selftests/bpf: add test for BTF-defined maps

Add file test for BTF-defined map definition.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
Acked-by: Song Liu <songliubraving@fb.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>

tools/testing/selftests/bpf/progs/test_btf_newkv.c

+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (c) 2018 Facebook */
+#include <linux/bpf.h>
+#include "bpf_helpers.h"
+
+int _version SEC("version") = 1;
+
+struct ipv_counts {
+	unsigned int v4;
+	unsigned int v6;
+};
+
+/* just to validate we can handle maps in multiple sections */
+struct bpf_map_def SEC("maps") btf_map_legacy = {
+	.type = BPF_MAP_TYPE_ARRAY,
+	.key_size = sizeof(int),
+	.value_size = sizeof(long long),
+	.max_entries = 4,
+};
+
+BPF_ANNOTATE_KV_PAIR(btf_map_legacy, int, struct ipv_counts);
+
+struct {
+	int *key;
+	struct ipv_counts *value;
+	unsigned int type;
+	unsigned int max_entries;
+} btf_map SEC(".maps") = {
+	.type = BPF_MAP_TYPE_ARRAY,
+	.max_entries = 4,
+};
+
+struct dummy_tracepoint_args {
+	unsigned long long pad;
+	struct sock *sock;
+};
+
+__attribute__((noinline))
+static int test_long_fname_2(struct dummy_tracepoint_args *arg)
+{
+	struct ipv_counts *counts;
+	int key = 0;
+
+	if (!arg->sock)
+		return 0;
+
+	counts = bpf_map_lookup_elem(&btf_map, &key);
+	if (!counts)
+		return 0;
+
+	counts->v6++;
+
+	/* just verify we can reference both maps */
+	counts = bpf_map_lookup_elem(&btf_map_legacy, &key);
+	if (!counts)
+		return 0;
+
+	return 0;
+}
+
+__attribute__((noinline))
+static int test_long_fname_1(struct dummy_tracepoint_args *arg)
+{
+	return test_long_fname_2(arg);
+}
+
+SEC("dummy_tracepoint")
+int _dummy_tracepoint(struct dummy_tracepoint_args *arg)
+{
+	return test_long_fname_1(arg);
+}
+
+char _license[] SEC("license") = "GPL";

tools/testing/selftests/bpf/test_btf.c

@@ -4016,13 +4016,9 @@ struct btf_file_test {
 };
 
 static struct btf_file_test file_tests[] = {
-{
-	.file = "test_btf_haskv.o",
-},
-{
-	.file = "test_btf_nokv.o",
-	.btf_kv_notfound = true,
-},
+	{ .file = "test_btf_haskv.o", },
+	{ .file = "test_btf_newkv.o", },
+	{ .file = "test_btf_nokv.o", .btf_kv_notfound = true, },
 };
 
 static int do_test_file(unsigned int test_num)