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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id B9037C6FA82 for ; Mon, 12 Sep 2022 15:38:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229969AbiILPiJ (ORCPT ); Mon, 12 Sep 2022 11:38:09 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:36864 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230335AbiILPiF (ORCPT ); Mon, 12 Sep 2022 11:38:05 -0400 Received: from out30-43.freemail.mail.aliyun.com (out30-43.freemail.mail.aliyun.com [115.124.30.43]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 61F7325595; Mon, 12 Sep 2022 08:38:03 -0700 (PDT) X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R251e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=ay29a033018045192;MF=chentao.kernel@linux.alibaba.com;NM=1;PH=DS;RN=12;SR=0;TI=SMTPD_---0VPXqnu2_1662997076; Received: from 30.15.230.77(mailfrom:chentao.kernel@linux.alibaba.com fp:SMTPD_---0VPXqnu2_1662997076) by smtp.aliyun-inc.com; Mon, 12 Sep 2022 23:37:57 +0800 Message-ID: Date: Mon, 12 Sep 2022 23:37:56 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:91.0) Gecko/20100101 Thunderbird/91.13.0 Subject: Re: [PATCH] libbpf: Support raw btf placed in the default path To: Andrii Nakryiko Cc: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , netdev@vger.kernel.org, bpf@vger.kernel.org, linux-kernel@vger.kernel.org References: <1661349907-57222-1-git-send-email-chentao.kernel@linux.alibaba.com> From: Tao Chen In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 在 2022/9/10 上午3:00, Andrii Nakryiko 写道: > On Sun, Aug 28, 2022 at 10:36 PM Tao Chen > wrote: >> >> Hi Nakryiko, thank you for your reply. Yes, i happed to put the raw >> BTF made by myself in /boot on kernel4.19, unluckly it reported error. >> So is it possible to allow the raw BTF in /boot directly, athough we >> can set the specified btf location again to solve the problem with the >> bpf_object_open_opts interface. >> >> As you say, maybe we can remove the locations[i].raw_btf check, just >> use the btf__parse, It looks more concise. > > Please don't top post, reply inline (that's kernel mail lists rules). > > But yes, I think we can just use btf__parse and let libbpf figure out. > Please send a patch. > Thank you, i will send the patch in v2. >> >> 在 2022/8/26 上午4:26, Andrii Nakryiko 写道: >> >> On Wed, Aug 24, 2022 at 7:05 AM chentao.ct >> wrote: >> >> Now only elf btf can be placed in the default path, raw btf should >> also can be there. >> >> It's not clear what you are trying to achieve. Do you want libbpf to >> attempt to load /boot/vmlinux-%1$s as raw BTF as well (so you can sort >> of sneak in pregenerated BTF), or what exactly? >> btf__load_vmlinux_btf() code already supports loading raw BTF, it just >> needs to be explicitly specified in locations table. >> >> So with your change locations[i].raw_btf check doesn't make sense and >> we need to clean this up. >> >> But first, let's discuss the use case, instead of your specific solution. >> >> >> Signed-off-by: chentao.ct >> --- >> tools/lib/bpf/btf.c | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c >> index bb1e06e..b22b5b3 100644 >> --- a/tools/lib/bpf/btf.c >> +++ b/tools/lib/bpf/btf.c >> @@ -4661,7 +4661,7 @@ struct btf *btf__load_vmlinux_btf(void) >> } locations[] = { >> /* try canonical vmlinux BTF through sysfs first */ >> { "/sys/kernel/btf/vmlinux", true /* raw BTF */ }, >> - /* fall back to trying to find vmlinux ELF on disk otherwise */ >> + /* fall back to trying to find vmlinux RAW/ELF on disk otherwise */ >> { "/boot/vmlinux-%1$s" }, >> { "/lib/modules/%1$s/vmlinux-%1$s" }, >> { "/lib/modules/%1$s/build/vmlinux" }, >> @@ -4686,7 +4686,7 @@ struct btf *btf__load_vmlinux_btf(void) >> if (locations[i].raw_btf) >> btf = btf__parse_raw(path); >> else >> - btf = btf__parse_elf(path, NULL); >> + btf = btf__parse(path, NULL); >> err = libbpf_get_error(btf); >> pr_debug("loading kernel BTF '%s': %d\n", path, err); >> if (err) >> -- >> 2.2.1 >>