[PATCH v5 6/7] test_bits: add tests for GENMASK_U*()

Vincent Mailhol via B4 Relay
2025-03-06T11:31:07Z

From: Lucas De Marchi <lucas.demarchi@intel.com>

Add some additional tests in lib/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>
---
Changelog:

v4 -> v5:

- Revert v4 change. GENMASK_U8()/GENMASK_U16() are now back to
u8/u16.

v3 -> v4:

- Adjust the type of GENMASK_U8()/GENMASK_U16() from u8/u16 to
unsigned int.

- Reorder the tests to match the order in which the macros are
declared in bits.h.
---
lib/test_bits.c | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)

diff --git a/lib/test_bits.c b/lib/test_bits.c
index dc93ded9fdb201e0d44b3c1cd71e233fd62258a5..91968227687bb11b7d1361b153c27eb851c6c1c2 100644
--- a/lib/test_bits.c
+++ b/lib/test_bits.c
@@ -5,7 +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)
{
@@ -30,11 +39,21 @@ 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

--
2.45.3