61 {
  62         pgd_t *pg;
  63         pud_t *pu;
  64         pmd_t *pm;
  65         pte_t *pt;
  66
  67         BUG_ON(! in_hugepage_area(mm->context, addr));
  68
  69         addr &= HPAGE_MASK;
  70
  71         pg = pgd_offset(mm, addr);
  72         pu = pud_alloc(mm, pg, addr);
  73
  74         if (pu) {
  75                 pm = pmd_alloc(mm, pu, addr);
  76                 if (pm) {
  77                         pt = (pte_t *)pm;
  78                         BUG_ON(!pmd_none(*pm)
  79                                && !(pte_present(*pt) && pte_huge(*pt)));
  80                         return pt;
  81                 }
  82         }
  83
  84         return NULL;
  85 }
  86
  87 #define HUGEPTE_BATCH_SIZE      (HPAGE_SIZE / PMD_SIZE)
  88
  89 void set_huge_pte_at(struct mm_struct *mm, unsigned long addr,
  90                      pte_t *ptep, pte_t pte)
  91 {
  92         int i;
  93
  94         if (pte_present(*ptep)) {
  95                 pte_clear(mm, addr, ptep);
  96                 flush_tlb_pending();
  97         }
  98
  99         for (i = 0; i < HUGEPTE_BATCH_SIZE; i++) {
 100                 *ptep = __pte(pte_val(pte) & ~_PAGE_HPTEFLAGS);
 101                 ptep++;
 102         }
 103 }
 104
 105 pte_t huge_ptep_get_and_clear(struct mm_struct *mm, unsigned long addr,
 106                               pte_t *ptep)
 107 {
 108         unsigned long old = pte_update(ptep, ~0UL);
 109         int i;
 110
 111         if (old & _PAGE_HASHPTE)
 112                 hpte_update(mm, addr, old, 0);
 113
 114         for (i = 1; i < HUGEPTE_BATCH_SIZE; i++)
 115                 ptep[i] = __pte(0);
 116
 117         return __pte(old);
 118 }
 119
 120 /*
 121  * This function checks for proper alignment of input addr and len parameters.
 122  */
 123 int is_aligned_hugepage_range(unsigned long addr, unsigned long len)
 124 {
 125         if (len & ~HPAGE_MASK)
 126                 return -EINVAL;
 127         if (addr & ~HPAGE_MASK)
 128                 return -EINVAL;
 129         if (! (within_hugepage_low_range(addr, len)
 130                || within_hugepage_high_range(addr, len)) )
 131                 return -EINVAL;
 132         return 0;
 133 }
 134
 135 static void flush_low_segments(void *parm)
 136 {
 137         u16 areas = (unsigned long) parm;
 138         unsigned long i;
 139
 140         asm volatile("isync" : : : "memory");
 141
 142         BUILD_BUG_ON((sizeof(areas)*8) != NUM_LOW_AREAS);
 143
 144         for (i = 0; i < NUM_LOW_AREAS; i++) {
 145                 if (! (areas & (1U << i)))
 146                         continue;
 147                 asm volatile("slbie %0" : : "r" (i << SID_SHIFT));
 148         }
 149
 150         asm volatile("isync" : : : "memory");
 151 }
 152
 153 static void flush_high_segments(void *parm)
 154 {
 155         u16 areas = (unsigned long) parm;
 156         unsigned long i, j;
 157
 158         asm volatile("isync" : : : "memory");
 159
 160         BUILD_BUG_ON((sizeof(areas)*8) != NUM_HIGH_AREAS);
 161
 162         for (i = 0; i < NUM_HIGH_AREAS; i++) {
 163                 if (! (areas & (1U << i)))
 164                         continue;
 165                 for (j = 0; j < (1UL << (HTLB_AREA_SHIFT-SID_SHIFT)); j++)
 166                         asm volatile("slbie %0"
 167                                      :: "r" ((i << HTLB_AREA_SHIFT) + (j << SID_SHIFT)));
 168         }
 169
 170         asm volatile("isync" : : : "memory");
 171 }
 172
 173 static int prepare_low_area_for_htlb(struct mm_struct *mm, unsigned long area)
 174 {
 175         unsigned long start = area << SID_SHIFT;
 176         unsigned long end = (area+1) << SID_SHIFT;
 177         struct vm_area_struct *vma;
 178
 179         BUG_ON(area >= NUM_LOW_AREAS);
 180
 181         /* Check no VMAs are in the region */
 182         vma = find_vma(mm, start);
 183         if (vma && (vma->vm_start < end))
 184                 return -EBUSY;
 185
 186         return 0;
 187 }
 188
 189 static int prepare_high_area_for_htlb(struct mm_struct *mm, unsigned long area)
 190 {
 191         unsigned long start = area << HTLB_AREA_SHIFT;
 192         unsigned long end = (area+1) << HTLB_AREA_SHIFT;
 193         struct vm_area_struct *vma;
 194
 195         BUG_ON(area >= NUM_HIGH_AREAS);
 196
 197         /* Check no VMAs are in the region */
 198         vma = find_vma(mm, start);
 199         if (vma && (vma->vm_start < end))
 200                 return -EBUSY;
 201
 202         return 0;
 203 }
 204
 205 static int open_low_hpage_areas(struct mm_struct *mm, u16 newareas)
 206 {
 207         unsigned long i;
 208
 209         BUILD_BUG_ON((sizeof(newareas)*8) != NUM_LOW_AREAS);
 210         BUILD_BUG_ON((sizeof(mm->context.low_htlb_areas)*8) != NUM_LOW_AREAS);
 211
 212         newareas &= ~(mm->context.low_htlb_areas);
 213         if (! newareas)
 214                 return 0; /* The segments we want are already open */
 215
 216         for (i = 0; i < NUM_LOW_AREAS; i++)
 217                 if ((1 << i) & newareas)
 218                         if (prepare_low_area_for_htlb(mm, i) != 0)
 219                                 return -EBUSY;
 220
 221         mm->context.low_htlb_areas |= newareas;
 222
 223         /* update the paca copy of the context struct */
 224         get_paca()->context = mm->context;
 225
 226         /* the context change must make it to memory before the flush,
 227          * so that further SLB misses do the right thing. */
 228         mb();
 229         on_each_cpu(flush_low_segments, (void *)(unsigned long)newareas, 0, 1);
 230
 231         return 0;
 232 }
 233
 234 static int open_high_hpage_areas(struct mm_struct *mm, u16 newareas)
 235 {
 236         unsigned long i;
 237
 238         BUILD_BUG_ON((sizeof(newareas)*8) != NUM_HIGH_AREAS);
 239         BUILD_BUG_ON((sizeof(mm->context.high_htlb_areas)*8)
 240                      != NUM_HIGH_AREAS);
 241
 242         newareas &= ~(mm->context.high_htlb_areas);
 243         if (! newareas)
 244                 return 0; /* The areas we want are already open */
 245
 246         for (i = 0; i < NUM_HIGH_AREAS; i++)
 247                 if ((1 << i) & newareas)
 248                         if (prepare_high_area_for_htlb(mm, i) != 0)
 249                                 return -EBUSY;
 250
 251         mm->context.high_htlb_areas |= newareas;
 252
 253         /* update the paca copy of the context struct */
 254         get_paca()->context = mm->context;
 255
 256         /* the context change must make it to memory before the flush,
 257          * so that further SLB misses do the right thing. */
 258         mb();
 259         on_each_cpu(flush_high_segments, (void *)(unsigned long)newareas, 0, 1);
 260
 261         return 0;
 262 }
 263
 264 int prepare_hugepage_range(unsigned long addr, unsigned long len)
 265 {
 266         int err;
 267
 268         if ( (addr+len) < addr )
 269                 return -EINVAL;
 270
 271         if ((addr + len) < 0x100000000UL)
 272                 err = open_low_hpage_areas(current->mm,
 273                                           LOW_ESID_MASK(addr, len));
 274         else
 275                 err = open_high_hpage_areas(current->mm,
 276                                             HTLB_AREA_MASK(addr, len));
 277         if (err) {
 278                 printk(KERN_DEBUG "prepare_hugepage_range(%lx, %lx)"
 279                        " failed (lowmask: 0x%04hx, highmask: 0x%04hx)\n",
 280                        addr, len,
 281                        LOW_ESID_MASK(addr, len), HTLB_AREA_MASK(addr, len));
 282                 return err;
 283         }
 284
 285         return 0;
 286 }
 287
 288 struct page *
 289 follow_huge_addr(struct mm_struct *mm, unsigned long address, int write)
 290 {
 291         pte_t *ptep;
 292         struct page *page;
 293
 294         if (! in_hugepage_area(mm->context, address))
 295                 return ERR_PTR(-EINVAL);
 296
 297         ptep = huge_pte_offset(mm, address);
 298         page = pte_page(*ptep);
 299         if (page)
 300                 page += (address % HPAGE_SIZE) / PAGE_SIZE;
 301
 302         return page;
 303 }
 304
 305 int pmd_huge(pmd_t pmd)
 306 {
 307         return 0;
 308 }
 309
 310 struct page *
 311 follow_huge_pmd(struct mm_struct *mm, unsigned long address,
 312                 pmd_t *pmd, int write)
 313 {
 314         BUG();
 315         return NULL;
 316 }
 317
 318 /* Because we have an exclusive hugepage region which lies within the
 319  * normal user address space, we have to take special measures to make
 320  * non-huge mmap()s evade the hugepage reserved regions. */
 321 unsigned long arch_get_unmapped_area(struct file *filp, unsigned long addr,
 322                                      unsigned long len, unsigned long pgoff,
 323                                      unsigned long flags)
 324 {
 325         struct mm_struct *mm = current->mm;
 326         struct vm_area_struct *vma;
 327         unsigned long start_addr;
 328
 329         if (len > TASK_SIZE)
 330                 return -ENOMEM;
 331
 332         if (addr) {
 333                 addr = PAGE_ALIGN(addr);
 334                 vma = find_vma(mm, addr);
 335                 if (((TASK_SIZE - len) >= addr)
 336                     && (!vma || (addr+len) <= vma->vm_start)
 337                     && !is_hugepage_only_range(mm, addr,len))
 338                         return addr;
 339         }
 340         if (len > mm->cached_hole_size) {
 341                 start_addr = addr = mm->free_area_cache;
 342         } else {
 343                 start_addr = addr = TASK_UNMAPPED_BASE;
 344                 mm->cached_hole_size = 0;
 345         }
 346
 347 full_search:
 348         vma = find_vma(mm, addr);
 349         while (TASK_SIZE - len >= addr) {
 350                 BUG_ON(vma && (addr >= vma->vm_end));
 351
 352                 if (touches_hugepage_low_range(mm, addr, len)) {
 353                         addr = ALIGN(addr+1, 1<<SID_SHIFT);
 354                         vma = find_vma(mm, addr);
 355                         continue;
 356                 }
 357                 if (touches_hugepage_high_range(mm, addr, len)) {
 358                         addr = ALIGN(addr+1, 1UL<<HTLB_AREA_SHIFT);
 359                         vma = find_vma(mm, addr);
 360                         continue;
 361                 }
 362                 if (!vma || addr + len <= vma->vm_start) {
 363                         /*
 364                          * Remember the place where we stopped the search:
 365                          */
 366                         mm->free_area_cache = addr + len;
 367                         return addr;
 368                 }
 369                 if (addr + mm->cached_hole_size < vma->vm_start)
 370                         mm->cached_hole_size = vma->vm_start - addr;
 371                 addr = vma->vm_end;
 372                 vma = vma->vm_next;
 373         }
 374
 375         /* Make sure we didn't miss any holes */
 376         if (start_addr != TASK_UNMAPPED_BASE) {
 377                 start_addr = addr = TASK_UNMAPPED_BASE;
 378                 mm->cached_hole_size = 0;
 379                 goto full_search;
 380         }
 381         return -ENOMEM;
 382 }
 383
 384 /*
 385  * This mmap-allocator allocates new areas top-down from below the
 386  * stack's low limit (the base):
 387  *
 388  * Because we have an exclusive hugepage region which lies within the
 389  * normal user address space, we have to take special measures to make
 390  * non-huge mmap()s evade the hugepage reserved regions.
 391  */
 392 unsigned long
 393 arch_get_unmapped_area_topdown(struct file *filp, const unsigned long addr0,
 394                           const unsigned long len, const unsigned long pgoff,
 395                           const unsigned long flags)
 396 {
 397         struct vm_area_struct *vma, *prev_vma;
 398         struct mm_struct *mm = current->mm;
 399         unsigned long base = mm->mmap_base, addr = addr0;
 400         unsigned long largest_hole = mm->cached_hole_size;
 401         int first_time = 1;
 402
 403         /* requested length too big for entire address space */
 404         if (len > TASK_SIZE)
 405                 return -ENOMEM;
 406
 407         /* dont allow allocations above current base */
 408         if (mm->free_area_cache > base)
 409                 mm->free_area_cache = base;
 410
 411         /* requesting a specific address */
 412         if (addr) {
 413                 addr = PAGE_ALIGN(addr);
 414                 vma = find_vma(mm, addr);
 415                 if (TASK_SIZE - len >= addr &&
 416                                 (!vma || addr + len <= vma->vm_start)
 417                                 && !is_hugepage_only_range(mm, addr,len))
 418                         return addr;
 419         }
 420
 421         if (len <= largest_hole) {
 422                 largest_hole = 0;
 423                 mm->free_area_cache = base;
 424         }
 425 try_again:
 426         /* make sure it can fit in the remaining address space */
 427         if (mm->free_area_cache < len)
 428                 goto fail;
 429
 430         /* either no address requested or cant fit in requested address hole */
 431         addr = (mm->free_area_cache - len) & PAGE_MASK;
 432         do {
 433 hugepage_recheck:
 434                 if (touches_hugepage_low_range(mm, addr, len)) {
 435                         addr = (addr & ((~0) << SID_SHIFT)) - len;
 436                         goto hugepage_recheck;
 437                 } else if (touches_hugepage_high_range(mm, addr, len)) {
 438                         addr = (addr & ((~0UL) << HTLB_AREA_SHIFT)) - len;
 439                         goto hugepage_recheck;
 440                 }
 441
 442                 /*
 443                  * Lookup failure means no vma is above this address,
 444                  * i.e. return with success:
 445                  */
 446                 if (!(vma = find_vma_prev(mm, addr, &prev_vma)))
 447                         return addr;
 448
 449                 /*
 450                  * new region fits between prev_vma->vm_end and
 451                  * vma->vm_start, use it:
 452                  */
 453                 if (addr+len <= vma->vm_start &&
 454                           (!prev_vma || (addr >= prev_vma->vm_end))) {
 455                         /* remember the address as a hint for next time */
 456                         mm->cached_hole_size = largest_hole;
 457                         return (mm->free_area_cache = addr);
 458                 } else {
 459                         /* pull free_area_cache down to the first hole */
 460                         if (mm->free_area_cache == vma->vm_end) {
 461                                 mm->free_area_cache = vma->vm_start;
 462                                 mm->cached_hole_size = largest_hole;
 463                         }
 464                 }
 465
 466                 /* remember the largest hole we saw so far */
 467                 if (addr + largest_hole < vma->vm_start)
 468                         largest_hole = vma->vm_start - addr;
 469
 470                 /* try just below the current vma->vm_start */
 471                 addr = vma->vm_start-len;
 472         } while (len <= vma->vm_start);
 473
 474 fail:
 475         /*
 476          * if hint left us with no space for the requested
 477          * mapping then try again:
 478          */
 479         if (first_time) {
 480                 mm->free_area_cache = base;
 481                 largest_hole = 0;
 482                 first_time = 0;
 483                 goto try_again;
 484         }
 485         /*
 486          * A failed mmap() very likely causes application failure,
 487          * so fall back to the bottom-up function here. This scenario
 488          * can happen with large stack limits and large mmap()
 489          * allocations.
 490          */
 491         mm->free_area_cache = TASK_UNMAPPED_BASE;
 492         mm->cached_hole_size = ~0UL;
 493         addr = arch_get_unmapped_area(filp, addr0, len, pgoff, flags);
 494         /*
 495          * Restore the topdown base:
 496          */
 497         mm->free_area_cache = base;
 498         mm->cached_hole_size = ~0UL;
 499
 500         return addr;
 501 }
 502
 503 static unsigned long htlb_get_low_area(unsigned long len, u16 segmask)
 504 {
 505         unsigned long addr = 0;
 506         struct vm_area_struct *vma;
 507
 508         vma = find_vma(current->mm, addr);
 509         while (addr + len <= 0x100000000UL) {
 510                 BUG_ON(vma && (addr >= vma->vm_end)); /* invariant */
 511
 512                 if (! __within_hugepage_low_range(addr, len, segmask)) {
 513                         addr = ALIGN(addr+1, 1<<SID_SHIFT);
 514                         vma = find_vma(current->mm, addr);
 515                         continue;
 516                 }
 517
 518                 if (!vma || (addr + len) <= vma->vm_start)
 519                         return addr;
 520                 addr = ALIGN(vma->vm_end, HPAGE_SIZE);
 521                 /* Depending on segmask this might not be a confirmed
 522                  * hugepage region, so the ALIGN could have skipped
 523                  * some VMAs */
 524                 vma = find_vma(current->mm, addr);
 525         }
 526
 527         return -ENOMEM;
 528 }
 529
 530 static unsigned long htlb_get_high_area(unsigned long len, u16 areamask)
 531 {
 532         unsigned long addr = 0x100000000UL;
 533         struct vm_area_struct *vma;
 534
 535         vma = find_vma(current->mm, addr);
 536         while (addr + len <= TASK_SIZE_USER64) {
 537                 BUG_ON(vma && (addr >= vma->vm_end)); /* invariant */
 538
 539                 if (! __within_hugepage_high_range(addr, len, areamask)) {
 540                         addr = ALIGN(addr+1, 1UL<<HTLB_AREA_SHIFT);
 541                         vma = find_vma(current->mm, addr);
 542                         continue;
 543                 }
 544
 545                 if (!vma || (addr + len) <= vma->vm_start)
 546                         return addr;
 547                 addr = ALIGN(vma->vm_end, HPAGE_SIZE);
 548                 /* Depending on segmask this might not be a confirmed
 549                  * hugepage region, so the ALIGN could have skipped
 550                  * some VMAs */
 551                 vma = find_vma(current->mm, addr);
 552         }
 553
 554         return -ENOMEM;
 555 }
 556
 557 unsigned long hugetlb_get_unmapped_area(struct file *file, unsigned long addr,
 558                                         unsigned long len, unsigned long pgoff,
 559                                         unsigned long flags)
 560 {
 561         int lastshift;
 562         u16 areamask, curareas;
 563
 564         if (len & ~HPAGE_MASK)
 565                 return -EINVAL;
 566
 567         if (!cpu_has_feature(CPU_FTR_16M_PAGE))
 568                 return -EINVAL;
 569
 570         if (test_thread_flag(TIF_32BIT)) {
 571                 curareas = current->mm->context.low_htlb_areas;
 572
 573                 /* First see if we can do the mapping in the existing
 574                  * low areas */
 575                 addr = htlb_get_low_area(len, curareas);
 576                 if (addr != -ENOMEM)
 577                         return addr;
 578
 579                 lastshift = 0;
 580                 for (areamask = LOW_ESID_MASK(0x100000000UL-len, len);
 581                      ! lastshift; areamask >>=1) {
 582                         if (areamask & 1)
 583                                 lastshift = 1;
 584
 585                         addr = htlb_get_low_area(len, curareas | areamask);
 586                         if ((addr != -ENOMEM)
 587                             && open_low_hpage_areas(current->mm, areamask) == 0)
 588                                 return addr;
 589                 }
 590         } else {
 591                 curareas = current->mm->context.high_htlb_areas;
 592
 593                 /* First see if we can do the mapping in the existing
 594                  * high areas */
 595                 addr = htlb_get_high_area(len, curareas);
 596                 if (addr != -ENOMEM)
 597                         return addr;
 598
 599                 lastshift = 0;
 600                 for (areamask = HTLB_AREA_MASK(TASK_SIZE_USER64-len, len);
 601                      ! lastshift; areamask >>=1) {
 602                         if (areamask & 1)
 603                                 lastshift = 1;
 604
 605                         addr = htlb_get_high_area(len, curareas | areamask);
 606                         if ((addr != -ENOMEM)
 607                             && open_high_hpage_areas(current->mm, areamask) == 0)
 608                                 return addr;
 609                 }
 610         }
 611         printk(KERN_DEBUG "hugetlb_get_unmapped_area() unable to open"
 612                " enough areas\n");
 613         return -ENOMEM;
 614 }
 615
 616 int hash_huge_page(struct mm_struct *mm, unsigned long access,
 617                    unsigned long ea, unsigned long vsid, int local)
 618 {
 619         pte_t *ptep;
 620         unsigned long va, vpn;
 621         pte_t old_pte, new_pte;
 622         unsigned long rflags, prpn;
 623         long slot;
 624         int err = 1;
 625
 626         spin_lock(&mm->page_table_lock);
 627
 628         ptep = huge_pte_offset(mm, ea);
 629
 630         /* Search the Linux page table for a match with va */
 631         va = (vsid << 28) | (ea & 0x0fffffff);
 632         vpn = va >> HPAGE_SHIFT;
 633
 634         /*
 635          * If no pte found or not present, send the problem up to
 636          * do_page_fault
 637          */
 638         if (unlikely(!ptep || pte_none(*ptep)))
 639                 goto out;
 640
 641 /*      BUG_ON(pte_bad(*ptep)); */
 642
 643         /*
 644          * Check the user's access rights to the page.  If access should be
 645          * prevented then send the problem up to do_page_fault.
 646          */
 647         if (unlikely(access & ~pte_val(*ptep)))
 648                 goto out;
 649         /*
 650          * At this point, we have a pte (old_pte) which can be used to build
 651          * or update an HPTE. There are 2 cases:
 652          *
 653          * 1. There is a valid (present) pte with no associated HPTE (this is
 654          *      the most common case)
 655          * 2. There is a valid (present) pte with an associated HPTE. The
 656          *      current values of the pp bits in the HPTE prevent access
 657          *      because we are doing software DIRTY bit management and the
 658          *      page is currently not DIRTY.
 659          */
 660
 661
 662         old_pte = *ptep;
 663         new_pte = old_pte;
 664
 665         rflags = 0x2 | (! (pte_val(new_pte) & _PAGE_RW));
 666         /* _PAGE_EXEC -> HW_NO_EXEC since it's inverted */
 667         rflags |= ((pte_val(new_pte) & _PAGE_EXEC) ? 0 : HW_NO_EXEC);
 668
 669         /* Check if pte already has an hpte (case 2) */
 670         if (unlikely(pte_val(old_pte) & _PAGE_HASHPTE)) {
 671                 /* There MIGHT be an HPTE for this pte */
 672                 unsigned long hash, slot;
 673
 674                 hash = hpt_hash(vpn, 1);
 675                 if (pte_val(old_pte) & _PAGE_SECONDARY)
 676                         hash = ~hash;
 677                 slot = (hash & htab_hash_mask) * HPTES_PER_GROUP;
 678                 slot += (pte_val(old_pte) & _PAGE_GROUP_IX) >> 12;
 679
 680                 if (ppc_md.hpte_updatepp(slot, rflags, va, 1, local) == -1)
 681                         pte_val(old_pte) &= ~_PAGE_HPTEFLAGS;
 682         }
 683
 684         if (likely(!(pte_val(old_pte) & _PAGE_HASHPTE))) {
 685                 unsigned long hash = hpt_hash(vpn, 1);
 686                 unsigned long hpte_group;
 687
 688                 prpn = pte_pfn(old_pte);
 689
 690 repeat:
 691                 hpte_group = ((hash & htab_hash_mask) *
 692                               HPTES_PER_GROUP) & ~0x7UL;
 693
 694                 /* Update the linux pte with the HPTE slot */
 695                 pte_val(new_pte) &= ~_PAGE_HPTEFLAGS;
 696                 pte_val(new_pte) |= _PAGE_HASHPTE;
 697
 698                 /* Add in WIMG bits */
 699                 /* XXX We should store these in the pte */
 700                 rflags |= _PAGE_COHERENT;
 701
 702                 slot = ppc_md.hpte_insert(hpte_group, va, prpn,
 703                                           HPTE_V_LARGE, rflags);
 704
 705                 /* Primary is full, try the secondary */
 706                 if (unlikely(slot == -1)) {
 707                         pte_val(new_pte) |= _PAGE_SECONDARY;
 708                         hpte_group = ((~hash & htab_hash_mask) *
 709                                       HPTES_PER_GROUP) & ~0x7UL;
 710                         slot = ppc_md.hpte_insert(hpte_group, va, prpn,
 711                                                   HPTE_V_LARGE, rflags);
 712                         if (slot == -1) {
 713                                 if (mftb() & 0x1)
 714                                         hpte_group = ((hash & htab_hash_mask) * HPTES_PER_GROUP) & ~0x7UL;
 715
 716                                 ppc_md.hpte_remove(hpte_group);
 717                                 goto repeat;
 718                         }
 719                 }
 720
 721                 if (unlikely(slot == -2))
 722                         panic("hash_huge_page: pte_insert failed\n");
 723
 724                 pte_val(new_pte) |= (slot<<12) & _PAGE_GROUP_IX;
 725
 726                 /*
 727                  * No need to use ldarx/stdcx here because all who
 728                  * might be updating the pte will hold the
 729                  * page_table_lock
 730                  */
 731                 *ptep = new_pte;
 732         }
 733
 734         err = 0;
 735
 736  out:
 737         spin_unlock(&mm->page_table_lock);
 738
 739         return err;
 740 }