From patchwork Mon Jan 18 16:01:39 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Giuliano Procida X-Patchwork-Id: 12027595 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 X-Spam-Level: X-Spam-Status: No, score=-26.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=ham 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 72319C433E0 for ; Mon, 18 Jan 2021 16:03:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 404F722B4E for ; Mon, 18 Jan 2021 16:03:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2405918AbhARQCl (ORCPT ); Mon, 18 Jan 2021 11:02:41 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45812 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2406298AbhARQCg (ORCPT ); Mon, 18 Jan 2021 11:02:36 -0500 Received: from mail-ed1-x54a.google.com (mail-ed1-x54a.google.com [IPv6:2a00:1450:4864:20::54a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 5071BC0613ED for ; Mon, 18 Jan 2021 08:01:56 -0800 (PST) Received: by mail-ed1-x54a.google.com with SMTP id a9so8085976edy.8 for ; Mon, 18 Jan 2021 08:01:56 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=sender:date:in-reply-to:message-id:mime-version:references:subject :from:to:cc; bh=TqkGDF1ta5PCdnxEEvsF8Ma1Lt/vVVNhRWpTG6LTrD8=; b=skeG0dILnijwcANaFRzfFG8rns/gfweOPnEBdnioVj37CH0jabLoyCs8pkSk9UokwC Cq+ktrPAYJ9ABubh9LzgMr/5AZdBTGTaR1Ph8E6xbry2rqtZdl0jYnCPoEBEI6jwtW77 DqNVltbUjUHsljLeFb1o7erBKBnYqAARQfPyQK2cXwmmJEg0W23x9HfmxDYW/QJnDuX6 fX3FpqMOKfNLQnV9RcX9JqGCfVayXjjyawj6DAn4Sfn/E9DB7/ZFpfcVATHAncOxE8C2 gjWmeOyp1sSGA41DwWg4HU10TqQinbYXP5hCupAr6THMXjp7knQlllZVpz7rGh2/6x1H rIhg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=TqkGDF1ta5PCdnxEEvsF8Ma1Lt/vVVNhRWpTG6LTrD8=; b=RMidPznPuu2TWsKqVVocxUQuZ5jj49T3rI/LcYTGcJYg+CS2ond834dtBRl0x4ff38 lgQZgQFTiRJ2bAdZzlMJDY6iJDfTVUlsSaNtUVV/CQzrRlgzmvWWvBXZV7TvxaQgtsUg vUYsvSDGhiZTlohDfqXuKZcXyqrs2RGwIZH4+T8jyLf38AFQY4RyAHfO00MCeuMmJLNf exUVGjIMa3WZfMV5qtij/XtfbMvkG/f6ua3k4swGE2RQBE9blt/tH2uO/jM8sBrGtjur f2/TNdmVlha5HD5Y3FLxwc4JOUoKjTszAxi09BHu/r40R32u/HQXLN711/VF71YYriBh P41w== X-Gm-Message-State: AOAM531rqCXatVMedubhnX8K1pUEYI9eP2VUTDrEzjP7Qt1MyTuWylt9 W8tatLYVnVs8Ve4xyFD40/tXJ4RqgiQJHQ== X-Google-Smtp-Source: ABdhPJyUWrBT4UlLd93wmvwwr+Ba6wo0Z3mXx1DRRmGWRLYjv9cnrAdfGCj0xvRwKN6BhYXAA17iu5VlIxUdWA== Sender: "gprocida via sendgmr" X-Received: from tef.lon.corp.google.com ([2a00:79e0:d:110:a6ae:11ff:fe11:4f04]) (user=gprocida job=sendgmr) by 2002:a05:6402:158:: with SMTP id s24mr119650edu.19.1610985714831; Mon, 18 Jan 2021 08:01:54 -0800 (PST) Date: Mon, 18 Jan 2021 16:01:39 +0000 In-Reply-To: <20210118160139.1971039-1-gprocida@google.com> Message-Id: <20210118160139.1971039-4-gprocida@google.com> Mime-Version: 1.0 References: <20210118160139.1971039-1-gprocida@google.com> X-Mailer: git-send-email 2.30.0.284.gd98b1dd5eaa7-goog Subject: [PATCH 3/3] btf_encoder: Set .BTF section alignment to 16 From: Giuliano Procida To: dwarves@vger.kernel.org Cc: kernel-team@android.com, maennich@google.com, ast@kernel.org, andrii@kernel.org, bpf@vger.kernel.org, kernel-team@fb.com, Giuliano Procida Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org This is to avoid misaligned access when memory-mapping ELF sections. Signed-off-by: Giuliano Procida --- libbtf.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/libbtf.c b/libbtf.c index 7552d8e..2f12d53 100644 --- a/libbtf.c +++ b/libbtf.c @@ -797,6 +797,14 @@ static int btf_elf__write(const char *filename, struct btf *btf) goto unlink; } + snprintf(cmd, sizeof(cmd), "%s --set-section-alignment .BTF=16 %s", + llvm_objcopy, filename); + if (system(cmd)) { + /* non-fatal, this is a nice-to-have and it's only supported from LLVM 10 */ + fprintf(stderr, "%s: warning: failed to align .BTF section in '%s': %d!\n", + __func__, filename, errno); + } + err = 0; unlink: unlink(tmp_fn);