[PATCH 2/2] lib/test_bits.c: Add tests for GENMASK_U128()

[Anshuman Khandual <anshuman.khandual@xxxxxxx>]

This adds GENMASK_U128() tests although currently only 64 bit wide masks
are being tested.

Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
---
 lib/test_bits.c | 21 +++++++++++++++++++++
 1 file changed, 21 insertions(+)

diff --git a/lib/test_bits.c b/lib/test_bits.c
index 01313980f175..2515ddc34409 100644
--- a/lib/test_bits.c
+++ b/lib/test_bits.c
@@ -39,6 +39,24 @@ static void genmask_ull_test(struct kunit *test)
 #endif
 }
 
+static void genmask_u128_test(struct kunit *test)
+{
+	/* Tests mask generation only when the mask width is within 64 bits */
+	KUNIT_EXPECT_EQ(test, 0x0000000000ff0000ULL, GENMASK_U128(87, 80) >> 64);
+	KUNIT_EXPECT_EQ(test, 0x0000000000ffffffULL, GENMASK_U128(87, 64) >> 64);
+	KUNIT_EXPECT_EQ(test, 0x0000000000000001ULL, GENMASK_U128(0, 0));
+	KUNIT_EXPECT_EQ(test, 0xffffffffffffffffULL, GENMASK_U128(63, 0));
+	KUNIT_EXPECT_EQ(test, 0xffffffffffffffffULL, GENMASK_U128(64, 0) >> 1);
+	KUNIT_EXPECT_EQ(test, 0x00000000ffffffffULL, GENMASK_U128(81, 50) >> 50);
+
+#ifdef TEST_GENMASK_FAILURES
+	/* these should fail compilation */
+	GENMASK_U128(0, 1);
+	GENMASK_U128(0, 10);
+	GENMASK_U128(9, 10);
+#endif
+}
+
 static void genmask_input_check_test(struct kunit *test)
 {
 	unsigned int x, y;
@@ -56,12 +74,15 @@ static void genmask_input_check_test(struct kunit *test)
 	/* Valid input */
 	KUNIT_EXPECT_EQ(test, 0, GENMASK_INPUT_CHECK(1, 1));
 	KUNIT_EXPECT_EQ(test, 0, GENMASK_INPUT_CHECK(39, 21));
+	KUNIT_EXPECT_EQ(test, 0, GENMASK_INPUT_CHECK(100, 80));
+	KUNIT_EXPECT_EQ(test, 0, GENMASK_INPUT_CHECK(110, 65));
 }
 
 
 static struct kunit_case bits_test_cases[] = {
 	KUNIT_CASE(genmask_test),
 	KUNIT_CASE(genmask_ull_test),
+	KUNIT_CASE(genmask_u128_test),
 	KUNIT_CASE(genmask_input_check_test),
 	{}
 };
-- 
2.30.2