lib/test_bitfield.c

   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
  65 static 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
 110 static 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
 137 static 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 }
 165 module_init(test_bitfields)
 166
 167 MODULE_AUTHOR("Johannes Berg <johannes@sipsolutions.net>");
 168 MODULE_LICENSE("GPL");