bpf: selftests: Add selftests for module kfunc support

This adds selftests that tests the success and failure path for modules
kfuncs (in presence of invalid kfunc calls) for both libbpf and
gen_loader. It also adds a prog_test kfunc_btf_id_list so that we can
add module BTF ID set from bpf_testmod.

This also introduces  a couple of test cases to verifier selftests for
validating whether we get an error or not depending on if invalid kfunc
call remains after elimination of unreachable instructions.

Signed-off-by: Kumar Kartikeya Dwivedi <memxor@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20211002011757.311265-10-memxor@gmail.com

1 files changed, 28 insertions, 0 deletions

diff --git a/tools/testing/selftests/bpf/prog_tests/ksyms_module_libbpf.c b/tools/testing/selftests/bpf/prog_tests/ksyms_module_libbpf.c
new file mode 100644
index 000000000000..e6343ef63af9
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/ksyms_module_libbpf.c
@@ -0,0 +1,28 @@
+// SPDX-License-Identifier: GPL-2.0
+
+#include <test_progs.h>
+#include <network_helpers.h>
+#include "test_ksyms_module.skel.h"
+
+void test_ksyms_module_libbpf(void)
+{
+	struct test_ksyms_module *skel;
+	int retval, err;
+
+	if (!env.has_testmod) {
+		test__skip();
+		return;
+	}
+
+	skel = test_ksyms_module__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "test_ksyms_module__open"))
+		return;
+	err = bpf_prog_test_run(bpf_program__fd(skel->progs.load), 1, &pkt_v4,
+				sizeof(pkt_v4), NULL, NULL, (__u32 *)&retval, NULL);
+	if (!ASSERT_OK(err, "bpf_prog_test_run"))
+		goto cleanup;
+	ASSERT_EQ(retval, 0, "retval");
+	ASSERT_EQ(skel->bss->out_bpf_testmod_ksym, 42, "bpf_testmod_ksym");
+cleanup:
+	test_ksyms_module__destroy(skel);
+}