From mboxrd@z Thu Jan 1 00:00:00 1970 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=-19.2 required=3.0 tests=DKIMWL_WL_MED,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FSL_HELO_FAKE,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,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 EDB75C3F2CE for ; Tue, 17 Mar 2020 01:17:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C594B206C0 for ; Tue, 17 Mar 2020 01:17:00 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=google.com header.i=@google.com header.b="qF4LpAOH" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1733017AbgCQBRA (ORCPT ); Mon, 16 Mar 2020 21:17:00 -0400 Received: from mail-pj1-f68.google.com ([209.85.216.68]:50288 "EHLO mail-pj1-f68.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1733101AbgCQBQ7 (ORCPT ); Mon, 16 Mar 2020 21:16:59 -0400 Received: by mail-pj1-f68.google.com with SMTP id v13so46354pjb.0 for ; Mon, 16 Mar 2020 18:16:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:from:to:cc:subject:message-id:mime-version:content-disposition; bh=I6cJtFY7hJqIXMiYqUICiIaIcWOpJ+YQ+ECPyBPa2wE=; b=qF4LpAOHQN7tV5w1vxq0S6m4vFWtxrINpF1GqnoNLygPAR+w6fIrvbgNnBFcPZxlyG qzODdDvvh/EqJBsBWiIFnWigbF+0Kfmd4Rlil/RH6jhIwVW4mDYshdORPpyPyeklv8rO H6WlJIdGolzKm3hBLHyacFemnw5WguCfjctt2WppCDAUtbzz5bVlO8IVBmbiI9TdwKcc AQ5CnT7KQieTFkO6xCfBMfXrYmhk40DcNLKLcLgY61IZKThWuEz/EMfsEQSrxzWu/fAC VzWb6wREEYvUbN4xaPuzseMYJmWAuJffWqc6s11kmdT5WCQMZsdcJIfbUrxx6PtUqT2c iopA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:from:to:cc:subject:message-id:mime-version :content-disposition; bh=I6cJtFY7hJqIXMiYqUICiIaIcWOpJ+YQ+ECPyBPa2wE=; b=OsrGU/iLo63yoJz1/zcdlkpW8DLGYUJUY64PwH0L45d3o3hm5LskUqNJ9NIpU2keqV vx3CPaBAep4JT/Q4xlNz++esCp6Z3EE64BOUJNCb61zA6VUdms5tXfVY71NZuBsOiVgG 57aj5xP6oasNs2d7m6aN2GKwn6f695s8K6VmpcDV6AHDbtohhqNIJU9kMfZ0lbPpMekJ 33UX2aZ0linh3M8Jxg9tSwEyGKFI47fTIt+vN6LopSJt9zrpZf/PT5+bHg/GDQfvyXKa k/qTN3PXA0rrTxTc8oEjvx1j2q+41h8jL6A8VZoHxa//D/4GS6ps2zZDn4fNUAK4Ew4v wOZQ== X-Gm-Message-State: ANhLgQ1/glVtWD83sARSY2y40LaUsd4sc4zie7P1Sr1rrPmYJQN0xdfa ujXQc6L/q3+G4x3z+rpCJhmw0tGetCLogO+/ X-Google-Smtp-Source: ADFU+vvGv1cNBCN2udI5vdsCW+KdUNx4wY5wxFh3hPWrzoY2njnyN91VG8NxGe2uapQjnmBkNz0YCg== X-Received: by 2002:a17:902:7441:: with SMTP id e1mr1829956plt.291.1584407817721; Mon, 16 Mar 2020 18:16:57 -0700 (PDT) Received: from google.com ([2620:15c:2ce:0:9efe:9f1:9267:2b27]) by smtp.gmail.com with ESMTPSA id c11sm1027287pfc.216.2020.03.16.18.16.56 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 16 Mar 2020 18:16:56 -0700 (PDT) Date: Mon, 16 Mar 2020 18:16:54 -0700 From: Fangrui Song To: bpf@vger.kernel.org, netdev@vger.kernel.org Cc: daniel@iogearbox.net, Nick Desaulniers , Nathan Chancellor , clang-built-linux@googlegroups.com, Stanislav Fomichev , davem@davemloft.net, ast@kernel.org Subject: [PATCH bpf] bpf: Support llvm-objcopy and llvm-objdump for vmlinux BTF Message-ID: <20200317011654.zkx5r7so53skowlc@google.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Simplify gen_btf logic to make it work with llvm-objcopy and llvm-objdump. We just need to retain one section .BTF. To do so, we can use a simple objcopy --only-section=.BTF instead of jumping all the hoops via an architecture-less binary file. We use a dd comment to change the e_type field in the ELF header from ET_EXEC to ET_REL so that .btf.vmlinux.bin.o will be accepted by lld. Fixes: df786c9b9476 ("bpf: Force .BTF section start to zero when dumping from vmlinux") Cc: Stanislav Fomichev Cc: Nick Desaulniers Tested-by: Nick Desaulniers Reported-by: Nathan Chancellor Link: https://github.com/ClangBuiltLinux/linux/issues/871 Signed-off-by: Fangrui Song --- scripts/link-vmlinux.sh | 13 ++----------- 1 file changed, 2 insertions(+), 11 deletions(-) diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh index dd484e92752e..84be8d7c361d 100755 --- a/scripts/link-vmlinux.sh +++ b/scripts/link-vmlinux.sh @@ -120,18 +120,9 @@ gen_btf() info "BTF" ${2} vmlinux_link ${1} - LLVM_OBJCOPY=${OBJCOPY} ${PAHOLE} -J ${1} - # dump .BTF section into raw binary file to link with final vmlinux - bin_arch=$(LANG=C ${OBJDUMP} -f ${1} | grep architecture | \ - cut -d, -f1 | cut -d' ' -f2) - bin_format=$(LANG=C ${OBJDUMP} -f ${1} | grep 'file format' | \ - awk '{print $4}') - ${OBJCOPY} --change-section-address .BTF=0 \ - --set-section-flags .BTF=alloc -O binary \ - --only-section=.BTF ${1} .btf.vmlinux.bin - ${OBJCOPY} -I binary -O ${bin_format} -B ${bin_arch} \ - --rename-section .data=.BTF .btf.vmlinux.bin ${2} + # Extract .BTF section, change e_type to ET_REL, to link with final vmlinux + ${OBJCOPY} --only-section=.BTF ${1} ${2} && printf '\1' | dd of=${2} conv=notrunc bs=1 seek=16 } # Create ${2} .o file with all symbols from the ${1} object file -- 2.25.1.481.gfbce0eb801-goog