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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 /*
 121  * The access to some variables in this macro is racy. We can't use atomic_t
 122  * here because all these variables are exported to debugfs. Some of them even
 123  * writeable. This is also the reason why a lock won't help much. But anyway,
 124  * the races are no big deal. Here is why:
 125  *
 126  *   error_count: the addition is racy, but the worst thing that can happen is
 127  *                that we don't count some errors
 128  *   show_num_errors: the subtraction is racy. Also no big deal because in
 129  *                    worst case this will result in one warning more in the
 130  *                    system log than the user configured. This variable is
 131  *                    writeable via debugfs.
 132  */
 133 static inline void dump_entry_trace(struct dma_debug_entry *entry)
 134 {
 135 #ifdef CONFIG_STACKTRACE
 136         if (entry) {
 137                 printk(KERN_WARNING "Mapped at:\n");
 138                 print_stack_trace(&entry->stacktrace, 0);
 139         }
 140 #endif
 141 }
 142
 143 static bool driver_filter(struct device *dev)
 144 {
 145         /* driver filter off */
 146         if (likely(!current_driver_name[0]))
 147                 return true;
 148
 149         /* driver filter on and initialized */
 150         if (current_driver && dev->driver == current_driver)
 151                 return true;
 152
 153         /* driver filter on but not yet initialized */
 154         if (!current_driver && current_driver_name[0]) {
 155                 struct device_driver *drv = get_driver(dev->driver);
 156                 unsigned long flags;
 157                 bool ret = false;
 158
 159                 if (!drv)
 160                         return false;
 161
 162                 /* lock to protect against change of current_driver_name */
 163                 read_lock_irqsave(&driver_name_lock, flags);
 164
 165                 if (drv->name &&
 166                     strncmp(current_driver_name, drv->name,
 167                             NAME_MAX_LEN-1) == 0) {
 168                         current_driver = drv;
 169                         ret = true;
 170                 }
 171
 172                 read_unlock_irqrestore(&driver_name_lock, flags);
 173                 put_driver(drv);
 174
 175                 return ret;
 176         }
 177
 178         return false;
 179 }
 180
 181 #define err_printk(dev, entry, format, arg...) do {             \
 182                 error_count += 1;                               \
 183                 if (driver_filter(dev) &&                       \
 184                     (show_all_errors || show_num_errors > 0)) { \
 185                         WARN(1, "%s %s: " format,               \
 186                              dev_driver_string(dev),            \
 187                              dev_name(dev) , ## arg);           \
 188                         dump_entry_trace(entry);                \
 189                 }                                               \
 190                 if (!show_all_errors && show_num_errors > 0)    \
 191                         show_num_errors -= 1;                   \
 192         } while (0);
 193
 194 /*
 195  * Hash related functions
 196  *
 197  * Every DMA-API request is saved into a struct dma_debug_entry. To
 198  * have quick access to these structs they are stored into a hash.
 199  */
 200 static int hash_fn(struct dma_debug_entry *entry)
 201 {
 202         /*
 203          * Hash function is based on the dma address.
 204          * We use bits 20-27 here as the index into the hash
 205          */
 206         return (entry->dev_addr >> HASH_FN_SHIFT) & HASH_FN_MASK;
 207 }
 208
 209 /*
 210  * Request exclusive access to a hash bucket for a given dma_debug_entry.
 211  */
 212 static struct hash_bucket *get_hash_bucket(struct dma_debug_entry *entry,
 213                                            unsigned long *flags)
 214 {
 215         int idx = hash_fn(entry);
 216         unsigned long __flags;
 217
 218         spin_lock_irqsave(&dma_entry_hash[idx].lock, __flags);
 219         *flags = __flags;
 220         return &dma_entry_hash[idx];
 221 }
 222
 223 /*
 224  * Give up exclusive access to the hash bucket
 225  */
 226 static void put_hash_bucket(struct hash_bucket *bucket,
 227                             unsigned long *flags)
 228 {
 229         unsigned long __flags = *flags;
 230
 231         spin_unlock_irqrestore(&bucket->lock, __flags);
 232 }
 233
 234 /*
 235  * Search a given entry in the hash bucket list
 236  */
 237 static struct dma_debug_entry *hash_bucket_find(struct hash_bucket *bucket,
 238                                                 struct dma_debug_entry *ref)
 239 {
 240         struct dma_debug_entry *entry;
 241
 242         list_for_each_entry(entry, &bucket->list, list) {
 243                 if ((entry->dev_addr == ref->dev_addr) &&
 244                     (entry->dev == ref->dev))
 245                         return entry;
 246         }
 247
 248         return NULL;
 249 }
 250
 251 /*
 252  * Add an entry to a hash bucket
 253  */
 254 static void hash_bucket_add(struct hash_bucket *bucket,
 255                             struct dma_debug_entry *entry)
 256 {
 257         list_add_tail(&entry->list, &bucket->list);
 258 }
 259
 260 /*
 261  * Remove entry from a hash bucket list
 262  */
 263 static void hash_bucket_del(struct dma_debug_entry *entry)
 264 {
 265         list_del(&entry->list);
 266 }
 267
 268 /*
 269  * Dump mapping entries for debugging purposes
 270  */
 271 void debug_dma_dump_mappings(struct device *dev)
 272 {
 273         int idx;
 274
 275         for (idx = 0; idx < HASH_SIZE; idx++) {
 276                 struct hash_bucket *bucket = &dma_entry_hash[idx];
 277                 struct dma_debug_entry *entry;
 278                 unsigned long flags;
 279
 280                 spin_lock_irqsave(&bucket->lock, flags);
 281
 282                 list_for_each_entry(entry, &bucket->list, list) {
 283                         if (!dev || dev == entry->dev) {
 284                                 dev_info(entry->dev,
 285                                          "%s idx %d P=%Lx D=%Lx L=%Lx %s\n",
 286                                          type2name[entry->type], idx,
 287                                          (unsigned long long)entry->paddr,
 288                                          entry->dev_addr, entry->size,
 289                                          dir2name[entry->direction]);
 290                         }
 291                 }
 292
 293                 spin_unlock_irqrestore(&bucket->lock, flags);
 294         }
 295 }
 296 EXPORT_SYMBOL(debug_dma_dump_mappings);
 297
 298 /*
 299  * Wrapper function for adding an entry to the hash.
 300  * This function takes care of locking itself.
 301  */
 302 static void add_dma_entry(struct dma_debug_entry *entry)
 303 {
 304         struct hash_bucket *bucket;
 305         unsigned long flags;
 306
 307         bucket = get_hash_bucket(entry, &flags);
 308         hash_bucket_add(bucket, entry);
 309         put_hash_bucket(bucket, &flags);
 310 }
 311
 312 static struct dma_debug_entry *__dma_entry_alloc(void)
 313 {
 314         struct dma_debug_entry *entry;
 315
 316         entry = list_entry(free_entries.next, struct dma_debug_entry, list);
 317         list_del(&entry->list);
 318         memset(entry, 0, sizeof(*entry));
 319
 320         num_free_entries -= 1;
 321         if (num_free_entries < min_free_entries)
 322                 min_free_entries = num_free_entries;
 323
 324         return entry;
 325 }
 326
 327 /* struct dma_entry allocator
 328  *
 329  * The next two functions implement the allocator for
 330  * struct dma_debug_entries.
 331  */
 332 static struct dma_debug_entry *dma_entry_alloc(void)
 333 {
 334         struct dma_debug_entry *entry = NULL;
 335         unsigned long flags;
 336
 337         spin_lock_irqsave(&free_entries_lock, flags);
 338
 339         if (list_empty(&free_entries)) {
 340                 printk(KERN_ERR "DMA-API: debugging out of memory "
 341                                 "- disabling\n");
 342                 global_disable = true;
 343                 goto out;
 344         }
 345
 346         entry = __dma_entry_alloc();
 347
 348 #ifdef CONFIG_STACKTRACE
 349         entry->stacktrace.max_entries = DMA_DEBUG_STACKTRACE_ENTRIES;
 350         entry->stacktrace.entries = entry->st_entries;
 351         entry->stacktrace.skip = 2;
 352         save_stack_trace(&entry->stacktrace);
 353 #endif
 354
 355 out:
 356         spin_unlock_irqrestore(&free_entries_lock, flags);
 357
 358         return entry;
 359 }
 360
 361 static void dma_entry_free(struct dma_debug_entry *entry)
 362 {
 363         unsigned long flags;
 364
 365         /*
 366          * add to beginning of the list - this way the entries are
 367          * more likely cache hot when they are reallocated.
 368          */
 369         spin_lock_irqsave(&free_entries_lock, flags);
 370         list_add(&entry->list, &free_entries);
 371         num_free_entries += 1;
 372         spin_unlock_irqrestore(&free_entries_lock, flags);
 373 }
 374
 375 int dma_debug_resize_entries(u32 num_entries)
 376 {
 377         int i, delta, ret = 0;
 378         unsigned long flags;
 379         struct dma_debug_entry *entry;
 380         LIST_HEAD(tmp);
 381
 382         spin_lock_irqsave(&free_entries_lock, flags);
 383
 384         if (nr_total_entries < num_entries) {
 385                 delta = num_entries - nr_total_entries;
 386
 387                 spin_unlock_irqrestore(&free_entries_lock, flags);
 388
 389                 for (i = 0; i < delta; i++) {
 390                         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 391                         if (!entry)
 392                                 break;
 393
 394                         list_add_tail(&entry->list, &tmp);
 395                 }
 396
 397                 spin_lock_irqsave(&free_entries_lock, flags);
 398
 399                 list_splice(&tmp, &free_entries);
 400                 nr_total_entries += i;
 401                 num_free_entries += i;
 402         } else {
 403                 delta = nr_total_entries - num_entries;
 404
 405                 for (i = 0; i < delta && !list_empty(&free_entries); i++) {
 406                         entry = __dma_entry_alloc();
 407                         kfree(entry);
 408                 }
 409
 410                 nr_total_entries -= i;
 411         }
 412
 413         if (nr_total_entries != num_entries)
 414                 ret = 1;
 415
 416         spin_unlock_irqrestore(&free_entries_lock, flags);
 417
 418         return ret;
 419 }
 420 EXPORT_SYMBOL(dma_debug_resize_entries);
 421
 422 /*
 423  * DMA-API debugging init code
 424  *
 425  * The init code does two things:
 426  *   1. Initialize core data structures
 427  *   2. Preallocate a given number of dma_debug_entry structs
 428  */
 429
 430 static int prealloc_memory(u32 num_entries)
 431 {
 432         struct dma_debug_entry *entry, *next_entry;
 433         int i;
 434
 435         for (i = 0; i < num_entries; ++i) {
 436                 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 437                 if (!entry)
 438                         goto out_err;
 439
 440                 list_add_tail(&entry->list, &free_entries);
 441         }
 442
 443         num_free_entries = num_entries;
 444         min_free_entries = num_entries;
 445
 446         printk(KERN_INFO "DMA-API: preallocated %d debug entries\n",
 447                         num_entries);
 448
 449         return 0;
 450
 451 out_err:
 452
 453         list_for_each_entry_safe(entry, next_entry, &free_entries, list) {
 454                 list_del(&entry->list);
 455                 kfree(entry);
 456         }
 457
 458         return -ENOMEM;
 459 }
 460
 461 static ssize_t filter_read(struct file *file, char __user *user_buf,
 462                            size_t count, loff_t *ppos)
 463 {
 464         unsigned long flags;
 465         char buf[NAME_MAX_LEN + 1];
 466         int len;
 467
 468         if (!current_driver_name[0])
 469                 return 0;
 470
 471         /*
 472          * We can't copy to userspace directly because current_driver_name can
 473          * only be read under the driver_name_lock with irqs disabled. So
 474          * create a temporary copy first.
 475          */
 476         read_lock_irqsave(&driver_name_lock, flags);
 477         len = scnprintf(buf, NAME_MAX_LEN + 1, "%s\n", current_driver_name);
 478         read_unlock_irqrestore(&driver_name_lock, flags);
 479
 480         return simple_read_from_buffer(user_buf, count, ppos, buf, len);
 481 }
 482
 483 static ssize_t filter_write(struct file *file, const char __user *userbuf,
 484                             size_t count, loff_t *ppos)
 485 {
 486         unsigned long flags;
 487         char buf[NAME_MAX_LEN];
 488         size_t len = NAME_MAX_LEN - 1;
 489         int i;
 490
 491         /*
 492          * We can't copy from userspace directly. Access to
 493          * current_driver_name is protected with a write_lock with irqs
 494          * disabled. Since copy_from_user can fault and may sleep we
 495          * need to copy to temporary buffer first
 496          */
 497         len = min(count, len);
 498         if (copy_from_user(buf, userbuf, len))
 499                 return -EFAULT;
 500
 501         buf[len] = 0;
 502
 503         write_lock_irqsave(&driver_name_lock, flags);
 504
 505         /* Now handle the string we got from userspace very carefully.
 506          * The rules are:
 507          *         - only use the first token we got
 508          *         - token delimiter is everything looking like a space
 509          *           character (' ', '\n', '\t' ...)
 510          *
 511          */
 512         if (!isalnum(buf[0])) {
 513                 /*
 514                    If the first character userspace gave us is not
 515                  * alphanumerical then assume the filter should be
 516                  * switched off.
 517                  */
 518                 if (current_driver_name[0])
 519                         printk(KERN_INFO "DMA-API: switching off dma-debug "
 520                                          "driver filter\n");
 521                 current_driver_name[0] = 0;
 522                 current_driver = NULL;
 523                 goto out_unlock;
 524         }
 525
 526         /*
 527          * Now parse out the first token and use it as the name for the
 528          * driver to filter for.
 529          */
 530         for (i = 0; i < NAME_MAX_LEN; ++i) {
 531                 current_driver_name[i] = buf[i];
 532                 if (isspace(buf[i]) || buf[i] == ' ' || buf[i] == 0)
 533                         break;
 534         }
 535         current_driver_name[i] = 0;
 536         current_driver = NULL;
 537
 538         printk(KERN_INFO "DMA-API: enable driver filter for driver [%s]\n",
 539                current_driver_name);
 540
 541 out_unlock:
 542         write_unlock_irqrestore(&driver_name_lock, flags);
 543
 544         return count;
 545 }
 546
 547 const struct file_operations filter_fops = {
 548         .read  = filter_read,
 549         .write = filter_write,
 550 };
 551
 552 static int dma_debug_fs_init(void)
 553 {
 554         dma_debug_dent = debugfs_create_dir("dma-api", NULL);
 555         if (!dma_debug_dent) {
 556                 printk(KERN_ERR "DMA-API: can not create debugfs directory\n");
 557                 return -ENOMEM;
 558         }
 559
 560         global_disable_dent = debugfs_create_bool("disabled", 0444,
 561                         dma_debug_dent,
 562                         (u32 *)&global_disable);
 563         if (!global_disable_dent)
 564                 goto out_err;
 565
 566         error_count_dent = debugfs_create_u32("error_count", 0444,
 567                         dma_debug_dent, &error_count);
 568         if (!error_count_dent)
 569                 goto out_err;
 570
 571         show_all_errors_dent = debugfs_create_u32("all_errors", 0644,
 572                         dma_debug_dent,
 573                         &show_all_errors);
 574         if (!show_all_errors_dent)
 575                 goto out_err;
 576
 577         show_num_errors_dent = debugfs_create_u32("num_errors", 0644,
 578                         dma_debug_dent,
 579                         &show_num_errors);
 580         if (!show_num_errors_dent)
 581                 goto out_err;
 582
 583         num_free_entries_dent = debugfs_create_u32("num_free_entries", 0444,
 584                         dma_debug_dent,
 585                         &num_free_entries);
 586         if (!num_free_entries_dent)
 587                 goto out_err;
 588
 589         min_free_entries_dent = debugfs_create_u32("min_free_entries", 0444,
 590                         dma_debug_dent,
 591                         &min_free_entries);
 592         if (!min_free_entries_dent)
 593                 goto out_err;
 594
 595         filter_dent = debugfs_create_file("driver_filter", 0644,
 596                                           dma_debug_dent, NULL, &filter_fops);
 597         if (!filter_dent)
 598                 goto out_err;
 599
 600         return 0;
 601
 602 out_err:
 603         debugfs_remove_recursive(dma_debug_dent);
 604
 605         return -ENOMEM;
 606 }
 607
 608 void dma_debug_add_bus(struct bus_type *bus)
 609 {
 610         /* FIXME: register notifier */
 611 }
 612
 613 /*
 614  * Let the architectures decide how many entries should be preallocated.
 615  */
 616 void dma_debug_init(u32 num_entries)
 617 {
 618         int i;
 619
 620         if (global_disable)
 621                 return;
 622
 623         for (i = 0; i < HASH_SIZE; ++i) {
 624                 INIT_LIST_HEAD(&dma_entry_hash[i].list);
 625                 dma_entry_hash[i].lock = SPIN_LOCK_UNLOCKED;
 626         }
 627
 628         if (dma_debug_fs_init() != 0) {
 629                 printk(KERN_ERR "DMA-API: error creating debugfs entries "
 630                                 "- disabling\n");
 631                 global_disable = true;
 632
 633                 return;
 634         }
 635
 636         if (req_entries)
 637                 num_entries = req_entries;
 638
 639         if (prealloc_memory(num_entries) != 0) {
 640                 printk(KERN_ERR "DMA-API: debugging out of memory error "
 641                                 "- disabled\n");
 642                 global_disable = true;
 643
 644                 return;
 645         }
 646
 647         nr_total_entries = num_free_entries;
 648
 649         printk(KERN_INFO "DMA-API: debugging enabled by kernel config\n");
 650 }
 651
 652 static __init int dma_debug_cmdline(char *str)
 653 {
 654         if (!str)
 655                 return -EINVAL;
 656
 657         if (strncmp(str, "off", 3) == 0) {
 658                 printk(KERN_INFO "DMA-API: debugging disabled on kernel "
 659                                  "command line\n");
 660                 global_disable = true;
 661         }
 662
 663         return 0;
 664 }
 665
 666 static __init int dma_debug_entries_cmdline(char *str)
 667 {
 668         int res;
 669
 670         if (!str)
 671                 return -EINVAL;
 672
 673         res = get_option(&str, &req_entries);
 674
 675         if (!res)
 676                 req_entries = 0;
 677
 678         return 0;
 679 }
 680
 681 __setup("dma_debug=", dma_debug_cmdline);
 682 __setup("dma_debug_entries=", dma_debug_entries_cmdline);
 683
 684 static void check_unmap(struct dma_debug_entry *ref)
 685 {
 686         struct dma_debug_entry *entry;
 687         struct hash_bucket *bucket;
 688         unsigned long flags;
 689
 690         if (dma_mapping_error(ref->dev, ref->dev_addr)) {
 691                 err_printk(ref->dev, NULL, "DMA-API: device driver tries "
 692                            "to free an invalid DMA memory address\n");
 693                 return;
 694         }
 695
 696         bucket = get_hash_bucket(ref, &flags);
 697         entry = hash_bucket_find(bucket, ref);
 698
 699         if (!entry) {
 700                 err_printk(ref->dev, NULL, "DMA-API: device driver tries "
 701                            "to free DMA memory it has not allocated "
 702                            "[device address=0x%016llx] [size=%llu bytes]\n",
 703                            ref->dev_addr, ref->size);
 704                 goto out;
 705         }
 706
 707         if (ref->size != entry->size) {
 708                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
 709                            "DMA memory with different size "
 710                            "[device address=0x%016llx] [map size=%llu bytes] "
 711                            "[unmap size=%llu bytes]\n",
 712                            ref->dev_addr, entry->size, ref->size);
 713         }
 714
 715         if (ref->type != entry->type) {
 716                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
 717                            "DMA memory with wrong function "
 718                            "[device address=0x%016llx] [size=%llu bytes] "
 719                            "[mapped as %s] [unmapped as %s]\n",
 720                            ref->dev_addr, ref->size,
 721                            type2name[entry->type], type2name[ref->type]);
 722         } else if ((entry->type == dma_debug_coherent) &&
 723                    (ref->paddr != entry->paddr)) {
 724                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
 725                            "DMA memory with different CPU address "
 726                            "[device address=0x%016llx] [size=%llu bytes] "
 727                            "[cpu alloc address=%p] [cpu free address=%p]",
 728                            ref->dev_addr, ref->size,
 729                            (void *)entry->paddr, (void *)ref->paddr);
 730         }
 731
 732         if (ref->sg_call_ents && ref->type == dma_debug_sg &&
 733             ref->sg_call_ents != entry->sg_call_ents) {
 734                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
 735                            "DMA sg list with different entry count "
 736                            "[map count=%d] [unmap count=%d]\n",
 737                            entry->sg_call_ents, ref->sg_call_ents);
 738         }
 739
 740         /*
 741          * This may be no bug in reality - but most implementations of the
 742          * DMA API don't handle this properly, so check for it here
 743          */
 744         if (ref->direction != entry->direction) {
 745                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
 746                            "DMA memory with different direction "
 747                            "[device address=0x%016llx] [size=%llu bytes] "
 748                            "[mapped with %s] [unmapped with %s]\n",
 749                            ref->dev_addr, ref->size,
 750                            dir2name[entry->direction],
 751                            dir2name[ref->direction]);
 752         }
 753
 754         hash_bucket_del(entry);
 755         dma_entry_free(entry);
 756
 757 out:
 758         put_hash_bucket(bucket, &flags);
 759 }
 760
 761 static void check_for_stack(struct device *dev, void *addr)
 762 {
 763         if (object_is_on_stack(addr))
 764                 err_printk(dev, NULL, "DMA-API: device driver maps memory from"
 765                                 "stack [addr=%p]\n", addr);
 766 }
 767
 768 static inline bool overlap(void *addr, u64 size, void *start, void *end)
 769 {
 770         void *addr2 = (char *)addr + size;
 771
 772         return ((addr >= start && addr < end) ||
 773                 (addr2 >= start && addr2 < end) ||
 774                 ((addr < start) && (addr2 >= end)));
 775 }
 776
 777 static void check_for_illegal_area(struct device *dev, void *addr, u64 size)
 778 {
 779         if (overlap(addr, size, _text, _etext) ||
 780             overlap(addr, size, __start_rodata, __end_rodata))
 781                 err_printk(dev, NULL, "DMA-API: device driver maps "
 782                                 "memory from kernel text or rodata "
 783                                 "[addr=%p] [size=%llu]\n", addr, size);
 784 }
 785
 786 static void check_sync(struct device *dev, dma_addr_t addr,
 787                        u64 size, u64 offset, int direction, bool to_cpu)
 788 {
 789         struct dma_debug_entry ref = {
 790                 .dev            = dev,
 791                 .dev_addr       = addr,
 792                 .size           = size,
 793                 .direction      = direction,
 794         };
 795         struct dma_debug_entry *entry;
 796         struct hash_bucket *bucket;
 797         unsigned long flags;
 798
 799         bucket = get_hash_bucket(&ref, &flags);
 800
 801         entry = hash_bucket_find(bucket, &ref);
 802
 803         if (!entry) {
 804                 err_printk(dev, NULL, "DMA-API: device driver tries "
 805                                 "to sync DMA memory it has not allocated "
 806                                 "[device address=0x%016llx] [size=%llu bytes]\n",
 807                                 (unsigned long long)addr, size);
 808                 goto out;
 809         }
 810
 811         if ((offset + size) > entry->size) {
 812                 err_printk(dev, entry, "DMA-API: device driver syncs"
 813                                 " DMA memory outside allocated range "
 814                                 "[device address=0x%016llx] "
 815                                 "[allocation size=%llu bytes] [sync offset=%llu] "
 816                                 "[sync size=%llu]\n", entry->dev_addr, entry->size,
 817                                 offset, size);
 818         }
 819
 820         if (direction != entry->direction) {
 821                 err_printk(dev, entry, "DMA-API: device driver syncs "
 822                                 "DMA memory with different direction "
 823                                 "[device address=0x%016llx] [size=%llu bytes] "
 824                                 "[mapped with %s] [synced with %s]\n",
 825                                 (unsigned long long)addr, entry->size,
 826                                 dir2name[entry->direction],
 827                                 dir2name[direction]);
 828         }
 829
 830         if (entry->direction == DMA_BIDIRECTIONAL)
 831                 goto out;
 832
 833         if (to_cpu && !(entry->direction == DMA_FROM_DEVICE) &&
 834                       !(direction == DMA_TO_DEVICE))
 835                 err_printk(dev, entry, "DMA-API: device driver syncs "
 836                                 "device read-only DMA memory for cpu "
 837                                 "[device address=0x%016llx] [size=%llu bytes] "
 838                                 "[mapped with %s] [synced with %s]\n",
 839                                 (unsigned long long)addr, entry->size,
 840                                 dir2name[entry->direction],
 841                                 dir2name[direction]);
 842
 843         if (!to_cpu && !(entry->direction == DMA_TO_DEVICE) &&
 844                        !(direction == DMA_FROM_DEVICE))
 845                 err_printk(dev, entry, "DMA-API: device driver syncs "
 846                                 "device write-only DMA memory to device "
 847                                 "[device address=0x%016llx] [size=%llu bytes] "
 848                                 "[mapped with %s] [synced with %s]\n",
 849                                 (unsigned long long)addr, entry->size,
 850                                 dir2name[entry->direction],
 851                                 dir2name[direction]);
 852
 853 out:
 854         put_hash_bucket(bucket, &flags);
 855
 856 }
 857
 858 void debug_dma_map_page(struct device *dev, struct page *page, size_t offset,
 859                         size_t size, int direction, dma_addr_t dma_addr,
 860                         bool map_single)
 861 {
 862         struct dma_debug_entry *entry;
 863
 864         if (unlikely(global_disable))
 865                 return;
 866
 867         if (unlikely(dma_mapping_error(dev, dma_addr)))
 868                 return;
 869
 870         entry = dma_entry_alloc();
 871         if (!entry)
 872                 return;
 873
 874         entry->dev       = dev;
 875         entry->type      = dma_debug_page;
 876         entry->paddr     = page_to_phys(page) + offset;
 877         entry->dev_addr  = dma_addr;
 878         entry->size      = size;
 879         entry->direction = direction;
 880
 881         if (map_single)
 882                 entry->type = dma_debug_single;
 883
 884         if (!PageHighMem(page)) {
 885                 void *addr = ((char *)page_address(page)) + offset;
 886                 check_for_stack(dev, addr);
 887                 check_for_illegal_area(dev, addr, size);
 888         }
 889
 890         add_dma_entry(entry);
 891 }
 892 EXPORT_SYMBOL(debug_dma_map_page);
 893
 894 void debug_dma_unmap_page(struct device *dev, dma_addr_t addr,
 895                           size_t size, int direction, bool map_single)
 896 {
 897         struct dma_debug_entry ref = {
 898                 .type           = dma_debug_page,
 899                 .dev            = dev,
 900                 .dev_addr       = addr,
 901                 .size           = size,
 902                 .direction      = direction,
 903         };
 904
 905         if (unlikely(global_disable))
 906                 return;
 907
 908         if (map_single)
 909                 ref.type = dma_debug_single;
 910
 911         check_unmap(&ref);
 912 }
 913 EXPORT_SYMBOL(debug_dma_unmap_page);
 914
 915 void debug_dma_map_sg(struct device *dev, struct scatterlist *sg,
 916                       int nents, int mapped_ents, int direction)
 917 {
 918         struct dma_debug_entry *entry;
 919         struct scatterlist *s;
 920         int i;
 921
 922         if (unlikely(global_disable))
 923                 return;
 924
 925         for_each_sg(sg, s, mapped_ents, i) {
 926                 entry = dma_entry_alloc();
 927                 if (!entry)
 928                         return;
 929
 930                 entry->type           = dma_debug_sg;
 931                 entry->dev            = dev;
 932                 entry->paddr          = sg_phys(s);
 933                 entry->size           = s->length;
 934                 entry->dev_addr       = s->dma_address;
 935                 entry->direction      = direction;
 936                 entry->sg_call_ents   = nents;
 937                 entry->sg_mapped_ents = mapped_ents;
 938
 939                 if (!PageHighMem(sg_page(s))) {
 940                         check_for_stack(dev, sg_virt(s));
 941                         check_for_illegal_area(dev, sg_virt(s), s->length);
 942                 }
 943
 944                 add_dma_entry(entry);
 945         }
 946 }
 947 EXPORT_SYMBOL(debug_dma_map_sg);
 948
 949 void debug_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
 950                         int nelems, int dir)
 951 {
 952         struct dma_debug_entry *entry;
 953         struct scatterlist *s;
 954         int mapped_ents = 0, i;
 955         unsigned long flags;
 956
 957         if (unlikely(global_disable))
 958                 return;
 959
 960         for_each_sg(sglist, s, nelems, i) {
 961
 962                 struct dma_debug_entry ref = {
 963                         .type           = dma_debug_sg,
 964                         .dev            = dev,
 965                         .paddr          = sg_phys(s),
 966                         .dev_addr       = s->dma_address,
 967                         .size           = s->length,
 968                         .direction      = dir,
 969                         .sg_call_ents   = 0,
 970                 };
 971
 972                 if (mapped_ents && i >= mapped_ents)
 973                         break;
 974
 975                 if (mapped_ents == 0) {
 976                         struct hash_bucket *bucket;
 977                         ref.sg_call_ents = nelems;
 978                         bucket = get_hash_bucket(&ref, &flags);
 979                         entry = hash_bucket_find(bucket, &ref);
 980                         if (entry)
 981                                 mapped_ents = entry->sg_mapped_ents;
 982                         put_hash_bucket(bucket, &flags);
 983                 }
 984
 985                 check_unmap(&ref);
 986         }
 987 }
 988 EXPORT_SYMBOL(debug_dma_unmap_sg);
 989
 990 void debug_dma_alloc_coherent(struct device *dev, size_t size,
 991                               dma_addr_t dma_addr, void *virt)
 992 {
 993         struct dma_debug_entry *entry;
 994
 995         if (unlikely(global_disable))
 996                 return;
 997
 998         if (unlikely(virt == NULL))
 999                 return;
1000
1001         entry = dma_entry_alloc();
1002         if (!entry)
1003                 return;
1004
1005         entry->type      = dma_debug_coherent;
1006         entry->dev       = dev;
1007         entry->paddr     = virt_to_phys(virt);
1008         entry->size      = size;
1009         entry->dev_addr  = dma_addr;
1010         entry->direction = DMA_BIDIRECTIONAL;
1011
1012         add_dma_entry(entry);
1013 }
1014 EXPORT_SYMBOL(debug_dma_alloc_coherent);
1015
1016 void debug_dma_free_coherent(struct device *dev, size_t size,
1017                          void *virt, dma_addr_t addr)
1018 {
1019         struct dma_debug_entry ref = {
1020                 .type           = dma_debug_coherent,
1021                 .dev            = dev,
1022                 .paddr          = virt_to_phys(virt),
1023                 .dev_addr       = addr,
1024                 .size           = size,
1025                 .direction      = DMA_BIDIRECTIONAL,
1026         };
1027
1028         if (unlikely(global_disable))
1029                 return;
1030
1031         check_unmap(&ref);
1032 }
1033 EXPORT_SYMBOL(debug_dma_free_coherent);
1034
1035 void debug_dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_handle,
1036                                    size_t size, int direction)
1037 {
1038         if (unlikely(global_disable))
1039                 return;
1040
1041         check_sync(dev, dma_handle, size, 0, direction, true);
1042 }
1043 EXPORT_SYMBOL(debug_dma_sync_single_for_cpu);
1044
1045 void debug_dma_sync_single_for_device(struct device *dev,
1046                                       dma_addr_t dma_handle, size_t size,
1047                                       int direction)
1048 {
1049         if (unlikely(global_disable))
1050                 return;
1051
1052         check_sync(dev, dma_handle, size, 0, direction, false);
1053 }
1054 EXPORT_SYMBOL(debug_dma_sync_single_for_device);
1055
1056 void debug_dma_sync_single_range_for_cpu(struct device *dev,
1057                                          dma_addr_t dma_handle,
1058                                          unsigned long offset, size_t size,
1059                                          int direction)
1060 {
1061         if (unlikely(global_disable))
1062                 return;
1063
1064         check_sync(dev, dma_handle, size, offset, direction, true);
1065 }
1066 EXPORT_SYMBOL(debug_dma_sync_single_range_for_cpu);
1067
1068 void debug_dma_sync_single_range_for_device(struct device *dev,
1069                                             dma_addr_t dma_handle,
1070                                             unsigned long offset,
1071                                             size_t size, int direction)
1072 {
1073         if (unlikely(global_disable))
1074                 return;
1075
1076         check_sync(dev, dma_handle, size, offset, direction, false);
1077 }
1078 EXPORT_SYMBOL(debug_dma_sync_single_range_for_device);
1079
1080 void debug_dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
1081                                int nelems, int direction)
1082 {
1083         struct scatterlist *s;
1084         int i;
1085
1086         if (unlikely(global_disable))
1087                 return;
1088
1089         for_each_sg(sg, s, nelems, i) {
1090                 check_sync(dev, s->dma_address, s->dma_length, 0,
1091                                 direction, true);
1092         }
1093 }
1094 EXPORT_SYMBOL(debug_dma_sync_sg_for_cpu);
1095
1096 void debug_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
1097                                   int nelems, int direction)
1098 {
1099         struct scatterlist *s;
1100         int i;
1101
1102         if (unlikely(global_disable))
1103                 return;
1104
1105         for_each_sg(sg, s, nelems, i) {
1106                 check_sync(dev, s->dma_address, s->dma_length, 0,
1107                                 direction, false);
1108         }
1109 }
1110 EXPORT_SYMBOL(debug_dma_sync_sg_for_device);
1111
1112 static int __init dma_debug_driver_setup(char *str)
1113 {
1114         int i;
1115
1116         for (i = 0; i < NAME_MAX_LEN - 1; ++i, ++str) {
1117                 current_driver_name[i] = *str;
1118                 if (*str == 0)
1119                         break;
1120         }
1121
1122         if (current_driver_name[0])
1123                 printk(KERN_INFO "DMA-API: enable driver filter for "
1124                                  "driver [%s]\n", current_driver_name);
1125
1126
1127         return 1;
1128 }
1129 __setup("dma_debug_driver=", dma_debug_driver_setup);