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