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                 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;
 246
 247         list_for_each_entry(entry, &bucket->list, list) {
 248                 if ((entry->dev_addr == ref->dev_addr) &&
 249                     (entry->dev == ref->dev))
 250                         return entry;
 251         }
 252
 253         return NULL;
 254 }
 255
 256 /*
 257  * Add an entry to a hash bucket
 258  */
 259 static void hash_bucket_add(struct hash_bucket *bucket,
 260                             struct dma_debug_entry *entry)
 261 {
 262         list_add_tail(&entry->list, &bucket->list);
 263 }
 264
 265 /*
 266  * Remove entry from a hash bucket list
 267  */
 268 static void hash_bucket_del(struct dma_debug_entry *entry)
 269 {
 270         list_del(&entry->list);
 271 }
 272
 273 /*
 274  * Dump mapping entries for debugging purposes
 275  */
 276 void debug_dma_dump_mappings(struct device *dev)
 277 {
 278         int idx;
 279
 280         for (idx = 0; idx < HASH_SIZE; idx++) {
 281                 struct hash_bucket *bucket = &dma_entry_hash[idx];
 282                 struct dma_debug_entry *entry;
 283                 unsigned long flags;
 284
 285                 spin_lock_irqsave(&bucket->lock, flags);
 286
 287                 list_for_each_entry(entry, &bucket->list, list) {
 288                         if (!dev || dev == entry->dev) {
 289                                 dev_info(entry->dev,
 290                                          "%s idx %d P=%Lx D=%Lx L=%Lx %s\n",
 291                                          type2name[entry->type], idx,
 292                                          (unsigned long long)entry->paddr,
 293                                          entry->dev_addr, entry->size,
 294                                          dir2name[entry->direction]);
 295                         }
 296                 }
 297
 298                 spin_unlock_irqrestore(&bucket->lock, flags);
 299         }
 300 }
 301 EXPORT_SYMBOL(debug_dma_dump_mappings);
 302
 303 /*
 304  * Wrapper function for adding an entry to the hash.
 305  * This function takes care of locking itself.
 306  */
 307 static void add_dma_entry(struct dma_debug_entry *entry)
 308 {
 309         struct hash_bucket *bucket;
 310         unsigned long flags;
 311
 312         bucket = get_hash_bucket(entry, &flags);
 313         hash_bucket_add(bucket, entry);
 314         put_hash_bucket(bucket, &flags);
 315 }
 316
 317 static struct dma_debug_entry *__dma_entry_alloc(void)
 318 {
 319         struct dma_debug_entry *entry;
 320
 321         entry = list_entry(free_entries.next, struct dma_debug_entry, list);
 322         list_del(&entry->list);
 323         memset(entry, 0, sizeof(*entry));
 324
 325         num_free_entries -= 1;
 326         if (num_free_entries < min_free_entries)
 327                 min_free_entries = num_free_entries;
 328
 329         return entry;
 330 }
 331
 332 /* struct dma_entry allocator
 333  *
 334  * The next two functions implement the allocator for
 335  * struct dma_debug_entries.
 336  */
 337 static struct dma_debug_entry *dma_entry_alloc(void)
 338 {
 339         struct dma_debug_entry *entry = NULL;
 340         unsigned long flags;
 341
 342         spin_lock_irqsave(&free_entries_lock, flags);
 343
 344         if (list_empty(&free_entries)) {
 345                 printk(KERN_ERR "DMA-API: debugging out of memory "
 346                                 "- disabling\n");
 347                 global_disable = true;
 348                 goto out;
 349         }
 350
 351         entry = __dma_entry_alloc();
 352
 353 #ifdef CONFIG_STACKTRACE
 354         entry->stacktrace.max_entries = DMA_DEBUG_STACKTRACE_ENTRIES;
 355         entry->stacktrace.entries = entry->st_entries;
 356         entry->stacktrace.skip = 2;
 357         save_stack_trace(&entry->stacktrace);
 358 #endif
 359
 360 out:
 361         spin_unlock_irqrestore(&free_entries_lock, flags);
 362
 363         return entry;
 364 }
 365
 366 static void dma_entry_free(struct dma_debug_entry *entry)
 367 {
 368         unsigned long flags;
 369
 370         /*
 371          * add to beginning of the list - this way the entries are
 372          * more likely cache hot when they are reallocated.
 373          */
 374         spin_lock_irqsave(&free_entries_lock, flags);
 375         list_add(&entry->list, &free_entries);
 376         num_free_entries += 1;
 377         spin_unlock_irqrestore(&free_entries_lock, flags);
 378 }
 379
 380 int dma_debug_resize_entries(u32 num_entries)
 381 {
 382         int i, delta, ret = 0;
 383         unsigned long flags;
 384         struct dma_debug_entry *entry;
 385         LIST_HEAD(tmp);
 386
 387         spin_lock_irqsave(&free_entries_lock, flags);
 388
 389         if (nr_total_entries < num_entries) {
 390                 delta = num_entries - nr_total_entries;
 391
 392                 spin_unlock_irqrestore(&free_entries_lock, flags);
 393
 394                 for (i = 0; i < delta; i++) {
 395                         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 396                         if (!entry)
 397                                 break;
 398
 399                         list_add_tail(&entry->list, &tmp);
 400                 }
 401
 402                 spin_lock_irqsave(&free_entries_lock, flags);
 403
 404                 list_splice(&tmp, &free_entries);
 405                 nr_total_entries += i;
 406                 num_free_entries += i;
 407         } else {
 408                 delta = nr_total_entries - num_entries;
 409
 410                 for (i = 0; i < delta && !list_empty(&free_entries); i++) {
 411                         entry = __dma_entry_alloc();
 412                         kfree(entry);
 413                 }
 414
 415                 nr_total_entries -= i;
 416         }
 417
 418         if (nr_total_entries != num_entries)
 419                 ret = 1;
 420
 421         spin_unlock_irqrestore(&free_entries_lock, flags);
 422
 423         return ret;
 424 }
 425 EXPORT_SYMBOL(dma_debug_resize_entries);
 426
 427 /*
 428  * DMA-API debugging init code
 429  *
 430  * The init code does two things:
 431  *   1. Initialize core data structures
 432  *   2. Preallocate a given number of dma_debug_entry structs
 433  */
 434
 435 static int prealloc_memory(u32 num_entries)
 436 {
 437         struct dma_debug_entry *entry, *next_entry;
 438         int i;
 439
 440         for (i = 0; i < num_entries; ++i) {
 441                 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
 442                 if (!entry)
 443                         goto out_err;
 444
 445                 list_add_tail(&entry->list, &free_entries);
 446         }
 447
 448         num_free_entries = num_entries;
 449         min_free_entries = num_entries;
 450
 451         printk(KERN_INFO "DMA-API: preallocated %d debug entries\n",
 452                         num_entries);
 453
 454         return 0;
 455
 456 out_err:
 457
 458         list_for_each_entry_safe(entry, next_entry, &free_entries, list) {
 459                 list_del(&entry->list);
 460                 kfree(entry);
 461         }
 462
 463         return -ENOMEM;
 464 }
 465
 466 static ssize_t filter_read(struct file *file, char __user *user_buf,
 467                            size_t count, loff_t *ppos)
 468 {
 469         unsigned long flags;
 470         char buf[NAME_MAX_LEN + 1];
 471         int len;
 472
 473         if (!current_driver_name[0])
 474                 return 0;
 475
 476         /*
 477          * We can't copy to userspace directly because current_driver_name can
 478          * only be read under the driver_name_lock with irqs disabled. So
 479          * create a temporary copy first.
 480          */
 481         read_lock_irqsave(&driver_name_lock, flags);
 482         len = scnprintf(buf, NAME_MAX_LEN + 1, "%s\n", current_driver_name);
 483         read_unlock_irqrestore(&driver_name_lock, flags);
 484
 485         return simple_read_from_buffer(user_buf, count, ppos, buf, len);
 486 }
 487
 488 static ssize_t filter_write(struct file *file, const char __user *userbuf,
 489                             size_t count, loff_t *ppos)
 490 {
 491         unsigned long flags;
 492         char buf[NAME_MAX_LEN];
 493         size_t len = NAME_MAX_LEN - 1;
 494         int i;
 495
 496         /*
 497          * We can't copy from userspace directly. Access to
 498          * current_driver_name is protected with a write_lock with irqs
 499          * disabled. Since copy_from_user can fault and may sleep we
 500          * need to copy to temporary buffer first
 501          */
 502         len = min(count, len);
 503         if (copy_from_user(buf, userbuf, len))
 504                 return -EFAULT;
 505
 506         buf[len] = 0;
 507
 508         write_lock_irqsave(&driver_name_lock, flags);
 509
 510         /* Now handle the string we got from userspace very carefully.
 511          * The rules are:
 512          *         - only use the first token we got
 513          *         - token delimiter is everything looking like a space
 514          *           character (' ', '\n', '\t' ...)
 515          *
 516          */
 517         if (!isalnum(buf[0])) {
 518                 /*
 519                    If the first character userspace gave us is not
 520                  * alphanumerical then assume the filter should be
 521                  * switched off.
 522                  */
 523                 if (current_driver_name[0])
 524                         printk(KERN_INFO "DMA-API: switching off dma-debug "
 525                                          "driver filter\n");
 526                 current_driver_name[0] = 0;
 527                 current_driver = NULL;
 528                 goto out_unlock;
 529         }
 530
 531         /*
 532          * Now parse out the first token and use it as the name for the
 533          * driver to filter for.
 534          */
 535         for (i = 0; i < NAME_MAX_LEN; ++i) {
 536                 current_driver_name[i] = buf[i];
 537                 if (isspace(buf[i]) || buf[i] == ' ' || buf[i] == 0)
 538                         break;
 539         }
 540         current_driver_name[i] = 0;
 541         current_driver = NULL;
 542
 543         printk(KERN_INFO "DMA-API: enable driver filter for driver [%s]\n",
 544                current_driver_name);
 545
 546 out_unlock:
 547         write_unlock_irqrestore(&driver_name_lock, flags);
 548
 549         return count;
 550 }
 551
 552 const struct file_operations filter_fops = {
 553         .read  = filter_read,
 554         .write = filter_write,
 555 };
 556
 557 static int dma_debug_fs_init(void)
 558 {
 559         dma_debug_dent = debugfs_create_dir("dma-api", NULL);
 560         if (!dma_debug_dent) {
 561                 printk(KERN_ERR "DMA-API: can not create debugfs directory\n");
 562                 return -ENOMEM;
 563         }
 564
 565         global_disable_dent = debugfs_create_bool("disabled", 0444,
 566                         dma_debug_dent,
 567                         (u32 *)&global_disable);
 568         if (!global_disable_dent)
 569                 goto out_err;
 570
 571         error_count_dent = debugfs_create_u32("error_count", 0444,
 572                         dma_debug_dent, &error_count);
 573         if (!error_count_dent)
 574                 goto out_err;
 575
 576         show_all_errors_dent = debugfs_create_u32("all_errors", 0644,
 577                         dma_debug_dent,
 578                         &show_all_errors);
 579         if (!show_all_errors_dent)
 580                 goto out_err;
 581
 582         show_num_errors_dent = debugfs_create_u32("num_errors", 0644,
 583                         dma_debug_dent,
 584                         &show_num_errors);
 585         if (!show_num_errors_dent)
 586                 goto out_err;
 587
 588         num_free_entries_dent = debugfs_create_u32("num_free_entries", 0444,
 589                         dma_debug_dent,
 590                         &num_free_entries);
 591         if (!num_free_entries_dent)
 592                 goto out_err;
 593
 594         min_free_entries_dent = debugfs_create_u32("min_free_entries", 0444,
 595                         dma_debug_dent,
 596                         &min_free_entries);
 597         if (!min_free_entries_dent)
 598                 goto out_err;
 599
 600         filter_dent = debugfs_create_file("driver_filter", 0644,
 601                                           dma_debug_dent, NULL, &filter_fops);
 602         if (!filter_dent)
 603                 goto out_err;
 604
 605         return 0;
 606
 607 out_err:
 608         debugfs_remove_recursive(dma_debug_dent);
 609
 610         return -ENOMEM;
 611 }
 612
 613 static int device_dma_allocations(struct device *dev)
 614 {
 615         struct dma_debug_entry *entry;
 616         unsigned long flags;
 617         int count = 0, i;
 618
 619         for (i = 0; i < HASH_SIZE; ++i) {
 620                 spin_lock_irqsave(&dma_entry_hash[i].lock, flags);
 621                 list_for_each_entry(entry, &dma_entry_hash[i].list, list) {
 622                         if (entry->dev == dev)
 623                                 count += 1;
 624                 }
 625                 spin_unlock_irqrestore(&dma_entry_hash[i].lock, flags);
 626         }
 627
 628         return count;
 629 }
 630
 631 static int dma_debug_device_change(struct notifier_block *nb,
 632                                     unsigned long action, void *data)
 633 {
 634         struct device *dev = data;
 635         int count;
 636
 637
 638         switch (action) {
 639         case BUS_NOTIFY_UNBOUND_DRIVER:
 640                 count = device_dma_allocations(dev);
 641                 if (count == 0)
 642                         break;
 643                 err_printk(dev, NULL, "DMA-API: device driver has pending "
 644                                 "DMA allocations while released from device "
 645                                 "[count=%d]\n", count);
 646                 break;
 647         default:
 648                 break;
 649         }
 650
 651         return 0;
 652 }
 653
 654 void dma_debug_add_bus(struct bus_type *bus)
 655 {
 656         struct notifier_block *nb;
 657
 658         nb = kzalloc(sizeof(struct notifier_block), GFP_KERNEL);
 659         if (nb == NULL) {
 660                 printk(KERN_ERR "dma_debug_add_bus: out of memory\n");
 661                 return;
 662         }
 663
 664         nb->notifier_call = dma_debug_device_change;
 665
 666         bus_register_notifier(bus, nb);
 667 }
 668
 669 /*
 670  * Let the architectures decide how many entries should be preallocated.
 671  */
 672 void dma_debug_init(u32 num_entries)
 673 {
 674         int i;
 675
 676         if (global_disable)
 677                 return;
 678
 679         for (i = 0; i < HASH_SIZE; ++i) {
 680                 INIT_LIST_HEAD(&dma_entry_hash[i].list);
 681                 dma_entry_hash[i].lock = SPIN_LOCK_UNLOCKED;
 682         }
 683
 684         if (dma_debug_fs_init() != 0) {
 685                 printk(KERN_ERR "DMA-API: error creating debugfs entries "
 686                                 "- disabling\n");
 687                 global_disable = true;
 688
 689                 return;
 690         }
 691
 692         if (req_entries)
 693                 num_entries = req_entries;
 694
 695         if (prealloc_memory(num_entries) != 0) {
 696                 printk(KERN_ERR "DMA-API: debugging out of memory error "
 697                                 "- disabled\n");
 698                 global_disable = true;
 699
 700                 return;
 701         }
 702
 703         nr_total_entries = num_free_entries;
 704
 705         printk(KERN_INFO "DMA-API: debugging enabled by kernel config\n");
 706 }
 707
 708 static __init int dma_debug_cmdline(char *str)
 709 {
 710         if (!str)
 711                 return -EINVAL;
 712
 713         if (strncmp(str, "off", 3) == 0) {
 714                 printk(KERN_INFO "DMA-API: debugging disabled on kernel "
 715                                  "command line\n");
 716                 global_disable = true;
 717         }
 718
 719         return 0;
 720 }
 721
 722 static __init int dma_debug_entries_cmdline(char *str)
 723 {
 724         int res;
 725
 726         if (!str)
 727                 return -EINVAL;
 728
 729         res = get_option(&str, &req_entries);
 730
 731         if (!res)
 732                 req_entries = 0;
 733
 734         return 0;
 735 }
 736
 737 __setup("dma_debug=", dma_debug_cmdline);
 738 __setup("dma_debug_entries=", dma_debug_entries_cmdline);
 739
 740 static void check_unmap(struct dma_debug_entry *ref)
 741 {
 742         struct dma_debug_entry *entry;
 743         struct hash_bucket *bucket;
 744         unsigned long flags;
 745
 746         if (dma_mapping_error(ref->dev, ref->dev_addr)) {
 747                 err_printk(ref->dev, NULL, "DMA-API: device driver tries "
 748                            "to free an invalid DMA memory address\n");
 749                 return;
 750         }
 751
 752         bucket = get_hash_bucket(ref, &flags);
 753         entry = hash_bucket_find(bucket, ref);
 754
 755         if (!entry) {
 756                 err_printk(ref->dev, NULL, "DMA-API: device driver tries "
 757                            "to free DMA memory it has not allocated "
 758                            "[device address=0x%016llx] [size=%llu bytes]\n",
 759                            ref->dev_addr, ref->size);
 760                 goto out;
 761         }
 762
 763         if (ref->size != entry->size) {
 764                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
 765                            "DMA memory with different size "
 766                            "[device address=0x%016llx] [map size=%llu bytes] "
 767                            "[unmap size=%llu bytes]\n",
 768                            ref->dev_addr, entry->size, ref->size);
 769         }
 770
 771         if (ref->type != entry->type) {
 772                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
 773                            "DMA memory with wrong function "
 774                            "[device address=0x%016llx] [size=%llu bytes] "
 775                            "[mapped as %s] [unmapped as %s]\n",
 776                            ref->dev_addr, ref->size,
 777                            type2name[entry->type], type2name[ref->type]);
 778         } else if ((entry->type == dma_debug_coherent) &&
 779                    (ref->paddr != entry->paddr)) {
 780                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
 781                            "DMA memory with different CPU address "
 782                            "[device address=0x%016llx] [size=%llu bytes] "
 783                            "[cpu alloc address=%p] [cpu free address=%p]",
 784                            ref->dev_addr, ref->size,
 785                            (void *)entry->paddr, (void *)ref->paddr);
 786         }
 787
 788         if (ref->sg_call_ents && ref->type == dma_debug_sg &&
 789             ref->sg_call_ents != entry->sg_call_ents) {
 790                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
 791                            "DMA sg list with different entry count "
 792                            "[map count=%d] [unmap count=%d]\n",
 793                            entry->sg_call_ents, ref->sg_call_ents);
 794         }
 795
 796         /*
 797          * This may be no bug in reality - but most implementations of the
 798          * DMA API don't handle this properly, so check for it here
 799          */
 800         if (ref->direction != entry->direction) {
 801                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
 802                            "DMA memory with different direction "
 803                            "[device address=0x%016llx] [size=%llu bytes] "
 804                            "[mapped with %s] [unmapped with %s]\n",
 805                            ref->dev_addr, ref->size,
 806                            dir2name[entry->direction],
 807                            dir2name[ref->direction]);
 808         }
 809
 810         hash_bucket_del(entry);
 811         dma_entry_free(entry);
 812
 813 out:
 814         put_hash_bucket(bucket, &flags);
 815 }
 816
 817 static void check_for_stack(struct device *dev, void *addr)
 818 {
 819         if (object_is_on_stack(addr))
 820                 err_printk(dev, NULL, "DMA-API: device driver maps memory from"
 821                                 "stack [addr=%p]\n", addr);
 822 }
 823
 824 static inline bool overlap(void *addr, u64 size, void *start, void *end)
 825 {
 826         void *addr2 = (char *)addr + size;
 827
 828         return ((addr >= start && addr < end) ||
 829                 (addr2 >= start && addr2 < end) ||
 830                 ((addr < start) && (addr2 >= end)));
 831 }
 832
 833 static void check_for_illegal_area(struct device *dev, void *addr, u64 size)
 834 {
 835         if (overlap(addr, size, _text, _etext) ||
 836             overlap(addr, size, __start_rodata, __end_rodata))
 837                 err_printk(dev, NULL, "DMA-API: device driver maps "
 838                                 "memory from kernel text or rodata "
 839                                 "[addr=%p] [size=%llu]\n", addr, size);
 840 }
 841
 842 static void check_sync(struct device *dev, dma_addr_t addr,
 843                        u64 size, u64 offset, int direction, bool to_cpu)
 844 {
 845         struct dma_debug_entry ref = {
 846                 .dev            = dev,
 847                 .dev_addr       = addr,
 848                 .size           = size,
 849                 .direction      = direction,
 850         };
 851         struct dma_debug_entry *entry;
 852         struct hash_bucket *bucket;
 853         unsigned long flags;
 854
 855         bucket = get_hash_bucket(&ref, &flags);
 856
 857         entry = hash_bucket_find(bucket, &ref);
 858
 859         if (!entry) {
 860                 err_printk(dev, NULL, "DMA-API: device driver tries "
 861                                 "to sync DMA memory it has not allocated "
 862                                 "[device address=0x%016llx] [size=%llu bytes]\n",
 863                                 (unsigned long long)addr, size);
 864                 goto out;
 865         }
 866
 867         if ((offset + size) > entry->size) {
 868                 err_printk(dev, entry, "DMA-API: device driver syncs"
 869                                 " DMA memory outside allocated range "
 870                                 "[device address=0x%016llx] "
 871                                 "[allocation size=%llu bytes] [sync offset=%llu] "
 872                                 "[sync size=%llu]\n", entry->dev_addr, entry->size,
 873                                 offset, size);
 874         }
 875
 876         if (direction != entry->direction) {
 877                 err_printk(dev, entry, "DMA-API: device driver syncs "
 878                                 "DMA memory with different direction "
 879                                 "[device address=0x%016llx] [size=%llu bytes] "
 880                                 "[mapped with %s] [synced with %s]\n",
 881                                 (unsigned long long)addr, entry->size,
 882                                 dir2name[entry->direction],
 883                                 dir2name[direction]);
 884         }
 885
 886         if (entry->direction == DMA_BIDIRECTIONAL)
 887                 goto out;
 888
 889         if (to_cpu && !(entry->direction == DMA_FROM_DEVICE) &&
 890                       !(direction == DMA_TO_DEVICE))
 891                 err_printk(dev, entry, "DMA-API: device driver syncs "
 892                                 "device read-only DMA memory for cpu "
 893                                 "[device address=0x%016llx] [size=%llu bytes] "
 894                                 "[mapped with %s] [synced with %s]\n",
 895                                 (unsigned long long)addr, entry->size,
 896                                 dir2name[entry->direction],
 897                                 dir2name[direction]);
 898
 899         if (!to_cpu && !(entry->direction == DMA_TO_DEVICE) &&
 900                        !(direction == DMA_FROM_DEVICE))
 901                 err_printk(dev, entry, "DMA-API: device driver syncs "
 902                                 "device write-only DMA memory to device "
 903                                 "[device address=0x%016llx] [size=%llu bytes] "
 904                                 "[mapped with %s] [synced with %s]\n",
 905                                 (unsigned long long)addr, entry->size,
 906                                 dir2name[entry->direction],
 907                                 dir2name[direction]);
 908
 909 out:
 910         put_hash_bucket(bucket, &flags);
 911
 912 }
 913
 914 void debug_dma_map_page(struct device *dev, struct page *page, size_t offset,
 915                         size_t size, int direction, dma_addr_t dma_addr,
 916                         bool map_single)
 917 {
 918         struct dma_debug_entry *entry;
 919
 920         if (unlikely(global_disable))
 921                 return;
 922
 923         if (unlikely(dma_mapping_error(dev, dma_addr)))
 924                 return;
 925
 926         entry = dma_entry_alloc();
 927         if (!entry)
 928                 return;
 929
 930         entry->dev       = dev;
 931         entry->type      = dma_debug_page;
 932         entry->paddr     = page_to_phys(page) + offset;
 933         entry->dev_addr  = dma_addr;
 934         entry->size      = size;
 935         entry->direction = direction;
 936
 937         if (map_single)
 938                 entry->type = dma_debug_single;
 939
 940         if (!PageHighMem(page)) {
 941                 void *addr = ((char *)page_address(page)) + offset;
 942                 check_for_stack(dev, addr);
 943                 check_for_illegal_area(dev, addr, size);
 944         }
 945
 946         add_dma_entry(entry);
 947 }
 948 EXPORT_SYMBOL(debug_dma_map_page);
 949
 950 void debug_dma_unmap_page(struct device *dev, dma_addr_t addr,
 951                           size_t size, int direction, bool map_single)
 952 {
 953         struct dma_debug_entry ref = {
 954                 .type           = dma_debug_page,
 955                 .dev            = dev,
 956                 .dev_addr       = addr,
 957                 .size           = size,
 958                 .direction      = direction,
 959         };
 960
 961         if (unlikely(global_disable))
 962                 return;
 963
 964         if (map_single)
 965                 ref.type = dma_debug_single;
 966
 967         check_unmap(&ref);
 968 }
 969 EXPORT_SYMBOL(debug_dma_unmap_page);
 970
 971 void debug_dma_map_sg(struct device *dev, struct scatterlist *sg,
 972                       int nents, int mapped_ents, int direction)
 973 {
 974         struct dma_debug_entry *entry;
 975         struct scatterlist *s;
 976         int i;
 977
 978         if (unlikely(global_disable))
 979                 return;
 980
 981         for_each_sg(sg, s, mapped_ents, i) {
 982                 entry = dma_entry_alloc();
 983                 if (!entry)
 984                         return;
 985
 986                 entry->type           = dma_debug_sg;
 987                 entry->dev            = dev;
 988                 entry->paddr          = sg_phys(s);
 989                 entry->size           = sg_dma_len(s);
 990                 entry->dev_addr       = sg_dma_address(s);
 991                 entry->direction      = direction;
 992                 entry->sg_call_ents   = nents;
 993                 entry->sg_mapped_ents = mapped_ents;
 994
 995                 if (!PageHighMem(sg_page(s))) {
 996                         check_for_stack(dev, sg_virt(s));
 997                         check_for_illegal_area(dev, sg_virt(s), sg_dma_len(s));
 998                 }
 999
1000                 add_dma_entry(entry);
1001         }
1002 }
1003 EXPORT_SYMBOL(debug_dma_map_sg);
1004
1005 static int get_nr_mapped_entries(struct device *dev, struct scatterlist *s)
1006 {
1007         struct dma_debug_entry *entry;
1008         struct hash_bucket *bucket;
1009         unsigned long flags;
1010         int mapped_ents = 0;
1011         struct dma_debug_entry ref;
1012
1013         ref.dev = dev;
1014         ref.dev_addr = sg_dma_address(s);
1015         ref.size = sg_dma_len(s),
1016
1017         bucket = get_hash_bucket(&ref, &flags);
1018         entry = hash_bucket_find(bucket, &ref);
1019         if (entry)
1020                 mapped_ents = entry->sg_mapped_ents;
1021         put_hash_bucket(bucket, &flags);
1022
1023         return mapped_ents;
1024 }
1025
1026 void debug_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
1027                         int nelems, int dir)
1028 {
1029         struct scatterlist *s;
1030         int mapped_ents = 0, i;
1031
1032         if (unlikely(global_disable))
1033                 return;
1034
1035         for_each_sg(sglist, s, nelems, i) {
1036
1037                 struct dma_debug_entry ref = {
1038                         .type           = dma_debug_sg,
1039                         .dev            = dev,
1040                         .paddr          = sg_phys(s),
1041                         .dev_addr       = sg_dma_address(s),
1042                         .size           = sg_dma_len(s),
1043                         .direction      = dir,
1044                         .sg_call_ents   = 0,
1045                 };
1046
1047                 if (mapped_ents && i >= mapped_ents)
1048                         break;
1049
1050                 if (!i) {
1051                         ref.sg_call_ents = nelems;
1052                         mapped_ents = get_nr_mapped_entries(dev, s);
1053                 }
1054
1055                 check_unmap(&ref);
1056         }
1057 }
1058 EXPORT_SYMBOL(debug_dma_unmap_sg);
1059
1060 void debug_dma_alloc_coherent(struct device *dev, size_t size,
1061                               dma_addr_t dma_addr, void *virt)
1062 {
1063         struct dma_debug_entry *entry;
1064
1065         if (unlikely(global_disable))
1066                 return;
1067
1068         if (unlikely(virt == NULL))
1069                 return;
1070
1071         entry = dma_entry_alloc();
1072         if (!entry)
1073                 return;
1074
1075         entry->type      = dma_debug_coherent;
1076         entry->dev       = dev;
1077         entry->paddr     = virt_to_phys(virt);
1078         entry->size      = size;
1079         entry->dev_addr  = dma_addr;
1080         entry->direction = DMA_BIDIRECTIONAL;
1081
1082         add_dma_entry(entry);
1083 }
1084 EXPORT_SYMBOL(debug_dma_alloc_coherent);
1085
1086 void debug_dma_free_coherent(struct device *dev, size_t size,
1087                          void *virt, dma_addr_t addr)
1088 {
1089         struct dma_debug_entry ref = {
1090                 .type           = dma_debug_coherent,
1091                 .dev            = dev,
1092                 .paddr          = virt_to_phys(virt),
1093                 .dev_addr       = addr,
1094                 .size           = size,
1095                 .direction      = DMA_BIDIRECTIONAL,
1096         };
1097
1098         if (unlikely(global_disable))
1099                 return;
1100
1101         check_unmap(&ref);
1102 }
1103 EXPORT_SYMBOL(debug_dma_free_coherent);
1104
1105 void debug_dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_handle,
1106                                    size_t size, int direction)
1107 {
1108         if (unlikely(global_disable))
1109                 return;
1110
1111         check_sync(dev, dma_handle, size, 0, direction, true);
1112 }
1113 EXPORT_SYMBOL(debug_dma_sync_single_for_cpu);
1114
1115 void debug_dma_sync_single_for_device(struct device *dev,
1116                                       dma_addr_t dma_handle, size_t size,
1117                                       int direction)
1118 {
1119         if (unlikely(global_disable))
1120                 return;
1121
1122         check_sync(dev, dma_handle, size, 0, direction, false);
1123 }
1124 EXPORT_SYMBOL(debug_dma_sync_single_for_device);
1125
1126 void debug_dma_sync_single_range_for_cpu(struct device *dev,
1127                                          dma_addr_t dma_handle,
1128                                          unsigned long offset, size_t size,
1129                                          int direction)
1130 {
1131         if (unlikely(global_disable))
1132                 return;
1133
1134         check_sync(dev, dma_handle, size, offset, direction, true);
1135 }
1136 EXPORT_SYMBOL(debug_dma_sync_single_range_for_cpu);
1137
1138 void debug_dma_sync_single_range_for_device(struct device *dev,
1139                                             dma_addr_t dma_handle,
1140                                             unsigned long offset,
1141                                             size_t size, int direction)
1142 {
1143         if (unlikely(global_disable))
1144                 return;
1145
1146         check_sync(dev, dma_handle, size, offset, direction, false);
1147 }
1148 EXPORT_SYMBOL(debug_dma_sync_single_range_for_device);
1149
1150 void debug_dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
1151                                int nelems, int direction)
1152 {
1153         struct scatterlist *s;
1154         int mapped_ents = 0, i;
1155
1156         if (unlikely(global_disable))
1157                 return;
1158
1159         for_each_sg(sg, s, nelems, i) {
1160                 if (!i)
1161                         mapped_ents = get_nr_mapped_entries(dev, s);
1162
1163                 if (i >= mapped_ents)
1164                         break;
1165
1166                 check_sync(dev, sg_dma_address(s), sg_dma_len(s), 0,
1167                            direction, true);
1168         }
1169 }
1170 EXPORT_SYMBOL(debug_dma_sync_sg_for_cpu);
1171
1172 void debug_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
1173                                   int nelems, int direction)
1174 {
1175         struct scatterlist *s;
1176         int mapped_ents = 0, i;
1177
1178         if (unlikely(global_disable))
1179                 return;
1180
1181         for_each_sg(sg, s, nelems, i) {
1182                 if (!i)
1183                         mapped_ents = get_nr_mapped_entries(dev, s);
1184
1185                 if (i >= mapped_ents)
1186                         break;
1187
1188                 check_sync(dev, sg_dma_address(s), sg_dma_len(s), 0,
1189                            direction, false);
1190         }
1191 }
1192 EXPORT_SYMBOL(debug_dma_sync_sg_for_device);
1193
1194 static int __init dma_debug_driver_setup(char *str)
1195 {
1196         int i;
1197
1198         for (i = 0; i < NAME_MAX_LEN - 1; ++i, ++str) {
1199                 current_driver_name[i] = *str;
1200                 if (*str == 0)
1201                         break;
1202         }
1203
1204         if (current_driver_name[0])
1205                 printk(KERN_INFO "DMA-API: enable driver filter for "
1206                                  "driver [%s]\n", current_driver_name);
1207
1208
1209         return 1;
1210 }
1211 __setup("dma_debug_driver=", dma_debug_driver_setup);