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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
41enum {
42 dma_debug_single,
43 dma_debug_page,
44 dma_debug_sg,
45 dma_debug_coherent,
46};
47
48enum 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/**
57 * struct dma_debug_entry - track a dma_map* or dma_alloc_coherent mapping
58 * @list: node on pre-allocated free_entries list
59 * @dev: 'dev' argument to dma_map_{page|single|sg} or dma_alloc_coherent
60 * @type: single, page, sg, coherent
61 * @pfn: page frame of the start address
62 * @offset: offset of mapping relative to pfn
63 * @size: length of the mapping
64 * @direction: enum dma_data_direction
65 * @sg_call_ents: 'nents' from dma_map_sg
66 * @sg_mapped_ents: 'mapped_ents' from dma_map_sg
67 * @map_err_type: track whether dma_mapping_error() was checked
68 * @stacktrace: support backtraces when a violation is detected
69 */
70struct dma_debug_entry {
71 struct list_head list;
72 struct device *dev;
73 int type;
74 unsigned long pfn;
75 size_t offset;
76 u64 dev_addr;
77 u64 size;
78 int direction;
79 int sg_call_ents;
80 int sg_mapped_ents;
81 enum map_err_types map_err_type;
82#ifdef CONFIG_STACKTRACE
83 struct stack_trace stacktrace;
84 unsigned long st_entries[DMA_DEBUG_STACKTRACE_ENTRIES];
85#endif
86};
87
88typedef bool (*match_fn)(struct dma_debug_entry *, struct dma_debug_entry *);
89
90struct hash_bucket {
91 struct list_head list;
92 spinlock_t lock;
93} ____cacheline_aligned_in_smp;
94
95/* Hash list to save the allocated dma addresses */
96static struct hash_bucket dma_entry_hash[HASH_SIZE];
97/* List of pre-allocated dma_debug_entry's */
98static LIST_HEAD(free_entries);
99/* Lock for the list above */
100static DEFINE_SPINLOCK(free_entries_lock);
101
102/* Global disable flag - will be set in case of an error */
103static u32 global_disable __read_mostly;
104
105/* Global error count */
106static u32 error_count;
107
108/* Global error show enable*/
109static u32 show_all_errors __read_mostly;
110/* Number of errors to show */
111static u32 show_num_errors = 1;
112
113static u32 num_free_entries;
114static u32 min_free_entries;
115static u32 nr_total_entries;
116
117/* number of preallocated entries requested by kernel cmdline */
118static u32 req_entries;
119
120/* debugfs dentry's for the stuff above */
121static struct dentry *dma_debug_dent __read_mostly;
122static struct dentry *global_disable_dent __read_mostly;
123static struct dentry *error_count_dent __read_mostly;
124static struct dentry *show_all_errors_dent __read_mostly;
125static struct dentry *show_num_errors_dent __read_mostly;
126static struct dentry *num_free_entries_dent __read_mostly;
127static struct dentry *min_free_entries_dent __read_mostly;
128static struct dentry *filter_dent __read_mostly;
129
130/* per-driver filter related state */
131
132#define NAME_MAX_LEN 64
133
134static char current_driver_name[NAME_MAX_LEN] __read_mostly;
135static struct device_driver *current_driver __read_mostly;
136
137static DEFINE_RWLOCK(driver_name_lock);
138
139static const char *const maperr2str[] = {
140 [MAP_ERR_CHECK_NOT_APPLICABLE] = "dma map error check not applicable",
141 [MAP_ERR_NOT_CHECKED] = "dma map error not checked",
142 [MAP_ERR_CHECKED] = "dma map error checked",
143};
144
145static const char *type2name[4] = { "single", "page",
146 "scather-gather", "coherent" };
147
148static const char *dir2name[4] = { "DMA_BIDIRECTIONAL", "DMA_TO_DEVICE",
149 "DMA_FROM_DEVICE", "DMA_NONE" };
150
151/*
152 * The access to some variables in this macro is racy. We can't use atomic_t
153 * here because all these variables are exported to debugfs. Some of them even
154 * writeable. This is also the reason why a lock won't help much. But anyway,
155 * the races are no big deal. Here is why:
156 *
157 * error_count: the addition is racy, but the worst thing that can happen is
158 * that we don't count some errors
159 * show_num_errors: the subtraction is racy. Also no big deal because in
160 * worst case this will result in one warning more in the
161 * system log than the user configured. This variable is
162 * writeable via debugfs.
163 */
164static inline void dump_entry_trace(struct dma_debug_entry *entry)
165{
166#ifdef CONFIG_STACKTRACE
167 if (entry) {
168 pr_warning("Mapped at:\n");
169 print_stack_trace(&entry->stacktrace, 0);
170 }
171#endif
172}
173
174static bool driver_filter(struct device *dev)
175{
176 struct device_driver *drv;
177 unsigned long flags;
178 bool ret;
179
180 /* driver filter off */
181 if (likely(!current_driver_name[0]))
182 return true;
183
184 /* driver filter on and initialized */
185 if (current_driver && dev && dev->driver == current_driver)
186 return true;
187
188 /* driver filter on, but we can't filter on a NULL device... */
189 if (!dev)
190 return false;
191
192 if (current_driver || !current_driver_name[0])
193 return false;
194
195 /* driver filter on but not yet initialized */
196 drv = dev->driver;
197 if (!drv)
198 return false;
199
200 /* lock to protect against change of current_driver_name */
201 read_lock_irqsave(&driver_name_lock, flags);
202
203 ret = false;
204 if (drv->name &&
205 strncmp(current_driver_name, drv->name, NAME_MAX_LEN - 1) == 0) {
206 current_driver = drv;
207 ret = true;
208 }
209
210 read_unlock_irqrestore(&driver_name_lock, flags);
211
212 return ret;
213}
214
215#define err_printk(dev, entry, format, arg...) do { \
216 error_count += 1; \
217 if (driver_filter(dev) && \
218 (show_all_errors || show_num_errors > 0)) { \
219 WARN(1, "%s %s: " format, \
220 dev ? dev_driver_string(dev) : "NULL", \
221 dev ? dev_name(dev) : "NULL", ## arg); \
222 dump_entry_trace(entry); \
223 } \
224 if (!show_all_errors && show_num_errors > 0) \
225 show_num_errors -= 1; \
226 } while (0);
227
228/*
229 * Hash related functions
230 *
231 * Every DMA-API request is saved into a struct dma_debug_entry. To
232 * have quick access to these structs they are stored into a hash.
233 */
234static int hash_fn(struct dma_debug_entry *entry)
235{
236 /*
237 * Hash function is based on the dma address.
238 * We use bits 20-27 here as the index into the hash
239 */
240 return (entry->dev_addr >> HASH_FN_SHIFT) & HASH_FN_MASK;
241}
242
243/*
244 * Request exclusive access to a hash bucket for a given dma_debug_entry.
245 */
246static struct hash_bucket *get_hash_bucket(struct dma_debug_entry *entry,
247 unsigned long *flags)
248{
249 int idx = hash_fn(entry);
250 unsigned long __flags;
251
252 spin_lock_irqsave(&dma_entry_hash[idx].lock, __flags);
253 *flags = __flags;
254 return &dma_entry_hash[idx];
255}
256
257/*
258 * Give up exclusive access to the hash bucket
259 */
260static void put_hash_bucket(struct hash_bucket *bucket,
261 unsigned long *flags)
262{
263 unsigned long __flags = *flags;
264
265 spin_unlock_irqrestore(&bucket->lock, __flags);
266}
267
268static bool exact_match(struct dma_debug_entry *a, struct dma_debug_entry *b)
269{
270 return ((a->dev_addr == b->dev_addr) &&
271 (a->dev == b->dev)) ? true : false;
272}
273
274static bool containing_match(struct dma_debug_entry *a,
275 struct dma_debug_entry *b)
276{
277 if (a->dev != b->dev)
278 return false;
279
280 if ((b->dev_addr <= a->dev_addr) &&
281 ((b->dev_addr + b->size) >= (a->dev_addr + a->size)))
282 return true;
283
284 return false;
285}
286
287/*
288 * Search a given entry in the hash bucket list
289 */
290static struct dma_debug_entry *__hash_bucket_find(struct hash_bucket *bucket,
291 struct dma_debug_entry *ref,
292 match_fn match)
293{
294 struct dma_debug_entry *entry, *ret = NULL;
295 int matches = 0, match_lvl, last_lvl = -1;
296
297 list_for_each_entry(entry, &bucket->list, list) {
298 if (!match(ref, entry))
299 continue;
300
301 /*
302 * Some drivers map the same physical address multiple
303 * times. Without a hardware IOMMU this results in the
304 * same device addresses being put into the dma-debug
305 * hash multiple times too. This can result in false
306 * positives being reported. Therefore we implement a
307 * best-fit algorithm here which returns the entry from
308 * the hash which fits best to the reference value
309 * instead of the first-fit.
310 */
311 matches += 1;
312 match_lvl = 0;
313 entry->size == ref->size ? ++match_lvl : 0;
314 entry->type == ref->type ? ++match_lvl : 0;
315 entry->direction == ref->direction ? ++match_lvl : 0;
316 entry->sg_call_ents == ref->sg_call_ents ? ++match_lvl : 0;
317
318 if (match_lvl == 4) {
319 /* perfect-fit - return the result */
320 return entry;
321 } else if (match_lvl > last_lvl) {
322 /*
323 * We found an entry that fits better then the
324 * previous one or it is the 1st match.
325 */
326 last_lvl = match_lvl;
327 ret = entry;
328 }
329 }
330
331 /*
332 * If we have multiple matches but no perfect-fit, just return
333 * NULL.
334 */
335 ret = (matches == 1) ? ret : NULL;
336
337 return ret;
338}
339
340static struct dma_debug_entry *bucket_find_exact(struct hash_bucket *bucket,
341 struct dma_debug_entry *ref)
342{
343 return __hash_bucket_find(bucket, ref, exact_match);
344}
345
346static struct dma_debug_entry *bucket_find_contain(struct hash_bucket **bucket,
347 struct dma_debug_entry *ref,
348 unsigned long *flags)
349{
350
351 unsigned int max_range = dma_get_max_seg_size(ref->dev);
352 struct dma_debug_entry *entry, index = *ref;
353 unsigned int range = 0;
354
355 while (range <= max_range) {
356 entry = __hash_bucket_find(*bucket, &index, containing_match);
357
358 if (entry)
359 return entry;
360
361 /*
362 * Nothing found, go back a hash bucket
363 */
364 put_hash_bucket(*bucket, flags);
365 range += (1 << HASH_FN_SHIFT);
366 index.dev_addr -= (1 << HASH_FN_SHIFT);
367 *bucket = get_hash_bucket(&index, flags);
368 }
369
370 return NULL;
371}
372
373/*
374 * Add an entry to a hash bucket
375 */
376static void hash_bucket_add(struct hash_bucket *bucket,
377 struct dma_debug_entry *entry)
378{
379 list_add_tail(&entry->list, &bucket->list);
380}
381
382/*
383 * Remove entry from a hash bucket list
384 */
385static void hash_bucket_del(struct dma_debug_entry *entry)
386{
387 list_del(&entry->list);
388}
389
390static unsigned long long phys_addr(struct dma_debug_entry *entry)
391{
392 return page_to_phys(pfn_to_page(entry->pfn)) + entry->offset;
393}
394
395/*
396 * Dump mapping entries for debugging purposes
397 */
398void debug_dma_dump_mappings(struct device *dev)
399{
400 int idx;
401
402 for (idx = 0; idx < HASH_SIZE; idx++) {
403 struct hash_bucket *bucket = &dma_entry_hash[idx];
404 struct dma_debug_entry *entry;
405 unsigned long flags;
406
407 spin_lock_irqsave(&bucket->lock, flags);
408
409 list_for_each_entry(entry, &bucket->list, list) {
410 if (!dev || dev == entry->dev) {
411 dev_info(entry->dev,
412 "%s idx %d P=%Lx N=%lx D=%Lx L=%Lx %s %s\n",
413 type2name[entry->type], idx,
414 phys_addr(entry), entry->pfn,
415 entry->dev_addr, entry->size,
416 dir2name[entry->direction],
417 maperr2str[entry->map_err_type]);
418 }
419 }
420
421 spin_unlock_irqrestore(&bucket->lock, flags);
422 }
423}
424EXPORT_SYMBOL(debug_dma_dump_mappings);
425
426/*
427 * For each mapping (initial cacheline in the case of
428 * dma_alloc_coherent/dma_map_page, initial cacheline in each page of a
429 * scatterlist, or the cacheline specified in dma_map_single) insert
430 * into this tree using the cacheline as the key. At
431 * dma_unmap_{single|sg|page} or dma_free_coherent delete the entry. If
432 * the entry already exists at insertion time add a tag as a reference
433 * count for the overlapping mappings. For now, the overlap tracking
434 * just ensures that 'unmaps' balance 'maps' before marking the
435 * cacheline idle, but we should also be flagging overlaps as an API
436 * violation.
437 *
438 * Memory usage is mostly constrained by the maximum number of available
439 * dma-debug entries in that we need a free dma_debug_entry before
440 * inserting into the tree. In the case of dma_map_page and
441 * dma_alloc_coherent there is only one dma_debug_entry and one
442 * dma_active_cacheline entry to track per event. dma_map_sg(), on the
443 * other hand, consumes a single dma_debug_entry, but inserts 'nents'
444 * entries into the tree.
445 *
446 * At any time debug_dma_assert_idle() can be called to trigger a
447 * warning if any cachelines in the given page are in the active set.
448 */
449static RADIX_TREE(dma_active_cacheline, GFP_NOWAIT);
450static DEFINE_SPINLOCK(radix_lock);
451#define ACTIVE_CACHELINE_MAX_OVERLAP ((1 << RADIX_TREE_MAX_TAGS) - 1)
452#define CACHELINE_PER_PAGE_SHIFT (PAGE_SHIFT - L1_CACHE_SHIFT)
453#define CACHELINES_PER_PAGE (1 << CACHELINE_PER_PAGE_SHIFT)
454
455static phys_addr_t to_cacheline_number(struct dma_debug_entry *entry)
456{
457 return (entry->pfn << CACHELINE_PER_PAGE_SHIFT) +
458 (entry->offset >> L1_CACHE_SHIFT);
459}
460
461static int active_cacheline_read_overlap(phys_addr_t cln)
462{
463 int overlap = 0, i;
464
465 for (i = RADIX_TREE_MAX_TAGS - 1; i >= 0; i--)
466 if (radix_tree_tag_get(&dma_active_cacheline, cln, i))
467 overlap |= 1 << i;
468 return overlap;
469}
470
471static int active_cacheline_set_overlap(phys_addr_t cln, int overlap)
472{
473 int i;
474
475 if (overlap > ACTIVE_CACHELINE_MAX_OVERLAP || overlap < 0)
476 return overlap;
477
478 for (i = RADIX_TREE_MAX_TAGS - 1; i >= 0; i--)
479 if (overlap & 1 << i)
480 radix_tree_tag_set(&dma_active_cacheline, cln, i);
481 else
482 radix_tree_tag_clear(&dma_active_cacheline, cln, i);
483
484 return overlap;
485}
486
487static void active_cacheline_inc_overlap(phys_addr_t cln)
488{
489 int overlap = active_cacheline_read_overlap(cln);
490
491 overlap = active_cacheline_set_overlap(cln, ++overlap);
492
493 /* If we overflowed the overlap counter then we're potentially
494 * leaking dma-mappings. Otherwise, if maps and unmaps are
495 * balanced then this overflow may cause false negatives in
496 * debug_dma_assert_idle() as the cacheline may be marked idle
497 * prematurely.
498 */
499 WARN_ONCE(overlap > ACTIVE_CACHELINE_MAX_OVERLAP,
500 "DMA-API: exceeded %d overlapping mappings of cacheline %pa\n",
501 ACTIVE_CACHELINE_MAX_OVERLAP, &cln);
502}
503
504static int active_cacheline_dec_overlap(phys_addr_t cln)
505{
506 int overlap = active_cacheline_read_overlap(cln);
507
508 return active_cacheline_set_overlap(cln, --overlap);
509}
510
511static int active_cacheline_insert(struct dma_debug_entry *entry)
512{
513 phys_addr_t cln = to_cacheline_number(entry);
514 unsigned long flags;
515 int rc;
516
517 /* If the device is not writing memory then we don't have any
518 * concerns about the cpu consuming stale data. This mitigates
519 * legitimate usages of overlapping mappings.
520 */
521 if (entry->direction == DMA_TO_DEVICE)
522 return 0;
523
524 spin_lock_irqsave(&radix_lock, flags);
525 rc = radix_tree_insert(&dma_active_cacheline, cln, entry);
526 if (rc == -EEXIST)
527 active_cacheline_inc_overlap(cln);
528 spin_unlock_irqrestore(&radix_lock, flags);
529
530 return rc;
531}
532
533static void active_cacheline_remove(struct dma_debug_entry *entry)
534{
535 phys_addr_t cln = to_cacheline_number(entry);
536 unsigned long flags;
537
538 /* ...mirror the insert case */
539 if (entry->direction == DMA_TO_DEVICE)
540 return;
541
542 spin_lock_irqsave(&radix_lock, flags);
543 /* since we are counting overlaps the final put of the
544 * cacheline will occur when the overlap count is 0.
545 * active_cacheline_dec_overlap() returns -1 in that case
546 */
547 if (active_cacheline_dec_overlap(cln) < 0)
548 radix_tree_delete(&dma_active_cacheline, cln);
549 spin_unlock_irqrestore(&radix_lock, flags);
550}
551
552/**
553 * debug_dma_assert_idle() - assert that a page is not undergoing dma
554 * @page: page to lookup in the dma_active_cacheline tree
555 *
556 * Place a call to this routine in cases where the cpu touching the page
557 * before the dma completes (page is dma_unmapped) will lead to data
558 * corruption.
559 */
560void debug_dma_assert_idle(struct page *page)
561{
562 static struct dma_debug_entry *ents[CACHELINES_PER_PAGE];
563 struct dma_debug_entry *entry = NULL;
564 void **results = (void **) &ents;
565 unsigned int nents, i;
566 unsigned long flags;
567 phys_addr_t cln;
568
569 if (!page)
570 return;
571
572 cln = (phys_addr_t) page_to_pfn(page) << CACHELINE_PER_PAGE_SHIFT;
573 spin_lock_irqsave(&radix_lock, flags);
574 nents = radix_tree_gang_lookup(&dma_active_cacheline, results, cln,
575 CACHELINES_PER_PAGE);
576 for (i = 0; i < nents; i++) {
577 phys_addr_t ent_cln = to_cacheline_number(ents[i]);
578
579 if (ent_cln == cln) {
580 entry = ents[i];
581 break;
582 } else if (ent_cln >= cln + CACHELINES_PER_PAGE)
583 break;
584 }
585 spin_unlock_irqrestore(&radix_lock, flags);
586
587 if (!entry)
588 return;
589
590 cln = to_cacheline_number(entry);
591 err_printk(entry->dev, entry,
592 "DMA-API: cpu touching an active dma mapped cacheline [cln=%pa]\n",
593 &cln);
594}
595
596/*
597 * Wrapper function for adding an entry to the hash.
598 * This function takes care of locking itself.
599 */
600static void add_dma_entry(struct dma_debug_entry *entry)
601{
602 struct hash_bucket *bucket;
603 unsigned long flags;
604 int rc;
605
606 bucket = get_hash_bucket(entry, &flags);
607 hash_bucket_add(bucket, entry);
608 put_hash_bucket(bucket, &flags);
609
610 rc = active_cacheline_insert(entry);
611 if (rc == -ENOMEM) {
612 pr_err("DMA-API: cacheline tracking ENOMEM, dma-debug disabled\n");
613 global_disable = true;
614 }
615
616 /* TODO: report -EEXIST errors here as overlapping mappings are
617 * not supported by the DMA API
618 */
619}
620
621static struct dma_debug_entry *__dma_entry_alloc(void)
622{
623 struct dma_debug_entry *entry;
624
625 entry = list_entry(free_entries.next, struct dma_debug_entry, list);
626 list_del(&entry->list);
627 memset(entry, 0, sizeof(*entry));
628
629 num_free_entries -= 1;
630 if (num_free_entries < min_free_entries)
631 min_free_entries = num_free_entries;
632
633 return entry;
634}
635
636/* struct dma_entry allocator
637 *
638 * The next two functions implement the allocator for
639 * struct dma_debug_entries.
640 */
641static struct dma_debug_entry *dma_entry_alloc(void)
642{
643 struct dma_debug_entry *entry;
644 unsigned long flags;
645
646 spin_lock_irqsave(&free_entries_lock, flags);
647
648 if (list_empty(&free_entries)) {
649 pr_err("DMA-API: debugging out of memory - disabling\n");
650 global_disable = true;
651 spin_unlock_irqrestore(&free_entries_lock, flags);
652 return NULL;
653 }
654
655 entry = __dma_entry_alloc();
656
657 spin_unlock_irqrestore(&free_entries_lock, flags);
658
659#ifdef CONFIG_STACKTRACE
660 entry->stacktrace.max_entries = DMA_DEBUG_STACKTRACE_ENTRIES;
661 entry->stacktrace.entries = entry->st_entries;
662 entry->stacktrace.skip = 2;
663 save_stack_trace(&entry->stacktrace);
664#endif
665
666 return entry;
667}
668
669static void dma_entry_free(struct dma_debug_entry *entry)
670{
671 unsigned long flags;
672
673 active_cacheline_remove(entry);
674
675 /*
676 * add to beginning of the list - this way the entries are
677 * more likely cache hot when they are reallocated.
678 */
679 spin_lock_irqsave(&free_entries_lock, flags);
680 list_add(&entry->list, &free_entries);
681 num_free_entries += 1;
682 spin_unlock_irqrestore(&free_entries_lock, flags);
683}
684
685int dma_debug_resize_entries(u32 num_entries)
686{
687 int i, delta, ret = 0;
688 unsigned long flags;
689 struct dma_debug_entry *entry;
690 LIST_HEAD(tmp);
691
692 spin_lock_irqsave(&free_entries_lock, flags);
693
694 if (nr_total_entries < num_entries) {
695 delta = num_entries - nr_total_entries;
696
697 spin_unlock_irqrestore(&free_entries_lock, flags);
698
699 for (i = 0; i < delta; i++) {
700 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
701 if (!entry)
702 break;
703
704 list_add_tail(&entry->list, &tmp);
705 }
706
707 spin_lock_irqsave(&free_entries_lock, flags);
708
709 list_splice(&tmp, &free_entries);
710 nr_total_entries += i;
711 num_free_entries += i;
712 } else {
713 delta = nr_total_entries - num_entries;
714
715 for (i = 0; i < delta && !list_empty(&free_entries); i++) {
716 entry = __dma_entry_alloc();
717 kfree(entry);
718 }
719
720 nr_total_entries -= i;
721 }
722
723 if (nr_total_entries != num_entries)
724 ret = 1;
725
726 spin_unlock_irqrestore(&free_entries_lock, flags);
727
728 return ret;
729}
730EXPORT_SYMBOL(dma_debug_resize_entries);
731
732/*
733 * DMA-API debugging init code
734 *
735 * The init code does two things:
736 * 1. Initialize core data structures
737 * 2. Preallocate a given number of dma_debug_entry structs
738 */
739
740static int prealloc_memory(u32 num_entries)
741{
742 struct dma_debug_entry *entry, *next_entry;
743 int i;
744
745 for (i = 0; i < num_entries; ++i) {
746 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
747 if (!entry)
748 goto out_err;
749
750 list_add_tail(&entry->list, &free_entries);
751 }
752
753 num_free_entries = num_entries;
754 min_free_entries = num_entries;
755
756 pr_info("DMA-API: preallocated %d debug entries\n", num_entries);
757
758 return 0;
759
760out_err:
761
762 list_for_each_entry_safe(entry, next_entry, &free_entries, list) {
763 list_del(&entry->list);
764 kfree(entry);
765 }
766
767 return -ENOMEM;
768}
769
770static ssize_t filter_read(struct file *file, char __user *user_buf,
771 size_t count, loff_t *ppos)
772{
773 char buf[NAME_MAX_LEN + 1];
774 unsigned long flags;
775 int len;
776
777 if (!current_driver_name[0])
778 return 0;
779
780 /*
781 * We can't copy to userspace directly because current_driver_name can
782 * only be read under the driver_name_lock with irqs disabled. So
783 * create a temporary copy first.
784 */
785 read_lock_irqsave(&driver_name_lock, flags);
786 len = scnprintf(buf, NAME_MAX_LEN + 1, "%s\n", current_driver_name);
787 read_unlock_irqrestore(&driver_name_lock, flags);
788
789 return simple_read_from_buffer(user_buf, count, ppos, buf, len);
790}
791
792static ssize_t filter_write(struct file *file, const char __user *userbuf,
793 size_t count, loff_t *ppos)
794{
795 char buf[NAME_MAX_LEN];
796 unsigned long flags;
797 size_t len;
798 int i;
799
800 /*
801 * We can't copy from userspace directly. Access to
802 * current_driver_name is protected with a write_lock with irqs
803 * disabled. Since copy_from_user can fault and may sleep we
804 * need to copy to temporary buffer first
805 */
806 len = min(count, (size_t)(NAME_MAX_LEN - 1));
807 if (copy_from_user(buf, userbuf, len))
808 return -EFAULT;
809
810 buf[len] = 0;
811
812 write_lock_irqsave(&driver_name_lock, flags);
813
814 /*
815 * Now handle the string we got from userspace very carefully.
816 * The rules are:
817 * - only use the first token we got
818 * - token delimiter is everything looking like a space
819 * character (' ', '\n', '\t' ...)
820 *
821 */
822 if (!isalnum(buf[0])) {
823 /*
824 * If the first character userspace gave us is not
825 * alphanumerical then assume the filter should be
826 * switched off.
827 */
828 if (current_driver_name[0])
829 pr_info("DMA-API: switching off dma-debug driver filter\n");
830 current_driver_name[0] = 0;
831 current_driver = NULL;
832 goto out_unlock;
833 }
834
835 /*
836 * Now parse out the first token and use it as the name for the
837 * driver to filter for.
838 */
839 for (i = 0; i < NAME_MAX_LEN - 1; ++i) {
840 current_driver_name[i] = buf[i];
841 if (isspace(buf[i]) || buf[i] == ' ' || buf[i] == 0)
842 break;
843 }
844 current_driver_name[i] = 0;
845 current_driver = NULL;
846
847 pr_info("DMA-API: enable driver filter for driver [%s]\n",
848 current_driver_name);
849
850out_unlock:
851 write_unlock_irqrestore(&driver_name_lock, flags);
852
853 return count;
854}
855
856static const struct file_operations filter_fops = {
857 .read = filter_read,
858 .write = filter_write,
859 .llseek = default_llseek,
860};
861
862static int dma_debug_fs_init(void)
863{
864 dma_debug_dent = debugfs_create_dir("dma-api", NULL);
865 if (!dma_debug_dent) {
866 pr_err("DMA-API: can not create debugfs directory\n");
867 return -ENOMEM;
868 }
869
870 global_disable_dent = debugfs_create_bool("disabled", 0444,
871 dma_debug_dent,
872 &global_disable);
873 if (!global_disable_dent)
874 goto out_err;
875
876 error_count_dent = debugfs_create_u32("error_count", 0444,
877 dma_debug_dent, &error_count);
878 if (!error_count_dent)
879 goto out_err;
880
881 show_all_errors_dent = debugfs_create_u32("all_errors", 0644,
882 dma_debug_dent,
883 &show_all_errors);
884 if (!show_all_errors_dent)
885 goto out_err;
886
887 show_num_errors_dent = debugfs_create_u32("num_errors", 0644,
888 dma_debug_dent,
889 &show_num_errors);
890 if (!show_num_errors_dent)
891 goto out_err;
892
893 num_free_entries_dent = debugfs_create_u32("num_free_entries", 0444,
894 dma_debug_dent,
895 &num_free_entries);
896 if (!num_free_entries_dent)
897 goto out_err;
898
899 min_free_entries_dent = debugfs_create_u32("min_free_entries", 0444,
900 dma_debug_dent,
901 &min_free_entries);
902 if (!min_free_entries_dent)
903 goto out_err;
904
905 filter_dent = debugfs_create_file("driver_filter", 0644,
906 dma_debug_dent, NULL, &filter_fops);
907 if (!filter_dent)
908 goto out_err;
909
910 return 0;
911
912out_err:
913 debugfs_remove_recursive(dma_debug_dent);
914
915 return -ENOMEM;
916}
917
918static int device_dma_allocations(struct device *dev, struct dma_debug_entry **out_entry)
919{
920 struct dma_debug_entry *entry;
921 unsigned long flags;
922 int count = 0, i;
923
924 local_irq_save(flags);
925
926 for (i = 0; i < HASH_SIZE; ++i) {
927 spin_lock(&dma_entry_hash[i].lock);
928 list_for_each_entry(entry, &dma_entry_hash[i].list, list) {
929 if (entry->dev == dev) {
930 count += 1;
931 *out_entry = entry;
932 }
933 }
934 spin_unlock(&dma_entry_hash[i].lock);
935 }
936
937 local_irq_restore(flags);
938
939 return count;
940}
941
942static int dma_debug_device_change(struct notifier_block *nb, unsigned long action, void *data)
943{
944 struct device *dev = data;
945 struct dma_debug_entry *uninitialized_var(entry);
946 int count;
947
948 if (global_disable)
949 return 0;
950
951 switch (action) {
952 case BUS_NOTIFY_UNBOUND_DRIVER:
953 count = device_dma_allocations(dev, &entry);
954 if (count == 0)
955 break;
956 err_printk(dev, entry, "DMA-API: device driver has pending "
957 "DMA allocations while released from device "
958 "[count=%d]\n"
959 "One of leaked entries details: "
960 "[device address=0x%016llx] [size=%llu bytes] "
961 "[mapped with %s] [mapped as %s]\n",
962 count, entry->dev_addr, entry->size,
963 dir2name[entry->direction], type2name[entry->type]);
964 break;
965 default:
966 break;
967 }
968
969 return 0;
970}
971
972void dma_debug_add_bus(struct bus_type *bus)
973{
974 struct notifier_block *nb;
975
976 if (global_disable)
977 return;
978
979 nb = kzalloc(sizeof(struct notifier_block), GFP_KERNEL);
980 if (nb == NULL) {
981 pr_err("dma_debug_add_bus: out of memory\n");
982 return;
983 }
984
985 nb->notifier_call = dma_debug_device_change;
986
987 bus_register_notifier(bus, nb);
988}
989
990/*
991 * Let the architectures decide how many entries should be preallocated.
992 */
993void dma_debug_init(u32 num_entries)
994{
995 int i;
996
997 if (global_disable)
998 return;
999
1000 for (i = 0; i < HASH_SIZE; ++i) {
1001 INIT_LIST_HEAD(&dma_entry_hash[i].list);
1002 spin_lock_init(&dma_entry_hash[i].lock);
1003 }
1004
1005 if (dma_debug_fs_init() != 0) {
1006 pr_err("DMA-API: error creating debugfs entries - disabling\n");
1007 global_disable = true;
1008
1009 return;
1010 }
1011
1012 if (req_entries)
1013 num_entries = req_entries;
1014
1015 if (prealloc_memory(num_entries) != 0) {
1016 pr_err("DMA-API: debugging out of memory error - disabled\n");
1017 global_disable = true;
1018
1019 return;
1020 }
1021
1022 nr_total_entries = num_free_entries;
1023
1024 pr_info("DMA-API: debugging enabled by kernel config\n");
1025}
1026
1027static __init int dma_debug_cmdline(char *str)
1028{
1029 if (!str)
1030 return -EINVAL;
1031
1032 if (strncmp(str, "off", 3) == 0) {
1033 pr_info("DMA-API: debugging disabled on kernel command line\n");
1034 global_disable = true;
1035 }
1036
1037 return 0;
1038}
1039
1040static __init int dma_debug_entries_cmdline(char *str)
1041{
1042 int res;
1043
1044 if (!str)
1045 return -EINVAL;
1046
1047 res = get_option(&str, &req_entries);
1048
1049 if (!res)
1050 req_entries = 0;
1051
1052 return 0;
1053}
1054
1055__setup("dma_debug=", dma_debug_cmdline);
1056__setup("dma_debug_entries=", dma_debug_entries_cmdline);
1057
1058static void check_unmap(struct dma_debug_entry *ref)
1059{
1060 struct dma_debug_entry *entry;
1061 struct hash_bucket *bucket;
1062 unsigned long flags;
1063
1064 bucket = get_hash_bucket(ref, &flags);
1065 entry = bucket_find_exact(bucket, ref);
1066
1067 if (!entry) {
1068 /* must drop lock before calling dma_mapping_error */
1069 put_hash_bucket(bucket, &flags);
1070
1071 if (dma_mapping_error(ref->dev, ref->dev_addr)) {
1072 err_printk(ref->dev, NULL,
1073 "DMA-API: device driver tries to free an "
1074 "invalid DMA memory address\n");
1075 } else {
1076 err_printk(ref->dev, NULL,
1077 "DMA-API: device driver tries to free DMA "
1078 "memory it has not allocated [device "
1079 "address=0x%016llx] [size=%llu bytes]\n",
1080 ref->dev_addr, ref->size);
1081 }
1082 return;
1083 }
1084
1085 if (ref->size != entry->size) {
1086 err_printk(ref->dev, entry, "DMA-API: device driver frees "
1087 "DMA memory with different size "
1088 "[device address=0x%016llx] [map size=%llu bytes] "
1089 "[unmap size=%llu bytes]\n",
1090 ref->dev_addr, entry->size, ref->size);
1091 }
1092
1093 if (ref->type != entry->type) {
1094 err_printk(ref->dev, entry, "DMA-API: device driver frees "
1095 "DMA memory with wrong function "
1096 "[device address=0x%016llx] [size=%llu bytes] "
1097 "[mapped as %s] [unmapped as %s]\n",
1098 ref->dev_addr, ref->size,
1099 type2name[entry->type], type2name[ref->type]);
1100 } else if ((entry->type == dma_debug_coherent) &&
1101 (phys_addr(ref) != phys_addr(entry))) {
1102 err_printk(ref->dev, entry, "DMA-API: device driver frees "
1103 "DMA memory with different CPU address "
1104 "[device address=0x%016llx] [size=%llu bytes] "
1105 "[cpu alloc address=0x%016llx] "
1106 "[cpu free address=0x%016llx]",
1107 ref->dev_addr, ref->size,
1108 phys_addr(entry),
1109 phys_addr(ref));
1110 }
1111
1112 if (ref->sg_call_ents && ref->type == dma_debug_sg &&
1113 ref->sg_call_ents != entry->sg_call_ents) {
1114 err_printk(ref->dev, entry, "DMA-API: device driver frees "
1115 "DMA sg list with different entry count "
1116 "[map count=%d] [unmap count=%d]\n",
1117 entry->sg_call_ents, ref->sg_call_ents);
1118 }
1119
1120 /*
1121 * This may be no bug in reality - but most implementations of the
1122 * DMA API don't handle this properly, so check for it here
1123 */
1124 if (ref->direction != entry->direction) {
1125 err_printk(ref->dev, entry, "DMA-API: device driver frees "
1126 "DMA memory with different direction "
1127 "[device address=0x%016llx] [size=%llu bytes] "
1128 "[mapped with %s] [unmapped with %s]\n",
1129 ref->dev_addr, ref->size,
1130 dir2name[entry->direction],
1131 dir2name[ref->direction]);
1132 }
1133
1134 if (entry->map_err_type == MAP_ERR_NOT_CHECKED) {
1135 err_printk(ref->dev, entry,
1136 "DMA-API: device driver failed to check map error"
1137 "[device address=0x%016llx] [size=%llu bytes] "
1138 "[mapped as %s]",
1139 ref->dev_addr, ref->size,
1140 type2name[entry->type]);
1141 }
1142
1143 hash_bucket_del(entry);
1144 dma_entry_free(entry);
1145
1146 put_hash_bucket(bucket, &flags);
1147}
1148
1149static void check_for_stack(struct device *dev, void *addr)
1150{
1151 if (object_is_on_stack(addr))
1152 err_printk(dev, NULL, "DMA-API: device driver maps memory from"
1153 "stack [addr=%p]\n", addr);
1154}
1155
1156static inline bool overlap(void *addr, unsigned long len, void *start, void *end)
1157{
1158 unsigned long a1 = (unsigned long)addr;
1159 unsigned long b1 = a1 + len;
1160 unsigned long a2 = (unsigned long)start;
1161 unsigned long b2 = (unsigned long)end;
1162
1163 return !(b1 <= a2 || a1 >= b2);
1164}
1165
1166static void check_for_illegal_area(struct device *dev, void *addr, unsigned long len)
1167{
1168 if (overlap(addr, len, _text, _etext) ||
1169 overlap(addr, len, __start_rodata, __end_rodata))
1170 err_printk(dev, NULL, "DMA-API: device driver maps memory from kernel text or rodata [addr=%p] [len=%lu]\n", addr, len);
1171}
1172
1173static void check_sync(struct device *dev,
1174 struct dma_debug_entry *ref,
1175 bool to_cpu)
1176{
1177 struct dma_debug_entry *entry;
1178 struct hash_bucket *bucket;
1179 unsigned long flags;
1180
1181 bucket = get_hash_bucket(ref, &flags);
1182
1183 entry = bucket_find_contain(&bucket, ref, &flags);
1184
1185 if (!entry) {
1186 err_printk(dev, NULL, "DMA-API: device driver tries "
1187 "to sync DMA memory it has not allocated "
1188 "[device address=0x%016llx] [size=%llu bytes]\n",
1189 (unsigned long long)ref->dev_addr, ref->size);
1190 goto out;
1191 }
1192
1193 if (ref->size > entry->size) {
1194 err_printk(dev, entry, "DMA-API: device driver syncs"
1195 " DMA memory outside allocated range "
1196 "[device address=0x%016llx] "
1197 "[allocation size=%llu bytes] "
1198 "[sync offset+size=%llu]\n",
1199 entry->dev_addr, entry->size,
1200 ref->size);
1201 }
1202
1203 if (entry->direction == DMA_BIDIRECTIONAL)
1204 goto out;
1205
1206 if (ref->direction != entry->direction) {
1207 err_printk(dev, entry, "DMA-API: device driver syncs "
1208 "DMA memory with different direction "
1209 "[device address=0x%016llx] [size=%llu bytes] "
1210 "[mapped with %s] [synced with %s]\n",
1211 (unsigned long long)ref->dev_addr, entry->size,
1212 dir2name[entry->direction],
1213 dir2name[ref->direction]);
1214 }
1215
1216 if (to_cpu && !(entry->direction == DMA_FROM_DEVICE) &&
1217 !(ref->direction == DMA_TO_DEVICE))
1218 err_printk(dev, entry, "DMA-API: device driver syncs "
1219 "device read-only DMA memory for cpu "
1220 "[device address=0x%016llx] [size=%llu bytes] "
1221 "[mapped with %s] [synced with %s]\n",
1222 (unsigned long long)ref->dev_addr, entry->size,
1223 dir2name[entry->direction],
1224 dir2name[ref->direction]);
1225
1226 if (!to_cpu && !(entry->direction == DMA_TO_DEVICE) &&
1227 !(ref->direction == DMA_FROM_DEVICE))
1228 err_printk(dev, entry, "DMA-API: device driver syncs "
1229 "device write-only DMA memory to device "
1230 "[device address=0x%016llx] [size=%llu bytes] "
1231 "[mapped with %s] [synced with %s]\n",
1232 (unsigned long long)ref->dev_addr, entry->size,
1233 dir2name[entry->direction],
1234 dir2name[ref->direction]);
1235
1236out:
1237 put_hash_bucket(bucket, &flags);
1238}
1239
1240void debug_dma_map_page(struct device *dev, struct page *page, size_t offset,
1241 size_t size, int direction, dma_addr_t dma_addr,
1242 bool map_single)
1243{
1244 struct dma_debug_entry *entry;
1245
1246 if (unlikely(global_disable))
1247 return;
1248
1249 if (dma_mapping_error(dev, dma_addr))
1250 return;
1251
1252 entry = dma_entry_alloc();
1253 if (!entry)
1254 return;
1255
1256 entry->dev = dev;
1257 entry->type = dma_debug_page;
1258 entry->pfn = page_to_pfn(page);
1259 entry->offset = offset,
1260 entry->dev_addr = dma_addr;
1261 entry->size = size;
1262 entry->direction = direction;
1263 entry->map_err_type = MAP_ERR_NOT_CHECKED;
1264
1265 if (map_single)
1266 entry->type = dma_debug_single;
1267
1268 if (!PageHighMem(page)) {
1269 void *addr = page_address(page) + offset;
1270
1271 check_for_stack(dev, addr);
1272 check_for_illegal_area(dev, addr, size);
1273 }
1274
1275 add_dma_entry(entry);
1276}
1277EXPORT_SYMBOL(debug_dma_map_page);
1278
1279void debug_dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
1280{
1281 struct dma_debug_entry ref;
1282 struct dma_debug_entry *entry;
1283 struct hash_bucket *bucket;
1284 unsigned long flags;
1285
1286 if (unlikely(global_disable))
1287 return;
1288
1289 ref.dev = dev;
1290 ref.dev_addr = dma_addr;
1291 bucket = get_hash_bucket(&ref, &flags);
1292
1293 list_for_each_entry(entry, &bucket->list, list) {
1294 if (!exact_match(&ref, entry))
1295 continue;
1296
1297 /*
1298 * The same physical address can be mapped multiple
1299 * times. Without a hardware IOMMU this results in the
1300 * same device addresses being put into the dma-debug
1301 * hash multiple times too. This can result in false
1302 * positives being reported. Therefore we implement a
1303 * best-fit algorithm here which updates the first entry
1304 * from the hash which fits the reference value and is
1305 * not currently listed as being checked.
1306 */
1307 if (entry->map_err_type == MAP_ERR_NOT_CHECKED) {
1308 entry->map_err_type = MAP_ERR_CHECKED;
1309 break;
1310 }
1311 }
1312
1313 put_hash_bucket(bucket, &flags);
1314}
1315EXPORT_SYMBOL(debug_dma_mapping_error);
1316
1317void debug_dma_unmap_page(struct device *dev, dma_addr_t addr,
1318 size_t size, int direction, bool map_single)
1319{
1320 struct dma_debug_entry ref = {
1321 .type = dma_debug_page,
1322 .dev = dev,
1323 .dev_addr = addr,
1324 .size = size,
1325 .direction = direction,
1326 };
1327
1328 if (unlikely(global_disable))
1329 return;
1330
1331 if (map_single)
1332 ref.type = dma_debug_single;
1333
1334 check_unmap(&ref);
1335}
1336EXPORT_SYMBOL(debug_dma_unmap_page);
1337
1338void debug_dma_map_sg(struct device *dev, struct scatterlist *sg,
1339 int nents, int mapped_ents, int direction)
1340{
1341 struct dma_debug_entry *entry;
1342 struct scatterlist *s;
1343 int i;
1344
1345 if (unlikely(global_disable))
1346 return;
1347
1348 for_each_sg(sg, s, mapped_ents, i) {
1349 entry = dma_entry_alloc();
1350 if (!entry)
1351 return;
1352
1353 entry->type = dma_debug_sg;
1354 entry->dev = dev;
1355 entry->pfn = page_to_pfn(sg_page(s));
1356 entry->offset = s->offset,
1357 entry->size = sg_dma_len(s);
1358 entry->dev_addr = sg_dma_address(s);
1359 entry->direction = direction;
1360 entry->sg_call_ents = nents;
1361 entry->sg_mapped_ents = mapped_ents;
1362
1363 if (!PageHighMem(sg_page(s))) {
1364 check_for_stack(dev, sg_virt(s));
1365 check_for_illegal_area(dev, sg_virt(s), sg_dma_len(s));
1366 }
1367
1368 add_dma_entry(entry);
1369 }
1370}
1371EXPORT_SYMBOL(debug_dma_map_sg);
1372
1373static int get_nr_mapped_entries(struct device *dev,
1374 struct dma_debug_entry *ref)
1375{
1376 struct dma_debug_entry *entry;
1377 struct hash_bucket *bucket;
1378 unsigned long flags;
1379 int mapped_ents;
1380
1381 bucket = get_hash_bucket(ref, &flags);
1382 entry = bucket_find_exact(bucket, ref);
1383 mapped_ents = 0;
1384
1385 if (entry)
1386 mapped_ents = entry->sg_mapped_ents;
1387 put_hash_bucket(bucket, &flags);
1388
1389 return mapped_ents;
1390}
1391
1392void debug_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
1393 int nelems, int dir)
1394{
1395 struct scatterlist *s;
1396 int mapped_ents = 0, i;
1397
1398 if (unlikely(global_disable))
1399 return;
1400
1401 for_each_sg(sglist, s, nelems, i) {
1402
1403 struct dma_debug_entry ref = {
1404 .type = dma_debug_sg,
1405 .dev = dev,
1406 .pfn = page_to_pfn(sg_page(s)),
1407 .offset = s->offset,
1408 .dev_addr = sg_dma_address(s),
1409 .size = sg_dma_len(s),
1410 .direction = dir,
1411 .sg_call_ents = nelems,
1412 };
1413
1414 if (mapped_ents && i >= mapped_ents)
1415 break;
1416
1417 if (!i)
1418 mapped_ents = get_nr_mapped_entries(dev, &ref);
1419
1420 check_unmap(&ref);
1421 }
1422}
1423EXPORT_SYMBOL(debug_dma_unmap_sg);
1424
1425void debug_dma_alloc_coherent(struct device *dev, size_t size,
1426 dma_addr_t dma_addr, void *virt)
1427{
1428 struct dma_debug_entry *entry;
1429
1430 if (unlikely(global_disable))
1431 return;
1432
1433 if (unlikely(virt == NULL))
1434 return;
1435
1436 entry = dma_entry_alloc();
1437 if (!entry)
1438 return;
1439
1440 entry->type = dma_debug_coherent;
1441 entry->dev = dev;
1442 entry->pfn = page_to_pfn(virt_to_page(virt));
1443 entry->offset = (size_t) virt & PAGE_MASK;
1444 entry->size = size;
1445 entry->dev_addr = dma_addr;
1446 entry->direction = DMA_BIDIRECTIONAL;
1447
1448 add_dma_entry(entry);
1449}
1450EXPORT_SYMBOL(debug_dma_alloc_coherent);
1451
1452void debug_dma_free_coherent(struct device *dev, size_t size,
1453 void *virt, dma_addr_t addr)
1454{
1455 struct dma_debug_entry ref = {
1456 .type = dma_debug_coherent,
1457 .dev = dev,
1458 .pfn = page_to_pfn(virt_to_page(virt)),
1459 .offset = (size_t) virt & PAGE_MASK,
1460 .dev_addr = addr,
1461 .size = size,
1462 .direction = DMA_BIDIRECTIONAL,
1463 };
1464
1465 if (unlikely(global_disable))
1466 return;
1467
1468 check_unmap(&ref);
1469}
1470EXPORT_SYMBOL(debug_dma_free_coherent);
1471
1472void debug_dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_handle,
1473 size_t size, int direction)
1474{
1475 struct dma_debug_entry ref;
1476
1477 if (unlikely(global_disable))
1478 return;
1479
1480 ref.type = dma_debug_single;
1481 ref.dev = dev;
1482 ref.dev_addr = dma_handle;
1483 ref.size = size;
1484 ref.direction = direction;
1485 ref.sg_call_ents = 0;
1486
1487 check_sync(dev, &ref, true);
1488}
1489EXPORT_SYMBOL(debug_dma_sync_single_for_cpu);
1490
1491void debug_dma_sync_single_for_device(struct device *dev,
1492 dma_addr_t dma_handle, size_t size,
1493 int direction)
1494{
1495 struct dma_debug_entry ref;
1496
1497 if (unlikely(global_disable))
1498 return;
1499
1500 ref.type = dma_debug_single;
1501 ref.dev = dev;
1502 ref.dev_addr = dma_handle;
1503 ref.size = size;
1504 ref.direction = direction;
1505 ref.sg_call_ents = 0;
1506
1507 check_sync(dev, &ref, false);
1508}
1509EXPORT_SYMBOL(debug_dma_sync_single_for_device);
1510
1511void debug_dma_sync_single_range_for_cpu(struct device *dev,
1512 dma_addr_t dma_handle,
1513 unsigned long offset, size_t size,
1514 int direction)
1515{
1516 struct dma_debug_entry ref;
1517
1518 if (unlikely(global_disable))
1519 return;
1520
1521 ref.type = dma_debug_single;
1522 ref.dev = dev;
1523 ref.dev_addr = dma_handle;
1524 ref.size = offset + size;
1525 ref.direction = direction;
1526 ref.sg_call_ents = 0;
1527
1528 check_sync(dev, &ref, true);
1529}
1530EXPORT_SYMBOL(debug_dma_sync_single_range_for_cpu);
1531
1532void debug_dma_sync_single_range_for_device(struct device *dev,
1533 dma_addr_t dma_handle,
1534 unsigned long offset,
1535 size_t size, int direction)
1536{
1537 struct dma_debug_entry ref;
1538
1539 if (unlikely(global_disable))
1540 return;
1541
1542 ref.type = dma_debug_single;
1543 ref.dev = dev;
1544 ref.dev_addr = dma_handle;
1545 ref.size = offset + size;
1546 ref.direction = direction;
1547 ref.sg_call_ents = 0;
1548
1549 check_sync(dev, &ref, false);
1550}
1551EXPORT_SYMBOL(debug_dma_sync_single_range_for_device);
1552
1553void debug_dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
1554 int nelems, int direction)
1555{
1556 struct scatterlist *s;
1557 int mapped_ents = 0, i;
1558
1559 if (unlikely(global_disable))
1560 return;
1561
1562 for_each_sg(sg, s, nelems, i) {
1563
1564 struct dma_debug_entry ref = {
1565 .type = dma_debug_sg,
1566 .dev = dev,
1567 .pfn = page_to_pfn(sg_page(s)),
1568 .offset = s->offset,
1569 .dev_addr = sg_dma_address(s),
1570 .size = sg_dma_len(s),
1571 .direction = direction,
1572 .sg_call_ents = nelems,
1573 };
1574
1575 if (!i)
1576 mapped_ents = get_nr_mapped_entries(dev, &ref);
1577
1578 if (i >= mapped_ents)
1579 break;
1580
1581 check_sync(dev, &ref, true);
1582 }
1583}
1584EXPORT_SYMBOL(debug_dma_sync_sg_for_cpu);
1585
1586void debug_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
1587 int nelems, int direction)
1588{
1589 struct scatterlist *s;
1590 int mapped_ents = 0, i;
1591
1592 if (unlikely(global_disable))
1593 return;
1594
1595 for_each_sg(sg, s, nelems, i) {
1596
1597 struct dma_debug_entry ref = {
1598 .type = dma_debug_sg,
1599 .dev = dev,
1600 .pfn = page_to_pfn(sg_page(s)),
1601 .offset = s->offset,
1602 .dev_addr = sg_dma_address(s),
1603 .size = sg_dma_len(s),
1604 .direction = direction,
1605 .sg_call_ents = nelems,
1606 };
1607 if (!i)
1608 mapped_ents = get_nr_mapped_entries(dev, &ref);
1609
1610 if (i >= mapped_ents)
1611 break;
1612
1613 check_sync(dev, &ref, false);
1614 }
1615}
1616EXPORT_SYMBOL(debug_dma_sync_sg_for_device);
1617
1618static int __init dma_debug_driver_setup(char *str)
1619{
1620 int i;
1621
1622 for (i = 0; i < NAME_MAX_LEN - 1; ++i, ++str) {
1623 current_driver_name[i] = *str;
1624 if (*str == 0)
1625 break;
1626 }
1627
1628 if (current_driver_name[0])
1629 pr_info("DMA-API: enable driver filter for driver [%s]\n",
1630 current_driver_name);
1631
1632
1633 return 1;
1634}
1635__setup("dma_debug_driver=", dma_debug_driver_setup);