diff --git a/arch/ia64/kernel/ia64_ksyms.c b/arch/ia64/kernel/ia64_ksyms.c
index 0157281..5db9d3b 100644
--- a/arch/ia64/kernel/ia64_ksyms.c
+++ b/arch/ia64/kernel/ia64_ksyms.c
@@ -42,6 +42,7 @@
 
 #ifdef CONFIG_VIRTUAL_MEM_MAP
 #include <linux/bootmem.h>
+EXPORT_SYMBOL(min_low_pfn);	/* defined by bootmem.c, but not exported by generic code */
 EXPORT_SYMBOL(max_low_pfn);	/* defined by bootmem.c, but not exported by generic code */
 #endif
 
diff --git a/include/asm-ia64/page.h b/include/asm-ia64/page.h
index 9dd9da1..5e6362a 100644
--- a/include/asm-ia64/page.h
+++ b/include/asm-ia64/page.h
@@ -110,8 +110,9 @@
 # define pfn_to_page(pfn)	(mem_map + (pfn))
 #elif defined(CONFIG_DISCONTIGMEM)
 extern struct page *vmem_map;
+extern unsigned long min_low_pfn;
 extern unsigned long max_low_pfn;
-# define pfn_valid(pfn)		(((pfn) < max_low_pfn) && ia64_pfn_valid(pfn))
+# define pfn_valid(pfn)		(((pfn) >= min_low_pfn) && ((pfn) < max_low_pfn) && ia64_pfn_valid(pfn))
 # define page_to_pfn(page)	((unsigned long) (page - vmem_map))
 # define pfn_to_page(pfn)	(vmem_map + (pfn))
 #endif