perf counters: add prctl interface to disable/enable counters

Add a way for self-monitoring tasks to disable/enable counters summarily,
via a prctl:

	PR_TASK_PERF_COUNTERS_DISABLE		31
	PR_TASK_PERF_COUNTERS_ENABLE		32

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

1 files changed, 7 insertions, 0 deletions

diff --git a/kernel/sys.c b/kernel/sys.c
index 31deba8f7d1..0f66633be31 100644
--- a/kernel/sys.c
+++ b/kernel/sys.c
@@ -14,6 +14,7 @@
 #include <linux/prctl.h>
 #include <linux/highuid.h>
 #include <linux/fs.h>
+#include <linux/perf_counter.h>
 #include <linux/resource.h>
 #include <linux/kernel.h>
 #include <linux/kexec.h>
@@ -1716,6 +1717,12 @@ asmlinkage long sys_prctl(int option, unsigned long arg2, unsigned long arg3,
                 case PR_SET_TSC:
                         error = SET_TSC_CTL(arg2);
                         break;
+                case PR_TASK_PERF_COUNTERS_DISABLE:
+                        error = perf_counter_task_disable();
+                        break;
+                case PR_TASK_PERF_COUNTERS_ENABLE:
+                        error = perf_counter_task_enable();
+                        break;
                 case PR_GET_TIMERSLACK:
                         error = current->timer_slack_ns;
                         break;