Commit 95226f5a authored by Andrii Nakryiko's avatar Andrii Nakryiko Committed by Alexei Starovoitov
Browse files

selftests/bpf: add __arg_ctx BTF rewrite test 



Add a test validating that libbpf uploads BTF and func_info with
rewritten type information for arguments of global subprogs that are
marked with __arg_ctx tag.

Suggested-by: default avatarEduard Zingerman <eddyz87@gmail.com>
Signed-off-by: default avatarAndrii Nakryiko <andrii@kernel.org>
Link: https://lore.kernel.org/r/20240104013847.3875810-10-andrii@kernel.org


Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
parent 67fe4591

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

+106 −0
Original line number Diff line number Diff line
@@ -20,6 +20,109 @@ 
#include "test_global_func17.skel.h"

#include "test_global_func_ctx_args.skel.h"



#include "bpf/libbpf_internal.h"

#include "btf_helpers.h"



static void check_ctx_arg_type(const struct btf *btf, const struct btf_param *p)

{

	const struct btf_type *t;

	const char *s;



	t = btf__type_by_id(btf, p->type);

	if (!ASSERT_EQ(btf_kind(t), BTF_KIND_PTR, "ptr_t"))

		return;



	s = btf_type_raw_dump(btf, t->type);

	if (!ASSERT_HAS_SUBSTR(s, "STRUCT 'bpf_perf_event_data' size=0 vlen=0",

			       "ctx_struct_t"))

		return;

}



static void subtest_ctx_arg_rewrite(void)

{

	struct test_global_func_ctx_args *skel = NULL;

	struct bpf_prog_info info;

	char func_info_buf[1024] __attribute__((aligned(8)));

	struct bpf_func_info_min *rec;

	struct btf *btf = NULL;

	__u32 info_len = sizeof(info);

	int err, fd, i;



	skel = test_global_func_ctx_args__open();

	if (!ASSERT_OK_PTR(skel, "skel_open"))

		return;



	bpf_program__set_autoload(skel->progs.arg_tag_ctx_perf, true);



	err = test_global_func_ctx_args__load(skel);

	if (!ASSERT_OK(err, "skel_load"))

		goto out;



	memset(&info, 0, sizeof(info));

	info.func_info = ptr_to_u64(&func_info_buf);

	info.nr_func_info = 3;

	info.func_info_rec_size = sizeof(struct bpf_func_info_min);



	fd = bpf_program__fd(skel->progs.arg_tag_ctx_perf);

	err = bpf_prog_get_info_by_fd(fd, &info, &info_len);

	if (!ASSERT_OK(err, "prog_info"))

		goto out;



	if (!ASSERT_EQ(info.nr_func_info, 3, "nr_func_info"))

		goto out;



	btf = btf__load_from_kernel_by_id(info.btf_id);

	if (!ASSERT_OK_PTR(btf, "obj_kern_btf"))

		goto out;



	rec = (struct bpf_func_info_min *)func_info_buf;

	for (i = 0; i < info.nr_func_info; i++, rec = (void *)rec + info.func_info_rec_size) {

		const struct btf_type *fn_t, *proto_t;

		const char *name;



		if (rec->insn_off == 0)

			continue; /* main prog, skip */



		fn_t = btf__type_by_id(btf, rec->type_id);

		if (!ASSERT_OK_PTR(fn_t, "fn_type"))

			goto out;

		if (!ASSERT_EQ(btf_kind(fn_t), BTF_KIND_FUNC, "fn_type_kind"))

			goto out;

		proto_t = btf__type_by_id(btf, fn_t->type);

		if (!ASSERT_OK_PTR(proto_t, "proto_type"))

			goto out;



		name = btf__name_by_offset(btf, fn_t->name_off);

		if (strcmp(name, "subprog_ctx_tag") == 0) {

			/* int subprog_ctx_tag(void *ctx __arg_ctx) */

			if (!ASSERT_EQ(btf_vlen(proto_t), 1, "arg_cnt"))

				goto out;



			/* arg 0 is PTR -> STRUCT bpf_perf_event_data */

			check_ctx_arg_type(btf, &btf_params(proto_t)[0]);

		} else if (strcmp(name, "subprog_multi_ctx_tags") == 0) {

			/* int subprog_multi_ctx_tags(void *ctx1 __arg_ctx,

			 *			      struct my_struct *mem,

			 *			      void *ctx2 __arg_ctx)

			 */

			if (!ASSERT_EQ(btf_vlen(proto_t), 3, "arg_cnt"))

				goto out;



			/* arg 0 is PTR -> STRUCT bpf_perf_event_data */

			check_ctx_arg_type(btf, &btf_params(proto_t)[0]);

			/* arg 2 is PTR -> STRUCT bpf_perf_event_data */

			check_ctx_arg_type(btf, &btf_params(proto_t)[2]);

		} else {

			ASSERT_FAIL("unexpected subprog %s", name);

			goto out;

		}

	}



out:

	btf__free(btf);

	test_global_func_ctx_args__destroy(skel);

}



void test_test_global_funcs(void)

{

	RUN_TESTS(test_global_func1);
@@ -40,4 +143,7 @@ void test_test_global_funcs(void) 
	RUN_TESTS(test_global_func16);

	RUN_TESTS(test_global_func17);

	RUN_TESTS(test_global_func_ctx_args);



	if (test__start_subtest("ctx_arg_rewrite"))

		subtest_ctx_arg_rewrite();

}