Add tests for the bitfield helpers. The constant ones will all
be folded to nothing by the compiler (if everything is correct
in the header file), and the variable ones do some tests against
open-coding the necessary shifts.
A few test cases that should fail/warn compilation are provided
under ifdef.
Suggested-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>
Reviewed-by: Andy Shevchenko <andy.shevchenko@xxxxxxxxx>
Signed-off-by: Johannes Berg <johannes@xxxxxxxxxxxxxxxx>
---
lib/Kconfig.debug | 7 +++
lib/Makefile | 1 +
lib/test_bitfield.c | 168 ++++++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 176 insertions(+)
create mode 100644 lib/test_bitfield.c
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug
index eb885942eb0f..b0870377b4d1 100644
--- a/lib/Kconfig.debug
+++ b/lib/Kconfig.debug
@@ -1799,6 +1799,13 @@ config TEST_BITMAP
If unsure, say N.
+config TEST_BITFIELD
+ tristate "Test bitfield functions at runtime"
+ help
+ Enable this option to test the bitfield functions at boot.
+
+ If unsure, say N.
+
config TEST_UUID
tristate "Test functions located in the uuid module at runtime"
diff --git a/lib/Makefile b/lib/Makefile
index 84c6dcb31fbb..02ab4c1a64d1 100644
--- a/lib/Makefile
+++ b/lib/Makefile
@@ -68,6 +68,7 @@ obj-$(CONFIG_TEST_STATIC_KEYS) += test_static_keys.o
obj-$(CONFIG_TEST_STATIC_KEYS) += test_static_key_base.o
obj-$(CONFIG_TEST_PRINTF) += test_printf.o
obj-$(CONFIG_TEST_BITMAP) += test_bitmap.o
+obj-$(CONFIG_TEST_BITFIELD) += test_bitfield.o
obj-$(CONFIG_TEST_UUID) += test_uuid.o
obj-$(CONFIG_TEST_PARMAN) += test_parman.o
obj-$(CONFIG_TEST_KMOD) += test_kmod.o
diff --git a/lib/test_bitfield.c b/lib/test_bitfield.c
new file mode 100644
index 000000000000..5b8f4108662d
--- /dev/null
+++ b/lib/test_bitfield.c
@@ -0,0 +1,168 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Test cases for bitfield helpers.
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/bitfield.h>
+
+#define CHECK_ENC_GET_U(tp, v, field, res) do { \
+ { \
+ u##tp _res; \
+ \
+ _res = u##tp##_encode_bits(v, field); \
+ if (_res != res) { \
+ pr_warn("u" #tp "_encode_bits(" #v ", " #field ") is 0x%llx != " #res "\n",\
+ (u64)_res); \
+ return -EINVAL; \
+ } \
+ if (u##tp##_get_bits(_res, field) != v) \
+ return -EINVAL; \
+ } \
+ } while (0)
+
+#define CHECK_ENC_GET_LE(tp, v, field, res) do { \
+ { \
+ __le##tp _res; \
+ \
+ _res = le##tp##_encode_bits(v, field); \
+ if (_res != cpu_to_le##tp(res)) { \
+ pr_warn("le" #tp "_encode_bits(" #v ", " #field ") is 0x%llx != 0x%llx\n",\
+ (u64)le##tp##_to_cpu(_res), \
+ (u64)(res)); \
+ return -EINVAL; \
+ } \
+ if (le##tp##_get_bits(_res, field) != v) \
+ return -EINVAL; \
+ } \
+ } while (0)
+
+#define CHECK_ENC_GET_BE(tp, v, field, res) do { \
+ { \
+ __be##tp _res; \
+ \
+ _res = be##tp##_encode_bits(v, field); \
+ if (_res != cpu_to_be##tp(res)) { \
+ pr_warn("be" #tp "_encode_bits(" #v ", " #field ") is 0x%llx != 0x%llx\n",\
+ (u64)be##tp##_to_cpu(_res), \
+ (u64)(res)); \
+ return -EINVAL; \
+ } \
+ if (be##tp##_get_bits(_res, field) != v) \
+ return -EINVAL; \
+ } \
+ } while (0)
+
+#define CHECK_ENC_GET(tp, v, field, res) do { \
+ CHECK_ENC_GET_U(tp, v, field, res); \
+ CHECK_ENC_GET_LE(tp, v, field, res); \
+ CHECK_ENC_GET_BE(tp, v, field, res); \
+ } while (0)
+
+static int test_constants(void)
+{
+ /*
+ * NOTE
+ * This whole function compiles (or at least should, if everything
+ * is going according to plan) to nothing after optimisation.
+ */
+
+ CHECK_ENC_GET(16, 1, 0x000f, 0x0001);
+ CHECK_ENC_GET(16, 3, 0x00f0, 0x0030);
+ CHECK_ENC_GET(16, 5, 0x0f00, 0x0500);
+ CHECK_ENC_GET(16, 7, 0xf000, 0x7000);
+ CHECK_ENC_GET(16, 14, 0x000f, 0x000e);
+ CHECK_ENC_GET(16, 15, 0x00f0, 0x00f0);
+
+ CHECK_ENC_GET_U(8, 1, 0x0f, 0x01);
+ CHECK_ENC_GET_U(8, 3, 0xf0, 0x30);
+ CHECK_ENC_GET_U(8, 14, 0x0f, 0x0e);
+ CHECK_ENC_GET_U(8, 15, 0xf0, 0xf0);
+
+ CHECK_ENC_GET(32, 1, 0x00000f00, 0x00000100);
+ CHECK_ENC_GET(32, 3, 0x0000f000, 0x00003000);
+ CHECK_ENC_GET(32, 5, 0x000f0000, 0x00050000);
+ CHECK_ENC_GET(32, 7, 0x00f00000, 0x00700000);
+ CHECK_ENC_GET(32, 14, 0x0f000000, 0x0e000000);
+ CHECK_ENC_GET(32, 15, 0xf0000000, 0xf0000000);
+
+ CHECK_ENC_GET(64, 1, 0x00000f0000000000ull, 0x0000010000000000ull);
+ CHECK_ENC_GET(64, 3, 0x0000f00000000000ull, 0x0000300000000000ull);
+ CHECK_ENC_GET(64, 5, 0x000f000000000000ull, 0x0005000000000000ull);
+ CHECK_ENC_GET(64, 7, 0x00f0000000000000ull, 0x0070000000000000ull);
+ CHECK_ENC_GET(64, 14, 0x0f00000000000000ull, 0x0e00000000000000ull);
+ CHECK_ENC_GET(64, 15, 0xf000000000000000ull, 0xf000000000000000ull);
+
+ return 0;
+}
+
+#define CHECK(tp, mask) do { \
+ u64 v; \
+ \
+ for (v = 0; v < 1 << hweight32(mask); v++) \
+ if (tp##_encode_bits(v, mask) != v << __ffs64(mask)) \
+ return -EINVAL; \
+ } while (0)
+
+static int test_variables(void)
+{
+ CHECK(u8, 0x0f);
+ CHECK(u8, 0xf0);
+ CHECK(u8, 0x38);
+
+ CHECK(u16, 0x0038);
+ CHECK(u16, 0x0380);
+ CHECK(u16, 0x3800);
+ CHECK(u16, 0x8000);
+
+ CHECK(u32, 0x80000000);
+ CHECK(u32, 0x7f000000);
+ CHECK(u32, 0x07e00000);
+ CHECK(u32, 0x00018000);
+
+ CHECK(u64, 0x8000000000000000ull);
+ CHECK(u64, 0x7f00000000000000ull);
+ CHECK(u64, 0x0001800000000000ull);
+ CHECK(u64, 0x0000000080000000ull);
+ CHECK(u64, 0x000000007f000000ull);
+ CHECK(u64, 0x0000000018000000ull);
+ CHECK(u64, 0x0000001f8000000ull);
+
+ return 0;
+}
+
+static int __init test_bitfields(void)
+{
+ int ret = test_constants();
+
+ if (ret) {
+ pr_warn("constant tests failed!\n");
+ return ret;
+ }
+
+ ret = test_variables();
+ if (ret) {
+ pr_warn("variable tests failed!\n");
+ return ret;
+ }
+
+#ifdef TEST_BITFIELD_COMPILE
+ /* these should fail compilation */
+ CHECK_ENC_GET(16, 16, 0x0f00, 0x1000);
+ u32_encode_bits(7, 0x06000000);
+
+ /* this should at least give a warning */
+ u16_encode_bits(0, 0x60000);
+#endif
+
+ pr_info("tests passed\n");
+
+ return 0;
+}
+module_init(test_bitfields)
+
+MODULE_AUTHOR("Johannes Berg <johannes@xxxxxxxxxxxxxxxx>");
+MODULE_LICENSE("GPL");
--
2.14.4
