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From:   Benjamin Tissoires <benjamin.tissoires@redhat.com>
To:     Greg KH <gregkh@linuxfoundation.org>,
        Jiri Kosina <jikos@kernel.org>,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>,
        Martin KaFai Lau <kafai@fb.com>,
        Song Liu <songliubraving@fb.com>, Yonghong Song <yhs@fb.com>,
        John Fastabend <john.fastabend@gmail.com>,
        KP Singh <kpsingh@kernel.org>, Shuah Khan <shuah@kernel.org>,
        Dave Marchevsky <davemarchevsky@fb.com>,
        Joe Stringer <joe@cilium.io>, Jonathan Corbet <corbet@lwn.net>
Cc:     Tero Kristo <tero.kristo@linux.intel.com>,
        linux-kernel@vger.kernel.org, linux-input@vger.kernel.org,
        netdev@vger.kernel.org, bpf@vger.kernel.org,
        linux-kselftest@vger.kernel.org, linux-doc@vger.kernel.org,
        Benjamin Tissoires <benjamin.tissoires@redhat.com>
Subject: [PATCH bpf-next v5 01/17] bpf/btf: also allow kfunc in tracing and syscall programs
Date:   Wed, 18 May 2022 22:59:08 +0200
Message-Id: <20220518205924.399291-2-benjamin.tissoires@redhat.com>
In-Reply-To: <20220518205924.399291-1-benjamin.tissoires@redhat.com>
References: <20220518205924.399291-1-benjamin.tissoires@redhat.com>
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Tracing and syscall BPF program types are very convenient to add BPF
capabilities to subsystem otherwise not BPF capable.
When we add kfuncs capabilities to those program types, we can add
BPF features to subsystems without having to touch BPF core.

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>

---

changes in v5:
- also add syscalls

new in v4:
- I think this is where I need to add my new kfuncs, though
  in the end I need to be able to change the incoming data, so
  maybe only fmod_ret is the one we need to be able to be RW.
---
 kernel/bpf/btf.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index 2f0b0440131c..7bccaa4646e5 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -202,6 +202,8 @@ enum btf_kfunc_hook {
 	BTF_KFUNC_HOOK_XDP,
 	BTF_KFUNC_HOOK_TC,
 	BTF_KFUNC_HOOK_STRUCT_OPS,
+	BTF_KFUNC_HOOK_TRACING,
+	BTF_KFUNC_HOOK_SYSCALL,
 	BTF_KFUNC_HOOK_MAX,
 };
 
@@ -7110,6 +7112,10 @@ static int bpf_prog_type_to_kfunc_hook(enum bpf_prog_type prog_type)
 		return BTF_KFUNC_HOOK_TC;
 	case BPF_PROG_TYPE_STRUCT_OPS:
 		return BTF_KFUNC_HOOK_STRUCT_OPS;
+	case BPF_PROG_TYPE_TRACING:
+		return BTF_KFUNC_HOOK_TRACING;
+	case BPF_PROG_TYPE_SYSCALL:
+		return BTF_KFUNC_HOOK_SYSCALL;
 	default:
 		return BTF_KFUNC_HOOK_MAX;
 	}
-- 
2.36.1