kselftest: Add exit code defines

Define the exit codes with KSFT_PASS and similar so tests can use these
directly if they choose. Also enable harnesses and other tooling to use
the defines instead of hardcoding the return codes.

Cc: Shuah Khan <shuahkh@osg.samsung.com>
Cc: linux-api@vger.kernel.org
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Davidlohr Bueso <dave@stgolabs.net>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Darren Hart <dvhart@linux.intel.com>
Signed-off-by: Shuah Khan <shuahkh@osg.samsung.com>
diff --git a/tools/testing/selftests/kselftest.h b/tools/testing/selftests/kselftest.h
index 572c888..ef1c80d 100644
--- a/tools/testing/selftests/kselftest.h
+++ b/tools/testing/selftests/kselftest.h
@@ -13,6 +13,13 @@
 #include <stdlib.h>
 #include <unistd.h>
 
+/* define kselftest exit codes */
+#define KSFT_PASS  0
+#define KSFT_FAIL  1
+#define KSFT_XFAIL 2
+#define KSFT_XPASS 3
+#define KSFT_SKIP  4
+
 /* counters */
 struct ksft_count {
 	unsigned int ksft_pass;
@@ -40,23 +47,23 @@
 
 static inline int ksft_exit_pass(void)
 {
-	exit(0);
+	exit(KSFT_PASS);
 }
 static inline int ksft_exit_fail(void)
 {
-	exit(1);
+	exit(KSFT_FAIL);
 }
 static inline int ksft_exit_xfail(void)
 {
-	exit(2);
+	exit(KSFT_XFAIL);
 }
 static inline int ksft_exit_xpass(void)
 {
-	exit(3);
+	exit(KSFT_XPASS);
 }
 static inline int ksft_exit_skip(void)
 {
-	exit(4);
+	exit(KSFT_SKIP);
 }
 
 #endif /* __KSELFTEST_H */