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Linux/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/vmalloc.h>
 26 #include <linux/debugfs.h>
 27 #include <linux/uaccess.h>
 28 #include <linux/export.h>
 29 #include <linux/device.h>
 30 #include <linux/types.h>
 31 #include <linux/sched.h>
 32 #include <linux/ctype.h>
 33 #include <linux/list.h>
 34 #include <linux/slab.h>
 35 
 36 #include <asm/sections.h>
 37 
 38 #define HASH_SIZE       1024ULL
 39 #define HASH_FN_SHIFT   13
 40 #define HASH_FN_MASK    (HASH_SIZE - 1)
 41 
 42 enum {
 43         dma_debug_single,
 44         dma_debug_page,
 45         dma_debug_sg,
 46         dma_debug_coherent,
 47         dma_debug_resource,
 48 };
 49 
 50 enum map_err_types {
 51         MAP_ERR_CHECK_NOT_APPLICABLE,
 52         MAP_ERR_NOT_CHECKED,
 53         MAP_ERR_CHECKED,
 54 };
 55 
 56 #define DMA_DEBUG_STACKTRACE_ENTRIES 5
 57 
 58 /**
 59  * struct dma_debug_entry - track a dma_map* or dma_alloc_coherent mapping
 60  * @list: node on pre-allocated free_entries list
 61  * @dev: 'dev' argument to dma_map_{page|single|sg} or dma_alloc_coherent
 62  * @type: single, page, sg, coherent
 63  * @pfn: page frame of the start address
 64  * @offset: offset of mapping relative to pfn
 65  * @size: length of the mapping
 66  * @direction: enum dma_data_direction
 67  * @sg_call_ents: 'nents' from dma_map_sg
 68  * @sg_mapped_ents: 'mapped_ents' from dma_map_sg
 69  * @map_err_type: track whether dma_mapping_error() was checked
 70  * @stacktrace: support backtraces when a violation is detected
 71  */
 72 struct dma_debug_entry {
 73         struct list_head list;
 74         struct device    *dev;
 75         int              type;
 76         unsigned long    pfn;
 77         size_t           offset;
 78         u64              dev_addr;
 79         u64              size;
 80         int              direction;
 81         int              sg_call_ents;
 82         int              sg_mapped_ents;
 83         enum map_err_types  map_err_type;
 84 #ifdef CONFIG_STACKTRACE
 85         struct           stack_trace stacktrace;
 86         unsigned long    st_entries[DMA_DEBUG_STACKTRACE_ENTRIES];
 87 #endif
 88 };
 89 
 90 typedef bool (*match_fn)(struct dma_debug_entry *, struct dma_debug_entry *);
 91 
 92 struct hash_bucket {
 93         struct list_head list;
 94         spinlock_t lock;
 95 } ____cacheline_aligned_in_smp;
 96 
 97 /* Hash list to save the allocated dma addresses */
 98 static struct hash_bucket dma_entry_hash[HASH_SIZE];
 99 /* List of pre-allocated dma_debug_entry's */
100 static LIST_HEAD(free_entries);
101 /* Lock for the list above */
102 static DEFINE_SPINLOCK(free_entries_lock);
103 
104 /* Global disable flag - will be set in case of an error */
105 static bool global_disable __read_mostly;
106 
107 /* Early initialization disable flag, set at the end of dma_debug_init */
108 static bool dma_debug_initialized __read_mostly;
109 
110 static inline bool dma_debug_disabled(void)
111 {
112         return global_disable || !dma_debug_initialized;
113 }
114 
115 /* Global error count */
116 static u32 error_count;
117 
118 /* Global error show enable*/
119 static u32 show_all_errors __read_mostly;
120 /* Number of errors to show */
121 static u32 show_num_errors = 1;
122 
123 static u32 num_free_entries;
124 static u32 min_free_entries;
125 static u32 nr_total_entries;
126 
127 /* number of preallocated entries requested by kernel cmdline */
128 static u32 req_entries;
129 
130 /* debugfs dentry's for the stuff above */
131 static struct dentry *dma_debug_dent        __read_mostly;
132 static struct dentry *global_disable_dent   __read_mostly;
133 static struct dentry *error_count_dent      __read_mostly;
134 static struct dentry *show_all_errors_dent  __read_mostly;
135 static struct dentry *show_num_errors_dent  __read_mostly;
136 static struct dentry *num_free_entries_dent __read_mostly;
137 static struct dentry *min_free_entries_dent __read_mostly;
138 static struct dentry *filter_dent           __read_mostly;
139 
140 /* per-driver filter related state */
141 
142 #define NAME_MAX_LEN    64
143 
144 static char                  current_driver_name[NAME_MAX_LEN] __read_mostly;
145 static struct device_driver *current_driver                    __read_mostly;
146 
147 static DEFINE_RWLOCK(driver_name_lock);
148 
149 static const char *const maperr2str[] = {
150         [MAP_ERR_CHECK_NOT_APPLICABLE] = "dma map error check not applicable",
151         [MAP_ERR_NOT_CHECKED] = "dma map error not checked",
152         [MAP_ERR_CHECKED] = "dma map error checked",
153 };
154 
155 static const char *type2name[5] = { "single", "page",
156                                     "scather-gather", "coherent",
157                                     "resource" };
158 
159 static const char *dir2name[4] = { "DMA_BIDIRECTIONAL", "DMA_TO_DEVICE",
160                                    "DMA_FROM_DEVICE", "DMA_NONE" };
161 
162 /*
163  * The access to some variables in this macro is racy. We can't use atomic_t
164  * here because all these variables are exported to debugfs. Some of them even
165  * writeable. This is also the reason why a lock won't help much. But anyway,
166  * the races are no big deal. Here is why:
167  *
168  *   error_count: the addition is racy, but the worst thing that can happen is
169  *                that we don't count some errors
170  *   show_num_errors: the subtraction is racy. Also no big deal because in
171  *                    worst case this will result in one warning more in the
172  *                    system log than the user configured. This variable is
173  *                    writeable via debugfs.
174  */
175 static inline void dump_entry_trace(struct dma_debug_entry *entry)
176 {
177 #ifdef CONFIG_STACKTRACE
178         if (entry) {
179                 pr_warning("Mapped at:\n");
180                 print_stack_trace(&entry->stacktrace, 0);
181         }
182 #endif
183 }
184 
185 static bool driver_filter(struct device *dev)
186 {
187         struct device_driver *drv;
188         unsigned long flags;
189         bool ret;
190 
191         /* driver filter off */
192         if (likely(!current_driver_name[0]))
193                 return true;
194 
195         /* driver filter on and initialized */
196         if (current_driver && dev && dev->driver == current_driver)
197                 return true;
198 
199         /* driver filter on, but we can't filter on a NULL device... */
200         if (!dev)
201                 return false;
202 
203         if (current_driver || !current_driver_name[0])
204                 return false;
205 
206         /* driver filter on but not yet initialized */
207         drv = dev->driver;
208         if (!drv)
209                 return false;
210 
211         /* lock to protect against change of current_driver_name */
212         read_lock_irqsave(&driver_name_lock, flags);
213 
214         ret = false;
215         if (drv->name &&
216             strncmp(current_driver_name, drv->name, NAME_MAX_LEN - 1) == 0) {
217                 current_driver = drv;
218                 ret = true;
219         }
220 
221         read_unlock_irqrestore(&driver_name_lock, flags);
222 
223         return ret;
224 }
225 
226 #define err_printk(dev, entry, format, arg...) do {                     \
227                 error_count += 1;                                       \
228                 if (driver_filter(dev) &&                               \
229                     (show_all_errors || show_num_errors > 0)) {         \
230                         WARN(1, "%s %s: " format,                       \
231                              dev ? dev_driver_string(dev) : "NULL",     \
232                              dev ? dev_name(dev) : "NULL", ## arg);     \
233                         dump_entry_trace(entry);                        \
234                 }                                                       \
235                 if (!show_all_errors && show_num_errors > 0)            \
236                         show_num_errors -= 1;                           \
237         } while (0);
238 
239 /*
240  * Hash related functions
241  *
242  * Every DMA-API request is saved into a struct dma_debug_entry. To
243  * have quick access to these structs they are stored into a hash.
244  */
245 static int hash_fn(struct dma_debug_entry *entry)
246 {
247         /*
248          * Hash function is based on the dma address.
249          * We use bits 20-27 here as the index into the hash
250          */
251         return (entry->dev_addr >> HASH_FN_SHIFT) & HASH_FN_MASK;
252 }
253 
254 /*
255  * Request exclusive access to a hash bucket for a given dma_debug_entry.
256  */
257 static struct hash_bucket *get_hash_bucket(struct dma_debug_entry *entry,
258                                            unsigned long *flags)
259         __acquires(&dma_entry_hash[idx].lock)
260 {
261         int idx = hash_fn(entry);
262         unsigned long __flags;
263 
264         spin_lock_irqsave(&dma_entry_hash[idx].lock, __flags);
265         *flags = __flags;
266         return &dma_entry_hash[idx];
267 }
268 
269 /*
270  * Give up exclusive access to the hash bucket
271  */
272 static void put_hash_bucket(struct hash_bucket *bucket,
273                             unsigned long *flags)
274         __releases(&bucket->lock)
275 {
276         unsigned long __flags = *flags;
277 
278         spin_unlock_irqrestore(&bucket->lock, __flags);
279 }
280 
281 static bool exact_match(struct dma_debug_entry *a, struct dma_debug_entry *b)
282 {
283         return ((a->dev_addr == b->dev_addr) &&
284                 (a->dev == b->dev)) ? true : false;
285 }
286 
287 static bool containing_match(struct dma_debug_entry *a,
288                              struct dma_debug_entry *b)
289 {
290         if (a->dev != b->dev)
291                 return false;
292 
293         if ((b->dev_addr <= a->dev_addr) &&
294             ((b->dev_addr + b->size) >= (a->dev_addr + a->size)))
295                 return true;
296 
297         return false;
298 }
299 
300 /*
301  * Search a given entry in the hash bucket list
302  */
303 static struct dma_debug_entry *__hash_bucket_find(struct hash_bucket *bucket,
304                                                   struct dma_debug_entry *ref,
305                                                   match_fn match)
306 {
307         struct dma_debug_entry *entry, *ret = NULL;
308         int matches = 0, match_lvl, last_lvl = -1;
309 
310         list_for_each_entry(entry, &bucket->list, list) {
311                 if (!match(ref, entry))
312                         continue;
313 
314                 /*
315                  * Some drivers map the same physical address multiple
316                  * times. Without a hardware IOMMU this results in the
317                  * same device addresses being put into the dma-debug
318                  * hash multiple times too. This can result in false
319                  * positives being reported. Therefore we implement a
320                  * best-fit algorithm here which returns the entry from
321                  * the hash which fits best to the reference value
322                  * instead of the first-fit.
323                  */
324                 matches += 1;
325                 match_lvl = 0;
326                 entry->size         == ref->size         ? ++match_lvl : 0;
327                 entry->type         == ref->type         ? ++match_lvl : 0;
328                 entry->direction    == ref->direction    ? ++match_lvl : 0;
329                 entry->sg_call_ents == ref->sg_call_ents ? ++match_lvl : 0;
330 
331                 if (match_lvl == 4) {
332                         /* perfect-fit - return the result */
333                         return entry;
334                 } else if (match_lvl > last_lvl) {
335                         /*
336                          * We found an entry that fits better then the
337                          * previous one or it is the 1st match.
338                          */
339                         last_lvl = match_lvl;
340                         ret      = entry;
341                 }
342         }
343 
344         /*
345          * If we have multiple matches but no perfect-fit, just return
346          * NULL.
347          */
348         ret = (matches == 1) ? ret : NULL;
349 
350         return ret;
351 }
352 
353 static struct dma_debug_entry *bucket_find_exact(struct hash_bucket *bucket,
354                                                  struct dma_debug_entry *ref)
355 {
356         return __hash_bucket_find(bucket, ref, exact_match);
357 }
358 
359 static struct dma_debug_entry *bucket_find_contain(struct hash_bucket **bucket,
360                                                    struct dma_debug_entry *ref,
361                                                    unsigned long *flags)
362 {
363 
364         unsigned int max_range = dma_get_max_seg_size(ref->dev);
365         struct dma_debug_entry *entry, index = *ref;
366         unsigned int range = 0;
367 
368         while (range <= max_range) {
369                 entry = __hash_bucket_find(*bucket, ref, containing_match);
370 
371                 if (entry)
372                         return entry;
373 
374                 /*
375                  * Nothing found, go back a hash bucket
376                  */
377                 put_hash_bucket(*bucket, flags);
378                 range          += (1 << HASH_FN_SHIFT);
379                 index.dev_addr -= (1 << HASH_FN_SHIFT);
380                 *bucket = get_hash_bucket(&index, flags);
381         }
382 
383         return NULL;
384 }
385 
386 /*
387  * Add an entry to a hash bucket
388  */
389 static void hash_bucket_add(struct hash_bucket *bucket,
390                             struct dma_debug_entry *entry)
391 {
392         list_add_tail(&entry->list, &bucket->list);
393 }
394 
395 /*
396  * Remove entry from a hash bucket list
397  */
398 static void hash_bucket_del(struct dma_debug_entry *entry)
399 {
400         list_del(&entry->list);
401 }
402 
403 static unsigned long long phys_addr(struct dma_debug_entry *entry)
404 {
405         if (entry->type == dma_debug_resource)
406                 return __pfn_to_phys(entry->pfn) + entry->offset;
407 
408         return page_to_phys(pfn_to_page(entry->pfn)) + entry->offset;
409 }
410 
411 /*
412  * Dump mapping entries for debugging purposes
413  */
414 void debug_dma_dump_mappings(struct device *dev)
415 {
416         int idx;
417 
418         for (idx = 0; idx < HASH_SIZE; idx++) {
419                 struct hash_bucket *bucket = &dma_entry_hash[idx];
420                 struct dma_debug_entry *entry;
421                 unsigned long flags;
422 
423                 spin_lock_irqsave(&bucket->lock, flags);
424 
425                 list_for_each_entry(entry, &bucket->list, list) {
426                         if (!dev || dev == entry->dev) {
427                                 dev_info(entry->dev,
428                                          "%s idx %d P=%Lx N=%lx D=%Lx L=%Lx %s %s\n",
429                                          type2name[entry->type], idx,
430                                          phys_addr(entry), entry->pfn,
431                                          entry->dev_addr, entry->size,
432                                          dir2name[entry->direction],
433                                          maperr2str[entry->map_err_type]);
434                         }
435                 }
436 
437                 spin_unlock_irqrestore(&bucket->lock, flags);
438         }
439 }
440 EXPORT_SYMBOL(debug_dma_dump_mappings);
441 
442 /*
443  * For each mapping (initial cacheline in the case of
444  * dma_alloc_coherent/dma_map_page, initial cacheline in each page of a
445  * scatterlist, or the cacheline specified in dma_map_single) insert
446  * into this tree using the cacheline as the key. At
447  * dma_unmap_{single|sg|page} or dma_free_coherent delete the entry.  If
448  * the entry already exists at insertion time add a tag as a reference
449  * count for the overlapping mappings.  For now, the overlap tracking
450  * just ensures that 'unmaps' balance 'maps' before marking the
451  * cacheline idle, but we should also be flagging overlaps as an API
452  * violation.
453  *
454  * Memory usage is mostly constrained by the maximum number of available
455  * dma-debug entries in that we need a free dma_debug_entry before
456  * inserting into the tree.  In the case of dma_map_page and
457  * dma_alloc_coherent there is only one dma_debug_entry and one
458  * dma_active_cacheline entry to track per event.  dma_map_sg(), on the
459  * other hand, consumes a single dma_debug_entry, but inserts 'nents'
460  * entries into the tree.
461  *
462  * At any time debug_dma_assert_idle() can be called to trigger a
463  * warning if any cachelines in the given page are in the active set.
464  */
465 static RADIX_TREE(dma_active_cacheline, GFP_NOWAIT);
466 static DEFINE_SPINLOCK(radix_lock);
467 #define ACTIVE_CACHELINE_MAX_OVERLAP ((1 << RADIX_TREE_MAX_TAGS) - 1)
468 #define CACHELINE_PER_PAGE_SHIFT (PAGE_SHIFT - L1_CACHE_SHIFT)
469 #define CACHELINES_PER_PAGE (1 << CACHELINE_PER_PAGE_SHIFT)
470 
471 static phys_addr_t to_cacheline_number(struct dma_debug_entry *entry)
472 {
473         return (entry->pfn << CACHELINE_PER_PAGE_SHIFT) +
474                 (entry->offset >> L1_CACHE_SHIFT);
475 }
476 
477 static int active_cacheline_read_overlap(phys_addr_t cln)
478 {
479         int overlap = 0, i;
480 
481         for (i = RADIX_TREE_MAX_TAGS - 1; i >= 0; i--)
482                 if (radix_tree_tag_get(&dma_active_cacheline, cln, i))
483                         overlap |= 1 << i;
484         return overlap;
485 }
486 
487 static int active_cacheline_set_overlap(phys_addr_t cln, int overlap)
488 {
489         int i;
490 
491         if (overlap > ACTIVE_CACHELINE_MAX_OVERLAP || overlap < 0)
492                 return overlap;
493 
494         for (i = RADIX_TREE_MAX_TAGS - 1; i >= 0; i--)
495                 if (overlap & 1 << i)
496                         radix_tree_tag_set(&dma_active_cacheline, cln, i);
497                 else
498                         radix_tree_tag_clear(&dma_active_cacheline, cln, i);
499 
500         return overlap;
501 }
502 
503 static void active_cacheline_inc_overlap(phys_addr_t cln)
504 {
505         int overlap = active_cacheline_read_overlap(cln);
506 
507         overlap = active_cacheline_set_overlap(cln, ++overlap);
508 
509         /* If we overflowed the overlap counter then we're potentially
510          * leaking dma-mappings.  Otherwise, if maps and unmaps are
511          * balanced then this overflow may cause false negatives in
512          * debug_dma_assert_idle() as the cacheline may be marked idle
513          * prematurely.
514          */
515         WARN_ONCE(overlap > ACTIVE_CACHELINE_MAX_OVERLAP,
516                   "DMA-API: exceeded %d overlapping mappings of cacheline %pa\n",
517                   ACTIVE_CACHELINE_MAX_OVERLAP, &cln);
518 }
519 
520 static int active_cacheline_dec_overlap(phys_addr_t cln)
521 {
522         int overlap = active_cacheline_read_overlap(cln);
523 
524         return active_cacheline_set_overlap(cln, --overlap);
525 }
526 
527 static int active_cacheline_insert(struct dma_debug_entry *entry)
528 {
529         phys_addr_t cln = to_cacheline_number(entry);
530         unsigned long flags;
531         int rc;
532 
533         /* If the device is not writing memory then we don't have any
534          * concerns about the cpu consuming stale data.  This mitigates
535          * legitimate usages of overlapping mappings.
536          */
537         if (entry->direction == DMA_TO_DEVICE)
538                 return 0;
539 
540         spin_lock_irqsave(&radix_lock, flags);
541         rc = radix_tree_insert(&dma_active_cacheline, cln, entry);
542         if (rc == -EEXIST)
543                 active_cacheline_inc_overlap(cln);
544         spin_unlock_irqrestore(&radix_lock, flags);
545 
546         return rc;
547 }
548 
549 static void active_cacheline_remove(struct dma_debug_entry *entry)
550 {
551         phys_addr_t cln = to_cacheline_number(entry);
552         unsigned long flags;
553 
554         /* ...mirror the insert case */
555         if (entry->direction == DMA_TO_DEVICE)
556                 return;
557 
558         spin_lock_irqsave(&radix_lock, flags);
559         /* since we are counting overlaps the final put of the
560          * cacheline will occur when the overlap count is 0.
561          * active_cacheline_dec_overlap() returns -1 in that case
562          */
563         if (active_cacheline_dec_overlap(cln) < 0)
564                 radix_tree_delete(&dma_active_cacheline, cln);
565         spin_unlock_irqrestore(&radix_lock, flags);
566 }
567 
568 /**
569  * debug_dma_assert_idle() - assert that a page is not undergoing dma
570  * @page: page to lookup in the dma_active_cacheline tree
571  *
572  * Place a call to this routine in cases where the cpu touching the page
573  * before the dma completes (page is dma_unmapped) will lead to data
574  * corruption.
575  */
576 void debug_dma_assert_idle(struct page *page)
577 {
578         static struct dma_debug_entry *ents[CACHELINES_PER_PAGE];
579         struct dma_debug_entry *entry = NULL;
580         void **results = (void **) &ents;
581         unsigned int nents, i;
582         unsigned long flags;
583         phys_addr_t cln;
584 
585         if (dma_debug_disabled())
586                 return;
587 
588         if (!page)
589                 return;
590 
591         cln = (phys_addr_t) page_to_pfn(page) << CACHELINE_PER_PAGE_SHIFT;
592         spin_lock_irqsave(&radix_lock, flags);
593         nents = radix_tree_gang_lookup(&dma_active_cacheline, results, cln,
594                                        CACHELINES_PER_PAGE);
595         for (i = 0; i < nents; i++) {
596                 phys_addr_t ent_cln = to_cacheline_number(ents[i]);
597 
598                 if (ent_cln == cln) {
599                         entry = ents[i];
600                         break;
601                 } else if (ent_cln >= cln + CACHELINES_PER_PAGE)
602                         break;
603         }
604         spin_unlock_irqrestore(&radix_lock, flags);
605 
606         if (!entry)
607                 return;
608 
609         cln = to_cacheline_number(entry);
610         err_printk(entry->dev, entry,
611                    "DMA-API: cpu touching an active dma mapped cacheline [cln=%pa]\n",
612                    &cln);
613 }
614 
615 /*
616  * Wrapper function for adding an entry to the hash.
617  * This function takes care of locking itself.
618  */
619 static void add_dma_entry(struct dma_debug_entry *entry)
620 {
621         struct hash_bucket *bucket;
622         unsigned long flags;
623         int rc;
624 
625         bucket = get_hash_bucket(entry, &flags);
626         hash_bucket_add(bucket, entry);
627         put_hash_bucket(bucket, &flags);
628 
629         rc = active_cacheline_insert(entry);
630         if (rc == -ENOMEM) {
631                 pr_err("DMA-API: cacheline tracking ENOMEM, dma-debug disabled\n");
632                 global_disable = true;
633         }
634 
635         /* TODO: report -EEXIST errors here as overlapping mappings are
636          * not supported by the DMA API
637          */
638 }
639 
640 static struct dma_debug_entry *__dma_entry_alloc(void)
641 {
642         struct dma_debug_entry *entry;
643 
644         entry = list_entry(free_entries.next, struct dma_debug_entry, list);
645         list_del(&entry->list);
646         memset(entry, 0, sizeof(*entry));
647 
648         num_free_entries -= 1;
649         if (num_free_entries < min_free_entries)
650                 min_free_entries = num_free_entries;
651 
652         return entry;
653 }
654 
655 /* struct dma_entry allocator
656  *
657  * The next two functions implement the allocator for
658  * struct dma_debug_entries.
659  */
660 static struct dma_debug_entry *dma_entry_alloc(void)
661 {
662         struct dma_debug_entry *entry;
663         unsigned long flags;
664 
665         spin_lock_irqsave(&free_entries_lock, flags);
666 
667         if (list_empty(&free_entries)) {
668                 global_disable = true;
669                 spin_unlock_irqrestore(&free_entries_lock, flags);
670                 pr_err("DMA-API: debugging out of memory - disabling\n");
671                 return NULL;
672         }
673 
674         entry = __dma_entry_alloc();
675 
676         spin_unlock_irqrestore(&free_entries_lock, flags);
677 
678 #ifdef CONFIG_STACKTRACE
679         entry->stacktrace.max_entries = DMA_DEBUG_STACKTRACE_ENTRIES;
680         entry->stacktrace.entries = entry->st_entries;
681         entry->stacktrace.skip = 2;
682         save_stack_trace(&entry->stacktrace);
683 #endif
684 
685         return entry;
686 }
687 
688 static void dma_entry_free(struct dma_debug_entry *entry)
689 {
690         unsigned long flags;
691 
692         active_cacheline_remove(entry);
693 
694         /*
695          * add to beginning of the list - this way the entries are
696          * more likely cache hot when they are reallocated.
697          */
698         spin_lock_irqsave(&free_entries_lock, flags);
699         list_add(&entry->list, &free_entries);
700         num_free_entries += 1;
701         spin_unlock_irqrestore(&free_entries_lock, flags);
702 }
703 
704 int dma_debug_resize_entries(u32 num_entries)
705 {
706         int i, delta, ret = 0;
707         unsigned long flags;
708         struct dma_debug_entry *entry;
709         LIST_HEAD(tmp);
710 
711         spin_lock_irqsave(&free_entries_lock, flags);
712 
713         if (nr_total_entries < num_entries) {
714                 delta = num_entries - nr_total_entries;
715 
716                 spin_unlock_irqrestore(&free_entries_lock, flags);
717 
718                 for (i = 0; i < delta; i++) {
719                         entry = kzalloc(sizeof(*entry), GFP_KERNEL);
720                         if (!entry)
721                                 break;
722 
723                         list_add_tail(&entry->list, &tmp);
724                 }
725 
726                 spin_lock_irqsave(&free_entries_lock, flags);
727 
728                 list_splice(&tmp, &free_entries);
729                 nr_total_entries += i;
730                 num_free_entries += i;
731         } else {
732                 delta = nr_total_entries - num_entries;
733 
734                 for (i = 0; i < delta && !list_empty(&free_entries); i++) {
735                         entry = __dma_entry_alloc();
736                         kfree(entry);
737                 }
738 
739                 nr_total_entries -= i;
740         }
741 
742         if (nr_total_entries != num_entries)
743                 ret = 1;
744 
745         spin_unlock_irqrestore(&free_entries_lock, flags);
746 
747         return ret;
748 }
749 EXPORT_SYMBOL(dma_debug_resize_entries);
750 
751 /*
752  * DMA-API debugging init code
753  *
754  * The init code does two things:
755  *   1. Initialize core data structures
756  *   2. Preallocate a given number of dma_debug_entry structs
757  */
758 
759 static int prealloc_memory(u32 num_entries)
760 {
761         struct dma_debug_entry *entry, *next_entry;
762         int i;
763 
764         for (i = 0; i < num_entries; ++i) {
765                 entry = kzalloc(sizeof(*entry), GFP_KERNEL);
766                 if (!entry)
767                         goto out_err;
768 
769                 list_add_tail(&entry->list, &free_entries);
770         }
771 
772         num_free_entries = num_entries;
773         min_free_entries = num_entries;
774 
775         pr_info("DMA-API: preallocated %d debug entries\n", num_entries);
776 
777         return 0;
778 
779 out_err:
780 
781         list_for_each_entry_safe(entry, next_entry, &free_entries, list) {
782                 list_del(&entry->list);
783                 kfree(entry);
784         }
785 
786         return -ENOMEM;
787 }
788 
789 static ssize_t filter_read(struct file *file, char __user *user_buf,
790                            size_t count, loff_t *ppos)
791 {
792         char buf[NAME_MAX_LEN + 1];
793         unsigned long flags;
794         int len;
795 
796         if (!current_driver_name[0])
797                 return 0;
798 
799         /*
800          * We can't copy to userspace directly because current_driver_name can
801          * only be read under the driver_name_lock with irqs disabled. So
802          * create a temporary copy first.
803          */
804         read_lock_irqsave(&driver_name_lock, flags);
805         len = scnprintf(buf, NAME_MAX_LEN + 1, "%s\n", current_driver_name);
806         read_unlock_irqrestore(&driver_name_lock, flags);
807 
808         return simple_read_from_buffer(user_buf, count, ppos, buf, len);
809 }
810 
811 static ssize_t filter_write(struct file *file, const char __user *userbuf,
812                             size_t count, loff_t *ppos)
813 {
814         char buf[NAME_MAX_LEN];
815         unsigned long flags;
816         size_t len;
817         int i;
818 
819         /*
820          * We can't copy from userspace directly. Access to
821          * current_driver_name is protected with a write_lock with irqs
822          * disabled. Since copy_from_user can fault and may sleep we
823          * need to copy to temporary buffer first
824          */
825         len = min(count, (size_t)(NAME_MAX_LEN - 1));
826         if (copy_from_user(buf, userbuf, len))
827                 return -EFAULT;
828 
829         buf[len] = 0;
830 
831         write_lock_irqsave(&driver_name_lock, flags);
832 
833         /*
834          * Now handle the string we got from userspace very carefully.
835          * The rules are:
836          *         - only use the first token we got
837          *         - token delimiter is everything looking like a space
838          *           character (' ', '\n', '\t' ...)
839          *
840          */
841         if (!isalnum(buf[0])) {
842                 /*
843                  * If the first character userspace gave us is not
844                  * alphanumerical then assume the filter should be
845                  * switched off.
846                  */
847                 if (current_driver_name[0])
848                         pr_info("DMA-API: switching off dma-debug driver filter\n");
849                 current_driver_name[0] = 0;
850                 current_driver = NULL;
851                 goto out_unlock;
852         }
853 
854         /*
855          * Now parse out the first token and use it as the name for the
856          * driver to filter for.
857          */
858         for (i = 0; i < NAME_MAX_LEN - 1; ++i) {
859                 current_driver_name[i] = buf[i];
860                 if (isspace(buf[i]) || buf[i] == ' ' || buf[i] == 0)
861                         break;
862         }
863         current_driver_name[i] = 0;
864         current_driver = NULL;
865 
866         pr_info("DMA-API: enable driver filter for driver [%s]\n",
867                 current_driver_name);
868 
869 out_unlock:
870         write_unlock_irqrestore(&driver_name_lock, flags);
871 
872         return count;
873 }
874 
875 static const struct file_operations filter_fops = {
876         .read  = filter_read,
877         .write = filter_write,
878         .llseek = default_llseek,
879 };
880 
881 static int dma_debug_fs_init(void)
882 {
883         dma_debug_dent = debugfs_create_dir("dma-api", NULL);
884         if (!dma_debug_dent) {
885                 pr_err("DMA-API: can not create debugfs directory\n");
886                 return -ENOMEM;
887         }
888 
889         global_disable_dent = debugfs_create_bool("disabled", 0444,
890                         dma_debug_dent,
891                         &global_disable);
892         if (!global_disable_dent)
893                 goto out_err;
894 
895         error_count_dent = debugfs_create_u32("error_count", 0444,
896                         dma_debug_dent, &error_count);
897         if (!error_count_dent)
898                 goto out_err;
899 
900         show_all_errors_dent = debugfs_create_u32("all_errors", 0644,
901                         dma_debug_dent,
902                         &show_all_errors);
903         if (!show_all_errors_dent)
904                 goto out_err;
905 
906         show_num_errors_dent = debugfs_create_u32("num_errors", 0644,
907                         dma_debug_dent,
908                         &show_num_errors);
909         if (!show_num_errors_dent)
910                 goto out_err;
911 
912         num_free_entries_dent = debugfs_create_u32("num_free_entries", 0444,
913                         dma_debug_dent,
914                         &num_free_entries);
915         if (!num_free_entries_dent)
916                 goto out_err;
917 
918         min_free_entries_dent = debugfs_create_u32("min_free_entries", 0444,
919                         dma_debug_dent,
920                         &min_free_entries);
921         if (!min_free_entries_dent)
922                 goto out_err;
923 
924         filter_dent = debugfs_create_file("driver_filter", 0644,
925                                           dma_debug_dent, NULL, &filter_fops);
926         if (!filter_dent)
927                 goto out_err;
928 
929         return 0;
930 
931 out_err:
932         debugfs_remove_recursive(dma_debug_dent);
933 
934         return -ENOMEM;
935 }
936 
937 static int device_dma_allocations(struct device *dev, struct dma_debug_entry **out_entry)
938 {
939         struct dma_debug_entry *entry;
940         unsigned long flags;
941         int count = 0, i;
942 
943         local_irq_save(flags);
944 
945         for (i = 0; i < HASH_SIZE; ++i) {
946                 spin_lock(&dma_entry_hash[i].lock);
947                 list_for_each_entry(entry, &dma_entry_hash[i].list, list) {
948                         if (entry->dev == dev) {
949                                 count += 1;
950                                 *out_entry = entry;
951                         }
952                 }
953                 spin_unlock(&dma_entry_hash[i].lock);
954         }
955 
956         local_irq_restore(flags);
957 
958         return count;
959 }
960 
961 static int dma_debug_device_change(struct notifier_block *nb, unsigned long action, void *data)
962 {
963         struct device *dev = data;
964         struct dma_debug_entry *uninitialized_var(entry);
965         int count;
966 
967         if (dma_debug_disabled())
968                 return 0;
969 
970         switch (action) {
971         case BUS_NOTIFY_UNBOUND_DRIVER:
972                 count = device_dma_allocations(dev, &entry);
973                 if (count == 0)
974                         break;
975                 err_printk(dev, entry, "DMA-API: device driver has pending "
976                                 "DMA allocations while released from device "
977                                 "[count=%d]\n"
978                                 "One of leaked entries details: "
979                                 "[device address=0x%016llx] [size=%llu bytes] "
980                                 "[mapped with %s] [mapped as %s]\n",
981                         count, entry->dev_addr, entry->size,
982                         dir2name[entry->direction], type2name[entry->type]);
983                 break;
984         default:
985                 break;
986         }
987 
988         return 0;
989 }
990 
991 void dma_debug_add_bus(struct bus_type *bus)
992 {
993         struct notifier_block *nb;
994 
995         if (dma_debug_disabled())
996                 return;
997 
998         nb = kzalloc(sizeof(struct notifier_block), GFP_KERNEL);
999         if (nb == NULL) {
1000                 pr_err("dma_debug_add_bus: out of memory\n");
1001                 return;
1002         }
1003 
1004         nb->notifier_call = dma_debug_device_change;
1005 
1006         bus_register_notifier(bus, nb);
1007 }
1008 
1009 /*
1010  * Let the architectures decide how many entries should be preallocated.
1011  */
1012 void dma_debug_init(u32 num_entries)
1013 {
1014         int i;
1015 
1016         /* Do not use dma_debug_initialized here, since we really want to be
1017          * called to set dma_debug_initialized
1018          */
1019         if (global_disable)
1020                 return;
1021 
1022         for (i = 0; i < HASH_SIZE; ++i) {
1023                 INIT_LIST_HEAD(&dma_entry_hash[i].list);
1024                 spin_lock_init(&dma_entry_hash[i].lock);
1025         }
1026 
1027         if (dma_debug_fs_init() != 0) {
1028                 pr_err("DMA-API: error creating debugfs entries - disabling\n");
1029                 global_disable = true;
1030 
1031                 return;
1032         }
1033 
1034         if (req_entries)
1035                 num_entries = req_entries;
1036 
1037         if (prealloc_memory(num_entries) != 0) {
1038                 pr_err("DMA-API: debugging out of memory error - disabled\n");
1039                 global_disable = true;
1040 
1041                 return;
1042         }
1043 
1044         nr_total_entries = num_free_entries;
1045 
1046         dma_debug_initialized = true;
1047 
1048         pr_info("DMA-API: debugging enabled by kernel config\n");
1049 }
1050 
1051 static __init int dma_debug_cmdline(char *str)
1052 {
1053         if (!str)
1054                 return -EINVAL;
1055 
1056         if (strncmp(str, "off", 3) == 0) {
1057                 pr_info("DMA-API: debugging disabled on kernel command line\n");
1058                 global_disable = true;
1059         }
1060 
1061         return 0;
1062 }
1063 
1064 static __init int dma_debug_entries_cmdline(char *str)
1065 {
1066         int res;
1067 
1068         if (!str)
1069                 return -EINVAL;
1070 
1071         res = get_option(&str, &req_entries);
1072 
1073         if (!res)
1074                 req_entries = 0;
1075 
1076         return 0;
1077 }
1078 
1079 __setup("dma_debug=", dma_debug_cmdline);
1080 __setup("dma_debug_entries=", dma_debug_entries_cmdline);
1081 
1082 static void check_unmap(struct dma_debug_entry *ref)
1083 {
1084         struct dma_debug_entry *entry;
1085         struct hash_bucket *bucket;
1086         unsigned long flags;
1087 
1088         bucket = get_hash_bucket(ref, &flags);
1089         entry = bucket_find_exact(bucket, ref);
1090 
1091         if (!entry) {
1092                 /* must drop lock before calling dma_mapping_error */
1093                 put_hash_bucket(bucket, &flags);
1094 
1095                 if (dma_mapping_error(ref->dev, ref->dev_addr)) {
1096                         err_printk(ref->dev, NULL,
1097                                    "DMA-API: device driver tries to free an "
1098                                    "invalid DMA memory address\n");
1099                 } else {
1100                         err_printk(ref->dev, NULL,
1101                                    "DMA-API: device driver tries to free DMA "
1102                                    "memory it has not allocated [device "
1103                                    "address=0x%016llx] [size=%llu bytes]\n",
1104                                    ref->dev_addr, ref->size);
1105                 }
1106                 return;
1107         }
1108 
1109         if (ref->size != entry->size) {
1110                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
1111                            "DMA memory with different size "
1112                            "[device address=0x%016llx] [map size=%llu bytes] "
1113                            "[unmap size=%llu bytes]\n",
1114                            ref->dev_addr, entry->size, ref->size);
1115         }
1116 
1117         if (ref->type != entry->type) {
1118                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
1119                            "DMA memory with wrong function "
1120                            "[device address=0x%016llx] [size=%llu bytes] "
1121                            "[mapped as %s] [unmapped as %s]\n",
1122                            ref->dev_addr, ref->size,
1123                            type2name[entry->type], type2name[ref->type]);
1124         } else if ((entry->type == dma_debug_coherent) &&
1125                    (phys_addr(ref) != phys_addr(entry))) {
1126                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
1127                            "DMA memory with different CPU address "
1128                            "[device address=0x%016llx] [size=%llu bytes] "
1129                            "[cpu alloc address=0x%016llx] "
1130                            "[cpu free address=0x%016llx]",
1131                            ref->dev_addr, ref->size,
1132                            phys_addr(entry),
1133                            phys_addr(ref));
1134         }
1135 
1136         if (ref->sg_call_ents && ref->type == dma_debug_sg &&
1137             ref->sg_call_ents != entry->sg_call_ents) {
1138                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
1139                            "DMA sg list with different entry count "
1140                            "[map count=%d] [unmap count=%d]\n",
1141                            entry->sg_call_ents, ref->sg_call_ents);
1142         }
1143 
1144         /*
1145          * This may be no bug in reality - but most implementations of the
1146          * DMA API don't handle this properly, so check for it here
1147          */
1148         if (ref->direction != entry->direction) {
1149                 err_printk(ref->dev, entry, "DMA-API: device driver frees "
1150                            "DMA memory with different direction "
1151                            "[device address=0x%016llx] [size=%llu bytes] "
1152                            "[mapped with %s] [unmapped with %s]\n",
1153                            ref->dev_addr, ref->size,
1154                            dir2name[entry->direction],
1155                            dir2name[ref->direction]);
1156         }
1157 
1158         if (entry->map_err_type == MAP_ERR_NOT_CHECKED) {
1159                 err_printk(ref->dev, entry,
1160                            "DMA-API: device driver failed to check map error"
1161                            "[device address=0x%016llx] [size=%llu bytes] "
1162                            "[mapped as %s]",
1163                            ref->dev_addr, ref->size,
1164                            type2name[entry->type]);
1165         }
1166 
1167         hash_bucket_del(entry);
1168         dma_entry_free(entry);
1169 
1170         put_hash_bucket(bucket, &flags);
1171 }
1172 
1173 static void check_for_stack(struct device *dev,
1174                             struct page *page, size_t offset)
1175 {
1176         void *addr;
1177         struct vm_struct *stack_vm_area = task_stack_vm_area(current);
1178 
1179         if (!stack_vm_area) {
1180                 /* Stack is direct-mapped. */
1181                 if (PageHighMem(page))
1182                         return;
1183                 addr = page_address(page) + offset;
1184                 if (object_is_on_stack(addr))
1185                         err_printk(dev, NULL, "DMA-API: device driver maps memory from stack [addr=%p]\n", addr);
1186         } else {
1187                 /* Stack is vmalloced. */
1188                 int i;
1189 
1190                 for (i = 0; i < stack_vm_area->nr_pages; i++) {
1191                         if (page != stack_vm_area->pages[i])
1192                                 continue;
1193 
1194                         addr = (u8 *)current->stack + i * PAGE_SIZE + offset;
1195                         err_printk(dev, NULL, "DMA-API: device driver maps memory from stack [probable addr=%p]\n", addr);
1196                         break;
1197                 }
1198         }
1199 }
1200 
1201 static inline bool overlap(void *addr, unsigned long len, void *start, void *end)
1202 {
1203         unsigned long a1 = (unsigned long)addr;
1204         unsigned long b1 = a1 + len;
1205         unsigned long a2 = (unsigned long)start;
1206         unsigned long b2 = (unsigned long)end;
1207 
1208         return !(b1 <= a2 || a1 >= b2);
1209 }
1210 
1211 static void check_for_illegal_area(struct device *dev, void *addr, unsigned long len)
1212 {
1213         if (overlap(addr, len, _stext, _etext) ||
1214             overlap(addr, len, __start_rodata, __end_rodata))
1215                 err_printk(dev, NULL, "DMA-API: device driver maps memory from kernel text or rodata [addr=%p] [len=%lu]\n", addr, len);
1216 }
1217 
1218 static void check_sync(struct device *dev,
1219                        struct dma_debug_entry *ref,
1220                        bool to_cpu)
1221 {
1222         struct dma_debug_entry *entry;
1223         struct hash_bucket *bucket;
1224         unsigned long flags;
1225 
1226         bucket = get_hash_bucket(ref, &flags);
1227 
1228         entry = bucket_find_contain(&bucket, ref, &flags);
1229 
1230         if (!entry) {
1231                 err_printk(dev, NULL, "DMA-API: device driver tries "
1232                                 "to sync DMA memory it has not allocated "
1233                                 "[device address=0x%016llx] [size=%llu bytes]\n",
1234                                 (unsigned long long)ref->dev_addr, ref->size);
1235                 goto out;
1236         }
1237 
1238         if (ref->size > entry->size) {
1239                 err_printk(dev, entry, "DMA-API: device driver syncs"
1240                                 " DMA memory outside allocated range "
1241                                 "[device address=0x%016llx] "
1242                                 "[allocation size=%llu bytes] "
1243                                 "[sync offset+size=%llu]\n",
1244                                 entry->dev_addr, entry->size,
1245                                 ref->size);
1246         }
1247 
1248         if (entry->direction == DMA_BIDIRECTIONAL)
1249                 goto out;
1250 
1251         if (ref->direction != entry->direction) {
1252                 err_printk(dev, entry, "DMA-API: device driver syncs "
1253                                 "DMA memory with different direction "
1254                                 "[device address=0x%016llx] [size=%llu bytes] "
1255                                 "[mapped with %s] [synced with %s]\n",
1256                                 (unsigned long long)ref->dev_addr, entry->size,
1257                                 dir2name[entry->direction],
1258                                 dir2name[ref->direction]);
1259         }
1260 
1261         if (to_cpu && !(entry->direction == DMA_FROM_DEVICE) &&
1262                       !(ref->direction == DMA_TO_DEVICE))
1263                 err_printk(dev, entry, "DMA-API: device driver syncs "
1264                                 "device read-only DMA memory for cpu "
1265                                 "[device address=0x%016llx] [size=%llu bytes] "
1266                                 "[mapped with %s] [synced with %s]\n",
1267                                 (unsigned long long)ref->dev_addr, entry->size,
1268                                 dir2name[entry->direction],
1269                                 dir2name[ref->direction]);
1270 
1271         if (!to_cpu && !(entry->direction == DMA_TO_DEVICE) &&
1272                        !(ref->direction == DMA_FROM_DEVICE))
1273                 err_printk(dev, entry, "DMA-API: device driver syncs "
1274                                 "device write-only DMA memory to device "
1275                                 "[device address=0x%016llx] [size=%llu bytes] "
1276                                 "[mapped with %s] [synced with %s]\n",
1277                                 (unsigned long long)ref->dev_addr, entry->size,
1278                                 dir2name[entry->direction],
1279                                 dir2name[ref->direction]);
1280 
1281         if (ref->sg_call_ents && ref->type == dma_debug_sg &&
1282             ref->sg_call_ents != entry->sg_call_ents) {
1283                 err_printk(ref->dev, entry, "DMA-API: device driver syncs "
1284                            "DMA sg list with different entry count "
1285                            "[map count=%d] [sync count=%d]\n",
1286                            entry->sg_call_ents, ref->sg_call_ents);
1287         }
1288 
1289 out:
1290         put_hash_bucket(bucket, &flags);
1291 }
1292 
1293 void debug_dma_map_page(struct device *dev, struct page *page, size_t offset,
1294                         size_t size, int direction, dma_addr_t dma_addr,
1295                         bool map_single)
1296 {
1297         struct dma_debug_entry *entry;
1298 
1299         if (unlikely(dma_debug_disabled()))
1300                 return;
1301 
1302         if (dma_mapping_error(dev, dma_addr))
1303                 return;
1304 
1305         entry = dma_entry_alloc();
1306         if (!entry)
1307                 return;
1308 
1309         entry->dev       = dev;
1310         entry->type      = dma_debug_page;
1311         entry->pfn       = page_to_pfn(page);
1312         entry->offset    = offset,
1313         entry->dev_addr  = dma_addr;
1314         entry->size      = size;
1315         entry->direction = direction;
1316         entry->map_err_type = MAP_ERR_NOT_CHECKED;
1317 
1318         if (map_single)
1319                 entry->type = dma_debug_single;
1320 
1321         check_for_stack(dev, page, offset);
1322 
1323         if (!PageHighMem(page)) {
1324                 void *addr = page_address(page) + offset;
1325 
1326                 check_for_illegal_area(dev, addr, size);
1327         }
1328 
1329         add_dma_entry(entry);
1330 }
1331 EXPORT_SYMBOL(debug_dma_map_page);
1332 
1333 void debug_dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
1334 {
1335         struct dma_debug_entry ref;
1336         struct dma_debug_entry *entry;
1337         struct hash_bucket *bucket;
1338         unsigned long flags;
1339 
1340         if (unlikely(dma_debug_disabled()))
1341                 return;
1342 
1343         ref.dev = dev;
1344         ref.dev_addr = dma_addr;
1345         bucket = get_hash_bucket(&ref, &flags);
1346 
1347         list_for_each_entry(entry, &bucket->list, list) {
1348                 if (!exact_match(&ref, entry))
1349                         continue;
1350 
1351                 /*
1352                  * The same physical address can be mapped multiple
1353                  * times. Without a hardware IOMMU this results in the
1354                  * same device addresses being put into the dma-debug
1355                  * hash multiple times too. This can result in false
1356                  * positives being reported. Therefore we implement a
1357                  * best-fit algorithm here which updates the first entry
1358                  * from the hash which fits the reference value and is
1359                  * not currently listed as being checked.
1360                  */
1361                 if (entry->map_err_type == MAP_ERR_NOT_CHECKED) {
1362                         entry->map_err_type = MAP_ERR_CHECKED;
1363                         break;
1364                 }
1365         }
1366 
1367         put_hash_bucket(bucket, &flags);
1368 }
1369 EXPORT_SYMBOL(debug_dma_mapping_error);
1370 
1371 void debug_dma_unmap_page(struct device *dev, dma_addr_t addr,
1372                           size_t size, int direction, bool map_single)
1373 {
1374         struct dma_debug_entry ref = {
1375                 .type           = dma_debug_page,
1376                 .dev            = dev,
1377                 .dev_addr       = addr,
1378                 .size           = size,
1379                 .direction      = direction,
1380         };
1381 
1382         if (unlikely(dma_debug_disabled()))
1383                 return;
1384 
1385         if (map_single)
1386                 ref.type = dma_debug_single;
1387 
1388         check_unmap(&ref);
1389 }
1390 EXPORT_SYMBOL(debug_dma_unmap_page);
1391 
1392 void debug_dma_map_sg(struct device *dev, struct scatterlist *sg,
1393                       int nents, int mapped_ents, int direction)
1394 {
1395         struct dma_debug_entry *entry;
1396         struct scatterlist *s;
1397         int i;
1398 
1399         if (unlikely(dma_debug_disabled()))
1400                 return;
1401 
1402         for_each_sg(sg, s, mapped_ents, i) {
1403                 entry = dma_entry_alloc();
1404                 if (!entry)
1405                         return;
1406 
1407                 entry->type           = dma_debug_sg;
1408                 entry->dev            = dev;
1409                 entry->pfn            = page_to_pfn(sg_page(s));
1410                 entry->offset         = s->offset,
1411                 entry->size           = sg_dma_len(s);
1412                 entry->dev_addr       = sg_dma_address(s);
1413                 entry->direction      = direction;
1414                 entry->sg_call_ents   = nents;
1415                 entry->sg_mapped_ents = mapped_ents;
1416 
1417                 check_for_stack(dev, sg_page(s), s->offset);
1418 
1419                 if (!PageHighMem(sg_page(s))) {
1420                         check_for_illegal_area(dev, sg_virt(s), sg_dma_len(s));
1421                 }
1422 
1423                 add_dma_entry(entry);
1424         }
1425 }
1426 EXPORT_SYMBOL(debug_dma_map_sg);
1427 
1428 static int get_nr_mapped_entries(struct device *dev,
1429                                  struct dma_debug_entry *ref)
1430 {
1431         struct dma_debug_entry *entry;
1432         struct hash_bucket *bucket;
1433         unsigned long flags;
1434         int mapped_ents;
1435 
1436         bucket       = get_hash_bucket(ref, &flags);
1437         entry        = bucket_find_exact(bucket, ref);
1438         mapped_ents  = 0;
1439 
1440         if (entry)
1441                 mapped_ents = entry->sg_mapped_ents;
1442         put_hash_bucket(bucket, &flags);
1443 
1444         return mapped_ents;
1445 }
1446 
1447 void debug_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
1448                         int nelems, int dir)
1449 {
1450         struct scatterlist *s;
1451         int mapped_ents = 0, i;
1452 
1453         if (unlikely(dma_debug_disabled()))
1454                 return;
1455 
1456         for_each_sg(sglist, s, nelems, i) {
1457 
1458                 struct dma_debug_entry ref = {
1459                         .type           = dma_debug_sg,
1460                         .dev            = dev,
1461                         .pfn            = page_to_pfn(sg_page(s)),
1462                         .offset         = s->offset,
1463                         .dev_addr       = sg_dma_address(s),
1464                         .size           = sg_dma_len(s),
1465                         .direction      = dir,
1466                         .sg_call_ents   = nelems,
1467                 };
1468 
1469                 if (mapped_ents && i >= mapped_ents)
1470                         break;
1471 
1472                 if (!i)
1473                         mapped_ents = get_nr_mapped_entries(dev, &ref);
1474 
1475                 check_unmap(&ref);
1476         }
1477 }
1478 EXPORT_SYMBOL(debug_dma_unmap_sg);
1479 
1480 void debug_dma_alloc_coherent(struct device *dev, size_t size,
1481                               dma_addr_t dma_addr, void *virt)
1482 {
1483         struct dma_debug_entry *entry;
1484 
1485         if (unlikely(dma_debug_disabled()))
1486                 return;
1487 
1488         if (unlikely(virt == NULL))
1489                 return;
1490 
1491         entry = dma_entry_alloc();
1492         if (!entry)
1493                 return;
1494 
1495         entry->type      = dma_debug_coherent;
1496         entry->dev       = dev;
1497         entry->pfn       = page_to_pfn(virt_to_page(virt));
1498         entry->offset    = (size_t) virt & ~PAGE_MASK;
1499         entry->size      = size;
1500         entry->dev_addr  = dma_addr;
1501         entry->direction = DMA_BIDIRECTIONAL;
1502 
1503         add_dma_entry(entry);
1504 }
1505 EXPORT_SYMBOL(debug_dma_alloc_coherent);
1506 
1507 void debug_dma_free_coherent(struct device *dev, size_t size,
1508                          void *virt, dma_addr_t addr)
1509 {
1510         struct dma_debug_entry ref = {
1511                 .type           = dma_debug_coherent,
1512                 .dev            = dev,
1513                 .pfn            = page_to_pfn(virt_to_page(virt)),
1514                 .offset         = (size_t) virt & ~PAGE_MASK,
1515                 .dev_addr       = addr,
1516                 .size           = size,
1517                 .direction      = DMA_BIDIRECTIONAL,
1518         };
1519 
1520         if (unlikely(dma_debug_disabled()))
1521                 return;
1522 
1523         check_unmap(&ref);
1524 }
1525 EXPORT_SYMBOL(debug_dma_free_coherent);
1526 
1527 void debug_dma_map_resource(struct device *dev, phys_addr_t addr, size_t size,
1528                             int direction, dma_addr_t dma_addr)
1529 {
1530         struct dma_debug_entry *entry;
1531 
1532         if (unlikely(dma_debug_disabled()))
1533                 return;
1534 
1535         entry = dma_entry_alloc();
1536         if (!entry)
1537                 return;
1538 
1539         entry->type             = dma_debug_resource;
1540         entry->dev              = dev;
1541         entry->pfn              = PHYS_PFN(addr);
1542         entry->offset           = offset_in_page(addr);
1543         entry->size             = size;
1544         entry->dev_addr         = dma_addr;
1545         entry->direction        = direction;
1546         entry->map_err_type     = MAP_ERR_NOT_CHECKED;
1547 
1548         add_dma_entry(entry);
1549 }
1550 EXPORT_SYMBOL(debug_dma_map_resource);
1551 
1552 void debug_dma_unmap_resource(struct device *dev, dma_addr_t dma_addr,
1553                               size_t size, int direction)
1554 {
1555         struct dma_debug_entry ref = {
1556                 .type           = dma_debug_resource,
1557                 .dev            = dev,
1558                 .dev_addr       = dma_addr,
1559                 .size           = size,
1560                 .direction      = direction,
1561         };
1562 
1563         if (unlikely(dma_debug_disabled()))
1564                 return;
1565 
1566         check_unmap(&ref);
1567 }
1568 EXPORT_SYMBOL(debug_dma_unmap_resource);
1569 
1570 void debug_dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_handle,
1571                                    size_t size, int direction)
1572 {
1573         struct dma_debug_entry ref;
1574 
1575         if (unlikely(dma_debug_disabled()))
1576                 return;
1577 
1578         ref.type         = dma_debug_single;
1579         ref.dev          = dev;
1580         ref.dev_addr     = dma_handle;
1581         ref.size         = size;
1582         ref.direction    = direction;
1583         ref.sg_call_ents = 0;
1584 
1585         check_sync(dev, &ref, true);
1586 }
1587 EXPORT_SYMBOL(debug_dma_sync_single_for_cpu);
1588 
1589 void debug_dma_sync_single_for_device(struct device *dev,
1590                                       dma_addr_t dma_handle, size_t size,
1591                                       int direction)
1592 {
1593         struct dma_debug_entry ref;
1594 
1595         if (unlikely(dma_debug_disabled()))
1596                 return;
1597 
1598         ref.type         = dma_debug_single;
1599         ref.dev          = dev;
1600         ref.dev_addr     = dma_handle;
1601         ref.size         = size;
1602         ref.direction    = direction;
1603         ref.sg_call_ents = 0;
1604 
1605         check_sync(dev, &ref, false);
1606 }
1607 EXPORT_SYMBOL(debug_dma_sync_single_for_device);
1608 
1609 void debug_dma_sync_single_range_for_cpu(struct device *dev,
1610                                          dma_addr_t dma_handle,
1611                                          unsigned long offset, size_t size,
1612                                          int direction)
1613 {
1614         struct dma_debug_entry ref;
1615 
1616         if (unlikely(dma_debug_disabled()))
1617                 return;
1618 
1619         ref.type         = dma_debug_single;
1620         ref.dev          = dev;
1621         ref.dev_addr     = dma_handle;
1622         ref.size         = offset + size;
1623         ref.direction    = direction;
1624         ref.sg_call_ents = 0;
1625 
1626         check_sync(dev, &ref, true);
1627 }
1628 EXPORT_SYMBOL(debug_dma_sync_single_range_for_cpu);
1629 
1630 void debug_dma_sync_single_range_for_device(struct device *dev,
1631                                             dma_addr_t dma_handle,
1632                                             unsigned long offset,
1633                                             size_t size, int direction)
1634 {
1635         struct dma_debug_entry ref;
1636 
1637         if (unlikely(dma_debug_disabled()))
1638                 return;
1639 
1640         ref.type         = dma_debug_single;
1641         ref.dev          = dev;
1642         ref.dev_addr     = dma_handle;
1643         ref.size         = offset + size;
1644         ref.direction    = direction;
1645         ref.sg_call_ents = 0;
1646 
1647         check_sync(dev, &ref, false);
1648 }
1649 EXPORT_SYMBOL(debug_dma_sync_single_range_for_device);
1650 
1651 void debug_dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
1652                                int nelems, int direction)
1653 {
1654         struct scatterlist *s;
1655         int mapped_ents = 0, i;
1656 
1657         if (unlikely(dma_debug_disabled()))
1658                 return;
1659 
1660         for_each_sg(sg, s, nelems, i) {
1661 
1662                 struct dma_debug_entry ref = {
1663                         .type           = dma_debug_sg,
1664                         .dev            = dev,
1665                         .pfn            = page_to_pfn(sg_page(s)),
1666                         .offset         = s->offset,
1667                         .dev_addr       = sg_dma_address(s),
1668                         .size           = sg_dma_len(s),
1669                         .direction      = direction,
1670                         .sg_call_ents   = nelems,
1671                 };
1672 
1673                 if (!i)
1674                         mapped_ents = get_nr_mapped_entries(dev, &ref);
1675 
1676                 if (i >= mapped_ents)
1677                         break;
1678 
1679                 check_sync(dev, &ref, true);
1680         }
1681 }
1682 EXPORT_SYMBOL(debug_dma_sync_sg_for_cpu);
1683 
1684 void debug_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
1685                                   int nelems, int direction)
1686 {
1687         struct scatterlist *s;
1688         int mapped_ents = 0, i;
1689 
1690         if (unlikely(dma_debug_disabled()))
1691                 return;
1692 
1693         for_each_sg(sg, s, nelems, i) {
1694 
1695                 struct dma_debug_entry ref = {
1696                         .type           = dma_debug_sg,
1697                         .dev            = dev,
1698                         .pfn            = page_to_pfn(sg_page(s)),
1699                         .offset         = s->offset,
1700                         .dev_addr       = sg_dma_address(s),
1701                         .size           = sg_dma_len(s),
1702                         .direction      = direction,
1703                         .sg_call_ents   = nelems,
1704                 };
1705                 if (!i)
1706                         mapped_ents = get_nr_mapped_entries(dev, &ref);
1707 
1708                 if (i >= mapped_ents)
1709                         break;
1710 
1711                 check_sync(dev, &ref, false);
1712         }
1713 }
1714 EXPORT_SYMBOL(debug_dma_sync_sg_for_device);
1715 
1716 static int __init dma_debug_driver_setup(char *str)
1717 {
1718         int i;
1719 
1720         for (i = 0; i < NAME_MAX_LEN - 1; ++i, ++str) {
1721                 current_driver_name[i] = *str;
1722                 if (*str == 0)
1723                         break;
1724         }
1725 
1726         if (current_driver_name[0])
1727                 pr_info("DMA-API: enable driver filter for driver [%s]\n",
1728                         current_driver_name);
1729 
1730 
1731         return 1;
1732 }
1733 __setup("dma_debug_driver=", dma_debug_driver_setup);
1734 

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