linux/lib/bitfield_kunit.c
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   1// SPDX-License-Identifier: GPL-2.0+
   2/*
   3 * Test cases for bitfield helpers.
   4 */
   5
   6#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
   7
   8#include <kunit/test.h>
   9#include <linux/bitfield.h>
  10
  11#define CHECK_ENC_GET_U(tp, v, field, res) do {                         \
  12                {                                                       \
  13                        u##tp _res;                                     \
  14                                                                        \
  15                        _res = u##tp##_encode_bits(v, field);           \
  16                        KUNIT_ASSERT_FALSE_MSG(context, _res != res,    \
  17                                       "u" #tp "_encode_bits(" #v ", " #field ") is 0x%llx != " #res "\n",      \
  18                                       (u64)_res);                      \
  19                        KUNIT_ASSERT_FALSE(context,                     \
  20                                   u##tp##_get_bits(_res, field) != v); \
  21                }                                                       \
  22        } while (0)
  23
  24#define CHECK_ENC_GET_LE(tp, v, field, res) do {                        \
  25                {                                                       \
  26                        __le##tp _res;                                  \
  27                                                                        \
  28                        _res = le##tp##_encode_bits(v, field);          \
  29                        KUNIT_ASSERT_FALSE_MSG(context,                 \
  30                                       _res != cpu_to_le##tp(res),      \
  31                                       "le" #tp "_encode_bits(" #v ", " #field ") is 0x%llx != 0x%llx",\
  32                                       (u64)le##tp##_to_cpu(_res),      \
  33                                       (u64)(res));                     \
  34                        KUNIT_ASSERT_FALSE(context,                     \
  35                                   le##tp##_get_bits(_res, field) != v);\
  36                }                                                       \
  37        } while (0)
  38
  39#define CHECK_ENC_GET_BE(tp, v, field, res) do {                        \
  40                {                                                       \
  41                        __be##tp _res;                                  \
  42                                                                        \
  43                        _res = be##tp##_encode_bits(v, field);          \
  44                        KUNIT_ASSERT_FALSE_MSG(context,                 \
  45                                       _res != cpu_to_be##tp(res),      \
  46                                       "be" #tp "_encode_bits(" #v ", " #field ") is 0x%llx != 0x%llx", \
  47                                       (u64)be##tp##_to_cpu(_res),      \
  48                                       (u64)(res));                     \
  49                        KUNIT_ASSERT_FALSE(context,                     \
  50                                   be##tp##_get_bits(_res, field) != v);\
  51                }                                                       \
  52        } while (0)
  53
  54#define CHECK_ENC_GET(tp, v, field, res) do {                           \
  55                CHECK_ENC_GET_U(tp, v, field, res);                     \
  56                CHECK_ENC_GET_LE(tp, v, field, res);                    \
  57                CHECK_ENC_GET_BE(tp, v, field, res);                    \
  58        } while (0)
  59
  60static void __init test_bitfields_constants(struct kunit *context)
  61{
  62        /*
  63         * NOTE
  64         * This whole function compiles (or at least should, if everything
  65         * is going according to plan) to nothing after optimisation.
  66         */
  67
  68        CHECK_ENC_GET(16,  1, 0x000f, 0x0001);
  69        CHECK_ENC_GET(16,  3, 0x00f0, 0x0030);
  70        CHECK_ENC_GET(16,  5, 0x0f00, 0x0500);
  71        CHECK_ENC_GET(16,  7, 0xf000, 0x7000);
  72        CHECK_ENC_GET(16, 14, 0x000f, 0x000e);
  73        CHECK_ENC_GET(16, 15, 0x00f0, 0x00f0);
  74
  75        CHECK_ENC_GET_U(8,  1, 0x0f, 0x01);
  76        CHECK_ENC_GET_U(8,  3, 0xf0, 0x30);
  77        CHECK_ENC_GET_U(8, 14, 0x0f, 0x0e);
  78        CHECK_ENC_GET_U(8, 15, 0xf0, 0xf0);
  79
  80        CHECK_ENC_GET(32,  1, 0x00000f00, 0x00000100);
  81        CHECK_ENC_GET(32,  3, 0x0000f000, 0x00003000);
  82        CHECK_ENC_GET(32,  5, 0x000f0000, 0x00050000);
  83        CHECK_ENC_GET(32,  7, 0x00f00000, 0x00700000);
  84        CHECK_ENC_GET(32, 14, 0x0f000000, 0x0e000000);
  85        CHECK_ENC_GET(32, 15, 0xf0000000, 0xf0000000);
  86
  87        CHECK_ENC_GET(64,  1, 0x00000f0000000000ull, 0x0000010000000000ull);
  88        CHECK_ENC_GET(64,  3, 0x0000f00000000000ull, 0x0000300000000000ull);
  89        CHECK_ENC_GET(64,  5, 0x000f000000000000ull, 0x0005000000000000ull);
  90        CHECK_ENC_GET(64,  7, 0x00f0000000000000ull, 0x0070000000000000ull);
  91        CHECK_ENC_GET(64, 14, 0x0f00000000000000ull, 0x0e00000000000000ull);
  92        CHECK_ENC_GET(64, 15, 0xf000000000000000ull, 0xf000000000000000ull);
  93}
  94
  95#define CHECK(tp, mask) do {                                            \
  96                u64 v;                                                  \
  97                                                                        \
  98                for (v = 0; v < 1 << hweight32(mask); v++)              \
  99                        KUNIT_ASSERT_FALSE(context,                     \
 100                                tp##_encode_bits(v, mask) != v << __ffs64(mask));\
 101        } while (0)
 102
 103static void __init test_bitfields_variables(struct kunit *context)
 104{
 105        CHECK(u8, 0x0f);
 106        CHECK(u8, 0xf0);
 107        CHECK(u8, 0x38);
 108
 109        CHECK(u16, 0x0038);
 110        CHECK(u16, 0x0380);
 111        CHECK(u16, 0x3800);
 112        CHECK(u16, 0x8000);
 113
 114        CHECK(u32, 0x80000000);
 115        CHECK(u32, 0x7f000000);
 116        CHECK(u32, 0x07e00000);
 117        CHECK(u32, 0x00018000);
 118
 119        CHECK(u64, 0x8000000000000000ull);
 120        CHECK(u64, 0x7f00000000000000ull);
 121        CHECK(u64, 0x0001800000000000ull);
 122        CHECK(u64, 0x0000000080000000ull);
 123        CHECK(u64, 0x000000007f000000ull);
 124        CHECK(u64, 0x0000000018000000ull);
 125        CHECK(u64, 0x0000001f8000000ull);
 126}
 127
 128#ifdef TEST_BITFIELD_COMPILE
 129static void __init test_bitfields_compile(struct kunit *context)
 130{
 131        /* these should fail compilation */
 132        CHECK_ENC_GET(16, 16, 0x0f00, 0x1000);
 133        u32_encode_bits(7, 0x06000000);
 134
 135        /* this should at least give a warning */
 136        u16_encode_bits(0, 0x60000);
 137}
 138#endif
 139
 140static struct kunit_case __refdata bitfields_test_cases[] = {
 141        KUNIT_CASE(test_bitfields_constants),
 142        KUNIT_CASE(test_bitfields_variables),
 143        {}
 144};
 145
 146static struct kunit_suite bitfields_test_suite = {
 147        .name = "bitfields",
 148        .test_cases = bitfields_test_cases,
 149};
 150
 151kunit_test_suites(&bitfields_test_suite);
 152
 153MODULE_AUTHOR("Johannes Berg <johannes@sipsolutions.net>");
 154MODULE_LICENSE("GPL");
 155