ARM: SMP: wait for CPU to be marked active
When we bring a CPU online, we should wait for it to become active
before entering the idle thread, so we know that the scheduler and
thread migration is going to work.
Signed-off-by: Russell King <rmk+kernel@arm.linux.org.uk>
diff --git a/arch/arm/kernel/smp.c b/arch/arm/kernel/smp.c
index 344e52b..e7f92a4 100644
--- a/arch/arm/kernel/smp.c
+++ b/arch/arm/kernel/smp.c
@@ -318,9 +318,13 @@
smp_store_cpu_info(cpu);
/*
- * OK, now it's safe to let the boot CPU continue
+ * OK, now it's safe to let the boot CPU continue. Wait for
+ * the CPU migration code to notice that the CPU is online
+ * before we continue.
*/
set_cpu_online(cpu, true);
+ while (!cpu_active(cpu))
+ cpu_relax();
/*
* OK, it's off to the idle thread for us