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TOMOYO Linux Cross Reference
Linux/kernel/dma/debug.c

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  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 #define pr_fmt(fmt)     "DMA-API: " fmt
 21 
 22 #include <linux/sched/task_stack.h>
 23 #include <linux/scatterlist.h>
 24 #include <linux/dma-mapping.h>
 25 #include <linux/sched/task.h>
 26 #include <linux/stacktrace.h>
 27 #include <linux/dma-debug.h>
 28 #include <linux/spinlock.h>
 29 #include <linux/vmalloc.h>
 30 #include <linux/debugfs.h>
 31 #include <linux/uaccess.h>
 32 #include <linux/export.h>
 33 #include <linux/device.h>
 34 #include <linux/types.h>
 35 #include <linux/sched.h>
 36 #include <linux/ctype.h>
 37 #include <linux/list.h>
 38 #include <linux/slab.h>
 39 
 40 #include <asm/sections.h>
 41 
 42 #define HASH_SIZE       1024ULL
 43 #define HASH_FN_SHIFT   13
 44 #define HASH_FN_MASK    (HASH_SIZE - 1)
 45 
 46 #define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16)
 47 /* If the pool runs out, add this many new entries at once */
 48 #define DMA_DEBUG_DYNAMIC_ENTRIES (PAGE_SIZE / sizeof(struct dma_debug_entry))
 49 
 50 enum {
 51         dma_debug_single,
 52         dma_debug_sg,
 53         dma_debug_coherent,
 54         dma_debug_resource,
 55 };
 56 
 57 enum map_err_types {
 58         MAP_ERR_CHECK_NOT_APPLICABLE,
 59         MAP_ERR_NOT_CHECKED,
 60         MAP_ERR_CHECKED,
 61 };
 62 
 63 #define DMA_DEBUG_STACKTRACE_ENTRIES 5
 64 
 65 /**
 66  * struct dma_debug_entry - track a dma_map* or dma_alloc_coherent mapping
 67  * @list: node on pre-allocated free_entries list
 68  * @dev: 'dev' argument to dma_map_{page|single|sg} or dma_alloc_coherent
 69  * @type: single, page, sg, coherent
 70  * @pfn: page frame of the start address
 71  * @offset: offset of mapping relative to pfn
 72  * @size: length of the mapping
 73  * @direction: enum dma_data_direction
 74  * @sg_call_ents: 'nents' from dma_map_sg
 75  * @sg_mapped_ents: 'mapped_ents' from dma_map_sg
 76  * @map_err_type: track whether dma_mapping_error() was checked
 77  * @stacktrace: support backtraces when a violation is detected
 78  */
 79 struct dma_debug_entry {
 80         struct list_head list;
 81         struct device    *dev;
 82         int              type;
 83         unsigned long    pfn;
 84         size_t           offset;
 85         u64              dev_addr;
 86         u64              size;
 87         int              direction;
 88         int              sg_call_ents;
 89         int              sg_mapped_ents;
 90         enum map_err_types  map_err_type;
 91 #ifdef CONFIG_STACKTRACE
 92         struct           stack_trace stacktrace;
 93         unsigned long    st_entries[DMA_DEBUG_STACKTRACE_ENTRIES];
 94 #endif
 95 };
 96 
 97 typedef bool (*match_fn)(struct dma_debug_entry *, struct dma_debug_entry *);
 98 
 99 struct hash_bucket {
100         struct list_head list;
101         spinlock_t lock;
102 } ____cacheline_aligned_in_smp;
103 
104 /* Hash list to save the allocated dma addresses */
105 static struct hash_bucket dma_entry_hash[HASH_SIZE];
106 /* List of pre-allocated dma_debug_entry's */
107 static LIST_HEAD(free_entries);
108 /* Lock for the list above */
109 static DEFINE_SPINLOCK(free_entries_lock);
110 
111 /* Global disable flag - will be set in case of an error */
112 static bool global_disable __read_mostly;
113 
114 /* Early initialization disable flag, set at the end of dma_debug_init */
115 static bool dma_debug_initialized __read_mostly;
116 
117 static inline bool dma_debug_disabled(void)
118 {
119         return global_disable || !dma_debug_initialized;
120 }
121 
122 /* Global error count */
123 static u32 error_count;
124 
125 /* Global error show enable*/
126 static u32 show_all_errors __read_mostly;
127 /* Number of errors to show */
128 static u32 show_num_errors = 1;
129 
130 static u32 num_free_entries;
131 static u32 min_free_entries;
132 static u32 nr_total_entries;
133 
134 /* number of preallocated entries requested by kernel cmdline */
135 static u32 nr_prealloc_entries = PREALLOC_DMA_DEBUG_ENTRIES;
136 
137 /* per-driver filter related state */
138 
139 #define NAME_MAX_LEN    64
140 
141 static char                  current_driver_name[NAME_MAX_LEN] __read_mostly;
142 static struct device_driver *current_driver                    __read_mostly;
143 
144 static DEFINE_RWLOCK(driver_name_lock);
145 
146 static const char *const maperr2str[] = {
147         [MAP_ERR_CHECK_NOT_APPLICABLE] = "dma map error check not applicable",
148         [MAP_ERR_NOT_CHECKED] = "dma map error not checked",
149         [MAP_ERR_CHECKED] = "dma map error checked",
150 };
151 
152 static const char *type2name[5] = { "single", "page",
153                                     "scather-gather", "coherent",
154                                     "resource" };
155 
156 static const char *dir2name[4] = { "DMA_BIDIRECTIONAL", "DMA_TO_DEVICE",
157                                    "DMA_FROM_DEVICE", "DMA_NONE" };
158 
159 /*
160  * The access to some variables in this macro is racy. We can't use atomic_t
161  * here because all these variables are exported to debugfs. Some of them even
162  * writeable. This is also the reason why a lock won't help much. But anyway,
163  * the races are no big deal. Here is why:
164  *
165  *   error_count: the addition is racy, but the worst thing that can happen is
166  *                that we don't count some errors
167  *   show_num_errors: the subtraction is racy. Also no big deal because in
168  *                    worst case this will result in one warning more in the
169  *                    system log than the user configured. This variable is
170  *                    writeable via debugfs.
171  */
172 static inline void dump_entry_trace(struct dma_debug_entry *entry)
173 {
174 #ifdef CONFIG_STACKTRACE
175         if (entry) {
176                 pr_warning("Mapped at:\n");
177                 print_stack_trace(&entry->stacktrace, 0);
178         }
179 #endif
180 }
181 
182 static bool driver_filter(struct device *dev)
183 {
184         struct device_driver *drv;
185         unsigned long flags;
186         bool ret;
187 
188         /* driver filter off */
189         if (likely(!current_driver_name[0]))
190                 return true;
191 
192         /* driver filter on and initialized */
193         if (current_driver && dev && dev->driver == current_driver)
194                 return true;
195 
196         /* driver filter on, but we can't filter on a NULL device... */
197         if (!dev)
198                 return false;
199 
200         if (current_driver || !current_driver_name[0])
201                 return false;
202 
203         /* driver filter on but not yet initialized */
204         drv = dev->driver;
205         if (!drv)
206                 return false;
207 
208         /* lock to protect against change of current_driver_name */
209         read_lock_irqsave(&driver_name_lock, flags);
210 
211         ret = false;
212         if (drv->name &&
213             strncmp(current_driver_name, drv->name, NAME_MAX_LEN - 1) == 0) {
214                 current_driver = drv;
215                 ret = true;
216         }
217 
218         read_unlock_irqrestore(&driver_name_lock, flags);
219 
220         return ret;
221 }
222 
223 #define err_printk(dev, entry, format, arg...) do {                     \
224                 error_count += 1;                                       \
225                 if (driver_filter(dev) &&                               \
226                     (show_all_errors || show_num_errors > 0)) {         \
227                         WARN(1, pr_fmt("%s %s: ") format,               \
228                              dev ? dev_driver_string(dev) : "NULL",     \
229                              dev ? dev_name(dev) : "NULL", ## arg);     \
230                         dump_entry_trace(entry);                        \
231                 }                                                       \
232                 if (!show_all_errors && show_num_errors > 0)            \
233                         show_num_errors -= 1;                           \
234         } while (0);
235 
236 /*
237  * Hash related functions
238  *
239  * Every DMA-API request is saved into a struct dma_debug_entry. To
240  * have quick access to these structs they are stored into a hash.
241  */
242 static int hash_fn(struct dma_debug_entry *entry)
243 {
244         /*
245          * Hash function is based on the dma address.
246          * We use bits 20-27 here as the index into the hash
247          */
248         return (entry->dev_addr >> HASH_FN_SHIFT) & HASH_FN_MASK;
249 }
250 
251 /*
252  * Request exclusive access to a hash bucket for a given dma_debug_entry.
253  */
254 static struct hash_bucket *get_hash_bucket(struct dma_debug_entry *entry,
255                                            unsigned long *flags)
256         __acquires(&dma_entry_hash[idx].lock)
257 {
258         int idx = hash_fn(entry);
259         unsigned long __flags;
260 
261         spin_lock_irqsave(&dma_entry_hash[idx].lock, __flags);
262         *flags = __flags;
263         return &dma_entry_hash[idx];
264 }
265 
266 /*
267  * Give up exclusive access to the hash bucket
268  */
269 static void put_hash_bucket(struct hash_bucket *bucket,
270                             unsigned long *flags)
271         __releases(&bucket->lock)
272 {
273         unsigned long __flags = *flags;
274 
275         spin_unlock_irqrestore(&bucket->lock, __flags);
276 }
277 
278 static bool exact_match(struct dma_debug_entry *a, struct dma_debug_entry *b)
279 {
280         return ((a->dev_addr == b->dev_addr) &&
281                 (a->dev == b->dev)) ? true : false;
282 }
283 
284 static bool containing_match(struct dma_debug_entry *a,
285                              struct dma_debug_entry *b)
286 {
287         if (a->dev != b->dev)
288                 return false;
289 
290         if ((b->dev_addr <= a->dev_addr) &&
291             ((b->dev_addr + b->size) >= (a->dev_addr + a->size)))
292                 return true;
293 
294         return false;
295 }
296 
297 /*
298  * Search a given entry in the hash bucket list
299  */
300 static struct dma_debug_entry *__hash_bucket_find(struct hash_bucket *bucket,
301                                                   struct dma_debug_entry *ref,
302                                                   match_fn match)
303 {
304         struct dma_debug_entry *entry, *ret = NULL;
305         int matches = 0, match_lvl, last_lvl = -1;
306 
307         list_for_each_entry(entry, &bucket->list, list) {
308                 if (!match(ref, entry))
309                         continue;
310 
311                 /*
312                  * Some drivers map the same physical address multiple
313                  * times. Without a hardware IOMMU this results in the
314                  * same device addresses being put into the dma-debug
315                  * hash multiple times too. This can result in false
316                  * positives being reported. Therefore we implement a
317                  * best-fit algorithm here which returns the entry from
318                  * the hash which fits best to the reference value
319                  * instead of the first-fit.
320                  */
321                 matches += 1;
322                 match_lvl = 0;
323                 entry->size         == ref->size         ? ++match_lvl : 0;
324                 entry->type         == ref->type         ? ++match_lvl : 0;
325                 entry->direction    == ref->direction    ? ++match_lvl : 0;
326                 entry->sg_call_ents == ref->sg_call_ents ? ++match_lvl : 0;
327 
328                 if (match_lvl == 4) {
329                         /* perfect-fit - return the result */
330                         return entry;
331                 } else if (match_lvl > last_lvl) {
332                         /*
333                          * We found an entry that fits better then the
334                          * previous one or it is the 1st match.
335                          */
336                         last_lvl = match_lvl;
337                         ret      = entry;
338                 }
339         }
340 
341         /*
342          * If we have multiple matches but no perfect-fit, just return
343          * NULL.
344          */
345         ret = (matches == 1) ? ret : NULL;
346 
347         return ret;
348 }
349 
350 static struct dma_debug_entry *bucket_find_exact(struct hash_bucket *bucket,
351                                                  struct dma_debug_entry *ref)
352 {
353         return __hash_bucket_find(bucket, ref, exact_match);
354 }
355 
356 static struct dma_debug_entry *bucket_find_contain(struct hash_bucket **bucket,
357                                                    struct dma_debug_entry *ref,
358                                                    unsigned long *flags)
359 {
360 
361         unsigned int max_range = dma_get_max_seg_size(ref->dev);
362         struct dma_debug_entry *entry, index = *ref;
363         unsigned int range = 0;
364 
365         while (range <= max_range) {
366                 entry = __hash_bucket_find(*bucket, ref, containing_match);
367 
368                 if (entry)
369                         return entry;
370 
371                 /*
372                  * Nothing found, go back a hash bucket
373                  */
374                 put_hash_bucket(*bucket, flags);
375                 range          += (1 << HASH_FN_SHIFT);
376                 index.dev_addr -= (1 << HASH_FN_SHIFT);
377                 *bucket = get_hash_bucket(&index, flags);
378         }
379 
380         return NULL;
381 }
382 
383 /*
384  * Add an entry to a hash bucket
385  */
386 static void hash_bucket_add(struct hash_bucket *bucket,
387                             struct dma_debug_entry *entry)
388 {
389         list_add_tail(&entry->list, &bucket->list);
390 }
391 
392 /*
393  * Remove entry from a hash bucket list
394  */
395 static void hash_bucket_del(struct dma_debug_entry *entry)
396 {
397         list_del(&entry->list);
398 }
399 
400 static unsigned long long phys_addr(struct dma_debug_entry *entry)
401 {
402         if (entry->type == dma_debug_resource)
403                 return __pfn_to_phys(entry->pfn) + entry->offset;
404 
405         return page_to_phys(pfn_to_page(entry->pfn)) + entry->offset;
406 }
407 
408 /*
409  * Dump mapping entries for debugging purposes
410  */
411 void debug_dma_dump_mappings(struct device *dev)
412 {
413         int idx;
414 
415         for (idx = 0; idx < HASH_SIZE; idx++) {
416                 struct hash_bucket *bucket = &dma_entry_hash[idx];
417                 struct dma_debug_entry *entry;
418                 unsigned long flags;
419 
420                 spin_lock_irqsave(&bucket->lock, flags);
421 
422                 list_for_each_entry(entry, &bucket->list, list) {
423                         if (!dev || dev == entry->dev) {
424                                 dev_info(entry->dev,
425                                          "%s idx %d P=%Lx N=%lx D=%Lx L=%Lx %s %s\n",
426                                          type2name[entry->type], idx,
427                                          phys_addr(entry), entry->pfn,
428                                          entry->dev_addr, entry->size,
429                                          dir2name[entry->direction],
430                                          maperr2str[entry->map_err_type]);
431                         }
432                 }
433 
434                 spin_unlock_irqrestore(&bucket->lock, flags);
435         }
436 }
437 
438 /*
439  * For each mapping (initial cacheline in the case of
440  * dma_alloc_coherent/dma_map_page, initial cacheline in each page of a
441  * scatterlist, or the cacheline specified in dma_map_single) insert
442  * into this tree using the cacheline as the key. At
443  * dma_unmap_{single|sg|page} or dma_free_coherent delete the entry.  If
444  * the entry already exists at insertion time add a tag as a reference
445  * count for the overlapping mappings.  For now, the overlap tracking
446  * just ensures that 'unmaps' balance 'maps' before marking the
447  * cacheline idle, but we should also be flagging overlaps as an API
448  * violation.
449  *
450  * Memory usage is mostly constrained by the maximum number of available
451  * dma-debug entries in that we need a free dma_debug_entry before
452  * inserting into the tree.  In the case of dma_map_page and
453  * dma_alloc_coherent there is only one dma_debug_entry and one
454  * dma_active_cacheline entry to track per event.  dma_map_sg(), on the
455  * other hand, consumes a single dma_debug_entry, but inserts 'nents'
456  * entries into the tree.
457  *
458  * At any time debug_dma_assert_idle() can be called to trigger a
459  * warning if any cachelines in the given page are in the active set.
460  */
461 static RADIX_TREE(dma_active_cacheline, GFP_NOWAIT);
462 static DEFINE_SPINLOCK(radix_lock);
463 #define ACTIVE_CACHELINE_MAX_OVERLAP ((1 << RADIX_TREE_MAX_TAGS) - 1)
464 #define CACHELINE_PER_PAGE_SHIFT (PAGE_SHIFT - L1_CACHE_SHIFT)
465 #define CACHELINES_PER_PAGE (1 << CACHELINE_PER_PAGE_SHIFT)
466 
467 static phys_addr_t to_cacheline_number(struct dma_debug_entry *entry)
468 {
469         return (entry->pfn << CACHELINE_PER_PAGE_SHIFT) +
470                 (entry->offset >> L1_CACHE_SHIFT);
471 }
472 
473 static int active_cacheline_read_overlap(phys_addr_t cln)
474 {
475         int overlap = 0, i;
476 
477         for (i = RADIX_TREE_MAX_TAGS - 1; i >= 0; i--)
478                 if (radix_tree_tag_get(&dma_active_cacheline, cln, i))
479                         overlap |= 1 << i;
480         return overlap;
481 }
482 
483 static int active_cacheline_set_overlap(phys_addr_t cln, int overlap)
484 {
485         int i;
486 
487         if (overlap > ACTIVE_CACHELINE_MAX_OVERLAP || overlap < 0)
488                 return overlap;
489 
490         for (i = RADIX_TREE_MAX_TAGS - 1; i >= 0; i--)
491                 if (overlap & 1 << i)
492                         radix_tree_tag_set(&dma_active_cacheline, cln, i);
493                 else
494                         radix_tree_tag_clear(&dma_active_cacheline, cln, i);
495 
496         return overlap;
497 }
498 
499 static void active_cacheline_inc_overlap(phys_addr_t cln)
500 {
501         int overlap = active_cacheline_read_overlap(cln);
502 
503         overlap = active_cacheline_set_overlap(cln, ++overlap);
504 
505         /* If we overflowed the overlap counter then we're potentially
506          * leaking dma-mappings.  Otherwise, if maps and unmaps are
507          * balanced then this overflow may cause false negatives in
508          * debug_dma_assert_idle() as the cacheline may be marked idle
509          * prematurely.
510          */
511         WARN_ONCE(overlap > ACTIVE_CACHELINE_MAX_OVERLAP,
512                   pr_fmt("exceeded %d overlapping mappings of cacheline %pa\n"),
513                   ACTIVE_CACHELINE_MAX_OVERLAP, &cln);
514 }
515 
516 static int active_cacheline_dec_overlap(phys_addr_t cln)
517 {
518         int overlap = active_cacheline_read_overlap(cln);
519 
520         return active_cacheline_set_overlap(cln, --overlap);
521 }
522 
523 static int active_cacheline_insert(struct dma_debug_entry *entry)
524 {
525         phys_addr_t cln = to_cacheline_number(entry);
526         unsigned long flags;
527         int rc;
528 
529         /* If the device is not writing memory then we don't have any
530          * concerns about the cpu consuming stale data.  This mitigates
531          * legitimate usages of overlapping mappings.
532          */
533         if (entry->direction == DMA_TO_DEVICE)
534                 return 0;
535 
536         spin_lock_irqsave(&radix_lock, flags);
537         rc = radix_tree_insert(&dma_active_cacheline, cln, entry);
538         if (rc == -EEXIST)
539                 active_cacheline_inc_overlap(cln);
540         spin_unlock_irqrestore(&radix_lock, flags);
541 
542         return rc;
543 }
544 
545 static void active_cacheline_remove(struct dma_debug_entry *entry)
546 {
547         phys_addr_t cln = to_cacheline_number(entry);
548         unsigned long flags;
549 
550         /* ...mirror the insert case */
551         if (entry->direction == DMA_TO_DEVICE)
552                 return;
553 
554         spin_lock_irqsave(&radix_lock, flags);
555         /* since we are counting overlaps the final put of the
556          * cacheline will occur when the overlap count is 0.
557          * active_cacheline_dec_overlap() returns -1 in that case
558          */
559         if (active_cacheline_dec_overlap(cln) < 0)
560                 radix_tree_delete(&dma_active_cacheline, cln);
561         spin_unlock_irqrestore(&radix_lock, flags);
562 }
563 
564 /**
565  * debug_dma_assert_idle() - assert that a page is not undergoing dma
566  * @page: page to lookup in the dma_active_cacheline tree
567  *
568  * Place a call to this routine in cases where the cpu touching the page
569  * before the dma completes (page is dma_unmapped) will lead to data
570  * corruption.
571  */
572 void debug_dma_assert_idle(struct page *page)
573 {
574         static struct dma_debug_entry *ents[CACHELINES_PER_PAGE];
575         struct dma_debug_entry *entry = NULL;
576         void **results = (void **) &ents;
577         unsigned int nents, i;
578         unsigned long flags;
579         phys_addr_t cln;
580 
581         if (dma_debug_disabled())
582                 return;
583 
584         if (!page)
585                 return;
586 
587         cln = (phys_addr_t) page_to_pfn(page) << CACHELINE_PER_PAGE_SHIFT;
588         spin_lock_irqsave(&radix_lock, flags);
589         nents = radix_tree_gang_lookup(&dma_active_cacheline, results, cln,
590                                        CACHELINES_PER_PAGE);
591         for (i = 0; i < nents; i++) {
592                 phys_addr_t ent_cln = to_cacheline_number(ents[i]);
593 
594                 if (ent_cln == cln) {
595                         entry = ents[i];
596                         break;
597                 } else if (ent_cln >= cln + CACHELINES_PER_PAGE)
598                         break;
599         }
600         spin_unlock_irqrestore(&radix_lock, flags);
601 
602         if (!entry)
603                 return;
604 
605         cln = to_cacheline_number(entry);
606         err_printk(entry->dev, entry,
607                    "cpu touching an active dma mapped cacheline [cln=%pa]\n",
608                    &cln);
609 }
610 
611 /*
612  * Wrapper function for adding an entry to the hash.
613  * This function takes care of locking itself.
614  */
615 static void add_dma_entry(struct dma_debug_entry *entry)
616 {
617         struct hash_bucket *bucket;
618         unsigned long flags;
619         int rc;
620 
621         bucket = get_hash_bucket(entry, &flags);
622         hash_bucket_add(bucket, entry);
623         put_hash_bucket(bucket, &flags);
624 
625         rc = active_cacheline_insert(entry);
626         if (rc == -ENOMEM) {
627                 pr_err("cacheline tracking ENOMEM, dma-debug disabled\n");
628                 global_disable = true;
629         }
630 
631         /* TODO: report -EEXIST errors here as overlapping mappings are
632          * not supported by the DMA API
633          */
634 }
635 
636 static int dma_debug_create_entries(gfp_t gfp)
637 {
638         struct dma_debug_entry *entry;
639         int i;
640 
641         entry = (void *)get_zeroed_page(gfp);
642         if (!entry)
643                 return -ENOMEM;
644 
645         for (i = 0; i < DMA_DEBUG_DYNAMIC_ENTRIES; i++)
646                 list_add_tail(&entry[i].list, &free_entries);
647 
648         num_free_entries += DMA_DEBUG_DYNAMIC_ENTRIES;
649         nr_total_entries += DMA_DEBUG_DYNAMIC_ENTRIES;
650 
651         return 0;
652 }
653 
654 static struct dma_debug_entry *__dma_entry_alloc(void)
655 {
656         struct dma_debug_entry *entry;
657 
658         entry = list_entry(free_entries.next, struct dma_debug_entry, list);
659         list_del(&entry->list);
660         memset(entry, 0, sizeof(*entry));
661 
662         num_free_entries -= 1;
663         if (num_free_entries < min_free_entries)
664                 min_free_entries = num_free_entries;
665 
666         return entry;
667 }
668 
669 void __dma_entry_alloc_check_leak(void)
670 {
671         u32 tmp = nr_total_entries % nr_prealloc_entries;
672 
673         /* Shout each time we tick over some multiple of the initial pool */
674         if (tmp < DMA_DEBUG_DYNAMIC_ENTRIES) {
675                 pr_info("dma_debug_entry pool grown to %u (%u00%%)\n",
676                         nr_total_entries,
677                         (nr_total_entries / nr_prealloc_entries));
678         }
679 }
680 
681 /* struct dma_entry allocator
682  *
683  * The next two functions implement the allocator for
684  * struct dma_debug_entries.
685  */
686 static struct dma_debug_entry *dma_entry_alloc(void)
687 {
688         struct dma_debug_entry *entry;
689         unsigned long flags;
690 
691         spin_lock_irqsave(&free_entries_lock, flags);
692         if (num_free_entries == 0) {
693                 if (dma_debug_create_entries(GFP_ATOMIC)) {
694                         global_disable = true;
695                         spin_unlock_irqrestore(&free_entries_lock, flags);
696                         pr_err("debugging out of memory - disabling\n");
697                         return NULL;
698                 }
699                 __dma_entry_alloc_check_leak();
700         }
701 
702         entry = __dma_entry_alloc();
703 
704         spin_unlock_irqrestore(&free_entries_lock, flags);
705 
706 #ifdef CONFIG_STACKTRACE
707         entry->stacktrace.max_entries = DMA_DEBUG_STACKTRACE_ENTRIES;
708         entry->stacktrace.entries = entry->st_entries;
709         entry->stacktrace.skip = 1;
710         save_stack_trace(&entry->stacktrace);
711 #endif
712 
713         return entry;
714 }
715 
716 static void dma_entry_free(struct dma_debug_entry *entry)
717 {
718         unsigned long flags;
719 
720         active_cacheline_remove(entry);
721 
722         /*
723          * add to beginning of the list - this way the entries are
724          * more likely cache hot when they are reallocated.
725          */
726         spin_lock_irqsave(&free_entries_lock, flags);
727         list_add(&entry->list, &free_entries);
728         num_free_entries += 1;
729         spin_unlock_irqrestore(&free_entries_lock, flags);
730 }
731 
732 /*
733  * DMA-API debugging init code
734  *
735  * The init code does two things:
736  *   1. Initialize core data structures
737  *   2. Preallocate a given number of dma_debug_entry structs
738  */
739 
740 static ssize_t filter_read(struct file *file, char __user *user_buf,
741                            size_t count, loff_t *ppos)
742 {
743         char buf[NAME_MAX_LEN + 1];
744         unsigned long flags;
745         int len;
746 
747         if (!current_driver_name[0])
748                 return 0;
749 
750         /*
751          * We can't copy to userspace directly because current_driver_name can
752          * only be read under the driver_name_lock with irqs disabled. So
753          * create a temporary copy first.
754          */
755         read_lock_irqsave(&driver_name_lock, flags);
756         len = scnprintf(buf, NAME_MAX_LEN + 1, "%s\n", current_driver_name);
757         read_unlock_irqrestore(&driver_name_lock, flags);
758 
759         return simple_read_from_buffer(user_buf, count, ppos, buf, len);
760 }
761 
762 static ssize_t filter_write(struct file *file, const char __user *userbuf,
763                             size_t count, loff_t *ppos)
764 {
765         char buf[NAME_MAX_LEN];
766         unsigned long flags;
767         size_t len;
768         int i;
769 
770         /*
771          * We can't copy from userspace directly. Access to
772          * current_driver_name is protected with a write_lock with irqs
773          * disabled. Since copy_from_user can fault and may sleep we
774          * need to copy to temporary buffer first
775          */
776         len = min(count, (size_t)(NAME_MAX_LEN - 1));
777         if (copy_from_user(buf, userbuf, len))
778                 return -EFAULT;
779 
780         buf[len] = 0;
781 
782         write_lock_irqsave(&driver_name_lock, flags);
783 
784         /*
785          * Now handle the string we got from userspace very carefully.
786          * The rules are:
787          *         - only use the first token we got
788          *         - token delimiter is everything looking like a space
789          *           character (' ', '\n', '\t' ...)
790          *
791          */
792         if (!isalnum(buf[0])) {
793                 /*
794                  * If the first character userspace gave us is not
795                  * alphanumerical then assume the filter should be
796                  * switched off.
797                  */
798                 if (current_driver_name[0])
799                         pr_info("switching off dma-debug driver filter\n");
800                 current_driver_name[0] = 0;
801                 current_driver = NULL;
802                 goto out_unlock;
803         }
804 
805         /*
806          * Now parse out the first token and use it as the name for the
807          * driver to filter for.
808          */
809         for (i = 0; i < NAME_MAX_LEN - 1; ++i) {
810                 current_driver_name[i] = buf[i];
811                 if (isspace(buf[i]) || buf[i] == ' ' || buf[i] == 0)
812                         break;
813         }
814         current_driver_name[i] = 0;
815         current_driver = NULL;
816 
817         pr_info("enable driver filter for driver [%s]\n",
818                 current_driver_name);
819 
820 out_unlock:
821         write_unlock_irqrestore(&driver_name_lock, flags);
822 
823         return count;
824 }
825 
826 static const struct file_operations filter_fops = {
827         .read  = filter_read,
828         .write = filter_write,
829         .llseek = default_llseek,
830 };
831 
832 static int dump_show(struct seq_file *seq, void *v)
833 {
834         int idx;
835 
836         for (idx = 0; idx < HASH_SIZE; idx++) {
837                 struct hash_bucket *bucket = &dma_entry_hash[idx];
838                 struct dma_debug_entry *entry;
839                 unsigned long flags;
840 
841                 spin_lock_irqsave(&bucket->lock, flags);
842                 list_for_each_entry(entry, &bucket->list, list) {
843                         seq_printf(seq,
844                                    "%s %s %s idx %d P=%llx N=%lx D=%llx L=%llx %s %s\n",
845                                    dev_name(entry->dev),
846                                    dev_driver_string(entry->dev),
847                                    type2name[entry->type], idx,
848                                    phys_addr(entry), entry->pfn,
849                                    entry->dev_addr, entry->size,
850                                    dir2name[entry->direction],
851                                    maperr2str[entry->map_err_type]);
852                 }
853                 spin_unlock_irqrestore(&bucket->lock, flags);
854         }
855         return 0;
856 }
857 DEFINE_SHOW_ATTRIBUTE(dump);
858 
859 static void dma_debug_fs_init(void)
860 {
861         struct dentry *dentry = debugfs_create_dir("dma-api", NULL);
862 
863         debugfs_create_bool("disabled", 0444, dentry, &global_disable);
864         debugfs_create_u32("error_count", 0444, dentry, &error_count);
865         debugfs_create_u32("all_errors", 0644, dentry, &show_all_errors);
866         debugfs_create_u32("num_errors", 0644, dentry, &show_num_errors);
867         debugfs_create_u32("num_free_entries", 0444, dentry, &num_free_entries);
868         debugfs_create_u32("min_free_entries", 0444, dentry, &min_free_entries);
869         debugfs_create_u32("nr_total_entries", 0444, dentry, &nr_total_entries);
870         debugfs_create_file("driver_filter", 0644, dentry, NULL, &filter_fops);
871         debugfs_create_file("dump", 0444, dentry, NULL, &dump_fops);
872 }
873 
874 static int device_dma_allocations(struct device *dev, struct dma_debug_entry **out_entry)
875 {
876         struct dma_debug_entry *entry;
877         unsigned long flags;
878         int count = 0, i;
879 
880         for (i = 0; i < HASH_SIZE; ++i) {
881                 spin_lock_irqsave(&dma_entry_hash[i].lock, flags);
882                 list_for_each_entry(entry, &dma_entry_hash[i].list, list) {
883                         if (entry->dev == dev) {
884                                 count += 1;
885                                 *out_entry = entry;
886                         }
887                 }
888                 spin_unlock_irqrestore(&dma_entry_hash[i].lock, flags);
889         }
890 
891         return count;
892 }
893 
894 static int dma_debug_device_change(struct notifier_block *nb, unsigned long action, void *data)
895 {
896         struct device *dev = data;
897         struct dma_debug_entry *uninitialized_var(entry);
898         int count;
899 
900         if (dma_debug_disabled())
901                 return 0;
902 
903         switch (action) {
904         case BUS_NOTIFY_UNBOUND_DRIVER:
905                 count = device_dma_allocations(dev, &entry);
906                 if (count == 0)
907                         break;
908                 err_printk(dev, entry, "device driver has pending "
909                                 "DMA allocations while released from device "
910                                 "[count=%d]\n"
911                                 "One of leaked entries details: "
912                                 "[device address=0x%016llx] [size=%llu bytes] "
913                                 "[mapped with %s] [mapped as %s]\n",
914                         count, entry->dev_addr, entry->size,
915                         dir2name[entry->direction], type2name[entry->type]);
916                 break;
917         default:
918                 break;
919         }
920 
921         return 0;
922 }
923 
924 void dma_debug_add_bus(struct bus_type *bus)
925 {
926         struct notifier_block *nb;
927 
928         if (dma_debug_disabled())
929                 return;
930 
931         nb = kzalloc(sizeof(struct notifier_block), GFP_KERNEL);
932         if (nb == NULL) {
933                 pr_err("dma_debug_add_bus: out of memory\n");
934                 return;
935         }
936 
937         nb->notifier_call = dma_debug_device_change;
938 
939         bus_register_notifier(bus, nb);
940 }
941 
942 static int dma_debug_init(void)
943 {
944         int i, nr_pages;
945 
946         /* Do not use dma_debug_initialized here, since we really want to be
947          * called to set dma_debug_initialized
948          */
949         if (global_disable)
950                 return 0;
951 
952         for (i = 0; i < HASH_SIZE; ++i) {
953                 INIT_LIST_HEAD(&dma_entry_hash[i].list);
954                 spin_lock_init(&dma_entry_hash[i].lock);
955         }
956 
957         dma_debug_fs_init();
958 
959         nr_pages = DIV_ROUND_UP(nr_prealloc_entries, DMA_DEBUG_DYNAMIC_ENTRIES);
960         for (i = 0; i < nr_pages; ++i)
961                 dma_debug_create_entries(GFP_KERNEL);
962         if (num_free_entries >= nr_prealloc_entries) {
963                 pr_info("preallocated %d debug entries\n", nr_total_entries);
964         } else if (num_free_entries > 0) {
965                 pr_warn("%d debug entries requested but only %d allocated\n",
966                         nr_prealloc_entries, nr_total_entries);
967         } else {
968                 pr_err("debugging out of memory error - disabled\n");
969                 global_disable = true;
970 
971                 return 0;
972         }
973         min_free_entries = num_free_entries;
974 
975         dma_debug_initialized = true;
976 
977         pr_info("debugging enabled by kernel config\n");
978         return 0;
979 }
980 core_initcall(dma_debug_init);
981 
982 static __init int dma_debug_cmdline(char *str)
983 {
984         if (!str)
985                 return -EINVAL;
986 
987         if (strncmp(str, "off", 3) == 0) {
988                 pr_info("debugging disabled on kernel command line\n");
989                 global_disable = true;
990         }
991 
992         return 0;
993 }
994 
995 static __init int dma_debug_entries_cmdline(char *str)
996 {
997         if (!str)
998                 return -EINVAL;
999         if (!get_option(&str, &nr_prealloc_entries))
1000                 nr_prealloc_entries = PREALLOC_DMA_DEBUG_ENTRIES;
1001         return 0;
1002 }
1003 
1004 __setup("dma_debug=", dma_debug_cmdline);
1005 __setup("dma_debug_entries=", dma_debug_entries_cmdline);
1006 
1007 static void check_unmap(struct dma_debug_entry *ref)
1008 {
1009         struct dma_debug_entry *entry;
1010         struct hash_bucket *bucket;
1011         unsigned long flags;
1012 
1013         bucket = get_hash_bucket(ref, &flags);
1014         entry = bucket_find_exact(bucket, ref);
1015 
1016         if (!entry) {
1017                 /* must drop lock before calling dma_mapping_error */
1018                 put_hash_bucket(bucket, &flags);
1019 
1020                 if (dma_mapping_error(ref->dev, ref->dev_addr)) {
1021                         err_printk(ref->dev, NULL,
1022                                    "device driver tries to free an "
1023                                    "invalid DMA memory address\n");
1024                 } else {
1025                         err_printk(ref->dev, NULL,
1026                                    "device driver tries to free DMA "
1027                                    "memory it has not allocated [device "
1028                                    "address=0x%016llx] [size=%llu bytes]\n",
1029                                    ref->dev_addr, ref->size);
1030                 }
1031                 return;
1032         }
1033 
1034         if (ref->size != entry->size) {
1035                 err_printk(ref->dev, entry, "device driver frees "
1036                            "DMA memory with different size "
1037                            "[device address=0x%016llx] [map size=%llu bytes] "
1038                            "[unmap size=%llu bytes]\n",
1039                            ref->dev_addr, entry->size, ref->size);
1040         }
1041 
1042         if (ref->type != entry->type) {
1043                 err_printk(ref->dev, entry, "device driver frees "
1044                            "DMA memory with wrong function "
1045                            "[device address=0x%016llx] [size=%llu bytes] "
1046                            "[mapped as %s] [unmapped as %s]\n",
1047                            ref->dev_addr, ref->size,
1048                            type2name[entry->type], type2name[ref->type]);
1049         } else if ((entry->type == dma_debug_coherent) &&
1050                    (phys_addr(ref) != phys_addr(entry))) {
1051                 err_printk(ref->dev, entry, "device driver frees "
1052                            "DMA memory with different CPU address "
1053                            "[device address=0x%016llx] [size=%llu bytes] "
1054                            "[cpu alloc address=0x%016llx] "
1055                            "[cpu free address=0x%016llx]",
1056                            ref->dev_addr, ref->size,
1057                            phys_addr(entry),
1058                            phys_addr(ref));
1059         }
1060 
1061         if (ref->sg_call_ents && ref->type == dma_debug_sg &&
1062             ref->sg_call_ents != entry->sg_call_ents) {
1063                 err_printk(ref->dev, entry, "device driver frees "
1064                            "DMA sg list with different entry count "
1065                            "[map count=%d] [unmap count=%d]\n",
1066                            entry->sg_call_ents, ref->sg_call_ents);
1067         }
1068 
1069         /*
1070          * This may be no bug in reality - but most implementations of the
1071          * DMA API don't handle this properly, so check for it here
1072          */
1073         if (ref->direction != entry->direction) {
1074                 err_printk(ref->dev, entry, "device driver frees "
1075                            "DMA memory with different direction "
1076                            "[device address=0x%016llx] [size=%llu bytes] "
1077                            "[mapped with %s] [unmapped with %s]\n",
1078                            ref->dev_addr, ref->size,
1079                            dir2name[entry->direction],
1080                            dir2name[ref->direction]);
1081         }
1082 
1083         /*
1084          * Drivers should use dma_mapping_error() to check the returned
1085          * addresses of dma_map_single() and dma_map_page().
1086          * If not, print this warning message. See Documentation/DMA-API.txt.
1087          */
1088         if (entry->map_err_type == MAP_ERR_NOT_CHECKED) {
1089                 err_printk(ref->dev, entry,
1090                            "device driver failed to check map error"
1091                            "[device address=0x%016llx] [size=%llu bytes] "
1092                            "[mapped as %s]",
1093                            ref->dev_addr, ref->size,
1094                            type2name[entry->type]);
1095         }
1096 
1097         hash_bucket_del(entry);
1098         dma_entry_free(entry);
1099 
1100         put_hash_bucket(bucket, &flags);
1101 }
1102 
1103 static void check_for_stack(struct device *dev,
1104                             struct page *page, size_t offset)
1105 {
1106         void *addr;
1107         struct vm_struct *stack_vm_area = task_stack_vm_area(current);
1108 
1109         if (!stack_vm_area) {
1110                 /* Stack is direct-mapped. */
1111                 if (PageHighMem(page))
1112                         return;
1113                 addr = page_address(page) + offset;
1114                 if (object_is_on_stack(addr))
1115                         err_printk(dev, NULL, "device driver maps memory from stack [addr=%p]\n", addr);
1116         } else {
1117                 /* Stack is vmalloced. */
1118                 int i;
1119 
1120                 for (i = 0; i < stack_vm_area->nr_pages; i++) {
1121                         if (page != stack_vm_area->pages[i])
1122                                 continue;
1123 
1124                         addr = (u8 *)current->stack + i * PAGE_SIZE + offset;
1125                         err_printk(dev, NULL, "device driver maps memory from stack [probable addr=%p]\n", addr);
1126                         break;
1127                 }
1128         }
1129 }
1130 
1131 static inline bool overlap(void *addr, unsigned long len, void *start, void *end)
1132 {
1133         unsigned long a1 = (unsigned long)addr;
1134         unsigned long b1 = a1 + len;
1135         unsigned long a2 = (unsigned long)start;
1136         unsigned long b2 = (unsigned long)end;
1137 
1138         return !(b1 <= a2 || a1 >= b2);
1139 }
1140 
1141 static void check_for_illegal_area(struct device *dev, void *addr, unsigned long len)
1142 {
1143         if (overlap(addr, len, _stext, _etext) ||
1144             overlap(addr, len, __start_rodata, __end_rodata))
1145                 err_printk(dev, NULL, "device driver maps memory from kernel text or rodata [addr=%p] [len=%lu]\n", addr, len);
1146 }
1147 
1148 static void check_sync(struct device *dev,
1149                        struct dma_debug_entry *ref,
1150                        bool to_cpu)
1151 {
1152         struct dma_debug_entry *entry;
1153         struct hash_bucket *bucket;
1154         unsigned long flags;
1155 
1156         bucket = get_hash_bucket(ref, &flags);
1157 
1158         entry = bucket_find_contain(&bucket, ref, &flags);
1159 
1160         if (!entry) {
1161                 err_printk(dev, NULL, "device driver tries "
1162                                 "to sync DMA memory it has not allocated "
1163                                 "[device address=0x%016llx] [size=%llu bytes]\n",
1164                                 (unsigned long long)ref->dev_addr, ref->size);
1165                 goto out;
1166         }
1167 
1168         if (ref->size > entry->size) {
1169                 err_printk(dev, entry, "device driver syncs"
1170                                 " DMA memory outside allocated range "
1171                                 "[device address=0x%016llx] "
1172                                 "[allocation size=%llu bytes] "
1173                                 "[sync offset+size=%llu]\n",
1174                                 entry->dev_addr, entry->size,
1175                                 ref->size);
1176         }
1177 
1178         if (entry->direction == DMA_BIDIRECTIONAL)
1179                 goto out;
1180 
1181         if (ref->direction != entry->direction) {
1182                 err_printk(dev, entry, "device driver syncs "
1183                                 "DMA memory with different direction "
1184                                 "[device address=0x%016llx] [size=%llu bytes] "
1185                                 "[mapped with %s] [synced with %s]\n",
1186                                 (unsigned long long)ref->dev_addr, entry->size,
1187                                 dir2name[entry->direction],
1188                                 dir2name[ref->direction]);
1189         }
1190 
1191         if (to_cpu && !(entry->direction == DMA_FROM_DEVICE) &&
1192                       !(ref->direction == DMA_TO_DEVICE))
1193                 err_printk(dev, entry, "device driver syncs "
1194                                 "device read-only DMA memory for cpu "
1195                                 "[device address=0x%016llx] [size=%llu bytes] "
1196                                 "[mapped with %s] [synced with %s]\n",
1197                                 (unsigned long long)ref->dev_addr, entry->size,
1198                                 dir2name[entry->direction],
1199                                 dir2name[ref->direction]);
1200 
1201         if (!to_cpu && !(entry->direction == DMA_TO_DEVICE) &&
1202                        !(ref->direction == DMA_FROM_DEVICE))
1203                 err_printk(dev, entry, "device driver syncs "
1204                                 "device write-only DMA memory to device "
1205                                 "[device address=0x%016llx] [size=%llu bytes] "
1206                                 "[mapped with %s] [synced with %s]\n",
1207                                 (unsigned long long)ref->dev_addr, entry->size,
1208                                 dir2name[entry->direction],
1209                                 dir2name[ref->direction]);
1210 
1211         if (ref->sg_call_ents && ref->type == dma_debug_sg &&
1212             ref->sg_call_ents != entry->sg_call_ents) {
1213                 err_printk(ref->dev, entry, "device driver syncs "
1214                            "DMA sg list with different entry count "
1215                            "[map count=%d] [sync count=%d]\n",
1216                            entry->sg_call_ents, ref->sg_call_ents);
1217         }
1218 
1219 out:
1220         put_hash_bucket(bucket, &flags);
1221 }
1222 
1223 static void check_sg_segment(struct device *dev, struct scatterlist *sg)
1224 {
1225 #ifdef CONFIG_DMA_API_DEBUG_SG
1226         unsigned int max_seg = dma_get_max_seg_size(dev);
1227         u64 start, end, boundary = dma_get_seg_boundary(dev);
1228 
1229         /*
1230          * Either the driver forgot to set dma_parms appropriately, or
1231          * whoever generated the list forgot to check them.
1232          */
1233         if (sg->length > max_seg)
1234                 err_printk(dev, NULL, "mapping sg segment longer than device claims to support [len=%u] [max=%u]\n",
1235                            sg->length, max_seg);
1236         /*
1237          * In some cases this could potentially be the DMA API
1238          * implementation's fault, but it would usually imply that
1239          * the scatterlist was built inappropriately to begin with.
1240          */
1241         start = sg_dma_address(sg);
1242         end = start + sg_dma_len(sg) - 1;
1243         if ((start ^ end) & ~boundary)
1244                 err_printk(dev, NULL, "mapping sg segment across boundary [start=0x%016llx] [end=0x%016llx] [boundary=0x%016llx]\n",
1245                            start, end, boundary);
1246 #endif
1247 }
1248 
1249 void debug_dma_map_single(struct device *dev, const void *addr,
1250                             unsigned long len)
1251 {
1252         if (unlikely(dma_debug_disabled()))
1253                 return;
1254 
1255         if (!virt_addr_valid(addr))
1256                 err_printk(dev, NULL, "device driver maps memory from invalid area [addr=%p] [len=%lu]\n",
1257                            addr, len);
1258 
1259         if (is_vmalloc_addr(addr))
1260                 err_printk(dev, NULL, "device driver maps memory from vmalloc area [addr=%p] [len=%lu]\n",
1261                            addr, len);
1262 }
1263 EXPORT_SYMBOL(debug_dma_map_single);
1264 
1265 void debug_dma_map_page(struct device *dev, struct page *page, size_t offset,
1266                         size_t size, int direction, dma_addr_t dma_addr)
1267 {
1268         struct dma_debug_entry *entry;
1269 
1270         if (unlikely(dma_debug_disabled()))
1271                 return;
1272 
1273         if (dma_mapping_error(dev, dma_addr))
1274                 return;
1275 
1276         entry = dma_entry_alloc();
1277         if (!entry)
1278                 return;
1279 
1280         entry->dev       = dev;
1281         entry->type      = dma_debug_single;
1282         entry->pfn       = page_to_pfn(page);
1283         entry->offset    = offset,
1284         entry->dev_addr  = dma_addr;
1285         entry->size      = size;
1286         entry->direction = direction;
1287         entry->map_err_type = MAP_ERR_NOT_CHECKED;
1288 
1289         check_for_stack(dev, page, offset);
1290 
1291         if (!PageHighMem(page)) {
1292                 void *addr = page_address(page) + offset;
1293 
1294                 check_for_illegal_area(dev, addr, size);
1295         }
1296 
1297         add_dma_entry(entry);
1298 }
1299 EXPORT_SYMBOL(debug_dma_map_page);
1300 
1301 void debug_dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
1302 {
1303         struct dma_debug_entry ref;
1304         struct dma_debug_entry *entry;
1305         struct hash_bucket *bucket;
1306         unsigned long flags;
1307 
1308         if (unlikely(dma_debug_disabled()))
1309                 return;
1310 
1311         ref.dev = dev;
1312         ref.dev_addr = dma_addr;
1313         bucket = get_hash_bucket(&ref, &flags);
1314 
1315         list_for_each_entry(entry, &bucket->list, list) {
1316                 if (!exact_match(&ref, entry))
1317                         continue;
1318 
1319                 /*
1320                  * The same physical address can be mapped multiple
1321                  * times. Without a hardware IOMMU this results in the
1322                  * same device addresses being put into the dma-debug
1323                  * hash multiple times too. This can result in false
1324                  * positives being reported. Therefore we implement a
1325                  * best-fit algorithm here which updates the first entry
1326                  * from the hash which fits the reference value and is
1327                  * not currently listed as being checked.
1328                  */
1329                 if (entry->map_err_type == MAP_ERR_NOT_CHECKED) {
1330                         entry->map_err_type = MAP_ERR_CHECKED;
1331                         break;
1332                 }
1333         }
1334 
1335         put_hash_bucket(bucket, &flags);
1336 }
1337 EXPORT_SYMBOL(debug_dma_mapping_error);
1338 
1339 void debug_dma_unmap_page(struct device *dev, dma_addr_t addr,
1340                           size_t size, int direction)
1341 {
1342         struct dma_debug_entry ref = {
1343                 .type           = dma_debug_single,
1344                 .dev            = dev,
1345                 .dev_addr       = addr,
1346                 .size           = size,
1347                 .direction      = direction,
1348         };
1349 
1350         if (unlikely(dma_debug_disabled()))
1351                 return;
1352         check_unmap(&ref);
1353 }
1354 EXPORT_SYMBOL(debug_dma_unmap_page);
1355 
1356 void debug_dma_map_sg(struct device *dev, struct scatterlist *sg,
1357                       int nents, int mapped_ents, int direction)
1358 {
1359         struct dma_debug_entry *entry;
1360         struct scatterlist *s;
1361         int i;
1362 
1363         if (unlikely(dma_debug_disabled()))
1364                 return;
1365 
1366         for_each_sg(sg, s, mapped_ents, i) {
1367                 entry = dma_entry_alloc();
1368                 if (!entry)
1369                         return;
1370 
1371                 entry->type           = dma_debug_sg;
1372                 entry->dev            = dev;
1373                 entry->pfn            = page_to_pfn(sg_page(s));
1374                 entry->offset         = s->offset,
1375                 entry->size           = sg_dma_len(s);
1376                 entry->dev_addr       = sg_dma_address(s);
1377                 entry->direction      = direction;
1378                 entry->sg_call_ents   = nents;
1379                 entry->sg_mapped_ents = mapped_ents;
1380 
1381                 check_for_stack(dev, sg_page(s), s->offset);
1382 
1383                 if (!PageHighMem(sg_page(s))) {
1384                         check_for_illegal_area(dev, sg_virt(s), sg_dma_len(s));
1385                 }
1386 
1387                 check_sg_segment(dev, s);
1388 
1389                 add_dma_entry(entry);
1390         }
1391 }
1392 EXPORT_SYMBOL(debug_dma_map_sg);
1393 
1394 static int get_nr_mapped_entries(struct device *dev,
1395                                  struct dma_debug_entry *ref)
1396 {
1397         struct dma_debug_entry *entry;
1398         struct hash_bucket *bucket;
1399         unsigned long flags;
1400         int mapped_ents;
1401 
1402         bucket       = get_hash_bucket(ref, &flags);
1403         entry        = bucket_find_exact(bucket, ref);
1404         mapped_ents  = 0;
1405 
1406         if (entry)
1407                 mapped_ents = entry->sg_mapped_ents;
1408         put_hash_bucket(bucket, &flags);
1409 
1410         return mapped_ents;
1411 }
1412 
1413 void debug_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
1414                         int nelems, int dir)
1415 {
1416         struct scatterlist *s;
1417         int mapped_ents = 0, i;
1418 
1419         if (unlikely(dma_debug_disabled()))
1420                 return;
1421 
1422         for_each_sg(sglist, s, nelems, i) {
1423 
1424                 struct dma_debug_entry ref = {
1425                         .type           = dma_debug_sg,
1426                         .dev            = dev,
1427                         .pfn            = page_to_pfn(sg_page(s)),
1428                         .offset         = s->offset,
1429                         .dev_addr       = sg_dma_address(s),
1430                         .size           = sg_dma_len(s),
1431                         .direction      = dir,
1432                         .sg_call_ents   = nelems,
1433                 };
1434 
1435                 if (mapped_ents && i >= mapped_ents)
1436                         break;
1437 
1438                 if (!i)
1439                         mapped_ents = get_nr_mapped_entries(dev, &ref);
1440 
1441                 check_unmap(&ref);
1442         }
1443 }
1444 EXPORT_SYMBOL(debug_dma_unmap_sg);
1445 
1446 void debug_dma_alloc_coherent(struct device *dev, size_t size,
1447                               dma_addr_t dma_addr, void *virt)
1448 {
1449         struct dma_debug_entry *entry;
1450 
1451         if (unlikely(dma_debug_disabled()))
1452                 return;
1453 
1454         if (unlikely(virt == NULL))
1455                 return;
1456 
1457         /* handle vmalloc and linear addresses */
1458         if (!is_vmalloc_addr(virt) && !virt_addr_valid(virt))
1459                 return;
1460 
1461         entry = dma_entry_alloc();
1462         if (!entry)
1463                 return;
1464 
1465         entry->type      = dma_debug_coherent;
1466         entry->dev       = dev;
1467         entry->offset    = offset_in_page(virt);
1468         entry->size      = size;
1469         entry->dev_addr  = dma_addr;
1470         entry->direction = DMA_BIDIRECTIONAL;
1471 
1472         if (is_vmalloc_addr(virt))
1473                 entry->pfn = vmalloc_to_pfn(virt);
1474         else
1475                 entry->pfn = page_to_pfn(virt_to_page(virt));
1476 
1477         add_dma_entry(entry);
1478 }
1479 
1480 void debug_dma_free_coherent(struct device *dev, size_t size,
1481                          void *virt, dma_addr_t addr)
1482 {
1483         struct dma_debug_entry ref = {
1484                 .type           = dma_debug_coherent,
1485                 .dev            = dev,
1486                 .offset         = offset_in_page(virt),
1487                 .dev_addr       = addr,
1488                 .size           = size,
1489                 .direction      = DMA_BIDIRECTIONAL,
1490         };
1491 
1492         /* handle vmalloc and linear addresses */
1493         if (!is_vmalloc_addr(virt) && !virt_addr_valid(virt))
1494                 return;
1495 
1496         if (is_vmalloc_addr(virt))
1497                 ref.pfn = vmalloc_to_pfn(virt);
1498         else
1499                 ref.pfn = page_to_pfn(virt_to_page(virt));
1500 
1501         if (unlikely(dma_debug_disabled()))
1502                 return;
1503 
1504         check_unmap(&ref);
1505 }
1506 
1507 void debug_dma_map_resource(struct device *dev, phys_addr_t addr, size_t size,
1508                             int direction, dma_addr_t dma_addr)
1509 {
1510         struct dma_debug_entry *entry;
1511 
1512         if (unlikely(dma_debug_disabled()))
1513                 return;
1514 
1515         entry = dma_entry_alloc();
1516         if (!entry)
1517                 return;
1518 
1519         entry->type             = dma_debug_resource;
1520         entry->dev              = dev;
1521         entry->pfn              = PHYS_PFN(addr);
1522         entry->offset           = offset_in_page(addr);
1523         entry->size             = size;
1524         entry->dev_addr         = dma_addr;
1525         entry->direction        = direction;
1526         entry->map_err_type     = MAP_ERR_NOT_CHECKED;
1527 
1528         add_dma_entry(entry);
1529 }
1530 EXPORT_SYMBOL(debug_dma_map_resource);
1531 
1532 void debug_dma_unmap_resource(struct device *dev, dma_addr_t dma_addr,
1533                               size_t size, int direction)
1534 {
1535         struct dma_debug_entry ref = {
1536                 .type           = dma_debug_resource,
1537                 .dev            = dev,
1538                 .dev_addr       = dma_addr,
1539                 .size           = size,
1540                 .direction      = direction,
1541         };
1542 
1543         if (unlikely(dma_debug_disabled()))
1544                 return;
1545 
1546         check_unmap(&ref);
1547 }
1548 EXPORT_SYMBOL(debug_dma_unmap_resource);
1549 
1550 void debug_dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_handle,
1551                                    size_t size, int direction)
1552 {
1553         struct dma_debug_entry ref;
1554 
1555         if (unlikely(dma_debug_disabled()))
1556                 return;
1557 
1558         ref.type         = dma_debug_single;
1559         ref.dev          = dev;
1560         ref.dev_addr     = dma_handle;
1561         ref.size         = size;
1562         ref.direction    = direction;
1563         ref.sg_call_ents = 0;
1564 
1565         check_sync(dev, &ref, true);
1566 }
1567 EXPORT_SYMBOL(debug_dma_sync_single_for_cpu);
1568 
1569 void debug_dma_sync_single_for_device(struct device *dev,
1570                                       dma_addr_t dma_handle, size_t size,
1571                                       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, false);
1586 }
1587 EXPORT_SYMBOL(debug_dma_sync_single_for_device);
1588 
1589 void debug_dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
1590                                int nelems, int direction)
1591 {
1592         struct scatterlist *s;
1593         int mapped_ents = 0, i;
1594 
1595         if (unlikely(dma_debug_disabled()))
1596                 return;
1597 
1598         for_each_sg(sg, s, nelems, i) {
1599 
1600                 struct dma_debug_entry ref = {
1601                         .type           = dma_debug_sg,
1602                         .dev            = dev,
1603                         .pfn            = page_to_pfn(sg_page(s)),
1604                         .offset         = s->offset,
1605                         .dev_addr       = sg_dma_address(s),
1606                         .size           = sg_dma_len(s),
1607                         .direction      = direction,
1608                         .sg_call_ents   = nelems,
1609                 };
1610 
1611                 if (!i)
1612                         mapped_ents = get_nr_mapped_entries(dev, &ref);
1613 
1614                 if (i >= mapped_ents)
1615                         break;
1616 
1617                 check_sync(dev, &ref, true);
1618         }
1619 }
1620 EXPORT_SYMBOL(debug_dma_sync_sg_for_cpu);
1621 
1622 void debug_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
1623                                   int nelems, int direction)
1624 {
1625         struct scatterlist *s;
1626         int mapped_ents = 0, i;
1627 
1628         if (unlikely(dma_debug_disabled()))
1629                 return;
1630 
1631         for_each_sg(sg, s, nelems, i) {
1632 
1633                 struct dma_debug_entry ref = {
1634                         .type           = dma_debug_sg,
1635                         .dev            = dev,
1636                         .pfn            = page_to_pfn(sg_page(s)),
1637                         .offset         = s->offset,
1638                         .dev_addr       = sg_dma_address(s),
1639                         .size           = sg_dma_len(s),
1640                         .direction      = direction,
1641                         .sg_call_ents   = nelems,
1642                 };
1643                 if (!i)
1644                         mapped_ents = get_nr_mapped_entries(dev, &ref);
1645 
1646                 if (i >= mapped_ents)
1647                         break;
1648 
1649                 check_sync(dev, &ref, false);
1650         }
1651 }
1652 EXPORT_SYMBOL(debug_dma_sync_sg_for_device);
1653 
1654 static int __init dma_debug_driver_setup(char *str)
1655 {
1656         int i;
1657 
1658         for (i = 0; i < NAME_MAX_LEN - 1; ++i, ++str) {
1659                 current_driver_name[i] = *str;
1660                 if (*str == 0)
1661                         break;
1662         }
1663 
1664         if (current_driver_name[0])
1665                 pr_info("enable driver filter for driver [%s]\n",
1666                         current_driver_name);
1667 
1668 
1669         return 1;
1670 }
1671 __setup("dma_debug_driver=", dma_debug_driver_setup);
1672 

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