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