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 <linux/mm_types.h>
  10
  11 #include <asm/page.h>
  12 #include <asm/pgtable.h>
  13 #include <asm/mmu_context.h>
  14 #include <asm/setup.h>
  15 #include <asm/tsb.h>
  16 #include <asm/tlb.h>
  17 #include <asm/oplib.h>
  18
  19 extern struct tsb swapper_tsb[KERNEL_TSB_NENTRIES];
  20
  21 static inline unsigned long tsb_hash(unsigned long vaddr, unsigned long hash_shift, unsigned long nentries)
  22 {
  23         vaddr >>= hash_shift;
  24         return vaddr & (nentries - 1);
  25 }
  26
  27 static inline int tag_compare(unsigned long tag, unsigned long vaddr)
  28 {
  29         return (tag == (vaddr >> 22));
  30 }
  31
  32 static void flush_tsb_kernel_range_scan(unsigned long start, unsigned long end)
  33 {
  34         unsigned long idx;
  35
  36         for (idx = 0; idx < KERNEL_TSB_NENTRIES; idx++) {
  37                 struct tsb *ent = &swapper_tsb[idx];
  38                 unsigned long match = idx << 13;
  39
  40                 match |= (ent->tag << 22);
  41                 if (match >= start && match < end)
  42                         ent->tag = (1UL << TSB_TAG_INVALID_BIT);
  43         }
  44 }
  45
  46 /* TSB flushes need only occur on the processor initiating the address
  47  * space modification, not on each cpu the address space has run on.
  48  * Only the TLB flush needs that treatment.
  49  */
  50
  51 void flush_tsb_kernel_range(unsigned long start, unsigned long end)
  52 {
  53         unsigned long v;
  54
  55         if ((end - start) >> PAGE_SHIFT >= 2 * KERNEL_TSB_NENTRIES)
  56                 return flush_tsb_kernel_range_scan(start, end);
  57
  58         for (v = start; v < end; v += PAGE_SIZE) {
  59                 unsigned long hash = tsb_hash(v, PAGE_SHIFT,
  60                                               KERNEL_TSB_NENTRIES);
  61                 struct tsb *ent = &swapper_tsb[hash];
  62
  63                 if (tag_compare(ent->tag, v))
  64                         ent->tag = (1UL << TSB_TAG_INVALID_BIT);
  65         }
  66 }
  67
  68 static void __flush_tsb_one_entry(unsigned long tsb, unsigned long v,
  69                                   unsigned long hash_shift,
  70                                   unsigned long nentries)
  71 {
  72         unsigned long tag, ent, hash;
  73
  74         v &= ~0x1UL;
  75         hash = tsb_hash(v, hash_shift, nentries);
  76         ent = tsb + (hash * sizeof(struct tsb));
  77         tag = (v >> 22UL);
  78
  79         tsb_flush(ent, tag);
  80 }
  81
  82 static void __flush_tsb_one(struct tlb_batch *tb, unsigned long hash_shift,
  83                             unsigned long tsb, unsigned long nentries)
  84 {
  85         unsigned long i;
  86
  87         for (i = 0; i < tb->tlb_nr; i++)
  88                 __flush_tsb_one_entry(tsb, tb->vaddrs[i], hash_shift, nentries);
  89 }
  90
  91 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
  92 static void __flush_huge_tsb_one_entry(unsigned long tsb, unsigned long v,
  93                                        unsigned long hash_shift,
  94                                        unsigned long nentries,
  95                                        unsigned int hugepage_shift)
  96 {
  97         unsigned int hpage_entries;
  98         unsigned int i;
  99
 100         hpage_entries = 1 << (hugepage_shift - hash_shift);
 101         for (i = 0; i < hpage_entries; i++)
 102                 __flush_tsb_one_entry(tsb, v + (i << hash_shift), hash_shift,
 103                                       nentries);
 104 }
 105
 106 static void __flush_huge_tsb_one(struct tlb_batch *tb, unsigned long hash_shift,
 107                                  unsigned long tsb, unsigned long nentries,
 108                                  unsigned int hugepage_shift)
 109 {
 110         unsigned long i;
 111
 112         for (i = 0; i < tb->tlb_nr; i++)
 113                 __flush_huge_tsb_one_entry(tsb, tb->vaddrs[i], hash_shift,
 114                                            nentries, hugepage_shift);
 115 }
 116 #endif
 117
 118 void flush_tsb_user(struct tlb_batch *tb)
 119 {
 120         struct mm_struct *mm = tb->mm;
 121         unsigned long nentries, base, flags;
 122
 123         spin_lock_irqsave(&mm->context.lock, flags);
 124
 125         if (tb->hugepage_shift < REAL_HPAGE_SHIFT) {
 126                 base = (unsigned long) mm->context.tsb_block[MM_TSB_BASE].tsb;
 127                 nentries = mm->context.tsb_block[MM_TSB_BASE].tsb_nentries;
 128                 if (tlb_type == cheetah_plus || tlb_type == hypervisor)
 129                         base = __pa(base);
 130                 if (tb->hugepage_shift == PAGE_SHIFT)
 131                         __flush_tsb_one(tb, PAGE_SHIFT, base, nentries);
 132 #if defined(CONFIG_HUGETLB_PAGE)
 133                 else
 134                         __flush_huge_tsb_one(tb, PAGE_SHIFT, base, nentries,
 135                                              tb->hugepage_shift);
 136 #endif
 137         }
 138 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
 139         else if (mm->context.tsb_block[MM_TSB_HUGE].tsb) {
 140                 base = (unsigned long) mm->context.tsb_block[MM_TSB_HUGE].tsb;
 141                 nentries = mm->context.tsb_block[MM_TSB_HUGE].tsb_nentries;
 142                 if (tlb_type == cheetah_plus || tlb_type == hypervisor)
 143                         base = __pa(base);
 144                 __flush_huge_tsb_one(tb, REAL_HPAGE_SHIFT, base, nentries,
 145                                      tb->hugepage_shift);
 146         }
 147 #endif
 148         spin_unlock_irqrestore(&mm->context.lock, flags);
 149 }
 150
 151 void flush_tsb_user_page(struct mm_struct *mm, unsigned long vaddr,
 152                          unsigned int hugepage_shift)
 153 {
 154         unsigned long nentries, base, flags;
 155
 156         spin_lock_irqsave(&mm->context.lock, flags);
 157
 158         if (hugepage_shift < REAL_HPAGE_SHIFT) {
 159                 base = (unsigned long) mm->context.tsb_block[MM_TSB_BASE].tsb;
 160                 nentries = mm->context.tsb_block[MM_TSB_BASE].tsb_nentries;
 161                 if (tlb_type == cheetah_plus || tlb_type == hypervisor)
 162                         base = __pa(base);
 163                 if (hugepage_shift == PAGE_SHIFT)
 164                         __flush_tsb_one_entry(base, vaddr, PAGE_SHIFT,
 165                                               nentries);
 166 #if defined(CONFIG_HUGETLB_PAGE)
 167                 else
 168                         __flush_huge_tsb_one_entry(base, vaddr, PAGE_SHIFT,
 169                                                    nentries, hugepage_shift);
 170 #endif
 171         }
 172 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
 173         else if (mm->context.tsb_block[MM_TSB_HUGE].tsb) {
 174                 base = (unsigned long) mm->context.tsb_block[MM_TSB_HUGE].tsb;
 175                 nentries = mm->context.tsb_block[MM_TSB_HUGE].tsb_nentries;
 176                 if (tlb_type == cheetah_plus || tlb_type == hypervisor)
 177                         base = __pa(base);
 178                 __flush_huge_tsb_one_entry(base, vaddr, REAL_HPAGE_SHIFT,
 179                                            nentries, hugepage_shift);
 180         }
 181 #endif
 182         spin_unlock_irqrestore(&mm->context.lock, flags);
 183 }
 184
 185 #define HV_PGSZ_IDX_BASE        HV_PGSZ_IDX_8K
 186 #define HV_PGSZ_MASK_BASE       HV_PGSZ_MASK_8K
 187
 188 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
 189 #define HV_PGSZ_IDX_HUGE        HV_PGSZ_IDX_4MB
 190 #define HV_PGSZ_MASK_HUGE       HV_PGSZ_MASK_4MB
 191 #endif
 192
 193 static void setup_tsb_params(struct mm_struct *mm, unsigned long tsb_idx, unsigned long tsb_bytes)
 194 {
 195         unsigned long tsb_reg, base, tsb_paddr;
 196         unsigned long page_sz, tte;
 197
 198         mm->context.tsb_block[tsb_idx].tsb_nentries =
 199                 tsb_bytes / sizeof(struct tsb);
 200
 201         switch (tsb_idx) {
 202         case MM_TSB_BASE:
 203                 base = TSBMAP_8K_BASE;
 204                 break;
 205 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
 206         case MM_TSB_HUGE:
 207                 base = TSBMAP_4M_BASE;
 208                 break;
 209 #endif
 210         default:
 211                 BUG();
 212         }
 213
 214         tte = pgprot_val(PAGE_KERNEL_LOCKED);
 215         tsb_paddr = __pa(mm->context.tsb_block[tsb_idx].tsb);
 216         BUG_ON(tsb_paddr & (tsb_bytes - 1UL));
 217
 218         /* Use the smallest page size that can map the whole TSB
 219          * in one TLB entry.
 220          */
 221         switch (tsb_bytes) {
 222         case 8192 << 0:
 223                 tsb_reg = 0x0UL;
 224 #ifdef DCACHE_ALIASING_POSSIBLE
 225                 base += (tsb_paddr & 8192);
 226 #endif
 227                 page_sz = 8192;
 228                 break;
 229
 230         case 8192 << 1:
 231                 tsb_reg = 0x1UL;
 232                 page_sz = 64 * 1024;
 233                 break;
 234
 235         case 8192 << 2:
 236                 tsb_reg = 0x2UL;
 237                 page_sz = 64 * 1024;
 238                 break;
 239
 240         case 8192 << 3:
 241                 tsb_reg = 0x3UL;
 242                 page_sz = 64 * 1024;
 243                 break;
 244
 245         case 8192 << 4:
 246                 tsb_reg = 0x4UL;
 247                 page_sz = 512 * 1024;
 248                 break;
 249
 250         case 8192 << 5:
 251                 tsb_reg = 0x5UL;
 252                 page_sz = 512 * 1024;
 253                 break;
 254
 255         case 8192 << 6:
 256                 tsb_reg = 0x6UL;
 257                 page_sz = 512 * 1024;
 258                 break;
 259
 260         case 8192 << 7:
 261                 tsb_reg = 0x7UL;
 262                 page_sz = 4 * 1024 * 1024;
 263                 break;
 264
 265         default:
 266                 printk(KERN_ERR "TSB[%s:%d]: Impossible TSB size %lu, killing process.\n",
 267                        current->comm, current->pid, tsb_bytes);
 268                 do_exit(SIGSEGV);
 269         }
 270         tte |= pte_sz_bits(page_sz);
 271
 272         if (tlb_type == cheetah_plus || tlb_type == hypervisor) {
 273                 /* Physical mapping, no locked TLB entry for TSB.  */
 274                 tsb_reg |= tsb_paddr;
 275
 276                 mm->context.tsb_block[tsb_idx].tsb_reg_val = tsb_reg;
 277                 mm->context.tsb_block[tsb_idx].tsb_map_vaddr = 0;
 278                 mm->context.tsb_block[tsb_idx].tsb_map_pte = 0;
 279         } else {
 280                 tsb_reg |= base;
 281                 tsb_reg |= (tsb_paddr & (page_sz - 1UL));
 282                 tte |= (tsb_paddr & ~(page_sz - 1UL));
 283
 284                 mm->context.tsb_block[tsb_idx].tsb_reg_val = tsb_reg;
 285                 mm->context.tsb_block[tsb_idx].tsb_map_vaddr = base;
 286                 mm->context.tsb_block[tsb_idx].tsb_map_pte = tte;
 287         }
 288
 289         /* Setup the Hypervisor TSB descriptor.  */
 290         if (tlb_type == hypervisor) {
 291                 struct hv_tsb_descr *hp = &mm->context.tsb_descr[tsb_idx];
 292
 293                 switch (tsb_idx) {
 294                 case MM_TSB_BASE:
 295                         hp->pgsz_idx = HV_PGSZ_IDX_BASE;
 296                         break;
 297 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
 298                 case MM_TSB_HUGE:
 299                         hp->pgsz_idx = HV_PGSZ_IDX_HUGE;
 300                         break;
 301 #endif
 302                 default:
 303                         BUG();
 304                 }
 305                 hp->assoc = 1;
 306                 hp->num_ttes = tsb_bytes / 16;
 307                 hp->ctx_idx = 0;
 308                 switch (tsb_idx) {
 309                 case MM_TSB_BASE:
 310                         hp->pgsz_mask = HV_PGSZ_MASK_BASE;
 311                         break;
 312 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
 313                 case MM_TSB_HUGE:
 314                         hp->pgsz_mask = HV_PGSZ_MASK_HUGE;
 315                         break;
 316 #endif
 317                 default:
 318                         BUG();
 319                 }
 320                 hp->tsb_base = tsb_paddr;
 321                 hp->resv = 0;
 322         }
 323 }
 324
 325 struct kmem_cache *pgtable_cache __read_mostly;
 326
 327 static struct kmem_cache *tsb_caches[8] __read_mostly;
 328
 329 static const char *tsb_cache_names[8] = {
 330         "tsb_8KB",
 331         "tsb_16KB",
 332         "tsb_32KB",
 333         "tsb_64KB",
 334         "tsb_128KB",
 335         "tsb_256KB",
 336         "tsb_512KB",
 337         "tsb_1MB",
 338 };
 339
 340 void __init pgtable_cache_init(void)
 341 {
 342         unsigned long i;
 343
 344         pgtable_cache = kmem_cache_create("pgtable_cache",
 345                                           PAGE_SIZE, PAGE_SIZE,
 346                                           0,
 347                                           _clear_page);
 348         if (!pgtable_cache) {
 349                 prom_printf("pgtable_cache_init(): Could not create!\n");
 350                 prom_halt();
 351         }
 352
 353         for (i = 0; i < ARRAY_SIZE(tsb_cache_names); i++) {
 354                 unsigned long size = 8192 << i;
 355                 const char *name = tsb_cache_names[i];
 356
 357                 tsb_caches[i] = kmem_cache_create(name,
 358                                                   size, size,
 359                                                   0, NULL);
 360                 if (!tsb_caches[i]) {
 361                         prom_printf("Could not create %s cache\n", name);
 362                         prom_halt();
 363                 }
 364         }
 365 }
 366
 367 int sysctl_tsb_ratio = -2;
 368
 369 static unsigned long tsb_size_to_rss_limit(unsigned long new_size)
 370 {
 371         unsigned long num_ents = (new_size / sizeof(struct tsb));
 372
 373         if (sysctl_tsb_ratio < 0)
 374                 return num_ents - (num_ents >> -sysctl_tsb_ratio);
 375         else
 376                 return num_ents + (num_ents >> sysctl_tsb_ratio);
 377 }
 378
 379 /* When the RSS of an address space exceeds tsb_rss_limit for a TSB,
 380  * do_sparc64_fault() invokes this routine to try and grow it.
 381  *
 382  * When we reach the maximum TSB size supported, we stick ~0UL into
 383  * tsb_rss_limit for that TSB so the grow checks in do_sparc64_fault()
 384  * will not trigger any longer.
 385  *
 386  * The TSB can be anywhere from 8K to 1MB in size, in increasing powers
 387  * of two.  The TSB must be aligned to it's size, so f.e. a 512K TSB
 388  * must be 512K aligned.  It also must be physically contiguous, so we
 389  * cannot use vmalloc().
 390  *
 391  * The idea here is to grow the TSB when the RSS of the process approaches
 392  * the number of entries that the current TSB can hold at once.  Currently,
 393  * we trigger when the RSS hits 3/4 of the TSB capacity.
 394  */
 395 void tsb_grow(struct mm_struct *mm, unsigned long tsb_index, unsigned long rss)
 396 {
 397         unsigned long max_tsb_size = 1 * 1024 * 1024;
 398         unsigned long new_size, old_size, flags;
 399         struct tsb *old_tsb, *new_tsb;
 400         unsigned long new_cache_index, old_cache_index;
 401         unsigned long new_rss_limit;
 402         gfp_t gfp_flags;
 403
 404         if (max_tsb_size > (PAGE_SIZE << MAX_ORDER))
 405                 max_tsb_size = (PAGE_SIZE << MAX_ORDER);
 406
 407         new_cache_index = 0;
 408         for (new_size = 8192; new_size < max_tsb_size; new_size <<= 1UL) {
 409                 new_rss_limit = tsb_size_to_rss_limit(new_size);
 410                 if (new_rss_limit > rss)
 411                         break;
 412                 new_cache_index++;
 413         }
 414
 415         if (new_size == max_tsb_size)
 416                 new_rss_limit = ~0UL;
 417
 418 retry_tsb_alloc:
 419         gfp_flags = GFP_KERNEL;
 420         if (new_size > (PAGE_SIZE * 2))
 421                 gfp_flags |= __GFP_NOWARN | __GFP_NORETRY;
 422
 423         new_tsb = kmem_cache_alloc_node(tsb_caches[new_cache_index],
 424                                         gfp_flags, numa_node_id());
 425         if (unlikely(!new_tsb)) {
 426                 /* Not being able to fork due to a high-order TSB
 427                  * allocation failure is very bad behavior.  Just back
 428                  * down to a 0-order allocation and force no TSB
 429                  * growing for this address space.
 430                  */
 431                 if (mm->context.tsb_block[tsb_index].tsb == NULL &&
 432                     new_cache_index > 0) {
 433                         new_cache_index = 0;
 434                         new_size = 8192;
 435                         new_rss_limit = ~0UL;
 436                         goto retry_tsb_alloc;
 437                 }
 438
 439                 /* If we failed on a TSB grow, we are under serious
 440                  * memory pressure so don't try to grow any more.
 441                  */
 442                 if (mm->context.tsb_block[tsb_index].tsb != NULL)
 443                         mm->context.tsb_block[tsb_index].tsb_rss_limit = ~0UL;
 444                 return;
 445         }
 446
 447         /* Mark all tags as invalid.  */
 448         tsb_init(new_tsb, new_size);
 449
 450         /* Ok, we are about to commit the changes.  If we are
 451          * growing an existing TSB the locking is very tricky,
 452          * so WATCH OUT!
 453          *
 454          * We have to hold mm->context.lock while committing to the
 455          * new TSB, this synchronizes us with processors in
 456          * flush_tsb_user() and switch_mm() for this address space.
 457          *
 458          * But even with that lock held, processors run asynchronously
 459          * accessing the old TSB via TLB miss handling.  This is OK
 460          * because those actions are just propagating state from the
 461          * Linux page tables into the TSB, page table mappings are not
 462          * being changed.  If a real fault occurs, the processor will
 463          * synchronize with us when it hits flush_tsb_user(), this is
 464          * also true for the case where vmscan is modifying the page
 465          * tables.  The only thing we need to be careful with is to
 466          * skip any locked TSB entries during copy_tsb().
 467          *
 468          * When we finish committing to the new TSB, we have to drop
 469          * the lock and ask all other cpus running this address space
 470          * to run tsb_context_switch() to see the new TSB table.
 471          */
 472         spin_lock_irqsave(&mm->context.lock, flags);
 473
 474         old_tsb = mm->context.tsb_block[tsb_index].tsb;
 475         old_cache_index =
 476                 (mm->context.tsb_block[tsb_index].tsb_reg_val & 0x7UL);
 477         old_size = (mm->context.tsb_block[tsb_index].tsb_nentries *
 478                     sizeof(struct tsb));
 479
 480
 481         /* Handle multiple threads trying to grow the TSB at the same time.
 482          * One will get in here first, and bump the size and the RSS limit.
 483          * The others will get in here next and hit this check.
 484          */
 485         if (unlikely(old_tsb &&
 486                      (rss < mm->context.tsb_block[tsb_index].tsb_rss_limit))) {
 487                 spin_unlock_irqrestore(&mm->context.lock, flags);
 488
 489                 kmem_cache_free(tsb_caches[new_cache_index], new_tsb);
 490                 return;
 491         }
 492
 493         mm->context.tsb_block[tsb_index].tsb_rss_limit = new_rss_limit;
 494
 495         if (old_tsb) {
 496                 extern void copy_tsb(unsigned long old_tsb_base,
 497                                      unsigned long old_tsb_size,
 498                                      unsigned long new_tsb_base,
 499                                      unsigned long new_tsb_size);
 500                 unsigned long old_tsb_base = (unsigned long) old_tsb;
 501                 unsigned long new_tsb_base = (unsigned long) new_tsb;
 502
 503                 if (tlb_type == cheetah_plus || tlb_type == hypervisor) {
 504                         old_tsb_base = __pa(old_tsb_base);
 505                         new_tsb_base = __pa(new_tsb_base);
 506                 }
 507                 copy_tsb(old_tsb_base, old_size, new_tsb_base, new_size);
 508         }
 509
 510         mm->context.tsb_block[tsb_index].tsb = new_tsb;
 511         setup_tsb_params(mm, tsb_index, new_size);
 512
 513         spin_unlock_irqrestore(&mm->context.lock, flags);
 514
 515         /* If old_tsb is NULL, we're being invoked for the first time
 516          * from init_new_context().
 517          */
 518         if (old_tsb) {
 519                 /* Reload it on the local cpu.  */
 520                 tsb_context_switch(mm);
 521
 522                 /* Now force other processors to do the same.  */
 523                 preempt_disable();
 524                 smp_tsb_sync(mm);
 525                 preempt_enable();
 526
 527                 /* Now it is safe to free the old tsb.  */
 528                 kmem_cache_free(tsb_caches[old_cache_index], old_tsb);
 529         }
 530 }
 531
 532 int init_new_context(struct task_struct *tsk, struct mm_struct *mm)
 533 {
 534         unsigned long mm_rss = get_mm_rss(mm);
 535 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
 536         unsigned long saved_hugetlb_pte_count;
 537         unsigned long saved_thp_pte_count;
 538 #endif
 539         unsigned int i;
 540
 541         spin_lock_init(&mm->context.lock);
 542
 543         mm->context.sparc64_ctx_val = 0UL;
 544
 545 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
 546         /* We reset them to zero because the fork() page copying
 547          * will re-increment the counters as the parent PTEs are
 548          * copied into the child address space.
 549          */
 550         saved_hugetlb_pte_count = mm->context.hugetlb_pte_count;
 551         saved_thp_pte_count = mm->context.thp_pte_count;
 552         mm->context.hugetlb_pte_count = 0;
 553         mm->context.thp_pte_count = 0;
 554
 555         mm_rss -= saved_thp_pte_count * (HPAGE_SIZE / PAGE_SIZE);
 556 #endif
 557
 558         /* copy_mm() copies over the parent's mm_struct before calling
 559          * us, so we need to zero out the TSB pointer or else tsb_grow()
 560          * will be confused and think there is an older TSB to free up.
 561          */
 562         for (i = 0; i < MM_NUM_TSBS; i++)
 563                 mm->context.tsb_block[i].tsb = NULL;
 564
 565         /* If this is fork, inherit the parent's TSB size.  We would
 566          * grow it to that size on the first page fault anyways.
 567          */
 568         tsb_grow(mm, MM_TSB_BASE, mm_rss);
 569
 570 #if defined(CONFIG_HUGETLB_PAGE) || defined(CONFIG_TRANSPARENT_HUGEPAGE)
 571         if (unlikely(saved_hugetlb_pte_count + saved_thp_pte_count))
 572                 tsb_grow(mm, MM_TSB_HUGE,
 573                          (saved_hugetlb_pte_count + saved_thp_pte_count) *
 574                          REAL_HPAGE_PER_HPAGE);
 575 #endif
 576
 577         if (unlikely(!mm->context.tsb_block[MM_TSB_BASE].tsb))
 578                 return -ENOMEM;
 579
 580         return 0;
 581 }
 582
 583 static void tsb_destroy_one(struct tsb_config *tp)
 584 {
 585         unsigned long cache_index;
 586
 587         if (!tp->tsb)
 588                 return;
 589         cache_index = tp->tsb_reg_val & 0x7UL;
 590         kmem_cache_free(tsb_caches[cache_index], tp->tsb);
 591         tp->tsb = NULL;
 592         tp->tsb_reg_val = 0UL;
 593 }
 594
 595 void destroy_context(struct mm_struct *mm)
 596 {
 597         unsigned long flags, i;
 598
 599         for (i = 0; i < MM_NUM_TSBS; i++)
 600                 tsb_destroy_one(&mm->context.tsb_block[i]);
 601
 602         spin_lock_irqsave(&ctx_alloc_lock, flags);
 603
 604         if (CTX_VALID(mm->context)) {
 605                 unsigned long nr = CTX_NRBITS(mm->context);
 606                 mmu_context_bmap[nr>>6] &= ~(1UL << (nr & 63));
 607         }
 608
 609         spin_unlock_irqrestore(&ctx_alloc_lock, flags);
 610 }