[PATCH v6 2/3] lib: kunit: add tests for __ashldi3(), __ashrdi3(), and __lshrdi3()

Dmitry Antipov
2026-04-25T18:59:08Z

Add KUnit tests for '__ashldi3()', '__ashrdi3()', and '__lshrdi3()'
helper functions used to implement 64-bit arithmetic shift left,
arithmetic shift right and logical shift right, respectively,
on a 32-bit CPUs.

Tested with 'qemu-system-riscv32 -M virt' and 'qemu-system-arm -M virt'.

Reviewed-by: Andy Shevchenko <andriy.shevchenko@intel.com>
Tested-by: Charlie Jenkins <thecharlesjenkins@gmail.com>
Signed-off-by: Dmitry Antipov <dmantipov@yandex.ru>
---
v4 and upwards: bump version to match the series
v3: more tests by Charlie Jenkins
v2: include test-specific headers rather than generic linux/kernel.h
---
lib/Kconfig.debug | 10 +++
lib/tests/Makefile | 1 +
lib/tests/shdi3_kunit.c | 175 ++++++++++++++++++++++++++++++++++++++++
3 files changed, 186 insertions(+)
create mode 100644 lib/tests/shdi3_kunit.c

diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index 8ff5adcfe1e0..ea036ebce64f 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -2971,6 +2971,16 @@ config BITS_TEST

If unsure, say N.

+config SHDI3_KUNIT_TEST
+ tristate "KUnit test for __ashldi3(), __ashrdi3(), and __lshrdi3()"
+ depends on KUNIT
+ depends on (32BIT || ARM)
+ help
+ This builds the unit test for __ashldi3(), __ashrdi3(), and
+ __lshrdi3() helper functions used to implement 64-bit arithmetic
+ shift left, arithmetic shift right and logical shift right,
+ respectively, on a 32-bit CPUs.
+
config SLUB_KUNIT_TEST
tristate "KUnit test for SLUB cache error detection" if !KUNIT_ALL_TESTS
depends on SLUB_DEBUG && KUNIT
diff --git a/lib/tests/Makefile b/lib/tests/Makefile
index 7e9c2fa52e35..4ead57602eac 100644
--- a/lib/tests/Makefile
+++ b/lib/tests/Makefile
@@ -8,6 +8,7 @@ obj-$(CONFIG_BASE64_KUNIT) += base64_kunit.o
obj-$(CONFIG_BITOPS_KUNIT) += bitops_kunit.o
obj-$(CONFIG_BITFIELD_KUNIT) += bitfield_kunit.o
obj-$(CONFIG_BITS_TEST) += test_bits.o
+obj-$(CONFIG_SHDI3_KUNIT_TEST) += shdi3_kunit.o
obj-$(CONFIG_BLACKHOLE_DEV_KUNIT_TEST) += blackhole_dev_kunit.o
obj-$(CONFIG_CHECKSUM_KUNIT) += checksum_kunit.o
obj-$(CONFIG_CMDLINE_KUNIT_TEST) += cmdline_kunit.o
diff --git a/lib/tests/shdi3_kunit.c b/lib/tests/shdi3_kunit.c
new file mode 100644
index 000000000000..44f65e66512b
--- /dev/null
+++ b/lib/tests/shdi3_kunit.c
@@ -0,0 +1,175 @@
+// SPDX-License-Identifier: GPL-2.0-or-later OR Apache-2.0
+/*
+ * Test cases for __ashldi3(), __ashrdi3(), and __lshrdi3().
+ */
+
+#include <linux/array_size.h>
+#include <linux/module.h>
+#include <linux/libgcc.h>
+#include <kunit/test.h>
+
+struct shdi3_test_entry {
+ long long input;
+ int shift;
+ long long result;
+};
+
+static const struct shdi3_test_entry ashldi3_testdata[] = {
+ /* https://github.com/llvm/llvm-project/compiler-rt/test/builtins/Unit/ashldi3_test.c */
+ { 0x0123456789ABCDEFLL, 0, 0x123456789ABCDEFLL },
+ { 0x0123456789ABCDEFLL, 1, 0x2468ACF13579BDELL },
+ { 0x0123456789ABCDEFLL, 2, 0x48D159E26AF37BCLL },
+ { 0x0123456789ABCDEFLL, 3, 0x91A2B3C4D5E6F78LL },
+ { 0x0123456789ABCDEFLL, 4, 0x123456789ABCDEF0LL },
+ { 0x0123456789ABCDEFLL, 28, 0x789ABCDEF0000000LL },
+ { 0x0123456789ABCDEFLL, 29, 0xF13579BDE0000000LL },
+ { 0x0123456789ABCDEFLL, 30, 0xE26AF37BC0000000LL },
+ { 0x0123456789ABCDEFLL, 31, 0xC4D5E6F780000000LL },
+ { 0x0123456789ABCDEFLL, 32, 0x89ABCDEF00000000LL },
+ { 0x0123456789ABCDEFLL, 33, 0x13579BDE00000000LL },
+ { 0x0123456789ABCDEFLL, 34, 0x26AF37BC00000000LL },
+ { 0x0123456789ABCDEFLL, 35, 0x4D5E6F7800000000LL },
+ { 0x0123456789ABCDEFLL, 36, 0x9ABCDEF000000000LL },
+ { 0x0123456789ABCDEFLL, 60, 0xF000000000000000LL },
+ { 0x0123456789ABCDEFLL, 61, 0xE000000000000000LL },
+ { 0x0123456789ABCDEFLL, 62, 0xC000000000000000LL },
+ { 0x0123456789ABCDEFLL, 63, 0x8000000000000000LL },
+};
+
+static void shdi3_test_ashldi3(struct kunit *test)
+{
+ const struct shdi3_test_entry *e;
+ long long ret;
+
+ for (e = ashldi3_testdata;
+ e < ashldi3_testdata + ARRAY_SIZE(ashldi3_testdata); e++) {
+ ret = __ashldi3(e->input, e->shift);
+ KUNIT_EXPECT_EQ_MSG(test, ret, e->result,
+ " when evaluating __ashldi3(%lld, %d)",
+ e->input, e->shift);
+ }
+}
+
+static const struct shdi3_test_entry ashrdi3_testdata[] = {
+ /* https://github.com/llvm/llvm-project/compiler-rt/test/builtins/Unit/ashrdi3_test.c */
+ { 0x0123456789ABCDEFLL, 0, 0x123456789ABCDEFLL },
+ { 0x0123456789ABCDEFLL, 1, 0x91A2B3C4D5E6F7LL },
+ { 0x0123456789ABCDEFLL, 2, 0x48D159E26AF37BLL },
+ { 0x0123456789ABCDEFLL, 3, 0x2468ACF13579BDLL },
+ { 0x0123456789ABCDEFLL, 4, 0x123456789ABCDELL },
+ { 0x0123456789ABCDEFLL, 28, 0x12345678LL },
+ { 0x0123456789ABCDEFLL, 29, 0x91A2B3CLL },
+ { 0x0123456789ABCDEFLL, 30, 0x48D159ELL },
+ { 0x0123456789ABCDEFLL, 31, 0x2468ACFLL },
+ { 0x0123456789ABCDEFLL, 32, 0x1234567LL },
+ { 0x0123456789ABCDEFLL, 33, 0x91A2B3LL },
+ { 0x0123456789ABCDEFLL, 34, 0x48D159LL },
+ { 0x0123456789ABCDEFLL, 35, 0x2468ACLL },
+ { 0x0123456789ABCDEFLL, 36, 0x123456LL },
+ { 0x0123456789ABCDEFLL, 60, 0 },
+ { 0x0123456789ABCDEFLL, 61, 0 },
+ { 0x0123456789ABCDEFLL, 62, 0 },
+ { 0x0123456789ABCDEFLL, 63, 0 },
+ { 0xFEDCBA9876543210LL, 0, 0xFEDCBA9876543210LL },
+ { 0xFEDCBA9876543210LL, 1, 0xFF6E5D4C3B2A1908LL },
+ { 0xFEDCBA9876543210LL, 2, 0xFFB72EA61D950C84LL },
+ { 0xFEDCBA9876543210LL, 3, 0xFFDB97530ECA8642LL },
+ { 0xFEDCBA9876543210LL, 4, 0xFFEDCBA987654321LL },
+ { 0xFEDCBA9876543210LL, 28, 0xFFFFFFFFEDCBA987LL },
+ { 0xFEDCBA9876543210LL, 29, 0xFFFFFFFFF6E5D4C3LL },
+ { 0xFEDCBA9876543210LL, 30, 0xFFFFFFFFFB72EA61LL },
+ { 0xFEDCBA9876543210LL, 31, 0xFFFFFFFFFDB97530LL },
+ { 0xFEDCBA9876543210LL, 32, 0xFFFFFFFFFEDCBA98LL },
+ { 0xFEDCBA9876543210LL, 33, 0xFFFFFFFFFF6E5D4CLL },
+ { 0xFEDCBA9876543210LL, 34, 0xFFFFFFFFFFB72EA6LL },
+ { 0xFEDCBA9876543210LL, 35, 0xFFFFFFFFFFDB9753LL },
+ { 0xFEDCBA9876543210LL, 36, 0xFFFFFFFFFFEDCBA9LL },
+ { 0xAEDCBA9876543210LL, 60, 0xFFFFFFFFFFFFFFFALL },
+ { 0xAEDCBA9876543210LL, 61, 0xFFFFFFFFFFFFFFFDLL },
+ { 0xAEDCBA9876543210LL, 62, 0xFFFFFFFFFFFFFFFELL },
+ { 0xAEDCBA9876543210LL, 63, 0xFFFFFFFFFFFFFFFFLL },
+};
+
+static void shdi3_test_ashrdi3(struct kunit *test)
+{
+ const struct shdi3_test_entry *e;
+ long long ret;
+
+ for (e = ashrdi3_testdata;
+ e < ashrdi3_testdata + ARRAY_SIZE(ashrdi3_testdata); e++) {
+ ret = __ashrdi3(e->input, e->shift);
+ KUNIT_EXPECT_EQ_MSG(test, ret, e->result,
+ " when evaluating __ashrdi3(%lld, %d)",
+ e->input, e->shift);
+ }
+}
+
+static const struct shdi3_test_entry lshrdi3_testdata[] = {
+ /* https://github.com/llvm/llvm-project/compiler-rt/test/builtins/Unit/lshrdi3_test.c */
+ { 0x0123456789ABCDEFLL, 0, 0x123456789ABCDEFLL },
+ { 0x0123456789ABCDEFLL, 1, 0x91A2B3C4D5E6F7LL },
+ { 0x0123456789ABCDEFLL, 2, 0x48D159E26AF37BLL },
+ { 0x0123456789ABCDEFLL, 3, 0x2468ACF13579BDLL },
+ { 0x0123456789ABCDEFLL, 4, 0x123456789ABCDELL },
+ { 0x0123456789ABCDEFLL, 28, 0x12345678LL },
+ { 0x0123456789ABCDEFLL, 29, 0x91A2B3CLL },
+ { 0x0123456789ABCDEFLL, 30, 0x48D159ELL },
+ { 0x0123456789ABCDEFLL, 31, 0x2468ACFLL },
+ { 0x0123456789ABCDEFLL, 32, 0x1234567LL },
+ { 0x0123456789ABCDEFLL, 33, 0x91A2B3LL },
+ { 0x0123456789ABCDEFLL, 34, 0x48D159LL },
+ { 0x0123456789ABCDEFLL, 35, 0x2468ACLL },
+ { 0x0123456789ABCDEFLL, 36, 0x123456LL },
+ { 0x0123456789ABCDEFLL, 60, 0 },
+ { 0x0123456789ABCDEFLL, 61, 0 },
+ { 0x0123456789ABCDEFLL, 62, 0 },
+ { 0x0123456789ABCDEFLL, 63, 0 },
+ { 0xFEDCBA9876543210LL, 0, 0xFEDCBA9876543210LL },
+ { 0xFEDCBA9876543210LL, 1, 0x7F6E5D4C3B2A1908LL },
+ { 0xFEDCBA9876543210LL, 2, 0x3FB72EA61D950C84LL },
+ { 0xFEDCBA9876543210LL, 3, 0x1FDB97530ECA8642LL },
+ { 0xFEDCBA9876543210LL, 4, 0xFEDCBA987654321LL },
+ { 0xFEDCBA9876543210LL, 28, 0xFEDCBA987LL },
+ { 0xFEDCBA9876543210LL, 29, 0x7F6E5D4C3LL },
+ { 0xFEDCBA9876543210LL, 30, 0x3FB72EA61LL },
+ { 0xFEDCBA9876543210LL, 31, 0x1FDB97530LL },
+ { 0xFEDCBA9876543210LL, 32, 0xFEDCBA98LL },
+ { 0xFEDCBA9876543210LL, 33, 0x7F6E5D4CLL },
+ { 0xFEDCBA9876543210LL, 34, 0x3FB72EA6LL },
+ { 0xFEDCBA9876543210LL, 35, 0x1FDB9753LL },
+ { 0xFEDCBA9876543210LL, 36, 0xFEDCBA9LL },
+ { 0xAEDCBA9876543210LL, 60, 0xALL },
+ { 0xAEDCBA9876543210LL, 61, 0x5LL },
+ { 0xAEDCBA9876543210LL, 62, 0x2LL },
+ { 0xAEDCBA9876543210LL, 63, 0x1LL },
+};
+
+static void shdi3_test_lshrdi3(struct kunit *test)
+{
+ const struct shdi3_test_entry *e;
+ long long ret;
+
+ for (e = lshrdi3_testdata;
+ e < lshrdi3_testdata + ARRAY_SIZE(lshrdi3_testdata); e++) {
+ ret = __lshrdi3(e->input, e->shift);
+ KUNIT_EXPECT_EQ_MSG(test, ret, e->result,
+ " when evaluating __lshrdi3(%lld, %d)",
+ e->input, e->shift);
+ }
+}
+
+static struct kunit_case shdi3_test_cases[] = {
+ KUNIT_CASE(shdi3_test_ashldi3),
+ KUNIT_CASE(shdi3_test_ashrdi3),
+ KUNIT_CASE(shdi3_test_lshrdi3),
+ {}
+};
+
+static struct kunit_suite shdi3_test_suite = {
+ .name = "shdi3",
+ .test_cases = shdi3_test_cases,
+};
+kunit_test_suite(shdi3_test_suite);
+
+MODULE_DESCRIPTION("Test cases for __ashldi3(), __ashrdi3(), and __lshrdi3()");
+MODULE_LICENSE("GPL");
--
2.53.0