kernel/dma/debug.c

   1 /*
   2  * Copyright (C) 2008 Advanced Micro Devices, Inc.
   3  *
   4  * Author: Joerg Roedel <joerg.roedel@amd.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License version 2 as published
   8  * by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  18  */
  19
  20 #include <linux/sched/task_stack.h>
  21 #include <linux/scatterlist.h>
  22 #include <linux/dma-mapping.h>
  23 #include <linux/sched/task.h>
  24 #include <linux/stacktrace.h>
  25 #include <linux/dma-debug.h>
  26 #include <linux/spinlock.h>
  27 #include <linux/vmalloc.h>
  28 #include <linux/debugfs.h>
  29 #include <linux/uaccess.h>
  30 #include <linux/export.h>
  31 #include <linux/device.h>
  32 #include <linux/types.h>
  33 #include <linux/sched.h>
  34 #include <linux/ctype.h>
  35 #include <linux/list.h>
  36 #include <linux/slab.h>
  37
  38 #include <asm/sections.h>
  39
  40 #define HASH_SIZE       1024ULL
  41 #define HASH_FN_SHIFT   13
  42 #define HASH_FN_MASK    (HASH_SIZE - 1)
  43
  44 /* allow architectures to override this if absolutely required */
  45 #ifndef PREALLOC_DMA_DEBUG_ENTRIES
  46 #define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16)
  47 #endif
  48
  49 enum {
  50         dma_debug_single,
  51         dma_debug_page,
  52         dma_debug_sg,
  53         dma_debug_coherent,
  54         dma_debug_resource,
  55 };
  56
  57 enum map_err_types {
  58         MAP_ERR_CHECK_NOT_APPLICABLE,
  59         MAP_ERR_NOT_CHECKED,
  60         MAP_ERR_CHECKED,
  61 };
  62
  63 #define DMA_DEBUG_STACKTRACE_ENTRIES 5
  64
  65 /**
  66  * struct dma_debug_entry - track a dma_map* or dma_alloc_coherent mapping
  67  * @list: node on pre-allocated free_entries list
  68  * @dev: 'dev' argument to dma_map_{page|single|sg} or dma_alloc_coherent
  69  * @type: single, page, sg, coherent
  70  * @pfn: page frame of the start address
  71  * @offset: offset of mapping relative to pfn
  72  * @size: length of the mapping
  73  * @direction: enum dma_data_direction
  74  * @sg_call_ents: 'nents' from dma_map_sg
  75  * @sg_mapped_ents: 'mapped_ents' from dma_map_sg
  76  * @map_err_type: track whether dma_mapping_error() was checked
  77  * @stacktrace: support backtraces when a violation is detected
  78  */
  79 struct dma_debug_entry {
  80         struct list_head list;
  81         struct device    *dev;
  82         int              type;
  83         unsigned long    pfn;
  84         size_t           offset;
  85         u64              dev_addr;
  86         u64              size;
  87         int              direction;
  88         int              sg_call_ents;
  89         int              sg_mapped_ents;
  90         enum map_err_types  map_err_type;
  91 #ifdef CONFIG_STACKTRACE
  92         struct           stack_trace stacktrace;
  93         unsigned long    st_entries[DMA_DEBUG_STACKTRACE_ENTRIES];
  94 #endif
  95 };
  96
  97 typedef bool (*match_fn)(struct dma_debug_entry *, struct dma_debug_entry *);
  98
  99 struct hash_bucket {
 100         struct list_head list;
 101         spinlock_t lock;
 102 } ____cacheline_aligned_in_smp;
 103
 104 /* Hash list to save the allocated dma addresses */
 105 static struct hash_bucket dma_entry_hash[HASH_SIZE];
 106 /* List of pre-allocated dma_debug_entry's */
 107 static LIST_HEAD(free_entries);
 108 /* Lock for the list above */
 109 static DEFINE_SPINLOCK(free_entries_lock);
 110
 111 /* Global disable flag - will be set in case of an error */
 112 static bool global_disable __read_mostly;
 113
 114 /* Early initialization disable flag, set at the end of dma_debug_init */
 115 static bool dma_debug_initialized __read_mostly;
 116
 117 static inline bool dma_debug_disabled(void)
 118 {
 119         return global_disable || !dma_debug_initialized;
 120 }
 121
 122 /* Global error count */
 123 static u32 error_count;
 124
 125 /* Global error show enable*/
 126 static u32 show_all_errors __read_mostly;
 127 /* Number of errors to show */
 128 static u32 show_num_errors = 1;
 129
 130 static u32 num_free_entries;
 131 static u32 min_free_entries;
 132 static u32 nr_total_entries;
 133
 134 /* number of preallocated entries requested by kernel cmdline */
 135 static u32 nr_prealloc_entries = PREALLOC_DMA_DEBUG_ENTRIES;
 136
 137 /* debugfs dentry's for the stuff above */
 138 static struct dentry *dma_debug_dent        __read_mostly;
 139 static struct dentry *global_disable_dent   __read_mostly;
 140 static struct dentry *error_count_dent      __read_mostly;
 141 static struct dentry *show_all_errors_dent  __read_mostly;
 142 static struct dentry *show_num_errors_dent  __read_mostly;
 143 static struct dentry *num_free_entries_dent __read_mostly;
 144 static struct dentry *min_free_entries_dent __read_mostly;
 145 static struct dentry *filter_dent           __read_mostly;
 146
 147 /* per-driver filter related state */
 148
 149 #define NAME_MAX_LEN    64
 150
 151 static char                  current_driver_name[NAME_MAX_LEN] __read_mostly;
 152 static struct device_driver *current_driver                    __read_mostly;
 153
 154 static DEFINE_RWLOCK(driver_name_lock);
 155
 156 static const char *const maperr2str[] = {
 157         [MAP_ERR_CHECK_NOT_APPLICABLE] = "dma map error check not applicable",
 158         [MAP_ERR_NOT_CHECKED] = "dma map error not checked",
 159         [MAP_ERR_CHECKED] = "dma map error checked",
 160 };
 161
 162 static const char *type2name[5] = { "single", "page",
 163                                     "scather-gather", "coherent",
 164                                     "resource" };
 165
 166 static const char *dir2name[4] = { "DMA_BIDIRECTIONAL", "DMA_TO_DEVICE",
 167                                    "DMA_FROM_DEVICE", "DMA_NONE" };
 168
 169 /*
 170  * The access to some variables in this macro is racy. We can't use atomic_t
 171  * here because all these variables are exported to debugfs. Some of them even
 172  * writeable. This is also the reason why a lock won't help much. But anyway,
 173  * the races are no big deal. Here is why:
 174  *
 175  *   error_count: the addition is racy, but the worst thing that can happen is
 176  *                that we don't count some errors
 177  *   show_num_errors: the subtraction is racy. Also no big deal because in
 178  *                    worst case this will result in one warning more in the
 179  *                    system log than the user configured. This variable is
 180  *                    writeable via debugfs.
 181  */
 182 static inline void dump_entry_trace(struct dma_debug_entry *entry)
 183 {
 184 #ifdef CONFIG_STACKTRACE
 185         if (entry) {
 186                 pr_warning("Mapped at:\n");
 187                 print_stack_trace(&entry->stacktrace, 0);
 188         }
 189 #endif
 190 }
 191
 192 static bool driver_filter(struct device *dev)
 193 {
 194         struct device_driver *drv;
 195         unsigned long flags;
 196         bool ret;
 197
 198         /* driver filter off */
 199         if (likely(!current_driver_name[0]))
 200                 return true;
 201
 202         /* driver filter on and initialized */
 203         if (current_driver && dev && dev->driver == current_driver)
 204                 return true;
 205
 206         /* driver filter on, but we can't filter on a NULL device... */
 207         if (!dev)
 208                 return false;
 209
 210         if (current_driver || !current_driver_name[0])
 211                 return false;
 212
 213         /* driver filter on but not yet initialized */
 214         drv = dev->driver;
 215         if (!drv)
 216                 return false;
 217
 218         /* lock to protect against change of current_driver_name */
 219         read_lock_irqsave(&driver_name_lock, flags);
 220
 221         ret = false;
 222         if (drv->name &&
 223             strncmp(current_driver_name, drv->name, NAME_MAX_LEN - 1) == 0) {
 224                 current_driver = drv;
 225                 ret = true;
 226         }
 227
 228         read_unlock_irqrestore(&driver_name_lock, flags);
 229
 230         return ret;
 231 }
 232
 233 #define err_printk(dev, entry, format, arg...) do {                     \
 234                 error_count += 1;                                       \
 235                 if (driver_filter(dev) &&                               \
 236                     (show_all_errors || show_num_errors > 0)) {         \
 237                         WARN(1, "%s %s: " format,                       \
 238                              dev ? dev_driver_string(dev) : "NULL",     \
 239                              dev ? dev_name(dev) : "NULL", ## arg);     \
 240                         dump_entry_trace(entry);                        \
 241                 }                                                       \
 242                 if (!show_all_errors && show_num_errors > 0)            \
 243                         show_num_errors -= 1;                           \
 244         } while (0);
 245
 246 /*
 247  * Hash related functions
 248  *
 249  * Every DMA-API request is saved into a struct dma_debug_entry. To
 250  * have quick access to these structs they are stored into a hash.
 251  */
 252 static int hash_fn(struct dma_debug_entry *entry)
 253 {
 254         /*
 255          * Hash function is based on the dma address.
 256          * We use bits 20-27 here as the index into the hash
 257          */
 258         return (entry->dev_addr >> HASH_FN_SHIFT) & HASH_FN_MASK;
 259 }
 260
 261 /*
 262  * Request exclusive access to a hash bucket for a given dma_debug_entry.
 263  */
 264 static struct hash_bucket *get_hash_bucket(struct dma_debug_entry *entry,
 265                                            unsigned long *flags)
 266         __acquires(&dma_entry_hash[idx].lock)
 267 {
 268         int idx = hash_fn(entry);
 269         unsigned long __flags;
 270
 271         spin_lock_irqsave(&dma_entry_hash[idx].lock, __flags);
 272         *flags = __flags;
 273         return &dma_entry_hash[idx];
 274 }
 275
 276 /*
 277  * Give up exclusive access to the hash bucket
 278  */
 279 static void put_hash_bucket(struct hash_bucket *bucket,
 280                             unsigned long *flags)
 281         __releases(&bucket->lock)
 282 {
 283         unsigned long __flags = *flags;
 284
 285         spin_unlock_irqrestore(&bucket->lock, __flags);
 286 }
 287
 288 static bool exact_match(struct dma_debug_entry *a, struct dma_debug_entry *b)
 289 {
 290         return ((a->dev_addr == b->dev_addr) &&
 291                 (a->dev == b->dev)) ? true : false;
 292 }
 293
 294 static bool containing_match(struct dma_debug_entry *a,
 295                              struct dma_debug_entry *b)
 296 {
 297         if (a->dev != b->dev)
 298                 return false;
 299
 300         if ((b->dev_addr <= a->dev_addr) &&
 301             ((b->dev_addr + b->size) >= (a->dev_addr + a->size)))
 302                 return true;
 303
 304         return false;
 305 }
 306
 307 /*
 308  * Search a given entry in the hash bucket list
 309  */
 310 static struct dma_debug_entry *__hash_bucket_find(struct hash_bucket *bucket,
 311                                                   struct dma_debug_entry *ref,
 312                                                   match_fn match)
 313 {
 314         struct dma_debug_entry *entry, *ret = NULL;
 315         int matches = 0, match_lvl, last_lvl = -1;
 316
 317         list_for_each_entry(entry, &bucket->list, list) {
 318                 if (!match(ref, entry))
 319                         continue;
 320
 321                 /*
 322                  * Some drivers map the same physical address multiple
 323                  * times. Without a hardware IOMMU this results in the
 324                  * same device addresses being put into the dma-debug
 325                  * hash multiple times too. This can result in false
 326                  * positives being reported. Therefore we implement a
 327                  * best-fit algorithm here which returns the entry from
 328                  * the hash which fits best to the reference value
 329                  * instead of the first-fit.
 330                  */
 331                 matches += 1;
 332                 match_lvl = 0;
 333                 entry->size         == ref->size         ? ++match_lvl : 0;
 334                 entry->type         == ref->type         ? ++match_lvl : 0;
 335                 entry->direction    == ref->direction    ? ++match_lvl : 0;
 336                 entry->sg_call_ents == ref->sg_call_ents ? ++match_lvl : 0;
 337
 338                 if (match_lvl == 4) {
 339                         /* perfect-fit - return the result */
 340                         return entry;
 341                 } else if (match_lvl > last_lvl) {
 342                         /*
 343                          * We found an entry that fits better then the
 344                          * previous one or it is the 1st match.
 345                          */
 346                         last_lvl = match_lvl;
 347                         ret      = entry;
 348                 }
 349         }
 350
 351         /*
 352          * If we have multiple matches but no perfect-fit, just return
 353          * NULL.
 354          */
 355         ret = (matches == 1) ? ret : NULL;
 356
 357         return ret;
 358 }
 359
 360 static struct dma_debug_entry *bucket_find_exact(struct hash_bucket *bucket,
 361                                                  struct dma_debug_entry *ref)
 362 {
 363         return __hash_bucket_find(bucket, ref, exact_match);
 364 }
 365
 366 static struct dma_debug_entry *bucket_find_contain(struct hash_bucket **bucket,
 367                                                    struct dma_debug_entry *ref,
 368                                                    unsigned long *flags)
 369 {
 370
 371         unsigned int max_range = dma_get_max_seg_size(ref->dev);
 372         struct dma_debug_entry *entry, index = *ref;
 373         unsigned int range = 0;
 374
 375         while (range <= max_range) {
 376                 entry = __hash_bucket_find(*bucket, ref, containing_match);
 377
 378                 if (entry)
 379                         return entry;
 380
 381                 /*
 382                  * Nothing found, go back a hash bucket
 383                  */
 384                 put_hash_bucket(*bucket, flags);
 385                 range          += (1 << HASH_FN_SHIFT);
 386                 index.dev_addr -= (1 << HASH_FN_SHIFT);
 387                 *bucket = get_hash_bucket(&index, flags);
 388         }
 389
 390         return NULL;
 391 }
 392
 393 /*
 394  * Add an entry to a hash bucket
 395  */
 396 static void hash_bucket_add(struct hash_bucket *bucket,
 397                             struct dma_debug_entry *entry)
 398 {
 399         list_add_tail(&entry->list, &bucket->list);
 400 }
 401
 402 /*
 403  * Remove entry from a hash bucket list
 404  */
 405 static void hash_bucket_del(struct dma_debug_entry *entry)
 406 {
 407         list_del(&entry->list);
 408 }
 409
 410 static unsigned long long phys_addr(struct dma_debug_entry *entry)
 411 {
 412         if (entry->type == dma_debug_resource)
 413                 return __pfn_to_phys(entry->pfn) + entry->offset;
 414
 415         return page_to_phys(pfn_to_page(entry->pfn)) + entry->offset;
 416 }
 417
 418 /*
 419  * Dump mapping entries for debugging purposes
 420  */
 421 void debug_dma_dump_mappings(struct device *dev)
 422 {
 423         int idx;
 424
 425         for (idx = 0; idx < HASH_SIZE; idx++) {
 426                 struct hash_bucket *bucket = &dma_entry_hash[idx];
 427                 struct dma_debug_entry *entry;
 428                 unsigned long flags;
 429
 430                 spin_lock_irqsave(&bucket->lock, flags);
 431
 432                 list_for_each_entry(entry, &bucket->list, list) {
 433                         if (!dev || dev == entry->dev) {
 434                                 dev_info(entry->dev,
 435                                          "%s idx %d P=%Lx N=%lx D=%Lx L=%Lx %s %s\n",
 436                                          type2name[entry->type], idx,
 437                                          phys_addr(entry), entry->pfn,
 438                                          entry->dev_addr, entry->size,
 439                                          dir2name[entry->direction],
 440                                          maperr2str[entry->map_err_type]);
 441                         }
 442                 }
 443
 444                 spin_unlock_irqrestore(&bucket->lock, flags);
 445         }
 446 }
 447
 448 /*
 449  * For each mapping (initial cacheline in the case of
 450  * dma_alloc_coherent/dma_map_page, initial cacheline in each page of a
 451  * scatterlist, or the cacheline specified in dma_map_single) insert
 452  * into this tree using the cacheline as the key. At
 453  * dma_unmap_{single|sg|page} or dma_free_coherent delete the entry.  If
 454  * the entry already exists at insertion time add a tag as a reference
 455  * count for the overlapping mappings.  For now, the overlap tracking
 456  * just ensures that 'unmaps' balance 'maps' before marking the
 457  * cacheline idle, but we should also be flagging overlaps as an API
 458  * violation.
 459  *
 460  * Memory usage is mostly constrained by the maximum number of available
 461  * dma-debug entries in that we need a free dma_debug_entry before
 462  * inserting into the tree.  In the case of dma_map_page and
 463  * dma_alloc_coherent there is only one dma_debug_entry and one
 464  * dma_active_cacheline entry to track per event.  dma_map_sg(), on the
 465  * other hand, consumes a single dma_debug_entry, but inserts 'nents'
 466  * entries into the tree.
 467  *
 468  * At any time debug_dma_assert_idle() can be called to trigger a
 469  * warning if any cachelines in the given page are in the active set.
 470  */
 471 static RADIX_TREE(dma_active_cacheline, GFP_NOWAIT);
 472 static DEFINE_SPINLOCK(radix_lock);
 473 #define ACTIVE_CACHELINE_MAX_OVERLAP ((1 << RADIX_TREE_MAX_TAGS) - 1)
 474 #define CACHELINE_PER_PAGE_SHIFT (PAGE_SHIFT - L1_CACHE_SHIFT)
 475 #define CACHELINES_PER_PAGE (1 << CACHELINE_PER_PAGE_SHIFT)
 476
 477 static phys_addr_t to_cacheline_number(struct dma_debug_entry *entry)
 478 {
 479         return (entry->pfn << CACHELINE_PER_PAGE_SHIFT) +
 480                 (entry->offset >> L1_CACHE_SHIFT);
 481 }
 482
 483 static int active_cacheline_read_overlap(phys_addr_t cln)
 484 {
 485         int overlap = 0, i;
 486
 487         for (i = RADIX_TREE_MAX_TAGS - 1; i >= 0; i--)
 488                 if (radix_tree_tag_get(&dma_active_cacheline, cln, i))
 489                         overlap |= 1 << i;
 490         return overlap;
 491 }
 492
 493 static int active_cacheline_set_overlap(phys_addr_t cln, int overlap)
 494 {
 495         int i;
 496
 497         if (overlap > ACTIVE_CACHELINE_MAX_OVERLAP || overlap < 0)
 498                 return overlap;
 499
 500         for (i = RADIX_TREE_MAX_TAGS - 1; i >= 0; i--)
 501                 if (overlap & 1 << i)
 502                         radix_tree_tag_set(&dma_active_cacheline, cln, i);
 503                 else
 504                         radix_tree_tag_clear(&dma_active_cacheline, cln, i);
 505
 506         return overlap;
 507 }
 508
 509 static void active_cacheline_inc_overlap(phys_addr_t cln)
 510 {
 511         int overlap = active_cacheline_read_overlap(cln);
 512
 513         overlap = active_cacheline_set_overlap(cln, ++overlap);
 514
 515         /* If we overflowed the overlap counter then we're potentially
 516          * leaking dma-mappings.  Otherwise, if maps and unmaps are
 517          * balanced then this overflow may cause false negatives in
 518          * debug_dma_assert_idle() as the cacheline may be marked idle
 519          * prematurely.
 520          */
 521         WARN_ONCE(overlap > ACTIVE_CACHELINE_MAX_OVERLAP,
 522                   "DMA-API: exceeded %d overlapping mappings of cacheline %pa\n",
 523                   ACTIVE_CACHELINE_MAX_OVERLAP, &cln);
 524 }
 525
 526 static int active_cacheline_dec_overlap(phys_addr_t cln)
 527 {
 528         int overlap = active_cacheline_read_overlap(cln);
 529
 530         return active_cacheline_set_overlap(cln, --overlap);
 531 }
 532
 533 static int active_cacheline_insert(struct dma_debug_entry *entry)
 534 {
 535         phys_addr_t cln = to_cacheline_number(entry);
 536         unsigned long flags;
 537         int rc;
 538
 539         /* If the device is not writing memory then we don't have any
 540          * concerns about the cpu consuming stale data.  This mitigates
 541          * legitimate usages of overlapping mappings.
 542          */
 543         if (entry->direction == DMA_TO_DEVICE)
 544                 return 0;
 545
 546         spin_lock_irqsave(&radix_lock, flags);
 547         rc = radix_tree_insert(&dma_active_cacheline, cln, entry);
 548         if (rc == -EEXIST)
 549                 active_cacheline_inc_overlap(cln);
 550         spin_unlock_irqrestore(&radix_lock, flags);
 551
 552         return rc;
 553 }
 554
 555 static void active_cacheline_remove(struct dma_debug_entry *entry)
 556 {
 557         phys_addr_t cln = to_cacheline_number(entry);
 558         unsigned long flags;
 559
 560         /* ...mirror the insert case */
 561         if (entry->direction == DMA_TO_DEVICE)
 562                 return;
 563
 564         spin_lock_irqsave(&radix_lock, flags);
 565         /* since we are counting overlaps the final put of the
 566          * cacheline will occur when the overlap count is 0.
 567          * active_cacheline_dec_overlap() returns -1 in that case
 568          */
 569         if (active_cacheline_dec_overlap(cln) < 0)
 570                 radix_tree_delete(&dma_active_cacheline, cln);
 571         spin_unlock_irqrestore(&radix_lock, flags);
 572 }
 573
 574 /**
 575  * debug_dma_assert_idle() - assert that a page is not undergoing dma
 576  * @page: page to lookup in the dma_active_cacheline tree
 577  *
 578  * Place a call to this routine in cases where the cpu touching the page
 579  * before the dma completes (page is dma_unmapped) will lead to data
 580  * corruption.
 581  */
 582 void debug_dma_assert_idle(struct page *page)
 583 {
 584         static struct dma_debug_entry *ents[CACHELINES_PER_PAGE];
 585         struct dma_debug_entry *entry = NULL;
 586         void **results = (void **) &ents;
 587         unsigned int nents, i;
 588         unsigned long flags;
 589         phys_addr_t cln;
 590
 591         if (dma_debug_disabled())
 592                 return;
 593
 594         if (!page)
 595                 return;
 596
 597         cln = (phys_addr_t) page_to_pfn(page) << CACHELINE_PER_PAGE_SHIFT;
 598         spin_lock_irqsave(&radix_lock, flags);
 599         nents = radix_tree_gang_lookup(&dma_active_cacheline, results, cln,
 600                                        CACHELINES_PER_PAGE);
 601         for (i = 0; i < nents; i++) {
 602                 phys_addr_t ent_cln = to_cacheline_number(ents[i]);
 603
 604                 if (ent_cln == cln) {
 605                         entry = ents[i];
 606                         break;
 607                 } else if (ent_cln >= cln + CACHELINES_PER_PAGE)
 608                         break;
 609         }
 610         spin_unlock_irqrestore(&radix_lock, flags);
 611
 612         if (!entry)
 613                 return;
 614
 615         cln = to_cacheline_number(entry);
 616         err_printk(entry->dev, entry,
 617                    "DMA-API: cpu touching an active dma mapped cacheline [cln=%pa]\n",
 618                    &cln);
 619 }
 620
 621 /*
 622  * Wrapper function for adding an entry to the hash.
 623  * This function takes care of locking itself.
 624  */
 625 static void add_dma_entry(struct dma_debug_entry *entry)
 626 {
 627         struct hash_bucket *bucket;
 628         unsigned long flags;
 629         int rc;
 630
 631         bucket = get_hash_bucket(entry, &flags);
 632         hash_bucket_add(bucket, entry);
 633         put_hash_bucket(bucket, &flags);
 634
 635         rc = active_cacheline_insert(entry);
 636         if (rc == -ENOMEM) {
 637                 pr_err("DMA-API: cacheline tracking ENOMEM, dma-debug disabled\n");
 638                 global_disable = true;
 639         }
 640
 641         /* TODO: report -EEXIST errors here as overlapping mappings are
 642          * not supported by the DMA API
 643          */
 644 }
 645
 646 static struct dma_debug_entry *__dma_entry_alloc(void)
 647 {
 648         struct dma_debug_entry *entry;
 649
 650         entry = list_entry(free_entries.next, struct dma_debug_entry, list);
 651         list_del(&entry->list);
 652         memset(entry, 0, sizeof(*entry));
 653
 654         num_free_entries -= 1;
 655         if (num_free_entries < min_free_entries)
 656                 min_free_entries = num_free_entries;
 657
 658         return entry;
 659 }
 660
 661 /* struct dma_entry allocator
 662  *
 663  * The next two functions implement the allocator for
 664  * struct dma_debug_entries.
 665  */
 666 static struct dma_debug_entry *dma_entry_alloc(void)
 667 {
 668         struct dma_debug_entry *entry;
 669         unsigned long flags;
 670
 671         spin_lock_irqsave(&free_entries_lock, flags);
 672
 673         if (list_empty(&free_entries)) {
 674                 global_disable = true;
 675                 spin_unlock_irqrestore(&free_entries_lock, flags);
 676                 pr_err("DMA-API: debugging out of memory - disabling\n");
 677                 return NULL;
 678         }
 679
 680         entry = __dma_entry_alloc();
 681
 682         spin_unlock_irqrestore(&free_entries_lock, flags);
 683
 684 #ifdef CONFIG_STACKTRACE
 685         entry->stacktrace.max_entries = DMA_DEBUG_STACKTRACE_ENTRIES;
 686         entry->stacktrace.entries = entry->st_entries;
 687         entry->stacktrace.skip = 2;
 688         save_stack_trace(&entry->stacktrace);
 689 #endif
 690
 691         return entry;
 692 }
 693
 694 static void dma_entry_free(struct dma_debug_entry *entry)
 695 {
 696         unsigned long flags;
 697
 698         active_cacheline_remove(entry);
 699
 700         /*
 701          * add to beginning of the list - this way the entries are
 702          * more likely cache hot when they are reallocated.
 703          */
 704         spin_lock_irqsave(&free_entries_lock, flags);
 705         list_add(&entry->list, &free_entries);
 706         num_free_entries += 1;
 707         spin_unlock_irqrestore(&free_entries_lock, flags);
 708 }
 709
 710 int dma_debug_resize_entries(u32 num_entries)
 711 {
 712         int i, delta, ret = 0;
 713         unsigned long flags;
 714         struct dma_debug_entry *entry;
 715         LIST_HEAD(tmp);
 716
 717         spin_lock_irqsave(&free_entries_lock, flags);
 718
 719         if (nr_total_entries < num_entries) {
 720                 delta = num_entries - nr_total_entries;
 721
 722                 spin_unlock_irqrestore(&free_entries_lock, flags);
 723
 724                 for (i = 0; i < delta; i++) {
 725                         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 726                         if (!entry)
 727                                 break;
 728
 729                         list_add_tail(&entry->list, &tmp);
 730                 }
 731
 732                 spin_lock_irqsave(&free_entries_lock, flags);
 733
 734                 list_splice(&tmp, &free_entries);
 735                 nr_total_entries += i;
 736                 num_free_entries += i;
 737         } else {
 738                 delta = nr_total_entries - num_entries;
 739
 740                 for (i = 0; i < delta && !list_empty(&free_entries); i++) {
 741                         entry = __dma_entry_alloc();
 742                         kfree(entry);
 743                 }
 744
 745                 nr_total_entries -= i;
 746         }
 747
 748         if (nr_total_entries != num_entries)
 749                 ret = 1;
 750
 751         spin_unlock_irqrestore(&free_entries_lock, flags);
 752
 753         return ret;
 754 }
 755
 756 /*
 757  * DMA-API debugging init code
 758  *
 759  * The init code does two things:
 760  *   1. Initialize core data structures
 761  *   2. Preallocate a given number of dma_debug_entry structs
 762  */
 763
 764 static int prealloc_memory(u32 num_entries)
 765 {
 766         struct dma_debug_entry *entry, *next_entry;
 767         int i;
 768
 769         for (i = 0; i < num_entries; ++i) {
 770                 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 771                 if (!entry)
 772                         goto out_err;
 773
 774                 list_add_tail(&entry->list, &free_entries);
 775         }
 776
 777         num_free_entries = num_entries;
 778         min_free_entries = num_entries;
 779
 780         pr_info("DMA-API: preallocated %d debug entries\n", num_entries);
 781
 782         return 0;
 783
 784 out_err:
 785
 786         list_for_each_entry_safe(entry, next_entry, &free_entries, list) {
 787                 list_del(&entry->list);
 788                 kfree(entry);
 789         }
 790
 791         return -ENOMEM;
 792 }
 793
 794 static ssize_t filter_read(struct file *file, char __user *user_buf,
 795                            size_t count, loff_t *ppos)
 796 {
 797         char buf[NAME_MAX_LEN + 1];
 798         unsigned long flags;
 799         int len;
 800
 801         if (!current_driver_name[0])
 802                 return 0;
 803
 804         /*
 805          * We can't copy to userspace directly because current_driver_name can
 806          * only be read under the driver_name_lock with irqs disabled. So
 807          * create a temporary copy first.
 808          */
 809         read_lock_irqsave(&driver_name_lock, flags);
 810         len = scnprintf(buf, NAME_MAX_LEN + 1, "%s\n", current_driver_name);
 811         read_unlock_irqrestore(&driver_name_lock, flags);
 812
 813         return simple_read_from_buffer(user_buf, count, ppos, buf, len);
 814 }
 815
 816 static ssize_t filter_write(struct file *file, const char __user *userbuf,
 817                             size_t count, loff_t *ppos)
 818 {
 819         char buf[NAME_MAX_LEN];
 820         unsigned long flags;
 821         size_t len;
 822         int i;
 823
 824         /*
 825          * We can't copy from userspace directly. Access to
 826          * current_driver_name is protected with a write_lock with irqs
 827          * disabled. Since copy_from_user can fault and may sleep we
 828          * need to copy to temporary buffer first
 829          */
 830         len = min(count, (size_t)(NAME_MAX_LEN - 1));
 831         if (copy_from_user(buf, userbuf, len))
 832                 return -EFAULT;
 833
 834         buf[len] = 0;
 835
 836         write_lock_irqsave(&driver_name_lock, flags);
 837
 838         /*
 839          * Now handle the string we got from userspace very carefully.
 840          * The rules are:
 841          *         - only use the first token we got
 842          *         - token delimiter is everything looking like a space
 843          *           character (' ', '\n', '\t' ...)
 844          *
 845          */
 846         if (!isalnum(buf[0])) {
 847                 /*
 848                  * If the first character userspace gave us is not
 849                  * alphanumerical then assume the filter should be
 850                  * switched off.
 851                  */
 852                 if (current_driver_name[0])
 853                         pr_info("DMA-API: switching off dma-debug driver filter\n");
 854                 current_driver_name[0] = 0;
 855                 current_driver = NULL;
 856                 goto out_unlock;
 857         }
 858
 859         /*
 860          * Now parse out the first token and use it as the name for the
 861          * driver to filter for.
 862          */
 863         for (i = 0; i < NAME_MAX_LEN - 1; ++i) {
 864                 current_driver_name[i] = buf[i];
 865                 if (isspace(buf[i]) || buf[i] == ' ' || buf[i] == 0)
 866                         break;
 867         }
 868         current_driver_name[i] = 0;
 869         current_driver = NULL;
 870
 871         pr_info("DMA-API: enable driver filter for driver [%s]\n",
 872                 current_driver_name);
 873
 874 out_unlock:
 875         write_unlock_irqrestore(&driver_name_lock, flags);
 876
 877         return count;
 878 }
 879
 880 static const struct file_operations filter_fops = {
 881         .read  = filter_read,
 882         .write = filter_write,
 883         .llseek = default_llseek,
 884 };
 885
 886 static int dma_debug_fs_init(void)
 887 {
 888         dma_debug_dent = debugfs_create_dir("dma-api", NULL);
 889         if (!dma_debug_dent) {
 890                 pr_err("DMA-API: can not create debugfs directory\n");
 891                 return -ENOMEM;
 892         }
 893
 894         global_disable_dent = debugfs_create_bool("disabled", 0444,
 895                         dma_debug_dent,
 896                         &global_disable);
 897         if (!global_disable_dent)
 898                 goto out_err;
 899
 900         error_count_dent = debugfs_create_u32("error_count", 0444,
 901                         dma_debug_dent, &error_count);
 902         if (!error_count_dent)
 903                 goto out_err;
 904
 905         show_all_errors_dent = debugfs_create_u32("all_errors", 0644,
 906                         dma_debug_dent,
 907                         &show_all_errors);
 908         if (!show_all_errors_dent)
 909                 goto out_err;
 910
 911         show_num_errors_dent = debugfs_create_u32("num_errors", 0644,
 912                         dma_debug_dent,
 913                         &show_num_errors);
 914         if (!show_num_errors_dent)
 915                 goto out_err;
 916
 917         num_free_entries_dent = debugfs_create_u32("num_free_entries", 0444,
 918                         dma_debug_dent,
 919                         &num_free_entries);
 920         if (!num_free_entries_dent)
 921                 goto out_err;
 922
 923         min_free_entries_dent = debugfs_create_u32("min_free_entries", 0444,
 924                         dma_debug_dent,
 925                         &min_free_entries);
 926         if (!min_free_entries_dent)
 927                 goto out_err;
 928
 929         filter_dent = debugfs_create_file("driver_filter", 0644,
 930                                           dma_debug_dent, NULL, &filter_fops);
 931         if (!filter_dent)
 932                 goto out_err;
 933
 934         return 0;
 935
 936 out_err:
 937         debugfs_remove_recursive(dma_debug_dent);
 938
 939         return -ENOMEM;
 940 }
 941
 942 static int device_dma_allocations(struct device *dev, struct dma_debug_entry **out_entry)
 943 {
 944         struct dma_debug_entry *entry;
 945         unsigned long flags;
 946         int count = 0, i;
 947
 948         for (i = 0; i < HASH_SIZE; ++i) {
 949                 spin_lock_irqsave(&dma_entry_hash[i].lock, flags);
 950                 list_for_each_entry(entry, &dma_entry_hash[i].list, list) {
 951                         if (entry->dev == dev) {
 952                                 count += 1;
 953                                 *out_entry = entry;
 954                         }
 955                 }
 956                 spin_unlock_irqrestore(&dma_entry_hash[i].lock, flags);
 957         }
 958
 959         return count;
 960 }
 961
 962 static int dma_debug_device_change(struct notifier_block *nb, unsigned long action, void *data)
 963 {
 964         struct device *dev = data;
 965         struct dma_debug_entry *uninitialized_var(entry);
 966         int count;
 967
 968         if (dma_debug_disabled())
 969                 return 0;
 970
 971         switch (action) {
 972         case BUS_NOTIFY_UNBOUND_DRIVER:
 973                 count = device_dma_allocations(dev, &entry);
 974                 if (count == 0)
 975                         break;
 976                 err_printk(dev, entry, "DMA-API: device driver has pending "
 977                                 "DMA allocations while released from device "
 978                                 "[count=%d]\n"
 979                                 "One of leaked entries details: "
 980                                 "[device address=0x%016llx] [size=%llu bytes] "
 981                                 "[mapped with %s] [mapped as %s]\n",
 982                         count, entry->dev_addr, entry->size,
 983                         dir2name[entry->direction], type2name[entry->type]);
 984                 break;
 985         default:
 986                 break;
 987         }
 988
 989         return 0;
 990 }
 991
 992 void dma_debug_add_bus(struct bus_type *bus)
 993 {
 994         struct notifier_block *nb;
 995
 996         if (dma_debug_disabled())
 997                 return;
 998
 999         nb = kzalloc(sizeof(struct notifier_block), GFP_KERNEL);
1000         if (nb == NULL) {
1001                 pr_err("dma_debug_add_bus: out of memory\n");
1002                 return;
1003         }
1004
1005         nb->notifier_call = dma_debug_device_change;
1006
1007         bus_register_notifier(bus, nb);
1008 }
1009
1010 static int dma_debug_init(void)
1011 {
1012         int i;
1013
1014         /* Do not use dma_debug_initialized here, since we really want to be
1015          * called to set dma_debug_initialized
1016          */
1017         if (global_disable)
1018                 return 0;
1019
1020         for (i = 0; i < HASH_SIZE; ++i) {
1021                 INIT_LIST_HEAD(&dma_entry_hash[i].list);
1022                 spin_lock_init(&dma_entry_hash[i].lock);
1023         }
1024
1025         if (dma_debug_fs_init() != 0) {
1026                 pr_err("DMA-API: error creating debugfs entries - disabling\n");
1027                 global_disable = true;
1028
1029                 return 0;
1030         }
1031
1032         if (prealloc_memory(nr_prealloc_entries) != 0) {
1033                 pr_err("DMA-API: debugging out of memory error - disabled\n");
1034                 global_disable = true;
1035
1036                 return 0;
1037         }
1038
1039         nr_total_entries = num_free_entries;
1040
1041         dma_debug_initialized = true;
1042
1043         pr_info("DMA-API: debugging enabled by kernel config\n");
1044         return 0;
1045 }
1046 core_initcall(dma_debug_init);
1047
1048 static __init int dma_debug_cmdline(char *str)
1049 {
1050         if (!str)
1051                 return -EINVAL;
1052
1053         if (strncmp(str, "off", 3) == 0) {
1054                 pr_info("DMA-API: debugging disabled on kernel command line\n");
1055                 global_disable = true;
1056         }
1057
1058         return 0;
1059 }
1060
1061 static __init int dma_debug_entries_cmdline(char *str)
1062 {
1063         if (!str)
1064                 return -EINVAL;
1065         if (!get_option(&str, &nr_prealloc_entries))
1066                 nr_prealloc_entries = PREALLOC_DMA_DEBUG_ENTRIES;
1067         return 0;
1068 }
1069
1070 __setup("dma_debug=", dma_debug_cmdline);
1071 __setup("dma_debug_entries=", dma_debug_entries_cmdline);
1072
1073 static void check_unmap(struct dma_debug_entry *ref)
1074 {
1075         struct dma_debug_entry *entry;
1076         struct hash_bucket *bucket;
1077         unsigned long flags;
1078
1079         bucket = get_hash_bucket(ref, &flags);
1080         entry = bucket_find_exact(bucket, ref);
1081
1082         if (!entry) {
1083                 /* must drop lock before calling dma_mapping_error */
1084                 put_hash_bucket(bucket, &flags);
1085
1086                 if (dma_mapping_error(ref->dev, ref->dev_addr)) {
1087                         err_printk(ref->dev, NULL,
1088                                    "DMA-API: device driver tries to free an "
1089                                    "invalid DMA memory address\n");
1090                 } else {
1091                         err_printk(ref->dev, NULL,
1092                                    "DMA-API: device driver tries to free DMA "
1093                                    "memory it has not allocated [device "
1094                                    "address=0x%016llx] [size=%llu bytes]\n",
1095                                    ref->dev_addr, ref->size);
1096                 }
1097                 return;
1098         }
1099
1100         if (ref->size != entry->size) {
1101                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
1102                            "DMA memory with different size "
1103                            "[device address=0x%016llx] [map size=%llu bytes] "
1104                            "[unmap size=%llu bytes]\n",
1105                            ref->dev_addr, entry->size, ref->size);
1106         }
1107
1108         if (ref->type != entry->type) {
1109                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
1110                            "DMA memory with wrong function "
1111                            "[device address=0x%016llx] [size=%llu bytes] "
1112                            "[mapped as %s] [unmapped as %s]\n",
1113                            ref->dev_addr, ref->size,
1114                            type2name[entry->type], type2name[ref->type]);
1115         } else if ((entry->type == dma_debug_coherent) &&
1116                    (phys_addr(ref) != phys_addr(entry))) {
1117                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
1118                            "DMA memory with different CPU address "
1119                            "[device address=0x%016llx] [size=%llu bytes] "
1120                            "[cpu alloc address=0x%016llx] "
1121                            "[cpu free address=0x%016llx]",
1122                            ref->dev_addr, ref->size,
1123                            phys_addr(entry),
1124                            phys_addr(ref));
1125         }
1126
1127         if (ref->sg_call_ents && ref->type == dma_debug_sg &&
1128             ref->sg_call_ents != entry->sg_call_ents) {
1129                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
1130                            "DMA sg list with different entry count "
1131                            "[map count=%d] [unmap count=%d]\n",
1132                            entry->sg_call_ents, ref->sg_call_ents);
1133         }
1134
1135         /*
1136          * This may be no bug in reality - but most implementations of the
1137          * DMA API don't handle this properly, so check for it here
1138          */
1139         if (ref->direction != entry->direction) {
1140                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
1141                            "DMA memory with different direction "
1142                            "[device address=0x%016llx] [size=%llu bytes] "
1143                            "[mapped with %s] [unmapped with %s]\n",
1144                            ref->dev_addr, ref->size,
1145                            dir2name[entry->direction],
1146                            dir2name[ref->direction]);
1147         }
1148
1149         /*
1150          * Drivers should use dma_mapping_error() to check the returned
1151          * addresses of dma_map_single() and dma_map_page().
1152          * If not, print this warning message. See Documentation/DMA-API.txt.
1153          */
1154         if (entry->map_err_type == MAP_ERR_NOT_CHECKED) {
1155                 err_printk(ref->dev, entry,
1156                            "DMA-API: device driver failed to check map error"
1157                            "[device address=0x%016llx] [size=%llu bytes] "
1158                            "[mapped as %s]",
1159                            ref->dev_addr, ref->size,
1160                            type2name[entry->type]);
1161         }
1162
1163         hash_bucket_del(entry);
1164         dma_entry_free(entry);
1165
1166         put_hash_bucket(bucket, &flags);
1167 }
1168
1169 static void check_for_stack(struct device *dev,
1170                             struct page *page, size_t offset)
1171 {
1172         void *addr;
1173         struct vm_struct *stack_vm_area = task_stack_vm_area(current);
1174
1175         if (!stack_vm_area) {
1176                 /* Stack is direct-mapped. */
1177                 if (PageHighMem(page))
1178                         return;
1179                 addr = page_address(page) + offset;
1180                 if (object_is_on_stack(addr))
1181                         err_printk(dev, NULL, "DMA-API: device driver maps memory from stack [addr=%p]\n", addr);
1182         } else {
1183                 /* Stack is vmalloced. */
1184                 int i;
1185
1186                 for (i = 0; i < stack_vm_area->nr_pages; i++) {
1187                         if (page != stack_vm_area->pages[i])
1188                                 continue;
1189
1190                         addr = (u8 *)current->stack + i * PAGE_SIZE + offset;
1191                         err_printk(dev, NULL, "DMA-API: device driver maps memory from stack [probable addr=%p]\n", addr);
1192                         break;
1193                 }
1194         }
1195 }
1196
1197 static inline bool overlap(void *addr, unsigned long len, void *start, void *end)
1198 {
1199         unsigned long a1 = (unsigned long)addr;
1200         unsigned long b1 = a1 + len;
1201         unsigned long a2 = (unsigned long)start;
1202         unsigned long b2 = (unsigned long)end;
1203
1204         return !(b1 <= a2 || a1 >= b2);
1205 }
1206
1207 static void check_for_illegal_area(struct device *dev, void *addr, unsigned long len)
1208 {
1209         if (overlap(addr, len, _stext, _etext) ||
1210             overlap(addr, len, __start_rodata, __end_rodata))
1211                 err_printk(dev, NULL, "DMA-API: device driver maps memory from kernel text or rodata [addr=%p] [len=%lu]\n", addr, len);
1212 }
1213
1214 static void check_sync(struct device *dev,
1215                        struct dma_debug_entry *ref,
1216                        bool to_cpu)
1217 {
1218         struct dma_debug_entry *entry;
1219         struct hash_bucket *bucket;
1220         unsigned long flags;
1221
1222         bucket = get_hash_bucket(ref, &flags);
1223
1224         entry = bucket_find_contain(&bucket, ref, &flags);
1225
1226         if (!entry) {
1227                 err_printk(dev, NULL, "DMA-API: device driver tries "
1228                                 "to sync DMA memory it has not allocated "
1229                                 "[device address=0x%016llx] [size=%llu bytes]\n",
1230                                 (unsigned long long)ref->dev_addr, ref->size);
1231                 goto out;
1232         }
1233
1234         if (ref->size > entry->size) {
1235                 err_printk(dev, entry, "DMA-API: device driver syncs"
1236                                 " DMA memory outside allocated range "
1237                                 "[device address=0x%016llx] "
1238                                 "[allocation size=%llu bytes] "
1239                                 "[sync offset+size=%llu]\n",
1240                                 entry->dev_addr, entry->size,
1241                                 ref->size);
1242         }
1243
1244         if (entry->direction == DMA_BIDIRECTIONAL)
1245                 goto out;
1246
1247         if (ref->direction != entry->direction) {
1248                 err_printk(dev, entry, "DMA-API: device driver syncs "
1249                                 "DMA memory with different direction "
1250                                 "[device address=0x%016llx] [size=%llu bytes] "
1251                                 "[mapped with %s] [synced with %s]\n",
1252                                 (unsigned long long)ref->dev_addr, entry->size,
1253                                 dir2name[entry->direction],
1254                                 dir2name[ref->direction]);
1255         }
1256
1257         if (to_cpu && !(entry->direction == DMA_FROM_DEVICE) &&
1258                       !(ref->direction == DMA_TO_DEVICE))
1259                 err_printk(dev, entry, "DMA-API: device driver syncs "
1260                                 "device read-only DMA memory for cpu "
1261                                 "[device address=0x%016llx] [size=%llu bytes] "
1262                                 "[mapped with %s] [synced with %s]\n",
1263                                 (unsigned long long)ref->dev_addr, entry->size,
1264                                 dir2name[entry->direction],
1265                                 dir2name[ref->direction]);
1266
1267         if (!to_cpu && !(entry->direction == DMA_TO_DEVICE) &&
1268                        !(ref->direction == DMA_FROM_DEVICE))
1269                 err_printk(dev, entry, "DMA-API: device driver syncs "
1270                                 "device write-only DMA memory to device "
1271                                 "[device address=0x%016llx] [size=%llu bytes] "
1272                                 "[mapped with %s] [synced with %s]\n",
1273                                 (unsigned long long)ref->dev_addr, entry->size,
1274                                 dir2name[entry->direction],
1275                                 dir2name[ref->direction]);
1276
1277         if (ref->sg_call_ents && ref->type == dma_debug_sg &&
1278             ref->sg_call_ents != entry->sg_call_ents) {
1279                 err_printk(ref->dev, entry, "DMA-API: device driver syncs "
1280                            "DMA sg list with different entry count "
1281                            "[map count=%d] [sync count=%d]\n",
1282                            entry->sg_call_ents, ref->sg_call_ents);
1283         }
1284
1285 out:
1286         put_hash_bucket(bucket, &flags);
1287 }
1288
1289 static void check_sg_segment(struct device *dev, struct scatterlist *sg)
1290 {
1291 #ifdef CONFIG_DMA_API_DEBUG_SG
1292         unsigned int max_seg = dma_get_max_seg_size(dev);
1293         u64 start, end, boundary = dma_get_seg_boundary(dev);
1294
1295         /*
1296          * Either the driver forgot to set dma_parms appropriately, or
1297          * whoever generated the list forgot to check them.
1298          */
1299         if (sg->length > max_seg)
1300                 err_printk(dev, NULL, "DMA-API: mapping sg segment longer than device claims to support [len=%u] [max=%u]\n",
1301                            sg->length, max_seg);
1302         /*
1303          * In some cases this could potentially be the DMA API
1304          * implementation's fault, but it would usually imply that
1305          * the scatterlist was built inappropriately to begin with.
1306          */
1307         start = sg_dma_address(sg);
1308         end = start + sg_dma_len(sg) - 1;
1309         if ((start ^ end) & ~boundary)
1310                 err_printk(dev, NULL, "DMA-API: mapping sg segment across boundary [start=0x%016llx] [end=0x%016llx] [boundary=0x%016llx]\n",
1311                            start, end, boundary);
1312 #endif
1313 }
1314
1315 void debug_dma_map_single(struct device *dev, const void *addr,
1316                             unsigned long len)
1317 {
1318         if (unlikely(dma_debug_disabled()))
1319                 return;
1320
1321         if (!virt_addr_valid(addr))
1322                 err_printk(dev, NULL, "DMA-API: device driver maps memory from invalid area [addr=%p] [len=%lu]\n",
1323                            addr, len);
1324
1325         if (is_vmalloc_addr(addr))
1326                 err_printk(dev, NULL, "DMA-API: device driver maps memory from vmalloc area [addr=%p] [len=%lu]\n",
1327                            addr, len);
1328 }
1329 EXPORT_SYMBOL(debug_dma_map_single);
1330
1331 void debug_dma_map_page(struct device *dev, struct page *page, size_t offset,
1332                         size_t size, int direction, dma_addr_t dma_addr,
1333                         bool map_single)
1334 {
1335         struct dma_debug_entry *entry;
1336
1337         if (unlikely(dma_debug_disabled()))
1338                 return;
1339
1340         if (dma_mapping_error(dev, dma_addr))
1341                 return;
1342
1343         entry = dma_entry_alloc();
1344         if (!entry)
1345                 return;
1346
1347         entry->dev       = dev;
1348         entry->type      = dma_debug_page;
1349         entry->pfn       = page_to_pfn(page);
1350         entry->offset    = offset,
1351         entry->dev_addr  = dma_addr;
1352         entry->size      = size;
1353         entry->direction = direction;
1354         entry->map_err_type = MAP_ERR_NOT_CHECKED;
1355
1356         if (map_single)
1357                 entry->type = dma_debug_single;
1358
1359         check_for_stack(dev, page, offset);
1360
1361         if (!PageHighMem(page)) {
1362                 void *addr = page_address(page) + offset;
1363
1364                 check_for_illegal_area(dev, addr, size);
1365         }
1366
1367         add_dma_entry(entry);
1368 }
1369 EXPORT_SYMBOL(debug_dma_map_page);
1370
1371 void debug_dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
1372 {
1373         struct dma_debug_entry ref;
1374         struct dma_debug_entry *entry;
1375         struct hash_bucket *bucket;
1376         unsigned long flags;
1377
1378         if (unlikely(dma_debug_disabled()))
1379                 return;
1380
1381         ref.dev = dev;
1382         ref.dev_addr = dma_addr;
1383         bucket = get_hash_bucket(&ref, &flags);
1384
1385         list_for_each_entry(entry, &bucket->list, list) {
1386                 if (!exact_match(&ref, entry))
1387                         continue;
1388
1389                 /*
1390                  * The same physical address can be mapped multiple
1391                  * times. Without a hardware IOMMU this results in the
1392                  * same device addresses being put into the dma-debug
1393                  * hash multiple times too. This can result in false
1394                  * positives being reported. Therefore we implement a
1395                  * best-fit algorithm here which updates the first entry
1396                  * from the hash which fits the reference value and is
1397                  * not currently listed as being checked.
1398                  */
1399                 if (entry->map_err_type == MAP_ERR_NOT_CHECKED) {
1400                         entry->map_err_type = MAP_ERR_CHECKED;
1401                         break;
1402                 }
1403         }
1404
1405         put_hash_bucket(bucket, &flags);
1406 }
1407 EXPORT_SYMBOL(debug_dma_mapping_error);
1408
1409 void debug_dma_unmap_page(struct device *dev, dma_addr_t addr,
1410                           size_t size, int direction, bool map_single)
1411 {
1412         struct dma_debug_entry ref = {
1413                 .type           = dma_debug_page,
1414                 .dev            = dev,
1415                 .dev_addr       = addr,
1416                 .size           = size,
1417                 .direction      = direction,
1418         };
1419
1420         if (unlikely(dma_debug_disabled()))
1421                 return;
1422
1423         if (map_single)
1424                 ref.type = dma_debug_single;
1425
1426         check_unmap(&ref);
1427 }
1428 EXPORT_SYMBOL(debug_dma_unmap_page);
1429
1430 void debug_dma_map_sg(struct device *dev, struct scatterlist *sg,
1431                       int nents, int mapped_ents, int direction)
1432 {
1433         struct dma_debug_entry *entry;
1434         struct scatterlist *s;
1435         int i;
1436
1437         if (unlikely(dma_debug_disabled()))
1438                 return;
1439
1440         for_each_sg(sg, s, mapped_ents, i) {
1441                 entry = dma_entry_alloc();
1442                 if (!entry)
1443                         return;
1444
1445                 entry->type           = dma_debug_sg;
1446                 entry->dev            = dev;
1447                 entry->pfn            = page_to_pfn(sg_page(s));
1448                 entry->offset         = s->offset,
1449                 entry->size           = sg_dma_len(s);
1450                 entry->dev_addr       = sg_dma_address(s);
1451                 entry->direction      = direction;
1452                 entry->sg_call_ents   = nents;
1453                 entry->sg_mapped_ents = mapped_ents;
1454
1455                 check_for_stack(dev, sg_page(s), s->offset);
1456
1457                 if (!PageHighMem(sg_page(s))) {
1458                         check_for_illegal_area(dev, sg_virt(s), sg_dma_len(s));
1459                 }
1460
1461                 check_sg_segment(dev, s);
1462
1463                 add_dma_entry(entry);
1464         }
1465 }
1466 EXPORT_SYMBOL(debug_dma_map_sg);
1467
1468 static int get_nr_mapped_entries(struct device *dev,
1469                                  struct dma_debug_entry *ref)
1470 {
1471         struct dma_debug_entry *entry;
1472         struct hash_bucket *bucket;
1473         unsigned long flags;
1474         int mapped_ents;
1475
1476         bucket       = get_hash_bucket(ref, &flags);
1477         entry        = bucket_find_exact(bucket, ref);
1478         mapped_ents  = 0;
1479
1480         if (entry)
1481                 mapped_ents = entry->sg_mapped_ents;
1482         put_hash_bucket(bucket, &flags);
1483
1484         return mapped_ents;
1485 }
1486
1487 void debug_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
1488                         int nelems, int dir)
1489 {
1490         struct scatterlist *s;
1491         int mapped_ents = 0, i;
1492
1493         if (unlikely(dma_debug_disabled()))
1494                 return;
1495
1496         for_each_sg(sglist, s, nelems, i) {
1497
1498                 struct dma_debug_entry ref = {
1499                         .type           = dma_debug_sg,
1500                         .dev            = dev,
1501                         .pfn            = page_to_pfn(sg_page(s)),
1502                         .offset         = s->offset,
1503                         .dev_addr       = sg_dma_address(s),
1504                         .size           = sg_dma_len(s),
1505                         .direction      = dir,
1506                         .sg_call_ents   = nelems,
1507                 };
1508
1509                 if (mapped_ents && i >= mapped_ents)
1510                         break;
1511
1512                 if (!i)
1513                         mapped_ents = get_nr_mapped_entries(dev, &ref);
1514
1515                 check_unmap(&ref);
1516         }
1517 }
1518 EXPORT_SYMBOL(debug_dma_unmap_sg);
1519
1520 void debug_dma_alloc_coherent(struct device *dev, size_t size,
1521                               dma_addr_t dma_addr, void *virt)
1522 {
1523         struct dma_debug_entry *entry;
1524
1525         if (unlikely(dma_debug_disabled()))
1526                 return;
1527
1528         if (unlikely(virt == NULL))
1529                 return;
1530
1531         /* handle vmalloc and linear addresses */
1532         if (!is_vmalloc_addr(virt) && !virt_addr_valid(virt))
1533                 return;
1534
1535         entry = dma_entry_alloc();
1536         if (!entry)
1537                 return;
1538
1539         entry->type      = dma_debug_coherent;
1540         entry->dev       = dev;
1541         entry->offset    = offset_in_page(virt);
1542         entry->size      = size;
1543         entry->dev_addr  = dma_addr;
1544         entry->direction = DMA_BIDIRECTIONAL;
1545
1546         if (is_vmalloc_addr(virt))
1547                 entry->pfn = vmalloc_to_pfn(virt);
1548         else
1549                 entry->pfn = page_to_pfn(virt_to_page(virt));
1550
1551         add_dma_entry(entry);
1552 }
1553 EXPORT_SYMBOL(debug_dma_alloc_coherent);
1554
1555 void debug_dma_free_coherent(struct device *dev, size_t size,
1556                          void *virt, dma_addr_t addr)
1557 {
1558         struct dma_debug_entry ref = {
1559                 .type           = dma_debug_coherent,
1560                 .dev            = dev,
1561                 .offset         = offset_in_page(virt),
1562                 .dev_addr       = addr,
1563                 .size           = size,
1564                 .direction      = DMA_BIDIRECTIONAL,
1565         };
1566
1567         /* handle vmalloc and linear addresses */
1568         if (!is_vmalloc_addr(virt) && !virt_addr_valid(virt))
1569                 return;
1570
1571         if (is_vmalloc_addr(virt))
1572                 ref.pfn = vmalloc_to_pfn(virt);
1573         else
1574                 ref.pfn = page_to_pfn(virt_to_page(virt));
1575
1576         if (unlikely(dma_debug_disabled()))
1577                 return;
1578
1579         check_unmap(&ref);
1580 }
1581 EXPORT_SYMBOL(debug_dma_free_coherent);
1582
1583 void debug_dma_map_resource(struct device *dev, phys_addr_t addr, size_t size,
1584                             int direction, dma_addr_t dma_addr)
1585 {
1586         struct dma_debug_entry *entry;
1587
1588         if (unlikely(dma_debug_disabled()))
1589                 return;
1590
1591         entry = dma_entry_alloc();
1592         if (!entry)
1593                 return;
1594
1595         entry->type             = dma_debug_resource;
1596         entry->dev              = dev;
1597         entry->pfn              = PHYS_PFN(addr);
1598         entry->offset           = offset_in_page(addr);
1599         entry->size             = size;
1600         entry->dev_addr         = dma_addr;
1601         entry->direction        = direction;
1602         entry->map_err_type     = MAP_ERR_NOT_CHECKED;
1603
1604         add_dma_entry(entry);
1605 }
1606 EXPORT_SYMBOL(debug_dma_map_resource);
1607
1608 void debug_dma_unmap_resource(struct device *dev, dma_addr_t dma_addr,
1609                               size_t size, int direction)
1610 {
1611         struct dma_debug_entry ref = {
1612                 .type           = dma_debug_resource,
1613                 .dev            = dev,
1614                 .dev_addr       = dma_addr,
1615                 .size           = size,
1616                 .direction      = direction,
1617         };
1618
1619         if (unlikely(dma_debug_disabled()))
1620                 return;
1621
1622         check_unmap(&ref);
1623 }
1624 EXPORT_SYMBOL(debug_dma_unmap_resource);
1625
1626 void debug_dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_handle,
1627                                    size_t size, int direction)
1628 {
1629         struct dma_debug_entry ref;
1630
1631         if (unlikely(dma_debug_disabled()))
1632                 return;
1633
1634         ref.type         = dma_debug_single;
1635         ref.dev          = dev;
1636         ref.dev_addr     = dma_handle;
1637         ref.size         = size;
1638         ref.direction    = direction;
1639         ref.sg_call_ents = 0;
1640
1641         check_sync(dev, &ref, true);
1642 }
1643 EXPORT_SYMBOL(debug_dma_sync_single_for_cpu);
1644
1645 void debug_dma_sync_single_for_device(struct device *dev,
1646                                       dma_addr_t dma_handle, size_t size,
1647                                       int direction)
1648 {
1649         struct dma_debug_entry ref;
1650
1651         if (unlikely(dma_debug_disabled()))
1652                 return;
1653
1654         ref.type         = dma_debug_single;
1655         ref.dev          = dev;
1656         ref.dev_addr     = dma_handle;
1657         ref.size         = size;
1658         ref.direction    = direction;
1659         ref.sg_call_ents = 0;
1660
1661         check_sync(dev, &ref, false);
1662 }
1663 EXPORT_SYMBOL(debug_dma_sync_single_for_device);
1664
1665 void debug_dma_sync_single_range_for_cpu(struct device *dev,
1666                                          dma_addr_t dma_handle,
1667                                          unsigned long offset, size_t size,
1668                                          int direction)
1669 {
1670         struct dma_debug_entry ref;
1671
1672         if (unlikely(dma_debug_disabled()))
1673                 return;
1674
1675         ref.type         = dma_debug_single;
1676         ref.dev          = dev;
1677         ref.dev_addr     = dma_handle;
1678         ref.size         = offset + size;
1679         ref.direction    = direction;
1680         ref.sg_call_ents = 0;
1681
1682         check_sync(dev, &ref, true);
1683 }
1684 EXPORT_SYMBOL(debug_dma_sync_single_range_for_cpu);
1685
1686 void debug_dma_sync_single_range_for_device(struct device *dev,
1687                                             dma_addr_t dma_handle,
1688                                             unsigned long offset,
1689                                             size_t size, int direction)
1690 {
1691         struct dma_debug_entry ref;
1692
1693         if (unlikely(dma_debug_disabled()))
1694                 return;
1695
1696         ref.type         = dma_debug_single;
1697         ref.dev          = dev;
1698         ref.dev_addr     = dma_handle;
1699         ref.size         = offset + size;
1700         ref.direction    = direction;
1701         ref.sg_call_ents = 0;
1702
1703         check_sync(dev, &ref, false);
1704 }
1705 EXPORT_SYMBOL(debug_dma_sync_single_range_for_device);
1706
1707 void debug_dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
1708                                int nelems, int direction)
1709 {
1710         struct scatterlist *s;
1711         int mapped_ents = 0, i;
1712
1713         if (unlikely(dma_debug_disabled()))
1714                 return;
1715
1716         for_each_sg(sg, s, nelems, i) {
1717
1718                 struct dma_debug_entry ref = {
1719                         .type           = dma_debug_sg,
1720                         .dev            = dev,
1721                         .pfn            = page_to_pfn(sg_page(s)),
1722                         .offset         = s->offset,
1723                         .dev_addr       = sg_dma_address(s),
1724                         .size           = sg_dma_len(s),
1725                         .direction      = direction,
1726                         .sg_call_ents   = nelems,
1727                 };
1728
1729                 if (!i)
1730                         mapped_ents = get_nr_mapped_entries(dev, &ref);
1731
1732                 if (i >= mapped_ents)
1733                         break;
1734
1735                 check_sync(dev, &ref, true);
1736         }
1737 }
1738 EXPORT_SYMBOL(debug_dma_sync_sg_for_cpu);
1739
1740 void debug_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
1741                                   int nelems, int direction)
1742 {
1743         struct scatterlist *s;
1744         int mapped_ents = 0, i;
1745
1746         if (unlikely(dma_debug_disabled()))
1747                 return;
1748
1749         for_each_sg(sg, s, nelems, i) {
1750
1751                 struct dma_debug_entry ref = {
1752                         .type           = dma_debug_sg,
1753                         .dev            = dev,
1754                         .pfn            = page_to_pfn(sg_page(s)),
1755                         .offset         = s->offset,
1756                         .dev_addr       = sg_dma_address(s),
1757                         .size           = sg_dma_len(s),
1758                         .direction      = direction,
1759                         .sg_call_ents   = nelems,
1760                 };
1761                 if (!i)
1762                         mapped_ents = get_nr_mapped_entries(dev, &ref);
1763
1764                 if (i >= mapped_ents)
1765                         break;
1766
1767                 check_sync(dev, &ref, false);
1768         }
1769 }
1770 EXPORT_SYMBOL(debug_dma_sync_sg_for_device);
1771
1772 static int __init dma_debug_driver_setup(char *str)
1773 {
1774         int i;
1775
1776         for (i = 0; i < NAME_MAX_LEN - 1; ++i, ++str) {
1777                 current_driver_name[i] = *str;
1778                 if (*str == 0)
1779                         break;
1780         }
1781
1782         if (current_driver_name[0])
1783                 pr_info("DMA-API: enable driver filter for driver [%s]\n",
1784                         current_driver_name);
1785
1786
1787         return 1;
1788 }
1789 __setup("dma_debug_driver=", dma_debug_driver_setup);