projects/linux·blob v3.4-rc2 · refs

1365 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 bool 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/* 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 */
141static 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
151static 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 */
211static 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 */
223static 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 */
237static 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
245static 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
251static 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 */
267static 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
317static 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
323static 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 */
353static 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 */
362static 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 */
370void 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}
395EXPORT_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 */
401static 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
411static 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 */
431static 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
453out:
454 spin_unlock_irqrestore(&free_entries_lock, flags);
455
456 return entry;
457}
458
459static 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
473int 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}
518EXPORT_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
528static 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
548out_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
558static 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
580static 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
638out_unlock:
639 write_unlock_irqrestore(&driver_name_lock, flags);
640
641 return count;
642}
643
644static const struct file_operations filter_fops = {
645 .read = filter_read,
646 .write = filter_write,
647 .llseek = default_llseek,
648};
649
650static 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
700out_err:
701 debugfs_remove_recursive(dma_debug_dent);
702
703 return -ENOMEM;
704}
705
706static 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
730static 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
760void 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 */
781void 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
815static __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
828static __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
846static 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
921out:
922 put_hash_bucket(bucket, &flags);
923}
924
925static 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
932static 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
942static 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
949static 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
1012out:
1013 put_hash_bucket(bucket, &flags);
1014}
1015
1016void 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}
1051EXPORT_SYMBOL(debug_dma_map_page);
1052
1053void 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}
1072EXPORT_SYMBOL(debug_dma_unmap_page);
1073
1074void 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}
1106EXPORT_SYMBOL(debug_dma_map_sg);
1107
1108static 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
1127void 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}
1157EXPORT_SYMBOL(debug_dma_unmap_sg);
1158
1159void 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}
1183EXPORT_SYMBOL(debug_dma_alloc_coherent);
1184
1185void 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}
1202EXPORT_SYMBOL(debug_dma_free_coherent);
1203
1204void 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}
1221EXPORT_SYMBOL(debug_dma_sync_single_for_cpu);
1222
1223void 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}
1241EXPORT_SYMBOL(debug_dma_sync_single_for_device);
1242
1243void 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}
1262EXPORT_SYMBOL(debug_dma_sync_single_range_for_cpu);
1263
1264void 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}
1283EXPORT_SYMBOL(debug_dma_sync_single_range_for_device);
1284
1285void 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}
1315EXPORT_SYMBOL(debug_dma_sync_sg_for_cpu);
1316
1317void 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}
1346EXPORT_SYMBOL(debug_dma_sync_sg_for_device);
1347
1348static 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);