kernel/dma/debug.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2008 Advanced Micro Devices, Inc.
   4  *
   5  * Author: Joerg Roedel <joerg.roedel@amd.com>
   6  */
   7
   8 #define pr_fmt(fmt)     "DMA-API: " fmt
   9
  10 #include <linux/sched/task_stack.h>
  11 #include <linux/scatterlist.h>
  12 #include <linux/dma-mapping.h>
  13 #include <linux/sched/task.h>
  14 #include <linux/stacktrace.h>
  15 #include <linux/dma-debug.h>
  16 #include <linux/spinlock.h>
  17 #include <linux/vmalloc.h>
  18 #include <linux/debugfs.h>
  19 #include <linux/uaccess.h>
  20 #include <linux/export.h>
  21 #include <linux/device.h>
  22 #include <linux/types.h>
  23 #include <linux/sched.h>
  24 #include <linux/ctype.h>
  25 #include <linux/list.h>
  26 #include <linux/slab.h>
  27
  28 #include <asm/sections.h>
  29
  30 #define HASH_SIZE       16384ULL
  31 #define HASH_FN_SHIFT   13
  32 #define HASH_FN_MASK    (HASH_SIZE - 1)
  33
  34 #define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16)
  35 /* If the pool runs out, add this many new entries at once */
  36 #define DMA_DEBUG_DYNAMIC_ENTRIES (PAGE_SIZE / sizeof(struct dma_debug_entry))
  37
  38 enum {
  39         dma_debug_single,
  40         dma_debug_sg,
  41         dma_debug_coherent,
  42         dma_debug_resource,
  43 };
  44
  45 enum map_err_types {
  46         MAP_ERR_CHECK_NOT_APPLICABLE,
  47         MAP_ERR_NOT_CHECKED,
  48         MAP_ERR_CHECKED,
  49 };
  50
  51 #define DMA_DEBUG_STACKTRACE_ENTRIES 5
  52
  53 /**
  54  * struct dma_debug_entry - track a dma_map* or dma_alloc_coherent mapping
  55  * @list: node on pre-allocated free_entries list
  56  * @dev: 'dev' argument to dma_map_{page|single|sg} or dma_alloc_coherent
  57  * @size: length of the mapping
  58  * @type: single, page, sg, coherent
  59  * @direction: enum dma_data_direction
  60  * @sg_call_ents: 'nents' from dma_map_sg
  61  * @sg_mapped_ents: 'mapped_ents' from dma_map_sg
  62  * @pfn: page frame of the start address
  63  * @offset: offset of mapping relative to pfn
  64  * @map_err_type: track whether dma_mapping_error() was checked
  65  * @stacktrace: support backtraces when a violation is detected
  66  */
  67 struct dma_debug_entry {
  68         struct list_head list;
  69         struct device    *dev;
  70         u64              dev_addr;
  71         u64              size;
  72         int              type;
  73         int              direction;
  74         int              sg_call_ents;
  75         int              sg_mapped_ents;
  76         unsigned long    pfn;
  77         size_t           offset;
  78         enum map_err_types  map_err_type;
  79 #ifdef CONFIG_STACKTRACE
  80         unsigned int    stack_len;
  81         unsigned long   stack_entries[DMA_DEBUG_STACKTRACE_ENTRIES];
  82 #endif
  83 } ____cacheline_aligned_in_smp;
  84
  85 typedef bool (*match_fn)(struct dma_debug_entry *, struct dma_debug_entry *);
  86
  87 struct hash_bucket {
  88         struct list_head list;
  89         spinlock_t lock;
  90 };
  91
  92 /* Hash list to save the allocated dma addresses */
  93 static struct hash_bucket dma_entry_hash[HASH_SIZE];
  94 /* List of pre-allocated dma_debug_entry's */
  95 static LIST_HEAD(free_entries);
  96 /* Lock for the list above */
  97 static DEFINE_SPINLOCK(free_entries_lock);
  98
  99 /* Global disable flag - will be set in case of an error */
 100 static bool global_disable __read_mostly;
 101
 102 /* Early initialization disable flag, set at the end of dma_debug_init */
 103 static bool dma_debug_initialized __read_mostly;
 104
 105 static inline bool dma_debug_disabled(void)
 106 {
 107         return global_disable || !dma_debug_initialized;
 108 }
 109
 110 /* Global error count */
 111 static u32 error_count;
 112
 113 /* Global error show enable*/
 114 static u32 show_all_errors __read_mostly;
 115 /* Number of errors to show */
 116 static u32 show_num_errors = 1;
 117
 118 static u32 num_free_entries;
 119 static u32 min_free_entries;
 120 static u32 nr_total_entries;
 121
 122 /* number of preallocated entries requested by kernel cmdline */
 123 static u32 nr_prealloc_entries = PREALLOC_DMA_DEBUG_ENTRIES;
 124
 125 /* per-driver filter related state */
 126
 127 #define NAME_MAX_LEN    64
 128
 129 static char                  current_driver_name[NAME_MAX_LEN] __read_mostly;
 130 static struct device_driver *current_driver                    __read_mostly;
 131
 132 static DEFINE_RWLOCK(driver_name_lock);
 133
 134 static const char *const maperr2str[] = {
 135         [MAP_ERR_CHECK_NOT_APPLICABLE] = "dma map error check not applicable",
 136         [MAP_ERR_NOT_CHECKED] = "dma map error not checked",
 137         [MAP_ERR_CHECKED] = "dma map error checked",
 138 };
 139
 140 static const char *type2name[5] = { "single", "page",
 141                                     "scather-gather", "coherent",
 142                                     "resource" };
 143
 144 static const char *dir2name[4] = { "DMA_BIDIRECTIONAL", "DMA_TO_DEVICE",
 145                                    "DMA_FROM_DEVICE", "DMA_NONE" };
 146
 147 /*
 148  * The access to some variables in this macro is racy. We can't use atomic_t
 149  * here because all these variables are exported to debugfs. Some of them even
 150  * writeable. This is also the reason why a lock won't help much. But anyway,
 151  * the races are no big deal. Here is why:
 152  *
 153  *   error_count: the addition is racy, but the worst thing that can happen is
 154  *                that we don't count some errors
 155  *   show_num_errors: the subtraction is racy. Also no big deal because in
 156  *                    worst case this will result in one warning more in the
 157  *                    system log than the user configured. This variable is
 158  *                    writeable via debugfs.
 159  */
 160 static inline void dump_entry_trace(struct dma_debug_entry *entry)
 161 {
 162 #ifdef CONFIG_STACKTRACE
 163         if (entry) {
 164                 pr_warning("Mapped at:\n");
 165                 stack_trace_print(entry->stack_entries, entry->stack_len, 0);
 166         }
 167 #endif
 168 }
 169
 170 static bool driver_filter(struct device *dev)
 171 {
 172         struct device_driver *drv;
 173         unsigned long flags;
 174         bool ret;
 175
 176         /* driver filter off */
 177         if (likely(!current_driver_name[0]))
 178                 return true;
 179
 180         /* driver filter on and initialized */
 181         if (current_driver && dev && dev->driver == current_driver)
 182                 return true;
 183
 184         /* driver filter on, but we can't filter on a NULL device... */
 185         if (!dev)
 186                 return false;
 187
 188         if (current_driver || !current_driver_name[0])
 189                 return false;
 190
 191         /* driver filter on but not yet initialized */
 192         drv = dev->driver;
 193         if (!drv)
 194                 return false;
 195
 196         /* lock to protect against change of current_driver_name */
 197         read_lock_irqsave(&driver_name_lock, flags);
 198
 199         ret = false;
 200         if (drv->name &&
 201             strncmp(current_driver_name, drv->name, NAME_MAX_LEN - 1) == 0) {
 202                 current_driver = drv;
 203                 ret = true;
 204         }
 205
 206         read_unlock_irqrestore(&driver_name_lock, flags);
 207
 208         return ret;
 209 }
 210
 211 #define err_printk(dev, entry, format, arg...) do {                     \
 212                 error_count += 1;                                       \
 213                 if (driver_filter(dev) &&                               \
 214                     (show_all_errors || show_num_errors > 0)) {         \
 215                         WARN(1, pr_fmt("%s %s: ") format,               \
 216                              dev ? dev_driver_string(dev) : "NULL",     \
 217                              dev ? dev_name(dev) : "NULL", ## arg);     \
 218                         dump_entry_trace(entry);                        \
 219                 }                                                       \
 220                 if (!show_all_errors && show_num_errors > 0)            \
 221                         show_num_errors -= 1;                           \
 222         } while (0);
 223
 224 /*
 225  * Hash related functions
 226  *
 227  * Every DMA-API request is saved into a struct dma_debug_entry. To
 228  * have quick access to these structs they are stored into a hash.
 229  */
 230 static int hash_fn(struct dma_debug_entry *entry)
 231 {
 232         /*
 233          * Hash function is based on the dma address.
 234          * We use bits 20-27 here as the index into the hash
 235          */
 236         return (entry->dev_addr >> HASH_FN_SHIFT) & HASH_FN_MASK;
 237 }
 238
 239 /*
 240  * Request exclusive access to a hash bucket for a given dma_debug_entry.
 241  */
 242 static struct hash_bucket *get_hash_bucket(struct dma_debug_entry *entry,
 243                                            unsigned long *flags)
 244         __acquires(&dma_entry_hash[idx].lock)
 245 {
 246         int idx = hash_fn(entry);
 247         unsigned long __flags;
 248
 249         spin_lock_irqsave(&dma_entry_hash[idx].lock, __flags);
 250         *flags = __flags;
 251         return &dma_entry_hash[idx];
 252 }
 253
 254 /*
 255  * Give up exclusive access to the hash bucket
 256  */
 257 static void put_hash_bucket(struct hash_bucket *bucket,
 258                             unsigned long *flags)
 259         __releases(&bucket->lock)
 260 {
 261         unsigned long __flags = *flags;
 262
 263         spin_unlock_irqrestore(&bucket->lock, __flags);
 264 }
 265
 266 static bool exact_match(struct dma_debug_entry *a, struct dma_debug_entry *b)
 267 {
 268         return ((a->dev_addr == b->dev_addr) &&
 269                 (a->dev == b->dev)) ? true : false;
 270 }
 271
 272 static bool containing_match(struct dma_debug_entry *a,
 273                              struct dma_debug_entry *b)
 274 {
 275         if (a->dev != b->dev)
 276                 return false;
 277
 278         if ((b->dev_addr <= a->dev_addr) &&
 279             ((b->dev_addr + b->size) >= (a->dev_addr + a->size)))
 280                 return true;
 281
 282         return false;
 283 }
 284
 285 /*
 286  * Search a given entry in the hash bucket list
 287  */
 288 static struct dma_debug_entry *__hash_bucket_find(struct hash_bucket *bucket,
 289                                                   struct dma_debug_entry *ref,
 290                                                   match_fn match)
 291 {
 292         struct dma_debug_entry *entry, *ret = NULL;
 293         int matches = 0, match_lvl, last_lvl = -1;
 294
 295         list_for_each_entry(entry, &bucket->list, list) {
 296                 if (!match(ref, entry))
 297                         continue;
 298
 299                 /*
 300                  * Some drivers map the same physical address multiple
 301                  * times. Without a hardware IOMMU this results in the
 302                  * same device addresses being put into the dma-debug
 303                  * hash multiple times too. This can result in false
 304                  * positives being reported. Therefore we implement a
 305                  * best-fit algorithm here which returns the entry from
 306                  * the hash which fits best to the reference value
 307                  * instead of the first-fit.
 308                  */
 309                 matches += 1;
 310                 match_lvl = 0;
 311                 entry->size         == ref->size         ? ++match_lvl : 0;
 312                 entry->type         == ref->type         ? ++match_lvl : 0;
 313                 entry->direction    == ref->direction    ? ++match_lvl : 0;
 314                 entry->sg_call_ents == ref->sg_call_ents ? ++match_lvl : 0;
 315
 316                 if (match_lvl == 4) {
 317                         /* perfect-fit - return the result */
 318                         return entry;
 319                 } else if (match_lvl > last_lvl) {
 320                         /*
 321                          * We found an entry that fits better then the
 322                          * previous one or it is the 1st match.
 323                          */
 324                         last_lvl = match_lvl;
 325                         ret      = entry;
 326                 }
 327         }
 328
 329         /*
 330          * If we have multiple matches but no perfect-fit, just return
 331          * NULL.
 332          */
 333         ret = (matches == 1) ? ret : NULL;
 334
 335         return ret;
 336 }
 337
 338 static struct dma_debug_entry *bucket_find_exact(struct hash_bucket *bucket,
 339                                                  struct dma_debug_entry *ref)
 340 {
 341         return __hash_bucket_find(bucket, ref, exact_match);
 342 }
 343
 344 static struct dma_debug_entry *bucket_find_contain(struct hash_bucket **bucket,
 345                                                    struct dma_debug_entry *ref,
 346                                                    unsigned long *flags)
 347 {
 348
 349         unsigned int max_range = dma_get_max_seg_size(ref->dev);
 350         struct dma_debug_entry *entry, index = *ref;
 351         unsigned int range = 0;
 352
 353         while (range <= max_range) {
 354                 entry = __hash_bucket_find(*bucket, ref, containing_match);
 355
 356                 if (entry)
 357                         return entry;
 358
 359                 /*
 360                  * Nothing found, go back a hash bucket
 361                  */
 362                 put_hash_bucket(*bucket, flags);
 363                 range          += (1 << HASH_FN_SHIFT);
 364                 index.dev_addr -= (1 << HASH_FN_SHIFT);
 365                 *bucket = get_hash_bucket(&index, flags);
 366         }
 367
 368         return NULL;
 369 }
 370
 371 /*
 372  * Add an entry to a hash bucket
 373  */
 374 static void hash_bucket_add(struct hash_bucket *bucket,
 375                             struct dma_debug_entry *entry)
 376 {
 377         list_add_tail(&entry->list, &bucket->list);
 378 }
 379
 380 /*
 381  * Remove entry from a hash bucket list
 382  */
 383 static void hash_bucket_del(struct dma_debug_entry *entry)
 384 {
 385         list_del(&entry->list);
 386 }
 387
 388 static unsigned long long phys_addr(struct dma_debug_entry *entry)
 389 {
 390         if (entry->type == dma_debug_resource)
 391                 return __pfn_to_phys(entry->pfn) + entry->offset;
 392
 393         return page_to_phys(pfn_to_page(entry->pfn)) + entry->offset;
 394 }
 395
 396 /*
 397  * Dump mapping entries for debugging purposes
 398  */
 399 void debug_dma_dump_mappings(struct device *dev)
 400 {
 401         int idx;
 402
 403         for (idx = 0; idx < HASH_SIZE; idx++) {
 404                 struct hash_bucket *bucket = &dma_entry_hash[idx];
 405                 struct dma_debug_entry *entry;
 406                 unsigned long flags;
 407
 408                 spin_lock_irqsave(&bucket->lock, flags);
 409
 410                 list_for_each_entry(entry, &bucket->list, list) {
 411                         if (!dev || dev == entry->dev) {
 412                                 dev_info(entry->dev,
 413                                          "%s idx %d P=%Lx N=%lx D=%Lx L=%Lx %s %s\n",
 414                                          type2name[entry->type], idx,
 415                                          phys_addr(entry), entry->pfn,
 416                                          entry->dev_addr, entry->size,
 417                                          dir2name[entry->direction],
 418                                          maperr2str[entry->map_err_type]);
 419                         }
 420                 }
 421
 422                 spin_unlock_irqrestore(&bucket->lock, flags);
 423                 cond_resched();
 424         }
 425 }
 426
 427 /*
 428  * For each mapping (initial cacheline in the case of
 429  * dma_alloc_coherent/dma_map_page, initial cacheline in each page of a
 430  * scatterlist, or the cacheline specified in dma_map_single) insert
 431  * into this tree using the cacheline as the key. At
 432  * dma_unmap_{single|sg|page} or dma_free_coherent delete the entry.  If
 433  * the entry already exists at insertion time add a tag as a reference
 434  * count for the overlapping mappings.  For now, the overlap tracking
 435  * just ensures that 'unmaps' balance 'maps' before marking the
 436  * cacheline idle, but we should also be flagging overlaps as an API
 437  * violation.
 438  *
 439  * Memory usage is mostly constrained by the maximum number of available
 440  * dma-debug entries in that we need a free dma_debug_entry before
 441  * inserting into the tree.  In the case of dma_map_page and
 442  * dma_alloc_coherent there is only one dma_debug_entry and one
 443  * dma_active_cacheline entry to track per event.  dma_map_sg(), on the
 444  * other hand, consumes a single dma_debug_entry, but inserts 'nents'
 445  * entries into the tree.
 446  *
 447  * At any time debug_dma_assert_idle() can be called to trigger a
 448  * warning if any cachelines in the given page are in the active set.
 449  */
 450 static RADIX_TREE(dma_active_cacheline, GFP_NOWAIT);
 451 static DEFINE_SPINLOCK(radix_lock);
 452 #define ACTIVE_CACHELINE_MAX_OVERLAP ((1 << RADIX_TREE_MAX_TAGS) - 1)
 453 #define CACHELINE_PER_PAGE_SHIFT (PAGE_SHIFT - L1_CACHE_SHIFT)
 454 #define CACHELINES_PER_PAGE (1 << CACHELINE_PER_PAGE_SHIFT)
 455
 456 static phys_addr_t to_cacheline_number(struct dma_debug_entry *entry)
 457 {
 458         return (entry->pfn << CACHELINE_PER_PAGE_SHIFT) +
 459                 (entry->offset >> L1_CACHE_SHIFT);
 460 }
 461
 462 static int active_cacheline_read_overlap(phys_addr_t cln)
 463 {
 464         int overlap = 0, i;
 465
 466         for (i = RADIX_TREE_MAX_TAGS - 1; i >= 0; i--)
 467                 if (radix_tree_tag_get(&dma_active_cacheline, cln, i))
 468                         overlap |= 1 << i;
 469         return overlap;
 470 }
 471
 472 static int active_cacheline_set_overlap(phys_addr_t cln, int overlap)
 473 {
 474         int i;
 475
 476         if (overlap > ACTIVE_CACHELINE_MAX_OVERLAP || overlap < 0)
 477                 return overlap;
 478
 479         for (i = RADIX_TREE_MAX_TAGS - 1; i >= 0; i--)
 480                 if (overlap & 1 << i)
 481                         radix_tree_tag_set(&dma_active_cacheline, cln, i);
 482                 else
 483                         radix_tree_tag_clear(&dma_active_cacheline, cln, i);
 484
 485         return overlap;
 486 }
 487
 488 static void active_cacheline_inc_overlap(phys_addr_t cln)
 489 {
 490         int overlap = active_cacheline_read_overlap(cln);
 491
 492         overlap = active_cacheline_set_overlap(cln, ++overlap);
 493
 494         /* If we overflowed the overlap counter then we're potentially
 495          * leaking dma-mappings.  Otherwise, if maps and unmaps are
 496          * balanced then this overflow may cause false negatives in
 497          * debug_dma_assert_idle() as the cacheline may be marked idle
 498          * prematurely.
 499          */
 500         WARN_ONCE(overlap > ACTIVE_CACHELINE_MAX_OVERLAP,
 501                   pr_fmt("exceeded %d overlapping mappings of cacheline %pa\n"),
 502                   ACTIVE_CACHELINE_MAX_OVERLAP, &cln);
 503 }
 504
 505 static int active_cacheline_dec_overlap(phys_addr_t cln)
 506 {
 507         int overlap = active_cacheline_read_overlap(cln);
 508
 509         return active_cacheline_set_overlap(cln, --overlap);
 510 }
 511
 512 static int active_cacheline_insert(struct dma_debug_entry *entry)
 513 {
 514         phys_addr_t cln = to_cacheline_number(entry);
 515         unsigned long flags;
 516         int rc;
 517
 518         /* If the device is not writing memory then we don't have any
 519          * concerns about the cpu consuming stale data.  This mitigates
 520          * legitimate usages of overlapping mappings.
 521          */
 522         if (entry->direction == DMA_TO_DEVICE)
 523                 return 0;
 524
 525         spin_lock_irqsave(&radix_lock, flags);
 526         rc = radix_tree_insert(&dma_active_cacheline, cln, entry);
 527         if (rc == -EEXIST)
 528                 active_cacheline_inc_overlap(cln);
 529         spin_unlock_irqrestore(&radix_lock, flags);
 530
 531         return rc;
 532 }
 533
 534 static void active_cacheline_remove(struct dma_debug_entry *entry)
 535 {
 536         phys_addr_t cln = to_cacheline_number(entry);
 537         unsigned long flags;
 538
 539         /* ...mirror the insert case */
 540         if (entry->direction == DMA_TO_DEVICE)
 541                 return;
 542
 543         spin_lock_irqsave(&radix_lock, flags);
 544         /* since we are counting overlaps the final put of the
 545          * cacheline will occur when the overlap count is 0.
 546          * active_cacheline_dec_overlap() returns -1 in that case
 547          */
 548         if (active_cacheline_dec_overlap(cln) < 0)
 549                 radix_tree_delete(&dma_active_cacheline, cln);
 550         spin_unlock_irqrestore(&radix_lock, flags);
 551 }
 552
 553 /**
 554  * debug_dma_assert_idle() - assert that a page is not undergoing dma
 555  * @page: page to lookup in the dma_active_cacheline tree
 556  *
 557  * Place a call to this routine in cases where the cpu touching the page
 558  * before the dma completes (page is dma_unmapped) will lead to data
 559  * corruption.
 560  */
 561 void debug_dma_assert_idle(struct page *page)
 562 {
 563         static struct dma_debug_entry *ents[CACHELINES_PER_PAGE];
 564         struct dma_debug_entry *entry = NULL;
 565         void **results = (void **) &ents;
 566         unsigned int nents, i;
 567         unsigned long flags;
 568         phys_addr_t cln;
 569
 570         if (dma_debug_disabled())
 571                 return;
 572
 573         if (!page)
 574                 return;
 575
 576         cln = (phys_addr_t) page_to_pfn(page) << CACHELINE_PER_PAGE_SHIFT;
 577         spin_lock_irqsave(&radix_lock, flags);
 578         nents = radix_tree_gang_lookup(&dma_active_cacheline, results, cln,
 579                                        CACHELINES_PER_PAGE);
 580         for (i = 0; i < nents; i++) {
 581                 phys_addr_t ent_cln = to_cacheline_number(ents[i]);
 582
 583                 if (ent_cln == cln) {
 584                         entry = ents[i];
 585                         break;
 586                 } else if (ent_cln >= cln + CACHELINES_PER_PAGE)
 587                         break;
 588         }
 589         spin_unlock_irqrestore(&radix_lock, flags);
 590
 591         if (!entry)
 592                 return;
 593
 594         cln = to_cacheline_number(entry);
 595         err_printk(entry->dev, entry,
 596                    "cpu touching an active dma mapped cacheline [cln=%pa]\n",
 597                    &cln);
 598 }
 599
 600 /*
 601  * Wrapper function for adding an entry to the hash.
 602  * This function takes care of locking itself.
 603  */
 604 static void add_dma_entry(struct dma_debug_entry *entry)
 605 {
 606         struct hash_bucket *bucket;
 607         unsigned long flags;
 608         int rc;
 609
 610         bucket = get_hash_bucket(entry, &flags);
 611         hash_bucket_add(bucket, entry);
 612         put_hash_bucket(bucket, &flags);
 613
 614         rc = active_cacheline_insert(entry);
 615         if (rc == -ENOMEM) {
 616                 pr_err("cacheline tracking ENOMEM, dma-debug disabled\n");
 617                 global_disable = true;
 618         }
 619
 620         /* TODO: report -EEXIST errors here as overlapping mappings are
 621          * not supported by the DMA API
 622          */
 623 }
 624
 625 static int dma_debug_create_entries(gfp_t gfp)
 626 {
 627         struct dma_debug_entry *entry;
 628         int i;
 629
 630         entry = (void *)get_zeroed_page(gfp);
 631         if (!entry)
 632                 return -ENOMEM;
 633
 634         for (i = 0; i < DMA_DEBUG_DYNAMIC_ENTRIES; i++)
 635                 list_add_tail(&entry[i].list, &free_entries);
 636
 637         num_free_entries += DMA_DEBUG_DYNAMIC_ENTRIES;
 638         nr_total_entries += DMA_DEBUG_DYNAMIC_ENTRIES;
 639
 640         return 0;
 641 }
 642
 643 static struct dma_debug_entry *__dma_entry_alloc(void)
 644 {
 645         struct dma_debug_entry *entry;
 646
 647         entry = list_entry(free_entries.next, struct dma_debug_entry, list);
 648         list_del(&entry->list);
 649         memset(entry, 0, sizeof(*entry));
 650
 651         num_free_entries -= 1;
 652         if (num_free_entries < min_free_entries)
 653                 min_free_entries = num_free_entries;
 654
 655         return entry;
 656 }
 657
 658 void __dma_entry_alloc_check_leak(void)
 659 {
 660         u32 tmp = nr_total_entries % nr_prealloc_entries;
 661
 662         /* Shout each time we tick over some multiple of the initial pool */
 663         if (tmp < DMA_DEBUG_DYNAMIC_ENTRIES) {
 664                 pr_info("dma_debug_entry pool grown to %u (%u00%%)\n",
 665                         nr_total_entries,
 666                         (nr_total_entries / nr_prealloc_entries));
 667         }
 668 }
 669
 670 /* struct dma_entry allocator
 671  *
 672  * The next two functions implement the allocator for
 673  * struct dma_debug_entries.
 674  */
 675 static struct dma_debug_entry *dma_entry_alloc(void)
 676 {
 677         struct dma_debug_entry *entry;
 678         unsigned long flags;
 679
 680         spin_lock_irqsave(&free_entries_lock, flags);
 681         if (num_free_entries == 0) {
 682                 if (dma_debug_create_entries(GFP_ATOMIC)) {
 683                         global_disable = true;
 684                         spin_unlock_irqrestore(&free_entries_lock, flags);
 685                         pr_err("debugging out of memory - disabling\n");
 686                         return NULL;
 687                 }
 688                 __dma_entry_alloc_check_leak();
 689         }
 690
 691         entry = __dma_entry_alloc();
 692
 693         spin_unlock_irqrestore(&free_entries_lock, flags);
 694
 695 #ifdef CONFIG_STACKTRACE
 696         entry->stack_len = stack_trace_save(entry->stack_entries,
 697                                             ARRAY_SIZE(entry->stack_entries),
 698                                             1);
 699 #endif
 700         return entry;
 701 }
 702
 703 static void dma_entry_free(struct dma_debug_entry *entry)
 704 {
 705         unsigned long flags;
 706
 707         active_cacheline_remove(entry);
 708
 709         /*
 710          * add to beginning of the list - this way the entries are
 711          * more likely cache hot when they are reallocated.
 712          */
 713         spin_lock_irqsave(&free_entries_lock, flags);
 714         list_add(&entry->list, &free_entries);
 715         num_free_entries += 1;
 716         spin_unlock_irqrestore(&free_entries_lock, flags);
 717 }
 718
 719 /*
 720  * DMA-API debugging init code
 721  *
 722  * The init code does two things:
 723  *   1. Initialize core data structures
 724  *   2. Preallocate a given number of dma_debug_entry structs
 725  */
 726
 727 static ssize_t filter_read(struct file *file, char __user *user_buf,
 728                            size_t count, loff_t *ppos)
 729 {
 730         char buf[NAME_MAX_LEN + 1];
 731         unsigned long flags;
 732         int len;
 733
 734         if (!current_driver_name[0])
 735                 return 0;
 736
 737         /*
 738          * We can't copy to userspace directly because current_driver_name can
 739          * only be read under the driver_name_lock with irqs disabled. So
 740          * create a temporary copy first.
 741          */
 742         read_lock_irqsave(&driver_name_lock, flags);
 743         len = scnprintf(buf, NAME_MAX_LEN + 1, "%s\n", current_driver_name);
 744         read_unlock_irqrestore(&driver_name_lock, flags);
 745
 746         return simple_read_from_buffer(user_buf, count, ppos, buf, len);
 747 }
 748
 749 static ssize_t filter_write(struct file *file, const char __user *userbuf,
 750                             size_t count, loff_t *ppos)
 751 {
 752         char buf[NAME_MAX_LEN];
 753         unsigned long flags;
 754         size_t len;
 755         int i;
 756
 757         /*
 758          * We can't copy from userspace directly. Access to
 759          * current_driver_name is protected with a write_lock with irqs
 760          * disabled. Since copy_from_user can fault and may sleep we
 761          * need to copy to temporary buffer first
 762          */
 763         len = min(count, (size_t)(NAME_MAX_LEN - 1));
 764         if (copy_from_user(buf, userbuf, len))
 765                 return -EFAULT;
 766
 767         buf[len] = 0;
 768
 769         write_lock_irqsave(&driver_name_lock, flags);
 770
 771         /*
 772          * Now handle the string we got from userspace very carefully.
 773          * The rules are:
 774          *         - only use the first token we got
 775          *         - token delimiter is everything looking like a space
 776          *           character (' ', '\n', '\t' ...)
 777          *
 778          */
 779         if (!isalnum(buf[0])) {
 780                 /*
 781                  * If the first character userspace gave us is not
 782                  * alphanumerical then assume the filter should be
 783                  * switched off.
 784                  */
 785                 if (current_driver_name[0])
 786                         pr_info("switching off dma-debug driver filter\n");
 787                 current_driver_name[0] = 0;
 788                 current_driver = NULL;
 789                 goto out_unlock;
 790         }
 791
 792         /*
 793          * Now parse out the first token and use it as the name for the
 794          * driver to filter for.
 795          */
 796         for (i = 0; i < NAME_MAX_LEN - 1; ++i) {
 797                 current_driver_name[i] = buf[i];
 798                 if (isspace(buf[i]) || buf[i] == ' ' || buf[i] == 0)
 799                         break;
 800         }
 801         current_driver_name[i] = 0;
 802         current_driver = NULL;
 803
 804         pr_info("enable driver filter for driver [%s]\n",
 805                 current_driver_name);
 806
 807 out_unlock:
 808         write_unlock_irqrestore(&driver_name_lock, flags);
 809
 810         return count;
 811 }
 812
 813 static const struct file_operations filter_fops = {
 814         .read  = filter_read,
 815         .write = filter_write,
 816         .llseek = default_llseek,
 817 };
 818
 819 static int dump_show(struct seq_file *seq, void *v)
 820 {
 821         int idx;
 822
 823         for (idx = 0; idx < HASH_SIZE; idx++) {
 824                 struct hash_bucket *bucket = &dma_entry_hash[idx];
 825                 struct dma_debug_entry *entry;
 826                 unsigned long flags;
 827
 828                 spin_lock_irqsave(&bucket->lock, flags);
 829                 list_for_each_entry(entry, &bucket->list, list) {
 830                         seq_printf(seq,
 831                                    "%s %s %s idx %d P=%llx N=%lx D=%llx L=%llx %s %s\n",
 832                                    dev_name(entry->dev),
 833                                    dev_driver_string(entry->dev),
 834                                    type2name[entry->type], idx,
 835                                    phys_addr(entry), entry->pfn,
 836                                    entry->dev_addr, entry->size,
 837                                    dir2name[entry->direction],
 838                                    maperr2str[entry->map_err_type]);
 839                 }
 840                 spin_unlock_irqrestore(&bucket->lock, flags);
 841         }
 842         return 0;
 843 }
 844 DEFINE_SHOW_ATTRIBUTE(dump);
 845
 846 static void dma_debug_fs_init(void)
 847 {
 848         struct dentry *dentry = debugfs_create_dir("dma-api", NULL);
 849
 850         debugfs_create_bool("disabled", 0444, dentry, &global_disable);
 851         debugfs_create_u32("error_count", 0444, dentry, &error_count);
 852         debugfs_create_u32("all_errors", 0644, dentry, &show_all_errors);
 853         debugfs_create_u32("num_errors", 0644, dentry, &show_num_errors);
 854         debugfs_create_u32("num_free_entries", 0444, dentry, &num_free_entries);
 855         debugfs_create_u32("min_free_entries", 0444, dentry, &min_free_entries);
 856         debugfs_create_u32("nr_total_entries", 0444, dentry, &nr_total_entries);
 857         debugfs_create_file("driver_filter", 0644, dentry, NULL, &filter_fops);
 858         debugfs_create_file("dump", 0444, dentry, NULL, &dump_fops);
 859 }
 860
 861 static int device_dma_allocations(struct device *dev, struct dma_debug_entry **out_entry)
 862 {
 863         struct dma_debug_entry *entry;
 864         unsigned long flags;
 865         int count = 0, i;
 866
 867         for (i = 0; i < HASH_SIZE; ++i) {
 868                 spin_lock_irqsave(&dma_entry_hash[i].lock, flags);
 869                 list_for_each_entry(entry, &dma_entry_hash[i].list, list) {
 870                         if (entry->dev == dev) {
 871                                 count += 1;
 872                                 *out_entry = entry;
 873                         }
 874                 }
 875                 spin_unlock_irqrestore(&dma_entry_hash[i].lock, flags);
 876         }
 877
 878         return count;
 879 }
 880
 881 static int dma_debug_device_change(struct notifier_block *nb, unsigned long action, void *data)
 882 {
 883         struct device *dev = data;
 884         struct dma_debug_entry *uninitialized_var(entry);
 885         int count;
 886
 887         if (dma_debug_disabled())
 888                 return 0;
 889
 890         switch (action) {
 891         case BUS_NOTIFY_UNBOUND_DRIVER:
 892                 count = device_dma_allocations(dev, &entry);
 893                 if (count == 0)
 894                         break;
 895                 err_printk(dev, entry, "device driver has pending "
 896                                 "DMA allocations while released from device "
 897                                 "[count=%d]\n"
 898                                 "One of leaked entries details: "
 899                                 "[device address=0x%016llx] [size=%llu bytes] "
 900                                 "[mapped with %s] [mapped as %s]\n",
 901                         count, entry->dev_addr, entry->size,
 902                         dir2name[entry->direction], type2name[entry->type]);
 903                 break;
 904         default:
 905                 break;
 906         }
 907
 908         return 0;
 909 }
 910
 911 void dma_debug_add_bus(struct bus_type *bus)
 912 {
 913         struct notifier_block *nb;
 914
 915         if (dma_debug_disabled())
 916                 return;
 917
 918         nb = kzalloc(sizeof(struct notifier_block), GFP_KERNEL);
 919         if (nb == NULL) {
 920                 pr_err("dma_debug_add_bus: out of memory\n");
 921                 return;
 922         }
 923
 924         nb->notifier_call = dma_debug_device_change;
 925
 926         bus_register_notifier(bus, nb);
 927 }
 928
 929 static int dma_debug_init(void)
 930 {
 931         int i, nr_pages;
 932
 933         /* Do not use dma_debug_initialized here, since we really want to be
 934          * called to set dma_debug_initialized
 935          */
 936         if (global_disable)
 937                 return 0;
 938
 939         for (i = 0; i < HASH_SIZE; ++i) {
 940                 INIT_LIST_HEAD(&dma_entry_hash[i].list);
 941                 spin_lock_init(&dma_entry_hash[i].lock);
 942         }
 943
 944         dma_debug_fs_init();
 945
 946         nr_pages = DIV_ROUND_UP(nr_prealloc_entries, DMA_DEBUG_DYNAMIC_ENTRIES);
 947         for (i = 0; i < nr_pages; ++i)
 948                 dma_debug_create_entries(GFP_KERNEL);
 949         if (num_free_entries >= nr_prealloc_entries) {
 950                 pr_info("preallocated %d debug entries\n", nr_total_entries);
 951         } else if (num_free_entries > 0) {
 952                 pr_warn("%d debug entries requested but only %d allocated\n",
 953                         nr_prealloc_entries, nr_total_entries);
 954         } else {
 955                 pr_err("debugging out of memory error - disabled\n");
 956                 global_disable = true;
 957
 958                 return 0;
 959         }
 960         min_free_entries = num_free_entries;
 961
 962         dma_debug_initialized = true;
 963
 964         pr_info("debugging enabled by kernel config\n");
 965         return 0;
 966 }
 967 core_initcall(dma_debug_init);
 968
 969 static __init int dma_debug_cmdline(char *str)
 970 {
 971         if (!str)
 972                 return -EINVAL;
 973
 974         if (strncmp(str, "off", 3) == 0) {
 975                 pr_info("debugging disabled on kernel command line\n");
 976                 global_disable = true;
 977         }
 978
 979         return 0;
 980 }
 981
 982 static __init int dma_debug_entries_cmdline(char *str)
 983 {
 984         if (!str)
 985                 return -EINVAL;
 986         if (!get_option(&str, &nr_prealloc_entries))
 987                 nr_prealloc_entries = PREALLOC_DMA_DEBUG_ENTRIES;
 988         return 0;
 989 }
 990
 991 __setup("dma_debug=", dma_debug_cmdline);
 992 __setup("dma_debug_entries=", dma_debug_entries_cmdline);
 993
 994 static void check_unmap(struct dma_debug_entry *ref)
 995 {
 996         struct dma_debug_entry *entry;
 997         struct hash_bucket *bucket;
 998         unsigned long flags;
 999
1000         bucket = get_hash_bucket(ref, &flags);
1001         entry = bucket_find_exact(bucket, ref);
1002
1003         if (!entry) {
1004                 /* must drop lock before calling dma_mapping_error */
1005                 put_hash_bucket(bucket, &flags);
1006
1007                 if (dma_mapping_error(ref->dev, ref->dev_addr)) {
1008                         err_printk(ref->dev, NULL,
1009                                    "device driver tries to free an "
1010                                    "invalid DMA memory address\n");
1011                 } else {
1012                         err_printk(ref->dev, NULL,
1013                                    "device driver tries to free DMA "
1014                                    "memory it has not allocated [device "
1015                                    "address=0x%016llx] [size=%llu bytes]\n",
1016                                    ref->dev_addr, ref->size);
1017                 }
1018                 return;
1019         }
1020
1021         if (ref->size != entry->size) {
1022                 err_printk(ref->dev, entry, "device driver frees "
1023                            "DMA memory with different size "
1024                            "[device address=0x%016llx] [map size=%llu bytes] "
1025                            "[unmap size=%llu bytes]\n",
1026                            ref->dev_addr, entry->size, ref->size);
1027         }
1028
1029         if (ref->type != entry->type) {
1030                 err_printk(ref->dev, entry, "device driver frees "
1031                            "DMA memory with wrong function "
1032                            "[device address=0x%016llx] [size=%llu bytes] "
1033                            "[mapped as %s] [unmapped as %s]\n",
1034                            ref->dev_addr, ref->size,
1035                            type2name[entry->type], type2name[ref->type]);
1036         } else if ((entry->type == dma_debug_coherent) &&
1037                    (phys_addr(ref) != phys_addr(entry))) {
1038                 err_printk(ref->dev, entry, "device driver frees "
1039                            "DMA memory with different CPU address "
1040                            "[device address=0x%016llx] [size=%llu bytes] "
1041                            "[cpu alloc address=0x%016llx] "
1042                            "[cpu free address=0x%016llx]",
1043                            ref->dev_addr, ref->size,
1044                            phys_addr(entry),
1045                            phys_addr(ref));
1046         }
1047
1048         if (ref->sg_call_ents && ref->type == dma_debug_sg &&
1049             ref->sg_call_ents != entry->sg_call_ents) {
1050                 err_printk(ref->dev, entry, "device driver frees "
1051                            "DMA sg list with different entry count "
1052                            "[map count=%d] [unmap count=%d]\n",
1053                            entry->sg_call_ents, ref->sg_call_ents);
1054         }
1055
1056         /*
1057          * This may be no bug in reality - but most implementations of the
1058          * DMA API don't handle this properly, so check for it here
1059          */
1060         if (ref->direction != entry->direction) {
1061                 err_printk(ref->dev, entry, "device driver frees "
1062                            "DMA memory with different direction "
1063                            "[device address=0x%016llx] [size=%llu bytes] "
1064                            "[mapped with %s] [unmapped with %s]\n",
1065                            ref->dev_addr, ref->size,
1066                            dir2name[entry->direction],
1067                            dir2name[ref->direction]);
1068         }
1069
1070         /*
1071          * Drivers should use dma_mapping_error() to check the returned
1072          * addresses of dma_map_single() and dma_map_page().
1073          * If not, print this warning message. See Documentation/DMA-API.txt.
1074          */
1075         if (entry->map_err_type == MAP_ERR_NOT_CHECKED) {
1076                 err_printk(ref->dev, entry,
1077                            "device driver failed to check map error"
1078                            "[device address=0x%016llx] [size=%llu bytes] "
1079                            "[mapped as %s]",
1080                            ref->dev_addr, ref->size,
1081                            type2name[entry->type]);
1082         }
1083
1084         hash_bucket_del(entry);
1085         dma_entry_free(entry);
1086
1087         put_hash_bucket(bucket, &flags);
1088 }
1089
1090 static void check_for_stack(struct device *dev,
1091                             struct page *page, size_t offset)
1092 {
1093         void *addr;
1094         struct vm_struct *stack_vm_area = task_stack_vm_area(current);
1095
1096         if (!stack_vm_area) {
1097                 /* Stack is direct-mapped. */
1098                 if (PageHighMem(page))
1099                         return;
1100                 addr = page_address(page) + offset;
1101                 if (object_is_on_stack(addr))
1102                         err_printk(dev, NULL, "device driver maps memory from stack [addr=%p]\n", addr);
1103         } else {
1104                 /* Stack is vmalloced. */
1105                 int i;
1106
1107                 for (i = 0; i < stack_vm_area->nr_pages; i++) {
1108                         if (page != stack_vm_area->pages[i])
1109                                 continue;
1110
1111                         addr = (u8 *)current->stack + i * PAGE_SIZE + offset;
1112                         err_printk(dev, NULL, "device driver maps memory from stack [probable addr=%p]\n", addr);
1113                         break;
1114                 }
1115         }
1116 }
1117
1118 static inline bool overlap(void *addr, unsigned long len, void *start, void *end)
1119 {
1120         unsigned long a1 = (unsigned long)addr;
1121         unsigned long b1 = a1 + len;
1122         unsigned long a2 = (unsigned long)start;
1123         unsigned long b2 = (unsigned long)end;
1124
1125         return !(b1 <= a2 || a1 >= b2);
1126 }
1127
1128 static void check_for_illegal_area(struct device *dev, void *addr, unsigned long len)
1129 {
1130         if (overlap(addr, len, _stext, _etext) ||
1131             overlap(addr, len, __start_rodata, __end_rodata))
1132                 err_printk(dev, NULL, "device driver maps memory from kernel text or rodata [addr=%p] [len=%lu]\n", addr, len);
1133 }
1134
1135 static void check_sync(struct device *dev,
1136                        struct dma_debug_entry *ref,
1137                        bool to_cpu)
1138 {
1139         struct dma_debug_entry *entry;
1140         struct hash_bucket *bucket;
1141         unsigned long flags;
1142
1143         bucket = get_hash_bucket(ref, &flags);
1144
1145         entry = bucket_find_contain(&bucket, ref, &flags);
1146
1147         if (!entry) {
1148                 err_printk(dev, NULL, "device driver tries "
1149                                 "to sync DMA memory it has not allocated "
1150                                 "[device address=0x%016llx] [size=%llu bytes]\n",
1151                                 (unsigned long long)ref->dev_addr, ref->size);
1152                 goto out;
1153         }
1154
1155         if (ref->size > entry->size) {
1156                 err_printk(dev, entry, "device driver syncs"
1157                                 " DMA memory outside allocated range "
1158                                 "[device address=0x%016llx] "
1159                                 "[allocation size=%llu bytes] "
1160                                 "[sync offset+size=%llu]\n",
1161                                 entry->dev_addr, entry->size,
1162                                 ref->size);
1163         }
1164
1165         if (entry->direction == DMA_BIDIRECTIONAL)
1166                 goto out;
1167
1168         if (ref->direction != entry->direction) {
1169                 err_printk(dev, entry, "device driver syncs "
1170                                 "DMA memory with different direction "
1171                                 "[device address=0x%016llx] [size=%llu bytes] "
1172                                 "[mapped with %s] [synced with %s]\n",
1173                                 (unsigned long long)ref->dev_addr, entry->size,
1174                                 dir2name[entry->direction],
1175                                 dir2name[ref->direction]);
1176         }
1177
1178         if (to_cpu && !(entry->direction == DMA_FROM_DEVICE) &&
1179                       !(ref->direction == DMA_TO_DEVICE))
1180                 err_printk(dev, entry, "device driver syncs "
1181                                 "device read-only DMA memory for cpu "
1182                                 "[device address=0x%016llx] [size=%llu bytes] "
1183                                 "[mapped with %s] [synced with %s]\n",
1184                                 (unsigned long long)ref->dev_addr, entry->size,
1185                                 dir2name[entry->direction],
1186                                 dir2name[ref->direction]);
1187
1188         if (!to_cpu && !(entry->direction == DMA_TO_DEVICE) &&
1189                        !(ref->direction == DMA_FROM_DEVICE))
1190                 err_printk(dev, entry, "device driver syncs "
1191                                 "device write-only DMA memory to device "
1192                                 "[device address=0x%016llx] [size=%llu bytes] "
1193                                 "[mapped with %s] [synced with %s]\n",
1194                                 (unsigned long long)ref->dev_addr, entry->size,
1195                                 dir2name[entry->direction],
1196                                 dir2name[ref->direction]);
1197
1198         if (ref->sg_call_ents && ref->type == dma_debug_sg &&
1199             ref->sg_call_ents != entry->sg_call_ents) {
1200                 err_printk(ref->dev, entry, "device driver syncs "
1201                            "DMA sg list with different entry count "
1202                            "[map count=%d] [sync count=%d]\n",
1203                            entry->sg_call_ents, ref->sg_call_ents);
1204         }
1205
1206 out:
1207         put_hash_bucket(bucket, &flags);
1208 }
1209
1210 static void check_sg_segment(struct device *dev, struct scatterlist *sg)
1211 {
1212 #ifdef CONFIG_DMA_API_DEBUG_SG
1213         unsigned int max_seg = dma_get_max_seg_size(dev);
1214         u64 start, end, boundary = dma_get_seg_boundary(dev);
1215
1216         /*
1217          * Either the driver forgot to set dma_parms appropriately, or
1218          * whoever generated the list forgot to check them.
1219          */
1220         if (sg->length > max_seg)
1221                 err_printk(dev, NULL, "mapping sg segment longer than device claims to support [len=%u] [max=%u]\n",
1222                            sg->length, max_seg);
1223         /*
1224          * In some cases this could potentially be the DMA API
1225          * implementation's fault, but it would usually imply that
1226          * the scatterlist was built inappropriately to begin with.
1227          */
1228         start = sg_dma_address(sg);
1229         end = start + sg_dma_len(sg) - 1;
1230         if ((start ^ end) & ~boundary)
1231                 err_printk(dev, NULL, "mapping sg segment across boundary [start=0x%016llx] [end=0x%016llx] [boundary=0x%016llx]\n",
1232                            start, end, boundary);
1233 #endif
1234 }
1235
1236 void debug_dma_map_single(struct device *dev, const void *addr,
1237                             unsigned long len)
1238 {
1239         if (unlikely(dma_debug_disabled()))
1240                 return;
1241
1242         if (!virt_addr_valid(addr))
1243                 err_printk(dev, NULL, "device driver maps memory from invalid area [addr=%p] [len=%lu]\n",
1244                            addr, len);
1245
1246         if (is_vmalloc_addr(addr))
1247                 err_printk(dev, NULL, "device driver maps memory from vmalloc area [addr=%p] [len=%lu]\n",
1248                            addr, len);
1249 }
1250 EXPORT_SYMBOL(debug_dma_map_single);
1251
1252 void debug_dma_map_page(struct device *dev, struct page *page, size_t offset,
1253                         size_t size, int direction, dma_addr_t dma_addr)
1254 {
1255         struct dma_debug_entry *entry;
1256
1257         if (unlikely(dma_debug_disabled()))
1258                 return;
1259
1260         if (dma_mapping_error(dev, dma_addr))
1261                 return;
1262
1263         entry = dma_entry_alloc();
1264         if (!entry)
1265                 return;
1266
1267         entry->dev       = dev;
1268         entry->type      = dma_debug_single;
1269         entry->pfn       = page_to_pfn(page);
1270         entry->offset    = offset,
1271         entry->dev_addr  = dma_addr;
1272         entry->size      = size;
1273         entry->direction = direction;
1274         entry->map_err_type = MAP_ERR_NOT_CHECKED;
1275
1276         check_for_stack(dev, page, offset);
1277
1278         if (!PageHighMem(page)) {
1279                 void *addr = page_address(page) + offset;
1280
1281                 check_for_illegal_area(dev, addr, size);
1282         }
1283
1284         add_dma_entry(entry);
1285 }
1286 EXPORT_SYMBOL(debug_dma_map_page);
1287
1288 void debug_dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
1289 {
1290         struct dma_debug_entry ref;
1291         struct dma_debug_entry *entry;
1292         struct hash_bucket *bucket;
1293         unsigned long flags;
1294
1295         if (unlikely(dma_debug_disabled()))
1296                 return;
1297
1298         ref.dev = dev;
1299         ref.dev_addr = dma_addr;
1300         bucket = get_hash_bucket(&ref, &flags);
1301
1302         list_for_each_entry(entry, &bucket->list, list) {
1303                 if (!exact_match(&ref, entry))
1304                         continue;
1305
1306                 /*
1307                  * The same physical address can be mapped multiple
1308                  * times. Without a hardware IOMMU this results in the
1309                  * same device addresses being put into the dma-debug
1310                  * hash multiple times too. This can result in false
1311                  * positives being reported. Therefore we implement a
1312                  * best-fit algorithm here which updates the first entry
1313                  * from the hash which fits the reference value and is
1314                  * not currently listed as being checked.
1315                  */
1316                 if (entry->map_err_type == MAP_ERR_NOT_CHECKED) {
1317                         entry->map_err_type = MAP_ERR_CHECKED;
1318                         break;
1319                 }
1320         }
1321
1322         put_hash_bucket(bucket, &flags);
1323 }
1324 EXPORT_SYMBOL(debug_dma_mapping_error);
1325
1326 void debug_dma_unmap_page(struct device *dev, dma_addr_t addr,
1327                           size_t size, int direction)
1328 {
1329         struct dma_debug_entry ref = {
1330                 .type           = dma_debug_single,
1331                 .dev            = dev,
1332                 .dev_addr       = addr,
1333                 .size           = size,
1334                 .direction      = direction,
1335         };
1336
1337         if (unlikely(dma_debug_disabled()))
1338                 return;
1339         check_unmap(&ref);
1340 }
1341 EXPORT_SYMBOL(debug_dma_unmap_page);
1342
1343 void debug_dma_map_sg(struct device *dev, struct scatterlist *sg,
1344                       int nents, int mapped_ents, int direction)
1345 {
1346         struct dma_debug_entry *entry;
1347         struct scatterlist *s;
1348         int i;
1349
1350         if (unlikely(dma_debug_disabled()))
1351                 return;
1352
1353         for_each_sg(sg, s, mapped_ents, i) {
1354                 entry = dma_entry_alloc();
1355                 if (!entry)
1356                         return;
1357
1358                 entry->type           = dma_debug_sg;
1359                 entry->dev            = dev;
1360                 entry->pfn            = page_to_pfn(sg_page(s));
1361                 entry->offset         = s->offset,
1362                 entry->size           = sg_dma_len(s);
1363                 entry->dev_addr       = sg_dma_address(s);
1364                 entry->direction      = direction;
1365                 entry->sg_call_ents   = nents;
1366                 entry->sg_mapped_ents = mapped_ents;
1367
1368                 check_for_stack(dev, sg_page(s), s->offset);
1369
1370                 if (!PageHighMem(sg_page(s))) {
1371                         check_for_illegal_area(dev, sg_virt(s), sg_dma_len(s));
1372                 }
1373
1374                 check_sg_segment(dev, s);
1375
1376                 add_dma_entry(entry);
1377         }
1378 }
1379 EXPORT_SYMBOL(debug_dma_map_sg);
1380
1381 static int get_nr_mapped_entries(struct device *dev,
1382                                  struct dma_debug_entry *ref)
1383 {
1384         struct dma_debug_entry *entry;
1385         struct hash_bucket *bucket;
1386         unsigned long flags;
1387         int mapped_ents;
1388
1389         bucket       = get_hash_bucket(ref, &flags);
1390         entry        = bucket_find_exact(bucket, ref);
1391         mapped_ents  = 0;
1392
1393         if (entry)
1394                 mapped_ents = entry->sg_mapped_ents;
1395         put_hash_bucket(bucket, &flags);
1396
1397         return mapped_ents;
1398 }
1399
1400 void debug_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
1401                         int nelems, int dir)
1402 {
1403         struct scatterlist *s;
1404         int mapped_ents = 0, i;
1405
1406         if (unlikely(dma_debug_disabled()))
1407                 return;
1408
1409         for_each_sg(sglist, s, nelems, i) {
1410
1411                 struct dma_debug_entry ref = {
1412                         .type           = dma_debug_sg,
1413                         .dev            = dev,
1414                         .pfn            = page_to_pfn(sg_page(s)),
1415                         .offset         = s->offset,
1416                         .dev_addr       = sg_dma_address(s),
1417                         .size           = sg_dma_len(s),
1418                         .direction      = dir,
1419                         .sg_call_ents   = nelems,
1420                 };
1421
1422                 if (mapped_ents && i >= mapped_ents)
1423                         break;
1424
1425                 if (!i)
1426                         mapped_ents = get_nr_mapped_entries(dev, &ref);
1427
1428                 check_unmap(&ref);
1429         }
1430 }
1431 EXPORT_SYMBOL(debug_dma_unmap_sg);
1432
1433 void debug_dma_alloc_coherent(struct device *dev, size_t size,
1434                               dma_addr_t dma_addr, void *virt)
1435 {
1436         struct dma_debug_entry *entry;
1437
1438         if (unlikely(dma_debug_disabled()))
1439                 return;
1440
1441         if (unlikely(virt == NULL))
1442                 return;
1443
1444         /* handle vmalloc and linear addresses */
1445         if (!is_vmalloc_addr(virt) && !virt_addr_valid(virt))
1446                 return;
1447
1448         entry = dma_entry_alloc();
1449         if (!entry)
1450                 return;
1451
1452         entry->type      = dma_debug_coherent;
1453         entry->dev       = dev;
1454         entry->offset    = offset_in_page(virt);
1455         entry->size      = size;
1456         entry->dev_addr  = dma_addr;
1457         entry->direction = DMA_BIDIRECTIONAL;
1458
1459         if (is_vmalloc_addr(virt))
1460                 entry->pfn = vmalloc_to_pfn(virt);
1461         else
1462                 entry->pfn = page_to_pfn(virt_to_page(virt));
1463
1464         add_dma_entry(entry);
1465 }
1466
1467 void debug_dma_free_coherent(struct device *dev, size_t size,
1468                          void *virt, dma_addr_t addr)
1469 {
1470         struct dma_debug_entry ref = {
1471                 .type           = dma_debug_coherent,
1472                 .dev            = dev,
1473                 .offset         = offset_in_page(virt),
1474                 .dev_addr       = addr,
1475                 .size           = size,
1476                 .direction      = DMA_BIDIRECTIONAL,
1477         };
1478
1479         /* handle vmalloc and linear addresses */
1480         if (!is_vmalloc_addr(virt) && !virt_addr_valid(virt))
1481                 return;
1482
1483         if (is_vmalloc_addr(virt))
1484                 ref.pfn = vmalloc_to_pfn(virt);
1485         else
1486                 ref.pfn = page_to_pfn(virt_to_page(virt));
1487
1488         if (unlikely(dma_debug_disabled()))
1489                 return;
1490
1491         check_unmap(&ref);
1492 }
1493
1494 void debug_dma_map_resource(struct device *dev, phys_addr_t addr, size_t size,
1495                             int direction, dma_addr_t dma_addr)
1496 {
1497         struct dma_debug_entry *entry;
1498
1499         if (unlikely(dma_debug_disabled()))
1500                 return;
1501
1502         entry = dma_entry_alloc();
1503         if (!entry)
1504                 return;
1505
1506         entry->type             = dma_debug_resource;
1507         entry->dev              = dev;
1508         entry->pfn              = PHYS_PFN(addr);
1509         entry->offset           = offset_in_page(addr);
1510         entry->size             = size;
1511         entry->dev_addr         = dma_addr;
1512         entry->direction        = direction;
1513         entry->map_err_type     = MAP_ERR_NOT_CHECKED;
1514
1515         add_dma_entry(entry);
1516 }
1517 EXPORT_SYMBOL(debug_dma_map_resource);
1518
1519 void debug_dma_unmap_resource(struct device *dev, dma_addr_t dma_addr,
1520                               size_t size, int direction)
1521 {
1522         struct dma_debug_entry ref = {
1523                 .type           = dma_debug_resource,
1524                 .dev            = dev,
1525                 .dev_addr       = dma_addr,
1526                 .size           = size,
1527                 .direction      = direction,
1528         };
1529
1530         if (unlikely(dma_debug_disabled()))
1531                 return;
1532
1533         check_unmap(&ref);
1534 }
1535 EXPORT_SYMBOL(debug_dma_unmap_resource);
1536
1537 void debug_dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_handle,
1538                                    size_t size, 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         = 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_for_cpu);
1555
1556 void debug_dma_sync_single_for_device(struct device *dev,
1557                                       dma_addr_t dma_handle, size_t size,
1558                                       int direction)
1559 {
1560         struct dma_debug_entry ref;
1561
1562         if (unlikely(dma_debug_disabled()))
1563                 return;
1564
1565         ref.type         = dma_debug_single;
1566         ref.dev          = dev;
1567         ref.dev_addr     = dma_handle;
1568         ref.size         = size;
1569         ref.direction    = direction;
1570         ref.sg_call_ents = 0;
1571
1572         check_sync(dev, &ref, false);
1573 }
1574 EXPORT_SYMBOL(debug_dma_sync_single_for_device);
1575
1576 void debug_dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
1577                                int nelems, int direction)
1578 {
1579         struct scatterlist *s;
1580         int mapped_ents = 0, i;
1581
1582         if (unlikely(dma_debug_disabled()))
1583                 return;
1584
1585         for_each_sg(sg, s, nelems, i) {
1586
1587                 struct dma_debug_entry ref = {
1588                         .type           = dma_debug_sg,
1589                         .dev            = dev,
1590                         .pfn            = page_to_pfn(sg_page(s)),
1591                         .offset         = s->offset,
1592                         .dev_addr       = sg_dma_address(s),
1593                         .size           = sg_dma_len(s),
1594                         .direction      = direction,
1595                         .sg_call_ents   = nelems,
1596                 };
1597
1598                 if (!i)
1599                         mapped_ents = get_nr_mapped_entries(dev, &ref);
1600
1601                 if (i >= mapped_ents)
1602                         break;
1603
1604                 check_sync(dev, &ref, true);
1605         }
1606 }
1607 EXPORT_SYMBOL(debug_dma_sync_sg_for_cpu);
1608
1609 void debug_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
1610                                   int nelems, int direction)
1611 {
1612         struct scatterlist *s;
1613         int mapped_ents = 0, i;
1614
1615         if (unlikely(dma_debug_disabled()))
1616                 return;
1617
1618         for_each_sg(sg, s, nelems, i) {
1619
1620                 struct dma_debug_entry ref = {
1621                         .type           = dma_debug_sg,
1622                         .dev            = dev,
1623                         .pfn            = page_to_pfn(sg_page(s)),
1624                         .offset         = s->offset,
1625                         .dev_addr       = sg_dma_address(s),
1626                         .size           = sg_dma_len(s),
1627                         .direction      = direction,
1628                         .sg_call_ents   = nelems,
1629                 };
1630                 if (!i)
1631                         mapped_ents = get_nr_mapped_entries(dev, &ref);
1632
1633                 if (i >= mapped_ents)
1634                         break;
1635
1636                 check_sync(dev, &ref, false);
1637         }
1638 }
1639 EXPORT_SYMBOL(debug_dma_sync_sg_for_device);
1640
1641 static int __init dma_debug_driver_setup(char *str)
1642 {
1643         int i;
1644
1645         for (i = 0; i < NAME_MAX_LEN - 1; ++i, ++str) {
1646                 current_driver_name[i] = *str;
1647                 if (*str == 0)
1648                         break;
1649         }
1650
1651         if (current_driver_name[0])
1652                 pr_info("enable driver filter for driver [%s]\n",
1653                         current_driver_name);
1654
1655
1656         return 1;
1657 }
1658 __setup("dma_debug_driver=", dma_debug_driver_setup);