#include <linux/dma-debug.h>
#include <linux/spinlock.h>
#include <linux/debugfs.h>
+#include <linux/uaccess.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>
static struct dentry *show_num_errors_dent __read_mostly;
static struct dentry *num_free_entries_dent __read_mostly;
static struct dentry *min_free_entries_dent __read_mostly;
+static struct dentry *filter_dent __read_mostly;
+
+/* 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 *type2name[4] = { "single", "page",
"scather-gather", "coherent" };
{
#ifdef CONFIG_STACKTRACE
if (entry) {
- printk(KERN_WARNING "Mapped at:\n");
+ pr_warning("Mapped at:\n");
print_stack_trace(&entry->stacktrace, 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->driver == current_driver)
+ return true;
+
+ if (current_driver || !current_driver_name[0])
+ return false;
+
+ /* driver filter on but not yet initialized */
+ drv = get_driver(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);
+ put_driver(drv);
+
+ return ret;
+}
+
#define err_printk(dev, entry, format, arg...) do { \
error_count += 1; \
- if (show_all_errors || show_num_errors > 0) { \
+ if (driver_filter(dev) && \
+ (show_all_errors || show_num_errors > 0)) { \
WARN(1, "%s %s: " format, \
dev_driver_string(dev), \
dev_name(dev) , ## arg); \
static struct dma_debug_entry *hash_bucket_find(struct hash_bucket *bucket,
struct dma_debug_entry *ref)
{
- struct dma_debug_entry *entry;
+ struct dma_debug_entry *entry, *ret = NULL;
+ int matches = 0, match_lvl, last_lvl = 0;
list_for_each_entry(entry, &bucket->list, list) {
- if ((entry->dev_addr == ref->dev_addr) &&
- (entry->dev == ref->dev))
+ if ((entry->dev_addr != ref->dev_addr) ||
+ (entry->dev != ref->dev))
+ 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. Therfore 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 : match_lvl;
+ entry->type == ref->type ? ++match_lvl : match_lvl;
+ entry->direction == ref->direction ? ++match_lvl : match_lvl;
+
+ if (match_lvl == 3) {
+ /* perfect-fit - return the result */
return entry;
+ } else if (match_lvl > last_lvl) {
+ /*
+ * We found an entry that fits better then the
+ * previous one
+ */
+ last_lvl = match_lvl;
+ ret = entry;
+ }
}
- return NULL;
+ /*
+ * If we have multiple matches but no perfect-fit, just return
+ * NULL.
+ */
+ ret = (matches == 1) ? ret : NULL;
+
+ return ret;
}
/*
spin_lock_irqsave(&free_entries_lock, flags);
if (list_empty(&free_entries)) {
- printk(KERN_ERR "DMA-API: debugging out of memory "
- "- disabling\n");
+ pr_err("DMA-API: debugging out of memory - disabling\n");
global_disable = true;
goto out;
}
num_free_entries = num_entries;
min_free_entries = num_entries;
- printk(KERN_INFO "DMA-API: preallocated %d debug entries\n",
- num_entries);
+ pr_info("DMA-API: preallocated %d debug entries\n", num_entries);
return 0;
return -ENOMEM;
}
+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("DMA-API: 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; ++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("DMA-API: enable driver filter for driver [%s]\n",
+ current_driver_name);
+
+out_unlock:
+ write_unlock_irqrestore(&driver_name_lock, flags);
+
+ return count;
+}
+
+const struct file_operations filter_fops = {
+ .read = filter_read,
+ .write = filter_write,
+};
+
static int dma_debug_fs_init(void)
{
dma_debug_dent = debugfs_create_dir("dma-api", NULL);
if (!dma_debug_dent) {
- printk(KERN_ERR "DMA-API: can not create debugfs directory\n");
+ pr_err("DMA-API: can not create debugfs directory\n");
return -ENOMEM;
}
if (!min_free_entries_dent)
goto out_err;
+ filter_dent = debugfs_create_file("driver_filter", 0644,
+ dma_debug_dent, NULL, &filter_fops);
+ if (!filter_dent)
+ goto out_err;
+
return 0;
out_err:
unsigned long flags;
int count = 0, i;
+ local_irq_save(flags);
+
for (i = 0; i < HASH_SIZE; ++i) {
- spin_lock_irqsave(&dma_entry_hash[i].lock, flags);
+ spin_lock(&dma_entry_hash[i].lock);
list_for_each_entry(entry, &dma_entry_hash[i].list, list) {
if (entry->dev == dev)
count += 1;
}
- spin_unlock_irqrestore(&dma_entry_hash[i].lock, flags);
+ spin_unlock(&dma_entry_hash[i].lock);
}
+ local_irq_restore(flags);
+
return count;
}
nb = kzalloc(sizeof(struct notifier_block), GFP_KERNEL);
if (nb == NULL) {
- printk(KERN_ERR "dma_debug_add_bus: out of memory\n");
+ pr_err("dma_debug_add_bus: out of memory\n");
return;
}
}
if (dma_debug_fs_init() != 0) {
- printk(KERN_ERR "DMA-API: error creating debugfs entries "
- "- disabling\n");
+ pr_err("DMA-API: error creating debugfs entries - disabling\n");
global_disable = true;
return;
num_entries = req_entries;
if (prealloc_memory(num_entries) != 0) {
- printk(KERN_ERR "DMA-API: debugging out of memory error "
- "- disabled\n");
+ pr_err("DMA-API: debugging out of memory error - disabled\n");
global_disable = true;
return;
nr_total_entries = num_free_entries;
- printk(KERN_INFO "DMA-API: debugging enabled by kernel config\n");
+ pr_info("DMA-API: debugging enabled by kernel config\n");
}
static __init int dma_debug_cmdline(char *str)
return -EINVAL;
if (strncmp(str, "off", 3) == 0) {
- printk(KERN_INFO "DMA-API: debugging disabled on kernel "
- "command line\n");
+ pr_info("DMA-API: debugging disabled on kernel command line\n");
global_disable = true;
}
}
EXPORT_SYMBOL(debug_dma_map_sg);
+static int get_nr_mapped_entries(struct device *dev, struct scatterlist *s)
+{
+ struct dma_debug_entry *entry, ref;
+ struct hash_bucket *bucket;
+ unsigned long flags;
+ int mapped_ents;
+
+ ref.dev = dev;
+ ref.dev_addr = sg_dma_address(s);
+ ref.size = sg_dma_len(s),
+
+ bucket = get_hash_bucket(&ref, &flags);
+ entry = hash_bucket_find(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 dma_debug_entry *entry;
struct scatterlist *s;
int mapped_ents = 0, i;
- unsigned long flags;
if (unlikely(global_disable))
return;
if (mapped_ents && i >= mapped_ents)
break;
- if (mapped_ents == 0) {
- struct hash_bucket *bucket;
+ if (!i) {
ref.sg_call_ents = nelems;
- bucket = get_hash_bucket(&ref, &flags);
- entry = hash_bucket_find(bucket, &ref);
- if (entry)
- mapped_ents = entry->sg_mapped_ents;
- put_hash_bucket(bucket, &flags);
+ mapped_ents = get_nr_mapped_entries(dev, s);
}
check_unmap(&ref);
int nelems, int direction)
{
struct scatterlist *s;
- int i;
+ int mapped_ents = 0, i;
if (unlikely(global_disable))
return;
for_each_sg(sg, s, nelems, i) {
+ if (!i)
+ mapped_ents = get_nr_mapped_entries(dev, s);
+
+ if (i >= mapped_ents)
+ break;
+
check_sync(dev, sg_dma_address(s), sg_dma_len(s), 0,
direction, true);
}
int nelems, int direction)
{
struct scatterlist *s;
- int i;
+ int mapped_ents = 0, i;
if (unlikely(global_disable))
return;
for_each_sg(sg, s, nelems, i) {
+ if (!i)
+ mapped_ents = get_nr_mapped_entries(dev, s);
+
+ if (i >= mapped_ents)
+ break;
+
check_sync(dev, sg_dma_address(s), sg_dma_len(s), 0,
direction, false);
}
}
EXPORT_SYMBOL(debug_dma_sync_sg_for_device);
+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("DMA-API: enable driver filter for driver [%s]\n",
+ current_driver_name);
+
+
+ return 1;
+}
+__setup("dma_debug_driver=", dma_debug_driver_setup);
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