Reserve the sys_prctl() numbers for and add the stub for allowing

programs to select whether they use statistical time accounting
or accurate timestamp based accounting.

include/linux/prctl.h

@@ -34,4 +34,14 @@
 # define PR_FP_EXC_ASYNC	2	/* async recoverable exception mode */
 # define PR_FP_EXC_PRECISE	3	/* precise exception mode */
 
+/* Get/set whether we use statistical process timing or accurate timestamp
+ * based process timing */
+#define PR_GET_TIMING   13
+#define PR_SET_TIMING   14
+# define PR_TIMING_STATISTICAL  0       /* Normal, traditional,
+                                                   statistical process timing */
+# define PR_TIMING_TIMESTAMP    1       /* Accurate timestamp based
+                                                   process timing */
+
+
 #endif /* _LINUX_PRCTL_H */

kernel/sys.c

@@ -1399,7 +1399,15 @@ asmlinkage long sys_prctl(int option, unsigned long arg2, unsigned long arg3,
 		case PR_GET_FPEXC:
 			error = GET_FPEXC_CTL(current, arg2);
 			break;
-
+		case PR_GET_TIMING:
+			error = PR_TIMING_STATISTICAL;
+			break;
+		case PR_SET_TIMING:
+			if (arg2 == PR_TIMING_STATISTICAL)
+				error = 0;
+			else
+				error = -EINVAL;
+			break;
 
 		case PR_GET_KEEPCAPS:
 			if (current->keep_capabilities)