dma-debug: add function to dump dma mappings

This adds a function to dump the DMA mappings that the debugging code is aware of -- either for a single device, or for _all_ devices. This can be useful for debugging -- sticking a call to it in the DMA page fault handler, for example, to see if the faulting address _should_ be mapped or not, and hence work out whether it's IOMMU bugs we're seeing, or driver bugs. Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>

dma-debug: add function to dump dma mappings
This adds a function to dump the DMA mappings that the debugging code is aware of -- either for a single device, or for _all_ devices. This can be useful for debugging -- sticking a call to it in the DMA page fault handler, for example, to see if the faulting address _should_ be mapped or not, and hence work out whether it's IOMMU bugs we're seeing, or driver bugs. Signed-off-by: David Woodhouse <David.Woodhouse@intel.com>
David Woodhouse · Joerg Roedel
1 parent a31fba5d68
Showing 2 changed files with 36 additions and 0 deletions Side-by-side Diff
include/linux/dma-debug.h
lib/dma-debug.c
@@ -76,6 +76,8 @@
 					 struct scatterlist *sg,
 					 int nelems, int direction);
  
+extern void debug_dma_dump_mappings(struct device *dev);
+
 #else /* CONFIG_DMA_API_DEBUG */
  
 static inline void dma_debug_init(u32 num_entries)
@@ -153,6 +155,10 @@
 static inline void debug_dma_sync_sg_for_device(struct device *dev,
 						struct scatterlist *sg,
 						int nelems, int direction)
+{
+}
+
+static inline void debug_dma_dump_mappings(struct device *dev)
 {
 }
  
@@ -194,6 +194,36 @@
 }
  
 /*
+ * 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 D=%Lx L=%Lx %s\n",
+					 type2name[entry->type], idx,
+					 (unsigned long long)entry->paddr,
+					 entry->dev_addr, entry->size,
+					 dir2name[entry->direction]);
+			}
+		}
+
+		spin_unlock_irqrestore(&bucket->lock, flags);
+	}
+}
+EXPORT_SYMBOL(debug_dma_dump_mappings);
+
+/*
  * Wrapper function for adding an entry to the hash.
  * This function takes care of locking itself.
  */
...	...	@@ -76,6 +76,8 @@
76	76	struct scatterlist *sg,
77	77	int nelems, int direction);
78	78
	79	+extern void debug_dma_dump_mappings(struct device *dev);
	80	+
79	81	#else /* CONFIG_DMA_API_DEBUG */
80	82
81	83	static inline void dma_debug_init(u32 num_entries)
...	...	@@ -153,6 +155,10 @@
153	155	static inline void debug_dma_sync_sg_for_device(struct device *dev,
154	156	struct scatterlist *sg,
155	157	int nelems, int direction)
	158	+{
	159	+}
	160	+
	161	+static inline void debug_dma_dump_mappings(struct device *dev)
156	162	{
157	163	}
158	164
...	...	@@ -194,6 +194,36 @@
194	194	}
195	195
196	196	/*
	197	+ * Dump mapping entries for debugging purposes
	198	+ */
	199	+void debug_dma_dump_mappings(struct device *dev)
	200	+{
	201	+ int idx;
	202	+
	203	+ for (idx = 0; idx < HASH_SIZE; idx++) {
	204	+ struct hash_bucket *bucket = &dma_entry_hash[idx];
	205	+ struct dma_debug_entry *entry;
	206	+ unsigned long flags;
	207	+
	208	+ spin_lock_irqsave(&bucket->lock, flags);
	209	+
	210	+ list_for_each_entry(entry, &bucket->list, list) {
	211	+ if (!dev \|\| dev == entry->dev) {
	212	+ dev_info(entry->dev,
	213	+ "%s idx %d P=%Lx D=%Lx L=%Lx %s\n",
	214	+ type2name[entry->type], idx,
	215	+ (unsigned long long)entry->paddr,
	216	+ entry->dev_addr, entry->size,
	217	+ dir2name[entry->direction]);
	218	+ }
	219	+ }
	220	+
	221	+ spin_unlock_irqrestore(&bucket->lock, flags);
	222	+ }
	223	+}
	224	+EXPORT_SYMBOL(debug_dma_dump_mappings);
	225	+
	226	+/*
197	227	* Wrapper function for adding an entry to the hash.
198	228	* This function takes care of locking itself.
199	229	*/