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-rw-r--r--lib/test_bitfield.c168
1 files changed, 168 insertions, 0 deletions
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@sipsolutions.net>");
+MODULE_LICENSE("GPL");