[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>

3 files changed, 6 insertions, 6 deletions

diff --git a/arch/s390/kernel/ipl.c b/arch/s390/kernel/ipl.c
index ee57a42e6e93..4890ac6d7faa 100644
--- a/arch/s390/kernel/ipl.c
+++ b/arch/s390/kernel/ipl.c
@@ -1595,10 +1595,9 @@ static void stop_run(struct shutdown_trigger *trigger)
 {
         if (strcmp(trigger->name, ON_PANIC_STR) == 0)
                 disabled_wait((unsigned long) __builtin_return_address(0));
-        else {
-                signal_processor(smp_processor_id(), sigp_stop);
-                for (;;);
-        }
+        while (signal_processor(smp_processor_id(), sigp_stop) == sigp_busy)
+                cpu_relax();
+        for (;;);
 }
 
 static struct shutdown_action stop_action = {SHUTDOWN_ACTION_STOP_STR,
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 (;;);
 }
 
diff --git a/arch/s390/kernel/swsusp_asm64.S b/arch/s390/kernel/swsusp_asm64.S
index 7c8653e27db6..0f4ef3b856d9 100644
--- a/arch/s390/kernel/swsusp_asm64.S
+++ b/arch/s390/kernel/swsusp_asm64.S
@@ -199,6 +199,7 @@ pgm_check_entry:
         brc     2,4b                    /* busy, try again */
 5:
         sigp    %r9,%r2,__SIGP_STOP     /* stop resume (current) CPU */
+        brc     2,5b                    /* busy, try again */
 6:      j       6b
 
 restart_suspend: