projects/linux·blob v3.3-rc3 · refs

1366 lines · 33.2 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 = get_driver(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 put_driver(drv);
189
190 return ret;
191}
192
193#define err_printk(dev, entry, format, arg...) do { \
194 error_count += 1; \
195 if (driver_filter(dev) && \
196 (show_all_errors || show_num_errors > 0)) { \
197 WARN(1, "%s %s: " format, \
198 dev ? dev_driver_string(dev) : "NULL", \
199 dev ? dev_name(dev) : "NULL", ## arg); \
200 dump_entry_trace(entry); \
201 } \
202 if (!show_all_errors && show_num_errors > 0) \
203 show_num_errors -= 1; \
204 } while (0);
205
206/*
207 * Hash related functions
208 *
209 * Every DMA-API request is saved into a struct dma_debug_entry. To
210 * have quick access to these structs they are stored into a hash.
211 */
212static int hash_fn(struct dma_debug_entry *entry)
213{
214 /*
215 * Hash function is based on the dma address.
216 * We use bits 20-27 here as the index into the hash
217 */
218 return (entry->dev_addr >> HASH_FN_SHIFT) & HASH_FN_MASK;
219}
220
221/*
222 * Request exclusive access to a hash bucket for a given dma_debug_entry.
223 */
224static struct hash_bucket *get_hash_bucket(struct dma_debug_entry *entry,
225 unsigned long *flags)
226{
227 int idx = hash_fn(entry);
228 unsigned long __flags;
229
230 spin_lock_irqsave(&dma_entry_hash[idx].lock, __flags);
231 *flags = __flags;
232 return &dma_entry_hash[idx];
233}
234
235/*
236 * Give up exclusive access to the hash bucket
237 */
238static void put_hash_bucket(struct hash_bucket *bucket,
239 unsigned long *flags)
240{
241 unsigned long __flags = *flags;
242
243 spin_unlock_irqrestore(&bucket->lock, __flags);
244}
245
246static bool exact_match(struct dma_debug_entry *a, struct dma_debug_entry *b)
247{
248 return ((a->dev_addr == b->dev_addr) &&
249 (a->dev == b->dev)) ? true : false;
250}
251
252static bool containing_match(struct dma_debug_entry *a,
253 struct dma_debug_entry *b)
254{
255 if (a->dev != b->dev)
256 return false;
257
258 if ((b->dev_addr <= a->dev_addr) &&
259 ((b->dev_addr + b->size) >= (a->dev_addr + a->size)))
260 return true;
261
262 return false;
263}
264
265/*
266 * Search a given entry in the hash bucket list
267 */
268static struct dma_debug_entry *__hash_bucket_find(struct hash_bucket *bucket,
269 struct dma_debug_entry *ref,
270 match_fn match)
271{
272 struct dma_debug_entry *entry, *ret = NULL;
273 int matches = 0, match_lvl, last_lvl = 0;
274
275 list_for_each_entry(entry, &bucket->list, list) {
276 if (!match(ref, entry))
277 continue;
278
279 /*
280 * Some drivers map the same physical address multiple
281 * times. Without a hardware IOMMU this results in the
282 * same device addresses being put into the dma-debug
283 * hash multiple times too. This can result in false
284 * positives being reported. Therefore we implement a
285 * best-fit algorithm here which returns the entry from
286 * the hash which fits best to the reference value
287 * instead of the first-fit.
288 */
289 matches += 1;
290 match_lvl = 0;
291 entry->size == ref->size ? ++match_lvl : 0;
292 entry->type == ref->type ? ++match_lvl : 0;
293 entry->direction == ref->direction ? ++match_lvl : 0;
294 entry->sg_call_ents == ref->sg_call_ents ? ++match_lvl : 0;
295
296 if (match_lvl == 4) {
297 /* perfect-fit - return the result */
298 return entry;
299 } else if (match_lvl > last_lvl) {
300 /*
301 * We found an entry that fits better then the
302 * previous one
303 */
304 last_lvl = match_lvl;
305 ret = entry;
306 }
307 }
308
309 /*
310 * If we have multiple matches but no perfect-fit, just return
311 * NULL.
312 */
313 ret = (matches == 1) ? ret : NULL;
314
315 return ret;
316}
317
318static struct dma_debug_entry *bucket_find_exact(struct hash_bucket *bucket,
319 struct dma_debug_entry *ref)
320{
321 return __hash_bucket_find(bucket, ref, exact_match);
322}
323
324static struct dma_debug_entry *bucket_find_contain(struct hash_bucket **bucket,
325 struct dma_debug_entry *ref,
326 unsigned long *flags)
327{
328
329 unsigned int max_range = dma_get_max_seg_size(ref->dev);
330 struct dma_debug_entry *entry, index = *ref;
331 unsigned int range = 0;
332
333 while (range <= max_range) {
334 entry = __hash_bucket_find(*bucket, &index, containing_match);
335
336 if (entry)
337 return entry;
338
339 /*
340 * Nothing found, go back a hash bucket
341 */
342 put_hash_bucket(*bucket, flags);
343 range += (1 << HASH_FN_SHIFT);
344 index.dev_addr -= (1 << HASH_FN_SHIFT);
345 *bucket = get_hash_bucket(&index, flags);
346 }
347
348 return NULL;
349}
350
351/*
352 * Add an entry to a hash bucket
353 */
354static void hash_bucket_add(struct hash_bucket *bucket,
355 struct dma_debug_entry *entry)
356{
357 list_add_tail(&entry->list, &bucket->list);
358}
359
360/*
361 * Remove entry from a hash bucket list
362 */
363static void hash_bucket_del(struct dma_debug_entry *entry)
364{
365 list_del(&entry->list);
366}
367
368/*
369 * Dump mapping entries for debugging purposes
370 */
371void debug_dma_dump_mappings(struct device *dev)
372{
373 int idx;
374
375 for (idx = 0; idx < HASH_SIZE; idx++) {
376 struct hash_bucket *bucket = &dma_entry_hash[idx];
377 struct dma_debug_entry *entry;
378 unsigned long flags;
379
380 spin_lock_irqsave(&bucket->lock, flags);
381
382 list_for_each_entry(entry, &bucket->list, list) {
383 if (!dev || dev == entry->dev) {
384 dev_info(entry->dev,
385 "%s idx %d P=%Lx D=%Lx L=%Lx %s\n",
386 type2name[entry->type], idx,
387 (unsigned long long)entry->paddr,
388 entry->dev_addr, entry->size,
389 dir2name[entry->direction]);
390 }
391 }
392
393 spin_unlock_irqrestore(&bucket->lock, flags);
394 }
395}
396EXPORT_SYMBOL(debug_dma_dump_mappings);
397
398/*
399 * Wrapper function for adding an entry to the hash.
400 * This function takes care of locking itself.
401 */
402static void add_dma_entry(struct dma_debug_entry *entry)
403{
404 struct hash_bucket *bucket;
405 unsigned long flags;
406
407 bucket = get_hash_bucket(entry, &flags);
408 hash_bucket_add(bucket, entry);
409 put_hash_bucket(bucket, &flags);
410}
411
412static struct dma_debug_entry *__dma_entry_alloc(void)
413{
414 struct dma_debug_entry *entry;
415
416 entry = list_entry(free_entries.next, struct dma_debug_entry, list);
417 list_del(&entry->list);
418 memset(entry, 0, sizeof(*entry));
419
420 num_free_entries -= 1;
421 if (num_free_entries < min_free_entries)
422 min_free_entries = num_free_entries;
423
424 return entry;
425}
426
427/* struct dma_entry allocator
428 *
429 * The next two functions implement the allocator for
430 * struct dma_debug_entries.
431 */
432static struct dma_debug_entry *dma_entry_alloc(void)
433{
434 struct dma_debug_entry *entry = NULL;
435 unsigned long flags;
436
437 spin_lock_irqsave(&free_entries_lock, flags);
438
439 if (list_empty(&free_entries)) {
440 pr_err("DMA-API: debugging out of memory - disabling\n");
441 global_disable = true;
442 goto out;
443 }
444
445 entry = __dma_entry_alloc();
446
447#ifdef CONFIG_STACKTRACE
448 entry->stacktrace.max_entries = DMA_DEBUG_STACKTRACE_ENTRIES;
449 entry->stacktrace.entries = entry->st_entries;
450 entry->stacktrace.skip = 2;
451 save_stack_trace(&entry->stacktrace);
452#endif
453
454out:
455 spin_unlock_irqrestore(&free_entries_lock, flags);
456
457 return entry;
458}
459
460static void dma_entry_free(struct dma_debug_entry *entry)
461{
462 unsigned long flags;
463
464 /*
465 * add to beginning of the list - this way the entries are
466 * more likely cache hot when they are reallocated.
467 */
468 spin_lock_irqsave(&free_entries_lock, flags);
469 list_add(&entry->list, &free_entries);
470 num_free_entries += 1;
471 spin_unlock_irqrestore(&free_entries_lock, flags);
472}
473
474int dma_debug_resize_entries(u32 num_entries)
475{
476 int i, delta, ret = 0;
477 unsigned long flags;
478 struct dma_debug_entry *entry;
479 LIST_HEAD(tmp);
480
481 spin_lock_irqsave(&free_entries_lock, flags);
482
483 if (nr_total_entries < num_entries) {
484 delta = num_entries - nr_total_entries;
485
486 spin_unlock_irqrestore(&free_entries_lock, flags);
487
488 for (i = 0; i < delta; i++) {
489 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
490 if (!entry)
491 break;
492
493 list_add_tail(&entry->list, &tmp);
494 }
495
496 spin_lock_irqsave(&free_entries_lock, flags);
497
498 list_splice(&tmp, &free_entries);
499 nr_total_entries += i;
500 num_free_entries += i;
501 } else {
502 delta = nr_total_entries - num_entries;
503
504 for (i = 0; i < delta && !list_empty(&free_entries); i++) {
505 entry = __dma_entry_alloc();
506 kfree(entry);
507 }
508
509 nr_total_entries -= i;
510 }
511
512 if (nr_total_entries != num_entries)
513 ret = 1;
514
515 spin_unlock_irqrestore(&free_entries_lock, flags);
516
517 return ret;
518}
519EXPORT_SYMBOL(dma_debug_resize_entries);
520
521/*
522 * DMA-API debugging init code
523 *
524 * The init code does two things:
525 * 1. Initialize core data structures
526 * 2. Preallocate a given number of dma_debug_entry structs
527 */
528
529static int prealloc_memory(u32 num_entries)
530{
531 struct dma_debug_entry *entry, *next_entry;
532 int i;
533
534 for (i = 0; i < num_entries; ++i) {
535 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
536 if (!entry)
537 goto out_err;
538
539 list_add_tail(&entry->list, &free_entries);
540 }
541
542 num_free_entries = num_entries;
543 min_free_entries = num_entries;
544
545 pr_info("DMA-API: preallocated %d debug entries\n", num_entries);
546
547 return 0;
548
549out_err:
550
551 list_for_each_entry_safe(entry, next_entry, &free_entries, list) {
552 list_del(&entry->list);
553 kfree(entry);
554 }
555
556 return -ENOMEM;
557}
558
559static ssize_t filter_read(struct file *file, char __user *user_buf,
560 size_t count, loff_t *ppos)
561{
562 char buf[NAME_MAX_LEN + 1];
563 unsigned long flags;
564 int len;
565
566 if (!current_driver_name[0])
567 return 0;
568
569 /*
570 * We can't copy to userspace directly because current_driver_name can
571 * only be read under the driver_name_lock with irqs disabled. So
572 * create a temporary copy first.
573 */
574 read_lock_irqsave(&driver_name_lock, flags);
575 len = scnprintf(buf, NAME_MAX_LEN + 1, "%s\n", current_driver_name);
576 read_unlock_irqrestore(&driver_name_lock, flags);
577
578 return simple_read_from_buffer(user_buf, count, ppos, buf, len);
579}
580
581static ssize_t filter_write(struct file *file, const char __user *userbuf,
582 size_t count, loff_t *ppos)
583{
584 char buf[NAME_MAX_LEN];
585 unsigned long flags;
586 size_t len;
587 int i;
588
589 /*
590 * We can't copy from userspace directly. Access to
591 * current_driver_name is protected with a write_lock with irqs
592 * disabled. Since copy_from_user can fault and may sleep we
593 * need to copy to temporary buffer first
594 */
595 len = min(count, (size_t)(NAME_MAX_LEN - 1));
596 if (copy_from_user(buf, userbuf, len))
597 return -EFAULT;
598
599 buf[len] = 0;
600
601 write_lock_irqsave(&driver_name_lock, flags);
602
603 /*
604 * Now handle the string we got from userspace very carefully.
605 * The rules are:
606 * - only use the first token we got
607 * - token delimiter is everything looking like a space
608 * character (' ', '\n', '\t' ...)
609 *
610 */
611 if (!isalnum(buf[0])) {
612 /*
613 * If the first character userspace gave us is not
614 * alphanumerical then assume the filter should be
615 * switched off.
616 */
617 if (current_driver_name[0])
618 pr_info("DMA-API: switching off dma-debug driver filter\n");
619 current_driver_name[0] = 0;
620 current_driver = NULL;
621 goto out_unlock;
622 }
623
624 /*
625 * Now parse out the first token and use it as the name for the
626 * driver to filter for.
627 */
628 for (i = 0; i < NAME_MAX_LEN - 1; ++i) {
629 current_driver_name[i] = buf[i];
630 if (isspace(buf[i]) || buf[i] == ' ' || buf[i] == 0)
631 break;
632 }
633 current_driver_name[i] = 0;
634 current_driver = NULL;
635
636 pr_info("DMA-API: enable driver filter for driver [%s]\n",
637 current_driver_name);
638
639out_unlock:
640 write_unlock_irqrestore(&driver_name_lock, flags);
641
642 return count;
643}
644
645static const struct file_operations filter_fops = {
646 .read = filter_read,
647 .write = filter_write,
648 .llseek = default_llseek,
649};
650
651static int dma_debug_fs_init(void)
652{
653 dma_debug_dent = debugfs_create_dir("dma-api", NULL);
654 if (!dma_debug_dent) {
655 pr_err("DMA-API: can not create debugfs directory\n");
656 return -ENOMEM;
657 }
658
659 global_disable_dent = debugfs_create_bool("disabled", 0444,
660 dma_debug_dent,
661 (u32 *)&global_disable);
662 if (!global_disable_dent)
663 goto out_err;
664
665 error_count_dent = debugfs_create_u32("error_count", 0444,
666 dma_debug_dent, &error_count);
667 if (!error_count_dent)
668 goto out_err;
669
670 show_all_errors_dent = debugfs_create_u32("all_errors", 0644,
671 dma_debug_dent,
672 &show_all_errors);
673 if (!show_all_errors_dent)
674 goto out_err;
675
676 show_num_errors_dent = debugfs_create_u32("num_errors", 0644,
677 dma_debug_dent,
678 &show_num_errors);
679 if (!show_num_errors_dent)
680 goto out_err;
681
682 num_free_entries_dent = debugfs_create_u32("num_free_entries", 0444,
683 dma_debug_dent,
684 &num_free_entries);
685 if (!num_free_entries_dent)
686 goto out_err;
687
688 min_free_entries_dent = debugfs_create_u32("min_free_entries", 0444,
689 dma_debug_dent,
690 &min_free_entries);
691 if (!min_free_entries_dent)
692 goto out_err;
693
694 filter_dent = debugfs_create_file("driver_filter", 0644,
695 dma_debug_dent, NULL, &filter_fops);
696 if (!filter_dent)
697 goto out_err;
698
699 return 0;
700
701out_err:
702 debugfs_remove_recursive(dma_debug_dent);
703
704 return -ENOMEM;
705}
706
707static int device_dma_allocations(struct device *dev, struct dma_debug_entry **out_entry)
708{
709 struct dma_debug_entry *entry;
710 unsigned long flags;
711 int count = 0, i;
712
713 local_irq_save(flags);
714
715 for (i = 0; i < HASH_SIZE; ++i) {
716 spin_lock(&dma_entry_hash[i].lock);
717 list_for_each_entry(entry, &dma_entry_hash[i].list, list) {
718 if (entry->dev == dev) {
719 count += 1;
720 *out_entry = entry;
721 }
722 }
723 spin_unlock(&dma_entry_hash[i].lock);
724 }
725
726 local_irq_restore(flags);
727
728 return count;
729}
730
731static int dma_debug_device_change(struct notifier_block *nb, unsigned long action, void *data)
732{
733 struct device *dev = data;
734 struct dma_debug_entry *uninitialized_var(entry);
735 int count;
736
737 if (global_disable)
738 return 0;
739
740 switch (action) {
741 case BUS_NOTIFY_UNBOUND_DRIVER:
742 count = device_dma_allocations(dev, &entry);
743 if (count == 0)
744 break;
745 err_printk(dev, entry, "DMA-API: device driver has pending "
746 "DMA allocations while released from device "
747 "[count=%d]\n"
748 "One of leaked entries details: "
749 "[device address=0x%016llx] [size=%llu bytes] "
750 "[mapped with %s] [mapped as %s]\n",
751 count, entry->dev_addr, entry->size,
752 dir2name[entry->direction], type2name[entry->type]);
753 break;
754 default:
755 break;
756 }
757
758 return 0;
759}
760
761void dma_debug_add_bus(struct bus_type *bus)
762{
763 struct notifier_block *nb;
764
765 if (global_disable)
766 return;
767
768 nb = kzalloc(sizeof(struct notifier_block), GFP_KERNEL);
769 if (nb == NULL) {
770 pr_err("dma_debug_add_bus: out of memory\n");
771 return;
772 }
773
774 nb->notifier_call = dma_debug_device_change;
775
776 bus_register_notifier(bus, nb);
777}
778
779/*
780 * Let the architectures decide how many entries should be preallocated.
781 */
782void dma_debug_init(u32 num_entries)
783{
784 int i;
785
786 if (global_disable)
787 return;
788
789 for (i = 0; i < HASH_SIZE; ++i) {
790 INIT_LIST_HEAD(&dma_entry_hash[i].list);
791 spin_lock_init(&dma_entry_hash[i].lock);
792 }
793
794 if (dma_debug_fs_init() != 0) {
795 pr_err("DMA-API: error creating debugfs entries - disabling\n");
796 global_disable = true;
797
798 return;
799 }
800
801 if (req_entries)
802 num_entries = req_entries;
803
804 if (prealloc_memory(num_entries) != 0) {
805 pr_err("DMA-API: debugging out of memory error - disabled\n");
806 global_disable = true;
807
808 return;
809 }
810
811 nr_total_entries = num_free_entries;
812
813 pr_info("DMA-API: debugging enabled by kernel config\n");
814}
815
816static __init int dma_debug_cmdline(char *str)
817{
818 if (!str)
819 return -EINVAL;
820
821 if (strncmp(str, "off", 3) == 0) {
822 pr_info("DMA-API: debugging disabled on kernel command line\n");
823 global_disable = true;
824 }
825
826 return 0;
827}
828
829static __init int dma_debug_entries_cmdline(char *str)
830{
831 int res;
832
833 if (!str)
834 return -EINVAL;
835
836 res = get_option(&str, &req_entries);
837
838 if (!res)
839 req_entries = 0;
840
841 return 0;
842}
843
844__setup("dma_debug=", dma_debug_cmdline);
845__setup("dma_debug_entries=", dma_debug_entries_cmdline);
846
847static void check_unmap(struct dma_debug_entry *ref)
848{
849 struct dma_debug_entry *entry;
850 struct hash_bucket *bucket;
851 unsigned long flags;
852
853 if (dma_mapping_error(ref->dev, ref->dev_addr)) {
854 err_printk(ref->dev, NULL, "DMA-API: device driver tries "
855 "to free an invalid DMA memory address\n");
856 return;
857 }
858
859 bucket = get_hash_bucket(ref, &flags);
860 entry = bucket_find_exact(bucket, ref);
861
862 if (!entry) {
863 err_printk(ref->dev, NULL, "DMA-API: device driver tries "
864 "to free DMA memory it has not allocated "
865 "[device address=0x%016llx] [size=%llu bytes]\n",
866 ref->dev_addr, ref->size);
867 goto out;
868 }
869
870 if (ref->size != entry->size) {
871 err_printk(ref->dev, entry, "DMA-API: device driver frees "
872 "DMA memory with different size "
873 "[device address=0x%016llx] [map size=%llu bytes] "
874 "[unmap size=%llu bytes]\n",
875 ref->dev_addr, entry->size, ref->size);
876 }
877
878 if (ref->type != entry->type) {
879 err_printk(ref->dev, entry, "DMA-API: device driver frees "
880 "DMA memory with wrong function "
881 "[device address=0x%016llx] [size=%llu bytes] "
882 "[mapped as %s] [unmapped as %s]\n",
883 ref->dev_addr, ref->size,
884 type2name[entry->type], type2name[ref->type]);
885 } else if ((entry->type == dma_debug_coherent) &&
886 (ref->paddr != entry->paddr)) {
887 err_printk(ref->dev, entry, "DMA-API: device driver frees "
888 "DMA memory with different CPU address "
889 "[device address=0x%016llx] [size=%llu bytes] "
890 "[cpu alloc address=0x%016llx] "
891 "[cpu free address=0x%016llx]",
892 ref->dev_addr, ref->size,
893 (unsigned long long)entry->paddr,
894 (unsigned long long)ref->paddr);
895 }
896
897 if (ref->sg_call_ents && ref->type == dma_debug_sg &&
898 ref->sg_call_ents != entry->sg_call_ents) {
899 err_printk(ref->dev, entry, "DMA-API: device driver frees "
900 "DMA sg list with different entry count "
901 "[map count=%d] [unmap count=%d]\n",
902 entry->sg_call_ents, ref->sg_call_ents);
903 }
904
905 /*
906 * This may be no bug in reality - but most implementations of the
907 * DMA API don't handle this properly, so check for it here
908 */
909 if (ref->direction != entry->direction) {
910 err_printk(ref->dev, entry, "DMA-API: device driver frees "
911 "DMA memory with different direction "
912 "[device address=0x%016llx] [size=%llu bytes] "
913 "[mapped with %s] [unmapped with %s]\n",
914 ref->dev_addr, ref->size,
915 dir2name[entry->direction],
916 dir2name[ref->direction]);
917 }
918
919 hash_bucket_del(entry);
920 dma_entry_free(entry);
921
922out:
923 put_hash_bucket(bucket, &flags);
924}
925
926static void check_for_stack(struct device *dev, void *addr)
927{
928 if (object_is_on_stack(addr))
929 err_printk(dev, NULL, "DMA-API: device driver maps memory from"
930 "stack [addr=%p]\n", addr);
931}
932
933static inline bool overlap(void *addr, unsigned long len, void *start, void *end)
934{
935 unsigned long a1 = (unsigned long)addr;
936 unsigned long b1 = a1 + len;
937 unsigned long a2 = (unsigned long)start;
938 unsigned long b2 = (unsigned long)end;
939
940 return !(b1 <= a2 || a1 >= b2);
941}
942
943static void check_for_illegal_area(struct device *dev, void *addr, unsigned long len)
944{
945 if (overlap(addr, len, _text, _etext) ||
946 overlap(addr, len, __start_rodata, __end_rodata))
947 err_printk(dev, NULL, "DMA-API: device driver maps memory from kernel text or rodata [addr=%p] [len=%lu]\n", addr, len);
948}
949
950static void check_sync(struct device *dev,
951 struct dma_debug_entry *ref,
952 bool to_cpu)
953{
954 struct dma_debug_entry *entry;
955 struct hash_bucket *bucket;
956 unsigned long flags;
957
958 bucket = get_hash_bucket(ref, &flags);
959
960 entry = bucket_find_contain(&bucket, ref, &flags);
961
962 if (!entry) {
963 err_printk(dev, NULL, "DMA-API: device driver tries "
964 "to sync DMA memory it has not allocated "
965 "[device address=0x%016llx] [size=%llu bytes]\n",
966 (unsigned long long)ref->dev_addr, ref->size);
967 goto out;
968 }
969
970 if (ref->size > entry->size) {
971 err_printk(dev, entry, "DMA-API: device driver syncs"
972 " DMA memory outside allocated range "
973 "[device address=0x%016llx] "
974 "[allocation size=%llu bytes] "
975 "[sync offset+size=%llu]\n",
976 entry->dev_addr, entry->size,
977 ref->size);
978 }
979
980 if (entry->direction == DMA_BIDIRECTIONAL)
981 goto out;
982
983 if (ref->direction != entry->direction) {
984 err_printk(dev, entry, "DMA-API: device driver syncs "
985 "DMA memory with different direction "
986 "[device address=0x%016llx] [size=%llu bytes] "
987 "[mapped with %s] [synced with %s]\n",
988 (unsigned long long)ref->dev_addr, entry->size,
989 dir2name[entry->direction],
990 dir2name[ref->direction]);
991 }
992
993 if (to_cpu && !(entry->direction == DMA_FROM_DEVICE) &&
994 !(ref->direction == DMA_TO_DEVICE))
995 err_printk(dev, entry, "DMA-API: device driver syncs "
996 "device read-only DMA memory for cpu "
997 "[device address=0x%016llx] [size=%llu bytes] "
998 "[mapped with %s] [synced with %s]\n",
999 (unsigned long long)ref->dev_addr, entry->size,
1000 dir2name[entry->direction],
1001 dir2name[ref->direction]);
1002
1003 if (!to_cpu && !(entry->direction == DMA_TO_DEVICE) &&
1004 !(ref->direction == DMA_FROM_DEVICE))
1005 err_printk(dev, entry, "DMA-API: device driver syncs "
1006 "device write-only DMA memory to device "
1007 "[device address=0x%016llx] [size=%llu bytes] "
1008 "[mapped with %s] [synced with %s]\n",
1009 (unsigned long long)ref->dev_addr, entry->size,
1010 dir2name[entry->direction],
1011 dir2name[ref->direction]);
1012
1013out:
1014 put_hash_bucket(bucket, &flags);
1015}
1016
1017void debug_dma_map_page(struct device *dev, struct page *page, size_t offset,
1018 size_t size, int direction, dma_addr_t dma_addr,
1019 bool map_single)
1020{
1021 struct dma_debug_entry *entry;
1022
1023 if (unlikely(global_disable))
1024 return;
1025
1026 if (unlikely(dma_mapping_error(dev, dma_addr)))
1027 return;
1028
1029 entry = dma_entry_alloc();
1030 if (!entry)
1031 return;
1032
1033 entry->dev = dev;
1034 entry->type = dma_debug_page;
1035 entry->paddr = page_to_phys(page) + offset;
1036 entry->dev_addr = dma_addr;
1037 entry->size = size;
1038 entry->direction = direction;
1039
1040 if (map_single)
1041 entry->type = dma_debug_single;
1042
1043 if (!PageHighMem(page)) {
1044 void *addr = page_address(page) + offset;
1045
1046 check_for_stack(dev, addr);
1047 check_for_illegal_area(dev, addr, size);
1048 }
1049
1050 add_dma_entry(entry);
1051}
1052EXPORT_SYMBOL(debug_dma_map_page);
1053
1054void debug_dma_unmap_page(struct device *dev, dma_addr_t addr,
1055 size_t size, int direction, bool map_single)
1056{
1057 struct dma_debug_entry ref = {
1058 .type = dma_debug_page,
1059 .dev = dev,
1060 .dev_addr = addr,
1061 .size = size,
1062 .direction = direction,
1063 };
1064
1065 if (unlikely(global_disable))
1066 return;
1067
1068 if (map_single)
1069 ref.type = dma_debug_single;
1070
1071 check_unmap(&ref);
1072}
1073EXPORT_SYMBOL(debug_dma_unmap_page);
1074
1075void debug_dma_map_sg(struct device *dev, struct scatterlist *sg,
1076 int nents, int mapped_ents, int direction)
1077{
1078 struct dma_debug_entry *entry;
1079 struct scatterlist *s;
1080 int i;
1081
1082 if (unlikely(global_disable))
1083 return;
1084
1085 for_each_sg(sg, s, mapped_ents, i) {
1086 entry = dma_entry_alloc();
1087 if (!entry)
1088 return;
1089
1090 entry->type = dma_debug_sg;
1091 entry->dev = dev;
1092 entry->paddr = sg_phys(s);
1093 entry->size = sg_dma_len(s);
1094 entry->dev_addr = sg_dma_address(s);
1095 entry->direction = direction;
1096 entry->sg_call_ents = nents;
1097 entry->sg_mapped_ents = mapped_ents;
1098
1099 if (!PageHighMem(sg_page(s))) {
1100 check_for_stack(dev, sg_virt(s));
1101 check_for_illegal_area(dev, sg_virt(s), sg_dma_len(s));
1102 }
1103
1104 add_dma_entry(entry);
1105 }
1106}
1107EXPORT_SYMBOL(debug_dma_map_sg);
1108
1109static int get_nr_mapped_entries(struct device *dev,
1110 struct dma_debug_entry *ref)
1111{
1112 struct dma_debug_entry *entry;
1113 struct hash_bucket *bucket;
1114 unsigned long flags;
1115 int mapped_ents;
1116
1117 bucket = get_hash_bucket(ref, &flags);
1118 entry = bucket_find_exact(bucket, ref);
1119 mapped_ents = 0;
1120
1121 if (entry)
1122 mapped_ents = entry->sg_mapped_ents;
1123 put_hash_bucket(bucket, &flags);
1124
1125 return mapped_ents;
1126}
1127
1128void debug_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
1129 int nelems, int dir)
1130{
1131 struct scatterlist *s;
1132 int mapped_ents = 0, i;
1133
1134 if (unlikely(global_disable))
1135 return;
1136
1137 for_each_sg(sglist, s, nelems, i) {
1138
1139 struct dma_debug_entry ref = {
1140 .type = dma_debug_sg,
1141 .dev = dev,
1142 .paddr = sg_phys(s),
1143 .dev_addr = sg_dma_address(s),
1144 .size = sg_dma_len(s),
1145 .direction = dir,
1146 .sg_call_ents = nelems,
1147 };
1148
1149 if (mapped_ents && i >= mapped_ents)
1150 break;
1151
1152 if (!i)
1153 mapped_ents = get_nr_mapped_entries(dev, &ref);
1154
1155 check_unmap(&ref);
1156 }
1157}
1158EXPORT_SYMBOL(debug_dma_unmap_sg);
1159
1160void debug_dma_alloc_coherent(struct device *dev, size_t size,
1161 dma_addr_t dma_addr, void *virt)
1162{
1163 struct dma_debug_entry *entry;
1164
1165 if (unlikely(global_disable))
1166 return;
1167
1168 if (unlikely(virt == NULL))
1169 return;
1170
1171 entry = dma_entry_alloc();
1172 if (!entry)
1173 return;
1174
1175 entry->type = dma_debug_coherent;
1176 entry->dev = dev;
1177 entry->paddr = virt_to_phys(virt);
1178 entry->size = size;
1179 entry->dev_addr = dma_addr;
1180 entry->direction = DMA_BIDIRECTIONAL;
1181
1182 add_dma_entry(entry);
1183}
1184EXPORT_SYMBOL(debug_dma_alloc_coherent);
1185
1186void debug_dma_free_coherent(struct device *dev, size_t size,
1187 void *virt, dma_addr_t addr)
1188{
1189 struct dma_debug_entry ref = {
1190 .type = dma_debug_coherent,
1191 .dev = dev,
1192 .paddr = virt_to_phys(virt),
1193 .dev_addr = addr,
1194 .size = size,
1195 .direction = DMA_BIDIRECTIONAL,
1196 };
1197
1198 if (unlikely(global_disable))
1199 return;
1200
1201 check_unmap(&ref);
1202}
1203EXPORT_SYMBOL(debug_dma_free_coherent);
1204
1205void debug_dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_handle,
1206 size_t size, int direction)
1207{
1208 struct dma_debug_entry ref;
1209
1210 if (unlikely(global_disable))
1211 return;
1212
1213 ref.type = dma_debug_single;
1214 ref.dev = dev;
1215 ref.dev_addr = dma_handle;
1216 ref.size = size;
1217 ref.direction = direction;
1218 ref.sg_call_ents = 0;
1219
1220 check_sync(dev, &ref, true);
1221}
1222EXPORT_SYMBOL(debug_dma_sync_single_for_cpu);
1223
1224void debug_dma_sync_single_for_device(struct device *dev,
1225 dma_addr_t dma_handle, size_t size,
1226 int direction)
1227{
1228 struct dma_debug_entry ref;
1229
1230 if (unlikely(global_disable))
1231 return;
1232
1233 ref.type = dma_debug_single;
1234 ref.dev = dev;
1235 ref.dev_addr = dma_handle;
1236 ref.size = size;
1237 ref.direction = direction;
1238 ref.sg_call_ents = 0;
1239
1240 check_sync(dev, &ref, false);
1241}
1242EXPORT_SYMBOL(debug_dma_sync_single_for_device);
1243
1244void debug_dma_sync_single_range_for_cpu(struct device *dev,
1245 dma_addr_t dma_handle,
1246 unsigned long offset, size_t size,
1247 int direction)
1248{
1249 struct dma_debug_entry ref;
1250
1251 if (unlikely(global_disable))
1252 return;
1253
1254 ref.type = dma_debug_single;
1255 ref.dev = dev;
1256 ref.dev_addr = dma_handle;
1257 ref.size = offset + size;
1258 ref.direction = direction;
1259 ref.sg_call_ents = 0;
1260
1261 check_sync(dev, &ref, true);
1262}
1263EXPORT_SYMBOL(debug_dma_sync_single_range_for_cpu);
1264
1265void debug_dma_sync_single_range_for_device(struct device *dev,
1266 dma_addr_t dma_handle,
1267 unsigned long offset,
1268 size_t size, int direction)
1269{
1270 struct dma_debug_entry ref;
1271
1272 if (unlikely(global_disable))
1273 return;
1274
1275 ref.type = dma_debug_single;
1276 ref.dev = dev;
1277 ref.dev_addr = dma_handle;
1278 ref.size = offset + size;
1279 ref.direction = direction;
1280 ref.sg_call_ents = 0;
1281
1282 check_sync(dev, &ref, false);
1283}
1284EXPORT_SYMBOL(debug_dma_sync_single_range_for_device);
1285
1286void debug_dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
1287 int nelems, int direction)
1288{
1289 struct scatterlist *s;
1290 int mapped_ents = 0, i;
1291
1292 if (unlikely(global_disable))
1293 return;
1294
1295 for_each_sg(sg, s, nelems, i) {
1296
1297 struct dma_debug_entry ref = {
1298 .type = dma_debug_sg,
1299 .dev = dev,
1300 .paddr = sg_phys(s),
1301 .dev_addr = sg_dma_address(s),
1302 .size = sg_dma_len(s),
1303 .direction = direction,
1304 .sg_call_ents = nelems,
1305 };
1306
1307 if (!i)
1308 mapped_ents = get_nr_mapped_entries(dev, &ref);
1309
1310 if (i >= mapped_ents)
1311 break;
1312
1313 check_sync(dev, &ref, true);
1314 }
1315}
1316EXPORT_SYMBOL(debug_dma_sync_sg_for_cpu);
1317
1318void debug_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
1319 int nelems, int direction)
1320{
1321 struct scatterlist *s;
1322 int mapped_ents = 0, i;
1323
1324 if (unlikely(global_disable))
1325 return;
1326
1327 for_each_sg(sg, s, nelems, i) {
1328
1329 struct dma_debug_entry ref = {
1330 .type = dma_debug_sg,
1331 .dev = dev,
1332 .paddr = sg_phys(s),
1333 .dev_addr = sg_dma_address(s),
1334 .size = sg_dma_len(s),
1335 .direction = direction,
1336 .sg_call_ents = nelems,
1337 };
1338 if (!i)
1339 mapped_ents = get_nr_mapped_entries(dev, &ref);
1340
1341 if (i >= mapped_ents)
1342 break;
1343
1344 check_sync(dev, &ref, false);
1345 }
1346}
1347EXPORT_SYMBOL(debug_dma_sync_sg_for_device);
1348
1349static int __init dma_debug_driver_setup(char *str)
1350{
1351 int i;
1352
1353 for (i = 0; i < NAME_MAX_LEN - 1; ++i, ++str) {
1354 current_driver_name[i] = *str;
1355 if (*str == 0)
1356 break;
1357 }
1358
1359 if (current_driver_name[0])
1360 pr_info("DMA-API: enable driver filter for driver [%s]\n",
1361 current_driver_name);
1362
1363
1364 return 1;
1365}
1366__setup("dma_debug_driver=", dma_debug_driver_setup);