ftrace: fix modular build

fix:

 ERROR: "start_critical_timings" [drivers/acpi/processor.ko] undefined!
 ERROR: "stop_critical_timings" [drivers/acpi/processor.ko] undefined!

Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 2 insertions, 0 deletions

diff --git a/kernel/trace/trace_irqsoff.c b/kernel/trace/trace_irqsoff.c
index b1e4a89b08eb..ece6cfb649fa 100644
--- a/kernel/trace/trace_irqsoff.c
+++ b/kernel/trace/trace_irqsoff.c
@@ -253,12 +253,14 @@ void start_critical_timings(void)
         if (preempt_trace() || irq_trace())
                 start_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
 }
+EXPORT_SYMBOL_GPL(start_critical_timings);
 
 void stop_critical_timings(void)
 {
         if (preempt_trace() || irq_trace())
                 stop_critical_timing(CALLER_ADDR0, CALLER_ADDR1);
 }
+EXPORT_SYMBOL_GPL(stop_critical_timings);
 
 #ifdef CONFIG_IRQSOFF_TRACER
 #ifdef CONFIG_PROVE_LOCKING