2 files changed, 11 insertions, 1 deletions

diff --git a/include/linux/perf_counter.h b/include/linux/perf_counter.h
index a9d823a93fe8..2b36afe6ae0f 100644
--- a/include/linux/perf_counter.h
+++ b/include/linux/perf_counter.h
@@ -694,6 +694,8 @@ struct perf_sample_data {
 
 extern int perf_counter_overflow(struct perf_counter *counter, int nmi,
                                  struct perf_sample_data *data);
+extern void perf_counter_output(struct perf_counter *counter, int nmi,
+                                struct perf_sample_data *data);
 
 /*
  * Return 1 for a software counter, 0 for a hardware counter
diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c
index b0b20a07f394..e26d2fcfa320 100644
--- a/kernel/perf_counter.c
+++ b/kernel/perf_counter.c
@@ -88,6 +88,7 @@ void __weak hw_perf_disable(void)		{ barrier(); }
 void __weak hw_perf_enable(void)                { barrier(); }
 
 void __weak hw_perf_counter_setup(int cpu)      { barrier(); }
+void __weak hw_perf_counter_setup_online(int cpu)       { barrier(); }
 
 int __weak
 hw_perf_group_sched_in(struct perf_counter *group_leader,
@@ -2630,7 +2631,7 @@ static u32 perf_counter_tid(struct perf_counter *counter, struct task_struct *p)
         return task_pid_nr_ns(p, counter->ns);
 }
 
-static void perf_counter_output(struct perf_counter *counter, int nmi,
+void perf_counter_output(struct perf_counter *counter, int nmi,
                                 struct perf_sample_data *data)
 {
         int ret;
@@ -4592,6 +4593,11 @@ perf_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu)
                 perf_counter_init_cpu(cpu);
                 break;
 
+        case CPU_ONLINE:
+        case CPU_ONLINE_FROZEN:
+                hw_perf_counter_setup_online(cpu);
+                break;
+
         case CPU_DOWN_PREPARE:
         case CPU_DOWN_PREPARE_FROZEN:
                 perf_counter_exit_cpu(cpu);
@@ -4616,6 +4622,8 @@ void __init perf_counter_init(void)
 {
         perf_cpu_notify(&perf_cpu_nb, (unsigned long)CPU_UP_PREPARE,
                         (void *)(long)smp_processor_id());
+        perf_cpu_notify(&perf_cpu_nb, (unsigned long)CPU_ONLINE,
+                        (void *)(long)smp_processor_id());
         register_cpu_notifier(&perf_cpu_nb);
 }