arch/powerpc/mm/slice.c

   1 /*
   2  * address space "slices" (meta-segments) support
   3  *
   4  * Copyright (C) 2007 Benjamin Herrenschmidt, IBM Corporation.
   5  *
   6  * Based on hugetlb implementation
   7  *
   8  * Copyright (C) 2003 David Gibson, IBM Corporation.
   9  *
  10  * This program is free software; you can redistribute it and/or modify
  11  * it under the terms of the GNU General Public License as published by
  12  * the Free Software Foundation; either version 2 of the License, or
  13  * (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  23  */
  24
  25 #undef DEBUG
  26
  27 #include <linux/kernel.h>
  28 #include <linux/mm.h>
  29 #include <linux/pagemap.h>
  30 #include <linux/err.h>
  31 #include <linux/spinlock.h>
  32 #include <linux/export.h>
  33 #include <asm/mman.h>
  34 #include <asm/mmu.h>
  35 #include <asm/spu.h>
  36
  37 /* some sanity checks */
  38 #if (PGTABLE_RANGE >> 43) > SLICE_MASK_SIZE
  39 #error PGTABLE_RANGE exceeds slice_mask high_slices size
  40 #endif
  41
  42 static DEFINE_SPINLOCK(slice_convert_lock);
  43
  44
  45 #ifdef DEBUG
  46 int _slice_debug = 1;
  47
  48 static void slice_print_mask(const char *label, struct slice_mask mask)
  49 {
  50         char    *p, buf[16 + 3 + 64 + 1];
  51         int     i;
  52
  53         if (!_slice_debug)
  54                 return;
  55         p = buf;
  56         for (i = 0; i < SLICE_NUM_LOW; i++)
  57                 *(p++) = (mask.low_slices & (1 << i)) ? '1' : '0';
  58         *(p++) = ' ';
  59         *(p++) = '-';
  60         *(p++) = ' ';
  61         for (i = 0; i < SLICE_NUM_HIGH; i++)
  62                 *(p++) = (mask.high_slices & (1ul << i)) ? '1' : '0';
  63         *(p++) = 0;
  64
  65         printk(KERN_DEBUG "%s:%s\n", label, buf);
  66 }
  67
  68 #define slice_dbg(fmt...) do { if (_slice_debug) pr_debug(fmt); } while(0)
  69
  70 #else
  71
  72 static void slice_print_mask(const char *label, struct slice_mask mask) {}
  73 #define slice_dbg(fmt...)
  74
  75 #endif
  76
  77 static struct slice_mask slice_range_to_mask(unsigned long start,
  78                                              unsigned long len)
  79 {
  80         unsigned long end = start + len - 1;
  81         struct slice_mask ret = { 0, 0 };
  82
  83         if (start < SLICE_LOW_TOP) {
  84                 unsigned long mend = min(end, SLICE_LOW_TOP);
  85                 unsigned long mstart = min(start, SLICE_LOW_TOP);
  86
  87                 ret.low_slices = (1u << (GET_LOW_SLICE_INDEX(mend) + 1))
  88                         - (1u << GET_LOW_SLICE_INDEX(mstart));
  89         }
  90
  91         if ((start + len) > SLICE_LOW_TOP)
  92                 ret.high_slices = (1ul << (GET_HIGH_SLICE_INDEX(end) + 1))
  93                         - (1ul << GET_HIGH_SLICE_INDEX(start));
  94
  95         return ret;
  96 }
  97
  98 static int slice_area_is_free(struct mm_struct *mm, unsigned long addr,
  99                               unsigned long len)
 100 {
 101         struct vm_area_struct *vma;
 102
 103         if ((mm->task_size - len) < addr)
 104                 return 0;
 105         vma = find_vma(mm, addr);
 106         return (!vma || (addr + len) <= vma->vm_start);
 107 }
 108
 109 static int slice_low_has_vma(struct mm_struct *mm, unsigned long slice)
 110 {
 111         return !slice_area_is_free(mm, slice << SLICE_LOW_SHIFT,
 112                                    1ul << SLICE_LOW_SHIFT);
 113 }
 114
 115 static int slice_high_has_vma(struct mm_struct *mm, unsigned long slice)
 116 {
 117         unsigned long start = slice << SLICE_HIGH_SHIFT;
 118         unsigned long end = start + (1ul << SLICE_HIGH_SHIFT);
 119
 120         /* Hack, so that each addresses is controlled by exactly one
 121          * of the high or low area bitmaps, the first high area starts
 122          * at 4GB, not 0 */
 123         if (start == 0)
 124                 start = SLICE_LOW_TOP;
 125
 126         return !slice_area_is_free(mm, start, end - start);
 127 }
 128
 129 static struct slice_mask slice_mask_for_free(struct mm_struct *mm)
 130 {
 131         struct slice_mask ret = { 0, 0 };
 132         unsigned long i;
 133
 134         for (i = 0; i < SLICE_NUM_LOW; i++)
 135                 if (!slice_low_has_vma(mm, i))
 136                         ret.low_slices |= 1u << i;
 137
 138         if (mm->task_size <= SLICE_LOW_TOP)
 139                 return ret;
 140
 141         for (i = 0; i < SLICE_NUM_HIGH; i++)
 142                 if (!slice_high_has_vma(mm, i))
 143                         ret.high_slices |= 1ul << i;
 144
 145         return ret;
 146 }
 147
 148 static struct slice_mask slice_mask_for_size(struct mm_struct *mm, int psize)
 149 {
 150         unsigned char *hpsizes;
 151         int index, mask_index;
 152         struct slice_mask ret = { 0, 0 };
 153         unsigned long i;
 154         u64 lpsizes;
 155
 156         lpsizes = mm->context.low_slices_psize;
 157         for (i = 0; i < SLICE_NUM_LOW; i++)
 158                 if (((lpsizes >> (i * 4)) & 0xf) == psize)
 159                         ret.low_slices |= 1u << i;
 160
 161         hpsizes = mm->context.high_slices_psize;
 162         for (i = 0; i < SLICE_NUM_HIGH; i++) {
 163                 mask_index = i & 0x1;
 164                 index = i >> 1;
 165                 if (((hpsizes[index] >> (mask_index * 4)) & 0xf) == psize)
 166                         ret.high_slices |= 1ul << i;
 167         }
 168
 169         return ret;
 170 }
 171
 172 static int slice_check_fit(struct slice_mask mask, struct slice_mask available)
 173 {
 174         return (mask.low_slices & available.low_slices) == mask.low_slices &&
 175                 (mask.high_slices & available.high_slices) == mask.high_slices;
 176 }
 177
 178 static void slice_flush_segments(void *parm)
 179 {
 180         struct mm_struct *mm = parm;
 181         unsigned long flags;
 182
 183         if (mm != current->active_mm)
 184                 return;
 185
 186         /* update the paca copy of the context struct */
 187         get_paca()->context = current->active_mm->context;
 188
 189         local_irq_save(flags);
 190         slb_flush_and_rebolt();
 191         local_irq_restore(flags);
 192 }
 193
 194 static void slice_convert(struct mm_struct *mm, struct slice_mask mask, int psize)
 195 {
 196         int index, mask_index;
 197         /* Write the new slice psize bits */
 198         unsigned char *hpsizes;
 199         u64 lpsizes;
 200         unsigned long i, flags;
 201
 202         slice_dbg("slice_convert(mm=%p, psize=%d)\n", mm, psize);
 203         slice_print_mask(" mask", mask);
 204
 205         /* We need to use a spinlock here to protect against
 206          * concurrent 64k -> 4k demotion ...
 207          */
 208         spin_lock_irqsave(&slice_convert_lock, flags);
 209
 210         lpsizes = mm->context.low_slices_psize;
 211         for (i = 0; i < SLICE_NUM_LOW; i++)
 212                 if (mask.low_slices & (1u << i))
 213                         lpsizes = (lpsizes & ~(0xful << (i * 4))) |
 214                                 (((unsigned long)psize) << (i * 4));
 215
 216         /* Assign the value back */
 217         mm->context.low_slices_psize = lpsizes;
 218
 219         hpsizes = mm->context.high_slices_psize;
 220         for (i = 0; i < SLICE_NUM_HIGH; i++) {
 221                 mask_index = i & 0x1;
 222                 index = i >> 1;
 223                 if (mask.high_slices & (1ul << i))
 224                         hpsizes[index] = (hpsizes[index] &
 225                                           ~(0xf << (mask_index * 4))) |
 226                                 (((unsigned long)psize) << (mask_index * 4));
 227         }
 228
 229         slice_dbg(" lsps=%lx, hsps=%lx\n",
 230                   mm->context.low_slices_psize,
 231                   mm->context.high_slices_psize);
 232
 233         spin_unlock_irqrestore(&slice_convert_lock, flags);
 234
 235 #ifdef CONFIG_SPU_BASE
 236         spu_flush_all_slbs(mm);
 237 #endif
 238 }
 239
 240 static unsigned long slice_find_area_bottomup(struct mm_struct *mm,
 241                                               unsigned long len,
 242                                               struct slice_mask available,
 243                                               int psize, int use_cache)
 244 {
 245         struct vm_area_struct *vma;
 246         unsigned long start_addr, addr;
 247         struct slice_mask mask;
 248         int pshift = max_t(int, mmu_psize_defs[psize].shift, PAGE_SHIFT);
 249
 250         if (use_cache) {
 251                 if (len <= mm->cached_hole_size) {
 252                         start_addr = addr = TASK_UNMAPPED_BASE;
 253                         mm->cached_hole_size = 0;
 254                 } else
 255                         start_addr = addr = mm->free_area_cache;
 256         } else
 257                 start_addr = addr = TASK_UNMAPPED_BASE;
 258
 259 full_search:
 260         for (;;) {
 261                 addr = _ALIGN_UP(addr, 1ul << pshift);
 262                 if ((TASK_SIZE - len) < addr)
 263                         break;
 264                 vma = find_vma(mm, addr);
 265                 BUG_ON(vma && (addr >= vma->vm_end));
 266
 267                 mask = slice_range_to_mask(addr, len);
 268                 if (!slice_check_fit(mask, available)) {
 269                         if (addr < SLICE_LOW_TOP)
 270                                 addr = _ALIGN_UP(addr + 1,  1ul << SLICE_LOW_SHIFT);
 271                         else
 272                                 addr = _ALIGN_UP(addr + 1,  1ul << SLICE_HIGH_SHIFT);
 273                         continue;
 274                 }
 275                 if (!vma || addr + len <= vma->vm_start) {
 276                         /*
 277                          * Remember the place where we stopped the search:
 278                          */
 279                         if (use_cache)
 280                                 mm->free_area_cache = addr + len;
 281                         return addr;
 282                 }
 283                 if (use_cache && (addr + mm->cached_hole_size) < vma->vm_start)
 284                         mm->cached_hole_size = vma->vm_start - addr;
 285                 addr = vma->vm_end;
 286         }
 287
 288         /* Make sure we didn't miss any holes */
 289         if (use_cache && start_addr != TASK_UNMAPPED_BASE) {
 290                 start_addr = addr = TASK_UNMAPPED_BASE;
 291                 mm->cached_hole_size = 0;
 292                 goto full_search;
 293         }
 294         return -ENOMEM;
 295 }
 296
 297 static unsigned long slice_find_area_topdown(struct mm_struct *mm,
 298                                              unsigned long len,
 299                                              struct slice_mask available,
 300                                              int psize, int use_cache)
 301 {
 302         struct vm_area_struct *vma;
 303         unsigned long addr;
 304         struct slice_mask mask;
 305         int pshift = max_t(int, mmu_psize_defs[psize].shift, PAGE_SHIFT);
 306
 307         /* check if free_area_cache is useful for us */
 308         if (use_cache) {
 309                 if (len <= mm->cached_hole_size) {
 310                         mm->cached_hole_size = 0;
 311                         mm->free_area_cache = mm->mmap_base;
 312                 }
 313
 314                 /* either no address requested or can't fit in requested
 315                  * address hole
 316                  */
 317                 addr = mm->free_area_cache;
 318
 319                 /* make sure it can fit in the remaining address space */
 320                 if (addr > len) {
 321                         addr = _ALIGN_DOWN(addr - len, 1ul << pshift);
 322                         mask = slice_range_to_mask(addr, len);
 323                         if (slice_check_fit(mask, available) &&
 324                             slice_area_is_free(mm, addr, len))
 325                                         /* remember the address as a hint for
 326                                          * next time
 327                                          */
 328                                         return (mm->free_area_cache = addr);
 329                 }
 330         }
 331
 332         addr = mm->mmap_base;
 333         while (addr > len) {
 334                 /* Go down by chunk size */
 335                 addr = _ALIGN_DOWN(addr - len, 1ul << pshift);
 336
 337                 /* Check for hit with different page size */
 338                 mask = slice_range_to_mask(addr, len);
 339                 if (!slice_check_fit(mask, available)) {
 340                         if (addr < SLICE_LOW_TOP)
 341                                 addr = _ALIGN_DOWN(addr, 1ul << SLICE_LOW_SHIFT);
 342                         else if (addr < (1ul << SLICE_HIGH_SHIFT))
 343                                 addr = SLICE_LOW_TOP;
 344                         else
 345                                 addr = _ALIGN_DOWN(addr, 1ul << SLICE_HIGH_SHIFT);
 346                         continue;
 347                 }
 348
 349                 /*
 350                  * Lookup failure means no vma is above this address,
 351                  * else if new region fits below vma->vm_start,
 352                  * return with success:
 353                  */
 354                 vma = find_vma(mm, addr);
 355                 if (!vma || (addr + len) <= vma->vm_start) {
 356                         /* remember the address as a hint for next time */
 357                         if (use_cache)
 358                                 mm->free_area_cache = addr;
 359                         return addr;
 360                 }
 361
 362                 /* remember the largest hole we saw so far */
 363                 if (use_cache && (addr + mm->cached_hole_size) < vma->vm_start)
 364                         mm->cached_hole_size = vma->vm_start - addr;
 365
 366                 /* try just below the current vma->vm_start */
 367                 addr = vma->vm_start;
 368         }
 369
 370         /*
 371          * A failed mmap() very likely causes application failure,
 372          * so fall back to the bottom-up function here. This scenario
 373          * can happen with large stack limits and large mmap()
 374          * allocations.
 375          */
 376         addr = slice_find_area_bottomup(mm, len, available, psize, 0);
 377
 378         /*
 379          * Restore the topdown base:
 380          */
 381         if (use_cache) {
 382                 mm->free_area_cache = mm->mmap_base;
 383                 mm->cached_hole_size = ~0UL;
 384         }
 385
 386         return addr;
 387 }
 388
 389
 390 static unsigned long slice_find_area(struct mm_struct *mm, unsigned long len,
 391                                      struct slice_mask mask, int psize,
 392                                      int topdown, int use_cache)
 393 {
 394         if (topdown)
 395                 return slice_find_area_topdown(mm, len, mask, psize, use_cache);
 396         else
 397                 return slice_find_area_bottomup(mm, len, mask, psize, use_cache);
 398 }
 399
 400 #define or_mask(dst, src)       do {                    \
 401         (dst).low_slices |= (src).low_slices;           \
 402         (dst).high_slices |= (src).high_slices;         \
 403 } while (0)
 404
 405 #define andnot_mask(dst, src)   do {                    \
 406         (dst).low_slices &= ~(src).low_slices;          \
 407         (dst).high_slices &= ~(src).high_slices;        \
 408 } while (0)
 409
 410 #ifdef CONFIG_PPC_64K_PAGES
 411 #define MMU_PAGE_BASE   MMU_PAGE_64K
 412 #else
 413 #define MMU_PAGE_BASE   MMU_PAGE_4K
 414 #endif
 415
 416 unsigned long slice_get_unmapped_area(unsigned long addr, unsigned long len,
 417                                       unsigned long flags, unsigned int psize,
 418                                       int topdown, int use_cache)
 419 {
 420         struct slice_mask mask = {0, 0};
 421         struct slice_mask good_mask;
 422         struct slice_mask potential_mask = {0,0} /* silence stupid warning */;
 423         struct slice_mask compat_mask = {0, 0};
 424         int fixed = (flags & MAP_FIXED);
 425         int pshift = max_t(int, mmu_psize_defs[psize].shift, PAGE_SHIFT);
 426         struct mm_struct *mm = current->mm;
 427         unsigned long newaddr;
 428
 429         /* Sanity checks */
 430         BUG_ON(mm->task_size == 0);
 431
 432         slice_dbg("slice_get_unmapped_area(mm=%p, psize=%d...\n", mm, psize);
 433         slice_dbg(" addr=%lx, len=%lx, flags=%lx, topdown=%d, use_cache=%d\n",
 434                   addr, len, flags, topdown, use_cache);
 435
 436         if (len > mm->task_size)
 437                 return -ENOMEM;
 438         if (len & ((1ul << pshift) - 1))
 439                 return -EINVAL;
 440         if (fixed && (addr & ((1ul << pshift) - 1)))
 441                 return -EINVAL;
 442         if (fixed && addr > (mm->task_size - len))
 443                 return -EINVAL;
 444
 445         /* If hint, make sure it matches our alignment restrictions */
 446         if (!fixed && addr) {
 447                 addr = _ALIGN_UP(addr, 1ul << pshift);
 448                 slice_dbg(" aligned addr=%lx\n", addr);
 449                 /* Ignore hint if it's too large or overlaps a VMA */
 450                 if (addr > mm->task_size - len ||
 451                     !slice_area_is_free(mm, addr, len))
 452                         addr = 0;
 453         }
 454
 455         /* First make up a "good" mask of slices that have the right size
 456          * already
 457          */
 458         good_mask = slice_mask_for_size(mm, psize);
 459         slice_print_mask(" good_mask", good_mask);
 460
 461         /*
 462          * Here "good" means slices that are already the right page size,
 463          * "compat" means slices that have a compatible page size (i.e.
 464          * 4k in a 64k pagesize kernel), and "free" means slices without
 465          * any VMAs.
 466          *
 467          * If MAP_FIXED:
 468          *      check if fits in good | compat => OK
 469          *      check if fits in good | compat | free => convert free
 470          *      else bad
 471          * If have hint:
 472          *      check if hint fits in good => OK
 473          *      check if hint fits in good | free => convert free
 474          * Otherwise:
 475          *      search in good, found => OK
 476          *      search in good | free, found => convert free
 477          *      search in good | compat | free, found => convert free.
 478          */
 479
 480 #ifdef CONFIG_PPC_64K_PAGES
 481         /* If we support combo pages, we can allow 64k pages in 4k slices */
 482         if (psize == MMU_PAGE_64K) {
 483                 compat_mask = slice_mask_for_size(mm, MMU_PAGE_4K);
 484                 if (fixed)
 485                         or_mask(good_mask, compat_mask);
 486         }
 487 #endif
 488
 489         /* First check hint if it's valid or if we have MAP_FIXED */
 490         if (addr != 0 || fixed) {
 491                 /* Build a mask for the requested range */
 492                 mask = slice_range_to_mask(addr, len);
 493                 slice_print_mask(" mask", mask);
 494
 495                 /* Check if we fit in the good mask. If we do, we just return,
 496                  * nothing else to do
 497                  */
 498                 if (slice_check_fit(mask, good_mask)) {
 499                         slice_dbg(" fits good !\n");
 500                         return addr;
 501                 }
 502         } else {
 503                 /* Now let's see if we can find something in the existing
 504                  * slices for that size
 505                  */
 506                 newaddr = slice_find_area(mm, len, good_mask, psize, topdown,
 507                                           use_cache);
 508                 if (newaddr != -ENOMEM) {
 509                         /* Found within the good mask, we don't have to setup,
 510                          * we thus return directly
 511                          */
 512                         slice_dbg(" found area at 0x%lx\n", newaddr);
 513                         return newaddr;
 514                 }
 515         }
 516
 517         /* We don't fit in the good mask, check what other slices are
 518          * empty and thus can be converted
 519          */
 520         potential_mask = slice_mask_for_free(mm);
 521         or_mask(potential_mask, good_mask);
 522         slice_print_mask(" potential", potential_mask);
 523
 524         if ((addr != 0 || fixed) && slice_check_fit(mask, potential_mask)) {
 525                 slice_dbg(" fits potential !\n");
 526                 goto convert;
 527         }
 528
 529         /* If we have MAP_FIXED and failed the above steps, then error out */
 530         if (fixed)
 531                 return -EBUSY;
 532
 533         slice_dbg(" search...\n");
 534
 535         /* If we had a hint that didn't work out, see if we can fit
 536          * anywhere in the good area.
 537          */
 538         if (addr) {
 539                 addr = slice_find_area(mm, len, good_mask, psize, topdown,
 540                                        use_cache);
 541                 if (addr != -ENOMEM) {
 542                         slice_dbg(" found area at 0x%lx\n", addr);
 543                         return addr;
 544                 }
 545         }
 546
 547         /* Now let's see if we can find something in the existing slices
 548          * for that size plus free slices
 549          */
 550         addr = slice_find_area(mm, len, potential_mask, psize, topdown,
 551                                use_cache);
 552
 553 #ifdef CONFIG_PPC_64K_PAGES
 554         if (addr == -ENOMEM && psize == MMU_PAGE_64K) {
 555                 /* retry the search with 4k-page slices included */
 556                 or_mask(potential_mask, compat_mask);
 557                 addr = slice_find_area(mm, len, potential_mask, psize,
 558                                        topdown, use_cache);
 559         }
 560 #endif
 561
 562         if (addr == -ENOMEM)
 563                 return -ENOMEM;
 564
 565         mask = slice_range_to_mask(addr, len);
 566         slice_dbg(" found potential area at 0x%lx\n", addr);
 567         slice_print_mask(" mask", mask);
 568
 569  convert:
 570         andnot_mask(mask, good_mask);
 571         andnot_mask(mask, compat_mask);
 572         if (mask.low_slices || mask.high_slices) {
 573                 slice_convert(mm, mask, psize);
 574                 if (psize > MMU_PAGE_BASE)
 575                         on_each_cpu(slice_flush_segments, mm, 1);
 576         }
 577         return addr;
 578
 579 }
 580 EXPORT_SYMBOL_GPL(slice_get_unmapped_area);
 581
 582 unsigned long arch_get_unmapped_area(struct file *filp,
 583                                      unsigned long addr,
 584                                      unsigned long len,
 585                                      unsigned long pgoff,
 586                                      unsigned long flags)
 587 {
 588         return slice_get_unmapped_area(addr, len, flags,
 589                                        current->mm->context.user_psize,
 590                                        0, 1);
 591 }
 592
 593 unsigned long arch_get_unmapped_area_topdown(struct file *filp,
 594                                              const unsigned long addr0,
 595                                              const unsigned long len,
 596                                              const unsigned long pgoff,
 597                                              const unsigned long flags)
 598 {
 599         return slice_get_unmapped_area(addr0, len, flags,
 600                                        current->mm->context.user_psize,
 601                                        1, 1);
 602 }
 603
 604 unsigned int get_slice_psize(struct mm_struct *mm, unsigned long addr)
 605 {
 606         unsigned char *hpsizes;
 607         int index, mask_index;
 608
 609         if (addr < SLICE_LOW_TOP) {
 610                 u64 lpsizes;
 611                 lpsizes = mm->context.low_slices_psize;
 612                 index = GET_LOW_SLICE_INDEX(addr);
 613                 return (lpsizes >> (index * 4)) & 0xf;
 614         }
 615         hpsizes = mm->context.high_slices_psize;
 616         index = GET_HIGH_SLICE_INDEX(addr);
 617         mask_index = index & 0x1;
 618         return (hpsizes[index >> 1] >> (mask_index * 4)) & 0xf;
 619 }
 620 EXPORT_SYMBOL_GPL(get_slice_psize);
 621
 622 /*
 623  * This is called by hash_page when it needs to do a lazy conversion of
 624  * an address space from real 64K pages to combo 4K pages (typically
 625  * when hitting a non cacheable mapping on a processor or hypervisor
 626  * that won't allow them for 64K pages).
 627  *
 628  * This is also called in init_new_context() to change back the user
 629  * psize from whatever the parent context had it set to
 630  * N.B. This may be called before mm->context.id has been set.
 631  *
 632  * This function will only change the content of the {low,high)_slice_psize
 633  * masks, it will not flush SLBs as this shall be handled lazily by the
 634  * caller.
 635  */
 636 void slice_set_user_psize(struct mm_struct *mm, unsigned int psize)
 637 {
 638         int index, mask_index;
 639         unsigned char *hpsizes;
 640         unsigned long flags, lpsizes;
 641         unsigned int old_psize;
 642         int i;
 643
 644         slice_dbg("slice_set_user_psize(mm=%p, psize=%d)\n", mm, psize);
 645
 646         spin_lock_irqsave(&slice_convert_lock, flags);
 647
 648         old_psize = mm->context.user_psize;
 649         slice_dbg(" old_psize=%d\n", old_psize);
 650         if (old_psize == psize)
 651                 goto bail;
 652
 653         mm->context.user_psize = psize;
 654         wmb();
 655
 656         lpsizes = mm->context.low_slices_psize;
 657         for (i = 0; i < SLICE_NUM_LOW; i++)
 658                 if (((lpsizes >> (i * 4)) & 0xf) == old_psize)
 659                         lpsizes = (lpsizes & ~(0xful << (i * 4))) |
 660                                 (((unsigned long)psize) << (i * 4));
 661         /* Assign the value back */
 662         mm->context.low_slices_psize = lpsizes;
 663
 664         hpsizes = mm->context.high_slices_psize;
 665         for (i = 0; i < SLICE_NUM_HIGH; i++) {
 666                 mask_index = i & 0x1;
 667                 index = i >> 1;
 668                 if (((hpsizes[index] >> (mask_index * 4)) & 0xf) == old_psize)
 669                         hpsizes[index] = (hpsizes[index] &
 670                                           ~(0xf << (mask_index * 4))) |
 671                                 (((unsigned long)psize) << (mask_index * 4));
 672         }
 673
 674
 675
 676
 677         slice_dbg(" lsps=%lx, hsps=%lx\n",
 678                   mm->context.low_slices_psize,
 679                   mm->context.high_slices_psize);
 680
 681  bail:
 682         spin_unlock_irqrestore(&slice_convert_lock, flags);
 683 }
 684
 685 void slice_set_psize(struct mm_struct *mm, unsigned long address,
 686                      unsigned int psize)
 687 {
 688         unsigned char *hpsizes;
 689         unsigned long i, flags;
 690         u64 *lpsizes;
 691
 692         spin_lock_irqsave(&slice_convert_lock, flags);
 693         if (address < SLICE_LOW_TOP) {
 694                 i = GET_LOW_SLICE_INDEX(address);
 695                 lpsizes = &mm->context.low_slices_psize;
 696                 *lpsizes = (*lpsizes & ~(0xful << (i * 4))) |
 697                         ((unsigned long) psize << (i * 4));
 698         } else {
 699                 int index, mask_index;
 700                 i = GET_HIGH_SLICE_INDEX(address);
 701                 hpsizes = mm->context.high_slices_psize;
 702                 mask_index = i & 0x1;
 703                 index = i >> 1;
 704                 hpsizes[index] = (hpsizes[index] &
 705                                   ~(0xf << (mask_index * 4))) |
 706                         (((unsigned long)psize) << (mask_index * 4));
 707         }
 708
 709         spin_unlock_irqrestore(&slice_convert_lock, flags);
 710
 711 #ifdef CONFIG_SPU_BASE
 712         spu_flush_all_slbs(mm);
 713 #endif
 714 }
 715
 716 void slice_set_range_psize(struct mm_struct *mm, unsigned long start,
 717                            unsigned long len, unsigned int psize)
 718 {
 719         struct slice_mask mask = slice_range_to_mask(start, len);
 720
 721         slice_convert(mm, mask, psize);
 722 }
 723
 724 /*
 725  * is_hugepage_only_range() is used by generic code to verify whether
 726  * a normal mmap mapping (non hugetlbfs) is valid on a given area.
 727  *
 728  * until the generic code provides a more generic hook and/or starts
 729  * calling arch get_unmapped_area for MAP_FIXED (which our implementation
 730  * here knows how to deal with), we hijack it to keep standard mappings
 731  * away from us.
 732  *
 733  * because of that generic code limitation, MAP_FIXED mapping cannot
 734  * "convert" back a slice with no VMAs to the standard page size, only
 735  * get_unmapped_area() can. It would be possible to fix it here but I
 736  * prefer working on fixing the generic code instead.
 737  *
 738  * WARNING: This will not work if hugetlbfs isn't enabled since the
 739  * generic code will redefine that function as 0 in that. This is ok
 740  * for now as we only use slices with hugetlbfs enabled. This should
 741  * be fixed as the generic code gets fixed.
 742  */
 743 int is_hugepage_only_range(struct mm_struct *mm, unsigned long addr,
 744                            unsigned long len)
 745 {
 746         struct slice_mask mask, available;
 747         unsigned int psize = mm->context.user_psize;
 748
 749         mask = slice_range_to_mask(addr, len);
 750         available = slice_mask_for_size(mm, psize);
 751 #ifdef CONFIG_PPC_64K_PAGES
 752         /* We need to account for 4k slices too */
 753         if (psize == MMU_PAGE_64K) {
 754                 struct slice_mask compat_mask;
 755                 compat_mask = slice_mask_for_size(mm, MMU_PAGE_4K);
 756                 or_mask(available, compat_mask);
 757         }
 758 #endif
 759
 760 #if 0 /* too verbose */
 761         slice_dbg("is_hugepage_only_range(mm=%p, addr=%lx, len=%lx)\n",
 762                  mm, addr, len);
 763         slice_print_mask(" mask", mask);
 764         slice_print_mask(" available", available);
 765 #endif
 766         return !slice_check_fit(mask, available);
 767 }
 768