linux/lib/test_bitfield.c
<<
>>
Prefs
   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 <linux/kernel.h>
   9#include <linux/module.h>
  10#include <linux/bitfield.h>
  11
  12#define CHECK_ENC_GET_U(tp, v, field, res) do {                         \
  13                {                                                       \
  14                        u##tp _res;                                     \
  15                                                                        \
  16                        _res = u##tp##_encode_bits(v, field);           \
  17                        if (_res != res) {                              \
  18                                pr_warn("u" #tp "_encode_bits(" #v ", " #field ") is 0x%llx != " #res "\n",\
  19                                        (u64)_res);                     \
  20                                return -EINVAL;                         \
  21                        }                                               \
  22                        if (u##tp##_get_bits(_res, field) != v)         \
  23                                return -EINVAL;                         \
  24                }                                                       \
  25        } while (0)
  26
  27#define CHECK_ENC_GET_LE(tp, v, field, res) do {                        \
  28                {                                                       \
  29                        __le##tp _res;                                  \
  30                                                                        \
  31                        _res = le##tp##_encode_bits(v, field);          \
  32                        if (_res != cpu_to_le##tp(res)) {               \
  33                                pr_warn("le" #tp "_encode_bits(" #v ", " #field ") is 0x%llx != 0x%llx\n",\
  34                                        (u64)le##tp##_to_cpu(_res),     \
  35                                        (u64)(res));                    \
  36                                return -EINVAL;                         \
  37                        }                                               \
  38                        if (le##tp##_get_bits(_res, field) != v)        \
  39                                return -EINVAL;                         \
  40                }                                                       \
  41        } while (0)
  42
  43#define CHECK_ENC_GET_BE(tp, v, field, res) do {                        \
  44                {                                                       \
  45                        __be##tp _res;                                  \
  46                                                                        \
  47                        _res = be##tp##_encode_bits(v, field);          \
  48                        if (_res != cpu_to_be##tp(res)) {               \
  49                                pr_warn("be" #tp "_encode_bits(" #v ", " #field ") is 0x%llx != 0x%llx\n",\
  50                                        (u64)be##tp##_to_cpu(_res),     \
  51                                        (u64)(res));                    \
  52                                return -EINVAL;                         \
  53                        }                                               \
  54                        if (be##tp##_get_bits(_res, field) != v)        \
  55                                return -EINVAL;                         \
  56                }                                                       \
  57        } while (0)
  58
  59#define CHECK_ENC_GET(tp, v, field, res) do {                           \
  60                CHECK_ENC_GET_U(tp, v, field, res);                     \
  61                CHECK_ENC_GET_LE(tp, v, field, res);                    \
  62                CHECK_ENC_GET_BE(tp, v, field, res);                    \
  63        } while (0)
  64
  65static int test_constants(void)
  66{
  67        /*
  68         * NOTE
  69         * This whole function compiles (or at least should, if everything
  70         * is going according to plan) to nothing after optimisation.
  71         */
  72
  73        CHECK_ENC_GET(16,  1, 0x000f, 0x0001);
  74        CHECK_ENC_GET(16,  3, 0x00f0, 0x0030);
  75        CHECK_ENC_GET(16,  5, 0x0f00, 0x0500);
  76        CHECK_ENC_GET(16,  7, 0xf000, 0x7000);
  77        CHECK_ENC_GET(16, 14, 0x000f, 0x000e);
  78        CHECK_ENC_GET(16, 15, 0x00f0, 0x00f0);
  79
  80        CHECK_ENC_GET_U(8,  1, 0x0f, 0x01);
  81        CHECK_ENC_GET_U(8,  3, 0xf0, 0x30);
  82        CHECK_ENC_GET_U(8, 14, 0x0f, 0x0e);
  83        CHECK_ENC_GET_U(8, 15, 0xf0, 0xf0);
  84
  85        CHECK_ENC_GET(32,  1, 0x00000f00, 0x00000100);
  86        CHECK_ENC_GET(32,  3, 0x0000f000, 0x00003000);
  87        CHECK_ENC_GET(32,  5, 0x000f0000, 0x00050000);
  88        CHECK_ENC_GET(32,  7, 0x00f00000, 0x00700000);
  89        CHECK_ENC_GET(32, 14, 0x0f000000, 0x0e000000);
  90        CHECK_ENC_GET(32, 15, 0xf0000000, 0xf0000000);
  91
  92        CHECK_ENC_GET(64,  1, 0x00000f0000000000ull, 0x0000010000000000ull);
  93        CHECK_ENC_GET(64,  3, 0x0000f00000000000ull, 0x0000300000000000ull);
  94        CHECK_ENC_GET(64,  5, 0x000f000000000000ull, 0x0005000000000000ull);
  95        CHECK_ENC_GET(64,  7, 0x00f0000000000000ull, 0x0070000000000000ull);
  96        CHECK_ENC_GET(64, 14, 0x0f00000000000000ull, 0x0e00000000000000ull);
  97        CHECK_ENC_GET(64, 15, 0xf000000000000000ull, 0xf000000000000000ull);
  98
  99        return 0;
 100}
 101
 102#define CHECK(tp, mask) do {                                            \
 103                u64 v;                                                  \
 104                                                                        \
 105                for (v = 0; v < 1 << hweight32(mask); v++)              \
 106                        if (tp##_encode_bits(v, mask) != v << __ffs64(mask)) \
 107                                return -EINVAL;                         \
 108        } while (0)
 109
 110static int test_variables(void)
 111{
 112        CHECK(u8, 0x0f);
 113        CHECK(u8, 0xf0);
 114        CHECK(u8, 0x38);
 115
 116        CHECK(u16, 0x0038);
 117        CHECK(u16, 0x0380);
 118        CHECK(u16, 0x3800);
 119        CHECK(u16, 0x8000);
 120
 121        CHECK(u32, 0x80000000);
 122        CHECK(u32, 0x7f000000);
 123        CHECK(u32, 0x07e00000);
 124        CHECK(u32, 0x00018000);
 125
 126        CHECK(u64, 0x8000000000000000ull);
 127        CHECK(u64, 0x7f00000000000000ull);
 128        CHECK(u64, 0x0001800000000000ull);
 129        CHECK(u64, 0x0000000080000000ull);
 130        CHECK(u64, 0x000000007f000000ull);
 131        CHECK(u64, 0x0000000018000000ull);
 132        CHECK(u64, 0x0000001f8000000ull);
 133
 134        return 0;
 135}
 136
 137static int __init test_bitfields(void)
 138{
 139        int ret = test_constants();
 140
 141        if (ret) {
 142                pr_warn("constant tests failed!\n");
 143                return ret;
 144        }
 145
 146        ret = test_variables();
 147        if (ret) {
 148                pr_warn("variable tests failed!\n");
 149                return ret;
 150        }
 151
 152#ifdef TEST_BITFIELD_COMPILE
 153        /* these should fail compilation */
 154        CHECK_ENC_GET(16, 16, 0x0f00, 0x1000);
 155        u32_encode_bits(7, 0x06000000);
 156
 157        /* this should at least give a warning */
 158        u16_encode_bits(0, 0x60000);
 159#endif
 160
 161        pr_info("tests passed\n");
 162
 163        return 0;
 164}
 165module_init(test_bitfields)
 166
 167MODULE_AUTHOR("Johannes Berg <johannes@sipsolutions.net>");
 168MODULE_LICENSE("GPL");
 169