--- orig/arch/ppc/mm/init.c
+++ mod/arch/ppc/mm/init.c
@@ -388,6 +388,10 @@
 	free_area_init(zones_size);
 }
 
+#ifdef CONFIG_HIGHMEM
+unsigned long highstart_pfn;
+#endif
+
 void __init mem_init(void)
 {
 	unsigned long addr;
@@ -395,10 +399,9 @@
 	int datapages = 0;
 	int initpages = 0;
 #ifdef CONFIG_HIGHMEM
-	unsigned long highmem_mapnr;
 
-	highmem_mapnr = total_lowmem >> PAGE_SHIFT;
-	highmem_start_page = mem_map + highmem_mapnr;
+	highstart_pfn = total_lowmem >> PAGE_SHIFT;
+	highmem_start_page = mem_map + highstart_pfn;
 #endif /* CONFIG_HIGHMEM */
 	max_mapnr = total_memory >> PAGE_SHIFT;
 
@@ -451,7 +454,7 @@
 	{
 		unsigned long pfn;
 
-		for (pfn = highmem_mapnr; pfn < max_mapnr; ++pfn) {
+		for (pfn = highstart_pfn; pfn < max_mapnr; ++pfn) {
 			struct page *page = mem_map + pfn;
 
 			ClearPageReserved(page);