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=-15.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 A2C81C433DB for ; Mon, 15 Mar 2021 09:25:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6D00164E21 for ; Mon, 15 Mar 2021 09:25:22 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229524AbhCOJYv (ORCPT ); Mon, 15 Mar 2021 05:24:51 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41718 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229614AbhCOJYW (ORCPT ); Mon, 15 Mar 2021 05:24:22 -0400 Received: from mail-ej1-x62b.google.com (mail-ej1-x62b.google.com [IPv6:2a00:1450:4864:20::62b]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A9FA2C06175F for ; Mon, 15 Mar 2021 02:24:21 -0700 (PDT) Received: by mail-ej1-x62b.google.com with SMTP id ci14so64770778ejc.7 for ; Mon, 15 Mar 2021 02:24:21 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=isovalent-com.20150623.gappssmtp.com; s=20150623; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=UDrvpL3Clc7HH5Rd2kY9nbHs/9D7B75ztyk400CQFNU=; b=t+t6m1MVq0U2ew9743tWpLI1BSdUDJNGfntFQrczl6hBy4Mwdv6esYa+N377FUHmOj DDxgA/whe2RjlDHYyN/TuuIObrZNoR9MeTWMhdcgmXvLnQvXsMXxEID09v9/aNGjeU5e W79ZoFKJtKCN30F4LSmUCIr0f/eWQIBG51Bw53ViuD678X4qbBxS+/KokqodgBiKSslr vBk4BUxMOIDom8P/1QY5yqP1LLoeOSb5hla1ntWHANEEFJ2bToVcFCTxCFN8BpIXvvNR W7u8Ogd9+iPk5jqn4omAtypPlzipscecGANAbOGpFsFt4gH+MSXxmrlC2v9CbaMTjY80 vj/A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=UDrvpL3Clc7HH5Rd2kY9nbHs/9D7B75ztyk400CQFNU=; b=S9QEXtnqn20YdQk8L8ZWMPFwwnxNUjZJY0iGOsbpEexibMR9yRImvMziQNLM2Ii+oZ laaviXpVx1+n6NY+kNSnApMst1zSCp73SiKET7gaxZ2B8jwg1bT6EiIl68vqGeucunDO FK68Dg3vAakV2Hezkv8V9MPzNos/p/Ym4NE/qF+v177+U7YD0VNLZrJbAW7JVhbr4zvU pC06L0vP8mGtl58OLay9jDvf+FosEj2bcz2JyI+TyzMzMOw1tpetk2LrnTw248ecS0iu 5wi+I0vILxwM/jBPJK5Z95rmnoq03cZ2RKIp6ab4o/rVz7i4B5jkdVFeT19bBXwLrlaj gd+Q== X-Gm-Message-State: AOAM530f4n5/wrZhBoM3l/ZwOVL7XdS/iD1s6njewjaeGOdQgY+O6qlk U2KGZXjzP5SnWUM3x0Xovc9qWQ== X-Google-Smtp-Source: ABdhPJx/6Q0IBjRNygpcd54E5muTxxpkMWkch05Ktvl/mCb29O8q4VJ+3Xn+29RXsTNKskXgE9NJmQ== X-Received: by 2002:a17:906:d9d1:: with SMTP id qk17mr22283463ejb.52.1615800260406; Mon, 15 Mar 2021 02:24:20 -0700 (PDT) Received: from [192.168.1.8] ([194.35.119.239]) by smtp.gmail.com with ESMTPSA id mc2sm6754929ejb.115.2021.03.15.02.24.19 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 15 Mar 2021 02:24:19 -0700 (PDT) Subject: Re: [PATCH v2 bpf-next 08/11] bpftool: add `gen object` command to perform BPF static linking To: Andrii Nakryiko , bpf@vger.kernel.org, netdev@vger.kernel.org, ast@fb.com, daniel@iogearbox.net Cc: kernel-team@fb.com References: <20210313193537.1548766-1-andrii@kernel.org> <20210313193537.1548766-9-andrii@kernel.org> From: Quentin Monnet Message-ID: Date: Mon, 15 Mar 2021 09:24:19 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.8.1 MIME-Version: 1.0 In-Reply-To: <20210313193537.1548766-9-andrii@kernel.org> Content-Type: text/plain; charset=utf-8 Content-Language: en-GB Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org 2021-03-13 11:35 UTC-0800 ~ Andrii Nakryiko > Add `bpftool gen object ...` command to statically > link multiple BPF ELF object files into a single output BPF ELF object file. > > Similarly to existing '*.o' convention, bpftool is establishing a '*.bpfo' > convention for statically-linked BPF object files. Both .o and .bpfo suffixes > will be stripped out during BPF skeleton generation to infer BPF object name. > > This patch also updates bash completions and man page. Man page gets a short > section on `gen object` command, but also updates the skeleton example to show > off workflow for BPF application with two .bpf.c files, compiled individually > with Clang, then resulting object files are linked together with `gen object`, > and then final object file is used to generate usable BPF skeleton. This > should help new users understand realistic workflow w.r.t. compiling > mutli-file BPF application. > > Signed-off-by: Andrii Nakryiko > --- > .../bpf/bpftool/Documentation/bpftool-gen.rst | 65 +++++++++++++++---- > tools/bpf/bpftool/bash-completion/bpftool | 2 +- > tools/bpf/bpftool/gen.c | 49 +++++++++++++- > 3 files changed, 99 insertions(+), 17 deletions(-) > > diff --git a/tools/bpf/bpftool/Documentation/bpftool-gen.rst b/tools/bpf/bpftool/Documentation/bpftool-gen.rst > index 84cf0639696f..4cdce187c393 100644 > --- a/tools/bpf/bpftool/Documentation/bpftool-gen.rst > +++ b/tools/bpf/bpftool/Documentation/bpftool-gen.rst > @@ -14,16 +14,37 @@ SYNOPSIS > > *OPTIONS* := { { **-j** | **--json** } [{ **-p** | **--pretty** }] } > > - *COMMAND* := { **skeleton** | **help** } > + *COMMAND* := { **object** | **skeleton** | **help** } > > GEN COMMANDS > ============= > > +| **bpftool** **gen object** *OUTPUT_FILE* *INPUT_FILE* [*INPUT_FILE*...] > | **bpftool** **gen skeleton** *FILE* > | **bpftool** **gen help** > > DESCRIPTION > =========== > + **bpftool gen object** *OUTPUT_FILE* *INPUT_FILE* [*INPUT_FILE*...] > + Statically link (combine) together one or more *INPUT_FILE*'s > + into a single resulting *OUTPUT_FILE*. All the files involed Typo: "involed" > + are BPF ELF object files. > + > + The rules of BPF static linking are mostly the same as for > + user-space object files, but in addition to combining data > + and instruction sections, .BTF and .BTF.ext (if present in > + any of the input files) data are combined together. .BTF > + data is deduplicated, so all the common types across > + *INPUT_FILE*'s will only be represented once in the resulting > + BTF information. > + > + BPF static linking allows to partition BPF source code into > + individually compiled files that are then linked into > + a single resulting BPF object file, which can be used to > + generated BPF skeleton (with **gen skeleton** command) or > + passed directly into **libbpf** (using **bpf_object__open()** > + family of APIs). > + > **bpftool gen skeleton** *FILE* > Generate BPF skeleton C header file for a given *FILE*. > > diff --git a/tools/bpf/bpftool/bash-completion/bpftool b/tools/bpf/bpftool/bash-completion/bpftool > index fdffbc64c65c..7ca23c58f2c0 100644 > --- a/tools/bpf/bpftool/bash-completion/bpftool > +++ b/tools/bpf/bpftool/bash-completion/bpftool > @@ -981,7 +981,7 @@ _bpftool() > ;; > gen) > case $command in > - skeleton) > + object|skeleton) > _filedir > ;; > *) Suggesting the "object" keyword for completing "bpftool gen [tab]" is missing. It is just a few lines below: ------ diff --git a/tools/bpf/bpftool/bash-completion/bpftool b/tools/bpf/bpftool/bash-completion/bpftool index fdffbc64c65c..223438e86932 100644 --- a/tools/bpf/bpftool/bash-completion/bpftool +++ b/tools/bpf/bpftool/bash-completion/bpftool @@ -981,12 +981,12 @@ _bpftool() ;; gen) case $command in - skeleton) + object|skeleton) _filedir ;; *) [[ $prev == $object ]] && \ - COMPREPLY=( $( compgen -W 'skeleton help' -- "$cur" ) ) + COMPREPLY=( $( compgen -W 'object skeleton help' -- "$cur" ) ) ;; esac ;; ------ Looks good otherwise. Thanks for the documentation, it's great to have the example in the man page. Pending the two nits above are fixed: Reviewed-by: Quentin Monnet Quentin