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=-15.4 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,URIBL_BLOCKED, 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 DDDB2C4338F for ; Fri, 30 Jul 2021 21:48:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BC3E260560 for ; Fri, 30 Jul 2021 21:48:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231939AbhG3Vsq (ORCPT ); Fri, 30 Jul 2021 17:48:46 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40234 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232140AbhG3Vs2 (ORCPT ); Fri, 30 Jul 2021 17:48:28 -0400 Received: from mail-wm1-x331.google.com (mail-wm1-x331.google.com [IPv6:2a00:1450:4864:20::331]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 74AE4C061765 for ; Fri, 30 Jul 2021 14:48:20 -0700 (PDT) Received: by mail-wm1-x331.google.com with SMTP id o7-20020a05600c5107b0290257f956e02dso3614352wms.1 for ; Fri, 30 Jul 2021 14:48:20 -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=6YN1J9vmLUXCKWdwBvhu6EMYabwP3L6uMfluwtn0R3A=; b=c3mmn9++MAOPBsxBE4zfM9z3wJVdVzoag+AB1FYJ3QLZEZc2RWZVkgFbokBEe0sVWj yivSGt3NX4cmPokSjEkqAJYd3iOnN36L3hsg7ka9EKFzoMqlAlM9Pz+8FWb8hpEpJmQA j3j3ofsurRtgETgpa89z8dbuLbHJ7TixqHy6OvNp0SbANRgRVVrO6wriBPfr04nb9LK2 qGoOCEizKukGqX6Jr02Ypya8RNjjrKiwKUKQRzqJuWgAIhF9lTBbsDuOwTxxd5woG9zw pvHQl8UqZ/+eAXpH8x2Fq5rm/D8BGRBduunhGcZptoduWOqhbrGpqMLecPQxiPP90p1S YReQ== 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=6YN1J9vmLUXCKWdwBvhu6EMYabwP3L6uMfluwtn0R3A=; b=Sooz4Ba7oITVWPLmN5k6oGy6M9FIkD/UE7fGJeLp23vR9J1bF/nafKwdn3ksFRy1Ao 7W7wz2EPOZQZDbWkK22dO0VC0cNojED2IQRq8dCVQK79uWzJSQ5VM1XJn45T8e1oiPTT DKPlJwS4O+3BiJHbp4uPyJ07YSlGj70uF6vCp5Kfc7dN1yulOFQ1UT02fxPGXKpiyJg3 atxAFvyzSjv1b/nXs/egpMmG0xvjAT6fz5cVK7IMQkCLO2aWYrTP0YrL4QRzFmTOk3ot tSi+ZXpbQgd4mqhbOdmvfkQvj1CWh0zlFu/AyprzSiwvnlqKHUTJ0tgcuvsS5F1qFxI7 67IQ== X-Gm-Message-State: AOAM532hcWz9YWKCUVVOtgMUjlH5g4XaQ9Fs6/4RyBOcfFVfpbVFdPpW DG0NMzpoZrB1Y0/BcYfwR6McZILlwIPuTRjh X-Google-Smtp-Source: ABdhPJwhpXwCZmWPCzIsEX0advg+wYnkEjnxSySmGcoqiAXT/eUhd4oS6Nmj+awvShpOH4qbKxE05w== X-Received: by 2002:a05:600c:4fd6:: with SMTP id o22mr307741wmq.45.1627681698708; Fri, 30 Jul 2021 14:48:18 -0700 (PDT) Received: from [192.168.1.8] ([149.86.68.125]) by smtp.gmail.com with ESMTPSA id i7sm3113516wre.64.2021.07.30.14.48.17 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 30 Jul 2021 14:48:18 -0700 (PDT) Subject: Re: [PATCH bpf-next 6/7] tools: bpftool: document and add bash completion for -L, -B options To: Andrii Nakryiko Cc: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Networking , bpf References: <20210729162932.30365-1-quentin@isovalent.com> <20210729162932.30365-7-quentin@isovalent.com> From: Quentin Monnet Message-ID: <4ad2073f-d528-788e-3222-85cd2c0fe5f9@isovalent.com> Date: Fri, 30 Jul 2021 22:48:16 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.12.0 MIME-Version: 1.0 In-Reply-To: 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 2021-07-30 11:59 UTC-0700 ~ Andrii Nakryiko > On Thu, Jul 29, 2021 at 9:29 AM Quentin Monnet wrote: >> >> The -L|--use-loader option for using loader programs when loading, or >> when generating a skeleton, did not have any documentation or bash >> completion. Same thing goes for -B|--base-btf, used to pass a path to a >> base BTF object for split BTF such as BTF for kernel modules. >> >> This patch documents and adds bash completion for those options. >> >> Fixes: 75fa1777694c ("tools/bpftool: Add bpftool support for split BTF") >> Fixes: d510296d331a ("bpftool: Use syscall/loader program in "prog load" and "gen skeleton" command.") >> Signed-off-by: Quentin Monnet >> --- >> Note: The second example with base BTF in the BTF man page assumes that >> dumping split BTF when objects are passed by id is supported. Support is >> currently pending review in another PR. >> --- > > Not anymore :) > > [...] > >> @@ -73,6 +74,20 @@ OPTIONS >> ======= >> .. include:: common_options.rst >> >> + -B, --base-btf *FILE* >> + Pass a base BTF object. Base BTF objects are typically used >> + with BTF objects for kernel modules. To avoid duplicating >> + all kernel symbols required by modules, BTF objects for >> + modules are "split", they are built incrementally on top of >> + the kernel (vmlinux) BTF object. So the base BTF reference >> + should usually point to the kernel BTF. >> + >> + When the main BTF object to process (for example, the >> + module BTF to dump) is passed as a *FILE*, bpftool attempts >> + to autodetect the path for the base object, and passing >> + this option is optional. When the main BTF object is passed >> + through other handles, this option becomes necessary. >> + >> EXAMPLES >> ======== >> **# bpftool btf dump id 1226** >> @@ -217,3 +232,34 @@ All the standard ways to specify map or program are supported: >> **# bpftool btf dump prog tag b88e0a09b1d9759d** >> >> **# bpftool btf dump prog pinned /sys/fs/bpf/prog_name** >> + >> +| >> +| **# bpftool btf dump file /sys/kernel/btf/i2c_smbus** >> +| (or) >> +| **# I2C_SMBUS_ID=$(bpftool btf show -p | jq '.[] | select(.name=="i2c_smbus").id')** >> +| **# bpftool btf dump id ${I2C_SMBUS_ID} -B /sys/kernel/btf/vmlinux** >> + >> +:: >> + >> + [104848] STRUCT 'i2c_smbus_alert' size=40 vlen=2 >> + 'alert' type_id=393 bits_offset=0 >> + 'ara' type_id=56050 bits_offset=256 >> + [104849] STRUCT 'alert_data' size=12 vlen=3 >> + 'addr' type_id=16 bits_offset=0 >> + 'type' type_id=56053 bits_offset=32 >> + 'data' type_id=7 bits_offset=64 >> + [104850] PTR '(anon)' type_id=104848 >> + [104851] PTR '(anon)' type_id=104849 >> + [104852] FUNC 'i2c_register_spd' type_id=84745 linkage=static >> + [104853] FUNC 'smbalert_driver_init' type_id=1213 linkage=static >> + [104854] FUNC_PROTO '(anon)' ret_type_id=18 vlen=1 >> + 'ara' type_id=56050 >> + [104855] FUNC 'i2c_handle_smbus_alert' type_id=104854 linkage=static >> + [104856] FUNC 'smbalert_remove' type_id=104854 linkage=static >> + [104857] FUNC_PROTO '(anon)' ret_type_id=18 vlen=2 >> + 'ara' type_id=56050 >> + 'id' type_id=56056 >> + [104858] FUNC 'smbalert_probe' type_id=104857 linkage=static >> + [104859] FUNC 'smbalert_work' type_id=9695 linkage=static >> + [104860] FUNC 'smbus_alert' type_id=71367 linkage=static >> + [104861] FUNC 'smbus_do_alert' type_id=84827 linkage=static > > This reminded be that it would be awesome to support "format c" > use-case for dumping split BTF in a more sane way. I.e., instead of > dumping all types from base and split BTF, only dump necessary (used) > forward declarations from base BTF, and then full C dump of only new > types from the split (module) BTF. This will become more important as > people will start using module BTF more. It's an interesting add-on to > libbpf's btf_dumper functionality. Not sure how hard that would be, > but I'd imagine it shouldn't require much changes. > > Just in case anyone wanted to challenge themselves with some more > algorithmic patch for libbpf (*wink wink*)... If you're addressing this to me, I'm not particularly looking for such challenge at the moment :). In fact I already noted a few things that I would like to fix or improve for bpftool, I will append this one to the list. I should maybe start thinking of a tracker of some sort to list and share this.