selftests/membarrier: Test MEMBARRIER_CMD_GET_REGISTRATIONS

Keep track of previously issued registrations and compare the result
with MEMBARRIER_CMD_GET_REGISTRATIONS return value.
Signed-off-by: Michal Clapinski <mclapinski@google.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Acked-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: Paul E. McKenney <paulmck@kernel.org>
Link: https://lore.kernel.org/r/20221207164338.1535591-3-mclapinski@google.com

tools/testing/selftests/membarrier/membarrier_test_impl.h

@@ -9,11 +9,38 @@
 
 #include "../kselftest.h"
 
+static int registrations;
+
 static int sys_membarrier(int cmd, int flags)
 {
 	return syscall(__NR_membarrier, cmd, flags);
 }
 
+static int test_membarrier_get_registrations(int cmd)
+{
+	int ret, flags = 0;
+	const char *test_name =
+		"sys membarrier MEMBARRIER_CMD_GET_REGISTRATIONS";
+
+	registrations |= cmd;
+
+	ret = sys_membarrier(MEMBARRIER_CMD_GET_REGISTRATIONS, 0);
+	if (ret < 0) {
+		ksft_exit_fail_msg(
+			"%s test: flags = %d, errno = %d\n",
+			test_name, flags, errno);
+	} else if (ret != registrations) {
+		ksft_exit_fail_msg(
+			"%s test: flags = %d, ret = %d, registrations = %d\n",
+			test_name, flags, ret, registrations);
+	}
+	ksft_test_result_pass(
+		"%s test: flags = %d, ret = %d, registrations = %d\n",
+		test_name, flags, ret, registrations);
+
+	return 0;
+}
+
 static int test_membarrier_cmd_fail(void)
 {
 	int cmd = -1, flags = 0;
@@ -113,6 +140,8 @@ static int test_membarrier_register_private_expedited_success(void)
 	ksft_test_result_pass(
 		"%s test: flags = %d\n",
 		test_name, flags);
+
+	test_membarrier_get_registrations(cmd);
 	return 0;
 }
 
@@ -170,6 +199,8 @@ static int test_membarrier_register_private_expedited_sync_core_success(void)
 	ksft_test_result_pass(
 		"%s test: flags = %d\n",
 		test_name, flags);
+
+	test_membarrier_get_registrations(cmd);
 	return 0;
 }
 
@@ -204,6 +235,8 @@ static int test_membarrier_register_global_expedited_success(void)
 	ksft_test_result_pass(
 		"%s test: flags = %d\n",
 		test_name, flags);
+
+	test_membarrier_get_registrations(cmd);
 	return 0;
 }
 

tools/testing/selftests/membarrier/membarrier_test_multi_thread.c

@@ -62,7 +62,7 @@ static int test_mt_membarrier(void)
 int main(int argc, char **argv)
 {
 	ksft_print_header();
-	ksft_set_plan(13);
+	ksft_set_plan(16);
 
 	test_membarrier_query();
 

tools/testing/selftests/membarrier/membarrier_test_single_thread.c

@@ -12,7 +12,9 @@
 int main(int argc, char **argv)
 {
 	ksft_print_header();
-	ksft_set_plan(13);
+	ksft_set_plan(18);
+
+	test_membarrier_get_registrations(/*cmd=*/0);
 
 	test_membarrier_query();
 
@@ -20,5 +22,7 @@ int main(int argc, char **argv)
 
 	test_membarrier_success();
 
+	test_membarrier_get_registrations(/*cmd=*/0);
+
 	return ksft_exit_pass();
 }