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   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                 printk(KERN_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         /* driver filter off */
 151         if (likely(!current_driver_name[0]))
 152                 return true;
 153
 154         /* driver filter on and initialized */
 155         if (current_driver && dev->driver == current_driver)
 156                 return true;
 157
 158         /* driver filter on but not yet initialized */
 159         if (!current_driver && current_driver_name[0]) {
 160                 struct device_driver *drv = get_driver(dev->driver);
 161                 unsigned long flags;
 162                 bool ret = false;
 163
 164                 if (!drv)
 165                         return false;
 166
 167                 /* lock to protect against change of current_driver_name */
 168                 read_lock_irqsave(&driver_name_lock, flags);
 169
 170                 if (drv->name &&
 171                     strncmp(current_driver_name, drv->name,
 172                             NAME_MAX_LEN-1) == 0) {
 173                         current_driver = drv;
 174                         ret = true;
 175                 }
 176
 177                 read_unlock_irqrestore(&driver_name_lock, flags);
 178                 put_driver(drv);
 179
 180                 return ret;
 181         }
 182
 183         return false;
 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 : match_lvl;
 266                 entry->type      == ref->type      ? ++match_lvl : match_lvl;
 267                 entry->direction == ref->direction ? ++match_lvl : match_lvl;
 268
 269                 if (match_lvl == 3) {
 270                         /* perfect-fit - return the result */
 271                         return entry;
 272                 } else if (match_lvl > last_lvl) {
 273                         /*
 274                          * We found an entry that fits better then the
 275                          * previous one
 276                          */
 277                         last_lvl = match_lvl;
 278                         ret      = entry;
 279                 }
 280         }
 281
 282         /*
 283          * If we have multiple matches but no perfect-fit, just return
 284          * NULL.
 285          */
 286         ret = (matches == 1) ? ret : NULL;
 287
 288         return ret;
 289 }
 290
 291 /*
 292  * Add an entry to a hash bucket
 293  */
 294 static void hash_bucket_add(struct hash_bucket *bucket,
 295                             struct dma_debug_entry *entry)
 296 {
 297         list_add_tail(&entry->list, &bucket->list);
 298 }
 299
 300 /*
 301  * Remove entry from a hash bucket list
 302  */
 303 static void hash_bucket_del(struct dma_debug_entry *entry)
 304 {
 305         list_del(&entry->list);
 306 }
 307
 308 /*
 309  * Dump mapping entries for debugging purposes
 310  */
 311 void debug_dma_dump_mappings(struct device *dev)
 312 {
 313         int idx;
 314
 315         for (idx = 0; idx < HASH_SIZE; idx++) {
 316                 struct hash_bucket *bucket = &dma_entry_hash[idx];
 317                 struct dma_debug_entry *entry;
 318                 unsigned long flags;
 319
 320                 spin_lock_irqsave(&bucket->lock, flags);
 321
 322                 list_for_each_entry(entry, &bucket->list, list) {
 323                         if (!dev || dev == entry->dev) {
 324                                 dev_info(entry->dev,
 325                                          "%s idx %d P=%Lx D=%Lx L=%Lx %s\n",
 326                                          type2name[entry->type], idx,
 327                                          (unsigned long long)entry->paddr,
 328                                          entry->dev_addr, entry->size,
 329                                          dir2name[entry->direction]);
 330                         }
 331                 }
 332
 333                 spin_unlock_irqrestore(&bucket->lock, flags);
 334         }
 335 }
 336 EXPORT_SYMBOL(debug_dma_dump_mappings);
 337
 338 /*
 339  * Wrapper function for adding an entry to the hash.
 340  * This function takes care of locking itself.
 341  */
 342 static void add_dma_entry(struct dma_debug_entry *entry)
 343 {
 344         struct hash_bucket *bucket;
 345         unsigned long flags;
 346
 347         bucket = get_hash_bucket(entry, &flags);
 348         hash_bucket_add(bucket, entry);
 349         put_hash_bucket(bucket, &flags);
 350 }
 351
 352 static struct dma_debug_entry *__dma_entry_alloc(void)
 353 {
 354         struct dma_debug_entry *entry;
 355
 356         entry = list_entry(free_entries.next, struct dma_debug_entry, list);
 357         list_del(&entry->list);
 358         memset(entry, 0, sizeof(*entry));
 359
 360         num_free_entries -= 1;
 361         if (num_free_entries < min_free_entries)
 362                 min_free_entries = num_free_entries;
 363
 364         return entry;
 365 }
 366
 367 /* struct dma_entry allocator
 368  *
 369  * The next two functions implement the allocator for
 370  * struct dma_debug_entries.
 371  */
 372 static struct dma_debug_entry *dma_entry_alloc(void)
 373 {
 374         struct dma_debug_entry *entry = NULL;
 375         unsigned long flags;
 376
 377         spin_lock_irqsave(&free_entries_lock, flags);
 378
 379         if (list_empty(&free_entries)) {
 380                 printk(KERN_ERR "DMA-API: debugging out of memory "
 381                                 "- 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         printk(KERN_INFO "DMA-API: preallocated %d debug entries\n",
 487                         num_entries);
 488
 489         return 0;
 490
 491 out_err:
 492
 493         list_for_each_entry_safe(entry, next_entry, &free_entries, list) {
 494                 list_del(&entry->list);
 495                 kfree(entry);
 496         }
 497
 498         return -ENOMEM;
 499 }
 500
 501 static ssize_t filter_read(struct file *file, char __user *user_buf,
 502                            size_t count, loff_t *ppos)
 503 {
 504         unsigned long flags;
 505         char buf[NAME_MAX_LEN + 1];
 506         int len;
 507
 508         if (!current_driver_name[0])
 509                 return 0;
 510
 511         /*
 512          * We can't copy to userspace directly because current_driver_name can
 513          * only be read under the driver_name_lock with irqs disabled. So
 514          * create a temporary copy first.
 515          */
 516         read_lock_irqsave(&driver_name_lock, flags);
 517         len = scnprintf(buf, NAME_MAX_LEN + 1, "%s\n", current_driver_name);
 518         read_unlock_irqrestore(&driver_name_lock, flags);
 519
 520         return simple_read_from_buffer(user_buf, count, ppos, buf, len);
 521 }
 522
 523 static ssize_t filter_write(struct file *file, const char __user *userbuf,
 524                             size_t count, loff_t *ppos)
 525 {
 526         unsigned long flags;
 527         char buf[NAME_MAX_LEN];
 528         size_t len = NAME_MAX_LEN - 1;
 529         int i;
 530
 531         /*
 532          * We can't copy from userspace directly. Access to
 533          * current_driver_name is protected with a write_lock with irqs
 534          * disabled. Since copy_from_user can fault and may sleep we
 535          * need to copy to temporary buffer first
 536          */
 537         len = min(count, len);
 538         if (copy_from_user(buf, userbuf, len))
 539                 return -EFAULT;
 540
 541         buf[len] = 0;
 542
 543         write_lock_irqsave(&driver_name_lock, flags);
 544
 545         /*
 546          * Now handle the string we got from userspace very carefully.
 547          * The rules are:
 548          *         - only use the first token we got
 549          *         - token delimiter is everything looking like a space
 550          *           character (' ', '\n', '\t' ...)
 551          *
 552          */
 553         if (!isalnum(buf[0])) {
 554                 /*
 555                  * If the first character userspace gave us is not
 556                  * alphanumerical then assume the filter should be
 557                  * switched off.
 558                  */
 559                 if (current_driver_name[0])
 560                         printk(KERN_INFO "DMA-API: switching off dma-debug "
 561                                          "driver filter\n");
 562                 current_driver_name[0] = 0;
 563                 current_driver = NULL;
 564                 goto out_unlock;
 565         }
 566
 567         /*
 568          * Now parse out the first token and use it as the name for the
 569          * driver to filter for.
 570          */
 571         for (i = 0; i < NAME_MAX_LEN; ++i) {
 572                 current_driver_name[i] = buf[i];
 573                 if (isspace(buf[i]) || buf[i] == ' ' || buf[i] == 0)
 574                         break;
 575         }
 576         current_driver_name[i] = 0;
 577         current_driver = NULL;
 578
 579         printk(KERN_INFO "DMA-API: enable driver filter for driver [%s]\n",
 580                current_driver_name);
 581
 582 out_unlock:
 583         write_unlock_irqrestore(&driver_name_lock, flags);
 584
 585         return count;
 586 }
 587
 588 const struct file_operations filter_fops = {
 589         .read  = filter_read,
 590         .write = filter_write,
 591 };
 592
 593 static int dma_debug_fs_init(void)
 594 {
 595         dma_debug_dent = debugfs_create_dir("dma-api", NULL);
 596         if (!dma_debug_dent) {
 597                 printk(KERN_ERR "DMA-API: can not create debugfs directory\n");
 598                 return -ENOMEM;
 599         }
 600
 601         global_disable_dent = debugfs_create_bool("disabled", 0444,
 602                         dma_debug_dent,
 603                         (u32 *)&global_disable);
 604         if (!global_disable_dent)
 605                 goto out_err;
 606
 607         error_count_dent = debugfs_create_u32("error_count", 0444,
 608                         dma_debug_dent, &error_count);
 609         if (!error_count_dent)
 610                 goto out_err;
 611
 612         show_all_errors_dent = debugfs_create_u32("all_errors", 0644,
 613                         dma_debug_dent,
 614                         &show_all_errors);
 615         if (!show_all_errors_dent)
 616                 goto out_err;
 617
 618         show_num_errors_dent = debugfs_create_u32("num_errors", 0644,
 619                         dma_debug_dent,
 620                         &show_num_errors);
 621         if (!show_num_errors_dent)
 622                 goto out_err;
 623
 624         num_free_entries_dent = debugfs_create_u32("num_free_entries", 0444,
 625                         dma_debug_dent,
 626                         &num_free_entries);
 627         if (!num_free_entries_dent)
 628                 goto out_err;
 629
 630         min_free_entries_dent = debugfs_create_u32("min_free_entries", 0444,
 631                         dma_debug_dent,
 632                         &min_free_entries);
 633         if (!min_free_entries_dent)
 634                 goto out_err;
 635
 636         filter_dent = debugfs_create_file("driver_filter", 0644,
 637                                           dma_debug_dent, NULL, &filter_fops);
 638         if (!filter_dent)
 639                 goto out_err;
 640
 641         return 0;
 642
 643 out_err:
 644         debugfs_remove_recursive(dma_debug_dent);
 645
 646         return -ENOMEM;
 647 }
 648
 649 static int device_dma_allocations(struct device *dev)
 650 {
 651         struct dma_debug_entry *entry;
 652         unsigned long flags;
 653         int count = 0, i;
 654
 655         for (i = 0; i < HASH_SIZE; ++i) {
 656                 spin_lock_irqsave(&dma_entry_hash[i].lock, flags);
 657                 list_for_each_entry(entry, &dma_entry_hash[i].list, list) {
 658                         if (entry->dev == dev)
 659                                 count += 1;
 660                 }
 661                 spin_unlock_irqrestore(&dma_entry_hash[i].lock, flags);
 662         }
 663
 664         return count;
 665 }
 666
 667 static int dma_debug_device_change(struct notifier_block *nb,
 668                                     unsigned long action, void *data)
 669 {
 670         struct device *dev = data;
 671         int count;
 672
 673
 674         switch (action) {
 675         case BUS_NOTIFY_UNBOUND_DRIVER:
 676                 count = device_dma_allocations(dev);
 677                 if (count == 0)
 678                         break;
 679                 err_printk(dev, NULL, "DMA-API: device driver has pending "
 680                                 "DMA allocations while released from device "
 681                                 "[count=%d]\n", count);
 682                 break;
 683         default:
 684                 break;
 685         }
 686
 687         return 0;
 688 }
 689
 690 void dma_debug_add_bus(struct bus_type *bus)
 691 {
 692         struct notifier_block *nb;
 693
 694         nb = kzalloc(sizeof(struct notifier_block), GFP_KERNEL);
 695         if (nb == NULL) {
 696                 printk(KERN_ERR "dma_debug_add_bus: out of memory\n");
 697                 return;
 698         }
 699
 700         nb->notifier_call = dma_debug_device_change;
 701
 702         bus_register_notifier(bus, nb);
 703 }
 704
 705 /*
 706  * Let the architectures decide how many entries should be preallocated.
 707  */
 708 void dma_debug_init(u32 num_entries)
 709 {
 710         int i;
 711
 712         if (global_disable)
 713                 return;
 714
 715         for (i = 0; i < HASH_SIZE; ++i) {
 716                 INIT_LIST_HEAD(&dma_entry_hash[i].list);
 717                 dma_entry_hash[i].lock = SPIN_LOCK_UNLOCKED;
 718         }
 719
 720         if (dma_debug_fs_init() != 0) {
 721                 printk(KERN_ERR "DMA-API: error creating debugfs entries "
 722                                 "- disabling\n");
 723                 global_disable = true;
 724
 725                 return;
 726         }
 727
 728         if (req_entries)
 729                 num_entries = req_entries;
 730
 731         if (prealloc_memory(num_entries) != 0) {
 732                 printk(KERN_ERR "DMA-API: debugging out of memory error "
 733                                 "- disabled\n");
 734                 global_disable = true;
 735
 736                 return;
 737         }
 738
 739         nr_total_entries = num_free_entries;
 740
 741         printk(KERN_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                 printk(KERN_INFO "DMA-API: debugging disabled on kernel "
 751                                  "command line\n");
 752                 global_disable = true;
 753         }
 754
 755         return 0;
 756 }
 757
 758 static __init int dma_debug_entries_cmdline(char *str)
 759 {
 760         int res;
 761
 762         if (!str)
 763                 return -EINVAL;
 764
 765         res = get_option(&str, &req_entries);
 766
 767         if (!res)
 768                 req_entries = 0;
 769
 770         return 0;
 771 }
 772
 773 __setup("dma_debug=", dma_debug_cmdline);
 774 __setup("dma_debug_entries=", dma_debug_entries_cmdline);
 775
 776 static void check_unmap(struct dma_debug_entry *ref)
 777 {
 778         struct dma_debug_entry *entry;
 779         struct hash_bucket *bucket;
 780         unsigned long flags;
 781
 782         if (dma_mapping_error(ref->dev, ref->dev_addr)) {
 783                 err_printk(ref->dev, NULL, "DMA-API: device driver tries "
 784                            "to free an invalid DMA memory address\n");
 785                 return;
 786         }
 787
 788         bucket = get_hash_bucket(ref, &flags);
 789         entry = hash_bucket_find(bucket, ref);
 790
 791         if (!entry) {
 792                 err_printk(ref->dev, NULL, "DMA-API: device driver tries "
 793                            "to free DMA memory it has not allocated "
 794                            "[device address=0x%016llx] [size=%llu bytes]\n",
 795                            ref->dev_addr, ref->size);
 796                 goto out;
 797         }
 798
 799         if (ref->size != entry->size) {
 800                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
 801                            "DMA memory with different size "
 802                            "[device address=0x%016llx] [map size=%llu bytes] "
 803                            "[unmap size=%llu bytes]\n",
 804                            ref->dev_addr, entry->size, ref->size);
 805         }
 806
 807         if (ref->type != entry->type) {
 808                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
 809                            "DMA memory with wrong function "
 810                            "[device address=0x%016llx] [size=%llu bytes] "
 811                            "[mapped as %s] [unmapped as %s]\n",
 812                            ref->dev_addr, ref->size,
 813                            type2name[entry->type], type2name[ref->type]);
 814         } else if ((entry->type == dma_debug_coherent) &&
 815                    (ref->paddr != entry->paddr)) {
 816                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
 817                            "DMA memory with different CPU address "
 818                            "[device address=0x%016llx] [size=%llu bytes] "
 819                            "[cpu alloc address=%p] [cpu free address=%p]",
 820                            ref->dev_addr, ref->size,
 821                            (void *)entry->paddr, (void *)ref->paddr);
 822         }
 823
 824         if (ref->sg_call_ents && ref->type == dma_debug_sg &&
 825             ref->sg_call_ents != entry->sg_call_ents) {
 826                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
 827                            "DMA sg list with different entry count "
 828                            "[map count=%d] [unmap count=%d]\n",
 829                            entry->sg_call_ents, ref->sg_call_ents);
 830         }
 831
 832         /*
 833          * This may be no bug in reality - but most implementations of the
 834          * DMA API don't handle this properly, so check for it here
 835          */
 836         if (ref->direction != entry->direction) {
 837                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
 838                            "DMA memory with different direction "
 839                            "[device address=0x%016llx] [size=%llu bytes] "
 840                            "[mapped with %s] [unmapped with %s]\n",
 841                            ref->dev_addr, ref->size,
 842                            dir2name[entry->direction],
 843                            dir2name[ref->direction]);
 844         }
 845
 846         hash_bucket_del(entry);
 847         dma_entry_free(entry);
 848
 849 out:
 850         put_hash_bucket(bucket, &flags);
 851 }
 852
 853 static void check_for_stack(struct device *dev, void *addr)
 854 {
 855         if (object_is_on_stack(addr))
 856                 err_printk(dev, NULL, "DMA-API: device driver maps memory from"
 857                                 "stack [addr=%p]\n", addr);
 858 }
 859
 860 static inline bool overlap(void *addr, u64 size, void *start, void *end)
 861 {
 862         void *addr2 = (char *)addr + size;
 863
 864         return ((addr >= start && addr < end) ||
 865                 (addr2 >= start && addr2 < end) ||
 866                 ((addr < start) && (addr2 >= end)));
 867 }
 868
 869 static void check_for_illegal_area(struct device *dev, void *addr, u64 size)
 870 {
 871         if (overlap(addr, size, _text, _etext) ||
 872             overlap(addr, size, __start_rodata, __end_rodata))
 873                 err_printk(dev, NULL, "DMA-API: device driver maps "
 874                                 "memory from kernel text or rodata "
 875                                 "[addr=%p] [size=%llu]\n", addr, size);
 876 }
 877
 878 static void check_sync(struct device *dev, dma_addr_t addr,
 879                        u64 size, u64 offset, int direction, bool to_cpu)
 880 {
 881         struct dma_debug_entry ref = {
 882                 .dev            = dev,
 883                 .dev_addr       = addr,
 884                 .size           = size,
 885                 .direction      = direction,
 886         };
 887         struct dma_debug_entry *entry;
 888         struct hash_bucket *bucket;
 889         unsigned long flags;
 890
 891         bucket = get_hash_bucket(&ref, &flags);
 892
 893         entry = hash_bucket_find(bucket, &ref);
 894
 895         if (!entry) {
 896                 err_printk(dev, NULL, "DMA-API: device driver tries "
 897                                 "to sync DMA memory it has not allocated "
 898                                 "[device address=0x%016llx] [size=%llu bytes]\n",
 899                                 (unsigned long long)addr, size);
 900                 goto out;
 901         }
 902
 903         if ((offset + size) > entry->size) {
 904                 err_printk(dev, entry, "DMA-API: device driver syncs"
 905                                 " DMA memory outside allocated range "
 906                                 "[device address=0x%016llx] "
 907                                 "[allocation size=%llu bytes] [sync offset=%llu] "
 908                                 "[sync size=%llu]\n", entry->dev_addr, entry->size,
 909                                 offset, size);
 910         }
 911
 912         if (direction != entry->direction) {
 913                 err_printk(dev, entry, "DMA-API: device driver syncs "
 914                                 "DMA memory with different direction "
 915                                 "[device address=0x%016llx] [size=%llu bytes] "
 916                                 "[mapped with %s] [synced with %s]\n",
 917                                 (unsigned long long)addr, entry->size,
 918                                 dir2name[entry->direction],
 919                                 dir2name[direction]);
 920         }
 921
 922         if (entry->direction == DMA_BIDIRECTIONAL)
 923                 goto out;
 924
 925         if (to_cpu && !(entry->direction == DMA_FROM_DEVICE) &&
 926                       !(direction == DMA_TO_DEVICE))
 927                 err_printk(dev, entry, "DMA-API: device driver syncs "
 928                                 "device read-only DMA memory for cpu "
 929                                 "[device address=0x%016llx] [size=%llu bytes] "
 930                                 "[mapped with %s] [synced with %s]\n",
 931                                 (unsigned long long)addr, entry->size,
 932                                 dir2name[entry->direction],
 933                                 dir2name[direction]);
 934
 935         if (!to_cpu && !(entry->direction == DMA_TO_DEVICE) &&
 936                        !(direction == DMA_FROM_DEVICE))
 937                 err_printk(dev, entry, "DMA-API: device driver syncs "
 938                                 "device write-only DMA memory to device "
 939                                 "[device address=0x%016llx] [size=%llu bytes] "
 940                                 "[mapped with %s] [synced with %s]\n",
 941                                 (unsigned long long)addr, entry->size,
 942                                 dir2name[entry->direction],
 943                                 dir2name[direction]);
 944
 945 out:
 946         put_hash_bucket(bucket, &flags);
 947
 948 }
 949
 950 void debug_dma_map_page(struct device *dev, struct page *page, size_t offset,
 951                         size_t size, int direction, dma_addr_t dma_addr,
 952                         bool map_single)
 953 {
 954         struct dma_debug_entry *entry;
 955
 956         if (unlikely(global_disable))
 957                 return;
 958
 959         if (unlikely(dma_mapping_error(dev, dma_addr)))
 960                 return;
 961
 962         entry = dma_entry_alloc();
 963         if (!entry)
 964                 return;
 965
 966         entry->dev       = dev;
 967         entry->type      = dma_debug_page;
 968         entry->paddr     = page_to_phys(page) + offset;
 969         entry->dev_addr  = dma_addr;
 970         entry->size      = size;
 971         entry->direction = direction;
 972
 973         if (map_single)
 974                 entry->type = dma_debug_single;
 975
 976         if (!PageHighMem(page)) {
 977                 void *addr = ((char *)page_address(page)) + offset;
 978                 check_for_stack(dev, addr);
 979                 check_for_illegal_area(dev, addr, size);
 980         }
 981
 982         add_dma_entry(entry);
 983 }
 984 EXPORT_SYMBOL(debug_dma_map_page);
 985
 986 void debug_dma_unmap_page(struct device *dev, dma_addr_t addr,
 987                           size_t size, int direction, bool map_single)
 988 {
 989         struct dma_debug_entry ref = {
 990                 .type           = dma_debug_page,
 991                 .dev            = dev,
 992                 .dev_addr       = addr,
 993                 .size           = size,
 994                 .direction      = direction,
 995         };
 996
 997         if (unlikely(global_disable))
 998                 return;
 999
1000         if (map_single)
1001                 ref.type = dma_debug_single;
1002
1003         check_unmap(&ref);
1004 }
1005 EXPORT_SYMBOL(debug_dma_unmap_page);
1006
1007 void debug_dma_map_sg(struct device *dev, struct scatterlist *sg,
1008                       int nents, int mapped_ents, int direction)
1009 {
1010         struct dma_debug_entry *entry;
1011         struct scatterlist *s;
1012         int i;
1013
1014         if (unlikely(global_disable))
1015                 return;
1016
1017         for_each_sg(sg, s, mapped_ents, i) {
1018                 entry = dma_entry_alloc();
1019                 if (!entry)
1020                         return;
1021
1022                 entry->type           = dma_debug_sg;
1023                 entry->dev            = dev;
1024                 entry->paddr          = sg_phys(s);
1025                 entry->size           = sg_dma_len(s);
1026                 entry->dev_addr       = sg_dma_address(s);
1027                 entry->direction      = direction;
1028                 entry->sg_call_ents   = nents;
1029                 entry->sg_mapped_ents = mapped_ents;
1030
1031                 if (!PageHighMem(sg_page(s))) {
1032                         check_for_stack(dev, sg_virt(s));
1033                         check_for_illegal_area(dev, sg_virt(s), sg_dma_len(s));
1034                 }
1035
1036                 add_dma_entry(entry);
1037         }
1038 }
1039 EXPORT_SYMBOL(debug_dma_map_sg);
1040
1041 static int get_nr_mapped_entries(struct device *dev, struct scatterlist *s)
1042 {
1043         struct dma_debug_entry *entry;
1044         struct hash_bucket *bucket;
1045         unsigned long flags;
1046         int mapped_ents = 0;
1047         struct dma_debug_entry ref;
1048
1049         ref.dev = dev;
1050         ref.dev_addr = sg_dma_address(s);
1051         ref.size = sg_dma_len(s),
1052
1053         bucket = get_hash_bucket(&ref, &flags);
1054         entry = hash_bucket_find(bucket, &ref);
1055         if (entry)
1056                 mapped_ents = entry->sg_mapped_ents;
1057         put_hash_bucket(bucket, &flags);
1058
1059         return mapped_ents;
1060 }
1061
1062 void debug_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
1063                         int nelems, int dir)
1064 {
1065         struct scatterlist *s;
1066         int mapped_ents = 0, i;
1067
1068         if (unlikely(global_disable))
1069                 return;
1070
1071         for_each_sg(sglist, s, nelems, i) {
1072
1073                 struct dma_debug_entry ref = {
1074                         .type           = dma_debug_sg,
1075                         .dev            = dev,
1076                         .paddr          = sg_phys(s),
1077                         .dev_addr       = sg_dma_address(s),
1078                         .size           = sg_dma_len(s),
1079                         .direction      = dir,
1080                         .sg_call_ents   = 0,
1081                 };
1082
1083                 if (mapped_ents && i >= mapped_ents)
1084                         break;
1085
1086                 if (!i) {
1087                         ref.sg_call_ents = nelems;
1088                         mapped_ents = get_nr_mapped_entries(dev, s);
1089                 }
1090
1091                 check_unmap(&ref);
1092         }
1093 }
1094 EXPORT_SYMBOL(debug_dma_unmap_sg);
1095
1096 void debug_dma_alloc_coherent(struct device *dev, size_t size,
1097                               dma_addr_t dma_addr, void *virt)
1098 {
1099         struct dma_debug_entry *entry;
1100
1101         if (unlikely(global_disable))
1102                 return;
1103
1104         if (unlikely(virt == NULL))
1105                 return;
1106
1107         entry = dma_entry_alloc();
1108         if (!entry)
1109                 return;
1110
1111         entry->type      = dma_debug_coherent;
1112         entry->dev       = dev;
1113         entry->paddr     = virt_to_phys(virt);
1114         entry->size      = size;
1115         entry->dev_addr  = dma_addr;
1116         entry->direction = DMA_BIDIRECTIONAL;
1117
1118         add_dma_entry(entry);
1119 }
1120 EXPORT_SYMBOL(debug_dma_alloc_coherent);
1121
1122 void debug_dma_free_coherent(struct device *dev, size_t size,
1123                          void *virt, dma_addr_t addr)
1124 {
1125         struct dma_debug_entry ref = {
1126                 .type           = dma_debug_coherent,
1127                 .dev            = dev,
1128                 .paddr          = virt_to_phys(virt),
1129                 .dev_addr       = addr,
1130                 .size           = size,
1131                 .direction      = DMA_BIDIRECTIONAL,
1132         };
1133
1134         if (unlikely(global_disable))
1135                 return;
1136
1137         check_unmap(&ref);
1138 }
1139 EXPORT_SYMBOL(debug_dma_free_coherent);
1140
1141 void debug_dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_handle,
1142                                    size_t size, int direction)
1143 {
1144         if (unlikely(global_disable))
1145                 return;
1146
1147         check_sync(dev, dma_handle, size, 0, direction, 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         if (unlikely(global_disable))
1156                 return;
1157
1158         check_sync(dev, dma_handle, size, 0, direction, false);
1159 }
1160 EXPORT_SYMBOL(debug_dma_sync_single_for_device);
1161
1162 void debug_dma_sync_single_range_for_cpu(struct device *dev,
1163                                          dma_addr_t dma_handle,
1164                                          unsigned long offset, size_t size,
1165                                          int direction)
1166 {
1167         if (unlikely(global_disable))
1168                 return;
1169
1170         check_sync(dev, dma_handle, size, offset, direction, true);
1171 }
1172 EXPORT_SYMBOL(debug_dma_sync_single_range_for_cpu);
1173
1174 void debug_dma_sync_single_range_for_device(struct device *dev,
1175                                             dma_addr_t dma_handle,
1176                                             unsigned long offset,
1177                                             size_t size, int direction)
1178 {
1179         if (unlikely(global_disable))
1180                 return;
1181
1182         check_sync(dev, dma_handle, size, offset, direction, false);
1183 }
1184 EXPORT_SYMBOL(debug_dma_sync_single_range_for_device);
1185
1186 void debug_dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
1187                                int nelems, int direction)
1188 {
1189         struct scatterlist *s;
1190         int mapped_ents = 0, i;
1191
1192         if (unlikely(global_disable))
1193                 return;
1194
1195         for_each_sg(sg, s, nelems, i) {
1196                 if (!i)
1197                         mapped_ents = get_nr_mapped_entries(dev, s);
1198
1199                 if (i >= mapped_ents)
1200                         break;
1201
1202                 check_sync(dev, sg_dma_address(s), sg_dma_len(s), 0,
1203                            direction, true);
1204         }
1205 }
1206 EXPORT_SYMBOL(debug_dma_sync_sg_for_cpu);
1207
1208 void debug_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
1209                                   int nelems, int direction)
1210 {
1211         struct scatterlist *s;
1212         int mapped_ents = 0, i;
1213
1214         if (unlikely(global_disable))
1215                 return;
1216
1217         for_each_sg(sg, s, nelems, i) {
1218                 if (!i)
1219                         mapped_ents = get_nr_mapped_entries(dev, s);
1220
1221                 if (i >= mapped_ents)
1222                         break;
1223
1224                 check_sync(dev, sg_dma_address(s), sg_dma_len(s), 0,
1225                            direction, false);
1226         }
1227 }
1228 EXPORT_SYMBOL(debug_dma_sync_sg_for_device);
1229
1230 static int __init dma_debug_driver_setup(char *str)
1231 {
1232         int i;
1233
1234         for (i = 0; i < NAME_MAX_LEN - 1; ++i, ++str) {
1235                 current_driver_name[i] = *str;
1236                 if (*str == 0)
1237                         break;
1238         }
1239
1240         if (current_driver_name[0])
1241                 printk(KERN_INFO "DMA-API: enable driver filter for "
1242                                  "driver [%s]\n", current_driver_name);
1243
1244
1245         return 1;
1246 }
1247 __setup("dma_debug_driver=", dma_debug_driver_setup);