dma-debug: Fix compile warning with PAE enabled
[linux-2.6.git] / lib / dma-debug.c
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. Therfore 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; ++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 const struct file_operations filter_fops = {
591         .read  = filter_read,
592         .write = filter_write,
593 };
594
595 static int dma_debug_fs_init(void)
596 {
597         dma_debug_dent = debugfs_create_dir("dma-api", NULL);
598         if (!dma_debug_dent) {
599                 pr_err("DMA-API: can not create debugfs directory\n");
600                 return -ENOMEM;
601         }
602
603         global_disable_dent = debugfs_create_bool("disabled", 0444,
604                         dma_debug_dent,
605                         (u32 *)&global_disable);
606         if (!global_disable_dent)
607                 goto out_err;
608
609         error_count_dent = debugfs_create_u32("error_count", 0444,
610                         dma_debug_dent, &error_count);
611         if (!error_count_dent)
612                 goto out_err;
613
614         show_all_errors_dent = debugfs_create_u32("all_errors", 0644,
615                         dma_debug_dent,
616                         &show_all_errors);
617         if (!show_all_errors_dent)
618                 goto out_err;
619
620         show_num_errors_dent = debugfs_create_u32("num_errors", 0644,
621                         dma_debug_dent,
622                         &show_num_errors);
623         if (!show_num_errors_dent)
624                 goto out_err;
625
626         num_free_entries_dent = debugfs_create_u32("num_free_entries", 0444,
627                         dma_debug_dent,
628                         &num_free_entries);
629         if (!num_free_entries_dent)
630                 goto out_err;
631
632         min_free_entries_dent = debugfs_create_u32("min_free_entries", 0444,
633                         dma_debug_dent,
634                         &min_free_entries);
635         if (!min_free_entries_dent)
636                 goto out_err;
637
638         filter_dent = debugfs_create_file("driver_filter", 0644,
639                                           dma_debug_dent, NULL, &filter_fops);
640         if (!filter_dent)
641                 goto out_err;
642
643         return 0;
644
645 out_err:
646         debugfs_remove_recursive(dma_debug_dent);
647
648         return -ENOMEM;
649 }
650
651 static int device_dma_allocations(struct device *dev)
652 {
653         struct dma_debug_entry *entry;
654         unsigned long flags;
655         int count = 0, i;
656
657         local_irq_save(flags);
658
659         for (i = 0; i < HASH_SIZE; ++i) {
660                 spin_lock(&dma_entry_hash[i].lock);
661                 list_for_each_entry(entry, &dma_entry_hash[i].list, list) {
662                         if (entry->dev == dev)
663                                 count += 1;
664                 }
665                 spin_unlock(&dma_entry_hash[i].lock);
666         }
667
668         local_irq_restore(flags);
669
670         return count;
671 }
672
673 static int dma_debug_device_change(struct notifier_block *nb,
674                                     unsigned long action, void *data)
675 {
676         struct device *dev = data;
677         int count;
678
679
680         switch (action) {
681         case BUS_NOTIFY_UNBOUND_DRIVER:
682                 count = device_dma_allocations(dev);
683                 if (count == 0)
684                         break;
685                 err_printk(dev, NULL, "DMA-API: device driver has pending "
686                                 "DMA allocations while released from device "
687                                 "[count=%d]\n", count);
688                 break;
689         default:
690                 break;
691         }
692
693         return 0;
694 }
695
696 void dma_debug_add_bus(struct bus_type *bus)
697 {
698         struct notifier_block *nb;
699
700         nb = kzalloc(sizeof(struct notifier_block), GFP_KERNEL);
701         if (nb == NULL) {
702                 pr_err("dma_debug_add_bus: out of memory\n");
703                 return;
704         }
705
706         nb->notifier_call = dma_debug_device_change;
707
708         bus_register_notifier(bus, nb);
709 }
710
711 /*
712  * Let the architectures decide how many entries should be preallocated.
713  */
714 void dma_debug_init(u32 num_entries)
715 {
716         int i;
717
718         if (global_disable)
719                 return;
720
721         for (i = 0; i < HASH_SIZE; ++i) {
722                 INIT_LIST_HEAD(&dma_entry_hash[i].list);
723                 spin_lock_init(&dma_entry_hash[i].lock);
724         }
725
726         if (dma_debug_fs_init() != 0) {
727                 pr_err("DMA-API: error creating debugfs entries - disabling\n");
728                 global_disable = true;
729
730                 return;
731         }
732
733         if (req_entries)
734                 num_entries = req_entries;
735
736         if (prealloc_memory(num_entries) != 0) {
737                 pr_err("DMA-API: debugging out of memory error - disabled\n");
738                 global_disable = true;
739
740                 return;
741         }
742
743         nr_total_entries = num_free_entries;
744
745         pr_info("DMA-API: debugging enabled by kernel config\n");
746 }
747
748 static __init int dma_debug_cmdline(char *str)
749 {
750         if (!str)
751                 return -EINVAL;
752
753         if (strncmp(str, "off", 3) == 0) {
754                 pr_info("DMA-API: debugging disabled on kernel command line\n");
755                 global_disable = true;
756         }
757
758         return 0;
759 }
760
761 static __init int dma_debug_entries_cmdline(char *str)
762 {
763         int res;
764
765         if (!str)
766                 return -EINVAL;
767
768         res = get_option(&str, &req_entries);
769
770         if (!res)
771                 req_entries = 0;
772
773         return 0;
774 }
775
776 __setup("dma_debug=", dma_debug_cmdline);
777 __setup("dma_debug_entries=", dma_debug_entries_cmdline);
778
779 static void check_unmap(struct dma_debug_entry *ref)
780 {
781         struct dma_debug_entry *entry;
782         struct hash_bucket *bucket;
783         unsigned long flags;
784
785         if (dma_mapping_error(ref->dev, ref->dev_addr)) {
786                 err_printk(ref->dev, NULL, "DMA-API: device driver tries "
787                            "to free an invalid DMA memory address\n");
788                 return;
789         }
790
791         bucket = get_hash_bucket(ref, &flags);
792         entry = hash_bucket_find(bucket, ref);
793
794         if (!entry) {
795                 err_printk(ref->dev, NULL, "DMA-API: device driver tries "
796                            "to free DMA memory it has not allocated "
797                            "[device address=0x%016llx] [size=%llu bytes]\n",
798                            ref->dev_addr, ref->size);
799                 goto out;
800         }
801
802         if (ref->size != entry->size) {
803                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
804                            "DMA memory with different size "
805                            "[device address=0x%016llx] [map size=%llu bytes] "
806                            "[unmap size=%llu bytes]\n",
807                            ref->dev_addr, entry->size, ref->size);
808         }
809
810         if (ref->type != entry->type) {
811                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
812                            "DMA memory with wrong function "
813                            "[device address=0x%016llx] [size=%llu bytes] "
814                            "[mapped as %s] [unmapped as %s]\n",
815                            ref->dev_addr, ref->size,
816                            type2name[entry->type], type2name[ref->type]);
817         } else if ((entry->type == dma_debug_coherent) &&
818                    (ref->paddr != entry->paddr)) {
819                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
820                            "DMA memory with different CPU address "
821                            "[device address=0x%016llx] [size=%llu bytes] "
822                            "[cpu alloc address=0x%016llx] "
823                            "[cpu free address=0x%016llx]",
824                            ref->dev_addr, ref->size,
825                            (unsigned long long)entry->paddr,
826                            (unsigned long long)ref->paddr);
827         }
828
829         if (ref->sg_call_ents && ref->type == dma_debug_sg &&
830             ref->sg_call_ents != entry->sg_call_ents) {
831                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
832                            "DMA sg list with different entry count "
833                            "[map count=%d] [unmap count=%d]\n",
834                            entry->sg_call_ents, ref->sg_call_ents);
835         }
836
837         /*
838          * This may be no bug in reality - but most implementations of the
839          * DMA API don't handle this properly, so check for it here
840          */
841         if (ref->direction != entry->direction) {
842                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
843                            "DMA memory with different direction "
844                            "[device address=0x%016llx] [size=%llu bytes] "
845                            "[mapped with %s] [unmapped with %s]\n",
846                            ref->dev_addr, ref->size,
847                            dir2name[entry->direction],
848                            dir2name[ref->direction]);
849         }
850
851         hash_bucket_del(entry);
852         dma_entry_free(entry);
853
854 out:
855         put_hash_bucket(bucket, &flags);
856 }
857
858 static void check_for_stack(struct device *dev, void *addr)
859 {
860         if (object_is_on_stack(addr))
861                 err_printk(dev, NULL, "DMA-API: device driver maps memory from"
862                                 "stack [addr=%p]\n", addr);
863 }
864
865 static inline bool overlap(void *addr, unsigned long len, void *start, void *end)
866 {
867         unsigned long a1 = (unsigned long)addr;
868         unsigned long b1 = a1 + len;
869         unsigned long a2 = (unsigned long)start;
870         unsigned long b2 = (unsigned long)end;
871
872         return !(b1 <= a2 || a1 >= b2);
873 }
874
875 static void check_for_illegal_area(struct device *dev, void *addr, unsigned long len)
876 {
877         if (overlap(addr, len, _text, _etext) ||
878             overlap(addr, len, __start_rodata, __end_rodata))
879                 err_printk(dev, NULL, "DMA-API: device driver maps memory from kernel text or rodata [addr=%p] [len=%lu]\n", addr, len);
880 }
881
882 static void check_sync(struct device *dev,
883                        struct dma_debug_entry *ref,
884                        bool to_cpu)
885 {
886         struct dma_debug_entry *entry;
887         struct hash_bucket *bucket;
888         unsigned long flags;
889
890         bucket = get_hash_bucket(ref, &flags);
891
892         entry = hash_bucket_find(bucket, ref);
893
894         if (!entry) {
895                 err_printk(dev, NULL, "DMA-API: device driver tries "
896                                 "to sync DMA memory it has not allocated "
897                                 "[device address=0x%016llx] [size=%llu bytes]\n",
898                                 (unsigned long long)ref->dev_addr, ref->size);
899                 goto out;
900         }
901
902         if (ref->size > entry->size) {
903                 err_printk(dev, entry, "DMA-API: device driver syncs"
904                                 " DMA memory outside allocated range "
905                                 "[device address=0x%016llx] "
906                                 "[allocation size=%llu bytes] "
907                                 "[sync offset+size=%llu]\n",
908                                 entry->dev_addr, entry->size,
909                                 ref->size);
910         }
911
912         if (ref->direction != entry->direction) {
913                 err_printk(dev, entry, "DMA-API: device driver syncs "
914                                 "DMA memory with different direction "
915                                 "[device address=0x%016llx] [size=%llu bytes] "
916                                 "[mapped with %s] [synced with %s]\n",
917                                 (unsigned long long)ref->dev_addr, entry->size,
918                                 dir2name[entry->direction],
919                                 dir2name[ref->direction]);
920         }
921
922         if (entry->direction == DMA_BIDIRECTIONAL)
923                 goto out;
924
925         if (to_cpu && !(entry->direction == DMA_FROM_DEVICE) &&
926                       !(ref->direction == DMA_TO_DEVICE))
927                 err_printk(dev, entry, "DMA-API: device driver syncs "
928                                 "device read-only DMA memory for cpu "
929                                 "[device address=0x%016llx] [size=%llu bytes] "
930                                 "[mapped with %s] [synced with %s]\n",
931                                 (unsigned long long)ref->dev_addr, entry->size,
932                                 dir2name[entry->direction],
933                                 dir2name[ref->direction]);
934
935         if (!to_cpu && !(entry->direction == DMA_TO_DEVICE) &&
936                        !(ref->direction == DMA_FROM_DEVICE))
937                 err_printk(dev, entry, "DMA-API: device driver syncs "
938                                 "device write-only DMA memory to device "
939                                 "[device address=0x%016llx] [size=%llu bytes] "
940                                 "[mapped with %s] [synced with %s]\n",
941                                 (unsigned long long)ref->dev_addr, entry->size,
942                                 dir2name[entry->direction],
943                                 dir2name[ref->direction]);
944
945 out:
946         put_hash_bucket(bucket, &flags);
947
948 }
949
950 void debug_dma_map_page(struct device *dev, struct page *page, size_t offset,
951                         size_t size, int direction, dma_addr_t dma_addr,
952                         bool map_single)
953 {
954         struct dma_debug_entry *entry;
955
956         if (unlikely(global_disable))
957                 return;
958
959         if (unlikely(dma_mapping_error(dev, dma_addr)))
960                 return;
961
962         entry = dma_entry_alloc();
963         if (!entry)
964                 return;
965
966         entry->dev       = dev;
967         entry->type      = dma_debug_page;
968         entry->paddr     = page_to_phys(page) + offset;
969         entry->dev_addr  = dma_addr;
970         entry->size      = size;
971         entry->direction = direction;
972
973         if (map_single)
974                 entry->type = dma_debug_single;
975
976         if (!PageHighMem(page)) {
977                 void *addr = page_address(page) + offset;
978
979                 check_for_stack(dev, addr);
980                 check_for_illegal_area(dev, addr, size);
981         }
982
983         add_dma_entry(entry);
984 }
985 EXPORT_SYMBOL(debug_dma_map_page);
986
987 void debug_dma_unmap_page(struct device *dev, dma_addr_t addr,
988                           size_t size, int direction, bool map_single)
989 {
990         struct dma_debug_entry ref = {
991                 .type           = dma_debug_page,
992                 .dev            = dev,
993                 .dev_addr       = addr,
994                 .size           = size,
995                 .direction      = direction,
996         };
997
998         if (unlikely(global_disable))
999                 return;
1000
1001         if (map_single)
1002                 ref.type = dma_debug_single;
1003
1004         check_unmap(&ref);
1005 }
1006 EXPORT_SYMBOL(debug_dma_unmap_page);
1007
1008 void debug_dma_map_sg(struct device *dev, struct scatterlist *sg,
1009                       int nents, int mapped_ents, int direction)
1010 {
1011         struct dma_debug_entry *entry;
1012         struct scatterlist *s;
1013         int i;
1014
1015         if (unlikely(global_disable))
1016                 return;
1017
1018         for_each_sg(sg, s, mapped_ents, i) {
1019                 entry = dma_entry_alloc();
1020                 if (!entry)
1021                         return;
1022
1023                 entry->type           = dma_debug_sg;
1024                 entry->dev            = dev;
1025                 entry->paddr          = sg_phys(s);
1026                 entry->size           = sg_dma_len(s);
1027                 entry->dev_addr       = sg_dma_address(s);
1028                 entry->direction      = direction;
1029                 entry->sg_call_ents   = nents;
1030                 entry->sg_mapped_ents = mapped_ents;
1031
1032                 if (!PageHighMem(sg_page(s))) {
1033                         check_for_stack(dev, sg_virt(s));
1034                         check_for_illegal_area(dev, sg_virt(s), sg_dma_len(s));
1035                 }
1036
1037                 add_dma_entry(entry);
1038         }
1039 }
1040 EXPORT_SYMBOL(debug_dma_map_sg);
1041
1042 static int get_nr_mapped_entries(struct device *dev,
1043                                  struct dma_debug_entry *ref)
1044 {
1045         struct dma_debug_entry *entry;
1046         struct hash_bucket *bucket;
1047         unsigned long flags;
1048         int mapped_ents;
1049
1050         bucket       = get_hash_bucket(ref, &flags);
1051         entry        = hash_bucket_find(bucket, ref);
1052         mapped_ents  = 0;
1053
1054         if (entry)
1055                 mapped_ents = entry->sg_mapped_ents;
1056         put_hash_bucket(bucket, &flags);
1057
1058         return mapped_ents;
1059 }
1060
1061 void debug_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
1062                         int nelems, int dir)
1063 {
1064         struct scatterlist *s;
1065         int mapped_ents = 0, i;
1066
1067         if (unlikely(global_disable))
1068                 return;
1069
1070         for_each_sg(sglist, s, nelems, i) {
1071
1072                 struct dma_debug_entry ref = {
1073                         .type           = dma_debug_sg,
1074                         .dev            = dev,
1075                         .paddr          = sg_phys(s),
1076                         .dev_addr       = sg_dma_address(s),
1077                         .size           = sg_dma_len(s),
1078                         .direction      = dir,
1079                         .sg_call_ents   = nelems,
1080                 };
1081
1082                 if (mapped_ents && i >= mapped_ents)
1083                         break;
1084
1085                 if (!i)
1086                         mapped_ents = get_nr_mapped_entries(dev, &ref);
1087
1088                 check_unmap(&ref);
1089         }
1090 }
1091 EXPORT_SYMBOL(debug_dma_unmap_sg);
1092
1093 void debug_dma_alloc_coherent(struct device *dev, size_t size,
1094                               dma_addr_t dma_addr, void *virt)
1095 {
1096         struct dma_debug_entry *entry;
1097
1098         if (unlikely(global_disable))
1099                 return;
1100
1101         if (unlikely(virt == NULL))
1102                 return;
1103
1104         entry = dma_entry_alloc();
1105         if (!entry)
1106                 return;
1107
1108         entry->type      = dma_debug_coherent;
1109         entry->dev       = dev;
1110         entry->paddr     = virt_to_phys(virt);
1111         entry->size      = size;
1112         entry->dev_addr  = dma_addr;
1113         entry->direction = DMA_BIDIRECTIONAL;
1114
1115         add_dma_entry(entry);
1116 }
1117 EXPORT_SYMBOL(debug_dma_alloc_coherent);
1118
1119 void debug_dma_free_coherent(struct device *dev, size_t size,
1120                          void *virt, dma_addr_t addr)
1121 {
1122         struct dma_debug_entry ref = {
1123                 .type           = dma_debug_coherent,
1124                 .dev            = dev,
1125                 .paddr          = virt_to_phys(virt),
1126                 .dev_addr       = addr,
1127                 .size           = size,
1128                 .direction      = DMA_BIDIRECTIONAL,
1129         };
1130
1131         if (unlikely(global_disable))
1132                 return;
1133
1134         check_unmap(&ref);
1135 }
1136 EXPORT_SYMBOL(debug_dma_free_coherent);
1137
1138 void debug_dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_handle,
1139                                    size_t size, int direction)
1140 {
1141         struct dma_debug_entry ref;
1142
1143         if (unlikely(global_disable))
1144                 return;
1145
1146         ref.type         = dma_debug_single;
1147         ref.dev          = dev;
1148         ref.dev_addr     = dma_handle;
1149         ref.size         = size;
1150         ref.direction    = direction;
1151         ref.sg_call_ents = 0;
1152
1153         check_sync(dev, &ref, true);
1154 }
1155 EXPORT_SYMBOL(debug_dma_sync_single_for_cpu);
1156
1157 void debug_dma_sync_single_for_device(struct device *dev,
1158                                       dma_addr_t dma_handle, size_t size,
1159                                       int direction)
1160 {
1161         struct dma_debug_entry ref;
1162
1163         if (unlikely(global_disable))
1164                 return;
1165
1166         ref.type         = dma_debug_single;
1167         ref.dev          = dev;
1168         ref.dev_addr     = dma_handle;
1169         ref.size         = size;
1170         ref.direction    = direction;
1171         ref.sg_call_ents = 0;
1172
1173         check_sync(dev, &ref, false);
1174 }
1175 EXPORT_SYMBOL(debug_dma_sync_single_for_device);
1176
1177 void debug_dma_sync_single_range_for_cpu(struct device *dev,
1178                                          dma_addr_t dma_handle,
1179                                          unsigned long offset, size_t size,
1180                                          int direction)
1181 {
1182         struct dma_debug_entry ref;
1183
1184         if (unlikely(global_disable))
1185                 return;
1186
1187         ref.type         = dma_debug_single;
1188         ref.dev          = dev;
1189         ref.dev_addr     = dma_handle;
1190         ref.size         = offset + size;
1191         ref.direction    = direction;
1192         ref.sg_call_ents = 0;
1193
1194         check_sync(dev, &ref, true);
1195 }
1196 EXPORT_SYMBOL(debug_dma_sync_single_range_for_cpu);
1197
1198 void debug_dma_sync_single_range_for_device(struct device *dev,
1199                                             dma_addr_t dma_handle,
1200                                             unsigned long offset,
1201                                             size_t size, int direction)
1202 {
1203         struct dma_debug_entry ref;
1204
1205         if (unlikely(global_disable))
1206                 return;
1207
1208         ref.type         = dma_debug_single;
1209         ref.dev          = dev;
1210         ref.dev_addr     = dma_handle;
1211         ref.size         = offset + size;
1212         ref.direction    = direction;
1213         ref.sg_call_ents = 0;
1214
1215         check_sync(dev, &ref, false);
1216 }
1217 EXPORT_SYMBOL(debug_dma_sync_single_range_for_device);
1218
1219 void debug_dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
1220                                int nelems, int direction)
1221 {
1222         struct scatterlist *s;
1223         int mapped_ents = 0, i;
1224
1225         if (unlikely(global_disable))
1226                 return;
1227
1228         for_each_sg(sg, s, nelems, i) {
1229
1230                 struct dma_debug_entry ref = {
1231                         .type           = dma_debug_sg,
1232                         .dev            = dev,
1233                         .paddr          = sg_phys(s),
1234                         .dev_addr       = sg_dma_address(s),
1235                         .size           = sg_dma_len(s),
1236                         .direction      = direction,
1237                         .sg_call_ents   = nelems,
1238                 };
1239
1240                 if (!i)
1241                         mapped_ents = get_nr_mapped_entries(dev, &ref);
1242
1243                 if (i >= mapped_ents)
1244                         break;
1245
1246                 check_sync(dev, &ref, true);
1247         }
1248 }
1249 EXPORT_SYMBOL(debug_dma_sync_sg_for_cpu);
1250
1251 void debug_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
1252                                   int nelems, int direction)
1253 {
1254         struct scatterlist *s;
1255         int mapped_ents = 0, i;
1256
1257         if (unlikely(global_disable))
1258                 return;
1259
1260         for_each_sg(sg, s, nelems, i) {
1261
1262                 struct dma_debug_entry ref = {
1263                         .type           = dma_debug_sg,
1264                         .dev            = dev,
1265                         .paddr          = sg_phys(s),
1266                         .dev_addr       = sg_dma_address(s),
1267                         .size           = sg_dma_len(s),
1268                         .direction      = direction,
1269                         .sg_call_ents   = nelems,
1270                 };
1271                 if (!i)
1272                         mapped_ents = get_nr_mapped_entries(dev, &ref);
1273
1274                 if (i >= mapped_ents)
1275                         break;
1276
1277                 check_sync(dev, &ref, false);
1278         }
1279 }
1280 EXPORT_SYMBOL(debug_dma_sync_sg_for_device);
1281
1282 static int __init dma_debug_driver_setup(char *str)
1283 {
1284         int i;
1285
1286         for (i = 0; i < NAME_MAX_LEN - 1; ++i, ++str) {
1287                 current_driver_name[i] = *str;
1288                 if (*str == 0)
1289                         break;
1290         }
1291
1292         if (current_driver_name[0])
1293                 pr_info("DMA-API: enable driver filter for driver [%s]\n",
1294                         current_driver_name);
1295
1296
1297         return 1;
1298 }
1299 __setup("dma_debug_driver=", dma_debug_driver_setup);