lib/dma-debug.c

   1 /*
   2  * Copyright (C) 2008 Advanced Micro Devices, Inc.
   3  *
   4  * Author: Joerg Roedel <joerg.roedel@amd.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify it
   7  * under the terms of the GNU General Public License version 2 as published
   8  * by the Free Software Foundation.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  *
  15  * You should have received a copy of the GNU General Public License
  16  * along with this program; if not, write to the Free Software
  17  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
  18  */
  19
  20 #include <linux/scatterlist.h>
  21 #include <linux/dma-mapping.h>
  22 #include <linux/stacktrace.h>
  23 #include <linux/dma-debug.h>
  24 #include <linux/spinlock.h>
  25 #include <linux/debugfs.h>
  26 #include <linux/uaccess.h>
  27 #include <linux/device.h>
  28 #include <linux/types.h>
  29 #include <linux/sched.h>
  30 #include <linux/ctype.h>
  31 #include <linux/list.h>
  32 #include <linux/slab.h>
  33
  34 #include <asm/sections.h>
  35
  36 #define HASH_SIZE       1024ULL
  37 #define HASH_FN_SHIFT   13
  38 #define HASH_FN_MASK    (HASH_SIZE - 1)
  39
  40 enum {
  41         dma_debug_single,
  42         dma_debug_page,
  43         dma_debug_sg,
  44         dma_debug_coherent,
  45 };
  46
  47 #define DMA_DEBUG_STACKTRACE_ENTRIES 5
  48
  49 struct dma_debug_entry {
  50         struct list_head list;
  51         struct device    *dev;
  52         int              type;
  53         phys_addr_t      paddr;
  54         u64              dev_addr;
  55         u64              size;
  56         int              direction;
  57         int              sg_call_ents;
  58         int              sg_mapped_ents;
  59 #ifdef CONFIG_STACKTRACE
  60         struct           stack_trace stacktrace;
  61         unsigned long    st_entries[DMA_DEBUG_STACKTRACE_ENTRIES];
  62 #endif
  63 };
  64
  65 struct hash_bucket {
  66         struct list_head list;
  67         spinlock_t lock;
  68 } ____cacheline_aligned_in_smp;
  69
  70 /* Hash list to save the allocated dma addresses */
  71 static struct hash_bucket dma_entry_hash[HASH_SIZE];
  72 /* List of pre-allocated dma_debug_entry's */
  73 static LIST_HEAD(free_entries);
  74 /* Lock for the list above */
  75 static DEFINE_SPINLOCK(free_entries_lock);
  76
  77 /* Global disable flag - will be set in case of an error */
  78 static bool global_disable __read_mostly;
  79
  80 /* Global error count */
  81 static u32 error_count;
  82
  83 /* Global error show enable*/
  84 static u32 show_all_errors __read_mostly;
  85 /* Number of errors to show */
  86 static u32 show_num_errors = 1;
  87
  88 static u32 num_free_entries;
  89 static u32 min_free_entries;
  90 static u32 nr_total_entries;
  91
  92 /* number of preallocated entries requested by kernel cmdline */
  93 static u32 req_entries;
  94
  95 /* debugfs dentry's for the stuff above */
  96 static struct dentry *dma_debug_dent        __read_mostly;
  97 static struct dentry *global_disable_dent   __read_mostly;
  98 static struct dentry *error_count_dent      __read_mostly;
  99 static struct dentry *show_all_errors_dent  __read_mostly;
 100 static struct dentry *show_num_errors_dent  __read_mostly;
 101 static struct dentry *num_free_entries_dent __read_mostly;
 102 static struct dentry *min_free_entries_dent __read_mostly;
 103 static struct dentry *filter_dent           __read_mostly;
 104
 105 /* per-driver filter related state */
 106
 107 #define NAME_MAX_LEN    64
 108
 109 static char                  current_driver_name[NAME_MAX_LEN] __read_mostly;
 110 static struct device_driver *current_driver                    __read_mostly;
 111
 112 static DEFINE_RWLOCK(driver_name_lock);
 113
 114 static const char *type2name[4] = { "single", "page",
 115                                     "scather-gather", "coherent" };
 116
 117 static const char *dir2name[4] = { "DMA_BIDIRECTIONAL", "DMA_TO_DEVICE",
 118                                    "DMA_FROM_DEVICE", "DMA_NONE" };
 119
 120 /* little merge helper - remove it after the merge window */
 121 #ifndef BUS_NOTIFY_UNBOUND_DRIVER
 122 #define BUS_NOTIFY_UNBOUND_DRIVER 0x0005
 123 #endif
 124
 125 /*
 126  * The access to some variables in this macro is racy. We can't use atomic_t
 127  * here because all these variables are exported to debugfs. Some of them even
 128  * writeable. This is also the reason why a lock won't help much. But anyway,
 129  * the races are no big deal. Here is why:
 130  *
 131  *   error_count: the addition is racy, but the worst thing that can happen is
 132  *                that we don't count some errors
 133  *   show_num_errors: the subtraction is racy. Also no big deal because in
 134  *                    worst case this will result in one warning more in the
 135  *                    system log than the user configured. This variable is
 136  *                    writeable via debugfs.
 137  */
 138 static inline void dump_entry_trace(struct dma_debug_entry *entry)
 139 {
 140 #ifdef CONFIG_STACKTRACE
 141         if (entry) {
 142                 pr_warning("Mapped at:\n");
 143                 print_stack_trace(&entry->stacktrace, 0);
 144         }
 145 #endif
 146 }
 147
 148 static bool driver_filter(struct device *dev)
 149 {
 150         struct device_driver *drv;
 151         unsigned long flags;
 152         bool ret;
 153
 154         /* driver filter off */
 155         if (likely(!current_driver_name[0]))
 156                 return true;
 157
 158         /* driver filter on and initialized */
 159         if (current_driver && dev->driver == current_driver)
 160                 return true;
 161
 162         if (current_driver || !current_driver_name[0])
 163                 return false;
 164
 165         /* driver filter on but not yet initialized */
 166         drv = get_driver(dev->driver);
 167         if (!drv)
 168                 return false;
 169
 170         /* lock to protect against change of current_driver_name */
 171         read_lock_irqsave(&driver_name_lock, flags);
 172
 173         ret = false;
 174         if (drv->name &&
 175             strncmp(current_driver_name, drv->name, NAME_MAX_LEN - 1) == 0) {
 176                 current_driver = drv;
 177                 ret = true;
 178         }
 179
 180         read_unlock_irqrestore(&driver_name_lock, flags);
 181         put_driver(drv);
 182
 183         return ret;
 184 }
 185
 186 #define err_printk(dev, entry, format, arg...) do {             \
 187                 error_count += 1;                               \
 188                 if (driver_filter(dev) &&                       \
 189                     (show_all_errors || show_num_errors > 0)) { \
 190                         WARN(1, "%s %s: " format,               \
 191                              dev_driver_string(dev),            \
 192                              dev_name(dev) , ## arg);           \
 193                         dump_entry_trace(entry);                \
 194                 }                                               \
 195                 if (!show_all_errors && show_num_errors > 0)    \
 196                         show_num_errors -= 1;                   \
 197         } while (0);
 198
 199 /*
 200  * Hash related functions
 201  *
 202  * Every DMA-API request is saved into a struct dma_debug_entry. To
 203  * have quick access to these structs they are stored into a hash.
 204  */
 205 static int hash_fn(struct dma_debug_entry *entry)
 206 {
 207         /*
 208          * Hash function is based on the dma address.
 209          * We use bits 20-27 here as the index into the hash
 210          */
 211         return (entry->dev_addr >> HASH_FN_SHIFT) & HASH_FN_MASK;
 212 }
 213
 214 /*
 215  * Request exclusive access to a hash bucket for a given dma_debug_entry.
 216  */
 217 static struct hash_bucket *get_hash_bucket(struct dma_debug_entry *entry,
 218                                            unsigned long *flags)
 219 {
 220         int idx = hash_fn(entry);
 221         unsigned long __flags;
 222
 223         spin_lock_irqsave(&dma_entry_hash[idx].lock, __flags);
 224         *flags = __flags;
 225         return &dma_entry_hash[idx];
 226 }
 227
 228 /*
 229  * Give up exclusive access to the hash bucket
 230  */
 231 static void put_hash_bucket(struct hash_bucket *bucket,
 232                             unsigned long *flags)
 233 {
 234         unsigned long __flags = *flags;
 235
 236         spin_unlock_irqrestore(&bucket->lock, __flags);
 237 }
 238
 239 /*
 240  * Search a given entry in the hash bucket list
 241  */
 242 static struct dma_debug_entry *hash_bucket_find(struct hash_bucket *bucket,
 243                                                 struct dma_debug_entry *ref)
 244 {
 245         struct dma_debug_entry *entry, *ret = NULL;
 246         int matches = 0, match_lvl, last_lvl = 0;
 247
 248         list_for_each_entry(entry, &bucket->list, list) {
 249                 if ((entry->dev_addr != ref->dev_addr) ||
 250                     (entry->dev != ref->dev))
 251                         continue;
 252
 253                 /*
 254                  * Some drivers map the same physical address multiple
 255                  * times. Without a hardware IOMMU this results in the
 256                  * same device addresses being put into the dma-debug
 257                  * hash multiple times too. This can result in false
 258                  * positives being reported. Therfore we implement a
 259                  * best-fit algorithm here which returns the entry from
 260                  * the hash which fits best to the reference value
 261                  * instead of the first-fit.
 262                  */
 263                 matches += 1;
 264                 match_lvl = 0;
 265                 entry->size         == ref->size         ? ++match_lvl : 0;
 266                 entry->type         == ref->type         ? ++match_lvl : 0;
 267                 entry->direction    == ref->direction    ? ++match_lvl : 0;
 268                 entry->sg_call_ents == ref->sg_call_ents ? ++match_lvl : 0;
 269
 270                 if (match_lvl == 4) {
 271                         /* perfect-fit - return the result */
 272                         return entry;
 273                 } else if (match_lvl > last_lvl) {
 274                         /*
 275                          * We found an entry that fits better then the
 276                          * previous one
 277                          */
 278                         last_lvl = match_lvl;
 279                         ret      = entry;
 280                 }
 281         }
 282
 283         /*
 284          * If we have multiple matches but no perfect-fit, just return
 285          * NULL.
 286          */
 287         ret = (matches == 1) ? ret : NULL;
 288
 289         return ret;
 290 }
 291
 292 /*
 293  * Add an entry to a hash bucket
 294  */
 295 static void hash_bucket_add(struct hash_bucket *bucket,
 296                             struct dma_debug_entry *entry)
 297 {
 298         list_add_tail(&entry->list, &bucket->list);
 299 }
 300
 301 /*
 302  * Remove entry from a hash bucket list
 303  */
 304 static void hash_bucket_del(struct dma_debug_entry *entry)
 305 {
 306         list_del(&entry->list);
 307 }
 308
 309 /*
 310  * Dump mapping entries for debugging purposes
 311  */
 312 void debug_dma_dump_mappings(struct device *dev)
 313 {
 314         int idx;
 315
 316         for (idx = 0; idx < HASH_SIZE; idx++) {
 317                 struct hash_bucket *bucket = &dma_entry_hash[idx];
 318                 struct dma_debug_entry *entry;
 319                 unsigned long flags;
 320
 321                 spin_lock_irqsave(&bucket->lock, flags);
 322
 323                 list_for_each_entry(entry, &bucket->list, list) {
 324                         if (!dev || dev == entry->dev) {
 325                                 dev_info(entry->dev,
 326                                          "%s idx %d P=%Lx D=%Lx L=%Lx %s\n",
 327                                          type2name[entry->type], idx,
 328                                          (unsigned long long)entry->paddr,
 329                                          entry->dev_addr, entry->size,
 330                                          dir2name[entry->direction]);
 331                         }
 332                 }
 333
 334                 spin_unlock_irqrestore(&bucket->lock, flags);
 335         }
 336 }
 337 EXPORT_SYMBOL(debug_dma_dump_mappings);
 338
 339 /*
 340  * Wrapper function for adding an entry to the hash.
 341  * This function takes care of locking itself.
 342  */
 343 static void add_dma_entry(struct dma_debug_entry *entry)
 344 {
 345         struct hash_bucket *bucket;
 346         unsigned long flags;
 347
 348         bucket = get_hash_bucket(entry, &flags);
 349         hash_bucket_add(bucket, entry);
 350         put_hash_bucket(bucket, &flags);
 351 }
 352
 353 static struct dma_debug_entry *__dma_entry_alloc(void)
 354 {
 355         struct dma_debug_entry *entry;
 356
 357         entry = list_entry(free_entries.next, struct dma_debug_entry, list);
 358         list_del(&entry->list);
 359         memset(entry, 0, sizeof(*entry));
 360
 361         num_free_entries -= 1;
 362         if (num_free_entries < min_free_entries)
 363                 min_free_entries = num_free_entries;
 364
 365         return entry;
 366 }
 367
 368 /* struct dma_entry allocator
 369  *
 370  * The next two functions implement the allocator for
 371  * struct dma_debug_entries.
 372  */
 373 static struct dma_debug_entry *dma_entry_alloc(void)
 374 {
 375         struct dma_debug_entry *entry = NULL;
 376         unsigned long flags;
 377
 378         spin_lock_irqsave(&free_entries_lock, flags);
 379
 380         if (list_empty(&free_entries)) {
 381                 pr_err("DMA-API: debugging out of memory - disabling\n");
 382                 global_disable = true;
 383                 goto out;
 384         }
 385
 386         entry = __dma_entry_alloc();
 387
 388 #ifdef CONFIG_STACKTRACE
 389         entry->stacktrace.max_entries = DMA_DEBUG_STACKTRACE_ENTRIES;
 390         entry->stacktrace.entries = entry->st_entries;
 391         entry->stacktrace.skip = 2;
 392         save_stack_trace(&entry->stacktrace);
 393 #endif
 394
 395 out:
 396         spin_unlock_irqrestore(&free_entries_lock, flags);
 397
 398         return entry;
 399 }
 400
 401 static void dma_entry_free(struct dma_debug_entry *entry)
 402 {
 403         unsigned long flags;
 404
 405         /*
 406          * add to beginning of the list - this way the entries are
 407          * more likely cache hot when they are reallocated.
 408          */
 409         spin_lock_irqsave(&free_entries_lock, flags);
 410         list_add(&entry->list, &free_entries);
 411         num_free_entries += 1;
 412         spin_unlock_irqrestore(&free_entries_lock, flags);
 413 }
 414
 415 int dma_debug_resize_entries(u32 num_entries)
 416 {
 417         int i, delta, ret = 0;
 418         unsigned long flags;
 419         struct dma_debug_entry *entry;
 420         LIST_HEAD(tmp);
 421
 422         spin_lock_irqsave(&free_entries_lock, flags);
 423
 424         if (nr_total_entries < num_entries) {
 425                 delta = num_entries - nr_total_entries;
 426
 427                 spin_unlock_irqrestore(&free_entries_lock, flags);
 428
 429                 for (i = 0; i < delta; i++) {
 430                         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 431                         if (!entry)
 432                                 break;
 433
 434                         list_add_tail(&entry->list, &tmp);
 435                 }
 436
 437                 spin_lock_irqsave(&free_entries_lock, flags);
 438
 439                 list_splice(&tmp, &free_entries);
 440                 nr_total_entries += i;
 441                 num_free_entries += i;
 442         } else {
 443                 delta = nr_total_entries - num_entries;
 444
 445                 for (i = 0; i < delta && !list_empty(&free_entries); i++) {
 446                         entry = __dma_entry_alloc();
 447                         kfree(entry);
 448                 }
 449
 450                 nr_total_entries -= i;
 451         }
 452
 453         if (nr_total_entries != num_entries)
 454                 ret = 1;
 455
 456         spin_unlock_irqrestore(&free_entries_lock, flags);
 457
 458         return ret;
 459 }
 460 EXPORT_SYMBOL(dma_debug_resize_entries);
 461
 462 /*
 463  * DMA-API debugging init code
 464  *
 465  * The init code does two things:
 466  *   1. Initialize core data structures
 467  *   2. Preallocate a given number of dma_debug_entry structs
 468  */
 469
 470 static int prealloc_memory(u32 num_entries)
 471 {
 472         struct dma_debug_entry *entry, *next_entry;
 473         int i;
 474
 475         for (i = 0; i < num_entries; ++i) {
 476                 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 477                 if (!entry)
 478                         goto out_err;
 479
 480                 list_add_tail(&entry->list, &free_entries);
 481         }
 482
 483         num_free_entries = num_entries;
 484         min_free_entries = num_entries;
 485
 486         pr_info("DMA-API: preallocated %d debug entries\n", num_entries);
 487
 488         return 0;
 489
 490 out_err:
 491
 492         list_for_each_entry_safe(entry, next_entry, &free_entries, list) {
 493                 list_del(&entry->list);
 494                 kfree(entry);
 495         }
 496
 497         return -ENOMEM;
 498 }
 499
 500 static ssize_t filter_read(struct file *file, char __user *user_buf,
 501                            size_t count, loff_t *ppos)
 502 {
 503         char buf[NAME_MAX_LEN + 1];
 504         unsigned long flags;
 505         int len;
 506
 507         if (!current_driver_name[0])
 508                 return 0;
 509
 510         /*
 511          * We can't copy to userspace directly because current_driver_name can
 512          * only be read under the driver_name_lock with irqs disabled. So
 513          * create a temporary copy first.
 514          */
 515         read_lock_irqsave(&driver_name_lock, flags);
 516         len = scnprintf(buf, NAME_MAX_LEN + 1, "%s\n", current_driver_name);
 517         read_unlock_irqrestore(&driver_name_lock, flags);
 518
 519         return simple_read_from_buffer(user_buf, count, ppos, buf, len);
 520 }
 521
 522 static ssize_t filter_write(struct file *file, const char __user *userbuf,
 523                             size_t count, loff_t *ppos)
 524 {
 525         char buf[NAME_MAX_LEN];
 526         unsigned long flags;
 527         size_t len;
 528         int i;
 529
 530         /*
 531          * We can't copy from userspace directly. Access to
 532          * current_driver_name is protected with a write_lock with irqs
 533          * disabled. Since copy_from_user can fault and may sleep we
 534          * need to copy to temporary buffer first
 535          */
 536         len = min(count, (size_t)(NAME_MAX_LEN - 1));
 537         if (copy_from_user(buf, userbuf, len))
 538                 return -EFAULT;
 539
 540         buf[len] = 0;
 541
 542         write_lock_irqsave(&driver_name_lock, flags);
 543
 544         /*
 545          * Now handle the string we got from userspace very carefully.
 546          * The rules are:
 547          *         - only use the first token we got
 548          *         - token delimiter is everything looking like a space
 549          *           character (' ', '\n', '\t' ...)
 550          *
 551          */
 552         if (!isalnum(buf[0])) {
 553                 /*
 554                  * If the first character userspace gave us is not
 555                  * alphanumerical then assume the filter should be
 556                  * switched off.
 557                  */
 558                 if (current_driver_name[0])
 559                         pr_info("DMA-API: switching off dma-debug driver filter\n");
 560                 current_driver_name[0] = 0;
 561                 current_driver = NULL;
 562                 goto out_unlock;
 563         }
 564
 565         /*
 566          * Now parse out the first token and use it as the name for the
 567          * driver to filter for.
 568          */
 569         for (i = 0; i < NAME_MAX_LEN; ++i) {
 570                 current_driver_name[i] = buf[i];
 571                 if (isspace(buf[i]) || buf[i] == ' ' || buf[i] == 0)
 572                         break;
 573         }
 574         current_driver_name[i] = 0;
 575         current_driver = NULL;
 576
 577         pr_info("DMA-API: enable driver filter for driver [%s]\n",
 578                 current_driver_name);
 579
 580 out_unlock:
 581         write_unlock_irqrestore(&driver_name_lock, flags);
 582
 583         return count;
 584 }
 585
 586 const struct file_operations filter_fops = {
 587         .read  = filter_read,
 588         .write = filter_write,
 589 };
 590
 591 static int dma_debug_fs_init(void)
 592 {
 593         dma_debug_dent = debugfs_create_dir("dma-api", NULL);
 594         if (!dma_debug_dent) {
 595                 pr_err("DMA-API: can not create debugfs directory\n");
 596                 return -ENOMEM;
 597         }
 598
 599         global_disable_dent = debugfs_create_bool("disabled", 0444,
 600                         dma_debug_dent,
 601                         (u32 *)&global_disable);
 602         if (!global_disable_dent)
 603                 goto out_err;
 604
 605         error_count_dent = debugfs_create_u32("error_count", 0444,
 606                         dma_debug_dent, &error_count);
 607         if (!error_count_dent)
 608                 goto out_err;
 609
 610         show_all_errors_dent = debugfs_create_u32("all_errors", 0644,
 611                         dma_debug_dent,
 612                         &show_all_errors);
 613         if (!show_all_errors_dent)
 614                 goto out_err;
 615
 616         show_num_errors_dent = debugfs_create_u32("num_errors", 0644,
 617                         dma_debug_dent,
 618                         &show_num_errors);
 619         if (!show_num_errors_dent)
 620                 goto out_err;
 621
 622         num_free_entries_dent = debugfs_create_u32("num_free_entries", 0444,
 623                         dma_debug_dent,
 624                         &num_free_entries);
 625         if (!num_free_entries_dent)
 626                 goto out_err;
 627
 628         min_free_entries_dent = debugfs_create_u32("min_free_entries", 0444,
 629                         dma_debug_dent,
 630                         &min_free_entries);
 631         if (!min_free_entries_dent)
 632                 goto out_err;
 633
 634         filter_dent = debugfs_create_file("driver_filter", 0644,
 635                                           dma_debug_dent, NULL, &filter_fops);
 636         if (!filter_dent)
 637                 goto out_err;
 638
 639         return 0;
 640
 641 out_err:
 642         debugfs_remove_recursive(dma_debug_dent);
 643
 644         return -ENOMEM;
 645 }
 646
 647 static int device_dma_allocations(struct device *dev)
 648 {
 649         struct dma_debug_entry *entry;
 650         unsigned long flags;
 651         int count = 0, i;
 652
 653         local_irq_save(flags);
 654
 655         for (i = 0; i < HASH_SIZE; ++i) {
 656                 spin_lock(&dma_entry_hash[i].lock);
 657                 list_for_each_entry(entry, &dma_entry_hash[i].list, list) {
 658                         if (entry->dev == dev)
 659                                 count += 1;
 660                 }
 661                 spin_unlock(&dma_entry_hash[i].lock);
 662         }
 663
 664         local_irq_restore(flags);
 665
 666         return count;
 667 }
 668
 669 static int dma_debug_device_change(struct notifier_block *nb,
 670                                     unsigned long action, void *data)
 671 {
 672         struct device *dev = data;
 673         int count;
 674
 675
 676         switch (action) {
 677         case BUS_NOTIFY_UNBOUND_DRIVER:
 678                 count = device_dma_allocations(dev);
 679                 if (count == 0)
 680                         break;
 681                 err_printk(dev, NULL, "DMA-API: device driver has pending "
 682                                 "DMA allocations while released from device "
 683                                 "[count=%d]\n", count);
 684                 break;
 685         default:
 686                 break;
 687         }
 688
 689         return 0;
 690 }
 691
 692 void dma_debug_add_bus(struct bus_type *bus)
 693 {
 694         struct notifier_block *nb;
 695
 696         nb = kzalloc(sizeof(struct notifier_block), GFP_KERNEL);
 697         if (nb == NULL) {
 698                 pr_err("dma_debug_add_bus: out of memory\n");
 699                 return;
 700         }
 701
 702         nb->notifier_call = dma_debug_device_change;
 703
 704         bus_register_notifier(bus, nb);
 705 }
 706
 707 /*
 708  * Let the architectures decide how many entries should be preallocated.
 709  */
 710 void dma_debug_init(u32 num_entries)
 711 {
 712         int i;
 713
 714         if (global_disable)
 715                 return;
 716
 717         for (i = 0; i < HASH_SIZE; ++i) {
 718                 INIT_LIST_HEAD(&dma_entry_hash[i].list);
 719                 dma_entry_hash[i].lock = SPIN_LOCK_UNLOCKED;
 720         }
 721
 722         if (dma_debug_fs_init() != 0) {
 723                 pr_err("DMA-API: error creating debugfs entries - disabling\n");
 724                 global_disable = true;
 725
 726                 return;
 727         }
 728
 729         if (req_entries)
 730                 num_entries = req_entries;
 731
 732         if (prealloc_memory(num_entries) != 0) {
 733                 pr_err("DMA-API: debugging out of memory error - disabled\n");
 734                 global_disable = true;
 735
 736                 return;
 737         }
 738
 739         nr_total_entries = num_free_entries;
 740
 741         pr_info("DMA-API: debugging enabled by kernel config\n");
 742 }
 743
 744 static __init int dma_debug_cmdline(char *str)
 745 {
 746         if (!str)
 747                 return -EINVAL;
 748
 749         if (strncmp(str, "off", 3) == 0) {
 750                 pr_info("DMA-API: debugging disabled on kernel command line\n");
 751                 global_disable = true;
 752         }
 753
 754         return 0;
 755 }
 756
 757 static __init int dma_debug_entries_cmdline(char *str)
 758 {
 759         int res;
 760
 761         if (!str)
 762                 return -EINVAL;
 763
 764         res = get_option(&str, &req_entries);
 765
 766         if (!res)
 767                 req_entries = 0;
 768
 769         return 0;
 770 }
 771
 772 __setup("dma_debug=", dma_debug_cmdline);
 773 __setup("dma_debug_entries=", dma_debug_entries_cmdline);
 774
 775 static void check_unmap(struct dma_debug_entry *ref)
 776 {
 777         struct dma_debug_entry *entry;
 778         struct hash_bucket *bucket;
 779         unsigned long flags;
 780
 781         if (dma_mapping_error(ref->dev, ref->dev_addr)) {
 782                 err_printk(ref->dev, NULL, "DMA-API: device driver tries "
 783                            "to free an invalid DMA memory address\n");
 784                 return;
 785         }
 786
 787         bucket = get_hash_bucket(ref, &flags);
 788         entry = hash_bucket_find(bucket, ref);
 789
 790         if (!entry) {
 791                 err_printk(ref->dev, NULL, "DMA-API: device driver tries "
 792                            "to free DMA memory it has not allocated "
 793                            "[device address=0x%016llx] [size=%llu bytes]\n",
 794                            ref->dev_addr, ref->size);
 795                 goto out;
 796         }
 797
 798         if (ref->size != entry->size) {
 799                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
 800                            "DMA memory with different size "
 801                            "[device address=0x%016llx] [map size=%llu bytes] "
 802                            "[unmap size=%llu bytes]\n",
 803                            ref->dev_addr, entry->size, ref->size);
 804         }
 805
 806         if (ref->type != entry->type) {
 807                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
 808                            "DMA memory with wrong function "
 809                            "[device address=0x%016llx] [size=%llu bytes] "
 810                            "[mapped as %s] [unmapped as %s]\n",
 811                            ref->dev_addr, ref->size,
 812                            type2name[entry->type], type2name[ref->type]);
 813         } else if ((entry->type == dma_debug_coherent) &&
 814                    (ref->paddr != entry->paddr)) {
 815                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
 816                            "DMA memory with different CPU address "
 817                            "[device address=0x%016llx] [size=%llu bytes] "
 818                            "[cpu alloc address=%p] [cpu free address=%p]",
 819                            ref->dev_addr, ref->size,
 820                            (void *)entry->paddr, (void *)ref->paddr);
 821         }
 822
 823         if (ref->sg_call_ents && ref->type == dma_debug_sg &&
 824             ref->sg_call_ents != entry->sg_call_ents) {
 825                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
 826                            "DMA sg list with different entry count "
 827                            "[map count=%d] [unmap count=%d]\n",
 828                            entry->sg_call_ents, ref->sg_call_ents);
 829         }
 830
 831         /*
 832          * This may be no bug in reality - but most implementations of the
 833          * DMA API don't handle this properly, so check for it here
 834          */
 835         if (ref->direction != entry->direction) {
 836                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
 837                            "DMA memory with different direction "
 838                            "[device address=0x%016llx] [size=%llu bytes] "
 839                            "[mapped with %s] [unmapped with %s]\n",
 840                            ref->dev_addr, ref->size,
 841                            dir2name[entry->direction],
 842                            dir2name[ref->direction]);
 843         }
 844
 845         hash_bucket_del(entry);
 846         dma_entry_free(entry);
 847
 848 out:
 849         put_hash_bucket(bucket, &flags);
 850 }
 851
 852 static void check_for_stack(struct device *dev, void *addr)
 853 {
 854         if (object_is_on_stack(addr))
 855                 err_printk(dev, NULL, "DMA-API: device driver maps memory from"
 856                                 "stack [addr=%p]\n", addr);
 857 }
 858
 859 static inline bool overlap(void *addr, u64 size, void *start, void *end)
 860 {
 861         void *addr2 = (char *)addr + size;
 862
 863         return ((addr >= start && addr < end) ||
 864                 (addr2 >= start && addr2 < end) ||
 865                 ((addr < start) && (addr2 >= end)));
 866 }
 867
 868 static void check_for_illegal_area(struct device *dev, void *addr, u64 size)
 869 {
 870         if (overlap(addr, size, _text, _etext) ||
 871             overlap(addr, size, __start_rodata, __end_rodata))
 872                 err_printk(dev, NULL, "DMA-API: device driver maps "
 873                                 "memory from kernel text or rodata "
 874                                 "[addr=%p] [size=%llu]\n", addr, size);
 875 }
 876
 877 static void check_sync(struct device *dev,
 878                        struct dma_debug_entry *ref,
 879                        bool to_cpu)
 880 {
 881         struct dma_debug_entry *entry;
 882         struct hash_bucket *bucket;
 883         unsigned long flags;
 884
 885         bucket = get_hash_bucket(ref, &flags);
 886
 887         entry = hash_bucket_find(bucket, ref);
 888
 889         if (!entry) {
 890                 err_printk(dev, NULL, "DMA-API: device driver tries "
 891                                 "to sync DMA memory it has not allocated "
 892                                 "[device address=0x%016llx] [size=%llu bytes]\n",
 893                                 (unsigned long long)ref->dev_addr, ref->size);
 894                 goto out;
 895         }
 896
 897         if (ref->size > entry->size) {
 898                 err_printk(dev, entry, "DMA-API: device driver syncs"
 899                                 " DMA memory outside allocated range "
 900                                 "[device address=0x%016llx] "
 901                                 "[allocation size=%llu bytes] "
 902                                 "[sync offset+size=%llu]\n",
 903                                 entry->dev_addr, entry->size,
 904                                 ref->size);
 905         }
 906
 907         if (ref->direction != entry->direction) {
 908                 err_printk(dev, entry, "DMA-API: device driver syncs "
 909                                 "DMA memory with different direction "
 910                                 "[device address=0x%016llx] [size=%llu bytes] "
 911                                 "[mapped with %s] [synced with %s]\n",
 912                                 (unsigned long long)ref->dev_addr, entry->size,
 913                                 dir2name[entry->direction],
 914                                 dir2name[ref->direction]);
 915         }
 916
 917         if (entry->direction == DMA_BIDIRECTIONAL)
 918                 goto out;
 919
 920         if (to_cpu && !(entry->direction == DMA_FROM_DEVICE) &&
 921                       !(ref->direction == DMA_TO_DEVICE))
 922                 err_printk(dev, entry, "DMA-API: device driver syncs "
 923                                 "device read-only DMA memory for cpu "
 924                                 "[device address=0x%016llx] [size=%llu bytes] "
 925                                 "[mapped with %s] [synced with %s]\n",
 926                                 (unsigned long long)ref->dev_addr, entry->size,
 927                                 dir2name[entry->direction],
 928                                 dir2name[ref->direction]);
 929
 930         if (!to_cpu && !(entry->direction == DMA_TO_DEVICE) &&
 931                        !(ref->direction == DMA_FROM_DEVICE))
 932                 err_printk(dev, entry, "DMA-API: device driver syncs "
 933                                 "device write-only DMA memory to device "
 934                                 "[device address=0x%016llx] [size=%llu bytes] "
 935                                 "[mapped with %s] [synced with %s]\n",
 936                                 (unsigned long long)ref->dev_addr, entry->size,
 937                                 dir2name[entry->direction],
 938                                 dir2name[ref->direction]);
 939
 940 out:
 941         put_hash_bucket(bucket, &flags);
 942
 943 }
 944
 945 void debug_dma_map_page(struct device *dev, struct page *page, size_t offset,
 946                         size_t size, int direction, dma_addr_t dma_addr,
 947                         bool map_single)
 948 {
 949         struct dma_debug_entry *entry;
 950
 951         if (unlikely(global_disable))
 952                 return;
 953
 954         if (unlikely(dma_mapping_error(dev, dma_addr)))
 955                 return;
 956
 957         entry = dma_entry_alloc();
 958         if (!entry)
 959                 return;
 960
 961         entry->dev       = dev;
 962         entry->type      = dma_debug_page;
 963         entry->paddr     = page_to_phys(page) + offset;
 964         entry->dev_addr  = dma_addr;
 965         entry->size      = size;
 966         entry->direction = direction;
 967
 968         if (map_single)
 969                 entry->type = dma_debug_single;
 970
 971         if (!PageHighMem(page)) {
 972                 void *addr = ((char *)page_address(page)) + offset;
 973                 check_for_stack(dev, addr);
 974                 check_for_illegal_area(dev, addr, size);
 975         }
 976
 977         add_dma_entry(entry);
 978 }
 979 EXPORT_SYMBOL(debug_dma_map_page);
 980
 981 void debug_dma_unmap_page(struct device *dev, dma_addr_t addr,
 982                           size_t size, int direction, bool map_single)
 983 {
 984         struct dma_debug_entry ref = {
 985                 .type           = dma_debug_page,
 986                 .dev            = dev,
 987                 .dev_addr       = addr,
 988                 .size           = size,
 989                 .direction      = direction,
 990         };
 991
 992         if (unlikely(global_disable))
 993                 return;
 994
 995         if (map_single)
 996                 ref.type = dma_debug_single;
 997
 998         check_unmap(&ref);
 999 }
1000 EXPORT_SYMBOL(debug_dma_unmap_page);
1001
1002 void debug_dma_map_sg(struct device *dev, struct scatterlist *sg,
1003                       int nents, int mapped_ents, int direction)
1004 {
1005         struct dma_debug_entry *entry;
1006         struct scatterlist *s;
1007         int i;
1008
1009         if (unlikely(global_disable))
1010                 return;
1011
1012         for_each_sg(sg, s, mapped_ents, i) {
1013                 entry = dma_entry_alloc();
1014                 if (!entry)
1015                         return;
1016
1017                 entry->type           = dma_debug_sg;
1018                 entry->dev            = dev;
1019                 entry->paddr          = sg_phys(s);
1020                 entry->size           = sg_dma_len(s);
1021                 entry->dev_addr       = sg_dma_address(s);
1022                 entry->direction      = direction;
1023                 entry->sg_call_ents   = nents;
1024                 entry->sg_mapped_ents = mapped_ents;
1025
1026                 if (!PageHighMem(sg_page(s))) {
1027                         check_for_stack(dev, sg_virt(s));
1028                         check_for_illegal_area(dev, sg_virt(s), sg_dma_len(s));
1029                 }
1030
1031                 add_dma_entry(entry);
1032         }
1033 }
1034 EXPORT_SYMBOL(debug_dma_map_sg);
1035
1036 static int get_nr_mapped_entries(struct device *dev,
1037                                  struct dma_debug_entry *ref)
1038 {
1039         struct dma_debug_entry *entry;
1040         struct hash_bucket *bucket;
1041         unsigned long flags;
1042         int mapped_ents;
1043
1044         bucket       = get_hash_bucket(ref, &flags);
1045         entry        = hash_bucket_find(bucket, ref);
1046         mapped_ents  = 0;
1047
1048         if (entry)
1049                 mapped_ents = entry->sg_mapped_ents;
1050         put_hash_bucket(bucket, &flags);
1051
1052         return mapped_ents;
1053 }
1054
1055 void debug_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
1056                         int nelems, int dir)
1057 {
1058         struct scatterlist *s;
1059         int mapped_ents = 0, i;
1060
1061         if (unlikely(global_disable))
1062                 return;
1063
1064         for_each_sg(sglist, s, nelems, i) {
1065
1066                 struct dma_debug_entry ref = {
1067                         .type           = dma_debug_sg,
1068                         .dev            = dev,
1069                         .paddr          = sg_phys(s),
1070                         .dev_addr       = sg_dma_address(s),
1071                         .size           = sg_dma_len(s),
1072                         .direction      = dir,
1073                         .sg_call_ents   = nelems,
1074                 };
1075
1076                 if (mapped_ents && i >= mapped_ents)
1077                         break;
1078
1079                 if (!i)
1080                         mapped_ents = get_nr_mapped_entries(dev, &ref);
1081
1082                 check_unmap(&ref);
1083         }
1084 }
1085 EXPORT_SYMBOL(debug_dma_unmap_sg);
1086
1087 void debug_dma_alloc_coherent(struct device *dev, size_t size,
1088                               dma_addr_t dma_addr, void *virt)
1089 {
1090         struct dma_debug_entry *entry;
1091
1092         if (unlikely(global_disable))
1093                 return;
1094
1095         if (unlikely(virt == NULL))
1096                 return;
1097
1098         entry = dma_entry_alloc();
1099         if (!entry)
1100                 return;
1101
1102         entry->type      = dma_debug_coherent;
1103         entry->dev       = dev;
1104         entry->paddr     = virt_to_phys(virt);
1105         entry->size      = size;
1106         entry->dev_addr  = dma_addr;
1107         entry->direction = DMA_BIDIRECTIONAL;
1108
1109         add_dma_entry(entry);
1110 }
1111 EXPORT_SYMBOL(debug_dma_alloc_coherent);
1112
1113 void debug_dma_free_coherent(struct device *dev, size_t size,
1114                          void *virt, dma_addr_t addr)
1115 {
1116         struct dma_debug_entry ref = {
1117                 .type           = dma_debug_coherent,
1118                 .dev            = dev,
1119                 .paddr          = virt_to_phys(virt),
1120                 .dev_addr       = addr,
1121                 .size           = size,
1122                 .direction      = DMA_BIDIRECTIONAL,
1123         };
1124
1125         if (unlikely(global_disable))
1126                 return;
1127
1128         check_unmap(&ref);
1129 }
1130 EXPORT_SYMBOL(debug_dma_free_coherent);
1131
1132 void debug_dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_handle,
1133                                    size_t size, int direction)
1134 {
1135         struct dma_debug_entry ref;
1136
1137         if (unlikely(global_disable))
1138                 return;
1139
1140         ref.type         = dma_debug_single;
1141         ref.dev          = dev;
1142         ref.dev_addr     = dma_handle;
1143         ref.size         = size;
1144         ref.direction    = direction;
1145         ref.sg_call_ents = 0;
1146
1147         check_sync(dev, &ref, true);
1148 }
1149 EXPORT_SYMBOL(debug_dma_sync_single_for_cpu);
1150
1151 void debug_dma_sync_single_for_device(struct device *dev,
1152                                       dma_addr_t dma_handle, size_t size,
1153                                       int direction)
1154 {
1155         struct dma_debug_entry ref;
1156
1157         if (unlikely(global_disable))
1158                 return;
1159
1160         ref.type         = dma_debug_single;
1161         ref.dev          = dev;
1162         ref.dev_addr     = dma_handle;
1163         ref.size         = size;
1164         ref.direction    = direction;
1165         ref.sg_call_ents = 0;
1166
1167         check_sync(dev, &ref, false);
1168 }
1169 EXPORT_SYMBOL(debug_dma_sync_single_for_device);
1170
1171 void debug_dma_sync_single_range_for_cpu(struct device *dev,
1172                                          dma_addr_t dma_handle,
1173                                          unsigned long offset, size_t size,
1174                                          int direction)
1175 {
1176         struct dma_debug_entry ref;
1177
1178         if (unlikely(global_disable))
1179                 return;
1180
1181         ref.type         = dma_debug_single;
1182         ref.dev          = dev;
1183         ref.dev_addr     = dma_handle;
1184         ref.size         = offset + size;
1185         ref.direction    = direction;
1186         ref.sg_call_ents = 0;
1187
1188         check_sync(dev, &ref, true);
1189 }
1190 EXPORT_SYMBOL(debug_dma_sync_single_range_for_cpu);
1191
1192 void debug_dma_sync_single_range_for_device(struct device *dev,
1193                                             dma_addr_t dma_handle,
1194                                             unsigned long offset,
1195                                             size_t size, int direction)
1196 {
1197         struct dma_debug_entry ref;
1198
1199         if (unlikely(global_disable))
1200                 return;
1201
1202         ref.type         = dma_debug_single;
1203         ref.dev          = dev;
1204         ref.dev_addr     = dma_handle;
1205         ref.size         = offset + size;
1206         ref.direction    = direction;
1207         ref.sg_call_ents = 0;
1208
1209         check_sync(dev, &ref, false);
1210 }
1211 EXPORT_SYMBOL(debug_dma_sync_single_range_for_device);
1212
1213 void debug_dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
1214                                int nelems, int direction)
1215 {
1216         struct scatterlist *s;
1217         int mapped_ents = 0, i;
1218
1219         if (unlikely(global_disable))
1220                 return;
1221
1222         for_each_sg(sg, s, nelems, i) {
1223
1224                 struct dma_debug_entry ref = {
1225                         .type           = dma_debug_sg,
1226                         .dev            = dev,
1227                         .paddr          = sg_phys(s),
1228                         .dev_addr       = sg_dma_address(s),
1229                         .size           = sg_dma_len(s),
1230                         .direction      = direction,
1231                         .sg_call_ents   = nelems,
1232                 };
1233
1234                 if (!i)
1235                         mapped_ents = get_nr_mapped_entries(dev, &ref);
1236
1237                 if (i >= mapped_ents)
1238                         break;
1239
1240                 check_sync(dev, &ref, true);
1241         }
1242 }
1243 EXPORT_SYMBOL(debug_dma_sync_sg_for_cpu);
1244
1245 void debug_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
1246                                   int nelems, int direction)
1247 {
1248         struct scatterlist *s;
1249         int mapped_ents = 0, i;
1250
1251         if (unlikely(global_disable))
1252                 return;
1253
1254         for_each_sg(sg, s, nelems, i) {
1255
1256                 struct dma_debug_entry ref = {
1257                         .type           = dma_debug_sg,
1258                         .dev            = dev,
1259                         .paddr          = sg_phys(s),
1260                         .dev_addr       = sg_dma_address(s),
1261                         .size           = sg_dma_len(s),
1262                         .direction      = direction,
1263                         .sg_call_ents   = nelems,
1264                 };
1265                 if (!i)
1266                         mapped_ents = get_nr_mapped_entries(dev, &ref);
1267
1268                 if (i >= mapped_ents)
1269                         break;
1270
1271                 check_sync(dev, &ref, false);
1272         }
1273 }
1274 EXPORT_SYMBOL(debug_dma_sync_sg_for_device);
1275
1276 static int __init dma_debug_driver_setup(char *str)
1277 {
1278         int i;
1279
1280         for (i = 0; i < NAME_MAX_LEN - 1; ++i, ++str) {
1281                 current_driver_name[i] = *str;
1282                 if (*str == 0)
1283                         break;
1284         }
1285
1286         if (current_driver_name[0])
1287                 pr_info("DMA-API: enable driver filter for driver [%s]\n",
1288                         current_driver_name);
1289
1290
1291         return 1;
1292 }
1293 __setup("dma_debug_driver=", dma_debug_driver_setup);