[S390] smp: fix sigp stop handling

According to the architecture a cpu must not necessarily enter stopped
state after completion of a sigp instruction with "stop" order code.
So remove the BUG() statement after self sending sigp stop to avoid
that it ever gets reached.
Also add a sigp busy check to make sure that the order gets delivered.

Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/arch/s390/kernel/smp.c b/arch/s390/kernel/smp.c
index c699ac538c49..c99c45b848e3 100644
--- a/arch/s390/kernel/smp.c
+++ b/arch/s390/kernel/smp.c
@@ -647,8 +647,8 @@ void __cpu_die(unsigned int cpu)
 void cpu_die(void)
 {
         idle_task_exit();
-        signal_processor(smp_processor_id(), sigp_stop);
-        BUG();
+        while (signal_processor(smp_processor_id(), sigp_stop) == sigp_busy)
+                cpu_relax();
         for (;;);
 }