From patchwork Wed Sep 7 15:45:10 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jesper Dangaard Brouer X-Patchwork-Id: 12969155 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id E4ABAC54EE9 for ; Wed, 7 Sep 2022 15:45:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229604AbiIGPpV (ORCPT ); Wed, 7 Sep 2022 11:45:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:47160 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229544AbiIGPpQ (ORCPT ); Wed, 7 Sep 2022 11:45:16 -0400 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1EC101705E for ; Wed, 7 Sep 2022 08:45:15 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1662565514; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=CfnpNVOn8bVeC3t2vM1lmC87z9StKK7QVfzUjHELd7M=; b=XnKGPbzVvTT+4J1dn0uLjBKdQxdsZFbQ0Wy3tM3khtycn15FMC7twSOzhS+VBCErDrZtGD kUVpvsiLXjwtgONM2+7js5m0raT34KBYG4lb2Aswk97S8rs4qqnxrScl+Lt4QzDgfAgDhu AqeInseJI3BNWWRUFbdiwudE+IkZYMg= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-449-uTG5rkmhOmSngS_6zY5Nxw-1; Wed, 07 Sep 2022 11:45:12 -0400 X-MC-Unique: uTG5rkmhOmSngS_6zY5Nxw-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 0102B801231; Wed, 7 Sep 2022 15:45:12 +0000 (UTC) Received: from firesoul.localdomain (unknown [10.40.208.22]) by smtp.corp.redhat.com (Postfix) with ESMTP id B623290A04; Wed, 7 Sep 2022 15:45:11 +0000 (UTC) Received: from [192.168.42.3] (localhost [IPv6:::1]) by firesoul.localdomain (Postfix) with ESMTP id BC87230721A6C; Wed, 7 Sep 2022 17:45:10 +0200 (CEST) Subject: [PATCH RFCv2 bpf-next 02/18] libbpf: try to load vmlinux BTF from the kernel first From: Jesper Dangaard Brouer To: bpf@vger.kernel.org Cc: Jesper Dangaard Brouer , netdev@vger.kernel.org, xdp-hints@xdp-project.net, larysa.zaremba@intel.com, memxor@gmail.com, Lorenzo Bianconi , mtahhan@redhat.com, Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , dave@dtucker.co.uk, Magnus Karlsson , bjorn@kernel.org Date: Wed, 07 Sep 2022 17:45:10 +0200 Message-ID: <166256551073.1434226.11702276674514019182.stgit@firesoul> In-Reply-To: <166256538687.1434226.15760041133601409770.stgit@firesoul> References: <166256538687.1434226.15760041133601409770.stgit@firesoul> User-Agent: StGit/1.4 MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.11.54.5 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net X-Patchwork-State: RFC From: Larysa Zaremba Try to acquire vmlinux BTF the same way it's being done for module BTFs. Use btf_load_next_with_info() and resort to the filesystem lookup only if it fails. Also, adjust debug messages in btf__load_vmlinux_btf() to reflect that it actually tries to load vmlinux BTF. Signed-off-by: Larysa Zaremba Signed-off-by: Alexander Lobakin --- tools/lib/bpf/btf.c | 32 ++++++++++++++++++++++++++++++-- 1 file changed, 30 insertions(+), 2 deletions(-) diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index cad11c56cf1f..1fd12a2e1b08 100644 --- a/tools/lib/bpf/btf.c +++ b/tools/lib/bpf/btf.c @@ -4744,6 +4744,25 @@ struct btf *btf_load_next_with_info(__u32 start_id, struct bpf_btf_info *info, } } +static struct btf *btf_load_vmlinux_from_kernel(void) +{ + char name[BTF_NAME_BUF_LEN] = { }; + struct bpf_btf_info info; + struct btf *btf; + + memset(&info, 0, sizeof(info)); + info.name = ptr_to_u64(name); + info.name_len = sizeof(name); + + btf = btf_load_next_with_info(0, &info, NULL, true); + if (!libbpf_get_error(btf)) { + close(btf->fd); + btf__set_fd(btf, -1); + } + + return btf; +} + /* * Probe few well-known locations for vmlinux kernel image and try to load BTF * data out of it to use for target BTF. @@ -4770,6 +4789,15 @@ struct btf *btf__load_vmlinux_btf(void) struct btf *btf; int i, err; + btf = btf_load_vmlinux_from_kernel(); + err = libbpf_get_error(btf); + pr_debug("loading vmlinux BTF from kernel: %d\n", err); + if (!err) + return btf; + + pr_info("failed to load vmlinux BTF from kernel: %d, will look through filesystem\n", + err); + uname(&buf); for (i = 0; i < ARRAY_SIZE(locations); i++) { @@ -4783,14 +4811,14 @@ struct btf *btf__load_vmlinux_btf(void) else btf = btf__parse_elf(path, NULL); err = libbpf_get_error(btf); - pr_debug("loading kernel BTF '%s': %d\n", path, err); + pr_debug("loading vmlinux BTF '%s': %d\n", path, err); if (err) continue; return btf; } - pr_warn("failed to find valid kernel BTF\n"); + pr_warn("failed to find valid vmlinux BTF\n"); return libbpf_err_ptr(-ESRCH); }