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