xref: /linux/tools/testing/selftests/bpf/prog_tests/btf_permute.c (revision 6f7e6393d1ce636bb7ec77a7fe7b77458fddf701)
1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (c) 2026 Xiaomi */
3 
4 #include <test_progs.h>
5 #include <bpf/btf.h>
6 #include "btf_helpers.h"
7 
8 static void permute_base_check(struct btf *btf)
9 {
10 	VALIDATE_RAW_BTF(
11 		btf,
12 		"[1] STRUCT 's2' size=4 vlen=1\n"
13 		"\t'm' type_id=4 bits_offset=0",
14 		"[2] FUNC 'f' type_id=6 linkage=static",
15 		"[3] PTR '(anon)' type_id=4",
16 		"[4] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED",
17 		"[5] STRUCT 's1' size=4 vlen=1\n"
18 		"\t'm' type_id=4 bits_offset=0",
19 		"[6] FUNC_PROTO '(anon)' ret_type_id=4 vlen=1\n"
20 		"\t'p' type_id=3");
21 }
22 
23 /* Ensure btf__permute works as expected in the base-BTF scenario */
24 static void test_permute_base(void)
25 {
26 	struct btf *btf;
27 	__u32 permute_ids[7];
28 	int err;
29 
30 	btf = btf__new_empty();
31 	if (!ASSERT_OK_PTR(btf, "empty_main_btf"))
32 		return;
33 
34 	btf__add_int(btf, "int", 4, BTF_INT_SIGNED);	/* [1] int */
35 	btf__add_ptr(btf, 1);				/* [2] ptr to int */
36 	btf__add_struct(btf, "s1", 4);			/* [3] struct s1 { */
37 	btf__add_field(btf, "m", 1, 0, 0);		/*       int m; */
38 							/* } */
39 	btf__add_struct(btf, "s2", 4);			/* [4] struct s2 { */
40 	btf__add_field(btf, "m", 1, 0, 0);		/*       int m; */
41 							/* } */
42 	btf__add_func_proto(btf, 1);			/* [5] int (*)(int *p); */
43 	btf__add_func_param(btf, "p", 2);
44 	btf__add_func(btf, "f", BTF_FUNC_STATIC, 5);	/* [6] int f(int *p); */
45 
46 	VALIDATE_RAW_BTF(
47 		btf,
48 		"[1] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED",
49 		"[2] PTR '(anon)' type_id=1",
50 		"[3] STRUCT 's1' size=4 vlen=1\n"
51 		"\t'm' type_id=1 bits_offset=0",
52 		"[4] STRUCT 's2' size=4 vlen=1\n"
53 		"\t'm' type_id=1 bits_offset=0",
54 		"[5] FUNC_PROTO '(anon)' ret_type_id=1 vlen=1\n"
55 		"\t'p' type_id=2",
56 		"[6] FUNC 'f' type_id=5 linkage=static");
57 
58 	permute_ids[0] = 0; /* [0] -> [0] */
59 	permute_ids[1] = 4; /* [1] -> [4] */
60 	permute_ids[2] = 3; /* [2] -> [3] */
61 	permute_ids[3] = 5; /* [3] -> [5] */
62 	permute_ids[4] = 1; /* [4] -> [1] */
63 	permute_ids[5] = 6; /* [5] -> [6] */
64 	permute_ids[6] = 2; /* [6] -> [2] */
65 	err = btf__permute(btf, permute_ids, ARRAY_SIZE(permute_ids), NULL);
66 	if (!ASSERT_OK(err, "btf__permute_base"))
67 		goto done;
68 	permute_base_check(btf);
69 
70 	/* ids[0] must be 0 for base BTF */
71 	permute_ids[0] = 4; /* [0] -> [0] */
72 	permute_ids[1] = 0; /* [1] -> [4] */
73 	permute_ids[2] = 3; /* [2] -> [3] */
74 	permute_ids[3] = 5; /* [3] -> [5] */
75 	permute_ids[4] = 1; /* [4] -> [1] */
76 	permute_ids[5] = 6; /* [5] -> [6] */
77 	permute_ids[6] = 2; /* [6] -> [2] */
78 	err = btf__permute(btf, permute_ids, ARRAY_SIZE(permute_ids), NULL);
79 	if (!ASSERT_ERR(err, "btf__permute_base"))
80 		goto done;
81 	/* BTF is not modified */
82 	permute_base_check(btf);
83 
84 	/* id_map_cnt is invalid */
85 	permute_ids[0] = 0; /* [0] -> [0] */
86 	permute_ids[1] = 4; /* [1] -> [4] */
87 	permute_ids[2] = 3; /* [2] -> [3] */
88 	permute_ids[3] = 5; /* [3] -> [5] */
89 	permute_ids[4] = 1; /* [4] -> [1] */
90 	permute_ids[5] = 6; /* [5] -> [6] */
91 	permute_ids[6] = 2; /* [6] -> [2] */
92 	err = btf__permute(btf, permute_ids, ARRAY_SIZE(permute_ids) - 1, NULL);
93 	if (!ASSERT_ERR(err, "btf__permute_base"))
94 		goto done;
95 	/* BTF is not modified */
96 	permute_base_check(btf);
97 
98 	/* Multiple types can not be mapped to the same ID */
99 	permute_ids[0] = 0;
100 	permute_ids[1] = 4;
101 	permute_ids[2] = 4;
102 	permute_ids[3] = 5;
103 	permute_ids[4] = 1;
104 	permute_ids[5] = 6;
105 	permute_ids[6] = 2;
106 	err = btf__permute(btf, permute_ids, ARRAY_SIZE(permute_ids), NULL);
107 	if (!ASSERT_ERR(err, "btf__permute_base"))
108 		goto done;
109 	/* BTF is not modified */
110 	permute_base_check(btf);
111 
112 	/* Type ID must be valid */
113 	permute_ids[0] = 0;
114 	permute_ids[1] = 4;
115 	permute_ids[2] = 3;
116 	permute_ids[3] = 5;
117 	permute_ids[4] = 1;
118 	permute_ids[5] = 7;
119 	permute_ids[6] = 2;
120 	err = btf__permute(btf, permute_ids, ARRAY_SIZE(permute_ids), NULL);
121 	if (!ASSERT_ERR(err, "btf__permute_base"))
122 		goto done;
123 	/* BTF is not modified */
124 	permute_base_check(btf);
125 
126 done:
127 	btf__free(btf);
128 }
129 
130 static void permute_split_check(struct btf *btf)
131 {
132 	VALIDATE_RAW_BTF(
133 		btf,
134 		"[1] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED",
135 		"[2] PTR '(anon)' type_id=1",
136 		"[3] STRUCT 's2' size=4 vlen=1\n"
137 		"\t'm' type_id=1 bits_offset=0",
138 		"[4] FUNC 'f' type_id=5 linkage=static",
139 		"[5] FUNC_PROTO '(anon)' ret_type_id=1 vlen=1\n"
140 		"\t'p' type_id=2",
141 		"[6] STRUCT 's1' size=4 vlen=1\n"
142 		"\t'm' type_id=1 bits_offset=0");
143 }
144 
145 /* Ensure btf__permute works as expected in the split-BTF scenario */
146 static void test_permute_split(void)
147 {
148 	struct btf *split_btf = NULL, *base_btf = NULL;
149 	__u32 permute_ids[4];
150 	int err, start_id;
151 
152 	base_btf = btf__new_empty();
153 	if (!ASSERT_OK_PTR(base_btf, "empty_main_btf"))
154 		return;
155 
156 	btf__add_int(base_btf, "int", 4, BTF_INT_SIGNED);	/* [1] int */
157 	btf__add_ptr(base_btf, 1);				/* [2] ptr to int */
158 	VALIDATE_RAW_BTF(
159 		base_btf,
160 		"[1] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED",
161 		"[2] PTR '(anon)' type_id=1");
162 	split_btf = btf__new_empty_split(base_btf);
163 	if (!ASSERT_OK_PTR(split_btf, "empty_split_btf"))
164 		goto cleanup;
165 	btf__add_struct(split_btf, "s1", 4);			/* [3] struct s1 { */
166 	btf__add_field(split_btf, "m", 1, 0, 0);		/*   int m; */
167 								/* } */
168 	btf__add_struct(split_btf, "s2", 4);			/* [4] struct s2 { */
169 	btf__add_field(split_btf, "m", 1, 0, 0);		/*   int m; */
170 								/* } */
171 	btf__add_func_proto(split_btf, 1);			/* [5] int (*)(int p); */
172 	btf__add_func_param(split_btf, "p", 2);
173 	btf__add_func(split_btf, "f", BTF_FUNC_STATIC, 5);	/* [6] int f(int *p); */
174 
175 	VALIDATE_RAW_BTF(
176 		split_btf,
177 		"[1] INT 'int' size=4 bits_offset=0 nr_bits=32 encoding=SIGNED",
178 		"[2] PTR '(anon)' type_id=1",
179 		"[3] STRUCT 's1' size=4 vlen=1\n"
180 		"\t'm' type_id=1 bits_offset=0",
181 		"[4] STRUCT 's2' size=4 vlen=1\n"
182 		"\t'm' type_id=1 bits_offset=0",
183 		"[5] FUNC_PROTO '(anon)' ret_type_id=1 vlen=1\n"
184 		"\t'p' type_id=2",
185 		"[6] FUNC 'f' type_id=5 linkage=static");
186 
187 	start_id = btf__type_cnt(base_btf);
188 	permute_ids[3 - start_id] = 6; /* [3] -> [6] */
189 	permute_ids[4 - start_id] = 3; /* [4] -> [3] */
190 	permute_ids[5 - start_id] = 5; /* [5] -> [5] */
191 	permute_ids[6 - start_id] = 4; /* [6] -> [4] */
192 	err = btf__permute(split_btf, permute_ids, ARRAY_SIZE(permute_ids), NULL);
193 	if (!ASSERT_OK(err, "btf__permute_split"))
194 		goto cleanup;
195 	permute_split_check(split_btf);
196 
197 	/*
198 	 * For split BTF, id_map_cnt must equal to the number of types
199 	 * added on top of base BTF
200 	 */
201 	permute_ids[3 - start_id] = 4;
202 	permute_ids[4 - start_id] = 3;
203 	permute_ids[5 - start_id] = 5;
204 	permute_ids[6 - start_id] = 6;
205 	err = btf__permute(split_btf, permute_ids, ARRAY_SIZE(permute_ids) - 1, NULL);
206 	if (!ASSERT_ERR(err, "btf__permute_split"))
207 		goto cleanup;
208 	/* BTF is not modified */
209 	permute_split_check(split_btf);
210 
211 	/* Multiple types can not be mapped to the same ID */
212 	permute_ids[3 - start_id] = 4;
213 	permute_ids[4 - start_id] = 3;
214 	permute_ids[5 - start_id] = 3;
215 	permute_ids[6 - start_id] = 6;
216 	err = btf__permute(split_btf, permute_ids, ARRAY_SIZE(permute_ids), NULL);
217 	if (!ASSERT_ERR(err, "btf__permute_split"))
218 		goto cleanup;
219 	/* BTF is not modified */
220 	permute_split_check(split_btf);
221 
222 	/* Can not map to base ID */
223 	permute_ids[3 - start_id] = 4;
224 	permute_ids[4 - start_id] = 2;
225 	permute_ids[5 - start_id] = 5;
226 	permute_ids[6 - start_id] = 6;
227 	err = btf__permute(split_btf, permute_ids, ARRAY_SIZE(permute_ids), NULL);
228 	if (!ASSERT_ERR(err, "btf__permute_split"))
229 		goto cleanup;
230 	/* BTF is not modified */
231 	permute_split_check(split_btf);
232 
233 cleanup:
234 	btf__free(split_btf);
235 	btf__free(base_btf);
236 }
237 
238 void test_btf_permute(void)
239 {
240 	if (test__start_subtest("permute_base"))
241 		test_permute_base();
242 	if (test__start_subtest("permute_split"))
243 		test_permute_split();
244 }
245