Merge branch 'dma-debug/2.6.31' of git://git.kernel.org/pub/scm/linux/kernel/git...
[linux-3.10.git] / 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, *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         /* Now handle the string we got from userspace very carefully.
546          * The rules are:
547          *         - only use the first token we got
548          *         - token delimiter is everything looking like a space
549          *           character (' ', '\n', '\t' ...)
550          *
551          */
552         if (!isalnum(buf[0])) {
553                 /*
554                    If the first character userspace gave us is not
555                  * alphanumerical then assume the filter should be
556                  * switched off.
557                  */
558                 if (current_driver_name[0])
559                         printk(KERN_INFO "DMA-API: switching off dma-debug "
560                                          "driver filter\n");
561                 current_driver_name[0] = 0;
562                 current_driver = NULL;
563                 goto out_unlock;
564         }
565
566         /*
567          * Now parse out the first token and use it as the name for the
568          * driver to filter for.
569          */
570         for (i = 0; i < NAME_MAX_LEN; ++i) {
571                 current_driver_name[i] = buf[i];
572                 if (isspace(buf[i]) || buf[i] == ' ' || buf[i] == 0)
573                         break;
574         }
575         current_driver_name[i] = 0;
576         current_driver = NULL;
577
578         printk(KERN_INFO "DMA-API: enable driver filter for driver [%s]\n",
579                current_driver_name);
580
581 out_unlock:
582         write_unlock_irqrestore(&driver_name_lock, flags);
583
584         return count;
585 }
586
587 const struct file_operations filter_fops = {
588         .read  = filter_read,
589         .write = filter_write,
590 };
591
592 static int dma_debug_fs_init(void)
593 {
594         dma_debug_dent = debugfs_create_dir("dma-api", NULL);
595         if (!dma_debug_dent) {
596                 printk(KERN_ERR "DMA-API: can not create debugfs directory\n");
597                 return -ENOMEM;
598         }
599
600         global_disable_dent = debugfs_create_bool("disabled", 0444,
601                         dma_debug_dent,
602                         (u32 *)&global_disable);
603         if (!global_disable_dent)
604                 goto out_err;
605
606         error_count_dent = debugfs_create_u32("error_count", 0444,
607                         dma_debug_dent, &error_count);
608         if (!error_count_dent)
609                 goto out_err;
610
611         show_all_errors_dent = debugfs_create_u32("all_errors", 0644,
612                         dma_debug_dent,
613                         &show_all_errors);
614         if (!show_all_errors_dent)
615                 goto out_err;
616
617         show_num_errors_dent = debugfs_create_u32("num_errors", 0644,
618                         dma_debug_dent,
619                         &show_num_errors);
620         if (!show_num_errors_dent)
621                 goto out_err;
622
623         num_free_entries_dent = debugfs_create_u32("num_free_entries", 0444,
624                         dma_debug_dent,
625                         &num_free_entries);
626         if (!num_free_entries_dent)
627                 goto out_err;
628
629         min_free_entries_dent = debugfs_create_u32("min_free_entries", 0444,
630                         dma_debug_dent,
631                         &min_free_entries);
632         if (!min_free_entries_dent)
633                 goto out_err;
634
635         filter_dent = debugfs_create_file("driver_filter", 0644,
636                                           dma_debug_dent, NULL, &filter_fops);
637         if (!filter_dent)
638                 goto out_err;
639
640         return 0;
641
642 out_err:
643         debugfs_remove_recursive(dma_debug_dent);
644
645         return -ENOMEM;
646 }
647
648 static int device_dma_allocations(struct device *dev)
649 {
650         struct dma_debug_entry *entry;
651         unsigned long flags;
652         int count = 0, i;
653
654         for (i = 0; i < HASH_SIZE; ++i) {
655                 spin_lock_irqsave(&dma_entry_hash[i].lock, flags);
656                 list_for_each_entry(entry, &dma_entry_hash[i].list, list) {
657                         if (entry->dev == dev)
658                                 count += 1;
659                 }
660                 spin_unlock_irqrestore(&dma_entry_hash[i].lock, flags);
661         }
662
663         return count;
664 }
665
666 static int dma_debug_device_change(struct notifier_block *nb,
667                                     unsigned long action, void *data)
668 {
669         struct device *dev = data;
670         int count;
671
672
673         switch (action) {
674         case BUS_NOTIFY_UNBOUND_DRIVER:
675                 count = device_dma_allocations(dev);
676                 if (count == 0)
677                         break;
678                 err_printk(dev, NULL, "DMA-API: device driver has pending "
679                                 "DMA allocations while released from device "
680                                 "[count=%d]\n", count);
681                 break;
682         default:
683                 break;
684         }
685
686         return 0;
687 }
688
689 void dma_debug_add_bus(struct bus_type *bus)
690 {
691         struct notifier_block *nb;
692
693         nb = kzalloc(sizeof(struct notifier_block), GFP_KERNEL);
694         if (nb == NULL) {
695                 printk(KERN_ERR "dma_debug_add_bus: out of memory\n");
696                 return;
697         }
698
699         nb->notifier_call = dma_debug_device_change;
700
701         bus_register_notifier(bus, nb);
702 }
703
704 /*
705  * Let the architectures decide how many entries should be preallocated.
706  */
707 void dma_debug_init(u32 num_entries)
708 {
709         int i;
710
711         if (global_disable)
712                 return;
713
714         for (i = 0; i < HASH_SIZE; ++i) {
715                 INIT_LIST_HEAD(&dma_entry_hash[i].list);
716                 dma_entry_hash[i].lock = SPIN_LOCK_UNLOCKED;
717         }
718
719         if (dma_debug_fs_init() != 0) {
720                 printk(KERN_ERR "DMA-API: error creating debugfs entries "
721                                 "- disabling\n");
722                 global_disable = true;
723
724                 return;
725         }
726
727         if (req_entries)
728                 num_entries = req_entries;
729
730         if (prealloc_memory(num_entries) != 0) {
731                 printk(KERN_ERR "DMA-API: debugging out of memory error "
732                                 "- disabled\n");
733                 global_disable = true;
734
735                 return;
736         }
737
738         nr_total_entries = num_free_entries;
739
740         printk(KERN_INFO "DMA-API: debugging enabled by kernel config\n");
741 }
742
743 static __init int dma_debug_cmdline(char *str)
744 {
745         if (!str)
746                 return -EINVAL;
747
748         if (strncmp(str, "off", 3) == 0) {
749                 printk(KERN_INFO "DMA-API: debugging disabled on kernel "
750                                  "command line\n");
751                 global_disable = true;
752         }
753
754         return 0;
755 }
756
757 static __init int dma_debug_entries_cmdline(char *str)
758 {
759         int res;
760
761         if (!str)
762                 return -EINVAL;
763
764         res = get_option(&str, &req_entries);
765
766         if (!res)
767                 req_entries = 0;
768
769         return 0;
770 }
771
772 __setup("dma_debug=", dma_debug_cmdline);
773 __setup("dma_debug_entries=", dma_debug_entries_cmdline);
774
775 static void check_unmap(struct dma_debug_entry *ref)
776 {
777         struct dma_debug_entry *entry;
778         struct hash_bucket *bucket;
779         unsigned long flags;
780
781         if (dma_mapping_error(ref->dev, ref->dev_addr)) {
782                 err_printk(ref->dev, NULL, "DMA-API: device driver tries "
783                            "to free an invalid DMA memory address\n");
784                 return;
785         }
786
787         bucket = get_hash_bucket(ref, &flags);
788         entry = hash_bucket_find(bucket, ref);
789
790         if (!entry) {
791                 err_printk(ref->dev, NULL, "DMA-API: device driver tries "
792                            "to free DMA memory it has not allocated "
793                            "[device address=0x%016llx] [size=%llu bytes]\n",
794                            ref->dev_addr, ref->size);
795                 goto out;
796         }
797
798         if (ref->size != entry->size) {
799                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
800                            "DMA memory with different size "
801                            "[device address=0x%016llx] [map size=%llu bytes] "
802                            "[unmap size=%llu bytes]\n",
803                            ref->dev_addr, entry->size, ref->size);
804         }
805
806         if (ref->type != entry->type) {
807                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
808                            "DMA memory with wrong function "
809                            "[device address=0x%016llx] [size=%llu bytes] "
810                            "[mapped as %s] [unmapped as %s]\n",
811                            ref->dev_addr, ref->size,
812                            type2name[entry->type], type2name[ref->type]);
813         } else if ((entry->type == dma_debug_coherent) &&
814                    (ref->paddr != entry->paddr)) {
815                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
816                            "DMA memory with different CPU address "
817                            "[device address=0x%016llx] [size=%llu bytes] "
818                            "[cpu alloc address=%p] [cpu free address=%p]",
819                            ref->dev_addr, ref->size,
820                            (void *)entry->paddr, (void *)ref->paddr);
821         }
822
823         if (ref->sg_call_ents && ref->type == dma_debug_sg &&
824             ref->sg_call_ents != entry->sg_call_ents) {
825                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
826                            "DMA sg list with different entry count "
827                            "[map count=%d] [unmap count=%d]\n",
828                            entry->sg_call_ents, ref->sg_call_ents);
829         }
830
831         /*
832          * This may be no bug in reality - but most implementations of the
833          * DMA API don't handle this properly, so check for it here
834          */
835         if (ref->direction != entry->direction) {
836                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
837                            "DMA memory with different direction "
838                            "[device address=0x%016llx] [size=%llu bytes] "
839                            "[mapped with %s] [unmapped with %s]\n",
840                            ref->dev_addr, ref->size,
841                            dir2name[entry->direction],
842                            dir2name[ref->direction]);
843         }
844
845         hash_bucket_del(entry);
846         dma_entry_free(entry);
847
848 out:
849         put_hash_bucket(bucket, &flags);
850 }
851
852 static void check_for_stack(struct device *dev, void *addr)
853 {
854         if (object_is_on_stack(addr))
855                 err_printk(dev, NULL, "DMA-API: device driver maps memory from"
856                                 "stack [addr=%p]\n", addr);
857 }
858
859 static inline bool overlap(void *addr, u64 size, void *start, void *end)
860 {
861         void *addr2 = (char *)addr + size;
862
863         return ((addr >= start && addr < end) ||
864                 (addr2 >= start && addr2 < end) ||
865                 ((addr < start) && (addr2 >= end)));
866 }
867
868 static void check_for_illegal_area(struct device *dev, void *addr, u64 size)
869 {
870         if (overlap(addr, size, _text, _etext) ||
871             overlap(addr, size, __start_rodata, __end_rodata))
872                 err_printk(dev, NULL, "DMA-API: device driver maps "
873                                 "memory from kernel text or rodata "
874                                 "[addr=%p] [size=%llu]\n", addr, size);
875 }
876
877 static void check_sync(struct device *dev, dma_addr_t addr,
878                        u64 size, u64 offset, int direction, bool to_cpu)
879 {
880         struct dma_debug_entry ref = {
881                 .dev            = dev,
882                 .dev_addr       = addr,
883                 .size           = size,
884                 .direction      = direction,
885         };
886         struct dma_debug_entry *entry;
887         struct hash_bucket *bucket;
888         unsigned long flags;
889
890         bucket = get_hash_bucket(&ref, &flags);
891
892         entry = hash_bucket_find(bucket, &ref);
893
894         if (!entry) {
895                 err_printk(dev, NULL, "DMA-API: device driver tries "
896                                 "to sync DMA memory it has not allocated "
897                                 "[device address=0x%016llx] [size=%llu bytes]\n",
898                                 (unsigned long long)addr, size);
899                 goto out;
900         }
901
902         if ((offset + size) > entry->size) {
903                 err_printk(dev, entry, "DMA-API: device driver syncs"
904                                 " DMA memory outside allocated range "
905                                 "[device address=0x%016llx] "
906                                 "[allocation size=%llu bytes] [sync offset=%llu] "
907                                 "[sync size=%llu]\n", entry->dev_addr, entry->size,
908                                 offset, size);
909         }
910
911         if (direction != entry->direction) {
912                 err_printk(dev, entry, "DMA-API: device driver syncs "
913                                 "DMA memory with different direction "
914                                 "[device address=0x%016llx] [size=%llu bytes] "
915                                 "[mapped with %s] [synced with %s]\n",
916                                 (unsigned long long)addr, entry->size,
917                                 dir2name[entry->direction],
918                                 dir2name[direction]);
919         }
920
921         if (entry->direction == DMA_BIDIRECTIONAL)
922                 goto out;
923
924         if (to_cpu && !(entry->direction == DMA_FROM_DEVICE) &&
925                       !(direction == DMA_TO_DEVICE))
926                 err_printk(dev, entry, "DMA-API: device driver syncs "
927                                 "device read-only DMA memory for cpu "
928                                 "[device address=0x%016llx] [size=%llu bytes] "
929                                 "[mapped with %s] [synced with %s]\n",
930                                 (unsigned long long)addr, entry->size,
931                                 dir2name[entry->direction],
932                                 dir2name[direction]);
933
934         if (!to_cpu && !(entry->direction == DMA_TO_DEVICE) &&
935                        !(direction == DMA_FROM_DEVICE))
936                 err_printk(dev, entry, "DMA-API: device driver syncs "
937                                 "device write-only DMA memory to device "
938                                 "[device address=0x%016llx] [size=%llu bytes] "
939                                 "[mapped with %s] [synced with %s]\n",
940                                 (unsigned long long)addr, entry->size,
941                                 dir2name[entry->direction],
942                                 dir2name[direction]);
943
944 out:
945         put_hash_bucket(bucket, &flags);
946
947 }
948
949 void debug_dma_map_page(struct device *dev, struct page *page, size_t offset,
950                         size_t size, int direction, dma_addr_t dma_addr,
951                         bool map_single)
952 {
953         struct dma_debug_entry *entry;
954
955         if (unlikely(global_disable))
956                 return;
957
958         if (unlikely(dma_mapping_error(dev, dma_addr)))
959                 return;
960
961         entry = dma_entry_alloc();
962         if (!entry)
963                 return;
964
965         entry->dev       = dev;
966         entry->type      = dma_debug_page;
967         entry->paddr     = page_to_phys(page) + offset;
968         entry->dev_addr  = dma_addr;
969         entry->size      = size;
970         entry->direction = direction;
971
972         if (map_single)
973                 entry->type = dma_debug_single;
974
975         if (!PageHighMem(page)) {
976                 void *addr = ((char *)page_address(page)) + offset;
977                 check_for_stack(dev, addr);
978                 check_for_illegal_area(dev, addr, size);
979         }
980
981         add_dma_entry(entry);
982 }
983 EXPORT_SYMBOL(debug_dma_map_page);
984
985 void debug_dma_unmap_page(struct device *dev, dma_addr_t addr,
986                           size_t size, int direction, bool map_single)
987 {
988         struct dma_debug_entry ref = {
989                 .type           = dma_debug_page,
990                 .dev            = dev,
991                 .dev_addr       = addr,
992                 .size           = size,
993                 .direction      = direction,
994         };
995
996         if (unlikely(global_disable))
997                 return;
998
999         if (map_single)
1000                 ref.type = dma_debug_single;
1001
1002         check_unmap(&ref);
1003 }
1004 EXPORT_SYMBOL(debug_dma_unmap_page);
1005
1006 void debug_dma_map_sg(struct device *dev, struct scatterlist *sg,
1007                       int nents, int mapped_ents, int direction)
1008 {
1009         struct dma_debug_entry *entry;
1010         struct scatterlist *s;
1011         int i;
1012
1013         if (unlikely(global_disable))
1014                 return;
1015
1016         for_each_sg(sg, s, mapped_ents, i) {
1017                 entry = dma_entry_alloc();
1018                 if (!entry)
1019                         return;
1020
1021                 entry->type           = dma_debug_sg;
1022                 entry->dev            = dev;
1023                 entry->paddr          = sg_phys(s);
1024                 entry->size           = sg_dma_len(s);
1025                 entry->dev_addr       = sg_dma_address(s);
1026                 entry->direction      = direction;
1027                 entry->sg_call_ents   = nents;
1028                 entry->sg_mapped_ents = mapped_ents;
1029
1030                 if (!PageHighMem(sg_page(s))) {
1031                         check_for_stack(dev, sg_virt(s));
1032                         check_for_illegal_area(dev, sg_virt(s), sg_dma_len(s));
1033                 }
1034
1035                 add_dma_entry(entry);
1036         }
1037 }
1038 EXPORT_SYMBOL(debug_dma_map_sg);
1039
1040 static int get_nr_mapped_entries(struct device *dev, struct scatterlist *s)
1041 {
1042         struct dma_debug_entry *entry;
1043         struct hash_bucket *bucket;
1044         unsigned long flags;
1045         int mapped_ents = 0;
1046         struct dma_debug_entry ref;
1047
1048         ref.dev = dev;
1049         ref.dev_addr = sg_dma_address(s);
1050         ref.size = sg_dma_len(s),
1051
1052         bucket = get_hash_bucket(&ref, &flags);
1053         entry = hash_bucket_find(bucket, &ref);
1054         if (entry)
1055                 mapped_ents = entry->sg_mapped_ents;
1056         put_hash_bucket(bucket, &flags);
1057
1058         return mapped_ents;
1059 }
1060
1061 void debug_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
1062                         int nelems, int dir)
1063 {
1064         struct scatterlist *s;
1065         int mapped_ents = 0, i;
1066
1067         if (unlikely(global_disable))
1068                 return;
1069
1070         for_each_sg(sglist, s, nelems, i) {
1071
1072                 struct dma_debug_entry ref = {
1073                         .type           = dma_debug_sg,
1074                         .dev            = dev,
1075                         .paddr          = sg_phys(s),
1076                         .dev_addr       = sg_dma_address(s),
1077                         .size           = sg_dma_len(s),
1078                         .direction      = dir,
1079                         .sg_call_ents   = 0,
1080                 };
1081
1082                 if (mapped_ents && i >= mapped_ents)
1083                         break;
1084
1085                 if (!i) {
1086                         ref.sg_call_ents = nelems;
1087                         mapped_ents = get_nr_mapped_entries(dev, s);
1088                 }
1089
1090                 check_unmap(&ref);
1091         }
1092 }
1093 EXPORT_SYMBOL(debug_dma_unmap_sg);
1094
1095 void debug_dma_alloc_coherent(struct device *dev, size_t size,
1096                               dma_addr_t dma_addr, void *virt)
1097 {
1098         struct dma_debug_entry *entry;
1099
1100         if (unlikely(global_disable))
1101                 return;
1102
1103         if (unlikely(virt == NULL))
1104                 return;
1105
1106         entry = dma_entry_alloc();
1107         if (!entry)
1108                 return;
1109
1110         entry->type      = dma_debug_coherent;
1111         entry->dev       = dev;
1112         entry->paddr     = virt_to_phys(virt);
1113         entry->size      = size;
1114         entry->dev_addr  = dma_addr;
1115         entry->direction = DMA_BIDIRECTIONAL;
1116
1117         add_dma_entry(entry);
1118 }
1119 EXPORT_SYMBOL(debug_dma_alloc_coherent);
1120
1121 void debug_dma_free_coherent(struct device *dev, size_t size,
1122                          void *virt, dma_addr_t addr)
1123 {
1124         struct dma_debug_entry ref = {
1125                 .type           = dma_debug_coherent,
1126                 .dev            = dev,
1127                 .paddr          = virt_to_phys(virt),
1128                 .dev_addr       = addr,
1129                 .size           = size,
1130                 .direction      = DMA_BIDIRECTIONAL,
1131         };
1132
1133         if (unlikely(global_disable))
1134                 return;
1135
1136         check_unmap(&ref);
1137 }
1138 EXPORT_SYMBOL(debug_dma_free_coherent);
1139
1140 void debug_dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_handle,
1141                                    size_t size, int direction)
1142 {
1143         if (unlikely(global_disable))
1144                 return;
1145
1146         check_sync(dev, dma_handle, size, 0, direction, true);
1147 }
1148 EXPORT_SYMBOL(debug_dma_sync_single_for_cpu);
1149
1150 void debug_dma_sync_single_for_device(struct device *dev,
1151                                       dma_addr_t dma_handle, size_t size,
1152                                       int direction)
1153 {
1154         if (unlikely(global_disable))
1155                 return;
1156
1157         check_sync(dev, dma_handle, size, 0, direction, false);
1158 }
1159 EXPORT_SYMBOL(debug_dma_sync_single_for_device);
1160
1161 void debug_dma_sync_single_range_for_cpu(struct device *dev,
1162                                          dma_addr_t dma_handle,
1163                                          unsigned long offset, size_t size,
1164                                          int direction)
1165 {
1166         if (unlikely(global_disable))
1167                 return;
1168
1169         check_sync(dev, dma_handle, size, offset, direction, true);
1170 }
1171 EXPORT_SYMBOL(debug_dma_sync_single_range_for_cpu);
1172
1173 void debug_dma_sync_single_range_for_device(struct device *dev,
1174                                             dma_addr_t dma_handle,
1175                                             unsigned long offset,
1176                                             size_t size, int direction)
1177 {
1178         if (unlikely(global_disable))
1179                 return;
1180
1181         check_sync(dev, dma_handle, size, offset, direction, false);
1182 }
1183 EXPORT_SYMBOL(debug_dma_sync_single_range_for_device);
1184
1185 void debug_dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
1186                                int nelems, int direction)
1187 {
1188         struct scatterlist *s;
1189         int mapped_ents = 0, i;
1190
1191         if (unlikely(global_disable))
1192                 return;
1193
1194         for_each_sg(sg, s, nelems, i) {
1195                 if (!i)
1196                         mapped_ents = get_nr_mapped_entries(dev, s);
1197
1198                 if (i >= mapped_ents)
1199                         break;
1200
1201                 check_sync(dev, sg_dma_address(s), sg_dma_len(s), 0,
1202                            direction, true);
1203         }
1204 }
1205 EXPORT_SYMBOL(debug_dma_sync_sg_for_cpu);
1206
1207 void debug_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
1208                                   int nelems, int direction)
1209 {
1210         struct scatterlist *s;
1211         int mapped_ents = 0, i;
1212
1213         if (unlikely(global_disable))
1214                 return;
1215
1216         for_each_sg(sg, s, nelems, i) {
1217                 if (!i)
1218                         mapped_ents = get_nr_mapped_entries(dev, s);
1219
1220                 if (i >= mapped_ents)
1221                         break;
1222
1223                 check_sync(dev, sg_dma_address(s), sg_dma_len(s), 0,
1224                            direction, false);
1225         }
1226 }
1227 EXPORT_SYMBOL(debug_dma_sync_sg_for_device);
1228
1229 static int __init dma_debug_driver_setup(char *str)
1230 {
1231         int i;
1232
1233         for (i = 0; i < NAME_MAX_LEN - 1; ++i, ++str) {
1234                 current_driver_name[i] = *str;
1235                 if (*str == 0)
1236                         break;
1237         }
1238
1239         if (current_driver_name[0])
1240                 printk(KERN_INFO "DMA-API: enable driver filter for "
1241                                  "driver [%s]\n", current_driver_name);
1242
1243
1244         return 1;
1245 }
1246 __setup("dma_debug_driver=", dma_debug_driver_setup);