From mboxrd@z Thu Jan 1 00:00:00 1970 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 40B7C4400 for ; Tue, 20 Jun 2023 08:38:02 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 934AFC433C8; Tue, 20 Jun 2023 08:37:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1687250282; bh=uO+8Th2NqoNTdu0300lnGgBvDFBT0ANoSG5DGFrGOcg=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=t1HQzxPmS9cbji+aj9d/KLmEhOTFpBwssEb8nBl19RirOsioX7To2cQPNX39QWkb+ FrT3WMrgzqtqHtgWjWQmoFNoL4EHRRTf6otiRw88WT18a+iQMU2QE++QdSGIqlXybM BG/JNuw6M6FHHnf6ndq4QGbBjHr0wjvhnj3QvbiC3qKIMb0sfm78FmQrgv3AKYX2+N rUgVKzl2QSOVuRJoRl6wpxAbR7R5Va9AoEgjn1Tb0/1IXKKrWcFx5xDdpywx62d6J4 nxs6ncBODDil4d4/8BBZ/Ttx5GrpI7wIq3+5SbzAUzDtznCvcGr37OXVNO1UZiyyrf xg2bxmCMwuOqA== From: Jiri Olsa To: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko Cc: bpf@vger.kernel.org, Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , Stanislav Fomichev , Hao Luo Subject: [PATCHv2 bpf-next 13/24] libbpf: Add uprobe multi link detection Date: Tue, 20 Jun 2023 10:35:39 +0200 Message-ID: <20230620083550.690426-14-jolsa@kernel.org> X-Mailer: git-send-email 2.41.0 In-Reply-To: <20230620083550.690426-1-jolsa@kernel.org> References: <20230620083550.690426-1-jolsa@kernel.org> Precedence: bulk X-Mailing-List: bpf@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Adding uprobe-multi link detection. It will be used later in bpf_program__attach_usdt function to check and use uprobe_multi link over standard uprobe links. Signed-off-by: Jiri Olsa --- tools/lib/bpf/libbpf.c | 29 +++++++++++++++++++++++++++++ tools/lib/bpf/libbpf_internal.h | 2 ++ 2 files changed, 31 insertions(+) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index e42080258ec7..3d570898459e 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -4815,6 +4815,32 @@ static int probe_perf_link(void) return link_fd < 0 && err == -EBADF; } +static int probe_uprobe_multi_link(void) +{ + struct bpf_insn insns[] = { + BPF_MOV64_IMM(BPF_REG_0, 0), + BPF_EXIT_INSN(), + }; + int prog_fd, link_fd, err; + + prog_fd = bpf_prog_load(BPF_PROG_TYPE_KPROBE, NULL, "GPL", + insns, ARRAY_SIZE(insns), NULL); + if (prog_fd < 0) + return -errno; + + /* No need to specify attach function. If the link is not supported + * we will get -EOPNOTSUPP error before any other check is performed. + */ + link_fd = bpf_link_create(prog_fd, -1, BPF_TRACE_UPROBE_MULTI, NULL); + err = -errno; /* close() can clobber errno */ + + if (link_fd >= 0) + close(link_fd); + close(prog_fd); + + return link_fd < 0 && err != -EOPNOTSUPP; +} + static int probe_kern_bpf_cookie(void) { struct bpf_insn insns[] = { @@ -4911,6 +4937,9 @@ static struct kern_feature_desc { [FEAT_SYSCALL_WRAPPER] = { "Kernel using syscall wrapper", probe_kern_syscall_wrapper, }, + [FEAT_UPROBE_LINK] = { + "BPF uprobe multi link support", probe_uprobe_multi_link, + }, }; bool kernel_supports(const struct bpf_object *obj, enum kern_feature_id feat_id) diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h index 22b0834e7fe1..a257eb81af25 100644 --- a/tools/lib/bpf/libbpf_internal.h +++ b/tools/lib/bpf/libbpf_internal.h @@ -354,6 +354,8 @@ enum kern_feature_id { FEAT_BTF_ENUM64, /* Kernel uses syscall wrapper (CONFIG_ARCH_HAS_SYSCALL_WRAPPER) */ FEAT_SYSCALL_WRAPPER, + /* BPF uprobe_multi link support */ + FEAT_UPROBE_LINK, __FEAT_CNT, }; -- 2.41.0