Re: [PATCH 07/10] x86: add checks for alloc/free_coherent code

Impact: detect bugs in alloc/free_coherent usage

Signed-off-by: Joerg Roedel <redacted>
---
 arch/x86/include/asm/dma-mapping.h |   10 +++++-
 arch/x86/include/asm/dma_debug.h   |   20 +++++++++++++
 arch/x86/kernel/pci-dma-debug.c    |   56 ++++++++++++++++++++++++++++++++++++
 3 files changed, 84 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/dma-mapping.h b/arch/x86/include/asm/dma-mapping.h
index c7bdb75..2893adb 100644
--- a/arch/x86/include/asm/dma-mapping.h
+++ b/arch/x86/include/asm/dma-mapping.h

@@ -304,8 +304,12 @@ dma_alloc_coherent(struct device *dev, size_t size, dma_addr_t *dma_handle,
 	if (!ops->alloc_coherent)
 		return NULL;
 
-	return ops->alloc_coherent(dev, size, dma_handle,
-				   dma_alloc_coherent_gfp_flags(dev, gfp));
+	memory = ops->alloc_coherent(dev, size, dma_handle,
+				     dma_alloc_coherent_gfp_flags(dev, gfp));
+
+	debug_alloc_coherent(dev, size, *dma_handle, memory);
+
+	return memory;
 }
 
 static inline void dma_free_coherent(struct device *dev, size_t size,

@@ -320,6 +324,8 @@ static inline void dma_free_coherent(struct device *dev, size_t size,
 
 	if (ops->free_coherent)
 		ops->free_coherent(dev, size, vaddr, bus);
+
+	debug_free_coherent(dev, size, vaddr, bus);
 }
 
 #endif

diff --git a/arch/x86/include/asm/dma_debug.h b/arch/x86/include/asm/dma_debug.h
index ff06d1c..7245e27 100644
--- a/arch/x86/include/asm/dma_debug.h
+++ b/arch/x86/include/asm/dma_debug.h

@@ -59,6 +59,14 @@ extern
 void debug_unmap_sg(struct device *dev, struct scatterlist *sglist,
 		    int nelems, int dir);
 
+extern
+void debug_alloc_coherent(struct device *dev, size_t size,
+			  dma_addr_t dma_addr, void *virt);
+
+extern
+void debug_free_coherent(struct device *dev, size_t size,
+			 void *virt, dma_addr_t addr);
+
 #else /* CONFIG_DMA_API_DEBUG */
 
 static inline

@@ -90,6 +98,18 @@ void debug_unmap_sg(struct device *dev, struct scatterlist *sglist,
 {
 }
 
+static inline
+void debug_alloc_coherent(struct device *dev, size_t size,
+			  dma_addr_t dma_addr, void *virt)
+{
+}
+
+static inline
+void debug_free_coherent(struct device *dev, size_t size,
+			 void *virt, dma_addr_t addr)
+{
+}
+
 #endif /* CONFIG_DMA_API_DEBUG */
 
 #endif /* __ASM_X86_DMA_DEBUG */

diff --git a/arch/x86/kernel/pci-dma-debug.c b/arch/x86/kernel/pci-dma-debug.c
index 55ef69a..db5ef9a 100644
--- a/arch/x86/kernel/pci-dma-debug.c
+++ b/arch/x86/kernel/pci-dma-debug.c

@@ -352,3 +352,59 @@ void debug_unmap_sg(struct device *dev, struct scatterlist *sglist,
 }
 EXPORT_SYMBOL(debug_unmap_sg);
 
+void debug_alloc_coherent(struct device *dev, size_t size,
+			  dma_addr_t dma_addr, void *virt)
+{
+	unsigned long flags;
+	struct dma_debug_entry *entry;
+
+	if (dma_addr == bad_dma_address)
+		return;
+
+	entry = dma_entry_alloc();
+	if (!entry)
+		return;
+
+	entry->type      = DMA_DEBUG_COHERENT;
+	entry->dev       = dev;
+	entry->cpu_addr  = virt;
+	entry->size      = size;
+	entry->dev_addr  = dma_addr;
+	entry->direction = DMA_BIDIRECTIONAL;
+
+	spin_lock_irqsave(&dma_lock, flags);
+	add_dma_entry(entry);
+	spin_unlock_irqrestore(&dma_lock, flags);
+}
+EXPORT_SYMBOL(debug_alloc_coherent);