Merge branch 'samsung/exynos5' into next/soc2
[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/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 #define DMA_DEBUG_STACKTRACE_ENTRIES 5
49
50 struct dma_debug_entry {
51         struct list_head list;
52         struct device    *dev;
53         int              type;
54         phys_addr_t      paddr;
55         u64              dev_addr;
56         u64              size;
57         int              direction;
58         int              sg_call_ents;
59         int              sg_mapped_ents;
60 #ifdef CONFIG_STACKTRACE
61         struct           stack_trace stacktrace;
62         unsigned long    st_entries[DMA_DEBUG_STACKTRACE_ENTRIES];
63 #endif
64 };
65
66 typedef bool (*match_fn)(struct dma_debug_entry *, struct dma_debug_entry *);
67
68 struct hash_bucket {
69         struct list_head list;
70         spinlock_t lock;
71 } ____cacheline_aligned_in_smp;
72
73 /* Hash list to save the allocated dma addresses */
74 static struct hash_bucket dma_entry_hash[HASH_SIZE];
75 /* List of pre-allocated dma_debug_entry's */
76 static LIST_HEAD(free_entries);
77 /* Lock for the list above */
78 static DEFINE_SPINLOCK(free_entries_lock);
79
80 /* Global disable flag - will be set in case of an error */
81 static bool global_disable __read_mostly;
82
83 /* Global error count */
84 static u32 error_count;
85
86 /* Global error show enable*/
87 static u32 show_all_errors __read_mostly;
88 /* Number of errors to show */
89 static u32 show_num_errors = 1;
90
91 static u32 num_free_entries;
92 static u32 min_free_entries;
93 static u32 nr_total_entries;
94
95 /* number of preallocated entries requested by kernel cmdline */
96 static u32 req_entries;
97
98 /* debugfs dentry's for the stuff above */
99 static struct dentry *dma_debug_dent        __read_mostly;
100 static struct dentry *global_disable_dent   __read_mostly;
101 static struct dentry *error_count_dent      __read_mostly;
102 static struct dentry *show_all_errors_dent  __read_mostly;
103 static struct dentry *show_num_errors_dent  __read_mostly;
104 static struct dentry *num_free_entries_dent __read_mostly;
105 static struct dentry *min_free_entries_dent __read_mostly;
106 static struct dentry *filter_dent           __read_mostly;
107
108 /* per-driver filter related state */
109
110 #define NAME_MAX_LEN    64
111
112 static char                  current_driver_name[NAME_MAX_LEN] __read_mostly;
113 static struct device_driver *current_driver                    __read_mostly;
114
115 static DEFINE_RWLOCK(driver_name_lock);
116
117 static const char *type2name[4] = { "single", "page",
118                                     "scather-gather", "coherent" };
119
120 static const char *dir2name[4] = { "DMA_BIDIRECTIONAL", "DMA_TO_DEVICE",
121                                    "DMA_FROM_DEVICE", "DMA_NONE" };
122
123 /* little merge helper - remove it after the merge window */
124 #ifndef BUS_NOTIFY_UNBOUND_DRIVER
125 #define BUS_NOTIFY_UNBOUND_DRIVER 0x0005
126 #endif
127
128 /*
129  * The access to some variables in this macro is racy. We can't use atomic_t
130  * here because all these variables are exported to debugfs. Some of them even
131  * writeable. This is also the reason why a lock won't help much. But anyway,
132  * the races are no big deal. Here is why:
133  *
134  *   error_count: the addition is racy, but the worst thing that can happen is
135  *                that we don't count some errors
136  *   show_num_errors: the subtraction is racy. Also no big deal because in
137  *                    worst case this will result in one warning more in the
138  *                    system log than the user configured. This variable is
139  *                    writeable via debugfs.
140  */
141 static inline void dump_entry_trace(struct dma_debug_entry *entry)
142 {
143 #ifdef CONFIG_STACKTRACE
144         if (entry) {
145                 pr_warning("Mapped at:\n");
146                 print_stack_trace(&entry->stacktrace, 0);
147         }
148 #endif
149 }
150
151 static bool driver_filter(struct device *dev)
152 {
153         struct device_driver *drv;
154         unsigned long flags;
155         bool ret;
156
157         /* driver filter off */
158         if (likely(!current_driver_name[0]))
159                 return true;
160
161         /* driver filter on and initialized */
162         if (current_driver && dev && dev->driver == current_driver)
163                 return true;
164
165         /* driver filter on, but we can't filter on a NULL device... */
166         if (!dev)
167                 return false;
168
169         if (current_driver || !current_driver_name[0])
170                 return false;
171
172         /* driver filter on but not yet initialized */
173         drv = dev->driver;
174         if (!drv)
175                 return false;
176
177         /* lock to protect against change of current_driver_name */
178         read_lock_irqsave(&driver_name_lock, flags);
179
180         ret = false;
181         if (drv->name &&
182             strncmp(current_driver_name, drv->name, NAME_MAX_LEN - 1) == 0) {
183                 current_driver = drv;
184                 ret = true;
185         }
186
187         read_unlock_irqrestore(&driver_name_lock, flags);
188
189         return ret;
190 }
191
192 #define err_printk(dev, entry, format, arg...) do {                     \
193                 error_count += 1;                                       \
194                 if (driver_filter(dev) &&                               \
195                     (show_all_errors || show_num_errors > 0)) {         \
196                         WARN(1, "%s %s: " format,                       \
197                              dev ? dev_driver_string(dev) : "NULL",     \
198                              dev ? dev_name(dev) : "NULL", ## arg);     \
199                         dump_entry_trace(entry);                        \
200                 }                                                       \
201                 if (!show_all_errors && show_num_errors > 0)            \
202                         show_num_errors -= 1;                           \
203         } while (0);
204
205 /*
206  * Hash related functions
207  *
208  * Every DMA-API request is saved into a struct dma_debug_entry. To
209  * have quick access to these structs they are stored into a hash.
210  */
211 static int hash_fn(struct dma_debug_entry *entry)
212 {
213         /*
214          * Hash function is based on the dma address.
215          * We use bits 20-27 here as the index into the hash
216          */
217         return (entry->dev_addr >> HASH_FN_SHIFT) & HASH_FN_MASK;
218 }
219
220 /*
221  * Request exclusive access to a hash bucket for a given dma_debug_entry.
222  */
223 static struct hash_bucket *get_hash_bucket(struct dma_debug_entry *entry,
224                                            unsigned long *flags)
225 {
226         int idx = hash_fn(entry);
227         unsigned long __flags;
228
229         spin_lock_irqsave(&dma_entry_hash[idx].lock, __flags);
230         *flags = __flags;
231         return &dma_entry_hash[idx];
232 }
233
234 /*
235  * Give up exclusive access to the hash bucket
236  */
237 static void put_hash_bucket(struct hash_bucket *bucket,
238                             unsigned long *flags)
239 {
240         unsigned long __flags = *flags;
241
242         spin_unlock_irqrestore(&bucket->lock, __flags);
243 }
244
245 static bool exact_match(struct dma_debug_entry *a, struct dma_debug_entry *b)
246 {
247         return ((a->dev_addr == b->dev_addr) &&
248                 (a->dev == b->dev)) ? true : false;
249 }
250
251 static bool containing_match(struct dma_debug_entry *a,
252                              struct dma_debug_entry *b)
253 {
254         if (a->dev != b->dev)
255                 return false;
256
257         if ((b->dev_addr <= a->dev_addr) &&
258             ((b->dev_addr + b->size) >= (a->dev_addr + a->size)))
259                 return true;
260
261         return false;
262 }
263
264 /*
265  * Search a given entry in the hash bucket list
266  */
267 static struct dma_debug_entry *__hash_bucket_find(struct hash_bucket *bucket,
268                                                   struct dma_debug_entry *ref,
269                                                   match_fn match)
270 {
271         struct dma_debug_entry *entry, *ret = NULL;
272         int matches = 0, match_lvl, last_lvl = 0;
273
274         list_for_each_entry(entry, &bucket->list, list) {
275                 if (!match(ref, entry))
276                         continue;
277
278                 /*
279                  * Some drivers map the same physical address multiple
280                  * times. Without a hardware IOMMU this results in the
281                  * same device addresses being put into the dma-debug
282                  * hash multiple times too. This can result in false
283                  * positives being reported. Therefore we implement a
284                  * best-fit algorithm here which returns the entry from
285                  * the hash which fits best to the reference value
286                  * instead of the first-fit.
287                  */
288                 matches += 1;
289                 match_lvl = 0;
290                 entry->size         == ref->size         ? ++match_lvl : 0;
291                 entry->type         == ref->type         ? ++match_lvl : 0;
292                 entry->direction    == ref->direction    ? ++match_lvl : 0;
293                 entry->sg_call_ents == ref->sg_call_ents ? ++match_lvl : 0;
294
295                 if (match_lvl == 4) {
296                         /* perfect-fit - return the result */
297                         return entry;
298                 } else if (match_lvl > last_lvl) {
299                         /*
300                          * We found an entry that fits better then the
301                          * previous one
302                          */
303                         last_lvl = match_lvl;
304                         ret      = entry;
305                 }
306         }
307
308         /*
309          * If we have multiple matches but no perfect-fit, just return
310          * NULL.
311          */
312         ret = (matches == 1) ? ret : NULL;
313
314         return ret;
315 }
316
317 static struct dma_debug_entry *bucket_find_exact(struct hash_bucket *bucket,
318                                                  struct dma_debug_entry *ref)
319 {
320         return __hash_bucket_find(bucket, ref, exact_match);
321 }
322
323 static struct dma_debug_entry *bucket_find_contain(struct hash_bucket **bucket,
324                                                    struct dma_debug_entry *ref,
325                                                    unsigned long *flags)
326 {
327
328         unsigned int max_range = dma_get_max_seg_size(ref->dev);
329         struct dma_debug_entry *entry, index = *ref;
330         unsigned int range = 0;
331
332         while (range <= max_range) {
333                 entry = __hash_bucket_find(*bucket, &index, containing_match);
334
335                 if (entry)
336                         return entry;
337
338                 /*
339                  * Nothing found, go back a hash bucket
340                  */
341                 put_hash_bucket(*bucket, flags);
342                 range          += (1 << HASH_FN_SHIFT);
343                 index.dev_addr -= (1 << HASH_FN_SHIFT);
344                 *bucket = get_hash_bucket(&index, flags);
345         }
346
347         return NULL;
348 }
349
350 /*
351  * Add an entry to a hash bucket
352  */
353 static void hash_bucket_add(struct hash_bucket *bucket,
354                             struct dma_debug_entry *entry)
355 {
356         list_add_tail(&entry->list, &bucket->list);
357 }
358
359 /*
360  * Remove entry from a hash bucket list
361  */
362 static void hash_bucket_del(struct dma_debug_entry *entry)
363 {
364         list_del(&entry->list);
365 }
366
367 /*
368  * Dump mapping entries for debugging purposes
369  */
370 void debug_dma_dump_mappings(struct device *dev)
371 {
372         int idx;
373
374         for (idx = 0; idx < HASH_SIZE; idx++) {
375                 struct hash_bucket *bucket = &dma_entry_hash[idx];
376                 struct dma_debug_entry *entry;
377                 unsigned long flags;
378
379                 spin_lock_irqsave(&bucket->lock, flags);
380
381                 list_for_each_entry(entry, &bucket->list, list) {
382                         if (!dev || dev == entry->dev) {
383                                 dev_info(entry->dev,
384                                          "%s idx %d P=%Lx D=%Lx L=%Lx %s\n",
385                                          type2name[entry->type], idx,
386                                          (unsigned long long)entry->paddr,
387                                          entry->dev_addr, entry->size,
388                                          dir2name[entry->direction]);
389                         }
390                 }
391
392                 spin_unlock_irqrestore(&bucket->lock, flags);
393         }
394 }
395 EXPORT_SYMBOL(debug_dma_dump_mappings);
396
397 /*
398  * Wrapper function for adding an entry to the hash.
399  * This function takes care of locking itself.
400  */
401 static void add_dma_entry(struct dma_debug_entry *entry)
402 {
403         struct hash_bucket *bucket;
404         unsigned long flags;
405
406         bucket = get_hash_bucket(entry, &flags);
407         hash_bucket_add(bucket, entry);
408         put_hash_bucket(bucket, &flags);
409 }
410
411 static struct dma_debug_entry *__dma_entry_alloc(void)
412 {
413         struct dma_debug_entry *entry;
414
415         entry = list_entry(free_entries.next, struct dma_debug_entry, list);
416         list_del(&entry->list);
417         memset(entry, 0, sizeof(*entry));
418
419         num_free_entries -= 1;
420         if (num_free_entries < min_free_entries)
421                 min_free_entries = num_free_entries;
422
423         return entry;
424 }
425
426 /* struct dma_entry allocator
427  *
428  * The next two functions implement the allocator for
429  * struct dma_debug_entries.
430  */
431 static struct dma_debug_entry *dma_entry_alloc(void)
432 {
433         struct dma_debug_entry *entry = NULL;
434         unsigned long flags;
435
436         spin_lock_irqsave(&free_entries_lock, flags);
437
438         if (list_empty(&free_entries)) {
439                 pr_err("DMA-API: debugging out of memory - disabling\n");
440                 global_disable = true;
441                 goto out;
442         }
443
444         entry = __dma_entry_alloc();
445
446 #ifdef CONFIG_STACKTRACE
447         entry->stacktrace.max_entries = DMA_DEBUG_STACKTRACE_ENTRIES;
448         entry->stacktrace.entries = entry->st_entries;
449         entry->stacktrace.skip = 2;
450         save_stack_trace(&entry->stacktrace);
451 #endif
452
453 out:
454         spin_unlock_irqrestore(&free_entries_lock, flags);
455
456         return entry;
457 }
458
459 static void dma_entry_free(struct dma_debug_entry *entry)
460 {
461         unsigned long flags;
462
463         /*
464          * add to beginning of the list - this way the entries are
465          * more likely cache hot when they are reallocated.
466          */
467         spin_lock_irqsave(&free_entries_lock, flags);
468         list_add(&entry->list, &free_entries);
469         num_free_entries += 1;
470         spin_unlock_irqrestore(&free_entries_lock, flags);
471 }
472
473 int dma_debug_resize_entries(u32 num_entries)
474 {
475         int i, delta, ret = 0;
476         unsigned long flags;
477         struct dma_debug_entry *entry;
478         LIST_HEAD(tmp);
479
480         spin_lock_irqsave(&free_entries_lock, flags);
481
482         if (nr_total_entries < num_entries) {
483                 delta = num_entries - nr_total_entries;
484
485                 spin_unlock_irqrestore(&free_entries_lock, flags);
486
487                 for (i = 0; i < delta; i++) {
488                         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
489                         if (!entry)
490                                 break;
491
492                         list_add_tail(&entry->list, &tmp);
493                 }
494
495                 spin_lock_irqsave(&free_entries_lock, flags);
496
497                 list_splice(&tmp, &free_entries);
498                 nr_total_entries += i;
499                 num_free_entries += i;
500         } else {
501                 delta = nr_total_entries - num_entries;
502
503                 for (i = 0; i < delta && !list_empty(&free_entries); i++) {
504                         entry = __dma_entry_alloc();
505                         kfree(entry);
506                 }
507
508                 nr_total_entries -= i;
509         }
510
511         if (nr_total_entries != num_entries)
512                 ret = 1;
513
514         spin_unlock_irqrestore(&free_entries_lock, flags);
515
516         return ret;
517 }
518 EXPORT_SYMBOL(dma_debug_resize_entries);
519
520 /*
521  * DMA-API debugging init code
522  *
523  * The init code does two things:
524  *   1. Initialize core data structures
525  *   2. Preallocate a given number of dma_debug_entry structs
526  */
527
528 static int prealloc_memory(u32 num_entries)
529 {
530         struct dma_debug_entry *entry, *next_entry;
531         int i;
532
533         for (i = 0; i < num_entries; ++i) {
534                 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
535                 if (!entry)
536                         goto out_err;
537
538                 list_add_tail(&entry->list, &free_entries);
539         }
540
541         num_free_entries = num_entries;
542         min_free_entries = num_entries;
543
544         pr_info("DMA-API: preallocated %d debug entries\n", num_entries);
545
546         return 0;
547
548 out_err:
549
550         list_for_each_entry_safe(entry, next_entry, &free_entries, list) {
551                 list_del(&entry->list);
552                 kfree(entry);
553         }
554
555         return -ENOMEM;
556 }
557
558 static ssize_t filter_read(struct file *file, char __user *user_buf,
559                            size_t count, loff_t *ppos)
560 {
561         char buf[NAME_MAX_LEN + 1];
562         unsigned long flags;
563         int len;
564
565         if (!current_driver_name[0])
566                 return 0;
567
568         /*
569          * We can't copy to userspace directly because current_driver_name can
570          * only be read under the driver_name_lock with irqs disabled. So
571          * create a temporary copy first.
572          */
573         read_lock_irqsave(&driver_name_lock, flags);
574         len = scnprintf(buf, NAME_MAX_LEN + 1, "%s\n", current_driver_name);
575         read_unlock_irqrestore(&driver_name_lock, flags);
576
577         return simple_read_from_buffer(user_buf, count, ppos, buf, len);
578 }
579
580 static ssize_t filter_write(struct file *file, const char __user *userbuf,
581                             size_t count, loff_t *ppos)
582 {
583         char buf[NAME_MAX_LEN];
584         unsigned long flags;
585         size_t len;
586         int i;
587
588         /*
589          * We can't copy from userspace directly. Access to
590          * current_driver_name is protected with a write_lock with irqs
591          * disabled. Since copy_from_user can fault and may sleep we
592          * need to copy to temporary buffer first
593          */
594         len = min(count, (size_t)(NAME_MAX_LEN - 1));
595         if (copy_from_user(buf, userbuf, len))
596                 return -EFAULT;
597
598         buf[len] = 0;
599
600         write_lock_irqsave(&driver_name_lock, flags);
601
602         /*
603          * Now handle the string we got from userspace very carefully.
604          * The rules are:
605          *         - only use the first token we got
606          *         - token delimiter is everything looking like a space
607          *           character (' ', '\n', '\t' ...)
608          *
609          */
610         if (!isalnum(buf[0])) {
611                 /*
612                  * If the first character userspace gave us is not
613                  * alphanumerical then assume the filter should be
614                  * switched off.
615                  */
616                 if (current_driver_name[0])
617                         pr_info("DMA-API: switching off dma-debug driver filter\n");
618                 current_driver_name[0] = 0;
619                 current_driver = NULL;
620                 goto out_unlock;
621         }
622
623         /*
624          * Now parse out the first token and use it as the name for the
625          * driver to filter for.
626          */
627         for (i = 0; i < NAME_MAX_LEN - 1; ++i) {
628                 current_driver_name[i] = buf[i];
629                 if (isspace(buf[i]) || buf[i] == ' ' || buf[i] == 0)
630                         break;
631         }
632         current_driver_name[i] = 0;
633         current_driver = NULL;
634
635         pr_info("DMA-API: enable driver filter for driver [%s]\n",
636                 current_driver_name);
637
638 out_unlock:
639         write_unlock_irqrestore(&driver_name_lock, flags);
640
641         return count;
642 }
643
644 static const struct file_operations filter_fops = {
645         .read  = filter_read,
646         .write = filter_write,
647         .llseek = default_llseek,
648 };
649
650 static int dma_debug_fs_init(void)
651 {
652         dma_debug_dent = debugfs_create_dir("dma-api", NULL);
653         if (!dma_debug_dent) {
654                 pr_err("DMA-API: can not create debugfs directory\n");
655                 return -ENOMEM;
656         }
657
658         global_disable_dent = debugfs_create_bool("disabled", 0444,
659                         dma_debug_dent,
660                         (u32 *)&global_disable);
661         if (!global_disable_dent)
662                 goto out_err;
663
664         error_count_dent = debugfs_create_u32("error_count", 0444,
665                         dma_debug_dent, &error_count);
666         if (!error_count_dent)
667                 goto out_err;
668
669         show_all_errors_dent = debugfs_create_u32("all_errors", 0644,
670                         dma_debug_dent,
671                         &show_all_errors);
672         if (!show_all_errors_dent)
673                 goto out_err;
674
675         show_num_errors_dent = debugfs_create_u32("num_errors", 0644,
676                         dma_debug_dent,
677                         &show_num_errors);
678         if (!show_num_errors_dent)
679                 goto out_err;
680
681         num_free_entries_dent = debugfs_create_u32("num_free_entries", 0444,
682                         dma_debug_dent,
683                         &num_free_entries);
684         if (!num_free_entries_dent)
685                 goto out_err;
686
687         min_free_entries_dent = debugfs_create_u32("min_free_entries", 0444,
688                         dma_debug_dent,
689                         &min_free_entries);
690         if (!min_free_entries_dent)
691                 goto out_err;
692
693         filter_dent = debugfs_create_file("driver_filter", 0644,
694                                           dma_debug_dent, NULL, &filter_fops);
695         if (!filter_dent)
696                 goto out_err;
697
698         return 0;
699
700 out_err:
701         debugfs_remove_recursive(dma_debug_dent);
702
703         return -ENOMEM;
704 }
705
706 static int device_dma_allocations(struct device *dev, struct dma_debug_entry **out_entry)
707 {
708         struct dma_debug_entry *entry;
709         unsigned long flags;
710         int count = 0, i;
711
712         local_irq_save(flags);
713
714         for (i = 0; i < HASH_SIZE; ++i) {
715                 spin_lock(&dma_entry_hash[i].lock);
716                 list_for_each_entry(entry, &dma_entry_hash[i].list, list) {
717                         if (entry->dev == dev) {
718                                 count += 1;
719                                 *out_entry = entry;
720                         }
721                 }
722                 spin_unlock(&dma_entry_hash[i].lock);
723         }
724
725         local_irq_restore(flags);
726
727         return count;
728 }
729
730 static int dma_debug_device_change(struct notifier_block *nb, unsigned long action, void *data)
731 {
732         struct device *dev = data;
733         struct dma_debug_entry *uninitialized_var(entry);
734         int count;
735
736         if (global_disable)
737                 return 0;
738
739         switch (action) {
740         case BUS_NOTIFY_UNBOUND_DRIVER:
741                 count = device_dma_allocations(dev, &entry);
742                 if (count == 0)
743                         break;
744                 err_printk(dev, entry, "DMA-API: device driver has pending "
745                                 "DMA allocations while released from device "
746                                 "[count=%d]\n"
747                                 "One of leaked entries details: "
748                                 "[device address=0x%016llx] [size=%llu bytes] "
749                                 "[mapped with %s] [mapped as %s]\n",
750                         count, entry->dev_addr, entry->size,
751                         dir2name[entry->direction], type2name[entry->type]);
752                 break;
753         default:
754                 break;
755         }
756
757         return 0;
758 }
759
760 void dma_debug_add_bus(struct bus_type *bus)
761 {
762         struct notifier_block *nb;
763
764         if (global_disable)
765                 return;
766
767         nb = kzalloc(sizeof(struct notifier_block), GFP_KERNEL);
768         if (nb == NULL) {
769                 pr_err("dma_debug_add_bus: out of memory\n");
770                 return;
771         }
772
773         nb->notifier_call = dma_debug_device_change;
774
775         bus_register_notifier(bus, nb);
776 }
777
778 /*
779  * Let the architectures decide how many entries should be preallocated.
780  */
781 void dma_debug_init(u32 num_entries)
782 {
783         int i;
784
785         if (global_disable)
786                 return;
787
788         for (i = 0; i < HASH_SIZE; ++i) {
789                 INIT_LIST_HEAD(&dma_entry_hash[i].list);
790                 spin_lock_init(&dma_entry_hash[i].lock);
791         }
792
793         if (dma_debug_fs_init() != 0) {
794                 pr_err("DMA-API: error creating debugfs entries - disabling\n");
795                 global_disable = true;
796
797                 return;
798         }
799
800         if (req_entries)
801                 num_entries = req_entries;
802
803         if (prealloc_memory(num_entries) != 0) {
804                 pr_err("DMA-API: debugging out of memory error - disabled\n");
805                 global_disable = true;
806
807                 return;
808         }
809
810         nr_total_entries = num_free_entries;
811
812         pr_info("DMA-API: debugging enabled by kernel config\n");
813 }
814
815 static __init int dma_debug_cmdline(char *str)
816 {
817         if (!str)
818                 return -EINVAL;
819
820         if (strncmp(str, "off", 3) == 0) {
821                 pr_info("DMA-API: debugging disabled on kernel command line\n");
822                 global_disable = true;
823         }
824
825         return 0;
826 }
827
828 static __init int dma_debug_entries_cmdline(char *str)
829 {
830         int res;
831
832         if (!str)
833                 return -EINVAL;
834
835         res = get_option(&str, &req_entries);
836
837         if (!res)
838                 req_entries = 0;
839
840         return 0;
841 }
842
843 __setup("dma_debug=", dma_debug_cmdline);
844 __setup("dma_debug_entries=", dma_debug_entries_cmdline);
845
846 static void check_unmap(struct dma_debug_entry *ref)
847 {
848         struct dma_debug_entry *entry;
849         struct hash_bucket *bucket;
850         unsigned long flags;
851
852         if (dma_mapping_error(ref->dev, ref->dev_addr)) {
853                 err_printk(ref->dev, NULL, "DMA-API: device driver tries "
854                            "to free an invalid DMA memory address\n");
855                 return;
856         }
857
858         bucket = get_hash_bucket(ref, &flags);
859         entry = bucket_find_exact(bucket, ref);
860
861         if (!entry) {
862                 err_printk(ref->dev, NULL, "DMA-API: device driver tries "
863                            "to free DMA memory it has not allocated "
864                            "[device address=0x%016llx] [size=%llu bytes]\n",
865                            ref->dev_addr, ref->size);
866                 goto out;
867         }
868
869         if (ref->size != entry->size) {
870                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
871                            "DMA memory with different size "
872                            "[device address=0x%016llx] [map size=%llu bytes] "
873                            "[unmap size=%llu bytes]\n",
874                            ref->dev_addr, entry->size, ref->size);
875         }
876
877         if (ref->type != entry->type) {
878                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
879                            "DMA memory with wrong function "
880                            "[device address=0x%016llx] [size=%llu bytes] "
881                            "[mapped as %s] [unmapped as %s]\n",
882                            ref->dev_addr, ref->size,
883                            type2name[entry->type], type2name[ref->type]);
884         } else if ((entry->type == dma_debug_coherent) &&
885                    (ref->paddr != entry->paddr)) {
886                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
887                            "DMA memory with different CPU address "
888                            "[device address=0x%016llx] [size=%llu bytes] "
889                            "[cpu alloc address=0x%016llx] "
890                            "[cpu free address=0x%016llx]",
891                            ref->dev_addr, ref->size,
892                            (unsigned long long)entry->paddr,
893                            (unsigned long long)ref->paddr);
894         }
895
896         if (ref->sg_call_ents && ref->type == dma_debug_sg &&
897             ref->sg_call_ents != entry->sg_call_ents) {
898                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
899                            "DMA sg list with different entry count "
900                            "[map count=%d] [unmap count=%d]\n",
901                            entry->sg_call_ents, ref->sg_call_ents);
902         }
903
904         /*
905          * This may be no bug in reality - but most implementations of the
906          * DMA API don't handle this properly, so check for it here
907          */
908         if (ref->direction != entry->direction) {
909                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
910                            "DMA memory with different direction "
911                            "[device address=0x%016llx] [size=%llu bytes] "
912                            "[mapped with %s] [unmapped with %s]\n",
913                            ref->dev_addr, ref->size,
914                            dir2name[entry->direction],
915                            dir2name[ref->direction]);
916         }
917
918         hash_bucket_del(entry);
919         dma_entry_free(entry);
920
921 out:
922         put_hash_bucket(bucket, &flags);
923 }
924
925 static void check_for_stack(struct device *dev, void *addr)
926 {
927         if (object_is_on_stack(addr))
928                 err_printk(dev, NULL, "DMA-API: device driver maps memory from"
929                                 "stack [addr=%p]\n", addr);
930 }
931
932 static inline bool overlap(void *addr, unsigned long len, void *start, void *end)
933 {
934         unsigned long a1 = (unsigned long)addr;
935         unsigned long b1 = a1 + len;
936         unsigned long a2 = (unsigned long)start;
937         unsigned long b2 = (unsigned long)end;
938
939         return !(b1 <= a2 || a1 >= b2);
940 }
941
942 static void check_for_illegal_area(struct device *dev, void *addr, unsigned long len)
943 {
944         if (overlap(addr, len, _text, _etext) ||
945             overlap(addr, len, __start_rodata, __end_rodata))
946                 err_printk(dev, NULL, "DMA-API: device driver maps memory from kernel text or rodata [addr=%p] [len=%lu]\n", addr, len);
947 }
948
949 static void check_sync(struct device *dev,
950                        struct dma_debug_entry *ref,
951                        bool to_cpu)
952 {
953         struct dma_debug_entry *entry;
954         struct hash_bucket *bucket;
955         unsigned long flags;
956
957         bucket = get_hash_bucket(ref, &flags);
958
959         entry = bucket_find_contain(&bucket, ref, &flags);
960
961         if (!entry) {
962                 err_printk(dev, NULL, "DMA-API: device driver tries "
963                                 "to sync DMA memory it has not allocated "
964                                 "[device address=0x%016llx] [size=%llu bytes]\n",
965                                 (unsigned long long)ref->dev_addr, ref->size);
966                 goto out;
967         }
968
969         if (ref->size > entry->size) {
970                 err_printk(dev, entry, "DMA-API: device driver syncs"
971                                 " DMA memory outside allocated range "
972                                 "[device address=0x%016llx] "
973                                 "[allocation size=%llu bytes] "
974                                 "[sync offset+size=%llu]\n",
975                                 entry->dev_addr, entry->size,
976                                 ref->size);
977         }
978
979         if (entry->direction == DMA_BIDIRECTIONAL)
980                 goto out;
981
982         if (ref->direction != entry->direction) {
983                 err_printk(dev, entry, "DMA-API: device driver syncs "
984                                 "DMA memory with different direction "
985                                 "[device address=0x%016llx] [size=%llu bytes] "
986                                 "[mapped with %s] [synced with %s]\n",
987                                 (unsigned long long)ref->dev_addr, entry->size,
988                                 dir2name[entry->direction],
989                                 dir2name[ref->direction]);
990         }
991
992         if (to_cpu && !(entry->direction == DMA_FROM_DEVICE) &&
993                       !(ref->direction == DMA_TO_DEVICE))
994                 err_printk(dev, entry, "DMA-API: device driver syncs "
995                                 "device read-only DMA memory for cpu "
996                                 "[device address=0x%016llx] [size=%llu bytes] "
997                                 "[mapped with %s] [synced with %s]\n",
998                                 (unsigned long long)ref->dev_addr, entry->size,
999                                 dir2name[entry->direction],
1000                                 dir2name[ref->direction]);
1001
1002         if (!to_cpu && !(entry->direction == DMA_TO_DEVICE) &&
1003                        !(ref->direction == DMA_FROM_DEVICE))
1004                 err_printk(dev, entry, "DMA-API: device driver syncs "
1005                                 "device write-only DMA memory to device "
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 out:
1013         put_hash_bucket(bucket, &flags);
1014 }
1015
1016 void debug_dma_map_page(struct device *dev, struct page *page, size_t offset,
1017                         size_t size, int direction, dma_addr_t dma_addr,
1018                         bool map_single)
1019 {
1020         struct dma_debug_entry *entry;
1021
1022         if (unlikely(global_disable))
1023                 return;
1024
1025         if (unlikely(dma_mapping_error(dev, dma_addr)))
1026                 return;
1027
1028         entry = dma_entry_alloc();
1029         if (!entry)
1030                 return;
1031
1032         entry->dev       = dev;
1033         entry->type      = dma_debug_page;
1034         entry->paddr     = page_to_phys(page) + offset;
1035         entry->dev_addr  = dma_addr;
1036         entry->size      = size;
1037         entry->direction = direction;
1038
1039         if (map_single)
1040                 entry->type = dma_debug_single;
1041
1042         if (!PageHighMem(page)) {
1043                 void *addr = page_address(page) + offset;
1044
1045                 check_for_stack(dev, addr);
1046                 check_for_illegal_area(dev, addr, size);
1047         }
1048
1049         add_dma_entry(entry);
1050 }
1051 EXPORT_SYMBOL(debug_dma_map_page);
1052
1053 void debug_dma_unmap_page(struct device *dev, dma_addr_t addr,
1054                           size_t size, int direction, bool map_single)
1055 {
1056         struct dma_debug_entry ref = {
1057                 .type           = dma_debug_page,
1058                 .dev            = dev,
1059                 .dev_addr       = addr,
1060                 .size           = size,
1061                 .direction      = direction,
1062         };
1063
1064         if (unlikely(global_disable))
1065                 return;
1066
1067         if (map_single)
1068                 ref.type = dma_debug_single;
1069
1070         check_unmap(&ref);
1071 }
1072 EXPORT_SYMBOL(debug_dma_unmap_page);
1073
1074 void debug_dma_map_sg(struct device *dev, struct scatterlist *sg,
1075                       int nents, int mapped_ents, int direction)
1076 {
1077         struct dma_debug_entry *entry;
1078         struct scatterlist *s;
1079         int i;
1080
1081         if (unlikely(global_disable))
1082                 return;
1083
1084         for_each_sg(sg, s, mapped_ents, i) {
1085                 entry = dma_entry_alloc();
1086                 if (!entry)
1087                         return;
1088
1089                 entry->type           = dma_debug_sg;
1090                 entry->dev            = dev;
1091                 entry->paddr          = sg_phys(s);
1092                 entry->size           = sg_dma_len(s);
1093                 entry->dev_addr       = sg_dma_address(s);
1094                 entry->direction      = direction;
1095                 entry->sg_call_ents   = nents;
1096                 entry->sg_mapped_ents = mapped_ents;
1097
1098                 if (!PageHighMem(sg_page(s))) {
1099                         check_for_stack(dev, sg_virt(s));
1100                         check_for_illegal_area(dev, sg_virt(s), sg_dma_len(s));
1101                 }
1102
1103                 add_dma_entry(entry);
1104         }
1105 }
1106 EXPORT_SYMBOL(debug_dma_map_sg);
1107
1108 static int get_nr_mapped_entries(struct device *dev,
1109                                  struct dma_debug_entry *ref)
1110 {
1111         struct dma_debug_entry *entry;
1112         struct hash_bucket *bucket;
1113         unsigned long flags;
1114         int mapped_ents;
1115
1116         bucket       = get_hash_bucket(ref, &flags);
1117         entry        = bucket_find_exact(bucket, ref);
1118         mapped_ents  = 0;
1119
1120         if (entry)
1121                 mapped_ents = entry->sg_mapped_ents;
1122         put_hash_bucket(bucket, &flags);
1123
1124         return mapped_ents;
1125 }
1126
1127 void debug_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
1128                         int nelems, int dir)
1129 {
1130         struct scatterlist *s;
1131         int mapped_ents = 0, i;
1132
1133         if (unlikely(global_disable))
1134                 return;
1135
1136         for_each_sg(sglist, s, nelems, i) {
1137
1138                 struct dma_debug_entry ref = {
1139                         .type           = dma_debug_sg,
1140                         .dev            = dev,
1141                         .paddr          = sg_phys(s),
1142                         .dev_addr       = sg_dma_address(s),
1143                         .size           = sg_dma_len(s),
1144                         .direction      = dir,
1145                         .sg_call_ents   = nelems,
1146                 };
1147
1148                 if (mapped_ents && i >= mapped_ents)
1149                         break;
1150
1151                 if (!i)
1152                         mapped_ents = get_nr_mapped_entries(dev, &ref);
1153
1154                 check_unmap(&ref);
1155         }
1156 }
1157 EXPORT_SYMBOL(debug_dma_unmap_sg);
1158
1159 void debug_dma_alloc_coherent(struct device *dev, size_t size,
1160                               dma_addr_t dma_addr, void *virt)
1161 {
1162         struct dma_debug_entry *entry;
1163
1164         if (unlikely(global_disable))
1165                 return;
1166
1167         if (unlikely(virt == NULL))
1168                 return;
1169
1170         entry = dma_entry_alloc();
1171         if (!entry)
1172                 return;
1173
1174         entry->type      = dma_debug_coherent;
1175         entry->dev       = dev;
1176         entry->paddr     = virt_to_phys(virt);
1177         entry->size      = size;
1178         entry->dev_addr  = dma_addr;
1179         entry->direction = DMA_BIDIRECTIONAL;
1180
1181         add_dma_entry(entry);
1182 }
1183 EXPORT_SYMBOL(debug_dma_alloc_coherent);
1184
1185 void debug_dma_free_coherent(struct device *dev, size_t size,
1186                          void *virt, dma_addr_t addr)
1187 {
1188         struct dma_debug_entry ref = {
1189                 .type           = dma_debug_coherent,
1190                 .dev            = dev,
1191                 .paddr          = virt_to_phys(virt),
1192                 .dev_addr       = addr,
1193                 .size           = size,
1194                 .direction      = DMA_BIDIRECTIONAL,
1195         };
1196
1197         if (unlikely(global_disable))
1198                 return;
1199
1200         check_unmap(&ref);
1201 }
1202 EXPORT_SYMBOL(debug_dma_free_coherent);
1203
1204 void debug_dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_handle,
1205                                    size_t size, int direction)
1206 {
1207         struct dma_debug_entry ref;
1208
1209         if (unlikely(global_disable))
1210                 return;
1211
1212         ref.type         = dma_debug_single;
1213         ref.dev          = dev;
1214         ref.dev_addr     = dma_handle;
1215         ref.size         = size;
1216         ref.direction    = direction;
1217         ref.sg_call_ents = 0;
1218
1219         check_sync(dev, &ref, true);
1220 }
1221 EXPORT_SYMBOL(debug_dma_sync_single_for_cpu);
1222
1223 void debug_dma_sync_single_for_device(struct device *dev,
1224                                       dma_addr_t dma_handle, size_t size,
1225                                       int direction)
1226 {
1227         struct dma_debug_entry ref;
1228
1229         if (unlikely(global_disable))
1230                 return;
1231
1232         ref.type         = dma_debug_single;
1233         ref.dev          = dev;
1234         ref.dev_addr     = dma_handle;
1235         ref.size         = size;
1236         ref.direction    = direction;
1237         ref.sg_call_ents = 0;
1238
1239         check_sync(dev, &ref, false);
1240 }
1241 EXPORT_SYMBOL(debug_dma_sync_single_for_device);
1242
1243 void debug_dma_sync_single_range_for_cpu(struct device *dev,
1244                                          dma_addr_t dma_handle,
1245                                          unsigned long offset, size_t size,
1246                                          int direction)
1247 {
1248         struct dma_debug_entry ref;
1249
1250         if (unlikely(global_disable))
1251                 return;
1252
1253         ref.type         = dma_debug_single;
1254         ref.dev          = dev;
1255         ref.dev_addr     = dma_handle;
1256         ref.size         = offset + size;
1257         ref.direction    = direction;
1258         ref.sg_call_ents = 0;
1259
1260         check_sync(dev, &ref, true);
1261 }
1262 EXPORT_SYMBOL(debug_dma_sync_single_range_for_cpu);
1263
1264 void debug_dma_sync_single_range_for_device(struct device *dev,
1265                                             dma_addr_t dma_handle,
1266                                             unsigned long offset,
1267                                             size_t size, int direction)
1268 {
1269         struct dma_debug_entry ref;
1270
1271         if (unlikely(global_disable))
1272                 return;
1273
1274         ref.type         = dma_debug_single;
1275         ref.dev          = dev;
1276         ref.dev_addr     = dma_handle;
1277         ref.size         = offset + size;
1278         ref.direction    = direction;
1279         ref.sg_call_ents = 0;
1280
1281         check_sync(dev, &ref, false);
1282 }
1283 EXPORT_SYMBOL(debug_dma_sync_single_range_for_device);
1284
1285 void debug_dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
1286                                int nelems, int direction)
1287 {
1288         struct scatterlist *s;
1289         int mapped_ents = 0, i;
1290
1291         if (unlikely(global_disable))
1292                 return;
1293
1294         for_each_sg(sg, s, nelems, i) {
1295
1296                 struct dma_debug_entry ref = {
1297                         .type           = dma_debug_sg,
1298                         .dev            = dev,
1299                         .paddr          = sg_phys(s),
1300                         .dev_addr       = sg_dma_address(s),
1301                         .size           = sg_dma_len(s),
1302                         .direction      = direction,
1303                         .sg_call_ents   = nelems,
1304                 };
1305
1306                 if (!i)
1307                         mapped_ents = get_nr_mapped_entries(dev, &ref);
1308
1309                 if (i >= mapped_ents)
1310                         break;
1311
1312                 check_sync(dev, &ref, true);
1313         }
1314 }
1315 EXPORT_SYMBOL(debug_dma_sync_sg_for_cpu);
1316
1317 void debug_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
1318                                   int nelems, int direction)
1319 {
1320         struct scatterlist *s;
1321         int mapped_ents = 0, i;
1322
1323         if (unlikely(global_disable))
1324                 return;
1325
1326         for_each_sg(sg, s, nelems, i) {
1327
1328                 struct dma_debug_entry ref = {
1329                         .type           = dma_debug_sg,
1330                         .dev            = dev,
1331                         .paddr          = sg_phys(s),
1332                         .dev_addr       = sg_dma_address(s),
1333                         .size           = sg_dma_len(s),
1334                         .direction      = direction,
1335                         .sg_call_ents   = nelems,
1336                 };
1337                 if (!i)
1338                         mapped_ents = get_nr_mapped_entries(dev, &ref);
1339
1340                 if (i >= mapped_ents)
1341                         break;
1342
1343                 check_sync(dev, &ref, false);
1344         }
1345 }
1346 EXPORT_SYMBOL(debug_dma_sync_sg_for_device);
1347
1348 static int __init dma_debug_driver_setup(char *str)
1349 {
1350         int i;
1351
1352         for (i = 0; i < NAME_MAX_LEN - 1; ++i, ++str) {
1353                 current_driver_name[i] = *str;
1354                 if (*str == 0)
1355                         break;
1356         }
1357
1358         if (current_driver_name[0])
1359                 pr_info("DMA-API: enable driver filter for driver [%s]\n",
1360                         current_driver_name);
1361
1362
1363         return 1;
1364 }
1365 __setup("dma_debug_driver=", dma_debug_driver_setup);