x86: provide a bad_dma_address symbol for i386

It's initially 0, since we don't expect any DMA there.

Signed-off-by: Glauber Costa <gcosta@redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>

3 files changed, 6 insertions, 1 deletions

diff --git a/arch/x86/kernel/pci-dma_32.c b/arch/x86/kernel/pci-dma_32.c
index 453b4bda271..55ab3c874d8 100644
--- a/arch/x86/kernel/pci-dma_32.c
+++ b/arch/x86/kernel/pci-dma_32.c
@@ -14,6 +14,10 @@
 #include <linux/module.h>
 #include <asm/io.h>
 
+/* For i386, we make it point to the NULL address */
+dma_addr_t bad_dma_address __read_mostly = 0x0;
+EXPORT_SYMBOL(bad_dma_address);
+
 struct dma_coherent_mem {
         void            *virt_base;
         u32             device_base;
diff --git a/include/asm-x86/dma-mapping.h b/include/asm-x86/dma-mapping.h
index c671a0aea59..984935d86bb 100644
--- a/include/asm-x86/dma-mapping.h
+++ b/include/asm-x86/dma-mapping.h
@@ -10,6 +10,8 @@
 #include <asm/io.h>
 #include <asm/swiotlb.h>
 
+extern dma_addr_t bad_dma_address;
+
 struct dma_mapping_ops {
         int             (*mapping_error)(dma_addr_t dma_addr);
         void*           (*alloc_coherent)(struct device *dev, size_t size,
diff --git a/include/asm-x86/dma-mapping_64.h b/include/asm-x86/dma-mapping_64.h
index 9674dac9fa3..352bf4164a5 100644
--- a/include/asm-x86/dma-mapping_64.h
+++ b/include/asm-x86/dma-mapping_64.h
@@ -1,7 +1,6 @@
 #ifndef _X8664_DMA_MAPPING_H
 #define _X8664_DMA_MAPPING_H 1
 
-extern dma_addr_t bad_dma_address;
 extern int iommu_merge;
 
 static inline int dma_mapping_error(dma_addr_t dma_addr)