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 bool global_disable __read_mostly;
 104
 105 /* Early initialization disable flag, set at the end of dma_debug_init */
 106 static bool dma_debug_initialized __read_mostly;
 107
 108 static inline bool dma_debug_disabled(void)
 109 {
 110         return global_disable || !dma_debug_initialized;
 111 }
 112
 113 /* Global error count */
 114 static u32 error_count;
 115
 116 /* Global error show enable*/
 117 static u32 show_all_errors __read_mostly;
 118 /* Number of errors to show */
 119 static u32 show_num_errors = 1;
 120
 121 static u32 num_free_entries;
 122 static u32 min_free_entries;
 123 static u32 nr_total_entries;
 124
 125 /* number of preallocated entries requested by kernel cmdline */
 126 static u32 req_entries;
 127
 128 /* debugfs dentry's for the stuff above */
 129 static struct dentry *dma_debug_dent        __read_mostly;
 130 static struct dentry *global_disable_dent   __read_mostly;
 131 static struct dentry *error_count_dent      __read_mostly;
 132 static struct dentry *show_all_errors_dent  __read_mostly;
 133 static struct dentry *show_num_errors_dent  __read_mostly;
 134 static struct dentry *num_free_entries_dent __read_mostly;
 135 static struct dentry *min_free_entries_dent __read_mostly;
 136 static struct dentry *filter_dent           __read_mostly;
 137
 138 /* per-driver filter related state */
 139
 140 #define NAME_MAX_LEN    64
 141
 142 static char                  current_driver_name[NAME_MAX_LEN] __read_mostly;
 143 static struct device_driver *current_driver                    __read_mostly;
 144
 145 static DEFINE_RWLOCK(driver_name_lock);
 146
 147 static const char *const maperr2str[] = {
 148         [MAP_ERR_CHECK_NOT_APPLICABLE] = "dma map error check not applicable",
 149         [MAP_ERR_NOT_CHECKED] = "dma map error not checked",
 150         [MAP_ERR_CHECKED] = "dma map error checked",
 151 };
 152
 153 static const char *type2name[4] = { "single", "page",
 154                                     "scather-gather", "coherent" };
 155
 156 static const char *dir2name[4] = { "DMA_BIDIRECTIONAL", "DMA_TO_DEVICE",
 157                                    "DMA_FROM_DEVICE", "DMA_NONE" };
 158
 159 /*
 160  * The access to some variables in this macro is racy. We can't use atomic_t
 161  * here because all these variables are exported to debugfs. Some of them even
 162  * writeable. This is also the reason why a lock won't help much. But anyway,
 163  * the races are no big deal. Here is why:
 164  *
 165  *   error_count: the addition is racy, but the worst thing that can happen is
 166  *                that we don't count some errors
 167  *   show_num_errors: the subtraction is racy. Also no big deal because in
 168  *                    worst case this will result in one warning more in the
 169  *                    system log than the user configured. This variable is
 170  *                    writeable via debugfs.
 171  */
 172 static inline void dump_entry_trace(struct dma_debug_entry *entry)
 173 {
 174 #ifdef CONFIG_STACKTRACE
 175         if (entry) {
 176                 pr_warning("Mapped at:\n");
 177                 print_stack_trace(&entry->stacktrace, 0);
 178         }
 179 #endif
 180 }
 181
 182 static bool driver_filter(struct device *dev)
 183 {
 184         struct device_driver *drv;
 185         unsigned long flags;
 186         bool ret;
 187
 188         /* driver filter off */
 189         if (likely(!current_driver_name[0]))
 190                 return true;
 191
 192         /* driver filter on and initialized */
 193         if (current_driver && dev && dev->driver == current_driver)
 194                 return true;
 195
 196         /* driver filter on, but we can't filter on a NULL device... */
 197         if (!dev)
 198                 return false;
 199
 200         if (current_driver || !current_driver_name[0])
 201                 return false;
 202
 203         /* driver filter on but not yet initialized */
 204         drv = dev->driver;
 205         if (!drv)
 206                 return false;
 207
 208         /* lock to protect against change of current_driver_name */
 209         read_lock_irqsave(&driver_name_lock, flags);
 210
 211         ret = false;
 212         if (drv->name &&
 213             strncmp(current_driver_name, drv->name, NAME_MAX_LEN - 1) == 0) {
 214                 current_driver = drv;
 215                 ret = true;
 216         }
 217
 218         read_unlock_irqrestore(&driver_name_lock, flags);
 219
 220         return ret;
 221 }
 222
 223 #define err_printk(dev, entry, format, arg...) do {                     \
 224                 error_count += 1;                                       \
 225                 if (driver_filter(dev) &&                               \
 226                     (show_all_errors || show_num_errors > 0)) {         \
 227                         WARN(1, "%s %s: " format,                       \
 228                              dev ? dev_driver_string(dev) : "NULL",     \
 229                              dev ? dev_name(dev) : "NULL", ## arg);     \
 230                         dump_entry_trace(entry);                        \
 231                 }                                                       \
 232                 if (!show_all_errors && show_num_errors > 0)            \
 233                         show_num_errors -= 1;                           \
 234         } while (0);
 235
 236 /*
 237  * Hash related functions
 238  *
 239  * Every DMA-API request is saved into a struct dma_debug_entry. To
 240  * have quick access to these structs they are stored into a hash.
 241  */
 242 static int hash_fn(struct dma_debug_entry *entry)
 243 {
 244         /*
 245          * Hash function is based on the dma address.
 246          * We use bits 20-27 here as the index into the hash
 247          */
 248         return (entry->dev_addr >> HASH_FN_SHIFT) & HASH_FN_MASK;
 249 }
 250
 251 /*
 252  * Request exclusive access to a hash bucket for a given dma_debug_entry.
 253  */
 254 static struct hash_bucket *get_hash_bucket(struct dma_debug_entry *entry,
 255                                            unsigned long *flags)
 256 {
 257         int idx = hash_fn(entry);
 258         unsigned long __flags;
 259
 260         spin_lock_irqsave(&dma_entry_hash[idx].lock, __flags);
 261         *flags = __flags;
 262         return &dma_entry_hash[idx];
 263 }
 264
 265 /*
 266  * Give up exclusive access to the hash bucket
 267  */
 268 static void put_hash_bucket(struct hash_bucket *bucket,
 269                             unsigned long *flags)
 270 {
 271         unsigned long __flags = *flags;
 272
 273         spin_unlock_irqrestore(&bucket->lock, __flags);
 274 }
 275
 276 static bool exact_match(struct dma_debug_entry *a, struct dma_debug_entry *b)
 277 {
 278         return ((a->dev_addr == b->dev_addr) &&
 279                 (a->dev == b->dev)) ? true : false;
 280 }
 281
 282 static bool containing_match(struct dma_debug_entry *a,
 283                              struct dma_debug_entry *b)
 284 {
 285         if (a->dev != b->dev)
 286                 return false;
 287
 288         if ((b->dev_addr <= a->dev_addr) &&
 289             ((b->dev_addr + b->size) >= (a->dev_addr + a->size)))
 290                 return true;
 291
 292         return false;
 293 }
 294
 295 /*
 296  * Search a given entry in the hash bucket list
 297  */
 298 static struct dma_debug_entry *__hash_bucket_find(struct hash_bucket *bucket,
 299                                                   struct dma_debug_entry *ref,
 300                                                   match_fn match)
 301 {
 302         struct dma_debug_entry *entry, *ret = NULL;
 303         int matches = 0, match_lvl, last_lvl = -1;
 304
 305         list_for_each_entry(entry, &bucket->list, list) {
 306                 if (!match(ref, entry))
 307                         continue;
 308
 309                 /*
 310                  * Some drivers map the same physical address multiple
 311                  * times. Without a hardware IOMMU this results in the
 312                  * same device addresses being put into the dma-debug
 313                  * hash multiple times too. This can result in false
 314                  * positives being reported. Therefore we implement a
 315                  * best-fit algorithm here which returns the entry from
 316                  * the hash which fits best to the reference value
 317                  * instead of the first-fit.
 318                  */
 319                 matches += 1;
 320                 match_lvl = 0;
 321                 entry->size         == ref->size         ? ++match_lvl : 0;
 322                 entry->type         == ref->type         ? ++match_lvl : 0;
 323                 entry->direction    == ref->direction    ? ++match_lvl : 0;
 324                 entry->sg_call_ents == ref->sg_call_ents ? ++match_lvl : 0;
 325
 326                 if (match_lvl == 4) {
 327                         /* perfect-fit - return the result */
 328                         return entry;
 329                 } else if (match_lvl > last_lvl) {
 330                         /*
 331                          * We found an entry that fits better then the
 332                          * previous one or it is the 1st match.
 333                          */
 334                         last_lvl = match_lvl;
 335                         ret      = entry;
 336                 }
 337         }
 338
 339         /*
 340          * If we have multiple matches but no perfect-fit, just return
 341          * NULL.
 342          */
 343         ret = (matches == 1) ? ret : NULL;
 344
 345         return ret;
 346 }
 347
 348 static struct dma_debug_entry *bucket_find_exact(struct hash_bucket *bucket,
 349                                                  struct dma_debug_entry *ref)
 350 {
 351         return __hash_bucket_find(bucket, ref, exact_match);
 352 }
 353
 354 static struct dma_debug_entry *bucket_find_contain(struct hash_bucket **bucket,
 355                                                    struct dma_debug_entry *ref,
 356                                                    unsigned long *flags)
 357 {
 358
 359         unsigned int max_range = dma_get_max_seg_size(ref->dev);
 360         struct dma_debug_entry *entry, index = *ref;
 361         unsigned int range = 0;
 362
 363         while (range <= max_range) {
 364                 entry = __hash_bucket_find(*bucket, ref, containing_match);
 365
 366                 if (entry)
 367                         return entry;
 368
 369                 /*
 370                  * Nothing found, go back a hash bucket
 371                  */
 372                 put_hash_bucket(*bucket, flags);
 373                 range          += (1 << HASH_FN_SHIFT);
 374                 index.dev_addr -= (1 << HASH_FN_SHIFT);
 375                 *bucket = get_hash_bucket(&index, flags);
 376         }
 377
 378         return NULL;
 379 }
 380
 381 /*
 382  * Add an entry to a hash bucket
 383  */
 384 static void hash_bucket_add(struct hash_bucket *bucket,
 385                             struct dma_debug_entry *entry)
 386 {
 387         list_add_tail(&entry->list, &bucket->list);
 388 }
 389
 390 /*
 391  * Remove entry from a hash bucket list
 392  */
 393 static void hash_bucket_del(struct dma_debug_entry *entry)
 394 {
 395         list_del(&entry->list);
 396 }
 397
 398 static unsigned long long phys_addr(struct dma_debug_entry *entry)
 399 {
 400         return page_to_phys(pfn_to_page(entry->pfn)) + entry->offset;
 401 }
 402
 403 /*
 404  * Dump mapping entries for debugging purposes
 405  */
 406 void debug_dma_dump_mappings(struct device *dev)
 407 {
 408         int idx;
 409
 410         for (idx = 0; idx < HASH_SIZE; idx++) {
 411                 struct hash_bucket *bucket = &dma_entry_hash[idx];
 412                 struct dma_debug_entry *entry;
 413                 unsigned long flags;
 414
 415                 spin_lock_irqsave(&bucket->lock, flags);
 416
 417                 list_for_each_entry(entry, &bucket->list, list) {
 418                         if (!dev || dev == entry->dev) {
 419                                 dev_info(entry->dev,
 420                                          "%s idx %d P=%Lx N=%lx D=%Lx L=%Lx %s %s\n",
 421                                          type2name[entry->type], idx,
 422                                          phys_addr(entry), entry->pfn,
 423                                          entry->dev_addr, entry->size,
 424                                          dir2name[entry->direction],
 425                                          maperr2str[entry->map_err_type]);
 426                         }
 427                 }
 428
 429                 spin_unlock_irqrestore(&bucket->lock, flags);
 430                 cond_resched();
 431         }
 432 }
 433 EXPORT_SYMBOL(debug_dma_dump_mappings);
 434
 435 /*
 436  * For each mapping (initial cacheline in the case of
 437  * dma_alloc_coherent/dma_map_page, initial cacheline in each page of a
 438  * scatterlist, or the cacheline specified in dma_map_single) insert
 439  * into this tree using the cacheline as the key. At
 440  * dma_unmap_{single|sg|page} or dma_free_coherent delete the entry.  If
 441  * the entry already exists at insertion time add a tag as a reference
 442  * count for the overlapping mappings.  For now, the overlap tracking
 443  * just ensures that 'unmaps' balance 'maps' before marking the
 444  * cacheline idle, but we should also be flagging overlaps as an API
 445  * violation.
 446  *
 447  * Memory usage is mostly constrained by the maximum number of available
 448  * dma-debug entries in that we need a free dma_debug_entry before
 449  * inserting into the tree.  In the case of dma_map_page and
 450  * dma_alloc_coherent there is only one dma_debug_entry and one
 451  * dma_active_cacheline entry to track per event.  dma_map_sg(), on the
 452  * other hand, consumes a single dma_debug_entry, but inserts 'nents'
 453  * entries into the tree.
 454  *
 455  * At any time debug_dma_assert_idle() can be called to trigger a
 456  * warning if any cachelines in the given page are in the active set.
 457  */
 458 static RADIX_TREE(dma_active_cacheline, GFP_NOWAIT);
 459 static DEFINE_SPINLOCK(radix_lock);
 460 #define ACTIVE_CACHELINE_MAX_OVERLAP ((1 << RADIX_TREE_MAX_TAGS) - 1)
 461 #define CACHELINE_PER_PAGE_SHIFT (PAGE_SHIFT - L1_CACHE_SHIFT)
 462 #define CACHELINES_PER_PAGE (1 << CACHELINE_PER_PAGE_SHIFT)
 463
 464 static phys_addr_t to_cacheline_number(struct dma_debug_entry *entry)
 465 {
 466         return (entry->pfn << CACHELINE_PER_PAGE_SHIFT) +
 467                 (entry->offset >> L1_CACHE_SHIFT);
 468 }
 469
 470 static int active_cacheline_read_overlap(phys_addr_t cln)
 471 {
 472         int overlap = 0, i;
 473
 474         for (i = RADIX_TREE_MAX_TAGS - 1; i >= 0; i--)
 475                 if (radix_tree_tag_get(&dma_active_cacheline, cln, i))
 476                         overlap |= 1 << i;
 477         return overlap;
 478 }
 479
 480 static int active_cacheline_set_overlap(phys_addr_t cln, int overlap)
 481 {
 482         int i;
 483
 484         if (overlap > ACTIVE_CACHELINE_MAX_OVERLAP || overlap < 0)
 485                 return overlap;
 486
 487         for (i = RADIX_TREE_MAX_TAGS - 1; i >= 0; i--)
 488                 if (overlap & 1 << i)
 489                         radix_tree_tag_set(&dma_active_cacheline, cln, i);
 490                 else
 491                         radix_tree_tag_clear(&dma_active_cacheline, cln, i);
 492
 493         return overlap;
 494 }
 495
 496 static void active_cacheline_inc_overlap(phys_addr_t cln)
 497 {
 498         int overlap = active_cacheline_read_overlap(cln);
 499
 500         overlap = active_cacheline_set_overlap(cln, ++overlap);
 501
 502         /* If we overflowed the overlap counter then we're potentially
 503          * leaking dma-mappings.  Otherwise, if maps and unmaps are
 504          * balanced then this overflow may cause false negatives in
 505          * debug_dma_assert_idle() as the cacheline may be marked idle
 506          * prematurely.
 507          */
 508         WARN_ONCE(overlap > ACTIVE_CACHELINE_MAX_OVERLAP,
 509                   "DMA-API: exceeded %d overlapping mappings of cacheline %pa\n",
 510                   ACTIVE_CACHELINE_MAX_OVERLAP, &cln);
 511 }
 512
 513 static int active_cacheline_dec_overlap(phys_addr_t cln)
 514 {
 515         int overlap = active_cacheline_read_overlap(cln);
 516
 517         return active_cacheline_set_overlap(cln, --overlap);
 518 }
 519
 520 static int active_cacheline_insert(struct dma_debug_entry *entry)
 521 {
 522         phys_addr_t cln = to_cacheline_number(entry);
 523         unsigned long flags;
 524         int rc;
 525
 526         /* If the device is not writing memory then we don't have any
 527          * concerns about the cpu consuming stale data.  This mitigates
 528          * legitimate usages of overlapping mappings.
 529          */
 530         if (entry->direction == DMA_TO_DEVICE)
 531                 return 0;
 532
 533         spin_lock_irqsave(&radix_lock, flags);
 534         rc = radix_tree_insert(&dma_active_cacheline, cln, entry);
 535         if (rc == -EEXIST)
 536                 active_cacheline_inc_overlap(cln);
 537         spin_unlock_irqrestore(&radix_lock, flags);
 538
 539         return rc;
 540 }
 541
 542 static void active_cacheline_remove(struct dma_debug_entry *entry)
 543 {
 544         phys_addr_t cln = to_cacheline_number(entry);
 545         unsigned long flags;
 546
 547         /* ...mirror the insert case */
 548         if (entry->direction == DMA_TO_DEVICE)
 549                 return;
 550
 551         spin_lock_irqsave(&radix_lock, flags);
 552         /* since we are counting overlaps the final put of the
 553          * cacheline will occur when the overlap count is 0.
 554          * active_cacheline_dec_overlap() returns -1 in that case
 555          */
 556         if (active_cacheline_dec_overlap(cln) < 0)
 557                 radix_tree_delete(&dma_active_cacheline, cln);
 558         spin_unlock_irqrestore(&radix_lock, flags);
 559 }
 560
 561 /**
 562  * debug_dma_assert_idle() - assert that a page is not undergoing dma
 563  * @page: page to lookup in the dma_active_cacheline tree
 564  *
 565  * Place a call to this routine in cases where the cpu touching the page
 566  * before the dma completes (page is dma_unmapped) will lead to data
 567  * corruption.
 568  */
 569 void debug_dma_assert_idle(struct page *page)
 570 {
 571         static struct dma_debug_entry *ents[CACHELINES_PER_PAGE];
 572         struct dma_debug_entry *entry = NULL;
 573         void **results = (void **) &ents;
 574         unsigned int nents, i;
 575         unsigned long flags;
 576         phys_addr_t cln;
 577
 578         if (dma_debug_disabled())
 579                 return;
 580
 581         if (!page)
 582                 return;
 583
 584         cln = (phys_addr_t) page_to_pfn(page) << CACHELINE_PER_PAGE_SHIFT;
 585         spin_lock_irqsave(&radix_lock, flags);
 586         nents = radix_tree_gang_lookup(&dma_active_cacheline, results, cln,
 587                                        CACHELINES_PER_PAGE);
 588         for (i = 0; i < nents; i++) {
 589                 phys_addr_t ent_cln = to_cacheline_number(ents[i]);
 590
 591                 if (ent_cln == cln) {
 592                         entry = ents[i];
 593                         break;
 594                 } else if (ent_cln >= cln + CACHELINES_PER_PAGE)
 595                         break;
 596         }
 597         spin_unlock_irqrestore(&radix_lock, flags);
 598
 599         if (!entry)
 600                 return;
 601
 602         cln = to_cacheline_number(entry);
 603         err_printk(entry->dev, entry,
 604                    "DMA-API: cpu touching an active dma mapped cacheline [cln=%pa]\n",
 605                    &cln);
 606 }
 607
 608 /*
 609  * Wrapper function for adding an entry to the hash.
 610  * This function takes care of locking itself.
 611  */
 612 static void add_dma_entry(struct dma_debug_entry *entry)
 613 {
 614         struct hash_bucket *bucket;
 615         unsigned long flags;
 616         int rc;
 617
 618         bucket = get_hash_bucket(entry, &flags);
 619         hash_bucket_add(bucket, entry);
 620         put_hash_bucket(bucket, &flags);
 621
 622         rc = active_cacheline_insert(entry);
 623         if (rc == -ENOMEM) {
 624                 pr_err("DMA-API: cacheline tracking ENOMEM, dma-debug disabled\n");
 625                 global_disable = true;
 626         }
 627
 628         /* TODO: report -EEXIST errors here as overlapping mappings are
 629          * not supported by the DMA API
 630          */
 631 }
 632
 633 static struct dma_debug_entry *__dma_entry_alloc(void)
 634 {
 635         struct dma_debug_entry *entry;
 636
 637         entry = list_entry(free_entries.next, struct dma_debug_entry, list);
 638         list_del(&entry->list);
 639         memset(entry, 0, sizeof(*entry));
 640
 641         num_free_entries -= 1;
 642         if (num_free_entries < min_free_entries)
 643                 min_free_entries = num_free_entries;
 644
 645         return entry;
 646 }
 647
 648 /* struct dma_entry allocator
 649  *
 650  * The next two functions implement the allocator for
 651  * struct dma_debug_entries.
 652  */
 653 static struct dma_debug_entry *dma_entry_alloc(void)
 654 {
 655         struct dma_debug_entry *entry;
 656         unsigned long flags;
 657
 658         spin_lock_irqsave(&free_entries_lock, flags);
 659
 660         if (list_empty(&free_entries)) {
 661                 global_disable = true;
 662                 spin_unlock_irqrestore(&free_entries_lock, flags);
 663                 pr_err("DMA-API: debugging out of memory - disabling\n");
 664                 return NULL;
 665         }
 666
 667         entry = __dma_entry_alloc();
 668
 669         spin_unlock_irqrestore(&free_entries_lock, flags);
 670
 671 #ifdef CONFIG_STACKTRACE
 672         entry->stacktrace.max_entries = DMA_DEBUG_STACKTRACE_ENTRIES;
 673         entry->stacktrace.entries = entry->st_entries;
 674         entry->stacktrace.skip = 2;
 675         save_stack_trace(&entry->stacktrace);
 676 #endif
 677
 678         return entry;
 679 }
 680
 681 static void dma_entry_free(struct dma_debug_entry *entry)
 682 {
 683         unsigned long flags;
 684
 685         active_cacheline_remove(entry);
 686
 687         /*
 688          * add to beginning of the list - this way the entries are
 689          * more likely cache hot when they are reallocated.
 690          */
 691         spin_lock_irqsave(&free_entries_lock, flags);
 692         list_add(&entry->list, &free_entries);
 693         num_free_entries += 1;
 694         spin_unlock_irqrestore(&free_entries_lock, flags);
 695 }
 696
 697 int dma_debug_resize_entries(u32 num_entries)
 698 {
 699         int i, delta, ret = 0;
 700         unsigned long flags;
 701         struct dma_debug_entry *entry;
 702         LIST_HEAD(tmp);
 703
 704         spin_lock_irqsave(&free_entries_lock, flags);
 705
 706         if (nr_total_entries < num_entries) {
 707                 delta = num_entries - nr_total_entries;
 708
 709                 spin_unlock_irqrestore(&free_entries_lock, flags);
 710
 711                 for (i = 0; i < delta; i++) {
 712                         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 713                         if (!entry)
 714                                 break;
 715
 716                         list_add_tail(&entry->list, &tmp);
 717                 }
 718
 719                 spin_lock_irqsave(&free_entries_lock, flags);
 720
 721                 list_splice(&tmp, &free_entries);
 722                 nr_total_entries += i;
 723                 num_free_entries += i;
 724         } else {
 725                 delta = nr_total_entries - num_entries;
 726
 727                 for (i = 0; i < delta && !list_empty(&free_entries); i++) {
 728                         entry = __dma_entry_alloc();
 729                         kfree(entry);
 730                 }
 731
 732                 nr_total_entries -= i;
 733         }
 734
 735         if (nr_total_entries != num_entries)
 736                 ret = 1;
 737
 738         spin_unlock_irqrestore(&free_entries_lock, flags);
 739
 740         return ret;
 741 }
 742 EXPORT_SYMBOL(dma_debug_resize_entries);
 743
 744 /*
 745  * DMA-API debugging init code
 746  *
 747  * The init code does two things:
 748  *   1. Initialize core data structures
 749  *   2. Preallocate a given number of dma_debug_entry structs
 750  */
 751
 752 static int prealloc_memory(u32 num_entries)
 753 {
 754         struct dma_debug_entry *entry, *next_entry;
 755         int i;
 756
 757         for (i = 0; i < num_entries; ++i) {
 758                 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 759                 if (!entry)
 760                         goto out_err;
 761
 762                 list_add_tail(&entry->list, &free_entries);
 763         }
 764
 765         num_free_entries = num_entries;
 766         min_free_entries = num_entries;
 767
 768         pr_info("DMA-API: preallocated %d debug entries\n", num_entries);
 769
 770         return 0;
 771
 772 out_err:
 773
 774         list_for_each_entry_safe(entry, next_entry, &free_entries, list) {
 775                 list_del(&entry->list);
 776                 kfree(entry);
 777         }
 778
 779         return -ENOMEM;
 780 }
 781
 782 static ssize_t filter_read(struct file *file, char __user *user_buf,
 783                            size_t count, loff_t *ppos)
 784 {
 785         char buf[NAME_MAX_LEN + 1];
 786         unsigned long flags;
 787         int len;
 788
 789         if (!current_driver_name[0])
 790                 return 0;
 791
 792         /*
 793          * We can't copy to userspace directly because current_driver_name can
 794          * only be read under the driver_name_lock with irqs disabled. So
 795          * create a temporary copy first.
 796          */
 797         read_lock_irqsave(&driver_name_lock, flags);
 798         len = scnprintf(buf, NAME_MAX_LEN + 1, "%s\n", current_driver_name);
 799         read_unlock_irqrestore(&driver_name_lock, flags);
 800
 801         return simple_read_from_buffer(user_buf, count, ppos, buf, len);
 802 }
 803
 804 static ssize_t filter_write(struct file *file, const char __user *userbuf,
 805                             size_t count, loff_t *ppos)
 806 {
 807         char buf[NAME_MAX_LEN];
 808         unsigned long flags;
 809         size_t len;
 810         int i;
 811
 812         /*
 813          * We can't copy from userspace directly. Access to
 814          * current_driver_name is protected with a write_lock with irqs
 815          * disabled. Since copy_from_user can fault and may sleep we
 816          * need to copy to temporary buffer first
 817          */
 818         len = min(count, (size_t)(NAME_MAX_LEN - 1));
 819         if (copy_from_user(buf, userbuf, len))
 820                 return -EFAULT;
 821
 822         buf[len] = 0;
 823
 824         write_lock_irqsave(&driver_name_lock, flags);
 825
 826         /*
 827          * Now handle the string we got from userspace very carefully.
 828          * The rules are:
 829          *         - only use the first token we got
 830          *         - token delimiter is everything looking like a space
 831          *           character (' ', '\n', '\t' ...)
 832          *
 833          */
 834         if (!isalnum(buf[0])) {
 835                 /*
 836                  * If the first character userspace gave us is not
 837                  * alphanumerical then assume the filter should be
 838                  * switched off.
 839                  */
 840                 if (current_driver_name[0])
 841                         pr_info("DMA-API: switching off dma-debug driver filter\n");
 842                 current_driver_name[0] = 0;
 843                 current_driver = NULL;
 844                 goto out_unlock;
 845         }
 846
 847         /*
 848          * Now parse out the first token and use it as the name for the
 849          * driver to filter for.
 850          */
 851         for (i = 0; i < NAME_MAX_LEN - 1; ++i) {
 852                 current_driver_name[i] = buf[i];
 853                 if (isspace(buf[i]) || buf[i] == ' ' || buf[i] == 0)
 854                         break;
 855         }
 856         current_driver_name[i] = 0;
 857         current_driver = NULL;
 858
 859         pr_info("DMA-API: enable driver filter for driver [%s]\n",
 860                 current_driver_name);
 861
 862 out_unlock:
 863         write_unlock_irqrestore(&driver_name_lock, flags);
 864
 865         return count;
 866 }
 867
 868 static const struct file_operations filter_fops = {
 869         .read  = filter_read,
 870         .write = filter_write,
 871         .llseek = default_llseek,
 872 };
 873
 874 static int dma_debug_fs_init(void)
 875 {
 876         dma_debug_dent = debugfs_create_dir("dma-api", NULL);
 877         if (!dma_debug_dent) {
 878                 pr_err("DMA-API: can not create debugfs directory\n");
 879                 return -ENOMEM;
 880         }
 881
 882         global_disable_dent = debugfs_create_bool("disabled", 0444,
 883                         dma_debug_dent,
 884                         &global_disable);
 885         if (!global_disable_dent)
 886                 goto out_err;
 887
 888         error_count_dent = debugfs_create_u32("error_count", 0444,
 889                         dma_debug_dent, &error_count);
 890         if (!error_count_dent)
 891                 goto out_err;
 892
 893         show_all_errors_dent = debugfs_create_u32("all_errors", 0644,
 894                         dma_debug_dent,
 895                         &show_all_errors);
 896         if (!show_all_errors_dent)
 897                 goto out_err;
 898
 899         show_num_errors_dent = debugfs_create_u32("num_errors", 0644,
 900                         dma_debug_dent,
 901                         &show_num_errors);
 902         if (!show_num_errors_dent)
 903                 goto out_err;
 904
 905         num_free_entries_dent = debugfs_create_u32("num_free_entries", 0444,
 906                         dma_debug_dent,
 907                         &num_free_entries);
 908         if (!num_free_entries_dent)
 909                 goto out_err;
 910
 911         min_free_entries_dent = debugfs_create_u32("min_free_entries", 0444,
 912                         dma_debug_dent,
 913                         &min_free_entries);
 914         if (!min_free_entries_dent)
 915                 goto out_err;
 916
 917         filter_dent = debugfs_create_file("driver_filter", 0644,
 918                                           dma_debug_dent, NULL, &filter_fops);
 919         if (!filter_dent)
 920                 goto out_err;
 921
 922         return 0;
 923
 924 out_err:
 925         debugfs_remove_recursive(dma_debug_dent);
 926
 927         return -ENOMEM;
 928 }
 929
 930 static int device_dma_allocations(struct device *dev, struct dma_debug_entry **out_entry)
 931 {
 932         struct dma_debug_entry *entry;
 933         unsigned long flags;
 934         int count = 0, i;
 935
 936         local_irq_save(flags);
 937
 938         for (i = 0; i < HASH_SIZE; ++i) {
 939                 spin_lock(&dma_entry_hash[i].lock);
 940                 list_for_each_entry(entry, &dma_entry_hash[i].list, list) {
 941                         if (entry->dev == dev) {
 942                                 count += 1;
 943                                 *out_entry = entry;
 944                         }
 945                 }
 946                 spin_unlock(&dma_entry_hash[i].lock);
 947         }
 948
 949         local_irq_restore(flags);
 950
 951         return count;
 952 }
 953
 954 static int dma_debug_device_change(struct notifier_block *nb, unsigned long action, void *data)
 955 {
 956         struct device *dev = data;
 957         struct dma_debug_entry *uninitialized_var(entry);
 958         int count;
 959
 960         if (dma_debug_disabled())
 961                 return 0;
 962
 963         switch (action) {
 964         case BUS_NOTIFY_UNBOUND_DRIVER:
 965                 count = device_dma_allocations(dev, &entry);
 966                 if (count == 0)
 967                         break;
 968                 err_printk(dev, entry, "DMA-API: device driver has pending "
 969                                 "DMA allocations while released from device "
 970                                 "[count=%d]\n"
 971                                 "One of leaked entries details: "
 972                                 "[device address=0x%016llx] [size=%llu bytes] "
 973                                 "[mapped with %s] [mapped as %s]\n",
 974                         count, entry->dev_addr, entry->size,
 975                         dir2name[entry->direction], type2name[entry->type]);
 976                 break;
 977         default:
 978                 break;
 979         }
 980
 981         return 0;
 982 }
 983
 984 void dma_debug_add_bus(struct bus_type *bus)
 985 {
 986         struct notifier_block *nb;
 987
 988         if (dma_debug_disabled())
 989                 return;
 990
 991         nb = kzalloc(sizeof(struct notifier_block), GFP_KERNEL);
 992         if (nb == NULL) {
 993                 pr_err("dma_debug_add_bus: out of memory\n");
 994                 return;
 995         }
 996
 997         nb->notifier_call = dma_debug_device_change;
 998
 999         bus_register_notifier(bus, nb);
1000 }
1001
1002 /*
1003  * Let the architectures decide how many entries should be preallocated.
1004  */
1005 void dma_debug_init(u32 num_entries)
1006 {
1007         int i;
1008
1009         /* Do not use dma_debug_initialized here, since we really want to be
1010          * called to set dma_debug_initialized
1011          */
1012         if (global_disable)
1013                 return;
1014
1015         for (i = 0; i < HASH_SIZE; ++i) {
1016                 INIT_LIST_HEAD(&dma_entry_hash[i].list);
1017                 spin_lock_init(&dma_entry_hash[i].lock);
1018         }
1019
1020         if (dma_debug_fs_init() != 0) {
1021                 pr_err("DMA-API: error creating debugfs entries - disabling\n");
1022                 global_disable = true;
1023
1024                 return;
1025         }
1026
1027         if (req_entries)
1028                 num_entries = req_entries;
1029
1030         if (prealloc_memory(num_entries) != 0) {
1031                 pr_err("DMA-API: debugging out of memory error - disabled\n");
1032                 global_disable = true;
1033
1034                 return;
1035         }
1036
1037         nr_total_entries = num_free_entries;
1038
1039         dma_debug_initialized = true;
1040
1041         pr_info("DMA-API: debugging enabled by kernel config\n");
1042 }
1043
1044 static __init int dma_debug_cmdline(char *str)
1045 {
1046         if (!str)
1047                 return -EINVAL;
1048
1049         if (strncmp(str, "off", 3) == 0) {
1050                 pr_info("DMA-API: debugging disabled on kernel command line\n");
1051                 global_disable = true;
1052         }
1053
1054         return 0;
1055 }
1056
1057 static __init int dma_debug_entries_cmdline(char *str)
1058 {
1059         int res;
1060
1061         if (!str)
1062                 return -EINVAL;
1063
1064         res = get_option(&str, &req_entries);
1065
1066         if (!res)
1067                 req_entries = 0;
1068
1069         return 0;
1070 }
1071
1072 __setup("dma_debug=", dma_debug_cmdline);
1073 __setup("dma_debug_entries=", dma_debug_entries_cmdline);
1074
1075 static void check_unmap(struct dma_debug_entry *ref)
1076 {
1077         struct dma_debug_entry *entry;
1078         struct hash_bucket *bucket;
1079         unsigned long flags;
1080
1081         bucket = get_hash_bucket(ref, &flags);
1082         entry = bucket_find_exact(bucket, ref);
1083
1084         if (!entry) {
1085                 /* must drop lock before calling dma_mapping_error */
1086                 put_hash_bucket(bucket, &flags);
1087
1088                 if (dma_mapping_error(ref->dev, ref->dev_addr)) {
1089                         err_printk(ref->dev, NULL,
1090                                    "DMA-API: device driver tries to free an "
1091                                    "invalid DMA memory address\n");
1092                 } else {
1093                         err_printk(ref->dev, NULL,
1094                                    "DMA-API: device driver tries to free DMA "
1095                                    "memory it has not allocated [device "
1096                                    "address=0x%016llx] [size=%llu bytes]\n",
1097                                    ref->dev_addr, ref->size);
1098                 }
1099                 return;
1100         }
1101
1102         if (ref->size != entry->size) {
1103                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
1104                            "DMA memory with different size "
1105                            "[device address=0x%016llx] [map size=%llu bytes] "
1106                            "[unmap size=%llu bytes]\n",
1107                            ref->dev_addr, entry->size, ref->size);
1108         }
1109
1110         if (ref->type != entry->type) {
1111                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
1112                            "DMA memory with wrong function "
1113                            "[device address=0x%016llx] [size=%llu bytes] "
1114                            "[mapped as %s] [unmapped as %s]\n",
1115                            ref->dev_addr, ref->size,
1116                            type2name[entry->type], type2name[ref->type]);
1117         } else if ((entry->type == dma_debug_coherent) &&
1118                    (phys_addr(ref) != phys_addr(entry))) {
1119                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
1120                            "DMA memory with different CPU address "
1121                            "[device address=0x%016llx] [size=%llu bytes] "
1122                            "[cpu alloc address=0x%016llx] "
1123                            "[cpu free address=0x%016llx]",
1124                            ref->dev_addr, ref->size,
1125                            phys_addr(entry),
1126                            phys_addr(ref));
1127         }
1128
1129         if (ref->sg_call_ents && ref->type == dma_debug_sg &&
1130             ref->sg_call_ents != entry->sg_call_ents) {
1131                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
1132                            "DMA sg list with different entry count "
1133                            "[map count=%d] [unmap count=%d]\n",
1134                            entry->sg_call_ents, ref->sg_call_ents);
1135         }
1136
1137         /*
1138          * This may be no bug in reality - but most implementations of the
1139          * DMA API don't handle this properly, so check for it here
1140          */
1141         if (ref->direction != entry->direction) {
1142                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
1143                            "DMA memory with different direction "
1144                            "[device address=0x%016llx] [size=%llu bytes] "
1145                            "[mapped with %s] [unmapped with %s]\n",
1146                            ref->dev_addr, ref->size,
1147                            dir2name[entry->direction],
1148                            dir2name[ref->direction]);
1149         }
1150
1151         if (entry->map_err_type == MAP_ERR_NOT_CHECKED) {
1152                 err_printk(ref->dev, entry,
1153                            "DMA-API: device driver failed to check map error"
1154                            "[device address=0x%016llx] [size=%llu bytes] "
1155                            "[mapped as %s]",
1156                            ref->dev_addr, ref->size,
1157                            type2name[entry->type]);
1158         }
1159
1160         hash_bucket_del(entry);
1161         dma_entry_free(entry);
1162
1163         put_hash_bucket(bucket, &flags);
1164 }
1165
1166 static void check_for_stack(struct device *dev, void *addr)
1167 {
1168         if (object_is_on_stack(addr))
1169                 err_printk(dev, NULL, "DMA-API: device driver maps memory from "
1170                                 "stack [addr=%p]\n", addr);
1171 }
1172
1173 static inline bool overlap(void *addr, unsigned long len, void *start, void *end)
1174 {
1175         unsigned long a1 = (unsigned long)addr;
1176         unsigned long b1 = a1 + len;
1177         unsigned long a2 = (unsigned long)start;
1178         unsigned long b2 = (unsigned long)end;
1179
1180         return !(b1 <= a2 || a1 >= b2);
1181 }
1182
1183 static void check_for_illegal_area(struct device *dev, void *addr, unsigned long len)
1184 {
1185         if (overlap(addr, len, _stext, _etext) ||
1186             overlap(addr, len, __start_rodata, __end_rodata))
1187                 err_printk(dev, NULL, "DMA-API: device driver maps memory from kernel text or rodata [addr=%p] [len=%lu]\n", addr, len);
1188 }
1189
1190 static void check_sync(struct device *dev,
1191                        struct dma_debug_entry *ref,
1192                        bool to_cpu)
1193 {
1194         struct dma_debug_entry *entry;
1195         struct hash_bucket *bucket;
1196         unsigned long flags;
1197
1198         bucket = get_hash_bucket(ref, &flags);
1199
1200         entry = bucket_find_contain(&bucket, ref, &flags);
1201
1202         if (!entry) {
1203                 err_printk(dev, NULL, "DMA-API: device driver tries "
1204                                 "to sync DMA memory it has not allocated "
1205                                 "[device address=0x%016llx] [size=%llu bytes]\n",
1206                                 (unsigned long long)ref->dev_addr, ref->size);
1207                 goto out;
1208         }
1209
1210         if (ref->size > entry->size) {
1211                 err_printk(dev, entry, "DMA-API: device driver syncs"
1212                                 " DMA memory outside allocated range "
1213                                 "[device address=0x%016llx] "
1214                                 "[allocation size=%llu bytes] "
1215                                 "[sync offset+size=%llu]\n",
1216                                 entry->dev_addr, entry->size,
1217                                 ref->size);
1218         }
1219
1220         if (entry->direction == DMA_BIDIRECTIONAL)
1221                 goto out;
1222
1223         if (ref->direction != entry->direction) {
1224                 err_printk(dev, entry, "DMA-API: device driver syncs "
1225                                 "DMA memory with different direction "
1226                                 "[device address=0x%016llx] [size=%llu bytes] "
1227                                 "[mapped with %s] [synced with %s]\n",
1228                                 (unsigned long long)ref->dev_addr, entry->size,
1229                                 dir2name[entry->direction],
1230                                 dir2name[ref->direction]);
1231         }
1232
1233         if (to_cpu && !(entry->direction == DMA_FROM_DEVICE) &&
1234                       !(ref->direction == DMA_TO_DEVICE))
1235                 err_printk(dev, entry, "DMA-API: device driver syncs "
1236                                 "device read-only DMA memory for cpu "
1237                                 "[device address=0x%016llx] [size=%llu bytes] "
1238                                 "[mapped with %s] [synced with %s]\n",
1239                                 (unsigned long long)ref->dev_addr, entry->size,
1240                                 dir2name[entry->direction],
1241                                 dir2name[ref->direction]);
1242
1243         if (!to_cpu && !(entry->direction == DMA_TO_DEVICE) &&
1244                        !(ref->direction == DMA_FROM_DEVICE))
1245                 err_printk(dev, entry, "DMA-API: device driver syncs "
1246                                 "device write-only DMA memory to device "
1247                                 "[device address=0x%016llx] [size=%llu bytes] "
1248                                 "[mapped with %s] [synced with %s]\n",
1249                                 (unsigned long long)ref->dev_addr, entry->size,
1250                                 dir2name[entry->direction],
1251                                 dir2name[ref->direction]);
1252
1253         if (ref->sg_call_ents && ref->type == dma_debug_sg &&
1254             ref->sg_call_ents != entry->sg_call_ents) {
1255                 err_printk(ref->dev, entry, "DMA-API: device driver syncs "
1256                            "DMA sg list with different entry count "
1257                            "[map count=%d] [sync count=%d]\n",
1258                            entry->sg_call_ents, ref->sg_call_ents);
1259         }
1260
1261 out:
1262         put_hash_bucket(bucket, &flags);
1263 }
1264
1265 void debug_dma_map_page(struct device *dev, struct page *page, size_t offset,
1266                         size_t size, int direction, dma_addr_t dma_addr,
1267                         bool map_single)
1268 {
1269         struct dma_debug_entry *entry;
1270
1271         if (unlikely(dma_debug_disabled()))
1272                 return;
1273
1274         if (dma_mapping_error(dev, dma_addr))
1275                 return;
1276
1277         entry = dma_entry_alloc();
1278         if (!entry)
1279                 return;
1280
1281         entry->dev       = dev;
1282         entry->type      = dma_debug_page;
1283         entry->pfn       = page_to_pfn(page);
1284         entry->offset    = offset,
1285         entry->dev_addr  = dma_addr;
1286         entry->size      = size;
1287         entry->direction = direction;
1288         entry->map_err_type = MAP_ERR_NOT_CHECKED;
1289
1290         if (map_single)
1291                 entry->type = dma_debug_single;
1292
1293         if (!PageHighMem(page)) {
1294                 void *addr = page_address(page) + offset;
1295
1296                 check_for_stack(dev, addr);
1297                 check_for_illegal_area(dev, addr, size);
1298         }
1299
1300         add_dma_entry(entry);
1301 }
1302 EXPORT_SYMBOL(debug_dma_map_page);
1303
1304 void debug_dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
1305 {
1306         struct dma_debug_entry ref;
1307         struct dma_debug_entry *entry;
1308         struct hash_bucket *bucket;
1309         unsigned long flags;
1310
1311         if (unlikely(dma_debug_disabled()))
1312                 return;
1313
1314         ref.dev = dev;
1315         ref.dev_addr = dma_addr;
1316         bucket = get_hash_bucket(&ref, &flags);
1317
1318         list_for_each_entry(entry, &bucket->list, list) {
1319                 if (!exact_match(&ref, entry))
1320                         continue;
1321
1322                 /*
1323                  * The same physical address can be mapped multiple
1324                  * times. Without a hardware IOMMU this results in the
1325                  * same device addresses being put into the dma-debug
1326                  * hash multiple times too. This can result in false
1327                  * positives being reported. Therefore we implement a
1328                  * best-fit algorithm here which updates the first entry
1329                  * from the hash which fits the reference value and is
1330                  * not currently listed as being checked.
1331                  */
1332                 if (entry->map_err_type == MAP_ERR_NOT_CHECKED) {
1333                         entry->map_err_type = MAP_ERR_CHECKED;
1334                         break;
1335                 }
1336         }
1337
1338         put_hash_bucket(bucket, &flags);
1339 }
1340 EXPORT_SYMBOL(debug_dma_mapping_error);
1341
1342 void debug_dma_unmap_page(struct device *dev, dma_addr_t addr,
1343                           size_t size, int direction, bool map_single)
1344 {
1345         struct dma_debug_entry ref = {
1346                 .type           = dma_debug_page,
1347                 .dev            = dev,
1348                 .dev_addr       = addr,
1349                 .size           = size,
1350                 .direction      = direction,
1351         };
1352
1353         if (unlikely(dma_debug_disabled()))
1354                 return;
1355
1356         if (map_single)
1357                 ref.type = dma_debug_single;
1358
1359         check_unmap(&ref);
1360 }
1361 EXPORT_SYMBOL(debug_dma_unmap_page);
1362
1363 void debug_dma_map_sg(struct device *dev, struct scatterlist *sg,
1364                       int nents, int mapped_ents, int direction)
1365 {
1366         struct dma_debug_entry *entry;
1367         struct scatterlist *s;
1368         int i;
1369
1370         if (unlikely(dma_debug_disabled()))
1371                 return;
1372
1373         for_each_sg(sg, s, mapped_ents, i) {
1374                 entry = dma_entry_alloc();
1375                 if (!entry)
1376                         return;
1377
1378                 entry->type           = dma_debug_sg;
1379                 entry->dev            = dev;
1380                 entry->pfn            = page_to_pfn(sg_page(s));
1381                 entry->offset         = s->offset,
1382                 entry->size           = sg_dma_len(s);
1383                 entry->dev_addr       = sg_dma_address(s);
1384                 entry->direction      = direction;
1385                 entry->sg_call_ents   = nents;
1386                 entry->sg_mapped_ents = mapped_ents;
1387
1388                 if (!PageHighMem(sg_page(s))) {
1389                         check_for_stack(dev, sg_virt(s));
1390                         check_for_illegal_area(dev, sg_virt(s), sg_dma_len(s));
1391                 }
1392
1393                 add_dma_entry(entry);
1394         }
1395 }
1396 EXPORT_SYMBOL(debug_dma_map_sg);
1397
1398 static int get_nr_mapped_entries(struct device *dev,
1399                                  struct dma_debug_entry *ref)
1400 {
1401         struct dma_debug_entry *entry;
1402         struct hash_bucket *bucket;
1403         unsigned long flags;
1404         int mapped_ents;
1405
1406         bucket       = get_hash_bucket(ref, &flags);
1407         entry        = bucket_find_exact(bucket, ref);
1408         mapped_ents  = 0;
1409
1410         if (entry)
1411                 mapped_ents = entry->sg_mapped_ents;
1412         put_hash_bucket(bucket, &flags);
1413
1414         return mapped_ents;
1415 }
1416
1417 void debug_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
1418                         int nelems, int dir)
1419 {
1420         struct scatterlist *s;
1421         int mapped_ents = 0, i;
1422
1423         if (unlikely(dma_debug_disabled()))
1424                 return;
1425
1426         for_each_sg(sglist, s, nelems, i) {
1427
1428                 struct dma_debug_entry ref = {
1429                         .type           = dma_debug_sg,
1430                         .dev            = dev,
1431                         .pfn            = page_to_pfn(sg_page(s)),
1432                         .offset         = s->offset,
1433                         .dev_addr       = sg_dma_address(s),
1434                         .size           = sg_dma_len(s),
1435                         .direction      = dir,
1436                         .sg_call_ents   = nelems,
1437                 };
1438
1439                 if (mapped_ents && i >= mapped_ents)
1440                         break;
1441
1442                 if (!i)
1443                         mapped_ents = get_nr_mapped_entries(dev, &ref);
1444
1445                 check_unmap(&ref);
1446         }
1447 }
1448 EXPORT_SYMBOL(debug_dma_unmap_sg);
1449
1450 void debug_dma_alloc_coherent(struct device *dev, size_t size,
1451                               dma_addr_t dma_addr, void *virt)
1452 {
1453         struct dma_debug_entry *entry;
1454
1455         if (unlikely(dma_debug_disabled()))
1456                 return;
1457
1458         if (unlikely(virt == NULL))
1459                 return;
1460
1461         entry = dma_entry_alloc();
1462         if (!entry)
1463                 return;
1464
1465         entry->type      = dma_debug_coherent;
1466         entry->dev       = dev;
1467         entry->pfn       = page_to_pfn(virt_to_page(virt));
1468         entry->offset    = (size_t) virt & ~PAGE_MASK;
1469         entry->size      = size;
1470         entry->dev_addr  = dma_addr;
1471         entry->direction = DMA_BIDIRECTIONAL;
1472
1473         add_dma_entry(entry);
1474 }
1475 EXPORT_SYMBOL(debug_dma_alloc_coherent);
1476
1477 void debug_dma_free_coherent(struct device *dev, size_t size,
1478                          void *virt, dma_addr_t addr)
1479 {
1480         struct dma_debug_entry ref = {
1481                 .type           = dma_debug_coherent,
1482                 .dev            = dev,
1483                 .pfn            = page_to_pfn(virt_to_page(virt)),
1484                 .offset         = (size_t) virt & ~PAGE_MASK,
1485                 .dev_addr       = addr,
1486                 .size           = size,
1487                 .direction      = DMA_BIDIRECTIONAL,
1488         };
1489
1490         if (unlikely(dma_debug_disabled()))
1491                 return;
1492
1493         check_unmap(&ref);
1494 }
1495 EXPORT_SYMBOL(debug_dma_free_coherent);
1496
1497 void debug_dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_handle,
1498                                    size_t size, int direction)
1499 {
1500         struct dma_debug_entry ref;
1501
1502         if (unlikely(dma_debug_disabled()))
1503                 return;
1504
1505         ref.type         = dma_debug_single;
1506         ref.dev          = dev;
1507         ref.dev_addr     = dma_handle;
1508         ref.size         = size;
1509         ref.direction    = direction;
1510         ref.sg_call_ents = 0;
1511
1512         check_sync(dev, &ref, true);
1513 }
1514 EXPORT_SYMBOL(debug_dma_sync_single_for_cpu);
1515
1516 void debug_dma_sync_single_for_device(struct device *dev,
1517                                       dma_addr_t dma_handle, size_t size,
1518                                       int direction)
1519 {
1520         struct dma_debug_entry ref;
1521
1522         if (unlikely(dma_debug_disabled()))
1523                 return;
1524
1525         ref.type         = dma_debug_single;
1526         ref.dev          = dev;
1527         ref.dev_addr     = dma_handle;
1528         ref.size         = size;
1529         ref.direction    = direction;
1530         ref.sg_call_ents = 0;
1531
1532         check_sync(dev, &ref, false);
1533 }
1534 EXPORT_SYMBOL(debug_dma_sync_single_for_device);
1535
1536 void debug_dma_sync_single_range_for_cpu(struct device *dev,
1537                                          dma_addr_t dma_handle,
1538                                          unsigned long offset, size_t size,
1539                                          int direction)
1540 {
1541         struct dma_debug_entry ref;
1542
1543         if (unlikely(dma_debug_disabled()))
1544                 return;
1545
1546         ref.type         = dma_debug_single;
1547         ref.dev          = dev;
1548         ref.dev_addr     = dma_handle;
1549         ref.size         = offset + size;
1550         ref.direction    = direction;
1551         ref.sg_call_ents = 0;
1552
1553         check_sync(dev, &ref, true);
1554 }
1555 EXPORT_SYMBOL(debug_dma_sync_single_range_for_cpu);
1556
1557 void debug_dma_sync_single_range_for_device(struct device *dev,
1558                                             dma_addr_t dma_handle,
1559                                             unsigned long offset,
1560                                             size_t size, int direction)
1561 {
1562         struct dma_debug_entry ref;
1563
1564         if (unlikely(dma_debug_disabled()))
1565                 return;
1566
1567         ref.type         = dma_debug_single;
1568         ref.dev          = dev;
1569         ref.dev_addr     = dma_handle;
1570         ref.size         = offset + size;
1571         ref.direction    = direction;
1572         ref.sg_call_ents = 0;
1573
1574         check_sync(dev, &ref, false);
1575 }
1576 EXPORT_SYMBOL(debug_dma_sync_single_range_for_device);
1577
1578 void debug_dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
1579                                int nelems, int direction)
1580 {
1581         struct scatterlist *s;
1582         int mapped_ents = 0, i;
1583
1584         if (unlikely(dma_debug_disabled()))
1585                 return;
1586
1587         for_each_sg(sg, s, nelems, i) {
1588
1589                 struct dma_debug_entry ref = {
1590                         .type           = dma_debug_sg,
1591                         .dev            = dev,
1592                         .pfn            = page_to_pfn(sg_page(s)),
1593                         .offset         = s->offset,
1594                         .dev_addr       = sg_dma_address(s),
1595                         .size           = sg_dma_len(s),
1596                         .direction      = direction,
1597                         .sg_call_ents   = nelems,
1598                 };
1599
1600                 if (!i)
1601                         mapped_ents = get_nr_mapped_entries(dev, &ref);
1602
1603                 if (i >= mapped_ents)
1604                         break;
1605
1606                 check_sync(dev, &ref, true);
1607         }
1608 }
1609 EXPORT_SYMBOL(debug_dma_sync_sg_for_cpu);
1610
1611 void debug_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
1612                                   int nelems, int direction)
1613 {
1614         struct scatterlist *s;
1615         int mapped_ents = 0, i;
1616
1617         if (unlikely(dma_debug_disabled()))
1618                 return;
1619
1620         for_each_sg(sg, s, nelems, i) {
1621
1622                 struct dma_debug_entry ref = {
1623                         .type           = dma_debug_sg,
1624                         .dev            = dev,
1625                         .pfn            = page_to_pfn(sg_page(s)),
1626                         .offset         = s->offset,
1627                         .dev_addr       = sg_dma_address(s),
1628                         .size           = sg_dma_len(s),
1629                         .direction      = direction,
1630                         .sg_call_ents   = nelems,
1631                 };
1632                 if (!i)
1633                         mapped_ents = get_nr_mapped_entries(dev, &ref);
1634
1635                 if (i >= mapped_ents)
1636                         break;
1637
1638                 check_sync(dev, &ref, false);
1639         }
1640 }
1641 EXPORT_SYMBOL(debug_dma_sync_sg_for_device);
1642
1643 static int __init dma_debug_driver_setup(char *str)
1644 {
1645         int i;
1646
1647         for (i = 0; i < NAME_MAX_LEN - 1; ++i, ++str) {
1648                 current_driver_name[i] = *str;
1649                 if (*str == 0)
1650                         break;
1651         }
1652
1653         if (current_driver_name[0])
1654                 pr_info("DMA-API: enable driver filter for driver [%s]\n",
1655                         current_driver_name);
1656
1657
1658         return 1;
1659 }
1660 __setup("dma_debug_driver=", dma_debug_driver_setup);