diff --git a/include/asm-x86/mmzone_32.h b/include/asm-x86/mmzone_32.h
index 118e9812778f..5d6f4ce6e6d6 100644
--- a/include/asm-x86/mmzone_32.h
+++ b/include/asm-x86/mmzone_32.h
@@ -87,9 +87,6 @@ static inline int pfn_to_nid(unsigned long pfn)
 	__pgdat->node_start_pfn + __pgdat->node_spanned_pages;		\
 })
 
-/* XXX: FIXME -- wli */
-#define kern_addr_valid(kaddr)	(0)
-
 #ifdef CONFIG_X86_NUMAQ            /* we have contiguous memory on NUMA-Q */
 #define pfn_valid(pfn)          ((pfn) < num_physpages)
 #else
diff --git a/include/asm-x86/pgtable_32.h b/include/asm-x86/pgtable_32.h
index ed3e70d8d04b..a8be1ee15a99 100644
--- a/include/asm-x86/pgtable_32.h
+++ b/include/asm-x86/pgtable_32.h
@@ -497,9 +497,15 @@ static inline void paravirt_pagetable_setup_done(pgd_t *base)
 
 #endif /* !__ASSEMBLY__ */
 
+/*
+ * kern_addr_valid() is (1) for FLATMEM and (0) for
+ * SPARSEMEM and DISCONTIGMEM
+ */
 #ifdef CONFIG_FLATMEM
 #define kern_addr_valid(addr)	(1)
-#endif /* CONFIG_FLATMEM */
+#else
+#define kern_addr_valid(kaddr)	(0)
+#endif
 
 #define io_remap_pfn_range(vma, vaddr, pfn, size, prot)		\
 		remap_pfn_range(vma, vaddr, pfn, size, prot)
diff --git a/include/asm-x86/sparsemem_32.h b/include/asm-x86/sparsemem_32.h
index cfeed990585f..d89c32100591 100644
--- a/include/asm-x86/sparsemem_32.h
+++ b/include/asm-x86/sparsemem_32.h
@@ -24,8 +24,5 @@
 #define MAX_PHYSMEM_BITS	32
 #endif
 
-/* XXX: FIXME -- wli */
-#define kern_addr_valid(kaddr)  (0)
-
 #endif /* CONFIG_SPARSEMEM */
 #endif /* _I386_SPARSEMEM_H */