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From: Ihor Solodrai <ihor.solodrai@linux.dev>
To: Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Andrii Nakryiko <andrii@kernel.org>,
	Martin KaFai Lau <martin.lau@linux.dev>,
	Eduard Zingerman <eddyz87@gmail.com>
Cc: Mykyta Yatsenko <yatsenko@meta.com>, Tejun Heo <tj@kernel.org>,
	Alan Maguire <alan.maguire@oracle.com>,
	Benjamin Tissoires <bentiss@kernel.org>,
	Jiri Kosina <jikos@kernel.org>, Amery Hung <ameryhung@gmail.com>,
	bpf@vger.kernel.org, linux-kernel@vger.kernel.org,
	linux-input@vger.kernel.org, sched-ext@lists.linux.dev
Subject: [PATCH bpf-next v2 06/13] selftests/bpf: Add tests for KF_IMPLICIT_ARGS
Date: Fri, 16 Jan 2026 12:16:53 -0800	[thread overview]
Message-ID: <20260116201700.864797-7-ihor.solodrai@linux.dev> (raw)
In-Reply-To: <20260116201700.864797-1-ihor.solodrai@linux.dev>

Add trivial end-to-end tests to validate that KF_IMPLICIT_ARGS flag is
properly handled by both resolve_btfids and the verifier.

Declare kfuncs in bpf_testmod. Check that bpf_prog_aux pointer is set
in the kfunc implementation. Verify that calls with implicit args and
a legacy case all work.

Signed-off-by: Ihor Solodrai <ihor.solodrai@linux.dev>
---
 .../bpf/prog_tests/kfunc_implicit_args.c      | 10 +++++
 .../selftests/bpf/progs/kfunc_implicit_args.c | 41 +++++++++++++++++++
 .../selftests/bpf/test_kmods/bpf_testmod.c    | 26 ++++++++++++
 3 files changed, 77 insertions(+)
 create mode 100644 tools/testing/selftests/bpf/prog_tests/kfunc_implicit_args.c
 create mode 100644 tools/testing/selftests/bpf/progs/kfunc_implicit_args.c

diff --git a/tools/testing/selftests/bpf/prog_tests/kfunc_implicit_args.c b/tools/testing/selftests/bpf/prog_tests/kfunc_implicit_args.c
new file mode 100644
index 000000000000..5e4793c9c29a
--- /dev/null
+++ b/tools/testing/selftests/bpf/prog_tests/kfunc_implicit_args.c
@@ -0,0 +1,10 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2026 Meta Platforms, Inc. and affiliates. */
+
+#include <test_progs.h>
+#include "kfunc_implicit_args.skel.h"
+
+void test_kfunc_implicit_args(void)
+{
+	RUN_TESTS(kfunc_implicit_args);
+}
diff --git a/tools/testing/selftests/bpf/progs/kfunc_implicit_args.c b/tools/testing/selftests/bpf/progs/kfunc_implicit_args.c
new file mode 100644
index 000000000000..89b6a47e22dd
--- /dev/null
+++ b/tools/testing/selftests/bpf/progs/kfunc_implicit_args.c
@@ -0,0 +1,41 @@
+// SPDX-License-Identifier: GPL-2.0
+/* Copyright (c) 2026 Meta Platforms, Inc. and affiliates. */
+
+#include <vmlinux.h>
+#include <bpf/bpf_helpers.h>
+#include "bpf_misc.h"
+
+extern int bpf_kfunc_implicit_arg(int a) __weak __ksym;
+extern int bpf_kfunc_implicit_arg_impl(int a, struct bpf_prog_aux *aux) __weak __ksym; /* illegal */
+extern int bpf_kfunc_implicit_arg_legacy(int a, int b) __weak __ksym;
+extern int bpf_kfunc_implicit_arg_legacy_impl(int a, int b, struct bpf_prog_aux *aux) __weak __ksym;
+
+char _license[] SEC("license") = "GPL";
+
+SEC("syscall")
+__retval(5)
+int test_kfunc_implicit_arg(void *ctx)
+{
+	return bpf_kfunc_implicit_arg(5);
+}
+
+SEC("syscall")
+__failure __msg("cannot find address for kernel function bpf_kfunc_implicit_arg_impl")
+int test_kfunc_implicit_arg_impl_illegal(void *ctx)
+{
+	return bpf_kfunc_implicit_arg_impl(5, NULL);
+}
+
+SEC("syscall")
+__retval(7)
+int test_kfunc_implicit_arg_legacy(void *ctx)
+{
+	return bpf_kfunc_implicit_arg_legacy(3, 4);
+}
+
+SEC("syscall")
+__retval(11)
+int test_kfunc_implicit_arg_legacy_impl(void *ctx)
+{
+	return bpf_kfunc_implicit_arg_legacy_impl(5, 6, NULL);
+}
diff --git a/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c b/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c
index bc07ce9d5477..a996b816ecc4 100644
--- a/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c
+++ b/tools/testing/selftests/bpf/test_kmods/bpf_testmod.c
@@ -1142,6 +1142,10 @@ __bpf_kfunc int bpf_kfunc_st_ops_inc10(struct st_ops_args *args)
 __bpf_kfunc int bpf_kfunc_multi_st_ops_test_1(struct st_ops_args *args, u32 id);
 __bpf_kfunc int bpf_kfunc_multi_st_ops_test_1_impl(struct st_ops_args *args, void *aux_prog);
 
+__bpf_kfunc int bpf_kfunc_implicit_arg(int a, struct bpf_prog_aux *aux);
+__bpf_kfunc int bpf_kfunc_implicit_arg_legacy(int a, int b, struct bpf_prog_aux *aux);
+__bpf_kfunc int bpf_kfunc_implicit_arg_legacy_impl(int a, int b, struct bpf_prog_aux *aux);
+
 BTF_KFUNCS_START(bpf_testmod_check_kfunc_ids)
 BTF_ID_FLAGS(func, bpf_testmod_test_mod_kfunc)
 BTF_ID_FLAGS(func, bpf_kfunc_call_test1)
@@ -1184,6 +1188,9 @@ BTF_ID_FLAGS(func, bpf_kfunc_st_ops_test_pro_epilogue, KF_SLEEPABLE)
 BTF_ID_FLAGS(func, bpf_kfunc_st_ops_inc10)
 BTF_ID_FLAGS(func, bpf_kfunc_multi_st_ops_test_1)
 BTF_ID_FLAGS(func, bpf_kfunc_multi_st_ops_test_1_impl)
+BTF_ID_FLAGS(func, bpf_kfunc_implicit_arg, KF_IMPLICIT_ARGS)
+BTF_ID_FLAGS(func, bpf_kfunc_implicit_arg_legacy, KF_IMPLICIT_ARGS)
+BTF_ID_FLAGS(func, bpf_kfunc_implicit_arg_legacy_impl)
 BTF_KFUNCS_END(bpf_testmod_check_kfunc_ids)
 
 static int bpf_testmod_ops_init(struct btf *btf)
@@ -1675,6 +1682,25 @@ int bpf_kfunc_multi_st_ops_test_1_impl(struct st_ops_args *args, void *aux__prog
 	return ret;
 }
 
+int bpf_kfunc_implicit_arg(int a, struct bpf_prog_aux *aux)
+{
+	if (aux && a > 0)
+		return a;
+	return -EINVAL;
+}
+
+int bpf_kfunc_implicit_arg_legacy(int a, int b, struct bpf_prog_aux *aux)
+{
+	if (aux)
+		return a + b;
+	return -EINVAL;
+}
+
+int bpf_kfunc_implicit_arg_legacy_impl(int a, int b, struct bpf_prog_aux *aux)
+{
+	return bpf_kfunc_implicit_arg_legacy(a, b, aux);
+}
+
 static int multi_st_ops_reg(void *kdata, struct bpf_link *link)
 {
 	struct bpf_testmod_multi_st_ops *st_ops =
-- 
2.52.0


  parent reply	other threads:[~2026-01-16 20:17 UTC|newest]

Thread overview: 35+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2026-01-16 20:16 [PATCH bpf-next v2 00/13] bpf: Kernel functions with KF_IMPLICIT_ARGS Ihor Solodrai
2026-01-16 20:16 ` [PATCH bpf-next v2 01/13] bpf: Refactor btf_kfunc_id_set_contains Ihor Solodrai
2026-01-16 20:16 ` [PATCH bpf-next v2 02/13] bpf: Introduce struct bpf_kfunc_meta Ihor Solodrai
2026-01-16 20:16 ` [PATCH bpf-next v2 03/13] bpf: Verifier support for KF_IMPLICIT_ARGS Ihor Solodrai
2026-01-20  0:03   ` Eduard Zingerman
2026-01-16 20:16 ` [PATCH bpf-next v2 04/13] resolve_btfids: Introduce finalize_btf() step Ihor Solodrai
2026-01-20  0:13   ` Eduard Zingerman
2026-01-20 18:11     ` Ihor Solodrai
2026-01-20 18:19       ` Eduard Zingerman
2026-01-20 18:35         ` Ihor Solodrai
2026-01-20 18:40           ` Eduard Zingerman
2026-01-16 20:16 ` [PATCH bpf-next v2 05/13] resolve_btfids: Support for KF_IMPLICIT_ARGS Ihor Solodrai
2026-01-16 20:39   ` bot+bpf-ci
2026-01-16 20:44     ` Ihor Solodrai
2026-01-17  0:06   ` Andrii Nakryiko
2026-01-17  6:36     ` Ihor Solodrai
2026-01-20  0:24       ` Eduard Zingerman
2026-01-20  0:55   ` Eduard Zingerman
2026-01-16 20:16 ` Ihor Solodrai [this message]
2026-01-20  1:24   ` [PATCH bpf-next v2 06/13] selftests/bpf: Add tests " Eduard Zingerman
2026-01-16 20:16 ` [PATCH bpf-next v2 07/13] bpf: Migrate bpf_wq_set_callback_impl() to KF_IMPLICIT_ARGS Ihor Solodrai
2026-01-20  1:50   ` Eduard Zingerman
2026-01-16 20:16 ` [PATCH bpf-next v2 08/13] HID: Use bpf_wq_set_callback kernel function Ihor Solodrai
2026-01-16 20:16 ` [PATCH bpf-next v2 09/13] bpf: Migrate bpf_task_work_schedule_* kfuncs to KF_IMPLICIT_ARGS Ihor Solodrai
2026-01-20  1:52   ` Eduard Zingerman
2026-01-16 20:16 ` [PATCH bpf-next v2 10/13] bpf: Migrate bpf_stream_vprintk() " Ihor Solodrai
2026-01-20  1:53   ` Eduard Zingerman
2026-01-16 20:16 ` [PATCH bpf-next v2 11/13] selftests/bpf: Migrate struct_ops_assoc test " Ihor Solodrai
2026-01-20  1:59   ` Eduard Zingerman
2026-01-20 18:20     ` Ihor Solodrai
2026-01-20 18:24       ` Eduard Zingerman
2026-01-16 20:16 ` [PATCH bpf-next v2 12/13] bpf: Remove __prog kfunc arg annotation Ihor Solodrai
2026-01-20  2:01   ` Eduard Zingerman
2026-01-16 20:17 ` [PATCH bpf-next v2 13/13] bpf,docs: Document KF_IMPLICIT_ARGS flag Ihor Solodrai
2026-01-20  1:49 ` [PATCH bpf-next v2 00/13] bpf: Kernel functions with KF_IMPLICIT_ARGS Eduard Zingerman

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