From: Heiko Carstens <heiko.carstens@de.ibm.com>
Date: Thu, 29 Oct 2009 14:04:13 +0000 (+0100)
Subject: [S390] smp: fix sigp stop handling
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=f8501ba77d69c88a65e4ebbe03bdc65b1edb0b86;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git

[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>
---

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: