lib/dma-debug.c

   1 /*
   2  * Copyright (C) 2008 Advanced Micro Devices, Inc.
   3  *
   4  * Author: Joerg Roedel <joerg.roedel@amd.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License version 2 as published
   8  * by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  18  */
  19
  20 #include <linux/scatterlist.h>
  21 #include <linux/dma-mapping.h>
  22 #include <linux/stacktrace.h>
  23 #include <linux/dma-debug.h>
  24 #include <linux/spinlock.h>
  25 #include <linux/debugfs.h>
  26 #include <linux/uaccess.h>
  27 #include <linux/export.h>
  28 #include <linux/device.h>
  29 #include <linux/types.h>
  30 #include <linux/sched.h>
  31 #include <linux/ctype.h>
  32 #include <linux/list.h>
  33 #include <linux/slab.h>
  34
  35 #include <asm/sections.h>
  36
  37 #define HASH_SIZE       1024ULL
  38 #define HASH_FN_SHIFT   13
  39 #define HASH_FN_MASK    (HASH_SIZE - 1)
  40
  41 enum {
  42         dma_debug_single,
  43         dma_debug_page,
  44         dma_debug_sg,
  45         dma_debug_coherent,
  46 };
  47
  48 enum map_err_types {
  49         MAP_ERR_CHECK_NOT_APPLICABLE,
  50         MAP_ERR_NOT_CHECKED,
  51         MAP_ERR_CHECKED,
  52 };
  53
  54 #define DMA_DEBUG_STACKTRACE_ENTRIES 5
  55
  56 /**
  57  * struct dma_debug_entry - track a dma_map* or dma_alloc_coherent mapping
  58  * @list: node on pre-allocated free_entries list
  59  * @dev: 'dev' argument to dma_map_{page|single|sg} or dma_alloc_coherent
  60  * @type: single, page, sg, coherent
  61  * @pfn: page frame of the start address
  62  * @offset: offset of mapping relative to pfn
  63  * @size: length of the mapping
  64  * @direction: enum dma_data_direction
  65  * @sg_call_ents: 'nents' from dma_map_sg
  66  * @sg_mapped_ents: 'mapped_ents' from dma_map_sg
  67  * @map_err_type: track whether dma_mapping_error() was checked
  68  * @stacktrace: support backtraces when a violation is detected
  69  */
  70 struct dma_debug_entry {
  71         struct list_head list;
  72         struct device    *dev;
  73         int              type;
  74         unsigned long    pfn;
  75         size_t           offset;
  76         u64              dev_addr;
  77         u64              size;
  78         int              direction;
  79         int              sg_call_ents;
  80         int              sg_mapped_ents;
  81         enum map_err_types  map_err_type;
  82 #ifdef CONFIG_STACKTRACE
  83         struct           stack_trace stacktrace;
  84         unsigned long    st_entries[DMA_DEBUG_STACKTRACE_ENTRIES];
  85 #endif
  86 };
  87
  88 typedef bool (*match_fn)(struct dma_debug_entry *, struct dma_debug_entry *);
  89
  90 struct hash_bucket {
  91         struct list_head list;
  92         spinlock_t lock;
  93 } ____cacheline_aligned_in_smp;
  94
  95 /* Hash list to save the allocated dma addresses */
  96 static struct hash_bucket dma_entry_hash[HASH_SIZE];
  97 /* List of pre-allocated dma_debug_entry's */
  98 static LIST_HEAD(free_entries);
  99 /* Lock for the list above */
 100 static DEFINE_SPINLOCK(free_entries_lock);
 101
 102 /* Global disable flag - will be set in case of an error */
 103 static u32 global_disable __read_mostly;
 104
 105 /* Global error count */
 106 static u32 error_count;
 107
 108 /* Global error show enable*/
 109 static u32 show_all_errors __read_mostly;
 110 /* Number of errors to show */
 111 static u32 show_num_errors = 1;
 112
 113 static u32 num_free_entries;
 114 static u32 min_free_entries;
 115 static u32 nr_total_entries;
 116
 117 /* number of preallocated entries requested by kernel cmdline */
 118 static u32 req_entries;
 119
 120 /* debugfs dentry's for the stuff above */
 121 static struct dentry *dma_debug_dent        __read_mostly;
 122 static struct dentry *global_disable_dent   __read_mostly;
 123 static struct dentry *error_count_dent      __read_mostly;
 124 static struct dentry *show_all_errors_dent  __read_mostly;
 125 static struct dentry *show_num_errors_dent  __read_mostly;
 126 static struct dentry *num_free_entries_dent __read_mostly;
 127 static struct dentry *min_free_entries_dent __read_mostly;
 128 static struct dentry *filter_dent           __read_mostly;
 129
 130 /* per-driver filter related state */
 131
 132 #define NAME_MAX_LEN    64
 133
 134 static char                  current_driver_name[NAME_MAX_LEN] __read_mostly;
 135 static struct device_driver *current_driver                    __read_mostly;
 136
 137 static DEFINE_RWLOCK(driver_name_lock);
 138
 139 static const char *const maperr2str[] = {
 140         [MAP_ERR_CHECK_NOT_APPLICABLE] = "dma map error check not applicable",
 141         [MAP_ERR_NOT_CHECKED] = "dma map error not checked",
 142         [MAP_ERR_CHECKED] = "dma map error checked",
 143 };
 144
 145 static const char *type2name[4] = { "single", "page",
 146                                     "scather-gather", "coherent" };
 147
 148 static const char *dir2name[4] = { "DMA_BIDIRECTIONAL", "DMA_TO_DEVICE",
 149                                    "DMA_FROM_DEVICE", "DMA_NONE" };
 150
 151 /*
 152  * The access to some variables in this macro is racy. We can't use atomic_t
 153  * here because all these variables are exported to debugfs. Some of them even
 154  * writeable. This is also the reason why a lock won't help much. But anyway,
 155  * the races are no big deal. Here is why:
 156  *
 157  *   error_count: the addition is racy, but the worst thing that can happen is
 158  *                that we don't count some errors
 159  *   show_num_errors: the subtraction is racy. Also no big deal because in
 160  *                    worst case this will result in one warning more in the
 161  *                    system log than the user configured. This variable is
 162  *                    writeable via debugfs.
 163  */
 164 static inline void dump_entry_trace(struct dma_debug_entry *entry)
 165 {
 166 #ifdef CONFIG_STACKTRACE
 167         if (entry) {
 168                 pr_warning("Mapped at:\n");
 169                 print_stack_trace(&entry->stacktrace, 0);
 170         }
 171 #endif
 172 }
 173
 174 static bool driver_filter(struct device *dev)
 175 {
 176         struct device_driver *drv;
 177         unsigned long flags;
 178         bool ret;
 179
 180         /* driver filter off */
 181         if (likely(!current_driver_name[0]))
 182                 return true;
 183
 184         /* driver filter on and initialized */
 185         if (current_driver && dev && dev->driver == current_driver)
 186                 return true;
 187
 188         /* driver filter on, but we can't filter on a NULL device... */
 189         if (!dev)
 190                 return false;
 191
 192         if (current_driver || !current_driver_name[0])
 193                 return false;
 194
 195         /* driver filter on but not yet initialized */
 196         drv = dev->driver;
 197         if (!drv)
 198                 return false;
 199
 200         /* lock to protect against change of current_driver_name */
 201         read_lock_irqsave(&driver_name_lock, flags);
 202
 203         ret = false;
 204         if (drv->name &&
 205             strncmp(current_driver_name, drv->name, NAME_MAX_LEN - 1) == 0) {
 206                 current_driver = drv;
 207                 ret = true;
 208         }
 209
 210         read_unlock_irqrestore(&driver_name_lock, flags);
 211
 212         return ret;
 213 }
 214
 215 #define err_printk(dev, entry, format, arg...) do {                     \
 216                 error_count += 1;                                       \
 217                 if (driver_filter(dev) &&                               \
 218                     (show_all_errors || show_num_errors > 0)) {         \
 219                         WARN(1, "%s %s: " format,                       \
 220                              dev ? dev_driver_string(dev) : "NULL",     \
 221                              dev ? dev_name(dev) : "NULL", ## arg);     \
 222                         dump_entry_trace(entry);                        \
 223                 }                                                       \
 224                 if (!show_all_errors && show_num_errors > 0)            \
 225                         show_num_errors -= 1;                           \
 226         } while (0);
 227
 228 /*
 229  * Hash related functions
 230  *
 231  * Every DMA-API request is saved into a struct dma_debug_entry. To
 232  * have quick access to these structs they are stored into a hash.
 233  */
 234 static int hash_fn(struct dma_debug_entry *entry)
 235 {
 236         /*
 237          * Hash function is based on the dma address.
 238          * We use bits 20-27 here as the index into the hash
 239          */
 240         return (entry->dev_addr >> HASH_FN_SHIFT) & HASH_FN_MASK;
 241 }
 242
 243 /*
 244  * Request exclusive access to a hash bucket for a given dma_debug_entry.
 245  */
 246 static struct hash_bucket *get_hash_bucket(struct dma_debug_entry *entry,
 247                                            unsigned long *flags)
 248 {
 249         int idx = hash_fn(entry);
 250         unsigned long __flags;
 251
 252         spin_lock_irqsave(&dma_entry_hash[idx].lock, __flags);
 253         *flags = __flags;
 254         return &dma_entry_hash[idx];
 255 }
 256
 257 /*
 258  * Give up exclusive access to the hash bucket
 259  */
 260 static void put_hash_bucket(struct hash_bucket *bucket,
 261                             unsigned long *flags)
 262 {
 263         unsigned long __flags = *flags;
 264
 265         spin_unlock_irqrestore(&bucket->lock, __flags);
 266 }
 267
 268 static bool exact_match(struct dma_debug_entry *a, struct dma_debug_entry *b)
 269 {
 270         return ((a->dev_addr == b->dev_addr) &&
 271                 (a->dev == b->dev)) ? true : false;
 272 }
 273
 274 static bool containing_match(struct dma_debug_entry *a,
 275                              struct dma_debug_entry *b)
 276 {
 277         if (a->dev != b->dev)
 278                 return false;
 279
 280         if ((b->dev_addr <= a->dev_addr) &&
 281             ((b->dev_addr + b->size) >= (a->dev_addr + a->size)))
 282                 return true;
 283
 284         return false;
 285 }
 286
 287 /*
 288  * Search a given entry in the hash bucket list
 289  */
 290 static struct dma_debug_entry *__hash_bucket_find(struct hash_bucket *bucket,
 291                                                   struct dma_debug_entry *ref,
 292                                                   match_fn match)
 293 {
 294         struct dma_debug_entry *entry, *ret = NULL;
 295         int matches = 0, match_lvl, last_lvl = -1;
 296
 297         list_for_each_entry(entry, &bucket->list, list) {
 298                 if (!match(ref, entry))
 299                         continue;
 300
 301                 /*
 302                  * Some drivers map the same physical address multiple
 303                  * times. Without a hardware IOMMU this results in the
 304                  * same device addresses being put into the dma-debug
 305                  * hash multiple times too. This can result in false
 306                  * positives being reported. Therefore we implement a
 307                  * best-fit algorithm here which returns the entry from
 308                  * the hash which fits best to the reference value
 309                  * instead of the first-fit.
 310                  */
 311                 matches += 1;
 312                 match_lvl = 0;
 313                 entry->size         == ref->size         ? ++match_lvl : 0;
 314                 entry->type         == ref->type         ? ++match_lvl : 0;
 315                 entry->direction    == ref->direction    ? ++match_lvl : 0;
 316                 entry->sg_call_ents == ref->sg_call_ents ? ++match_lvl : 0;
 317
 318                 if (match_lvl == 4) {
 319                         /* perfect-fit - return the result */
 320                         return entry;
 321                 } else if (match_lvl > last_lvl) {
 322                         /*
 323                          * We found an entry that fits better then the
 324                          * previous one or it is the 1st match.
 325                          */
 326                         last_lvl = match_lvl;
 327                         ret      = entry;
 328                 }
 329         }
 330
 331         /*
 332          * If we have multiple matches but no perfect-fit, just return
 333          * NULL.
 334          */
 335         ret = (matches == 1) ? ret : NULL;
 336
 337         return ret;
 338 }
 339
 340 static struct dma_debug_entry *bucket_find_exact(struct hash_bucket *bucket,
 341                                                  struct dma_debug_entry *ref)
 342 {
 343         return __hash_bucket_find(bucket, ref, exact_match);
 344 }
 345
 346 static struct dma_debug_entry *bucket_find_contain(struct hash_bucket **bucket,
 347                                                    struct dma_debug_entry *ref,
 348                                                    unsigned long *flags)
 349 {
 350
 351         unsigned int max_range = dma_get_max_seg_size(ref->dev);
 352         struct dma_debug_entry *entry, index = *ref;
 353         unsigned int range = 0;
 354
 355         while (range <= max_range) {
 356                 entry = __hash_bucket_find(*bucket, &index, containing_match);
 357
 358                 if (entry)
 359                         return entry;
 360
 361                 /*
 362                  * Nothing found, go back a hash bucket
 363                  */
 364                 put_hash_bucket(*bucket, flags);
 365                 range          += (1 << HASH_FN_SHIFT);
 366                 index.dev_addr -= (1 << HASH_FN_SHIFT);
 367                 *bucket = get_hash_bucket(&index, flags);
 368         }
 369
 370         return NULL;
 371 }
 372
 373 /*
 374  * Add an entry to a hash bucket
 375  */
 376 static void hash_bucket_add(struct hash_bucket *bucket,
 377                             struct dma_debug_entry *entry)
 378 {
 379         list_add_tail(&entry->list, &bucket->list);
 380 }
 381
 382 /*
 383  * Remove entry from a hash bucket list
 384  */
 385 static void hash_bucket_del(struct dma_debug_entry *entry)
 386 {
 387         list_del(&entry->list);
 388 }
 389
 390 static unsigned long long phys_addr(struct dma_debug_entry *entry)
 391 {
 392         return page_to_phys(pfn_to_page(entry->pfn)) + entry->offset;
 393 }
 394
 395 /*
 396  * Dump mapping entries for debugging purposes
 397  */
 398 void debug_dma_dump_mappings(struct device *dev)
 399 {
 400         int idx;
 401
 402         for (idx = 0; idx < HASH_SIZE; idx++) {
 403                 struct hash_bucket *bucket = &dma_entry_hash[idx];
 404                 struct dma_debug_entry *entry;
 405                 unsigned long flags;
 406
 407                 spin_lock_irqsave(&bucket->lock, flags);
 408
 409                 list_for_each_entry(entry, &bucket->list, list) {
 410                         if (!dev || dev == entry->dev) {
 411                                 dev_info(entry->dev,
 412                                          "%s idx %d P=%Lx N=%lx D=%Lx L=%Lx %s %s\n",
 413                                          type2name[entry->type], idx,
 414                                          phys_addr(entry), entry->pfn,
 415                                          entry->dev_addr, entry->size,
 416                                          dir2name[entry->direction],
 417                                          maperr2str[entry->map_err_type]);
 418                         }
 419                 }
 420
 421                 spin_unlock_irqrestore(&bucket->lock, flags);
 422         }
 423 }
 424 EXPORT_SYMBOL(debug_dma_dump_mappings);
 425
 426 /*
 427  * For each mapping (initial cacheline in the case of
 428  * dma_alloc_coherent/dma_map_page, initial cacheline in each page of a
 429  * scatterlist, or the cacheline specified in dma_map_single) insert
 430  * into this tree using the cacheline as the key. At
 431  * dma_unmap_{single|sg|page} or dma_free_coherent delete the entry.  If
 432  * the entry already exists at insertion time add a tag as a reference
 433  * count for the overlapping mappings.  For now, the overlap tracking
 434  * just ensures that 'unmaps' balance 'maps' before marking the
 435  * cacheline idle, but we should also be flagging overlaps as an API
 436  * violation.
 437  *
 438  * Memory usage is mostly constrained by the maximum number of available
 439  * dma-debug entries in that we need a free dma_debug_entry before
 440  * inserting into the tree.  In the case of dma_map_page and
 441  * dma_alloc_coherent there is only one dma_debug_entry and one
 442  * dma_active_cacheline entry to track per event.  dma_map_sg(), on the
 443  * other hand, consumes a single dma_debug_entry, but inserts 'nents'
 444  * entries into the tree.
 445  *
 446  * At any time debug_dma_assert_idle() can be called to trigger a
 447  * warning if any cachelines in the given page are in the active set.
 448  */
 449 static RADIX_TREE(dma_active_cacheline, GFP_NOWAIT);
 450 static DEFINE_SPINLOCK(radix_lock);
 451 #define ACTIVE_CACHELINE_MAX_OVERLAP ((1 << RADIX_TREE_MAX_TAGS) - 1)
 452 #define CACHELINE_PER_PAGE_SHIFT (PAGE_SHIFT - L1_CACHE_SHIFT)
 453 #define CACHELINES_PER_PAGE (1 << CACHELINE_PER_PAGE_SHIFT)
 454
 455 static phys_addr_t to_cacheline_number(struct dma_debug_entry *entry)
 456 {
 457         return (entry->pfn << CACHELINE_PER_PAGE_SHIFT) +
 458                 (entry->offset >> L1_CACHE_SHIFT);
 459 }
 460
 461 static int active_cacheline_read_overlap(phys_addr_t cln)
 462 {
 463         int overlap = 0, i;
 464
 465         for (i = RADIX_TREE_MAX_TAGS - 1; i >= 0; i--)
 466                 if (radix_tree_tag_get(&dma_active_cacheline, cln, i))
 467                         overlap |= 1 << i;
 468         return overlap;
 469 }
 470
 471 static int active_cacheline_set_overlap(phys_addr_t cln, int overlap)
 472 {
 473         int i;
 474
 475         if (overlap > ACTIVE_CACHELINE_MAX_OVERLAP || overlap < 0)
 476                 return overlap;
 477
 478         for (i = RADIX_TREE_MAX_TAGS - 1; i >= 0; i--)
 479                 if (overlap & 1 << i)
 480                         radix_tree_tag_set(&dma_active_cacheline, cln, i);
 481                 else
 482                         radix_tree_tag_clear(&dma_active_cacheline, cln, i);
 483
 484         return overlap;
 485 }
 486
 487 static void active_cacheline_inc_overlap(phys_addr_t cln)
 488 {
 489         int overlap = active_cacheline_read_overlap(cln);
 490
 491         overlap = active_cacheline_set_overlap(cln, ++overlap);
 492
 493         /* If we overflowed the overlap counter then we're potentially
 494          * leaking dma-mappings.  Otherwise, if maps and unmaps are
 495          * balanced then this overflow may cause false negatives in
 496          * debug_dma_assert_idle() as the cacheline may be marked idle
 497          * prematurely.
 498          */
 499         WARN_ONCE(overlap > ACTIVE_CACHELINE_MAX_OVERLAP,
 500                   "DMA-API: exceeded %d overlapping mappings of cacheline %pa\n",
 501                   ACTIVE_CACHELINE_MAX_OVERLAP, &cln);
 502 }
 503
 504 static int active_cacheline_dec_overlap(phys_addr_t cln)
 505 {
 506         int overlap = active_cacheline_read_overlap(cln);
 507
 508         return active_cacheline_set_overlap(cln, --overlap);
 509 }
 510
 511 static int active_cacheline_insert(struct dma_debug_entry *entry)
 512 {
 513         phys_addr_t cln = to_cacheline_number(entry);
 514         unsigned long flags;
 515         int rc;
 516
 517         /* If the device is not writing memory then we don't have any
 518          * concerns about the cpu consuming stale data.  This mitigates
 519          * legitimate usages of overlapping mappings.
 520          */
 521         if (entry->direction == DMA_TO_DEVICE)
 522                 return 0;
 523
 524         spin_lock_irqsave(&radix_lock, flags);
 525         rc = radix_tree_insert(&dma_active_cacheline, cln, entry);
 526         if (rc == -EEXIST)
 527                 active_cacheline_inc_overlap(cln);
 528         spin_unlock_irqrestore(&radix_lock, flags);
 529
 530         return rc;
 531 }
 532
 533 static void active_cacheline_remove(struct dma_debug_entry *entry)
 534 {
 535         phys_addr_t cln = to_cacheline_number(entry);
 536         unsigned long flags;
 537
 538         /* ...mirror the insert case */
 539         if (entry->direction == DMA_TO_DEVICE)
 540                 return;
 541
 542         spin_lock_irqsave(&radix_lock, flags);
 543         /* since we are counting overlaps the final put of the
 544          * cacheline will occur when the overlap count is 0.
 545          * active_cacheline_dec_overlap() returns -1 in that case
 546          */
 547         if (active_cacheline_dec_overlap(cln) < 0)
 548                 radix_tree_delete(&dma_active_cacheline, cln);
 549         spin_unlock_irqrestore(&radix_lock, flags);
 550 }
 551
 552 /**
 553  * debug_dma_assert_idle() - assert that a page is not undergoing dma
 554  * @page: page to lookup in the dma_active_cacheline tree
 555  *
 556  * Place a call to this routine in cases where the cpu touching the page
 557  * before the dma completes (page is dma_unmapped) will lead to data
 558  * corruption.
 559  */
 560 void debug_dma_assert_idle(struct page *page)
 561 {
 562         static struct dma_debug_entry *ents[CACHELINES_PER_PAGE];
 563         struct dma_debug_entry *entry = NULL;
 564         void **results = (void **) &ents;
 565         unsigned int nents, i;
 566         unsigned long flags;
 567         phys_addr_t cln;
 568
 569         if (!page)
 570                 return;
 571
 572         cln = (phys_addr_t) page_to_pfn(page) << CACHELINE_PER_PAGE_SHIFT;
 573         spin_lock_irqsave(&radix_lock, flags);
 574         nents = radix_tree_gang_lookup(&dma_active_cacheline, results, cln,
 575                                        CACHELINES_PER_PAGE);
 576         for (i = 0; i < nents; i++) {
 577                 phys_addr_t ent_cln = to_cacheline_number(ents[i]);
 578
 579                 if (ent_cln == cln) {
 580                         entry = ents[i];
 581                         break;
 582                 } else if (ent_cln >= cln + CACHELINES_PER_PAGE)
 583                         break;
 584         }
 585         spin_unlock_irqrestore(&radix_lock, flags);
 586
 587         if (!entry)
 588                 return;
 589
 590         cln = to_cacheline_number(entry);
 591         err_printk(entry->dev, entry,
 592                    "DMA-API: cpu touching an active dma mapped cacheline [cln=%pa]\n",
 593                    &cln);
 594 }
 595
 596 /*
 597  * Wrapper function for adding an entry to the hash.
 598  * This function takes care of locking itself.
 599  */
 600 static void add_dma_entry(struct dma_debug_entry *entry)
 601 {
 602         struct hash_bucket *bucket;
 603         unsigned long flags;
 604         int rc;
 605
 606         bucket = get_hash_bucket(entry, &flags);
 607         hash_bucket_add(bucket, entry);
 608         put_hash_bucket(bucket, &flags);
 609
 610         rc = active_cacheline_insert(entry);
 611         if (rc == -ENOMEM) {
 612                 pr_err("DMA-API: cacheline tracking ENOMEM, dma-debug disabled\n");
 613                 global_disable = true;
 614         }
 615
 616         /* TODO: report -EEXIST errors here as overlapping mappings are
 617          * not supported by the DMA API
 618          */
 619 }
 620
 621 static struct dma_debug_entry *__dma_entry_alloc(void)
 622 {
 623         struct dma_debug_entry *entry;
 624
 625         entry = list_entry(free_entries.next, struct dma_debug_entry, list);
 626         list_del(&entry->list);
 627         memset(entry, 0, sizeof(*entry));
 628
 629         num_free_entries -= 1;
 630         if (num_free_entries < min_free_entries)
 631                 min_free_entries = num_free_entries;
 632
 633         return entry;
 634 }
 635
 636 /* struct dma_entry allocator
 637  *
 638  * The next two functions implement the allocator for
 639  * struct dma_debug_entries.
 640  */
 641 static struct dma_debug_entry *dma_entry_alloc(void)
 642 {
 643         struct dma_debug_entry *entry;
 644         unsigned long flags;
 645
 646         spin_lock_irqsave(&free_entries_lock, flags);
 647
 648         if (list_empty(&free_entries)) {
 649                 pr_err("DMA-API: debugging out of memory - disabling\n");
 650                 global_disable = true;
 651                 spin_unlock_irqrestore(&free_entries_lock, flags);
 652                 return NULL;
 653         }
 654
 655         entry = __dma_entry_alloc();
 656
 657         spin_unlock_irqrestore(&free_entries_lock, flags);
 658
 659 #ifdef CONFIG_STACKTRACE
 660         entry->stacktrace.max_entries = DMA_DEBUG_STACKTRACE_ENTRIES;
 661         entry->stacktrace.entries = entry->st_entries;
 662         entry->stacktrace.skip = 2;
 663         save_stack_trace(&entry->stacktrace);
 664 #endif
 665
 666         return entry;
 667 }
 668
 669 static void dma_entry_free(struct dma_debug_entry *entry)
 670 {
 671         unsigned long flags;
 672
 673         active_cacheline_remove(entry);
 674
 675         /*
 676          * add to beginning of the list - this way the entries are
 677          * more likely cache hot when they are reallocated.
 678          */
 679         spin_lock_irqsave(&free_entries_lock, flags);
 680         list_add(&entry->list, &free_entries);
 681         num_free_entries += 1;
 682         spin_unlock_irqrestore(&free_entries_lock, flags);
 683 }
 684
 685 int dma_debug_resize_entries(u32 num_entries)
 686 {
 687         int i, delta, ret = 0;
 688         unsigned long flags;
 689         struct dma_debug_entry *entry;
 690         LIST_HEAD(tmp);
 691
 692         spin_lock_irqsave(&free_entries_lock, flags);
 693
 694         if (nr_total_entries < num_entries) {
 695                 delta = num_entries - nr_total_entries;
 696
 697                 spin_unlock_irqrestore(&free_entries_lock, flags);
 698
 699                 for (i = 0; i < delta; i++) {
 700                         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 701                         if (!entry)
 702                                 break;
 703
 704                         list_add_tail(&entry->list, &tmp);
 705                 }
 706
 707                 spin_lock_irqsave(&free_entries_lock, flags);
 708
 709                 list_splice(&tmp, &free_entries);
 710                 nr_total_entries += i;
 711                 num_free_entries += i;
 712         } else {
 713                 delta = nr_total_entries - num_entries;
 714
 715                 for (i = 0; i < delta && !list_empty(&free_entries); i++) {
 716                         entry = __dma_entry_alloc();
 717                         kfree(entry);
 718                 }
 719
 720                 nr_total_entries -= i;
 721         }
 722
 723         if (nr_total_entries != num_entries)
 724                 ret = 1;
 725
 726         spin_unlock_irqrestore(&free_entries_lock, flags);
 727
 728         return ret;
 729 }
 730 EXPORT_SYMBOL(dma_debug_resize_entries);
 731
 732 /*
 733  * DMA-API debugging init code
 734  *
 735  * The init code does two things:
 736  *   1. Initialize core data structures
 737  *   2. Preallocate a given number of dma_debug_entry structs
 738  */
 739
 740 static int prealloc_memory(u32 num_entries)
 741 {
 742         struct dma_debug_entry *entry, *next_entry;
 743         int i;
 744
 745         for (i = 0; i < num_entries; ++i) {
 746                 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 747                 if (!entry)
 748                         goto out_err;
 749
 750                 list_add_tail(&entry->list, &free_entries);
 751         }
 752
 753         num_free_entries = num_entries;
 754         min_free_entries = num_entries;
 755
 756         pr_info("DMA-API: preallocated %d debug entries\n", num_entries);
 757
 758         return 0;
 759
 760 out_err:
 761
 762         list_for_each_entry_safe(entry, next_entry, &free_entries, list) {
 763                 list_del(&entry->list);
 764                 kfree(entry);
 765         }
 766
 767         return -ENOMEM;
 768 }
 769
 770 static ssize_t filter_read(struct file *file, char __user *user_buf,
 771                            size_t count, loff_t *ppos)
 772 {
 773         char buf[NAME_MAX_LEN + 1];
 774         unsigned long flags;
 775         int len;
 776
 777         if (!current_driver_name[0])
 778                 return 0;
 779
 780         /*
 781          * We can't copy to userspace directly because current_driver_name can
 782          * only be read under the driver_name_lock with irqs disabled. So
 783          * create a temporary copy first.
 784          */
 785         read_lock_irqsave(&driver_name_lock, flags);
 786         len = scnprintf(buf, NAME_MAX_LEN + 1, "%s\n", current_driver_name);
 787         read_unlock_irqrestore(&driver_name_lock, flags);
 788
 789         return simple_read_from_buffer(user_buf, count, ppos, buf, len);
 790 }
 791
 792 static ssize_t filter_write(struct file *file, const char __user *userbuf,
 793                             size_t count, loff_t *ppos)
 794 {
 795         char buf[NAME_MAX_LEN];
 796         unsigned long flags;
 797         size_t len;
 798         int i;
 799
 800         /*
 801          * We can't copy from userspace directly. Access to
 802          * current_driver_name is protected with a write_lock with irqs
 803          * disabled. Since copy_from_user can fault and may sleep we
 804          * need to copy to temporary buffer first
 805          */
 806         len = min(count, (size_t)(NAME_MAX_LEN - 1));
 807         if (copy_from_user(buf, userbuf, len))
 808                 return -EFAULT;
 809
 810         buf[len] = 0;
 811
 812         write_lock_irqsave(&driver_name_lock, flags);
 813
 814         /*
 815          * Now handle the string we got from userspace very carefully.
 816          * The rules are:
 817          *         - only use the first token we got
 818          *         - token delimiter is everything looking like a space
 819          *           character (' ', '\n', '\t' ...)
 820          *
 821          */
 822         if (!isalnum(buf[0])) {
 823                 /*
 824                  * If the first character userspace gave us is not
 825                  * alphanumerical then assume the filter should be
 826                  * switched off.
 827                  */
 828                 if (current_driver_name[0])
 829                         pr_info("DMA-API: switching off dma-debug driver filter\n");
 830                 current_driver_name[0] = 0;
 831                 current_driver = NULL;
 832                 goto out_unlock;
 833         }
 834
 835         /*
 836          * Now parse out the first token and use it as the name for the
 837          * driver to filter for.
 838          */
 839         for (i = 0; i < NAME_MAX_LEN - 1; ++i) {
 840                 current_driver_name[i] = buf[i];
 841                 if (isspace(buf[i]) || buf[i] == ' ' || buf[i] == 0)
 842                         break;
 843         }
 844         current_driver_name[i] = 0;
 845         current_driver = NULL;
 846
 847         pr_info("DMA-API: enable driver filter for driver [%s]\n",
 848                 current_driver_name);
 849
 850 out_unlock:
 851         write_unlock_irqrestore(&driver_name_lock, flags);
 852
 853         return count;
 854 }
 855
 856 static const struct file_operations filter_fops = {
 857         .read  = filter_read,
 858         .write = filter_write,
 859         .llseek = default_llseek,
 860 };
 861
 862 static int dma_debug_fs_init(void)
 863 {
 864         dma_debug_dent = debugfs_create_dir("dma-api", NULL);
 865         if (!dma_debug_dent) {
 866                 pr_err("DMA-API: can not create debugfs directory\n");
 867                 return -ENOMEM;
 868         }
 869
 870         global_disable_dent = debugfs_create_bool("disabled", 0444,
 871                         dma_debug_dent,
 872                         &global_disable);
 873         if (!global_disable_dent)
 874                 goto out_err;
 875
 876         error_count_dent = debugfs_create_u32("error_count", 0444,
 877                         dma_debug_dent, &error_count);
 878         if (!error_count_dent)
 879                 goto out_err;
 880
 881         show_all_errors_dent = debugfs_create_u32("all_errors", 0644,
 882                         dma_debug_dent,
 883                         &show_all_errors);
 884         if (!show_all_errors_dent)
 885                 goto out_err;
 886
 887         show_num_errors_dent = debugfs_create_u32("num_errors", 0644,
 888                         dma_debug_dent,
 889                         &show_num_errors);
 890         if (!show_num_errors_dent)
 891                 goto out_err;
 892
 893         num_free_entries_dent = debugfs_create_u32("num_free_entries", 0444,
 894                         dma_debug_dent,
 895                         &num_free_entries);
 896         if (!num_free_entries_dent)
 897                 goto out_err;
 898
 899         min_free_entries_dent = debugfs_create_u32("min_free_entries", 0444,
 900                         dma_debug_dent,
 901                         &min_free_entries);
 902         if (!min_free_entries_dent)
 903                 goto out_err;
 904
 905         filter_dent = debugfs_create_file("driver_filter", 0644,
 906                                           dma_debug_dent, NULL, &filter_fops);
 907         if (!filter_dent)
 908                 goto out_err;
 909
 910         return 0;
 911
 912 out_err:
 913         debugfs_remove_recursive(dma_debug_dent);
 914
 915         return -ENOMEM;
 916 }
 917
 918 static int device_dma_allocations(struct device *dev, struct dma_debug_entry **out_entry)
 919 {
 920         struct dma_debug_entry *entry;
 921         unsigned long flags;
 922         int count = 0, i;
 923
 924         local_irq_save(flags);
 925
 926         for (i = 0; i < HASH_SIZE; ++i) {
 927                 spin_lock(&dma_entry_hash[i].lock);
 928                 list_for_each_entry(entry, &dma_entry_hash[i].list, list) {
 929                         if (entry->dev == dev) {
 930                                 count += 1;
 931                                 *out_entry = entry;
 932                         }
 933                 }
 934                 spin_unlock(&dma_entry_hash[i].lock);
 935         }
 936
 937         local_irq_restore(flags);
 938
 939         return count;
 940 }
 941
 942 static int dma_debug_device_change(struct notifier_block *nb, unsigned long action, void *data)
 943 {
 944         struct device *dev = data;
 945         struct dma_debug_entry *uninitialized_var(entry);
 946         int count;
 947
 948         if (global_disable)
 949                 return 0;
 950
 951         switch (action) {
 952         case BUS_NOTIFY_UNBOUND_DRIVER:
 953                 count = device_dma_allocations(dev, &entry);
 954                 if (count == 0)
 955                         break;
 956                 err_printk(dev, entry, "DMA-API: device driver has pending "
 957                                 "DMA allocations while released from device "
 958                                 "[count=%d]\n"
 959                                 "One of leaked entries details: "
 960                                 "[device address=0x%016llx] [size=%llu bytes] "
 961                                 "[mapped with %s] [mapped as %s]\n",
 962                         count, entry->dev_addr, entry->size,
 963                         dir2name[entry->direction], type2name[entry->type]);
 964                 break;
 965         default:
 966                 break;
 967         }
 968
 969         return 0;
 970 }
 971
 972 void dma_debug_add_bus(struct bus_type *bus)
 973 {
 974         struct notifier_block *nb;
 975
 976         if (global_disable)
 977                 return;
 978
 979         nb = kzalloc(sizeof(struct notifier_block), GFP_KERNEL);
 980         if (nb == NULL) {
 981                 pr_err("dma_debug_add_bus: out of memory\n");
 982                 return;
 983         }
 984
 985         nb->notifier_call = dma_debug_device_change;
 986
 987         bus_register_notifier(bus, nb);
 988 }
 989
 990 /*
 991  * Let the architectures decide how many entries should be preallocated.
 992  */
 993 void dma_debug_init(u32 num_entries)
 994 {
 995         int i;
 996
 997         if (global_disable)
 998                 return;
 999
1000         for (i = 0; i < HASH_SIZE; ++i) {
1001                 INIT_LIST_HEAD(&dma_entry_hash[i].list);
1002                 spin_lock_init(&dma_entry_hash[i].lock);
1003         }
1004
1005         if (dma_debug_fs_init() != 0) {
1006                 pr_err("DMA-API: error creating debugfs entries - disabling\n");
1007                 global_disable = true;
1008
1009                 return;
1010         }
1011
1012         if (req_entries)
1013                 num_entries = req_entries;
1014
1015         if (prealloc_memory(num_entries) != 0) {
1016                 pr_err("DMA-API: debugging out of memory error - disabled\n");
1017                 global_disable = true;
1018
1019                 return;
1020         }
1021
1022         nr_total_entries = num_free_entries;
1023
1024         pr_info("DMA-API: debugging enabled by kernel config\n");
1025 }
1026
1027 static __init int dma_debug_cmdline(char *str)
1028 {
1029         if (!str)
1030                 return -EINVAL;
1031
1032         if (strncmp(str, "off", 3) == 0) {
1033                 pr_info("DMA-API: debugging disabled on kernel command line\n");
1034                 global_disable = true;
1035         }
1036
1037         return 0;
1038 }
1039
1040 static __init int dma_debug_entries_cmdline(char *str)
1041 {
1042         int res;
1043
1044         if (!str)
1045                 return -EINVAL;
1046
1047         res = get_option(&str, &req_entries);
1048
1049         if (!res)
1050                 req_entries = 0;
1051
1052         return 0;
1053 }
1054
1055 __setup("dma_debug=", dma_debug_cmdline);
1056 __setup("dma_debug_entries=", dma_debug_entries_cmdline);
1057
1058 static void check_unmap(struct dma_debug_entry *ref)
1059 {
1060         struct dma_debug_entry *entry;
1061         struct hash_bucket *bucket;
1062         unsigned long flags;
1063
1064         bucket = get_hash_bucket(ref, &flags);
1065         entry = bucket_find_exact(bucket, ref);
1066
1067         if (!entry) {
1068                 /* must drop lock before calling dma_mapping_error */
1069                 put_hash_bucket(bucket, &flags);
1070
1071                 if (dma_mapping_error(ref->dev, ref->dev_addr)) {
1072                         err_printk(ref->dev, NULL,
1073                                    "DMA-API: device driver tries to free an "
1074                                    "invalid DMA memory address\n");
1075                 } else {
1076                         err_printk(ref->dev, NULL,
1077                                    "DMA-API: device driver tries to free DMA "
1078                                    "memory it has not allocated [device "
1079                                    "address=0x%016llx] [size=%llu bytes]\n",
1080                                    ref->dev_addr, ref->size);
1081                 }
1082                 return;
1083         }
1084
1085         if (ref->size != entry->size) {
1086                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
1087                            "DMA memory with different size "
1088                            "[device address=0x%016llx] [map size=%llu bytes] "
1089                            "[unmap size=%llu bytes]\n",
1090                            ref->dev_addr, entry->size, ref->size);
1091         }
1092
1093         if (ref->type != entry->type) {
1094                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
1095                            "DMA memory with wrong function "
1096                            "[device address=0x%016llx] [size=%llu bytes] "
1097                            "[mapped as %s] [unmapped as %s]\n",
1098                            ref->dev_addr, ref->size,
1099                            type2name[entry->type], type2name[ref->type]);
1100         } else if ((entry->type == dma_debug_coherent) &&
1101                    (phys_addr(ref) != phys_addr(entry))) {
1102                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
1103                            "DMA memory with different CPU address "
1104                            "[device address=0x%016llx] [size=%llu bytes] "
1105                            "[cpu alloc address=0x%016llx] "
1106                            "[cpu free address=0x%016llx]",
1107                            ref->dev_addr, ref->size,
1108                            phys_addr(entry),
1109                            phys_addr(ref));
1110         }
1111
1112         if (ref->sg_call_ents && ref->type == dma_debug_sg &&
1113             ref->sg_call_ents != entry->sg_call_ents) {
1114                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
1115                            "DMA sg list with different entry count "
1116                            "[map count=%d] [unmap count=%d]\n",
1117                            entry->sg_call_ents, ref->sg_call_ents);
1118         }
1119
1120         /*
1121          * This may be no bug in reality - but most implementations of the
1122          * DMA API don't handle this properly, so check for it here
1123          */
1124         if (ref->direction != entry->direction) {
1125                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
1126                            "DMA memory with different direction "
1127                            "[device address=0x%016llx] [size=%llu bytes] "
1128                            "[mapped with %s] [unmapped with %s]\n",
1129                            ref->dev_addr, ref->size,
1130                            dir2name[entry->direction],
1131                            dir2name[ref->direction]);
1132         }
1133
1134         if (entry->map_err_type == MAP_ERR_NOT_CHECKED) {
1135                 err_printk(ref->dev, entry,
1136                            "DMA-API: device driver failed to check map error"
1137                            "[device address=0x%016llx] [size=%llu bytes] "
1138                            "[mapped as %s]",
1139                            ref->dev_addr, ref->size,
1140                            type2name[entry->type]);
1141         }
1142
1143         hash_bucket_del(entry);
1144         dma_entry_free(entry);
1145
1146         put_hash_bucket(bucket, &flags);
1147 }
1148
1149 static void check_for_stack(struct device *dev, void *addr)
1150 {
1151         if (object_is_on_stack(addr))
1152                 err_printk(dev, NULL, "DMA-API: device driver maps memory from"
1153                                 "stack [addr=%p]\n", addr);
1154 }
1155
1156 static inline bool overlap(void *addr, unsigned long len, void *start, void *end)
1157 {
1158         unsigned long a1 = (unsigned long)addr;
1159         unsigned long b1 = a1 + len;
1160         unsigned long a2 = (unsigned long)start;
1161         unsigned long b2 = (unsigned long)end;
1162
1163         return !(b1 <= a2 || a1 >= b2);
1164 }
1165
1166 static void check_for_illegal_area(struct device *dev, void *addr, unsigned long len)
1167 {
1168         if (overlap(addr, len, _text, _etext) ||
1169             overlap(addr, len, __start_rodata, __end_rodata))
1170                 err_printk(dev, NULL, "DMA-API: device driver maps memory from kernel text or rodata [addr=%p] [len=%lu]\n", addr, len);
1171 }
1172
1173 static void check_sync(struct device *dev,
1174                        struct dma_debug_entry *ref,
1175                        bool to_cpu)
1176 {
1177         struct dma_debug_entry *entry;
1178         struct hash_bucket *bucket;
1179         unsigned long flags;
1180
1181         bucket = get_hash_bucket(ref, &flags);
1182
1183         entry = bucket_find_contain(&bucket, ref, &flags);
1184
1185         if (!entry) {
1186                 err_printk(dev, NULL, "DMA-API: device driver tries "
1187                                 "to sync DMA memory it has not allocated "
1188                                 "[device address=0x%016llx] [size=%llu bytes]\n",
1189                                 (unsigned long long)ref->dev_addr, ref->size);
1190                 goto out;
1191         }
1192
1193         if (ref->size > entry->size) {
1194                 err_printk(dev, entry, "DMA-API: device driver syncs"
1195                                 " DMA memory outside allocated range "
1196                                 "[device address=0x%016llx] "
1197                                 "[allocation size=%llu bytes] "
1198                                 "[sync offset+size=%llu]\n",
1199                                 entry->dev_addr, entry->size,
1200                                 ref->size);
1201         }
1202
1203         if (entry->direction == DMA_BIDIRECTIONAL)
1204                 goto out;
1205
1206         if (ref->direction != entry->direction) {
1207                 err_printk(dev, entry, "DMA-API: device driver syncs "
1208                                 "DMA memory with different direction "
1209                                 "[device address=0x%016llx] [size=%llu bytes] "
1210                                 "[mapped with %s] [synced with %s]\n",
1211                                 (unsigned long long)ref->dev_addr, entry->size,
1212                                 dir2name[entry->direction],
1213                                 dir2name[ref->direction]);
1214         }
1215
1216         if (to_cpu && !(entry->direction == DMA_FROM_DEVICE) &&
1217                       !(ref->direction == DMA_TO_DEVICE))
1218                 err_printk(dev, entry, "DMA-API: device driver syncs "
1219                                 "device read-only DMA memory for cpu "
1220                                 "[device address=0x%016llx] [size=%llu bytes] "
1221                                 "[mapped with %s] [synced with %s]\n",
1222                                 (unsigned long long)ref->dev_addr, entry->size,
1223                                 dir2name[entry->direction],
1224                                 dir2name[ref->direction]);
1225
1226         if (!to_cpu && !(entry->direction == DMA_TO_DEVICE) &&
1227                        !(ref->direction == DMA_FROM_DEVICE))
1228                 err_printk(dev, entry, "DMA-API: device driver syncs "
1229                                 "device write-only DMA memory to device "
1230                                 "[device address=0x%016llx] [size=%llu bytes] "
1231                                 "[mapped with %s] [synced with %s]\n",
1232                                 (unsigned long long)ref->dev_addr, entry->size,
1233                                 dir2name[entry->direction],
1234                                 dir2name[ref->direction]);
1235
1236 out:
1237         put_hash_bucket(bucket, &flags);
1238 }
1239
1240 void debug_dma_map_page(struct device *dev, struct page *page, size_t offset,
1241                         size_t size, int direction, dma_addr_t dma_addr,
1242                         bool map_single)
1243 {
1244         struct dma_debug_entry *entry;
1245
1246         if (unlikely(global_disable))
1247                 return;
1248
1249         if (dma_mapping_error(dev, dma_addr))
1250                 return;
1251
1252         entry = dma_entry_alloc();
1253         if (!entry)
1254                 return;
1255
1256         entry->dev       = dev;
1257         entry->type      = dma_debug_page;
1258         entry->pfn       = page_to_pfn(page);
1259         entry->offset    = offset,
1260         entry->dev_addr  = dma_addr;
1261         entry->size      = size;
1262         entry->direction = direction;
1263         entry->map_err_type = MAP_ERR_NOT_CHECKED;
1264
1265         if (map_single)
1266                 entry->type = dma_debug_single;
1267
1268         if (!PageHighMem(page)) {
1269                 void *addr = page_address(page) + offset;
1270
1271                 check_for_stack(dev, addr);
1272                 check_for_illegal_area(dev, addr, size);
1273         }
1274
1275         add_dma_entry(entry);
1276 }
1277 EXPORT_SYMBOL(debug_dma_map_page);
1278
1279 void debug_dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
1280 {
1281         struct dma_debug_entry ref;
1282         struct dma_debug_entry *entry;
1283         struct hash_bucket *bucket;
1284         unsigned long flags;
1285
1286         if (unlikely(global_disable))
1287                 return;
1288
1289         ref.dev = dev;
1290         ref.dev_addr = dma_addr;
1291         bucket = get_hash_bucket(&ref, &flags);
1292
1293         list_for_each_entry(entry, &bucket->list, list) {
1294                 if (!exact_match(&ref, entry))
1295                         continue;
1296
1297                 /*
1298                  * The same physical address can be mapped multiple
1299                  * times. Without a hardware IOMMU this results in the
1300                  * same device addresses being put into the dma-debug
1301                  * hash multiple times too. This can result in false
1302                  * positives being reported. Therefore we implement a
1303                  * best-fit algorithm here which updates the first entry
1304                  * from the hash which fits the reference value and is
1305                  * not currently listed as being checked.
1306                  */
1307                 if (entry->map_err_type == MAP_ERR_NOT_CHECKED) {
1308                         entry->map_err_type = MAP_ERR_CHECKED;
1309                         break;
1310                 }
1311         }
1312
1313         put_hash_bucket(bucket, &flags);
1314 }
1315 EXPORT_SYMBOL(debug_dma_mapping_error);
1316
1317 void debug_dma_unmap_page(struct device *dev, dma_addr_t addr,
1318                           size_t size, int direction, bool map_single)
1319 {
1320         struct dma_debug_entry ref = {
1321                 .type           = dma_debug_page,
1322                 .dev            = dev,
1323                 .dev_addr       = addr,
1324                 .size           = size,
1325                 .direction      = direction,
1326         };
1327
1328         if (unlikely(global_disable))
1329                 return;
1330
1331         if (map_single)
1332                 ref.type = dma_debug_single;
1333
1334         check_unmap(&ref);
1335 }
1336 EXPORT_SYMBOL(debug_dma_unmap_page);
1337
1338 void debug_dma_map_sg(struct device *dev, struct scatterlist *sg,
1339                       int nents, int mapped_ents, int direction)
1340 {
1341         struct dma_debug_entry *entry;
1342         struct scatterlist *s;
1343         int i;
1344
1345         if (unlikely(global_disable))
1346                 return;
1347
1348         for_each_sg(sg, s, mapped_ents, i) {
1349                 entry = dma_entry_alloc();
1350                 if (!entry)
1351                         return;
1352
1353                 entry->type           = dma_debug_sg;
1354                 entry->dev            = dev;
1355                 entry->pfn            = page_to_pfn(sg_page(s));
1356                 entry->offset         = s->offset,
1357                 entry->size           = sg_dma_len(s);
1358                 entry->dev_addr       = sg_dma_address(s);
1359                 entry->direction      = direction;
1360                 entry->sg_call_ents   = nents;
1361                 entry->sg_mapped_ents = mapped_ents;
1362
1363                 if (!PageHighMem(sg_page(s))) {
1364                         check_for_stack(dev, sg_virt(s));
1365                         check_for_illegal_area(dev, sg_virt(s), sg_dma_len(s));
1366                 }
1367
1368                 add_dma_entry(entry);
1369         }
1370 }
1371 EXPORT_SYMBOL(debug_dma_map_sg);
1372
1373 static int get_nr_mapped_entries(struct device *dev,
1374                                  struct dma_debug_entry *ref)
1375 {
1376         struct dma_debug_entry *entry;
1377         struct hash_bucket *bucket;
1378         unsigned long flags;
1379         int mapped_ents;
1380
1381         bucket       = get_hash_bucket(ref, &flags);
1382         entry        = bucket_find_exact(bucket, ref);
1383         mapped_ents  = 0;
1384
1385         if (entry)
1386                 mapped_ents = entry->sg_mapped_ents;
1387         put_hash_bucket(bucket, &flags);
1388
1389         return mapped_ents;
1390 }
1391
1392 void debug_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
1393                         int nelems, int dir)
1394 {
1395         struct scatterlist *s;
1396         int mapped_ents = 0, i;
1397
1398         if (unlikely(global_disable))
1399                 return;
1400
1401         for_each_sg(sglist, s, nelems, i) {
1402
1403                 struct dma_debug_entry ref = {
1404                         .type           = dma_debug_sg,
1405                         .dev            = dev,
1406                         .pfn            = page_to_pfn(sg_page(s)),
1407                         .offset         = s->offset,
1408                         .dev_addr       = sg_dma_address(s),
1409                         .size           = sg_dma_len(s),
1410                         .direction      = dir,
1411                         .sg_call_ents   = nelems,
1412                 };
1413
1414                 if (mapped_ents && i >= mapped_ents)
1415                         break;
1416
1417                 if (!i)
1418                         mapped_ents = get_nr_mapped_entries(dev, &ref);
1419
1420                 check_unmap(&ref);
1421         }
1422 }
1423 EXPORT_SYMBOL(debug_dma_unmap_sg);
1424
1425 void debug_dma_alloc_coherent(struct device *dev, size_t size,
1426                               dma_addr_t dma_addr, void *virt)
1427 {
1428         struct dma_debug_entry *entry;
1429
1430         if (unlikely(global_disable))
1431                 return;
1432
1433         if (unlikely(virt == NULL))
1434                 return;
1435
1436         entry = dma_entry_alloc();
1437         if (!entry)
1438                 return;
1439
1440         entry->type      = dma_debug_coherent;
1441         entry->dev       = dev;
1442         entry->pfn       = page_to_pfn(virt_to_page(virt));
1443         entry->offset    = (size_t) virt & PAGE_MASK;
1444         entry->size      = size;
1445         entry->dev_addr  = dma_addr;
1446         entry->direction = DMA_BIDIRECTIONAL;
1447
1448         add_dma_entry(entry);
1449 }
1450 EXPORT_SYMBOL(debug_dma_alloc_coherent);
1451
1452 void debug_dma_free_coherent(struct device *dev, size_t size,
1453                          void *virt, dma_addr_t addr)
1454 {
1455         struct dma_debug_entry ref = {
1456                 .type           = dma_debug_coherent,
1457                 .dev            = dev,
1458                 .pfn            = page_to_pfn(virt_to_page(virt)),
1459                 .offset         = (size_t) virt & PAGE_MASK,
1460                 .dev_addr       = addr,
1461                 .size           = size,
1462                 .direction      = DMA_BIDIRECTIONAL,
1463         };
1464
1465         if (unlikely(global_disable))
1466                 return;
1467
1468         check_unmap(&ref);
1469 }
1470 EXPORT_SYMBOL(debug_dma_free_coherent);
1471
1472 void debug_dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_handle,
1473                                    size_t size, int direction)
1474 {
1475         struct dma_debug_entry ref;
1476
1477         if (unlikely(global_disable))
1478                 return;
1479
1480         ref.type         = dma_debug_single;
1481         ref.dev          = dev;
1482         ref.dev_addr     = dma_handle;
1483         ref.size         = size;
1484         ref.direction    = direction;
1485         ref.sg_call_ents = 0;
1486
1487         check_sync(dev, &ref, true);
1488 }
1489 EXPORT_SYMBOL(debug_dma_sync_single_for_cpu);
1490
1491 void debug_dma_sync_single_for_device(struct device *dev,
1492                                       dma_addr_t dma_handle, size_t size,
1493                                       int direction)
1494 {
1495         struct dma_debug_entry ref;
1496
1497         if (unlikely(global_disable))
1498                 return;
1499
1500         ref.type         = dma_debug_single;
1501         ref.dev          = dev;
1502         ref.dev_addr     = dma_handle;
1503         ref.size         = size;
1504         ref.direction    = direction;
1505         ref.sg_call_ents = 0;
1506
1507         check_sync(dev, &ref, false);
1508 }
1509 EXPORT_SYMBOL(debug_dma_sync_single_for_device);
1510
1511 void debug_dma_sync_single_range_for_cpu(struct device *dev,
1512                                          dma_addr_t dma_handle,
1513                                          unsigned long offset, size_t size,
1514                                          int direction)
1515 {
1516         struct dma_debug_entry ref;
1517
1518         if (unlikely(global_disable))
1519                 return;
1520
1521         ref.type         = dma_debug_single;
1522         ref.dev          = dev;
1523         ref.dev_addr     = dma_handle;
1524         ref.size         = offset + size;
1525         ref.direction    = direction;
1526         ref.sg_call_ents = 0;
1527
1528         check_sync(dev, &ref, true);
1529 }
1530 EXPORT_SYMBOL(debug_dma_sync_single_range_for_cpu);
1531
1532 void debug_dma_sync_single_range_for_device(struct device *dev,
1533                                             dma_addr_t dma_handle,
1534                                             unsigned long offset,
1535                                             size_t size, int direction)
1536 {
1537         struct dma_debug_entry ref;
1538
1539         if (unlikely(global_disable))
1540                 return;
1541
1542         ref.type         = dma_debug_single;
1543         ref.dev          = dev;
1544         ref.dev_addr     = dma_handle;
1545         ref.size         = offset + size;
1546         ref.direction    = direction;
1547         ref.sg_call_ents = 0;
1548
1549         check_sync(dev, &ref, false);
1550 }
1551 EXPORT_SYMBOL(debug_dma_sync_single_range_for_device);
1552
1553 void debug_dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
1554                                int nelems, int direction)
1555 {
1556         struct scatterlist *s;
1557         int mapped_ents = 0, i;
1558
1559         if (unlikely(global_disable))
1560                 return;
1561
1562         for_each_sg(sg, s, nelems, i) {
1563
1564                 struct dma_debug_entry ref = {
1565                         .type           = dma_debug_sg,
1566                         .dev            = dev,
1567                         .pfn            = page_to_pfn(sg_page(s)),
1568                         .offset         = s->offset,
1569                         .dev_addr       = sg_dma_address(s),
1570                         .size           = sg_dma_len(s),
1571                         .direction      = direction,
1572                         .sg_call_ents   = nelems,
1573                 };
1574
1575                 if (!i)
1576                         mapped_ents = get_nr_mapped_entries(dev, &ref);
1577
1578                 if (i >= mapped_ents)
1579                         break;
1580
1581                 check_sync(dev, &ref, true);
1582         }
1583 }
1584 EXPORT_SYMBOL(debug_dma_sync_sg_for_cpu);
1585
1586 void debug_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
1587                                   int nelems, int direction)
1588 {
1589         struct scatterlist *s;
1590         int mapped_ents = 0, i;
1591
1592         if (unlikely(global_disable))
1593                 return;
1594
1595         for_each_sg(sg, s, nelems, i) {
1596
1597                 struct dma_debug_entry ref = {
1598                         .type           = dma_debug_sg,
1599                         .dev            = dev,
1600                         .pfn            = page_to_pfn(sg_page(s)),
1601                         .offset         = s->offset,
1602                         .dev_addr       = sg_dma_address(s),
1603                         .size           = sg_dma_len(s),
1604                         .direction      = direction,
1605                         .sg_call_ents   = nelems,
1606                 };
1607                 if (!i)
1608                         mapped_ents = get_nr_mapped_entries(dev, &ref);
1609
1610                 if (i >= mapped_ents)
1611                         break;
1612
1613                 check_sync(dev, &ref, false);
1614         }
1615 }
1616 EXPORT_SYMBOL(debug_dma_sync_sg_for_device);
1617
1618 static int __init dma_debug_driver_setup(char *str)
1619 {
1620         int i;
1621
1622         for (i = 0; i < NAME_MAX_LEN - 1; ++i, ++str) {
1623                 current_driver_name[i] = *str;
1624                 if (*str == 0)
1625                         break;
1626         }
1627
1628         if (current_driver_name[0])
1629                 pr_info("DMA-API: enable driver filter for driver [%s]\n",
1630                         current_driver_name);
1631
1632
1633         return 1;
1634 }
1635 __setup("dma_debug_driver=", dma_debug_driver_setup);