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");