Merge branch 'Support static initialization of BPF_MAP_TYPE_PROG_ARRAY'

Hengqi Chen says:

====================

Make libbpf support static initialization of BPF_MAP_TYPE_PROG_ARRAY
with a syntax similar to map-in-map initialization:

    SEC("socket")
    int tailcall_1(void *ctx)
    {
        return 0;
    }

    struct {
        __uint(type, BPF_MAP_TYPE_PROG_ARRAY);
        __uint(max_entries, 2);
        __uint(key_size, sizeof(__u32));
        __array(values, int (void *));
    } prog_array_init SEC(".maps") = {
        .values = {
            [1] = (void *)&tailcall_1,
        },
    };

v1->v2:
  - Add stricter checks on relos collect, some renamings (Andrii)
  - Update selftest to check tailcall result (Andrii)
====================

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>

1 files changed, 32 insertions, 0 deletions

diff --git a/tools/testing/selftests/bpf/prog_tests/prog_array_init.c b/tools/testing/selftests/bpf/prog_tests/prog_array_init.c
new file mode 100644
index 000000000000..fc4657619739
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/prog_array_init.c
@@ -0,0 +1,32 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Copyright (c) 2021 Hengqi Chen */
+
+#include <test_progs.h>
+#include "test_prog_array_init.skel.h"
+
+void test_prog_array_init(void)
+{
+	struct test_prog_array_init *skel;
+	int err;
+
+	skel = test_prog_array_init__open();
+	if (!ASSERT_OK_PTR(skel, "could not open BPF object"))
+		return;
+
+	skel->rodata->my_pid = getpid();
+
+	err = test_prog_array_init__load(skel);
+	if (!ASSERT_OK(err, "could not load BPF object"))
+		goto cleanup;
+
+	skel->links.entry = bpf_program__attach_raw_tracepoint(skel->progs.entry, "sys_enter");
+	if (!ASSERT_OK_PTR(skel->links.entry, "could not attach BPF program"))
+		goto cleanup;
+
+	usleep(1);
+
+	ASSERT_EQ(skel->bss->value, 42, "unexpected value");
+
+cleanup:
+	test_prog_array_init__destroy(skel);
+}