1 files changed, 65 insertions, 0 deletions
diff --git a/tools/testing/selftests/rseq/legacy_check.c b/tools/testing/selftests/rseq/legacy_check.c
new file mode 100644
index 000000000000..3f7de4e28303
--- /dev/null
+++ b/tools/testing/selftests/rseq/legacy_check.c
@@ -0,0 +1,65 @@
+// SPDX-License-Identifier: GPL-2.0
+#ifndef _GNU_SOURCE
+#define _GNU_SOURCE
+#endif
+
+#include <errno.h>
+#include <signal.h>
+#include <stdint.h>
+#include <unistd.h>
+
+#include "rseq.h"
+
+#include "../kselftest_harness.h"
+
+FIXTURE(legacy)
+{
+};
+
+static int cpu_id_in_sigfn = -1;
+
+static void sigfn(int sig)
+{
+	struct rseq_abi *rs = rseq_get_abi();
+
+	cpu_id_in_sigfn = rs->cpu_id_start;
+}
+
+FIXTURE_SETUP(legacy)
+{
+	int res = __rseq_register_current_thread(true, true);
+
+	switch (res) {
+	case -ENOSYS:
+		SKIP(return, "RSEQ not enabled\n");
+	case -EBUSY:
+		SKIP(return, "GLIBC owns RSEQ. Disable GLIBC RSEQ registration\n");
+	default:
+		ASSERT_EQ(res, 0);
+	}
+
+	ASSERT_NE(signal(SIGUSR1, sigfn), SIG_ERR);
+}
+
+FIXTURE_TEARDOWN(legacy)
+{
+}
+
+TEST_F(legacy, legacy_test)
+{
+	struct rseq_abi *rs = rseq_get_abi();
+
+	ASSERT_NE(rs, NULL);
+
+	/* Overwrite rs::cpu_id_start */
+	rs->cpu_id_start = -1;
+	sleep(1);
+	ASSERT_NE(rs->cpu_id_start, -1);
+
+	rs->cpu_id_start = -1;
+	ASSERT_EQ(raise(SIGUSR1), 0);
+	ASSERT_NE(rs->cpu_id_start, -1);
+	ASSERT_NE(cpu_id_in_sigfn, -1);
+}
+
+TEST_HARNESS_MAIN