Keeping 'struct timespec' and 'struct __kernel_timespec' compatible
allows the source code to stay simple.

Validate that the types stay compatible.

Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
---
 tools/testing/selftests/nolibc/nolibc-test.c | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)

diff --git a/tools/testing/selftests/nolibc/nolibc-test.c b/tools/testing/selftests/nolibc/nolibc-test.c
index 3c5a226dad3a..3446d76a984e 100644
--- a/tools/testing/selftests/nolibc/nolibc-test.c
+++ b/tools/testing/selftests/nolibc/nolibc-test.c
@@ -1428,6 +1428,32 @@ int test_difftime(void)
 	return 0;
 }
 
+int test_time_types(void)
+{
+	struct __kernel_timespec kts;
+	struct timespec ts;
+
+	if (!__builtin_types_compatible_p(time_t, __kernel_time64_t))
+		return 1;
+
+	if (sizeof(ts) != sizeof(kts))
+		return 1;
+
+	if (!__builtin_types_compatible_p(__typeof__(ts.tv_sec), __typeof__(kts.tv_sec)))
+		return 1;
+
+	if (!__builtin_types_compatible_p(__typeof__(ts.tv_nsec), __typeof__(kts.tv_nsec)))
+		return 1;
+
+	if (offsetof(__typeof__(ts), tv_sec) != offsetof(__typeof__(kts), tv_sec))
+		return 1;
+
+	if (offsetof(__typeof__(ts), tv_nsec) != offsetof(__typeof__(kts), tv_nsec))
+		return 1;
+
+	return 0;
+}
+
 int run_stdlib(int min, int max)
 {
 	int test;
@@ -1553,6 +1579,7 @@ int run_stdlib(int min, int max)
 		CASE_TEST(difftime);                EXPECT_ZR(1, test_difftime()); break;
 		CASE_TEST(memchr_foobar6_o);        EXPECT_STREQ(1, memchr("foobar", 'o', 6), "oobar"); break;
 		CASE_TEST(memchr_foobar3_b);        EXPECT_STRZR(1, memchr("foobar", 'b', 3)); break;
+		CASE_TEST(time_types);              EXPECT_ZR(1, test_time_types()); break;
 
 		case __LINE__:
 			return ret; /* must be last */

-- 
2.52.0