1 files changed, 66 insertions, 0 deletions
diff --git a/tools/testing/selftests/vDSO/vdso_test_gettimeofday.c b/tools/testing/selftests/vDSO/vdso_test_gettimeofday.c
new file mode 100644
index 000000000000..8ccc73ed8240
--- /dev/null
+++ b/tools/testing/selftests/vDSO/vdso_test_gettimeofday.c
@@ -0,0 +1,66 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * vdso_test_gettimeofday.c: Sample code to test parse_vdso.c and
+ *                           vDSO gettimeofday()
+ * Copyright (c) 2014 Andy Lutomirski
+ *
+ * Compile with:
+ * gcc -std=gnu99 vdso_test_gettimeofday.c parse_vdso_gettimeofday.c
+ *
+ * Tested on x86, 32-bit and 64-bit.  It may work on other architectures, too.
+ */
+
+#include <stdint.h>
+#include <elf.h>
+#include <stdio.h>
+#include <sys/auxv.h>
+#include <sys/time.h>
+
+#include "../kselftest.h"
+#include "parse_vdso.h"
+
+/*
+ * ARM64's vDSO exports its gettimeofday() implementation with a different
+ * name and version from other architectures, so we need to handle it as
+ * a special case.
+ */
+#if defined(__aarch64__)
+const char *version = "LINUX_2.6.39";
+const char *name = "__kernel_gettimeofday";
+#else
+const char *version = "LINUX_2.6";
+const char *name = "__vdso_gettimeofday";
+#endif
+
+int main(int argc, char **argv)
+{
+	unsigned long sysinfo_ehdr = getauxval(AT_SYSINFO_EHDR);
+	if (!sysinfo_ehdr) {
+		printf("AT_SYSINFO_EHDR is not present!\n");
+		return KSFT_SKIP;
+	}
+
+	vdso_init_from_sysinfo_ehdr(getauxval(AT_SYSINFO_EHDR));
+
+	/* Find gettimeofday. */
+	typedef long (*gtod_t)(struct timeval *tv, struct timezone *tz);
+	gtod_t gtod = (gtod_t)vdso_sym(version, name);
+
+	if (!gtod) {
+		printf("Could not find %s\n", name);
+		return KSFT_SKIP;
+	}
+
+	struct timeval tv;
+	long ret = gtod(&tv, 0);
+
+	if (ret == 0) {
+		printf("The time is %lld.%06lld\n",
+		       (long long)tv.tv_sec, (long long)tv.tv_usec);
+	} else {
+		printf("%s failed\n", name);
+		return KSFT_FAIL;
+	}
+
+	return 0;
+}