4 files changed, 26 insertions, 3 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 */
diff --git a/include/asm-s390/sparsemem.h b/include/asm-s390/sparsemem.h
index 06dfdab6c0e8..545d219e6a2d 100644
--- a/include/asm-s390/sparsemem.h
+++ b/include/asm-s390/sparsemem.h
@@ -1,15 +1,15 @@
 #ifndef _ASM_S390_SPARSEMEM_H
 #define _ASM_S390_SPARSEMEM_H
 
-#define SECTION_SIZE_BITS       25
-
 #ifdef CONFIG_64BIT
 
+#define SECTION_SIZE_BITS       28
 #define MAX_PHYSADDR_BITS       42
 #define MAX_PHYSMEM_BITS        42
 
 #else
 
+#define SECTION_SIZE_BITS       25
 #define MAX_PHYSADDR_BITS       31
 #define MAX_PHYSMEM_BITS        31
 
diff --git a/mm/Kconfig b/mm/Kconfig
index 3aa819d628c1..4242743b981b 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -129,7 +129,7 @@ config MEMORY_HOTPLUG
         bool "Allow for memory hot-add"
         depends on SPARSEMEM || X86_64_ACPI_NUMA
         depends on HOTPLUG && !HIBERNATION && ARCH_ENABLE_MEMORY_HOTPLUG
-        depends on (IA64 || X86 || PPC64 || SUPERH)
+        depends on (IA64 || X86 || PPC64 || SUPERH || S390)
 
 comment "Memory hotplug is currently incompatible with Software Suspend"
         depends on SPARSEMEM && HOTPLUG && HIBERNATION