From patchwork Mon Feb 22 21:49:10 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ilya Leoshkevich X-Patchwork-Id: 12099557 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=-16.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 3AE52C433DB for ; Mon, 22 Feb 2021 21:50:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0343864DFD for ; Mon, 22 Feb 2021 21:50:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231664AbhBVVuu (ORCPT ); Mon, 22 Feb 2021 16:50:50 -0500 Received: from mx0b-001b2d01.pphosted.com ([148.163.158.5]:42914 "EHLO mx0a-001b2d01.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S231638AbhBVVum (ORCPT ); Mon, 22 Feb 2021 16:50:42 -0500 Received: from pps.filterd (m0098420.ppops.net [127.0.0.1]) by mx0b-001b2d01.pphosted.com (8.16.0.43/8.16.0.43) with SMTP id 11MLYMXw060741; Mon, 22 Feb 2021 16:49:48 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=ibm.com; h=from : to : cc : subject : date : message-id : mime-version : content-transfer-encoding; s=pp1; bh=uf/Kvz+X7vcBZK/Dc8/vlS1IwtaSQIgiJyNb3u8gv+I=; b=sNzZEzj2j8/FBlvqmm55ZDFxAkgODEcFo5R7xC/9BEzyxEUqzNGlhGXtK48U1Gl5WP9x pW//KexdubRtnFJgx4xz+AYmoScqsur1bjn6TUXQkk5Duptf5vQTvYgIwR82A6wX49qj e6JlEJWUM594qxyWRdZVgsy+Sw6ENFUodAcC1YN6YEBUpXLlFq42iI+Dmfmo9Ei7a+aQ +6l+1kiNuwWcXs4O/AfsK17HRDDvsVCKr28AqkuESg9ZQbY7Ghf1eGNTntGFlUrCAsCS F5dndSV3GxPXrMGjzBbVkmRNxFglD5AH0eRstlbBCJNDPHtdXFnFyAYjxlJnP6TPY+Ma ew== Received: from pps.reinject (localhost [127.0.0.1]) by mx0b-001b2d01.pphosted.com with ESMTP id 36vkg0360w-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 22 Feb 2021 16:49:48 -0500 Received: from m0098420.ppops.net (m0098420.ppops.net [127.0.0.1]) by pps.reinject (8.16.0.43/8.16.0.43) with SMTP id 11MLi0WM114273; Mon, 22 Feb 2021 16:49:47 -0500 Received: from ppma06ams.nl.ibm.com (66.31.33a9.ip4.static.sl-reverse.com [169.51.49.102]) by mx0b-001b2d01.pphosted.com with ESMTP id 36vkg0360c-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 22 Feb 2021 16:49:47 -0500 Received: from pps.filterd (ppma06ams.nl.ibm.com [127.0.0.1]) by ppma06ams.nl.ibm.com (8.16.0.42/8.16.0.42) with SMTP id 11MLm1Sv018397; Mon, 22 Feb 2021 21:49:45 GMT Received: from b06avi18626390.portsmouth.uk.ibm.com (b06avi18626390.portsmouth.uk.ibm.com [9.149.26.192]) by ppma06ams.nl.ibm.com with ESMTP id 36tsph21gj-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=NOT); Mon, 22 Feb 2021 21:49:45 +0000 Received: from d06av23.portsmouth.uk.ibm.com (d06av23.portsmouth.uk.ibm.com [9.149.105.59]) by b06avi18626390.portsmouth.uk.ibm.com (8.14.9/8.14.9/NCO v10.0) with ESMTP id 11MLnUOu36700602 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Mon, 22 Feb 2021 21:49:30 GMT Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id F20CCA404D; Mon, 22 Feb 2021 21:49:42 +0000 (GMT) Received: from d06av23.portsmouth.uk.ibm.com (unknown [127.0.0.1]) by IMSVA (Postfix) with ESMTP id 68F68A4040; Mon, 22 Feb 2021 21:49:42 +0000 (GMT) Received: from vm.lan (unknown [9.145.151.190]) by d06av23.portsmouth.uk.ibm.com (Postfix) with ESMTP; Mon, 22 Feb 2021 21:49:42 +0000 (GMT) From: Ilya Leoshkevich To: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Yonghong Song , Arnaldo Carvalho de Melo , John Fastabend Cc: bpf@vger.kernel.org, Heiko Carstens , Vasily Gorbik , Ilya Leoshkevich Subject: [PATCH v4 bpf-next 0/7] Add BTF_KIND_FLOAT support Date: Mon, 22 Feb 2021 22:49:10 +0100 Message-Id: <20210222214917.83629-1-iii@linux.ibm.com> X-Mailer: git-send-email 2.29.2 MIME-Version: 1.0 X-TM-AS-GCONF: 00 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.369,18.0.761 definitions=2021-02-22_07:2021-02-22,2021-02-22 signatures=0 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 adultscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 mlxlogscore=999 spamscore=0 priorityscore=1501 suspectscore=0 malwarescore=0 phishscore=0 bulkscore=0 impostorscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2102220187 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net Some BPF programs compiled on s390 fail to load, because s390 arch-specific linux headers contain float and double types. Introduce support for such types by representing them using the new BTF_KIND_FLOAT. This series deals with libbpf, bpftool, in-kernel BTF parser as well as selftests and documentation. There are also pahole and LLVM parts: * https://github.com/iii-i/dwarves/commit/btf-kind-float-v2 * https://reviews.llvm.org/D83289 but they should go in after the libbpf part is integrated. --- v0: https://lore.kernel.org/bpf/20210210030317.78820-1-iii@linux.ibm.com/ v0 -> v1: Per Andrii's suggestion, remove the unnecessary trailing u32. v1: https://lore.kernel.org/bpf/20210216011216.3168-1-iii@linux.ibm.com/ v1 -> v2: John noticed that sanitization corrupts BTF, because new and old sizes don't match. Per Yonghong's suggestion, use a modifier type (which has the same size as the float type) as a replacement. Per Yonghong's suggestion, add size and alignment checks to the kernel BTF parser. v2: https://lore.kernel.org/bpf/20210219022543.20893-1-iii@linux.ibm.com/ v2 -> v3: Based on Yonghong's suggestions: Use BTF_KIND_CONST instead of BTF_KIND_TYPEDEF and make sure that the C code generated from the sanitized BTF is well-formed; fix size calculation in tests and use NAME_TBD everywhere; limit allowed sizes to 2, 4, 8, 12 and 16 (this should also fix m68k and nds32le builds). v3: https://lore.kernel.org/bpf/20210220034959.27006-1-iii@linux.ibm.com/ v3 -> v4: More fixes for the Yonghong's findings: fix the outdated comment in bpf_object__sanitize_btf() and add the error handling there (I've decided to check uint_id and uchar_id too in order to simplify debugging); add bpftool output example; use div64_u64_rem() instead of % in order to fix the linker error. Also fix the "invalid BTF_INFO" test (new commit, #4). Based on Alexei's feedback [1] I'm proceeding with the BTF_KIND_FLOAT approach. [1] https://lore.kernel.org/bpf/CAADnVQKWPODWZ2RSJ5FJhfYpxkuV0cvSAL1O+FSr9oP1ercoBg@mail.gmail.com/ Ilya Leoshkevich (7): bpf: Add BTF_KIND_FLOAT to uapi libbpf: Add BTF_KIND_FLOAT support tools/bpftool: Add BTF_KIND_FLOAT support selftests/bpf: Use 25th bit in "invalid BTF_INFO" test bpf: Add BTF_KIND_FLOAT support selftest/bpf: Add BTF_KIND_FLOAT tests bpf: Document BTF_KIND_FLOAT in btf.rst Documentation/bpf/btf.rst | 17 ++- include/uapi/linux/btf.h | 5 +- kernel/bpf/btf.c | 79 ++++++++++- tools/bpf/bpftool/btf.c | 8 ++ tools/bpf/bpftool/btf_dumper.c | 1 + tools/include/uapi/linux/btf.h | 5 +- tools/lib/bpf/btf.c | 44 +++++++ tools/lib/bpf/btf.h | 8 ++ tools/lib/bpf/btf_dump.c | 4 + tools/lib/bpf/libbpf.c | 84 +++++++++++- tools/lib/bpf/libbpf.map | 5 + tools/lib/bpf/libbpf_internal.h | 2 + tools/testing/selftests/bpf/btf_helpers.c | 4 + tools/testing/selftests/bpf/prog_tests/btf.c | 131 ++++++++++++++++++- tools/testing/selftests/bpf/test_btf.h | 3 + 15 files changed, 386 insertions(+), 14 deletions(-)