dma-debug: update DMA debug API to better handle multiple mappings of a buffer

[platform/adaptation/renesas_rcar/renesas_kernel.git] / lib / dma-debug.c

diff --git a/lib/dma-debug.c b/lib/dma-debug.c
index d84beb9..d87a17a 100644 (file)
--- a/lib/dma-debug.c
+++ b/lib/dma-debug.c
@@ -45,6 +45,12 @@ enum {
        dma_debug_coherent,
 };
 
+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 {
@@ -57,6 +63,7 @@ struct dma_debug_entry {
        int              direction;
        int              sg_call_ents;
        int              sg_mapped_ents;
+       enum map_err_types  map_err_type;
 #ifdef CONFIG_STACKTRACE
        struct           stack_trace stacktrace;
        unsigned long    st_entries[DMA_DEBUG_STACKTRACE_ENTRIES];
@@ -114,6 +121,12 @@ 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[4] = { "single", "page",
                                    "scather-gather", "coherent" };
 
@@ -376,11 +389,12 @@ void debug_dma_dump_mappings(struct device *dev)
                list_for_each_entry(entry, &bucket->list, list) {
                        if (!dev || dev == entry->dev) {
                                dev_info(entry->dev,
-                                        "%s idx %d P=%Lx D=%Lx L=%Lx %s\n",
+                                        "%s idx %d P=%Lx D=%Lx L=%Lx %s %s\n",
                                         type2name[entry->type], idx,
                                         (unsigned long long)entry->paddr,
                                         entry->dev_addr, entry->size,
-                                        dir2name[entry->direction]);
+                                        dir2name[entry->direction],
+                                        maperr2str[entry->map_err_type]);
                        }
                }
 
@@ -844,21 +858,25 @@ static void check_unmap(struct dma_debug_entry *ref)
        struct hash_bucket *bucket;
        unsigned long flags;
 
-       if (dma_mapping_error(ref->dev, ref->dev_addr)) {
-               err_printk(ref->dev, NULL, "DMA-API: device driver tries "
-                          "to free an invalid DMA memory address\n");
-               return;
-       }
-
        bucket = get_hash_bucket(ref, &flags);
        entry = bucket_find_exact(bucket, ref);
 
        if (!entry) {
-               err_printk(ref->dev, NULL, "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;
+               /* 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,
+                                  "DMA-API: device driver tries to free an "
+                                  "invalid DMA memory address\n");
+               } else {
+                       err_printk(ref->dev, NULL,
+                                  "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);
+               }
+               return;
        }
 
        if (ref->size != entry->size) {
@@ -910,10 +928,18 @@ static void check_unmap(struct dma_debug_entry *ref)
                           dir2name[ref->direction]);
        }
 
+       if (entry->map_err_type == MAP_ERR_NOT_CHECKED) {
+               err_printk(ref->dev, entry,
+                          "DMA-API: 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);
 
-out:
        put_hash_bucket(bucket, &flags);
 }
 
@@ -1017,7 +1043,7 @@ void debug_dma_map_page(struct device *dev, struct page *page, size_t offset,
        if (unlikely(global_disable))
                return;
 
-       if (unlikely(dma_mapping_error(dev, dma_addr)))
+       if (dma_mapping_error(dev, dma_addr))
                return;
 
        entry = dma_entry_alloc();
@@ -1030,6 +1056,7 @@ void debug_dma_map_page(struct device *dev, struct page *page, size_t offset,
        entry->dev_addr  = dma_addr;
        entry->size      = size;
        entry->direction = direction;
+       entry->map_err_type = MAP_ERR_NOT_CHECKED;
 
        if (map_single)
                entry->type = dma_debug_single;
@@ -1045,6 +1072,44 @@ void debug_dma_map_page(struct device *dev, struct page *page, size_t offset,
 }
 EXPORT_SYMBOL(debug_dma_map_page);
 
+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(global_disable))
+               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, bool map_single)
 {