projects/linux·blob v3.7 · refs

1360 lines · 33.1 KiB

1/*
2 * Copyright (C) 2008 Advanced Micro Devices, Inc.
3 *
4 * Author: Joerg Roedel <[email protected]>
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
48#define DMA_DEBUG_STACKTRACE_ENTRIES 5
49
50struct 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
66typedef bool (*match_fn)(struct dma_debug_entry *, struct dma_debug_entry *);
67
68struct 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 */
74static struct hash_bucket dma_entry_hash[HASH_SIZE];
75/* List of pre-allocated dma_debug_entry's */
76static LIST_HEAD(free_entries);
77/* Lock for the list above */
78static DEFINE_SPINLOCK(free_entries_lock);
79
80/* Global disable flag - will be set in case of an error */
81static u32 global_disable __read_mostly;
82
83/* Global error count */
84static u32 error_count;
85
86/* Global error show enable*/
87static u32 show_all_errors __read_mostly;
88/* Number of errors to show */
89static u32 show_num_errors = 1;
90
91static u32 num_free_entries;
92static u32 min_free_entries;
93static u32 nr_total_entries;
94
95/* number of preallocated entries requested by kernel cmdline */
96static u32 req_entries;
97
98/* debugfs dentry's for the stuff above */
99static struct dentry *dma_debug_dent __read_mostly;
100static struct dentry *global_disable_dent __read_mostly;
101static struct dentry *error_count_dent __read_mostly;
102static struct dentry *show_all_errors_dent __read_mostly;
103static struct dentry *show_num_errors_dent __read_mostly;
104static struct dentry *num_free_entries_dent __read_mostly;
105static struct dentry *min_free_entries_dent __read_mostly;
106static struct dentry *filter_dent __read_mostly;
107
108/* per-driver filter related state */
109
110#define NAME_MAX_LEN 64
111
112static char current_driver_name[NAME_MAX_LEN] __read_mostly;
113static struct device_driver *current_driver __read_mostly;
114
115static DEFINE_RWLOCK(driver_name_lock);
116
117static const char *type2name[4] = { "single", "page",
118 "scather-gather", "coherent" };
119
120static const char *dir2name[4] = { "DMA_BIDIRECTIONAL", "DMA_TO_DEVICE",
121 "DMA_FROM_DEVICE", "DMA_NONE" };
122
123/*
124 * The access to some variables in this macro is racy. We can't use atomic_t
125 * here because all these variables are exported to debugfs. Some of them even
126 * writeable. This is also the reason why a lock won't help much. But anyway,
127 * the races are no big deal. Here is why:
128 *
129 * error_count: the addition is racy, but the worst thing that can happen is
130 * that we don't count some errors
131 * show_num_errors: the subtraction is racy. Also no big deal because in
132 * worst case this will result in one warning more in the
133 * system log than the user configured. This variable is
134 * writeable via debugfs.
135 */
136static inline void dump_entry_trace(struct dma_debug_entry *entry)
137{
138#ifdef CONFIG_STACKTRACE
139 if (entry) {
140 pr_warning("Mapped at:\n");
141 print_stack_trace(&entry->stacktrace, 0);
142 }
143#endif
144}
145
146static bool driver_filter(struct device *dev)
147{
148 struct device_driver *drv;
149 unsigned long flags;
150 bool ret;
151
152 /* driver filter off */
153 if (likely(!current_driver_name[0]))
154 return true;
155
156 /* driver filter on and initialized */
157 if (current_driver && dev && dev->driver == current_driver)
158 return true;
159
160 /* driver filter on, but we can't filter on a NULL device... */
161 if (!dev)
162 return false;
163
164 if (current_driver || !current_driver_name[0])
165 return false;
166
167 /* driver filter on but not yet initialized */
168 drv = dev->driver;
169 if (!drv)
170 return false;
171
172 /* lock to protect against change of current_driver_name */
173 read_lock_irqsave(&driver_name_lock, flags);
174
175 ret = false;
176 if (drv->name &&
177 strncmp(current_driver_name, drv->name, NAME_MAX_LEN - 1) == 0) {
178 current_driver = drv;
179 ret = true;
180 }
181
182 read_unlock_irqrestore(&driver_name_lock, flags);
183
184 return ret;
185}
186
187#define err_printk(dev, entry, format, arg...) do { \
188 error_count += 1; \
189 if (driver_filter(dev) && \
190 (show_all_errors || show_num_errors > 0)) { \
191 WARN(1, "%s %s: " format, \
192 dev ? dev_driver_string(dev) : "NULL", \
193 dev ? dev_name(dev) : "NULL", ## arg); \
194 dump_entry_trace(entry); \
195 } \
196 if (!show_all_errors && show_num_errors > 0) \
197 show_num_errors -= 1; \
198 } while (0);
199
200/*
201 * Hash related functions
202 *
203 * Every DMA-API request is saved into a struct dma_debug_entry. To
204 * have quick access to these structs they are stored into a hash.
205 */
206static int hash_fn(struct dma_debug_entry *entry)
207{
208 /*
209 * Hash function is based on the dma address.
210 * We use bits 20-27 here as the index into the hash
211 */
212 return (entry->dev_addr >> HASH_FN_SHIFT) & HASH_FN_MASK;
213}
214
215/*
216 * Request exclusive access to a hash bucket for a given dma_debug_entry.
217 */
218static struct hash_bucket *get_hash_bucket(struct dma_debug_entry *entry,
219 unsigned long *flags)
220{
221 int idx = hash_fn(entry);
222 unsigned long __flags;
223
224 spin_lock_irqsave(&dma_entry_hash[idx].lock, __flags);
225 *flags = __flags;
226 return &dma_entry_hash[idx];
227}
228
229/*
230 * Give up exclusive access to the hash bucket
231 */
232static void put_hash_bucket(struct hash_bucket *bucket,
233 unsigned long *flags)
234{
235 unsigned long __flags = *flags;
236
237 spin_unlock_irqrestore(&bucket->lock, __flags);
238}
239
240static bool exact_match(struct dma_debug_entry *a, struct dma_debug_entry *b)
241{
242 return ((a->dev_addr == b->dev_addr) &&
243 (a->dev == b->dev)) ? true : false;
244}
245
246static bool containing_match(struct dma_debug_entry *a,
247 struct dma_debug_entry *b)
248{
249 if (a->dev != b->dev)
250 return false;
251
252 if ((b->dev_addr <= a->dev_addr) &&
253 ((b->dev_addr + b->size) >= (a->dev_addr + a->size)))
254 return true;
255
256 return false;
257}
258
259/*
260 * Search a given entry in the hash bucket list
261 */
262static struct dma_debug_entry *__hash_bucket_find(struct hash_bucket *bucket,
263 struct dma_debug_entry *ref,
264 match_fn match)
265{
266 struct dma_debug_entry *entry, *ret = NULL;
267 int matches = 0, match_lvl, last_lvl = -1;
268
269 list_for_each_entry(entry, &bucket->list, list) {
270 if (!match(ref, entry))
271 continue;
272
273 /*
274 * Some drivers map the same physical address multiple
275 * times. Without a hardware IOMMU this results in the
276 * same device addresses being put into the dma-debug
277 * hash multiple times too. This can result in false
278 * positives being reported. Therefore we implement a
279 * best-fit algorithm here which returns the entry from
280 * the hash which fits best to the reference value
281 * instead of the first-fit.
282 */
283 matches += 1;
284 match_lvl = 0;
285 entry->size == ref->size ? ++match_lvl : 0;
286 entry->type == ref->type ? ++match_lvl : 0;
287 entry->direction == ref->direction ? ++match_lvl : 0;
288 entry->sg_call_ents == ref->sg_call_ents ? ++match_lvl : 0;
289
290 if (match_lvl == 4) {
291 /* perfect-fit - return the result */
292 return entry;
293 } else if (match_lvl > last_lvl) {
294 /*
295 * We found an entry that fits better then the
296 * previous one or it is the 1st match.
297 */
298 last_lvl = match_lvl;
299 ret = entry;
300 }
301 }
302
303 /*
304 * If we have multiple matches but no perfect-fit, just return
305 * NULL.
306 */
307 ret = (matches == 1) ? ret : NULL;
308
309 return ret;
310}
311
312static struct dma_debug_entry *bucket_find_exact(struct hash_bucket *bucket,
313 struct dma_debug_entry *ref)
314{
315 return __hash_bucket_find(bucket, ref, exact_match);
316}
317
318static struct dma_debug_entry *bucket_find_contain(struct hash_bucket **bucket,
319 struct dma_debug_entry *ref,
320 unsigned long *flags)
321{
322
323 unsigned int max_range = dma_get_max_seg_size(ref->dev);
324 struct dma_debug_entry *entry, index = *ref;
325 unsigned int range = 0;
326
327 while (range <= max_range) {
328 entry = __hash_bucket_find(*bucket, &index, containing_match);
329
330 if (entry)
331 return entry;
332
333 /*
334 * Nothing found, go back a hash bucket
335 */
336 put_hash_bucket(*bucket, flags);
337 range += (1 << HASH_FN_SHIFT);
338 index.dev_addr -= (1 << HASH_FN_SHIFT);
339 *bucket = get_hash_bucket(&index, flags);
340 }
341
342 return NULL;
343}
344
345/*
346 * Add an entry to a hash bucket
347 */
348static void hash_bucket_add(struct hash_bucket *bucket,
349 struct dma_debug_entry *entry)
350{
351 list_add_tail(&entry->list, &bucket->list);
352}
353
354/*
355 * Remove entry from a hash bucket list
356 */
357static void hash_bucket_del(struct dma_debug_entry *entry)
358{
359 list_del(&entry->list);
360}
361
362/*
363 * Dump mapping entries for debugging purposes
364 */
365void debug_dma_dump_mappings(struct device *dev)
366{
367 int idx;
368
369 for (idx = 0; idx < HASH_SIZE; idx++) {
370 struct hash_bucket *bucket = &dma_entry_hash[idx];
371 struct dma_debug_entry *entry;
372 unsigned long flags;
373
374 spin_lock_irqsave(&bucket->lock, flags);
375
376 list_for_each_entry(entry, &bucket->list, list) {
377 if (!dev || dev == entry->dev) {
378 dev_info(entry->dev,
379 "%s idx %d P=%Lx D=%Lx L=%Lx %s\n",
380 type2name[entry->type], idx,
381 (unsigned long long)entry->paddr,
382 entry->dev_addr, entry->size,
383 dir2name[entry->direction]);
384 }
385 }
386
387 spin_unlock_irqrestore(&bucket->lock, flags);
388 }
389}
390EXPORT_SYMBOL(debug_dma_dump_mappings);
391
392/*
393 * Wrapper function for adding an entry to the hash.
394 * This function takes care of locking itself.
395 */
396static void add_dma_entry(struct dma_debug_entry *entry)
397{
398 struct hash_bucket *bucket;
399 unsigned long flags;
400
401 bucket = get_hash_bucket(entry, &flags);
402 hash_bucket_add(bucket, entry);
403 put_hash_bucket(bucket, &flags);
404}
405
406static struct dma_debug_entry *__dma_entry_alloc(void)
407{
408 struct dma_debug_entry *entry;
409
410 entry = list_entry(free_entries.next, struct dma_debug_entry, list);
411 list_del(&entry->list);
412 memset(entry, 0, sizeof(*entry));
413
414 num_free_entries -= 1;
415 if (num_free_entries < min_free_entries)
416 min_free_entries = num_free_entries;
417
418 return entry;
419}
420
421/* struct dma_entry allocator
422 *
423 * The next two functions implement the allocator for
424 * struct dma_debug_entries.
425 */
426static struct dma_debug_entry *dma_entry_alloc(void)
427{
428 struct dma_debug_entry *entry;
429 unsigned long flags;
430
431 spin_lock_irqsave(&free_entries_lock, flags);
432
433 if (list_empty(&free_entries)) {
434 pr_err("DMA-API: debugging out of memory - disabling\n");
435 global_disable = true;
436 spin_unlock_irqrestore(&free_entries_lock, flags);
437 return NULL;
438 }
439
440 entry = __dma_entry_alloc();
441
442 spin_unlock_irqrestore(&free_entries_lock, flags);
443
444#ifdef CONFIG_STACKTRACE
445 entry->stacktrace.max_entries = DMA_DEBUG_STACKTRACE_ENTRIES;
446 entry->stacktrace.entries = entry->st_entries;
447 entry->stacktrace.skip = 2;
448 save_stack_trace(&entry->stacktrace);
449#endif
450
451 return entry;
452}
453
454static void dma_entry_free(struct dma_debug_entry *entry)
455{
456 unsigned long flags;
457
458 /*
459 * add to beginning of the list - this way the entries are
460 * more likely cache hot when they are reallocated.
461 */
462 spin_lock_irqsave(&free_entries_lock, flags);
463 list_add(&entry->list, &free_entries);
464 num_free_entries += 1;
465 spin_unlock_irqrestore(&free_entries_lock, flags);
466}
467
468int dma_debug_resize_entries(u32 num_entries)
469{
470 int i, delta, ret = 0;
471 unsigned long flags;
472 struct dma_debug_entry *entry;
473 LIST_HEAD(tmp);
474
475 spin_lock_irqsave(&free_entries_lock, flags);
476
477 if (nr_total_entries < num_entries) {
478 delta = num_entries - nr_total_entries;
479
480 spin_unlock_irqrestore(&free_entries_lock, flags);
481
482 for (i = 0; i < delta; i++) {
483 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
484 if (!entry)
485 break;
486
487 list_add_tail(&entry->list, &tmp);
488 }
489
490 spin_lock_irqsave(&free_entries_lock, flags);
491
492 list_splice(&tmp, &free_entries);
493 nr_total_entries += i;
494 num_free_entries += i;
495 } else {
496 delta = nr_total_entries - num_entries;
497
498 for (i = 0; i < delta && !list_empty(&free_entries); i++) {
499 entry = __dma_entry_alloc();
500 kfree(entry);
501 }
502
503 nr_total_entries -= i;
504 }
505
506 if (nr_total_entries != num_entries)
507 ret = 1;
508
509 spin_unlock_irqrestore(&free_entries_lock, flags);
510
511 return ret;
512}
513EXPORT_SYMBOL(dma_debug_resize_entries);
514
515/*
516 * DMA-API debugging init code
517 *
518 * The init code does two things:
519 * 1. Initialize core data structures
520 * 2. Preallocate a given number of dma_debug_entry structs
521 */
522
523static int prealloc_memory(u32 num_entries)
524{
525 struct dma_debug_entry *entry, *next_entry;
526 int i;
527
528 for (i = 0; i < num_entries; ++i) {
529 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
530 if (!entry)
531 goto out_err;
532
533 list_add_tail(&entry->list, &free_entries);
534 }
535
536 num_free_entries = num_entries;
537 min_free_entries = num_entries;
538
539 pr_info("DMA-API: preallocated %d debug entries\n", num_entries);
540
541 return 0;
542
543out_err:
544
545 list_for_each_entry_safe(entry, next_entry, &free_entries, list) {
546 list_del(&entry->list);
547 kfree(entry);
548 }
549
550 return -ENOMEM;
551}
552
553static ssize_t filter_read(struct file *file, char __user *user_buf,
554 size_t count, loff_t *ppos)
555{
556 char buf[NAME_MAX_LEN + 1];
557 unsigned long flags;
558 int len;
559
560 if (!current_driver_name[0])
561 return 0;
562
563 /*
564 * We can't copy to userspace directly because current_driver_name can
565 * only be read under the driver_name_lock with irqs disabled. So
566 * create a temporary copy first.
567 */
568 read_lock_irqsave(&driver_name_lock, flags);
569 len = scnprintf(buf, NAME_MAX_LEN + 1, "%s\n", current_driver_name);
570 read_unlock_irqrestore(&driver_name_lock, flags);
571
572 return simple_read_from_buffer(user_buf, count, ppos, buf, len);
573}
574
575static ssize_t filter_write(struct file *file, const char __user *userbuf,
576 size_t count, loff_t *ppos)
577{
578 char buf[NAME_MAX_LEN];
579 unsigned long flags;
580 size_t len;
581 int i;
582
583 /*
584 * We can't copy from userspace directly. Access to
585 * current_driver_name is protected with a write_lock with irqs
586 * disabled. Since copy_from_user can fault and may sleep we
587 * need to copy to temporary buffer first
588 */
589 len = min(count, (size_t)(NAME_MAX_LEN - 1));
590 if (copy_from_user(buf, userbuf, len))
591 return -EFAULT;
592
593 buf[len] = 0;
594
595 write_lock_irqsave(&driver_name_lock, flags);
596
597 /*
598 * Now handle the string we got from userspace very carefully.
599 * The rules are:
600 * - only use the first token we got
601 * - token delimiter is everything looking like a space
602 * character (' ', '\n', '\t' ...)
603 *
604 */
605 if (!isalnum(buf[0])) {
606 /*
607 * If the first character userspace gave us is not
608 * alphanumerical then assume the filter should be
609 * switched off.
610 */
611 if (current_driver_name[0])
612 pr_info("DMA-API: switching off dma-debug driver filter\n");
613 current_driver_name[0] = 0;
614 current_driver = NULL;
615 goto out_unlock;
616 }
617
618 /*
619 * Now parse out the first token and use it as the name for the
620 * driver to filter for.
621 */
622 for (i = 0; i < NAME_MAX_LEN - 1; ++i) {
623 current_driver_name[i] = buf[i];
624 if (isspace(buf[i]) || buf[i] == ' ' || buf[i] == 0)
625 break;
626 }
627 current_driver_name[i] = 0;
628 current_driver = NULL;
629
630 pr_info("DMA-API: enable driver filter for driver [%s]\n",
631 current_driver_name);
632
633out_unlock:
634 write_unlock_irqrestore(&driver_name_lock, flags);
635
636 return count;
637}
638
639static const struct file_operations filter_fops = {
640 .read = filter_read,
641 .write = filter_write,
642 .llseek = default_llseek,
643};
644
645static int dma_debug_fs_init(void)
646{
647 dma_debug_dent = debugfs_create_dir("dma-api", NULL);
648 if (!dma_debug_dent) {
649 pr_err("DMA-API: can not create debugfs directory\n");
650 return -ENOMEM;
651 }
652
653 global_disable_dent = debugfs_create_bool("disabled", 0444,
654 dma_debug_dent,
655 &global_disable);
656 if (!global_disable_dent)
657 goto out_err;
658
659 error_count_dent = debugfs_create_u32("error_count", 0444,
660 dma_debug_dent, &error_count);
661 if (!error_count_dent)
662 goto out_err;
663
664 show_all_errors_dent = debugfs_create_u32("all_errors", 0644,
665 dma_debug_dent,
666 &show_all_errors);
667 if (!show_all_errors_dent)
668 goto out_err;
669
670 show_num_errors_dent = debugfs_create_u32("num_errors", 0644,
671 dma_debug_dent,
672 &show_num_errors);
673 if (!show_num_errors_dent)
674 goto out_err;
675
676 num_free_entries_dent = debugfs_create_u32("num_free_entries", 0444,
677 dma_debug_dent,
678 &num_free_entries);
679 if (!num_free_entries_dent)
680 goto out_err;
681
682 min_free_entries_dent = debugfs_create_u32("min_free_entries", 0444,
683 dma_debug_dent,
684 &min_free_entries);
685 if (!min_free_entries_dent)
686 goto out_err;
687
688 filter_dent = debugfs_create_file("driver_filter", 0644,
689 dma_debug_dent, NULL, &filter_fops);
690 if (!filter_dent)
691 goto out_err;
692
693 return 0;
694
695out_err:
696 debugfs_remove_recursive(dma_debug_dent);
697
698 return -ENOMEM;
699}
700
701static int device_dma_allocations(struct device *dev, struct dma_debug_entry **out_entry)
702{
703 struct dma_debug_entry *entry;
704 unsigned long flags;
705 int count = 0, i;
706
707 local_irq_save(flags);
708
709 for (i = 0; i < HASH_SIZE; ++i) {
710 spin_lock(&dma_entry_hash[i].lock);
711 list_for_each_entry(entry, &dma_entry_hash[i].list, list) {
712 if (entry->dev == dev) {
713 count += 1;
714 *out_entry = entry;
715 }
716 }
717 spin_unlock(&dma_entry_hash[i].lock);
718 }
719
720 local_irq_restore(flags);
721
722 return count;
723}
724
725static int dma_debug_device_change(struct notifier_block *nb, unsigned long action, void *data)
726{
727 struct device *dev = data;
728 struct dma_debug_entry *uninitialized_var(entry);
729 int count;
730
731 if (global_disable)
732 return 0;
733
734 switch (action) {
735 case BUS_NOTIFY_UNBOUND_DRIVER:
736 count = device_dma_allocations(dev, &entry);
737 if (count == 0)
738 break;
739 err_printk(dev, entry, "DMA-API: device driver has pending "
740 "DMA allocations while released from device "
741 "[count=%d]\n"
742 "One of leaked entries details: "
743 "[device address=0x%016llx] [size=%llu bytes] "
744 "[mapped with %s] [mapped as %s]\n",
745 count, entry->dev_addr, entry->size,
746 dir2name[entry->direction], type2name[entry->type]);
747 break;
748 default:
749 break;
750 }
751
752 return 0;
753}
754
755void dma_debug_add_bus(struct bus_type *bus)
756{
757 struct notifier_block *nb;
758
759 if (global_disable)
760 return;
761
762 nb = kzalloc(sizeof(struct notifier_block), GFP_KERNEL);
763 if (nb == NULL) {
764 pr_err("dma_debug_add_bus: out of memory\n");
765 return;
766 }
767
768 nb->notifier_call = dma_debug_device_change;
769
770 bus_register_notifier(bus, nb);
771}
772
773/*
774 * Let the architectures decide how many entries should be preallocated.
775 */
776void dma_debug_init(u32 num_entries)
777{
778 int i;
779
780 if (global_disable)
781 return;
782
783 for (i = 0; i < HASH_SIZE; ++i) {
784 INIT_LIST_HEAD(&dma_entry_hash[i].list);
785 spin_lock_init(&dma_entry_hash[i].lock);
786 }
787
788 if (dma_debug_fs_init() != 0) {
789 pr_err("DMA-API: error creating debugfs entries - disabling\n");
790 global_disable = true;
791
792 return;
793 }
794
795 if (req_entries)
796 num_entries = req_entries;
797
798 if (prealloc_memory(num_entries) != 0) {
799 pr_err("DMA-API: debugging out of memory error - disabled\n");
800 global_disable = true;
801
802 return;
803 }
804
805 nr_total_entries = num_free_entries;
806
807 pr_info("DMA-API: debugging enabled by kernel config\n");
808}
809
810static __init int dma_debug_cmdline(char *str)
811{
812 if (!str)
813 return -EINVAL;
814
815 if (strncmp(str, "off", 3) == 0) {
816 pr_info("DMA-API: debugging disabled on kernel command line\n");
817 global_disable = true;
818 }
819
820 return 0;
821}
822
823static __init int dma_debug_entries_cmdline(char *str)
824{
825 int res;
826
827 if (!str)
828 return -EINVAL;
829
830 res = get_option(&str, &req_entries);
831
832 if (!res)
833 req_entries = 0;
834
835 return 0;
836}
837
838__setup("dma_debug=", dma_debug_cmdline);
839__setup("dma_debug_entries=", dma_debug_entries_cmdline);
840
841static void check_unmap(struct dma_debug_entry *ref)
842{
843 struct dma_debug_entry *entry;
844 struct hash_bucket *bucket;
845 unsigned long flags;
846
847 if (dma_mapping_error(ref->dev, ref->dev_addr)) {
848 err_printk(ref->dev, NULL, "DMA-API: device driver tries "
849 "to free an invalid DMA memory address\n");
850 return;
851 }
852
853 bucket = get_hash_bucket(ref, &flags);
854 entry = bucket_find_exact(bucket, ref);
855
856 if (!entry) {
857 err_printk(ref->dev, NULL, "DMA-API: device driver tries "
858 "to free DMA memory it has not allocated "
859 "[device address=0x%016llx] [size=%llu bytes]\n",
860 ref->dev_addr, ref->size);
861 goto out;
862 }
863
864 if (ref->size != entry->size) {
865 err_printk(ref->dev, entry, "DMA-API: device driver frees "
866 "DMA memory with different size "
867 "[device address=0x%016llx] [map size=%llu bytes] "
868 "[unmap size=%llu bytes]\n",
869 ref->dev_addr, entry->size, ref->size);
870 }
871
872 if (ref->type != entry->type) {
873 err_printk(ref->dev, entry, "DMA-API: device driver frees "
874 "DMA memory with wrong function "
875 "[device address=0x%016llx] [size=%llu bytes] "
876 "[mapped as %s] [unmapped as %s]\n",
877 ref->dev_addr, ref->size,
878 type2name[entry->type], type2name[ref->type]);
879 } else if ((entry->type == dma_debug_coherent) &&
880 (ref->paddr != entry->paddr)) {
881 err_printk(ref->dev, entry, "DMA-API: device driver frees "
882 "DMA memory with different CPU address "
883 "[device address=0x%016llx] [size=%llu bytes] "
884 "[cpu alloc address=0x%016llx] "
885 "[cpu free address=0x%016llx]",
886 ref->dev_addr, ref->size,
887 (unsigned long long)entry->paddr,
888 (unsigned long long)ref->paddr);
889 }
890
891 if (ref->sg_call_ents && ref->type == dma_debug_sg &&
892 ref->sg_call_ents != entry->sg_call_ents) {
893 err_printk(ref->dev, entry, "DMA-API: device driver frees "
894 "DMA sg list with different entry count "
895 "[map count=%d] [unmap count=%d]\n",
896 entry->sg_call_ents, ref->sg_call_ents);
897 }
898
899 /*
900 * This may be no bug in reality - but most implementations of the
901 * DMA API don't handle this properly, so check for it here
902 */
903 if (ref->direction != entry->direction) {
904 err_printk(ref->dev, entry, "DMA-API: device driver frees "
905 "DMA memory with different direction "
906 "[device address=0x%016llx] [size=%llu bytes] "
907 "[mapped with %s] [unmapped with %s]\n",
908 ref->dev_addr, ref->size,
909 dir2name[entry->direction],
910 dir2name[ref->direction]);
911 }
912
913 hash_bucket_del(entry);
914 dma_entry_free(entry);
915
916out:
917 put_hash_bucket(bucket, &flags);
918}
919
920static void check_for_stack(struct device *dev, void *addr)
921{
922 if (object_is_on_stack(addr))
923 err_printk(dev, NULL, "DMA-API: device driver maps memory from"
924 "stack [addr=%p]\n", addr);
925}
926
927static inline bool overlap(void *addr, unsigned long len, void *start, void *end)
928{
929 unsigned long a1 = (unsigned long)addr;
930 unsigned long b1 = a1 + len;
931 unsigned long a2 = (unsigned long)start;
932 unsigned long b2 = (unsigned long)end;
933
934 return !(b1 <= a2 || a1 >= b2);
935}
936
937static void check_for_illegal_area(struct device *dev, void *addr, unsigned long len)
938{
939 if (overlap(addr, len, _text, _etext) ||
940 overlap(addr, len, __start_rodata, __end_rodata))
941 err_printk(dev, NULL, "DMA-API: device driver maps memory from kernel text or rodata [addr=%p] [len=%lu]\n", addr, len);
942}
943
944static void check_sync(struct device *dev,
945 struct dma_debug_entry *ref,
946 bool to_cpu)
947{
948 struct dma_debug_entry *entry;
949 struct hash_bucket *bucket;
950 unsigned long flags;
951
952 bucket = get_hash_bucket(ref, &flags);
953
954 entry = bucket_find_contain(&bucket, ref, &flags);
955
956 if (!entry) {
957 err_printk(dev, NULL, "DMA-API: device driver tries "
958 "to sync DMA memory it has not allocated "
959 "[device address=0x%016llx] [size=%llu bytes]\n",
960 (unsigned long long)ref->dev_addr, ref->size);
961 goto out;
962 }
963
964 if (ref->size > entry->size) {
965 err_printk(dev, entry, "DMA-API: device driver syncs"
966 " DMA memory outside allocated range "
967 "[device address=0x%016llx] "
968 "[allocation size=%llu bytes] "
969 "[sync offset+size=%llu]\n",
970 entry->dev_addr, entry->size,
971 ref->size);
972 }
973
974 if (entry->direction == DMA_BIDIRECTIONAL)
975 goto out;
976
977 if (ref->direction != entry->direction) {
978 err_printk(dev, entry, "DMA-API: device driver syncs "
979 "DMA memory with different direction "
980 "[device address=0x%016llx] [size=%llu bytes] "
981 "[mapped with %s] [synced with %s]\n",
982 (unsigned long long)ref->dev_addr, entry->size,
983 dir2name[entry->direction],
984 dir2name[ref->direction]);
985 }
986
987 if (to_cpu && !(entry->direction == DMA_FROM_DEVICE) &&
988 !(ref->direction == DMA_TO_DEVICE))
989 err_printk(dev, entry, "DMA-API: device driver syncs "
990 "device read-only DMA memory for cpu "
991 "[device address=0x%016llx] [size=%llu bytes] "
992 "[mapped with %s] [synced with %s]\n",
993 (unsigned long long)ref->dev_addr, entry->size,
994 dir2name[entry->direction],
995 dir2name[ref->direction]);
996
997 if (!to_cpu && !(entry->direction == DMA_TO_DEVICE) &&
998 !(ref->direction == DMA_FROM_DEVICE))
999 err_printk(dev, entry, "DMA-API: device driver syncs "
1000 "device write-only DMA memory to device "
1001 "[device address=0x%016llx] [size=%llu bytes] "
1002 "[mapped with %s] [synced with %s]\n",
1003 (unsigned long long)ref->dev_addr, entry->size,
1004 dir2name[entry->direction],
1005 dir2name[ref->direction]);
1006
1007out:
1008 put_hash_bucket(bucket, &flags);
1009}
1010
1011void debug_dma_map_page(struct device *dev, struct page *page, size_t offset,
1012 size_t size, int direction, dma_addr_t dma_addr,
1013 bool map_single)
1014{
1015 struct dma_debug_entry *entry;
1016
1017 if (unlikely(global_disable))
1018 return;
1019
1020 if (unlikely(dma_mapping_error(dev, dma_addr)))
1021 return;
1022
1023 entry = dma_entry_alloc();
1024 if (!entry)
1025 return;
1026
1027 entry->dev = dev;
1028 entry->type = dma_debug_page;
1029 entry->paddr = page_to_phys(page) + offset;
1030 entry->dev_addr = dma_addr;
1031 entry->size = size;
1032 entry->direction = direction;
1033
1034 if (map_single)
1035 entry->type = dma_debug_single;
1036
1037 if (!PageHighMem(page)) {
1038 void *addr = page_address(page) + offset;
1039
1040 check_for_stack(dev, addr);
1041 check_for_illegal_area(dev, addr, size);
1042 }
1043
1044 add_dma_entry(entry);
1045}
1046EXPORT_SYMBOL(debug_dma_map_page);
1047
1048void debug_dma_unmap_page(struct device *dev, dma_addr_t addr,
1049 size_t size, int direction, bool map_single)
1050{
1051 struct dma_debug_entry ref = {
1052 .type = dma_debug_page,
1053 .dev = dev,
1054 .dev_addr = addr,
1055 .size = size,
1056 .direction = direction,
1057 };
1058
1059 if (unlikely(global_disable))
1060 return;
1061
1062 if (map_single)
1063 ref.type = dma_debug_single;
1064
1065 check_unmap(&ref);
1066}
1067EXPORT_SYMBOL(debug_dma_unmap_page);
1068
1069void debug_dma_map_sg(struct device *dev, struct scatterlist *sg,
1070 int nents, int mapped_ents, int direction)
1071{
1072 struct dma_debug_entry *entry;
1073 struct scatterlist *s;
1074 int i;
1075
1076 if (unlikely(global_disable))
1077 return;
1078
1079 for_each_sg(sg, s, mapped_ents, i) {
1080 entry = dma_entry_alloc();
1081 if (!entry)
1082 return;
1083
1084 entry->type = dma_debug_sg;
1085 entry->dev = dev;
1086 entry->paddr = sg_phys(s);
1087 entry->size = sg_dma_len(s);
1088 entry->dev_addr = sg_dma_address(s);
1089 entry->direction = direction;
1090 entry->sg_call_ents = nents;
1091 entry->sg_mapped_ents = mapped_ents;
1092
1093 if (!PageHighMem(sg_page(s))) {
1094 check_for_stack(dev, sg_virt(s));
1095 check_for_illegal_area(dev, sg_virt(s), sg_dma_len(s));
1096 }
1097
1098 add_dma_entry(entry);
1099 }
1100}
1101EXPORT_SYMBOL(debug_dma_map_sg);
1102
1103static int get_nr_mapped_entries(struct device *dev,
1104 struct dma_debug_entry *ref)
1105{
1106 struct dma_debug_entry *entry;
1107 struct hash_bucket *bucket;
1108 unsigned long flags;
1109 int mapped_ents;
1110
1111 bucket = get_hash_bucket(ref, &flags);
1112 entry = bucket_find_exact(bucket, ref);
1113 mapped_ents = 0;
1114
1115 if (entry)
1116 mapped_ents = entry->sg_mapped_ents;
1117 put_hash_bucket(bucket, &flags);
1118
1119 return mapped_ents;
1120}
1121
1122void debug_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
1123 int nelems, int dir)
1124{
1125 struct scatterlist *s;
1126 int mapped_ents = 0, i;
1127
1128 if (unlikely(global_disable))
1129 return;
1130
1131 for_each_sg(sglist, s, nelems, i) {
1132
1133 struct dma_debug_entry ref = {
1134 .type = dma_debug_sg,
1135 .dev = dev,
1136 .paddr = sg_phys(s),
1137 .dev_addr = sg_dma_address(s),
1138 .size = sg_dma_len(s),
1139 .direction = dir,
1140 .sg_call_ents = nelems,
1141 };
1142
1143 if (mapped_ents && i >= mapped_ents)
1144 break;
1145
1146 if (!i)
1147 mapped_ents = get_nr_mapped_entries(dev, &ref);
1148
1149 check_unmap(&ref);
1150 }
1151}
1152EXPORT_SYMBOL(debug_dma_unmap_sg);
1153
1154void debug_dma_alloc_coherent(struct device *dev, size_t size,
1155 dma_addr_t dma_addr, void *virt)
1156{
1157 struct dma_debug_entry *entry;
1158
1159 if (unlikely(global_disable))
1160 return;
1161
1162 if (unlikely(virt == NULL))
1163 return;
1164
1165 entry = dma_entry_alloc();
1166 if (!entry)
1167 return;
1168
1169 entry->type = dma_debug_coherent;
1170 entry->dev = dev;
1171 entry->paddr = virt_to_phys(virt);
1172 entry->size = size;
1173 entry->dev_addr = dma_addr;
1174 entry->direction = DMA_BIDIRECTIONAL;
1175
1176 add_dma_entry(entry);
1177}
1178EXPORT_SYMBOL(debug_dma_alloc_coherent);
1179
1180void debug_dma_free_coherent(struct device *dev, size_t size,
1181 void *virt, dma_addr_t addr)
1182{
1183 struct dma_debug_entry ref = {
1184 .type = dma_debug_coherent,
1185 .dev = dev,
1186 .paddr = virt_to_phys(virt),
1187 .dev_addr = addr,
1188 .size = size,
1189 .direction = DMA_BIDIRECTIONAL,
1190 };
1191
1192 if (unlikely(global_disable))
1193 return;
1194
1195 check_unmap(&ref);
1196}
1197EXPORT_SYMBOL(debug_dma_free_coherent);
1198
1199void debug_dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_handle,
1200 size_t size, int direction)
1201{
1202 struct dma_debug_entry ref;
1203
1204 if (unlikely(global_disable))
1205 return;
1206
1207 ref.type = dma_debug_single;
1208 ref.dev = dev;
1209 ref.dev_addr = dma_handle;
1210 ref.size = size;
1211 ref.direction = direction;
1212 ref.sg_call_ents = 0;
1213
1214 check_sync(dev, &ref, true);
1215}
1216EXPORT_SYMBOL(debug_dma_sync_single_for_cpu);
1217
1218void debug_dma_sync_single_for_device(struct device *dev,
1219 dma_addr_t dma_handle, size_t size,
1220 int direction)
1221{
1222 struct dma_debug_entry ref;
1223
1224 if (unlikely(global_disable))
1225 return;
1226
1227 ref.type = dma_debug_single;
1228 ref.dev = dev;
1229 ref.dev_addr = dma_handle;
1230 ref.size = size;
1231 ref.direction = direction;
1232 ref.sg_call_ents = 0;
1233
1234 check_sync(dev, &ref, false);
1235}
1236EXPORT_SYMBOL(debug_dma_sync_single_for_device);
1237
1238void debug_dma_sync_single_range_for_cpu(struct device *dev,
1239 dma_addr_t dma_handle,
1240 unsigned long offset, size_t size,
1241 int direction)
1242{
1243 struct dma_debug_entry ref;
1244
1245 if (unlikely(global_disable))
1246 return;
1247
1248 ref.type = dma_debug_single;
1249 ref.dev = dev;
1250 ref.dev_addr = dma_handle;
1251 ref.size = offset + size;
1252 ref.direction = direction;
1253 ref.sg_call_ents = 0;
1254
1255 check_sync(dev, &ref, true);
1256}
1257EXPORT_SYMBOL(debug_dma_sync_single_range_for_cpu);
1258
1259void debug_dma_sync_single_range_for_device(struct device *dev,
1260 dma_addr_t dma_handle,
1261 unsigned long offset,
1262 size_t size, int direction)
1263{
1264 struct dma_debug_entry ref;
1265
1266 if (unlikely(global_disable))
1267 return;
1268
1269 ref.type = dma_debug_single;
1270 ref.dev = dev;
1271 ref.dev_addr = dma_handle;
1272 ref.size = offset + size;
1273 ref.direction = direction;
1274 ref.sg_call_ents = 0;
1275
1276 check_sync(dev, &ref, false);
1277}
1278EXPORT_SYMBOL(debug_dma_sync_single_range_for_device);
1279
1280void debug_dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
1281 int nelems, int direction)
1282{
1283 struct scatterlist *s;
1284 int mapped_ents = 0, i;
1285
1286 if (unlikely(global_disable))
1287 return;
1288
1289 for_each_sg(sg, s, nelems, i) {
1290
1291 struct dma_debug_entry ref = {
1292 .type = dma_debug_sg,
1293 .dev = dev,
1294 .paddr = sg_phys(s),
1295 .dev_addr = sg_dma_address(s),
1296 .size = sg_dma_len(s),
1297 .direction = direction,
1298 .sg_call_ents = nelems,
1299 };
1300
1301 if (!i)
1302 mapped_ents = get_nr_mapped_entries(dev, &ref);
1303
1304 if (i >= mapped_ents)
1305 break;
1306
1307 check_sync(dev, &ref, true);
1308 }
1309}
1310EXPORT_SYMBOL(debug_dma_sync_sg_for_cpu);
1311
1312void debug_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
1313 int nelems, int direction)
1314{
1315 struct scatterlist *s;
1316 int mapped_ents = 0, i;
1317
1318 if (unlikely(global_disable))
1319 return;
1320
1321 for_each_sg(sg, s, nelems, i) {
1322
1323 struct dma_debug_entry ref = {
1324 .type = dma_debug_sg,
1325 .dev = dev,
1326 .paddr = sg_phys(s),
1327 .dev_addr = sg_dma_address(s),
1328 .size = sg_dma_len(s),
1329 .direction = direction,
1330 .sg_call_ents = nelems,
1331 };
1332 if (!i)
1333 mapped_ents = get_nr_mapped_entries(dev, &ref);
1334
1335 if (i >= mapped_ents)
1336 break;
1337
1338 check_sync(dev, &ref, false);
1339 }
1340}
1341EXPORT_SYMBOL(debug_dma_sync_sg_for_device);
1342
1343static int __init dma_debug_driver_setup(char *str)
1344{
1345 int i;
1346
1347 for (i = 0; i < NAME_MAX_LEN - 1; ++i, ++str) {
1348 current_driver_name[i] = *str;
1349 if (*str == 0)
1350 break;
1351 }
1352
1353 if (current_driver_name[0])
1354 pr_info("DMA-API: enable driver filter for driver [%s]\n",
1355 current_driver_name);
1356
1357
1358 return 1;
1359}
1360__setup("dma_debug_driver=", dma_debug_driver_setup);