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         unsigned int    stack_len;
  93         unsigned long   stack_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 /* per-driver filter related state */
 138
 139 #define NAME_MAX_LEN    64
 140
 141 static char                  current_driver_name[NAME_MAX_LEN] __read_mostly;
 142 static struct device_driver *current_driver                    __read_mostly;
 143
 144 static DEFINE_RWLOCK(driver_name_lock);
 145
 146 static const char *const maperr2str[] = {
 147         [MAP_ERR_CHECK_NOT_APPLICABLE] = "dma map error check not applicable",
 148         [MAP_ERR_NOT_CHECKED] = "dma map error not checked",
 149         [MAP_ERR_CHECKED] = "dma map error checked",
 150 };
 151
 152 static const char *type2name[5] = { "single", "page",
 153                                     "scather-gather", "coherent",
 154                                     "resource" };
 155
 156 static const char *dir2name[4] = { "DMA_BIDIRECTIONAL", "DMA_TO_DEVICE",
 157                                    "DMA_FROM_DEVICE", "DMA_NONE" };
 158
 159 /*
 160  * The access to some variables in this macro is racy. We can't use atomic_t
 161  * here because all these variables are exported to debugfs. Some of them even
 162  * writeable. This is also the reason why a lock won't help much. But anyway,
 163  * the races are no big deal. Here is why:
 164  *
 165  *   error_count: the addition is racy, but the worst thing that can happen is
 166  *                that we don't count some errors
 167  *   show_num_errors: the subtraction is racy. Also no big deal because in
 168  *                    worst case this will result in one warning more in the
 169  *                    system log than the user configured. This variable is
 170  *                    writeable via debugfs.
 171  */
 172 static inline void dump_entry_trace(struct dma_debug_entry *entry)
 173 {
 174 #ifdef CONFIG_STACKTRACE
 175         if (entry) {
 176                 pr_warning("Mapped at:\n");
 177                 stack_trace_print(entry->stack_entries, entry->stack_len, 0);
 178         }
 179 #endif
 180 }
 181
 182 static bool driver_filter(struct device *dev)
 183 {
 184         struct device_driver *drv;
 185         unsigned long flags;
 186         bool ret;
 187
 188         /* driver filter off */
 189         if (likely(!current_driver_name[0]))
 190                 return true;
 191
 192         /* driver filter on and initialized */
 193         if (current_driver && dev && dev->driver == current_driver)
 194                 return true;
 195
 196         /* driver filter on, but we can't filter on a NULL device... */
 197         if (!dev)
 198                 return false;
 199
 200         if (current_driver || !current_driver_name[0])
 201                 return false;
 202
 203         /* driver filter on but not yet initialized */
 204         drv = dev->driver;
 205         if (!drv)
 206                 return false;
 207
 208         /* lock to protect against change of current_driver_name */
 209         read_lock_irqsave(&driver_name_lock, flags);
 210
 211         ret = false;
 212         if (drv->name &&
 213             strncmp(current_driver_name, drv->name, NAME_MAX_LEN - 1) == 0) {
 214                 current_driver = drv;
 215                 ret = true;
 216         }
 217
 218         read_unlock_irqrestore(&driver_name_lock, flags);
 219
 220         return ret;
 221 }
 222
 223 #define err_printk(dev, entry, format, arg...) do {                     \
 224                 error_count += 1;                                       \
 225                 if (driver_filter(dev) &&                               \
 226                     (show_all_errors || show_num_errors > 0)) {         \
 227                         WARN(1, pr_fmt("%s %s: ") format,               \
 228                              dev ? dev_driver_string(dev) : "NULL",     \
 229                              dev ? dev_name(dev) : "NULL", ## arg);     \
 230                         dump_entry_trace(entry);                        \
 231                 }                                                       \
 232                 if (!show_all_errors && show_num_errors > 0)            \
 233                         show_num_errors -= 1;                           \
 234         } while (0);
 235
 236 /*
 237  * Hash related functions
 238  *
 239  * Every DMA-API request is saved into a struct dma_debug_entry. To
 240  * have quick access to these structs they are stored into a hash.
 241  */
 242 static int hash_fn(struct dma_debug_entry *entry)
 243 {
 244         /*
 245          * Hash function is based on the dma address.
 246          * We use bits 20-27 here as the index into the hash
 247          */
 248         return (entry->dev_addr >> HASH_FN_SHIFT) & HASH_FN_MASK;
 249 }
 250
 251 /*
 252  * Request exclusive access to a hash bucket for a given dma_debug_entry.
 253  */
 254 static struct hash_bucket *get_hash_bucket(struct dma_debug_entry *entry,
 255                                            unsigned long *flags)
 256         __acquires(&dma_entry_hash[idx].lock)
 257 {
 258         int idx = hash_fn(entry);
 259         unsigned long __flags;
 260
 261         spin_lock_irqsave(&dma_entry_hash[idx].lock, __flags);
 262         *flags = __flags;
 263         return &dma_entry_hash[idx];
 264 }
 265
 266 /*
 267  * Give up exclusive access to the hash bucket
 268  */
 269 static void put_hash_bucket(struct hash_bucket *bucket,
 270                             unsigned long *flags)
 271         __releases(&bucket->lock)
 272 {
 273         unsigned long __flags = *flags;
 274
 275         spin_unlock_irqrestore(&bucket->lock, __flags);
 276 }
 277
 278 static bool exact_match(struct dma_debug_entry *a, struct dma_debug_entry *b)
 279 {
 280         return ((a->dev_addr == b->dev_addr) &&
 281                 (a->dev == b->dev)) ? true : false;
 282 }
 283
 284 static bool containing_match(struct dma_debug_entry *a,
 285                              struct dma_debug_entry *b)
 286 {
 287         if (a->dev != b->dev)
 288                 return false;
 289
 290         if ((b->dev_addr <= a->dev_addr) &&
 291             ((b->dev_addr + b->size) >= (a->dev_addr + a->size)))
 292                 return true;
 293
 294         return false;
 295 }
 296
 297 /*
 298  * Search a given entry in the hash bucket list
 299  */
 300 static struct dma_debug_entry *__hash_bucket_find(struct hash_bucket *bucket,
 301                                                   struct dma_debug_entry *ref,
 302                                                   match_fn match)
 303 {
 304         struct dma_debug_entry *entry, *ret = NULL;
 305         int matches = 0, match_lvl, last_lvl = -1;
 306
 307         list_for_each_entry(entry, &bucket->list, list) {
 308                 if (!match(ref, entry))
 309                         continue;
 310
 311                 /*
 312                  * Some drivers map the same physical address multiple
 313                  * times. Without a hardware IOMMU this results in the
 314                  * same device addresses being put into the dma-debug
 315                  * hash multiple times too. This can result in false
 316                  * positives being reported. Therefore we implement a
 317                  * best-fit algorithm here which returns the entry from
 318                  * the hash which fits best to the reference value
 319                  * instead of the first-fit.
 320                  */
 321                 matches += 1;
 322                 match_lvl = 0;
 323                 entry->size         == ref->size         ? ++match_lvl : 0;
 324                 entry->type         == ref->type         ? ++match_lvl : 0;
 325                 entry->direction    == ref->direction    ? ++match_lvl : 0;
 326                 entry->sg_call_ents == ref->sg_call_ents ? ++match_lvl : 0;
 327
 328                 if (match_lvl == 4) {
 329                         /* perfect-fit - return the result */
 330                         return entry;
 331                 } else if (match_lvl > last_lvl) {
 332                         /*
 333                          * We found an entry that fits better then the
 334                          * previous one or it is the 1st match.
 335                          */
 336                         last_lvl = match_lvl;
 337                         ret      = entry;
 338                 }
 339         }
 340
 341         /*
 342          * If we have multiple matches but no perfect-fit, just return
 343          * NULL.
 344          */
 345         ret = (matches == 1) ? ret : NULL;
 346
 347         return ret;
 348 }
 349
 350 static struct dma_debug_entry *bucket_find_exact(struct hash_bucket *bucket,
 351                                                  struct dma_debug_entry *ref)
 352 {
 353         return __hash_bucket_find(bucket, ref, exact_match);
 354 }
 355
 356 static struct dma_debug_entry *bucket_find_contain(struct hash_bucket **bucket,
 357                                                    struct dma_debug_entry *ref,
 358                                                    unsigned long *flags)
 359 {
 360
 361         unsigned int max_range = dma_get_max_seg_size(ref->dev);
 362         struct dma_debug_entry *entry, index = *ref;
 363         unsigned int range = 0;
 364
 365         while (range <= max_range) {
 366                 entry = __hash_bucket_find(*bucket, ref, containing_match);
 367
 368                 if (entry)
 369                         return entry;
 370
 371                 /*
 372                  * Nothing found, go back a hash bucket
 373                  */
 374                 put_hash_bucket(*bucket, flags);
 375                 range          += (1 << HASH_FN_SHIFT);
 376                 index.dev_addr -= (1 << HASH_FN_SHIFT);
 377                 *bucket = get_hash_bucket(&index, flags);
 378         }
 379
 380         return NULL;
 381 }
 382
 383 /*
 384  * Add an entry to a hash bucket
 385  */
 386 static void hash_bucket_add(struct hash_bucket *bucket,
 387                             struct dma_debug_entry *entry)
 388 {
 389         list_add_tail(&entry->list, &bucket->list);
 390 }
 391
 392 /*
 393  * Remove entry from a hash bucket list
 394  */
 395 static void hash_bucket_del(struct dma_debug_entry *entry)
 396 {
 397         list_del(&entry->list);
 398 }
 399
 400 static unsigned long long phys_addr(struct dma_debug_entry *entry)
 401 {
 402         if (entry->type == dma_debug_resource)
 403                 return __pfn_to_phys(entry->pfn) + entry->offset;
 404
 405         return page_to_phys(pfn_to_page(entry->pfn)) + entry->offset;
 406 }
 407
 408 /*
 409  * Dump mapping entries for debugging purposes
 410  */
 411 void debug_dma_dump_mappings(struct device *dev)
 412 {
 413         int idx;
 414
 415         for (idx = 0; idx < HASH_SIZE; idx++) {
 416                 struct hash_bucket *bucket = &dma_entry_hash[idx];
 417                 struct dma_debug_entry *entry;
 418                 unsigned long flags;
 419
 420                 spin_lock_irqsave(&bucket->lock, flags);
 421
 422                 list_for_each_entry(entry, &bucket->list, list) {
 423                         if (!dev || dev == entry->dev) {
 424                                 dev_info(entry->dev,
 425                                          "%s idx %d P=%Lx N=%lx D=%Lx L=%Lx %s %s\n",
 426                                          type2name[entry->type], idx,
 427                                          phys_addr(entry), entry->pfn,
 428                                          entry->dev_addr, entry->size,
 429                                          dir2name[entry->direction],
 430                                          maperr2str[entry->map_err_type]);
 431                         }
 432                 }
 433
 434                 spin_unlock_irqrestore(&bucket->lock, flags);
 435         }
 436 }
 437
 438 /*
 439  * For each mapping (initial cacheline in the case of
 440  * dma_alloc_coherent/dma_map_page, initial cacheline in each page of a
 441  * scatterlist, or the cacheline specified in dma_map_single) insert
 442  * into this tree using the cacheline as the key. At
 443  * dma_unmap_{single|sg|page} or dma_free_coherent delete the entry.  If
 444  * the entry already exists at insertion time add a tag as a reference
 445  * count for the overlapping mappings.  For now, the overlap tracking
 446  * just ensures that 'unmaps' balance 'maps' before marking the
 447  * cacheline idle, but we should also be flagging overlaps as an API
 448  * violation.
 449  *
 450  * Memory usage is mostly constrained by the maximum number of available
 451  * dma-debug entries in that we need a free dma_debug_entry before
 452  * inserting into the tree.  In the case of dma_map_page and
 453  * dma_alloc_coherent there is only one dma_debug_entry and one
 454  * dma_active_cacheline entry to track per event.  dma_map_sg(), on the
 455  * other hand, consumes a single dma_debug_entry, but inserts 'nents'
 456  * entries into the tree.
 457  *
 458  * At any time debug_dma_assert_idle() can be called to trigger a
 459  * warning if any cachelines in the given page are in the active set.
 460  */
 461 static RADIX_TREE(dma_active_cacheline, GFP_NOWAIT);
 462 static DEFINE_SPINLOCK(radix_lock);
 463 #define ACTIVE_CACHELINE_MAX_OVERLAP ((1 << RADIX_TREE_MAX_TAGS) - 1)
 464 #define CACHELINE_PER_PAGE_SHIFT (PAGE_SHIFT - L1_CACHE_SHIFT)
 465 #define CACHELINES_PER_PAGE (1 << CACHELINE_PER_PAGE_SHIFT)
 466
 467 static phys_addr_t to_cacheline_number(struct dma_debug_entry *entry)
 468 {
 469         return (entry->pfn << CACHELINE_PER_PAGE_SHIFT) +
 470                 (entry->offset >> L1_CACHE_SHIFT);
 471 }
 472
 473 static int active_cacheline_read_overlap(phys_addr_t cln)
 474 {
 475         int overlap = 0, i;
 476
 477         for (i = RADIX_TREE_MAX_TAGS - 1; i >= 0; i--)
 478                 if (radix_tree_tag_get(&dma_active_cacheline, cln, i))
 479                         overlap |= 1 << i;
 480         return overlap;
 481 }
 482
 483 static int active_cacheline_set_overlap(phys_addr_t cln, int overlap)
 484 {
 485         int i;
 486
 487         if (overlap > ACTIVE_CACHELINE_MAX_OVERLAP || overlap < 0)
 488                 return overlap;
 489
 490         for (i = RADIX_TREE_MAX_TAGS - 1; i >= 0; i--)
 491                 if (overlap & 1 << i)
 492                         radix_tree_tag_set(&dma_active_cacheline, cln, i);
 493                 else
 494                         radix_tree_tag_clear(&dma_active_cacheline, cln, i);
 495
 496         return overlap;
 497 }
 498
 499 static void active_cacheline_inc_overlap(phys_addr_t cln)
 500 {
 501         int overlap = active_cacheline_read_overlap(cln);
 502
 503         overlap = active_cacheline_set_overlap(cln, ++overlap);
 504
 505         /* If we overflowed the overlap counter then we're potentially
 506          * leaking dma-mappings.  Otherwise, if maps and unmaps are
 507          * balanced then this overflow may cause false negatives in
 508          * debug_dma_assert_idle() as the cacheline may be marked idle
 509          * prematurely.
 510          */
 511         WARN_ONCE(overlap > ACTIVE_CACHELINE_MAX_OVERLAP,
 512                   pr_fmt("exceeded %d overlapping mappings of cacheline %pa\n"),
 513                   ACTIVE_CACHELINE_MAX_OVERLAP, &cln);
 514 }
 515
 516 static int active_cacheline_dec_overlap(phys_addr_t cln)
 517 {
 518         int overlap = active_cacheline_read_overlap(cln);
 519
 520         return active_cacheline_set_overlap(cln, --overlap);
 521 }
 522
 523 static int active_cacheline_insert(struct dma_debug_entry *entry)
 524 {
 525         phys_addr_t cln = to_cacheline_number(entry);
 526         unsigned long flags;
 527         int rc;
 528
 529         /* If the device is not writing memory then we don't have any
 530          * concerns about the cpu consuming stale data.  This mitigates
 531          * legitimate usages of overlapping mappings.
 532          */
 533         if (entry->direction == DMA_TO_DEVICE)
 534                 return 0;
 535
 536         spin_lock_irqsave(&radix_lock, flags);
 537         rc = radix_tree_insert(&dma_active_cacheline, cln, entry);
 538         if (rc == -EEXIST)
 539                 active_cacheline_inc_overlap(cln);
 540         spin_unlock_irqrestore(&radix_lock, flags);
 541
 542         return rc;
 543 }
 544
 545 static void active_cacheline_remove(struct dma_debug_entry *entry)
 546 {
 547         phys_addr_t cln = to_cacheline_number(entry);
 548         unsigned long flags;
 549
 550         /* ...mirror the insert case */
 551         if (entry->direction == DMA_TO_DEVICE)
 552                 return;
 553
 554         spin_lock_irqsave(&radix_lock, flags);
 555         /* since we are counting overlaps the final put of the
 556          * cacheline will occur when the overlap count is 0.
 557          * active_cacheline_dec_overlap() returns -1 in that case
 558          */
 559         if (active_cacheline_dec_overlap(cln) < 0)
 560                 radix_tree_delete(&dma_active_cacheline, cln);
 561         spin_unlock_irqrestore(&radix_lock, flags);
 562 }
 563
 564 /**
 565  * debug_dma_assert_idle() - assert that a page is not undergoing dma
 566  * @page: page to lookup in the dma_active_cacheline tree
 567  *
 568  * Place a call to this routine in cases where the cpu touching the page
 569  * before the dma completes (page is dma_unmapped) will lead to data
 570  * corruption.
 571  */
 572 void debug_dma_assert_idle(struct page *page)
 573 {
 574         static struct dma_debug_entry *ents[CACHELINES_PER_PAGE];
 575         struct dma_debug_entry *entry = NULL;
 576         void **results = (void **) &ents;
 577         unsigned int nents, i;
 578         unsigned long flags;
 579         phys_addr_t cln;
 580
 581         if (dma_debug_disabled())
 582                 return;
 583
 584         if (!page)
 585                 return;
 586
 587         cln = (phys_addr_t) page_to_pfn(page) << CACHELINE_PER_PAGE_SHIFT;
 588         spin_lock_irqsave(&radix_lock, flags);
 589         nents = radix_tree_gang_lookup(&dma_active_cacheline, results, cln,
 590                                        CACHELINES_PER_PAGE);
 591         for (i = 0; i < nents; i++) {
 592                 phys_addr_t ent_cln = to_cacheline_number(ents[i]);
 593
 594                 if (ent_cln == cln) {
 595                         entry = ents[i];
 596                         break;
 597                 } else if (ent_cln >= cln + CACHELINES_PER_PAGE)
 598                         break;
 599         }
 600         spin_unlock_irqrestore(&radix_lock, flags);
 601
 602         if (!entry)
 603                 return;
 604
 605         cln = to_cacheline_number(entry);
 606         err_printk(entry->dev, entry,
 607                    "cpu touching an active dma mapped cacheline [cln=%pa]\n",
 608                    &cln);
 609 }
 610
 611 /*
 612  * Wrapper function for adding an entry to the hash.
 613  * This function takes care of locking itself.
 614  */
 615 static void add_dma_entry(struct dma_debug_entry *entry)
 616 {
 617         struct hash_bucket *bucket;
 618         unsigned long flags;
 619         int rc;
 620
 621         bucket = get_hash_bucket(entry, &flags);
 622         hash_bucket_add(bucket, entry);
 623         put_hash_bucket(bucket, &flags);
 624
 625         rc = active_cacheline_insert(entry);
 626         if (rc == -ENOMEM) {
 627                 pr_err("cacheline tracking ENOMEM, dma-debug disabled\n");
 628                 global_disable = true;
 629         }
 630
 631         /* TODO: report -EEXIST errors here as overlapping mappings are
 632          * not supported by the DMA API
 633          */
 634 }
 635
 636 static int dma_debug_create_entries(gfp_t gfp)
 637 {
 638         struct dma_debug_entry *entry;
 639         int i;
 640
 641         entry = (void *)get_zeroed_page(gfp);
 642         if (!entry)
 643                 return -ENOMEM;
 644
 645         for (i = 0; i < DMA_DEBUG_DYNAMIC_ENTRIES; i++)
 646                 list_add_tail(&entry[i].list, &free_entries);
 647
 648         num_free_entries += DMA_DEBUG_DYNAMIC_ENTRIES;
 649         nr_total_entries += DMA_DEBUG_DYNAMIC_ENTRIES;
 650
 651         return 0;
 652 }
 653
 654 static struct dma_debug_entry *__dma_entry_alloc(void)
 655 {
 656         struct dma_debug_entry *entry;
 657
 658         entry = list_entry(free_entries.next, struct dma_debug_entry, list);
 659         list_del(&entry->list);
 660         memset(entry, 0, sizeof(*entry));
 661
 662         num_free_entries -= 1;
 663         if (num_free_entries < min_free_entries)
 664                 min_free_entries = num_free_entries;
 665
 666         return entry;
 667 }
 668
 669 void __dma_entry_alloc_check_leak(void)
 670 {
 671         u32 tmp = nr_total_entries % nr_prealloc_entries;
 672
 673         /* Shout each time we tick over some multiple of the initial pool */
 674         if (tmp < DMA_DEBUG_DYNAMIC_ENTRIES) {
 675                 pr_info("dma_debug_entry pool grown to %u (%u00%%)\n",
 676                         nr_total_entries,
 677                         (nr_total_entries / nr_prealloc_entries));
 678         }
 679 }
 680
 681 /* struct dma_entry allocator
 682  *
 683  * The next two functions implement the allocator for
 684  * struct dma_debug_entries.
 685  */
 686 static struct dma_debug_entry *dma_entry_alloc(void)
 687 {
 688         struct dma_debug_entry *entry;
 689         unsigned long flags;
 690
 691         spin_lock_irqsave(&free_entries_lock, flags);
 692         if (num_free_entries == 0) {
 693                 if (dma_debug_create_entries(GFP_ATOMIC)) {
 694                         global_disable = true;
 695                         spin_unlock_irqrestore(&free_entries_lock, flags);
 696                         pr_err("debugging out of memory - disabling\n");
 697                         return NULL;
 698                 }
 699                 __dma_entry_alloc_check_leak();
 700         }
 701
 702         entry = __dma_entry_alloc();
 703
 704         spin_unlock_irqrestore(&free_entries_lock, flags);
 705
 706 #ifdef CONFIG_STACKTRACE
 707         entry->stack_len = stack_trace_save(entry->stack_entries,
 708                                             ARRAY_SIZE(entry->stack_entries),
 709                                             1);
 710 #endif
 711         return entry;
 712 }
 713
 714 static void dma_entry_free(struct dma_debug_entry *entry)
 715 {
 716         unsigned long flags;
 717
 718         active_cacheline_remove(entry);
 719
 720         /*
 721          * add to beginning of the list - this way the entries are
 722          * more likely cache hot when they are reallocated.
 723          */
 724         spin_lock_irqsave(&free_entries_lock, flags);
 725         list_add(&entry->list, &free_entries);
 726         num_free_entries += 1;
 727         spin_unlock_irqrestore(&free_entries_lock, flags);
 728 }
 729
 730 /*
 731  * DMA-API debugging init code
 732  *
 733  * The init code does two things:
 734  *   1. Initialize core data structures
 735  *   2. Preallocate a given number of dma_debug_entry structs
 736  */
 737
 738 static ssize_t filter_read(struct file *file, char __user *user_buf,
 739                            size_t count, loff_t *ppos)
 740 {
 741         char buf[NAME_MAX_LEN + 1];
 742         unsigned long flags;
 743         int len;
 744
 745         if (!current_driver_name[0])
 746                 return 0;
 747
 748         /*
 749          * We can't copy to userspace directly because current_driver_name can
 750          * only be read under the driver_name_lock with irqs disabled. So
 751          * create a temporary copy first.
 752          */
 753         read_lock_irqsave(&driver_name_lock, flags);
 754         len = scnprintf(buf, NAME_MAX_LEN + 1, "%s\n", current_driver_name);
 755         read_unlock_irqrestore(&driver_name_lock, flags);
 756
 757         return simple_read_from_buffer(user_buf, count, ppos, buf, len);
 758 }
 759
 760 static ssize_t filter_write(struct file *file, const char __user *userbuf,
 761                             size_t count, loff_t *ppos)
 762 {
 763         char buf[NAME_MAX_LEN];
 764         unsigned long flags;
 765         size_t len;
 766         int i;
 767
 768         /*
 769          * We can't copy from userspace directly. Access to
 770          * current_driver_name is protected with a write_lock with irqs
 771          * disabled. Since copy_from_user can fault and may sleep we
 772          * need to copy to temporary buffer first
 773          */
 774         len = min(count, (size_t)(NAME_MAX_LEN - 1));
 775         if (copy_from_user(buf, userbuf, len))
 776                 return -EFAULT;
 777
 778         buf[len] = 0;
 779
 780         write_lock_irqsave(&driver_name_lock, flags);
 781
 782         /*
 783          * Now handle the string we got from userspace very carefully.
 784          * The rules are:
 785          *         - only use the first token we got
 786          *         - token delimiter is everything looking like a space
 787          *           character (' ', '\n', '\t' ...)
 788          *
 789          */
 790         if (!isalnum(buf[0])) {
 791                 /*
 792                  * If the first character userspace gave us is not
 793                  * alphanumerical then assume the filter should be
 794                  * switched off.
 795                  */
 796                 if (current_driver_name[0])
 797                         pr_info("switching off dma-debug driver filter\n");
 798                 current_driver_name[0] = 0;
 799                 current_driver = NULL;
 800                 goto out_unlock;
 801         }
 802
 803         /*
 804          * Now parse out the first token and use it as the name for the
 805          * driver to filter for.
 806          */
 807         for (i = 0; i < NAME_MAX_LEN - 1; ++i) {
 808                 current_driver_name[i] = buf[i];
 809                 if (isspace(buf[i]) || buf[i] == ' ' || buf[i] == 0)
 810                         break;
 811         }
 812         current_driver_name[i] = 0;
 813         current_driver = NULL;
 814
 815         pr_info("enable driver filter for driver [%s]\n",
 816                 current_driver_name);
 817
 818 out_unlock:
 819         write_unlock_irqrestore(&driver_name_lock, flags);
 820
 821         return count;
 822 }
 823
 824 static const struct file_operations filter_fops = {
 825         .read  = filter_read,
 826         .write = filter_write,
 827         .llseek = default_llseek,
 828 };
 829
 830 static int dump_show(struct seq_file *seq, void *v)
 831 {
 832         int idx;
 833
 834         for (idx = 0; idx < HASH_SIZE; idx++) {
 835                 struct hash_bucket *bucket = &dma_entry_hash[idx];
 836                 struct dma_debug_entry *entry;
 837                 unsigned long flags;
 838
 839                 spin_lock_irqsave(&bucket->lock, flags);
 840                 list_for_each_entry(entry, &bucket->list, list) {
 841                         seq_printf(seq,
 842                                    "%s %s %s idx %d P=%llx N=%lx D=%llx L=%llx %s %s\n",
 843                                    dev_name(entry->dev),
 844                                    dev_driver_string(entry->dev),
 845                                    type2name[entry->type], idx,
 846                                    phys_addr(entry), entry->pfn,
 847                                    entry->dev_addr, entry->size,
 848                                    dir2name[entry->direction],
 849                                    maperr2str[entry->map_err_type]);
 850                 }
 851                 spin_unlock_irqrestore(&bucket->lock, flags);
 852         }
 853         return 0;
 854 }
 855 DEFINE_SHOW_ATTRIBUTE(dump);
 856
 857 static void dma_debug_fs_init(void)
 858 {
 859         struct dentry *dentry = debugfs_create_dir("dma-api", NULL);
 860
 861         debugfs_create_bool("disabled", 0444, dentry, &global_disable);
 862         debugfs_create_u32("error_count", 0444, dentry, &error_count);
 863         debugfs_create_u32("all_errors", 0644, dentry, &show_all_errors);
 864         debugfs_create_u32("num_errors", 0644, dentry, &show_num_errors);
 865         debugfs_create_u32("num_free_entries", 0444, dentry, &num_free_entries);
 866         debugfs_create_u32("min_free_entries", 0444, dentry, &min_free_entries);
 867         debugfs_create_u32("nr_total_entries", 0444, dentry, &nr_total_entries);
 868         debugfs_create_file("driver_filter", 0644, dentry, NULL, &filter_fops);
 869         debugfs_create_file("dump", 0444, dentry, NULL, &dump_fops);
 870 }
 871
 872 static int device_dma_allocations(struct device *dev, struct dma_debug_entry **out_entry)
 873 {
 874         struct dma_debug_entry *entry;
 875         unsigned long flags;
 876         int count = 0, i;
 877
 878         for (i = 0; i < HASH_SIZE; ++i) {
 879                 spin_lock_irqsave(&dma_entry_hash[i].lock, flags);
 880                 list_for_each_entry(entry, &dma_entry_hash[i].list, list) {
 881                         if (entry->dev == dev) {
 882                                 count += 1;
 883                                 *out_entry = entry;
 884                         }
 885                 }
 886                 spin_unlock_irqrestore(&dma_entry_hash[i].lock, flags);
 887         }
 888
 889         return count;
 890 }
 891
 892 static int dma_debug_device_change(struct notifier_block *nb, unsigned long action, void *data)
 893 {
 894         struct device *dev = data;
 895         struct dma_debug_entry *uninitialized_var(entry);
 896         int count;
 897
 898         if (dma_debug_disabled())
 899                 return 0;
 900
 901         switch (action) {
 902         case BUS_NOTIFY_UNBOUND_DRIVER:
 903                 count = device_dma_allocations(dev, &entry);
 904                 if (count == 0)
 905                         break;
 906                 err_printk(dev, entry, "device driver has pending "
 907                                 "DMA allocations while released from device "
 908                                 "[count=%d]\n"
 909                                 "One of leaked entries details: "
 910                                 "[device address=0x%016llx] [size=%llu bytes] "
 911                                 "[mapped with %s] [mapped as %s]\n",
 912                         count, entry->dev_addr, entry->size,
 913                         dir2name[entry->direction], type2name[entry->type]);
 914                 break;
 915         default:
 916                 break;
 917         }
 918
 919         return 0;
 920 }
 921
 922 void dma_debug_add_bus(struct bus_type *bus)
 923 {
 924         struct notifier_block *nb;
 925
 926         if (dma_debug_disabled())
 927                 return;
 928
 929         nb = kzalloc(sizeof(struct notifier_block), GFP_KERNEL);
 930         if (nb == NULL) {
 931                 pr_err("dma_debug_add_bus: out of memory\n");
 932                 return;
 933         }
 934
 935         nb->notifier_call = dma_debug_device_change;
 936
 937         bus_register_notifier(bus, nb);
 938 }
 939
 940 static int dma_debug_init(void)
 941 {
 942         int i, nr_pages;
 943
 944         /* Do not use dma_debug_initialized here, since we really want to be
 945          * called to set dma_debug_initialized
 946          */
 947         if (global_disable)
 948                 return 0;
 949
 950         for (i = 0; i < HASH_SIZE; ++i) {
 951                 INIT_LIST_HEAD(&dma_entry_hash[i].list);
 952                 spin_lock_init(&dma_entry_hash[i].lock);
 953         }
 954
 955         dma_debug_fs_init();
 956
 957         nr_pages = DIV_ROUND_UP(nr_prealloc_entries, DMA_DEBUG_DYNAMIC_ENTRIES);
 958         for (i = 0; i < nr_pages; ++i)
 959                 dma_debug_create_entries(GFP_KERNEL);
 960         if (num_free_entries >= nr_prealloc_entries) {
 961                 pr_info("preallocated %d debug entries\n", nr_total_entries);
 962         } else if (num_free_entries > 0) {
 963                 pr_warn("%d debug entries requested but only %d allocated\n",
 964                         nr_prealloc_entries, nr_total_entries);
 965         } else {
 966                 pr_err("debugging out of memory error - disabled\n");
 967                 global_disable = true;
 968
 969                 return 0;
 970         }
 971         min_free_entries = num_free_entries;
 972
 973         dma_debug_initialized = true;
 974
 975         pr_info("debugging enabled by kernel config\n");
 976         return 0;
 977 }
 978 core_initcall(dma_debug_init);
 979
 980 static __init int dma_debug_cmdline(char *str)
 981 {
 982         if (!str)
 983                 return -EINVAL;
 984
 985         if (strncmp(str, "off", 3) == 0) {
 986                 pr_info("debugging disabled on kernel command line\n");
 987                 global_disable = true;
 988         }
 989
 990         return 0;
 991 }
 992
 993 static __init int dma_debug_entries_cmdline(char *str)
 994 {
 995         if (!str)
 996                 return -EINVAL;
 997         if (!get_option(&str, &nr_prealloc_entries))
 998                 nr_prealloc_entries = PREALLOC_DMA_DEBUG_ENTRIES;
 999         return 0;
1000 }
1001
1002 __setup("dma_debug=", dma_debug_cmdline);
1003 __setup("dma_debug_entries=", dma_debug_entries_cmdline);
1004
1005 static void check_unmap(struct dma_debug_entry *ref)
1006 {
1007         struct dma_debug_entry *entry;
1008         struct hash_bucket *bucket;
1009         unsigned long flags;
1010
1011         bucket = get_hash_bucket(ref, &flags);
1012         entry = bucket_find_exact(bucket, ref);
1013
1014         if (!entry) {
1015                 /* must drop lock before calling dma_mapping_error */
1016                 put_hash_bucket(bucket, &flags);
1017
1018                 if (dma_mapping_error(ref->dev, ref->dev_addr)) {
1019                         err_printk(ref->dev, NULL,
1020                                    "device driver tries to free an "
1021                                    "invalid DMA memory address\n");
1022                 } else {
1023                         err_printk(ref->dev, NULL,
1024                                    "device driver tries to free DMA "
1025                                    "memory it has not allocated [device "
1026                                    "address=0x%016llx] [size=%llu bytes]\n",
1027                                    ref->dev_addr, ref->size);
1028                 }
1029                 return;
1030         }
1031
1032         if (ref->size != entry->size) {
1033                 err_printk(ref->dev, entry, "device driver frees "
1034                            "DMA memory with different size "
1035                            "[device address=0x%016llx] [map size=%llu bytes] "
1036                            "[unmap size=%llu bytes]\n",
1037                            ref->dev_addr, entry->size, ref->size);
1038         }
1039
1040         if (ref->type != entry->type) {
1041                 err_printk(ref->dev, entry, "device driver frees "
1042                            "DMA memory with wrong function "
1043                            "[device address=0x%016llx] [size=%llu bytes] "
1044                            "[mapped as %s] [unmapped as %s]\n",
1045                            ref->dev_addr, ref->size,
1046                            type2name[entry->type], type2name[ref->type]);
1047         } else if ((entry->type == dma_debug_coherent) &&
1048                    (phys_addr(ref) != phys_addr(entry))) {
1049                 err_printk(ref->dev, entry, "device driver frees "
1050                            "DMA memory with different CPU address "
1051                            "[device address=0x%016llx] [size=%llu bytes] "
1052                            "[cpu alloc address=0x%016llx] "
1053                            "[cpu free address=0x%016llx]",
1054                            ref->dev_addr, ref->size,
1055                            phys_addr(entry),
1056                            phys_addr(ref));
1057         }
1058
1059         if (ref->sg_call_ents && ref->type == dma_debug_sg &&
1060             ref->sg_call_ents != entry->sg_call_ents) {
1061                 err_printk(ref->dev, entry, "device driver frees "
1062                            "DMA sg list with different entry count "
1063                            "[map count=%d] [unmap count=%d]\n",
1064                            entry->sg_call_ents, ref->sg_call_ents);
1065         }
1066
1067         /*
1068          * This may be no bug in reality - but most implementations of the
1069          * DMA API don't handle this properly, so check for it here
1070          */
1071         if (ref->direction != entry->direction) {
1072                 err_printk(ref->dev, entry, "device driver frees "
1073                            "DMA memory with different direction "
1074                            "[device address=0x%016llx] [size=%llu bytes] "
1075                            "[mapped with %s] [unmapped with %s]\n",
1076                            ref->dev_addr, ref->size,
1077                            dir2name[entry->direction],
1078                            dir2name[ref->direction]);
1079         }
1080
1081         /*
1082          * Drivers should use dma_mapping_error() to check the returned
1083          * addresses of dma_map_single() and dma_map_page().
1084          * If not, print this warning message. See Documentation/DMA-API.txt.
1085          */
1086         if (entry->map_err_type == MAP_ERR_NOT_CHECKED) {
1087                 err_printk(ref->dev, entry,
1088                            "device driver failed to check map error"
1089                            "[device address=0x%016llx] [size=%llu bytes] "
1090                            "[mapped as %s]",
1091                            ref->dev_addr, ref->size,
1092                            type2name[entry->type]);
1093         }
1094
1095         hash_bucket_del(entry);
1096         dma_entry_free(entry);
1097
1098         put_hash_bucket(bucket, &flags);
1099 }
1100
1101 static void check_for_stack(struct device *dev,
1102                             struct page *page, size_t offset)
1103 {
1104         void *addr;
1105         struct vm_struct *stack_vm_area = task_stack_vm_area(current);
1106
1107         if (!stack_vm_area) {
1108                 /* Stack is direct-mapped. */
1109                 if (PageHighMem(page))
1110                         return;
1111                 addr = page_address(page) + offset;
1112                 if (object_is_on_stack(addr))
1113                         err_printk(dev, NULL, "device driver maps memory from stack [addr=%p]\n", addr);
1114         } else {
1115                 /* Stack is vmalloced. */
1116                 int i;
1117
1118                 for (i = 0; i < stack_vm_area->nr_pages; i++) {
1119                         if (page != stack_vm_area->pages[i])
1120                                 continue;
1121
1122                         addr = (u8 *)current->stack + i * PAGE_SIZE + offset;
1123                         err_printk(dev, NULL, "device driver maps memory from stack [probable addr=%p]\n", addr);
1124                         break;
1125                 }
1126         }
1127 }
1128
1129 static inline bool overlap(void *addr, unsigned long len, void *start, void *end)
1130 {
1131         unsigned long a1 = (unsigned long)addr;
1132         unsigned long b1 = a1 + len;
1133         unsigned long a2 = (unsigned long)start;
1134         unsigned long b2 = (unsigned long)end;
1135
1136         return !(b1 <= a2 || a1 >= b2);
1137 }
1138
1139 static void check_for_illegal_area(struct device *dev, void *addr, unsigned long len)
1140 {
1141         if (overlap(addr, len, _stext, _etext) ||
1142             overlap(addr, len, __start_rodata, __end_rodata))
1143                 err_printk(dev, NULL, "device driver maps memory from kernel text or rodata [addr=%p] [len=%lu]\n", addr, len);
1144 }
1145
1146 static void check_sync(struct device *dev,
1147                        struct dma_debug_entry *ref,
1148                        bool to_cpu)
1149 {
1150         struct dma_debug_entry *entry;
1151         struct hash_bucket *bucket;
1152         unsigned long flags;
1153
1154         bucket = get_hash_bucket(ref, &flags);
1155
1156         entry = bucket_find_contain(&bucket, ref, &flags);
1157
1158         if (!entry) {
1159                 err_printk(dev, NULL, "device driver tries "
1160                                 "to sync DMA memory it has not allocated "
1161                                 "[device address=0x%016llx] [size=%llu bytes]\n",
1162                                 (unsigned long long)ref->dev_addr, ref->size);
1163                 goto out;
1164         }
1165
1166         if (ref->size > entry->size) {
1167                 err_printk(dev, entry, "device driver syncs"
1168                                 " DMA memory outside allocated range "
1169                                 "[device address=0x%016llx] "
1170                                 "[allocation size=%llu bytes] "
1171                                 "[sync offset+size=%llu]\n",
1172                                 entry->dev_addr, entry->size,
1173                                 ref->size);
1174         }
1175
1176         if (entry->direction == DMA_BIDIRECTIONAL)
1177                 goto out;
1178
1179         if (ref->direction != entry->direction) {
1180                 err_printk(dev, entry, "device driver syncs "
1181                                 "DMA memory with different direction "
1182                                 "[device address=0x%016llx] [size=%llu bytes] "
1183                                 "[mapped with %s] [synced with %s]\n",
1184                                 (unsigned long long)ref->dev_addr, entry->size,
1185                                 dir2name[entry->direction],
1186                                 dir2name[ref->direction]);
1187         }
1188
1189         if (to_cpu && !(entry->direction == DMA_FROM_DEVICE) &&
1190                       !(ref->direction == DMA_TO_DEVICE))
1191                 err_printk(dev, entry, "device driver syncs "
1192                                 "device read-only DMA memory for cpu "
1193                                 "[device address=0x%016llx] [size=%llu bytes] "
1194                                 "[mapped with %s] [synced with %s]\n",
1195                                 (unsigned long long)ref->dev_addr, entry->size,
1196                                 dir2name[entry->direction],
1197                                 dir2name[ref->direction]);
1198
1199         if (!to_cpu && !(entry->direction == DMA_TO_DEVICE) &&
1200                        !(ref->direction == DMA_FROM_DEVICE))
1201                 err_printk(dev, entry, "device driver syncs "
1202                                 "device write-only DMA memory to device "
1203                                 "[device address=0x%016llx] [size=%llu bytes] "
1204                                 "[mapped with %s] [synced with %s]\n",
1205                                 (unsigned long long)ref->dev_addr, entry->size,
1206                                 dir2name[entry->direction],
1207                                 dir2name[ref->direction]);
1208
1209         if (ref->sg_call_ents && ref->type == dma_debug_sg &&
1210             ref->sg_call_ents != entry->sg_call_ents) {
1211                 err_printk(ref->dev, entry, "device driver syncs "
1212                            "DMA sg list with different entry count "
1213                            "[map count=%d] [sync count=%d]\n",
1214                            entry->sg_call_ents, ref->sg_call_ents);
1215         }
1216
1217 out:
1218         put_hash_bucket(bucket, &flags);
1219 }
1220
1221 static void check_sg_segment(struct device *dev, struct scatterlist *sg)
1222 {
1223 #ifdef CONFIG_DMA_API_DEBUG_SG
1224         unsigned int max_seg = dma_get_max_seg_size(dev);
1225         u64 start, end, boundary = dma_get_seg_boundary(dev);
1226
1227         /*
1228          * Either the driver forgot to set dma_parms appropriately, or
1229          * whoever generated the list forgot to check them.
1230          */
1231         if (sg->length > max_seg)
1232                 err_printk(dev, NULL, "mapping sg segment longer than device claims to support [len=%u] [max=%u]\n",
1233                            sg->length, max_seg);
1234         /*
1235          * In some cases this could potentially be the DMA API
1236          * implementation's fault, but it would usually imply that
1237          * the scatterlist was built inappropriately to begin with.
1238          */
1239         start = sg_dma_address(sg);
1240         end = start + sg_dma_len(sg) - 1;
1241         if ((start ^ end) & ~boundary)
1242                 err_printk(dev, NULL, "mapping sg segment across boundary [start=0x%016llx] [end=0x%016llx] [boundary=0x%016llx]\n",
1243                            start, end, boundary);
1244 #endif
1245 }
1246
1247 void debug_dma_map_single(struct device *dev, const void *addr,
1248                             unsigned long len)
1249 {
1250         if (unlikely(dma_debug_disabled()))
1251                 return;
1252
1253         if (!virt_addr_valid(addr))
1254                 err_printk(dev, NULL, "device driver maps memory from invalid area [addr=%p] [len=%lu]\n",
1255                            addr, len);
1256
1257         if (is_vmalloc_addr(addr))
1258                 err_printk(dev, NULL, "device driver maps memory from vmalloc area [addr=%p] [len=%lu]\n",
1259                            addr, len);
1260 }
1261 EXPORT_SYMBOL(debug_dma_map_single);
1262
1263 void debug_dma_map_page(struct device *dev, struct page *page, size_t offset,
1264                         size_t size, int direction, dma_addr_t dma_addr)
1265 {
1266         struct dma_debug_entry *entry;
1267
1268         if (unlikely(dma_debug_disabled()))
1269                 return;
1270
1271         if (dma_mapping_error(dev, dma_addr))
1272                 return;
1273
1274         entry = dma_entry_alloc();
1275         if (!entry)
1276                 return;
1277
1278         entry->dev       = dev;
1279         entry->type      = dma_debug_single;
1280         entry->pfn       = page_to_pfn(page);
1281         entry->offset    = offset,
1282         entry->dev_addr  = dma_addr;
1283         entry->size      = size;
1284         entry->direction = direction;
1285         entry->map_err_type = MAP_ERR_NOT_CHECKED;
1286
1287         check_for_stack(dev, page, offset);
1288
1289         if (!PageHighMem(page)) {
1290                 void *addr = page_address(page) + offset;
1291
1292                 check_for_illegal_area(dev, addr, size);
1293         }
1294
1295         add_dma_entry(entry);
1296 }
1297 EXPORT_SYMBOL(debug_dma_map_page);
1298
1299 void debug_dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
1300 {
1301         struct dma_debug_entry ref;
1302         struct dma_debug_entry *entry;
1303         struct hash_bucket *bucket;
1304         unsigned long flags;
1305
1306         if (unlikely(dma_debug_disabled()))
1307                 return;
1308
1309         ref.dev = dev;
1310         ref.dev_addr = dma_addr;
1311         bucket = get_hash_bucket(&ref, &flags);
1312
1313         list_for_each_entry(entry, &bucket->list, list) {
1314                 if (!exact_match(&ref, entry))
1315                         continue;
1316
1317                 /*
1318                  * The same physical address can be mapped multiple
1319                  * times. Without a hardware IOMMU this results in the
1320                  * same device addresses being put into the dma-debug
1321                  * hash multiple times too. This can result in false
1322                  * positives being reported. Therefore we implement a
1323                  * best-fit algorithm here which updates the first entry
1324                  * from the hash which fits the reference value and is
1325                  * not currently listed as being checked.
1326                  */
1327                 if (entry->map_err_type == MAP_ERR_NOT_CHECKED) {
1328                         entry->map_err_type = MAP_ERR_CHECKED;
1329                         break;
1330                 }
1331         }
1332
1333         put_hash_bucket(bucket, &flags);
1334 }
1335 EXPORT_SYMBOL(debug_dma_mapping_error);
1336
1337 void debug_dma_unmap_page(struct device *dev, dma_addr_t addr,
1338                           size_t size, int direction)
1339 {
1340         struct dma_debug_entry ref = {
1341                 .type           = dma_debug_single,
1342                 .dev            = dev,
1343                 .dev_addr       = addr,
1344                 .size           = size,
1345                 .direction      = direction,
1346         };
1347
1348         if (unlikely(dma_debug_disabled()))
1349                 return;
1350         check_unmap(&ref);
1351 }
1352 EXPORT_SYMBOL(debug_dma_unmap_page);
1353
1354 void debug_dma_map_sg(struct device *dev, struct scatterlist *sg,
1355                       int nents, int mapped_ents, int direction)
1356 {
1357         struct dma_debug_entry *entry;
1358         struct scatterlist *s;
1359         int i;
1360
1361         if (unlikely(dma_debug_disabled()))
1362                 return;
1363
1364         for_each_sg(sg, s, mapped_ents, i) {
1365                 entry = dma_entry_alloc();
1366                 if (!entry)
1367                         return;
1368
1369                 entry->type           = dma_debug_sg;
1370                 entry->dev            = dev;
1371                 entry->pfn            = page_to_pfn(sg_page(s));
1372                 entry->offset         = s->offset,
1373                 entry->size           = sg_dma_len(s);
1374                 entry->dev_addr       = sg_dma_address(s);
1375                 entry->direction      = direction;
1376                 entry->sg_call_ents   = nents;
1377                 entry->sg_mapped_ents = mapped_ents;
1378
1379                 check_for_stack(dev, sg_page(s), s->offset);
1380
1381                 if (!PageHighMem(sg_page(s))) {
1382                         check_for_illegal_area(dev, sg_virt(s), sg_dma_len(s));
1383                 }
1384
1385                 check_sg_segment(dev, s);
1386
1387                 add_dma_entry(entry);
1388         }
1389 }
1390 EXPORT_SYMBOL(debug_dma_map_sg);
1391
1392 static int get_nr_mapped_entries(struct device *dev,
1393                                  struct dma_debug_entry *ref)
1394 {
1395         struct dma_debug_entry *entry;
1396         struct hash_bucket *bucket;
1397         unsigned long flags;
1398         int mapped_ents;
1399
1400         bucket       = get_hash_bucket(ref, &flags);
1401         entry        = bucket_find_exact(bucket, ref);
1402         mapped_ents  = 0;
1403
1404         if (entry)
1405                 mapped_ents = entry->sg_mapped_ents;
1406         put_hash_bucket(bucket, &flags);
1407
1408         return mapped_ents;
1409 }
1410
1411 void debug_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
1412                         int nelems, int dir)
1413 {
1414         struct scatterlist *s;
1415         int mapped_ents = 0, i;
1416
1417         if (unlikely(dma_debug_disabled()))
1418                 return;
1419
1420         for_each_sg(sglist, s, nelems, i) {
1421
1422                 struct dma_debug_entry ref = {
1423                         .type           = dma_debug_sg,
1424                         .dev            = dev,
1425                         .pfn            = page_to_pfn(sg_page(s)),
1426                         .offset         = s->offset,
1427                         .dev_addr       = sg_dma_address(s),
1428                         .size           = sg_dma_len(s),
1429                         .direction      = dir,
1430                         .sg_call_ents   = nelems,
1431                 };
1432
1433                 if (mapped_ents && i >= mapped_ents)
1434                         break;
1435
1436                 if (!i)
1437                         mapped_ents = get_nr_mapped_entries(dev, &ref);
1438
1439                 check_unmap(&ref);
1440         }
1441 }
1442 EXPORT_SYMBOL(debug_dma_unmap_sg);
1443
1444 void debug_dma_alloc_coherent(struct device *dev, size_t size,
1445                               dma_addr_t dma_addr, void *virt)
1446 {
1447         struct dma_debug_entry *entry;
1448
1449         if (unlikely(dma_debug_disabled()))
1450                 return;
1451
1452         if (unlikely(virt == NULL))
1453                 return;
1454
1455         /* handle vmalloc and linear addresses */
1456         if (!is_vmalloc_addr(virt) && !virt_addr_valid(virt))
1457                 return;
1458
1459         entry = dma_entry_alloc();
1460         if (!entry)
1461                 return;
1462
1463         entry->type      = dma_debug_coherent;
1464         entry->dev       = dev;
1465         entry->offset    = offset_in_page(virt);
1466         entry->size      = size;
1467         entry->dev_addr  = dma_addr;
1468         entry->direction = DMA_BIDIRECTIONAL;
1469
1470         if (is_vmalloc_addr(virt))
1471                 entry->pfn = vmalloc_to_pfn(virt);
1472         else
1473                 entry->pfn = page_to_pfn(virt_to_page(virt));
1474
1475         add_dma_entry(entry);
1476 }
1477
1478 void debug_dma_free_coherent(struct device *dev, size_t size,
1479                          void *virt, dma_addr_t addr)
1480 {
1481         struct dma_debug_entry ref = {
1482                 .type           = dma_debug_coherent,
1483                 .dev            = dev,
1484                 .offset         = offset_in_page(virt),
1485                 .dev_addr       = addr,
1486                 .size           = size,
1487                 .direction      = DMA_BIDIRECTIONAL,
1488         };
1489
1490         /* handle vmalloc and linear addresses */
1491         if (!is_vmalloc_addr(virt) && !virt_addr_valid(virt))
1492                 return;
1493
1494         if (is_vmalloc_addr(virt))
1495                 ref.pfn = vmalloc_to_pfn(virt);
1496         else
1497                 ref.pfn = page_to_pfn(virt_to_page(virt));
1498
1499         if (unlikely(dma_debug_disabled()))
1500                 return;
1501
1502         check_unmap(&ref);
1503 }
1504
1505 void debug_dma_map_resource(struct device *dev, phys_addr_t addr, size_t size,
1506                             int direction, dma_addr_t dma_addr)
1507 {
1508         struct dma_debug_entry *entry;
1509
1510         if (unlikely(dma_debug_disabled()))
1511                 return;
1512
1513         entry = dma_entry_alloc();
1514         if (!entry)
1515                 return;
1516
1517         entry->type             = dma_debug_resource;
1518         entry->dev              = dev;
1519         entry->pfn              = PHYS_PFN(addr);
1520         entry->offset           = offset_in_page(addr);
1521         entry->size             = size;
1522         entry->dev_addr         = dma_addr;
1523         entry->direction        = direction;
1524         entry->map_err_type     = MAP_ERR_NOT_CHECKED;
1525
1526         add_dma_entry(entry);
1527 }
1528 EXPORT_SYMBOL(debug_dma_map_resource);
1529
1530 void debug_dma_unmap_resource(struct device *dev, dma_addr_t dma_addr,
1531                               size_t size, int direction)
1532 {
1533         struct dma_debug_entry ref = {
1534                 .type           = dma_debug_resource,
1535                 .dev            = dev,
1536                 .dev_addr       = dma_addr,
1537                 .size           = size,
1538                 .direction      = direction,
1539         };
1540
1541         if (unlikely(dma_debug_disabled()))
1542                 return;
1543
1544         check_unmap(&ref);
1545 }
1546 EXPORT_SYMBOL(debug_dma_unmap_resource);
1547
1548 void debug_dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_handle,
1549                                    size_t size, int direction)
1550 {
1551         struct dma_debug_entry ref;
1552
1553         if (unlikely(dma_debug_disabled()))
1554                 return;
1555
1556         ref.type         = dma_debug_single;
1557         ref.dev          = dev;
1558         ref.dev_addr     = dma_handle;
1559         ref.size         = size;
1560         ref.direction    = direction;
1561         ref.sg_call_ents = 0;
1562
1563         check_sync(dev, &ref, true);
1564 }
1565 EXPORT_SYMBOL(debug_dma_sync_single_for_cpu);
1566
1567 void debug_dma_sync_single_for_device(struct device *dev,
1568                                       dma_addr_t dma_handle, size_t size,
1569                                       int direction)
1570 {
1571         struct dma_debug_entry ref;
1572
1573         if (unlikely(dma_debug_disabled()))
1574                 return;
1575
1576         ref.type         = dma_debug_single;
1577         ref.dev          = dev;
1578         ref.dev_addr     = dma_handle;
1579         ref.size         = size;
1580         ref.direction    = direction;
1581         ref.sg_call_ents = 0;
1582
1583         check_sync(dev, &ref, false);
1584 }
1585 EXPORT_SYMBOL(debug_dma_sync_single_for_device);
1586
1587 void debug_dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
1588                                int nelems, int direction)
1589 {
1590         struct scatterlist *s;
1591         int mapped_ents = 0, i;
1592
1593         if (unlikely(dma_debug_disabled()))
1594                 return;
1595
1596         for_each_sg(sg, s, nelems, i) {
1597
1598                 struct dma_debug_entry ref = {
1599                         .type           = dma_debug_sg,
1600                         .dev            = dev,
1601                         .pfn            = page_to_pfn(sg_page(s)),
1602                         .offset         = s->offset,
1603                         .dev_addr       = sg_dma_address(s),
1604                         .size           = sg_dma_len(s),
1605                         .direction      = direction,
1606                         .sg_call_ents   = nelems,
1607                 };
1608
1609                 if (!i)
1610                         mapped_ents = get_nr_mapped_entries(dev, &ref);
1611
1612                 if (i >= mapped_ents)
1613                         break;
1614
1615                 check_sync(dev, &ref, true);
1616         }
1617 }
1618 EXPORT_SYMBOL(debug_dma_sync_sg_for_cpu);
1619
1620 void debug_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
1621                                   int nelems, int direction)
1622 {
1623         struct scatterlist *s;
1624         int mapped_ents = 0, i;
1625
1626         if (unlikely(dma_debug_disabled()))
1627                 return;
1628
1629         for_each_sg(sg, s, nelems, i) {
1630
1631                 struct dma_debug_entry ref = {
1632                         .type           = dma_debug_sg,
1633                         .dev            = dev,
1634                         .pfn            = page_to_pfn(sg_page(s)),
1635                         .offset         = s->offset,
1636                         .dev_addr       = sg_dma_address(s),
1637                         .size           = sg_dma_len(s),
1638                         .direction      = direction,
1639                         .sg_call_ents   = nelems,
1640                 };
1641                 if (!i)
1642                         mapped_ents = get_nr_mapped_entries(dev, &ref);
1643
1644                 if (i >= mapped_ents)
1645                         break;
1646
1647                 check_sync(dev, &ref, false);
1648         }
1649 }
1650 EXPORT_SYMBOL(debug_dma_sync_sg_for_device);
1651
1652 static int __init dma_debug_driver_setup(char *str)
1653 {
1654         int i;
1655
1656         for (i = 0; i < NAME_MAX_LEN - 1; ++i, ++str) {
1657                 current_driver_name[i] = *str;
1658                 if (*str == 0)
1659                         break;
1660         }
1661
1662         if (current_driver_name[0])
1663                 pr_info("enable driver filter for driver [%s]\n",
1664                         current_driver_name);
1665
1666
1667         return 1;
1668 }
1669 __setup("dma_debug_driver=", dma_debug_driver_setup);