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