1 // SPDX-License-Identifier: GPL-2.0 2 #include <test_progs.h> 3 #include <bpf/btf.h> 4 5 #define TRACEFS "/sys/kernel/tracing" 6 #define DEBUGFS_TRACING "/sys/kernel/debug/tracing" 7 #define EVENT_SUBPATH "events/bpf_testmod/bpf_testmod_test_read/btf_ids" 8 9 struct btf_ids_info { 10 __u32 obj_id; 11 __u32 raw_id; 12 __u32 tp_id; 13 }; 14 15 static const char *btf_ids_path(char *buf, size_t sz) 16 { 17 if (access(TRACEFS "/trace", F_OK) == 0) 18 snprintf(buf, sz, "%s/%s", TRACEFS, EVENT_SUBPATH); 19 else 20 snprintf(buf, sz, "%s/%s", DEBUGFS_TRACING, EVENT_SUBPATH); 21 return buf; 22 } 23 24 static int read_btf_ids(struct btf_ids_info *info) 25 { 26 char path[256], buf[256]; 27 int fd, n; 28 29 fd = open(btf_ids_path(path, sizeof(path)), O_RDONLY); 30 if (fd < 0) 31 return -errno; 32 33 n = read(fd, buf, sizeof(buf) - 1); 34 close(fd); 35 if (n <= 0) 36 return -EIO; 37 buf[n] = '\0'; 38 39 if (sscanf(buf, 40 "btf_obj_id: %u\nraw_btf_id: %u\ntp_btf_id: %u\n", 41 &info->obj_id, &info->raw_id, &info->tp_id) != 3) 42 return -EINVAL; 43 return 0; 44 } 45 46 static const char *param_name(struct btf *btf, const struct btf_param *p) 47 { 48 return btf__name_by_offset(btf, p->name_off); 49 } 50 51 static const char *member_name(struct btf *btf, const struct btf_member *m) 52 { 53 return btf__name_by_offset(btf, m->name_off); 54 } 55 56 void test_tp_btf_ids(void) 57 { 58 const struct btf_type *proto_t, *rec_t; 59 const struct btf_param *params; 60 const struct btf_member *members; 61 struct btf_ids_info info; 62 struct btf *vmlinux_btf, *btf; 63 const char *name; 64 int err; 65 66 if (!env.has_testmod) { 67 test__skip(); 68 return; 69 } 70 71 err = read_btf_ids(&info); 72 if (!ASSERT_OK(err, "read btf_ids")) 73 return; 74 75 ASSERT_GT(info.obj_id, 0, "obj_id non-zero"); 76 ASSERT_GT(info.raw_id, 0, "raw_id non-zero"); 77 ASSERT_GT(info.tp_id, 0, "tp_id non-zero"); 78 79 vmlinux_btf = btf__load_vmlinux_btf(); 80 if (!ASSERT_OK_PTR(vmlinux_btf, "load vmlinux BTF")) 81 return; 82 83 /* Module BTF is split BTF; load with vmlinux as base. */ 84 btf = btf__load_from_kernel_by_id_split(info.obj_id, vmlinux_btf); 85 if (!ASSERT_OK_PTR(btf, "load module BTF")) { 86 btf__free(vmlinux_btf); 87 return; 88 } 89 90 /* 91 * raw_btf_id should be the FUNC_PROTO of __bpf_trace_<call>: 92 * void *__data, struct task_struct *task, 93 * struct bpf_testmod_test_read_ctx *ctx 94 */ 95 proto_t = btf__type_by_id(btf, info.raw_id); 96 if (!ASSERT_OK_PTR(proto_t, "raw type_by_id")) 97 goto out; 98 if (!ASSERT_TRUE(btf_is_func_proto(proto_t), "raw is FUNC_PROTO")) 99 goto out; 100 if (!ASSERT_EQ(btf_vlen(proto_t), 3, "func_proto arg count")) 101 goto out; 102 103 params = btf_params(proto_t); 104 ASSERT_STREQ(param_name(btf, ¶ms[0]), "__data", "arg0 name"); 105 ASSERT_STREQ(param_name(btf, ¶ms[1]), "task", "arg1 name"); 106 ASSERT_STREQ(param_name(btf, ¶ms[2]), "ctx", "arg2 name"); 107 108 /* 109 * tp_btf_id should be STRUCT trace_event_raw_<call> with the 110 * fields declared by TP_STRUCT__entry plus the common header. 111 */ 112 rec_t = btf__type_by_id(btf, info.tp_id); 113 if (!ASSERT_OK_PTR(rec_t, "tp type_by_id")) 114 goto out; 115 if (!ASSERT_TRUE(btf_is_struct(rec_t), "tp is STRUCT")) 116 goto out; 117 name = btf__name_by_offset(btf, rec_t->name_off); 118 ASSERT_STREQ(name, "trace_event_raw_bpf_testmod_test_read", 119 "tp struct name"); 120 if (!ASSERT_GE(btf_vlen(rec_t), 5, "tp struct field count")) 121 goto out; 122 123 members = btf_members(rec_t); 124 ASSERT_STREQ(member_name(btf, &members[0]), "ent", "field0 name"); 125 ASSERT_STREQ(member_name(btf, &members[1]), "pid", "field1 name"); 126 ASSERT_STREQ(member_name(btf, &members[2]), "comm", "field2 name"); 127 ASSERT_STREQ(member_name(btf, &members[3]), "off", "field3 name"); 128 ASSERT_STREQ(member_name(btf, &members[4]), "len", "field4 name"); 129 out: 130 btf__free(btf); 131 btf__free(vmlinux_btf); 132 } 133