random32: fix off-by-one in seeding requirement
[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/export.h>
28 #include <linux/device.h>
29 #include <linux/types.h>
30 #include <linux/sched.h>
31 #include <linux/ctype.h>
32 #include <linux/list.h>
33 #include <linux/slab.h>
34
35 #include <asm/sections.h>
36
37 #define HASH_SIZE       1024ULL
38 #define HASH_FN_SHIFT   13
39 #define HASH_FN_MASK    (HASH_SIZE - 1)
40
41 enum {
42         dma_debug_single,
43         dma_debug_page,
44         dma_debug_sg,
45         dma_debug_coherent,
46 };
47
48 enum map_err_types {
49         MAP_ERR_CHECK_NOT_APPLICABLE,
50         MAP_ERR_NOT_CHECKED,
51         MAP_ERR_CHECKED,
52 };
53
54 #define DMA_DEBUG_STACKTRACE_ENTRIES 5
55
56 struct dma_debug_entry {
57         struct list_head list;
58         struct device    *dev;
59         int              type;
60         phys_addr_t      paddr;
61         u64              dev_addr;
62         u64              size;
63         int              direction;
64         int              sg_call_ents;
65         int              sg_mapped_ents;
66         enum map_err_types  map_err_type;
67 #ifdef CONFIG_STACKTRACE
68         struct           stack_trace stacktrace;
69         unsigned long    st_entries[DMA_DEBUG_STACKTRACE_ENTRIES];
70 #endif
71 };
72
73 typedef bool (*match_fn)(struct dma_debug_entry *, struct dma_debug_entry *);
74
75 struct hash_bucket {
76         struct list_head list;
77         spinlock_t lock;
78 } ____cacheline_aligned_in_smp;
79
80 /* Hash list to save the allocated dma addresses */
81 static struct hash_bucket dma_entry_hash[HASH_SIZE];
82 /* List of pre-allocated dma_debug_entry's */
83 static LIST_HEAD(free_entries);
84 /* Lock for the list above */
85 static DEFINE_SPINLOCK(free_entries_lock);
86
87 /* Global disable flag - will be set in case of an error */
88 static u32 global_disable __read_mostly;
89
90 /* Global error count */
91 static u32 error_count;
92
93 /* Global error show enable*/
94 static u32 show_all_errors __read_mostly;
95 /* Number of errors to show */
96 static u32 show_num_errors = 1;
97
98 static u32 num_free_entries;
99 static u32 min_free_entries;
100 static u32 nr_total_entries;
101
102 /* number of preallocated entries requested by kernel cmdline */
103 static u32 req_entries;
104
105 /* debugfs dentry's for the stuff above */
106 static struct dentry *dma_debug_dent        __read_mostly;
107 static struct dentry *global_disable_dent   __read_mostly;
108 static struct dentry *error_count_dent      __read_mostly;
109 static struct dentry *show_all_errors_dent  __read_mostly;
110 static struct dentry *show_num_errors_dent  __read_mostly;
111 static struct dentry *num_free_entries_dent __read_mostly;
112 static struct dentry *min_free_entries_dent __read_mostly;
113 static struct dentry *filter_dent           __read_mostly;
114
115 /* per-driver filter related state */
116
117 #define NAME_MAX_LEN    64
118
119 static char                  current_driver_name[NAME_MAX_LEN] __read_mostly;
120 static struct device_driver *current_driver                    __read_mostly;
121
122 static DEFINE_RWLOCK(driver_name_lock);
123
124 static const char *const maperr2str[] = {
125         [MAP_ERR_CHECK_NOT_APPLICABLE] = "dma map error check not applicable",
126         [MAP_ERR_NOT_CHECKED] = "dma map error not checked",
127         [MAP_ERR_CHECKED] = "dma map error checked",
128 };
129
130 static const char *type2name[4] = { "single", "page",
131                                     "scather-gather", "coherent" };
132
133 static const char *dir2name[4] = { "DMA_BIDIRECTIONAL", "DMA_TO_DEVICE",
134                                    "DMA_FROM_DEVICE", "DMA_NONE" };
135
136 /*
137  * The access to some variables in this macro is racy. We can't use atomic_t
138  * here because all these variables are exported to debugfs. Some of them even
139  * writeable. This is also the reason why a lock won't help much. But anyway,
140  * the races are no big deal. Here is why:
141  *
142  *   error_count: the addition is racy, but the worst thing that can happen is
143  *                that we don't count some errors
144  *   show_num_errors: the subtraction is racy. Also no big deal because in
145  *                    worst case this will result in one warning more in the
146  *                    system log than the user configured. This variable is
147  *                    writeable via debugfs.
148  */
149 static inline void dump_entry_trace(struct dma_debug_entry *entry)
150 {
151 #ifdef CONFIG_STACKTRACE
152         if (entry) {
153                 pr_warning("Mapped at:\n");
154                 print_stack_trace(&entry->stacktrace, 0);
155         }
156 #endif
157 }
158
159 static bool driver_filter(struct device *dev)
160 {
161         struct device_driver *drv;
162         unsigned long flags;
163         bool ret;
164
165         /* driver filter off */
166         if (likely(!current_driver_name[0]))
167                 return true;
168
169         /* driver filter on and initialized */
170         if (current_driver && dev && dev->driver == current_driver)
171                 return true;
172
173         /* driver filter on, but we can't filter on a NULL device... */
174         if (!dev)
175                 return false;
176
177         if (current_driver || !current_driver_name[0])
178                 return false;
179
180         /* driver filter on but not yet initialized */
181         drv = dev->driver;
182         if (!drv)
183                 return false;
184
185         /* lock to protect against change of current_driver_name */
186         read_lock_irqsave(&driver_name_lock, flags);
187
188         ret = false;
189         if (drv->name &&
190             strncmp(current_driver_name, drv->name, NAME_MAX_LEN - 1) == 0) {
191                 current_driver = drv;
192                 ret = true;
193         }
194
195         read_unlock_irqrestore(&driver_name_lock, flags);
196
197         return ret;
198 }
199
200 #define err_printk(dev, entry, format, arg...) do {                     \
201                 error_count += 1;                                       \
202                 if (driver_filter(dev) &&                               \
203                     (show_all_errors || show_num_errors > 0)) {         \
204                         WARN(1, "%s %s: " format,                       \
205                              dev ? dev_driver_string(dev) : "NULL",     \
206                              dev ? dev_name(dev) : "NULL", ## arg);     \
207                         dump_entry_trace(entry);                        \
208                 }                                                       \
209                 if (!show_all_errors && show_num_errors > 0)            \
210                         show_num_errors -= 1;                           \
211         } while (0);
212
213 /*
214  * Hash related functions
215  *
216  * Every DMA-API request is saved into a struct dma_debug_entry. To
217  * have quick access to these structs they are stored into a hash.
218  */
219 static int hash_fn(struct dma_debug_entry *entry)
220 {
221         /*
222          * Hash function is based on the dma address.
223          * We use bits 20-27 here as the index into the hash
224          */
225         return (entry->dev_addr >> HASH_FN_SHIFT) & HASH_FN_MASK;
226 }
227
228 /*
229  * Request exclusive access to a hash bucket for a given dma_debug_entry.
230  */
231 static struct hash_bucket *get_hash_bucket(struct dma_debug_entry *entry,
232                                            unsigned long *flags)
233 {
234         int idx = hash_fn(entry);
235         unsigned long __flags;
236
237         spin_lock_irqsave(&dma_entry_hash[idx].lock, __flags);
238         *flags = __flags;
239         return &dma_entry_hash[idx];
240 }
241
242 /*
243  * Give up exclusive access to the hash bucket
244  */
245 static void put_hash_bucket(struct hash_bucket *bucket,
246                             unsigned long *flags)
247 {
248         unsigned long __flags = *flags;
249
250         spin_unlock_irqrestore(&bucket->lock, __flags);
251 }
252
253 static bool exact_match(struct dma_debug_entry *a, struct dma_debug_entry *b)
254 {
255         return ((a->dev_addr == b->dev_addr) &&
256                 (a->dev == b->dev)) ? true : false;
257 }
258
259 static bool containing_match(struct dma_debug_entry *a,
260                              struct dma_debug_entry *b)
261 {
262         if (a->dev != b->dev)
263                 return false;
264
265         if ((b->dev_addr <= a->dev_addr) &&
266             ((b->dev_addr + b->size) >= (a->dev_addr + a->size)))
267                 return true;
268
269         return false;
270 }
271
272 /*
273  * Search a given entry in the hash bucket list
274  */
275 static struct dma_debug_entry *__hash_bucket_find(struct hash_bucket *bucket,
276                                                   struct dma_debug_entry *ref,
277                                                   match_fn match)
278 {
279         struct dma_debug_entry *entry, *ret = NULL;
280         int matches = 0, match_lvl, last_lvl = -1;
281
282         list_for_each_entry(entry, &bucket->list, list) {
283                 if (!match(ref, entry))
284                         continue;
285
286                 /*
287                  * Some drivers map the same physical address multiple
288                  * times. Without a hardware IOMMU this results in the
289                  * same device addresses being put into the dma-debug
290                  * hash multiple times too. This can result in false
291                  * positives being reported. Therefore we implement a
292                  * best-fit algorithm here which returns the entry from
293                  * the hash which fits best to the reference value
294                  * instead of the first-fit.
295                  */
296                 matches += 1;
297                 match_lvl = 0;
298                 entry->size         == ref->size         ? ++match_lvl : 0;
299                 entry->type         == ref->type         ? ++match_lvl : 0;
300                 entry->direction    == ref->direction    ? ++match_lvl : 0;
301                 entry->sg_call_ents == ref->sg_call_ents ? ++match_lvl : 0;
302
303                 if (match_lvl == 4) {
304                         /* perfect-fit - return the result */
305                         return entry;
306                 } else if (match_lvl > last_lvl) {
307                         /*
308                          * We found an entry that fits better then the
309                          * previous one or it is the 1st match.
310                          */
311                         last_lvl = match_lvl;
312                         ret      = entry;
313                 }
314         }
315
316         /*
317          * If we have multiple matches but no perfect-fit, just return
318          * NULL.
319          */
320         ret = (matches == 1) ? ret : NULL;
321
322         return ret;
323 }
324
325 static struct dma_debug_entry *bucket_find_exact(struct hash_bucket *bucket,
326                                                  struct dma_debug_entry *ref)
327 {
328         return __hash_bucket_find(bucket, ref, exact_match);
329 }
330
331 static struct dma_debug_entry *bucket_find_contain(struct hash_bucket **bucket,
332                                                    struct dma_debug_entry *ref,
333                                                    unsigned long *flags)
334 {
335
336         unsigned int max_range = dma_get_max_seg_size(ref->dev);
337         struct dma_debug_entry *entry, index = *ref;
338         unsigned int range = 0;
339
340         while (range <= max_range) {
341                 entry = __hash_bucket_find(*bucket, &index, containing_match);
342
343                 if (entry)
344                         return entry;
345
346                 /*
347                  * Nothing found, go back a hash bucket
348                  */
349                 put_hash_bucket(*bucket, flags);
350                 range          += (1 << HASH_FN_SHIFT);
351                 index.dev_addr -= (1 << HASH_FN_SHIFT);
352                 *bucket = get_hash_bucket(&index, flags);
353         }
354
355         return NULL;
356 }
357
358 /*
359  * Add an entry to a hash bucket
360  */
361 static void hash_bucket_add(struct hash_bucket *bucket,
362                             struct dma_debug_entry *entry)
363 {
364         list_add_tail(&entry->list, &bucket->list);
365 }
366
367 /*
368  * Remove entry from a hash bucket list
369  */
370 static void hash_bucket_del(struct dma_debug_entry *entry)
371 {
372         list_del(&entry->list);
373 }
374
375 /*
376  * Dump mapping entries for debugging purposes
377  */
378 void debug_dma_dump_mappings(struct device *dev)
379 {
380         int idx;
381
382         for (idx = 0; idx < HASH_SIZE; idx++) {
383                 struct hash_bucket *bucket = &dma_entry_hash[idx];
384                 struct dma_debug_entry *entry;
385                 unsigned long flags;
386
387                 spin_lock_irqsave(&bucket->lock, flags);
388
389                 list_for_each_entry(entry, &bucket->list, list) {
390                         if (!dev || dev == entry->dev) {
391                                 dev_info(entry->dev,
392                                          "%s idx %d P=%Lx D=%Lx L=%Lx %s %s\n",
393                                          type2name[entry->type], idx,
394                                          (unsigned long long)entry->paddr,
395                                          entry->dev_addr, entry->size,
396                                          dir2name[entry->direction],
397                                          maperr2str[entry->map_err_type]);
398                         }
399                 }
400
401                 spin_unlock_irqrestore(&bucket->lock, flags);
402         }
403 }
404 EXPORT_SYMBOL(debug_dma_dump_mappings);
405
406 /*
407  * Wrapper function for adding an entry to the hash.
408  * This function takes care of locking itself.
409  */
410 static void add_dma_entry(struct dma_debug_entry *entry)
411 {
412         struct hash_bucket *bucket;
413         unsigned long flags;
414
415         bucket = get_hash_bucket(entry, &flags);
416         hash_bucket_add(bucket, entry);
417         put_hash_bucket(bucket, &flags);
418 }
419
420 static struct dma_debug_entry *__dma_entry_alloc(void)
421 {
422         struct dma_debug_entry *entry;
423
424         entry = list_entry(free_entries.next, struct dma_debug_entry, list);
425         list_del(&entry->list);
426         memset(entry, 0, sizeof(*entry));
427
428         num_free_entries -= 1;
429         if (num_free_entries < min_free_entries)
430                 min_free_entries = num_free_entries;
431
432         return entry;
433 }
434
435 /* struct dma_entry allocator
436  *
437  * The next two functions implement the allocator for
438  * struct dma_debug_entries.
439  */
440 static struct dma_debug_entry *dma_entry_alloc(void)
441 {
442         struct dma_debug_entry *entry;
443         unsigned long flags;
444
445         spin_lock_irqsave(&free_entries_lock, flags);
446
447         if (list_empty(&free_entries)) {
448                 pr_err("DMA-API: debugging out of memory - disabling\n");
449                 global_disable = true;
450                 spin_unlock_irqrestore(&free_entries_lock, flags);
451                 return NULL;
452         }
453
454         entry = __dma_entry_alloc();
455
456         spin_unlock_irqrestore(&free_entries_lock, flags);
457
458 #ifdef CONFIG_STACKTRACE
459         entry->stacktrace.max_entries = DMA_DEBUG_STACKTRACE_ENTRIES;
460         entry->stacktrace.entries = entry->st_entries;
461         entry->stacktrace.skip = 2;
462         save_stack_trace(&entry->stacktrace);
463 #endif
464
465         return entry;
466 }
467
468 static void dma_entry_free(struct dma_debug_entry *entry)
469 {
470         unsigned long flags;
471
472         /*
473          * add to beginning of the list - this way the entries are
474          * more likely cache hot when they are reallocated.
475          */
476         spin_lock_irqsave(&free_entries_lock, flags);
477         list_add(&entry->list, &free_entries);
478         num_free_entries += 1;
479         spin_unlock_irqrestore(&free_entries_lock, flags);
480 }
481
482 int dma_debug_resize_entries(u32 num_entries)
483 {
484         int i, delta, ret = 0;
485         unsigned long flags;
486         struct dma_debug_entry *entry;
487         LIST_HEAD(tmp);
488
489         spin_lock_irqsave(&free_entries_lock, flags);
490
491         if (nr_total_entries < num_entries) {
492                 delta = num_entries - nr_total_entries;
493
494                 spin_unlock_irqrestore(&free_entries_lock, flags);
495
496                 for (i = 0; i < delta; i++) {
497                         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
498                         if (!entry)
499                                 break;
500
501                         list_add_tail(&entry->list, &tmp);
502                 }
503
504                 spin_lock_irqsave(&free_entries_lock, flags);
505
506                 list_splice(&tmp, &free_entries);
507                 nr_total_entries += i;
508                 num_free_entries += i;
509         } else {
510                 delta = nr_total_entries - num_entries;
511
512                 for (i = 0; i < delta && !list_empty(&free_entries); i++) {
513                         entry = __dma_entry_alloc();
514                         kfree(entry);
515                 }
516
517                 nr_total_entries -= i;
518         }
519
520         if (nr_total_entries != num_entries)
521                 ret = 1;
522
523         spin_unlock_irqrestore(&free_entries_lock, flags);
524
525         return ret;
526 }
527 EXPORT_SYMBOL(dma_debug_resize_entries);
528
529 /*
530  * DMA-API debugging init code
531  *
532  * The init code does two things:
533  *   1. Initialize core data structures
534  *   2. Preallocate a given number of dma_debug_entry structs
535  */
536
537 static int prealloc_memory(u32 num_entries)
538 {
539         struct dma_debug_entry *entry, *next_entry;
540         int i;
541
542         for (i = 0; i < num_entries; ++i) {
543                 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
544                 if (!entry)
545                         goto out_err;
546
547                 list_add_tail(&entry->list, &free_entries);
548         }
549
550         num_free_entries = num_entries;
551         min_free_entries = num_entries;
552
553         pr_info("DMA-API: preallocated %d debug entries\n", num_entries);
554
555         return 0;
556
557 out_err:
558
559         list_for_each_entry_safe(entry, next_entry, &free_entries, list) {
560                 list_del(&entry->list);
561                 kfree(entry);
562         }
563
564         return -ENOMEM;
565 }
566
567 static ssize_t filter_read(struct file *file, char __user *user_buf,
568                            size_t count, loff_t *ppos)
569 {
570         char buf[NAME_MAX_LEN + 1];
571         unsigned long flags;
572         int len;
573
574         if (!current_driver_name[0])
575                 return 0;
576
577         /*
578          * We can't copy to userspace directly because current_driver_name can
579          * only be read under the driver_name_lock with irqs disabled. So
580          * create a temporary copy first.
581          */
582         read_lock_irqsave(&driver_name_lock, flags);
583         len = scnprintf(buf, NAME_MAX_LEN + 1, "%s\n", current_driver_name);
584         read_unlock_irqrestore(&driver_name_lock, flags);
585
586         return simple_read_from_buffer(user_buf, count, ppos, buf, len);
587 }
588
589 static ssize_t filter_write(struct file *file, const char __user *userbuf,
590                             size_t count, loff_t *ppos)
591 {
592         char buf[NAME_MAX_LEN];
593         unsigned long flags;
594         size_t len;
595         int i;
596
597         /*
598          * We can't copy from userspace directly. Access to
599          * current_driver_name is protected with a write_lock with irqs
600          * disabled. Since copy_from_user can fault and may sleep we
601          * need to copy to temporary buffer first
602          */
603         len = min(count, (size_t)(NAME_MAX_LEN - 1));
604         if (copy_from_user(buf, userbuf, len))
605                 return -EFAULT;
606
607         buf[len] = 0;
608
609         write_lock_irqsave(&driver_name_lock, flags);
610
611         /*
612          * Now handle the string we got from userspace very carefully.
613          * The rules are:
614          *         - only use the first token we got
615          *         - token delimiter is everything looking like a space
616          *           character (' ', '\n', '\t' ...)
617          *
618          */
619         if (!isalnum(buf[0])) {
620                 /*
621                  * If the first character userspace gave us is not
622                  * alphanumerical then assume the filter should be
623                  * switched off.
624                  */
625                 if (current_driver_name[0])
626                         pr_info("DMA-API: switching off dma-debug driver filter\n");
627                 current_driver_name[0] = 0;
628                 current_driver = NULL;
629                 goto out_unlock;
630         }
631
632         /*
633          * Now parse out the first token and use it as the name for the
634          * driver to filter for.
635          */
636         for (i = 0; i < NAME_MAX_LEN - 1; ++i) {
637                 current_driver_name[i] = buf[i];
638                 if (isspace(buf[i]) || buf[i] == ' ' || buf[i] == 0)
639                         break;
640         }
641         current_driver_name[i] = 0;
642         current_driver = NULL;
643
644         pr_info("DMA-API: enable driver filter for driver [%s]\n",
645                 current_driver_name);
646
647 out_unlock:
648         write_unlock_irqrestore(&driver_name_lock, flags);
649
650         return count;
651 }
652
653 static const struct file_operations filter_fops = {
654         .read  = filter_read,
655         .write = filter_write,
656         .llseek = default_llseek,
657 };
658
659 static int dma_debug_fs_init(void)
660 {
661         dma_debug_dent = debugfs_create_dir("dma-api", NULL);
662         if (!dma_debug_dent) {
663                 pr_err("DMA-API: can not create debugfs directory\n");
664                 return -ENOMEM;
665         }
666
667         global_disable_dent = debugfs_create_bool("disabled", 0444,
668                         dma_debug_dent,
669                         &global_disable);
670         if (!global_disable_dent)
671                 goto out_err;
672
673         error_count_dent = debugfs_create_u32("error_count", 0444,
674                         dma_debug_dent, &error_count);
675         if (!error_count_dent)
676                 goto out_err;
677
678         show_all_errors_dent = debugfs_create_u32("all_errors", 0644,
679                         dma_debug_dent,
680                         &show_all_errors);
681         if (!show_all_errors_dent)
682                 goto out_err;
683
684         show_num_errors_dent = debugfs_create_u32("num_errors", 0644,
685                         dma_debug_dent,
686                         &show_num_errors);
687         if (!show_num_errors_dent)
688                 goto out_err;
689
690         num_free_entries_dent = debugfs_create_u32("num_free_entries", 0444,
691                         dma_debug_dent,
692                         &num_free_entries);
693         if (!num_free_entries_dent)
694                 goto out_err;
695
696         min_free_entries_dent = debugfs_create_u32("min_free_entries", 0444,
697                         dma_debug_dent,
698                         &min_free_entries);
699         if (!min_free_entries_dent)
700                 goto out_err;
701
702         filter_dent = debugfs_create_file("driver_filter", 0644,
703                                           dma_debug_dent, NULL, &filter_fops);
704         if (!filter_dent)
705                 goto out_err;
706
707         return 0;
708
709 out_err:
710         debugfs_remove_recursive(dma_debug_dent);
711
712         return -ENOMEM;
713 }
714
715 static int device_dma_allocations(struct device *dev, struct dma_debug_entry **out_entry)
716 {
717         struct dma_debug_entry *entry;
718         unsigned long flags;
719         int count = 0, i;
720
721         local_irq_save(flags);
722
723         for (i = 0; i < HASH_SIZE; ++i) {
724                 spin_lock(&dma_entry_hash[i].lock);
725                 list_for_each_entry(entry, &dma_entry_hash[i].list, list) {
726                         if (entry->dev == dev) {
727                                 count += 1;
728                                 *out_entry = entry;
729                         }
730                 }
731                 spin_unlock(&dma_entry_hash[i].lock);
732         }
733
734         local_irq_restore(flags);
735
736         return count;
737 }
738
739 static int dma_debug_device_change(struct notifier_block *nb, unsigned long action, void *data)
740 {
741         struct device *dev = data;
742         struct dma_debug_entry *uninitialized_var(entry);
743         int count;
744
745         if (global_disable)
746                 return 0;
747
748         switch (action) {
749         case BUS_NOTIFY_UNBOUND_DRIVER:
750                 count = device_dma_allocations(dev, &entry);
751                 if (count == 0)
752                         break;
753                 err_printk(dev, entry, "DMA-API: device driver has pending "
754                                 "DMA allocations while released from device "
755                                 "[count=%d]\n"
756                                 "One of leaked entries details: "
757                                 "[device address=0x%016llx] [size=%llu bytes] "
758                                 "[mapped with %s] [mapped as %s]\n",
759                         count, entry->dev_addr, entry->size,
760                         dir2name[entry->direction], type2name[entry->type]);
761                 break;
762         default:
763                 break;
764         }
765
766         return 0;
767 }
768
769 void dma_debug_add_bus(struct bus_type *bus)
770 {
771         struct notifier_block *nb;
772
773         if (global_disable)
774                 return;
775
776         nb = kzalloc(sizeof(struct notifier_block), GFP_KERNEL);
777         if (nb == NULL) {
778                 pr_err("dma_debug_add_bus: out of memory\n");
779                 return;
780         }
781
782         nb->notifier_call = dma_debug_device_change;
783
784         bus_register_notifier(bus, nb);
785 }
786
787 /*
788  * Let the architectures decide how many entries should be preallocated.
789  */
790 void dma_debug_init(u32 num_entries)
791 {
792         int i;
793
794         if (global_disable)
795                 return;
796
797         for (i = 0; i < HASH_SIZE; ++i) {
798                 INIT_LIST_HEAD(&dma_entry_hash[i].list);
799                 spin_lock_init(&dma_entry_hash[i].lock);
800         }
801
802         if (dma_debug_fs_init() != 0) {
803                 pr_err("DMA-API: error creating debugfs entries - disabling\n");
804                 global_disable = true;
805
806                 return;
807         }
808
809         if (req_entries)
810                 num_entries = req_entries;
811
812         if (prealloc_memory(num_entries) != 0) {
813                 pr_err("DMA-API: debugging out of memory error - disabled\n");
814                 global_disable = true;
815
816                 return;
817         }
818
819         nr_total_entries = num_free_entries;
820
821         pr_info("DMA-API: debugging enabled by kernel config\n");
822 }
823
824 static __init int dma_debug_cmdline(char *str)
825 {
826         if (!str)
827                 return -EINVAL;
828
829         if (strncmp(str, "off", 3) == 0) {
830                 pr_info("DMA-API: debugging disabled on kernel command line\n");
831                 global_disable = true;
832         }
833
834         return 0;
835 }
836
837 static __init int dma_debug_entries_cmdline(char *str)
838 {
839         int res;
840
841         if (!str)
842                 return -EINVAL;
843
844         res = get_option(&str, &req_entries);
845
846         if (!res)
847                 req_entries = 0;
848
849         return 0;
850 }
851
852 __setup("dma_debug=", dma_debug_cmdline);
853 __setup("dma_debug_entries=", dma_debug_entries_cmdline);
854
855 static void check_unmap(struct dma_debug_entry *ref)
856 {
857         struct dma_debug_entry *entry;
858         struct hash_bucket *bucket;
859         unsigned long flags;
860
861         bucket = get_hash_bucket(ref, &flags);
862         entry = bucket_find_exact(bucket, ref);
863
864         if (!entry) {
865                 /* must drop lock before calling dma_mapping_error */
866                 put_hash_bucket(bucket, &flags);
867
868                 if (dma_mapping_error(ref->dev, ref->dev_addr)) {
869                         err_printk(ref->dev, NULL,
870                                    "DMA-API: device driver tries to free an "
871                                    "invalid DMA memory address\n");
872                 } else {
873                         err_printk(ref->dev, NULL,
874                                    "DMA-API: device driver tries to free DMA "
875                                    "memory it has not allocated [device "
876                                    "address=0x%016llx] [size=%llu bytes]\n",
877                                    ref->dev_addr, ref->size);
878                 }
879                 return;
880         }
881
882         if (ref->size != entry->size) {
883                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
884                            "DMA memory with different size "
885                            "[device address=0x%016llx] [map size=%llu bytes] "
886                            "[unmap size=%llu bytes]\n",
887                            ref->dev_addr, entry->size, ref->size);
888         }
889
890         if (ref->type != entry->type) {
891                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
892                            "DMA memory with wrong function "
893                            "[device address=0x%016llx] [size=%llu bytes] "
894                            "[mapped as %s] [unmapped as %s]\n",
895                            ref->dev_addr, ref->size,
896                            type2name[entry->type], type2name[ref->type]);
897         } else if ((entry->type == dma_debug_coherent) &&
898                    (ref->paddr != entry->paddr)) {
899                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
900                            "DMA memory with different CPU address "
901                            "[device address=0x%016llx] [size=%llu bytes] "
902                            "[cpu alloc address=0x%016llx] "
903                            "[cpu free address=0x%016llx]",
904                            ref->dev_addr, ref->size,
905                            (unsigned long long)entry->paddr,
906                            (unsigned long long)ref->paddr);
907         }
908
909         if (ref->sg_call_ents && ref->type == dma_debug_sg &&
910             ref->sg_call_ents != entry->sg_call_ents) {
911                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
912                            "DMA sg list with different entry count "
913                            "[map count=%d] [unmap count=%d]\n",
914                            entry->sg_call_ents, ref->sg_call_ents);
915         }
916
917         /*
918          * This may be no bug in reality - but most implementations of the
919          * DMA API don't handle this properly, so check for it here
920          */
921         if (ref->direction != entry->direction) {
922                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
923                            "DMA memory with different direction "
924                            "[device address=0x%016llx] [size=%llu bytes] "
925                            "[mapped with %s] [unmapped with %s]\n",
926                            ref->dev_addr, ref->size,
927                            dir2name[entry->direction],
928                            dir2name[ref->direction]);
929         }
930
931         if (entry->map_err_type == MAP_ERR_NOT_CHECKED) {
932                 err_printk(ref->dev, entry,
933                            "DMA-API: device driver failed to check map error"
934                            "[device address=0x%016llx] [size=%llu bytes] "
935                            "[mapped as %s]",
936                            ref->dev_addr, ref->size,
937                            type2name[entry->type]);
938         }
939
940         hash_bucket_del(entry);
941         dma_entry_free(entry);
942
943         put_hash_bucket(bucket, &flags);
944 }
945
946 static void check_for_stack(struct device *dev, void *addr)
947 {
948         if (object_is_on_stack(addr))
949                 err_printk(dev, NULL, "DMA-API: device driver maps memory from"
950                                 "stack [addr=%p]\n", addr);
951 }
952
953 static inline bool overlap(void *addr, unsigned long len, void *start, void *end)
954 {
955         unsigned long a1 = (unsigned long)addr;
956         unsigned long b1 = a1 + len;
957         unsigned long a2 = (unsigned long)start;
958         unsigned long b2 = (unsigned long)end;
959
960         return !(b1 <= a2 || a1 >= b2);
961 }
962
963 static void check_for_illegal_area(struct device *dev, void *addr, unsigned long len)
964 {
965         if (overlap(addr, len, _text, _etext) ||
966             overlap(addr, len, __start_rodata, __end_rodata))
967                 err_printk(dev, NULL, "DMA-API: device driver maps memory from kernel text or rodata [addr=%p] [len=%lu]\n", addr, len);
968 }
969
970 static void check_sync(struct device *dev,
971                        struct dma_debug_entry *ref,
972                        bool to_cpu)
973 {
974         struct dma_debug_entry *entry;
975         struct hash_bucket *bucket;
976         unsigned long flags;
977
978         bucket = get_hash_bucket(ref, &flags);
979
980         entry = bucket_find_contain(&bucket, ref, &flags);
981
982         if (!entry) {
983                 err_printk(dev, NULL, "DMA-API: device driver tries "
984                                 "to sync DMA memory it has not allocated "
985                                 "[device address=0x%016llx] [size=%llu bytes]\n",
986                                 (unsigned long long)ref->dev_addr, ref->size);
987                 goto out;
988         }
989
990         if (ref->size > entry->size) {
991                 err_printk(dev, entry, "DMA-API: device driver syncs"
992                                 " DMA memory outside allocated range "
993                                 "[device address=0x%016llx] "
994                                 "[allocation size=%llu bytes] "
995                                 "[sync offset+size=%llu]\n",
996                                 entry->dev_addr, entry->size,
997                                 ref->size);
998         }
999
1000         if (entry->direction == DMA_BIDIRECTIONAL)
1001                 goto out;
1002
1003         if (ref->direction != entry->direction) {
1004                 err_printk(dev, entry, "DMA-API: device driver syncs "
1005                                 "DMA memory with different direction "
1006                                 "[device address=0x%016llx] [size=%llu bytes] "
1007                                 "[mapped with %s] [synced with %s]\n",
1008                                 (unsigned long long)ref->dev_addr, entry->size,
1009                                 dir2name[entry->direction],
1010                                 dir2name[ref->direction]);
1011         }
1012
1013         if (to_cpu && !(entry->direction == DMA_FROM_DEVICE) &&
1014                       !(ref->direction == DMA_TO_DEVICE))
1015                 err_printk(dev, entry, "DMA-API: device driver syncs "
1016                                 "device read-only DMA memory for cpu "
1017                                 "[device address=0x%016llx] [size=%llu bytes] "
1018                                 "[mapped with %s] [synced with %s]\n",
1019                                 (unsigned long long)ref->dev_addr, entry->size,
1020                                 dir2name[entry->direction],
1021                                 dir2name[ref->direction]);
1022
1023         if (!to_cpu && !(entry->direction == DMA_TO_DEVICE) &&
1024                        !(ref->direction == DMA_FROM_DEVICE))
1025                 err_printk(dev, entry, "DMA-API: device driver syncs "
1026                                 "device write-only DMA memory to device "
1027                                 "[device address=0x%016llx] [size=%llu bytes] "
1028                                 "[mapped with %s] [synced with %s]\n",
1029                                 (unsigned long long)ref->dev_addr, entry->size,
1030                                 dir2name[entry->direction],
1031                                 dir2name[ref->direction]);
1032
1033 out:
1034         put_hash_bucket(bucket, &flags);
1035 }
1036
1037 void debug_dma_map_page(struct device *dev, struct page *page, size_t offset,
1038                         size_t size, int direction, dma_addr_t dma_addr,
1039                         bool map_single)
1040 {
1041         struct dma_debug_entry *entry;
1042
1043         if (unlikely(global_disable))
1044                 return;
1045
1046         if (dma_mapping_error(dev, dma_addr))
1047                 return;
1048
1049         entry = dma_entry_alloc();
1050         if (!entry)
1051                 return;
1052
1053         entry->dev       = dev;
1054         entry->type      = dma_debug_page;
1055         entry->paddr     = page_to_phys(page) + offset;
1056         entry->dev_addr  = dma_addr;
1057         entry->size      = size;
1058         entry->direction = direction;
1059         entry->map_err_type = MAP_ERR_NOT_CHECKED;
1060
1061         if (map_single)
1062                 entry->type = dma_debug_single;
1063
1064         if (!PageHighMem(page)) {
1065                 void *addr = page_address(page) + offset;
1066
1067                 check_for_stack(dev, addr);
1068                 check_for_illegal_area(dev, addr, size);
1069         }
1070
1071         add_dma_entry(entry);
1072 }
1073 EXPORT_SYMBOL(debug_dma_map_page);
1074
1075 void debug_dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
1076 {
1077         struct dma_debug_entry ref;
1078         struct dma_debug_entry *entry;
1079         struct hash_bucket *bucket;
1080         unsigned long flags;
1081
1082         if (unlikely(global_disable))
1083                 return;
1084
1085         ref.dev = dev;
1086         ref.dev_addr = dma_addr;
1087         bucket = get_hash_bucket(&ref, &flags);
1088
1089         list_for_each_entry(entry, &bucket->list, list) {
1090                 if (!exact_match(&ref, entry))
1091                         continue;
1092
1093                 /*
1094                  * The same physical address can be mapped multiple
1095                  * times. Without a hardware IOMMU this results in the
1096                  * same device addresses being put into the dma-debug
1097                  * hash multiple times too. This can result in false
1098                  * positives being reported. Therefore we implement a
1099                  * best-fit algorithm here which updates the first entry
1100                  * from the hash which fits the reference value and is
1101                  * not currently listed as being checked.
1102                  */
1103                 if (entry->map_err_type == MAP_ERR_NOT_CHECKED) {
1104                         entry->map_err_type = MAP_ERR_CHECKED;
1105                         break;
1106                 }
1107         }
1108
1109         put_hash_bucket(bucket, &flags);
1110 }
1111 EXPORT_SYMBOL(debug_dma_mapping_error);
1112
1113 void debug_dma_unmap_page(struct device *dev, dma_addr_t addr,
1114                           size_t size, int direction, bool map_single)
1115 {
1116         struct dma_debug_entry ref = {
1117                 .type           = dma_debug_page,
1118                 .dev            = dev,
1119                 .dev_addr       = addr,
1120                 .size           = size,
1121                 .direction      = direction,
1122         };
1123
1124         if (unlikely(global_disable))
1125                 return;
1126
1127         if (map_single)
1128                 ref.type = dma_debug_single;
1129
1130         check_unmap(&ref);
1131 }
1132 EXPORT_SYMBOL(debug_dma_unmap_page);
1133
1134 void debug_dma_map_sg(struct device *dev, struct scatterlist *sg,
1135                       int nents, int mapped_ents, int direction)
1136 {
1137         struct dma_debug_entry *entry;
1138         struct scatterlist *s;
1139         int i;
1140
1141         if (unlikely(global_disable))
1142                 return;
1143
1144         for_each_sg(sg, s, mapped_ents, i) {
1145                 entry = dma_entry_alloc();
1146                 if (!entry)
1147                         return;
1148
1149                 entry->type           = dma_debug_sg;
1150                 entry->dev            = dev;
1151                 entry->paddr          = sg_phys(s);
1152                 entry->size           = sg_dma_len(s);
1153                 entry->dev_addr       = sg_dma_address(s);
1154                 entry->direction      = direction;
1155                 entry->sg_call_ents   = nents;
1156                 entry->sg_mapped_ents = mapped_ents;
1157
1158                 if (!PageHighMem(sg_page(s))) {
1159                         check_for_stack(dev, sg_virt(s));
1160                         check_for_illegal_area(dev, sg_virt(s), sg_dma_len(s));
1161                 }
1162
1163                 add_dma_entry(entry);
1164         }
1165 }
1166 EXPORT_SYMBOL(debug_dma_map_sg);
1167
1168 static int get_nr_mapped_entries(struct device *dev,
1169                                  struct dma_debug_entry *ref)
1170 {
1171         struct dma_debug_entry *entry;
1172         struct hash_bucket *bucket;
1173         unsigned long flags;
1174         int mapped_ents;
1175
1176         bucket       = get_hash_bucket(ref, &flags);
1177         entry        = bucket_find_exact(bucket, ref);
1178         mapped_ents  = 0;
1179
1180         if (entry)
1181                 mapped_ents = entry->sg_mapped_ents;
1182         put_hash_bucket(bucket, &flags);
1183
1184         return mapped_ents;
1185 }
1186
1187 void debug_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
1188                         int nelems, int dir)
1189 {
1190         struct scatterlist *s;
1191         int mapped_ents = 0, i;
1192
1193         if (unlikely(global_disable))
1194                 return;
1195
1196         for_each_sg(sglist, s, nelems, i) {
1197
1198                 struct dma_debug_entry ref = {
1199                         .type           = dma_debug_sg,
1200                         .dev            = dev,
1201                         .paddr          = sg_phys(s),
1202                         .dev_addr       = sg_dma_address(s),
1203                         .size           = sg_dma_len(s),
1204                         .direction      = dir,
1205                         .sg_call_ents   = nelems,
1206                 };
1207
1208                 if (mapped_ents && i >= mapped_ents)
1209                         break;
1210
1211                 if (!i)
1212                         mapped_ents = get_nr_mapped_entries(dev, &ref);
1213
1214                 check_unmap(&ref);
1215         }
1216 }
1217 EXPORT_SYMBOL(debug_dma_unmap_sg);
1218
1219 void debug_dma_alloc_coherent(struct device *dev, size_t size,
1220                               dma_addr_t dma_addr, void *virt)
1221 {
1222         struct dma_debug_entry *entry;
1223
1224         if (unlikely(global_disable))
1225                 return;
1226
1227         if (unlikely(virt == NULL))
1228                 return;
1229
1230         entry = dma_entry_alloc();
1231         if (!entry)
1232                 return;
1233
1234         entry->type      = dma_debug_coherent;
1235         entry->dev       = dev;
1236         entry->paddr     = virt_to_phys(virt);
1237         entry->size      = size;
1238         entry->dev_addr  = dma_addr;
1239         entry->direction = DMA_BIDIRECTIONAL;
1240
1241         add_dma_entry(entry);
1242 }
1243 EXPORT_SYMBOL(debug_dma_alloc_coherent);
1244
1245 void debug_dma_free_coherent(struct device *dev, size_t size,
1246                          void *virt, dma_addr_t addr)
1247 {
1248         struct dma_debug_entry ref = {
1249                 .type           = dma_debug_coherent,
1250                 .dev            = dev,
1251                 .paddr          = virt_to_phys(virt),
1252                 .dev_addr       = addr,
1253                 .size           = size,
1254                 .direction      = DMA_BIDIRECTIONAL,
1255         };
1256
1257         if (unlikely(global_disable))
1258                 return;
1259
1260         check_unmap(&ref);
1261 }
1262 EXPORT_SYMBOL(debug_dma_free_coherent);
1263
1264 void debug_dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_handle,
1265                                    size_t size, int direction)
1266 {
1267         struct dma_debug_entry ref;
1268
1269         if (unlikely(global_disable))
1270                 return;
1271
1272         ref.type         = dma_debug_single;
1273         ref.dev          = dev;
1274         ref.dev_addr     = dma_handle;
1275         ref.size         = size;
1276         ref.direction    = direction;
1277         ref.sg_call_ents = 0;
1278
1279         check_sync(dev, &ref, true);
1280 }
1281 EXPORT_SYMBOL(debug_dma_sync_single_for_cpu);
1282
1283 void debug_dma_sync_single_for_device(struct device *dev,
1284                                       dma_addr_t dma_handle, size_t size,
1285                                       int direction)
1286 {
1287         struct dma_debug_entry ref;
1288
1289         if (unlikely(global_disable))
1290                 return;
1291
1292         ref.type         = dma_debug_single;
1293         ref.dev          = dev;
1294         ref.dev_addr     = dma_handle;
1295         ref.size         = size;
1296         ref.direction    = direction;
1297         ref.sg_call_ents = 0;
1298
1299         check_sync(dev, &ref, false);
1300 }
1301 EXPORT_SYMBOL(debug_dma_sync_single_for_device);
1302
1303 void debug_dma_sync_single_range_for_cpu(struct device *dev,
1304                                          dma_addr_t dma_handle,
1305                                          unsigned long offset, size_t size,
1306                                          int direction)
1307 {
1308         struct dma_debug_entry ref;
1309
1310         if (unlikely(global_disable))
1311                 return;
1312
1313         ref.type         = dma_debug_single;
1314         ref.dev          = dev;
1315         ref.dev_addr     = dma_handle;
1316         ref.size         = offset + size;
1317         ref.direction    = direction;
1318         ref.sg_call_ents = 0;
1319
1320         check_sync(dev, &ref, true);
1321 }
1322 EXPORT_SYMBOL(debug_dma_sync_single_range_for_cpu);
1323
1324 void debug_dma_sync_single_range_for_device(struct device *dev,
1325                                             dma_addr_t dma_handle,
1326                                             unsigned long offset,
1327                                             size_t size, int direction)
1328 {
1329         struct dma_debug_entry ref;
1330
1331         if (unlikely(global_disable))
1332                 return;
1333
1334         ref.type         = dma_debug_single;
1335         ref.dev          = dev;
1336         ref.dev_addr     = dma_handle;
1337         ref.size         = offset + size;
1338         ref.direction    = direction;
1339         ref.sg_call_ents = 0;
1340
1341         check_sync(dev, &ref, false);
1342 }
1343 EXPORT_SYMBOL(debug_dma_sync_single_range_for_device);
1344
1345 void debug_dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
1346                                int nelems, int direction)
1347 {
1348         struct scatterlist *s;
1349         int mapped_ents = 0, i;
1350
1351         if (unlikely(global_disable))
1352                 return;
1353
1354         for_each_sg(sg, s, nelems, i) {
1355
1356                 struct dma_debug_entry ref = {
1357                         .type           = dma_debug_sg,
1358                         .dev            = dev,
1359                         .paddr          = sg_phys(s),
1360                         .dev_addr       = sg_dma_address(s),
1361                         .size           = sg_dma_len(s),
1362                         .direction      = direction,
1363                         .sg_call_ents   = nelems,
1364                 };
1365
1366                 if (!i)
1367                         mapped_ents = get_nr_mapped_entries(dev, &ref);
1368
1369                 if (i >= mapped_ents)
1370                         break;
1371
1372                 check_sync(dev, &ref, true);
1373         }
1374 }
1375 EXPORT_SYMBOL(debug_dma_sync_sg_for_cpu);
1376
1377 void debug_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
1378                                   int nelems, int direction)
1379 {
1380         struct scatterlist *s;
1381         int mapped_ents = 0, i;
1382
1383         if (unlikely(global_disable))
1384                 return;
1385
1386         for_each_sg(sg, s, nelems, i) {
1387
1388                 struct dma_debug_entry ref = {
1389                         .type           = dma_debug_sg,
1390                         .dev            = dev,
1391                         .paddr          = sg_phys(s),
1392                         .dev_addr       = sg_dma_address(s),
1393                         .size           = sg_dma_len(s),
1394                         .direction      = direction,
1395                         .sg_call_ents   = nelems,
1396                 };
1397                 if (!i)
1398                         mapped_ents = get_nr_mapped_entries(dev, &ref);
1399
1400                 if (i >= mapped_ents)
1401                         break;
1402
1403                 check_sync(dev, &ref, false);
1404         }
1405 }
1406 EXPORT_SYMBOL(debug_dma_sync_sg_for_device);
1407
1408 static int __init dma_debug_driver_setup(char *str)
1409 {
1410         int i;
1411
1412         for (i = 0; i < NAME_MAX_LEN - 1; ++i, ++str) {
1413                 current_driver_name[i] = *str;
1414                 if (*str == 0)
1415                         break;
1416         }
1417
1418         if (current_driver_name[0])
1419                 pr_info("DMA-API: enable driver filter for driver [%s]\n",
1420                         current_driver_name);
1421
1422
1423         return 1;
1424 }
1425 __setup("dma_debug_driver=", dma_debug_driver_setup);