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