From patchwork Wed Jul 14 14:15:32 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Quentin Monnet X-Patchwork-Id: 477287 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 923FAC07E9A for ; Wed, 14 Jul 2021 14:15:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7AAAC61183 for ; Wed, 14 Jul 2021 14:15:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239490AbhGNOSu (ORCPT ); Wed, 14 Jul 2021 10:18:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:57918 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239449AbhGNOSo (ORCPT ); Wed, 14 Jul 2021 10:18:44 -0400 Received: from mail-wm1-x335.google.com (mail-wm1-x335.google.com [IPv6:2a00:1450:4864:20::335]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id ACEAEC061762 for ; Wed, 14 Jul 2021 07:15:52 -0700 (PDT) Received: by mail-wm1-x335.google.com with SMTP id y21-20020a7bc1950000b02902161fccabf1so4020876wmi.2 for ; Wed, 14 Jul 2021 07:15:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=isovalent-com.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=mUCBpk5CyiIy6Bvb2NbvqDJflK7m0z2f3UFX/XqbowU=; b=RAYn8/FyE0vDqn1+um4/dz8OvsCxr3xK8V0y/cH7AFK8aH+gE18yp3X0EcDEfpSPoc KTky/k9y28lPJmzcxhzKgAi8aJUsdbOLvGAVl6MnEMEB1Btovt0aGlKZYMQBXsQHVG2g Q/zTCmD1iytWlKFNoCsm0zOzBxqDLR88Z0uZJmWdxCMK+DujzcTCA566SpjqTBHxUqsI cKHXwn97FRXHi7+T4zBYII3biel0jV0TizP04thyvHsHeGWuctfdMr5pCJOdWamJgwn1 wntfJYFam8/DLeKRtRtpk94h3nbCDC9ehAQvzAB3RctJBt/znjQPu3nKlErKEi7mvDq7 4cFA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=mUCBpk5CyiIy6Bvb2NbvqDJflK7m0z2f3UFX/XqbowU=; b=F0dKDRUHyp01cGjVz3sVq+MTn1ZTzVahG4DhyDUG5U3a/ktW/KOCo72Ksl22HQpyBB GaCtHkmhdBOzZbAfZwuXLpGWWM3WqfGexjIV0n6JGVuCq7+4YnnmS/xW1H1DvjhE5oLS RR2DGQAYpVwAo39Nn9S+fsjvGTNwukunIgUYWgsdjp2jPHjp6XQlPWN0F8QMrjSfzmZN 1CiU6ETjspd6eLYy5cL70y+OlUuIxiJdJu4e/yrA1etEWggcBVwY7K9PMjEsnrhol2P3 4Lc+rZToVOpIsqinWgyLaf2X53bKBD/oaMv1NhQlZ+sl7eSOTj4/lD2Tt+rm2hj2w3A4 Jm3Q== X-Gm-Message-State: AOAM531kMPcxhGzvBCcgJMPRPvD0FHl4/wB7EulwdifNaTwwsvTqj4aS A0b8O7RkOiEEw4FpPsYskpruCqoJNMisEA== X-Google-Smtp-Source: ABdhPJyj3j4nBjWxbdPwSLusLHVQgftz8JotKj/8bOPJqJh0mVBKnenv5b0+bmlA5F65Nne5T1f5vA== X-Received: by 2002:a7b:c147:: with SMTP id z7mr2175067wmi.110.1626272151231; Wed, 14 Jul 2021 07:15:51 -0700 (PDT) Received: from localhost.localdomain ([149.86.90.174]) by smtp.gmail.com with ESMTPSA id a207sm6380037wme.27.2021.07.14.07.15.50 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 14 Jul 2021 07:15:50 -0700 (PDT) From: Quentin Monnet To: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko Cc: netdev@vger.kernel.org, bpf@vger.kernel.org, Quentin Monnet Subject: [PATCH bpf-next 6/6] tools: bpftool: support dumping split BTF by id Date: Wed, 14 Jul 2021 15:15:32 +0100 Message-Id: <20210714141532.28526-7-quentin@isovalent.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210714141532.28526-1-quentin@isovalent.com> References: <20210714141532.28526-1-quentin@isovalent.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Split BTF objects are typically BTF objects for kernel modules, which are incrementally built on top of kernel BTF instead of redefining all kernel symbols they need. We can use bpftool with its -B command-line option to dump split BTF objects. It works well when the handle provided for the BTF object to dump is a "path" to the BTF object, typically under /sys/kernel/btf, because bpftool internally calls btf__parse_split() which can take a "base_btf" pointer and resolve the BTF reconstruction (although in that case, the "-B" option is unnecessary because bpftool performs autodetection). However, it did not work so far when passing the BTF object through its id, because bpftool would call btf__get_from_id() which did not provide a way to pass a "base_btf" pointer. In other words, the following works: # bpftool btf dump file /sys/kernel/btf/i2c_smbus -B /sys/kernel/btf/vmlinux But this was not possible: # bpftool btf dump id 6 -B /sys/kernel/btf/vmlinux The libbpf API has recently changed, and btf__get_from_id() has been deprecated in favour of btf__load_from_kernel_by_id() and its version with support for split BTF, btf__load_from_kernel_by_id_split(). Let's update bpftool to make it able to dump the BTF object in the second case as well. Signed-off-by: Quentin Monnet --- tools/bpf/bpftool/btf.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/tools/bpf/bpftool/btf.c b/tools/bpf/bpftool/btf.c index 2296e8eba0ff..b77a59225f5b 100644 --- a/tools/bpf/bpftool/btf.c +++ b/tools/bpf/bpftool/btf.c @@ -580,7 +580,7 @@ static int do_dump(int argc, char **argv) } if (!btf) { - err = btf__load_from_kernel_by_id(btf_id, &btf); + err = btf__load_from_kernel_by_id_split(btf_id, &btf, base_btf); if (err) { p_err("get btf by id (%u): %s", btf_id, strerror(err)); goto done;