6 files changed, 18 insertions, 12 deletions

diff --git a/arch/s390/kernel/Makefile b/arch/s390/kernel/Makefile
index b3b650a93c7c..4d3e38392cb1 100644
--- a/arch/s390/kernel/Makefile
+++ b/arch/s390/kernel/Makefile
@@ -4,6 +4,11 @@
 
 EXTRA_AFLAGS    := -traditional
 
+#
+# Passing null pointers is ok for smp code, since we access the lowcore here.
+#
+CFLAGS_smp.o    := -Wno-nonnull
+
 obj-y   :=  bitmap.o traps.o time.o process.o base.o early.o \
             setup.o sys_s390.o ptrace.o signal.o cpcmd.o ebcdic.o \
             semaphore.o s390_ext.o debug.o irq.o ipl.o dis.o diag.o
diff --git a/arch/s390/kernel/early.c b/arch/s390/kernel/early.c
index 9f7b73b180f0..01832c440636 100644
--- a/arch/s390/kernel/early.c
+++ b/arch/s390/kernel/early.c
@@ -88,13 +88,17 @@ static noinline __init void create_kernel_nss(void)
 
         __cpcmd(defsys_cmd, NULL, 0, &response);
 
-        if (response != 0)
+        if (response != 0) {
+                kernel_nss_name[0] = '\0';
                 return;
+        }
 
         __cpcmd(savesys_cmd, NULL, 0, &response);
 
-        if (response != strlen(savesys_cmd))
+        if (response != strlen(savesys_cmd)) {
+                kernel_nss_name[0] = '\0';
                 return;
+        }
 
         ipl_flags = IPL_NSS_VALID;
 }
diff --git a/arch/s390/kernel/ipl.c b/arch/s390/kernel/ipl.c
index 60acdc266db1..375232c46c7a 100644
--- a/arch/s390/kernel/ipl.c
+++ b/arch/s390/kernel/ipl.c
@@ -704,6 +704,7 @@ void reipl_run(struct shutdown_trigger *trigger)
         default:
                 break;
         }
+        disabled_wait((unsigned long) __builtin_return_address(0));
 }
 
 static void __init reipl_probe(void)
diff --git a/arch/s390/kernel/process.c b/arch/s390/kernel/process.c
index 1c59ec161cf8..ce203154d8ce 100644
--- a/arch/s390/kernel/process.c
+++ b/arch/s390/kernel/process.c
@@ -152,6 +152,10 @@ static void default_idle(void)
         local_mcck_disable();
         if (test_thread_flag(TIF_MCCK_PENDING)) {
                 local_mcck_enable();
+                /* disable monitor call class 0 */
+                __ctl_clear_bit(8, 15);
+                atomic_notifier_call_chain(&idle_chain, S390_CPU_NOT_IDLE,
+                                           hcpu);
                 local_irq_enable();
                 s390_handle_mcck();
                 return;
diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index 818bd09c0260..8f894d380a62 100644
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -629,14 +629,8 @@ static int __cpuinit smp_alloc_lowcore(int cpu)
         panic_stack = __get_free_page(GFP_KERNEL);
         if (!panic_stack || !async_stack)
                 goto out;
-        /*
-         * Only need to copy the first 512 bytes from address 0. But since
-         * the compiler emits a warning if src == NULL for memcpy use copy_page
-         * instead. Copies more than needed but this code is not performance
-         * critical.
-         */
-        copy_page(lowcore, &S390_lowcore);
-        memset((void *)lowcore + 512, 0, sizeof(*lowcore) - 512);
+        memcpy(lowcore, &S390_lowcore, 512);
+        memset((char *)lowcore + 512, 0, sizeof(*lowcore) - 512);
         lowcore->async_stack = async_stack + ASYNC_SIZE;
         lowcore->panic_stack = panic_stack + PAGE_SIZE;
 
diff --git a/arch/s390/kernel/time.c b/arch/s390/kernel/time.c
index 76a5dd1b4ce9..cb232c155360 100644
--- a/arch/s390/kernel/time.c
+++ b/arch/s390/kernel/time.c
@@ -209,8 +209,6 @@ static void stop_hz_timer(void)
  */
 static void start_hz_timer(void)
 {
-        BUG_ON(!in_interrupt());
-
         if (!cpu_isset(smp_processor_id(), nohz_cpu_mask))
                 return;
         account_ticks(get_clock());