[IA64] Simple memory hot-add for ia64.

First step to memory hotplug for ia64 (add only,
all new memory is added to node 0, does not use
ZONE_EASY_RECLAIM yet).
Signed-off-by: Yasunori Goto <y-goto@jp.fujitsu.com>
Signed-off-by: Tony Luck <tony.luck@intel.com>

arch/ia64/mm/init.c

@@ -635,3 +635,39 @@ mem_init (void)
 	ia32_mem_init();
 #endif
 }
+
+#ifdef CONFIG_MEMORY_HOTPLUG
+void online_page(struct page *page)
+{
+	ClearPageReserved(page);
+	set_page_count(page, 1);
+	__free_page(page);
+	totalram_pages++;
+	num_physpages++;
+}
+
+int add_memory(u64 start, u64 size)
+{
+	pg_data_t *pgdat;
+	struct zone *zone;
+	unsigned long start_pfn = start >> PAGE_SHIFT;
+	unsigned long nr_pages = size >> PAGE_SHIFT;
+	int ret;
+
+	pgdat = NODE_DATA(0);
+
+	zone = pgdat->node_zones + ZONE_NORMAL;
+	ret = __add_pages(zone, start_pfn, nr_pages);
+
+	if (ret)
+		printk("%s: Problem encountered in __add_pages() as ret=%d\n",
+		       __FUNCTION__,  ret);
+
+	return ret;
+}
+
+int remove_memory(u64 start, u64 size)
+{
+	return -EINVAL;
+}
+#endif