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=-9.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 4EF5BC43461 for ; Thu, 17 Sep 2020 09:54:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E9B6920838 for ; Thu, 17 Sep 2020 09:54:35 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="IknfHHJn" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726520AbgIQJyc (ORCPT ); Thu, 17 Sep 2020 05:54:32 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:49238 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726318AbgIQJy1 (ORCPT ); Thu, 17 Sep 2020 05:54:27 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1600336464; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=PfgTD4QYp7HdelC/Cdt/0p7DJlm562Qxcolq6GnkE9E=; b=IknfHHJniumpYiT/JzVvMXvYOFDSXryZZecG2Z2KWKUV763Y0AD9V40w3siaMVf8XaD/vP s7MdOUdIjiAo4CxW9HglXwWbrUnz7t23Y4c64TF0/QcAL3CxmKM8pZBCU0u4iWBmHcFK56 3KS/ggwqJMcYHLI5v4pFbfDP/X/WiZw= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-353-vgJu2ttfNdah2wYv3YNUsQ-1; Thu, 17 Sep 2020 05:54:20 -0400 X-MC-Unique: vgJu2ttfNdah2wYv3YNUsQ-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id BDA5681F03B; Thu, 17 Sep 2020 09:54:18 +0000 (UTC) Received: from krava (ovpn-114-176.ams2.redhat.com [10.36.114.176]) by smtp.corp.redhat.com (Postfix) with SMTP id 273927BE44; Thu, 17 Sep 2020 09:54:16 +0000 (UTC) Date: Thu, 17 Sep 2020 11:54:15 +0200 From: Jiri Olsa To: Seth Forshee Cc: Jiri Olsa , Alexei Starovoitov , Daniel Borkmann , netdev@vger.kernel.org, bpf@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: resolve_btfids breaks kernel cross-compilation Message-ID: <20200917095415.GG2411168@krava> References: <20200916194733.GA4820@ubuntu-x1> <20200917080452.GB2411168@krava> <20200917083809.GE2411168@krava> <20200917091406.GF2411168@krava> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200917091406.GF2411168@krava> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Thu, Sep 17, 2020 at 11:14:08AM +0200, Jiri Olsa wrote: > On Thu, Sep 17, 2020 at 10:38:12AM +0200, Jiri Olsa wrote: > > On Thu, Sep 17, 2020 at 10:04:55AM +0200, Jiri Olsa wrote: > > > On Wed, Sep 16, 2020 at 02:47:33PM -0500, Seth Forshee wrote: > > > > The requirement to build resolve_btfids whenever CONFIG_DEBUG_INFO_BTF > > > > is enabled breaks some cross builds. For example, when building a 64-bit > > > > powerpc kernel on amd64 I get: > > > > > > > > Auto-detecting system features: > > > > ... libelf: [ [32mon[m ] > > > > ... zlib: [ [32mon[m ] > > > > ... bpf: [ [31mOFF[m ] > > > > > > > > BPF API too old > > > > make[6]: *** [Makefile:295: bpfdep] Error 1 > > > > > > > > The contents of tools/bpf/resolve_btfids/feature/test-bpf.make.output: > > > > > > > > In file included from /home/sforshee/src/u-k/unstable/tools/arch/powerpc/include/uapi/asm/bitsperlong.h:11, > > > > from /usr/include/asm-generic/int-ll64.h:12, > > > > from /usr/include/asm-generic/types.h:7, > > > > from /usr/include/x86_64-linux-gnu/asm/types.h:1, > > > > from /home/sforshee/src/u-k/unstable/tools/include/linux/types.h:10, > > > > from /home/sforshee/src/u-k/unstable/tools/include/uapi/linux/bpf.h:11, > > > > from test-bpf.c:3: > > > > /home/sforshee/src/u-k/unstable/tools/include/asm-generic/bitsperlong.h:14:2: error: #error Inconsistent word size. Check asm/bitsperlong.h > > > > 14 | #error Inconsistent word size. Check asm/bitsperlong.h > > > > | ^~~~~ > > > > > > > > This is because tools/arch/powerpc/include/uapi/asm/bitsperlong.h sets > > > > __BITS_PER_LONG based on the predefinied compiler macro __powerpc64__, > > > > which is not defined by the host compiler. What can we do to get cross > > > > builds working again? > > > > > > could you please share the command line and setup? > > > > I just reproduced.. checking on fix > > I still need to check on few things, but patch below should help > > we might have a problem for cross builds with different endianity > than the host because libbpf does not support reading BTF data > with different endianity, and we get: > > BTFIDS vmlinux > libbpf: non-native ELF endianness is not supported > > jirka > > > --- > diff --git a/tools/bpf/resolve_btfids/Makefile b/tools/bpf/resolve_btfids/Makefile > index a88cd4426398..d3c818b8d8d3 100644 > --- a/tools/bpf/resolve_btfids/Makefile > +++ b/tools/bpf/resolve_btfids/Makefile > @@ -1,5 +1,6 @@ > # SPDX-License-Identifier: GPL-2.0-only > include ../../scripts/Makefile.include > +include ../../scripts/Makefile.arch > > ifeq ($(srctree),) > srctree := $(patsubst %/,%,$(dir $(CURDIR))) > @@ -29,6 +30,7 @@ endif > AR = $(HOSTAR) > CC = $(HOSTCC) > LD = $(HOSTLD) > +ARCH = $(HOSTARCH) > > OUTPUT ?= $(srctree)/tools/bpf/resolve_btfids/ > and I realized we can have CONFIG_DEBUG_INFO_BTF without CONFIG_BPF, so we need also fix below for such cases jirka --- diff --git a/scripts/link-vmlinux.sh b/scripts/link-vmlinux.sh index e6e2d9e5ff48..8a990933a690 100755 --- a/scripts/link-vmlinux.sh +++ b/scripts/link-vmlinux.sh @@ -343,7 +343,10 @@ vmlinux_link vmlinux "${kallsymso}" ${btf_vmlinux_bin_o} # fill in BTF IDs if [ -n "${CONFIG_DEBUG_INFO_BTF}" ]; then info BTFIDS vmlinux -${RESOLVE_BTFIDS} vmlinux +if [ -z "${CONFIG_BPF}" ]; then + no_fail=--no-fail +fi +${RESOLVE_BTFIDS} $no_fail vmlinux fi if [ -n "${CONFIG_BUILDTIME_TABLE_SORT}" ]; then