kernel/dma/debug.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Copyright (C) 2008 Advanced Micro Devices, Inc.
   4  *
   5  * Author: Joerg Roedel <joerg.roedel@amd.com>
   6  */
   7
   8 #define pr_fmt(fmt)     "DMA-API: " fmt
   9
  10 #include <linux/sched/task_stack.h>
  11 #include <linux/scatterlist.h>
  12 #include <linux/dma-map-ops.h>
  13 #include <linux/sched/task.h>
  14 #include <linux/stacktrace.h>
  15 #include <linux/spinlock.h>
  16 #include <linux/vmalloc.h>
  17 #include <linux/debugfs.h>
  18 #include <linux/uaccess.h>
  19 #include <linux/export.h>
  20 #include <linux/device.h>
  21 #include <linux/types.h>
  22 #include <linux/sched.h>
  23 #include <linux/ctype.h>
  24 #include <linux/list.h>
  25 #include <linux/slab.h>
  26 #include <asm/sections.h>
  27 #include "debug.h"
  28
  29 #define HASH_SIZE       16384ULL
  30 #define HASH_FN_SHIFT   13
  31 #define HASH_FN_MASK    (HASH_SIZE - 1)
  32
  33 #define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16)
  34 /* If the pool runs out, add this many new entries at once */
  35 #define DMA_DEBUG_DYNAMIC_ENTRIES (PAGE_SIZE / sizeof(struct dma_debug_entry))
  36
  37 enum {
  38         dma_debug_single,
  39         dma_debug_sg,
  40         dma_debug_coherent,
  41         dma_debug_resource,
  42 };
  43
  44 enum map_err_types {
  45         MAP_ERR_CHECK_NOT_APPLICABLE,
  46         MAP_ERR_NOT_CHECKED,
  47         MAP_ERR_CHECKED,
  48 };
  49
  50 #define DMA_DEBUG_STACKTRACE_ENTRIES 5
  51
  52 /**
  53  * struct dma_debug_entry - track a dma_map* or dma_alloc_coherent mapping
  54  * @list: node on pre-allocated free_entries list
  55  * @dev: 'dev' argument to dma_map_{page|single|sg} or dma_alloc_coherent
  56  * @size: length of the mapping
  57  * @type: single, page, sg, coherent
  58  * @direction: enum dma_data_direction
  59  * @sg_call_ents: 'nents' from dma_map_sg
  60  * @sg_mapped_ents: 'mapped_ents' from dma_map_sg
  61  * @pfn: page frame of the start address
  62  * @offset: offset of mapping relative to pfn
  63  * @map_err_type: track whether dma_mapping_error() was checked
  64  * @stacktrace: support backtraces when a violation is detected
  65  */
  66 struct dma_debug_entry {
  67         struct list_head list;
  68         struct device    *dev;
  69         u64              dev_addr;
  70         u64              size;
  71         int              type;
  72         int              direction;
  73         int              sg_call_ents;
  74         int              sg_mapped_ents;
  75         unsigned long    pfn;
  76         size_t           offset;
  77         enum map_err_types  map_err_type;
  78 #ifdef CONFIG_STACKTRACE
  79         unsigned int    stack_len;
  80         unsigned long   stack_entries[DMA_DEBUG_STACKTRACE_ENTRIES];
  81 #endif
  82 } ____cacheline_aligned_in_smp;
  83
  84 typedef bool (*match_fn)(struct dma_debug_entry *, struct dma_debug_entry *);
  85
  86 struct hash_bucket {
  87         struct list_head list;
  88         spinlock_t lock;
  89 };
  90
  91 /* Hash list to save the allocated dma addresses */
  92 static struct hash_bucket dma_entry_hash[HASH_SIZE];
  93 /* List of pre-allocated dma_debug_entry's */
  94 static LIST_HEAD(free_entries);
  95 /* Lock for the list above */
  96 static DEFINE_SPINLOCK(free_entries_lock);
  97
  98 /* Global disable flag - will be set in case of an error */
  99 static bool global_disable __read_mostly;
 100
 101 /* Early initialization disable flag, set at the end of dma_debug_init */
 102 static bool dma_debug_initialized __read_mostly;
 103
 104 static inline bool dma_debug_disabled(void)
 105 {
 106         return global_disable || !dma_debug_initialized;
 107 }
 108
 109 /* Global error count */
 110 static u32 error_count;
 111
 112 /* Global error show enable*/
 113 static u32 show_all_errors __read_mostly;
 114 /* Number of errors to show */
 115 static u32 show_num_errors = 1;
 116
 117 static u32 num_free_entries;
 118 static u32 min_free_entries;
 119 static u32 nr_total_entries;
 120
 121 /* number of preallocated entries requested by kernel cmdline */
 122 static u32 nr_prealloc_entries = PREALLOC_DMA_DEBUG_ENTRIES;
 123
 124 /* per-driver filter related state */
 125
 126 #define NAME_MAX_LEN    64
 127
 128 static char                  current_driver_name[NAME_MAX_LEN] __read_mostly;
 129 static struct device_driver *current_driver                    __read_mostly;
 130
 131 static DEFINE_RWLOCK(driver_name_lock);
 132
 133 static const char *const maperr2str[] = {
 134         [MAP_ERR_CHECK_NOT_APPLICABLE] = "dma map error check not applicable",
 135         [MAP_ERR_NOT_CHECKED] = "dma map error not checked",
 136         [MAP_ERR_CHECKED] = "dma map error checked",
 137 };
 138
 139 static const char *type2name[] = {
 140         [dma_debug_single] = "single",
 141         [dma_debug_sg] = "scather-gather",
 142         [dma_debug_coherent] = "coherent",
 143         [dma_debug_resource] = "resource",
 144 };
 145
 146 static const char *dir2name[] = {
 147         [DMA_BIDIRECTIONAL]     = "DMA_BIDIRECTIONAL",
 148         [DMA_TO_DEVICE]         = "DMA_TO_DEVICE",
 149         [DMA_FROM_DEVICE]       = "DMA_FROM_DEVICE",
 150         [DMA_NONE]              = "DMA_NONE",
 151 };
 152
 153 /*
 154  * The access to some variables in this macro is racy. We can't use atomic_t
 155  * here because all these variables are exported to debugfs. Some of them even
 156  * writeable. This is also the reason why a lock won't help much. But anyway,
 157  * the races are no big deal. Here is why:
 158  *
 159  *   error_count: the addition is racy, but the worst thing that can happen is
 160  *                that we don't count some errors
 161  *   show_num_errors: the subtraction is racy. Also no big deal because in
 162  *                    worst case this will result in one warning more in the
 163  *                    system log than the user configured. This variable is
 164  *                    writeable via debugfs.
 165  */
 166 static inline void dump_entry_trace(struct dma_debug_entry *entry)
 167 {
 168 #ifdef CONFIG_STACKTRACE
 169         if (entry) {
 170                 pr_warn("Mapped at:\n");
 171                 stack_trace_print(entry->stack_entries, entry->stack_len, 0);
 172         }
 173 #endif
 174 }
 175
 176 static bool driver_filter(struct device *dev)
 177 {
 178         struct device_driver *drv;
 179         unsigned long flags;
 180         bool ret;
 181
 182         /* driver filter off */
 183         if (likely(!current_driver_name[0]))
 184                 return true;
 185
 186         /* driver filter on and initialized */
 187         if (current_driver && dev && dev->driver == current_driver)
 188                 return true;
 189
 190         /* driver filter on, but we can't filter on a NULL device... */
 191         if (!dev)
 192                 return false;
 193
 194         if (current_driver || !current_driver_name[0])
 195                 return false;
 196
 197         /* driver filter on but not yet initialized */
 198         drv = dev->driver;
 199         if (!drv)
 200                 return false;
 201
 202         /* lock to protect against change of current_driver_name */
 203         read_lock_irqsave(&driver_name_lock, flags);
 204
 205         ret = false;
 206         if (drv->name &&
 207             strncmp(current_driver_name, drv->name, NAME_MAX_LEN - 1) == 0) {
 208                 current_driver = drv;
 209                 ret = true;
 210         }
 211
 212         read_unlock_irqrestore(&driver_name_lock, flags);
 213
 214         return ret;
 215 }
 216
 217 #define err_printk(dev, entry, format, arg...) do {                     \
 218                 error_count += 1;                                       \
 219                 if (driver_filter(dev) &&                               \
 220                     (show_all_errors || show_num_errors > 0)) {         \
 221                         WARN(1, pr_fmt("%s %s: ") format,               \
 222                              dev ? dev_driver_string(dev) : "NULL",     \
 223                              dev ? dev_name(dev) : "NULL", ## arg);     \
 224                         dump_entry_trace(entry);                        \
 225                 }                                                       \
 226                 if (!show_all_errors && show_num_errors > 0)            \
 227                         show_num_errors -= 1;                           \
 228         } while (0);
 229
 230 /*
 231  * Hash related functions
 232  *
 233  * Every DMA-API request is saved into a struct dma_debug_entry. To
 234  * have quick access to these structs they are stored into a hash.
 235  */
 236 static int hash_fn(struct dma_debug_entry *entry)
 237 {
 238         /*
 239          * Hash function is based on the dma address.
 240          * We use bits 20-27 here as the index into the hash
 241          */
 242         return (entry->dev_addr >> HASH_FN_SHIFT) & HASH_FN_MASK;
 243 }
 244
 245 /*
 246  * Request exclusive access to a hash bucket for a given dma_debug_entry.
 247  */
 248 static struct hash_bucket *get_hash_bucket(struct dma_debug_entry *entry,
 249                                            unsigned long *flags)
 250         __acquires(&dma_entry_hash[idx].lock)
 251 {
 252         int idx = hash_fn(entry);
 253         unsigned long __flags;
 254
 255         spin_lock_irqsave(&dma_entry_hash[idx].lock, __flags);
 256         *flags = __flags;
 257         return &dma_entry_hash[idx];
 258 }
 259
 260 /*
 261  * Give up exclusive access to the hash bucket
 262  */
 263 static void put_hash_bucket(struct hash_bucket *bucket,
 264                             unsigned long flags)
 265         __releases(&bucket->lock)
 266 {
 267         spin_unlock_irqrestore(&bucket->lock, flags);
 268 }
 269
 270 static bool exact_match(struct dma_debug_entry *a, struct dma_debug_entry *b)
 271 {
 272         return ((a->dev_addr == b->dev_addr) &&
 273                 (a->dev == b->dev)) ? true : false;
 274 }
 275
 276 static bool containing_match(struct dma_debug_entry *a,
 277                              struct dma_debug_entry *b)
 278 {
 279         if (a->dev != b->dev)
 280                 return false;
 281
 282         if ((b->dev_addr <= a->dev_addr) &&
 283             ((b->dev_addr + b->size) >= (a->dev_addr + a->size)))
 284                 return true;
 285
 286         return false;
 287 }
 288
 289 /*
 290  * Search a given entry in the hash bucket list
 291  */
 292 static struct dma_debug_entry *__hash_bucket_find(struct hash_bucket *bucket,
 293                                                   struct dma_debug_entry *ref,
 294                                                   match_fn match)
 295 {
 296         struct dma_debug_entry *entry, *ret = NULL;
 297         int matches = 0, match_lvl, last_lvl = -1;
 298
 299         list_for_each_entry(entry, &bucket->list, list) {
 300                 if (!match(ref, entry))
 301                         continue;
 302
 303                 /*
 304                  * Some drivers map the same physical address multiple
 305                  * times. Without a hardware IOMMU this results in the
 306                  * same device addresses being put into the dma-debug
 307                  * hash multiple times too. This can result in false
 308                  * positives being reported. Therefore we implement a
 309                  * best-fit algorithm here which returns the entry from
 310                  * the hash which fits best to the reference value
 311                  * instead of the first-fit.
 312                  */
 313                 matches += 1;
 314                 match_lvl = 0;
 315                 entry->size         == ref->size         ? ++match_lvl : 0;
 316                 entry->type         == ref->type         ? ++match_lvl : 0;
 317                 entry->direction    == ref->direction    ? ++match_lvl : 0;
 318                 entry->sg_call_ents == ref->sg_call_ents ? ++match_lvl : 0;
 319
 320                 if (match_lvl == 4) {
 321                         /* perfect-fit - return the result */
 322                         return entry;
 323                 } else if (match_lvl > last_lvl) {
 324                         /*
 325                          * We found an entry that fits better then the
 326                          * previous one or it is the 1st match.
 327                          */
 328                         last_lvl = match_lvl;
 329                         ret      = entry;
 330                 }
 331         }
 332
 333         /*
 334          * If we have multiple matches but no perfect-fit, just return
 335          * NULL.
 336          */
 337         ret = (matches == 1) ? ret : NULL;
 338
 339         return ret;
 340 }
 341
 342 static struct dma_debug_entry *bucket_find_exact(struct hash_bucket *bucket,
 343                                                  struct dma_debug_entry *ref)
 344 {
 345         return __hash_bucket_find(bucket, ref, exact_match);
 346 }
 347
 348 static struct dma_debug_entry *bucket_find_contain(struct hash_bucket **bucket,
 349                                                    struct dma_debug_entry *ref,
 350                                                    unsigned long *flags)
 351 {
 352
 353         unsigned int max_range = dma_get_max_seg_size(ref->dev);
 354         struct dma_debug_entry *entry, index = *ref;
 355         unsigned int range = 0;
 356
 357         while (range <= max_range) {
 358                 entry = __hash_bucket_find(*bucket, ref, containing_match);
 359
 360                 if (entry)
 361                         return entry;
 362
 363                 /*
 364                  * Nothing found, go back a hash bucket
 365                  */
 366                 put_hash_bucket(*bucket, *flags);
 367                 range          += (1 << HASH_FN_SHIFT);
 368                 index.dev_addr -= (1 << HASH_FN_SHIFT);
 369                 *bucket = get_hash_bucket(&index, flags);
 370         }
 371
 372         return NULL;
 373 }
 374
 375 /*
 376  * Add an entry to a hash bucket
 377  */
 378 static void hash_bucket_add(struct hash_bucket *bucket,
 379                             struct dma_debug_entry *entry)
 380 {
 381         list_add_tail(&entry->list, &bucket->list);
 382 }
 383
 384 /*
 385  * Remove entry from a hash bucket list
 386  */
 387 static void hash_bucket_del(struct dma_debug_entry *entry)
 388 {
 389         list_del(&entry->list);
 390 }
 391
 392 static unsigned long long phys_addr(struct dma_debug_entry *entry)
 393 {
 394         if (entry->type == dma_debug_resource)
 395                 return __pfn_to_phys(entry->pfn) + entry->offset;
 396
 397         return page_to_phys(pfn_to_page(entry->pfn)) + entry->offset;
 398 }
 399
 400 /*
 401  * Dump mapping entries for debugging purposes
 402  */
 403 void debug_dma_dump_mappings(struct device *dev)
 404 {
 405         int idx;
 406
 407         for (idx = 0; idx < HASH_SIZE; idx++) {
 408                 struct hash_bucket *bucket = &dma_entry_hash[idx];
 409                 struct dma_debug_entry *entry;
 410                 unsigned long flags;
 411
 412                 spin_lock_irqsave(&bucket->lock, flags);
 413
 414                 list_for_each_entry(entry, &bucket->list, list) {
 415                         if (!dev || dev == entry->dev) {
 416                                 dev_info(entry->dev,
 417                                          "%s idx %d P=%Lx N=%lx D=%Lx L=%Lx %s %s\n",
 418                                          type2name[entry->type], idx,
 419                                          phys_addr(entry), entry->pfn,
 420                                          entry->dev_addr, entry->size,
 421                                          dir2name[entry->direction],
 422                                          maperr2str[entry->map_err_type]);
 423                         }
 424                 }
 425
 426                 spin_unlock_irqrestore(&bucket->lock, flags);
 427                 cond_resched();
 428         }
 429 }
 430
 431 /*
 432  * For each mapping (initial cacheline in the case of
 433  * dma_alloc_coherent/dma_map_page, initial cacheline in each page of a
 434  * scatterlist, or the cacheline specified in dma_map_single) insert
 435  * into this tree using the cacheline as the key. At
 436  * dma_unmap_{single|sg|page} or dma_free_coherent delete the entry.  If
 437  * the entry already exists at insertion time add a tag as a reference
 438  * count for the overlapping mappings.  For now, the overlap tracking
 439  * just ensures that 'unmaps' balance 'maps' before marking the
 440  * cacheline idle, but we should also be flagging overlaps as an API
 441  * violation.
 442  *
 443  * Memory usage is mostly constrained by the maximum number of available
 444  * dma-debug entries in that we need a free dma_debug_entry before
 445  * inserting into the tree.  In the case of dma_map_page and
 446  * dma_alloc_coherent there is only one dma_debug_entry and one
 447  * dma_active_cacheline entry to track per event.  dma_map_sg(), on the
 448  * other hand, consumes a single dma_debug_entry, but inserts 'nents'
 449  * entries into the tree.
 450  */
 451 static RADIX_TREE(dma_active_cacheline, GFP_ATOMIC);
 452 static DEFINE_SPINLOCK(radix_lock);
 453 #define ACTIVE_CACHELINE_MAX_OVERLAP ((1 << RADIX_TREE_MAX_TAGS) - 1)
 454 #define CACHELINE_PER_PAGE_SHIFT (PAGE_SHIFT - L1_CACHE_SHIFT)
 455 #define CACHELINES_PER_PAGE (1 << CACHELINE_PER_PAGE_SHIFT)
 456
 457 static phys_addr_t to_cacheline_number(struct dma_debug_entry *entry)
 458 {
 459         return (entry->pfn << CACHELINE_PER_PAGE_SHIFT) +
 460                 (entry->offset >> L1_CACHE_SHIFT);
 461 }
 462
 463 static int active_cacheline_read_overlap(phys_addr_t cln)
 464 {
 465         int overlap = 0, i;
 466
 467         for (i = RADIX_TREE_MAX_TAGS - 1; i >= 0; i--)
 468                 if (radix_tree_tag_get(&dma_active_cacheline, cln, i))
 469                         overlap |= 1 << i;
 470         return overlap;
 471 }
 472
 473 static int active_cacheline_set_overlap(phys_addr_t cln, int overlap)
 474 {
 475         int i;
 476
 477         if (overlap > ACTIVE_CACHELINE_MAX_OVERLAP || overlap < 0)
 478                 return overlap;
 479
 480         for (i = RADIX_TREE_MAX_TAGS - 1; i >= 0; i--)
 481                 if (overlap & 1 << i)
 482                         radix_tree_tag_set(&dma_active_cacheline, cln, i);
 483                 else
 484                         radix_tree_tag_clear(&dma_active_cacheline, cln, i);
 485
 486         return overlap;
 487 }
 488
 489 static void active_cacheline_inc_overlap(phys_addr_t cln)
 490 {
 491         int overlap = active_cacheline_read_overlap(cln);
 492
 493         overlap = active_cacheline_set_overlap(cln, ++overlap);
 494
 495         /* If we overflowed the overlap counter then we're potentially
 496          * leaking dma-mappings.
 497          */
 498         WARN_ONCE(overlap > ACTIVE_CACHELINE_MAX_OVERLAP,
 499                   pr_fmt("exceeded %d overlapping mappings of cacheline %pa\n"),
 500                   ACTIVE_CACHELINE_MAX_OVERLAP, &cln);
 501 }
 502
 503 static int active_cacheline_dec_overlap(phys_addr_t cln)
 504 {
 505         int overlap = active_cacheline_read_overlap(cln);
 506
 507         return active_cacheline_set_overlap(cln, --overlap);
 508 }
 509
 510 static int active_cacheline_insert(struct dma_debug_entry *entry)
 511 {
 512         phys_addr_t cln = to_cacheline_number(entry);
 513         unsigned long flags;
 514         int rc;
 515
 516         /* If the device is not writing memory then we don't have any
 517          * concerns about the cpu consuming stale data.  This mitigates
 518          * legitimate usages of overlapping mappings.
 519          */
 520         if (entry->direction == DMA_TO_DEVICE)
 521                 return 0;
 522
 523         spin_lock_irqsave(&radix_lock, flags);
 524         rc = radix_tree_insert(&dma_active_cacheline, cln, entry);
 525         if (rc == -EEXIST)
 526                 active_cacheline_inc_overlap(cln);
 527         spin_unlock_irqrestore(&radix_lock, flags);
 528
 529         return rc;
 530 }
 531
 532 static void active_cacheline_remove(struct dma_debug_entry *entry)
 533 {
 534         phys_addr_t cln = to_cacheline_number(entry);
 535         unsigned long flags;
 536
 537         /* ...mirror the insert case */
 538         if (entry->direction == DMA_TO_DEVICE)
 539                 return;
 540
 541         spin_lock_irqsave(&radix_lock, flags);
 542         /* since we are counting overlaps the final put of the
 543          * cacheline will occur when the overlap count is 0.
 544          * active_cacheline_dec_overlap() returns -1 in that case
 545          */
 546         if (active_cacheline_dec_overlap(cln) < 0)
 547                 radix_tree_delete(&dma_active_cacheline, cln);
 548         spin_unlock_irqrestore(&radix_lock, flags);
 549 }
 550
 551 /*
 552  * Wrapper function for adding an entry to the hash.
 553  * This function takes care of locking itself.
 554  */
 555 static void add_dma_entry(struct dma_debug_entry *entry)
 556 {
 557         struct hash_bucket *bucket;
 558         unsigned long flags;
 559         int rc;
 560
 561         bucket = get_hash_bucket(entry, &flags);
 562         hash_bucket_add(bucket, entry);
 563         put_hash_bucket(bucket, flags);
 564
 565         rc = active_cacheline_insert(entry);
 566         if (rc == -ENOMEM) {
 567                 pr_err_once("cacheline tracking ENOMEM, dma-debug disabled\n");
 568                 global_disable = true;
 569         }
 570
 571         /* TODO: report -EEXIST errors here as overlapping mappings are
 572          * not supported by the DMA API
 573          */
 574 }
 575
 576 static int dma_debug_create_entries(gfp_t gfp)
 577 {
 578         struct dma_debug_entry *entry;
 579         int i;
 580
 581         entry = (void *)get_zeroed_page(gfp);
 582         if (!entry)
 583                 return -ENOMEM;
 584
 585         for (i = 0; i < DMA_DEBUG_DYNAMIC_ENTRIES; i++)
 586                 list_add_tail(&entry[i].list, &free_entries);
 587
 588         num_free_entries += DMA_DEBUG_DYNAMIC_ENTRIES;
 589         nr_total_entries += DMA_DEBUG_DYNAMIC_ENTRIES;
 590
 591         return 0;
 592 }
 593
 594 static struct dma_debug_entry *__dma_entry_alloc(void)
 595 {
 596         struct dma_debug_entry *entry;
 597
 598         entry = list_entry(free_entries.next, struct dma_debug_entry, list);
 599         list_del(&entry->list);
 600         memset(entry, 0, sizeof(*entry));
 601
 602         num_free_entries -= 1;
 603         if (num_free_entries < min_free_entries)
 604                 min_free_entries = num_free_entries;
 605
 606         return entry;
 607 }
 608
 609 /*
 610  * This should be called outside of free_entries_lock scope to avoid potential
 611  * deadlocks with serial consoles that use DMA.
 612  */
 613 static void __dma_entry_alloc_check_leak(u32 nr_entries)
 614 {
 615         u32 tmp = nr_entries % nr_prealloc_entries;
 616
 617         /* Shout each time we tick over some multiple of the initial pool */
 618         if (tmp < DMA_DEBUG_DYNAMIC_ENTRIES) {
 619                 pr_info("dma_debug_entry pool grown to %u (%u00%%)\n",
 620                         nr_entries,
 621                         (nr_entries / nr_prealloc_entries));
 622         }
 623 }
 624
 625 /* struct dma_entry allocator
 626  *
 627  * The next two functions implement the allocator for
 628  * struct dma_debug_entries.
 629  */
 630 static struct dma_debug_entry *dma_entry_alloc(void)
 631 {
 632         bool alloc_check_leak = false;
 633         struct dma_debug_entry *entry;
 634         unsigned long flags;
 635         u32 nr_entries;
 636
 637         spin_lock_irqsave(&free_entries_lock, flags);
 638         if (num_free_entries == 0) {
 639                 if (dma_debug_create_entries(GFP_ATOMIC)) {
 640                         global_disable = true;
 641                         spin_unlock_irqrestore(&free_entries_lock, flags);
 642                         pr_err("debugging out of memory - disabling\n");
 643                         return NULL;
 644                 }
 645                 alloc_check_leak = true;
 646                 nr_entries = nr_total_entries;
 647         }
 648
 649         entry = __dma_entry_alloc();
 650
 651         spin_unlock_irqrestore(&free_entries_lock, flags);
 652
 653         if (alloc_check_leak)
 654                 __dma_entry_alloc_check_leak(nr_entries);
 655
 656 #ifdef CONFIG_STACKTRACE
 657         entry->stack_len = stack_trace_save(entry->stack_entries,
 658                                             ARRAY_SIZE(entry->stack_entries),
 659                                             1);
 660 #endif
 661         return entry;
 662 }
 663
 664 static void dma_entry_free(struct dma_debug_entry *entry)
 665 {
 666         unsigned long flags;
 667
 668         active_cacheline_remove(entry);
 669
 670         /*
 671          * add to beginning of the list - this way the entries are
 672          * more likely cache hot when they are reallocated.
 673          */
 674         spin_lock_irqsave(&free_entries_lock, flags);
 675         list_add(&entry->list, &free_entries);
 676         num_free_entries += 1;
 677         spin_unlock_irqrestore(&free_entries_lock, flags);
 678 }
 679
 680 /*
 681  * DMA-API debugging init code
 682  *
 683  * The init code does two things:
 684  *   1. Initialize core data structures
 685  *   2. Preallocate a given number of dma_debug_entry structs
 686  */
 687
 688 static ssize_t filter_read(struct file *file, char __user *user_buf,
 689                            size_t count, loff_t *ppos)
 690 {
 691         char buf[NAME_MAX_LEN + 1];
 692         unsigned long flags;
 693         int len;
 694
 695         if (!current_driver_name[0])
 696                 return 0;
 697
 698         /*
 699          * We can't copy to userspace directly because current_driver_name can
 700          * only be read under the driver_name_lock with irqs disabled. So
 701          * create a temporary copy first.
 702          */
 703         read_lock_irqsave(&driver_name_lock, flags);
 704         len = scnprintf(buf, NAME_MAX_LEN + 1, "%s\n", current_driver_name);
 705         read_unlock_irqrestore(&driver_name_lock, flags);
 706
 707         return simple_read_from_buffer(user_buf, count, ppos, buf, len);
 708 }
 709
 710 static ssize_t filter_write(struct file *file, const char __user *userbuf,
 711                             size_t count, loff_t *ppos)
 712 {
 713         char buf[NAME_MAX_LEN];
 714         unsigned long flags;
 715         size_t len;
 716         int i;
 717
 718         /*
 719          * We can't copy from userspace directly. Access to
 720          * current_driver_name is protected with a write_lock with irqs
 721          * disabled. Since copy_from_user can fault and may sleep we
 722          * need to copy to temporary buffer first
 723          */
 724         len = min(count, (size_t)(NAME_MAX_LEN - 1));
 725         if (copy_from_user(buf, userbuf, len))
 726                 return -EFAULT;
 727
 728         buf[len] = 0;
 729
 730         write_lock_irqsave(&driver_name_lock, flags);
 731
 732         /*
 733          * Now handle the string we got from userspace very carefully.
 734          * The rules are:
 735          *         - only use the first token we got
 736          *         - token delimiter is everything looking like a space
 737          *           character (' ', '\n', '\t' ...)
 738          *
 739          */
 740         if (!isalnum(buf[0])) {
 741                 /*
 742                  * If the first character userspace gave us is not
 743                  * alphanumerical then assume the filter should be
 744                  * switched off.
 745                  */
 746                 if (current_driver_name[0])
 747                         pr_info("switching off dma-debug driver filter\n");
 748                 current_driver_name[0] = 0;
 749                 current_driver = NULL;
 750                 goto out_unlock;
 751         }
 752
 753         /*
 754          * Now parse out the first token and use it as the name for the
 755          * driver to filter for.
 756          */
 757         for (i = 0; i < NAME_MAX_LEN - 1; ++i) {
 758                 current_driver_name[i] = buf[i];
 759                 if (isspace(buf[i]) || buf[i] == ' ' || buf[i] == 0)
 760                         break;
 761         }
 762         current_driver_name[i] = 0;
 763         current_driver = NULL;
 764
 765         pr_info("enable driver filter for driver [%s]\n",
 766                 current_driver_name);
 767
 768 out_unlock:
 769         write_unlock_irqrestore(&driver_name_lock, flags);
 770
 771         return count;
 772 }
 773
 774 static const struct file_operations filter_fops = {
 775         .read  = filter_read,
 776         .write = filter_write,
 777         .llseek = default_llseek,
 778 };
 779
 780 static int dump_show(struct seq_file *seq, void *v)
 781 {
 782         int idx;
 783
 784         for (idx = 0; idx < HASH_SIZE; idx++) {
 785                 struct hash_bucket *bucket = &dma_entry_hash[idx];
 786                 struct dma_debug_entry *entry;
 787                 unsigned long flags;
 788
 789                 spin_lock_irqsave(&bucket->lock, flags);
 790                 list_for_each_entry(entry, &bucket->list, list) {
 791                         seq_printf(seq,
 792                                    "%s %s %s idx %d P=%llx N=%lx D=%llx L=%llx %s %s\n",
 793                                    dev_name(entry->dev),
 794                                    dev_driver_string(entry->dev),
 795                                    type2name[entry->type], idx,
 796                                    phys_addr(entry), entry->pfn,
 797                                    entry->dev_addr, entry->size,
 798                                    dir2name[entry->direction],
 799                                    maperr2str[entry->map_err_type]);
 800                 }
 801                 spin_unlock_irqrestore(&bucket->lock, flags);
 802         }
 803         return 0;
 804 }
 805 DEFINE_SHOW_ATTRIBUTE(dump);
 806
 807 static int __init dma_debug_fs_init(void)
 808 {
 809         struct dentry *dentry = debugfs_create_dir("dma-api", NULL);
 810
 811         debugfs_create_bool("disabled", 0444, dentry, &global_disable);
 812         debugfs_create_u32("error_count", 0444, dentry, &error_count);
 813         debugfs_create_u32("all_errors", 0644, dentry, &show_all_errors);
 814         debugfs_create_u32("num_errors", 0644, dentry, &show_num_errors);
 815         debugfs_create_u32("num_free_entries", 0444, dentry, &num_free_entries);
 816         debugfs_create_u32("min_free_entries", 0444, dentry, &min_free_entries);
 817         debugfs_create_u32("nr_total_entries", 0444, dentry, &nr_total_entries);
 818         debugfs_create_file("driver_filter", 0644, dentry, NULL, &filter_fops);
 819         debugfs_create_file("dump", 0444, dentry, NULL, &dump_fops);
 820
 821         return 0;
 822 }
 823 core_initcall_sync(dma_debug_fs_init);
 824
 825 static int device_dma_allocations(struct device *dev, struct dma_debug_entry **out_entry)
 826 {
 827         struct dma_debug_entry *entry;
 828         unsigned long flags;
 829         int count = 0, i;
 830
 831         for (i = 0; i < HASH_SIZE; ++i) {
 832                 spin_lock_irqsave(&dma_entry_hash[i].lock, flags);
 833                 list_for_each_entry(entry, &dma_entry_hash[i].list, list) {
 834                         if (entry->dev == dev) {
 835                                 count += 1;
 836                                 *out_entry = entry;
 837                         }
 838                 }
 839                 spin_unlock_irqrestore(&dma_entry_hash[i].lock, flags);
 840         }
 841
 842         return count;
 843 }
 844
 845 static int dma_debug_device_change(struct notifier_block *nb, unsigned long action, void *data)
 846 {
 847         struct device *dev = data;
 848         struct dma_debug_entry *entry;
 849         int count;
 850
 851         if (dma_debug_disabled())
 852                 return 0;
 853
 854         switch (action) {
 855         case BUS_NOTIFY_UNBOUND_DRIVER:
 856                 count = device_dma_allocations(dev, &entry);
 857                 if (count == 0)
 858                         break;
 859                 err_printk(dev, entry, "device driver has pending "
 860                                 "DMA allocations while released from device "
 861                                 "[count=%d]\n"
 862                                 "One of leaked entries details: "
 863                                 "[device address=0x%016llx] [size=%llu bytes] "
 864                                 "[mapped with %s] [mapped as %s]\n",
 865                         count, entry->dev_addr, entry->size,
 866                         dir2name[entry->direction], type2name[entry->type]);
 867                 break;
 868         default:
 869                 break;
 870         }
 871
 872         return 0;
 873 }
 874
 875 void dma_debug_add_bus(struct bus_type *bus)
 876 {
 877         struct notifier_block *nb;
 878
 879         if (dma_debug_disabled())
 880                 return;
 881
 882         nb = kzalloc(sizeof(struct notifier_block), GFP_KERNEL);
 883         if (nb == NULL) {
 884                 pr_err("dma_debug_add_bus: out of memory\n");
 885                 return;
 886         }
 887
 888         nb->notifier_call = dma_debug_device_change;
 889
 890         bus_register_notifier(bus, nb);
 891 }
 892
 893 static int dma_debug_init(void)
 894 {
 895         int i, nr_pages;
 896
 897         /* Do not use dma_debug_initialized here, since we really want to be
 898          * called to set dma_debug_initialized
 899          */
 900         if (global_disable)
 901                 return 0;
 902
 903         for (i = 0; i < HASH_SIZE; ++i) {
 904                 INIT_LIST_HEAD(&dma_entry_hash[i].list);
 905                 spin_lock_init(&dma_entry_hash[i].lock);
 906         }
 907
 908         nr_pages = DIV_ROUND_UP(nr_prealloc_entries, DMA_DEBUG_DYNAMIC_ENTRIES);
 909         for (i = 0; i < nr_pages; ++i)
 910                 dma_debug_create_entries(GFP_KERNEL);
 911         if (num_free_entries >= nr_prealloc_entries) {
 912                 pr_info("preallocated %d debug entries\n", nr_total_entries);
 913         } else if (num_free_entries > 0) {
 914                 pr_warn("%d debug entries requested but only %d allocated\n",
 915                         nr_prealloc_entries, nr_total_entries);
 916         } else {
 917                 pr_err("debugging out of memory error - disabled\n");
 918                 global_disable = true;
 919
 920                 return 0;
 921         }
 922         min_free_entries = num_free_entries;
 923
 924         dma_debug_initialized = true;
 925
 926         pr_info("debugging enabled by kernel config\n");
 927         return 0;
 928 }
 929 core_initcall(dma_debug_init);
 930
 931 static __init int dma_debug_cmdline(char *str)
 932 {
 933         if (!str)
 934                 return -EINVAL;
 935
 936         if (strncmp(str, "off", 3) == 0) {
 937                 pr_info("debugging disabled on kernel command line\n");
 938                 global_disable = true;
 939         }
 940
 941         return 1;
 942 }
 943
 944 static __init int dma_debug_entries_cmdline(char *str)
 945 {
 946         if (!str)
 947                 return -EINVAL;
 948         if (!get_option(&str, &nr_prealloc_entries))
 949                 nr_prealloc_entries = PREALLOC_DMA_DEBUG_ENTRIES;
 950         return 1;
 951 }
 952
 953 __setup("dma_debug=", dma_debug_cmdline);
 954 __setup("dma_debug_entries=", dma_debug_entries_cmdline);
 955
 956 static void check_unmap(struct dma_debug_entry *ref)
 957 {
 958         struct dma_debug_entry *entry;
 959         struct hash_bucket *bucket;
 960         unsigned long flags;
 961
 962         bucket = get_hash_bucket(ref, &flags);
 963         entry = bucket_find_exact(bucket, ref);
 964
 965         if (!entry) {
 966                 /* must drop lock before calling dma_mapping_error */
 967                 put_hash_bucket(bucket, flags);
 968
 969                 if (dma_mapping_error(ref->dev, ref->dev_addr)) {
 970                         err_printk(ref->dev, NULL,
 971                                    "device driver tries to free an "
 972                                    "invalid DMA memory address\n");
 973                 } else {
 974                         err_printk(ref->dev, NULL,
 975                                    "device driver tries to free DMA "
 976                                    "memory it has not allocated [device "
 977                                    "address=0x%016llx] [size=%llu bytes]\n",
 978                                    ref->dev_addr, ref->size);
 979                 }
 980                 return;
 981         }
 982
 983         if (ref->size != entry->size) {
 984                 err_printk(ref->dev, entry, "device driver frees "
 985                            "DMA memory with different size "
 986                            "[device address=0x%016llx] [map size=%llu bytes] "
 987                            "[unmap size=%llu bytes]\n",
 988                            ref->dev_addr, entry->size, ref->size);
 989         }
 990
 991         if (ref->type != entry->type) {
 992                 err_printk(ref->dev, entry, "device driver frees "
 993                            "DMA memory with wrong function "
 994                            "[device address=0x%016llx] [size=%llu bytes] "
 995                            "[mapped as %s] [unmapped as %s]\n",
 996                            ref->dev_addr, ref->size,
 997                            type2name[entry->type], type2name[ref->type]);
 998         } else if ((entry->type == dma_debug_coherent) &&
 999                    (phys_addr(ref) != phys_addr(entry))) {
1000                 err_printk(ref->dev, entry, "device driver frees "
1001                            "DMA memory with different CPU address "
1002                            "[device address=0x%016llx] [size=%llu bytes] "
1003                            "[cpu alloc address=0x%016llx] "
1004                            "[cpu free address=0x%016llx]",
1005                            ref->dev_addr, ref->size,
1006                            phys_addr(entry),
1007                            phys_addr(ref));
1008         }
1009
1010         if (ref->sg_call_ents && ref->type == dma_debug_sg &&
1011             ref->sg_call_ents != entry->sg_call_ents) {
1012                 err_printk(ref->dev, entry, "device driver frees "
1013                            "DMA sg list with different entry count "
1014                            "[map count=%d] [unmap count=%d]\n",
1015                            entry->sg_call_ents, ref->sg_call_ents);
1016         }
1017
1018         /*
1019          * This may be no bug in reality - but most implementations of the
1020          * DMA API don't handle this properly, so check for it here
1021          */
1022         if (ref->direction != entry->direction) {
1023                 err_printk(ref->dev, entry, "device driver frees "
1024                            "DMA memory with different direction "
1025                            "[device address=0x%016llx] [size=%llu bytes] "
1026                            "[mapped with %s] [unmapped with %s]\n",
1027                            ref->dev_addr, ref->size,
1028                            dir2name[entry->direction],
1029                            dir2name[ref->direction]);
1030         }
1031
1032         /*
1033          * Drivers should use dma_mapping_error() to check the returned
1034          * addresses of dma_map_single() and dma_map_page().
1035          * If not, print this warning message. See Documentation/core-api/dma-api.rst.
1036          */
1037         if (entry->map_err_type == MAP_ERR_NOT_CHECKED) {
1038                 err_printk(ref->dev, entry,
1039                            "device driver failed to check map error"
1040                            "[device address=0x%016llx] [size=%llu bytes] "
1041                            "[mapped as %s]",
1042                            ref->dev_addr, ref->size,
1043                            type2name[entry->type]);
1044         }
1045
1046         hash_bucket_del(entry);
1047         dma_entry_free(entry);
1048
1049         put_hash_bucket(bucket, flags);
1050 }
1051
1052 static void check_for_stack(struct device *dev,
1053                             struct page *page, size_t offset)
1054 {
1055         void *addr;
1056         struct vm_struct *stack_vm_area = task_stack_vm_area(current);
1057
1058         if (!stack_vm_area) {
1059                 /* Stack is direct-mapped. */
1060                 if (PageHighMem(page))
1061                         return;
1062                 addr = page_address(page) + offset;
1063                 if (object_is_on_stack(addr))
1064                         err_printk(dev, NULL, "device driver maps memory from stack [addr=%p]\n", addr);
1065         } else {
1066                 /* Stack is vmalloced. */
1067                 int i;
1068
1069                 for (i = 0; i < stack_vm_area->nr_pages; i++) {
1070                         if (page != stack_vm_area->pages[i])
1071                                 continue;
1072
1073                         addr = (u8 *)current->stack + i * PAGE_SIZE + offset;
1074                         err_printk(dev, NULL, "device driver maps memory from stack [probable addr=%p]\n", addr);
1075                         break;
1076                 }
1077         }
1078 }
1079
1080 static inline bool overlap(void *addr, unsigned long len, void *start, void *end)
1081 {
1082         unsigned long a1 = (unsigned long)addr;
1083         unsigned long b1 = a1 + len;
1084         unsigned long a2 = (unsigned long)start;
1085         unsigned long b2 = (unsigned long)end;
1086
1087         return !(b1 <= a2 || a1 >= b2);
1088 }
1089
1090 static void check_for_illegal_area(struct device *dev, void *addr, unsigned long len)
1091 {
1092         if (overlap(addr, len, _stext, _etext) ||
1093             overlap(addr, len, __start_rodata, __end_rodata))
1094                 err_printk(dev, NULL, "device driver maps memory from kernel text or rodata [addr=%p] [len=%lu]\n", addr, len);
1095 }
1096
1097 static void check_sync(struct device *dev,
1098                        struct dma_debug_entry *ref,
1099                        bool to_cpu)
1100 {
1101         struct dma_debug_entry *entry;
1102         struct hash_bucket *bucket;
1103         unsigned long flags;
1104
1105         bucket = get_hash_bucket(ref, &flags);
1106
1107         entry = bucket_find_contain(&bucket, ref, &flags);
1108
1109         if (!entry) {
1110                 err_printk(dev, NULL, "device driver tries "
1111                                 "to sync DMA memory it has not allocated "
1112                                 "[device address=0x%016llx] [size=%llu bytes]\n",
1113                                 (unsigned long long)ref->dev_addr, ref->size);
1114                 goto out;
1115         }
1116
1117         if (ref->size > entry->size) {
1118                 err_printk(dev, entry, "device driver syncs"
1119                                 " DMA memory outside allocated range "
1120                                 "[device address=0x%016llx] "
1121                                 "[allocation size=%llu bytes] "
1122                                 "[sync offset+size=%llu]\n",
1123                                 entry->dev_addr, entry->size,
1124                                 ref->size);
1125         }
1126
1127         if (entry->direction == DMA_BIDIRECTIONAL)
1128                 goto out;
1129
1130         if (ref->direction != entry->direction) {
1131                 err_printk(dev, entry, "device driver syncs "
1132                                 "DMA memory with different direction "
1133                                 "[device address=0x%016llx] [size=%llu bytes] "
1134                                 "[mapped with %s] [synced with %s]\n",
1135                                 (unsigned long long)ref->dev_addr, entry->size,
1136                                 dir2name[entry->direction],
1137                                 dir2name[ref->direction]);
1138         }
1139
1140         if (to_cpu && !(entry->direction == DMA_FROM_DEVICE) &&
1141                       !(ref->direction == DMA_TO_DEVICE))
1142                 err_printk(dev, entry, "device driver syncs "
1143                                 "device read-only DMA memory for cpu "
1144                                 "[device address=0x%016llx] [size=%llu bytes] "
1145                                 "[mapped with %s] [synced with %s]\n",
1146                                 (unsigned long long)ref->dev_addr, entry->size,
1147                                 dir2name[entry->direction],
1148                                 dir2name[ref->direction]);
1149
1150         if (!to_cpu && !(entry->direction == DMA_TO_DEVICE) &&
1151                        !(ref->direction == DMA_FROM_DEVICE))
1152                 err_printk(dev, entry, "device driver syncs "
1153                                 "device write-only DMA memory to device "
1154                                 "[device address=0x%016llx] [size=%llu bytes] "
1155                                 "[mapped with %s] [synced with %s]\n",
1156                                 (unsigned long long)ref->dev_addr, entry->size,
1157                                 dir2name[entry->direction],
1158                                 dir2name[ref->direction]);
1159
1160         if (ref->sg_call_ents && ref->type == dma_debug_sg &&
1161             ref->sg_call_ents != entry->sg_call_ents) {
1162                 err_printk(ref->dev, entry, "device driver syncs "
1163                            "DMA sg list with different entry count "
1164                            "[map count=%d] [sync count=%d]\n",
1165                            entry->sg_call_ents, ref->sg_call_ents);
1166         }
1167
1168 out:
1169         put_hash_bucket(bucket, flags);
1170 }
1171
1172 static void check_sg_segment(struct device *dev, struct scatterlist *sg)
1173 {
1174 #ifdef CONFIG_DMA_API_DEBUG_SG
1175         unsigned int max_seg = dma_get_max_seg_size(dev);
1176         u64 start, end, boundary = dma_get_seg_boundary(dev);
1177
1178         /*
1179          * Either the driver forgot to set dma_parms appropriately, or
1180          * whoever generated the list forgot to check them.
1181          */
1182         if (sg->length > max_seg)
1183                 err_printk(dev, NULL, "mapping sg segment longer than device claims to support [len=%u] [max=%u]\n",
1184                            sg->length, max_seg);
1185         /*
1186          * In some cases this could potentially be the DMA API
1187          * implementation's fault, but it would usually imply that
1188          * the scatterlist was built inappropriately to begin with.
1189          */
1190         start = sg_dma_address(sg);
1191         end = start + sg_dma_len(sg) - 1;
1192         if ((start ^ end) & ~boundary)
1193                 err_printk(dev, NULL, "mapping sg segment across boundary [start=0x%016llx] [end=0x%016llx] [boundary=0x%016llx]\n",
1194                            start, end, boundary);
1195 #endif
1196 }
1197
1198 void debug_dma_map_single(struct device *dev, const void *addr,
1199                             unsigned long len)
1200 {
1201         if (unlikely(dma_debug_disabled()))
1202                 return;
1203
1204         if (!virt_addr_valid(addr))
1205                 err_printk(dev, NULL, "device driver maps memory from invalid area [addr=%p] [len=%lu]\n",
1206                            addr, len);
1207
1208         if (is_vmalloc_addr(addr))
1209                 err_printk(dev, NULL, "device driver maps memory from vmalloc area [addr=%p] [len=%lu]\n",
1210                            addr, len);
1211 }
1212 EXPORT_SYMBOL(debug_dma_map_single);
1213
1214 void debug_dma_map_page(struct device *dev, struct page *page, size_t offset,
1215                         size_t size, int direction, dma_addr_t dma_addr)
1216 {
1217         struct dma_debug_entry *entry;
1218
1219         if (unlikely(dma_debug_disabled()))
1220                 return;
1221
1222         if (dma_mapping_error(dev, dma_addr))
1223                 return;
1224
1225         entry = dma_entry_alloc();
1226         if (!entry)
1227                 return;
1228
1229         entry->dev       = dev;
1230         entry->type      = dma_debug_single;
1231         entry->pfn       = page_to_pfn(page);
1232         entry->offset    = offset;
1233         entry->dev_addr  = dma_addr;
1234         entry->size      = size;
1235         entry->direction = direction;
1236         entry->map_err_type = MAP_ERR_NOT_CHECKED;
1237
1238         check_for_stack(dev, page, offset);
1239
1240         if (!PageHighMem(page)) {
1241                 void *addr = page_address(page) + offset;
1242
1243                 check_for_illegal_area(dev, addr, size);
1244         }
1245
1246         add_dma_entry(entry);
1247 }
1248
1249 void debug_dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
1250 {
1251         struct dma_debug_entry ref;
1252         struct dma_debug_entry *entry;
1253         struct hash_bucket *bucket;
1254         unsigned long flags;
1255
1256         if (unlikely(dma_debug_disabled()))
1257                 return;
1258
1259         ref.dev = dev;
1260         ref.dev_addr = dma_addr;
1261         bucket = get_hash_bucket(&ref, &flags);
1262
1263         list_for_each_entry(entry, &bucket->list, list) {
1264                 if (!exact_match(&ref, entry))
1265                         continue;
1266
1267                 /*
1268                  * The same physical address can be mapped multiple
1269                  * times. Without a hardware IOMMU this results in the
1270                  * same device addresses being put into the dma-debug
1271                  * hash multiple times too. This can result in false
1272                  * positives being reported. Therefore we implement a
1273                  * best-fit algorithm here which updates the first entry
1274                  * from the hash which fits the reference value and is
1275                  * not currently listed as being checked.
1276                  */
1277                 if (entry->map_err_type == MAP_ERR_NOT_CHECKED) {
1278                         entry->map_err_type = MAP_ERR_CHECKED;
1279                         break;
1280                 }
1281         }
1282
1283         put_hash_bucket(bucket, flags);
1284 }
1285 EXPORT_SYMBOL(debug_dma_mapping_error);
1286
1287 void debug_dma_unmap_page(struct device *dev, dma_addr_t addr,
1288                           size_t size, int direction)
1289 {
1290         struct dma_debug_entry ref = {
1291                 .type           = dma_debug_single,
1292                 .dev            = dev,
1293                 .dev_addr       = addr,
1294                 .size           = size,
1295                 .direction      = direction,
1296         };
1297
1298         if (unlikely(dma_debug_disabled()))
1299                 return;
1300         check_unmap(&ref);
1301 }
1302
1303 void debug_dma_map_sg(struct device *dev, struct scatterlist *sg,
1304                       int nents, int mapped_ents, int direction)
1305 {
1306         struct dma_debug_entry *entry;
1307         struct scatterlist *s;
1308         int i;
1309
1310         if (unlikely(dma_debug_disabled()))
1311                 return;
1312
1313         for_each_sg(sg, s, nents, i) {
1314                 check_for_stack(dev, sg_page(s), s->offset);
1315                 if (!PageHighMem(sg_page(s)))
1316                         check_for_illegal_area(dev, sg_virt(s), s->length);
1317         }
1318
1319         for_each_sg(sg, s, mapped_ents, i) {
1320                 entry = dma_entry_alloc();
1321                 if (!entry)
1322                         return;
1323
1324                 entry->type           = dma_debug_sg;
1325                 entry->dev            = dev;
1326                 entry->pfn            = page_to_pfn(sg_page(s));
1327                 entry->offset         = s->offset;
1328                 entry->size           = sg_dma_len(s);
1329                 entry->dev_addr       = sg_dma_address(s);
1330                 entry->direction      = direction;
1331                 entry->sg_call_ents   = nents;
1332                 entry->sg_mapped_ents = mapped_ents;
1333
1334                 check_sg_segment(dev, s);
1335
1336                 add_dma_entry(entry);
1337         }
1338 }
1339
1340 static int get_nr_mapped_entries(struct device *dev,
1341                                  struct dma_debug_entry *ref)
1342 {
1343         struct dma_debug_entry *entry;
1344         struct hash_bucket *bucket;
1345         unsigned long flags;
1346         int mapped_ents;
1347
1348         bucket       = get_hash_bucket(ref, &flags);
1349         entry        = bucket_find_exact(bucket, ref);
1350         mapped_ents  = 0;
1351
1352         if (entry)
1353                 mapped_ents = entry->sg_mapped_ents;
1354         put_hash_bucket(bucket, flags);
1355
1356         return mapped_ents;
1357 }
1358
1359 void debug_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
1360                         int nelems, int dir)
1361 {
1362         struct scatterlist *s;
1363         int mapped_ents = 0, i;
1364
1365         if (unlikely(dma_debug_disabled()))
1366                 return;
1367
1368         for_each_sg(sglist, s, nelems, i) {
1369
1370                 struct dma_debug_entry ref = {
1371                         .type           = dma_debug_sg,
1372                         .dev            = dev,
1373                         .pfn            = page_to_pfn(sg_page(s)),
1374                         .offset         = s->offset,
1375                         .dev_addr       = sg_dma_address(s),
1376                         .size           = sg_dma_len(s),
1377                         .direction      = dir,
1378                         .sg_call_ents   = nelems,
1379                 };
1380
1381                 if (mapped_ents && i >= mapped_ents)
1382                         break;
1383
1384                 if (!i)
1385                         mapped_ents = get_nr_mapped_entries(dev, &ref);
1386
1387                 check_unmap(&ref);
1388         }
1389 }
1390
1391 void debug_dma_alloc_coherent(struct device *dev, size_t size,
1392                               dma_addr_t dma_addr, void *virt)
1393 {
1394         struct dma_debug_entry *entry;
1395
1396         if (unlikely(dma_debug_disabled()))
1397                 return;
1398
1399         if (unlikely(virt == NULL))
1400                 return;
1401
1402         /* handle vmalloc and linear addresses */
1403         if (!is_vmalloc_addr(virt) && !virt_addr_valid(virt))
1404                 return;
1405
1406         entry = dma_entry_alloc();
1407         if (!entry)
1408                 return;
1409
1410         entry->type      = dma_debug_coherent;
1411         entry->dev       = dev;
1412         entry->offset    = offset_in_page(virt);
1413         entry->size      = size;
1414         entry->dev_addr  = dma_addr;
1415         entry->direction = DMA_BIDIRECTIONAL;
1416
1417         if (is_vmalloc_addr(virt))
1418                 entry->pfn = vmalloc_to_pfn(virt);
1419         else
1420                 entry->pfn = page_to_pfn(virt_to_page(virt));
1421
1422         add_dma_entry(entry);
1423 }
1424
1425 void debug_dma_free_coherent(struct device *dev, size_t size,
1426                          void *virt, dma_addr_t addr)
1427 {
1428         struct dma_debug_entry ref = {
1429                 .type           = dma_debug_coherent,
1430                 .dev            = dev,
1431                 .offset         = offset_in_page(virt),
1432                 .dev_addr       = addr,
1433                 .size           = size,
1434                 .direction      = DMA_BIDIRECTIONAL,
1435         };
1436
1437         /* handle vmalloc and linear addresses */
1438         if (!is_vmalloc_addr(virt) && !virt_addr_valid(virt))
1439                 return;
1440
1441         if (is_vmalloc_addr(virt))
1442                 ref.pfn = vmalloc_to_pfn(virt);
1443         else
1444                 ref.pfn = page_to_pfn(virt_to_page(virt));
1445
1446         if (unlikely(dma_debug_disabled()))
1447                 return;
1448
1449         check_unmap(&ref);
1450 }
1451
1452 void debug_dma_map_resource(struct device *dev, phys_addr_t addr, size_t size,
1453                             int direction, dma_addr_t dma_addr)
1454 {
1455         struct dma_debug_entry *entry;
1456
1457         if (unlikely(dma_debug_disabled()))
1458                 return;
1459
1460         entry = dma_entry_alloc();
1461         if (!entry)
1462                 return;
1463
1464         entry->type             = dma_debug_resource;
1465         entry->dev              = dev;
1466         entry->pfn              = PHYS_PFN(addr);
1467         entry->offset           = offset_in_page(addr);
1468         entry->size             = size;
1469         entry->dev_addr         = dma_addr;
1470         entry->direction        = direction;
1471         entry->map_err_type     = MAP_ERR_NOT_CHECKED;
1472
1473         add_dma_entry(entry);
1474 }
1475
1476 void debug_dma_unmap_resource(struct device *dev, dma_addr_t dma_addr,
1477                               size_t size, int direction)
1478 {
1479         struct dma_debug_entry ref = {
1480                 .type           = dma_debug_resource,
1481                 .dev            = dev,
1482                 .dev_addr       = dma_addr,
1483                 .size           = size,
1484                 .direction      = direction,
1485         };
1486
1487         if (unlikely(dma_debug_disabled()))
1488                 return;
1489
1490         check_unmap(&ref);
1491 }
1492
1493 void debug_dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_handle,
1494                                    size_t size, int direction)
1495 {
1496         struct dma_debug_entry ref;
1497
1498         if (unlikely(dma_debug_disabled()))
1499                 return;
1500
1501         ref.type         = dma_debug_single;
1502         ref.dev          = dev;
1503         ref.dev_addr     = dma_handle;
1504         ref.size         = size;
1505         ref.direction    = direction;
1506         ref.sg_call_ents = 0;
1507
1508         check_sync(dev, &ref, true);
1509 }
1510
1511 void debug_dma_sync_single_for_device(struct device *dev,
1512                                       dma_addr_t dma_handle, size_t size,
1513                                       int direction)
1514 {
1515         struct dma_debug_entry ref;
1516
1517         if (unlikely(dma_debug_disabled()))
1518                 return;
1519
1520         ref.type         = dma_debug_single;
1521         ref.dev          = dev;
1522         ref.dev_addr     = dma_handle;
1523         ref.size         = size;
1524         ref.direction    = direction;
1525         ref.sg_call_ents = 0;
1526
1527         check_sync(dev, &ref, false);
1528 }
1529
1530 void debug_dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
1531                                int nelems, int direction)
1532 {
1533         struct scatterlist *s;
1534         int mapped_ents = 0, i;
1535
1536         if (unlikely(dma_debug_disabled()))
1537                 return;
1538
1539         for_each_sg(sg, s, nelems, i) {
1540
1541                 struct dma_debug_entry ref = {
1542                         .type           = dma_debug_sg,
1543                         .dev            = dev,
1544                         .pfn            = page_to_pfn(sg_page(s)),
1545                         .offset         = s->offset,
1546                         .dev_addr       = sg_dma_address(s),
1547                         .size           = sg_dma_len(s),
1548                         .direction      = direction,
1549                         .sg_call_ents   = nelems,
1550                 };
1551
1552                 if (!i)
1553                         mapped_ents = get_nr_mapped_entries(dev, &ref);
1554
1555                 if (i >= mapped_ents)
1556                         break;
1557
1558                 check_sync(dev, &ref, true);
1559         }
1560 }
1561
1562 void debug_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
1563                                   int nelems, int direction)
1564 {
1565         struct scatterlist *s;
1566         int mapped_ents = 0, i;
1567
1568         if (unlikely(dma_debug_disabled()))
1569                 return;
1570
1571         for_each_sg(sg, s, nelems, i) {
1572
1573                 struct dma_debug_entry ref = {
1574                         .type           = dma_debug_sg,
1575                         .dev            = dev,
1576                         .pfn            = page_to_pfn(sg_page(s)),
1577                         .offset         = s->offset,
1578                         .dev_addr       = sg_dma_address(s),
1579                         .size           = sg_dma_len(s),
1580                         .direction      = direction,
1581                         .sg_call_ents   = nelems,
1582                 };
1583                 if (!i)
1584                         mapped_ents = get_nr_mapped_entries(dev, &ref);
1585
1586                 if (i >= mapped_ents)
1587                         break;
1588
1589                 check_sync(dev, &ref, false);
1590         }
1591 }
1592
1593 static int __init dma_debug_driver_setup(char *str)
1594 {
1595         int i;
1596
1597         for (i = 0; i < NAME_MAX_LEN - 1; ++i, ++str) {
1598                 current_driver_name[i] = *str;
1599                 if (*str == 0)
1600                         break;
1601         }
1602
1603         if (current_driver_name[0])
1604                 pr_info("enable driver filter for driver [%s]\n",
1605                         current_driver_name);
1606
1607
1608         return 1;
1609 }
1610 __setup("dma_debug_driver=", dma_debug_driver_setup);