?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
Merge branch 'for-linus' of git://git.infradead.org/users/sameo/mfd-2.6
[linux-btrfs-devel.git] / lib / dma-debug.c
blobdb07bfd9298ea93d4ddcdf76a8a0c868b955371b
1 /*
2 * Copyright (C) 2008 Advanced Micro Devices, Inc.
3 *
4 * Author: Joerg Roedel <joerg.roedel@amd.com>
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 as published
8 * by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 */
19
20 #include <linux/scatterlist.h>
21 #include <linux/dma-mapping.h>
22 #include <linux/stacktrace.h>
23 #include <linux/dma-debug.h>
24 #include <linux/spinlock.h>
25 #include <linux/debugfs.h>
26 #include <linux/uaccess.h>
27 #include <linux/device.h>
28 #include <linux/types.h>
29 #include <linux/sched.h>
30 #include <linux/ctype.h>
31 #include <linux/list.h>
32 #include <linux/slab.h>
33
34 #include <asm/sections.h>
35
36 #define HASH_SIZE 1024ULL
37 #define HASH_FN_SHIFT 13
38 #define HASH_FN_MASK (HASH_SIZE - 1)
39
40 enum {
41 dma_debug_single,
42 dma_debug_page,
43 dma_debug_sg,
44 dma_debug_coherent,
45 };
46
47 #define DMA_DEBUG_STACKTRACE_ENTRIES 5
48
49 struct dma_debug_entry {
50 struct list_head list;
51 struct device *dev;
52 int type;
53 phys_addr_t paddr;
54 u64 dev_addr;
55 u64 size;
56 int direction;
57 int sg_call_ents;
58 int sg_mapped_ents;
59 #ifdef CONFIG_STACKTRACE
60 struct stack_trace stacktrace;
61 unsigned long st_entries[DMA_DEBUG_STACKTRACE_ENTRIES];
62 #endif
63 };
64
65 struct hash_bucket {
66 struct list_head list;
67 spinlock_t lock;
68 } ____cacheline_aligned_in_smp;
69
70 /* Hash list to save the allocated dma addresses */
71 static struct hash_bucket dma_entry_hash[HASH_SIZE];
72 /* List of pre-allocated dma_debug_entry's */
73 static LIST_HEAD(free_entries);
74 /* Lock for the list above */
75 static DEFINE_SPINLOCK(free_entries_lock);
76
77 /* Global disable flag - will be set in case of an error */
78 static bool global_disable __read_mostly;
79
80 /* Global error count */
81 static u32 error_count;
82
83 /* Global error show enable*/
84 static u32 show_all_errors __read_mostly;
85 /* Number of errors to show */
86 static u32 show_num_errors = 1;
87
88 static u32 num_free_entries;
89 static u32 min_free_entries;
90 static u32 nr_total_entries;
91
92 /* number of preallocated entries requested by kernel cmdline */
93 static u32 req_entries;
94
95 /* debugfs dentry's for the stuff above */
96 static struct dentry *dma_debug_dent __read_mostly;
97 static struct dentry *global_disable_dent __read_mostly;
98 static struct dentry *error_count_dent __read_mostly;
99 static struct dentry *show_all_errors_dent __read_mostly;
100 static struct dentry *show_num_errors_dent __read_mostly;
101 static struct dentry *num_free_entries_dent __read_mostly;
102 static struct dentry *min_free_entries_dent __read_mostly;
103 static struct dentry *filter_dent __read_mostly;
104
105 /* per-driver filter related state */
106
107 #define NAME_MAX_LEN 64
108
109 static char current_driver_name[NAME_MAX_LEN] __read_mostly;
110 static struct device_driver *current_driver __read_mostly;
111
112 static DEFINE_RWLOCK(driver_name_lock);
113
114 static const char *type2name[4] = { "single", "page",
115 "scather-gather", "coherent" };
116
117 static const char *dir2name[4] = { "DMA_BIDIRECTIONAL", "DMA_TO_DEVICE",
118 "DMA_FROM_DEVICE", "DMA_NONE" };
119
120 /* little merge helper - remove it after the merge window */
121 #ifndef BUS_NOTIFY_UNBOUND_DRIVER
122 #define BUS_NOTIFY_UNBOUND_DRIVER 0x0005
123 #endif
124
125 /*
126 * The access to some variables in this macro is racy. We can't use atomic_t
127 * here because all these variables are exported to debugfs. Some of them even
128 * writeable. This is also the reason why a lock won't help much. But anyway,
129 * the races are no big deal. Here is why:
130 *
131 * error_count: the addition is racy, but the worst thing that can happen is
132 * that we don't count some errors
133 * show_num_errors: the subtraction is racy. Also no big deal because in
134 * worst case this will result in one warning more in the
135 * system log than the user configured. This variable is
136 * writeable via debugfs.
137 */
138 static inline void dump_entry_trace(struct dma_debug_entry *entry)
139 {
140 #ifdef CONFIG_STACKTRACE
141 if (entry) {
142 pr_warning("Mapped at:\n");
143 print_stack_trace(&entry->stacktrace, 0);
144 }
145 #endif
146 }
147
148 static bool driver_filter(struct device *dev)
149 {
150 struct device_driver *drv;
151 unsigned long flags;
152 bool ret;
153
154 /* driver filter off */
155 if (likely(!current_driver_name[0]))
156 return true;
157
158 /* driver filter on and initialized */
159 if (current_driver && dev && dev->driver == current_driver)
160 return true;
161
162 /* driver filter on, but we can't filter on a NULL device... */
163 if (!dev)
164 return false;
165
166 if (current_driver || !current_driver_name[0])
167 return false;
168
169 /* driver filter on but not yet initialized */
170 drv = get_driver(dev->driver);
171 if (!drv)
172 return false;
173
174 /* lock to protect against change of current_driver_name */
175 read_lock_irqsave(&driver_name_lock, flags);
176
177 ret = false;
178 if (drv->name &&
179 strncmp(current_driver_name, drv->name, NAME_MAX_LEN - 1) == 0) {
180 current_driver = drv;
181 ret = true;
182 }
183
184 read_unlock_irqrestore(&driver_name_lock, flags);
185 put_driver(drv);
186
187 return ret;
188 }
189
190 #define err_printk(dev, entry, format, arg...) do { \
191 error_count += 1; \
192 if (driver_filter(dev) && \
193 (show_all_errors || show_num_errors > 0)) { \
194 WARN(1, "%s %s: " format, \
195 dev ? dev_driver_string(dev) : "NULL", \
196 dev ? dev_name(dev) : "NULL", ## arg); \
197 dump_entry_trace(entry); \
198 } \
199 if (!show_all_errors && show_num_errors > 0) \
200 show_num_errors -= 1; \
201 } while (0);
202
203 /*
204 * Hash related functions
205 *
206 * Every DMA-API request is saved into a struct dma_debug_entry. To
207 * have quick access to these structs they are stored into a hash.
208 */
209 static int hash_fn(struct dma_debug_entry *entry)
210 {
211 /*
212 * Hash function is based on the dma address.
213 * We use bits 20-27 here as the index into the hash
214 */
215 return (entry->dev_addr >> HASH_FN_SHIFT) & HASH_FN_MASK;
216 }
217
218 /*
219 * Request exclusive access to a hash bucket for a given dma_debug_entry.
220 */
221 static struct hash_bucket *get_hash_bucket(struct dma_debug_entry *entry,
222 unsigned long *flags)
223 {
224 int idx = hash_fn(entry);
225 unsigned long __flags;
226
227 spin_lock_irqsave(&dma_entry_hash[idx].lock, __flags);
228 *flags = __flags;
229 return &dma_entry_hash[idx];
230 }
231
232 /*
233 * Give up exclusive access to the hash bucket
234 */
235 static void put_hash_bucket(struct hash_bucket *bucket,
236 unsigned long *flags)
237 {
238 unsigned long __flags = *flags;
239
240 spin_unlock_irqrestore(&bucket->lock, __flags);
241 }
242
243 /*
244 * Search a given entry in the hash bucket list
245 */
246 static struct dma_debug_entry *hash_bucket_find(struct hash_bucket *bucket,
247 struct dma_debug_entry *ref)
248 {
249 struct dma_debug_entry *entry, *ret = NULL;
250 int matches = 0, match_lvl, last_lvl = 0;
251
252 list_for_each_entry(entry, &bucket->list, list) {
253 if ((entry->dev_addr != ref->dev_addr) ||
254 (entry->dev != ref->dev))
255 continue;
256
257 /*
258 * Some drivers map the same physical address multiple
259 * times. Without a hardware IOMMU this results in the
260 * same device addresses being put into the dma-debug
261 * hash multiple times too. This can result in false
262 * positives being reported. Therefore we implement a
263 * best-fit algorithm here which returns the entry from
264 * the hash which fits best to the reference value
265 * instead of the first-fit.
266 */
267 matches += 1;
268 match_lvl = 0;
269 entry->size == ref->size ? ++match_lvl : 0;
270 entry->type == ref->type ? ++match_lvl : 0;
271 entry->direction == ref->direction ? ++match_lvl : 0;
272 entry->sg_call_ents == ref->sg_call_ents ? ++match_lvl : 0;
273
274 if (match_lvl == 4) {
275 /* perfect-fit - return the result */
276 return entry;
277 } else if (match_lvl > last_lvl) {
278 /*
279 * We found an entry that fits better then the
280 * previous one
281 */
282 last_lvl = match_lvl;
283 ret = entry;
284 }
285 }
286
287 /*
288 * If we have multiple matches but no perfect-fit, just return
289 * NULL.
290 */
291 ret = (matches == 1) ? ret : NULL;
292
293 return ret;
294 }
295
296 /*
297 * Add an entry to a hash bucket
298 */
299 static void hash_bucket_add(struct hash_bucket *bucket,
300 struct dma_debug_entry *entry)
301 {
302 list_add_tail(&entry->list, &bucket->list);
303 }
304
305 /*
306 * Remove entry from a hash bucket list
307 */
308 static void hash_bucket_del(struct dma_debug_entry *entry)
309 {
310 list_del(&entry->list);
311 }
312
313 /*
314 * Dump mapping entries for debugging purposes
315 */
316 void debug_dma_dump_mappings(struct device *dev)
317 {
318 int idx;
319
320 for (idx = 0; idx < HASH_SIZE; idx++) {
321 struct hash_bucket *bucket = &dma_entry_hash[idx];
322 struct dma_debug_entry *entry;
323 unsigned long flags;
324
325 spin_lock_irqsave(&bucket->lock, flags);
326
327 list_for_each_entry(entry, &bucket->list, list) {
328 if (!dev || dev == entry->dev) {
329 dev_info(entry->dev,
330 "%s idx %d P=%Lx D=%Lx L=%Lx %s\n",
331 type2name[entry->type], idx,
332 (unsigned long long)entry->paddr,
333 entry->dev_addr, entry->size,
334 dir2name[entry->direction]);
335 }
336 }
337
338 spin_unlock_irqrestore(&bucket->lock, flags);
339 }
340 }
341 EXPORT_SYMBOL(debug_dma_dump_mappings);
342
343 /*
344 * Wrapper function for adding an entry to the hash.
345 * This function takes care of locking itself.
346 */
347 static void add_dma_entry(struct dma_debug_entry *entry)
348 {
349 struct hash_bucket *bucket;
350 unsigned long flags;
351
352 bucket = get_hash_bucket(entry, &flags);
353 hash_bucket_add(bucket, entry);
354 put_hash_bucket(bucket, &flags);
355 }
356
357 static struct dma_debug_entry *__dma_entry_alloc(void)
358 {
359 struct dma_debug_entry *entry;
360
361 entry = list_entry(free_entries.next, struct dma_debug_entry, list);
362 list_del(&entry->list);
363 memset(entry, 0, sizeof(*entry));
364
365 num_free_entries -= 1;
366 if (num_free_entries < min_free_entries)
367 min_free_entries = num_free_entries;
368
369 return entry;
370 }
371
372 /* struct dma_entry allocator
373 *
374 * The next two functions implement the allocator for
375 * struct dma_debug_entries.
376 */
377 static struct dma_debug_entry *dma_entry_alloc(void)
378 {
379 struct dma_debug_entry *entry = NULL;
380 unsigned long flags;
381
382 spin_lock_irqsave(&free_entries_lock, flags);
383
384 if (list_empty(&free_entries)) {
385 pr_err("DMA-API: debugging out of memory - disabling\n");
386 global_disable = true;
387 goto out;
388 }
389
390 entry = __dma_entry_alloc();
391
392 #ifdef CONFIG_STACKTRACE
393 entry->stacktrace.max_entries = DMA_DEBUG_STACKTRACE_ENTRIES;
394 entry->stacktrace.entries = entry->st_entries;
395 entry->stacktrace.skip = 2;
396 save_stack_trace(&entry->stacktrace);
397 #endif
398
399 out:
400 spin_unlock_irqrestore(&free_entries_lock, flags);
401
402 return entry;
403 }
404
405 static void dma_entry_free(struct dma_debug_entry *entry)
406 {
407 unsigned long flags;
408
409 /*
410 * add to beginning of the list - this way the entries are
411 * more likely cache hot when they are reallocated.
412 */
413 spin_lock_irqsave(&free_entries_lock, flags);
414 list_add(&entry->list, &free_entries);
415 num_free_entries += 1;
416 spin_unlock_irqrestore(&free_entries_lock, flags);
417 }
418
419 int dma_debug_resize_entries(u32 num_entries)
420 {
421 int i, delta, ret = 0;
422 unsigned long flags;
423 struct dma_debug_entry *entry;
424 LIST_HEAD(tmp);
425
426 spin_lock_irqsave(&free_entries_lock, flags);
427
428 if (nr_total_entries < num_entries) {
429 delta = num_entries - nr_total_entries;
430
431 spin_unlock_irqrestore(&free_entries_lock, flags);
432
433 for (i = 0; i < delta; i++) {
434 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
435 if (!entry)
436 break;
437
438 list_add_tail(&entry->list, &tmp);
439 }
440
441 spin_lock_irqsave(&free_entries_lock, flags);
442
443 list_splice(&tmp, &free_entries);
444 nr_total_entries += i;
445 num_free_entries += i;
446 } else {
447 delta = nr_total_entries - num_entries;
448
449 for (i = 0; i < delta && !list_empty(&free_entries); i++) {
450 entry = __dma_entry_alloc();
451 kfree(entry);
452 }
453
454 nr_total_entries -= i;
455 }
456
457 if (nr_total_entries != num_entries)
458 ret = 1;
459
460 spin_unlock_irqrestore(&free_entries_lock, flags);
461
462 return ret;
463 }
464 EXPORT_SYMBOL(dma_debug_resize_entries);
465
466 /*
467 * DMA-API debugging init code
468 *
469 * The init code does two things:
470 * 1. Initialize core data structures
471 * 2. Preallocate a given number of dma_debug_entry structs
472 */
473
474 static int prealloc_memory(u32 num_entries)
475 {
476 struct dma_debug_entry *entry, *next_entry;
477 int i;
478
479 for (i = 0; i < num_entries; ++i) {
480 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
481 if (!entry)
482 goto out_err;
483
484 list_add_tail(&entry->list, &free_entries);
485 }
486
487 num_free_entries = num_entries;
488 min_free_entries = num_entries;
489
490 pr_info("DMA-API: preallocated %d debug entries\n", num_entries);
491
492 return 0;
493
494 out_err:
495
496 list_for_each_entry_safe(entry, next_entry, &free_entries, list) {
497 list_del(&entry->list);
498 kfree(entry);
499 }
500
501 return -ENOMEM;
502 }
503
504 static ssize_t filter_read(struct file *file, char __user *user_buf,
505 size_t count, loff_t *ppos)
506 {
507 char buf[NAME_MAX_LEN + 1];
508 unsigned long flags;
509 int len;
510
511 if (!current_driver_name[0])
512 return 0;
513
514 /*
515 * We can't copy to userspace directly because current_driver_name can
516 * only be read under the driver_name_lock with irqs disabled. So
517 * create a temporary copy first.
518 */
519 read_lock_irqsave(&driver_name_lock, flags);
520 len = scnprintf(buf, NAME_MAX_LEN + 1, "%s\n", current_driver_name);
521 read_unlock_irqrestore(&driver_name_lock, flags);
522
523 return simple_read_from_buffer(user_buf, count, ppos, buf, len);
524 }
525
526 static ssize_t filter_write(struct file *file, const char __user *userbuf,
527 size_t count, loff_t *ppos)
528 {
529 char buf[NAME_MAX_LEN];
530 unsigned long flags;
531 size_t len;
532 int i;
533
534 /*
535 * We can't copy from userspace directly. Access to
536 * current_driver_name is protected with a write_lock with irqs
537 * disabled. Since copy_from_user can fault and may sleep we
538 * need to copy to temporary buffer first
539 */
540 len = min(count, (size_t)(NAME_MAX_LEN - 1));
541 if (copy_from_user(buf, userbuf, len))
542 return -EFAULT;
543
544 buf[len] = 0;
545
546 write_lock_irqsave(&driver_name_lock, flags);
547
548 /*
549 * Now handle the string we got from userspace very carefully.
550 * The rules are:
551 * - only use the first token we got
552 * - token delimiter is everything looking like a space
553 * character (' ', '\n', '\t' ...)
554 *
555 */
556 if (!isalnum(buf[0])) {
557 /*
558 * If the first character userspace gave us is not
559 * alphanumerical then assume the filter should be
560 * switched off.
561 */
562 if (current_driver_name[0])
563 pr_info("DMA-API: switching off dma-debug driver filter\n");
564 current_driver_name[0] = 0;
565 current_driver = NULL;
566 goto out_unlock;
567 }
568
569 /*
570 * Now parse out the first token and use it as the name for the
571 * driver to filter for.
572 */
573 for (i = 0; i < NAME_MAX_LEN - 1; ++i) {
574 current_driver_name[i] = buf[i];
575 if (isspace(buf[i]) || buf[i] == ' ' || buf[i] == 0)
576 break;
577 }
578 current_driver_name[i] = 0;
579 current_driver = NULL;
580
581 pr_info("DMA-API: enable driver filter for driver [%s]\n",
582 current_driver_name);
583
584 out_unlock:
585 write_unlock_irqrestore(&driver_name_lock, flags);
586
587 return count;
588 }
589
590 static const struct file_operations filter_fops = {
591 .read = filter_read,
592 .write = filter_write,
593 .llseek = default_llseek,
594 };
595
596 static int dma_debug_fs_init(void)
597 {
598 dma_debug_dent = debugfs_create_dir("dma-api", NULL);
599 if (!dma_debug_dent) {
600 pr_err("DMA-API: can not create debugfs directory\n");
601 return -ENOMEM;
602 }
603
604 global_disable_dent = debugfs_create_bool("disabled", 0444,
605 dma_debug_dent,
606 (u32 *)&global_disable);
607 if (!global_disable_dent)
608 goto out_err;
609
610 error_count_dent = debugfs_create_u32("error_count", 0444,
611 dma_debug_dent, &error_count);
612 if (!error_count_dent)
613 goto out_err;
614
615 show_all_errors_dent = debugfs_create_u32("all_errors", 0644,
616 dma_debug_dent,
617 &show_all_errors);
618 if (!show_all_errors_dent)
619 goto out_err;
620
621 show_num_errors_dent = debugfs_create_u32("num_errors", 0644,
622 dma_debug_dent,
623 &show_num_errors);
624 if (!show_num_errors_dent)
625 goto out_err;
626
627 num_free_entries_dent = debugfs_create_u32("num_free_entries", 0444,
628 dma_debug_dent,
629 &num_free_entries);
630 if (!num_free_entries_dent)
631 goto out_err;
632
633 min_free_entries_dent = debugfs_create_u32("min_free_entries", 0444,
634 dma_debug_dent,
635 &min_free_entries);
636 if (!min_free_entries_dent)
637 goto out_err;
638
639 filter_dent = debugfs_create_file("driver_filter", 0644,
640 dma_debug_dent, NULL, &filter_fops);
641 if (!filter_dent)
642 goto out_err;
643
644 return 0;
645
646 out_err:
647 debugfs_remove_recursive(dma_debug_dent);
648
649 return -ENOMEM;
650 }
651
652 static int device_dma_allocations(struct device *dev, struct dma_debug_entry **out_entry)
653 {
654 struct dma_debug_entry *entry;
655 unsigned long flags;
656 int count = 0, i;
657
658 local_irq_save(flags);
659
660 for (i = 0; i < HASH_SIZE; ++i) {
661 spin_lock(&dma_entry_hash[i].lock);
662 list_for_each_entry(entry, &dma_entry_hash[i].list, list) {
663 if (entry->dev == dev) {
664 count += 1;
665 *out_entry = entry;
666 }
667 }
668 spin_unlock(&dma_entry_hash[i].lock);
669 }
670
671 local_irq_restore(flags);
672
673 return count;
674 }
675
676 static int dma_debug_device_change(struct notifier_block *nb, unsigned long action, void *data)
677 {
678 struct device *dev = data;
679 struct dma_debug_entry *uninitialized_var(entry);
680 int count;
681
682 if (global_disable)
683 return 0;
684
685 switch (action) {
686 case BUS_NOTIFY_UNBOUND_DRIVER:
687 count = device_dma_allocations(dev, &entry);
688 if (count == 0)
689 break;
690 err_printk(dev, entry, "DMA-API: device driver has pending "
691 "DMA allocations while released from device "
692 "[count=%d]\n"
693 "One of leaked entries details: "
694 "[device address=0x%016llx] [size=%llu bytes] "
695 "[mapped with %s] [mapped as %s]\n",
696 count, entry->dev_addr, entry->size,
697 dir2name[entry->direction], type2name[entry->type]);
698 break;
699 default:
700 break;
701 }
702
703 return 0;
704 }
705
706 void dma_debug_add_bus(struct bus_type *bus)
707 {
708 struct notifier_block *nb;
709
710 if (global_disable)
711 return;
712
713 nb = kzalloc(sizeof(struct notifier_block), GFP_KERNEL);
714 if (nb == NULL) {
715 pr_err("dma_debug_add_bus: out of memory\n");
716 return;
717 }
718
719 nb->notifier_call = dma_debug_device_change;
720
721 bus_register_notifier(bus, nb);
722 }
723
724 /*
725 * Let the architectures decide how many entries should be preallocated.
726 */
727 void dma_debug_init(u32 num_entries)
728 {
729 int i;
730
731 if (global_disable)
732 return;
733
734 for (i = 0; i < HASH_SIZE; ++i) {
735 INIT_LIST_HEAD(&dma_entry_hash[i].list);
736 spin_lock_init(&dma_entry_hash[i].lock);
737 }
738
739 if (dma_debug_fs_init() != 0) {
740 pr_err("DMA-API: error creating debugfs entries - disabling\n");
741 global_disable = true;
742
743 return;
744 }
745
746 if (req_entries)
747 num_entries = req_entries;
748
749 if (prealloc_memory(num_entries) != 0) {
750 pr_err("DMA-API: debugging out of memory error - disabled\n");
751 global_disable = true;
752
753 return;
754 }
755
756 nr_total_entries = num_free_entries;
757
758 pr_info("DMA-API: debugging enabled by kernel config\n");
759 }
760
761 static __init int dma_debug_cmdline(char *str)
762 {
763 if (!str)
764 return -EINVAL;
765
766 if (strncmp(str, "off", 3) == 0) {
767 pr_info("DMA-API: debugging disabled on kernel command line\n");
768 global_disable = true;
769 }
770
771 return 0;
772 }
773
774 static __init int dma_debug_entries_cmdline(char *str)
775 {
776 int res;
777
778 if (!str)
779 return -EINVAL;
780
781 res = get_option(&str, &req_entries);
782
783 if (!res)
784 req_entries = 0;
785
786 return 0;
787 }
788
789 __setup("dma_debug=", dma_debug_cmdline);
790 __setup("dma_debug_entries=", dma_debug_entries_cmdline);
791
792 static void check_unmap(struct dma_debug_entry *ref)
793 {
794 struct dma_debug_entry *entry;
795 struct hash_bucket *bucket;
796 unsigned long flags;
797
798 if (dma_mapping_error(ref->dev, ref->dev_addr)) {
799 err_printk(ref->dev, NULL, "DMA-API: device driver tries "
800 "to free an invalid DMA memory address\n");
801 return;
802 }
803
804 bucket = get_hash_bucket(ref, &flags);
805 entry = hash_bucket_find(bucket, ref);
806
807 if (!entry) {
808 err_printk(ref->dev, NULL, "DMA-API: device driver tries "
809 "to free DMA memory it has not allocated "
810 "[device address=0x%016llx] [size=%llu bytes]\n",
811 ref->dev_addr, ref->size);
812 goto out;
813 }
814
815 if (ref->size != entry->size) {
816 err_printk(ref->dev, entry, "DMA-API: device driver frees "
817 "DMA memory with different size "
818 "[device address=0x%016llx] [map size=%llu bytes] "
819 "[unmap size=%llu bytes]\n",
820 ref->dev_addr, entry->size, ref->size);
821 }
822
823 if (ref->type != entry->type) {
824 err_printk(ref->dev, entry, "DMA-API: device driver frees "
825 "DMA memory with wrong function "
826 "[device address=0x%016llx] [size=%llu bytes] "
827 "[mapped as %s] [unmapped as %s]\n",
828 ref->dev_addr, ref->size,
829 type2name[entry->type], type2name[ref->type]);
830 } else if ((entry->type == dma_debug_coherent) &&
831 (ref->paddr != entry->paddr)) {
832 err_printk(ref->dev, entry, "DMA-API: device driver frees "
833 "DMA memory with different CPU address "
834 "[device address=0x%016llx] [size=%llu bytes] "
835 "[cpu alloc address=0x%016llx] "
836 "[cpu free address=0x%016llx]",
837 ref->dev_addr, ref->size,
838 (unsigned long long)entry->paddr,
839 (unsigned long long)ref->paddr);
840 }
841
842 if (ref->sg_call_ents && ref->type == dma_debug_sg &&
843 ref->sg_call_ents != entry->sg_call_ents) {
844 err_printk(ref->dev, entry, "DMA-API: device driver frees "
845 "DMA sg list with different entry count "
846 "[map count=%d] [unmap count=%d]\n",
847 entry->sg_call_ents, ref->sg_call_ents);
848 }
849
850 /*
851 * This may be no bug in reality - but most implementations of the
852 * DMA API don't handle this properly, so check for it here
853 */
854 if (ref->direction != entry->direction) {
855 err_printk(ref->dev, entry, "DMA-API: device driver frees "
856 "DMA memory with different direction "
857 "[device address=0x%016llx] [size=%llu bytes] "
858 "[mapped with %s] [unmapped with %s]\n",
859 ref->dev_addr, ref->size,
860 dir2name[entry->direction],
861 dir2name[ref->direction]);
862 }
863
864 hash_bucket_del(entry);
865 dma_entry_free(entry);
866
867 out:
868 put_hash_bucket(bucket, &flags);
869 }
870
871 static void check_for_stack(struct device *dev, void *addr)
872 {
873 if (object_is_on_stack(addr))
874 err_printk(dev, NULL, "DMA-API: device driver maps memory from"
875 "stack [addr=%p]\n", addr);
876 }
877
878 static inline bool overlap(void *addr, unsigned long len, void *start, void *end)
879 {
880 unsigned long a1 = (unsigned long)addr;
881 unsigned long b1 = a1 + len;
882 unsigned long a2 = (unsigned long)start;
883 unsigned long b2 = (unsigned long)end;
884
885 return !(b1 <= a2 || a1 >= b2);
886 }
887
888 static void check_for_illegal_area(struct device *dev, void *addr, unsigned long len)
889 {
890 if (overlap(addr, len, _text, _etext) ||
891 overlap(addr, len, __start_rodata, __end_rodata))
892 err_printk(dev, NULL, "DMA-API: device driver maps memory from kernel text or rodata [addr=%p] [len=%lu]\n", addr, len);
893 }
894
895 static void check_sync(struct device *dev,
896 struct dma_debug_entry *ref,
897 bool to_cpu)
898 {
899 struct dma_debug_entry *entry;
900 struct hash_bucket *bucket;
901 unsigned long flags;
902
903 bucket = get_hash_bucket(ref, &flags);
904
905 entry = hash_bucket_find(bucket, ref);
906
907 if (!entry) {
908 err_printk(dev, NULL, "DMA-API: device driver tries "
909 "to sync DMA memory it has not allocated "
910 "[device address=0x%016llx] [size=%llu bytes]\n",
911 (unsigned long long)ref->dev_addr, ref->size);
912 goto out;
913 }
914
915 if (ref->size > entry->size) {
916 err_printk(dev, entry, "DMA-API: device driver syncs"
917 " DMA memory outside allocated range "
918 "[device address=0x%016llx] "
919 "[allocation size=%llu bytes] "
920 "[sync offset+size=%llu]\n",
921 entry->dev_addr, entry->size,
922 ref->size);
923 }
924
925 if (entry->direction == DMA_BIDIRECTIONAL)
926 goto out;
927
928 if (ref->direction != entry->direction) {
929 err_printk(dev, entry, "DMA-API: device driver syncs "
930 "DMA memory with different direction "
931 "[device address=0x%016llx] [size=%llu bytes] "
932 "[mapped with %s] [synced with %s]\n",
933 (unsigned long long)ref->dev_addr, entry->size,
934 dir2name[entry->direction],
935 dir2name[ref->direction]);
936 }
937
938 if (to_cpu && !(entry->direction == DMA_FROM_DEVICE) &&
939 !(ref->direction == DMA_TO_DEVICE))
940 err_printk(dev, entry, "DMA-API: device driver syncs "
941 "device read-only DMA memory for cpu "
942 "[device address=0x%016llx] [size=%llu bytes] "
943 "[mapped with %s] [synced with %s]\n",
944 (unsigned long long)ref->dev_addr, entry->size,
945 dir2name[entry->direction],
946 dir2name[ref->direction]);
947
948 if (!to_cpu && !(entry->direction == DMA_TO_DEVICE) &&
949 !(ref->direction == DMA_FROM_DEVICE))
950 err_printk(dev, entry, "DMA-API: device driver syncs "
951 "device write-only DMA memory to device "
952 "[device address=0x%016llx] [size=%llu bytes] "
953 "[mapped with %s] [synced with %s]\n",
954 (unsigned long long)ref->dev_addr, entry->size,
955 dir2name[entry->direction],
956 dir2name[ref->direction]);
957
958 out:
959 put_hash_bucket(bucket, &flags);
960 }
961
962 void debug_dma_map_page(struct device *dev, struct page *page, size_t offset,
963 size_t size, int direction, dma_addr_t dma_addr,
964 bool map_single)
965 {
966 struct dma_debug_entry *entry;
967
968 if (unlikely(global_disable))
969 return;
970
971 if (unlikely(dma_mapping_error(dev, dma_addr)))
972 return;
973
974 entry = dma_entry_alloc();
975 if (!entry)
976 return;
977
978 entry->dev = dev;
979 entry->type = dma_debug_page;
980 entry->paddr = page_to_phys(page) + offset;
981 entry->dev_addr = dma_addr;
982 entry->size = size;
983 entry->direction = direction;
984
985 if (map_single)
986 entry->type = dma_debug_single;
987
988 if (!PageHighMem(page)) {
989 void *addr = page_address(page) + offset;
990
991 check_for_stack(dev, addr);
992 check_for_illegal_area(dev, addr, size);
993 }
994
995 add_dma_entry(entry);
996 }
997 EXPORT_SYMBOL(debug_dma_map_page);
998
999 void debug_dma_unmap_page(struct device *dev, dma_addr_t addr,
1000 size_t size, int direction, bool map_single)
1001 {
1002 struct dma_debug_entry ref = {
1003 .type = dma_debug_page,
1004 .dev = dev,
1005 .dev_addr = addr,
1006 .size = size,
1007 .direction = direction,
1008 };
1009
1010 if (unlikely(global_disable))
1011 return;
1012
1013 if (map_single)
1014 ref.type = dma_debug_single;
1015
1016 check_unmap(&ref);
1017 }
1018 EXPORT_SYMBOL(debug_dma_unmap_page);
1019
1020 void debug_dma_map_sg(struct device *dev, struct scatterlist *sg,
1021 int nents, int mapped_ents, int direction)
1022 {
1023 struct dma_debug_entry *entry;
1024 struct scatterlist *s;
1025 int i;
1026
1027 if (unlikely(global_disable))
1028 return;
1029
1030 for_each_sg(sg, s, mapped_ents, i) {
1031 entry = dma_entry_alloc();
1032 if (!entry)
1033 return;
1034
1035 entry->type = dma_debug_sg;
1036 entry->dev = dev;
1037 entry->paddr = sg_phys(s);
1038 entry->size = sg_dma_len(s);
1039 entry->dev_addr = sg_dma_address(s);
1040 entry->direction = direction;
1041 entry->sg_call_ents = nents;
1042 entry->sg_mapped_ents = mapped_ents;
1043
1044 if (!PageHighMem(sg_page(s))) {
1045 check_for_stack(dev, sg_virt(s));
1046 check_for_illegal_area(dev, sg_virt(s), sg_dma_len(s));
1047 }
1048
1049 add_dma_entry(entry);
1050 }
1051 }
1052 EXPORT_SYMBOL(debug_dma_map_sg);
1053
1054 static int get_nr_mapped_entries(struct device *dev,
1055 struct dma_debug_entry *ref)
1056 {
1057 struct dma_debug_entry *entry;
1058 struct hash_bucket *bucket;
1059 unsigned long flags;
1060 int mapped_ents;
1061
1062 bucket = get_hash_bucket(ref, &flags);
1063 entry = hash_bucket_find(bucket, ref);
1064 mapped_ents = 0;
1065
1066 if (entry)
1067 mapped_ents = entry->sg_mapped_ents;
1068 put_hash_bucket(bucket, &flags);
1069
1070 return mapped_ents;
1071 }
1072
1073 void debug_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
1074 int nelems, int dir)
1075 {
1076 struct scatterlist *s;
1077 int mapped_ents = 0, i;
1078
1079 if (unlikely(global_disable))
1080 return;
1081
1082 for_each_sg(sglist, s, nelems, i) {
1083
1084 struct dma_debug_entry ref = {
1085 .type = dma_debug_sg,
1086 .dev = dev,
1087 .paddr = sg_phys(s),
1088 .dev_addr = sg_dma_address(s),
1089 .size = sg_dma_len(s),
1090 .direction = dir,
1091 .sg_call_ents = nelems,
1092 };
1093
1094 if (mapped_ents && i >= mapped_ents)
1095 break;
1096
1097 if (!i)
1098 mapped_ents = get_nr_mapped_entries(dev, &ref);
1099
1100 check_unmap(&ref);
1101 }
1102 }
1103 EXPORT_SYMBOL(debug_dma_unmap_sg);
1104
1105 void debug_dma_alloc_coherent(struct device *dev, size_t size,
1106 dma_addr_t dma_addr, void *virt)
1107 {
1108 struct dma_debug_entry *entry;
1109
1110 if (unlikely(global_disable))
1111 return;
1112
1113 if (unlikely(virt == NULL))
1114 return;
1115
1116 entry = dma_entry_alloc();
1117 if (!entry)
1118 return;
1119
1120 entry->type = dma_debug_coherent;
1121 entry->dev = dev;
1122 entry->paddr = virt_to_phys(virt);
1123 entry->size = size;
1124 entry->dev_addr = dma_addr;
1125 entry->direction = DMA_BIDIRECTIONAL;
1126
1127 add_dma_entry(entry);
1128 }
1129 EXPORT_SYMBOL(debug_dma_alloc_coherent);
1130
1131 void debug_dma_free_coherent(struct device *dev, size_t size,
1132 void *virt, dma_addr_t addr)
1133 {
1134 struct dma_debug_entry ref = {
1135 .type = dma_debug_coherent,
1136 .dev = dev,
1137 .paddr = virt_to_phys(virt),
1138 .dev_addr = addr,
1139 .size = size,
1140 .direction = DMA_BIDIRECTIONAL,
1141 };
1142
1143 if (unlikely(global_disable))
1144 return;
1145
1146 check_unmap(&ref);
1147 }
1148 EXPORT_SYMBOL(debug_dma_free_coherent);
1149
1150 void debug_dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_handle,
1151 size_t size, int direction)
1152 {
1153 struct dma_debug_entry ref;
1154
1155 if (unlikely(global_disable))
1156 return;
1157
1158 ref.type = dma_debug_single;
1159 ref.dev = dev;
1160 ref.dev_addr = dma_handle;
1161 ref.size = size;
1162 ref.direction = direction;
1163 ref.sg_call_ents = 0;
1164
1165 check_sync(dev, &ref, true);
1166 }
1167 EXPORT_SYMBOL(debug_dma_sync_single_for_cpu);
1168
1169 void debug_dma_sync_single_for_device(struct device *dev,
1170 dma_addr_t dma_handle, size_t size,
1171 int direction)
1172 {
1173 struct dma_debug_entry ref;
1174
1175 if (unlikely(global_disable))
1176 return;
1177
1178 ref.type = dma_debug_single;
1179 ref.dev = dev;
1180 ref.dev_addr = dma_handle;
1181 ref.size = size;
1182 ref.direction = direction;
1183 ref.sg_call_ents = 0;
1184
1185 check_sync(dev, &ref, false);
1186 }
1187 EXPORT_SYMBOL(debug_dma_sync_single_for_device);
1188
1189 void debug_dma_sync_single_range_for_cpu(struct device *dev,
1190 dma_addr_t dma_handle,
1191 unsigned long offset, size_t size,
1192 int direction)
1193 {
1194 struct dma_debug_entry ref;
1195
1196 if (unlikely(global_disable))
1197 return;
1198
1199 ref.type = dma_debug_single;
1200 ref.dev = dev;
1201 ref.dev_addr = dma_handle;
1202 ref.size = offset + size;
1203 ref.direction = direction;
1204 ref.sg_call_ents = 0;
1205
1206 check_sync(dev, &ref, true);
1207 }
1208 EXPORT_SYMBOL(debug_dma_sync_single_range_for_cpu);
1209
1210 void debug_dma_sync_single_range_for_device(struct device *dev,
1211 dma_addr_t dma_handle,
1212 unsigned long offset,
1213 size_t size, int direction)
1214 {
1215 struct dma_debug_entry ref;
1216
1217 if (unlikely(global_disable))
1218 return;
1219
1220 ref.type = dma_debug_single;
1221 ref.dev = dev;
1222 ref.dev_addr = dma_handle;
1223 ref.size = offset + size;
1224 ref.direction = direction;
1225 ref.sg_call_ents = 0;
1226
1227 check_sync(dev, &ref, false);
1228 }
1229 EXPORT_SYMBOL(debug_dma_sync_single_range_for_device);
1230
1231 void debug_dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
1232 int nelems, int direction)
1233 {
1234 struct scatterlist *s;
1235 int mapped_ents = 0, i;
1236
1237 if (unlikely(global_disable))
1238 return;
1239
1240 for_each_sg(sg, s, nelems, i) {
1241
1242 struct dma_debug_entry ref = {
1243 .type = dma_debug_sg,
1244 .dev = dev,
1245 .paddr = sg_phys(s),
1246 .dev_addr = sg_dma_address(s),
1247 .size = sg_dma_len(s),
1248 .direction = direction,
1249 .sg_call_ents = nelems,
1250 };
1251
1252 if (!i)
1253 mapped_ents = get_nr_mapped_entries(dev, &ref);
1254
1255 if (i >= mapped_ents)
1256 break;
1257
1258 check_sync(dev, &ref, true);
1259 }
1260 }
1261 EXPORT_SYMBOL(debug_dma_sync_sg_for_cpu);
1262
1263 void debug_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
1264 int nelems, int direction)
1265 {
1266 struct scatterlist *s;
1267 int mapped_ents = 0, i;
1268
1269 if (unlikely(global_disable))
1270 return;
1271
1272 for_each_sg(sg, s, nelems, i) {
1273
1274 struct dma_debug_entry ref = {
1275 .type = dma_debug_sg,
1276 .dev = dev,
1277 .paddr = sg_phys(s),
1278 .dev_addr = sg_dma_address(s),
1279 .size = sg_dma_len(s),
1280 .direction = direction,
1281 .sg_call_ents = nelems,
1282 };
1283 if (!i)
1284 mapped_ents = get_nr_mapped_entries(dev, &ref);
1285
1286 if (i >= mapped_ents)
1287 break;
1288
1289 check_sync(dev, &ref, false);
1290 }
1291 }
1292 EXPORT_SYMBOL(debug_dma_sync_sg_for_device);
1293
1294 static int __init dma_debug_driver_setup(char *str)
1295 {
1296 int i;
1297
1298 for (i = 0; i < NAME_MAX_LEN - 1; ++i, ++str) {
1299 current_driver_name[i] = *str;
1300 if (*str == 0)
1301 break;
1302 }
1303
1304 if (current_driver_name[0])
1305 pr_info("DMA-API: enable driver filter for driver [%s]\n",
1306 current_driver_name);
1307
1308
1309 return 1;
1310 }
1311 __setup("dma_debug_driver=", dma_debug_driver_setup);
Linux Btrfs Development