Adding upstream version 5.10.209.upstream/5.10.209upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1610 insertions, 0 deletions

diff --git a/kernel/dma/debug.c b/kernel/dma/debug.c
new file mode 100644
index 000000000..026398308
--- /dev/null
+++ b/kernel/dma/debug.c
@@ -0,0 +1,1610 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (C) 2008 Advanced Micro Devices, Inc.
+ *
+ * Author: Joerg Roedel <joerg.roedel@amd.com>
+ */
+
+#define pr_fmt(fmt)	"DMA-API: " fmt
+
+#include <linux/sched/task_stack.h>
+#include <linux/scatterlist.h>
+#include <linux/dma-map-ops.h>
+#include <linux/sched/task.h>
+#include <linux/stacktrace.h>
+#include <linux/spinlock.h>
+#include <linux/vmalloc.h>
+#include <linux/debugfs.h>
+#include <linux/uaccess.h>
+#include <linux/export.h>
+#include <linux/device.h>
+#include <linux/types.h>
+#include <linux/sched.h>
+#include <linux/ctype.h>
+#include <linux/list.h>
+#include <linux/slab.h>
+#include <asm/sections.h>
+#include "debug.h"
+
+#define HASH_SIZE       16384ULL
+#define HASH_FN_SHIFT   13
+#define HASH_FN_MASK    (HASH_SIZE - 1)
+
+#define PREALLOC_DMA_DEBUG_ENTRIES (1 << 16)
+/* If the pool runs out, add this many new entries at once */
+#define DMA_DEBUG_DYNAMIC_ENTRIES (PAGE_SIZE / sizeof(struct dma_debug_entry))
+
+enum {
+	dma_debug_single,
+	dma_debug_sg,
+	dma_debug_coherent,
+	dma_debug_resource,
+};
+
+enum map_err_types {
+	MAP_ERR_CHECK_NOT_APPLICABLE,
+	MAP_ERR_NOT_CHECKED,
+	MAP_ERR_CHECKED,
+};
+
+#define DMA_DEBUG_STACKTRACE_ENTRIES 5
+
+/**
+ * struct dma_debug_entry - track a dma_map* or dma_alloc_coherent mapping
+ * @list: node on pre-allocated free_entries list
+ * @dev: 'dev' argument to dma_map_{page|single|sg} or dma_alloc_coherent
+ * @size: length of the mapping
+ * @type: single, page, sg, coherent
+ * @direction: enum dma_data_direction
+ * @sg_call_ents: 'nents' from dma_map_sg
+ * @sg_mapped_ents: 'mapped_ents' from dma_map_sg
+ * @pfn: page frame of the start address
+ * @offset: offset of mapping relative to pfn
+ * @map_err_type: track whether dma_mapping_error() was checked
+ * @stacktrace: support backtraces when a violation is detected
+ */
+struct dma_debug_entry {
+	struct list_head list;
+	struct device    *dev;
+	u64              dev_addr;
+	u64              size;
+	int              type;
+	int              direction;
+	int		 sg_call_ents;
+	int		 sg_mapped_ents;
+	unsigned long	 pfn;
+	size_t		 offset;
+	enum map_err_types  map_err_type;
+#ifdef CONFIG_STACKTRACE
+	unsigned int	stack_len;
+	unsigned long	stack_entries[DMA_DEBUG_STACKTRACE_ENTRIES];
+#endif
+} ____cacheline_aligned_in_smp;
+
+typedef bool (*match_fn)(struct dma_debug_entry *, struct dma_debug_entry *);
+
+struct hash_bucket {
+	struct list_head list;
+	spinlock_t lock;
+};
+
+/* Hash list to save the allocated dma addresses */
+static struct hash_bucket dma_entry_hash[HASH_SIZE];
+/* List of pre-allocated dma_debug_entry's */
+static LIST_HEAD(free_entries);
+/* Lock for the list above */
+static DEFINE_SPINLOCK(free_entries_lock);
+
+/* Global disable flag - will be set in case of an error */
+static bool global_disable __read_mostly;
+
+/* Early initialization disable flag, set at the end of dma_debug_init */
+static bool dma_debug_initialized __read_mostly;
+
+static inline bool dma_debug_disabled(void)
+{
+	return global_disable || !dma_debug_initialized;
+}
+
+/* Global error count */
+static u32 error_count;
+
+/* Global error show enable*/
+static u32 show_all_errors __read_mostly;
+/* Number of errors to show */
+static u32 show_num_errors = 1;
+
+static u32 num_free_entries;
+static u32 min_free_entries;
+static u32 nr_total_entries;
+
+/* number of preallocated entries requested by kernel cmdline */
+static u32 nr_prealloc_entries = PREALLOC_DMA_DEBUG_ENTRIES;
+
+/* per-driver filter related state */
+
+#define NAME_MAX_LEN	64
+
+static char                  current_driver_name[NAME_MAX_LEN] __read_mostly;
+static struct device_driver *current_driver                    __read_mostly;
+
+static DEFINE_RWLOCK(driver_name_lock);
+
+static const char *const maperr2str[] = {
+	[MAP_ERR_CHECK_NOT_APPLICABLE] = "dma map error check not applicable",
+	[MAP_ERR_NOT_CHECKED] = "dma map error not checked",
+	[MAP_ERR_CHECKED] = "dma map error checked",
+};
+
+static const char *type2name[] = {
+	[dma_debug_single] = "single",
+	[dma_debug_sg] = "scather-gather",
+	[dma_debug_coherent] = "coherent",
+	[dma_debug_resource] = "resource",
+};
+
+static const char *dir2name[] = {
+	[DMA_BIDIRECTIONAL]	= "DMA_BIDIRECTIONAL",
+	[DMA_TO_DEVICE]		= "DMA_TO_DEVICE",
+	[DMA_FROM_DEVICE]	= "DMA_FROM_DEVICE",
+	[DMA_NONE]		= "DMA_NONE",
+};
+
+/*
+ * The access to some variables in this macro is racy. We can't use atomic_t
+ * here because all these variables are exported to debugfs. Some of them even
+ * writeable. This is also the reason why a lock won't help much. But anyway,
+ * the races are no big deal. Here is why:
+ *
+ *   error_count: the addition is racy, but the worst thing that can happen is
+ *                that we don't count some errors
+ *   show_num_errors: the subtraction is racy. Also no big deal because in
+ *                    worst case this will result in one warning more in the
+ *                    system log than the user configured. This variable is
+ *                    writeable via debugfs.
+ */
+static inline void dump_entry_trace(struct dma_debug_entry *entry)
+{
+#ifdef CONFIG_STACKTRACE
+	if (entry) {
+		pr_warn("Mapped at:\n");
+		stack_trace_print(entry->stack_entries, entry->stack_len, 0);
+	}
+#endif
+}
+
+static bool driver_filter(struct device *dev)
+{
+	struct device_driver *drv;
+	unsigned long flags;
+	bool ret;
+
+	/* driver filter off */
+	if (likely(!current_driver_name[0]))
+		return true;
+
+	/* driver filter on and initialized */
+	if (current_driver && dev && dev->driver == current_driver)
+		return true;
+
+	/* driver filter on, but we can't filter on a NULL device... */
+	if (!dev)
+		return false;
+
+	if (current_driver || !current_driver_name[0])
+		return false;
+
+	/* driver filter on but not yet initialized */
+	drv = dev->driver;
+	if (!drv)
+		return false;
+
+	/* lock to protect against change of current_driver_name */
+	read_lock_irqsave(&driver_name_lock, flags);
+
+	ret = false;
+	if (drv->name &&
+	    strncmp(current_driver_name, drv->name, NAME_MAX_LEN - 1) == 0) {
+		current_driver = drv;
+		ret = true;
+	}
+
+	read_unlock_irqrestore(&driver_name_lock, flags);
+
+	return ret;
+}
+
+#define err_printk(dev, entry, format, arg...) do {			\
+		error_count += 1;					\
+		if (driver_filter(dev) &&				\
+		    (show_all_errors || show_num_errors > 0)) {		\
+			WARN(1, pr_fmt("%s %s: ") format,		\
+			     dev ? dev_driver_string(dev) : "NULL",	\
+			     dev ? dev_name(dev) : "NULL", ## arg);	\
+			dump_entry_trace(entry);			\
+		}							\
+		if (!show_all_errors && show_num_errors > 0)		\
+			show_num_errors -= 1;				\
+	} while (0);
+
+/*
+ * Hash related functions
+ *
+ * Every DMA-API request is saved into a struct dma_debug_entry. To
+ * have quick access to these structs they are stored into a hash.
+ */
+static int hash_fn(struct dma_debug_entry *entry)
+{
+	/*
+	 * Hash function is based on the dma address.
+	 * We use bits 20-27 here as the index into the hash
+	 */
+	return (entry->dev_addr >> HASH_FN_SHIFT) & HASH_FN_MASK;
+}
+
+/*
+ * Request exclusive access to a hash bucket for a given dma_debug_entry.
+ */
+static struct hash_bucket *get_hash_bucket(struct dma_debug_entry *entry,
+					   unsigned long *flags)
+	__acquires(&dma_entry_hash[idx].lock)
+{
+	int idx = hash_fn(entry);
+	unsigned long __flags;
+
+	spin_lock_irqsave(&dma_entry_hash[idx].lock, __flags);
+	*flags = __flags;
+	return &dma_entry_hash[idx];
+}
+
+/*
+ * Give up exclusive access to the hash bucket
+ */
+static void put_hash_bucket(struct hash_bucket *bucket,
+			    unsigned long flags)
+	__releases(&bucket->lock)
+{
+	spin_unlock_irqrestore(&bucket->lock, flags);
+}
+
+static bool exact_match(struct dma_debug_entry *a, struct dma_debug_entry *b)
+{
+	return ((a->dev_addr == b->dev_addr) &&
+		(a->dev == b->dev)) ? true : false;
+}
+
+static bool containing_match(struct dma_debug_entry *a,
+			     struct dma_debug_entry *b)
+{
+	if (a->dev != b->dev)
+		return false;
+
+	if ((b->dev_addr <= a->dev_addr) &&
+	    ((b->dev_addr + b->size) >= (a->dev_addr + a->size)))
+		return true;
+
+	return false;
+}
+
+/*
+ * Search a given entry in the hash bucket list
+ */
+static struct dma_debug_entry *__hash_bucket_find(struct hash_bucket *bucket,
+						  struct dma_debug_entry *ref,
+						  match_fn match)
+{
+	struct dma_debug_entry *entry, *ret = NULL;
+	int matches = 0, match_lvl, last_lvl = -1;
+
+	list_for_each_entry(entry, &bucket->list, list) {
+		if (!match(ref, entry))
+			continue;
+
+		/*
+		 * Some drivers map the same physical address multiple
+		 * times. Without a hardware IOMMU this results in the
+		 * same device addresses being put into the dma-debug
+		 * hash multiple times too. This can result in false
+		 * positives being reported. Therefore we implement a
+		 * best-fit algorithm here which returns the entry from
+		 * the hash which fits best to the reference value
+		 * instead of the first-fit.
+		 */
+		matches += 1;
+		match_lvl = 0;
+		entry->size         == ref->size         ? ++match_lvl : 0;
+		entry->type         == ref->type         ? ++match_lvl : 0;
+		entry->direction    == ref->direction    ? ++match_lvl : 0;
+		entry->sg_call_ents == ref->sg_call_ents ? ++match_lvl : 0;
+
+		if (match_lvl == 4) {
+			/* perfect-fit - return the result */
+			return entry;
+		} else if (match_lvl > last_lvl) {
+			/*
+			 * We found an entry that fits better then the
+			 * previous one or it is the 1st match.
+			 */
+			last_lvl = match_lvl;
+			ret      = entry;
+		}
+	}
+
+	/*
+	 * If we have multiple matches but no perfect-fit, just return
+	 * NULL.
+	 */
+	ret = (matches == 1) ? ret : NULL;
+
+	return ret;
+}
+
+static struct dma_debug_entry *bucket_find_exact(struct hash_bucket *bucket,
+						 struct dma_debug_entry *ref)
+{
+	return __hash_bucket_find(bucket, ref, exact_match);
+}
+
+static struct dma_debug_entry *bucket_find_contain(struct hash_bucket **bucket,
+						   struct dma_debug_entry *ref,
+						   unsigned long *flags)
+{
+
+	unsigned int max_range = dma_get_max_seg_size(ref->dev);
+	struct dma_debug_entry *entry, index = *ref;
+	unsigned int range = 0;
+
+	while (range <= max_range) {
+		entry = __hash_bucket_find(*bucket, ref, containing_match);
+
+		if (entry)
+			return entry;
+
+		/*
+		 * Nothing found, go back a hash bucket
+		 */
+		put_hash_bucket(*bucket, *flags);
+		range          += (1 << HASH_FN_SHIFT);
+		index.dev_addr -= (1 << HASH_FN_SHIFT);
+		*bucket = get_hash_bucket(&index, flags);
+	}
+
+	return NULL;
+}
+
+/*
+ * Add an entry to a hash bucket
+ */
+static void hash_bucket_add(struct hash_bucket *bucket,
+			    struct dma_debug_entry *entry)
+{
+	list_add_tail(&entry->list, &bucket->list);
+}
+
+/*
+ * Remove entry from a hash bucket list
+ */
+static void hash_bucket_del(struct dma_debug_entry *entry)
+{
+	list_del(&entry->list);
+}
+
+static unsigned long long phys_addr(struct dma_debug_entry *entry)
+{
+	if (entry->type == dma_debug_resource)
+		return __pfn_to_phys(entry->pfn) + entry->offset;
+
+	return page_to_phys(pfn_to_page(entry->pfn)) + entry->offset;
+}
+
+/*
+ * Dump mapping entries for debugging purposes
+ */
+void debug_dma_dump_mappings(struct device *dev)
+{
+	int idx;
+
+	for (idx = 0; idx < HASH_SIZE; idx++) {
+		struct hash_bucket *bucket = &dma_entry_hash[idx];
+		struct dma_debug_entry *entry;
+		unsigned long flags;
+
+		spin_lock_irqsave(&bucket->lock, flags);
+
+		list_for_each_entry(entry, &bucket->list, list) {
+			if (!dev || dev == entry->dev) {
+				dev_info(entry->dev,
+					 "%s idx %d P=%Lx N=%lx D=%Lx L=%Lx %s %s\n",
+					 type2name[entry->type], idx,
+					 phys_addr(entry), entry->pfn,
+					 entry->dev_addr, entry->size,
+					 dir2name[entry->direction],
+					 maperr2str[entry->map_err_type]);
+			}
+		}
+
+		spin_unlock_irqrestore(&bucket->lock, flags);
+		cond_resched();
+	}
+}
+
+/*
+ * For each mapping (initial cacheline in the case of
+ * dma_alloc_coherent/dma_map_page, initial cacheline in each page of a
+ * scatterlist, or the cacheline specified in dma_map_single) insert
+ * into this tree using the cacheline as the key. At
+ * dma_unmap_{single|sg|page} or dma_free_coherent delete the entry.  If
+ * the entry already exists at insertion time add a tag as a reference
+ * count for the overlapping mappings.  For now, the overlap tracking
+ * just ensures that 'unmaps' balance 'maps' before marking the
+ * cacheline idle, but we should also be flagging overlaps as an API
+ * violation.
+ *
+ * Memory usage is mostly constrained by the maximum number of available
+ * dma-debug entries in that we need a free dma_debug_entry before
+ * inserting into the tree.  In the case of dma_map_page and
+ * dma_alloc_coherent there is only one dma_debug_entry and one
+ * dma_active_cacheline entry to track per event.  dma_map_sg(), on the
+ * other hand, consumes a single dma_debug_entry, but inserts 'nents'
+ * entries into the tree.
+ */
+static RADIX_TREE(dma_active_cacheline, GFP_ATOMIC);
+static DEFINE_SPINLOCK(radix_lock);
+#define ACTIVE_CACHELINE_MAX_OVERLAP ((1 << RADIX_TREE_MAX_TAGS) - 1)
+#define CACHELINE_PER_PAGE_SHIFT (PAGE_SHIFT - L1_CACHE_SHIFT)
+#define CACHELINES_PER_PAGE (1 << CACHELINE_PER_PAGE_SHIFT)
+
+static phys_addr_t to_cacheline_number(struct dma_debug_entry *entry)
+{
+	return (entry->pfn << CACHELINE_PER_PAGE_SHIFT) +
+		(entry->offset >> L1_CACHE_SHIFT);
+}
+
+static int active_cacheline_read_overlap(phys_addr_t cln)
+{
+	int overlap = 0, i;
+
+	for (i = RADIX_TREE_MAX_TAGS - 1; i >= 0; i--)
+		if (radix_tree_tag_get(&dma_active_cacheline, cln, i))
+			overlap |= 1 << i;
+	return overlap;
+}
+
+static int active_cacheline_set_overlap(phys_addr_t cln, int overlap)
+{
+	int i;
+
+	if (overlap > ACTIVE_CACHELINE_MAX_OVERLAP || overlap < 0)
+		return overlap;
+
+	for (i = RADIX_TREE_MAX_TAGS - 1; i >= 0; i--)
+		if (overlap & 1 << i)
+			radix_tree_tag_set(&dma_active_cacheline, cln, i);
+		else
+			radix_tree_tag_clear(&dma_active_cacheline, cln, i);
+
+	return overlap;
+}
+
+static void active_cacheline_inc_overlap(phys_addr_t cln)
+{
+	int overlap = active_cacheline_read_overlap(cln);
+
+	overlap = active_cacheline_set_overlap(cln, ++overlap);
+
+	/* If we overflowed the overlap counter then we're potentially
+	 * leaking dma-mappings.
+	 */
+	WARN_ONCE(overlap > ACTIVE_CACHELINE_MAX_OVERLAP,
+		  pr_fmt("exceeded %d overlapping mappings of cacheline %pa\n"),
+		  ACTIVE_CACHELINE_MAX_OVERLAP, &cln);
+}
+
+static int active_cacheline_dec_overlap(phys_addr_t cln)
+{
+	int overlap = active_cacheline_read_overlap(cln);
+
+	return active_cacheline_set_overlap(cln, --overlap);
+}
+
+static int active_cacheline_insert(struct dma_debug_entry *entry)
+{
+	phys_addr_t cln = to_cacheline_number(entry);
+	unsigned long flags;
+	int rc;
+
+	/* If the device is not writing memory then we don't have any
+	 * concerns about the cpu consuming stale data.  This mitigates
+	 * legitimate usages of overlapping mappings.
+	 */
+	if (entry->direction == DMA_TO_DEVICE)
+		return 0;
+
+	spin_lock_irqsave(&radix_lock, flags);
+	rc = radix_tree_insert(&dma_active_cacheline, cln, entry);
+	if (rc == -EEXIST)
+		active_cacheline_inc_overlap(cln);
+	spin_unlock_irqrestore(&radix_lock, flags);
+
+	return rc;
+}
+
+static void active_cacheline_remove(struct dma_debug_entry *entry)
+{
+	phys_addr_t cln = to_cacheline_number(entry);
+	unsigned long flags;
+
+	/* ...mirror the insert case */
+	if (entry->direction == DMA_TO_DEVICE)
+		return;
+
+	spin_lock_irqsave(&radix_lock, flags);
+	/* since we are counting overlaps the final put of the
+	 * cacheline will occur when the overlap count is 0.
+	 * active_cacheline_dec_overlap() returns -1 in that case
+	 */
+	if (active_cacheline_dec_overlap(cln) < 0)
+		radix_tree_delete(&dma_active_cacheline, cln);
+	spin_unlock_irqrestore(&radix_lock, flags);
+}
+
+/*
+ * Wrapper function for adding an entry to the hash.
+ * This function takes care of locking itself.
+ */
+static void add_dma_entry(struct dma_debug_entry *entry)
+{
+	struct hash_bucket *bucket;
+	unsigned long flags;
+	int rc;
+
+	bucket = get_hash_bucket(entry, &flags);
+	hash_bucket_add(bucket, entry);
+	put_hash_bucket(bucket, flags);
+
+	rc = active_cacheline_insert(entry);
+	if (rc == -ENOMEM) {
+		pr_err_once("cacheline tracking ENOMEM, dma-debug disabled\n");
+		global_disable = true;
+	}
+
+	/* TODO: report -EEXIST errors here as overlapping mappings are
+	 * not supported by the DMA API
+	 */
+}
+
+static int dma_debug_create_entries(gfp_t gfp)
+{
+	struct dma_debug_entry *entry;
+	int i;
+
+	entry = (void *)get_zeroed_page(gfp);
+	if (!entry)
+		return -ENOMEM;
+
+	for (i = 0; i < DMA_DEBUG_DYNAMIC_ENTRIES; i++)
+		list_add_tail(&entry[i].list, &free_entries);
+
+	num_free_entries += DMA_DEBUG_DYNAMIC_ENTRIES;
+	nr_total_entries += DMA_DEBUG_DYNAMIC_ENTRIES;
+
+	return 0;
+}
+
+static struct dma_debug_entry *__dma_entry_alloc(void)
+{
+	struct dma_debug_entry *entry;
+
+	entry = list_entry(free_entries.next, struct dma_debug_entry, list);
+	list_del(&entry->list);
+	memset(entry, 0, sizeof(*entry));
+
+	num_free_entries -= 1;
+	if (num_free_entries < min_free_entries)
+		min_free_entries = num_free_entries;
+
+	return entry;
+}
+
+/*
+ * This should be called outside of free_entries_lock scope to avoid potential
+ * deadlocks with serial consoles that use DMA.
+ */
+static void __dma_entry_alloc_check_leak(u32 nr_entries)
+{
+	u32 tmp = nr_entries % nr_prealloc_entries;
+
+	/* Shout each time we tick over some multiple of the initial pool */
+	if (tmp < DMA_DEBUG_DYNAMIC_ENTRIES) {
+		pr_info("dma_debug_entry pool grown to %u (%u00%%)\n",
+			nr_entries,
+			(nr_entries / nr_prealloc_entries));
+	}
+}
+
+/* struct dma_entry allocator
+ *
+ * The next two functions implement the allocator for
+ * struct dma_debug_entries.
+ */
+static struct dma_debug_entry *dma_entry_alloc(void)
+{
+	bool alloc_check_leak = false;
+	struct dma_debug_entry *entry;
+	unsigned long flags;
+	u32 nr_entries;
+
+	spin_lock_irqsave(&free_entries_lock, flags);
+	if (num_free_entries == 0) {
+		if (dma_debug_create_entries(GFP_ATOMIC)) {
+			global_disable = true;
+			spin_unlock_irqrestore(&free_entries_lock, flags);
+			pr_err("debugging out of memory - disabling\n");
+			return NULL;
+		}
+		alloc_check_leak = true;
+		nr_entries = nr_total_entries;
+	}
+
+	entry = __dma_entry_alloc();
+
+	spin_unlock_irqrestore(&free_entries_lock, flags);
+
+	if (alloc_check_leak)
+		__dma_entry_alloc_check_leak(nr_entries);
+
+#ifdef CONFIG_STACKTRACE
+	entry->stack_len = stack_trace_save(entry->stack_entries,
+					    ARRAY_SIZE(entry->stack_entries),
+					    1);
+#endif
+	return entry;
+}
+
+static void dma_entry_free(struct dma_debug_entry *entry)
+{
+	unsigned long flags;
+
+	active_cacheline_remove(entry);
+
+	/*
+	 * add to beginning of the list - this way the entries are
+	 * more likely cache hot when they are reallocated.
+	 */
+	spin_lock_irqsave(&free_entries_lock, flags);
+	list_add(&entry->list, &free_entries);
+	num_free_entries += 1;
+	spin_unlock_irqrestore(&free_entries_lock, flags);
+}
+
+/*
+ * DMA-API debugging init code
+ *
+ * The init code does two things:
+ *   1. Initialize core data structures
+ *   2. Preallocate a given number of dma_debug_entry structs
+ */
+
+static ssize_t filter_read(struct file *file, char __user *user_buf,
+			   size_t count, loff_t *ppos)
+{
+	char buf[NAME_MAX_LEN + 1];
+	unsigned long flags;
+	int len;
+
+	if (!current_driver_name[0])
+		return 0;
+
+	/*
+	 * We can't copy to userspace directly because current_driver_name can
+	 * only be read under the driver_name_lock with irqs disabled. So
+	 * create a temporary copy first.
+	 */
+	read_lock_irqsave(&driver_name_lock, flags);
+	len = scnprintf(buf, NAME_MAX_LEN + 1, "%s\n", current_driver_name);
+	read_unlock_irqrestore(&driver_name_lock, flags);
+
+	return simple_read_from_buffer(user_buf, count, ppos, buf, len);
+}
+
+static ssize_t filter_write(struct file *file, const char __user *userbuf,
+			    size_t count, loff_t *ppos)
+{
+	char buf[NAME_MAX_LEN];
+	unsigned long flags;
+	size_t len;
+	int i;
+
+	/*
+	 * We can't copy from userspace directly. Access to
+	 * current_driver_name is protected with a write_lock with irqs
+	 * disabled. Since copy_from_user can fault and may sleep we
+	 * need to copy to temporary buffer first
+	 */
+	len = min(count, (size_t)(NAME_MAX_LEN - 1));
+	if (copy_from_user(buf, userbuf, len))
+		return -EFAULT;
+
+	buf[len] = 0;
+
+	write_lock_irqsave(&driver_name_lock, flags);
+
+	/*
+	 * Now handle the string we got from userspace very carefully.
+	 * The rules are:
+	 *         - only use the first token we got
+	 *         - token delimiter is everything looking like a space
+	 *           character (' ', '\n', '\t' ...)
+	 *
+	 */
+	if (!isalnum(buf[0])) {
+		/*
+		 * If the first character userspace gave us is not
+		 * alphanumerical then assume the filter should be
+		 * switched off.
+		 */
+		if (current_driver_name[0])
+			pr_info("switching off dma-debug driver filter\n");
+		current_driver_name[0] = 0;
+		current_driver = NULL;
+		goto out_unlock;
+	}
+
+	/*
+	 * Now parse out the first token and use it as the name for the
+	 * driver to filter for.
+	 */
+	for (i = 0; i < NAME_MAX_LEN - 1; ++i) {
+		current_driver_name[i] = buf[i];
+		if (isspace(buf[i]) || buf[i] == ' ' || buf[i] == 0)
+			break;
+	}
+	current_driver_name[i] = 0;
+	current_driver = NULL;
+
+	pr_info("enable driver filter for driver [%s]\n",
+		current_driver_name);
+
+out_unlock:
+	write_unlock_irqrestore(&driver_name_lock, flags);
+
+	return count;
+}
+
+static const struct file_operations filter_fops = {
+	.read  = filter_read,
+	.write = filter_write,
+	.llseek = default_llseek,
+};
+
+static int dump_show(struct seq_file *seq, void *v)
+{
+	int idx;
+
+	for (idx = 0; idx < HASH_SIZE; idx++) {
+		struct hash_bucket *bucket = &dma_entry_hash[idx];
+		struct dma_debug_entry *entry;
+		unsigned long flags;
+
+		spin_lock_irqsave(&bucket->lock, flags);
+		list_for_each_entry(entry, &bucket->list, list) {
+			seq_printf(seq,
+				   "%s %s %s idx %d P=%llx N=%lx D=%llx L=%llx %s %s\n",
+				   dev_name(entry->dev),
+				   dev_driver_string(entry->dev),
+				   type2name[entry->type], idx,
+				   phys_addr(entry), entry->pfn,
+				   entry->dev_addr, entry->size,
+				   dir2name[entry->direction],
+				   maperr2str[entry->map_err_type]);
+		}
+		spin_unlock_irqrestore(&bucket->lock, flags);
+	}
+	return 0;
+}
+DEFINE_SHOW_ATTRIBUTE(dump);
+
+static int __init dma_debug_fs_init(void)
+{
+	struct dentry *dentry = debugfs_create_dir("dma-api", NULL);
+
+	debugfs_create_bool("disabled", 0444, dentry, &global_disable);
+	debugfs_create_u32("error_count", 0444, dentry, &error_count);
+	debugfs_create_u32("all_errors", 0644, dentry, &show_all_errors);
+	debugfs_create_u32("num_errors", 0644, dentry, &show_num_errors);
+	debugfs_create_u32("num_free_entries", 0444, dentry, &num_free_entries);
+	debugfs_create_u32("min_free_entries", 0444, dentry, &min_free_entries);
+	debugfs_create_u32("nr_total_entries", 0444, dentry, &nr_total_entries);
+	debugfs_create_file("driver_filter", 0644, dentry, NULL, &filter_fops);
+	debugfs_create_file("dump", 0444, dentry, NULL, &dump_fops);
+
+	return 0;
+}
+core_initcall_sync(dma_debug_fs_init);
+
+static int device_dma_allocations(struct device *dev, struct dma_debug_entry **out_entry)
+{
+	struct dma_debug_entry *entry;
+	unsigned long flags;
+	int count = 0, i;
+
+	for (i = 0; i < HASH_SIZE; ++i) {
+		spin_lock_irqsave(&dma_entry_hash[i].lock, flags);
+		list_for_each_entry(entry, &dma_entry_hash[i].list, list) {
+			if (entry->dev == dev) {
+				count += 1;
+				*out_entry = entry;
+			}
+		}
+		spin_unlock_irqrestore(&dma_entry_hash[i].lock, flags);
+	}
+
+	return count;
+}
+
+static int dma_debug_device_change(struct notifier_block *nb, unsigned long action, void *data)
+{
+	struct device *dev = data;
+	struct dma_debug_entry *entry;
+	int count;
+
+	if (dma_debug_disabled())
+		return 0;
+
+	switch (action) {
+	case BUS_NOTIFY_UNBOUND_DRIVER:
+		count = device_dma_allocations(dev, &entry);
+		if (count == 0)
+			break;
+		err_printk(dev, entry, "device driver has pending "
+				"DMA allocations while released from device "
+				"[count=%d]\n"
+				"One of leaked entries details: "
+				"[device address=0x%016llx] [size=%llu bytes] "
+				"[mapped with %s] [mapped as %s]\n",
+			count, entry->dev_addr, entry->size,
+			dir2name[entry->direction], type2name[entry->type]);
+		break;
+	default:
+		break;
+	}
+
+	return 0;
+}
+
+void dma_debug_add_bus(struct bus_type *bus)
+{
+	struct notifier_block *nb;
+
+	if (dma_debug_disabled())
+		return;
+
+	nb = kzalloc(sizeof(struct notifier_block), GFP_KERNEL);
+	if (nb == NULL) {
+		pr_err("dma_debug_add_bus: out of memory\n");
+		return;
+	}
+
+	nb->notifier_call = dma_debug_device_change;
+
+	bus_register_notifier(bus, nb);
+}
+
+static int dma_debug_init(void)
+{
+	int i, nr_pages;
+
+	/* Do not use dma_debug_initialized here, since we really want to be
+	 * called to set dma_debug_initialized
+	 */
+	if (global_disable)
+		return 0;
+
+	for (i = 0; i < HASH_SIZE; ++i) {
+		INIT_LIST_HEAD(&dma_entry_hash[i].list);
+		spin_lock_init(&dma_entry_hash[i].lock);
+	}
+
+	nr_pages = DIV_ROUND_UP(nr_prealloc_entries, DMA_DEBUG_DYNAMIC_ENTRIES);
+	for (i = 0; i < nr_pages; ++i)
+		dma_debug_create_entries(GFP_KERNEL);
+	if (num_free_entries >= nr_prealloc_entries) {
+		pr_info("preallocated %d debug entries\n", nr_total_entries);
+	} else if (num_free_entries > 0) {
+		pr_warn("%d debug entries requested but only %d allocated\n",
+			nr_prealloc_entries, nr_total_entries);
+	} else {
+		pr_err("debugging out of memory error - disabled\n");
+		global_disable = true;
+
+		return 0;
+	}
+	min_free_entries = num_free_entries;
+
+	dma_debug_initialized = true;
+
+	pr_info("debugging enabled by kernel config\n");
+	return 0;
+}
+core_initcall(dma_debug_init);
+
+static __init int dma_debug_cmdline(char *str)
+{
+	if (!str)
+		return -EINVAL;
+
+	if (strncmp(str, "off", 3) == 0) {
+		pr_info("debugging disabled on kernel command line\n");
+		global_disable = true;
+	}
+
+	return 1;
+}
+
+static __init int dma_debug_entries_cmdline(char *str)
+{
+	if (!str)
+		return -EINVAL;
+	if (!get_option(&str, &nr_prealloc_entries))
+		nr_prealloc_entries = PREALLOC_DMA_DEBUG_ENTRIES;
+	return 1;
+}
+
+__setup("dma_debug=", dma_debug_cmdline);
+__setup("dma_debug_entries=", dma_debug_entries_cmdline);
+
+static void check_unmap(struct dma_debug_entry *ref)
+{
+	struct dma_debug_entry *entry;
+	struct hash_bucket *bucket;
+	unsigned long flags;
+
+	bucket = get_hash_bucket(ref, &flags);
+	entry = bucket_find_exact(bucket, ref);
+
+	if (!entry) {
+		/* must drop lock before calling dma_mapping_error */
+		put_hash_bucket(bucket, flags);
+
+		if (dma_mapping_error(ref->dev, ref->dev_addr)) {
+			err_printk(ref->dev, NULL,
+				   "device driver tries to free an "
+				   "invalid DMA memory address\n");
+		} else {
+			err_printk(ref->dev, NULL,
+				   "device driver tries to free DMA "
+				   "memory it has not allocated [device "
+				   "address=0x%016llx] [size=%llu bytes]\n",
+				   ref->dev_addr, ref->size);
+		}
+		return;
+	}
+
+	if (ref->size != entry->size) {
+		err_printk(ref->dev, entry, "device driver frees "
+			   "DMA memory with different size "
+			   "[device address=0x%016llx] [map size=%llu bytes] "
+			   "[unmap size=%llu bytes]\n",
+			   ref->dev_addr, entry->size, ref->size);
+	}
+
+	if (ref->type != entry->type) {
+		err_printk(ref->dev, entry, "device driver frees "
+			   "DMA memory with wrong function "
+			   "[device address=0x%016llx] [size=%llu bytes] "
+			   "[mapped as %s] [unmapped as %s]\n",
+			   ref->dev_addr, ref->size,
+			   type2name[entry->type], type2name[ref->type]);
+	} else if ((entry->type == dma_debug_coherent) &&
+		   (phys_addr(ref) != phys_addr(entry))) {
+		err_printk(ref->dev, entry, "device driver frees "
+			   "DMA memory with different CPU address "
+			   "[device address=0x%016llx] [size=%llu bytes] "
+			   "[cpu alloc address=0x%016llx] "
+			   "[cpu free address=0x%016llx]",
+			   ref->dev_addr, ref->size,
+			   phys_addr(entry),
+			   phys_addr(ref));
+	}
+
+	if (ref->sg_call_ents && ref->type == dma_debug_sg &&
+	    ref->sg_call_ents != entry->sg_call_ents) {
+		err_printk(ref->dev, entry, "device driver frees "
+			   "DMA sg list with different entry count "
+			   "[map count=%d] [unmap count=%d]\n",
+			   entry->sg_call_ents, ref->sg_call_ents);
+	}
+
+	/*
+	 * This may be no bug in reality - but most implementations of the
+	 * DMA API don't handle this properly, so check for it here
+	 */
+	if (ref->direction != entry->direction) {
+		err_printk(ref->dev, entry, "device driver frees "
+			   "DMA memory with different direction "
+			   "[device address=0x%016llx] [size=%llu bytes] "
+			   "[mapped with %s] [unmapped with %s]\n",
+			   ref->dev_addr, ref->size,
+			   dir2name[entry->direction],
+			   dir2name[ref->direction]);
+	}
+
+	/*
+	 * Drivers should use dma_mapping_error() to check the returned
+	 * addresses of dma_map_single() and dma_map_page().
+	 * If not, print this warning message. See Documentation/core-api/dma-api.rst.
+	 */
+	if (entry->map_err_type == MAP_ERR_NOT_CHECKED) {
+		err_printk(ref->dev, entry,
+			   "device driver failed to check map error"
+			   "[device address=0x%016llx] [size=%llu bytes] "
+			   "[mapped as %s]",
+			   ref->dev_addr, ref->size,
+			   type2name[entry->type]);
+	}
+
+	hash_bucket_del(entry);
+	dma_entry_free(entry);
+
+	put_hash_bucket(bucket, flags);
+}
+
+static void check_for_stack(struct device *dev,
+			    struct page *page, size_t offset)
+{
+	void *addr;
+	struct vm_struct *stack_vm_area = task_stack_vm_area(current);
+
+	if (!stack_vm_area) {
+		/* Stack is direct-mapped. */
+		if (PageHighMem(page))
+			return;
+		addr = page_address(page) + offset;
+		if (object_is_on_stack(addr))
+			err_printk(dev, NULL, "device driver maps memory from stack [addr=%p]\n", addr);
+	} else {
+		/* Stack is vmalloced. */
+		int i;
+
+		for (i = 0; i < stack_vm_area->nr_pages; i++) {
+			if (page != stack_vm_area->pages[i])
+				continue;
+
+			addr = (u8 *)current->stack + i * PAGE_SIZE + offset;
+			err_printk(dev, NULL, "device driver maps memory from stack [probable addr=%p]\n", addr);
+			break;
+		}
+	}
+}
+
+static inline bool overlap(void *addr, unsigned long len, void *start, void *end)
+{
+	unsigned long a1 = (unsigned long)addr;
+	unsigned long b1 = a1 + len;
+	unsigned long a2 = (unsigned long)start;
+	unsigned long b2 = (unsigned long)end;
+
+	return !(b1 <= a2 || a1 >= b2);
+}
+
+static void check_for_illegal_area(struct device *dev, void *addr, unsigned long len)
+{
+	if (overlap(addr, len, _stext, _etext) ||
+	    overlap(addr, len, __start_rodata, __end_rodata))
+		err_printk(dev, NULL, "device driver maps memory from kernel text or rodata [addr=%p] [len=%lu]\n", addr, len);
+}
+
+static void check_sync(struct device *dev,
+		       struct dma_debug_entry *ref,
+		       bool to_cpu)
+{
+	struct dma_debug_entry *entry;
+	struct hash_bucket *bucket;
+	unsigned long flags;
+
+	bucket = get_hash_bucket(ref, &flags);
+
+	entry = bucket_find_contain(&bucket, ref, &flags);
+
+	if (!entry) {
+		err_printk(dev, NULL, "device driver tries "
+				"to sync DMA memory it has not allocated "
+				"[device address=0x%016llx] [size=%llu bytes]\n",
+				(unsigned long long)ref->dev_addr, ref->size);
+		goto out;
+	}
+
+	if (ref->size > entry->size) {
+		err_printk(dev, entry, "device driver syncs"
+				" DMA memory outside allocated range "
+				"[device address=0x%016llx] "
+				"[allocation size=%llu bytes] "
+				"[sync offset+size=%llu]\n",
+				entry->dev_addr, entry->size,
+				ref->size);
+	}
+
+	if (entry->direction == DMA_BIDIRECTIONAL)
+		goto out;
+
+	if (ref->direction != entry->direction) {
+		err_printk(dev, entry, "device driver syncs "
+				"DMA memory with different direction "
+				"[device address=0x%016llx] [size=%llu bytes] "
+				"[mapped with %s] [synced with %s]\n",
+				(unsigned long long)ref->dev_addr, entry->size,
+				dir2name[entry->direction],
+				dir2name[ref->direction]);
+	}
+
+	if (to_cpu && !(entry->direction == DMA_FROM_DEVICE) &&
+		      !(ref->direction == DMA_TO_DEVICE))
+		err_printk(dev, entry, "device driver syncs "
+				"device read-only DMA memory for cpu "
+				"[device address=0x%016llx] [size=%llu bytes] "
+				"[mapped with %s] [synced with %s]\n",
+				(unsigned long long)ref->dev_addr, entry->size,
+				dir2name[entry->direction],
+				dir2name[ref->direction]);
+
+	if (!to_cpu && !(entry->direction == DMA_TO_DEVICE) &&
+		       !(ref->direction == DMA_FROM_DEVICE))
+		err_printk(dev, entry, "device driver syncs "
+				"device write-only DMA memory to device "
+				"[device address=0x%016llx] [size=%llu bytes] "
+				"[mapped with %s] [synced with %s]\n",
+				(unsigned long long)ref->dev_addr, entry->size,
+				dir2name[entry->direction],
+				dir2name[ref->direction]);
+
+	if (ref->sg_call_ents && ref->type == dma_debug_sg &&
+	    ref->sg_call_ents != entry->sg_call_ents) {
+		err_printk(ref->dev, entry, "device driver syncs "
+			   "DMA sg list with different entry count "
+			   "[map count=%d] [sync count=%d]\n",
+			   entry->sg_call_ents, ref->sg_call_ents);
+	}
+
+out:
+	put_hash_bucket(bucket, flags);
+}
+
+static void check_sg_segment(struct device *dev, struct scatterlist *sg)
+{
+#ifdef CONFIG_DMA_API_DEBUG_SG
+	unsigned int max_seg = dma_get_max_seg_size(dev);
+	u64 start, end, boundary = dma_get_seg_boundary(dev);
+
+	/*
+	 * Either the driver forgot to set dma_parms appropriately, or
+	 * whoever generated the list forgot to check them.
+	 */
+	if (sg->length > max_seg)
+		err_printk(dev, NULL, "mapping sg segment longer than device claims to support [len=%u] [max=%u]\n",
+			   sg->length, max_seg);
+	/*
+	 * In some cases this could potentially be the DMA API
+	 * implementation's fault, but it would usually imply that
+	 * the scatterlist was built inappropriately to begin with.
+	 */
+	start = sg_dma_address(sg);
+	end = start + sg_dma_len(sg) - 1;
+	if ((start ^ end) & ~boundary)
+		err_printk(dev, NULL, "mapping sg segment across boundary [start=0x%016llx] [end=0x%016llx] [boundary=0x%016llx]\n",
+			   start, end, boundary);
+#endif
+}
+
+void debug_dma_map_single(struct device *dev, const void *addr,
+			    unsigned long len)
+{
+	if (unlikely(dma_debug_disabled()))
+		return;
+
+	if (!virt_addr_valid(addr))
+		err_printk(dev, NULL, "device driver maps memory from invalid area [addr=%p] [len=%lu]\n",
+			   addr, len);
+
+	if (is_vmalloc_addr(addr))
+		err_printk(dev, NULL, "device driver maps memory from vmalloc area [addr=%p] [len=%lu]\n",
+			   addr, len);
+}
+EXPORT_SYMBOL(debug_dma_map_single);
+
+void debug_dma_map_page(struct device *dev, struct page *page, size_t offset,
+			size_t size, int direction, dma_addr_t dma_addr)
+{
+	struct dma_debug_entry *entry;
+
+	if (unlikely(dma_debug_disabled()))
+		return;
+
+	if (dma_mapping_error(dev, dma_addr))
+		return;
+
+	entry = dma_entry_alloc();
+	if (!entry)
+		return;
+
+	entry->dev       = dev;
+	entry->type      = dma_debug_single;
+	entry->pfn	 = page_to_pfn(page);
+	entry->offset	 = offset;
+	entry->dev_addr  = dma_addr;
+	entry->size      = size;
+	entry->direction = direction;
+	entry->map_err_type = MAP_ERR_NOT_CHECKED;
+
+	check_for_stack(dev, page, offset);
+
+	if (!PageHighMem(page)) {
+		void *addr = page_address(page) + offset;
+
+		check_for_illegal_area(dev, addr, size);
+	}
+
+	add_dma_entry(entry);
+}
+
+void debug_dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
+{
+	struct dma_debug_entry ref;
+	struct dma_debug_entry *entry;
+	struct hash_bucket *bucket;
+	unsigned long flags;
+
+	if (unlikely(dma_debug_disabled()))
+		return;
+
+	ref.dev = dev;
+	ref.dev_addr = dma_addr;
+	bucket = get_hash_bucket(&ref, &flags);
+
+	list_for_each_entry(entry, &bucket->list, list) {
+		if (!exact_match(&ref, entry))
+			continue;
+
+		/*
+		 * The same physical address can be mapped multiple
+		 * times. Without a hardware IOMMU this results in the
+		 * same device addresses being put into the dma-debug
+		 * hash multiple times too. This can result in false
+		 * positives being reported. Therefore we implement a
+		 * best-fit algorithm here which updates the first entry
+		 * from the hash which fits the reference value and is
+		 * not currently listed as being checked.
+		 */
+		if (entry->map_err_type == MAP_ERR_NOT_CHECKED) {
+			entry->map_err_type = MAP_ERR_CHECKED;
+			break;
+		}
+	}
+
+	put_hash_bucket(bucket, flags);
+}
+EXPORT_SYMBOL(debug_dma_mapping_error);
+
+void debug_dma_unmap_page(struct device *dev, dma_addr_t addr,
+			  size_t size, int direction)
+{
+	struct dma_debug_entry ref = {
+		.type           = dma_debug_single,
+		.dev            = dev,
+		.dev_addr       = addr,
+		.size           = size,
+		.direction      = direction,
+	};
+
+	if (unlikely(dma_debug_disabled()))
+		return;
+	check_unmap(&ref);
+}
+
+void debug_dma_map_sg(struct device *dev, struct scatterlist *sg,
+		      int nents, int mapped_ents, int direction)
+{
+	struct dma_debug_entry *entry;
+	struct scatterlist *s;
+	int i;
+
+	if (unlikely(dma_debug_disabled()))
+		return;
+
+	for_each_sg(sg, s, nents, i) {
+		check_for_stack(dev, sg_page(s), s->offset);
+		if (!PageHighMem(sg_page(s)))
+			check_for_illegal_area(dev, sg_virt(s), s->length);
+	}
+
+	for_each_sg(sg, s, mapped_ents, i) {
+		entry = dma_entry_alloc();
+		if (!entry)
+			return;
+
+		entry->type           = dma_debug_sg;
+		entry->dev            = dev;
+		entry->pfn	      = page_to_pfn(sg_page(s));
+		entry->offset	      = s->offset;
+		entry->size           = sg_dma_len(s);
+		entry->dev_addr       = sg_dma_address(s);
+		entry->direction      = direction;
+		entry->sg_call_ents   = nents;
+		entry->sg_mapped_ents = mapped_ents;
+
+		check_sg_segment(dev, s);
+
+		add_dma_entry(entry);
+	}
+}
+
+static int get_nr_mapped_entries(struct device *dev,
+				 struct dma_debug_entry *ref)
+{
+	struct dma_debug_entry *entry;
+	struct hash_bucket *bucket;
+	unsigned long flags;
+	int mapped_ents;
+
+	bucket       = get_hash_bucket(ref, &flags);
+	entry        = bucket_find_exact(bucket, ref);
+	mapped_ents  = 0;
+
+	if (entry)
+		mapped_ents = entry->sg_mapped_ents;
+	put_hash_bucket(bucket, flags);
+
+	return mapped_ents;
+}
+
+void debug_dma_unmap_sg(struct device *dev, struct scatterlist *sglist,
+			int nelems, int dir)
+{
+	struct scatterlist *s;
+	int mapped_ents = 0, i;
+
+	if (unlikely(dma_debug_disabled()))
+		return;
+
+	for_each_sg(sglist, s, nelems, i) {
+
+		struct dma_debug_entry ref = {
+			.type           = dma_debug_sg,
+			.dev            = dev,
+			.pfn		= page_to_pfn(sg_page(s)),
+			.offset		= s->offset,
+			.dev_addr       = sg_dma_address(s),
+			.size           = sg_dma_len(s),
+			.direction      = dir,
+			.sg_call_ents   = nelems,
+		};
+
+		if (mapped_ents && i >= mapped_ents)
+			break;
+
+		if (!i)
+			mapped_ents = get_nr_mapped_entries(dev, &ref);
+
+		check_unmap(&ref);
+	}
+}
+
+void debug_dma_alloc_coherent(struct device *dev, size_t size,
+			      dma_addr_t dma_addr, void *virt)
+{
+	struct dma_debug_entry *entry;
+
+	if (unlikely(dma_debug_disabled()))
+		return;
+
+	if (unlikely(virt == NULL))
+		return;
+
+	/* handle vmalloc and linear addresses */
+	if (!is_vmalloc_addr(virt) && !virt_addr_valid(virt))
+		return;
+
+	entry = dma_entry_alloc();
+	if (!entry)
+		return;
+
+	entry->type      = dma_debug_coherent;
+	entry->dev       = dev;
+	entry->offset	 = offset_in_page(virt);
+	entry->size      = size;
+	entry->dev_addr  = dma_addr;
+	entry->direction = DMA_BIDIRECTIONAL;
+
+	if (is_vmalloc_addr(virt))
+		entry->pfn = vmalloc_to_pfn(virt);
+	else
+		entry->pfn = page_to_pfn(virt_to_page(virt));
+
+	add_dma_entry(entry);
+}
+
+void debug_dma_free_coherent(struct device *dev, size_t size,
+			 void *virt, dma_addr_t addr)
+{
+	struct dma_debug_entry ref = {
+		.type           = dma_debug_coherent,
+		.dev            = dev,
+		.offset		= offset_in_page(virt),
+		.dev_addr       = addr,
+		.size           = size,
+		.direction      = DMA_BIDIRECTIONAL,
+	};
+
+	/* handle vmalloc and linear addresses */
+	if (!is_vmalloc_addr(virt) && !virt_addr_valid(virt))
+		return;
+
+	if (is_vmalloc_addr(virt))
+		ref.pfn = vmalloc_to_pfn(virt);
+	else
+		ref.pfn = page_to_pfn(virt_to_page(virt));
+
+	if (unlikely(dma_debug_disabled()))
+		return;
+
+	check_unmap(&ref);
+}
+
+void debug_dma_map_resource(struct device *dev, phys_addr_t addr, size_t size,
+			    int direction, dma_addr_t dma_addr)
+{
+	struct dma_debug_entry *entry;
+
+	if (unlikely(dma_debug_disabled()))
+		return;
+
+	entry = dma_entry_alloc();
+	if (!entry)
+		return;
+
+	entry->type		= dma_debug_resource;
+	entry->dev		= dev;
+	entry->pfn		= PHYS_PFN(addr);
+	entry->offset		= offset_in_page(addr);
+	entry->size		= size;
+	entry->dev_addr		= dma_addr;
+	entry->direction	= direction;
+	entry->map_err_type	= MAP_ERR_NOT_CHECKED;
+
+	add_dma_entry(entry);
+}
+
+void debug_dma_unmap_resource(struct device *dev, dma_addr_t dma_addr,
+			      size_t size, int direction)
+{
+	struct dma_debug_entry ref = {
+		.type           = dma_debug_resource,
+		.dev            = dev,
+		.dev_addr       = dma_addr,
+		.size           = size,
+		.direction      = direction,
+	};
+
+	if (unlikely(dma_debug_disabled()))
+		return;
+
+	check_unmap(&ref);
+}
+
+void debug_dma_sync_single_for_cpu(struct device *dev, dma_addr_t dma_handle,
+				   size_t size, int direction)
+{
+	struct dma_debug_entry ref;
+
+	if (unlikely(dma_debug_disabled()))
+		return;
+
+	ref.type         = dma_debug_single;
+	ref.dev          = dev;
+	ref.dev_addr     = dma_handle;
+	ref.size         = size;
+	ref.direction    = direction;
+	ref.sg_call_ents = 0;
+
+	check_sync(dev, &ref, true);
+}
+
+void debug_dma_sync_single_for_device(struct device *dev,
+				      dma_addr_t dma_handle, size_t size,
+				      int direction)
+{
+	struct dma_debug_entry ref;
+
+	if (unlikely(dma_debug_disabled()))
+		return;
+
+	ref.type         = dma_debug_single;
+	ref.dev          = dev;
+	ref.dev_addr     = dma_handle;
+	ref.size         = size;
+	ref.direction    = direction;
+	ref.sg_call_ents = 0;
+
+	check_sync(dev, &ref, false);
+}
+
+void debug_dma_sync_sg_for_cpu(struct device *dev, struct scatterlist *sg,
+			       int nelems, int direction)
+{
+	struct scatterlist *s;
+	int mapped_ents = 0, i;
+
+	if (unlikely(dma_debug_disabled()))
+		return;
+
+	for_each_sg(sg, s, nelems, i) {
+
+		struct dma_debug_entry ref = {
+			.type           = dma_debug_sg,
+			.dev            = dev,
+			.pfn		= page_to_pfn(sg_page(s)),
+			.offset		= s->offset,
+			.dev_addr       = sg_dma_address(s),
+			.size           = sg_dma_len(s),
+			.direction      = direction,
+			.sg_call_ents   = nelems,
+		};
+
+		if (!i)
+			mapped_ents = get_nr_mapped_entries(dev, &ref);
+
+		if (i >= mapped_ents)
+			break;
+
+		check_sync(dev, &ref, true);
+	}
+}
+
+void debug_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
+				  int nelems, int direction)
+{
+	struct scatterlist *s;
+	int mapped_ents = 0, i;
+
+	if (unlikely(dma_debug_disabled()))
+		return;
+
+	for_each_sg(sg, s, nelems, i) {
+
+		struct dma_debug_entry ref = {
+			.type           = dma_debug_sg,
+			.dev            = dev,
+			.pfn		= page_to_pfn(sg_page(s)),
+			.offset		= s->offset,
+			.dev_addr       = sg_dma_address(s),
+			.size           = sg_dma_len(s),
+			.direction      = direction,
+			.sg_call_ents   = nelems,
+		};
+		if (!i)
+			mapped_ents = get_nr_mapped_entries(dev, &ref);
+
+		if (i >= mapped_ents)
+			break;
+
+		check_sync(dev, &ref, false);
+	}
+}
+
+static int __init dma_debug_driver_setup(char *str)
+{
+	int i;
+
+	for (i = 0; i < NAME_MAX_LEN - 1; ++i, ++str) {
+		current_driver_name[i] = *str;
+		if (*str == 0)
+			break;
+	}
+
+	if (current_driver_name[0])
+		pr_info("enable driver filter for driver [%s]\n",
+			current_driver_name);
+
+
+	return 1;
+}
+__setup("dma_debug_driver=", dma_debug_driver_setup);