diff options
| -rw-r--r-- | lib/dma-debug.c | 188 |
1 files changed, 187 insertions, 1 deletions
diff --git a/lib/dma-debug.c b/lib/dma-debug.c index 20d6cdbcacd..d0cb47a4211 100644 --- a/lib/dma-debug.c +++ b/lib/dma-debug.c @@ -17,10 +17,13 @@ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA */ +#include <linux/dma-mapping.h> #include <linux/dma-debug.h> #include <linux/spinlock.h> #include <linux/debugfs.h> +#include <linux/device.h> #include <linux/types.h> +#include <linux/sched.h> #include <linux/list.h> #include <linux/slab.h> @@ -50,7 +53,7 @@ struct dma_debug_entry { struct hash_bucket { struct list_head list; spinlock_t lock; -} __cacheline_aligned_in_smp; +} ____cacheline_aligned_in_smp; /* Hash list to save the allocated dma addresses */ static struct hash_bucket dma_entry_hash[HASH_SIZE]; @@ -85,6 +88,36 @@ 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 const char *type2name[4] = { "single", "page", + "scather-gather", "coherent" }; + +static const char *dir2name[4] = { "DMA_BIDIRECTIONAL", "DMA_TO_DEVICE", + "DMA_FROM_DEVICE", "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. + */ +#define err_printk(dev, format, arg...) do { \ + error_count += 1; \ + if (show_all_errors || show_num_errors > 0) { \ + WARN(1, "%s %s: " format, \ + dev_driver_string(dev), \ + dev_name(dev) , ## arg); \ + } \ + if (!show_all_errors && show_num_errors > 0) \ + show_num_errors -= 1; \ + } while (0); + /* * Hash related functions * @@ -380,3 +413,156 @@ static __init int dma_debug_entries_cmdline(char *str) __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; + + if (dma_mapping_error(ref->dev, ref->dev_addr)) + return; + + bucket = get_hash_bucket(ref, &flags); + entry = hash_bucket_find(bucket, ref); + + if (!entry) { + err_printk(ref->dev, "DMA-API: device driver tries " + "to free DMA memory it has not allocated " + "[device address=0x%016llx] [size=%llu bytes]\n", + ref->dev_addr, ref->size); + goto out; + } + + if (ref->size != entry->size) { + err_printk(ref->dev, "DMA-API: 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, "DMA-API: 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) && + (ref->paddr != entry->paddr)) { + err_printk(ref->dev, "DMA-API: device driver frees " + "DMA memory with different CPU address " + "[device address=0x%016llx] [size=%llu bytes] " + "[cpu alloc address=%p] [cpu free address=%p]", + ref->dev_addr, ref->size, + (void *)entry->paddr, (void *)ref->paddr); + } + + if (ref->sg_call_ents && ref->type == dma_debug_sg && + ref->sg_call_ents != entry->sg_call_ents) { + err_printk(ref->dev, "DMA-API: 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, "DMA-API: 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]); + } + + hash_bucket_del(entry); + dma_entry_free(entry); + +out: + put_hash_bucket(bucket, &flags); +} + +static void check_for_stack(struct device *dev, void *addr) +{ + if (object_is_on_stack(addr)) + err_printk(dev, "DMA-API: device driver maps memory from stack" + " [addr=%p]\n", addr); +} + +static void check_sync(struct device *dev, dma_addr_t addr, + u64 size, u64 offset, int direction, bool to_cpu) +{ + struct dma_debug_entry ref = { + .dev = dev, + .dev_addr = addr, + .size = size, + .direction = direction, + }; + struct dma_debug_entry *entry; + struct hash_bucket *bucket; + unsigned long flags; + + bucket = get_hash_bucket(&ref, &flags); + + entry = hash_bucket_find(bucket, &ref); + + if (!entry) { + err_printk(dev, "DMA-API: device driver tries " + "to sync DMA memory it has not allocated " + "[device address=0x%016llx] [size=%llu bytes]\n", + addr, size); + goto out; + } + + if ((offset + size) > entry->size) { + err_printk(dev, "DMA-API: device driver syncs" + " DMA memory outside allocated range " + "[device address=0x%016llx] " + "[allocation size=%llu bytes] [sync offset=%llu] " + "[sync size=%llu]\n", entry->dev_addr, entry->size, + offset, size); + } + + if (direction != entry->direction) { + err_printk(dev, "DMA-API: device driver syncs " + "DMA memory with different direction " + "[device address=0x%016llx] [size=%llu bytes] " + "[mapped with %s] [synced with %s]\n", + addr, entry->size, + dir2name[entry->direction], + dir2name[direction]); + } + + if (entry->direction == DMA_BIDIRECTIONAL) + goto out; + + if (to_cpu && !(entry->direction == DMA_FROM_DEVICE) && + !(direction == DMA_TO_DEVICE)) + err_printk(dev, "DMA-API: device driver syncs " + "device read-only DMA memory for cpu " + "[device address=0x%016llx] [size=%llu bytes] " + "[mapped with %s] [synced with %s]\n", + addr, entry->size, + dir2name[entry->direction], + dir2name[direction]); + + if (!to_cpu && !(entry->direction == DMA_TO_DEVICE) && + !(direction == DMA_FROM_DEVICE)) + err_printk(dev, "DMA-API: device driver syncs " + "device write-only DMA memory to device " + "[device address=0x%016llx] [size=%llu bytes] " + "[mapped with %s] [synced with %s]\n", + addr, entry->size, + dir2name[entry->direction], + dir2name[direction]); + +out: + put_hash_bucket(bucket, &flags); + +} + |