diff --git a/drivers/base/memory.c b/drivers/base/memory.c
index af9c911cd6b5..ab5c9a7dfeca 100644
--- a/drivers/base/memory.c
+++ b/drivers/base/memory.c
@@ -228,7 +228,7 @@ memory_block_action(unsigned long phys_index, unsigned long action, int online_t
 	struct page *first_page;
 	int ret;
 
-	start_pfn = phys_index << PFN_SECTION_SHIFT;
+	start_pfn = section_nr_to_pfn(phys_index);
 	first_page = pfn_to_page(start_pfn);
 
 	switch (action) {
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 65842d688b7c..aaec7758eec3 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -502,7 +502,7 @@ int __ref __add_pages(int nid, struct zone *zone, unsigned long phys_start_pfn,
 	end_sec = pfn_to_section_nr(phys_start_pfn + nr_pages - 1);
 
 	for (i = start_sec; i <= end_sec; i++) {
-		err = __add_section(nid, zone, i << PFN_SECTION_SHIFT);
+		err = __add_section(nid, zone, section_nr_to_pfn(i));
 
 		/*
 		 * EEXIST is finally dealt with by ioresource collision