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 page mapped (initial page in the case of
 428  * dma_alloc_coherent/dma_map_{single|page}, or each page in a
 429  * scatterlist) insert into this tree using the pfn as the key. At
 430  * dma_unmap_{single|sg|page} or dma_free_coherent delete the entry.  If
 431  * the pfn already exists at insertion time add a tag as a reference
 432  * count for the overlapping mappings.  For now, the overlap tracking
 433  * just ensures that 'unmaps' balance 'maps' before marking the pfn
 434  * idle, but we should also be flagging overlaps as an API violation.
 435  *
 436  * Memory usage is mostly constrained by the maximum number of available
 437  * dma-debug entries in that we need a free dma_debug_entry before
 438  * inserting into the tree.  In the case of dma_map_{single|page} and
 439  * dma_alloc_coherent there is only one dma_debug_entry and one pfn to
 440  * track per event.  dma_map_sg(), on the other hand,
 441  * consumes a single dma_debug_entry, but inserts 'nents' entries into
 442  * the tree.
 443  *
 444  * At any time debug_dma_assert_idle() can be called to trigger a
 445  * warning if the given page is in the active set.
 446  */
 447 static RADIX_TREE(dma_active_pfn, GFP_NOWAIT);
 448 static DEFINE_SPINLOCK(radix_lock);
 449 #define ACTIVE_PFN_MAX_OVERLAP ((1 << RADIX_TREE_MAX_TAGS) - 1)
 450
 451 static int active_pfn_read_overlap(unsigned long pfn)
 452 {
 453         int overlap = 0, i;
 454
 455         for (i = RADIX_TREE_MAX_TAGS - 1; i >= 0; i--)
 456                 if (radix_tree_tag_get(&dma_active_pfn, pfn, i))
 457                         overlap |= 1 << i;
 458         return overlap;
 459 }
 460
 461 static int active_pfn_set_overlap(unsigned long pfn, int overlap)
 462 {
 463         int i;
 464
 465         if (overlap > ACTIVE_PFN_MAX_OVERLAP || overlap < 0)
 466                 return 0;
 467
 468         for (i = RADIX_TREE_MAX_TAGS - 1; i >= 0; i--)
 469                 if (overlap & 1 << i)
 470                         radix_tree_tag_set(&dma_active_pfn, pfn, i);
 471                 else
 472                         radix_tree_tag_clear(&dma_active_pfn, pfn, i);
 473
 474         return overlap;
 475 }
 476
 477 static void active_pfn_inc_overlap(unsigned long pfn)
 478 {
 479         int overlap = active_pfn_read_overlap(pfn);
 480
 481         overlap = active_pfn_set_overlap(pfn, ++overlap);
 482
 483         /* If we overflowed the overlap counter then we're potentially
 484          * leaking dma-mappings.  Otherwise, if maps and unmaps are
 485          * balanced then this overflow may cause false negatives in
 486          * debug_dma_assert_idle() as the pfn may be marked idle
 487          * prematurely.
 488          */
 489         WARN_ONCE(overlap == 0,
 490                   "DMA-API: exceeded %d overlapping mappings of pfn %lx\n",
 491                   ACTIVE_PFN_MAX_OVERLAP, pfn);
 492 }
 493
 494 static int active_pfn_dec_overlap(unsigned long pfn)
 495 {
 496         int overlap = active_pfn_read_overlap(pfn);
 497
 498         return active_pfn_set_overlap(pfn, --overlap);
 499 }
 500
 501 static int active_pfn_insert(struct dma_debug_entry *entry)
 502 {
 503         unsigned long flags;
 504         int rc;
 505
 506         spin_lock_irqsave(&radix_lock, flags);
 507         rc = radix_tree_insert(&dma_active_pfn, entry->pfn, entry);
 508         if (rc == -EEXIST)
 509                 active_pfn_inc_overlap(entry->pfn);
 510         spin_unlock_irqrestore(&radix_lock, flags);
 511
 512         return rc;
 513 }
 514
 515 static void active_pfn_remove(struct dma_debug_entry *entry)
 516 {
 517         unsigned long flags;
 518
 519         spin_lock_irqsave(&radix_lock, flags);
 520         if (active_pfn_dec_overlap(entry->pfn) == 0)
 521                 radix_tree_delete(&dma_active_pfn, entry->pfn);
 522         spin_unlock_irqrestore(&radix_lock, flags);
 523 }
 524
 525 /**
 526  * debug_dma_assert_idle() - assert that a page is not undergoing dma
 527  * @page: page to lookup in the dma_active_pfn tree
 528  *
 529  * Place a call to this routine in cases where the cpu touching the page
 530  * before the dma completes (page is dma_unmapped) will lead to data
 531  * corruption.
 532  */
 533 void debug_dma_assert_idle(struct page *page)
 534 {
 535         unsigned long flags;
 536         struct dma_debug_entry *entry;
 537
 538         if (!page)
 539                 return;
 540
 541         spin_lock_irqsave(&radix_lock, flags);
 542         entry = radix_tree_lookup(&dma_active_pfn, page_to_pfn(page));
 543         spin_unlock_irqrestore(&radix_lock, flags);
 544
 545         if (!entry)
 546                 return;
 547
 548         err_printk(entry->dev, entry,
 549                    "DMA-API: cpu touching an active dma mapped page "
 550                    "[pfn=0x%lx]\n", entry->pfn);
 551 }
 552
 553 /*
 554  * Wrapper function for adding an entry to the hash.
 555  * This function takes care of locking itself.
 556  */
 557 static void add_dma_entry(struct dma_debug_entry *entry)
 558 {
 559         struct hash_bucket *bucket;
 560         unsigned long flags;
 561         int rc;
 562
 563         bucket = get_hash_bucket(entry, &flags);
 564         hash_bucket_add(bucket, entry);
 565         put_hash_bucket(bucket, &flags);
 566
 567         rc = active_pfn_insert(entry);
 568         if (rc == -ENOMEM) {
 569                 pr_err("DMA-API: pfn tracking ENOMEM, dma-debug disabled\n");
 570                 global_disable = true;
 571         }
 572
 573         /* TODO: report -EEXIST errors here as overlapping mappings are
 574          * not supported by the DMA API
 575          */
 576 }
 577
 578 static struct dma_debug_entry *__dma_entry_alloc(void)
 579 {
 580         struct dma_debug_entry *entry;
 581
 582         entry = list_entry(free_entries.next, struct dma_debug_entry, list);
 583         list_del(&entry->list);
 584         memset(entry, 0, sizeof(*entry));
 585
 586         num_free_entries -= 1;
 587         if (num_free_entries < min_free_entries)
 588                 min_free_entries = num_free_entries;
 589
 590         return entry;
 591 }
 592
 593 /* struct dma_entry allocator
 594  *
 595  * The next two functions implement the allocator for
 596  * struct dma_debug_entries.
 597  */
 598 static struct dma_debug_entry *dma_entry_alloc(void)
 599 {
 600         struct dma_debug_entry *entry;
 601         unsigned long flags;
 602
 603         spin_lock_irqsave(&free_entries_lock, flags);
 604
 605         if (list_empty(&free_entries)) {
 606                 pr_err("DMA-API: debugging out of memory - disabling\n");
 607                 global_disable = true;
 608                 spin_unlock_irqrestore(&free_entries_lock, flags);
 609                 return NULL;
 610         }
 611
 612         entry = __dma_entry_alloc();
 613
 614         spin_unlock_irqrestore(&free_entries_lock, flags);
 615
 616 #ifdef CONFIG_STACKTRACE
 617         entry->stacktrace.max_entries = DMA_DEBUG_STACKTRACE_ENTRIES;
 618         entry->stacktrace.entries = entry->st_entries;
 619         entry->stacktrace.skip = 2;
 620         save_stack_trace(&entry->stacktrace);
 621 #endif
 622
 623         return entry;
 624 }
 625
 626 static void dma_entry_free(struct dma_debug_entry *entry)
 627 {
 628         unsigned long flags;
 629
 630         active_pfn_remove(entry);
 631
 632         /*
 633          * add to beginning of the list - this way the entries are
 634          * more likely cache hot when they are reallocated.
 635          */
 636         spin_lock_irqsave(&free_entries_lock, flags);
 637         list_add(&entry->list, &free_entries);
 638         num_free_entries += 1;
 639         spin_unlock_irqrestore(&free_entries_lock, flags);
 640 }
 641
 642 int dma_debug_resize_entries(u32 num_entries)
 643 {
 644         int i, delta, ret = 0;
 645         unsigned long flags;
 646         struct dma_debug_entry *entry;
 647         LIST_HEAD(tmp);
 648
 649         spin_lock_irqsave(&free_entries_lock, flags);
 650
 651         if (nr_total_entries < num_entries) {
 652                 delta = num_entries - nr_total_entries;
 653
 654                 spin_unlock_irqrestore(&free_entries_lock, flags);
 655
 656                 for (i = 0; i < delta; i++) {
 657                         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 658                         if (!entry)
 659                                 break;
 660
 661                         list_add_tail(&entry->list, &tmp);
 662                 }
 663
 664                 spin_lock_irqsave(&free_entries_lock, flags);
 665
 666                 list_splice(&tmp, &free_entries);
 667                 nr_total_entries += i;
 668                 num_free_entries += i;
 669         } else {
 670                 delta = nr_total_entries - num_entries;
 671
 672                 for (i = 0; i < delta && !list_empty(&free_entries); i++) {
 673                         entry = __dma_entry_alloc();
 674                         kfree(entry);
 675                 }
 676
 677                 nr_total_entries -= i;
 678         }
 679
 680         if (nr_total_entries != num_entries)
 681                 ret = 1;
 682
 683         spin_unlock_irqrestore(&free_entries_lock, flags);
 684
 685         return ret;
 686 }
 687 EXPORT_SYMBOL(dma_debug_resize_entries);
 688
 689 /*
 690  * DMA-API debugging init code
 691  *
 692  * The init code does two things:
 693  *   1. Initialize core data structures
 694  *   2. Preallocate a given number of dma_debug_entry structs
 695  */
 696
 697 static int prealloc_memory(u32 num_entries)
 698 {
 699         struct dma_debug_entry *entry, *next_entry;
 700         int i;
 701
 702         for (i = 0; i < num_entries; ++i) {
 703                 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 704                 if (!entry)
 705                         goto out_err;
 706
 707                 list_add_tail(&entry->list, &free_entries);
 708         }
 709
 710         num_free_entries = num_entries;
 711         min_free_entries = num_entries;
 712
 713         pr_info("DMA-API: preallocated %d debug entries\n", num_entries);
 714
 715         return 0;
 716
 717 out_err:
 718
 719         list_for_each_entry_safe(entry, next_entry, &free_entries, list) {
 720                 list_del(&entry->list);
 721                 kfree(entry);
 722         }
 723
 724         return -ENOMEM;
 725 }
 726
 727 static ssize_t filter_read(struct file *file, char __user *user_buf,
 728                            size_t count, loff_t *ppos)
 729 {
 730         char buf[NAME_MAX_LEN + 1];
 731         unsigned long flags;
 732         int len;
 733
 734         if (!current_driver_name[0])
 735                 return 0;
 736
 737         /*
 738          * We can't copy to userspace directly because current_driver_name can
 739          * only be read under the driver_name_lock with irqs disabled. So
 740          * create a temporary copy first.
 741          */
 742         read_lock_irqsave(&driver_name_lock, flags);
 743         len = scnprintf(buf, NAME_MAX_LEN + 1, "%s\n", current_driver_name);
 744         read_unlock_irqrestore(&driver_name_lock, flags);
 745
 746         return simple_read_from_buffer(user_buf, count, ppos, buf, len);
 747 }
 748
 749 static ssize_t filter_write(struct file *file, const char __user *userbuf,
 750                             size_t count, loff_t *ppos)
 751 {
 752         char buf[NAME_MAX_LEN];
 753         unsigned long flags;
 754         size_t len;
 755         int i;
 756
 757         /*
 758          * We can't copy from userspace directly. Access to
 759          * current_driver_name is protected with a write_lock with irqs
 760          * disabled. Since copy_from_user can fault and may sleep we
 761          * need to copy to temporary buffer first
 762          */
 763         len = min(count, (size_t)(NAME_MAX_LEN - 1));
 764         if (copy_from_user(buf, userbuf, len))
 765                 return -EFAULT;
 766
 767         buf[len] = 0;
 768
 769         write_lock_irqsave(&driver_name_lock, flags);
 770
 771         /*
 772          * Now handle the string we got from userspace very carefully.
 773          * The rules are:
 774          *         - only use the first token we got
 775          *         - token delimiter is everything looking like a space
 776          *           character (' ', '\n', '\t' ...)
 777          *
 778          */
 779         if (!isalnum(buf[0])) {
 780                 /*
 781                  * If the first character userspace gave us is not
 782                  * alphanumerical then assume the filter should be
 783                  * switched off.
 784                  */
 785                 if (current_driver_name[0])
 786                         pr_info("DMA-API: switching off dma-debug driver filter\n");
 787                 current_driver_name[0] = 0;
 788                 current_driver = NULL;
 789                 goto out_unlock;
 790         }
 791
 792         /*
 793          * Now parse out the first token and use it as the name for the
 794          * driver to filter for.
 795          */
 796         for (i = 0; i < NAME_MAX_LEN - 1; ++i) {
 797                 current_driver_name[i] = buf[i];
 798                 if (isspace(buf[i]) || buf[i] == ' ' || buf[i] == 0)
 799                         break;
 800         }
 801         current_driver_name[i] = 0;
 802         current_driver = NULL;
 803
 804         pr_info("DMA-API: enable driver filter for driver [%s]\n",
 805                 current_driver_name);
 806
 807 out_unlock:
 808         write_unlock_irqrestore(&driver_name_lock, flags);
 809
 810         return count;
 811 }
 812
 813 static const struct file_operations filter_fops = {
 814         .read  = filter_read,
 815         .write = filter_write,
 816         .llseek = default_llseek,
 817 };
 818
 819 static int dma_debug_fs_init(void)
 820 {
 821         dma_debug_dent = debugfs_create_dir("dma-api", NULL);
 822         if (!dma_debug_dent) {
 823                 pr_err("DMA-API: can not create debugfs directory\n");
 824                 return -ENOMEM;
 825         }
 826
 827         global_disable_dent = debugfs_create_bool("disabled", 0444,
 828                         dma_debug_dent,
 829                         &global_disable);
 830         if (!global_disable_dent)
 831                 goto out_err;
 832
 833         error_count_dent = debugfs_create_u32("error_count", 0444,
 834                         dma_debug_dent, &error_count);
 835         if (!error_count_dent)
 836                 goto out_err;
 837
 838         show_all_errors_dent = debugfs_create_u32("all_errors", 0644,
 839                         dma_debug_dent,
 840                         &show_all_errors);
 841         if (!show_all_errors_dent)
 842                 goto out_err;
 843
 844         show_num_errors_dent = debugfs_create_u32("num_errors", 0644,
 845                         dma_debug_dent,
 846                         &show_num_errors);
 847         if (!show_num_errors_dent)
 848                 goto out_err;
 849
 850         num_free_entries_dent = debugfs_create_u32("num_free_entries", 0444,
 851                         dma_debug_dent,
 852                         &num_free_entries);
 853         if (!num_free_entries_dent)
 854                 goto out_err;
 855
 856         min_free_entries_dent = debugfs_create_u32("min_free_entries", 0444,
 857                         dma_debug_dent,
 858                         &min_free_entries);
 859         if (!min_free_entries_dent)
 860                 goto out_err;
 861
 862         filter_dent = debugfs_create_file("driver_filter", 0644,
 863                                           dma_debug_dent, NULL, &filter_fops);
 864         if (!filter_dent)
 865                 goto out_err;
 866
 867         return 0;
 868
 869 out_err:
 870         debugfs_remove_recursive(dma_debug_dent);
 871
 872         return -ENOMEM;
 873 }
 874
 875 static int device_dma_allocations(struct device *dev, struct dma_debug_entry **out_entry)
 876 {
 877         struct dma_debug_entry *entry;
 878         unsigned long flags;
 879         int count = 0, i;
 880
 881         local_irq_save(flags);
 882
 883         for (i = 0; i < HASH_SIZE; ++i) {
 884                 spin_lock(&dma_entry_hash[i].lock);
 885                 list_for_each_entry(entry, &dma_entry_hash[i].list, list) {
 886                         if (entry->dev == dev) {
 887                                 count += 1;
 888                                 *out_entry = entry;
 889                         }
 890                 }
 891                 spin_unlock(&dma_entry_hash[i].lock);
 892         }
 893
 894         local_irq_restore(flags);
 895
 896         return count;
 897 }
 898
 899 static int dma_debug_device_change(struct notifier_block *nb, unsigned long action, void *data)
 900 {
 901         struct device *dev = data;
 902         struct dma_debug_entry *uninitialized_var(entry);
 903         int count;
 904
 905         if (global_disable)
 906                 return 0;
 907
 908         switch (action) {
 909         case BUS_NOTIFY_UNBOUND_DRIVER:
 910                 count = device_dma_allocations(dev, &entry);
 911                 if (count == 0)
 912                         break;
 913                 err_printk(dev, entry, "DMA-API: device driver has pending "
 914                                 "DMA allocations while released from device "
 915                                 "[count=%d]\n"
 916                                 "One of leaked entries details: "
 917                                 "[device address=0x%016llx] [size=%llu bytes] "
 918                                 "[mapped with %s] [mapped as %s]\n",
 919                         count, entry->dev_addr, entry->size,
 920                         dir2name[entry->direction], type2name[entry->type]);
 921                 break;
 922         default:
 923                 break;
 924         }
 925
 926         return 0;
 927 }
 928
 929 void dma_debug_add_bus(struct bus_type *bus)
 930 {
 931         struct notifier_block *nb;
 932
 933         if (global_disable)
 934                 return;
 935
 936         nb = kzalloc(sizeof(struct notifier_block), GFP_KERNEL);
 937         if (nb == NULL) {
 938                 pr_err("dma_debug_add_bus: out of memory\n");
 939                 return;
 940         }
 941
 942         nb->notifier_call = dma_debug_device_change;
 943
 944         bus_register_notifier(bus, nb);
 945 }
 946
 947 /*
 948  * Let the architectures decide how many entries should be preallocated.
 949  */
 950 void dma_debug_init(u32 num_entries)
 951 {
 952         int i;
 953
 954         if (global_disable)
 955                 return;
 956
 957         for (i = 0; i < HASH_SIZE; ++i) {
 958                 INIT_LIST_HEAD(&dma_entry_hash[i].list);
 959                 spin_lock_init(&dma_entry_hash[i].lock);
 960         }
 961
 962         if (dma_debug_fs_init() != 0) {
 963                 pr_err("DMA-API: error creating debugfs entries - disabling\n");
 964                 global_disable = true;
 965
 966                 return;
 967         }
 968
 969         if (req_entries)
 970                 num_entries = req_entries;
 971
 972         if (prealloc_memory(num_entries) != 0) {
 973                 pr_err("DMA-API: debugging out of memory error - disabled\n");
 974                 global_disable = true;
 975
 976                 return;
 977         }
 978
 979         nr_total_entries = num_free_entries;
 980
 981         pr_info("DMA-API: debugging enabled by kernel config\n");
 982 }
 983
 984 static __init int dma_debug_cmdline(char *str)
 985 {
 986         if (!str)
 987                 return -EINVAL;
 988
 989         if (strncmp(str, "off", 3) == 0) {
 990                 pr_info("DMA-API: debugging disabled on kernel command line\n");
 991                 global_disable = true;
 992         }
 993
 994         return 0;
 995 }
 996
 997 static __init int dma_debug_entries_cmdline(char *str)
 998 {
 999         int res;
1000
1001         if (!str)
1002                 return -EINVAL;
1003
1004         res = get_option(&str, &req_entries);
1005
1006         if (!res)
1007                 req_entries = 0;
1008
1009         return 0;
1010 }
1011
1012 __setup("dma_debug=", dma_debug_cmdline);
1013 __setup("dma_debug_entries=", dma_debug_entries_cmdline);
1014
1015 static void check_unmap(struct dma_debug_entry *ref)
1016 {
1017         struct dma_debug_entry *entry;
1018         struct hash_bucket *bucket;
1019         unsigned long flags;
1020
1021         bucket = get_hash_bucket(ref, &flags);
1022         entry = bucket_find_exact(bucket, ref);
1023
1024         if (!entry) {
1025                 /* must drop lock before calling dma_mapping_error */
1026                 put_hash_bucket(bucket, &flags);
1027
1028                 if (dma_mapping_error(ref->dev, ref->dev_addr)) {
1029                         err_printk(ref->dev, NULL,
1030                                    "DMA-API: device driver tries to free an "
1031                                    "invalid DMA memory address\n");
1032                 } else {
1033                         err_printk(ref->dev, NULL,
1034                                    "DMA-API: device driver tries to free DMA "
1035                                    "memory it has not allocated [device "
1036                                    "address=0x%016llx] [size=%llu bytes]\n",
1037                                    ref->dev_addr, ref->size);
1038                 }
1039                 return;
1040         }
1041
1042         if (ref->size != entry->size) {
1043                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
1044                            "DMA memory with different size "
1045                            "[device address=0x%016llx] [map size=%llu bytes] "
1046                            "[unmap size=%llu bytes]\n",
1047                            ref->dev_addr, entry->size, ref->size);
1048         }
1049
1050         if (ref->type != entry->type) {
1051                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
1052                            "DMA memory with wrong function "
1053                            "[device address=0x%016llx] [size=%llu bytes] "
1054                            "[mapped as %s] [unmapped as %s]\n",
1055                            ref->dev_addr, ref->size,
1056                            type2name[entry->type], type2name[ref->type]);
1057         } else if ((entry->type == dma_debug_coherent) &&
1058                    (phys_addr(ref) != phys_addr(entry))) {
1059                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
1060                            "DMA memory with different CPU address "
1061                            "[device address=0x%016llx] [size=%llu bytes] "
1062                            "[cpu alloc address=0x%016llx] "
1063                            "[cpu free address=0x%016llx]",
1064                            ref->dev_addr, ref->size,
1065                            phys_addr(entry),
1066                            phys_addr(ref));
1067         }
1068
1069         if (ref->sg_call_ents && ref->type == dma_debug_sg &&
1070             ref->sg_call_ents != entry->sg_call_ents) {
1071                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
1072                            "DMA sg list with different entry count "
1073                            "[map count=%d] [unmap count=%d]\n",
1074                            entry->sg_call_ents, ref->sg_call_ents);
1075         }
1076
1077         /*
1078          * This may be no bug in reality - but most implementations of the
1079          * DMA API don't handle this properly, so check for it here
1080          */
1081         if (ref->direction != entry->direction) {
1082                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
1083                            "DMA memory with different direction "
1084                            "[device address=0x%016llx] [size=%llu bytes] "
1085                            "[mapped with %s] [unmapped with %s]\n",
1086                            ref->dev_addr, ref->size,
1087                            dir2name[entry->direction],
1088                            dir2name[ref->direction]);
1089         }
1090
1091         if (entry->map_err_type == MAP_ERR_NOT_CHECKED) {
1092                 err_printk(ref->dev, entry,
1093                            "DMA-API: device driver failed to check map error"
1094                            "[device address=0x%016llx] [size=%llu bytes] "
1095                            "[mapped as %s]",
1096                            ref->dev_addr, ref->size,
1097                            type2name[entry->type]);
1098         }
1099
1100         hash_bucket_del(entry);
1101         dma_entry_free(entry);
1102
1103         put_hash_bucket(bucket, &flags);
1104 }
1105
1106 static void check_for_stack(struct device *dev, void *addr)
1107 {
1108         if (object_is_on_stack(addr))
1109                 err_printk(dev, NULL, "DMA-API: device driver maps memory from"
1110                                 "stack [addr=%p]\n", addr);
1111 }
1112
1113 static inline bool overlap(void *addr, unsigned long len, void *start, void *end)
1114 {
1115         unsigned long a1 = (unsigned long)addr;
1116         unsigned long b1 = a1 + len;
1117         unsigned long a2 = (unsigned long)start;
1118         unsigned long b2 = (unsigned long)end;
1119
1120         return !(b1 <= a2 || a1 >= b2);
1121 }
1122
1123 static void check_for_illegal_area(struct device *dev, void *addr, unsigned long len)
1124 {
1125         if (overlap(addr, len, _text, _etext) ||
1126             overlap(addr, len, __start_rodata, __end_rodata))
1127                 err_printk(dev, NULL, "DMA-API: device driver maps memory from kernel text or rodata [addr=%p] [len=%lu]\n", addr, len);
1128 }
1129
1130 static void check_sync(struct device *dev,
1131                        struct dma_debug_entry *ref,
1132                        bool to_cpu)
1133 {
1134         struct dma_debug_entry *entry;
1135         struct hash_bucket *bucket;
1136         unsigned long flags;
1137
1138         bucket = get_hash_bucket(ref, &flags);
1139
1140         entry = bucket_find_contain(&bucket, ref, &flags);
1141
1142         if (!entry) {
1143                 err_printk(dev, NULL, "DMA-API: device driver tries "
1144                                 "to sync DMA memory it has not allocated "
1145                                 "[device address=0x%016llx] [size=%llu bytes]\n",
1146                                 (unsigned long long)ref->dev_addr, ref->size);
1147                 goto out;
1148         }
1149
1150         if (ref->size > entry->size) {
1151                 err_printk(dev, entry, "DMA-API: device driver syncs"
1152                                 " DMA memory outside allocated range "
1153                                 "[device address=0x%016llx] "
1154                                 "[allocation size=%llu bytes] "
1155                                 "[sync offset+size=%llu]\n",
1156                                 entry->dev_addr, entry->size,
1157                                 ref->size);
1158         }
1159
1160         if (entry->direction == DMA_BIDIRECTIONAL)
1161                 goto out;
1162
1163         if (ref->direction != entry->direction) {
1164                 err_printk(dev, entry, "DMA-API: device driver syncs "
1165                                 "DMA memory with different direction "
1166                                 "[device address=0x%016llx] [size=%llu bytes] "
1167                                 "[mapped with %s] [synced with %s]\n",
1168                                 (unsigned long long)ref->dev_addr, entry->size,
1169                                 dir2name[entry->direction],
1170                                 dir2name[ref->direction]);
1171         }
1172
1173         if (to_cpu && !(entry->direction == DMA_FROM_DEVICE) &&
1174                       !(ref->direction == DMA_TO_DEVICE))
1175                 err_printk(dev, entry, "DMA-API: device driver syncs "
1176                                 "device read-only DMA memory for cpu "
1177                                 "[device address=0x%016llx] [size=%llu bytes] "
1178                                 "[mapped with %s] [synced with %s]\n",
1179                                 (unsigned long long)ref->dev_addr, entry->size,
1180                                 dir2name[entry->direction],
1181                                 dir2name[ref->direction]);
1182
1183         if (!to_cpu && !(entry->direction == DMA_TO_DEVICE) &&
1184                        !(ref->direction == DMA_FROM_DEVICE))
1185                 err_printk(dev, entry, "DMA-API: device driver syncs "
1186                                 "device write-only DMA memory to device "
1187                                 "[device address=0x%016llx] [size=%llu bytes] "
1188                                 "[mapped with %s] [synced with %s]\n",
1189                                 (unsigned long long)ref->dev_addr, entry->size,
1190                                 dir2name[entry->direction],
1191                                 dir2name[ref->direction]);
1192
1193 out:
1194         put_hash_bucket(bucket, &flags);
1195 }
1196
1197 void debug_dma_map_page(struct device *dev, struct page *page, size_t offset,
1198                         size_t size, int direction, dma_addr_t dma_addr,
1199                         bool map_single)
1200 {
1201         struct dma_debug_entry *entry;
1202
1203         if (unlikely(global_disable))
1204                 return;
1205
1206         if (dma_mapping_error(dev, dma_addr))
1207                 return;
1208
1209         entry = dma_entry_alloc();
1210         if (!entry)
1211                 return;
1212
1213         entry->dev       = dev;
1214         entry->type      = dma_debug_page;
1215         entry->pfn       = page_to_pfn(page);
1216         entry->offset    = offset,
1217         entry->dev_addr  = dma_addr;
1218         entry->size      = size;
1219         entry->direction = direction;
1220         entry->map_err_type = MAP_ERR_NOT_CHECKED;
1221
1222         if (map_single)
1223                 entry->type = dma_debug_single;
1224
1225         if (!PageHighMem(page)) {
1226                 void *addr = page_address(page) + offset;
1227
1228                 check_for_stack(dev, addr);
1229                 check_for_illegal_area(dev, addr, size);
1230         }
1231
1232         add_dma_entry(entry);
1233 }
1234 EXPORT_SYMBOL(debug_dma_map_page);
1235
1236 void debug_dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
1237 {
1238         struct dma_debug_entry ref;
1239         struct dma_debug_entry *entry;
1240         struct hash_bucket *bucket;
1241         unsigned long flags;
1242
1243         if (unlikely(global_disable))
1244                 return;
1245
1246         ref.dev = dev;
1247         ref.dev_addr = dma_addr;
1248         bucket = get_hash_bucket(&ref, &flags);
1249
1250         list_for_each_entry(entry, &bucket->list, list) {
1251                 if (!exact_match(&ref, entry))
1252                         continue;
1253
1254                 /*
1255                  * The same physical address can be mapped multiple
1256                  * times. Without a hardware IOMMU this results in the
1257                  * same device addresses being put into the dma-debug
1258                  * hash multiple times too. This can result in false
1259                  * positives being reported. Therefore we implement a
1260                  * best-fit algorithm here which updates the first entry
1261                  * from the hash which fits the reference value and is
1262                  * not currently listed as being checked.
1263                  */
1264                 if (entry->map_err_type == MAP_ERR_NOT_CHECKED) {
1265                         entry->map_err_type = MAP_ERR_CHECKED;
1266                         break;
1267                 }
1268         }
1269
1270         put_hash_bucket(bucket, &flags);
1271 }
1272 EXPORT_SYMBOL(debug_dma_mapping_error);
1273
1274 void debug_dma_unmap_page(struct device *dev, dma_addr_t addr,
1275                           size_t size, int direction, bool map_single)
1276 {
1277         struct dma_debug_entry ref = {
1278                 .type           = dma_debug_page,
1279                 .dev            = dev,
1280                 .dev_addr       = addr,
1281                 .size           = size,
1282                 .direction      = direction,
1283         };
1284
1285         if (unlikely(global_disable))
1286                 return;
1287
1288         if (map_single)
1289                 ref.type = dma_debug_single;
1290
1291         check_unmap(&ref);
1292 }
1293 EXPORT_SYMBOL(debug_dma_unmap_page);
1294
1295 void debug_dma_map_sg(struct device *dev, struct scatterlist *sg,
1296                       int nents, int mapped_ents, int direction)
1297 {
1298         struct dma_debug_entry *entry;
1299         struct scatterlist *s;
1300         int i;
1301
1302         if (unlikely(global_disable))
1303                 return;
1304
1305         for_each_sg(sg, s, mapped_ents, i) {
1306                 entry = dma_entry_alloc();
1307                 if (!entry)
1308                         return;
1309
1310                 entry->type           = dma_debug_sg;
1311                 entry->dev            = dev;
1312                 entry->pfn            = page_to_pfn(sg_page(s));
1313                 entry->offset         = s->offset,
1314                 entry->size           = sg_dma_len(s);
1315                 entry->dev_addr       = sg_dma_address(s);
1316                 entry->direction      = direction;
1317                 entry->sg_call_ents   = nents;
1318                 entry->sg_mapped_ents = mapped_ents;
1319
1320                 if (!PageHighMem(sg_page(s))) {
1321                         check_for_stack(dev, sg_virt(s));
1322                         check_for_illegal_area(dev, sg_virt(s), sg_dma_len(s));
1323                 }
1324
1325                 add_dma_entry(entry);
1326         }
1327 }
1328 EXPORT_SYMBOL(debug_dma_map_sg);
1329
1330 static int get_nr_mapped_entries(struct device *dev,
1331                                  struct dma_debug_entry *ref)
1332 {
1333         struct dma_debug_entry *entry;
1334         struct hash_bucket *bucket;
1335         unsigned long flags;
1336         int mapped_ents;
1337
1338         bucket       = get_hash_bucket(ref, &flags);
1339         entry        = bucket_find_exact(bucket, ref);
1340         mapped_ents  = 0;
1341
1342         if (entry)
1343                 mapped_ents = entry->sg_mapped_ents;
1344         put_hash_bucket(bucket, &flags);
1345
1346         return mapped_ents;
1347 }
1348
1349 void debug_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
1350                         int nelems, int dir)
1351 {
1352         struct scatterlist *s;
1353         int mapped_ents = 0, i;
1354
1355         if (unlikely(global_disable))
1356                 return;
1357
1358         for_each_sg(sglist, s, nelems, i) {
1359
1360                 struct dma_debug_entry ref = {
1361                         .type           = dma_debug_sg,
1362                         .dev            = dev,
1363                         .pfn            = page_to_pfn(sg_page(s)),
1364                         .offset         = s->offset,
1365                         .dev_addr       = sg_dma_address(s),
1366                         .size           = sg_dma_len(s),
1367                         .direction      = dir,
1368                         .sg_call_ents   = nelems,
1369                 };
1370
1371                 if (mapped_ents && i >= mapped_ents)
1372                         break;
1373
1374                 if (!i)
1375                         mapped_ents = get_nr_mapped_entries(dev, &ref);
1376
1377                 check_unmap(&ref);
1378         }
1379 }
1380 EXPORT_SYMBOL(debug_dma_unmap_sg);
1381
1382 void debug_dma_alloc_coherent(struct device *dev, size_t size,
1383                               dma_addr_t dma_addr, void *virt)
1384 {
1385         struct dma_debug_entry *entry;
1386
1387         if (unlikely(global_disable))
1388                 return;
1389
1390         if (unlikely(virt == NULL))
1391                 return;
1392
1393         entry = dma_entry_alloc();
1394         if (!entry)
1395                 return;
1396
1397         entry->type      = dma_debug_coherent;
1398         entry->dev       = dev;
1399         entry->pfn       = page_to_pfn(virt_to_page(virt));
1400         entry->offset    = (size_t) virt & PAGE_MASK;
1401         entry->size      = size;
1402         entry->dev_addr  = dma_addr;
1403         entry->direction = DMA_BIDIRECTIONAL;
1404
1405         add_dma_entry(entry);
1406 }
1407 EXPORT_SYMBOL(debug_dma_alloc_coherent);
1408
1409 void debug_dma_free_coherent(struct device *dev, size_t size,
1410                          void *virt, dma_addr_t addr)
1411 {
1412         struct dma_debug_entry ref = {
1413                 .type           = dma_debug_coherent,
1414                 .dev            = dev,
1415                 .pfn            = page_to_pfn(virt_to_page(virt)),
1416                 .offset         = (size_t) virt & PAGE_MASK,
1417                 .dev_addr       = addr,
1418                 .size           = size,
1419                 .direction      = DMA_BIDIRECTIONAL,
1420         };
1421
1422         if (unlikely(global_disable))
1423                 return;
1424
1425         check_unmap(&ref);
1426 }
1427 EXPORT_SYMBOL(debug_dma_free_coherent);
1428
1429 void debug_dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_handle,
1430                                    size_t size, int direction)
1431 {
1432         struct dma_debug_entry ref;
1433
1434         if (unlikely(global_disable))
1435                 return;
1436
1437         ref.type         = dma_debug_single;
1438         ref.dev          = dev;
1439         ref.dev_addr     = dma_handle;
1440         ref.size         = size;
1441         ref.direction    = direction;
1442         ref.sg_call_ents = 0;
1443
1444         check_sync(dev, &ref, true);
1445 }
1446 EXPORT_SYMBOL(debug_dma_sync_single_for_cpu);
1447
1448 void debug_dma_sync_single_for_device(struct device *dev,
1449                                       dma_addr_t dma_handle, size_t size,
1450                                       int direction)
1451 {
1452         struct dma_debug_entry ref;
1453
1454         if (unlikely(global_disable))
1455                 return;
1456
1457         ref.type         = dma_debug_single;
1458         ref.dev          = dev;
1459         ref.dev_addr     = dma_handle;
1460         ref.size         = size;
1461         ref.direction    = direction;
1462         ref.sg_call_ents = 0;
1463
1464         check_sync(dev, &ref, false);
1465 }
1466 EXPORT_SYMBOL(debug_dma_sync_single_for_device);
1467
1468 void debug_dma_sync_single_range_for_cpu(struct device *dev,
1469                                          dma_addr_t dma_handle,
1470                                          unsigned long offset, size_t size,
1471                                          int direction)
1472 {
1473         struct dma_debug_entry ref;
1474
1475         if (unlikely(global_disable))
1476                 return;
1477
1478         ref.type         = dma_debug_single;
1479         ref.dev          = dev;
1480         ref.dev_addr     = dma_handle;
1481         ref.size         = offset + size;
1482         ref.direction    = direction;
1483         ref.sg_call_ents = 0;
1484
1485         check_sync(dev, &ref, true);
1486 }
1487 EXPORT_SYMBOL(debug_dma_sync_single_range_for_cpu);
1488
1489 void debug_dma_sync_single_range_for_device(struct device *dev,
1490                                             dma_addr_t dma_handle,
1491                                             unsigned long offset,
1492                                             size_t size, int direction)
1493 {
1494         struct dma_debug_entry ref;
1495
1496         if (unlikely(global_disable))
1497                 return;
1498
1499         ref.type         = dma_debug_single;
1500         ref.dev          = dev;
1501         ref.dev_addr     = dma_handle;
1502         ref.size         = offset + size;
1503         ref.direction    = direction;
1504         ref.sg_call_ents = 0;
1505
1506         check_sync(dev, &ref, false);
1507 }
1508 EXPORT_SYMBOL(debug_dma_sync_single_range_for_device);
1509
1510 void debug_dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
1511                                int nelems, int direction)
1512 {
1513         struct scatterlist *s;
1514         int mapped_ents = 0, i;
1515
1516         if (unlikely(global_disable))
1517                 return;
1518
1519         for_each_sg(sg, s, nelems, i) {
1520
1521                 struct dma_debug_entry ref = {
1522                         .type           = dma_debug_sg,
1523                         .dev            = dev,
1524                         .pfn            = page_to_pfn(sg_page(s)),
1525                         .offset         = s->offset,
1526                         .dev_addr       = sg_dma_address(s),
1527                         .size           = sg_dma_len(s),
1528                         .direction      = direction,
1529                         .sg_call_ents   = nelems,
1530                 };
1531
1532                 if (!i)
1533                         mapped_ents = get_nr_mapped_entries(dev, &ref);
1534
1535                 if (i >= mapped_ents)
1536                         break;
1537
1538                 check_sync(dev, &ref, true);
1539         }
1540 }
1541 EXPORT_SYMBOL(debug_dma_sync_sg_for_cpu);
1542
1543 void debug_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
1544                                   int nelems, int direction)
1545 {
1546         struct scatterlist *s;
1547         int mapped_ents = 0, i;
1548
1549         if (unlikely(global_disable))
1550                 return;
1551
1552         for_each_sg(sg, s, nelems, i) {
1553
1554                 struct dma_debug_entry ref = {
1555                         .type           = dma_debug_sg,
1556                         .dev            = dev,
1557                         .pfn            = page_to_pfn(sg_page(s)),
1558                         .offset         = s->offset,
1559                         .dev_addr       = sg_dma_address(s),
1560                         .size           = sg_dma_len(s),
1561                         .direction      = direction,
1562                         .sg_call_ents   = nelems,
1563                 };
1564                 if (!i)
1565                         mapped_ents = get_nr_mapped_entries(dev, &ref);
1566
1567                 if (i >= mapped_ents)
1568                         break;
1569
1570                 check_sync(dev, &ref, false);
1571         }
1572 }
1573 EXPORT_SYMBOL(debug_dma_sync_sg_for_device);
1574
1575 static int __init dma_debug_driver_setup(char *str)
1576 {
1577         int i;
1578
1579         for (i = 0; i < NAME_MAX_LEN - 1; ++i, ++str) {
1580                 current_driver_name[i] = *str;
1581                 if (*str == 0)
1582                         break;
1583         }
1584
1585         if (current_driver_name[0])
1586                 pr_info("DMA-API: enable driver filter for driver [%s]\n",
1587                         current_driver_name);
1588
1589
1590         return 1;
1591 }
1592 __setup("dma_debug_driver=", dma_debug_driver_setup);