common: security for performance component

The fix is designed to return an error in the case of event duplication.

CVE: CVE-2016-3768
Bug: 28172137

Change-Id: I482382d0623a06e302a15756f4fa3838cd1c9c36
Reviewed-on: http://mcrd1-22-pc.corpnet.asus/code-review/master/237863


Tested-by: Yu-Hao Lin <yu-hao_lin@asus.com>
Reviewed-by: Yu-Hao Lin <yu-hao_lin@asus.com>
Reviewed-by: Eric1 Lin <Eric1_Lin@asus.com>

arch/arm/kernel/perf_event.c

@@ -240,6 +240,7 @@ armpmu_add(struct perf_event *event, int flags)
 			pr_err("Event: %llx failed constraint check.\n",
 					event->attr.config);
 			event->state = PERF_EVENT_STATE_OFF;
+			err = -EPERM;
 			goto out;
 		}
 

arch/arm/mach-msm/perf_event_msm_krait_l2.c

@@ -473,6 +473,7 @@ static int msm_l2_test_set_ev_constraint(struct perf_event *event)
 			if (!(event->cpu < 0)) {
 				event->state = PERF_EVENT_STATE_OFF;
 				event->attr.constraint_duplicate = 1;
+				err = -EPERM;
 			}
 	}
 out: