Root/lib/dma-debug.c

Source at commit b386be689295730688885552666ea40b2e639b14 created 8 years 11 months ago.
By Maarten ter Huurne, Revert "MIPS: JZ4740: reset: Initialize hibernate wakeup counters."
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/export.h>
28#include <linux/device.h>
29#include <linux/types.h>
30#include <linux/sched.h>
31#include <linux/ctype.h>
32#include <linux/list.h>
33#include <linux/slab.h>
34
35#include <asm/sections.h>
36
37#define HASH_SIZE 1024ULL
38#define HASH_FN_SHIFT 13
39#define HASH_FN_MASK (HASH_SIZE - 1)
40
41enum {
42    dma_debug_single,
43    dma_debug_page,
44    dma_debug_sg,
45    dma_debug_coherent,
46};
47
48#define DMA_DEBUG_STACKTRACE_ENTRIES 5
49
50struct dma_debug_entry {
51    struct list_head list;
52    struct device *dev;
53    int type;
54    phys_addr_t paddr;
55    u64 dev_addr;
56    u64 size;
57    int direction;
58    int sg_call_ents;
59    int sg_mapped_ents;
60#ifdef CONFIG_STACKTRACE
61    struct stack_trace stacktrace;
62    unsigned long st_entries[DMA_DEBUG_STACKTRACE_ENTRIES];
63#endif
64};
65
66typedef bool (*match_fn)(struct dma_debug_entry *, struct dma_debug_entry *);
67
68struct hash_bucket {
69    struct list_head list;
70    spinlock_t lock;
71} ____cacheline_aligned_in_smp;
72
73/* Hash list to save the allocated dma addresses */
74static struct hash_bucket dma_entry_hash[HASH_SIZE];
75/* List of pre-allocated dma_debug_entry's */
76static LIST_HEAD(free_entries);
77/* Lock for the list above */
78static DEFINE_SPINLOCK(free_entries_lock);
79
80/* Global disable flag - will be set in case of an error */
81static bool global_disable __read_mostly;
82
83/* Global error count */
84static u32 error_count;
85
86/* Global error show enable*/
87static u32 show_all_errors __read_mostly;
88/* Number of errors to show */
89static u32 show_num_errors = 1;
90
91static u32 num_free_entries;
92static u32 min_free_entries;
93static u32 nr_total_entries;
94
95/* number of preallocated entries requested by kernel cmdline */
96static u32 req_entries;
97
98/* debugfs dentry's for the stuff above */
99static struct dentry *dma_debug_dent __read_mostly;
100static struct dentry *global_disable_dent __read_mostly;
101static struct dentry *error_count_dent __read_mostly;
102static struct dentry *show_all_errors_dent __read_mostly;
103static struct dentry *show_num_errors_dent __read_mostly;
104static struct dentry *num_free_entries_dent __read_mostly;
105static struct dentry *min_free_entries_dent __read_mostly;
106static struct dentry *filter_dent __read_mostly;
107
108/* per-driver filter related state */
109
110#define NAME_MAX_LEN 64
111
112static char current_driver_name[NAME_MAX_LEN] __read_mostly;
113static struct device_driver *current_driver __read_mostly;
114
115static DEFINE_RWLOCK(driver_name_lock);
116
117static const char *type2name[4] = { "single", "page",
118                    "scather-gather", "coherent" };
119
120static const char *dir2name[4] = { "DMA_BIDIRECTIONAL", "DMA_TO_DEVICE",
121                   "DMA_FROM_DEVICE", "DMA_NONE" };
122
123/* little merge helper - remove it after the merge window */
124#ifndef BUS_NOTIFY_UNBOUND_DRIVER
125#define BUS_NOTIFY_UNBOUND_DRIVER 0x0005
126#endif
127
128/*
129 * The access to some variables in this macro is racy. We can't use atomic_t
130 * here because all these variables are exported to debugfs. Some of them even
131 * writeable. This is also the reason why a lock won't help much. But anyway,
132 * the races are no big deal. Here is why:
133 *
134 * error_count: the addition is racy, but the worst thing that can happen is
135 * that we don't count some errors
136 * show_num_errors: the subtraction is racy. Also no big deal because in
137 * worst case this will result in one warning more in the
138 * system log than the user configured. This variable is
139 * writeable via debugfs.
140 */
141static inline void dump_entry_trace(struct dma_debug_entry *entry)
142{
143#ifdef CONFIG_STACKTRACE
144    if (entry) {
145        pr_warning("Mapped at:\n");
146        print_stack_trace(&entry->stacktrace, 0);
147    }
148#endif
149}
150
151static bool driver_filter(struct device *dev)
152{
153    struct device_driver *drv;
154    unsigned long flags;
155    bool ret;
156
157    /* driver filter off */
158    if (likely(!current_driver_name[0]))
159        return true;
160
161    /* driver filter on and initialized */
162    if (current_driver && dev && dev->driver == current_driver)
163        return true;
164
165    /* driver filter on, but we can't filter on a NULL device... */
166    if (!dev)
167        return false;
168
169    if (current_driver || !current_driver_name[0])
170        return false;
171
172    /* driver filter on but not yet initialized */
173    drv = get_driver(dev->driver);
174    if (!drv)
175        return false;
176
177    /* lock to protect against change of current_driver_name */
178    read_lock_irqsave(&driver_name_lock, flags);
179
180    ret = false;
181    if (drv->name &&
182        strncmp(current_driver_name, drv->name, NAME_MAX_LEN - 1) == 0) {
183        current_driver = drv;
184        ret = true;
185    }
186
187    read_unlock_irqrestore(&driver_name_lock, flags);
188    put_driver(drv);
189
190    return ret;
191}
192
193#define err_printk(dev, entry, format, arg...) do { \
194        error_count += 1; \
195        if (driver_filter(dev) && \
196            (show_all_errors || show_num_errors > 0)) { \
197            WARN(1, "%s %s: " format, \
198                 dev ? dev_driver_string(dev) : "NULL", \
199                 dev ? dev_name(dev) : "NULL", ## arg); \
200            dump_entry_trace(entry); \
201        } \
202        if (!show_all_errors && show_num_errors > 0) \
203            show_num_errors -= 1; \
204    } while (0);
205
206/*
207 * Hash related functions
208 *
209 * Every DMA-API request is saved into a struct dma_debug_entry. To
210 * have quick access to these structs they are stored into a hash.
211 */
212static int hash_fn(struct dma_debug_entry *entry)
213{
214    /*
215     * Hash function is based on the dma address.
216     * We use bits 20-27 here as the index into the hash
217     */
218    return (entry->dev_addr >> HASH_FN_SHIFT) & HASH_FN_MASK;
219}
220
221/*
222 * Request exclusive access to a hash bucket for a given dma_debug_entry.
223 */
224static struct hash_bucket *get_hash_bucket(struct dma_debug_entry *entry,
225                       unsigned long *flags)
226{
227    int idx = hash_fn(entry);
228    unsigned long __flags;
229
230    spin_lock_irqsave(&dma_entry_hash[idx].lock, __flags);
231    *flags = __flags;
232    return &dma_entry_hash[idx];
233}
234
235/*
236 * Give up exclusive access to the hash bucket
237 */
238static void put_hash_bucket(struct hash_bucket *bucket,
239                unsigned long *flags)
240{
241    unsigned long __flags = *flags;
242
243    spin_unlock_irqrestore(&bucket->lock, __flags);
244}
245
246static bool exact_match(struct dma_debug_entry *a, struct dma_debug_entry *b)
247{
248    return ((a->dev_addr == b->dev_addr) &&
249        (a->dev == b->dev)) ? true : false;
250}
251
252static bool containing_match(struct dma_debug_entry *a,
253                 struct dma_debug_entry *b)
254{
255    if (a->dev != b->dev)
256        return false;
257
258    if ((b->dev_addr <= a->dev_addr) &&
259        ((b->dev_addr + b->size) >= (a->dev_addr + a->size)))
260        return true;
261
262    return false;
263}
264
265/*
266 * Search a given entry in the hash bucket list
267 */
268static struct dma_debug_entry *__hash_bucket_find(struct hash_bucket *bucket,
269                          struct dma_debug_entry *ref,
270                          match_fn match)
271{
272    struct dma_debug_entry *entry, *ret = NULL;
273    int matches = 0, match_lvl, last_lvl = 0;
274
275    list_for_each_entry(entry, &bucket->list, list) {
276        if (!match(ref, entry))
277            continue;
278
279        /*
280         * Some drivers map the same physical address multiple
281         * times. Without a hardware IOMMU this results in the
282         * same device addresses being put into the dma-debug
283         * hash multiple times too. This can result in false
284         * positives being reported. Therefore we implement a
285         * best-fit algorithm here which returns the entry from
286         * the hash which fits best to the reference value
287         * instead of the first-fit.
288         */
289        matches += 1;
290        match_lvl = 0;
291        entry->size == ref->size ? ++match_lvl : 0;
292        entry->type == ref->type ? ++match_lvl : 0;
293        entry->direction == ref->direction ? ++match_lvl : 0;
294        entry->sg_call_ents == ref->sg_call_ents ? ++match_lvl : 0;
295
296        if (match_lvl == 4) {
297            /* perfect-fit - return the result */
298            return entry;
299        } else if (match_lvl > last_lvl) {
300            /*
301             * We found an entry that fits better then the
302             * previous one
303             */
304            last_lvl = match_lvl;
305            ret = entry;
306        }
307    }
308
309    /*
310     * If we have multiple matches but no perfect-fit, just return
311     * NULL.
312     */
313    ret = (matches == 1) ? ret : NULL;
314
315    return ret;
316}
317
318static struct dma_debug_entry *bucket_find_exact(struct hash_bucket *bucket,
319                         struct dma_debug_entry *ref)
320{
321    return __hash_bucket_find(bucket, ref, exact_match);
322}
323
324static struct dma_debug_entry *bucket_find_contain(struct hash_bucket **bucket,
325                           struct dma_debug_entry *ref,
326                           unsigned long *flags)
327{
328
329    unsigned int max_range = dma_get_max_seg_size(ref->dev);
330    struct dma_debug_entry *entry, index = *ref;
331    unsigned int range = 0;
332
333    while (range <= max_range) {
334        entry = __hash_bucket_find(*bucket, &index, containing_match);
335
336        if (entry)
337            return entry;
338
339        /*
340         * Nothing found, go back a hash bucket
341         */
342        put_hash_bucket(*bucket, flags);
343        range += (1 << HASH_FN_SHIFT);
344        index.dev_addr -= (1 << HASH_FN_SHIFT);
345        *bucket = get_hash_bucket(&index, flags);
346    }
347
348    return NULL;
349}
350
351/*
352 * Add an entry to a hash bucket
353 */
354static void hash_bucket_add(struct hash_bucket *bucket,
355                struct dma_debug_entry *entry)
356{
357    list_add_tail(&entry->list, &bucket->list);
358}
359
360/*
361 * Remove entry from a hash bucket list
362 */
363static void hash_bucket_del(struct dma_debug_entry *entry)
364{
365    list_del(&entry->list);
366}
367
368/*
369 * Dump mapping entries for debugging purposes
370 */
371void debug_dma_dump_mappings(struct device *dev)
372{
373    int idx;
374
375    for (idx = 0; idx < HASH_SIZE; idx++) {
376        struct hash_bucket *bucket = &dma_entry_hash[idx];
377        struct dma_debug_entry *entry;
378        unsigned long flags;
379
380        spin_lock_irqsave(&bucket->lock, flags);
381
382        list_for_each_entry(entry, &bucket->list, list) {
383            if (!dev || dev == entry->dev) {
384                dev_info(entry->dev,
385                     "%s idx %d P=%Lx D=%Lx L=%Lx %s\n",
386                     type2name[entry->type], idx,
387                     (unsigned long long)entry->paddr,
388                     entry->dev_addr, entry->size,
389                     dir2name[entry->direction]);
390            }
391        }
392
393        spin_unlock_irqrestore(&bucket->lock, flags);
394    }
395}
396EXPORT_SYMBOL(debug_dma_dump_mappings);
397
398/*
399 * Wrapper function for adding an entry to the hash.
400 * This function takes care of locking itself.
401 */
402static void add_dma_entry(struct dma_debug_entry *entry)
403{
404    struct hash_bucket *bucket;
405    unsigned long flags;
406
407    bucket = get_hash_bucket(entry, &flags);
408    hash_bucket_add(bucket, entry);
409    put_hash_bucket(bucket, &flags);
410}
411
412static struct dma_debug_entry *__dma_entry_alloc(void)
413{
414    struct dma_debug_entry *entry;
415
416    entry = list_entry(free_entries.next, struct dma_debug_entry, list);
417    list_del(&entry->list);
418    memset(entry, 0, sizeof(*entry));
419
420    num_free_entries -= 1;
421    if (num_free_entries < min_free_entries)
422        min_free_entries = num_free_entries;
423
424    return entry;
425}
426
427/* struct dma_entry allocator
428 *
429 * The next two functions implement the allocator for
430 * struct dma_debug_entries.
431 */
432static struct dma_debug_entry *dma_entry_alloc(void)
433{
434    struct dma_debug_entry *entry = NULL;
435    unsigned long flags;
436
437    spin_lock_irqsave(&free_entries_lock, flags);
438
439    if (list_empty(&free_entries)) {
440        pr_err("DMA-API: debugging out of memory - disabling\n");
441        global_disable = true;
442        goto out;
443    }
444
445    entry = __dma_entry_alloc();
446
447#ifdef CONFIG_STACKTRACE
448    entry->stacktrace.max_entries = DMA_DEBUG_STACKTRACE_ENTRIES;
449    entry->stacktrace.entries = entry->st_entries;
450    entry->stacktrace.skip = 2;
451    save_stack_trace(&entry->stacktrace);
452#endif
453
454out:
455    spin_unlock_irqrestore(&free_entries_lock, flags);
456
457    return entry;
458}
459
460static void dma_entry_free(struct dma_debug_entry *entry)
461{
462    unsigned long flags;
463
464    /*
465     * add to beginning of the list - this way the entries are
466     * more likely cache hot when they are reallocated.
467     */
468    spin_lock_irqsave(&free_entries_lock, flags);
469    list_add(&entry->list, &free_entries);
470    num_free_entries += 1;
471    spin_unlock_irqrestore(&free_entries_lock, flags);
472}
473
474int dma_debug_resize_entries(u32 num_entries)
475{
476    int i, delta, ret = 0;
477    unsigned long flags;
478    struct dma_debug_entry *entry;
479    LIST_HEAD(tmp);
480
481    spin_lock_irqsave(&free_entries_lock, flags);
482
483    if (nr_total_entries < num_entries) {
484        delta = num_entries - nr_total_entries;
485
486        spin_unlock_irqrestore(&free_entries_lock, flags);
487
488        for (i = 0; i < delta; i++) {
489            entry = kzalloc(sizeof(*entry), GFP_KERNEL);
490            if (!entry)
491                break;
492
493            list_add_tail(&entry->list, &tmp);
494        }
495
496        spin_lock_irqsave(&free_entries_lock, flags);
497
498        list_splice(&tmp, &free_entries);
499        nr_total_entries += i;
500        num_free_entries += i;
501    } else {
502        delta = nr_total_entries - num_entries;
503
504        for (i = 0; i < delta && !list_empty(&free_entries); i++) {
505            entry = __dma_entry_alloc();
506            kfree(entry);
507        }
508
509        nr_total_entries -= i;
510    }
511
512    if (nr_total_entries != num_entries)
513        ret = 1;
514
515    spin_unlock_irqrestore(&free_entries_lock, flags);
516
517    return ret;
518}
519EXPORT_SYMBOL(dma_debug_resize_entries);
520
521/*
522 * DMA-API debugging init code
523 *
524 * The init code does two things:
525 * 1. Initialize core data structures
526 * 2. Preallocate a given number of dma_debug_entry structs
527 */
528
529static int prealloc_memory(u32 num_entries)
530{
531    struct dma_debug_entry *entry, *next_entry;
532    int i;
533
534    for (i = 0; i < num_entries; ++i) {
535        entry = kzalloc(sizeof(*entry), GFP_KERNEL);
536        if (!entry)
537            goto out_err;
538
539        list_add_tail(&entry->list, &free_entries);
540    }
541
542    num_free_entries = num_entries;
543    min_free_entries = num_entries;
544
545    pr_info("DMA-API: preallocated %d debug entries\n", num_entries);
546
547    return 0;
548
549out_err:
550
551    list_for_each_entry_safe(entry, next_entry, &free_entries, list) {
552        list_del(&entry->list);
553        kfree(entry);
554    }
555
556    return -ENOMEM;
557}
558
559static ssize_t filter_read(struct file *file, char __user *user_buf,
560               size_t count, loff_t *ppos)
561{
562    char buf[NAME_MAX_LEN + 1];
563    unsigned long flags;
564    int len;
565
566    if (!current_driver_name[0])
567        return 0;
568
569    /*
570     * We can't copy to userspace directly because current_driver_name can
571     * only be read under the driver_name_lock with irqs disabled. So
572     * create a temporary copy first.
573     */
574    read_lock_irqsave(&driver_name_lock, flags);
575    len = scnprintf(buf, NAME_MAX_LEN + 1, "%s\n", current_driver_name);
576    read_unlock_irqrestore(&driver_name_lock, flags);
577
578    return simple_read_from_buffer(user_buf, count, ppos, buf, len);
579}
580
581static ssize_t filter_write(struct file *file, const char __user *userbuf,
582                size_t count, loff_t *ppos)
583{
584    char buf[NAME_MAX_LEN];
585    unsigned long flags;
586    size_t len;
587    int i;
588
589    /*
590     * We can't copy from userspace directly. Access to
591     * current_driver_name is protected with a write_lock with irqs
592     * disabled. Since copy_from_user can fault and may sleep we
593     * need to copy to temporary buffer first
594     */
595    len = min(count, (size_t)(NAME_MAX_LEN - 1));
596    if (copy_from_user(buf, userbuf, len))
597        return -EFAULT;
598
599    buf[len] = 0;
600
601    write_lock_irqsave(&driver_name_lock, flags);
602
603    /*
604     * Now handle the string we got from userspace very carefully.
605     * The rules are:
606     * - only use the first token we got
607     * - token delimiter is everything looking like a space
608     * character (' ', '\n', '\t' ...)
609     *
610     */
611    if (!isalnum(buf[0])) {
612        /*
613         * If the first character userspace gave us is not
614         * alphanumerical then assume the filter should be
615         * switched off.
616         */
617        if (current_driver_name[0])
618            pr_info("DMA-API: switching off dma-debug driver filter\n");
619        current_driver_name[0] = 0;
620        current_driver = NULL;
621        goto out_unlock;
622    }
623
624    /*
625     * Now parse out the first token and use it as the name for the
626     * driver to filter for.
627     */
628    for (i = 0; i < NAME_MAX_LEN - 1; ++i) {
629        current_driver_name[i] = buf[i];
630        if (isspace(buf[i]) || buf[i] == ' ' || buf[i] == 0)
631            break;
632    }
633    current_driver_name[i] = 0;
634    current_driver = NULL;
635
636    pr_info("DMA-API: enable driver filter for driver [%s]\n",
637        current_driver_name);
638
639out_unlock:
640    write_unlock_irqrestore(&driver_name_lock, flags);
641
642    return count;
643}
644
645static const struct file_operations filter_fops = {
646    .read = filter_read,
647    .write = filter_write,
648    .llseek = default_llseek,
649};
650
651static int dma_debug_fs_init(void)
652{
653    dma_debug_dent = debugfs_create_dir("dma-api", NULL);
654    if (!dma_debug_dent) {
655        pr_err("DMA-API: can not create debugfs directory\n");
656        return -ENOMEM;
657    }
658
659    global_disable_dent = debugfs_create_bool("disabled", 0444,
660            dma_debug_dent,
661            (u32 *)&global_disable);
662    if (!global_disable_dent)
663        goto out_err;
664
665    error_count_dent = debugfs_create_u32("error_count", 0444,
666            dma_debug_dent, &error_count);
667    if (!error_count_dent)
668        goto out_err;
669
670    show_all_errors_dent = debugfs_create_u32("all_errors", 0644,
671            dma_debug_dent,
672            &show_all_errors);
673    if (!show_all_errors_dent)
674        goto out_err;
675
676    show_num_errors_dent = debugfs_create_u32("num_errors", 0644,
677            dma_debug_dent,
678            &show_num_errors);
679    if (!show_num_errors_dent)
680        goto out_err;
681
682    num_free_entries_dent = debugfs_create_u32("num_free_entries", 0444,
683            dma_debug_dent,
684            &num_free_entries);
685    if (!num_free_entries_dent)
686        goto out_err;
687
688    min_free_entries_dent = debugfs_create_u32("min_free_entries", 0444,
689            dma_debug_dent,
690            &min_free_entries);
691    if (!min_free_entries_dent)
692        goto out_err;
693
694    filter_dent = debugfs_create_file("driver_filter", 0644,
695                      dma_debug_dent, NULL, &filter_fops);
696    if (!filter_dent)
697        goto out_err;
698
699    return 0;
700
701out_err:
702    debugfs_remove_recursive(dma_debug_dent);
703
704    return -ENOMEM;
705}
706
707static int device_dma_allocations(struct device *dev, struct dma_debug_entry **out_entry)
708{
709    struct dma_debug_entry *entry;
710    unsigned long flags;
711    int count = 0, i;
712
713    local_irq_save(flags);
714
715    for (i = 0; i < HASH_SIZE; ++i) {
716        spin_lock(&dma_entry_hash[i].lock);
717        list_for_each_entry(entry, &dma_entry_hash[i].list, list) {
718            if (entry->dev == dev) {
719                count += 1;
720                *out_entry = entry;
721            }
722        }
723        spin_unlock(&dma_entry_hash[i].lock);
724    }
725
726    local_irq_restore(flags);
727
728    return count;
729}
730
731static int dma_debug_device_change(struct notifier_block *nb, unsigned long action, void *data)
732{
733    struct device *dev = data;
734    struct dma_debug_entry *uninitialized_var(entry);
735    int count;
736
737    if (global_disable)
738        return 0;
739
740    switch (action) {
741    case BUS_NOTIFY_UNBOUND_DRIVER:
742        count = device_dma_allocations(dev, &entry);
743        if (count == 0)
744            break;
745        err_printk(dev, entry, "DMA-API: device driver has pending "
746                "DMA allocations while released from device "
747                "[count=%d]\n"
748                "One of leaked entries details: "
749                "[device address=0x%016llx] [size=%llu bytes] "
750                "[mapped with %s] [mapped as %s]\n",
751            count, entry->dev_addr, entry->size,
752            dir2name[entry->direction], type2name[entry->type]);
753        break;
754    default:
755        break;
756    }
757
758    return 0;
759}
760
761void dma_debug_add_bus(struct bus_type *bus)
762{
763    struct notifier_block *nb;
764
765    if (global_disable)
766        return;
767
768    nb = kzalloc(sizeof(struct notifier_block), GFP_KERNEL);
769    if (nb == NULL) {
770        pr_err("dma_debug_add_bus: out of memory\n");
771        return;
772    }
773
774    nb->notifier_call = dma_debug_device_change;
775
776    bus_register_notifier(bus, nb);
777}
778
779/*
780 * Let the architectures decide how many entries should be preallocated.
781 */
782void dma_debug_init(u32 num_entries)
783{
784    int i;
785
786    if (global_disable)
787        return;
788
789    for (i = 0; i < HASH_SIZE; ++i) {
790        INIT_LIST_HEAD(&dma_entry_hash[i].list);
791        spin_lock_init(&dma_entry_hash[i].lock);
792    }
793
794    if (dma_debug_fs_init() != 0) {
795        pr_err("DMA-API: error creating debugfs entries - disabling\n");
796        global_disable = true;
797
798        return;
799    }
800
801    if (req_entries)
802        num_entries = req_entries;
803
804    if (prealloc_memory(num_entries) != 0) {
805        pr_err("DMA-API: debugging out of memory error - disabled\n");
806        global_disable = true;
807
808        return;
809    }
810
811    nr_total_entries = num_free_entries;
812
813    pr_info("DMA-API: debugging enabled by kernel config\n");
814}
815
816static __init int dma_debug_cmdline(char *str)
817{
818    if (!str)
819        return -EINVAL;
820
821    if (strncmp(str, "off", 3) == 0) {
822        pr_info("DMA-API: debugging disabled on kernel command line\n");
823        global_disable = true;
824    }
825
826    return 0;
827}
828
829static __init int dma_debug_entries_cmdline(char *str)
830{
831    int res;
832
833    if (!str)
834        return -EINVAL;
835
836    res = get_option(&str, &req_entries);
837
838    if (!res)
839        req_entries = 0;
840
841    return 0;
842}
843
844__setup("dma_debug=", dma_debug_cmdline);
845__setup("dma_debug_entries=", dma_debug_entries_cmdline);
846
847static void check_unmap(struct dma_debug_entry *ref)
848{
849    struct dma_debug_entry *entry;
850    struct hash_bucket *bucket;
851    unsigned long flags;
852
853    if (dma_mapping_error(ref->dev, ref->dev_addr)) {
854        err_printk(ref->dev, NULL, "DMA-API: device driver tries "
855               "to free an invalid DMA memory address\n");
856        return;
857    }
858
859    bucket = get_hash_bucket(ref, &flags);
860    entry = bucket_find_exact(bucket, ref);
861
862    if (!entry) {
863        err_printk(ref->dev, NULL, "DMA-API: device driver tries "
864               "to free DMA memory it has not allocated "
865               "[device address=0x%016llx] [size=%llu bytes]\n",
866               ref->dev_addr, ref->size);
867        goto out;
868    }
869
870    if (ref->size != entry->size) {
871        err_printk(ref->dev, entry, "DMA-API: device driver frees "
872               "DMA memory with different size "
873               "[device address=0x%016llx] [map size=%llu bytes] "
874               "[unmap size=%llu bytes]\n",
875               ref->dev_addr, entry->size, ref->size);
876    }
877
878    if (ref->type != entry->type) {
879        err_printk(ref->dev, entry, "DMA-API: device driver frees "
880               "DMA memory with wrong function "
881               "[device address=0x%016llx] [size=%llu bytes] "
882               "[mapped as %s] [unmapped as %s]\n",
883               ref->dev_addr, ref->size,
884               type2name[entry->type], type2name[ref->type]);
885    } else if ((entry->type == dma_debug_coherent) &&
886           (ref->paddr != entry->paddr)) {
887        err_printk(ref->dev, entry, "DMA-API: device driver frees "
888               "DMA memory with different CPU address "
889               "[device address=0x%016llx] [size=%llu bytes] "
890               "[cpu alloc address=0x%016llx] "
891               "[cpu free address=0x%016llx]",
892               ref->dev_addr, ref->size,
893               (unsigned long long)entry->paddr,
894               (unsigned long long)ref->paddr);
895    }
896
897    if (ref->sg_call_ents && ref->type == dma_debug_sg &&
898        ref->sg_call_ents != entry->sg_call_ents) {
899        err_printk(ref->dev, entry, "DMA-API: device driver frees "
900               "DMA sg list with different entry count "
901               "[map count=%d] [unmap count=%d]\n",
902               entry->sg_call_ents, ref->sg_call_ents);
903    }
904
905    /*
906     * This may be no bug in reality - but most implementations of the
907     * DMA API don't handle this properly, so check for it here
908     */
909    if (ref->direction != entry->direction) {
910        err_printk(ref->dev, entry, "DMA-API: device driver frees "
911               "DMA memory with different direction "
912               "[device address=0x%016llx] [size=%llu bytes] "
913               "[mapped with %s] [unmapped with %s]\n",
914               ref->dev_addr, ref->size,
915               dir2name[entry->direction],
916               dir2name[ref->direction]);
917    }
918
919    hash_bucket_del(entry);
920    dma_entry_free(entry);
921
922out:
923    put_hash_bucket(bucket, &flags);
924}
925
926static void check_for_stack(struct device *dev, void *addr)
927{
928    if (object_is_on_stack(addr))
929        err_printk(dev, NULL, "DMA-API: device driver maps memory from"
930                "stack [addr=%p]\n", addr);
931}
932
933static inline bool overlap(void *addr, unsigned long len, void *start, void *end)
934{
935    unsigned long a1 = (unsigned long)addr;
936    unsigned long b1 = a1 + len;
937    unsigned long a2 = (unsigned long)start;
938    unsigned long b2 = (unsigned long)end;
939
940    return !(b1 <= a2 || a1 >= b2);
941}
942
943static void check_for_illegal_area(struct device *dev, void *addr, unsigned long len)
944{
945    if (overlap(addr, len, _text, _etext) ||
946        overlap(addr, len, __start_rodata, __end_rodata))
947        err_printk(dev, NULL, "DMA-API: device driver maps memory from kernel text or rodata [addr=%p] [len=%lu]\n", addr, len);
948}
949
950static void check_sync(struct device *dev,
951               struct dma_debug_entry *ref,
952               bool to_cpu)
953{
954    struct dma_debug_entry *entry;
955    struct hash_bucket *bucket;
956    unsigned long flags;
957
958    bucket = get_hash_bucket(ref, &flags);
959
960    entry = bucket_find_contain(&bucket, ref, &flags);
961
962    if (!entry) {
963        err_printk(dev, NULL, "DMA-API: device driver tries "
964                "to sync DMA memory it has not allocated "
965                "[device address=0x%016llx] [size=%llu bytes]\n",
966                (unsigned long long)ref->dev_addr, ref->size);
967        goto out;
968    }
969
970    if (ref->size > entry->size) {
971        err_printk(dev, entry, "DMA-API: device driver syncs"
972                " DMA memory outside allocated range "
973                "[device address=0x%016llx] "
974                "[allocation size=%llu bytes] "
975                "[sync offset+size=%llu]\n",
976                entry->dev_addr, entry->size,
977                ref->size);
978    }
979
980    if (entry->direction == DMA_BIDIRECTIONAL)
981        goto out;
982
983    if (ref->direction != entry->direction) {
984        err_printk(dev, entry, "DMA-API: device driver syncs "
985                "DMA memory with different direction "
986                "[device address=0x%016llx] [size=%llu bytes] "
987                "[mapped with %s] [synced with %s]\n",
988                (unsigned long long)ref->dev_addr, entry->size,
989                dir2name[entry->direction],
990                dir2name[ref->direction]);
991    }
992
993    if (to_cpu && !(entry->direction == DMA_FROM_DEVICE) &&
994              !(ref->direction == DMA_TO_DEVICE))
995        err_printk(dev, entry, "DMA-API: device driver syncs "
996                "device read-only DMA memory for cpu "
997                "[device address=0x%016llx] [size=%llu bytes] "
998                "[mapped with %s] [synced with %s]\n",
999                (unsigned long long)ref->dev_addr, entry->size,
1000                dir2name[entry->direction],
1001                dir2name[ref->direction]);
1002
1003    if (!to_cpu && !(entry->direction == DMA_TO_DEVICE) &&
1004               !(ref->direction == DMA_FROM_DEVICE))
1005        err_printk(dev, entry, "DMA-API: device driver syncs "
1006                "device write-only DMA memory to device "
1007                "[device address=0x%016llx] [size=%llu bytes] "
1008                "[mapped with %s] [synced with %s]\n",
1009                (unsigned long long)ref->dev_addr, entry->size,
1010                dir2name[entry->direction],
1011                dir2name[ref->direction]);
1012
1013out:
1014    put_hash_bucket(bucket, &flags);
1015}
1016
1017void debug_dma_map_page(struct device *dev, struct page *page, size_t offset,
1018            size_t size, int direction, dma_addr_t dma_addr,
1019            bool map_single)
1020{
1021    struct dma_debug_entry *entry;
1022
1023    if (unlikely(global_disable))
1024        return;
1025
1026    if (unlikely(dma_mapping_error(dev, dma_addr)))
1027        return;
1028
1029    entry = dma_entry_alloc();
1030    if (!entry)
1031        return;
1032
1033    entry->dev = dev;
1034    entry->type = dma_debug_page;
1035    entry->paddr = page_to_phys(page) + offset;
1036    entry->dev_addr = dma_addr;
1037    entry->size = size;
1038    entry->direction = direction;
1039
1040    if (map_single)
1041        entry->type = dma_debug_single;
1042
1043    if (!PageHighMem(page)) {
1044        void *addr = page_address(page) + offset;
1045
1046        check_for_stack(dev, addr);
1047        check_for_illegal_area(dev, addr, size);
1048    }
1049
1050    add_dma_entry(entry);
1051}
1052EXPORT_SYMBOL(debug_dma_map_page);
1053
1054void debug_dma_unmap_page(struct device *dev, dma_addr_t addr,
1055              size_t size, int direction, bool map_single)
1056{
1057    struct dma_debug_entry ref = {
1058        .type = dma_debug_page,
1059        .dev = dev,
1060        .dev_addr = addr,
1061        .size = size,
1062        .direction = direction,
1063    };
1064
1065    if (unlikely(global_disable))
1066        return;
1067
1068    if (map_single)
1069        ref.type = dma_debug_single;
1070
1071    check_unmap(&ref);
1072}
1073EXPORT_SYMBOL(debug_dma_unmap_page);
1074
1075void debug_dma_map_sg(struct device *dev, struct scatterlist *sg,
1076              int nents, int mapped_ents, int direction)
1077{
1078    struct dma_debug_entry *entry;
1079    struct scatterlist *s;
1080    int i;
1081
1082    if (unlikely(global_disable))
1083        return;
1084
1085    for_each_sg(sg, s, mapped_ents, i) {
1086        entry = dma_entry_alloc();
1087        if (!entry)
1088            return;
1089
1090        entry->type = dma_debug_sg;
1091        entry->dev = dev;
1092        entry->paddr = sg_phys(s);
1093        entry->size = sg_dma_len(s);
1094        entry->dev_addr = sg_dma_address(s);
1095        entry->direction = direction;
1096        entry->sg_call_ents = nents;
1097        entry->sg_mapped_ents = mapped_ents;
1098
1099        if (!PageHighMem(sg_page(s))) {
1100            check_for_stack(dev, sg_virt(s));
1101            check_for_illegal_area(dev, sg_virt(s), sg_dma_len(s));
1102        }
1103
1104        add_dma_entry(entry);
1105    }
1106}
1107EXPORT_SYMBOL(debug_dma_map_sg);
1108
1109static int get_nr_mapped_entries(struct device *dev,
1110                 struct dma_debug_entry *ref)
1111{
1112    struct dma_debug_entry *entry;
1113    struct hash_bucket *bucket;
1114    unsigned long flags;
1115    int mapped_ents;
1116
1117    bucket = get_hash_bucket(ref, &flags);
1118    entry = bucket_find_exact(bucket, ref);
1119    mapped_ents = 0;
1120
1121    if (entry)
1122        mapped_ents = entry->sg_mapped_ents;
1123    put_hash_bucket(bucket, &flags);
1124
1125    return mapped_ents;
1126}
1127
1128void debug_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
1129            int nelems, int dir)
1130{
1131    struct scatterlist *s;
1132    int mapped_ents = 0, i;
1133
1134    if (unlikely(global_disable))
1135        return;
1136
1137    for_each_sg(sglist, s, nelems, i) {
1138
1139        struct dma_debug_entry ref = {
1140            .type = dma_debug_sg,
1141            .dev = dev,
1142            .paddr = sg_phys(s),
1143            .dev_addr = sg_dma_address(s),
1144            .size = sg_dma_len(s),
1145            .direction = dir,
1146            .sg_call_ents = nelems,
1147        };
1148
1149        if (mapped_ents && i >= mapped_ents)
1150            break;
1151
1152        if (!i)
1153            mapped_ents = get_nr_mapped_entries(dev, &ref);
1154
1155        check_unmap(&ref);
1156    }
1157}
1158EXPORT_SYMBOL(debug_dma_unmap_sg);
1159
1160void debug_dma_alloc_coherent(struct device *dev, size_t size,
1161                  dma_addr_t dma_addr, void *virt)
1162{
1163    struct dma_debug_entry *entry;
1164
1165    if (unlikely(global_disable))
1166        return;
1167
1168    if (unlikely(virt == NULL))
1169        return;
1170
1171    entry = dma_entry_alloc();
1172    if (!entry)
1173        return;
1174
1175    entry->type = dma_debug_coherent;
1176    entry->dev = dev;
1177    entry->paddr = virt_to_phys(virt);
1178    entry->size = size;
1179    entry->dev_addr = dma_addr;
1180    entry->direction = DMA_BIDIRECTIONAL;
1181
1182    add_dma_entry(entry);
1183}
1184EXPORT_SYMBOL(debug_dma_alloc_coherent);
1185
1186void debug_dma_free_coherent(struct device *dev, size_t size,
1187             void *virt, dma_addr_t addr)
1188{
1189    struct dma_debug_entry ref = {
1190        .type = dma_debug_coherent,
1191        .dev = dev,
1192        .paddr = virt_to_phys(virt),
1193        .dev_addr = addr,
1194        .size = size,
1195        .direction = DMA_BIDIRECTIONAL,
1196    };
1197
1198    if (unlikely(global_disable))
1199        return;
1200
1201    check_unmap(&ref);
1202}
1203EXPORT_SYMBOL(debug_dma_free_coherent);
1204
1205void debug_dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_handle,
1206                   size_t size, int direction)
1207{
1208    struct dma_debug_entry ref;
1209
1210    if (unlikely(global_disable))
1211        return;
1212
1213    ref.type = dma_debug_single;
1214    ref.dev = dev;
1215    ref.dev_addr = dma_handle;
1216    ref.size = size;
1217    ref.direction = direction;
1218    ref.sg_call_ents = 0;
1219
1220    check_sync(dev, &ref, true);
1221}
1222EXPORT_SYMBOL(debug_dma_sync_single_for_cpu);
1223
1224void debug_dma_sync_single_for_device(struct device *dev,
1225                      dma_addr_t dma_handle, size_t size,
1226                      int direction)
1227{
1228    struct dma_debug_entry ref;
1229
1230    if (unlikely(global_disable))
1231        return;
1232
1233    ref.type = dma_debug_single;
1234    ref.dev = dev;
1235    ref.dev_addr = dma_handle;
1236    ref.size = size;
1237    ref.direction = direction;
1238    ref.sg_call_ents = 0;
1239
1240    check_sync(dev, &ref, false);
1241}
1242EXPORT_SYMBOL(debug_dma_sync_single_for_device);
1243
1244void debug_dma_sync_single_range_for_cpu(struct device *dev,
1245                     dma_addr_t dma_handle,
1246                     unsigned long offset, size_t size,
1247                     int direction)
1248{
1249    struct dma_debug_entry ref;
1250
1251    if (unlikely(global_disable))
1252        return;
1253
1254    ref.type = dma_debug_single;
1255    ref.dev = dev;
1256    ref.dev_addr = dma_handle;
1257    ref.size = offset + size;
1258    ref.direction = direction;
1259    ref.sg_call_ents = 0;
1260
1261    check_sync(dev, &ref, true);
1262}
1263EXPORT_SYMBOL(debug_dma_sync_single_range_for_cpu);
1264
1265void debug_dma_sync_single_range_for_device(struct device *dev,
1266                        dma_addr_t dma_handle,
1267                        unsigned long offset,
1268                        size_t size, int direction)
1269{
1270    struct dma_debug_entry ref;
1271
1272    if (unlikely(global_disable))
1273        return;
1274
1275    ref.type = dma_debug_single;
1276    ref.dev = dev;
1277    ref.dev_addr = dma_handle;
1278    ref.size = offset + size;
1279    ref.direction = direction;
1280    ref.sg_call_ents = 0;
1281
1282    check_sync(dev, &ref, false);
1283}
1284EXPORT_SYMBOL(debug_dma_sync_single_range_for_device);
1285
1286void debug_dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
1287                   int nelems, int direction)
1288{
1289    struct scatterlist *s;
1290    int mapped_ents = 0, i;
1291
1292    if (unlikely(global_disable))
1293        return;
1294
1295    for_each_sg(sg, s, nelems, i) {
1296
1297        struct dma_debug_entry ref = {
1298            .type = dma_debug_sg,
1299            .dev = dev,
1300            .paddr = sg_phys(s),
1301            .dev_addr = sg_dma_address(s),
1302            .size = sg_dma_len(s),
1303            .direction = direction,
1304            .sg_call_ents = nelems,
1305        };
1306
1307        if (!i)
1308            mapped_ents = get_nr_mapped_entries(dev, &ref);
1309
1310        if (i >= mapped_ents)
1311            break;
1312
1313        check_sync(dev, &ref, true);
1314    }
1315}
1316EXPORT_SYMBOL(debug_dma_sync_sg_for_cpu);
1317
1318void debug_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
1319                  int nelems, int direction)
1320{
1321    struct scatterlist *s;
1322    int mapped_ents = 0, i;
1323
1324    if (unlikely(global_disable))
1325        return;
1326
1327    for_each_sg(sg, s, nelems, i) {
1328
1329        struct dma_debug_entry ref = {
1330            .type = dma_debug_sg,
1331            .dev = dev,
1332            .paddr = sg_phys(s),
1333            .dev_addr = sg_dma_address(s),
1334            .size = sg_dma_len(s),
1335            .direction = direction,
1336            .sg_call_ents = nelems,
1337        };
1338        if (!i)
1339            mapped_ents = get_nr_mapped_entries(dev, &ref);
1340
1341        if (i >= mapped_ents)
1342            break;
1343
1344        check_sync(dev, &ref, false);
1345    }
1346}
1347EXPORT_SYMBOL(debug_dma_sync_sg_for_device);
1348
1349static int __init dma_debug_driver_setup(char *str)
1350{
1351    int i;
1352
1353    for (i = 0; i < NAME_MAX_LEN - 1; ++i, ++str) {
1354        current_driver_name[i] = *str;
1355        if (*str == 0)
1356            break;
1357    }
1358
1359    if (current_driver_name[0])
1360        pr_info("DMA-API: enable driver filter for driver [%s]\n",
1361            current_driver_name);
1362
1363
1364    return 1;
1365}
1366__setup("dma_debug_driver=", dma_debug_driver_setup);
1367

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