Root/lib/dma-debug.c

1/*
2 * Copyright (C) 2008 Advanced Micro Devices, Inc.
3 *
4 * Author: Joerg Roedel <joerg.roedel@amd.com>
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms of the GNU General Public License version 2 as published
8 * by the Free Software Foundation.
9 *
10 * This program is distributed in the hope that it will be useful,
11 * but WITHOUT ANY WARRANTY; without even the implied warranty of
12 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
13 * GNU General Public License for more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program; if not, write to the Free Software
17 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
18 */
19
20#include <linux/scatterlist.h>
21#include <linux/dma-mapping.h>
22#include <linux/stacktrace.h>
23#include <linux/dma-debug.h>
24#include <linux/spinlock.h>
25#include <linux/debugfs.h>
26#include <linux/uaccess.h>
27#include <linux/device.h>
28#include <linux/types.h>
29#include <linux/sched.h>
30#include <linux/ctype.h>
31#include <linux/list.h>
32#include <linux/slab.h>
33
34#include <asm/sections.h>
35
36#define HASH_SIZE 1024ULL
37#define HASH_FN_SHIFT 13
38#define HASH_FN_MASK (HASH_SIZE - 1)
39
40enum {
41    dma_debug_single,
42    dma_debug_page,
43    dma_debug_sg,
44    dma_debug_coherent,
45};
46
47#define DMA_DEBUG_STACKTRACE_ENTRIES 5
48
49struct dma_debug_entry {
50    struct list_head list;
51    struct device *dev;
52    int type;
53    phys_addr_t paddr;
54    u64 dev_addr;
55    u64 size;
56    int direction;
57    int sg_call_ents;
58    int sg_mapped_ents;
59#ifdef CONFIG_STACKTRACE
60    struct stack_trace stacktrace;
61    unsigned long st_entries[DMA_DEBUG_STACKTRACE_ENTRIES];
62#endif
63};
64
65struct hash_bucket {
66    struct list_head list;
67    spinlock_t lock;
68} ____cacheline_aligned_in_smp;
69
70/* Hash list to save the allocated dma addresses */
71static struct hash_bucket dma_entry_hash[HASH_SIZE];
72/* List of pre-allocated dma_debug_entry's */
73static LIST_HEAD(free_entries);
74/* Lock for the list above */
75static DEFINE_SPINLOCK(free_entries_lock);
76
77/* Global disable flag - will be set in case of an error */
78static bool global_disable __read_mostly;
79
80/* Global error count */
81static u32 error_count;
82
83/* Global error show enable*/
84static u32 show_all_errors __read_mostly;
85/* Number of errors to show */
86static u32 show_num_errors = 1;
87
88static u32 num_free_entries;
89static u32 min_free_entries;
90static u32 nr_total_entries;
91
92/* number of preallocated entries requested by kernel cmdline */
93static u32 req_entries;
94
95/* debugfs dentry's for the stuff above */
96static struct dentry *dma_debug_dent __read_mostly;
97static struct dentry *global_disable_dent __read_mostly;
98static struct dentry *error_count_dent __read_mostly;
99static struct dentry *show_all_errors_dent __read_mostly;
100static struct dentry *show_num_errors_dent __read_mostly;
101static struct dentry *num_free_entries_dent __read_mostly;
102static struct dentry *min_free_entries_dent __read_mostly;
103static struct dentry *filter_dent __read_mostly;
104
105/* per-driver filter related state */
106
107#define NAME_MAX_LEN 64
108
109static char current_driver_name[NAME_MAX_LEN] __read_mostly;
110static struct device_driver *current_driver __read_mostly;
111
112static DEFINE_RWLOCK(driver_name_lock);
113
114static const char *type2name[4] = { "single", "page",
115                    "scather-gather", "coherent" };
116
117static const char *dir2name[4] = { "DMA_BIDIRECTIONAL", "DMA_TO_DEVICE",
118                   "DMA_FROM_DEVICE", "DMA_NONE" };
119
120/* little merge helper - remove it after the merge window */
121#ifndef BUS_NOTIFY_UNBOUND_DRIVER
122#define BUS_NOTIFY_UNBOUND_DRIVER 0x0005
123#endif
124
125/*
126 * The access to some variables in this macro is racy. We can't use atomic_t
127 * here because all these variables are exported to debugfs. Some of them even
128 * writeable. This is also the reason why a lock won't help much. But anyway,
129 * the races are no big deal. Here is why:
130 *
131 * error_count: the addition is racy, but the worst thing that can happen is
132 * that we don't count some errors
133 * show_num_errors: the subtraction is racy. Also no big deal because in
134 * worst case this will result in one warning more in the
135 * system log than the user configured. This variable is
136 * writeable via debugfs.
137 */
138static inline void dump_entry_trace(struct dma_debug_entry *entry)
139{
140#ifdef CONFIG_STACKTRACE
141    if (entry) {
142        pr_warning("Mapped at:\n");
143        print_stack_trace(&entry->stacktrace, 0);
144    }
145#endif
146}
147
148static bool driver_filter(struct device *dev)
149{
150    struct device_driver *drv;
151    unsigned long flags;
152    bool ret;
153
154    /* driver filter off */
155    if (likely(!current_driver_name[0]))
156        return true;
157
158    /* driver filter on and initialized */
159    if (current_driver && dev && dev->driver == current_driver)
160        return true;
161
162    /* driver filter on, but we can't filter on a NULL device... */
163    if (!dev)
164        return false;
165
166    if (current_driver || !current_driver_name[0])
167        return false;
168
169    /* driver filter on but not yet initialized */
170    drv = get_driver(dev->driver);
171    if (!drv)
172        return false;
173
174    /* lock to protect against change of current_driver_name */
175    read_lock_irqsave(&driver_name_lock, flags);
176
177    ret = false;
178    if (drv->name &&
179        strncmp(current_driver_name, drv->name, NAME_MAX_LEN - 1) == 0) {
180        current_driver = drv;
181        ret = true;
182    }
183
184    read_unlock_irqrestore(&driver_name_lock, flags);
185    put_driver(drv);
186
187    return ret;
188}
189
190#define err_printk(dev, entry, format, arg...) do { \
191        error_count += 1; \
192        if (driver_filter(dev) && \
193            (show_all_errors || show_num_errors > 0)) { \
194            WARN(1, "%s %s: " format, \
195                 dev ? dev_driver_string(dev) : "NULL", \
196                 dev ? dev_name(dev) : "NULL", ## arg); \
197            dump_entry_trace(entry); \
198        } \
199        if (!show_all_errors && show_num_errors > 0) \
200            show_num_errors -= 1; \
201    } while (0);
202
203/*
204 * Hash related functions
205 *
206 * Every DMA-API request is saved into a struct dma_debug_entry. To
207 * have quick access to these structs they are stored into a hash.
208 */
209static int hash_fn(struct dma_debug_entry *entry)
210{
211    /*
212     * Hash function is based on the dma address.
213     * We use bits 20-27 here as the index into the hash
214     */
215    return (entry->dev_addr >> HASH_FN_SHIFT) & HASH_FN_MASK;
216}
217
218/*
219 * Request exclusive access to a hash bucket for a given dma_debug_entry.
220 */
221static struct hash_bucket *get_hash_bucket(struct dma_debug_entry *entry,
222                       unsigned long *flags)
223{
224    int idx = hash_fn(entry);
225    unsigned long __flags;
226
227    spin_lock_irqsave(&dma_entry_hash[idx].lock, __flags);
228    *flags = __flags;
229    return &dma_entry_hash[idx];
230}
231
232/*
233 * Give up exclusive access to the hash bucket
234 */
235static void put_hash_bucket(struct hash_bucket *bucket,
236                unsigned long *flags)
237{
238    unsigned long __flags = *flags;
239
240    spin_unlock_irqrestore(&bucket->lock, __flags);
241}
242
243/*
244 * Search a given entry in the hash bucket list
245 */
246static struct dma_debug_entry *hash_bucket_find(struct hash_bucket *bucket,
247                        struct dma_debug_entry *ref)
248{
249    struct dma_debug_entry *entry, *ret = NULL;
250    int matches = 0, match_lvl, last_lvl = 0;
251
252    list_for_each_entry(entry, &bucket->list, list) {
253        if ((entry->dev_addr != ref->dev_addr) ||
254            (entry->dev != ref->dev))
255            continue;
256
257        /*
258         * Some drivers map the same physical address multiple
259         * times. Without a hardware IOMMU this results in the
260         * same device addresses being put into the dma-debug
261         * hash multiple times too. This can result in false
262         * positives being reported. Therefore we implement a
263         * best-fit algorithm here which returns the entry from
264         * the hash which fits best to the reference value
265         * instead of the first-fit.
266         */
267        matches += 1;
268        match_lvl = 0;
269        entry->size == ref->size ? ++match_lvl : 0;
270        entry->type == ref->type ? ++match_lvl : 0;
271        entry->direction == ref->direction ? ++match_lvl : 0;
272        entry->sg_call_ents == ref->sg_call_ents ? ++match_lvl : 0;
273
274        if (match_lvl == 4) {
275            /* perfect-fit - return the result */
276            return entry;
277        } else if (match_lvl > last_lvl) {
278            /*
279             * We found an entry that fits better then the
280             * previous one
281             */
282            last_lvl = match_lvl;
283            ret = entry;
284        }
285    }
286
287    /*
288     * If we have multiple matches but no perfect-fit, just return
289     * NULL.
290     */
291    ret = (matches == 1) ? ret : NULL;
292
293    return ret;
294}
295
296/*
297 * Add an entry to a hash bucket
298 */
299static void hash_bucket_add(struct hash_bucket *bucket,
300                struct dma_debug_entry *entry)
301{
302    list_add_tail(&entry->list, &bucket->list);
303}
304
305/*
306 * Remove entry from a hash bucket list
307 */
308static void hash_bucket_del(struct dma_debug_entry *entry)
309{
310    list_del(&entry->list);
311}
312
313/*
314 * Dump mapping entries for debugging purposes
315 */
316void debug_dma_dump_mappings(struct device *dev)
317{
318    int idx;
319
320    for (idx = 0; idx < HASH_SIZE; idx++) {
321        struct hash_bucket *bucket = &dma_entry_hash[idx];
322        struct dma_debug_entry *entry;
323        unsigned long flags;
324
325        spin_lock_irqsave(&bucket->lock, flags);
326
327        list_for_each_entry(entry, &bucket->list, list) {
328            if (!dev || dev == entry->dev) {
329                dev_info(entry->dev,
330                     "%s idx %d P=%Lx D=%Lx L=%Lx %s\n",
331                     type2name[entry->type], idx,
332                     (unsigned long long)entry->paddr,
333                     entry->dev_addr, entry->size,
334                     dir2name[entry->direction]);
335            }
336        }
337
338        spin_unlock_irqrestore(&bucket->lock, flags);
339    }
340}
341EXPORT_SYMBOL(debug_dma_dump_mappings);
342
343/*
344 * Wrapper function for adding an entry to the hash.
345 * This function takes care of locking itself.
346 */
347static void add_dma_entry(struct dma_debug_entry *entry)
348{
349    struct hash_bucket *bucket;
350    unsigned long flags;
351
352    bucket = get_hash_bucket(entry, &flags);
353    hash_bucket_add(bucket, entry);
354    put_hash_bucket(bucket, &flags);
355}
356
357static struct dma_debug_entry *__dma_entry_alloc(void)
358{
359    struct dma_debug_entry *entry;
360
361    entry = list_entry(free_entries.next, struct dma_debug_entry, list);
362    list_del(&entry->list);
363    memset(entry, 0, sizeof(*entry));
364
365    num_free_entries -= 1;
366    if (num_free_entries < min_free_entries)
367        min_free_entries = num_free_entries;
368
369    return entry;
370}
371
372/* struct dma_entry allocator
373 *
374 * The next two functions implement the allocator for
375 * struct dma_debug_entries.
376 */
377static struct dma_debug_entry *dma_entry_alloc(void)
378{
379    struct dma_debug_entry *entry = NULL;
380    unsigned long flags;
381
382    spin_lock_irqsave(&free_entries_lock, flags);
383
384    if (list_empty(&free_entries)) {
385        pr_err("DMA-API: debugging out of memory - disabling\n");
386        global_disable = true;
387        goto out;
388    }
389
390    entry = __dma_entry_alloc();
391
392#ifdef CONFIG_STACKTRACE
393    entry->stacktrace.max_entries = DMA_DEBUG_STACKTRACE_ENTRIES;
394    entry->stacktrace.entries = entry->st_entries;
395    entry->stacktrace.skip = 2;
396    save_stack_trace(&entry->stacktrace);
397#endif
398
399out:
400    spin_unlock_irqrestore(&free_entries_lock, flags);
401
402    return entry;
403}
404
405static void dma_entry_free(struct dma_debug_entry *entry)
406{
407    unsigned long flags;
408
409    /*
410     * add to beginning of the list - this way the entries are
411     * more likely cache hot when they are reallocated.
412     */
413    spin_lock_irqsave(&free_entries_lock, flags);
414    list_add(&entry->list, &free_entries);
415    num_free_entries += 1;
416    spin_unlock_irqrestore(&free_entries_lock, flags);
417}
418
419int dma_debug_resize_entries(u32 num_entries)
420{
421    int i, delta, ret = 0;
422    unsigned long flags;
423    struct dma_debug_entry *entry;
424    LIST_HEAD(tmp);
425
426    spin_lock_irqsave(&free_entries_lock, flags);
427
428    if (nr_total_entries < num_entries) {
429        delta = num_entries - nr_total_entries;
430
431        spin_unlock_irqrestore(&free_entries_lock, flags);
432
433        for (i = 0; i < delta; i++) {
434            entry = kzalloc(sizeof(*entry), GFP_KERNEL);
435            if (!entry)
436                break;
437
438            list_add_tail(&entry->list, &tmp);
439        }
440
441        spin_lock_irqsave(&free_entries_lock, flags);
442
443        list_splice(&tmp, &free_entries);
444        nr_total_entries += i;
445        num_free_entries += i;
446    } else {
447        delta = nr_total_entries - num_entries;
448
449        for (i = 0; i < delta && !list_empty(&free_entries); i++) {
450            entry = __dma_entry_alloc();
451            kfree(entry);
452        }
453
454        nr_total_entries -= i;
455    }
456
457    if (nr_total_entries != num_entries)
458        ret = 1;
459
460    spin_unlock_irqrestore(&free_entries_lock, flags);
461
462    return ret;
463}
464EXPORT_SYMBOL(dma_debug_resize_entries);
465
466/*
467 * DMA-API debugging init code
468 *
469 * The init code does two things:
470 * 1. Initialize core data structures
471 * 2. Preallocate a given number of dma_debug_entry structs
472 */
473
474static int prealloc_memory(u32 num_entries)
475{
476    struct dma_debug_entry *entry, *next_entry;
477    int i;
478
479    for (i = 0; i < num_entries; ++i) {
480        entry = kzalloc(sizeof(*entry), GFP_KERNEL);
481        if (!entry)
482            goto out_err;
483
484        list_add_tail(&entry->list, &free_entries);
485    }
486
487    num_free_entries = num_entries;
488    min_free_entries = num_entries;
489
490    pr_info("DMA-API: preallocated %d debug entries\n", num_entries);
491
492    return 0;
493
494out_err:
495
496    list_for_each_entry_safe(entry, next_entry, &free_entries, list) {
497        list_del(&entry->list);
498        kfree(entry);
499    }
500
501    return -ENOMEM;
502}
503
504static ssize_t filter_read(struct file *file, char __user *user_buf,
505               size_t count, loff_t *ppos)
506{
507    char buf[NAME_MAX_LEN + 1];
508    unsigned long flags;
509    int len;
510
511    if (!current_driver_name[0])
512        return 0;
513
514    /*
515     * We can't copy to userspace directly because current_driver_name can
516     * only be read under the driver_name_lock with irqs disabled. So
517     * create a temporary copy first.
518     */
519    read_lock_irqsave(&driver_name_lock, flags);
520    len = scnprintf(buf, NAME_MAX_LEN + 1, "%s\n", current_driver_name);
521    read_unlock_irqrestore(&driver_name_lock, flags);
522
523    return simple_read_from_buffer(user_buf, count, ppos, buf, len);
524}
525
526static ssize_t filter_write(struct file *file, const char __user *userbuf,
527                size_t count, loff_t *ppos)
528{
529    char buf[NAME_MAX_LEN];
530    unsigned long flags;
531    size_t len;
532    int i;
533
534    /*
535     * We can't copy from userspace directly. Access to
536     * current_driver_name is protected with a write_lock with irqs
537     * disabled. Since copy_from_user can fault and may sleep we
538     * need to copy to temporary buffer first
539     */
540    len = min(count, (size_t)(NAME_MAX_LEN - 1));
541    if (copy_from_user(buf, userbuf, len))
542        return -EFAULT;
543
544    buf[len] = 0;
545
546    write_lock_irqsave(&driver_name_lock, flags);
547
548    /*
549     * Now handle the string we got from userspace very carefully.
550     * The rules are:
551     * - only use the first token we got
552     * - token delimiter is everything looking like a space
553     * character (' ', '\n', '\t' ...)
554     *
555     */
556    if (!isalnum(buf[0])) {
557        /*
558         * If the first character userspace gave us is not
559         * alphanumerical then assume the filter should be
560         * switched off.
561         */
562        if (current_driver_name[0])
563            pr_info("DMA-API: switching off dma-debug driver filter\n");
564        current_driver_name[0] = 0;
565        current_driver = NULL;
566        goto out_unlock;
567    }
568
569    /*
570     * Now parse out the first token and use it as the name for the
571     * driver to filter for.
572     */
573    for (i = 0; i < NAME_MAX_LEN - 1; ++i) {
574        current_driver_name[i] = buf[i];
575        if (isspace(buf[i]) || buf[i] == ' ' || buf[i] == 0)
576            break;
577    }
578    current_driver_name[i] = 0;
579    current_driver = NULL;
580
581    pr_info("DMA-API: enable driver filter for driver [%s]\n",
582        current_driver_name);
583
584out_unlock:
585    write_unlock_irqrestore(&driver_name_lock, flags);
586
587    return count;
588}
589
590static const struct file_operations filter_fops = {
591    .read = filter_read,
592    .write = filter_write,
593};
594
595static int dma_debug_fs_init(void)
596{
597    dma_debug_dent = debugfs_create_dir("dma-api", NULL);
598    if (!dma_debug_dent) {
599        pr_err("DMA-API: can not create debugfs directory\n");
600        return -ENOMEM;
601    }
602
603    global_disable_dent = debugfs_create_bool("disabled", 0444,
604            dma_debug_dent,
605            (u32 *)&global_disable);
606    if (!global_disable_dent)
607        goto out_err;
608
609    error_count_dent = debugfs_create_u32("error_count", 0444,
610            dma_debug_dent, &error_count);
611    if (!error_count_dent)
612        goto out_err;
613
614    show_all_errors_dent = debugfs_create_u32("all_errors", 0644,
615            dma_debug_dent,
616            &show_all_errors);
617    if (!show_all_errors_dent)
618        goto out_err;
619
620    show_num_errors_dent = debugfs_create_u32("num_errors", 0644,
621            dma_debug_dent,
622            &show_num_errors);
623    if (!show_num_errors_dent)
624        goto out_err;
625
626    num_free_entries_dent = debugfs_create_u32("num_free_entries", 0444,
627            dma_debug_dent,
628            &num_free_entries);
629    if (!num_free_entries_dent)
630        goto out_err;
631
632    min_free_entries_dent = debugfs_create_u32("min_free_entries", 0444,
633            dma_debug_dent,
634            &min_free_entries);
635    if (!min_free_entries_dent)
636        goto out_err;
637
638    filter_dent = debugfs_create_file("driver_filter", 0644,
639                      dma_debug_dent, NULL, &filter_fops);
640    if (!filter_dent)
641        goto out_err;
642
643    return 0;
644
645out_err:
646    debugfs_remove_recursive(dma_debug_dent);
647
648    return -ENOMEM;
649}
650
651static int device_dma_allocations(struct device *dev)
652{
653    struct dma_debug_entry *entry;
654    unsigned long flags;
655    int count = 0, i;
656
657    local_irq_save(flags);
658
659    for (i = 0; i < HASH_SIZE; ++i) {
660        spin_lock(&dma_entry_hash[i].lock);
661        list_for_each_entry(entry, &dma_entry_hash[i].list, list) {
662            if (entry->dev == dev)
663                count += 1;
664        }
665        spin_unlock(&dma_entry_hash[i].lock);
666    }
667
668    local_irq_restore(flags);
669
670    return count;
671}
672
673static int dma_debug_device_change(struct notifier_block *nb, unsigned long action, void *data)
674{
675    struct device *dev = data;
676    int count;
677
678    if (global_disable)
679        return 0;
680
681    switch (action) {
682    case BUS_NOTIFY_UNBOUND_DRIVER:
683        count = device_dma_allocations(dev);
684        if (count == 0)
685            break;
686        err_printk(dev, NULL, "DMA-API: device driver has pending "
687                "DMA allocations while released from device "
688                "[count=%d]\n", count);
689        break;
690    default:
691        break;
692    }
693
694    return 0;
695}
696
697void dma_debug_add_bus(struct bus_type *bus)
698{
699    struct notifier_block *nb;
700
701    if (global_disable)
702        return;
703
704    nb = kzalloc(sizeof(struct notifier_block), GFP_KERNEL);
705    if (nb == NULL) {
706        pr_err("dma_debug_add_bus: out of memory\n");
707        return;
708    }
709
710    nb->notifier_call = dma_debug_device_change;
711
712    bus_register_notifier(bus, nb);
713}
714
715/*
716 * Let the architectures decide how many entries should be preallocated.
717 */
718void dma_debug_init(u32 num_entries)
719{
720    int i;
721
722    if (global_disable)
723        return;
724
725    for (i = 0; i < HASH_SIZE; ++i) {
726        INIT_LIST_HEAD(&dma_entry_hash[i].list);
727        spin_lock_init(&dma_entry_hash[i].lock);
728    }
729
730    if (dma_debug_fs_init() != 0) {
731        pr_err("DMA-API: error creating debugfs entries - disabling\n");
732        global_disable = true;
733
734        return;
735    }
736
737    if (req_entries)
738        num_entries = req_entries;
739
740    if (prealloc_memory(num_entries) != 0) {
741        pr_err("DMA-API: debugging out of memory error - disabled\n");
742        global_disable = true;
743
744        return;
745    }
746
747    nr_total_entries = num_free_entries;
748
749    pr_info("DMA-API: debugging enabled by kernel config\n");
750}
751
752static __init int dma_debug_cmdline(char *str)
753{
754    if (!str)
755        return -EINVAL;
756
757    if (strncmp(str, "off", 3) == 0) {
758        pr_info("DMA-API: debugging disabled on kernel command line\n");
759        global_disable = true;
760    }
761
762    return 0;
763}
764
765static __init int dma_debug_entries_cmdline(char *str)
766{
767    int res;
768
769    if (!str)
770        return -EINVAL;
771
772    res = get_option(&str, &req_entries);
773
774    if (!res)
775        req_entries = 0;
776
777    return 0;
778}
779
780__setup("dma_debug=", dma_debug_cmdline);
781__setup("dma_debug_entries=", dma_debug_entries_cmdline);
782
783static void check_unmap(struct dma_debug_entry *ref)
784{
785    struct dma_debug_entry *entry;
786    struct hash_bucket *bucket;
787    unsigned long flags;
788
789    if (dma_mapping_error(ref->dev, ref->dev_addr)) {
790        err_printk(ref->dev, NULL, "DMA-API: device driver tries "
791               "to free an invalid DMA memory address\n");
792        return;
793    }
794
795    bucket = get_hash_bucket(ref, &flags);
796    entry = hash_bucket_find(bucket, ref);
797
798    if (!entry) {
799        err_printk(ref->dev, NULL, "DMA-API: device driver tries "
800               "to free DMA memory it has not allocated "
801               "[device address=0x%016llx] [size=%llu bytes]\n",
802               ref->dev_addr, ref->size);
803        goto out;
804    }
805
806    if (ref->size != entry->size) {
807        err_printk(ref->dev, entry, "DMA-API: device driver frees "
808               "DMA memory with different size "
809               "[device address=0x%016llx] [map size=%llu bytes] "
810               "[unmap size=%llu bytes]\n",
811               ref->dev_addr, entry->size, ref->size);
812    }
813
814    if (ref->type != entry->type) {
815        err_printk(ref->dev, entry, "DMA-API: device driver frees "
816               "DMA memory with wrong function "
817               "[device address=0x%016llx] [size=%llu bytes] "
818               "[mapped as %s] [unmapped as %s]\n",
819               ref->dev_addr, ref->size,
820               type2name[entry->type], type2name[ref->type]);
821    } else if ((entry->type == dma_debug_coherent) &&
822           (ref->paddr != entry->paddr)) {
823        err_printk(ref->dev, entry, "DMA-API: device driver frees "
824               "DMA memory with different CPU address "
825               "[device address=0x%016llx] [size=%llu bytes] "
826               "[cpu alloc address=0x%016llx] "
827               "[cpu free address=0x%016llx]",
828               ref->dev_addr, ref->size,
829               (unsigned long long)entry->paddr,
830               (unsigned long long)ref->paddr);
831    }
832
833    if (ref->sg_call_ents && ref->type == dma_debug_sg &&
834        ref->sg_call_ents != entry->sg_call_ents) {
835        err_printk(ref->dev, entry, "DMA-API: device driver frees "
836               "DMA sg list with different entry count "
837               "[map count=%d] [unmap count=%d]\n",
838               entry->sg_call_ents, ref->sg_call_ents);
839    }
840
841    /*
842     * This may be no bug in reality - but most implementations of the
843     * DMA API don't handle this properly, so check for it here
844     */
845    if (ref->direction != entry->direction) {
846        err_printk(ref->dev, entry, "DMA-API: device driver frees "
847               "DMA memory with different direction "
848               "[device address=0x%016llx] [size=%llu bytes] "
849               "[mapped with %s] [unmapped with %s]\n",
850               ref->dev_addr, ref->size,
851               dir2name[entry->direction],
852               dir2name[ref->direction]);
853    }
854
855    hash_bucket_del(entry);
856    dma_entry_free(entry);
857
858out:
859    put_hash_bucket(bucket, &flags);
860}
861
862static void check_for_stack(struct device *dev, void *addr)
863{
864    if (object_is_on_stack(addr))
865        err_printk(dev, NULL, "DMA-API: device driver maps memory from"
866                "stack [addr=%p]\n", addr);
867}
868
869static inline bool overlap(void *addr, unsigned long len, void *start, void *end)
870{
871    unsigned long a1 = (unsigned long)addr;
872    unsigned long b1 = a1 + len;
873    unsigned long a2 = (unsigned long)start;
874    unsigned long b2 = (unsigned long)end;
875
876    return !(b1 <= a2 || a1 >= b2);
877}
878
879static void check_for_illegal_area(struct device *dev, void *addr, unsigned long len)
880{
881    if (overlap(addr, len, _text, _etext) ||
882        overlap(addr, len, __start_rodata, __end_rodata))
883        err_printk(dev, NULL, "DMA-API: device driver maps memory from kernel text or rodata [addr=%p] [len=%lu]\n", addr, len);
884}
885
886static void check_sync(struct device *dev,
887               struct dma_debug_entry *ref,
888               bool to_cpu)
889{
890    struct dma_debug_entry *entry;
891    struct hash_bucket *bucket;
892    unsigned long flags;
893
894    bucket = get_hash_bucket(ref, &flags);
895
896    entry = hash_bucket_find(bucket, ref);
897
898    if (!entry) {
899        err_printk(dev, NULL, "DMA-API: device driver tries "
900                "to sync DMA memory it has not allocated "
901                "[device address=0x%016llx] [size=%llu bytes]\n",
902                (unsigned long long)ref->dev_addr, ref->size);
903        goto out;
904    }
905
906    if (ref->size > entry->size) {
907        err_printk(dev, entry, "DMA-API: device driver syncs"
908                " DMA memory outside allocated range "
909                "[device address=0x%016llx] "
910                "[allocation size=%llu bytes] "
911                "[sync offset+size=%llu]\n",
912                entry->dev_addr, entry->size,
913                ref->size);
914    }
915
916    if (entry->direction == DMA_BIDIRECTIONAL)
917        goto out;
918
919    if (ref->direction != entry->direction) {
920        err_printk(dev, entry, "DMA-API: device driver syncs "
921                "DMA memory with different direction "
922                "[device address=0x%016llx] [size=%llu bytes] "
923                "[mapped with %s] [synced with %s]\n",
924                (unsigned long long)ref->dev_addr, entry->size,
925                dir2name[entry->direction],
926                dir2name[ref->direction]);
927    }
928
929    if (to_cpu && !(entry->direction == DMA_FROM_DEVICE) &&
930              !(ref->direction == DMA_TO_DEVICE))
931        err_printk(dev, entry, "DMA-API: device driver syncs "
932                "device read-only DMA memory for cpu "
933                "[device address=0x%016llx] [size=%llu bytes] "
934                "[mapped with %s] [synced with %s]\n",
935                (unsigned long long)ref->dev_addr, entry->size,
936                dir2name[entry->direction],
937                dir2name[ref->direction]);
938
939    if (!to_cpu && !(entry->direction == DMA_TO_DEVICE) &&
940               !(ref->direction == DMA_FROM_DEVICE))
941        err_printk(dev, entry, "DMA-API: device driver syncs "
942                "device write-only DMA memory to device "
943                "[device address=0x%016llx] [size=%llu bytes] "
944                "[mapped with %s] [synced with %s]\n",
945                (unsigned long long)ref->dev_addr, entry->size,
946                dir2name[entry->direction],
947                dir2name[ref->direction]);
948
949out:
950    put_hash_bucket(bucket, &flags);
951}
952
953void debug_dma_map_page(struct device *dev, struct page *page, size_t offset,
954            size_t size, int direction, dma_addr_t dma_addr,
955            bool map_single)
956{
957    struct dma_debug_entry *entry;
958
959    if (unlikely(global_disable))
960        return;
961
962    if (unlikely(dma_mapping_error(dev, dma_addr)))
963        return;
964
965    entry = dma_entry_alloc();
966    if (!entry)
967        return;
968
969    entry->dev = dev;
970    entry->type = dma_debug_page;
971    entry->paddr = page_to_phys(page) + offset;
972    entry->dev_addr = dma_addr;
973    entry->size = size;
974    entry->direction = direction;
975
976    if (map_single)
977        entry->type = dma_debug_single;
978
979    if (!PageHighMem(page)) {
980        void *addr = page_address(page) + offset;
981
982        check_for_stack(dev, addr);
983        check_for_illegal_area(dev, addr, size);
984    }
985
986    add_dma_entry(entry);
987}
988EXPORT_SYMBOL(debug_dma_map_page);
989
990void debug_dma_unmap_page(struct device *dev, dma_addr_t addr,
991              size_t size, int direction, bool map_single)
992{
993    struct dma_debug_entry ref = {
994        .type = dma_debug_page,
995        .dev = dev,
996        .dev_addr = addr,
997        .size = size,
998        .direction = direction,
999    };
1000
1001    if (unlikely(global_disable))
1002        return;
1003
1004    if (map_single)
1005        ref.type = dma_debug_single;
1006
1007    check_unmap(&ref);
1008}
1009EXPORT_SYMBOL(debug_dma_unmap_page);
1010
1011void debug_dma_map_sg(struct device *dev, struct scatterlist *sg,
1012              int nents, int mapped_ents, int direction)
1013{
1014    struct dma_debug_entry *entry;
1015    struct scatterlist *s;
1016    int i;
1017
1018    if (unlikely(global_disable))
1019        return;
1020
1021    for_each_sg(sg, s, mapped_ents, i) {
1022        entry = dma_entry_alloc();
1023        if (!entry)
1024            return;
1025
1026        entry->type = dma_debug_sg;
1027        entry->dev = dev;
1028        entry->paddr = sg_phys(s);
1029        entry->size = sg_dma_len(s);
1030        entry->dev_addr = sg_dma_address(s);
1031        entry->direction = direction;
1032        entry->sg_call_ents = nents;
1033        entry->sg_mapped_ents = mapped_ents;
1034
1035        if (!PageHighMem(sg_page(s))) {
1036            check_for_stack(dev, sg_virt(s));
1037            check_for_illegal_area(dev, sg_virt(s), sg_dma_len(s));
1038        }
1039
1040        add_dma_entry(entry);
1041    }
1042}
1043EXPORT_SYMBOL(debug_dma_map_sg);
1044
1045static int get_nr_mapped_entries(struct device *dev,
1046                 struct dma_debug_entry *ref)
1047{
1048    struct dma_debug_entry *entry;
1049    struct hash_bucket *bucket;
1050    unsigned long flags;
1051    int mapped_ents;
1052
1053    bucket = get_hash_bucket(ref, &flags);
1054    entry = hash_bucket_find(bucket, ref);
1055    mapped_ents = 0;
1056
1057    if (entry)
1058        mapped_ents = entry->sg_mapped_ents;
1059    put_hash_bucket(bucket, &flags);
1060
1061    return mapped_ents;
1062}
1063
1064void debug_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
1065            int nelems, int dir)
1066{
1067    struct scatterlist *s;
1068    int mapped_ents = 0, i;
1069
1070    if (unlikely(global_disable))
1071        return;
1072
1073    for_each_sg(sglist, s, nelems, i) {
1074
1075        struct dma_debug_entry ref = {
1076            .type = dma_debug_sg,
1077            .dev = dev,
1078            .paddr = sg_phys(s),
1079            .dev_addr = sg_dma_address(s),
1080            .size = sg_dma_len(s),
1081            .direction = dir,
1082            .sg_call_ents = nelems,
1083        };
1084
1085        if (mapped_ents && i >= mapped_ents)
1086            break;
1087
1088        if (!i)
1089            mapped_ents = get_nr_mapped_entries(dev, &ref);
1090
1091        check_unmap(&ref);
1092    }
1093}
1094EXPORT_SYMBOL(debug_dma_unmap_sg);
1095
1096void debug_dma_alloc_coherent(struct device *dev, size_t size,
1097                  dma_addr_t dma_addr, void *virt)
1098{
1099    struct dma_debug_entry *entry;
1100
1101    if (unlikely(global_disable))
1102        return;
1103
1104    if (unlikely(virt == NULL))
1105        return;
1106
1107    entry = dma_entry_alloc();
1108    if (!entry)
1109        return;
1110
1111    entry->type = dma_debug_coherent;
1112    entry->dev = dev;
1113    entry->paddr = virt_to_phys(virt);
1114    entry->size = size;
1115    entry->dev_addr = dma_addr;
1116    entry->direction = DMA_BIDIRECTIONAL;
1117
1118    add_dma_entry(entry);
1119}
1120EXPORT_SYMBOL(debug_dma_alloc_coherent);
1121
1122void debug_dma_free_coherent(struct device *dev, size_t size,
1123             void *virt, dma_addr_t addr)
1124{
1125    struct dma_debug_entry ref = {
1126        .type = dma_debug_coherent,
1127        .dev = dev,
1128        .paddr = virt_to_phys(virt),
1129        .dev_addr = addr,
1130        .size = size,
1131        .direction = DMA_BIDIRECTIONAL,
1132    };
1133
1134    if (unlikely(global_disable))
1135        return;
1136
1137    check_unmap(&ref);
1138}
1139EXPORT_SYMBOL(debug_dma_free_coherent);
1140
1141void debug_dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_handle,
1142                   size_t size, int direction)
1143{
1144    struct dma_debug_entry ref;
1145
1146    if (unlikely(global_disable))
1147        return;
1148
1149    ref.type = dma_debug_single;
1150    ref.dev = dev;
1151    ref.dev_addr = dma_handle;
1152    ref.size = size;
1153    ref.direction = direction;
1154    ref.sg_call_ents = 0;
1155
1156    check_sync(dev, &ref, true);
1157}
1158EXPORT_SYMBOL(debug_dma_sync_single_for_cpu);
1159
1160void debug_dma_sync_single_for_device(struct device *dev,
1161                      dma_addr_t dma_handle, size_t size,
1162                      int direction)
1163{
1164    struct dma_debug_entry ref;
1165
1166    if (unlikely(global_disable))
1167        return;
1168
1169    ref.type = dma_debug_single;
1170    ref.dev = dev;
1171    ref.dev_addr = dma_handle;
1172    ref.size = size;
1173    ref.direction = direction;
1174    ref.sg_call_ents = 0;
1175
1176    check_sync(dev, &ref, false);
1177}
1178EXPORT_SYMBOL(debug_dma_sync_single_for_device);
1179
1180void debug_dma_sync_single_range_for_cpu(struct device *dev,
1181                     dma_addr_t dma_handle,
1182                     unsigned long offset, size_t size,
1183                     int direction)
1184{
1185    struct dma_debug_entry ref;
1186
1187    if (unlikely(global_disable))
1188        return;
1189
1190    ref.type = dma_debug_single;
1191    ref.dev = dev;
1192    ref.dev_addr = dma_handle;
1193    ref.size = offset + size;
1194    ref.direction = direction;
1195    ref.sg_call_ents = 0;
1196
1197    check_sync(dev, &ref, true);
1198}
1199EXPORT_SYMBOL(debug_dma_sync_single_range_for_cpu);
1200
1201void debug_dma_sync_single_range_for_device(struct device *dev,
1202                        dma_addr_t dma_handle,
1203                        unsigned long offset,
1204                        size_t size, int direction)
1205{
1206    struct dma_debug_entry ref;
1207
1208    if (unlikely(global_disable))
1209        return;
1210
1211    ref.type = dma_debug_single;
1212    ref.dev = dev;
1213    ref.dev_addr = dma_handle;
1214    ref.size = offset + size;
1215    ref.direction = direction;
1216    ref.sg_call_ents = 0;
1217
1218    check_sync(dev, &ref, false);
1219}
1220EXPORT_SYMBOL(debug_dma_sync_single_range_for_device);
1221
1222void debug_dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
1223                   int nelems, int direction)
1224{
1225    struct scatterlist *s;
1226    int mapped_ents = 0, i;
1227
1228    if (unlikely(global_disable))
1229        return;
1230
1231    for_each_sg(sg, s, nelems, i) {
1232
1233        struct dma_debug_entry ref = {
1234            .type = dma_debug_sg,
1235            .dev = dev,
1236            .paddr = sg_phys(s),
1237            .dev_addr = sg_dma_address(s),
1238            .size = sg_dma_len(s),
1239            .direction = direction,
1240            .sg_call_ents = nelems,
1241        };
1242
1243        if (!i)
1244            mapped_ents = get_nr_mapped_entries(dev, &ref);
1245
1246        if (i >= mapped_ents)
1247            break;
1248
1249        check_sync(dev, &ref, true);
1250    }
1251}
1252EXPORT_SYMBOL(debug_dma_sync_sg_for_cpu);
1253
1254void debug_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
1255                  int nelems, int direction)
1256{
1257    struct scatterlist *s;
1258    int mapped_ents = 0, i;
1259
1260    if (unlikely(global_disable))
1261        return;
1262
1263    for_each_sg(sg, s, nelems, i) {
1264
1265        struct dma_debug_entry ref = {
1266            .type = dma_debug_sg,
1267            .dev = dev,
1268            .paddr = sg_phys(s),
1269            .dev_addr = sg_dma_address(s),
1270            .size = sg_dma_len(s),
1271            .direction = direction,
1272            .sg_call_ents = nelems,
1273        };
1274        if (!i)
1275            mapped_ents = get_nr_mapped_entries(dev, &ref);
1276
1277        if (i >= mapped_ents)
1278            break;
1279
1280        check_sync(dev, &ref, false);
1281    }
1282}
1283EXPORT_SYMBOL(debug_dma_sync_sg_for_device);
1284
1285static int __init dma_debug_driver_setup(char *str)
1286{
1287    int i;
1288
1289    for (i = 0; i < NAME_MAX_LEN - 1; ++i, ++str) {
1290        current_driver_name[i] = *str;
1291        if (*str == 0)
1292            break;
1293    }
1294
1295    if (current_driver_name[0])
1296        pr_info("DMA-API: enable driver filter for driver [%s]\n",
1297            current_driver_name);
1298
1299
1300    return 1;
1301}
1302__setup("dma_debug_driver=", dma_debug_driver_setup);
1303

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