arch/sparc/mm/tsb.c

   1 /* arch/sparc64/mm/tsb.c
   2  *
   3  * Copyright (C) 2006, 2008 David S. Miller <davem@davemloft.net>
   4  */
   5
   6 #include <linux/kernel.h>
   7 #include <linux/preempt.h>
   8 #include <linux/slab.h>
   9 #include <asm/page.h>
  10 #include <asm/pgtable.h>
  11 #include <asm/mmu_context.h>
  12 #include <asm/setup.h>
  13 #include <asm/tsb.h>
  14 #include <asm/tlb.h>
  15 #include <asm/oplib.h>
  16
  17 extern struct tsb swapper_tsb[KERNEL_TSB_NENTRIES];
  18
  19 static inline unsigned long tsb_hash(unsigned long vaddr, unsigned long hash_shift, unsigned long nentries)
  20 {
  21         vaddr >>= hash_shift;
  22         return vaddr & (nentries - 1);
  23 }
  24
  25 static inline int tag_compare(unsigned long tag, unsigned long vaddr)
  26 {
  27         return (tag == (vaddr >> 22));
  28 }
  29
  30 static void flush_tsb_kernel_range_scan(unsigned long start, unsigned long end)
  31 {
  32         unsigned long idx;
  33
  34         for (idx = 0; idx < KERNEL_TSB_NENTRIES; idx++) {
  35                 struct tsb *ent = &swapper_tsb[idx];
  36                 unsigned long match = idx << 13;
  37
  38                 match |= (ent->tag << 22);
  39                 if (match >= start && match < end)
  40                         ent->tag = (1UL << TSB_TAG_INVALID_BIT);
  41         }
  42 }
  43
  44 /* TSB flushes need only occur on the processor initiating the address
  45  * space modification, not on each cpu the address space has run on.
  46  * Only the TLB flush needs that treatment.
  47  */
  48
  49 void flush_tsb_kernel_range(unsigned long start, unsigned long end)
  50 {
  51         unsigned long v;
  52
  53         if ((end - start) >> PAGE_SHIFT >= 2 * KERNEL_TSB_NENTRIES)
  54                 return flush_tsb_kernel_range_scan(start, end);
  55
  56         for (v = start; v < end; v += PAGE_SIZE) {
  57                 unsigned long hash = tsb_hash(v, PAGE_SHIFT,
  58                                               KERNEL_TSB_NENTRIES);
  59                 struct tsb *ent = &swapper_tsb[hash];
  60
  61                 if (tag_compare(ent->tag, v))
  62                         ent->tag = (1UL << TSB_TAG_INVALID_BIT);
  63         }
  64 }
  65
  66 static void __flush_tsb_one_entry(unsigned long tsb, unsigned long v,
  67                                   unsigned long hash_shift,
  68                                   unsigned long nentries)
  69 {
  70         unsigned long tag, ent, hash;
  71
  72         v &= ~0x1UL;
  73         hash = tsb_hash(v, hash_shift, nentries);
  74         ent = tsb + (hash * sizeof(struct tsb));
  75         tag = (v >> 22UL);
  76
  77         tsb_flush(ent, tag);
  78 }
  79
  80 static void __flush_tsb_one(struct tlb_batch *tb, unsigned long hash_shift,
  81                             unsigned long tsb, unsigned long nentries)
  82 {
  83         unsigned long i;
  84
  85         for (i = 0; i < tb->tlb_nr; i++)
  86                 __flush_tsb_one_entry(tsb, tb->vaddrs[i], hash_shift, nentries);
  87 }
  88
  89 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
  90 static void __flush_huge_tsb_one_entry(unsigned long tsb, unsigned long v,
  91                                        unsigned long hash_shift,
  92                                        unsigned long nentries,
  93                                        unsigned int hugepage_shift)
  94 {
  95         unsigned int hpage_entries;
  96         unsigned int i;
  97
  98         hpage_entries = 1 << (hugepage_shift - hash_shift);
  99         for (i = 0; i < hpage_entries; i++)
 100                 __flush_tsb_one_entry(tsb, v + (i << hash_shift), hash_shift,
 101                                       nentries);
 102 }
 103
 104 static void __flush_huge_tsb_one(struct tlb_batch *tb, unsigned long hash_shift,
 105                                  unsigned long tsb, unsigned long nentries,
 106                                  unsigned int hugepage_shift)
 107 {
 108         unsigned long i;
 109
 110         for (i = 0; i < tb->tlb_nr; i++)
 111                 __flush_huge_tsb_one_entry(tsb, tb->vaddrs[i], hash_shift,
 112                                            nentries, hugepage_shift);
 113 }
 114 #endif
 115
 116 void flush_tsb_user(struct tlb_batch *tb)
 117 {
 118         struct mm_struct *mm = tb->mm;
 119         unsigned long nentries, base, flags;
 120
 121         spin_lock_irqsave(&mm->context.lock, flags);
 122
 123         if (tb->hugepage_shift < HPAGE_SHIFT) {
 124                 base = (unsigned long) mm->context.tsb_block[MM_TSB_BASE].tsb;
 125                 nentries = mm->context.tsb_block[MM_TSB_BASE].tsb_nentries;
 126                 if (tlb_type == cheetah_plus || tlb_type == hypervisor)
 127                         base = __pa(base);
 128                 if (tb->hugepage_shift == PAGE_SHIFT)
 129                         __flush_tsb_one(tb, PAGE_SHIFT, base, nentries);
 130 #if defined(CONFIG_HUGETLB_PAGE)
 131                 else
 132                         __flush_huge_tsb_one(tb, PAGE_SHIFT, base, nentries,
 133                                              tb->hugepage_shift);
 134 #endif
 135         }
 136 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
 137         else if (mm->context.tsb_block[MM_TSB_HUGE].tsb) {
 138                 base = (unsigned long) mm->context.tsb_block[MM_TSB_HUGE].tsb;
 139                 nentries = mm->context.tsb_block[MM_TSB_HUGE].tsb_nentries;
 140                 if (tlb_type == cheetah_plus || tlb_type == hypervisor)
 141                         base = __pa(base);
 142                 __flush_huge_tsb_one(tb, REAL_HPAGE_SHIFT, base, nentries,
 143                                      tb->hugepage_shift);
 144         }
 145 #endif
 146         spin_unlock_irqrestore(&mm->context.lock, flags);
 147 }
 148
 149 void flush_tsb_user_page(struct mm_struct *mm, unsigned long vaddr,
 150                          unsigned int hugepage_shift)
 151 {
 152         unsigned long nentries, base, flags;
 153
 154         spin_lock_irqsave(&mm->context.lock, flags);
 155
 156         if (hugepage_shift < HPAGE_SHIFT) {
 157                 base = (unsigned long) mm->context.tsb_block[MM_TSB_BASE].tsb;
 158                 nentries = mm->context.tsb_block[MM_TSB_BASE].tsb_nentries;
 159                 if (tlb_type == cheetah_plus || tlb_type == hypervisor)
 160                         base = __pa(base);
 161                 if (hugepage_shift == PAGE_SHIFT)
 162                         __flush_tsb_one_entry(base, vaddr, PAGE_SHIFT,
 163                                               nentries);
 164 #if defined(CONFIG_HUGETLB_PAGE)
 165                 else
 166                         __flush_huge_tsb_one_entry(base, vaddr, PAGE_SHIFT,
 167                                                    nentries, hugepage_shift);
 168 #endif
 169         }
 170 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
 171         else if (mm->context.tsb_block[MM_TSB_HUGE].tsb) {
 172                 base = (unsigned long) mm->context.tsb_block[MM_TSB_HUGE].tsb;
 173                 nentries = mm->context.tsb_block[MM_TSB_HUGE].tsb_nentries;
 174                 if (tlb_type == cheetah_plus || tlb_type == hypervisor)
 175                         base = __pa(base);
 176                 __flush_huge_tsb_one_entry(base, vaddr, REAL_HPAGE_SHIFT,
 177                                            nentries, hugepage_shift);
 178         }
 179 #endif
 180         spin_unlock_irqrestore(&mm->context.lock, flags);
 181 }
 182
 183 #define HV_PGSZ_IDX_BASE        HV_PGSZ_IDX_8K
 184 #define HV_PGSZ_MASK_BASE       HV_PGSZ_MASK_8K
 185
 186 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
 187 #define HV_PGSZ_IDX_HUGE        HV_PGSZ_IDX_4MB
 188 #define HV_PGSZ_MASK_HUGE       HV_PGSZ_MASK_4MB
 189 #endif
 190
 191 static void setup_tsb_params(struct mm_struct *mm, unsigned long tsb_idx, unsigned long tsb_bytes)
 192 {
 193         unsigned long tsb_reg, base, tsb_paddr;
 194         unsigned long page_sz, tte;
 195
 196         mm->context.tsb_block[tsb_idx].tsb_nentries =
 197                 tsb_bytes / sizeof(struct tsb);
 198
 199         switch (tsb_idx) {
 200         case MM_TSB_BASE:
 201                 base = TSBMAP_8K_BASE;
 202                 break;
 203 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
 204         case MM_TSB_HUGE:
 205                 base = TSBMAP_4M_BASE;
 206                 break;
 207 #endif
 208         default:
 209                 BUG();
 210         }
 211
 212         tte = pgprot_val(PAGE_KERNEL_LOCKED);
 213         tsb_paddr = __pa(mm->context.tsb_block[tsb_idx].tsb);
 214         BUG_ON(tsb_paddr & (tsb_bytes - 1UL));
 215
 216         /* Use the smallest page size that can map the whole TSB
 217          * in one TLB entry.
 218          */
 219         switch (tsb_bytes) {
 220         case 8192 << 0:
 221                 tsb_reg = 0x0UL;
 222 #ifdef DCACHE_ALIASING_POSSIBLE
 223                 base += (tsb_paddr & 8192);
 224 #endif
 225                 page_sz = 8192;
 226                 break;
 227
 228         case 8192 << 1:
 229                 tsb_reg = 0x1UL;
 230                 page_sz = 64 * 1024;
 231                 break;
 232
 233         case 8192 << 2:
 234                 tsb_reg = 0x2UL;
 235                 page_sz = 64 * 1024;
 236                 break;
 237
 238         case 8192 << 3:
 239                 tsb_reg = 0x3UL;
 240                 page_sz = 64 * 1024;
 241                 break;
 242
 243         case 8192 << 4:
 244                 tsb_reg = 0x4UL;
 245                 page_sz = 512 * 1024;
 246                 break;
 247
 248         case 8192 << 5:
 249                 tsb_reg = 0x5UL;
 250                 page_sz = 512 * 1024;
 251                 break;
 252
 253         case 8192 << 6:
 254                 tsb_reg = 0x6UL;
 255                 page_sz = 512 * 1024;
 256                 break;
 257
 258         case 8192 << 7:
 259                 tsb_reg = 0x7UL;
 260                 page_sz = 4 * 1024 * 1024;
 261                 break;
 262
 263         default:
 264                 printk(KERN_ERR "TSB[%s:%d]: Impossible TSB size %lu, killing process.\n",
 265                        current->comm, current->pid, tsb_bytes);
 266                 do_exit(SIGSEGV);
 267         }
 268         tte |= pte_sz_bits(page_sz);
 269
 270         if (tlb_type == cheetah_plus || tlb_type == hypervisor) {
 271                 /* Physical mapping, no locked TLB entry for TSB.  */
 272                 tsb_reg |= tsb_paddr;
 273
 274                 mm->context.tsb_block[tsb_idx].tsb_reg_val = tsb_reg;
 275                 mm->context.tsb_block[tsb_idx].tsb_map_vaddr = 0;
 276                 mm->context.tsb_block[tsb_idx].tsb_map_pte = 0;
 277         } else {
 278                 tsb_reg |= base;
 279                 tsb_reg |= (tsb_paddr & (page_sz - 1UL));
 280                 tte |= (tsb_paddr & ~(page_sz - 1UL));
 281
 282                 mm->context.tsb_block[tsb_idx].tsb_reg_val = tsb_reg;
 283                 mm->context.tsb_block[tsb_idx].tsb_map_vaddr = base;
 284                 mm->context.tsb_block[tsb_idx].tsb_map_pte = tte;
 285         }
 286
 287         /* Setup the Hypervisor TSB descriptor.  */
 288         if (tlb_type == hypervisor) {
 289                 struct hv_tsb_descr *hp = &mm->context.tsb_descr[tsb_idx];
 290
 291                 switch (tsb_idx) {
 292                 case MM_TSB_BASE:
 293                         hp->pgsz_idx = HV_PGSZ_IDX_BASE;
 294                         break;
 295 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
 296                 case MM_TSB_HUGE:
 297                         hp->pgsz_idx = HV_PGSZ_IDX_HUGE;
 298                         break;
 299 #endif
 300                 default:
 301                         BUG();
 302                 }
 303                 hp->assoc = 1;
 304                 hp->num_ttes = tsb_bytes / 16;
 305                 hp->ctx_idx = 0;
 306                 switch (tsb_idx) {
 307                 case MM_TSB_BASE:
 308                         hp->pgsz_mask = HV_PGSZ_MASK_BASE;
 309                         break;
 310 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
 311                 case MM_TSB_HUGE:
 312                         hp->pgsz_mask = HV_PGSZ_MASK_HUGE;
 313                         break;
 314 #endif
 315                 default:
 316                         BUG();
 317                 }
 318                 hp->tsb_base = tsb_paddr;
 319                 hp->resv = 0;
 320         }
 321 }
 322
 323 struct kmem_cache *pgtable_cache __read_mostly;
 324
 325 static struct kmem_cache *tsb_caches[8] __read_mostly;
 326
 327 static const char *tsb_cache_names[8] = {
 328         "tsb_8KB",
 329         "tsb_16KB",
 330         "tsb_32KB",
 331         "tsb_64KB",
 332         "tsb_128KB",
 333         "tsb_256KB",
 334         "tsb_512KB",
 335         "tsb_1MB",
 336 };
 337
 338 void __init pgtable_cache_init(void)
 339 {
 340         unsigned long i;
 341
 342         pgtable_cache = kmem_cache_create("pgtable_cache",
 343                                           PAGE_SIZE, PAGE_SIZE,
 344                                           0,
 345                                           _clear_page);
 346         if (!pgtable_cache) {
 347                 prom_printf("pgtable_cache_init(): Could not create!\n");
 348                 prom_halt();
 349         }
 350
 351         for (i = 0; i < ARRAY_SIZE(tsb_cache_names); i++) {
 352                 unsigned long size = 8192 << i;
 353                 const char *name = tsb_cache_names[i];
 354
 355                 tsb_caches[i] = kmem_cache_create(name,
 356                                                   size, size,
 357                                                   0, NULL);
 358                 if (!tsb_caches[i]) {
 359                         prom_printf("Could not create %s cache\n", name);
 360                         prom_halt();
 361                 }
 362         }
 363 }
 364
 365 int sysctl_tsb_ratio = -2;
 366
 367 static unsigned long tsb_size_to_rss_limit(unsigned long new_size)
 368 {
 369         unsigned long num_ents = (new_size / sizeof(struct tsb));
 370
 371         if (sysctl_tsb_ratio < 0)
 372                 return num_ents - (num_ents >> -sysctl_tsb_ratio);
 373         else
 374                 return num_ents + (num_ents >> sysctl_tsb_ratio);
 375 }
 376
 377 /* When the RSS of an address space exceeds tsb_rss_limit for a TSB,
 378  * do_sparc64_fault() invokes this routine to try and grow it.
 379  *
 380  * When we reach the maximum TSB size supported, we stick ~0UL into
 381  * tsb_rss_limit for that TSB so the grow checks in do_sparc64_fault()
 382  * will not trigger any longer.
 383  *
 384  * The TSB can be anywhere from 8K to 1MB in size, in increasing powers
 385  * of two.  The TSB must be aligned to it's size, so f.e. a 512K TSB
 386  * must be 512K aligned.  It also must be physically contiguous, so we
 387  * cannot use vmalloc().
 388  *
 389  * The idea here is to grow the TSB when the RSS of the process approaches
 390  * the number of entries that the current TSB can hold at once.  Currently,
 391  * we trigger when the RSS hits 3/4 of the TSB capacity.
 392  */
 393 void tsb_grow(struct mm_struct *mm, unsigned long tsb_index, unsigned long rss)
 394 {
 395         unsigned long max_tsb_size = 1 * 1024 * 1024;
 396         unsigned long new_size, old_size, flags;
 397         struct tsb *old_tsb, *new_tsb;
 398         unsigned long new_cache_index, old_cache_index;
 399         unsigned long new_rss_limit;
 400         gfp_t gfp_flags;
 401
 402         if (max_tsb_size > (PAGE_SIZE << MAX_ORDER))
 403                 max_tsb_size = (PAGE_SIZE << MAX_ORDER);
 404
 405         new_cache_index = 0;
 406         for (new_size = 8192; new_size < max_tsb_size; new_size <<= 1UL) {
 407                 new_rss_limit = tsb_size_to_rss_limit(new_size);
 408                 if (new_rss_limit > rss)
 409                         break;
 410                 new_cache_index++;
 411         }
 412
 413         if (new_size == max_tsb_size)
 414                 new_rss_limit = ~0UL;
 415
 416 retry_tsb_alloc:
 417         gfp_flags = GFP_KERNEL;
 418         if (new_size > (PAGE_SIZE * 2))
 419                 gfp_flags |= __GFP_NOWARN | __GFP_NORETRY;
 420
 421         new_tsb = kmem_cache_alloc_node(tsb_caches[new_cache_index],
 422                                         gfp_flags, numa_node_id());
 423         if (unlikely(!new_tsb)) {
 424                 /* Not being able to fork due to a high-order TSB
 425                  * allocation failure is very bad behavior.  Just back
 426                  * down to a 0-order allocation and force no TSB
 427                  * growing for this address space.
 428                  */
 429                 if (mm->context.tsb_block[tsb_index].tsb == NULL &&
 430                     new_cache_index > 0) {
 431                         new_cache_index = 0;
 432                         new_size = 8192;
 433                         new_rss_limit = ~0UL;
 434                         goto retry_tsb_alloc;
 435                 }
 436
 437                 /* If we failed on a TSB grow, we are under serious
 438                  * memory pressure so don't try to grow any more.
 439                  */
 440                 if (mm->context.tsb_block[tsb_index].tsb != NULL)
 441                         mm->context.tsb_block[tsb_index].tsb_rss_limit = ~0UL;
 442                 return;
 443         }
 444
 445         /* Mark all tags as invalid.  */
 446         tsb_init(new_tsb, new_size);
 447
 448         /* Ok, we are about to commit the changes.  If we are
 449          * growing an existing TSB the locking is very tricky,
 450          * so WATCH OUT!
 451          *
 452          * We have to hold mm->context.lock while committing to the
 453          * new TSB, this synchronizes us with processors in
 454          * flush_tsb_user() and switch_mm() for this address space.
 455          *
 456          * But even with that lock held, processors run asynchronously
 457          * accessing the old TSB via TLB miss handling.  This is OK
 458          * because those actions are just propagating state from the
 459          * Linux page tables into the TSB, page table mappings are not
 460          * being changed.  If a real fault occurs, the processor will
 461          * synchronize with us when it hits flush_tsb_user(), this is
 462          * also true for the case where vmscan is modifying the page
 463          * tables.  The only thing we need to be careful with is to
 464          * skip any locked TSB entries during copy_tsb().
 465          *
 466          * When we finish committing to the new TSB, we have to drop
 467          * the lock and ask all other cpus running this address space
 468          * to run tsb_context_switch() to see the new TSB table.
 469          */
 470         spin_lock_irqsave(&mm->context.lock, flags);
 471
 472         old_tsb = mm->context.tsb_block[tsb_index].tsb;
 473         old_cache_index =
 474                 (mm->context.tsb_block[tsb_index].tsb_reg_val & 0x7UL);
 475         old_size = (mm->context.tsb_block[tsb_index].tsb_nentries *
 476                     sizeof(struct tsb));
 477
 478
 479         /* Handle multiple threads trying to grow the TSB at the same time.
 480          * One will get in here first, and bump the size and the RSS limit.
 481          * The others will get in here next and hit this check.
 482          */
 483         if (unlikely(old_tsb &&
 484                      (rss < mm->context.tsb_block[tsb_index].tsb_rss_limit))) {
 485                 spin_unlock_irqrestore(&mm->context.lock, flags);
 486
 487                 kmem_cache_free(tsb_caches[new_cache_index], new_tsb);
 488                 return;
 489         }
 490
 491         mm->context.tsb_block[tsb_index].tsb_rss_limit = new_rss_limit;
 492
 493         if (old_tsb) {
 494                 extern void copy_tsb(unsigned long old_tsb_base,
 495                                      unsigned long old_tsb_size,
 496                                      unsigned long new_tsb_base,
 497                                      unsigned long new_tsb_size);
 498                 unsigned long old_tsb_base = (unsigned long) old_tsb;
 499                 unsigned long new_tsb_base = (unsigned long) new_tsb;
 500
 501                 if (tlb_type == cheetah_plus || tlb_type == hypervisor) {
 502                         old_tsb_base = __pa(old_tsb_base);
 503                         new_tsb_base = __pa(new_tsb_base);
 504                 }
 505                 copy_tsb(old_tsb_base, old_size, new_tsb_base, new_size);
 506         }
 507
 508         mm->context.tsb_block[tsb_index].tsb = new_tsb;
 509         setup_tsb_params(mm, tsb_index, new_size);
 510
 511         spin_unlock_irqrestore(&mm->context.lock, flags);
 512
 513         /* If old_tsb is NULL, we're being invoked for the first time
 514          * from init_new_context().
 515          */
 516         if (old_tsb) {
 517                 /* Reload it on the local cpu.  */
 518                 tsb_context_switch(mm);
 519
 520                 /* Now force other processors to do the same.  */
 521                 preempt_disable();
 522                 smp_tsb_sync(mm);
 523                 preempt_enable();
 524
 525                 /* Now it is safe to free the old tsb.  */
 526                 kmem_cache_free(tsb_caches[old_cache_index], old_tsb);
 527         }
 528 }
 529
 530 int init_new_context(struct task_struct *tsk, struct mm_struct *mm)
 531 {
 532         unsigned long mm_rss = get_mm_rss(mm);
 533 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
 534         unsigned long saved_hugetlb_pte_count;
 535         unsigned long saved_thp_pte_count;
 536 #endif
 537         unsigned int i;
 538
 539         spin_lock_init(&mm->context.lock);
 540
 541         mm->context.sparc64_ctx_val = 0UL;
 542
 543 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
 544         /* We reset them to zero because the fork() page copying
 545          * will re-increment the counters as the parent PTEs are
 546          * copied into the child address space.
 547          */
 548         saved_hugetlb_pte_count = mm->context.hugetlb_pte_count;
 549         saved_thp_pte_count = mm->context.thp_pte_count;
 550         mm->context.hugetlb_pte_count = 0;
 551         mm->context.thp_pte_count = 0;
 552
 553         mm_rss -= saved_thp_pte_count * (HPAGE_SIZE / PAGE_SIZE);
 554 #endif
 555
 556         /* copy_mm() copies over the parent's mm_struct before calling
 557          * us, so we need to zero out the TSB pointer or else tsb_grow()
 558          * will be confused and think there is an older TSB to free up.
 559          */
 560         for (i = 0; i < MM_NUM_TSBS; i++)
 561                 mm->context.tsb_block[i].tsb = NULL;
 562
 563         /* If this is fork, inherit the parent's TSB size.  We would
 564          * grow it to that size on the first page fault anyways.
 565          */
 566         tsb_grow(mm, MM_TSB_BASE, mm_rss);
 567
 568 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
 569         if (unlikely(saved_hugetlb_pte_count + saved_thp_pte_count))
 570                 tsb_grow(mm, MM_TSB_HUGE,
 571                          (saved_hugetlb_pte_count + saved_thp_pte_count) *
 572                          REAL_HPAGE_PER_HPAGE);
 573 #endif
 574
 575         if (unlikely(!mm->context.tsb_block[MM_TSB_BASE].tsb))
 576                 return -ENOMEM;
 577
 578         return 0;
 579 }
 580
 581 static void tsb_destroy_one(struct tsb_config *tp)
 582 {
 583         unsigned long cache_index;
 584
 585         if (!tp->tsb)
 586                 return;
 587         cache_index = tp->tsb_reg_val & 0x7UL;
 588         kmem_cache_free(tsb_caches[cache_index], tp->tsb);
 589         tp->tsb = NULL;
 590         tp->tsb_reg_val = 0UL;
 591 }
 592
 593 void destroy_context(struct mm_struct *mm)
 594 {
 595         unsigned long flags, i;
 596
 597         for (i = 0; i < MM_NUM_TSBS; i++)
 598                 tsb_destroy_one(&mm->context.tsb_block[i]);
 599
 600         spin_lock_irqsave(&ctx_alloc_lock, flags);
 601
 602         if (CTX_VALID(mm->context)) {
 603                 unsigned long nr = CTX_NRBITS(mm->context);
 604                 mmu_context_bmap[nr>>6] &= ~(1UL << (nr & 63));
 605         }
 606
 607         spin_unlock_irqrestore(&ctx_alloc_lock, flags);
 608 }