From patchwork Tue May 7 13:19:35 2024 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Benjamin Tissoires X-Patchwork-Id: 795939 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 2E1F31C9EA4; Tue, 7 May 2024 13:20:10 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715088010; cv=none; b=aZW7AEDSYXH6b5yod1LKODtwyOTircouDRb1IrlxFq2DMfGLWr6ffCr/hGnPvdUI+uKnm5nyOxSsy5XBv6d6CtZAeaMaGN9V3Yzyljz5iOkQVWP2D8HMPkw/m8Eqi7VsvmpWGprr/cVEUIKTMCiKkVFT2iF58KPhRNCzHcon49w= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1715088010; c=relaxed/simple; bh=egkWOz43eHGtMFIY140aoiyLqrnrPqlvPykxlJaPgaY=; h=From:Date:Subject:MIME-Version:Content-Type:Message-Id:References: In-Reply-To:To:Cc; b=HcnZ+D7f296qmkbIU5CFTt/j48rNB8VUILummu1r9VhraVf7kTvH8h+IN45v5aDxGPgWd6wghxgdrWroMT8DHKeRL4fNgHzkjWjX9r6OYFR2cPqFuWiVj3qn9/04+d4Sx2We7+sJawAo0OjzhWMEexkHiZzgdPgKbwcyA8lIGBQ= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=KNcm/+Xy; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="KNcm/+Xy" Received: by smtp.kernel.org (Postfix) with ESMTPSA id C210FC4DDE8; Tue, 7 May 2024 13:20:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1715088010; bh=egkWOz43eHGtMFIY140aoiyLqrnrPqlvPykxlJaPgaY=; h=From:Date:Subject:References:In-Reply-To:To:Cc:From; b=KNcm/+XyBrTLdm7oRT16OCMb3/Ap+qDbmQqv+Rp6gUHxh5DyiIXAwUGp2BmaDz7v0 durzb7hgX0XX+Nagbwdc9gc+66y4/uLfnF0/0fFcEAMppdNqi6oySRmeC29LEjggyb M+a84qUFh/pFTcKg14xZ65dTwyNT7YqY75ParDTdk0D6536ARVspSebS5ZBBsMWCWo M9x8b6yREDX4te0TwoMkIEoyRSBSLAioBYFubWsR5n0k4pZiSnWw+69JC6Uta3fFg2 mbhPoXK6Gm7sGdV7Jm15JdEC2pPof9EmHUeZPd3sQjj2xruBqjOHal8cNcHyLSJOcP 8vzR0dIEyJJkQ== From: Benjamin Tissoires Date: Tue, 07 May 2024 15:19:35 +0200 Subject: [PATCH RFC bpf-next 7/8] bpf: implement __aux kfunc argument suffix to fetch prog_aux Precedence: bulk X-Mailing-List: linux-kselftest@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Message-Id: <20240507-bpf_async-v1-7-b4df966096d8@kernel.org> References: <20240507-bpf_async-v1-0-b4df966096d8@kernel.org> In-Reply-To: <20240507-bpf_async-v1-0-b4df966096d8@kernel.org> To: Alexei Starovoitov , Daniel Borkmann , John Fastabend , Andrii Nakryiko , Martin KaFai Lau , Eduard Zingerman , Song Liu , Yonghong Song , KP Singh , Stanislav Fomichev , Hao Luo , Jiri Olsa , Mykola Lysenko , Shuah Khan Cc: bpf@vger.kernel.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, Benjamin Tissoires X-Mailer: b4 0.12.4 X-Developer-Signature: v=1; a=ed25519-sha256; t=1715087980; l=2673; i=bentiss@kernel.org; s=20230215; h=from:subject:message-id; bh=egkWOz43eHGtMFIY140aoiyLqrnrPqlvPykxlJaPgaY=; b=oJAmtA0r9hCIs8UUHfZHyxXeyHI1ooXguBzR9uFMgWiwn0xOIIL26fN4pkiWwxNCGDAFC1RfH wIqjJqkgIp0DKjQK28Gx8oOq7x3Y3Ne4Ttm9fOagKbeixtvtfxJxGGc X-Developer-Key: i=bentiss@kernel.org; a=ed25519; pk=7D1DyAVh6ajCkuUTudt/chMuXWIJHlv2qCsRkIizvFw= This allows kfunc to request the prog_aux environment in their implementation, to have access to the originated bpf_prog for example. Signed-off-by: Benjamin Tissoires --- This is an RFC, and is not meant to be fully reviewed/applied as it is. I'm posting this to show what I wanted to explain in https://lore.kernel.org/bpf/mhkzkf4e23uvljtmwizwcxyuyat2tmfxn33xb4t7waafgmsa66@mcrzpj3b6ssx/ --- kernel/bpf/verifier.c | 40 +++++++++++++++++++++++++++++++++++++++- 1 file changed, 39 insertions(+), 1 deletion(-) diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index 6fba9e2caa83..33b108db0025 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -10909,6 +10909,11 @@ static bool is_kfunc_arg_sleepable_async_cb(const struct btf *btf, const struct return btf_param_match_suffix(btf, arg, "__s_async"); } +static bool is_kfunc_arg_prog_aux(const struct btf *btf, const struct btf_param *arg) +{ + return btf_param_match_suffix(btf, arg, "__aux"); +} + static bool is_kfunc_arg_scalar_with_name(const struct btf *btf, const struct btf_param *arg, const char *name) @@ -11807,7 +11812,8 @@ static int check_kfunc_args(struct bpf_verifier_env *env, struct bpf_kfunc_call_ t = btf_type_skip_modifiers(btf, args[i].type, NULL); - if (is_kfunc_arg_ignore(btf, &args[i])) + if (is_kfunc_arg_ignore(btf, &args[i]) || + is_kfunc_arg_prog_aux(btf, &args[i])) continue; if (btf_type_is_scalar(t)) { @@ -19950,6 +19956,38 @@ static int fixup_kfunc_call(struct bpf_verifier_env *env, struct bpf_insn *insn, insn_buf[1] = ld_addrs[1]; insn_buf[2] = *insn; *cnt = 3; + } else { + struct bpf_kfunc_call_arg_meta meta; + struct bpf_insn kfunc_insn = *insn; + const struct btf_param *args; + u32 i, nargs, prog_aux_arg; + const char *func_name; + int ret; + + /* imm might not have func_id, so create a fake insn with the expected args */ + kfunc_insn.imm = desc->func_id; + + ret = fetch_kfunc_meta(env, &kfunc_insn, &meta, &func_name); + if (ret == 0) { + args = (const struct btf_param *)(meta.func_proto + 1); + nargs = btf_type_vlen(meta.func_proto); + prog_aux_arg = nargs; + + for (i = 0; i < nargs; i++) { + if (is_kfunc_arg_prog_aux(meta.btf, &args[i])) + prog_aux_arg = i; + } + + if (prog_aux_arg < nargs) { + struct bpf_insn ld_addrs[2] = { BPF_LD_IMM64(BPF_REG_1 + prog_aux_arg, + (long)env->prog->aux) }; + + insn_buf[0] = ld_addrs[0]; + insn_buf[1] = ld_addrs[1]; + insn_buf[2] = *insn; + *cnt = 3; + } + } } return 0; }