test_bits: add tests for GENMASK_U*()

Add some additional tests in lib/tests/test_bits.c to cover the
expected/non-expected values of the fixed-type GENMASK_U*() macros.

Also check that the result value matches the expected type. Since
those are known at build time, use static_assert() instead of normal
kunit tests.

Signed-off-by: Lucas De Marchi <lucas.demarchi@intel.com>
Signed-off-by: Vincent Mailhol <mailhol.vincent@wanadoo.fr>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Yury Norov <yury.norov@gmail.com>

Author: lucasdemarchi

lib/tests/test_bits.c

@@ -5,6 +5,16 @@
 
 #include <kunit/test.h>
 #include <linux/bits.h>
+#include <linux/types.h>
+
+#define assert_type(t, x) _Generic(x, t: x, default: 0)
+
+static_assert(assert_type(unsigned long, GENMASK(31, 0)) == U32_MAX);
+static_assert(assert_type(unsigned long long, GENMASK_ULL(63, 0)) == U64_MAX);
+static_assert(assert_type(u8, GENMASK_U8(7, 0)) == U8_MAX);
+static_assert(assert_type(u16, GENMASK_U16(15, 0)) == U16_MAX);
+static_assert(assert_type(u32, GENMASK_U32(31, 0)) == U32_MAX);
+static_assert(assert_type(u64, GENMASK_U64(63, 0)) == U64_MAX);
 
 
 static void genmask_test(struct kunit *test)
@@ -14,11 +24,21 @@ static void genmask_test(struct kunit *test)
 	KUNIT_EXPECT_EQ(test, 6ul, GENMASK(2, 1));
 	KUNIT_EXPECT_EQ(test, 0xFFFFFFFFul, GENMASK(31, 0));
 
+	KUNIT_EXPECT_EQ(test, 1u, GENMASK_U8(0, 0));
+	KUNIT_EXPECT_EQ(test, 3u, GENMASK_U16(1, 0));
+	KUNIT_EXPECT_EQ(test, 0x10000, GENMASK_U32(16, 16));
+
 #ifdef TEST_GENMASK_FAILURES
 	/* these should fail compilation */
 	GENMASK(0, 1);
 	GENMASK(0, 10);
 	GENMASK(9, 10);
+
+	GENMASK_U32(0, 31);
+	GENMASK_U64(64, 0);
+	GENMASK_U32(32, 0);
+	GENMASK_U16(16, 0);
+	GENMASK_U8(8, 0);
 #endif