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