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[] = {
 141         [dma_debug_single] = "single",
 142         [dma_debug_sg] = "scather-gather",
 143         [dma_debug_coherent] = "coherent",
 144         [dma_debug_resource] = "resource",
 145 };
 146
 147 static const char *dir2name[] = {
 148         [DMA_BIDIRECTIONAL]     = "DMA_BIDIRECTIONAL",
 149         [DMA_TO_DEVICE]         = "DMA_TO_DEVICE",
 150         [DMA_FROM_DEVICE]       = "DMA_FROM_DEVICE",
 151         [DMA_NONE]              = "DMA_NONE",
 152 };
 153
 154 /*
 155  * The access to some variables in this macro is racy. We can't use atomic_t
 156  * here because all these variables are exported to debugfs. Some of them even
 157  * writeable. This is also the reason why a lock won't help much. But anyway,
 158  * the races are no big deal. Here is why:
 159  *
 160  *   error_count: the addition is racy, but the worst thing that can happen is
 161  *                that we don't count some errors
 162  *   show_num_errors: the subtraction is racy. Also no big deal because in
 163  *                    worst case this will result in one warning more in the
 164  *                    system log than the user configured. This variable is
 165  *                    writeable via debugfs.
 166  */
 167 static inline void dump_entry_trace(struct dma_debug_entry *entry)
 168 {
 169 #ifdef CONFIG_STACKTRACE
 170         if (entry) {
 171                 pr_warn("Mapped at:\n");
 172                 stack_trace_print(entry->stack_entries, entry->stack_len, 0);
 173         }
 174 #endif
 175 }
 176
 177 static bool driver_filter(struct device *dev)
 178 {
 179         struct device_driver *drv;
 180         unsigned long flags;
 181         bool ret;
 182
 183         /* driver filter off */
 184         if (likely(!current_driver_name[0]))
 185                 return true;
 186
 187         /* driver filter on and initialized */
 188         if (current_driver && dev && dev->driver == current_driver)
 189                 return true;
 190
 191         /* driver filter on, but we can't filter on a NULL device... */
 192         if (!dev)
 193                 return false;
 194
 195         if (current_driver || !current_driver_name[0])
 196                 return false;
 197
 198         /* driver filter on but not yet initialized */
 199         drv = dev->driver;
 200         if (!drv)
 201                 return false;
 202
 203         /* lock to protect against change of current_driver_name */
 204         read_lock_irqsave(&driver_name_lock, flags);
 205
 206         ret = false;
 207         if (drv->name &&
 208             strncmp(current_driver_name, drv->name, NAME_MAX_LEN - 1) == 0) {
 209                 current_driver = drv;
 210                 ret = true;
 211         }
 212
 213         read_unlock_irqrestore(&driver_name_lock, flags);
 214
 215         return ret;
 216 }
 217
 218 #define err_printk(dev, entry, format, arg...) do {                     \
 219                 error_count += 1;                                       \
 220                 if (driver_filter(dev) &&                               \
 221                     (show_all_errors || show_num_errors > 0)) {         \
 222                         WARN(1, pr_fmt("%s %s: ") format,               \
 223                              dev ? dev_driver_string(dev) : "NULL",     \
 224                              dev ? dev_name(dev) : "NULL", ## arg);     \
 225                         dump_entry_trace(entry);                        \
 226                 }                                                       \
 227                 if (!show_all_errors && show_num_errors > 0)            \
 228                         show_num_errors -= 1;                           \
 229         } while (0);
 230
 231 /*
 232  * Hash related functions
 233  *
 234  * Every DMA-API request is saved into a struct dma_debug_entry. To
 235  * have quick access to these structs they are stored into a hash.
 236  */
 237 static int hash_fn(struct dma_debug_entry *entry)
 238 {
 239         /*
 240          * Hash function is based on the dma address.
 241          * We use bits 20-27 here as the index into the hash
 242          */
 243         return (entry->dev_addr >> HASH_FN_SHIFT) & HASH_FN_MASK;
 244 }
 245
 246 /*
 247  * Request exclusive access to a hash bucket for a given dma_debug_entry.
 248  */
 249 static struct hash_bucket *get_hash_bucket(struct dma_debug_entry *entry,
 250                                            unsigned long *flags)
 251         __acquires(&dma_entry_hash[idx].lock)
 252 {
 253         int idx = hash_fn(entry);
 254         unsigned long __flags;
 255
 256         spin_lock_irqsave(&dma_entry_hash[idx].lock, __flags);
 257         *flags = __flags;
 258         return &dma_entry_hash[idx];
 259 }
 260
 261 /*
 262  * Give up exclusive access to the hash bucket
 263  */
 264 static void put_hash_bucket(struct hash_bucket *bucket,
 265                             unsigned long flags)
 266         __releases(&bucket->lock)
 267 {
 268         spin_unlock_irqrestore(&bucket->lock, flags);
 269 }
 270
 271 static bool exact_match(struct dma_debug_entry *a, struct dma_debug_entry *b)
 272 {
 273         return ((a->dev_addr == b->dev_addr) &&
 274                 (a->dev == b->dev)) ? true : false;
 275 }
 276
 277 static bool containing_match(struct dma_debug_entry *a,
 278                              struct dma_debug_entry *b)
 279 {
 280         if (a->dev != b->dev)
 281                 return false;
 282
 283         if ((b->dev_addr <= a->dev_addr) &&
 284             ((b->dev_addr + b->size) >= (a->dev_addr + a->size)))
 285                 return true;
 286
 287         return false;
 288 }
 289
 290 /*
 291  * Search a given entry in the hash bucket list
 292  */
 293 static struct dma_debug_entry *__hash_bucket_find(struct hash_bucket *bucket,
 294                                                   struct dma_debug_entry *ref,
 295                                                   match_fn match)
 296 {
 297         struct dma_debug_entry *entry, *ret = NULL;
 298         int matches = 0, match_lvl, last_lvl = -1;
 299
 300         list_for_each_entry(entry, &bucket->list, list) {
 301                 if (!match(ref, entry))
 302                         continue;
 303
 304                 /*
 305                  * Some drivers map the same physical address multiple
 306                  * times. Without a hardware IOMMU this results in the
 307                  * same device addresses being put into the dma-debug
 308                  * hash multiple times too. This can result in false
 309                  * positives being reported. Therefore we implement a
 310                  * best-fit algorithm here which returns the entry from
 311                  * the hash which fits best to the reference value
 312                  * instead of the first-fit.
 313                  */
 314                 matches += 1;
 315                 match_lvl = 0;
 316                 entry->size         == ref->size         ? ++match_lvl : 0;
 317                 entry->type         == ref->type         ? ++match_lvl : 0;
 318                 entry->direction    == ref->direction    ? ++match_lvl : 0;
 319                 entry->sg_call_ents == ref->sg_call_ents ? ++match_lvl : 0;
 320
 321                 if (match_lvl == 4) {
 322                         /* perfect-fit - return the result */
 323                         return entry;
 324                 } else if (match_lvl > last_lvl) {
 325                         /*
 326                          * We found an entry that fits better then the
 327                          * previous one or it is the 1st match.
 328                          */
 329                         last_lvl = match_lvl;
 330                         ret      = entry;
 331                 }
 332         }
 333
 334         /*
 335          * If we have multiple matches but no perfect-fit, just return
 336          * NULL.
 337          */
 338         ret = (matches == 1) ? ret : NULL;
 339
 340         return ret;
 341 }
 342
 343 static struct dma_debug_entry *bucket_find_exact(struct hash_bucket *bucket,
 344                                                  struct dma_debug_entry *ref)
 345 {
 346         return __hash_bucket_find(bucket, ref, exact_match);
 347 }
 348
 349 static struct dma_debug_entry *bucket_find_contain(struct hash_bucket **bucket,
 350                                                    struct dma_debug_entry *ref,
 351                                                    unsigned long *flags)
 352 {
 353
 354         unsigned int max_range = dma_get_max_seg_size(ref->dev);
 355         struct dma_debug_entry *entry, index = *ref;
 356         unsigned int range = 0;
 357
 358         while (range <= max_range) {
 359                 entry = __hash_bucket_find(*bucket, ref, containing_match);
 360
 361                 if (entry)
 362                         return entry;
 363
 364                 /*
 365                  * Nothing found, go back a hash bucket
 366                  */
 367                 put_hash_bucket(*bucket, *flags);
 368                 range          += (1 << HASH_FN_SHIFT);
 369                 index.dev_addr -= (1 << HASH_FN_SHIFT);
 370                 *bucket = get_hash_bucket(&index, flags);
 371         }
 372
 373         return NULL;
 374 }
 375
 376 /*
 377  * Add an entry to a hash bucket
 378  */
 379 static void hash_bucket_add(struct hash_bucket *bucket,
 380                             struct dma_debug_entry *entry)
 381 {
 382         list_add_tail(&entry->list, &bucket->list);
 383 }
 384
 385 /*
 386  * Remove entry from a hash bucket list
 387  */
 388 static void hash_bucket_del(struct dma_debug_entry *entry)
 389 {
 390         list_del(&entry->list);
 391 }
 392
 393 static unsigned long long phys_addr(struct dma_debug_entry *entry)
 394 {
 395         if (entry->type == dma_debug_resource)
 396                 return __pfn_to_phys(entry->pfn) + entry->offset;
 397
 398         return page_to_phys(pfn_to_page(entry->pfn)) + entry->offset;
 399 }
 400
 401 /*
 402  * Dump mapping entries for debugging purposes
 403  */
 404 void debug_dma_dump_mappings(struct device *dev)
 405 {
 406         int idx;
 407
 408         for (idx = 0; idx < HASH_SIZE; idx++) {
 409                 struct hash_bucket *bucket = &dma_entry_hash[idx];
 410                 struct dma_debug_entry *entry;
 411                 unsigned long flags;
 412
 413                 spin_lock_irqsave(&bucket->lock, flags);
 414
 415                 list_for_each_entry(entry, &bucket->list, list) {
 416                         if (!dev || dev == entry->dev) {
 417                                 dev_info(entry->dev,
 418                                          "%s idx %d P=%Lx N=%lx D=%Lx L=%Lx %s %s\n",
 419                                          type2name[entry->type], idx,
 420                                          phys_addr(entry), entry->pfn,
 421                                          entry->dev_addr, entry->size,
 422                                          dir2name[entry->direction],
 423                                          maperr2str[entry->map_err_type]);
 424                         }
 425                 }
 426
 427                 spin_unlock_irqrestore(&bucket->lock, flags);
 428                 cond_resched();
 429         }
 430 }
 431
 432 /*
 433  * For each mapping (initial cacheline in the case of
 434  * dma_alloc_coherent/dma_map_page, initial cacheline in each page of a
 435  * scatterlist, or the cacheline specified in dma_map_single) insert
 436  * into this tree using the cacheline as the key. At
 437  * dma_unmap_{single|sg|page} or dma_free_coherent delete the entry.  If
 438  * the entry already exists at insertion time add a tag as a reference
 439  * count for the overlapping mappings.  For now, the overlap tracking
 440  * just ensures that 'unmaps' balance 'maps' before marking the
 441  * cacheline idle, but we should also be flagging overlaps as an API
 442  * violation.
 443  *
 444  * Memory usage is mostly constrained by the maximum number of available
 445  * dma-debug entries in that we need a free dma_debug_entry before
 446  * inserting into the tree.  In the case of dma_map_page and
 447  * dma_alloc_coherent there is only one dma_debug_entry and one
 448  * dma_active_cacheline entry to track per event.  dma_map_sg(), on the
 449  * other hand, consumes a single dma_debug_entry, but inserts 'nents'
 450  * entries into the tree.
 451  */
 452 static RADIX_TREE(dma_active_cacheline, GFP_NOWAIT);
 453 static DEFINE_SPINLOCK(radix_lock);
 454 #define ACTIVE_CACHELINE_MAX_OVERLAP ((1 << RADIX_TREE_MAX_TAGS) - 1)
 455 #define CACHELINE_PER_PAGE_SHIFT (PAGE_SHIFT - L1_CACHE_SHIFT)
 456 #define CACHELINES_PER_PAGE (1 << CACHELINE_PER_PAGE_SHIFT)
 457
 458 static phys_addr_t to_cacheline_number(struct dma_debug_entry *entry)
 459 {
 460         return (entry->pfn << CACHELINE_PER_PAGE_SHIFT) +
 461                 (entry->offset >> L1_CACHE_SHIFT);
 462 }
 463
 464 static int active_cacheline_read_overlap(phys_addr_t cln)
 465 {
 466         int overlap = 0, i;
 467
 468         for (i = RADIX_TREE_MAX_TAGS - 1; i >= 0; i--)
 469                 if (radix_tree_tag_get(&dma_active_cacheline, cln, i))
 470                         overlap |= 1 << i;
 471         return overlap;
 472 }
 473
 474 static int active_cacheline_set_overlap(phys_addr_t cln, int overlap)
 475 {
 476         int i;
 477
 478         if (overlap > ACTIVE_CACHELINE_MAX_OVERLAP || overlap < 0)
 479                 return overlap;
 480
 481         for (i = RADIX_TREE_MAX_TAGS - 1; i >= 0; i--)
 482                 if (overlap & 1 << i)
 483                         radix_tree_tag_set(&dma_active_cacheline, cln, i);
 484                 else
 485                         radix_tree_tag_clear(&dma_active_cacheline, cln, i);
 486
 487         return overlap;
 488 }
 489
 490 static void active_cacheline_inc_overlap(phys_addr_t cln)
 491 {
 492         int overlap = active_cacheline_read_overlap(cln);
 493
 494         overlap = active_cacheline_set_overlap(cln, ++overlap);
 495
 496         /* If we overflowed the overlap counter then we're potentially
 497          * leaking dma-mappings.
 498          */
 499         WARN_ONCE(overlap > ACTIVE_CACHELINE_MAX_OVERLAP,
 500                   pr_fmt("exceeded %d overlapping mappings of cacheline %pa\n"),
 501                   ACTIVE_CACHELINE_MAX_OVERLAP, &cln);
 502 }
 503
 504 static int active_cacheline_dec_overlap(phys_addr_t cln)
 505 {
 506         int overlap = active_cacheline_read_overlap(cln);
 507
 508         return active_cacheline_set_overlap(cln, --overlap);
 509 }
 510
 511 static int active_cacheline_insert(struct dma_debug_entry *entry)
 512 {
 513         phys_addr_t cln = to_cacheline_number(entry);
 514         unsigned long flags;
 515         int rc;
 516
 517         /* If the device is not writing memory then we don't have any
 518          * concerns about the cpu consuming stale data.  This mitigates
 519          * legitimate usages of overlapping mappings.
 520          */
 521         if (entry->direction == DMA_TO_DEVICE)
 522                 return 0;
 523
 524         spin_lock_irqsave(&radix_lock, flags);
 525         rc = radix_tree_insert(&dma_active_cacheline, cln, entry);
 526         if (rc == -EEXIST)
 527                 active_cacheline_inc_overlap(cln);
 528         spin_unlock_irqrestore(&radix_lock, flags);
 529
 530         return rc;
 531 }
 532
 533 static void active_cacheline_remove(struct dma_debug_entry *entry)
 534 {
 535         phys_addr_t cln = to_cacheline_number(entry);
 536         unsigned long flags;
 537
 538         /* ...mirror the insert case */
 539         if (entry->direction == DMA_TO_DEVICE)
 540                 return;
 541
 542         spin_lock_irqsave(&radix_lock, flags);
 543         /* since we are counting overlaps the final put of the
 544          * cacheline will occur when the overlap count is 0.
 545          * active_cacheline_dec_overlap() returns -1 in that case
 546          */
 547         if (active_cacheline_dec_overlap(cln) < 0)
 548                 radix_tree_delete(&dma_active_cacheline, cln);
 549         spin_unlock_irqrestore(&radix_lock, flags);
 550 }
 551
 552 /*
 553  * Wrapper function for adding an entry to the hash.
 554  * This function takes care of locking itself.
 555  */
 556 static void add_dma_entry(struct dma_debug_entry *entry)
 557 {
 558         struct hash_bucket *bucket;
 559         unsigned long flags;
 560         int rc;
 561
 562         bucket = get_hash_bucket(entry, &flags);
 563         hash_bucket_add(bucket, entry);
 564         put_hash_bucket(bucket, flags);
 565
 566         rc = active_cacheline_insert(entry);
 567         if (rc == -ENOMEM) {
 568                 pr_err("cacheline tracking ENOMEM, dma-debug disabled\n");
 569                 global_disable = true;
 570         }
 571
 572         /* TODO: report -EEXIST errors here as overlapping mappings are
 573          * not supported by the DMA API
 574          */
 575 }
 576
 577 static int dma_debug_create_entries(gfp_t gfp)
 578 {
 579         struct dma_debug_entry *entry;
 580         int i;
 581
 582         entry = (void *)get_zeroed_page(gfp);
 583         if (!entry)
 584                 return -ENOMEM;
 585
 586         for (i = 0; i < DMA_DEBUG_DYNAMIC_ENTRIES; i++)
 587                 list_add_tail(&entry[i].list, &free_entries);
 588
 589         num_free_entries += DMA_DEBUG_DYNAMIC_ENTRIES;
 590         nr_total_entries += DMA_DEBUG_DYNAMIC_ENTRIES;
 591
 592         return 0;
 593 }
 594
 595 static struct dma_debug_entry *__dma_entry_alloc(void)
 596 {
 597         struct dma_debug_entry *entry;
 598
 599         entry = list_entry(free_entries.next, struct dma_debug_entry, list);
 600         list_del(&entry->list);
 601         memset(entry, 0, sizeof(*entry));
 602
 603         num_free_entries -= 1;
 604         if (num_free_entries < min_free_entries)
 605                 min_free_entries = num_free_entries;
 606
 607         return entry;
 608 }
 609
 610 static void __dma_entry_alloc_check_leak(void)
 611 {
 612         u32 tmp = nr_total_entries % nr_prealloc_entries;
 613
 614         /* Shout each time we tick over some multiple of the initial pool */
 615         if (tmp < DMA_DEBUG_DYNAMIC_ENTRIES) {
 616                 pr_info("dma_debug_entry pool grown to %u (%u00%%)\n",
 617                         nr_total_entries,
 618                         (nr_total_entries / nr_prealloc_entries));
 619         }
 620 }
 621
 622 /* struct dma_entry allocator
 623  *
 624  * The next two functions implement the allocator for
 625  * struct dma_debug_entries.
 626  */
 627 static struct dma_debug_entry *dma_entry_alloc(void)
 628 {
 629         struct dma_debug_entry *entry;
 630         unsigned long flags;
 631
 632         spin_lock_irqsave(&free_entries_lock, flags);
 633         if (num_free_entries == 0) {
 634                 if (dma_debug_create_entries(GFP_ATOMIC)) {
 635                         global_disable = true;
 636                         spin_unlock_irqrestore(&free_entries_lock, flags);
 637                         pr_err("debugging out of memory - disabling\n");
 638                         return NULL;
 639                 }
 640                 __dma_entry_alloc_check_leak();
 641         }
 642
 643         entry = __dma_entry_alloc();
 644
 645         spin_unlock_irqrestore(&free_entries_lock, flags);
 646
 647 #ifdef CONFIG_STACKTRACE
 648         entry->stack_len = stack_trace_save(entry->stack_entries,
 649                                             ARRAY_SIZE(entry->stack_entries),
 650                                             1);
 651 #endif
 652         return entry;
 653 }
 654
 655 static void dma_entry_free(struct dma_debug_entry *entry)
 656 {
 657         unsigned long flags;
 658
 659         active_cacheline_remove(entry);
 660
 661         /*
 662          * add to beginning of the list - this way the entries are
 663          * more likely cache hot when they are reallocated.
 664          */
 665         spin_lock_irqsave(&free_entries_lock, flags);
 666         list_add(&entry->list, &free_entries);
 667         num_free_entries += 1;
 668         spin_unlock_irqrestore(&free_entries_lock, flags);
 669 }
 670
 671 /*
 672  * DMA-API debugging init code
 673  *
 674  * The init code does two things:
 675  *   1. Initialize core data structures
 676  *   2. Preallocate a given number of dma_debug_entry structs
 677  */
 678
 679 static ssize_t filter_read(struct file *file, char __user *user_buf,
 680                            size_t count, loff_t *ppos)
 681 {
 682         char buf[NAME_MAX_LEN + 1];
 683         unsigned long flags;
 684         int len;
 685
 686         if (!current_driver_name[0])
 687                 return 0;
 688
 689         /*
 690          * We can't copy to userspace directly because current_driver_name can
 691          * only be read under the driver_name_lock with irqs disabled. So
 692          * create a temporary copy first.
 693          */
 694         read_lock_irqsave(&driver_name_lock, flags);
 695         len = scnprintf(buf, NAME_MAX_LEN + 1, "%s\n", current_driver_name);
 696         read_unlock_irqrestore(&driver_name_lock, flags);
 697
 698         return simple_read_from_buffer(user_buf, count, ppos, buf, len);
 699 }
 700
 701 static ssize_t filter_write(struct file *file, const char __user *userbuf,
 702                             size_t count, loff_t *ppos)
 703 {
 704         char buf[NAME_MAX_LEN];
 705         unsigned long flags;
 706         size_t len;
 707         int i;
 708
 709         /*
 710          * We can't copy from userspace directly. Access to
 711          * current_driver_name is protected with a write_lock with irqs
 712          * disabled. Since copy_from_user can fault and may sleep we
 713          * need to copy to temporary buffer first
 714          */
 715         len = min(count, (size_t)(NAME_MAX_LEN - 1));
 716         if (copy_from_user(buf, userbuf, len))
 717                 return -EFAULT;
 718
 719         buf[len] = 0;
 720
 721         write_lock_irqsave(&driver_name_lock, flags);
 722
 723         /*
 724          * Now handle the string we got from userspace very carefully.
 725          * The rules are:
 726          *         - only use the first token we got
 727          *         - token delimiter is everything looking like a space
 728          *           character (' ', '\n', '\t' ...)
 729          *
 730          */
 731         if (!isalnum(buf[0])) {
 732                 /*
 733                  * If the first character userspace gave us is not
 734                  * alphanumerical then assume the filter should be
 735                  * switched off.
 736                  */
 737                 if (current_driver_name[0])
 738                         pr_info("switching off dma-debug driver filter\n");
 739                 current_driver_name[0] = 0;
 740                 current_driver = NULL;
 741                 goto out_unlock;
 742         }
 743
 744         /*
 745          * Now parse out the first token and use it as the name for the
 746          * driver to filter for.
 747          */
 748         for (i = 0; i < NAME_MAX_LEN - 1; ++i) {
 749                 current_driver_name[i] = buf[i];
 750                 if (isspace(buf[i]) || buf[i] == ' ' || buf[i] == 0)
 751                         break;
 752         }
 753         current_driver_name[i] = 0;
 754         current_driver = NULL;
 755
 756         pr_info("enable driver filter for driver [%s]\n",
 757                 current_driver_name);
 758
 759 out_unlock:
 760         write_unlock_irqrestore(&driver_name_lock, flags);
 761
 762         return count;
 763 }
 764
 765 static const struct file_operations filter_fops = {
 766         .read  = filter_read,
 767         .write = filter_write,
 768         .llseek = default_llseek,
 769 };
 770
 771 static int dump_show(struct seq_file *seq, void *v)
 772 {
 773         int idx;
 774
 775         for (idx = 0; idx < HASH_SIZE; idx++) {
 776                 struct hash_bucket *bucket = &dma_entry_hash[idx];
 777                 struct dma_debug_entry *entry;
 778                 unsigned long flags;
 779
 780                 spin_lock_irqsave(&bucket->lock, flags);
 781                 list_for_each_entry(entry, &bucket->list, list) {
 782                         seq_printf(seq,
 783                                    "%s %s %s idx %d P=%llx N=%lx D=%llx L=%llx %s %s\n",
 784                                    dev_name(entry->dev),
 785                                    dev_driver_string(entry->dev),
 786                                    type2name[entry->type], idx,
 787                                    phys_addr(entry), entry->pfn,
 788                                    entry->dev_addr, entry->size,
 789                                    dir2name[entry->direction],
 790                                    maperr2str[entry->map_err_type]);
 791                 }
 792                 spin_unlock_irqrestore(&bucket->lock, flags);
 793         }
 794         return 0;
 795 }
 796 DEFINE_SHOW_ATTRIBUTE(dump);
 797
 798 static void dma_debug_fs_init(void)
 799 {
 800         struct dentry *dentry = debugfs_create_dir("dma-api", NULL);
 801
 802         debugfs_create_bool("disabled", 0444, dentry, &global_disable);
 803         debugfs_create_u32("error_count", 0444, dentry, &error_count);
 804         debugfs_create_u32("all_errors", 0644, dentry, &show_all_errors);
 805         debugfs_create_u32("num_errors", 0644, dentry, &show_num_errors);
 806         debugfs_create_u32("num_free_entries", 0444, dentry, &num_free_entries);
 807         debugfs_create_u32("min_free_entries", 0444, dentry, &min_free_entries);
 808         debugfs_create_u32("nr_total_entries", 0444, dentry, &nr_total_entries);
 809         debugfs_create_file("driver_filter", 0644, dentry, NULL, &filter_fops);
 810         debugfs_create_file("dump", 0444, dentry, NULL, &dump_fops);
 811 }
 812
 813 static int device_dma_allocations(struct device *dev, struct dma_debug_entry **out_entry)
 814 {
 815         struct dma_debug_entry *entry;
 816         unsigned long flags;
 817         int count = 0, i;
 818
 819         for (i = 0; i < HASH_SIZE; ++i) {
 820                 spin_lock_irqsave(&dma_entry_hash[i].lock, flags);
 821                 list_for_each_entry(entry, &dma_entry_hash[i].list, list) {
 822                         if (entry->dev == dev) {
 823                                 count += 1;
 824                                 *out_entry = entry;
 825                         }
 826                 }
 827                 spin_unlock_irqrestore(&dma_entry_hash[i].lock, flags);
 828         }
 829
 830         return count;
 831 }
 832
 833 static int dma_debug_device_change(struct notifier_block *nb, unsigned long action, void *data)
 834 {
 835         struct device *dev = data;
 836         struct dma_debug_entry *entry;
 837         int count;
 838
 839         if (dma_debug_disabled())
 840                 return 0;
 841
 842         switch (action) {
 843         case BUS_NOTIFY_UNBOUND_DRIVER:
 844                 count = device_dma_allocations(dev, &entry);
 845                 if (count == 0)
 846                         break;
 847                 err_printk(dev, entry, "device driver has pending "
 848                                 "DMA allocations while released from device "
 849                                 "[count=%d]\n"
 850                                 "One of leaked entries details: "
 851                                 "[device address=0x%016llx] [size=%llu bytes] "
 852                                 "[mapped with %s] [mapped as %s]\n",
 853                         count, entry->dev_addr, entry->size,
 854                         dir2name[entry->direction], type2name[entry->type]);
 855                 break;
 856         default:
 857                 break;
 858         }
 859
 860         return 0;
 861 }
 862
 863 void dma_debug_add_bus(struct bus_type *bus)
 864 {
 865         struct notifier_block *nb;
 866
 867         if (dma_debug_disabled())
 868                 return;
 869
 870         nb = kzalloc(sizeof(struct notifier_block), GFP_KERNEL);
 871         if (nb == NULL) {
 872                 pr_err("dma_debug_add_bus: out of memory\n");
 873                 return;
 874         }
 875
 876         nb->notifier_call = dma_debug_device_change;
 877
 878         bus_register_notifier(bus, nb);
 879 }
 880
 881 static int dma_debug_init(void)
 882 {
 883         int i, nr_pages;
 884
 885         /* Do not use dma_debug_initialized here, since we really want to be
 886          * called to set dma_debug_initialized
 887          */
 888         if (global_disable)
 889                 return 0;
 890
 891         for (i = 0; i < HASH_SIZE; ++i) {
 892                 INIT_LIST_HEAD(&dma_entry_hash[i].list);
 893                 spin_lock_init(&dma_entry_hash[i].lock);
 894         }
 895
 896         dma_debug_fs_init();
 897
 898         nr_pages = DIV_ROUND_UP(nr_prealloc_entries, DMA_DEBUG_DYNAMIC_ENTRIES);
 899         for (i = 0; i < nr_pages; ++i)
 900                 dma_debug_create_entries(GFP_KERNEL);
 901         if (num_free_entries >= nr_prealloc_entries) {
 902                 pr_info("preallocated %d debug entries\n", nr_total_entries);
 903         } else if (num_free_entries > 0) {
 904                 pr_warn("%d debug entries requested but only %d allocated\n",
 905                         nr_prealloc_entries, nr_total_entries);
 906         } else {
 907                 pr_err("debugging out of memory error - disabled\n");
 908                 global_disable = true;
 909
 910                 return 0;
 911         }
 912         min_free_entries = num_free_entries;
 913
 914         dma_debug_initialized = true;
 915
 916         pr_info("debugging enabled by kernel config\n");
 917         return 0;
 918 }
 919 core_initcall(dma_debug_init);
 920
 921 static __init int dma_debug_cmdline(char *str)
 922 {
 923         if (!str)
 924                 return -EINVAL;
 925
 926         if (strncmp(str, "off", 3) == 0) {
 927                 pr_info("debugging disabled on kernel command line\n");
 928                 global_disable = true;
 929         }
 930
 931         return 0;
 932 }
 933
 934 static __init int dma_debug_entries_cmdline(char *str)
 935 {
 936         if (!str)
 937                 return -EINVAL;
 938         if (!get_option(&str, &nr_prealloc_entries))
 939                 nr_prealloc_entries = PREALLOC_DMA_DEBUG_ENTRIES;
 940         return 0;
 941 }
 942
 943 __setup("dma_debug=", dma_debug_cmdline);
 944 __setup("dma_debug_entries=", dma_debug_entries_cmdline);
 945
 946 static void check_unmap(struct dma_debug_entry *ref)
 947 {
 948         struct dma_debug_entry *entry;
 949         struct hash_bucket *bucket;
 950         unsigned long flags;
 951
 952         bucket = get_hash_bucket(ref, &flags);
 953         entry = bucket_find_exact(bucket, ref);
 954
 955         if (!entry) {
 956                 /* must drop lock before calling dma_mapping_error */
 957                 put_hash_bucket(bucket, flags);
 958
 959                 if (dma_mapping_error(ref->dev, ref->dev_addr)) {
 960                         err_printk(ref->dev, NULL,
 961                                    "device driver tries to free an "
 962                                    "invalid DMA memory address\n");
 963                 } else {
 964                         err_printk(ref->dev, NULL,
 965                                    "device driver tries to free DMA "
 966                                    "memory it has not allocated [device "
 967                                    "address=0x%016llx] [size=%llu bytes]\n",
 968                                    ref->dev_addr, ref->size);
 969                 }
 970                 return;
 971         }
 972
 973         if (ref->size != entry->size) {
 974                 err_printk(ref->dev, entry, "device driver frees "
 975                            "DMA memory with different size "
 976                            "[device address=0x%016llx] [map size=%llu bytes] "
 977                            "[unmap size=%llu bytes]\n",
 978                            ref->dev_addr, entry->size, ref->size);
 979         }
 980
 981         if (ref->type != entry->type) {
 982                 err_printk(ref->dev, entry, "device driver frees "
 983                            "DMA memory with wrong function "
 984                            "[device address=0x%016llx] [size=%llu bytes] "
 985                            "[mapped as %s] [unmapped as %s]\n",
 986                            ref->dev_addr, ref->size,
 987                            type2name[entry->type], type2name[ref->type]);
 988         } else if ((entry->type == dma_debug_coherent) &&
 989                    (phys_addr(ref) != phys_addr(entry))) {
 990                 err_printk(ref->dev, entry, "device driver frees "
 991                            "DMA memory with different CPU address "
 992                            "[device address=0x%016llx] [size=%llu bytes] "
 993                            "[cpu alloc address=0x%016llx] "
 994                            "[cpu free address=0x%016llx]",
 995                            ref->dev_addr, ref->size,
 996                            phys_addr(entry),
 997                            phys_addr(ref));
 998         }
 999
1000         if (ref->sg_call_ents && ref->type == dma_debug_sg &&
1001             ref->sg_call_ents != entry->sg_call_ents) {
1002                 err_printk(ref->dev, entry, "device driver frees "
1003                            "DMA sg list with different entry count "
1004                            "[map count=%d] [unmap count=%d]\n",
1005                            entry->sg_call_ents, ref->sg_call_ents);
1006         }
1007
1008         /*
1009          * This may be no bug in reality - but most implementations of the
1010          * DMA API don't handle this properly, so check for it here
1011          */
1012         if (ref->direction != entry->direction) {
1013                 err_printk(ref->dev, entry, "device driver frees "
1014                            "DMA memory with different direction "
1015                            "[device address=0x%016llx] [size=%llu bytes] "
1016                            "[mapped with %s] [unmapped with %s]\n",
1017                            ref->dev_addr, ref->size,
1018                            dir2name[entry->direction],
1019                            dir2name[ref->direction]);
1020         }
1021
1022         /*
1023          * Drivers should use dma_mapping_error() to check the returned
1024          * addresses of dma_map_single() and dma_map_page().
1025          * If not, print this warning message. See Documentation/core-api/dma-api.rst.
1026          */
1027         if (entry->map_err_type == MAP_ERR_NOT_CHECKED) {
1028                 err_printk(ref->dev, entry,
1029                            "device driver failed to check map error"
1030                            "[device address=0x%016llx] [size=%llu bytes] "
1031                            "[mapped as %s]",
1032                            ref->dev_addr, ref->size,
1033                            type2name[entry->type]);
1034         }
1035
1036         hash_bucket_del(entry);
1037         dma_entry_free(entry);
1038
1039         put_hash_bucket(bucket, flags);
1040 }
1041
1042 static void check_for_stack(struct device *dev,
1043                             struct page *page, size_t offset)
1044 {
1045         void *addr;
1046         struct vm_struct *stack_vm_area = task_stack_vm_area(current);
1047
1048         if (!stack_vm_area) {
1049                 /* Stack is direct-mapped. */
1050                 if (PageHighMem(page))
1051                         return;
1052                 addr = page_address(page) + offset;
1053                 if (object_is_on_stack(addr))
1054                         err_printk(dev, NULL, "device driver maps memory from stack [addr=%p]\n", addr);
1055         } else {
1056                 /* Stack is vmalloced. */
1057                 int i;
1058
1059                 for (i = 0; i < stack_vm_area->nr_pages; i++) {
1060                         if (page != stack_vm_area->pages[i])
1061                                 continue;
1062
1063                         addr = (u8 *)current->stack + i * PAGE_SIZE + offset;
1064                         err_printk(dev, NULL, "device driver maps memory from stack [probable addr=%p]\n", addr);
1065                         break;
1066                 }
1067         }
1068 }
1069
1070 static inline bool overlap(void *addr, unsigned long len, void *start, void *end)
1071 {
1072         unsigned long a1 = (unsigned long)addr;
1073         unsigned long b1 = a1 + len;
1074         unsigned long a2 = (unsigned long)start;
1075         unsigned long b2 = (unsigned long)end;
1076
1077         return !(b1 <= a2 || a1 >= b2);
1078 }
1079
1080 static void check_for_illegal_area(struct device *dev, void *addr, unsigned long len)
1081 {
1082         if (overlap(addr, len, _stext, _etext) ||
1083             overlap(addr, len, __start_rodata, __end_rodata))
1084                 err_printk(dev, NULL, "device driver maps memory from kernel text or rodata [addr=%p] [len=%lu]\n", addr, len);
1085 }
1086
1087 static void check_sync(struct device *dev,
1088                        struct dma_debug_entry *ref,
1089                        bool to_cpu)
1090 {
1091         struct dma_debug_entry *entry;
1092         struct hash_bucket *bucket;
1093         unsigned long flags;
1094
1095         bucket = get_hash_bucket(ref, &flags);
1096
1097         entry = bucket_find_contain(&bucket, ref, &flags);
1098
1099         if (!entry) {
1100                 err_printk(dev, NULL, "device driver tries "
1101                                 "to sync DMA memory it has not allocated "
1102                                 "[device address=0x%016llx] [size=%llu bytes]\n",
1103                                 (unsigned long long)ref->dev_addr, ref->size);
1104                 goto out;
1105         }
1106
1107         if (ref->size > entry->size) {
1108                 err_printk(dev, entry, "device driver syncs"
1109                                 " DMA memory outside allocated range "
1110                                 "[device address=0x%016llx] "
1111                                 "[allocation size=%llu bytes] "
1112                                 "[sync offset+size=%llu]\n",
1113                                 entry->dev_addr, entry->size,
1114                                 ref->size);
1115         }
1116
1117         if (entry->direction == DMA_BIDIRECTIONAL)
1118                 goto out;
1119
1120         if (ref->direction != entry->direction) {
1121                 err_printk(dev, entry, "device driver syncs "
1122                                 "DMA memory with different direction "
1123                                 "[device address=0x%016llx] [size=%llu bytes] "
1124                                 "[mapped with %s] [synced with %s]\n",
1125                                 (unsigned long long)ref->dev_addr, entry->size,
1126                                 dir2name[entry->direction],
1127                                 dir2name[ref->direction]);
1128         }
1129
1130         if (to_cpu && !(entry->direction == DMA_FROM_DEVICE) &&
1131                       !(ref->direction == DMA_TO_DEVICE))
1132                 err_printk(dev, entry, "device driver syncs "
1133                                 "device read-only DMA memory for cpu "
1134                                 "[device address=0x%016llx] [size=%llu bytes] "
1135                                 "[mapped with %s] [synced with %s]\n",
1136                                 (unsigned long long)ref->dev_addr, entry->size,
1137                                 dir2name[entry->direction],
1138                                 dir2name[ref->direction]);
1139
1140         if (!to_cpu && !(entry->direction == DMA_TO_DEVICE) &&
1141                        !(ref->direction == DMA_FROM_DEVICE))
1142                 err_printk(dev, entry, "device driver syncs "
1143                                 "device write-only DMA memory to device "
1144                                 "[device address=0x%016llx] [size=%llu bytes] "
1145                                 "[mapped with %s] [synced with %s]\n",
1146                                 (unsigned long long)ref->dev_addr, entry->size,
1147                                 dir2name[entry->direction],
1148                                 dir2name[ref->direction]);
1149
1150         if (ref->sg_call_ents && ref->type == dma_debug_sg &&
1151             ref->sg_call_ents != entry->sg_call_ents) {
1152                 err_printk(ref->dev, entry, "device driver syncs "
1153                            "DMA sg list with different entry count "
1154                            "[map count=%d] [sync count=%d]\n",
1155                            entry->sg_call_ents, ref->sg_call_ents);
1156         }
1157
1158 out:
1159         put_hash_bucket(bucket, flags);
1160 }
1161
1162 static void check_sg_segment(struct device *dev, struct scatterlist *sg)
1163 {
1164 #ifdef CONFIG_DMA_API_DEBUG_SG
1165         unsigned int max_seg = dma_get_max_seg_size(dev);
1166         u64 start, end, boundary = dma_get_seg_boundary(dev);
1167
1168         /*
1169          * Either the driver forgot to set dma_parms appropriately, or
1170          * whoever generated the list forgot to check them.
1171          */
1172         if (sg->length > max_seg)
1173                 err_printk(dev, NULL, "mapping sg segment longer than device claims to support [len=%u] [max=%u]\n",
1174                            sg->length, max_seg);
1175         /*
1176          * In some cases this could potentially be the DMA API
1177          * implementation's fault, but it would usually imply that
1178          * the scatterlist was built inappropriately to begin with.
1179          */
1180         start = sg_dma_address(sg);
1181         end = start + sg_dma_len(sg) - 1;
1182         if ((start ^ end) & ~boundary)
1183                 err_printk(dev, NULL, "mapping sg segment across boundary [start=0x%016llx] [end=0x%016llx] [boundary=0x%016llx]\n",
1184                            start, end, boundary);
1185 #endif
1186 }
1187
1188 void debug_dma_map_single(struct device *dev, const void *addr,
1189                             unsigned long len)
1190 {
1191         if (unlikely(dma_debug_disabled()))
1192                 return;
1193
1194         if (!virt_addr_valid(addr))
1195                 err_printk(dev, NULL, "device driver maps memory from invalid area [addr=%p] [len=%lu]\n",
1196                            addr, len);
1197
1198         if (is_vmalloc_addr(addr))
1199                 err_printk(dev, NULL, "device driver maps memory from vmalloc area [addr=%p] [len=%lu]\n",
1200                            addr, len);
1201 }
1202 EXPORT_SYMBOL(debug_dma_map_single);
1203
1204 void debug_dma_map_page(struct device *dev, struct page *page, size_t offset,
1205                         size_t size, int direction, dma_addr_t dma_addr)
1206 {
1207         struct dma_debug_entry *entry;
1208
1209         if (unlikely(dma_debug_disabled()))
1210                 return;
1211
1212         if (dma_mapping_error(dev, dma_addr))
1213                 return;
1214
1215         entry = dma_entry_alloc();
1216         if (!entry)
1217                 return;
1218
1219         entry->dev       = dev;
1220         entry->type      = dma_debug_single;
1221         entry->pfn       = page_to_pfn(page);
1222         entry->offset    = offset,
1223         entry->dev_addr  = dma_addr;
1224         entry->size      = size;
1225         entry->direction = direction;
1226         entry->map_err_type = MAP_ERR_NOT_CHECKED;
1227
1228         check_for_stack(dev, page, offset);
1229
1230         if (!PageHighMem(page)) {
1231                 void *addr = page_address(page) + offset;
1232
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(dma_debug_disabled()))
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)
1280 {
1281         struct dma_debug_entry ref = {
1282                 .type           = dma_debug_single,
1283                 .dev            = dev,
1284                 .dev_addr       = addr,
1285                 .size           = size,
1286                 .direction      = direction,
1287         };
1288
1289         if (unlikely(dma_debug_disabled()))
1290                 return;
1291         check_unmap(&ref);
1292 }
1293 EXPORT_SYMBOL(debug_dma_unmap_page);
1294
1295 void debug_dma_map_sg(struct device *dev, struct scatterlist *sg,
1296                       int nents, int mapped_ents, int direction)
1297 {
1298         struct dma_debug_entry *entry;
1299         struct scatterlist *s;
1300         int i;
1301
1302         if (unlikely(dma_debug_disabled()))
1303                 return;
1304
1305         for_each_sg(sg, s, mapped_ents, i) {
1306                 entry = dma_entry_alloc();
1307                 if (!entry)
1308                         return;
1309
1310                 entry->type           = dma_debug_sg;
1311                 entry->dev            = dev;
1312                 entry->pfn            = page_to_pfn(sg_page(s));
1313                 entry->offset         = s->offset,
1314                 entry->size           = sg_dma_len(s);
1315                 entry->dev_addr       = sg_dma_address(s);
1316                 entry->direction      = direction;
1317                 entry->sg_call_ents   = nents;
1318                 entry->sg_mapped_ents = mapped_ents;
1319
1320                 check_for_stack(dev, sg_page(s), s->offset);
1321
1322                 if (!PageHighMem(sg_page(s))) {
1323                         check_for_illegal_area(dev, sg_virt(s), sg_dma_len(s));
1324                 }
1325
1326                 check_sg_segment(dev, s);
1327
1328                 add_dma_entry(entry);
1329         }
1330 }
1331 EXPORT_SYMBOL(debug_dma_map_sg);
1332
1333 static int get_nr_mapped_entries(struct device *dev,
1334                                  struct dma_debug_entry *ref)
1335 {
1336         struct dma_debug_entry *entry;
1337         struct hash_bucket *bucket;
1338         unsigned long flags;
1339         int mapped_ents;
1340
1341         bucket       = get_hash_bucket(ref, &flags);
1342         entry        = bucket_find_exact(bucket, ref);
1343         mapped_ents  = 0;
1344
1345         if (entry)
1346                 mapped_ents = entry->sg_mapped_ents;
1347         put_hash_bucket(bucket, flags);
1348
1349         return mapped_ents;
1350 }
1351
1352 void debug_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
1353                         int nelems, int dir)
1354 {
1355         struct scatterlist *s;
1356         int mapped_ents = 0, i;
1357
1358         if (unlikely(dma_debug_disabled()))
1359                 return;
1360
1361         for_each_sg(sglist, s, nelems, i) {
1362
1363                 struct dma_debug_entry ref = {
1364                         .type           = dma_debug_sg,
1365                         .dev            = dev,
1366                         .pfn            = page_to_pfn(sg_page(s)),
1367                         .offset         = s->offset,
1368                         .dev_addr       = sg_dma_address(s),
1369                         .size           = sg_dma_len(s),
1370                         .direction      = dir,
1371                         .sg_call_ents   = nelems,
1372                 };
1373
1374                 if (mapped_ents && i >= mapped_ents)
1375                         break;
1376
1377                 if (!i)
1378                         mapped_ents = get_nr_mapped_entries(dev, &ref);
1379
1380                 check_unmap(&ref);
1381         }
1382 }
1383 EXPORT_SYMBOL(debug_dma_unmap_sg);
1384
1385 void debug_dma_alloc_coherent(struct device *dev, size_t size,
1386                               dma_addr_t dma_addr, void *virt)
1387 {
1388         struct dma_debug_entry *entry;
1389
1390         if (unlikely(dma_debug_disabled()))
1391                 return;
1392
1393         if (unlikely(virt == NULL))
1394                 return;
1395
1396         /* handle vmalloc and linear addresses */
1397         if (!is_vmalloc_addr(virt) && !virt_addr_valid(virt))
1398                 return;
1399
1400         entry = dma_entry_alloc();
1401         if (!entry)
1402                 return;
1403
1404         entry->type      = dma_debug_coherent;
1405         entry->dev       = dev;
1406         entry->offset    = offset_in_page(virt);
1407         entry->size      = size;
1408         entry->dev_addr  = dma_addr;
1409         entry->direction = DMA_BIDIRECTIONAL;
1410
1411         if (is_vmalloc_addr(virt))
1412                 entry->pfn = vmalloc_to_pfn(virt);
1413         else
1414                 entry->pfn = page_to_pfn(virt_to_page(virt));
1415
1416         add_dma_entry(entry);
1417 }
1418
1419 void debug_dma_free_coherent(struct device *dev, size_t size,
1420                          void *virt, dma_addr_t addr)
1421 {
1422         struct dma_debug_entry ref = {
1423                 .type           = dma_debug_coherent,
1424                 .dev            = dev,
1425                 .offset         = offset_in_page(virt),
1426                 .dev_addr       = addr,
1427                 .size           = size,
1428                 .direction      = DMA_BIDIRECTIONAL,
1429         };
1430
1431         /* handle vmalloc and linear addresses */
1432         if (!is_vmalloc_addr(virt) && !virt_addr_valid(virt))
1433                 return;
1434
1435         if (is_vmalloc_addr(virt))
1436                 ref.pfn = vmalloc_to_pfn(virt);
1437         else
1438                 ref.pfn = page_to_pfn(virt_to_page(virt));
1439
1440         if (unlikely(dma_debug_disabled()))
1441                 return;
1442
1443         check_unmap(&ref);
1444 }
1445
1446 void debug_dma_map_resource(struct device *dev, phys_addr_t addr, size_t size,
1447                             int direction, dma_addr_t dma_addr)
1448 {
1449         struct dma_debug_entry *entry;
1450
1451         if (unlikely(dma_debug_disabled()))
1452                 return;
1453
1454         entry = dma_entry_alloc();
1455         if (!entry)
1456                 return;
1457
1458         entry->type             = dma_debug_resource;
1459         entry->dev              = dev;
1460         entry->pfn              = PHYS_PFN(addr);
1461         entry->offset           = offset_in_page(addr);
1462         entry->size             = size;
1463         entry->dev_addr         = dma_addr;
1464         entry->direction        = direction;
1465         entry->map_err_type     = MAP_ERR_NOT_CHECKED;
1466
1467         add_dma_entry(entry);
1468 }
1469 EXPORT_SYMBOL(debug_dma_map_resource);
1470
1471 void debug_dma_unmap_resource(struct device *dev, dma_addr_t dma_addr,
1472                               size_t size, int direction)
1473 {
1474         struct dma_debug_entry ref = {
1475                 .type           = dma_debug_resource,
1476                 .dev            = dev,
1477                 .dev_addr       = dma_addr,
1478                 .size           = size,
1479                 .direction      = direction,
1480         };
1481
1482         if (unlikely(dma_debug_disabled()))
1483                 return;
1484
1485         check_unmap(&ref);
1486 }
1487 EXPORT_SYMBOL(debug_dma_unmap_resource);
1488
1489 void debug_dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_handle,
1490                                    size_t size, int direction)
1491 {
1492         struct dma_debug_entry ref;
1493
1494         if (unlikely(dma_debug_disabled()))
1495                 return;
1496
1497         ref.type         = dma_debug_single;
1498         ref.dev          = dev;
1499         ref.dev_addr     = dma_handle;
1500         ref.size         = size;
1501         ref.direction    = direction;
1502         ref.sg_call_ents = 0;
1503
1504         check_sync(dev, &ref, true);
1505 }
1506 EXPORT_SYMBOL(debug_dma_sync_single_for_cpu);
1507
1508 void debug_dma_sync_single_for_device(struct device *dev,
1509                                       dma_addr_t dma_handle, size_t size,
1510                                       int direction)
1511 {
1512         struct dma_debug_entry ref;
1513
1514         if (unlikely(dma_debug_disabled()))
1515                 return;
1516
1517         ref.type         = dma_debug_single;
1518         ref.dev          = dev;
1519         ref.dev_addr     = dma_handle;
1520         ref.size         = size;
1521         ref.direction    = direction;
1522         ref.sg_call_ents = 0;
1523
1524         check_sync(dev, &ref, false);
1525 }
1526 EXPORT_SYMBOL(debug_dma_sync_single_for_device);
1527
1528 void debug_dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
1529                                int nelems, int direction)
1530 {
1531         struct scatterlist *s;
1532         int mapped_ents = 0, i;
1533
1534         if (unlikely(dma_debug_disabled()))
1535                 return;
1536
1537         for_each_sg(sg, s, nelems, i) {
1538
1539                 struct dma_debug_entry ref = {
1540                         .type           = dma_debug_sg,
1541                         .dev            = dev,
1542                         .pfn            = page_to_pfn(sg_page(s)),
1543                         .offset         = s->offset,
1544                         .dev_addr       = sg_dma_address(s),
1545                         .size           = sg_dma_len(s),
1546                         .direction      = direction,
1547                         .sg_call_ents   = nelems,
1548                 };
1549
1550                 if (!i)
1551                         mapped_ents = get_nr_mapped_entries(dev, &ref);
1552
1553                 if (i >= mapped_ents)
1554                         break;
1555
1556                 check_sync(dev, &ref, true);
1557         }
1558 }
1559 EXPORT_SYMBOL(debug_dma_sync_sg_for_cpu);
1560
1561 void debug_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
1562                                   int nelems, int direction)
1563 {
1564         struct scatterlist *s;
1565         int mapped_ents = 0, i;
1566
1567         if (unlikely(dma_debug_disabled()))
1568                 return;
1569
1570         for_each_sg(sg, s, nelems, i) {
1571
1572                 struct dma_debug_entry ref = {
1573                         .type           = dma_debug_sg,
1574                         .dev            = dev,
1575                         .pfn            = page_to_pfn(sg_page(s)),
1576                         .offset         = s->offset,
1577                         .dev_addr       = sg_dma_address(s),
1578                         .size           = sg_dma_len(s),
1579                         .direction      = direction,
1580                         .sg_call_ents   = nelems,
1581                 };
1582                 if (!i)
1583                         mapped_ents = get_nr_mapped_entries(dev, &ref);
1584
1585                 if (i >= mapped_ents)
1586                         break;
1587
1588                 check_sync(dev, &ref, false);
1589         }
1590 }
1591 EXPORT_SYMBOL(debug_dma_sync_sg_for_device);
1592
1593 static int __init dma_debug_driver_setup(char *str)
1594 {
1595         int i;
1596
1597         for (i = 0; i < NAME_MAX_LEN - 1; ++i, ++str) {
1598                 current_driver_name[i] = *str;
1599                 if (*str == 0)
1600                         break;
1601         }
1602
1603         if (current_driver_name[0])
1604                 pr_info("enable driver filter for driver [%s]\n",
1605                         current_driver_name);
1606
1607
1608         return 1;
1609 }
1610 __setup("dma_debug_driver=", dma_debug_driver_setup);