lib/dma-debug.c

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