xref: /linux/tools/testing/selftests/bpf/prog_tests/resolve_btfids.c (revision ec8a42e7343234802b9054874fe01810880289ce)
1 // SPDX-License-Identifier: GPL-2.0
2 
3 #include <linux/err.h>
4 #include <string.h>
5 #include <bpf/btf.h>
6 #include <bpf/libbpf.h>
7 #include <linux/btf.h>
8 #include <linux/kernel.h>
9 #define CONFIG_DEBUG_INFO_BTF
10 #include <linux/btf_ids.h>
11 #include "test_progs.h"
12 
13 static int duration;
14 
15 struct symbol {
16 	const char	*name;
17 	int		 type;
18 	int		 id;
19 };
20 
21 struct symbol test_symbols[] = {
22 	{ "unused",  BTF_KIND_UNKN,     0 },
23 	{ "S",       BTF_KIND_TYPEDEF, -1 },
24 	{ "T",       BTF_KIND_TYPEDEF, -1 },
25 	{ "U",       BTF_KIND_TYPEDEF, -1 },
26 	{ "S",       BTF_KIND_STRUCT,  -1 },
27 	{ "U",       BTF_KIND_UNION,   -1 },
28 	{ "func",    BTF_KIND_FUNC,    -1 },
29 };
30 
31 /* Align the .BTF_ids section to 4 bytes */
32 asm (
33 ".pushsection " BTF_IDS_SECTION " ,\"a\"; \n"
34 ".balign 4, 0;                            \n"
35 ".popsection;                             \n");
36 
37 BTF_ID_LIST(test_list_local)
38 BTF_ID_UNUSED
39 BTF_ID(typedef, S)
40 BTF_ID(typedef, T)
41 BTF_ID(typedef, U)
42 BTF_ID(struct,  S)
43 BTF_ID(union,   U)
44 BTF_ID(func,    func)
45 
46 extern __u32 test_list_global[];
47 BTF_ID_LIST_GLOBAL(test_list_global)
48 BTF_ID_UNUSED
49 BTF_ID(typedef, S)
50 BTF_ID(typedef, T)
51 BTF_ID(typedef, U)
52 BTF_ID(struct,  S)
53 BTF_ID(union,   U)
54 BTF_ID(func,    func)
55 
56 BTF_SET_START(test_set)
57 BTF_ID(typedef, S)
58 BTF_ID(typedef, T)
59 BTF_ID(typedef, U)
60 BTF_ID(struct,  S)
61 BTF_ID(union,   U)
62 BTF_ID(func,    func)
63 BTF_SET_END(test_set)
64 
65 static int
66 __resolve_symbol(struct btf *btf, int type_id)
67 {
68 	const struct btf_type *type;
69 	const char *str;
70 	unsigned int i;
71 
72 	type = btf__type_by_id(btf, type_id);
73 	if (!type) {
74 		PRINT_FAIL("Failed to get type for ID %d\n", type_id);
75 		return -1;
76 	}
77 
78 	for (i = 0; i < ARRAY_SIZE(test_symbols); i++) {
79 		if (test_symbols[i].id != -1)
80 			continue;
81 
82 		if (BTF_INFO_KIND(type->info) != test_symbols[i].type)
83 			continue;
84 
85 		str = btf__name_by_offset(btf, type->name_off);
86 		if (!str) {
87 			PRINT_FAIL("Failed to get name for BTF ID %d\n", type_id);
88 			return -1;
89 		}
90 
91 		if (!strcmp(str, test_symbols[i].name))
92 			test_symbols[i].id = type_id;
93 	}
94 
95 	return 0;
96 }
97 
98 static int resolve_symbols(void)
99 {
100 	struct btf *btf;
101 	int type_id;
102 	__u32 nr;
103 
104 	btf = btf__parse_elf("btf_data.o", NULL);
105 	if (CHECK(libbpf_get_error(btf), "resolve",
106 		  "Failed to load BTF from btf_data.o\n"))
107 		return -1;
108 
109 	nr = btf__get_nr_types(btf);
110 
111 	for (type_id = 1; type_id <= nr; type_id++) {
112 		if (__resolve_symbol(btf, type_id))
113 			break;
114 	}
115 
116 	btf__free(btf);
117 	return 0;
118 }
119 
120 int test_resolve_btfids(void)
121 {
122 	__u32 *test_list, *test_lists[] = { test_list_local, test_list_global };
123 	unsigned int i, j;
124 	int ret = 0;
125 
126 	if (resolve_symbols())
127 		return -1;
128 
129 	/* Check BTF_ID_LIST(test_list_local) and
130 	 * BTF_ID_LIST_GLOBAL(test_list_global) IDs
131 	 */
132 	for (j = 0; j < ARRAY_SIZE(test_lists); j++) {
133 		test_list = test_lists[j];
134 		for (i = 0; i < ARRAY_SIZE(test_symbols); i++) {
135 			ret = CHECK(test_list[i] != test_symbols[i].id,
136 				    "id_check",
137 				    "wrong ID for %s (%d != %d)\n",
138 				    test_symbols[i].name,
139 				    test_list[i], test_symbols[i].id);
140 			if (ret)
141 				return ret;
142 		}
143 	}
144 
145 	/* Check BTF_SET_START(test_set) IDs */
146 	for (i = 0; i < test_set.cnt; i++) {
147 		bool found = false;
148 
149 		for (j = 0; j < ARRAY_SIZE(test_symbols); j++) {
150 			if (test_symbols[j].id != test_set.ids[i])
151 				continue;
152 			found = true;
153 			break;
154 		}
155 
156 		ret = CHECK(!found, "id_check",
157 			    "ID %d not found in test_symbols\n",
158 			    test_set.ids[i]);
159 		if (ret)
160 			break;
161 
162 		if (i > 0) {
163 			ret = CHECK(test_set.ids[i - 1] > test_set.ids[i],
164 				    "sort_check",
165 				    "test_set is not sorted\n");
166 			if (ret)
167 				break;
168 		}
169 	}
170 
171 	return ret;
172 }
173