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 #define pr_fmt(fmt)     "DMA-API: " fmt
  21
  22 #include <linux/sched/task_stack.h>
  23 #include <linux/scatterlist.h>
  24 #include <linux/dma-mapping.h>
  25 #include <linux/sched/task.h>
  26 #include <linux/stacktrace.h>
  27 #include <linux/dma-debug.h>
  28 #include <linux/spinlock.h>
  29 #include <linux/vmalloc.h>
  30 #include <linux/debugfs.h>
  31 #include <linux/uaccess.h>
  32 #include <linux/export.h>
  33 #include <linux/device.h>
  34 #include <linux/types.h>
  35 #include <linux/sched.h>
  36 #include <linux/ctype.h>
  37 #include <linux/list.h>
  38 #include <linux/slab.h>
  39
  40 #include <asm/sections.h>
  41
  42 #define HASH_SIZE       1024ULL
  43 #define HASH_FN_SHIFT   13
  44 #define HASH_FN_MASK    (HASH_SIZE - 1)
  45
  46 #define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16)
  47 /* If the pool runs out, add this many new entries at once */
  48 #define DMA_DEBUG_DYNAMIC_ENTRIES (PAGE_SIZE / sizeof(struct dma_debug_entry))
  49
  50 enum {
  51         dma_debug_single,
  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 *nr_total_entries_dent __read_mostly;
 146 static struct dentry *filter_dent           __read_mostly;
 147
 148 /* per-driver filter related state */
 149
 150 #define NAME_MAX_LEN    64
 151
 152 static char                  current_driver_name[NAME_MAX_LEN] __read_mostly;
 153 static struct device_driver *current_driver                    __read_mostly;
 154
 155 static DEFINE_RWLOCK(driver_name_lock);
 156
 157 static const char *const maperr2str[] = {
 158         [MAP_ERR_CHECK_NOT_APPLICABLE] = "dma map error check not applicable",
 159         [MAP_ERR_NOT_CHECKED] = "dma map error not checked",
 160         [MAP_ERR_CHECKED] = "dma map error checked",
 161 };
 162
 163 static const char *type2name[5] = { "single", "page",
 164                                     "scather-gather", "coherent",
 165                                     "resource" };
 166
 167 static const char *dir2name[4] = { "DMA_BIDIRECTIONAL", "DMA_TO_DEVICE",
 168                                    "DMA_FROM_DEVICE", "DMA_NONE" };
 169
 170 /*
 171  * The access to some variables in this macro is racy. We can't use atomic_t
 172  * here because all these variables are exported to debugfs. Some of them even
 173  * writeable. This is also the reason why a lock won't help much. But anyway,
 174  * the races are no big deal. Here is why:
 175  *
 176  *   error_count: the addition is racy, but the worst thing that can happen is
 177  *                that we don't count some errors
 178  *   show_num_errors: the subtraction is racy. Also no big deal because in
 179  *                    worst case this will result in one warning more in the
 180  *                    system log than the user configured. This variable is
 181  *                    writeable via debugfs.
 182  */
 183 static inline void dump_entry_trace(struct dma_debug_entry *entry)
 184 {
 185 #ifdef CONFIG_STACKTRACE
 186         if (entry) {
 187                 pr_warning("Mapped at:\n");
 188                 print_stack_trace(&entry->stacktrace, 0);
 189         }
 190 #endif
 191 }
 192
 193 static bool driver_filter(struct device *dev)
 194 {
 195         struct device_driver *drv;
 196         unsigned long flags;
 197         bool ret;
 198
 199         /* driver filter off */
 200         if (likely(!current_driver_name[0]))
 201                 return true;
 202
 203         /* driver filter on and initialized */
 204         if (current_driver && dev && dev->driver == current_driver)
 205                 return true;
 206
 207         /* driver filter on, but we can't filter on a NULL device... */
 208         if (!dev)
 209                 return false;
 210
 211         if (current_driver || !current_driver_name[0])
 212                 return false;
 213
 214         /* driver filter on but not yet initialized */
 215         drv = dev->driver;
 216         if (!drv)
 217                 return false;
 218
 219         /* lock to protect against change of current_driver_name */
 220         read_lock_irqsave(&driver_name_lock, flags);
 221
 222         ret = false;
 223         if (drv->name &&
 224             strncmp(current_driver_name, drv->name, NAME_MAX_LEN - 1) == 0) {
 225                 current_driver = drv;
 226                 ret = true;
 227         }
 228
 229         read_unlock_irqrestore(&driver_name_lock, flags);
 230
 231         return ret;
 232 }
 233
 234 #define err_printk(dev, entry, format, arg...) do {                     \
 235                 error_count += 1;                                       \
 236                 if (driver_filter(dev) &&                               \
 237                     (show_all_errors || show_num_errors > 0)) {         \
 238                         WARN(1, pr_fmt("%s %s: ") format,               \
 239                              dev ? dev_driver_string(dev) : "NULL",     \
 240                              dev ? dev_name(dev) : "NULL", ## arg);     \
 241                         dump_entry_trace(entry);                        \
 242                 }                                                       \
 243                 if (!show_all_errors && show_num_errors > 0)            \
 244                         show_num_errors -= 1;                           \
 245         } while (0);
 246
 247 /*
 248  * Hash related functions
 249  *
 250  * Every DMA-API request is saved into a struct dma_debug_entry. To
 251  * have quick access to these structs they are stored into a hash.
 252  */
 253 static int hash_fn(struct dma_debug_entry *entry)
 254 {
 255         /*
 256          * Hash function is based on the dma address.
 257          * We use bits 20-27 here as the index into the hash
 258          */
 259         return (entry->dev_addr >> HASH_FN_SHIFT) & HASH_FN_MASK;
 260 }
 261
 262 /*
 263  * Request exclusive access to a hash bucket for a given dma_debug_entry.
 264  */
 265 static struct hash_bucket *get_hash_bucket(struct dma_debug_entry *entry,
 266                                            unsigned long *flags)
 267         __acquires(&dma_entry_hash[idx].lock)
 268 {
 269         int idx = hash_fn(entry);
 270         unsigned long __flags;
 271
 272         spin_lock_irqsave(&dma_entry_hash[idx].lock, __flags);
 273         *flags = __flags;
 274         return &dma_entry_hash[idx];
 275 }
 276
 277 /*
 278  * Give up exclusive access to the hash bucket
 279  */
 280 static void put_hash_bucket(struct hash_bucket *bucket,
 281                             unsigned long *flags)
 282         __releases(&bucket->lock)
 283 {
 284         unsigned long __flags = *flags;
 285
 286         spin_unlock_irqrestore(&bucket->lock, __flags);
 287 }
 288
 289 static bool exact_match(struct dma_debug_entry *a, struct dma_debug_entry *b)
 290 {
 291         return ((a->dev_addr == b->dev_addr) &&
 292                 (a->dev == b->dev)) ? true : false;
 293 }
 294
 295 static bool containing_match(struct dma_debug_entry *a,
 296                              struct dma_debug_entry *b)
 297 {
 298         if (a->dev != b->dev)
 299                 return false;
 300
 301         if ((b->dev_addr <= a->dev_addr) &&
 302             ((b->dev_addr + b->size) >= (a->dev_addr + a->size)))
 303                 return true;
 304
 305         return false;
 306 }
 307
 308 /*
 309  * Search a given entry in the hash bucket list
 310  */
 311 static struct dma_debug_entry *__hash_bucket_find(struct hash_bucket *bucket,
 312                                                   struct dma_debug_entry *ref,
 313                                                   match_fn match)
 314 {
 315         struct dma_debug_entry *entry, *ret = NULL;
 316         int matches = 0, match_lvl, last_lvl = -1;
 317
 318         list_for_each_entry(entry, &bucket->list, list) {
 319                 if (!match(ref, entry))
 320                         continue;
 321
 322                 /*
 323                  * Some drivers map the same physical address multiple
 324                  * times. Without a hardware IOMMU this results in the
 325                  * same device addresses being put into the dma-debug
 326                  * hash multiple times too. This can result in false
 327                  * positives being reported. Therefore we implement a
 328                  * best-fit algorithm here which returns the entry from
 329                  * the hash which fits best to the reference value
 330                  * instead of the first-fit.
 331                  */
 332                 matches += 1;
 333                 match_lvl = 0;
 334                 entry->size         == ref->size         ? ++match_lvl : 0;
 335                 entry->type         == ref->type         ? ++match_lvl : 0;
 336                 entry->direction    == ref->direction    ? ++match_lvl : 0;
 337                 entry->sg_call_ents == ref->sg_call_ents ? ++match_lvl : 0;
 338
 339                 if (match_lvl == 4) {
 340                         /* perfect-fit - return the result */
 341                         return entry;
 342                 } else if (match_lvl > last_lvl) {
 343                         /*
 344                          * We found an entry that fits better then the
 345                          * previous one or it is the 1st match.
 346                          */
 347                         last_lvl = match_lvl;
 348                         ret      = entry;
 349                 }
 350         }
 351
 352         /*
 353          * If we have multiple matches but no perfect-fit, just return
 354          * NULL.
 355          */
 356         ret = (matches == 1) ? ret : NULL;
 357
 358         return ret;
 359 }
 360
 361 static struct dma_debug_entry *bucket_find_exact(struct hash_bucket *bucket,
 362                                                  struct dma_debug_entry *ref)
 363 {
 364         return __hash_bucket_find(bucket, ref, exact_match);
 365 }
 366
 367 static struct dma_debug_entry *bucket_find_contain(struct hash_bucket **bucket,
 368                                                    struct dma_debug_entry *ref,
 369                                                    unsigned long *flags)
 370 {
 371
 372         unsigned int max_range = dma_get_max_seg_size(ref->dev);
 373         struct dma_debug_entry *entry, index = *ref;
 374         unsigned int range = 0;
 375
 376         while (range <= max_range) {
 377                 entry = __hash_bucket_find(*bucket, ref, containing_match);
 378
 379                 if (entry)
 380                         return entry;
 381
 382                 /*
 383                  * Nothing found, go back a hash bucket
 384                  */
 385                 put_hash_bucket(*bucket, flags);
 386                 range          += (1 << HASH_FN_SHIFT);
 387                 index.dev_addr -= (1 << HASH_FN_SHIFT);
 388                 *bucket = get_hash_bucket(&index, flags);
 389         }
 390
 391         return NULL;
 392 }
 393
 394 /*
 395  * Add an entry to a hash bucket
 396  */
 397 static void hash_bucket_add(struct hash_bucket *bucket,
 398                             struct dma_debug_entry *entry)
 399 {
 400         list_add_tail(&entry->list, &bucket->list);
 401 }
 402
 403 /*
 404  * Remove entry from a hash bucket list
 405  */
 406 static void hash_bucket_del(struct dma_debug_entry *entry)
 407 {
 408         list_del(&entry->list);
 409 }
 410
 411 static unsigned long long phys_addr(struct dma_debug_entry *entry)
 412 {
 413         if (entry->type == dma_debug_resource)
 414                 return __pfn_to_phys(entry->pfn) + entry->offset;
 415
 416         return page_to_phys(pfn_to_page(entry->pfn)) + entry->offset;
 417 }
 418
 419 /*
 420  * Dump mapping entries for debugging purposes
 421  */
 422 void debug_dma_dump_mappings(struct device *dev)
 423 {
 424         int idx;
 425
 426         for (idx = 0; idx < HASH_SIZE; idx++) {
 427                 struct hash_bucket *bucket = &dma_entry_hash[idx];
 428                 struct dma_debug_entry *entry;
 429                 unsigned long flags;
 430
 431                 spin_lock_irqsave(&bucket->lock, flags);
 432
 433                 list_for_each_entry(entry, &bucket->list, list) {
 434                         if (!dev || dev == entry->dev) {
 435                                 dev_info(entry->dev,
 436                                          "%s idx %d P=%Lx N=%lx D=%Lx L=%Lx %s %s\n",
 437                                          type2name[entry->type], idx,
 438                                          phys_addr(entry), entry->pfn,
 439                                          entry->dev_addr, entry->size,
 440                                          dir2name[entry->direction],
 441                                          maperr2str[entry->map_err_type]);
 442                         }
 443                 }
 444
 445                 spin_unlock_irqrestore(&bucket->lock, flags);
 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                   pr_fmt("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                    "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("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 int dma_debug_create_entries(gfp_t gfp)
 648 {
 649         struct dma_debug_entry *entry;
 650         int i;
 651
 652         entry = (void *)get_zeroed_page(gfp);
 653         if (!entry)
 654                 return -ENOMEM;
 655
 656         for (i = 0; i < DMA_DEBUG_DYNAMIC_ENTRIES; i++)
 657                 list_add_tail(&entry[i].list, &free_entries);
 658
 659         num_free_entries += DMA_DEBUG_DYNAMIC_ENTRIES;
 660         nr_total_entries += DMA_DEBUG_DYNAMIC_ENTRIES;
 661
 662         return 0;
 663 }
 664
 665 static struct dma_debug_entry *__dma_entry_alloc(void)
 666 {
 667         struct dma_debug_entry *entry;
 668
 669         entry = list_entry(free_entries.next, struct dma_debug_entry, list);
 670         list_del(&entry->list);
 671         memset(entry, 0, sizeof(*entry));
 672
 673         num_free_entries -= 1;
 674         if (num_free_entries < min_free_entries)
 675                 min_free_entries = num_free_entries;
 676
 677         return entry;
 678 }
 679
 680 void __dma_entry_alloc_check_leak(void)
 681 {
 682         u32 tmp = nr_total_entries % nr_prealloc_entries;
 683
 684         /* Shout each time we tick over some multiple of the initial pool */
 685         if (tmp < DMA_DEBUG_DYNAMIC_ENTRIES) {
 686                 pr_info("dma_debug_entry pool grown to %u (%u00%%)\n",
 687                         nr_total_entries,
 688                         (nr_total_entries / nr_prealloc_entries));
 689         }
 690 }
 691
 692 /* struct dma_entry allocator
 693  *
 694  * The next two functions implement the allocator for
 695  * struct dma_debug_entries.
 696  */
 697 static struct dma_debug_entry *dma_entry_alloc(void)
 698 {
 699         struct dma_debug_entry *entry;
 700         unsigned long flags;
 701
 702         spin_lock_irqsave(&free_entries_lock, flags);
 703         if (num_free_entries == 0) {
 704                 if (dma_debug_create_entries(GFP_ATOMIC)) {
 705                         global_disable = true;
 706                         spin_unlock_irqrestore(&free_entries_lock, flags);
 707                         pr_err("debugging out of memory - disabling\n");
 708                         return NULL;
 709                 }
 710                 __dma_entry_alloc_check_leak();
 711         }
 712
 713         entry = __dma_entry_alloc();
 714
 715         spin_unlock_irqrestore(&free_entries_lock, flags);
 716
 717 #ifdef CONFIG_STACKTRACE
 718         entry->stacktrace.max_entries = DMA_DEBUG_STACKTRACE_ENTRIES;
 719         entry->stacktrace.entries = entry->st_entries;
 720         entry->stacktrace.skip = 2;
 721         save_stack_trace(&entry->stacktrace);
 722 #endif
 723
 724         return entry;
 725 }
 726
 727 static void dma_entry_free(struct dma_debug_entry *entry)
 728 {
 729         unsigned long flags;
 730
 731         active_cacheline_remove(entry);
 732
 733         /*
 734          * add to beginning of the list - this way the entries are
 735          * more likely cache hot when they are reallocated.
 736          */
 737         spin_lock_irqsave(&free_entries_lock, flags);
 738         list_add(&entry->list, &free_entries);
 739         num_free_entries += 1;
 740         spin_unlock_irqrestore(&free_entries_lock, flags);
 741 }
 742
 743 /*
 744  * DMA-API debugging init code
 745  *
 746  * The init code does two things:
 747  *   1. Initialize core data structures
 748  *   2. Preallocate a given number of dma_debug_entry structs
 749  */
 750
 751 static ssize_t filter_read(struct file *file, char __user *user_buf,
 752                            size_t count, loff_t *ppos)
 753 {
 754         char buf[NAME_MAX_LEN + 1];
 755         unsigned long flags;
 756         int len;
 757
 758         if (!current_driver_name[0])
 759                 return 0;
 760
 761         /*
 762          * We can't copy to userspace directly because current_driver_name can
 763          * only be read under the driver_name_lock with irqs disabled. So
 764          * create a temporary copy first.
 765          */
 766         read_lock_irqsave(&driver_name_lock, flags);
 767         len = scnprintf(buf, NAME_MAX_LEN + 1, "%s\n", current_driver_name);
 768         read_unlock_irqrestore(&driver_name_lock, flags);
 769
 770         return simple_read_from_buffer(user_buf, count, ppos, buf, len);
 771 }
 772
 773 static ssize_t filter_write(struct file *file, const char __user *userbuf,
 774                             size_t count, loff_t *ppos)
 775 {
 776         char buf[NAME_MAX_LEN];
 777         unsigned long flags;
 778         size_t len;
 779         int i;
 780
 781         /*
 782          * We can't copy from userspace directly. Access to
 783          * current_driver_name is protected with a write_lock with irqs
 784          * disabled. Since copy_from_user can fault and may sleep we
 785          * need to copy to temporary buffer first
 786          */
 787         len = min(count, (size_t)(NAME_MAX_LEN - 1));
 788         if (copy_from_user(buf, userbuf, len))
 789                 return -EFAULT;
 790
 791         buf[len] = 0;
 792
 793         write_lock_irqsave(&driver_name_lock, flags);
 794
 795         /*
 796          * Now handle the string we got from userspace very carefully.
 797          * The rules are:
 798          *         - only use the first token we got
 799          *         - token delimiter is everything looking like a space
 800          *           character (' ', '\n', '\t' ...)
 801          *
 802          */
 803         if (!isalnum(buf[0])) {
 804                 /*
 805                  * If the first character userspace gave us is not
 806                  * alphanumerical then assume the filter should be
 807                  * switched off.
 808                  */
 809                 if (current_driver_name[0])
 810                         pr_info("switching off dma-debug driver filter\n");
 811                 current_driver_name[0] = 0;
 812                 current_driver = NULL;
 813                 goto out_unlock;
 814         }
 815
 816         /*
 817          * Now parse out the first token and use it as the name for the
 818          * driver to filter for.
 819          */
 820         for (i = 0; i < NAME_MAX_LEN - 1; ++i) {
 821                 current_driver_name[i] = buf[i];
 822                 if (isspace(buf[i]) || buf[i] == ' ' || buf[i] == 0)
 823                         break;
 824         }
 825         current_driver_name[i] = 0;
 826         current_driver = NULL;
 827
 828         pr_info("enable driver filter for driver [%s]\n",
 829                 current_driver_name);
 830
 831 out_unlock:
 832         write_unlock_irqrestore(&driver_name_lock, flags);
 833
 834         return count;
 835 }
 836
 837 static const struct file_operations filter_fops = {
 838         .read  = filter_read,
 839         .write = filter_write,
 840         .llseek = default_llseek,
 841 };
 842
 843 static int dma_debug_fs_init(void)
 844 {
 845         dma_debug_dent = debugfs_create_dir("dma-api", NULL);
 846         if (!dma_debug_dent) {
 847                 pr_err("can not create debugfs directory\n");
 848                 return -ENOMEM;
 849         }
 850
 851         global_disable_dent = debugfs_create_bool("disabled", 0444,
 852                         dma_debug_dent,
 853                         &global_disable);
 854         if (!global_disable_dent)
 855                 goto out_err;
 856
 857         error_count_dent = debugfs_create_u32("error_count", 0444,
 858                         dma_debug_dent, &error_count);
 859         if (!error_count_dent)
 860                 goto out_err;
 861
 862         show_all_errors_dent = debugfs_create_u32("all_errors", 0644,
 863                         dma_debug_dent,
 864                         &show_all_errors);
 865         if (!show_all_errors_dent)
 866                 goto out_err;
 867
 868         show_num_errors_dent = debugfs_create_u32("num_errors", 0644,
 869                         dma_debug_dent,
 870                         &show_num_errors);
 871         if (!show_num_errors_dent)
 872                 goto out_err;
 873
 874         num_free_entries_dent = debugfs_create_u32("num_free_entries", 0444,
 875                         dma_debug_dent,
 876                         &num_free_entries);
 877         if (!num_free_entries_dent)
 878                 goto out_err;
 879
 880         min_free_entries_dent = debugfs_create_u32("min_free_entries", 0444,
 881                         dma_debug_dent,
 882                         &min_free_entries);
 883         if (!min_free_entries_dent)
 884                 goto out_err;
 885
 886         nr_total_entries_dent = debugfs_create_u32("nr_total_entries", 0444,
 887                         dma_debug_dent,
 888                         &nr_total_entries);
 889         if (!nr_total_entries_dent)
 890                 goto out_err;
 891
 892         filter_dent = debugfs_create_file("driver_filter", 0644,
 893                                           dma_debug_dent, NULL, &filter_fops);
 894         if (!filter_dent)
 895                 goto out_err;
 896
 897         return 0;
 898
 899 out_err:
 900         debugfs_remove_recursive(dma_debug_dent);
 901
 902         return -ENOMEM;
 903 }
 904
 905 static int device_dma_allocations(struct device *dev, struct dma_debug_entry **out_entry)
 906 {
 907         struct dma_debug_entry *entry;
 908         unsigned long flags;
 909         int count = 0, i;
 910
 911         for (i = 0; i < HASH_SIZE; ++i) {
 912                 spin_lock_irqsave(&dma_entry_hash[i].lock, flags);
 913                 list_for_each_entry(entry, &dma_entry_hash[i].list, list) {
 914                         if (entry->dev == dev) {
 915                                 count += 1;
 916                                 *out_entry = entry;
 917                         }
 918                 }
 919                 spin_unlock_irqrestore(&dma_entry_hash[i].lock, flags);
 920         }
 921
 922         return count;
 923 }
 924
 925 static int dma_debug_device_change(struct notifier_block *nb, unsigned long action, void *data)
 926 {
 927         struct device *dev = data;
 928         struct dma_debug_entry *uninitialized_var(entry);
 929         int count;
 930
 931         if (dma_debug_disabled())
 932                 return 0;
 933
 934         switch (action) {
 935         case BUS_NOTIFY_UNBOUND_DRIVER:
 936                 count = device_dma_allocations(dev, &entry);
 937                 if (count == 0)
 938                         break;
 939                 err_printk(dev, entry, "device driver has pending "
 940                                 "DMA allocations while released from device "
 941                                 "[count=%d]\n"
 942                                 "One of leaked entries details: "
 943                                 "[device address=0x%016llx] [size=%llu bytes] "
 944                                 "[mapped with %s] [mapped as %s]\n",
 945                         count, entry->dev_addr, entry->size,
 946                         dir2name[entry->direction], type2name[entry->type]);
 947                 break;
 948         default:
 949                 break;
 950         }
 951
 952         return 0;
 953 }
 954
 955 void dma_debug_add_bus(struct bus_type *bus)
 956 {
 957         struct notifier_block *nb;
 958
 959         if (dma_debug_disabled())
 960                 return;
 961
 962         nb = kzalloc(sizeof(struct notifier_block), GFP_KERNEL);
 963         if (nb == NULL) {
 964                 pr_err("dma_debug_add_bus: out of memory\n");
 965                 return;
 966         }
 967
 968         nb->notifier_call = dma_debug_device_change;
 969
 970         bus_register_notifier(bus, nb);
 971 }
 972
 973 static int dma_debug_init(void)
 974 {
 975         int i, nr_pages;
 976
 977         /* Do not use dma_debug_initialized here, since we really want to be
 978          * called to set dma_debug_initialized
 979          */
 980         if (global_disable)
 981                 return 0;
 982
 983         for (i = 0; i < HASH_SIZE; ++i) {
 984                 INIT_LIST_HEAD(&dma_entry_hash[i].list);
 985                 spin_lock_init(&dma_entry_hash[i].lock);
 986         }
 987
 988         if (dma_debug_fs_init() != 0) {
 989                 pr_err("error creating debugfs entries - disabling\n");
 990                 global_disable = true;
 991
 992                 return 0;
 993         }
 994
 995         nr_pages = DIV_ROUND_UP(nr_prealloc_entries, DMA_DEBUG_DYNAMIC_ENTRIES);
 996         for (i = 0; i < nr_pages; ++i)
 997                 dma_debug_create_entries(GFP_KERNEL);
 998         if (num_free_entries >= nr_prealloc_entries) {
 999                 pr_info("preallocated %d debug entries\n", nr_total_entries);
1000         } else if (num_free_entries > 0) {
1001                 pr_warn("%d debug entries requested but only %d allocated\n",
1002                         nr_prealloc_entries, nr_total_entries);
1003         } else {
1004                 pr_err("debugging out of memory error - disabled\n");
1005                 global_disable = true;
1006
1007                 return 0;
1008         }
1009         min_free_entries = num_free_entries;
1010
1011         dma_debug_initialized = true;
1012
1013         pr_info("debugging enabled by kernel config\n");
1014         return 0;
1015 }
1016 core_initcall(dma_debug_init);
1017
1018 static __init int dma_debug_cmdline(char *str)
1019 {
1020         if (!str)
1021                 return -EINVAL;
1022
1023         if (strncmp(str, "off", 3) == 0) {
1024                 pr_info("debugging disabled on kernel command line\n");
1025                 global_disable = true;
1026         }
1027
1028         return 0;
1029 }
1030
1031 static __init int dma_debug_entries_cmdline(char *str)
1032 {
1033         if (!str)
1034                 return -EINVAL;
1035         if (!get_option(&str, &nr_prealloc_entries))
1036                 nr_prealloc_entries = PREALLOC_DMA_DEBUG_ENTRIES;
1037         return 0;
1038 }
1039
1040 __setup("dma_debug=", dma_debug_cmdline);
1041 __setup("dma_debug_entries=", dma_debug_entries_cmdline);
1042
1043 static void check_unmap(struct dma_debug_entry *ref)
1044 {
1045         struct dma_debug_entry *entry;
1046         struct hash_bucket *bucket;
1047         unsigned long flags;
1048
1049         bucket = get_hash_bucket(ref, &flags);
1050         entry = bucket_find_exact(bucket, ref);
1051
1052         if (!entry) {
1053                 /* must drop lock before calling dma_mapping_error */
1054                 put_hash_bucket(bucket, &flags);
1055
1056                 if (dma_mapping_error(ref->dev, ref->dev_addr)) {
1057                         err_printk(ref->dev, NULL,
1058                                    "device driver tries to free an "
1059                                    "invalid DMA memory address\n");
1060                 } else {
1061                         err_printk(ref->dev, NULL,
1062                                    "device driver tries to free DMA "
1063                                    "memory it has not allocated [device "
1064                                    "address=0x%016llx] [size=%llu bytes]\n",
1065                                    ref->dev_addr, ref->size);
1066                 }
1067                 return;
1068         }
1069
1070         if (ref->size != entry->size) {
1071                 err_printk(ref->dev, entry, "device driver frees "
1072                            "DMA memory with different size "
1073                            "[device address=0x%016llx] [map size=%llu bytes] "
1074                            "[unmap size=%llu bytes]\n",
1075                            ref->dev_addr, entry->size, ref->size);
1076         }
1077
1078         if (ref->type != entry->type) {
1079                 err_printk(ref->dev, entry, "device driver frees "
1080                            "DMA memory with wrong function "
1081                            "[device address=0x%016llx] [size=%llu bytes] "
1082                            "[mapped as %s] [unmapped as %s]\n",
1083                            ref->dev_addr, ref->size,
1084                            type2name[entry->type], type2name[ref->type]);
1085         } else if ((entry->type == dma_debug_coherent) &&
1086                    (phys_addr(ref) != phys_addr(entry))) {
1087                 err_printk(ref->dev, entry, "device driver frees "
1088                            "DMA memory with different CPU address "
1089                            "[device address=0x%016llx] [size=%llu bytes] "
1090                            "[cpu alloc address=0x%016llx] "
1091                            "[cpu free address=0x%016llx]",
1092                            ref->dev_addr, ref->size,
1093                            phys_addr(entry),
1094                            phys_addr(ref));
1095         }
1096
1097         if (ref->sg_call_ents && ref->type == dma_debug_sg &&
1098             ref->sg_call_ents != entry->sg_call_ents) {
1099                 err_printk(ref->dev, entry, "device driver frees "
1100                            "DMA sg list with different entry count "
1101                            "[map count=%d] [unmap count=%d]\n",
1102                            entry->sg_call_ents, ref->sg_call_ents);
1103         }
1104
1105         /*
1106          * This may be no bug in reality - but most implementations of the
1107          * DMA API don't handle this properly, so check for it here
1108          */
1109         if (ref->direction != entry->direction) {
1110                 err_printk(ref->dev, entry, "device driver frees "
1111                            "DMA memory with different direction "
1112                            "[device address=0x%016llx] [size=%llu bytes] "
1113                            "[mapped with %s] [unmapped with %s]\n",
1114                            ref->dev_addr, ref->size,
1115                            dir2name[entry->direction],
1116                            dir2name[ref->direction]);
1117         }
1118
1119         /*
1120          * Drivers should use dma_mapping_error() to check the returned
1121          * addresses of dma_map_single() and dma_map_page().
1122          * If not, print this warning message. See Documentation/DMA-API.txt.
1123          */
1124         if (entry->map_err_type == MAP_ERR_NOT_CHECKED) {
1125                 err_printk(ref->dev, entry,
1126                            "device driver failed to check map error"
1127                            "[device address=0x%016llx] [size=%llu bytes] "
1128                            "[mapped as %s]",
1129                            ref->dev_addr, ref->size,
1130                            type2name[entry->type]);
1131         }
1132
1133         hash_bucket_del(entry);
1134         dma_entry_free(entry);
1135
1136         put_hash_bucket(bucket, &flags);
1137 }
1138
1139 static void check_for_stack(struct device *dev,
1140                             struct page *page, size_t offset)
1141 {
1142         void *addr;
1143         struct vm_struct *stack_vm_area = task_stack_vm_area(current);
1144
1145         if (!stack_vm_area) {
1146                 /* Stack is direct-mapped. */
1147                 if (PageHighMem(page))
1148                         return;
1149                 addr = page_address(page) + offset;
1150                 if (object_is_on_stack(addr))
1151                         err_printk(dev, NULL, "device driver maps memory from stack [addr=%p]\n", addr);
1152         } else {
1153                 /* Stack is vmalloced. */
1154                 int i;
1155
1156                 for (i = 0; i < stack_vm_area->nr_pages; i++) {
1157                         if (page != stack_vm_area->pages[i])
1158                                 continue;
1159
1160                         addr = (u8 *)current->stack + i * PAGE_SIZE + offset;
1161                         err_printk(dev, NULL, "device driver maps memory from stack [probable addr=%p]\n", addr);
1162                         break;
1163                 }
1164         }
1165 }
1166
1167 static inline bool overlap(void *addr, unsigned long len, void *start, void *end)
1168 {
1169         unsigned long a1 = (unsigned long)addr;
1170         unsigned long b1 = a1 + len;
1171         unsigned long a2 = (unsigned long)start;
1172         unsigned long b2 = (unsigned long)end;
1173
1174         return !(b1 <= a2 || a1 >= b2);
1175 }
1176
1177 static void check_for_illegal_area(struct device *dev, void *addr, unsigned long len)
1178 {
1179         if (overlap(addr, len, _stext, _etext) ||
1180             overlap(addr, len, __start_rodata, __end_rodata))
1181                 err_printk(dev, NULL, "device driver maps memory from kernel text or rodata [addr=%p] [len=%lu]\n", addr, len);
1182 }
1183
1184 static void check_sync(struct device *dev,
1185                        struct dma_debug_entry *ref,
1186                        bool to_cpu)
1187 {
1188         struct dma_debug_entry *entry;
1189         struct hash_bucket *bucket;
1190         unsigned long flags;
1191
1192         bucket = get_hash_bucket(ref, &flags);
1193
1194         entry = bucket_find_contain(&bucket, ref, &flags);
1195
1196         if (!entry) {
1197                 err_printk(dev, NULL, "device driver tries "
1198                                 "to sync DMA memory it has not allocated "
1199                                 "[device address=0x%016llx] [size=%llu bytes]\n",
1200                                 (unsigned long long)ref->dev_addr, ref->size);
1201                 goto out;
1202         }
1203
1204         if (ref->size > entry->size) {
1205                 err_printk(dev, entry, "device driver syncs"
1206                                 " DMA memory outside allocated range "
1207                                 "[device address=0x%016llx] "
1208                                 "[allocation size=%llu bytes] "
1209                                 "[sync offset+size=%llu]\n",
1210                                 entry->dev_addr, entry->size,
1211                                 ref->size);
1212         }
1213
1214         if (entry->direction == DMA_BIDIRECTIONAL)
1215                 goto out;
1216
1217         if (ref->direction != entry->direction) {
1218                 err_printk(dev, entry, "device driver syncs "
1219                                 "DMA memory with different direction "
1220                                 "[device address=0x%016llx] [size=%llu bytes] "
1221                                 "[mapped with %s] [synced with %s]\n",
1222                                 (unsigned long long)ref->dev_addr, entry->size,
1223                                 dir2name[entry->direction],
1224                                 dir2name[ref->direction]);
1225         }
1226
1227         if (to_cpu && !(entry->direction == DMA_FROM_DEVICE) &&
1228                       !(ref->direction == DMA_TO_DEVICE))
1229                 err_printk(dev, entry, "device driver syncs "
1230                                 "device read-only DMA memory for cpu "
1231                                 "[device address=0x%016llx] [size=%llu bytes] "
1232                                 "[mapped with %s] [synced with %s]\n",
1233                                 (unsigned long long)ref->dev_addr, entry->size,
1234                                 dir2name[entry->direction],
1235                                 dir2name[ref->direction]);
1236
1237         if (!to_cpu && !(entry->direction == DMA_TO_DEVICE) &&
1238                        !(ref->direction == DMA_FROM_DEVICE))
1239                 err_printk(dev, entry, "device driver syncs "
1240                                 "device write-only DMA memory to device "
1241                                 "[device address=0x%016llx] [size=%llu bytes] "
1242                                 "[mapped with %s] [synced with %s]\n",
1243                                 (unsigned long long)ref->dev_addr, entry->size,
1244                                 dir2name[entry->direction],
1245                                 dir2name[ref->direction]);
1246
1247         if (ref->sg_call_ents && ref->type == dma_debug_sg &&
1248             ref->sg_call_ents != entry->sg_call_ents) {
1249                 err_printk(ref->dev, entry, "device driver syncs "
1250                            "DMA sg list with different entry count "
1251                            "[map count=%d] [sync count=%d]\n",
1252                            entry->sg_call_ents, ref->sg_call_ents);
1253         }
1254
1255 out:
1256         put_hash_bucket(bucket, &flags);
1257 }
1258
1259 static void check_sg_segment(struct device *dev, struct scatterlist *sg)
1260 {
1261 #ifdef CONFIG_DMA_API_DEBUG_SG
1262         unsigned int max_seg = dma_get_max_seg_size(dev);
1263         u64 start, end, boundary = dma_get_seg_boundary(dev);
1264
1265         /*
1266          * Either the driver forgot to set dma_parms appropriately, or
1267          * whoever generated the list forgot to check them.
1268          */
1269         if (sg->length > max_seg)
1270                 err_printk(dev, NULL, "mapping sg segment longer than device claims to support [len=%u] [max=%u]\n",
1271                            sg->length, max_seg);
1272         /*
1273          * In some cases this could potentially be the DMA API
1274          * implementation's fault, but it would usually imply that
1275          * the scatterlist was built inappropriately to begin with.
1276          */
1277         start = sg_dma_address(sg);
1278         end = start + sg_dma_len(sg) - 1;
1279         if ((start ^ end) & ~boundary)
1280                 err_printk(dev, NULL, "mapping sg segment across boundary [start=0x%016llx] [end=0x%016llx] [boundary=0x%016llx]\n",
1281                            start, end, boundary);
1282 #endif
1283 }
1284
1285 void debug_dma_map_single(struct device *dev, const void *addr,
1286                             unsigned long len)
1287 {
1288         if (unlikely(dma_debug_disabled()))
1289                 return;
1290
1291         if (!virt_addr_valid(addr))
1292                 err_printk(dev, NULL, "device driver maps memory from invalid area [addr=%p] [len=%lu]\n",
1293                            addr, len);
1294
1295         if (is_vmalloc_addr(addr))
1296                 err_printk(dev, NULL, "device driver maps memory from vmalloc area [addr=%p] [len=%lu]\n",
1297                            addr, len);
1298 }
1299 EXPORT_SYMBOL(debug_dma_map_single);
1300
1301 void debug_dma_map_page(struct device *dev, struct page *page, size_t offset,
1302                         size_t size, int direction, dma_addr_t dma_addr)
1303 {
1304         struct dma_debug_entry *entry;
1305
1306         if (unlikely(dma_debug_disabled()))
1307                 return;
1308
1309         if (dma_mapping_error(dev, dma_addr))
1310                 return;
1311
1312         entry = dma_entry_alloc();
1313         if (!entry)
1314                 return;
1315
1316         entry->dev       = dev;
1317         entry->type      = dma_debug_single;
1318         entry->pfn       = page_to_pfn(page);
1319         entry->offset    = offset,
1320         entry->dev_addr  = dma_addr;
1321         entry->size      = size;
1322         entry->direction = direction;
1323         entry->map_err_type = MAP_ERR_NOT_CHECKED;
1324
1325         check_for_stack(dev, page, offset);
1326
1327         if (!PageHighMem(page)) {
1328                 void *addr = page_address(page) + offset;
1329
1330                 check_for_illegal_area(dev, addr, size);
1331         }
1332
1333         add_dma_entry(entry);
1334 }
1335 EXPORT_SYMBOL(debug_dma_map_page);
1336
1337 void debug_dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
1338 {
1339         struct dma_debug_entry ref;
1340         struct dma_debug_entry *entry;
1341         struct hash_bucket *bucket;
1342         unsigned long flags;
1343
1344         if (unlikely(dma_debug_disabled()))
1345                 return;
1346
1347         ref.dev = dev;
1348         ref.dev_addr = dma_addr;
1349         bucket = get_hash_bucket(&ref, &flags);
1350
1351         list_for_each_entry(entry, &bucket->list, list) {
1352                 if (!exact_match(&ref, entry))
1353                         continue;
1354
1355                 /*
1356                  * The same physical address can be mapped multiple
1357                  * times. Without a hardware IOMMU this results in the
1358                  * same device addresses being put into the dma-debug
1359                  * hash multiple times too. This can result in false
1360                  * positives being reported. Therefore we implement a
1361                  * best-fit algorithm here which updates the first entry
1362                  * from the hash which fits the reference value and is
1363                  * not currently listed as being checked.
1364                  */
1365                 if (entry->map_err_type == MAP_ERR_NOT_CHECKED) {
1366                         entry->map_err_type = MAP_ERR_CHECKED;
1367                         break;
1368                 }
1369         }
1370
1371         put_hash_bucket(bucket, &flags);
1372 }
1373 EXPORT_SYMBOL(debug_dma_mapping_error);
1374
1375 void debug_dma_unmap_page(struct device *dev, dma_addr_t addr,
1376                           size_t size, int direction)
1377 {
1378         struct dma_debug_entry ref = {
1379                 .type           = dma_debug_single,
1380                 .dev            = dev,
1381                 .dev_addr       = addr,
1382                 .size           = size,
1383                 .direction      = direction,
1384         };
1385
1386         if (unlikely(dma_debug_disabled()))
1387                 return;
1388         check_unmap(&ref);
1389 }
1390 EXPORT_SYMBOL(debug_dma_unmap_page);
1391
1392 void debug_dma_map_sg(struct device *dev, struct scatterlist *sg,
1393                       int nents, int mapped_ents, int direction)
1394 {
1395         struct dma_debug_entry *entry;
1396         struct scatterlist *s;
1397         int i;
1398
1399         if (unlikely(dma_debug_disabled()))
1400                 return;
1401
1402         for_each_sg(sg, s, mapped_ents, i) {
1403                 entry = dma_entry_alloc();
1404                 if (!entry)
1405                         return;
1406
1407                 entry->type           = dma_debug_sg;
1408                 entry->dev            = dev;
1409                 entry->pfn            = page_to_pfn(sg_page(s));
1410                 entry->offset         = s->offset,
1411                 entry->size           = sg_dma_len(s);
1412                 entry->dev_addr       = sg_dma_address(s);
1413                 entry->direction      = direction;
1414                 entry->sg_call_ents   = nents;
1415                 entry->sg_mapped_ents = mapped_ents;
1416
1417                 check_for_stack(dev, sg_page(s), s->offset);
1418
1419                 if (!PageHighMem(sg_page(s))) {
1420                         check_for_illegal_area(dev, sg_virt(s), sg_dma_len(s));
1421                 }
1422
1423                 check_sg_segment(dev, s);
1424
1425                 add_dma_entry(entry);
1426         }
1427 }
1428 EXPORT_SYMBOL(debug_dma_map_sg);
1429
1430 static int get_nr_mapped_entries(struct device *dev,
1431                                  struct dma_debug_entry *ref)
1432 {
1433         struct dma_debug_entry *entry;
1434         struct hash_bucket *bucket;
1435         unsigned long flags;
1436         int mapped_ents;
1437
1438         bucket       = get_hash_bucket(ref, &flags);
1439         entry        = bucket_find_exact(bucket, ref);
1440         mapped_ents  = 0;
1441
1442         if (entry)
1443                 mapped_ents = entry->sg_mapped_ents;
1444         put_hash_bucket(bucket, &flags);
1445
1446         return mapped_ents;
1447 }
1448
1449 void debug_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
1450                         int nelems, int dir)
1451 {
1452         struct scatterlist *s;
1453         int mapped_ents = 0, i;
1454
1455         if (unlikely(dma_debug_disabled()))
1456                 return;
1457
1458         for_each_sg(sglist, s, nelems, i) {
1459
1460                 struct dma_debug_entry ref = {
1461                         .type           = dma_debug_sg,
1462                         .dev            = dev,
1463                         .pfn            = page_to_pfn(sg_page(s)),
1464                         .offset         = s->offset,
1465                         .dev_addr       = sg_dma_address(s),
1466                         .size           = sg_dma_len(s),
1467                         .direction      = dir,
1468                         .sg_call_ents   = nelems,
1469                 };
1470
1471                 if (mapped_ents && i >= mapped_ents)
1472                         break;
1473
1474                 if (!i)
1475                         mapped_ents = get_nr_mapped_entries(dev, &ref);
1476
1477                 check_unmap(&ref);
1478         }
1479 }
1480 EXPORT_SYMBOL(debug_dma_unmap_sg);
1481
1482 void debug_dma_alloc_coherent(struct device *dev, size_t size,
1483                               dma_addr_t dma_addr, void *virt)
1484 {
1485         struct dma_debug_entry *entry;
1486
1487         if (unlikely(dma_debug_disabled()))
1488                 return;
1489
1490         if (unlikely(virt == NULL))
1491                 return;
1492
1493         /* handle vmalloc and linear addresses */
1494         if (!is_vmalloc_addr(virt) && !virt_addr_valid(virt))
1495                 return;
1496
1497         entry = dma_entry_alloc();
1498         if (!entry)
1499                 return;
1500
1501         entry->type      = dma_debug_coherent;
1502         entry->dev       = dev;
1503         entry->offset    = offset_in_page(virt);
1504         entry->size      = size;
1505         entry->dev_addr  = dma_addr;
1506         entry->direction = DMA_BIDIRECTIONAL;
1507
1508         if (is_vmalloc_addr(virt))
1509                 entry->pfn = vmalloc_to_pfn(virt);
1510         else
1511                 entry->pfn = page_to_pfn(virt_to_page(virt));
1512
1513         add_dma_entry(entry);
1514 }
1515 EXPORT_SYMBOL(debug_dma_alloc_coherent);
1516
1517 void debug_dma_free_coherent(struct device *dev, size_t size,
1518                          void *virt, dma_addr_t addr)
1519 {
1520         struct dma_debug_entry ref = {
1521                 .type           = dma_debug_coherent,
1522                 .dev            = dev,
1523                 .offset         = offset_in_page(virt),
1524                 .dev_addr       = addr,
1525                 .size           = size,
1526                 .direction      = DMA_BIDIRECTIONAL,
1527         };
1528
1529         /* handle vmalloc and linear addresses */
1530         if (!is_vmalloc_addr(virt) && !virt_addr_valid(virt))
1531                 return;
1532
1533         if (is_vmalloc_addr(virt))
1534                 ref.pfn = vmalloc_to_pfn(virt);
1535         else
1536                 ref.pfn = page_to_pfn(virt_to_page(virt));
1537
1538         if (unlikely(dma_debug_disabled()))
1539                 return;
1540
1541         check_unmap(&ref);
1542 }
1543 EXPORT_SYMBOL(debug_dma_free_coherent);
1544
1545 void debug_dma_map_resource(struct device *dev, phys_addr_t addr, size_t size,
1546                             int direction, dma_addr_t dma_addr)
1547 {
1548         struct dma_debug_entry *entry;
1549
1550         if (unlikely(dma_debug_disabled()))
1551                 return;
1552
1553         entry = dma_entry_alloc();
1554         if (!entry)
1555                 return;
1556
1557         entry->type             = dma_debug_resource;
1558         entry->dev              = dev;
1559         entry->pfn              = PHYS_PFN(addr);
1560         entry->offset           = offset_in_page(addr);
1561         entry->size             = size;
1562         entry->dev_addr         = dma_addr;
1563         entry->direction        = direction;
1564         entry->map_err_type     = MAP_ERR_NOT_CHECKED;
1565
1566         add_dma_entry(entry);
1567 }
1568 EXPORT_SYMBOL(debug_dma_map_resource);
1569
1570 void debug_dma_unmap_resource(struct device *dev, dma_addr_t dma_addr,
1571                               size_t size, int direction)
1572 {
1573         struct dma_debug_entry ref = {
1574                 .type           = dma_debug_resource,
1575                 .dev            = dev,
1576                 .dev_addr       = dma_addr,
1577                 .size           = size,
1578                 .direction      = direction,
1579         };
1580
1581         if (unlikely(dma_debug_disabled()))
1582                 return;
1583
1584         check_unmap(&ref);
1585 }
1586 EXPORT_SYMBOL(debug_dma_unmap_resource);
1587
1588 void debug_dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_handle,
1589                                    size_t size, int direction)
1590 {
1591         struct dma_debug_entry ref;
1592
1593         if (unlikely(dma_debug_disabled()))
1594                 return;
1595
1596         ref.type         = dma_debug_single;
1597         ref.dev          = dev;
1598         ref.dev_addr     = dma_handle;
1599         ref.size         = size;
1600         ref.direction    = direction;
1601         ref.sg_call_ents = 0;
1602
1603         check_sync(dev, &ref, true);
1604 }
1605 EXPORT_SYMBOL(debug_dma_sync_single_for_cpu);
1606
1607 void debug_dma_sync_single_for_device(struct device *dev,
1608                                       dma_addr_t dma_handle, size_t size,
1609                                       int direction)
1610 {
1611         struct dma_debug_entry ref;
1612
1613         if (unlikely(dma_debug_disabled()))
1614                 return;
1615
1616         ref.type         = dma_debug_single;
1617         ref.dev          = dev;
1618         ref.dev_addr     = dma_handle;
1619         ref.size         = size;
1620         ref.direction    = direction;
1621         ref.sg_call_ents = 0;
1622
1623         check_sync(dev, &ref, false);
1624 }
1625 EXPORT_SYMBOL(debug_dma_sync_single_for_device);
1626
1627 void debug_dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
1628                                int nelems, int direction)
1629 {
1630         struct scatterlist *s;
1631         int mapped_ents = 0, i;
1632
1633         if (unlikely(dma_debug_disabled()))
1634                 return;
1635
1636         for_each_sg(sg, s, nelems, i) {
1637
1638                 struct dma_debug_entry ref = {
1639                         .type           = dma_debug_sg,
1640                         .dev            = dev,
1641                         .pfn            = page_to_pfn(sg_page(s)),
1642                         .offset         = s->offset,
1643                         .dev_addr       = sg_dma_address(s),
1644                         .size           = sg_dma_len(s),
1645                         .direction      = direction,
1646                         .sg_call_ents   = nelems,
1647                 };
1648
1649                 if (!i)
1650                         mapped_ents = get_nr_mapped_entries(dev, &ref);
1651
1652                 if (i >= mapped_ents)
1653                         break;
1654
1655                 check_sync(dev, &ref, true);
1656         }
1657 }
1658 EXPORT_SYMBOL(debug_dma_sync_sg_for_cpu);
1659
1660 void debug_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
1661                                   int nelems, int direction)
1662 {
1663         struct scatterlist *s;
1664         int mapped_ents = 0, i;
1665
1666         if (unlikely(dma_debug_disabled()))
1667                 return;
1668
1669         for_each_sg(sg, s, nelems, i) {
1670
1671                 struct dma_debug_entry ref = {
1672                         .type           = dma_debug_sg,
1673                         .dev            = dev,
1674                         .pfn            = page_to_pfn(sg_page(s)),
1675                         .offset         = s->offset,
1676                         .dev_addr       = sg_dma_address(s),
1677                         .size           = sg_dma_len(s),
1678                         .direction      = direction,
1679                         .sg_call_ents   = nelems,
1680                 };
1681                 if (!i)
1682                         mapped_ents = get_nr_mapped_entries(dev, &ref);
1683
1684                 if (i >= mapped_ents)
1685                         break;
1686
1687                 check_sync(dev, &ref, false);
1688         }
1689 }
1690 EXPORT_SYMBOL(debug_dma_sync_sg_for_device);
1691
1692 static int __init dma_debug_driver_setup(char *str)
1693 {
1694         int i;
1695
1696         for (i = 0; i < NAME_MAX_LEN - 1; ++i, ++str) {
1697                 current_driver_name[i] = *str;
1698                 if (*str == 0)
1699                         break;
1700         }
1701
1702         if (current_driver_name[0])
1703                 pr_info("enable driver filter for driver [%s]\n",
1704                         current_driver_name);
1705
1706
1707         return 1;
1708 }
1709 __setup("dma_debug_driver=", dma_debug_driver_setup);