tools/testing/selftests/bpf/prog_tests/resolve_btfids.c

   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, 1)
  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 >= 0)
  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__type_cnt(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 void 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;
 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;
 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                         if (!ASSERT_LE(test_set.ids[i - 1], test_set.ids[i], "sort_check"))
 164                                 return;
 165                 }
 166         }
 167 }