dma-debug: comment style fixes
[linux-2.6.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         /*
546          * Now handle the string we got from userspace very carefully.
547          * The rules are:
548          *         - only use the first token we got
549          *         - token delimiter is everything looking like a space
550          *           character (' ', '\n', '\t' ...)
551          *
552          */
553         if (!isalnum(buf[0])) {
554                 /*
555                  * If the first character userspace gave us is not
556                  * alphanumerical then assume the filter should be
557                  * switched off.
558                  */
559                 if (current_driver_name[0])
560                         printk(KERN_INFO "DMA-API: switching off dma-debug "
561                                          "driver filter\n");
562                 current_driver_name[0] = 0;
563                 current_driver = NULL;
564                 goto out_unlock;
565         }
566
567         /*
568          * Now parse out the first token and use it as the name for the
569          * driver to filter for.
570          */
571         for (i = 0; i < NAME_MAX_LEN; ++i) {
572                 current_driver_name[i] = buf[i];
573                 if (isspace(buf[i]) || buf[i] == ' ' || buf[i] == 0)
574                         break;
575         }
576         current_driver_name[i] = 0;
577         current_driver = NULL;
578
579         printk(KERN_INFO "DMA-API: enable driver filter for driver [%s]\n",
580                current_driver_name);
581
582 out_unlock:
583         write_unlock_irqrestore(&driver_name_lock, flags);
584
585         return count;
586 }
587
588 const struct file_operations filter_fops = {
589         .read  = filter_read,
590         .write = filter_write,
591 };
592
593 static int dma_debug_fs_init(void)
594 {
595         dma_debug_dent = debugfs_create_dir("dma-api", NULL);
596         if (!dma_debug_dent) {
597                 printk(KERN_ERR "DMA-API: can not create debugfs directory\n");
598                 return -ENOMEM;
599         }
600
601         global_disable_dent = debugfs_create_bool("disabled", 0444,
602                         dma_debug_dent,
603                         (u32 *)&global_disable);
604         if (!global_disable_dent)
605                 goto out_err;
606
607         error_count_dent = debugfs_create_u32("error_count", 0444,
608                         dma_debug_dent, &error_count);
609         if (!error_count_dent)
610                 goto out_err;
611
612         show_all_errors_dent = debugfs_create_u32("all_errors", 0644,
613                         dma_debug_dent,
614                         &show_all_errors);
615         if (!show_all_errors_dent)
616                 goto out_err;
617
618         show_num_errors_dent = debugfs_create_u32("num_errors", 0644,
619                         dma_debug_dent,
620                         &show_num_errors);
621         if (!show_num_errors_dent)
622                 goto out_err;
623
624         num_free_entries_dent = debugfs_create_u32("num_free_entries", 0444,
625                         dma_debug_dent,
626                         &num_free_entries);
627         if (!num_free_entries_dent)
628                 goto out_err;
629
630         min_free_entries_dent = debugfs_create_u32("min_free_entries", 0444,
631                         dma_debug_dent,
632                         &min_free_entries);
633         if (!min_free_entries_dent)
634                 goto out_err;
635
636         filter_dent = debugfs_create_file("driver_filter", 0644,
637                                           dma_debug_dent, NULL, &filter_fops);
638         if (!filter_dent)
639                 goto out_err;
640
641         return 0;
642
643 out_err:
644         debugfs_remove_recursive(dma_debug_dent);
645
646         return -ENOMEM;
647 }
648
649 static int device_dma_allocations(struct device *dev)
650 {
651         struct dma_debug_entry *entry;
652         unsigned long flags;
653         int count = 0, i;
654
655         for (i = 0; i < HASH_SIZE; ++i) {
656                 spin_lock_irqsave(&dma_entry_hash[i].lock, flags);
657                 list_for_each_entry(entry, &dma_entry_hash[i].list, list) {
658                         if (entry->dev == dev)
659                                 count += 1;
660                 }
661                 spin_unlock_irqrestore(&dma_entry_hash[i].lock, flags);
662         }
663
664         return count;
665 }
666
667 static int dma_debug_device_change(struct notifier_block *nb,
668                                     unsigned long action, void *data)
669 {
670         struct device *dev = data;
671         int count;
672
673
674         switch (action) {
675         case BUS_NOTIFY_UNBOUND_DRIVER:
676                 count = device_dma_allocations(dev);
677                 if (count == 0)
678                         break;
679                 err_printk(dev, NULL, "DMA-API: device driver has pending "
680                                 "DMA allocations while released from device "
681                                 "[count=%d]\n", count);
682                 break;
683         default:
684                 break;
685         }
686
687         return 0;
688 }
689
690 void dma_debug_add_bus(struct bus_type *bus)
691 {
692         struct notifier_block *nb;
693
694         nb = kzalloc(sizeof(struct notifier_block), GFP_KERNEL);
695         if (nb == NULL) {
696                 printk(KERN_ERR "dma_debug_add_bus: out of memory\n");
697                 return;
698         }
699
700         nb->notifier_call = dma_debug_device_change;
701
702         bus_register_notifier(bus, nb);
703 }
704
705 /*
706  * Let the architectures decide how many entries should be preallocated.
707  */
708 void dma_debug_init(u32 num_entries)
709 {
710         int i;
711
712         if (global_disable)
713                 return;
714
715         for (i = 0; i < HASH_SIZE; ++i) {
716                 INIT_LIST_HEAD(&dma_entry_hash[i].list);
717                 dma_entry_hash[i].lock = SPIN_LOCK_UNLOCKED;
718         }
719
720         if (dma_debug_fs_init() != 0) {
721                 printk(KERN_ERR "DMA-API: error creating debugfs entries "
722                                 "- disabling\n");
723                 global_disable = true;
724
725                 return;
726         }
727
728         if (req_entries)
729                 num_entries = req_entries;
730
731         if (prealloc_memory(num_entries) != 0) {
732                 printk(KERN_ERR "DMA-API: debugging out of memory error "
733                                 "- disabled\n");
734                 global_disable = true;
735
736                 return;
737         }
738
739         nr_total_entries = num_free_entries;
740
741         printk(KERN_INFO "DMA-API: debugging enabled by kernel config\n");
742 }
743
744 static __init int dma_debug_cmdline(char *str)
745 {
746         if (!str)
747                 return -EINVAL;
748
749         if (strncmp(str, "off", 3) == 0) {
750                 printk(KERN_INFO "DMA-API: debugging disabled on kernel "
751                                  "command line\n");
752                 global_disable = true;
753         }
754
755         return 0;
756 }
757
758 static __init int dma_debug_entries_cmdline(char *str)
759 {
760         int res;
761
762         if (!str)
763                 return -EINVAL;
764
765         res = get_option(&str, &req_entries);
766
767         if (!res)
768                 req_entries = 0;
769
770         return 0;
771 }
772
773 __setup("dma_debug=", dma_debug_cmdline);
774 __setup("dma_debug_entries=", dma_debug_entries_cmdline);
775
776 static void check_unmap(struct dma_debug_entry *ref)
777 {
778         struct dma_debug_entry *entry;
779         struct hash_bucket *bucket;
780         unsigned long flags;
781
782         if (dma_mapping_error(ref->dev, ref->dev_addr)) {
783                 err_printk(ref->dev, NULL, "DMA-API: device driver tries "
784                            "to free an invalid DMA memory address\n");
785                 return;
786         }
787
788         bucket = get_hash_bucket(ref, &flags);
789         entry = hash_bucket_find(bucket, ref);
790
791         if (!entry) {
792                 err_printk(ref->dev, NULL, "DMA-API: device driver tries "
793                            "to free DMA memory it has not allocated "
794                            "[device address=0x%016llx] [size=%llu bytes]\n",
795                            ref->dev_addr, ref->size);
796                 goto out;
797         }
798
799         if (ref->size != entry->size) {
800                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
801                            "DMA memory with different size "
802                            "[device address=0x%016llx] [map size=%llu bytes] "
803                            "[unmap size=%llu bytes]\n",
804                            ref->dev_addr, entry->size, ref->size);
805         }
806
807         if (ref->type != entry->type) {
808                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
809                            "DMA memory with wrong function "
810                            "[device address=0x%016llx] [size=%llu bytes] "
811                            "[mapped as %s] [unmapped as %s]\n",
812                            ref->dev_addr, ref->size,
813                            type2name[entry->type], type2name[ref->type]);
814         } else if ((entry->type == dma_debug_coherent) &&
815                    (ref->paddr != entry->paddr)) {
816                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
817                            "DMA memory with different CPU address "
818                            "[device address=0x%016llx] [size=%llu bytes] "
819                            "[cpu alloc address=%p] [cpu free address=%p]",
820                            ref->dev_addr, ref->size,
821                            (void *)entry->paddr, (void *)ref->paddr);
822         }
823
824         if (ref->sg_call_ents && ref->type == dma_debug_sg &&
825             ref->sg_call_ents != entry->sg_call_ents) {
826                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
827                            "DMA sg list with different entry count "
828                            "[map count=%d] [unmap count=%d]\n",
829                            entry->sg_call_ents, ref->sg_call_ents);
830         }
831
832         /*
833          * This may be no bug in reality - but most implementations of the
834          * DMA API don't handle this properly, so check for it here
835          */
836         if (ref->direction != entry->direction) {
837                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
838                            "DMA memory with different direction "
839                            "[device address=0x%016llx] [size=%llu bytes] "
840                            "[mapped with %s] [unmapped with %s]\n",
841                            ref->dev_addr, ref->size,
842                            dir2name[entry->direction],
843                            dir2name[ref->direction]);
844         }
845
846         hash_bucket_del(entry);
847         dma_entry_free(entry);
848
849 out:
850         put_hash_bucket(bucket, &flags);
851 }
852
853 static void check_for_stack(struct device *dev, void *addr)
854 {
855         if (object_is_on_stack(addr))
856                 err_printk(dev, NULL, "DMA-API: device driver maps memory from"
857                                 "stack [addr=%p]\n", addr);
858 }
859
860 static inline bool overlap(void *addr, u64 size, void *start, void *end)
861 {
862         void *addr2 = (char *)addr + size;
863
864         return ((addr >= start && addr < end) ||
865                 (addr2 >= start && addr2 < end) ||
866                 ((addr < start) && (addr2 >= end)));
867 }
868
869 static void check_for_illegal_area(struct device *dev, void *addr, u64 size)
870 {
871         if (overlap(addr, size, _text, _etext) ||
872             overlap(addr, size, __start_rodata, __end_rodata))
873                 err_printk(dev, NULL, "DMA-API: device driver maps "
874                                 "memory from kernel text or rodata "
875                                 "[addr=%p] [size=%llu]\n", addr, size);
876 }
877
878 static void check_sync(struct device *dev, dma_addr_t addr,
879                        u64 size, u64 offset, int direction, bool to_cpu)
880 {
881         struct dma_debug_entry ref = {
882                 .dev            = dev,
883                 .dev_addr       = addr,
884                 .size           = size,
885                 .direction      = direction,
886         };
887         struct dma_debug_entry *entry;
888         struct hash_bucket *bucket;
889         unsigned long flags;
890
891         bucket = get_hash_bucket(&ref, &flags);
892
893         entry = hash_bucket_find(bucket, &ref);
894
895         if (!entry) {
896                 err_printk(dev, NULL, "DMA-API: device driver tries "
897                                 "to sync DMA memory it has not allocated "
898                                 "[device address=0x%016llx] [size=%llu bytes]\n",
899                                 (unsigned long long)addr, size);
900                 goto out;
901         }
902
903         if ((offset + size) > entry->size) {
904                 err_printk(dev, entry, "DMA-API: device driver syncs"
905                                 " DMA memory outside allocated range "
906                                 "[device address=0x%016llx] "
907                                 "[allocation size=%llu bytes] [sync offset=%llu] "
908                                 "[sync size=%llu]\n", entry->dev_addr, entry->size,
909                                 offset, size);
910         }
911
912         if (direction != entry->direction) {
913                 err_printk(dev, entry, "DMA-API: device driver syncs "
914                                 "DMA memory with different direction "
915                                 "[device address=0x%016llx] [size=%llu bytes] "
916                                 "[mapped with %s] [synced with %s]\n",
917                                 (unsigned long long)addr, entry->size,
918                                 dir2name[entry->direction],
919                                 dir2name[direction]);
920         }
921
922         if (entry->direction == DMA_BIDIRECTIONAL)
923                 goto out;
924
925         if (to_cpu && !(entry->direction == DMA_FROM_DEVICE) &&
926                       !(direction == DMA_TO_DEVICE))
927                 err_printk(dev, entry, "DMA-API: device driver syncs "
928                                 "device read-only DMA memory for cpu "
929                                 "[device address=0x%016llx] [size=%llu bytes] "
930                                 "[mapped with %s] [synced with %s]\n",
931                                 (unsigned long long)addr, entry->size,
932                                 dir2name[entry->direction],
933                                 dir2name[direction]);
934
935         if (!to_cpu && !(entry->direction == DMA_TO_DEVICE) &&
936                        !(direction == DMA_FROM_DEVICE))
937                 err_printk(dev, entry, "DMA-API: device driver syncs "
938                                 "device write-only DMA memory to device "
939                                 "[device address=0x%016llx] [size=%llu bytes] "
940                                 "[mapped with %s] [synced with %s]\n",
941                                 (unsigned long long)addr, entry->size,
942                                 dir2name[entry->direction],
943                                 dir2name[direction]);
944
945 out:
946         put_hash_bucket(bucket, &flags);
947
948 }
949
950 void debug_dma_map_page(struct device *dev, struct page *page, size_t offset,
951                         size_t size, int direction, dma_addr_t dma_addr,
952                         bool map_single)
953 {
954         struct dma_debug_entry *entry;
955
956         if (unlikely(global_disable))
957                 return;
958
959         if (unlikely(dma_mapping_error(dev, dma_addr)))
960                 return;
961
962         entry = dma_entry_alloc();
963         if (!entry)
964                 return;
965
966         entry->dev       = dev;
967         entry->type      = dma_debug_page;
968         entry->paddr     = page_to_phys(page) + offset;
969         entry->dev_addr  = dma_addr;
970         entry->size      = size;
971         entry->direction = direction;
972
973         if (map_single)
974                 entry->type = dma_debug_single;
975
976         if (!PageHighMem(page)) {
977                 void *addr = ((char *)page_address(page)) + offset;
978                 check_for_stack(dev, addr);
979                 check_for_illegal_area(dev, addr, size);
980         }
981
982         add_dma_entry(entry);
983 }
984 EXPORT_SYMBOL(debug_dma_map_page);
985
986 void debug_dma_unmap_page(struct device *dev, dma_addr_t addr,
987                           size_t size, int direction, bool map_single)
988 {
989         struct dma_debug_entry ref = {
990                 .type           = dma_debug_page,
991                 .dev            = dev,
992                 .dev_addr       = addr,
993                 .size           = size,
994                 .direction      = direction,
995         };
996
997         if (unlikely(global_disable))
998                 return;
999
1000         if (map_single)
1001                 ref.type = dma_debug_single;
1002
1003         check_unmap(&ref);
1004 }
1005 EXPORT_SYMBOL(debug_dma_unmap_page);
1006
1007 void debug_dma_map_sg(struct device *dev, struct scatterlist *sg,
1008                       int nents, int mapped_ents, int direction)
1009 {
1010         struct dma_debug_entry *entry;
1011         struct scatterlist *s;
1012         int i;
1013
1014         if (unlikely(global_disable))
1015                 return;
1016
1017         for_each_sg(sg, s, mapped_ents, i) {
1018                 entry = dma_entry_alloc();
1019                 if (!entry)
1020                         return;
1021
1022                 entry->type           = dma_debug_sg;
1023                 entry->dev            = dev;
1024                 entry->paddr          = sg_phys(s);
1025                 entry->size           = sg_dma_len(s);
1026                 entry->dev_addr       = sg_dma_address(s);
1027                 entry->direction      = direction;
1028                 entry->sg_call_ents   = nents;
1029                 entry->sg_mapped_ents = mapped_ents;
1030
1031                 if (!PageHighMem(sg_page(s))) {
1032                         check_for_stack(dev, sg_virt(s));
1033                         check_for_illegal_area(dev, sg_virt(s), sg_dma_len(s));
1034                 }
1035
1036                 add_dma_entry(entry);
1037         }
1038 }
1039 EXPORT_SYMBOL(debug_dma_map_sg);
1040
1041 static int get_nr_mapped_entries(struct device *dev, struct scatterlist *s)
1042 {
1043         struct dma_debug_entry *entry;
1044         struct hash_bucket *bucket;
1045         unsigned long flags;
1046         int mapped_ents = 0;
1047         struct dma_debug_entry ref;
1048
1049         ref.dev = dev;
1050         ref.dev_addr = sg_dma_address(s);
1051         ref.size = sg_dma_len(s),
1052
1053         bucket = get_hash_bucket(&ref, &flags);
1054         entry = hash_bucket_find(bucket, &ref);
1055         if (entry)
1056                 mapped_ents = entry->sg_mapped_ents;
1057         put_hash_bucket(bucket, &flags);
1058
1059         return mapped_ents;
1060 }
1061
1062 void debug_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
1063                         int nelems, int dir)
1064 {
1065         struct scatterlist *s;
1066         int mapped_ents = 0, i;
1067
1068         if (unlikely(global_disable))
1069                 return;
1070
1071         for_each_sg(sglist, s, nelems, i) {
1072
1073                 struct dma_debug_entry ref = {
1074                         .type           = dma_debug_sg,
1075                         .dev            = dev,
1076                         .paddr          = sg_phys(s),
1077                         .dev_addr       = sg_dma_address(s),
1078                         .size           = sg_dma_len(s),
1079                         .direction      = dir,
1080                         .sg_call_ents   = 0,
1081                 };
1082
1083                 if (mapped_ents && i >= mapped_ents)
1084                         break;
1085
1086                 if (!i) {
1087                         ref.sg_call_ents = nelems;
1088                         mapped_ents = get_nr_mapped_entries(dev, s);
1089                 }
1090
1091                 check_unmap(&ref);
1092         }
1093 }
1094 EXPORT_SYMBOL(debug_dma_unmap_sg);
1095
1096 void debug_dma_alloc_coherent(struct device *dev, size_t size,
1097                               dma_addr_t dma_addr, void *virt)
1098 {
1099         struct dma_debug_entry *entry;
1100
1101         if (unlikely(global_disable))
1102                 return;
1103
1104         if (unlikely(virt == NULL))
1105                 return;
1106
1107         entry = dma_entry_alloc();
1108         if (!entry)
1109                 return;
1110
1111         entry->type      = dma_debug_coherent;
1112         entry->dev       = dev;
1113         entry->paddr     = virt_to_phys(virt);
1114         entry->size      = size;
1115         entry->dev_addr  = dma_addr;
1116         entry->direction = DMA_BIDIRECTIONAL;
1117
1118         add_dma_entry(entry);
1119 }
1120 EXPORT_SYMBOL(debug_dma_alloc_coherent);
1121
1122 void debug_dma_free_coherent(struct device *dev, size_t size,
1123                          void *virt, dma_addr_t addr)
1124 {
1125         struct dma_debug_entry ref = {
1126                 .type           = dma_debug_coherent,
1127                 .dev            = dev,
1128                 .paddr          = virt_to_phys(virt),
1129                 .dev_addr       = addr,
1130                 .size           = size,
1131                 .direction      = DMA_BIDIRECTIONAL,
1132         };
1133
1134         if (unlikely(global_disable))
1135                 return;
1136
1137         check_unmap(&ref);
1138 }
1139 EXPORT_SYMBOL(debug_dma_free_coherent);
1140
1141 void debug_dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_handle,
1142                                    size_t size, int direction)
1143 {
1144         if (unlikely(global_disable))
1145                 return;
1146
1147         check_sync(dev, dma_handle, size, 0, direction, true);
1148 }
1149 EXPORT_SYMBOL(debug_dma_sync_single_for_cpu);
1150
1151 void debug_dma_sync_single_for_device(struct device *dev,
1152                                       dma_addr_t dma_handle, size_t size,
1153                                       int direction)
1154 {
1155         if (unlikely(global_disable))
1156                 return;
1157
1158         check_sync(dev, dma_handle, size, 0, direction, false);
1159 }
1160 EXPORT_SYMBOL(debug_dma_sync_single_for_device);
1161
1162 void debug_dma_sync_single_range_for_cpu(struct device *dev,
1163                                          dma_addr_t dma_handle,
1164                                          unsigned long offset, size_t size,
1165                                          int direction)
1166 {
1167         if (unlikely(global_disable))
1168                 return;
1169
1170         check_sync(dev, dma_handle, size, offset, direction, true);
1171 }
1172 EXPORT_SYMBOL(debug_dma_sync_single_range_for_cpu);
1173
1174 void debug_dma_sync_single_range_for_device(struct device *dev,
1175                                             dma_addr_t dma_handle,
1176                                             unsigned long offset,
1177                                             size_t size, int direction)
1178 {
1179         if (unlikely(global_disable))
1180                 return;
1181
1182         check_sync(dev, dma_handle, size, offset, direction, false);
1183 }
1184 EXPORT_SYMBOL(debug_dma_sync_single_range_for_device);
1185
1186 void debug_dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
1187                                int nelems, int direction)
1188 {
1189         struct scatterlist *s;
1190         int mapped_ents = 0, i;
1191
1192         if (unlikely(global_disable))
1193                 return;
1194
1195         for_each_sg(sg, s, nelems, i) {
1196                 if (!i)
1197                         mapped_ents = get_nr_mapped_entries(dev, s);
1198
1199                 if (i >= mapped_ents)
1200                         break;
1201
1202                 check_sync(dev, sg_dma_address(s), sg_dma_len(s), 0,
1203                            direction, true);
1204         }
1205 }
1206 EXPORT_SYMBOL(debug_dma_sync_sg_for_cpu);
1207
1208 void debug_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
1209                                   int nelems, int direction)
1210 {
1211         struct scatterlist *s;
1212         int mapped_ents = 0, i;
1213
1214         if (unlikely(global_disable))
1215                 return;
1216
1217         for_each_sg(sg, s, nelems, i) {
1218                 if (!i)
1219                         mapped_ents = get_nr_mapped_entries(dev, s);
1220
1221                 if (i >= mapped_ents)
1222                         break;
1223
1224                 check_sync(dev, sg_dma_address(s), sg_dma_len(s), 0,
1225                            direction, false);
1226         }
1227 }
1228 EXPORT_SYMBOL(debug_dma_sync_sg_for_device);
1229
1230 static int __init dma_debug_driver_setup(char *str)
1231 {
1232         int i;
1233
1234         for (i = 0; i < NAME_MAX_LEN - 1; ++i, ++str) {
1235                 current_driver_name[i] = *str;
1236                 if (*str == 0)
1237                         break;
1238         }
1239
1240         if (current_driver_name[0])
1241                 printk(KERN_INFO "DMA-API: enable driver filter for "
1242                                  "driver [%s]\n", current_driver_name);
1243
1244
1245         return 1;
1246 }
1247 __setup("dma_debug_driver=", dma_debug_driver_setup);