diff --git a/arch/arm/mm/mm.h b/arch/arm/mm/mm.h
index d5a4e9a..d5a982d 100644
--- a/arch/arm/mm/mm.h
+++ b/arch/arm/mm/mm.h
@@ -81,8 +81,10 @@
 
 #ifdef CONFIG_ZONE_DMA
 extern phys_addr_t arm_dma_limit;
+extern unsigned long arm_dma_pfn_limit;
 #else
 #define arm_dma_limit ((phys_addr_t)~0)
+#define arm_dma_pfn_limit (~0ul >> PAGE_SHIFT)
 #endif
 
 extern phys_addr_t arm_lowmem_limit;