dma-debug: disable/enable irqs only once in device_dma_allocations
[linux-3.10.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         /* driver filter off */
151         if (likely(!current_driver_name[0]))
152                 return true;
153
154         /* driver filter on and initialized */
155         if (current_driver && dev->driver == current_driver)
156                 return true;
157
158         /* driver filter on but not yet initialized */
159         if (!current_driver && current_driver_name[0]) {
160                 struct device_driver *drv = get_driver(dev->driver);
161                 unsigned long flags;
162                 bool ret = false;
163
164                 if (!drv)
165                         return false;
166
167                 /* lock to protect against change of current_driver_name */
168                 read_lock_irqsave(&driver_name_lock, flags);
169
170                 if (drv->name &&
171                     strncmp(current_driver_name, drv->name,
172                             NAME_MAX_LEN-1) == 0) {
173                         current_driver = drv;
174                         ret = true;
175                 }
176
177                 read_unlock_irqrestore(&driver_name_lock, flags);
178                 put_driver(drv);
179
180                 return ret;
181         }
182
183         return false;
184 }
185
186 #define err_printk(dev, entry, format, arg...) do {             \
187                 error_count += 1;                               \
188                 if (driver_filter(dev) &&                       \
189                     (show_all_errors || show_num_errors > 0)) { \
190                         WARN(1, "%s %s: " format,               \
191                              dev_driver_string(dev),            \
192                              dev_name(dev) , ## arg);           \
193                         dump_entry_trace(entry);                \
194                 }                                               \
195                 if (!show_all_errors && show_num_errors > 0)    \
196                         show_num_errors -= 1;                   \
197         } while (0);
198
199 /*
200  * Hash related functions
201  *
202  * Every DMA-API request is saved into a struct dma_debug_entry. To
203  * have quick access to these structs they are stored into a hash.
204  */
205 static int hash_fn(struct dma_debug_entry *entry)
206 {
207         /*
208          * Hash function is based on the dma address.
209          * We use bits 20-27 here as the index into the hash
210          */
211         return (entry->dev_addr >> HASH_FN_SHIFT) & HASH_FN_MASK;
212 }
213
214 /*
215  * Request exclusive access to a hash bucket for a given dma_debug_entry.
216  */
217 static struct hash_bucket *get_hash_bucket(struct dma_debug_entry *entry,
218                                            unsigned long *flags)
219 {
220         int idx = hash_fn(entry);
221         unsigned long __flags;
222
223         spin_lock_irqsave(&dma_entry_hash[idx].lock, __flags);
224         *flags = __flags;
225         return &dma_entry_hash[idx];
226 }
227
228 /*
229  * Give up exclusive access to the hash bucket
230  */
231 static void put_hash_bucket(struct hash_bucket *bucket,
232                             unsigned long *flags)
233 {
234         unsigned long __flags = *flags;
235
236         spin_unlock_irqrestore(&bucket->lock, __flags);
237 }
238
239 /*
240  * Search a given entry in the hash bucket list
241  */
242 static struct dma_debug_entry *hash_bucket_find(struct hash_bucket *bucket,
243                                                 struct dma_debug_entry *ref)
244 {
245         struct dma_debug_entry *entry, *ret = NULL;
246         int matches = 0, match_lvl, last_lvl = 0;
247
248         list_for_each_entry(entry, &bucket->list, list) {
249                 if ((entry->dev_addr != ref->dev_addr) ||
250                     (entry->dev != ref->dev))
251                         continue;
252
253                 /*
254                  * Some drivers map the same physical address multiple
255                  * times. Without a hardware IOMMU this results in the
256                  * same device addresses being put into the dma-debug
257                  * hash multiple times too. This can result in false
258                  * positives being reported. Therfore we implement a
259                  * best-fit algorithm here which returns the entry from
260                  * the hash which fits best to the reference value
261                  * instead of the first-fit.
262                  */
263                 matches += 1;
264                 match_lvl = 0;
265                 entry->size      == ref->size      ? ++match_lvl : match_lvl;
266                 entry->type      == ref->type      ? ++match_lvl : match_lvl;
267                 entry->direction == ref->direction ? ++match_lvl : match_lvl;
268
269                 if (match_lvl == 3) {
270                         /* perfect-fit - return the result */
271                         return entry;
272                 } else if (match_lvl > last_lvl) {
273                         /*
274                          * We found an entry that fits better then the
275                          * previous one
276                          */
277                         last_lvl = match_lvl;
278                         ret      = entry;
279                 }
280         }
281
282         /*
283          * If we have multiple matches but no perfect-fit, just return
284          * NULL.
285          */
286         ret = (matches == 1) ? ret : NULL;
287
288         return ret;
289 }
290
291 /*
292  * Add an entry to a hash bucket
293  */
294 static void hash_bucket_add(struct hash_bucket *bucket,
295                             struct dma_debug_entry *entry)
296 {
297         list_add_tail(&entry->list, &bucket->list);
298 }
299
300 /*
301  * Remove entry from a hash bucket list
302  */
303 static void hash_bucket_del(struct dma_debug_entry *entry)
304 {
305         list_del(&entry->list);
306 }
307
308 /*
309  * Dump mapping entries for debugging purposes
310  */
311 void debug_dma_dump_mappings(struct device *dev)
312 {
313         int idx;
314
315         for (idx = 0; idx < HASH_SIZE; idx++) {
316                 struct hash_bucket *bucket = &dma_entry_hash[idx];
317                 struct dma_debug_entry *entry;
318                 unsigned long flags;
319
320                 spin_lock_irqsave(&bucket->lock, flags);
321
322                 list_for_each_entry(entry, &bucket->list, list) {
323                         if (!dev || dev == entry->dev) {
324                                 dev_info(entry->dev,
325                                          "%s idx %d P=%Lx D=%Lx L=%Lx %s\n",
326                                          type2name[entry->type], idx,
327                                          (unsigned long long)entry->paddr,
328                                          entry->dev_addr, entry->size,
329                                          dir2name[entry->direction]);
330                         }
331                 }
332
333                 spin_unlock_irqrestore(&bucket->lock, flags);
334         }
335 }
336 EXPORT_SYMBOL(debug_dma_dump_mappings);
337
338 /*
339  * Wrapper function for adding an entry to the hash.
340  * This function takes care of locking itself.
341  */
342 static void add_dma_entry(struct dma_debug_entry *entry)
343 {
344         struct hash_bucket *bucket;
345         unsigned long flags;
346
347         bucket = get_hash_bucket(entry, &flags);
348         hash_bucket_add(bucket, entry);
349         put_hash_bucket(bucket, &flags);
350 }
351
352 static struct dma_debug_entry *__dma_entry_alloc(void)
353 {
354         struct dma_debug_entry *entry;
355
356         entry = list_entry(free_entries.next, struct dma_debug_entry, list);
357         list_del(&entry->list);
358         memset(entry, 0, sizeof(*entry));
359
360         num_free_entries -= 1;
361         if (num_free_entries < min_free_entries)
362                 min_free_entries = num_free_entries;
363
364         return entry;
365 }
366
367 /* struct dma_entry allocator
368  *
369  * The next two functions implement the allocator for
370  * struct dma_debug_entries.
371  */
372 static struct dma_debug_entry *dma_entry_alloc(void)
373 {
374         struct dma_debug_entry *entry = NULL;
375         unsigned long flags;
376
377         spin_lock_irqsave(&free_entries_lock, flags);
378
379         if (list_empty(&free_entries)) {
380                 pr_err("DMA-API: debugging out of memory - disabling\n");
381                 global_disable = true;
382                 goto out;
383         }
384
385         entry = __dma_entry_alloc();
386
387 #ifdef CONFIG_STACKTRACE
388         entry->stacktrace.max_entries = DMA_DEBUG_STACKTRACE_ENTRIES;
389         entry->stacktrace.entries = entry->st_entries;
390         entry->stacktrace.skip = 2;
391         save_stack_trace(&entry->stacktrace);
392 #endif
393
394 out:
395         spin_unlock_irqrestore(&free_entries_lock, flags);
396
397         return entry;
398 }
399
400 static void dma_entry_free(struct dma_debug_entry *entry)
401 {
402         unsigned long flags;
403
404         /*
405          * add to beginning of the list - this way the entries are
406          * more likely cache hot when they are reallocated.
407          */
408         spin_lock_irqsave(&free_entries_lock, flags);
409         list_add(&entry->list, &free_entries);
410         num_free_entries += 1;
411         spin_unlock_irqrestore(&free_entries_lock, flags);
412 }
413
414 int dma_debug_resize_entries(u32 num_entries)
415 {
416         int i, delta, ret = 0;
417         unsigned long flags;
418         struct dma_debug_entry *entry;
419         LIST_HEAD(tmp);
420
421         spin_lock_irqsave(&free_entries_lock, flags);
422
423         if (nr_total_entries < num_entries) {
424                 delta = num_entries - nr_total_entries;
425
426                 spin_unlock_irqrestore(&free_entries_lock, flags);
427
428                 for (i = 0; i < delta; i++) {
429                         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
430                         if (!entry)
431                                 break;
432
433                         list_add_tail(&entry->list, &tmp);
434                 }
435
436                 spin_lock_irqsave(&free_entries_lock, flags);
437
438                 list_splice(&tmp, &free_entries);
439                 nr_total_entries += i;
440                 num_free_entries += i;
441         } else {
442                 delta = nr_total_entries - num_entries;
443
444                 for (i = 0; i < delta && !list_empty(&free_entries); i++) {
445                         entry = __dma_entry_alloc();
446                         kfree(entry);
447                 }
448
449                 nr_total_entries -= i;
450         }
451
452         if (nr_total_entries != num_entries)
453                 ret = 1;
454
455         spin_unlock_irqrestore(&free_entries_lock, flags);
456
457         return ret;
458 }
459 EXPORT_SYMBOL(dma_debug_resize_entries);
460
461 /*
462  * DMA-API debugging init code
463  *
464  * The init code does two things:
465  *   1. Initialize core data structures
466  *   2. Preallocate a given number of dma_debug_entry structs
467  */
468
469 static int prealloc_memory(u32 num_entries)
470 {
471         struct dma_debug_entry *entry, *next_entry;
472         int i;
473
474         for (i = 0; i < num_entries; ++i) {
475                 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
476                 if (!entry)
477                         goto out_err;
478
479                 list_add_tail(&entry->list, &free_entries);
480         }
481
482         num_free_entries = num_entries;
483         min_free_entries = num_entries;
484
485         pr_info("DMA-API: preallocated %d debug entries\n", num_entries);
486
487         return 0;
488
489 out_err:
490
491         list_for_each_entry_safe(entry, next_entry, &free_entries, list) {
492                 list_del(&entry->list);
493                 kfree(entry);
494         }
495
496         return -ENOMEM;
497 }
498
499 static ssize_t filter_read(struct file *file, char __user *user_buf,
500                            size_t count, loff_t *ppos)
501 {
502         char buf[NAME_MAX_LEN + 1];
503         unsigned long flags;
504         int len;
505
506         if (!current_driver_name[0])
507                 return 0;
508
509         /*
510          * We can't copy to userspace directly because current_driver_name can
511          * only be read under the driver_name_lock with irqs disabled. So
512          * create a temporary copy first.
513          */
514         read_lock_irqsave(&driver_name_lock, flags);
515         len = scnprintf(buf, NAME_MAX_LEN + 1, "%s\n", current_driver_name);
516         read_unlock_irqrestore(&driver_name_lock, flags);
517
518         return simple_read_from_buffer(user_buf, count, ppos, buf, len);
519 }
520
521 static ssize_t filter_write(struct file *file, const char __user *userbuf,
522                             size_t count, loff_t *ppos)
523 {
524         char buf[NAME_MAX_LEN];
525         unsigned long flags;
526         size_t len;
527         int i;
528
529         /*
530          * We can't copy from userspace directly. Access to
531          * current_driver_name is protected with a write_lock with irqs
532          * disabled. Since copy_from_user can fault and may sleep we
533          * need to copy to temporary buffer first
534          */
535         len = min(count, (size_t)(NAME_MAX_LEN - 1));
536         if (copy_from_user(buf, userbuf, len))
537                 return -EFAULT;
538
539         buf[len] = 0;
540
541         write_lock_irqsave(&driver_name_lock, flags);
542
543         /*
544          * Now handle the string we got from userspace very carefully.
545          * The rules are:
546          *         - only use the first token we got
547          *         - token delimiter is everything looking like a space
548          *           character (' ', '\n', '\t' ...)
549          *
550          */
551         if (!isalnum(buf[0])) {
552                 /*
553                  * If the first character userspace gave us is not
554                  * alphanumerical then assume the filter should be
555                  * switched off.
556                  */
557                 if (current_driver_name[0])
558                         pr_info("DMA-API: switching off dma-debug driver filter\n");
559                 current_driver_name[0] = 0;
560                 current_driver = NULL;
561                 goto out_unlock;
562         }
563
564         /*
565          * Now parse out the first token and use it as the name for the
566          * driver to filter for.
567          */
568         for (i = 0; i < NAME_MAX_LEN; ++i) {
569                 current_driver_name[i] = buf[i];
570                 if (isspace(buf[i]) || buf[i] == ' ' || buf[i] == 0)
571                         break;
572         }
573         current_driver_name[i] = 0;
574         current_driver = NULL;
575
576         pr_info("DMA-API: enable driver filter for driver [%s]\n",
577                 current_driver_name);
578
579 out_unlock:
580         write_unlock_irqrestore(&driver_name_lock, flags);
581
582         return count;
583 }
584
585 const struct file_operations filter_fops = {
586         .read  = filter_read,
587         .write = filter_write,
588 };
589
590 static int dma_debug_fs_init(void)
591 {
592         dma_debug_dent = debugfs_create_dir("dma-api", NULL);
593         if (!dma_debug_dent) {
594                 pr_err("DMA-API: can not create debugfs directory\n");
595                 return -ENOMEM;
596         }
597
598         global_disable_dent = debugfs_create_bool("disabled", 0444,
599                         dma_debug_dent,
600                         (u32 *)&global_disable);
601         if (!global_disable_dent)
602                 goto out_err;
603
604         error_count_dent = debugfs_create_u32("error_count", 0444,
605                         dma_debug_dent, &error_count);
606         if (!error_count_dent)
607                 goto out_err;
608
609         show_all_errors_dent = debugfs_create_u32("all_errors", 0644,
610                         dma_debug_dent,
611                         &show_all_errors);
612         if (!show_all_errors_dent)
613                 goto out_err;
614
615         show_num_errors_dent = debugfs_create_u32("num_errors", 0644,
616                         dma_debug_dent,
617                         &show_num_errors);
618         if (!show_num_errors_dent)
619                 goto out_err;
620
621         num_free_entries_dent = debugfs_create_u32("num_free_entries", 0444,
622                         dma_debug_dent,
623                         &num_free_entries);
624         if (!num_free_entries_dent)
625                 goto out_err;
626
627         min_free_entries_dent = debugfs_create_u32("min_free_entries", 0444,
628                         dma_debug_dent,
629                         &min_free_entries);
630         if (!min_free_entries_dent)
631                 goto out_err;
632
633         filter_dent = debugfs_create_file("driver_filter", 0644,
634                                           dma_debug_dent, NULL, &filter_fops);
635         if (!filter_dent)
636                 goto out_err;
637
638         return 0;
639
640 out_err:
641         debugfs_remove_recursive(dma_debug_dent);
642
643         return -ENOMEM;
644 }
645
646 static int device_dma_allocations(struct device *dev)
647 {
648         struct dma_debug_entry *entry;
649         unsigned long flags;
650         int count = 0, i;
651
652         local_irq_save(flags);
653
654         for (i = 0; i < HASH_SIZE; ++i) {
655                 spin_lock(&dma_entry_hash[i].lock);
656                 list_for_each_entry(entry, &dma_entry_hash[i].list, list) {
657                         if (entry->dev == dev)
658                                 count += 1;
659                 }
660                 spin_unlock(&dma_entry_hash[i].lock);
661         }
662
663         local_irq_restore(flags);
664
665         return count;
666 }
667
668 static int dma_debug_device_change(struct notifier_block *nb,
669                                     unsigned long action, void *data)
670 {
671         struct device *dev = data;
672         int count;
673
674
675         switch (action) {
676         case BUS_NOTIFY_UNBOUND_DRIVER:
677                 count = device_dma_allocations(dev);
678                 if (count == 0)
679                         break;
680                 err_printk(dev, NULL, "DMA-API: device driver has pending "
681                                 "DMA allocations while released from device "
682                                 "[count=%d]\n", count);
683                 break;
684         default:
685                 break;
686         }
687
688         return 0;
689 }
690
691 void dma_debug_add_bus(struct bus_type *bus)
692 {
693         struct notifier_block *nb;
694
695         nb = kzalloc(sizeof(struct notifier_block), GFP_KERNEL);
696         if (nb == NULL) {
697                 pr_err("dma_debug_add_bus: out of memory\n");
698                 return;
699         }
700
701         nb->notifier_call = dma_debug_device_change;
702
703         bus_register_notifier(bus, nb);
704 }
705
706 /*
707  * Let the architectures decide how many entries should be preallocated.
708  */
709 void dma_debug_init(u32 num_entries)
710 {
711         int i;
712
713         if (global_disable)
714                 return;
715
716         for (i = 0; i < HASH_SIZE; ++i) {
717                 INIT_LIST_HEAD(&dma_entry_hash[i].list);
718                 dma_entry_hash[i].lock = SPIN_LOCK_UNLOCKED;
719         }
720
721         if (dma_debug_fs_init() != 0) {
722                 pr_err("DMA-API: error creating debugfs entries - disabling\n");
723                 global_disable = true;
724
725                 return;
726         }
727
728         if (req_entries)
729                 num_entries = req_entries;
730
731         if (prealloc_memory(num_entries) != 0) {
732                 pr_err("DMA-API: debugging out of memory error - disabled\n");
733                 global_disable = true;
734
735                 return;
736         }
737
738         nr_total_entries = num_free_entries;
739
740         pr_info("DMA-API: debugging enabled by kernel config\n");
741 }
742
743 static __init int dma_debug_cmdline(char *str)
744 {
745         if (!str)
746                 return -EINVAL;
747
748         if (strncmp(str, "off", 3) == 0) {
749                 pr_info("DMA-API: debugging disabled on kernel command line\n");
750                 global_disable = true;
751         }
752
753         return 0;
754 }
755
756 static __init int dma_debug_entries_cmdline(char *str)
757 {
758         int res;
759
760         if (!str)
761                 return -EINVAL;
762
763         res = get_option(&str, &req_entries);
764
765         if (!res)
766                 req_entries = 0;
767
768         return 0;
769 }
770
771 __setup("dma_debug=", dma_debug_cmdline);
772 __setup("dma_debug_entries=", dma_debug_entries_cmdline);
773
774 static void check_unmap(struct dma_debug_entry *ref)
775 {
776         struct dma_debug_entry *entry;
777         struct hash_bucket *bucket;
778         unsigned long flags;
779
780         if (dma_mapping_error(ref->dev, ref->dev_addr)) {
781                 err_printk(ref->dev, NULL, "DMA-API: device driver tries "
782                            "to free an invalid DMA memory address\n");
783                 return;
784         }
785
786         bucket = get_hash_bucket(ref, &flags);
787         entry = hash_bucket_find(bucket, ref);
788
789         if (!entry) {
790                 err_printk(ref->dev, NULL, "DMA-API: device driver tries "
791                            "to free DMA memory it has not allocated "
792                            "[device address=0x%016llx] [size=%llu bytes]\n",
793                            ref->dev_addr, ref->size);
794                 goto out;
795         }
796
797         if (ref->size != entry->size) {
798                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
799                            "DMA memory with different size "
800                            "[device address=0x%016llx] [map size=%llu bytes] "
801                            "[unmap size=%llu bytes]\n",
802                            ref->dev_addr, entry->size, ref->size);
803         }
804
805         if (ref->type != entry->type) {
806                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
807                            "DMA memory with wrong function "
808                            "[device address=0x%016llx] [size=%llu bytes] "
809                            "[mapped as %s] [unmapped as %s]\n",
810                            ref->dev_addr, ref->size,
811                            type2name[entry->type], type2name[ref->type]);
812         } else if ((entry->type == dma_debug_coherent) &&
813                    (ref->paddr != entry->paddr)) {
814                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
815                            "DMA memory with different CPU address "
816                            "[device address=0x%016llx] [size=%llu bytes] "
817                            "[cpu alloc address=%p] [cpu free address=%p]",
818                            ref->dev_addr, ref->size,
819                            (void *)entry->paddr, (void *)ref->paddr);
820         }
821
822         if (ref->sg_call_ents && ref->type == dma_debug_sg &&
823             ref->sg_call_ents != entry->sg_call_ents) {
824                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
825                            "DMA sg list with different entry count "
826                            "[map count=%d] [unmap count=%d]\n",
827                            entry->sg_call_ents, ref->sg_call_ents);
828         }
829
830         /*
831          * This may be no bug in reality - but most implementations of the
832          * DMA API don't handle this properly, so check for it here
833          */
834         if (ref->direction != entry->direction) {
835                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
836                            "DMA memory with different direction "
837                            "[device address=0x%016llx] [size=%llu bytes] "
838                            "[mapped with %s] [unmapped with %s]\n",
839                            ref->dev_addr, ref->size,
840                            dir2name[entry->direction],
841                            dir2name[ref->direction]);
842         }
843
844         hash_bucket_del(entry);
845         dma_entry_free(entry);
846
847 out:
848         put_hash_bucket(bucket, &flags);
849 }
850
851 static void check_for_stack(struct device *dev, void *addr)
852 {
853         if (object_is_on_stack(addr))
854                 err_printk(dev, NULL, "DMA-API: device driver maps memory from"
855                                 "stack [addr=%p]\n", addr);
856 }
857
858 static inline bool overlap(void *addr, u64 size, void *start, void *end)
859 {
860         void *addr2 = (char *)addr + size;
861
862         return ((addr >= start && addr < end) ||
863                 (addr2 >= start && addr2 < end) ||
864                 ((addr < start) && (addr2 >= end)));
865 }
866
867 static void check_for_illegal_area(struct device *dev, void *addr, u64 size)
868 {
869         if (overlap(addr, size, _text, _etext) ||
870             overlap(addr, size, __start_rodata, __end_rodata))
871                 err_printk(dev, NULL, "DMA-API: device driver maps "
872                                 "memory from kernel text or rodata "
873                                 "[addr=%p] [size=%llu]\n", addr, size);
874 }
875
876 static void check_sync(struct device *dev, dma_addr_t addr,
877                        u64 size, u64 offset, int direction, bool to_cpu)
878 {
879         struct dma_debug_entry ref = {
880                 .dev            = dev,
881                 .dev_addr       = addr,
882                 .size           = size,
883                 .direction      = direction,
884         };
885         struct dma_debug_entry *entry;
886         struct hash_bucket *bucket;
887         unsigned long flags;
888
889         bucket = get_hash_bucket(&ref, &flags);
890
891         entry = hash_bucket_find(bucket, &ref);
892
893         if (!entry) {
894                 err_printk(dev, NULL, "DMA-API: device driver tries "
895                                 "to sync DMA memory it has not allocated "
896                                 "[device address=0x%016llx] [size=%llu bytes]\n",
897                                 (unsigned long long)addr, size);
898                 goto out;
899         }
900
901         if ((offset + size) > entry->size) {
902                 err_printk(dev, entry, "DMA-API: device driver syncs"
903                                 " DMA memory outside allocated range "
904                                 "[device address=0x%016llx] "
905                                 "[allocation size=%llu bytes] [sync offset=%llu] "
906                                 "[sync size=%llu]\n", entry->dev_addr, entry->size,
907                                 offset, size);
908         }
909
910         if (direction != entry->direction) {
911                 err_printk(dev, entry, "DMA-API: device driver syncs "
912                                 "DMA memory with different direction "
913                                 "[device address=0x%016llx] [size=%llu bytes] "
914                                 "[mapped with %s] [synced with %s]\n",
915                                 (unsigned long long)addr, entry->size,
916                                 dir2name[entry->direction],
917                                 dir2name[direction]);
918         }
919
920         if (entry->direction == DMA_BIDIRECTIONAL)
921                 goto out;
922
923         if (to_cpu && !(entry->direction == DMA_FROM_DEVICE) &&
924                       !(direction == DMA_TO_DEVICE))
925                 err_printk(dev, entry, "DMA-API: device driver syncs "
926                                 "device read-only DMA memory for cpu "
927                                 "[device address=0x%016llx] [size=%llu bytes] "
928                                 "[mapped with %s] [synced with %s]\n",
929                                 (unsigned long long)addr, entry->size,
930                                 dir2name[entry->direction],
931                                 dir2name[direction]);
932
933         if (!to_cpu && !(entry->direction == DMA_TO_DEVICE) &&
934                        !(direction == DMA_FROM_DEVICE))
935                 err_printk(dev, entry, "DMA-API: device driver syncs "
936                                 "device write-only DMA memory to device "
937                                 "[device address=0x%016llx] [size=%llu bytes] "
938                                 "[mapped with %s] [synced with %s]\n",
939                                 (unsigned long long)addr, entry->size,
940                                 dir2name[entry->direction],
941                                 dir2name[direction]);
942
943 out:
944         put_hash_bucket(bucket, &flags);
945
946 }
947
948 void debug_dma_map_page(struct device *dev, struct page *page, size_t offset,
949                         size_t size, int direction, dma_addr_t dma_addr,
950                         bool map_single)
951 {
952         struct dma_debug_entry *entry;
953
954         if (unlikely(global_disable))
955                 return;
956
957         if (unlikely(dma_mapping_error(dev, dma_addr)))
958                 return;
959
960         entry = dma_entry_alloc();
961         if (!entry)
962                 return;
963
964         entry->dev       = dev;
965         entry->type      = dma_debug_page;
966         entry->paddr     = page_to_phys(page) + offset;
967         entry->dev_addr  = dma_addr;
968         entry->size      = size;
969         entry->direction = direction;
970
971         if (map_single)
972                 entry->type = dma_debug_single;
973
974         if (!PageHighMem(page)) {
975                 void *addr = ((char *)page_address(page)) + offset;
976                 check_for_stack(dev, addr);
977                 check_for_illegal_area(dev, addr, size);
978         }
979
980         add_dma_entry(entry);
981 }
982 EXPORT_SYMBOL(debug_dma_map_page);
983
984 void debug_dma_unmap_page(struct device *dev, dma_addr_t addr,
985                           size_t size, int direction, bool map_single)
986 {
987         struct dma_debug_entry ref = {
988                 .type           = dma_debug_page,
989                 .dev            = dev,
990                 .dev_addr       = addr,
991                 .size           = size,
992                 .direction      = direction,
993         };
994
995         if (unlikely(global_disable))
996                 return;
997
998         if (map_single)
999                 ref.type = dma_debug_single;
1000
1001         check_unmap(&ref);
1002 }
1003 EXPORT_SYMBOL(debug_dma_unmap_page);
1004
1005 void debug_dma_map_sg(struct device *dev, struct scatterlist *sg,
1006                       int nents, int mapped_ents, int direction)
1007 {
1008         struct dma_debug_entry *entry;
1009         struct scatterlist *s;
1010         int i;
1011
1012         if (unlikely(global_disable))
1013                 return;
1014
1015         for_each_sg(sg, s, mapped_ents, i) {
1016                 entry = dma_entry_alloc();
1017                 if (!entry)
1018                         return;
1019
1020                 entry->type           = dma_debug_sg;
1021                 entry->dev            = dev;
1022                 entry->paddr          = sg_phys(s);
1023                 entry->size           = sg_dma_len(s);
1024                 entry->dev_addr       = sg_dma_address(s);
1025                 entry->direction      = direction;
1026                 entry->sg_call_ents   = nents;
1027                 entry->sg_mapped_ents = mapped_ents;
1028
1029                 if (!PageHighMem(sg_page(s))) {
1030                         check_for_stack(dev, sg_virt(s));
1031                         check_for_illegal_area(dev, sg_virt(s), sg_dma_len(s));
1032                 }
1033
1034                 add_dma_entry(entry);
1035         }
1036 }
1037 EXPORT_SYMBOL(debug_dma_map_sg);
1038
1039 static int get_nr_mapped_entries(struct device *dev, struct scatterlist *s)
1040 {
1041         struct dma_debug_entry *entry, ref;
1042         struct hash_bucket *bucket;
1043         unsigned long flags;
1044         int mapped_ents;
1045
1046         ref.dev      = dev;
1047         ref.dev_addr = sg_dma_address(s);
1048         ref.size     = sg_dma_len(s),
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   = 0,
1080                 };
1081
1082                 if (mapped_ents && i >= mapped_ents)
1083                         break;
1084
1085                 if (!i) {
1086                         ref.sg_call_ents = nelems;
1087                         mapped_ents = get_nr_mapped_entries(dev, s);
1088                 }
1089
1090                 check_unmap(&ref);
1091         }
1092 }
1093 EXPORT_SYMBOL(debug_dma_unmap_sg);
1094
1095 void debug_dma_alloc_coherent(struct device *dev, size_t size,
1096                               dma_addr_t dma_addr, void *virt)
1097 {
1098         struct dma_debug_entry *entry;
1099
1100         if (unlikely(global_disable))
1101                 return;
1102
1103         if (unlikely(virt == NULL))
1104                 return;
1105
1106         entry = dma_entry_alloc();
1107         if (!entry)
1108                 return;
1109
1110         entry->type      = dma_debug_coherent;
1111         entry->dev       = dev;
1112         entry->paddr     = virt_to_phys(virt);
1113         entry->size      = size;
1114         entry->dev_addr  = dma_addr;
1115         entry->direction = DMA_BIDIRECTIONAL;
1116
1117         add_dma_entry(entry);
1118 }
1119 EXPORT_SYMBOL(debug_dma_alloc_coherent);
1120
1121 void debug_dma_free_coherent(struct device *dev, size_t size,
1122                          void *virt, dma_addr_t addr)
1123 {
1124         struct dma_debug_entry ref = {
1125                 .type           = dma_debug_coherent,
1126                 .dev            = dev,
1127                 .paddr          = virt_to_phys(virt),
1128                 .dev_addr       = addr,
1129                 .size           = size,
1130                 .direction      = DMA_BIDIRECTIONAL,
1131         };
1132
1133         if (unlikely(global_disable))
1134                 return;
1135
1136         check_unmap(&ref);
1137 }
1138 EXPORT_SYMBOL(debug_dma_free_coherent);
1139
1140 void debug_dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_handle,
1141                                    size_t size, int direction)
1142 {
1143         if (unlikely(global_disable))
1144                 return;
1145
1146         check_sync(dev, dma_handle, size, 0, direction, true);
1147 }
1148 EXPORT_SYMBOL(debug_dma_sync_single_for_cpu);
1149
1150 void debug_dma_sync_single_for_device(struct device *dev,
1151                                       dma_addr_t dma_handle, size_t size,
1152                                       int direction)
1153 {
1154         if (unlikely(global_disable))
1155                 return;
1156
1157         check_sync(dev, dma_handle, size, 0, direction, false);
1158 }
1159 EXPORT_SYMBOL(debug_dma_sync_single_for_device);
1160
1161 void debug_dma_sync_single_range_for_cpu(struct device *dev,
1162                                          dma_addr_t dma_handle,
1163                                          unsigned long offset, size_t size,
1164                                          int direction)
1165 {
1166         if (unlikely(global_disable))
1167                 return;
1168
1169         check_sync(dev, dma_handle, size, offset, direction, true);
1170 }
1171 EXPORT_SYMBOL(debug_dma_sync_single_range_for_cpu);
1172
1173 void debug_dma_sync_single_range_for_device(struct device *dev,
1174                                             dma_addr_t dma_handle,
1175                                             unsigned long offset,
1176                                             size_t size, int direction)
1177 {
1178         if (unlikely(global_disable))
1179                 return;
1180
1181         check_sync(dev, dma_handle, size, offset, direction, false);
1182 }
1183 EXPORT_SYMBOL(debug_dma_sync_single_range_for_device);
1184
1185 void debug_dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
1186                                int nelems, int direction)
1187 {
1188         struct scatterlist *s;
1189         int mapped_ents = 0, i;
1190
1191         if (unlikely(global_disable))
1192                 return;
1193
1194         for_each_sg(sg, s, nelems, i) {
1195                 if (!i)
1196                         mapped_ents = get_nr_mapped_entries(dev, s);
1197
1198                 if (i >= mapped_ents)
1199                         break;
1200
1201                 check_sync(dev, sg_dma_address(s), sg_dma_len(s), 0,
1202                            direction, true);
1203         }
1204 }
1205 EXPORT_SYMBOL(debug_dma_sync_sg_for_cpu);
1206
1207 void debug_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
1208                                   int nelems, int direction)
1209 {
1210         struct scatterlist *s;
1211         int mapped_ents = 0, i;
1212
1213         if (unlikely(global_disable))
1214                 return;
1215
1216         for_each_sg(sg, s, nelems, i) {
1217                 if (!i)
1218                         mapped_ents = get_nr_mapped_entries(dev, s);
1219
1220                 if (i >= mapped_ents)
1221                         break;
1222
1223                 check_sync(dev, sg_dma_address(s), sg_dma_len(s), 0,
1224                            direction, false);
1225         }
1226 }
1227 EXPORT_SYMBOL(debug_dma_sync_sg_for_device);
1228
1229 static int __init dma_debug_driver_setup(char *str)
1230 {
1231         int i;
1232
1233         for (i = 0; i < NAME_MAX_LEN - 1; ++i, ++str) {
1234                 current_driver_name[i] = *str;
1235                 if (*str == 0)
1236                         break;
1237         }
1238
1239         if (current_driver_name[0])
1240                 pr_info("DMA-API: enable driver filter for driver [%s]\n",
1241                         current_driver_name);
1242
1243
1244         return 1;
1245 }
1246 __setup("dma_debug_driver=", dma_debug_driver_setup);