[S390] Add support for memory hot-add.

Cc: Gerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

2 files changed, 23 insertions, 0 deletions

diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index 6d0d31651f05..5dc8f8028d52 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -313,6 +313,10 @@ config ARCH_SPARSEMEM_DEFAULT
 config ARCH_SELECT_MEMORY_MODEL
        def_bool y
 
+config ARCH_ENABLE_MEMORY_HOTPLUG
+        def_bool y
+        depends on SPARSEMEM
+
 source "mm/Kconfig"
 
 comment "I/O subsystem configuration"
diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
index 05598649b326..388cc7420055 100644
--- a/arch/s390/mm/init.c
+++ b/arch/s390/mm/init.c
@@ -202,3 +202,22 @@ void free_initrd_mem(unsigned long start, unsigned long end)
         }
 }
 #endif
+
+#ifdef CONFIG_MEMORY_HOTPLUG
+int arch_add_memory(int nid, u64 start, u64 size)
+{
+        struct pglist_data *pgdat;
+        struct zone *zone;
+        int rc;
+
+        pgdat = NODE_DATA(nid);
+        zone = pgdat->node_zones + ZONE_NORMAL;
+        rc = vmem_add_mapping(start, size);
+        if (rc)
+                return rc;
+        rc = __add_pages(zone, PFN_DOWN(start), PFN_DOWN(size));
+        if (rc)
+                vmem_remove_mapping(start, size);
+        return rc;
+}
+#endif /* CONFIG_MEMORY_HOTPLUG */