xref: /linux/kernel/dma/debug.c (revision 133577cad6bf48e5a7848c4338124081393bfe8a)
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Copyright (C) 2008 Advanced Micro Devices, Inc.
4  *
5  * Author: Joerg Roedel <joerg.roedel@amd.com>
6  */
7 
8 #define pr_fmt(fmt)	"DMA-API: " fmt
9 
10 #include <linux/sched/task_stack.h>
11 #include <linux/scatterlist.h>
12 #include <linux/dma-map-ops.h>
13 #include <linux/sched/task.h>
14 #include <linux/stacktrace.h>
15 #include <linux/spinlock.h>
16 #include <linux/vmalloc.h>
17 #include <linux/debugfs.h>
18 #include <linux/uaccess.h>
19 #include <linux/export.h>
20 #include <linux/device.h>
21 #include <linux/types.h>
22 #include <linux/sched.h>
23 #include <linux/ctype.h>
24 #include <linux/list.h>
25 #include <linux/slab.h>
26 #include <asm/sections.h>
27 #include "debug.h"
28 
29 #define HASH_SIZE       16384ULL
30 #define HASH_FN_SHIFT   13
31 #define HASH_FN_MASK    (HASH_SIZE - 1)
32 
33 #define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16)
34 /* If the pool runs out, add this many new entries at once */
35 #define DMA_DEBUG_DYNAMIC_ENTRIES (PAGE_SIZE / sizeof(struct dma_debug_entry))
36 
37 enum {
38 	dma_debug_single,
39 	dma_debug_sg,
40 	dma_debug_coherent,
41 	dma_debug_resource,
42 };
43 
44 enum map_err_types {
45 	MAP_ERR_CHECK_NOT_APPLICABLE,
46 	MAP_ERR_NOT_CHECKED,
47 	MAP_ERR_CHECKED,
48 };
49 
50 #define DMA_DEBUG_STACKTRACE_ENTRIES 5
51 
52 /**
53  * struct dma_debug_entry - track a dma_map* or dma_alloc_coherent mapping
54  * @list: node on pre-allocated free_entries list
55  * @dev: 'dev' argument to dma_map_{page|single|sg} or dma_alloc_coherent
56  * @dev_addr: dma address
57  * @size: length of the mapping
58  * @type: single, page, sg, coherent
59  * @direction: enum dma_data_direction
60  * @sg_call_ents: 'nents' from dma_map_sg
61  * @sg_mapped_ents: 'mapped_ents' from dma_map_sg
62  * @paddr: physical start address of the mapping
63  * @map_err_type: track whether dma_mapping_error() was checked
64  * @stack_len: number of backtrace entries in @stack_entries
65  * @stack_entries: stack of backtrace history
66  */
67 struct dma_debug_entry {
68 	struct list_head list;
69 	struct device    *dev;
70 	u64              dev_addr;
71 	u64              size;
72 	int              type;
73 	int              direction;
74 	int		 sg_call_ents;
75 	int		 sg_mapped_ents;
76 	phys_addr_t	 paddr;
77 	enum map_err_types  map_err_type;
78 #ifdef CONFIG_STACKTRACE
79 	unsigned int	stack_len;
80 	unsigned long	stack_entries[DMA_DEBUG_STACKTRACE_ENTRIES];
81 #endif
82 } ____cacheline_aligned_in_smp;
83 
84 typedef bool (*match_fn)(struct dma_debug_entry *, struct dma_debug_entry *);
85 
86 struct hash_bucket {
87 	struct list_head list;
88 	spinlock_t lock;
89 };
90 
91 /* Hash list to save the allocated dma addresses */
92 static struct hash_bucket dma_entry_hash[HASH_SIZE];
93 /* List of pre-allocated dma_debug_entry's */
94 static LIST_HEAD(free_entries);
95 /* Lock for the list above */
96 static DEFINE_SPINLOCK(free_entries_lock);
97 
98 /* Global disable flag - will be set in case of an error */
99 static bool global_disable __read_mostly;
100 
101 /* Early initialization disable flag, set at the end of dma_debug_init */
102 static bool dma_debug_initialized __read_mostly;
103 
dma_debug_disabled(void)104 static inline bool dma_debug_disabled(void)
105 {
106 	return global_disable || !dma_debug_initialized;
107 }
108 
109 /* Global error count */
110 static u32 error_count;
111 
112 /* Global error show enable*/
113 static u32 show_all_errors __read_mostly;
114 /* Number of errors to show */
115 static u32 show_num_errors = 1;
116 
117 static u32 num_free_entries;
118 static u32 min_free_entries;
119 static u32 nr_total_entries;
120 
121 /* number of preallocated entries requested by kernel cmdline */
122 static u32 nr_prealloc_entries = PREALLOC_DMA_DEBUG_ENTRIES;
123 
124 /* per-driver filter related state */
125 
126 #define NAME_MAX_LEN	64
127 
128 static char                  current_driver_name[NAME_MAX_LEN] __read_mostly;
129 static struct device_driver *current_driver                    __read_mostly;
130 
131 static DEFINE_RWLOCK(driver_name_lock);
132 
133 static const char *const maperr2str[] = {
134 	[MAP_ERR_CHECK_NOT_APPLICABLE] = "dma map error check not applicable",
135 	[MAP_ERR_NOT_CHECKED] = "dma map error not checked",
136 	[MAP_ERR_CHECKED] = "dma map error checked",
137 };
138 
139 static const char *type2name[] = {
140 	[dma_debug_single] = "single",
141 	[dma_debug_sg] = "scatter-gather",
142 	[dma_debug_coherent] = "coherent",
143 	[dma_debug_resource] = "resource",
144 };
145 
146 static const char *dir2name[] = {
147 	[DMA_BIDIRECTIONAL]	= "DMA_BIDIRECTIONAL",
148 	[DMA_TO_DEVICE]		= "DMA_TO_DEVICE",
149 	[DMA_FROM_DEVICE]	= "DMA_FROM_DEVICE",
150 	[DMA_NONE]		= "DMA_NONE",
151 };
152 
153 /*
154  * The access to some variables in this macro is racy. We can't use atomic_t
155  * here because all these variables are exported to debugfs. Some of them even
156  * writeable. This is also the reason why a lock won't help much. But anyway,
157  * the races are no big deal. Here is why:
158  *
159  *   error_count: the addition is racy, but the worst thing that can happen is
160  *                that we don't count some errors
161  *   show_num_errors: the subtraction is racy. Also no big deal because in
162  *                    worst case this will result in one warning more in the
163  *                    system log than the user configured. This variable is
164  *                    writeable via debugfs.
165  */
dump_entry_trace(struct dma_debug_entry * entry)166 static inline void dump_entry_trace(struct dma_debug_entry *entry)
167 {
168 #ifdef CONFIG_STACKTRACE
169 	if (entry) {
170 		pr_warn("Mapped at:\n");
171 		stack_trace_print(entry->stack_entries, entry->stack_len, 0);
172 	}
173 #endif
174 }
175 
driver_filter(struct device * dev)176 static bool driver_filter(struct device *dev)
177 {
178 	struct device_driver *drv;
179 	unsigned long flags;
180 	bool ret;
181 
182 	/* driver filter off */
183 	if (likely(!current_driver_name[0]))
184 		return true;
185 
186 	/* driver filter on and initialized */
187 	if (current_driver && dev && dev->driver == current_driver)
188 		return true;
189 
190 	/* driver filter on, but we can't filter on a NULL device... */
191 	if (!dev)
192 		return false;
193 
194 	if (current_driver || !current_driver_name[0])
195 		return false;
196 
197 	/* driver filter on but not yet initialized */
198 	drv = dev->driver;
199 	if (!drv)
200 		return false;
201 
202 	/* lock to protect against change of current_driver_name */
203 	read_lock_irqsave(&driver_name_lock, flags);
204 
205 	ret = false;
206 	if (drv->name &&
207 	    strncmp(current_driver_name, drv->name, NAME_MAX_LEN - 1) == 0) {
208 		current_driver = drv;
209 		ret = true;
210 	}
211 
212 	read_unlock_irqrestore(&driver_name_lock, flags);
213 
214 	return ret;
215 }
216 
217 #define err_printk(dev, entry, format, arg...) do {			\
218 		error_count += 1;					\
219 		if (driver_filter(dev) &&				\
220 		    (show_all_errors || show_num_errors > 0)) {		\
221 			WARN(1, pr_fmt("%s %s: ") format,		\
222 			     dev ? dev_driver_string(dev) : "NULL",	\
223 			     dev ? dev_name(dev) : "NULL", ## arg);	\
224 			dump_entry_trace(entry);			\
225 		}							\
226 		if (!show_all_errors && show_num_errors > 0)		\
227 			show_num_errors -= 1;				\
228 	} while (0);
229 
230 /*
231  * Hash related functions
232  *
233  * Every DMA-API request is saved into a struct dma_debug_entry. To
234  * have quick access to these structs they are stored into a hash.
235  */
hash_fn(struct dma_debug_entry * entry)236 static int hash_fn(struct dma_debug_entry *entry)
237 {
238 	/*
239 	 * Hash function is based on the dma address.
240 	 * We use bits 20-27 here as the index into the hash
241 	 */
242 	return (entry->dev_addr >> HASH_FN_SHIFT) & HASH_FN_MASK;
243 }
244 
245 /*
246  * Request exclusive access to a hash bucket for a given dma_debug_entry.
247  */
get_hash_bucket(struct dma_debug_entry * entry,unsigned long * flags)248 static struct hash_bucket *get_hash_bucket(struct dma_debug_entry *entry,
249 					   unsigned long *flags)
250 	__acquires(&dma_entry_hash[idx].lock)
251 {
252 	int idx = hash_fn(entry);
253 	unsigned long __flags;
254 
255 	spin_lock_irqsave(&dma_entry_hash[idx].lock, __flags);
256 	*flags = __flags;
257 	return &dma_entry_hash[idx];
258 }
259 
260 /*
261  * Give up exclusive access to the hash bucket
262  */
put_hash_bucket(struct hash_bucket * bucket,unsigned long flags)263 static void put_hash_bucket(struct hash_bucket *bucket,
264 			    unsigned long flags)
265 	__releases(&bucket->lock)
266 {
267 	spin_unlock_irqrestore(&bucket->lock, flags);
268 }
269 
exact_match(struct dma_debug_entry * a,struct dma_debug_entry * b)270 static bool exact_match(struct dma_debug_entry *a, struct dma_debug_entry *b)
271 {
272 	return ((a->dev_addr == b->dev_addr) &&
273 		(a->dev == b->dev)) ? true : false;
274 }
275 
containing_match(struct dma_debug_entry * a,struct dma_debug_entry * b)276 static bool containing_match(struct dma_debug_entry *a,
277 			     struct dma_debug_entry *b)
278 {
279 	if (a->dev != b->dev)
280 		return false;
281 
282 	if ((b->dev_addr <= a->dev_addr) &&
283 	    ((b->dev_addr + b->size) >= (a->dev_addr + a->size)))
284 		return true;
285 
286 	return false;
287 }
288 
289 /*
290  * Search a given entry in the hash bucket list
291  */
__hash_bucket_find(struct hash_bucket * bucket,struct dma_debug_entry * ref,match_fn match)292 static struct dma_debug_entry *__hash_bucket_find(struct hash_bucket *bucket,
293 						  struct dma_debug_entry *ref,
294 						  match_fn match)
295 {
296 	struct dma_debug_entry *entry, *ret = NULL;
297 	int matches = 0, match_lvl, last_lvl = -1;
298 
299 	list_for_each_entry(entry, &bucket->list, list) {
300 		if (!match(ref, entry))
301 			continue;
302 
303 		/*
304 		 * Some drivers map the same physical address multiple
305 		 * times. Without a hardware IOMMU this results in the
306 		 * same device addresses being put into the dma-debug
307 		 * hash multiple times too. This can result in false
308 		 * positives being reported. Therefore we implement a
309 		 * best-fit algorithm here which returns the entry from
310 		 * the hash which fits best to the reference value
311 		 * instead of the first-fit.
312 		 */
313 		matches += 1;
314 		match_lvl = 0;
315 		entry->size         == ref->size         ? ++match_lvl : 0;
316 		entry->type         == ref->type         ? ++match_lvl : 0;
317 		entry->direction    == ref->direction    ? ++match_lvl : 0;
318 		entry->sg_call_ents == ref->sg_call_ents ? ++match_lvl : 0;
319 
320 		if (match_lvl == 4) {
321 			/* perfect-fit - return the result */
322 			return entry;
323 		} else if (match_lvl > last_lvl) {
324 			/*
325 			 * We found an entry that fits better then the
326 			 * previous one or it is the 1st match.
327 			 */
328 			last_lvl = match_lvl;
329 			ret      = entry;
330 		}
331 	}
332 
333 	/*
334 	 * If we have multiple matches but no perfect-fit, just return
335 	 * NULL.
336 	 */
337 	ret = (matches == 1) ? ret : NULL;
338 
339 	return ret;
340 }
341 
bucket_find_exact(struct hash_bucket * bucket,struct dma_debug_entry * ref)342 static struct dma_debug_entry *bucket_find_exact(struct hash_bucket *bucket,
343 						 struct dma_debug_entry *ref)
344 {
345 	return __hash_bucket_find(bucket, ref, exact_match);
346 }
347 
bucket_find_contain(struct hash_bucket ** bucket,struct dma_debug_entry * ref,unsigned long * flags)348 static struct dma_debug_entry *bucket_find_contain(struct hash_bucket **bucket,
349 						   struct dma_debug_entry *ref,
350 						   unsigned long *flags)
351 {
352 
353 	struct dma_debug_entry *entry, index = *ref;
354 	int limit = min(HASH_SIZE, (index.dev_addr >> HASH_FN_SHIFT) + 1);
355 
356 	for (int i = 0; i < limit; i++) {
357 		entry = __hash_bucket_find(*bucket, ref, containing_match);
358 
359 		if (entry)
360 			return entry;
361 
362 		/*
363 		 * Nothing found, go back a hash bucket
364 		 */
365 		put_hash_bucket(*bucket, *flags);
366 		index.dev_addr -= (1 << HASH_FN_SHIFT);
367 		*bucket = get_hash_bucket(&index, flags);
368 	}
369 
370 	return NULL;
371 }
372 
373 /*
374  * Add an entry to a hash bucket
375  */
hash_bucket_add(struct hash_bucket * bucket,struct dma_debug_entry * entry)376 static void hash_bucket_add(struct hash_bucket *bucket,
377 			    struct dma_debug_entry *entry)
378 {
379 	list_add_tail(&entry->list, &bucket->list);
380 }
381 
382 /*
383  * Remove entry from a hash bucket list
384  */
hash_bucket_del(struct dma_debug_entry * entry)385 static void hash_bucket_del(struct dma_debug_entry *entry)
386 {
387 	list_del(&entry->list);
388 }
389 
390 /*
391  * For each mapping (initial cacheline in the case of
392  * dma_alloc_coherent/dma_map_page, initial cacheline in each page of a
393  * scatterlist, or the cacheline specified in dma_map_single) insert
394  * into this tree using the cacheline as the key. At
395  * dma_unmap_{single|sg|page} or dma_free_coherent delete the entry.  If
396  * the entry already exists at insertion time add a tag as a reference
397  * count for the overlapping mappings.  For now, the overlap tracking
398  * just ensures that 'unmaps' balance 'maps' before marking the
399  * cacheline idle, but we should also be flagging overlaps as an API
400  * violation.
401  *
402  * Memory usage is mostly constrained by the maximum number of available
403  * dma-debug entries in that we need a free dma_debug_entry before
404  * inserting into the tree.  In the case of dma_map_page and
405  * dma_alloc_coherent there is only one dma_debug_entry and one
406  * dma_active_cacheline entry to track per event.  dma_map_sg(), on the
407  * other hand, consumes a single dma_debug_entry, but inserts 'nents'
408  * entries into the tree.
409  *
410  * Use __GFP_NOWARN because the printk from an OOM, to netconsole, could end
411  * up right back in the DMA debugging code, leading to a deadlock.
412  */
413 static RADIX_TREE(dma_active_cacheline, GFP_ATOMIC | __GFP_NOWARN);
414 static DEFINE_SPINLOCK(radix_lock);
415 #define ACTIVE_CACHELINE_MAX_OVERLAP ((1 << RADIX_TREE_MAX_TAGS) - 1)
416 #define CACHELINE_PER_PAGE_SHIFT (PAGE_SHIFT - L1_CACHE_SHIFT)
417 #define CACHELINES_PER_PAGE (1 << CACHELINE_PER_PAGE_SHIFT)
418 
to_cacheline_number(struct dma_debug_entry * entry)419 static phys_addr_t to_cacheline_number(struct dma_debug_entry *entry)
420 {
421 	return ((entry->paddr >> PAGE_SHIFT) << CACHELINE_PER_PAGE_SHIFT) +
422 		(offset_in_page(entry->paddr) >> L1_CACHE_SHIFT);
423 }
424 
active_cacheline_read_overlap(phys_addr_t cln)425 static int active_cacheline_read_overlap(phys_addr_t cln)
426 {
427 	int overlap = 0, i;
428 
429 	for (i = RADIX_TREE_MAX_TAGS - 1; i >= 0; i--)
430 		if (radix_tree_tag_get(&dma_active_cacheline, cln, i))
431 			overlap |= 1 << i;
432 	return overlap;
433 }
434 
active_cacheline_set_overlap(phys_addr_t cln,int overlap)435 static int active_cacheline_set_overlap(phys_addr_t cln, int overlap)
436 {
437 	int i;
438 
439 	if (overlap > ACTIVE_CACHELINE_MAX_OVERLAP || overlap < 0)
440 		return overlap;
441 
442 	for (i = RADIX_TREE_MAX_TAGS - 1; i >= 0; i--)
443 		if (overlap & 1 << i)
444 			radix_tree_tag_set(&dma_active_cacheline, cln, i);
445 		else
446 			radix_tree_tag_clear(&dma_active_cacheline, cln, i);
447 
448 	return overlap;
449 }
450 
active_cacheline_inc_overlap(phys_addr_t cln)451 static void active_cacheline_inc_overlap(phys_addr_t cln)
452 {
453 	int overlap = active_cacheline_read_overlap(cln);
454 
455 	overlap = active_cacheline_set_overlap(cln, ++overlap);
456 
457 	/* If we overflowed the overlap counter then we're potentially
458 	 * leaking dma-mappings.
459 	 */
460 	WARN_ONCE(overlap > ACTIVE_CACHELINE_MAX_OVERLAP,
461 		  pr_fmt("exceeded %d overlapping mappings of cacheline %pa\n"),
462 		  ACTIVE_CACHELINE_MAX_OVERLAP, &cln);
463 }
464 
active_cacheline_dec_overlap(phys_addr_t cln)465 static int active_cacheline_dec_overlap(phys_addr_t cln)
466 {
467 	int overlap = active_cacheline_read_overlap(cln);
468 
469 	return active_cacheline_set_overlap(cln, --overlap);
470 }
471 
active_cacheline_insert(struct dma_debug_entry * entry)472 static int active_cacheline_insert(struct dma_debug_entry *entry)
473 {
474 	phys_addr_t cln = to_cacheline_number(entry);
475 	unsigned long flags;
476 	int rc;
477 
478 	/* If the device is not writing memory then we don't have any
479 	 * concerns about the cpu consuming stale data.  This mitigates
480 	 * legitimate usages of overlapping mappings.
481 	 */
482 	if (entry->direction == DMA_TO_DEVICE)
483 		return 0;
484 
485 	spin_lock_irqsave(&radix_lock, flags);
486 	rc = radix_tree_insert(&dma_active_cacheline, cln, entry);
487 	if (rc == -EEXIST)
488 		active_cacheline_inc_overlap(cln);
489 	spin_unlock_irqrestore(&radix_lock, flags);
490 
491 	return rc;
492 }
493 
active_cacheline_remove(struct dma_debug_entry * entry)494 static void active_cacheline_remove(struct dma_debug_entry *entry)
495 {
496 	phys_addr_t cln = to_cacheline_number(entry);
497 	unsigned long flags;
498 
499 	/* ...mirror the insert case */
500 	if (entry->direction == DMA_TO_DEVICE)
501 		return;
502 
503 	spin_lock_irqsave(&radix_lock, flags);
504 	/* since we are counting overlaps the final put of the
505 	 * cacheline will occur when the overlap count is 0.
506 	 * active_cacheline_dec_overlap() returns -1 in that case
507 	 */
508 	if (active_cacheline_dec_overlap(cln) < 0)
509 		radix_tree_delete(&dma_active_cacheline, cln);
510 	spin_unlock_irqrestore(&radix_lock, flags);
511 }
512 
513 /*
514  * Dump mappings entries on kernel space for debugging purposes
515  */
debug_dma_dump_mappings(struct device * dev)516 void debug_dma_dump_mappings(struct device *dev)
517 {
518 	int idx;
519 	phys_addr_t cln;
520 
521 	for (idx = 0; idx < HASH_SIZE; idx++) {
522 		struct hash_bucket *bucket = &dma_entry_hash[idx];
523 		struct dma_debug_entry *entry;
524 		unsigned long flags;
525 
526 		spin_lock_irqsave(&bucket->lock, flags);
527 		list_for_each_entry(entry, &bucket->list, list) {
528 			if (!dev || dev == entry->dev) {
529 				cln = to_cacheline_number(entry);
530 				dev_info(entry->dev,
531 					 "%s idx %d P=%pa D=%llx L=%llx cln=%pa %s %s\n",
532 					 type2name[entry->type], idx,
533 					 &entry->paddr, entry->dev_addr,
534 					 entry->size, &cln,
535 					 dir2name[entry->direction],
536 					 maperr2str[entry->map_err_type]);
537 			}
538 		}
539 		spin_unlock_irqrestore(&bucket->lock, flags);
540 
541 		cond_resched();
542 	}
543 }
544 
545 /*
546  * Dump mappings entries on user space via debugfs
547  */
dump_show(struct seq_file * seq,void * v)548 static int dump_show(struct seq_file *seq, void *v)
549 {
550 	int idx;
551 	phys_addr_t cln;
552 
553 	for (idx = 0; idx < HASH_SIZE; idx++) {
554 		struct hash_bucket *bucket = &dma_entry_hash[idx];
555 		struct dma_debug_entry *entry;
556 		unsigned long flags;
557 
558 		spin_lock_irqsave(&bucket->lock, flags);
559 		list_for_each_entry(entry, &bucket->list, list) {
560 			cln = to_cacheline_number(entry);
561 			seq_printf(seq,
562 				   "%s %s %s idx %d P=%pa D=%llx L=%llx cln=%pa %s %s\n",
563 				   dev_driver_string(entry->dev),
564 				   dev_name(entry->dev),
565 				   type2name[entry->type], idx,
566 				   &entry->paddr, entry->dev_addr,
567 				   entry->size, &cln,
568 				   dir2name[entry->direction],
569 				   maperr2str[entry->map_err_type]);
570 		}
571 		spin_unlock_irqrestore(&bucket->lock, flags);
572 	}
573 	return 0;
574 }
575 DEFINE_SHOW_ATTRIBUTE(dump);
576 
577 /*
578  * Wrapper function for adding an entry to the hash.
579  * This function takes care of locking itself.
580  */
add_dma_entry(struct dma_debug_entry * entry,unsigned long attrs)581 static void add_dma_entry(struct dma_debug_entry *entry, unsigned long attrs)
582 {
583 	struct hash_bucket *bucket;
584 	unsigned long flags;
585 	int rc;
586 
587 	bucket = get_hash_bucket(entry, &flags);
588 	hash_bucket_add(bucket, entry);
589 	put_hash_bucket(bucket, flags);
590 
591 	rc = active_cacheline_insert(entry);
592 	if (rc == -ENOMEM) {
593 		pr_err_once("cacheline tracking ENOMEM, dma-debug disabled\n");
594 		global_disable = true;
595 	} else if (rc == -EEXIST && !(attrs & DMA_ATTR_SKIP_CPU_SYNC)) {
596 		err_printk(entry->dev, entry,
597 			"cacheline tracking EEXIST, overlapping mappings aren't supported\n");
598 	}
599 }
600 
dma_debug_create_entries(gfp_t gfp)601 static int dma_debug_create_entries(gfp_t gfp)
602 {
603 	struct dma_debug_entry *entry;
604 	int i;
605 
606 	entry = (void *)get_zeroed_page(gfp);
607 	if (!entry)
608 		return -ENOMEM;
609 
610 	for (i = 0; i < DMA_DEBUG_DYNAMIC_ENTRIES; i++)
611 		list_add_tail(&entry[i].list, &free_entries);
612 
613 	num_free_entries += DMA_DEBUG_DYNAMIC_ENTRIES;
614 	nr_total_entries += DMA_DEBUG_DYNAMIC_ENTRIES;
615 
616 	return 0;
617 }
618 
__dma_entry_alloc(void)619 static struct dma_debug_entry *__dma_entry_alloc(void)
620 {
621 	struct dma_debug_entry *entry;
622 
623 	entry = list_entry(free_entries.next, struct dma_debug_entry, list);
624 	list_del(&entry->list);
625 	memset(entry, 0, sizeof(*entry));
626 
627 	num_free_entries -= 1;
628 	if (num_free_entries < min_free_entries)
629 		min_free_entries = num_free_entries;
630 
631 	return entry;
632 }
633 
634 /*
635  * This should be called outside of free_entries_lock scope to avoid potential
636  * deadlocks with serial consoles that use DMA.
637  */
__dma_entry_alloc_check_leak(u32 nr_entries)638 static void __dma_entry_alloc_check_leak(u32 nr_entries)
639 {
640 	u32 tmp = nr_entries % nr_prealloc_entries;
641 
642 	/* Shout each time we tick over some multiple of the initial pool */
643 	if (tmp < DMA_DEBUG_DYNAMIC_ENTRIES) {
644 		pr_info("dma_debug_entry pool grown to %u (%u00%%)\n",
645 			nr_entries,
646 			(nr_entries / nr_prealloc_entries));
647 	}
648 }
649 
650 /* struct dma_entry allocator
651  *
652  * The next two functions implement the allocator for
653  * struct dma_debug_entries.
654  */
dma_entry_alloc(void)655 static struct dma_debug_entry *dma_entry_alloc(void)
656 {
657 	bool alloc_check_leak = false;
658 	struct dma_debug_entry *entry;
659 	unsigned long flags;
660 	u32 nr_entries;
661 
662 	spin_lock_irqsave(&free_entries_lock, flags);
663 	if (num_free_entries == 0) {
664 		if (dma_debug_create_entries(GFP_ATOMIC)) {
665 			global_disable = true;
666 			spin_unlock_irqrestore(&free_entries_lock, flags);
667 			pr_err("debugging out of memory - disabling\n");
668 			return NULL;
669 		}
670 		alloc_check_leak = true;
671 		nr_entries = nr_total_entries;
672 	}
673 
674 	entry = __dma_entry_alloc();
675 
676 	spin_unlock_irqrestore(&free_entries_lock, flags);
677 
678 	if (alloc_check_leak)
679 		__dma_entry_alloc_check_leak(nr_entries);
680 
681 #ifdef CONFIG_STACKTRACE
682 	entry->stack_len = stack_trace_save(entry->stack_entries,
683 					    ARRAY_SIZE(entry->stack_entries),
684 					    1);
685 #endif
686 	return entry;
687 }
688 
dma_entry_free(struct dma_debug_entry * entry)689 static void dma_entry_free(struct dma_debug_entry *entry)
690 {
691 	unsigned long flags;
692 
693 	active_cacheline_remove(entry);
694 
695 	/*
696 	 * add to beginning of the list - this way the entries are
697 	 * more likely cache hot when they are reallocated.
698 	 */
699 	spin_lock_irqsave(&free_entries_lock, flags);
700 	list_add(&entry->list, &free_entries);
701 	num_free_entries += 1;
702 	spin_unlock_irqrestore(&free_entries_lock, flags);
703 }
704 
705 /*
706  * DMA-API debugging init code
707  *
708  * The init code does two things:
709  *   1. Initialize core data structures
710  *   2. Preallocate a given number of dma_debug_entry structs
711  */
712 
filter_read(struct file * file,char __user * user_buf,size_t count,loff_t * ppos)713 static ssize_t filter_read(struct file *file, char __user *user_buf,
714 			   size_t count, loff_t *ppos)
715 {
716 	char buf[NAME_MAX_LEN + 1];
717 	unsigned long flags;
718 	int len;
719 
720 	if (!current_driver_name[0])
721 		return 0;
722 
723 	/*
724 	 * We can't copy to userspace directly because current_driver_name can
725 	 * only be read under the driver_name_lock with irqs disabled. So
726 	 * create a temporary copy first.
727 	 */
728 	read_lock_irqsave(&driver_name_lock, flags);
729 	len = scnprintf(buf, NAME_MAX_LEN + 1, "%s\n", current_driver_name);
730 	read_unlock_irqrestore(&driver_name_lock, flags);
731 
732 	return simple_read_from_buffer(user_buf, count, ppos, buf, len);
733 }
734 
filter_write(struct file * file,const char __user * userbuf,size_t count,loff_t * ppos)735 static ssize_t filter_write(struct file *file, const char __user *userbuf,
736 			    size_t count, loff_t *ppos)
737 {
738 	char buf[NAME_MAX_LEN];
739 	unsigned long flags;
740 	size_t len;
741 	int i;
742 
743 	/*
744 	 * We can't copy from userspace directly. Access to
745 	 * current_driver_name is protected with a write_lock with irqs
746 	 * disabled. Since copy_from_user can fault and may sleep we
747 	 * need to copy to temporary buffer first
748 	 */
749 	len = min(count, (size_t)(NAME_MAX_LEN - 1));
750 	if (copy_from_user(buf, userbuf, len))
751 		return -EFAULT;
752 
753 	buf[len] = 0;
754 
755 	write_lock_irqsave(&driver_name_lock, flags);
756 
757 	/*
758 	 * Now handle the string we got from userspace very carefully.
759 	 * The rules are:
760 	 *         - only use the first token we got
761 	 *         - token delimiter is everything looking like a space
762 	 *           character (' ', '\n', '\t' ...)
763 	 *
764 	 */
765 	if (!isalnum(buf[0])) {
766 		/*
767 		 * If the first character userspace gave us is not
768 		 * alphanumerical then assume the filter should be
769 		 * switched off.
770 		 */
771 		if (current_driver_name[0])
772 			pr_info("switching off dma-debug driver filter\n");
773 		current_driver_name[0] = 0;
774 		current_driver = NULL;
775 		goto out_unlock;
776 	}
777 
778 	/*
779 	 * Now parse out the first token and use it as the name for the
780 	 * driver to filter for.
781 	 */
782 	for (i = 0; i < NAME_MAX_LEN - 1; ++i) {
783 		current_driver_name[i] = buf[i];
784 		if (isspace(buf[i]) || buf[i] == ' ' || buf[i] == 0)
785 			break;
786 	}
787 	current_driver_name[i] = 0;
788 	current_driver = NULL;
789 
790 	pr_info("enable driver filter for driver [%s]\n",
791 		current_driver_name);
792 
793 out_unlock:
794 	write_unlock_irqrestore(&driver_name_lock, flags);
795 
796 	return count;
797 }
798 
799 static const struct file_operations filter_fops = {
800 	.read  = filter_read,
801 	.write = filter_write,
802 	.llseek = default_llseek,
803 };
804 
dma_debug_fs_init(void)805 static int __init dma_debug_fs_init(void)
806 {
807 	struct dentry *dentry = debugfs_create_dir("dma-api", NULL);
808 
809 	debugfs_create_bool("disabled", 0444, dentry, &global_disable);
810 	debugfs_create_u32("error_count", 0444, dentry, &error_count);
811 	debugfs_create_u32("all_errors", 0644, dentry, &show_all_errors);
812 	debugfs_create_u32("num_errors", 0644, dentry, &show_num_errors);
813 	debugfs_create_u32("num_free_entries", 0444, dentry, &num_free_entries);
814 	debugfs_create_u32("min_free_entries", 0444, dentry, &min_free_entries);
815 	debugfs_create_u32("nr_total_entries", 0444, dentry, &nr_total_entries);
816 	debugfs_create_file("driver_filter", 0644, dentry, NULL, &filter_fops);
817 	debugfs_create_file("dump", 0444, dentry, NULL, &dump_fops);
818 
819 	return 0;
820 }
821 core_initcall_sync(dma_debug_fs_init);
822 
device_dma_allocations(struct device * dev,struct dma_debug_entry ** out_entry)823 static int device_dma_allocations(struct device *dev, struct dma_debug_entry **out_entry)
824 {
825 	struct dma_debug_entry *entry;
826 	unsigned long flags;
827 	int count = 0, i;
828 
829 	for (i = 0; i < HASH_SIZE; ++i) {
830 		spin_lock_irqsave(&dma_entry_hash[i].lock, flags);
831 		list_for_each_entry(entry, &dma_entry_hash[i].list, list) {
832 			if (entry->dev == dev) {
833 				count += 1;
834 				*out_entry = entry;
835 			}
836 		}
837 		spin_unlock_irqrestore(&dma_entry_hash[i].lock, flags);
838 	}
839 
840 	return count;
841 }
842 
dma_debug_device_change(struct notifier_block * nb,unsigned long action,void * data)843 static int dma_debug_device_change(struct notifier_block *nb, unsigned long action, void *data)
844 {
845 	struct device *dev = data;
846 	struct dma_debug_entry *entry;
847 	int count;
848 
849 	if (dma_debug_disabled())
850 		return 0;
851 
852 	switch (action) {
853 	case BUS_NOTIFY_UNBOUND_DRIVER:
854 		count = device_dma_allocations(dev, &entry);
855 		if (count == 0)
856 			break;
857 		err_printk(dev, entry, "device driver has pending "
858 				"DMA allocations while released from device "
859 				"[count=%d]\n"
860 				"One of leaked entries details: "
861 				"[device address=0x%016llx] [size=%llu bytes] "
862 				"[mapped with %s] [mapped as %s]\n",
863 			count, entry->dev_addr, entry->size,
864 			dir2name[entry->direction], type2name[entry->type]);
865 		break;
866 	default:
867 		break;
868 	}
869 
870 	return 0;
871 }
872 
dma_debug_add_bus(const struct bus_type * bus)873 void dma_debug_add_bus(const struct bus_type *bus)
874 {
875 	struct notifier_block *nb;
876 
877 	if (dma_debug_disabled())
878 		return;
879 
880 	nb = kzalloc(sizeof(struct notifier_block), GFP_KERNEL);
881 	if (nb == NULL) {
882 		pr_err("dma_debug_add_bus: out of memory\n");
883 		return;
884 	}
885 
886 	nb->notifier_call = dma_debug_device_change;
887 
888 	bus_register_notifier(bus, nb);
889 }
890 
dma_debug_init(void)891 static int dma_debug_init(void)
892 {
893 	int i, nr_pages;
894 
895 	/* Do not use dma_debug_initialized here, since we really want to be
896 	 * called to set dma_debug_initialized
897 	 */
898 	if (global_disable)
899 		return 0;
900 
901 	for (i = 0; i < HASH_SIZE; ++i) {
902 		INIT_LIST_HEAD(&dma_entry_hash[i].list);
903 		spin_lock_init(&dma_entry_hash[i].lock);
904 	}
905 
906 	nr_pages = DIV_ROUND_UP(nr_prealloc_entries, DMA_DEBUG_DYNAMIC_ENTRIES);
907 	for (i = 0; i < nr_pages; ++i)
908 		dma_debug_create_entries(GFP_KERNEL);
909 	if (num_free_entries >= nr_prealloc_entries) {
910 		pr_info("preallocated %d debug entries\n", nr_total_entries);
911 	} else if (num_free_entries > 0) {
912 		pr_warn("%d debug entries requested but only %d allocated\n",
913 			nr_prealloc_entries, nr_total_entries);
914 	} else {
915 		pr_err("debugging out of memory error - disabled\n");
916 		global_disable = true;
917 
918 		return 0;
919 	}
920 	min_free_entries = num_free_entries;
921 
922 	dma_debug_initialized = true;
923 
924 	pr_info("debugging enabled by kernel config\n");
925 	return 0;
926 }
927 core_initcall(dma_debug_init);
928 
dma_debug_cmdline(char * str)929 static __init int dma_debug_cmdline(char *str)
930 {
931 	if (!str)
932 		return -EINVAL;
933 
934 	if (strncmp(str, "off", 3) == 0) {
935 		pr_info("debugging disabled on kernel command line\n");
936 		global_disable = true;
937 	}
938 
939 	return 1;
940 }
941 
dma_debug_entries_cmdline(char * str)942 static __init int dma_debug_entries_cmdline(char *str)
943 {
944 	if (!str)
945 		return -EINVAL;
946 	if (!get_option(&str, &nr_prealloc_entries))
947 		nr_prealloc_entries = PREALLOC_DMA_DEBUG_ENTRIES;
948 	return 1;
949 }
950 
951 __setup("dma_debug=", dma_debug_cmdline);
952 __setup("dma_debug_entries=", dma_debug_entries_cmdline);
953 
check_unmap(struct dma_debug_entry * ref)954 static void check_unmap(struct dma_debug_entry *ref)
955 {
956 	struct dma_debug_entry *entry;
957 	struct hash_bucket *bucket;
958 	unsigned long flags;
959 
960 	bucket = get_hash_bucket(ref, &flags);
961 	entry = bucket_find_exact(bucket, ref);
962 
963 	if (!entry) {
964 		/* must drop lock before calling dma_mapping_error */
965 		put_hash_bucket(bucket, flags);
966 
967 		if (dma_mapping_error(ref->dev, ref->dev_addr)) {
968 			err_printk(ref->dev, NULL,
969 				   "device driver tries to free an "
970 				   "invalid DMA memory address\n");
971 		} else {
972 			err_printk(ref->dev, NULL,
973 				   "device driver tries to free DMA "
974 				   "memory it has not allocated [device "
975 				   "address=0x%016llx] [size=%llu bytes]\n",
976 				   ref->dev_addr, ref->size);
977 		}
978 		return;
979 	}
980 
981 	if (ref->size != entry->size) {
982 		err_printk(ref->dev, entry, "device driver frees "
983 			   "DMA memory with different size "
984 			   "[device address=0x%016llx] [map size=%llu bytes] "
985 			   "[unmap size=%llu bytes]\n",
986 			   ref->dev_addr, entry->size, ref->size);
987 	}
988 
989 	if (ref->type != entry->type) {
990 		err_printk(ref->dev, entry, "device driver frees "
991 			   "DMA memory with wrong function "
992 			   "[device address=0x%016llx] [size=%llu bytes] "
993 			   "[mapped as %s] [unmapped as %s]\n",
994 			   ref->dev_addr, ref->size,
995 			   type2name[entry->type], type2name[ref->type]);
996 	} else if (entry->type == dma_debug_coherent &&
997 		   ref->paddr != entry->paddr) {
998 		err_printk(ref->dev, entry, "device driver frees "
999 			   "DMA memory with different CPU address "
1000 			   "[device address=0x%016llx] [size=%llu bytes] "
1001 			   "[cpu alloc address=0x%pa] "
1002 			   "[cpu free address=0x%pa]",
1003 			   ref->dev_addr, ref->size,
1004 			   &entry->paddr,
1005 			   &ref->paddr);
1006 	}
1007 
1008 	if (ref->sg_call_ents && ref->type == dma_debug_sg &&
1009 	    ref->sg_call_ents != entry->sg_call_ents) {
1010 		err_printk(ref->dev, entry, "device driver frees "
1011 			   "DMA sg list with different entry count "
1012 			   "[map count=%d] [unmap count=%d]\n",
1013 			   entry->sg_call_ents, ref->sg_call_ents);
1014 	}
1015 
1016 	/*
1017 	 * This may be no bug in reality - but most implementations of the
1018 	 * DMA API don't handle this properly, so check for it here
1019 	 */
1020 	if (ref->direction != entry->direction) {
1021 		err_printk(ref->dev, entry, "device driver frees "
1022 			   "DMA memory with different direction "
1023 			   "[device address=0x%016llx] [size=%llu bytes] "
1024 			   "[mapped with %s] [unmapped with %s]\n",
1025 			   ref->dev_addr, ref->size,
1026 			   dir2name[entry->direction],
1027 			   dir2name[ref->direction]);
1028 	}
1029 
1030 	/*
1031 	 * Drivers should use dma_mapping_error() to check the returned
1032 	 * addresses of dma_map_single() and dma_map_page().
1033 	 * If not, print this warning message. See Documentation/core-api/dma-api.rst.
1034 	 */
1035 	if (entry->map_err_type == MAP_ERR_NOT_CHECKED) {
1036 		err_printk(ref->dev, entry,
1037 			   "device driver failed to check map error"
1038 			   "[device address=0x%016llx] [size=%llu bytes] "
1039 			   "[mapped as %s]",
1040 			   ref->dev_addr, ref->size,
1041 			   type2name[entry->type]);
1042 	}
1043 
1044 	hash_bucket_del(entry);
1045 	put_hash_bucket(bucket, flags);
1046 
1047 	/*
1048 	 * Free the entry outside of bucket_lock to avoid ABBA deadlocks
1049 	 * between that and radix_lock.
1050 	 */
1051 	dma_entry_free(entry);
1052 }
1053 
check_for_stack(struct device * dev,struct page * page,size_t offset)1054 static void check_for_stack(struct device *dev,
1055 			    struct page *page, size_t offset)
1056 {
1057 	void *addr;
1058 	struct vm_struct *stack_vm_area = task_stack_vm_area(current);
1059 
1060 	if (!stack_vm_area) {
1061 		/* Stack is direct-mapped. */
1062 		if (PageHighMem(page))
1063 			return;
1064 		addr = page_address(page) + offset;
1065 		if (object_is_on_stack(addr))
1066 			err_printk(dev, NULL, "device driver maps memory from stack [addr=%p]\n", addr);
1067 	} else {
1068 		/* Stack is vmalloced. */
1069 		int i;
1070 
1071 		for (i = 0; i < stack_vm_area->nr_pages; i++) {
1072 			if (page != stack_vm_area->pages[i])
1073 				continue;
1074 
1075 			addr = (u8 *)current->stack + i * PAGE_SIZE + offset;
1076 			err_printk(dev, NULL, "device driver maps memory from stack [probable addr=%p]\n", addr);
1077 			break;
1078 		}
1079 	}
1080 }
1081 
check_for_illegal_area(struct device * dev,void * addr,unsigned long len)1082 static void check_for_illegal_area(struct device *dev, void *addr, unsigned long len)
1083 {
1084 	if (memory_intersects(_stext, _etext, addr, len) ||
1085 	    memory_intersects(__start_rodata, __end_rodata, addr, len))
1086 		err_printk(dev, NULL, "device driver maps memory from kernel text or rodata [addr=%p] [len=%lu]\n", addr, len);
1087 }
1088 
check_sync(struct device * dev,struct dma_debug_entry * ref,bool to_cpu)1089 static void check_sync(struct device *dev,
1090 		       struct dma_debug_entry *ref,
1091 		       bool to_cpu)
1092 {
1093 	struct dma_debug_entry *entry;
1094 	struct hash_bucket *bucket;
1095 	unsigned long flags;
1096 
1097 	bucket = get_hash_bucket(ref, &flags);
1098 
1099 	entry = bucket_find_contain(&bucket, ref, &flags);
1100 
1101 	if (!entry) {
1102 		err_printk(dev, NULL, "device driver tries "
1103 				"to sync DMA memory it has not allocated "
1104 				"[device address=0x%016llx] [size=%llu bytes]\n",
1105 				(unsigned long long)ref->dev_addr, ref->size);
1106 		goto out;
1107 	}
1108 
1109 	if (ref->size > entry->size) {
1110 		err_printk(dev, entry, "device driver syncs"
1111 				" DMA memory outside allocated range "
1112 				"[device address=0x%016llx] "
1113 				"[allocation size=%llu bytes] "
1114 				"[sync offset+size=%llu]\n",
1115 				entry->dev_addr, entry->size,
1116 				ref->size);
1117 	}
1118 
1119 	if (entry->direction == DMA_BIDIRECTIONAL)
1120 		goto out;
1121 
1122 	if (ref->direction != entry->direction) {
1123 		err_printk(dev, entry, "device driver syncs "
1124 				"DMA memory with different direction "
1125 				"[device address=0x%016llx] [size=%llu bytes] "
1126 				"[mapped with %s] [synced with %s]\n",
1127 				(unsigned long long)ref->dev_addr, entry->size,
1128 				dir2name[entry->direction],
1129 				dir2name[ref->direction]);
1130 	}
1131 
1132 	if (to_cpu && !(entry->direction == DMA_FROM_DEVICE) &&
1133 		      !(ref->direction == DMA_TO_DEVICE))
1134 		err_printk(dev, entry, "device driver syncs "
1135 				"device read-only DMA memory for cpu "
1136 				"[device address=0x%016llx] [size=%llu bytes] "
1137 				"[mapped with %s] [synced with %s]\n",
1138 				(unsigned long long)ref->dev_addr, entry->size,
1139 				dir2name[entry->direction],
1140 				dir2name[ref->direction]);
1141 
1142 	if (!to_cpu && !(entry->direction == DMA_TO_DEVICE) &&
1143 		       !(ref->direction == DMA_FROM_DEVICE))
1144 		err_printk(dev, entry, "device driver syncs "
1145 				"device write-only DMA memory to device "
1146 				"[device address=0x%016llx] [size=%llu bytes] "
1147 				"[mapped with %s] [synced with %s]\n",
1148 				(unsigned long long)ref->dev_addr, entry->size,
1149 				dir2name[entry->direction],
1150 				dir2name[ref->direction]);
1151 
1152 	if (ref->sg_call_ents && ref->type == dma_debug_sg &&
1153 	    ref->sg_call_ents != entry->sg_call_ents) {
1154 		err_printk(ref->dev, entry, "device driver syncs "
1155 			   "DMA sg list with different entry count "
1156 			   "[map count=%d] [sync count=%d]\n",
1157 			   entry->sg_call_ents, ref->sg_call_ents);
1158 	}
1159 
1160 out:
1161 	put_hash_bucket(bucket, flags);
1162 }
1163 
check_sg_segment(struct device * dev,struct scatterlist * sg)1164 static void check_sg_segment(struct device *dev, struct scatterlist *sg)
1165 {
1166 	unsigned int max_seg = dma_get_max_seg_size(dev);
1167 	u64 start, end, boundary = dma_get_seg_boundary(dev);
1168 
1169 	/*
1170 	 * Either the driver forgot to set dma_parms appropriately, or
1171 	 * whoever generated the list forgot to check them.
1172 	 */
1173 	if (sg->length > max_seg)
1174 		err_printk(dev, NULL, "mapping sg segment longer than device claims to support [len=%u] [max=%u]\n",
1175 			   sg->length, max_seg);
1176 	/*
1177 	 * In some cases this could potentially be the DMA API
1178 	 * implementation's fault, but it would usually imply that
1179 	 * the scatterlist was built inappropriately to begin with.
1180 	 */
1181 	start = sg_dma_address(sg);
1182 	end = start + sg_dma_len(sg) - 1;
1183 	if ((start ^ end) & ~boundary)
1184 		err_printk(dev, NULL, "mapping sg segment across boundary [start=0x%016llx] [end=0x%016llx] [boundary=0x%016llx]\n",
1185 			   start, end, boundary);
1186 }
1187 
debug_dma_map_single(struct device * dev,const void * addr,unsigned long len)1188 void debug_dma_map_single(struct device *dev, const void *addr,
1189 			    unsigned long len)
1190 {
1191 	if (unlikely(dma_debug_disabled()))
1192 		return;
1193 
1194 	if (!virt_addr_valid(addr))
1195 		err_printk(dev, NULL, "device driver maps memory from invalid area [addr=%p] [len=%lu]\n",
1196 			   addr, len);
1197 
1198 	if (is_vmalloc_addr(addr))
1199 		err_printk(dev, NULL, "device driver maps memory from vmalloc area [addr=%p] [len=%lu]\n",
1200 			   addr, len);
1201 }
1202 EXPORT_SYMBOL(debug_dma_map_single);
1203 
debug_dma_map_page(struct device * dev,struct page * page,size_t offset,size_t size,int direction,dma_addr_t dma_addr,unsigned long attrs)1204 void debug_dma_map_page(struct device *dev, struct page *page, size_t offset,
1205 			size_t size, int direction, dma_addr_t dma_addr,
1206 			unsigned long attrs)
1207 {
1208 	struct dma_debug_entry *entry;
1209 
1210 	if (unlikely(dma_debug_disabled()))
1211 		return;
1212 
1213 	if (dma_mapping_error(dev, dma_addr))
1214 		return;
1215 
1216 	entry = dma_entry_alloc();
1217 	if (!entry)
1218 		return;
1219 
1220 	entry->dev       = dev;
1221 	entry->type      = dma_debug_single;
1222 	entry->paddr	 = page_to_phys(page) + offset;
1223 	entry->dev_addr  = dma_addr;
1224 	entry->size      = size;
1225 	entry->direction = direction;
1226 	entry->map_err_type = MAP_ERR_NOT_CHECKED;
1227 
1228 	check_for_stack(dev, page, offset);
1229 
1230 	if (!PageHighMem(page)) {
1231 		void *addr = page_address(page) + offset;
1232 
1233 		check_for_illegal_area(dev, addr, size);
1234 	}
1235 
1236 	add_dma_entry(entry, attrs);
1237 }
1238 
debug_dma_mapping_error(struct device * dev,dma_addr_t dma_addr)1239 void debug_dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
1240 {
1241 	struct dma_debug_entry ref;
1242 	struct dma_debug_entry *entry;
1243 	struct hash_bucket *bucket;
1244 	unsigned long flags;
1245 
1246 	if (unlikely(dma_debug_disabled()))
1247 		return;
1248 
1249 	ref.dev = dev;
1250 	ref.dev_addr = dma_addr;
1251 	bucket = get_hash_bucket(&ref, &flags);
1252 
1253 	list_for_each_entry(entry, &bucket->list, list) {
1254 		if (!exact_match(&ref, entry))
1255 			continue;
1256 
1257 		/*
1258 		 * The same physical address can be mapped multiple
1259 		 * times. Without a hardware IOMMU this results in the
1260 		 * same device addresses being put into the dma-debug
1261 		 * hash multiple times too. This can result in false
1262 		 * positives being reported. Therefore we implement a
1263 		 * best-fit algorithm here which updates the first entry
1264 		 * from the hash which fits the reference value and is
1265 		 * not currently listed as being checked.
1266 		 */
1267 		if (entry->map_err_type == MAP_ERR_NOT_CHECKED) {
1268 			entry->map_err_type = MAP_ERR_CHECKED;
1269 			break;
1270 		}
1271 	}
1272 
1273 	put_hash_bucket(bucket, flags);
1274 }
1275 EXPORT_SYMBOL(debug_dma_mapping_error);
1276 
debug_dma_unmap_page(struct device * dev,dma_addr_t dma_addr,size_t size,int direction)1277 void debug_dma_unmap_page(struct device *dev, dma_addr_t dma_addr,
1278 			  size_t size, int direction)
1279 {
1280 	struct dma_debug_entry ref = {
1281 		.type           = dma_debug_single,
1282 		.dev            = dev,
1283 		.dev_addr       = dma_addr,
1284 		.size           = size,
1285 		.direction      = direction,
1286 	};
1287 
1288 	if (unlikely(dma_debug_disabled()))
1289 		return;
1290 	check_unmap(&ref);
1291 }
1292 
debug_dma_map_sg(struct device * dev,struct scatterlist * sg,int nents,int mapped_ents,int direction,unsigned long attrs)1293 void debug_dma_map_sg(struct device *dev, struct scatterlist *sg,
1294 		      int nents, int mapped_ents, int direction,
1295 		      unsigned long attrs)
1296 {
1297 	struct dma_debug_entry *entry;
1298 	struct scatterlist *s;
1299 	int i;
1300 
1301 	if (unlikely(dma_debug_disabled()))
1302 		return;
1303 
1304 	for_each_sg(sg, s, nents, i) {
1305 		check_for_stack(dev, sg_page(s), s->offset);
1306 		if (!PageHighMem(sg_page(s)))
1307 			check_for_illegal_area(dev, sg_virt(s), s->length);
1308 	}
1309 
1310 	for_each_sg(sg, s, mapped_ents, i) {
1311 		entry = dma_entry_alloc();
1312 		if (!entry)
1313 			return;
1314 
1315 		entry->type           = dma_debug_sg;
1316 		entry->dev            = dev;
1317 		entry->paddr	      = sg_phys(s);
1318 		entry->size           = sg_dma_len(s);
1319 		entry->dev_addr       = sg_dma_address(s);
1320 		entry->direction      = direction;
1321 		entry->sg_call_ents   = nents;
1322 		entry->sg_mapped_ents = mapped_ents;
1323 
1324 		check_sg_segment(dev, s);
1325 
1326 		add_dma_entry(entry, attrs);
1327 	}
1328 }
1329 
get_nr_mapped_entries(struct device * dev,struct dma_debug_entry * ref)1330 static int get_nr_mapped_entries(struct device *dev,
1331 				 struct dma_debug_entry *ref)
1332 {
1333 	struct dma_debug_entry *entry;
1334 	struct hash_bucket *bucket;
1335 	unsigned long flags;
1336 	int mapped_ents;
1337 
1338 	bucket       = get_hash_bucket(ref, &flags);
1339 	entry        = bucket_find_exact(bucket, ref);
1340 	mapped_ents  = 0;
1341 
1342 	if (entry)
1343 		mapped_ents = entry->sg_mapped_ents;
1344 	put_hash_bucket(bucket, flags);
1345 
1346 	return mapped_ents;
1347 }
1348 
debug_dma_unmap_sg(struct device * dev,struct scatterlist * sglist,int nelems,int dir)1349 void debug_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
1350 			int nelems, int dir)
1351 {
1352 	struct scatterlist *s;
1353 	int mapped_ents = 0, i;
1354 
1355 	if (unlikely(dma_debug_disabled()))
1356 		return;
1357 
1358 	for_each_sg(sglist, s, nelems, i) {
1359 
1360 		struct dma_debug_entry ref = {
1361 			.type           = dma_debug_sg,
1362 			.dev            = dev,
1363 			.paddr		= sg_phys(s),
1364 			.dev_addr       = sg_dma_address(s),
1365 			.size           = sg_dma_len(s),
1366 			.direction      = dir,
1367 			.sg_call_ents   = nelems,
1368 		};
1369 
1370 		if (mapped_ents && i >= mapped_ents)
1371 			break;
1372 
1373 		if (!i)
1374 			mapped_ents = get_nr_mapped_entries(dev, &ref);
1375 
1376 		check_unmap(&ref);
1377 	}
1378 }
1379 
virt_to_paddr(void * virt)1380 static phys_addr_t virt_to_paddr(void *virt)
1381 {
1382 	struct page *page;
1383 
1384 	if (is_vmalloc_addr(virt))
1385 		page = vmalloc_to_page(virt);
1386 	else
1387 		page = virt_to_page(virt);
1388 
1389 	return page_to_phys(page) + offset_in_page(virt);
1390 }
1391 
debug_dma_alloc_coherent(struct device * dev,size_t size,dma_addr_t dma_addr,void * virt,unsigned long attrs)1392 void debug_dma_alloc_coherent(struct device *dev, size_t size,
1393 			      dma_addr_t dma_addr, void *virt,
1394 			      unsigned long attrs)
1395 {
1396 	struct dma_debug_entry *entry;
1397 
1398 	if (unlikely(dma_debug_disabled()))
1399 		return;
1400 
1401 	if (unlikely(virt == NULL))
1402 		return;
1403 
1404 	/* handle vmalloc and linear addresses */
1405 	if (!is_vmalloc_addr(virt) && !virt_addr_valid(virt))
1406 		return;
1407 
1408 	entry = dma_entry_alloc();
1409 	if (!entry)
1410 		return;
1411 
1412 	entry->type      = dma_debug_coherent;
1413 	entry->dev       = dev;
1414 	entry->paddr	 = virt_to_paddr(virt);
1415 	entry->size      = size;
1416 	entry->dev_addr  = dma_addr;
1417 	entry->direction = DMA_BIDIRECTIONAL;
1418 
1419 	add_dma_entry(entry, attrs);
1420 }
1421 
debug_dma_free_coherent(struct device * dev,size_t size,void * virt,dma_addr_t dma_addr)1422 void debug_dma_free_coherent(struct device *dev, size_t size,
1423 			 void *virt, dma_addr_t dma_addr)
1424 {
1425 	struct dma_debug_entry ref = {
1426 		.type           = dma_debug_coherent,
1427 		.dev            = dev,
1428 		.dev_addr       = dma_addr,
1429 		.size           = size,
1430 		.direction      = DMA_BIDIRECTIONAL,
1431 	};
1432 
1433 	/* handle vmalloc and linear addresses */
1434 	if (!is_vmalloc_addr(virt) && !virt_addr_valid(virt))
1435 		return;
1436 
1437 	ref.paddr = virt_to_paddr(virt);
1438 
1439 	if (unlikely(dma_debug_disabled()))
1440 		return;
1441 
1442 	check_unmap(&ref);
1443 }
1444 
debug_dma_map_resource(struct device * dev,phys_addr_t addr,size_t size,int direction,dma_addr_t dma_addr,unsigned long attrs)1445 void debug_dma_map_resource(struct device *dev, phys_addr_t addr, size_t size,
1446 			    int direction, dma_addr_t dma_addr,
1447 			    unsigned long attrs)
1448 {
1449 	struct dma_debug_entry *entry;
1450 
1451 	if (unlikely(dma_debug_disabled()))
1452 		return;
1453 
1454 	entry = dma_entry_alloc();
1455 	if (!entry)
1456 		return;
1457 
1458 	entry->type		= dma_debug_resource;
1459 	entry->dev		= dev;
1460 	entry->paddr		= addr;
1461 	entry->size		= size;
1462 	entry->dev_addr		= dma_addr;
1463 	entry->direction	= direction;
1464 	entry->map_err_type	= MAP_ERR_NOT_CHECKED;
1465 
1466 	add_dma_entry(entry, attrs);
1467 }
1468 
debug_dma_unmap_resource(struct device * dev,dma_addr_t dma_addr,size_t size,int direction)1469 void debug_dma_unmap_resource(struct device *dev, dma_addr_t dma_addr,
1470 			      size_t size, int direction)
1471 {
1472 	struct dma_debug_entry ref = {
1473 		.type           = dma_debug_resource,
1474 		.dev            = dev,
1475 		.dev_addr       = dma_addr,
1476 		.size           = size,
1477 		.direction      = direction,
1478 	};
1479 
1480 	if (unlikely(dma_debug_disabled()))
1481 		return;
1482 
1483 	check_unmap(&ref);
1484 }
1485 
debug_dma_sync_single_for_cpu(struct device * dev,dma_addr_t dma_handle,size_t size,int direction)1486 void debug_dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_handle,
1487 				   size_t size, int direction)
1488 {
1489 	struct dma_debug_entry ref;
1490 
1491 	if (unlikely(dma_debug_disabled()))
1492 		return;
1493 
1494 	ref.type         = dma_debug_single;
1495 	ref.dev          = dev;
1496 	ref.dev_addr     = dma_handle;
1497 	ref.size         = size;
1498 	ref.direction    = direction;
1499 	ref.sg_call_ents = 0;
1500 
1501 	check_sync(dev, &ref, true);
1502 }
1503 
debug_dma_sync_single_for_device(struct device * dev,dma_addr_t dma_handle,size_t size,int direction)1504 void debug_dma_sync_single_for_device(struct device *dev,
1505 				      dma_addr_t dma_handle, size_t size,
1506 				      int direction)
1507 {
1508 	struct dma_debug_entry ref;
1509 
1510 	if (unlikely(dma_debug_disabled()))
1511 		return;
1512 
1513 	ref.type         = dma_debug_single;
1514 	ref.dev          = dev;
1515 	ref.dev_addr     = dma_handle;
1516 	ref.size         = size;
1517 	ref.direction    = direction;
1518 	ref.sg_call_ents = 0;
1519 
1520 	check_sync(dev, &ref, false);
1521 }
1522 
debug_dma_sync_sg_for_cpu(struct device * dev,struct scatterlist * sg,int nelems,int direction)1523 void debug_dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
1524 			       int nelems, int direction)
1525 {
1526 	struct scatterlist *s;
1527 	int mapped_ents = 0, i;
1528 
1529 	if (unlikely(dma_debug_disabled()))
1530 		return;
1531 
1532 	for_each_sg(sg, s, nelems, i) {
1533 
1534 		struct dma_debug_entry ref = {
1535 			.type           = dma_debug_sg,
1536 			.dev            = dev,
1537 			.paddr		= sg_phys(s),
1538 			.dev_addr       = sg_dma_address(s),
1539 			.size           = sg_dma_len(s),
1540 			.direction      = direction,
1541 			.sg_call_ents   = nelems,
1542 		};
1543 
1544 		if (!i)
1545 			mapped_ents = get_nr_mapped_entries(dev, &ref);
1546 
1547 		if (i >= mapped_ents)
1548 			break;
1549 
1550 		check_sync(dev, &ref, true);
1551 	}
1552 }
1553 
debug_dma_sync_sg_for_device(struct device * dev,struct scatterlist * sg,int nelems,int direction)1554 void debug_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
1555 				  int nelems, int direction)
1556 {
1557 	struct scatterlist *s;
1558 	int mapped_ents = 0, i;
1559 
1560 	if (unlikely(dma_debug_disabled()))
1561 		return;
1562 
1563 	for_each_sg(sg, s, nelems, i) {
1564 
1565 		struct dma_debug_entry ref = {
1566 			.type           = dma_debug_sg,
1567 			.dev            = dev,
1568 			.paddr		= sg_phys(sg),
1569 			.dev_addr       = sg_dma_address(s),
1570 			.size           = sg_dma_len(s),
1571 			.direction      = direction,
1572 			.sg_call_ents   = nelems,
1573 		};
1574 		if (!i)
1575 			mapped_ents = get_nr_mapped_entries(dev, &ref);
1576 
1577 		if (i >= mapped_ents)
1578 			break;
1579 
1580 		check_sync(dev, &ref, false);
1581 	}
1582 }
1583 
dma_debug_driver_setup(char * str)1584 static int __init dma_debug_driver_setup(char *str)
1585 {
1586 	int i;
1587 
1588 	for (i = 0; i < NAME_MAX_LEN - 1; ++i, ++str) {
1589 		current_driver_name[i] = *str;
1590 		if (*str == 0)
1591 			break;
1592 	}
1593 
1594 	if (current_driver_name[0])
1595 		pr_info("enable driver filter for driver [%s]\n",
1596 			current_driver_name);
1597 
1598 
1599 	return 1;
1600 }
1601 __setup("dma_debug_driver=", dma_debug_driver_setup);
1602