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                 cond_resched();
 446         }
 447 }
 448
 449 /*
 450  * For each mapping (initial cacheline in the case of
 451  * dma_alloc_coherent/dma_map_page, initial cacheline in each page of a
 452  * scatterlist, or the cacheline specified in dma_map_single) insert
 453  * into this tree using the cacheline as the key. At
 454  * dma_unmap_{single|sg|page} or dma_free_coherent delete the entry.  If
 455  * the entry already exists at insertion time add a tag as a reference
 456  * count for the overlapping mappings.  For now, the overlap tracking
 457  * just ensures that 'unmaps' balance 'maps' before marking the
 458  * cacheline idle, but we should also be flagging overlaps as an API
 459  * violation.
 460  *
 461  * Memory usage is mostly constrained by the maximum number of available
 462  * dma-debug entries in that we need a free dma_debug_entry before
 463  * inserting into the tree.  In the case of dma_map_page and
 464  * dma_alloc_coherent there is only one dma_debug_entry and one
 465  * dma_active_cacheline entry to track per event.  dma_map_sg(), on the
 466  * other hand, consumes a single dma_debug_entry, but inserts 'nents'
 467  * entries into the tree.
 468  *
 469  * At any time debug_dma_assert_idle() can be called to trigger a
 470  * warning if any cachelines in the given page are in the active set.
 471  */
 472 static RADIX_TREE(dma_active_cacheline, GFP_NOWAIT);
 473 static DEFINE_SPINLOCK(radix_lock);
 474 #define ACTIVE_CACHELINE_MAX_OVERLAP ((1 << RADIX_TREE_MAX_TAGS) - 1)
 475 #define CACHELINE_PER_PAGE_SHIFT (PAGE_SHIFT - L1_CACHE_SHIFT)
 476 #define CACHELINES_PER_PAGE (1 << CACHELINE_PER_PAGE_SHIFT)
 477
 478 static phys_addr_t to_cacheline_number(struct dma_debug_entry *entry)
 479 {
 480         return (entry->pfn << CACHELINE_PER_PAGE_SHIFT) +
 481                 (entry->offset >> L1_CACHE_SHIFT);
 482 }
 483
 484 static int active_cacheline_read_overlap(phys_addr_t cln)
 485 {
 486         int overlap = 0, i;
 487
 488         for (i = RADIX_TREE_MAX_TAGS - 1; i >= 0; i--)
 489                 if (radix_tree_tag_get(&dma_active_cacheline, cln, i))
 490                         overlap |= 1 << i;
 491         return overlap;
 492 }
 493
 494 static int active_cacheline_set_overlap(phys_addr_t cln, int overlap)
 495 {
 496         int i;
 497
 498         if (overlap > ACTIVE_CACHELINE_MAX_OVERLAP || overlap < 0)
 499                 return overlap;
 500
 501         for (i = RADIX_TREE_MAX_TAGS - 1; i >= 0; i--)
 502                 if (overlap & 1 << i)
 503                         radix_tree_tag_set(&dma_active_cacheline, cln, i);
 504                 else
 505                         radix_tree_tag_clear(&dma_active_cacheline, cln, i);
 506
 507         return overlap;
 508 }
 509
 510 static void active_cacheline_inc_overlap(phys_addr_t cln)
 511 {
 512         int overlap = active_cacheline_read_overlap(cln);
 513
 514         overlap = active_cacheline_set_overlap(cln, ++overlap);
 515
 516         /* If we overflowed the overlap counter then we're potentially
 517          * leaking dma-mappings.  Otherwise, if maps and unmaps are
 518          * balanced then this overflow may cause false negatives in
 519          * debug_dma_assert_idle() as the cacheline may be marked idle
 520          * prematurely.
 521          */
 522         WARN_ONCE(overlap > ACTIVE_CACHELINE_MAX_OVERLAP,
 523                   "DMA-API: exceeded %d overlapping mappings of cacheline %pa\n",
 524                   ACTIVE_CACHELINE_MAX_OVERLAP, &cln);
 525 }
 526
 527 static int active_cacheline_dec_overlap(phys_addr_t cln)
 528 {
 529         int overlap = active_cacheline_read_overlap(cln);
 530
 531         return active_cacheline_set_overlap(cln, --overlap);
 532 }
 533
 534 static int active_cacheline_insert(struct dma_debug_entry *entry)
 535 {
 536         phys_addr_t cln = to_cacheline_number(entry);
 537         unsigned long flags;
 538         int rc;
 539
 540         /* If the device is not writing memory then we don't have any
 541          * concerns about the cpu consuming stale data.  This mitigates
 542          * legitimate usages of overlapping mappings.
 543          */
 544         if (entry->direction == DMA_TO_DEVICE)
 545                 return 0;
 546
 547         spin_lock_irqsave(&radix_lock, flags);
 548         rc = radix_tree_insert(&dma_active_cacheline, cln, entry);
 549         if (rc == -EEXIST)
 550                 active_cacheline_inc_overlap(cln);
 551         spin_unlock_irqrestore(&radix_lock, flags);
 552
 553         return rc;
 554 }
 555
 556 static void active_cacheline_remove(struct dma_debug_entry *entry)
 557 {
 558         phys_addr_t cln = to_cacheline_number(entry);
 559         unsigned long flags;
 560
 561         /* ...mirror the insert case */
 562         if (entry->direction == DMA_TO_DEVICE)
 563                 return;
 564
 565         spin_lock_irqsave(&radix_lock, flags);
 566         /* since we are counting overlaps the final put of the
 567          * cacheline will occur when the overlap count is 0.
 568          * active_cacheline_dec_overlap() returns -1 in that case
 569          */
 570         if (active_cacheline_dec_overlap(cln) < 0)
 571                 radix_tree_delete(&dma_active_cacheline, cln);
 572         spin_unlock_irqrestore(&radix_lock, flags);
 573 }
 574
 575 /**
 576  * debug_dma_assert_idle() - assert that a page is not undergoing dma
 577  * @page: page to lookup in the dma_active_cacheline tree
 578  *
 579  * Place a call to this routine in cases where the cpu touching the page
 580  * before the dma completes (page is dma_unmapped) will lead to data
 581  * corruption.
 582  */
 583 void debug_dma_assert_idle(struct page *page)
 584 {
 585         static struct dma_debug_entry *ents[CACHELINES_PER_PAGE];
 586         struct dma_debug_entry *entry = NULL;
 587         void **results = (void **) &ents;
 588         unsigned int nents, i;
 589         unsigned long flags;
 590         phys_addr_t cln;
 591
 592         if (dma_debug_disabled())
 593                 return;
 594
 595         if (!page)
 596                 return;
 597
 598         cln = (phys_addr_t) page_to_pfn(page) << CACHELINE_PER_PAGE_SHIFT;
 599         spin_lock_irqsave(&radix_lock, flags);
 600         nents = radix_tree_gang_lookup(&dma_active_cacheline, results, cln,
 601                                        CACHELINES_PER_PAGE);
 602         for (i = 0; i < nents; i++) {
 603                 phys_addr_t ent_cln = to_cacheline_number(ents[i]);
 604
 605                 if (ent_cln == cln) {
 606                         entry = ents[i];
 607                         break;
 608                 } else if (ent_cln >= cln + CACHELINES_PER_PAGE)
 609                         break;
 610         }
 611         spin_unlock_irqrestore(&radix_lock, flags);
 612
 613         if (!entry)
 614                 return;
 615
 616         cln = to_cacheline_number(entry);
 617         err_printk(entry->dev, entry,
 618                    "DMA-API: cpu touching an active dma mapped cacheline [cln=%pa]\n",
 619                    &cln);
 620 }
 621
 622 /*
 623  * Wrapper function for adding an entry to the hash.
 624  * This function takes care of locking itself.
 625  */
 626 static void add_dma_entry(struct dma_debug_entry *entry)
 627 {
 628         struct hash_bucket *bucket;
 629         unsigned long flags;
 630         int rc;
 631
 632         bucket = get_hash_bucket(entry, &flags);
 633         hash_bucket_add(bucket, entry);
 634         put_hash_bucket(bucket, &flags);
 635
 636         rc = active_cacheline_insert(entry);
 637         if (rc == -ENOMEM) {
 638                 pr_err("DMA-API: cacheline tracking ENOMEM, dma-debug disabled\n");
 639                 global_disable = true;
 640         }
 641
 642         /* TODO: report -EEXIST errors here as overlapping mappings are
 643          * not supported by the DMA API
 644          */
 645 }
 646
 647 static struct dma_debug_entry *__dma_entry_alloc(void)
 648 {
 649         struct dma_debug_entry *entry;
 650
 651         entry = list_entry(free_entries.next, struct dma_debug_entry, list);
 652         list_del(&entry->list);
 653         memset(entry, 0, sizeof(*entry));
 654
 655         num_free_entries -= 1;
 656         if (num_free_entries < min_free_entries)
 657                 min_free_entries = num_free_entries;
 658
 659         return entry;
 660 }
 661
 662 /* struct dma_entry allocator
 663  *
 664  * The next two functions implement the allocator for
 665  * struct dma_debug_entries.
 666  */
 667 static struct dma_debug_entry *dma_entry_alloc(void)
 668 {
 669         struct dma_debug_entry *entry;
 670         unsigned long flags;
 671
 672         spin_lock_irqsave(&free_entries_lock, flags);
 673
 674         if (list_empty(&free_entries)) {
 675                 global_disable = true;
 676                 spin_unlock_irqrestore(&free_entries_lock, flags);
 677                 pr_err("DMA-API: debugging out of memory - disabling\n");
 678                 return NULL;
 679         }
 680
 681         entry = __dma_entry_alloc();
 682
 683         spin_unlock_irqrestore(&free_entries_lock, flags);
 684
 685 #ifdef CONFIG_STACKTRACE
 686         entry->stacktrace.max_entries = DMA_DEBUG_STACKTRACE_ENTRIES;
 687         entry->stacktrace.entries = entry->st_entries;
 688         entry->stacktrace.skip = 2;
 689         save_stack_trace(&entry->stacktrace);
 690 #endif
 691
 692         return entry;
 693 }
 694
 695 static void dma_entry_free(struct dma_debug_entry *entry)
 696 {
 697         unsigned long flags;
 698
 699         active_cacheline_remove(entry);
 700
 701         /*
 702          * add to beginning of the list - this way the entries are
 703          * more likely cache hot when they are reallocated.
 704          */
 705         spin_lock_irqsave(&free_entries_lock, flags);
 706         list_add(&entry->list, &free_entries);
 707         num_free_entries += 1;
 708         spin_unlock_irqrestore(&free_entries_lock, flags);
 709 }
 710
 711 int dma_debug_resize_entries(u32 num_entries)
 712 {
 713         int i, delta, ret = 0;
 714         unsigned long flags;
 715         struct dma_debug_entry *entry;
 716         LIST_HEAD(tmp);
 717
 718         spin_lock_irqsave(&free_entries_lock, flags);
 719
 720         if (nr_total_entries < num_entries) {
 721                 delta = num_entries - nr_total_entries;
 722
 723                 spin_unlock_irqrestore(&free_entries_lock, flags);
 724
 725                 for (i = 0; i < delta; i++) {
 726                         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 727                         if (!entry)
 728                                 break;
 729
 730                         list_add_tail(&entry->list, &tmp);
 731                 }
 732
 733                 spin_lock_irqsave(&free_entries_lock, flags);
 734
 735                 list_splice(&tmp, &free_entries);
 736                 nr_total_entries += i;
 737                 num_free_entries += i;
 738         } else {
 739                 delta = nr_total_entries - num_entries;
 740
 741                 for (i = 0; i < delta && !list_empty(&free_entries); i++) {
 742                         entry = __dma_entry_alloc();
 743                         kfree(entry);
 744                 }
 745
 746                 nr_total_entries -= i;
 747         }
 748
 749         if (nr_total_entries != num_entries)
 750                 ret = 1;
 751
 752         spin_unlock_irqrestore(&free_entries_lock, flags);
 753
 754         return ret;
 755 }
 756
 757 /*
 758  * DMA-API debugging init code
 759  *
 760  * The init code does two things:
 761  *   1. Initialize core data structures
 762  *   2. Preallocate a given number of dma_debug_entry structs
 763  */
 764
 765 static int prealloc_memory(u32 num_entries)
 766 {
 767         struct dma_debug_entry *entry, *next_entry;
 768         int i;
 769
 770         for (i = 0; i < num_entries; ++i) {
 771                 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 772                 if (!entry)
 773                         goto out_err;
 774
 775                 list_add_tail(&entry->list, &free_entries);
 776         }
 777
 778         num_free_entries = num_entries;
 779         min_free_entries = num_entries;
 780
 781         pr_info("DMA-API: preallocated %d debug entries\n", num_entries);
 782
 783         return 0;
 784
 785 out_err:
 786
 787         list_for_each_entry_safe(entry, next_entry, &free_entries, list) {
 788                 list_del(&entry->list);
 789                 kfree(entry);
 790         }
 791
 792         return -ENOMEM;
 793 }
 794
 795 static ssize_t filter_read(struct file *file, char __user *user_buf,
 796                            size_t count, loff_t *ppos)
 797 {
 798         char buf[NAME_MAX_LEN + 1];
 799         unsigned long flags;
 800         int len;
 801
 802         if (!current_driver_name[0])
 803                 return 0;
 804
 805         /*
 806          * We can't copy to userspace directly because current_driver_name can
 807          * only be read under the driver_name_lock with irqs disabled. So
 808          * create a temporary copy first.
 809          */
 810         read_lock_irqsave(&driver_name_lock, flags);
 811         len = scnprintf(buf, NAME_MAX_LEN + 1, "%s\n", current_driver_name);
 812         read_unlock_irqrestore(&driver_name_lock, flags);
 813
 814         return simple_read_from_buffer(user_buf, count, ppos, buf, len);
 815 }
 816
 817 static ssize_t filter_write(struct file *file, const char __user *userbuf,
 818                             size_t count, loff_t *ppos)
 819 {
 820         char buf[NAME_MAX_LEN];
 821         unsigned long flags;
 822         size_t len;
 823         int i;
 824
 825         /*
 826          * We can't copy from userspace directly. Access to
 827          * current_driver_name is protected with a write_lock with irqs
 828          * disabled. Since copy_from_user can fault and may sleep we
 829          * need to copy to temporary buffer first
 830          */
 831         len = min(count, (size_t)(NAME_MAX_LEN - 1));
 832         if (copy_from_user(buf, userbuf, len))
 833                 return -EFAULT;
 834
 835         buf[len] = 0;
 836
 837         write_lock_irqsave(&driver_name_lock, flags);
 838
 839         /*
 840          * Now handle the string we got from userspace very carefully.
 841          * The rules are:
 842          *         - only use the first token we got
 843          *         - token delimiter is everything looking like a space
 844          *           character (' ', '\n', '\t' ...)
 845          *
 846          */
 847         if (!isalnum(buf[0])) {
 848                 /*
 849                  * If the first character userspace gave us is not
 850                  * alphanumerical then assume the filter should be
 851                  * switched off.
 852                  */
 853                 if (current_driver_name[0])
 854                         pr_info("DMA-API: switching off dma-debug driver filter\n");
 855                 current_driver_name[0] = 0;
 856                 current_driver = NULL;
 857                 goto out_unlock;
 858         }
 859
 860         /*
 861          * Now parse out the first token and use it as the name for the
 862          * driver to filter for.
 863          */
 864         for (i = 0; i < NAME_MAX_LEN - 1; ++i) {
 865                 current_driver_name[i] = buf[i];
 866                 if (isspace(buf[i]) || buf[i] == ' ' || buf[i] == 0)
 867                         break;
 868         }
 869         current_driver_name[i] = 0;
 870         current_driver = NULL;
 871
 872         pr_info("DMA-API: enable driver filter for driver [%s]\n",
 873                 current_driver_name);
 874
 875 out_unlock:
 876         write_unlock_irqrestore(&driver_name_lock, flags);
 877
 878         return count;
 879 }
 880
 881 static const struct file_operations filter_fops = {
 882         .read  = filter_read,
 883         .write = filter_write,
 884         .llseek = default_llseek,
 885 };
 886
 887 static int dma_debug_fs_init(void)
 888 {
 889         dma_debug_dent = debugfs_create_dir("dma-api", NULL);
 890         if (!dma_debug_dent) {
 891                 pr_err("DMA-API: can not create debugfs directory\n");
 892                 return -ENOMEM;
 893         }
 894
 895         global_disable_dent = debugfs_create_bool("disabled", 0444,
 896                         dma_debug_dent,
 897                         &global_disable);
 898         if (!global_disable_dent)
 899                 goto out_err;
 900
 901         error_count_dent = debugfs_create_u32("error_count", 0444,
 902                         dma_debug_dent, &error_count);
 903         if (!error_count_dent)
 904                 goto out_err;
 905
 906         show_all_errors_dent = debugfs_create_u32("all_errors", 0644,
 907                         dma_debug_dent,
 908                         &show_all_errors);
 909         if (!show_all_errors_dent)
 910                 goto out_err;
 911
 912         show_num_errors_dent = debugfs_create_u32("num_errors", 0644,
 913                         dma_debug_dent,
 914                         &show_num_errors);
 915         if (!show_num_errors_dent)
 916                 goto out_err;
 917
 918         num_free_entries_dent = debugfs_create_u32("num_free_entries", 0444,
 919                         dma_debug_dent,
 920                         &num_free_entries);
 921         if (!num_free_entries_dent)
 922                 goto out_err;
 923
 924         min_free_entries_dent = debugfs_create_u32("min_free_entries", 0444,
 925                         dma_debug_dent,
 926                         &min_free_entries);
 927         if (!min_free_entries_dent)
 928                 goto out_err;
 929
 930         filter_dent = debugfs_create_file("driver_filter", 0644,
 931                                           dma_debug_dent, NULL, &filter_fops);
 932         if (!filter_dent)
 933                 goto out_err;
 934
 935         return 0;
 936
 937 out_err:
 938         debugfs_remove_recursive(dma_debug_dent);
 939
 940         return -ENOMEM;
 941 }
 942
 943 static int device_dma_allocations(struct device *dev, struct dma_debug_entry **out_entry)
 944 {
 945         struct dma_debug_entry *entry;
 946         unsigned long flags;
 947         int count = 0, i;
 948
 949         for (i = 0; i < HASH_SIZE; ++i) {
 950                 spin_lock_irqsave(&dma_entry_hash[i].lock, flags);
 951                 list_for_each_entry(entry, &dma_entry_hash[i].list, list) {
 952                         if (entry->dev == dev) {
 953                                 count += 1;
 954                                 *out_entry = entry;
 955                         }
 956                 }
 957                 spin_unlock_irqrestore(&dma_entry_hash[i].lock, flags);
 958         }
 959
 960         return count;
 961 }
 962
 963 static int dma_debug_device_change(struct notifier_block *nb, unsigned long action, void *data)
 964 {
 965         struct device *dev = data;
 966         struct dma_debug_entry *uninitialized_var(entry);
 967         int count;
 968
 969         if (dma_debug_disabled())
 970                 return 0;
 971
 972         switch (action) {
 973         case BUS_NOTIFY_UNBOUND_DRIVER:
 974                 count = device_dma_allocations(dev, &entry);
 975                 if (count == 0)
 976                         break;
 977                 err_printk(dev, entry, "DMA-API: device driver has pending "
 978                                 "DMA allocations while released from device "
 979                                 "[count=%d]\n"
 980                                 "One of leaked entries details: "
 981                                 "[device address=0x%016llx] [size=%llu bytes] "
 982                                 "[mapped with %s] [mapped as %s]\n",
 983                         count, entry->dev_addr, entry->size,
 984                         dir2name[entry->direction], type2name[entry->type]);
 985                 break;
 986         default:
 987                 break;
 988         }
 989
 990         return 0;
 991 }
 992
 993 void dma_debug_add_bus(struct bus_type *bus)
 994 {
 995         struct notifier_block *nb;
 996
 997         if (dma_debug_disabled())
 998                 return;
 999
1000         nb = kzalloc(sizeof(struct notifier_block), GFP_KERNEL);
1001         if (nb == NULL) {
1002                 pr_err("dma_debug_add_bus: out of memory\n");
1003                 return;
1004         }
1005
1006         nb->notifier_call = dma_debug_device_change;
1007
1008         bus_register_notifier(bus, nb);
1009 }
1010
1011 static int dma_debug_init(void)
1012 {
1013         int i;
1014
1015         /* Do not use dma_debug_initialized here, since we really want to be
1016          * called to set dma_debug_initialized
1017          */
1018         if (global_disable)
1019                 return 0;
1020
1021         for (i = 0; i < HASH_SIZE; ++i) {
1022                 INIT_LIST_HEAD(&dma_entry_hash[i].list);
1023                 spin_lock_init(&dma_entry_hash[i].lock);
1024         }
1025
1026         if (dma_debug_fs_init() != 0) {
1027                 pr_err("DMA-API: error creating debugfs entries - disabling\n");
1028                 global_disable = true;
1029
1030                 return 0;
1031         }
1032
1033         if (prealloc_memory(nr_prealloc_entries) != 0) {
1034                 pr_err("DMA-API: debugging out of memory error - disabled\n");
1035                 global_disable = true;
1036
1037                 return 0;
1038         }
1039
1040         nr_total_entries = num_free_entries;
1041
1042         dma_debug_initialized = true;
1043
1044         pr_info("DMA-API: debugging enabled by kernel config\n");
1045         return 0;
1046 }
1047 core_initcall(dma_debug_init);
1048
1049 static __init int dma_debug_cmdline(char *str)
1050 {
1051         if (!str)
1052                 return -EINVAL;
1053
1054         if (strncmp(str, "off", 3) == 0) {
1055                 pr_info("DMA-API: debugging disabled on kernel command line\n");
1056                 global_disable = true;
1057         }
1058
1059         return 0;
1060 }
1061
1062 static __init int dma_debug_entries_cmdline(char *str)
1063 {
1064         if (!str)
1065                 return -EINVAL;
1066         if (!get_option(&str, &nr_prealloc_entries))
1067                 nr_prealloc_entries = PREALLOC_DMA_DEBUG_ENTRIES;
1068         return 0;
1069 }
1070
1071 __setup("dma_debug=", dma_debug_cmdline);
1072 __setup("dma_debug_entries=", dma_debug_entries_cmdline);
1073
1074 static void check_unmap(struct dma_debug_entry *ref)
1075 {
1076         struct dma_debug_entry *entry;
1077         struct hash_bucket *bucket;
1078         unsigned long flags;
1079
1080         bucket = get_hash_bucket(ref, &flags);
1081         entry = bucket_find_exact(bucket, ref);
1082
1083         if (!entry) {
1084                 /* must drop lock before calling dma_mapping_error */
1085                 put_hash_bucket(bucket, &flags);
1086
1087                 if (dma_mapping_error(ref->dev, ref->dev_addr)) {
1088                         err_printk(ref->dev, NULL,
1089                                    "DMA-API: device driver tries to free an "
1090                                    "invalid DMA memory address\n");
1091                 } else {
1092                         err_printk(ref->dev, NULL,
1093                                    "DMA-API: device driver tries to free DMA "
1094                                    "memory it has not allocated [device "
1095                                    "address=0x%016llx] [size=%llu bytes]\n",
1096                                    ref->dev_addr, ref->size);
1097                 }
1098                 return;
1099         }
1100
1101         if (ref->size != entry->size) {
1102                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
1103                            "DMA memory with different size "
1104                            "[device address=0x%016llx] [map size=%llu bytes] "
1105                            "[unmap size=%llu bytes]\n",
1106                            ref->dev_addr, entry->size, ref->size);
1107         }
1108
1109         if (ref->type != entry->type) {
1110                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
1111                            "DMA memory with wrong function "
1112                            "[device address=0x%016llx] [size=%llu bytes] "
1113                            "[mapped as %s] [unmapped as %s]\n",
1114                            ref->dev_addr, ref->size,
1115                            type2name[entry->type], type2name[ref->type]);
1116         } else if ((entry->type == dma_debug_coherent) &&
1117                    (phys_addr(ref) != phys_addr(entry))) {
1118                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
1119                            "DMA memory with different CPU address "
1120                            "[device address=0x%016llx] [size=%llu bytes] "
1121                            "[cpu alloc address=0x%016llx] "
1122                            "[cpu free address=0x%016llx]",
1123                            ref->dev_addr, ref->size,
1124                            phys_addr(entry),
1125                            phys_addr(ref));
1126         }
1127
1128         if (ref->sg_call_ents && ref->type == dma_debug_sg &&
1129             ref->sg_call_ents != entry->sg_call_ents) {
1130                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
1131                            "DMA sg list with different entry count "
1132                            "[map count=%d] [unmap count=%d]\n",
1133                            entry->sg_call_ents, ref->sg_call_ents);
1134         }
1135
1136         /*
1137          * This may be no bug in reality - but most implementations of the
1138          * DMA API don't handle this properly, so check for it here
1139          */
1140         if (ref->direction != entry->direction) {
1141                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
1142                            "DMA memory with different direction "
1143                            "[device address=0x%016llx] [size=%llu bytes] "
1144                            "[mapped with %s] [unmapped with %s]\n",
1145                            ref->dev_addr, ref->size,
1146                            dir2name[entry->direction],
1147                            dir2name[ref->direction]);
1148         }
1149
1150         /*
1151          * Drivers should use dma_mapping_error() to check the returned
1152          * addresses of dma_map_single() and dma_map_page().
1153          * If not, print this warning message. See Documentation/DMA-API.txt.
1154          */
1155         if (entry->map_err_type == MAP_ERR_NOT_CHECKED) {
1156                 err_printk(ref->dev, entry,
1157                            "DMA-API: device driver failed to check map error"
1158                            "[device address=0x%016llx] [size=%llu bytes] "
1159                            "[mapped as %s]",
1160                            ref->dev_addr, ref->size,
1161                            type2name[entry->type]);
1162         }
1163
1164         hash_bucket_del(entry);
1165         dma_entry_free(entry);
1166
1167         put_hash_bucket(bucket, &flags);
1168 }
1169
1170 static void check_for_stack(struct device *dev,
1171                             struct page *page, size_t offset)
1172 {
1173         void *addr;
1174         struct vm_struct *stack_vm_area = task_stack_vm_area(current);
1175
1176         if (!stack_vm_area) {
1177                 /* Stack is direct-mapped. */
1178                 if (PageHighMem(page))
1179                         return;
1180                 addr = page_address(page) + offset;
1181                 if (object_is_on_stack(addr))
1182                         err_printk(dev, NULL, "DMA-API: device driver maps memory from stack [addr=%p]\n", addr);
1183         } else {
1184                 /* Stack is vmalloced. */
1185                 int i;
1186
1187                 for (i = 0; i < stack_vm_area->nr_pages; i++) {
1188                         if (page != stack_vm_area->pages[i])
1189                                 continue;
1190
1191                         addr = (u8 *)current->stack + i * PAGE_SIZE + offset;
1192                         err_printk(dev, NULL, "DMA-API: device driver maps memory from stack [probable addr=%p]\n", addr);
1193                         break;
1194                 }
1195         }
1196 }
1197
1198 static inline bool overlap(void *addr, unsigned long len, void *start, void *end)
1199 {
1200         unsigned long a1 = (unsigned long)addr;
1201         unsigned long b1 = a1 + len;
1202         unsigned long a2 = (unsigned long)start;
1203         unsigned long b2 = (unsigned long)end;
1204
1205         return !(b1 <= a2 || a1 >= b2);
1206 }
1207
1208 static void check_for_illegal_area(struct device *dev, void *addr, unsigned long len)
1209 {
1210         if (overlap(addr, len, _stext, _etext) ||
1211             overlap(addr, len, __start_rodata, __end_rodata))
1212                 err_printk(dev, NULL, "DMA-API: device driver maps memory from kernel text or rodata [addr=%p] [len=%lu]\n", addr, len);
1213 }
1214
1215 static void check_sync(struct device *dev,
1216                        struct dma_debug_entry *ref,
1217                        bool to_cpu)
1218 {
1219         struct dma_debug_entry *entry;
1220         struct hash_bucket *bucket;
1221         unsigned long flags;
1222
1223         bucket = get_hash_bucket(ref, &flags);
1224
1225         entry = bucket_find_contain(&bucket, ref, &flags);
1226
1227         if (!entry) {
1228                 err_printk(dev, NULL, "DMA-API: device driver tries "
1229                                 "to sync DMA memory it has not allocated "
1230                                 "[device address=0x%016llx] [size=%llu bytes]\n",
1231                                 (unsigned long long)ref->dev_addr, ref->size);
1232                 goto out;
1233         }
1234
1235         if (ref->size > entry->size) {
1236                 err_printk(dev, entry, "DMA-API: device driver syncs"
1237                                 " DMA memory outside allocated range "
1238                                 "[device address=0x%016llx] "
1239                                 "[allocation size=%llu bytes] "
1240                                 "[sync offset+size=%llu]\n",
1241                                 entry->dev_addr, entry->size,
1242                                 ref->size);
1243         }
1244
1245         if (entry->direction == DMA_BIDIRECTIONAL)
1246                 goto out;
1247
1248         if (ref->direction != entry->direction) {
1249                 err_printk(dev, entry, "DMA-API: device driver syncs "
1250                                 "DMA memory with different direction "
1251                                 "[device address=0x%016llx] [size=%llu bytes] "
1252                                 "[mapped with %s] [synced with %s]\n",
1253                                 (unsigned long long)ref->dev_addr, entry->size,
1254                                 dir2name[entry->direction],
1255                                 dir2name[ref->direction]);
1256         }
1257
1258         if (to_cpu && !(entry->direction == DMA_FROM_DEVICE) &&
1259                       !(ref->direction == DMA_TO_DEVICE))
1260                 err_printk(dev, entry, "DMA-API: device driver syncs "
1261                                 "device read-only DMA memory for cpu "
1262                                 "[device address=0x%016llx] [size=%llu bytes] "
1263                                 "[mapped with %s] [synced with %s]\n",
1264                                 (unsigned long long)ref->dev_addr, entry->size,
1265                                 dir2name[entry->direction],
1266                                 dir2name[ref->direction]);
1267
1268         if (!to_cpu && !(entry->direction == DMA_TO_DEVICE) &&
1269                        !(ref->direction == DMA_FROM_DEVICE))
1270                 err_printk(dev, entry, "DMA-API: device driver syncs "
1271                                 "device write-only DMA memory to device "
1272                                 "[device address=0x%016llx] [size=%llu bytes] "
1273                                 "[mapped with %s] [synced with %s]\n",
1274                                 (unsigned long long)ref->dev_addr, entry->size,
1275                                 dir2name[entry->direction],
1276                                 dir2name[ref->direction]);
1277
1278         if (ref->sg_call_ents && ref->type == dma_debug_sg &&
1279             ref->sg_call_ents != entry->sg_call_ents) {
1280                 err_printk(ref->dev, entry, "DMA-API: device driver syncs "
1281                            "DMA sg list with different entry count "
1282                            "[map count=%d] [sync count=%d]\n",
1283                            entry->sg_call_ents, ref->sg_call_ents);
1284         }
1285
1286 out:
1287         put_hash_bucket(bucket, &flags);
1288 }
1289
1290 static void check_sg_segment(struct device *dev, struct scatterlist *sg)
1291 {
1292 #ifdef CONFIG_DMA_API_DEBUG_SG
1293         unsigned int max_seg = dma_get_max_seg_size(dev);
1294         u64 start, end, boundary = dma_get_seg_boundary(dev);
1295
1296         /*
1297          * Either the driver forgot to set dma_parms appropriately, or
1298          * whoever generated the list forgot to check them.
1299          */
1300         if (sg->length > max_seg)
1301                 err_printk(dev, NULL, "DMA-API: mapping sg segment longer than device claims to support [len=%u] [max=%u]\n",
1302                            sg->length, max_seg);
1303         /*
1304          * In some cases this could potentially be the DMA API
1305          * implementation's fault, but it would usually imply that
1306          * the scatterlist was built inappropriately to begin with.
1307          */
1308         start = sg_dma_address(sg);
1309         end = start + sg_dma_len(sg) - 1;
1310         if ((start ^ end) & ~boundary)
1311                 err_printk(dev, NULL, "DMA-API: mapping sg segment across boundary [start=0x%016llx] [end=0x%016llx] [boundary=0x%016llx]\n",
1312                            start, end, boundary);
1313 #endif
1314 }
1315
1316 void debug_dma_map_page(struct device *dev, struct page *page, size_t offset,
1317                         size_t size, int direction, dma_addr_t dma_addr,
1318                         bool map_single)
1319 {
1320         struct dma_debug_entry *entry;
1321
1322         if (unlikely(dma_debug_disabled()))
1323                 return;
1324
1325         if (dma_mapping_error(dev, dma_addr))
1326                 return;
1327
1328         entry = dma_entry_alloc();
1329         if (!entry)
1330                 return;
1331
1332         entry->dev       = dev;
1333         entry->type      = dma_debug_page;
1334         entry->pfn       = page_to_pfn(page);
1335         entry->offset    = offset,
1336         entry->dev_addr  = dma_addr;
1337         entry->size      = size;
1338         entry->direction = direction;
1339         entry->map_err_type = MAP_ERR_NOT_CHECKED;
1340
1341         if (map_single)
1342                 entry->type = dma_debug_single;
1343
1344         check_for_stack(dev, page, offset);
1345
1346         if (!PageHighMem(page)) {
1347                 void *addr = page_address(page) + offset;
1348
1349                 check_for_illegal_area(dev, addr, size);
1350         }
1351
1352         add_dma_entry(entry);
1353 }
1354 EXPORT_SYMBOL(debug_dma_map_page);
1355
1356 void debug_dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
1357 {
1358         struct dma_debug_entry ref;
1359         struct dma_debug_entry *entry;
1360         struct hash_bucket *bucket;
1361         unsigned long flags;
1362
1363         if (unlikely(dma_debug_disabled()))
1364                 return;
1365
1366         ref.dev = dev;
1367         ref.dev_addr = dma_addr;
1368         bucket = get_hash_bucket(&ref, &flags);
1369
1370         list_for_each_entry(entry, &bucket->list, list) {
1371                 if (!exact_match(&ref, entry))
1372                         continue;
1373
1374                 /*
1375                  * The same physical address can be mapped multiple
1376                  * times. Without a hardware IOMMU this results in the
1377                  * same device addresses being put into the dma-debug
1378                  * hash multiple times too. This can result in false
1379                  * positives being reported. Therefore we implement a
1380                  * best-fit algorithm here which updates the first entry
1381                  * from the hash which fits the reference value and is
1382                  * not currently listed as being checked.
1383                  */
1384                 if (entry->map_err_type == MAP_ERR_NOT_CHECKED) {
1385                         entry->map_err_type = MAP_ERR_CHECKED;
1386                         break;
1387                 }
1388         }
1389
1390         put_hash_bucket(bucket, &flags);
1391 }
1392 EXPORT_SYMBOL(debug_dma_mapping_error);
1393
1394 void debug_dma_unmap_page(struct device *dev, dma_addr_t addr,
1395                           size_t size, int direction, bool map_single)
1396 {
1397         struct dma_debug_entry ref = {
1398                 .type           = dma_debug_page,
1399                 .dev            = dev,
1400                 .dev_addr       = addr,
1401                 .size           = size,
1402                 .direction      = direction,
1403         };
1404
1405         if (unlikely(dma_debug_disabled()))
1406                 return;
1407
1408         if (map_single)
1409                 ref.type = dma_debug_single;
1410
1411         check_unmap(&ref);
1412 }
1413 EXPORT_SYMBOL(debug_dma_unmap_page);
1414
1415 void debug_dma_map_sg(struct device *dev, struct scatterlist *sg,
1416                       int nents, int mapped_ents, int direction)
1417 {
1418         struct dma_debug_entry *entry;
1419         struct scatterlist *s;
1420         int i;
1421
1422         if (unlikely(dma_debug_disabled()))
1423                 return;
1424
1425         for_each_sg(sg, s, mapped_ents, i) {
1426                 entry = dma_entry_alloc();
1427                 if (!entry)
1428                         return;
1429
1430                 entry->type           = dma_debug_sg;
1431                 entry->dev            = dev;
1432                 entry->pfn            = page_to_pfn(sg_page(s));
1433                 entry->offset         = s->offset,
1434                 entry->size           = sg_dma_len(s);
1435                 entry->dev_addr       = sg_dma_address(s);
1436                 entry->direction      = direction;
1437                 entry->sg_call_ents   = nents;
1438                 entry->sg_mapped_ents = mapped_ents;
1439
1440                 check_for_stack(dev, sg_page(s), s->offset);
1441
1442                 if (!PageHighMem(sg_page(s))) {
1443                         check_for_illegal_area(dev, sg_virt(s), sg_dma_len(s));
1444                 }
1445
1446                 check_sg_segment(dev, s);
1447
1448                 add_dma_entry(entry);
1449         }
1450 }
1451 EXPORT_SYMBOL(debug_dma_map_sg);
1452
1453 static int get_nr_mapped_entries(struct device *dev,
1454                                  struct dma_debug_entry *ref)
1455 {
1456         struct dma_debug_entry *entry;
1457         struct hash_bucket *bucket;
1458         unsigned long flags;
1459         int mapped_ents;
1460
1461         bucket       = get_hash_bucket(ref, &flags);
1462         entry        = bucket_find_exact(bucket, ref);
1463         mapped_ents  = 0;
1464
1465         if (entry)
1466                 mapped_ents = entry->sg_mapped_ents;
1467         put_hash_bucket(bucket, &flags);
1468
1469         return mapped_ents;
1470 }
1471
1472 void debug_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
1473                         int nelems, int dir)
1474 {
1475         struct scatterlist *s;
1476         int mapped_ents = 0, i;
1477
1478         if (unlikely(dma_debug_disabled()))
1479                 return;
1480
1481         for_each_sg(sglist, s, nelems, i) {
1482
1483                 struct dma_debug_entry ref = {
1484                         .type           = dma_debug_sg,
1485                         .dev            = dev,
1486                         .pfn            = page_to_pfn(sg_page(s)),
1487                         .offset         = s->offset,
1488                         .dev_addr       = sg_dma_address(s),
1489                         .size           = sg_dma_len(s),
1490                         .direction      = dir,
1491                         .sg_call_ents   = nelems,
1492                 };
1493
1494                 if (mapped_ents && i >= mapped_ents)
1495                         break;
1496
1497                 if (!i)
1498                         mapped_ents = get_nr_mapped_entries(dev, &ref);
1499
1500                 check_unmap(&ref);
1501         }
1502 }
1503 EXPORT_SYMBOL(debug_dma_unmap_sg);
1504
1505 void debug_dma_alloc_coherent(struct device *dev, size_t size,
1506                               dma_addr_t dma_addr, void *virt)
1507 {
1508         struct dma_debug_entry *entry;
1509
1510         if (unlikely(dma_debug_disabled()))
1511                 return;
1512
1513         if (unlikely(virt == NULL))
1514                 return;
1515
1516         /* handle vmalloc and linear addresses */
1517         if (!is_vmalloc_addr(virt) && !virt_addr_valid(virt))
1518                 return;
1519
1520         entry = dma_entry_alloc();
1521         if (!entry)
1522                 return;
1523
1524         entry->type      = dma_debug_coherent;
1525         entry->dev       = dev;
1526         entry->offset    = offset_in_page(virt);
1527         entry->size      = size;
1528         entry->dev_addr  = dma_addr;
1529         entry->direction = DMA_BIDIRECTIONAL;
1530
1531         if (is_vmalloc_addr(virt))
1532                 entry->pfn = vmalloc_to_pfn(virt);
1533         else
1534                 entry->pfn = page_to_pfn(virt_to_page(virt));
1535
1536         add_dma_entry(entry);
1537 }
1538 EXPORT_SYMBOL(debug_dma_alloc_coherent);
1539
1540 void debug_dma_free_coherent(struct device *dev, size_t size,
1541                          void *virt, dma_addr_t addr)
1542 {
1543         struct dma_debug_entry ref = {
1544                 .type           = dma_debug_coherent,
1545                 .dev            = dev,
1546                 .offset         = offset_in_page(virt),
1547                 .dev_addr       = addr,
1548                 .size           = size,
1549                 .direction      = DMA_BIDIRECTIONAL,
1550         };
1551
1552         /* handle vmalloc and linear addresses */
1553         if (!is_vmalloc_addr(virt) && !virt_addr_valid(virt))
1554                 return;
1555
1556         if (is_vmalloc_addr(virt))
1557                 ref.pfn = vmalloc_to_pfn(virt);
1558         else
1559                 ref.pfn = page_to_pfn(virt_to_page(virt));
1560
1561         if (unlikely(dma_debug_disabled()))
1562                 return;
1563
1564         check_unmap(&ref);
1565 }
1566 EXPORT_SYMBOL(debug_dma_free_coherent);
1567
1568 void debug_dma_map_resource(struct device *dev, phys_addr_t addr, size_t size,
1569                             int direction, dma_addr_t dma_addr)
1570 {
1571         struct dma_debug_entry *entry;
1572
1573         if (unlikely(dma_debug_disabled()))
1574                 return;
1575
1576         entry = dma_entry_alloc();
1577         if (!entry)
1578                 return;
1579
1580         entry->type             = dma_debug_resource;
1581         entry->dev              = dev;
1582         entry->pfn              = PHYS_PFN(addr);
1583         entry->offset           = offset_in_page(addr);
1584         entry->size             = size;
1585         entry->dev_addr         = dma_addr;
1586         entry->direction        = direction;
1587         entry->map_err_type     = MAP_ERR_NOT_CHECKED;
1588
1589         add_dma_entry(entry);
1590 }
1591 EXPORT_SYMBOL(debug_dma_map_resource);
1592
1593 void debug_dma_unmap_resource(struct device *dev, dma_addr_t dma_addr,
1594                               size_t size, int direction)
1595 {
1596         struct dma_debug_entry ref = {
1597                 .type           = dma_debug_resource,
1598                 .dev            = dev,
1599                 .dev_addr       = dma_addr,
1600                 .size           = size,
1601                 .direction      = direction,
1602         };
1603
1604         if (unlikely(dma_debug_disabled()))
1605                 return;
1606
1607         check_unmap(&ref);
1608 }
1609 EXPORT_SYMBOL(debug_dma_unmap_resource);
1610
1611 void debug_dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_handle,
1612                                    size_t size, int direction)
1613 {
1614         struct dma_debug_entry ref;
1615
1616         if (unlikely(dma_debug_disabled()))
1617                 return;
1618
1619         ref.type         = dma_debug_single;
1620         ref.dev          = dev;
1621         ref.dev_addr     = dma_handle;
1622         ref.size         = size;
1623         ref.direction    = direction;
1624         ref.sg_call_ents = 0;
1625
1626         check_sync(dev, &ref, true);
1627 }
1628 EXPORT_SYMBOL(debug_dma_sync_single_for_cpu);
1629
1630 void debug_dma_sync_single_for_device(struct device *dev,
1631                                       dma_addr_t dma_handle, size_t size,
1632                                       int direction)
1633 {
1634         struct dma_debug_entry ref;
1635
1636         if (unlikely(dma_debug_disabled()))
1637                 return;
1638
1639         ref.type         = dma_debug_single;
1640         ref.dev          = dev;
1641         ref.dev_addr     = dma_handle;
1642         ref.size         = size;
1643         ref.direction    = direction;
1644         ref.sg_call_ents = 0;
1645
1646         check_sync(dev, &ref, false);
1647 }
1648 EXPORT_SYMBOL(debug_dma_sync_single_for_device);
1649
1650 void debug_dma_sync_single_range_for_cpu(struct device *dev,
1651                                          dma_addr_t dma_handle,
1652                                          unsigned long offset, size_t size,
1653                                          int direction)
1654 {
1655         struct dma_debug_entry ref;
1656
1657         if (unlikely(dma_debug_disabled()))
1658                 return;
1659
1660         ref.type         = dma_debug_single;
1661         ref.dev          = dev;
1662         ref.dev_addr     = dma_handle;
1663         ref.size         = offset + size;
1664         ref.direction    = direction;
1665         ref.sg_call_ents = 0;
1666
1667         check_sync(dev, &ref, true);
1668 }
1669 EXPORT_SYMBOL(debug_dma_sync_single_range_for_cpu);
1670
1671 void debug_dma_sync_single_range_for_device(struct device *dev,
1672                                             dma_addr_t dma_handle,
1673                                             unsigned long offset,
1674                                             size_t size, int direction)
1675 {
1676         struct dma_debug_entry ref;
1677
1678         if (unlikely(dma_debug_disabled()))
1679                 return;
1680
1681         ref.type         = dma_debug_single;
1682         ref.dev          = dev;
1683         ref.dev_addr     = dma_handle;
1684         ref.size         = offset + size;
1685         ref.direction    = direction;
1686         ref.sg_call_ents = 0;
1687
1688         check_sync(dev, &ref, false);
1689 }
1690 EXPORT_SYMBOL(debug_dma_sync_single_range_for_device);
1691
1692 void debug_dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
1693                                int nelems, int direction)
1694 {
1695         struct scatterlist *s;
1696         int mapped_ents = 0, i;
1697
1698         if (unlikely(dma_debug_disabled()))
1699                 return;
1700
1701         for_each_sg(sg, s, nelems, i) {
1702
1703                 struct dma_debug_entry ref = {
1704                         .type           = dma_debug_sg,
1705                         .dev            = dev,
1706                         .pfn            = page_to_pfn(sg_page(s)),
1707                         .offset         = s->offset,
1708                         .dev_addr       = sg_dma_address(s),
1709                         .size           = sg_dma_len(s),
1710                         .direction      = direction,
1711                         .sg_call_ents   = nelems,
1712                 };
1713
1714                 if (!i)
1715                         mapped_ents = get_nr_mapped_entries(dev, &ref);
1716
1717                 if (i >= mapped_ents)
1718                         break;
1719
1720                 check_sync(dev, &ref, true);
1721         }
1722 }
1723 EXPORT_SYMBOL(debug_dma_sync_sg_for_cpu);
1724
1725 void debug_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
1726                                   int nelems, int direction)
1727 {
1728         struct scatterlist *s;
1729         int mapped_ents = 0, i;
1730
1731         if (unlikely(dma_debug_disabled()))
1732                 return;
1733
1734         for_each_sg(sg, s, nelems, i) {
1735
1736                 struct dma_debug_entry ref = {
1737                         .type           = dma_debug_sg,
1738                         .dev            = dev,
1739                         .pfn            = page_to_pfn(sg_page(s)),
1740                         .offset         = s->offset,
1741                         .dev_addr       = sg_dma_address(s),
1742                         .size           = sg_dma_len(s),
1743                         .direction      = direction,
1744                         .sg_call_ents   = nelems,
1745                 };
1746                 if (!i)
1747                         mapped_ents = get_nr_mapped_entries(dev, &ref);
1748
1749                 if (i >= mapped_ents)
1750                         break;
1751
1752                 check_sync(dev, &ref, false);
1753         }
1754 }
1755 EXPORT_SYMBOL(debug_dma_sync_sg_for_device);
1756
1757 static int __init dma_debug_driver_setup(char *str)
1758 {
1759         int i;
1760
1761         for (i = 0; i < NAME_MAX_LEN - 1; ++i, ++str) {
1762                 current_driver_name[i] = *str;
1763                 if (*str == 0)
1764                         break;
1765         }
1766
1767         if (current_driver_name[0])
1768                 pr_info("DMA-API: enable driver filter for driver [%s]\n",
1769                         current_driver_name);
1770
1771
1772         return 1;
1773 }
1774 __setup("dma_debug_driver=", dma_debug_driver_setup);