From patchwork Tue Sep 7 23:00:49 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yonghong Song X-Patchwork-Id: 12479553 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=-14.1 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, 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 289CFC433F5 for ; Tue, 7 Sep 2021 23:01:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0F26E60C3E for ; Tue, 7 Sep 2021 23:01:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229522AbhIGXCF (ORCPT ); Tue, 7 Sep 2021 19:02:05 -0400 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:49252 "EHLO mx0b-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1347179AbhIGXCE (ORCPT ); Tue, 7 Sep 2021 19:02:04 -0400 Received: from pps.filterd (m0109332.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.43/8.16.0.43) with SMTP id 187N0a2T013609 for ; Tue, 7 Sep 2021 16:00:57 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : content-type : content-transfer-encoding : mime-version; s=facebook; bh=/eZ5kR0uSmkHCJRofC3ZT7ZAv1VQ/7MufA8qXSIfSRA=; b=bXXlBc+I8Vzv2cPNZpDi0YSaEEejEgmNViI1c6F0K1RiQUtg0vpSIYc03tKx/6/SLz4l VEzqICpjLYrLvv7zzXqYUOqoV46Uf4SCSo16IJtADXtNvn+mR0/63A4zZ/niHvR+K2tv jtujcJF72kuM9nUh+aO6w1Qwj35YWwb+bbI= Received: from mail.thefacebook.com ([163.114.132.120]) by mx0a-00082601.pphosted.com with ESMTP id 3axcqfj7xh-2 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Tue, 07 Sep 2021 16:00:57 -0700 Received: from intmgw001.38.frc1.facebook.com (2620:10d:c085:208::11) by mail.thefacebook.com (2620:10d:c085:21d::4) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.14; Tue, 7 Sep 2021 16:00:55 -0700 Received: by devbig003.ftw2.facebook.com (Postfix, from userid 128203) id 0E4A76E0C022; Tue, 7 Sep 2021 16:00:50 -0700 (PDT) From: Yonghong Song To: CC: Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , Subject: [PATCH bpf-next 0/9] bpf: add support for new btf kind BTF_KIND_TAG Date: Tue, 7 Sep 2021 16:00:49 -0700 Message-ID: <20210907230050.1957493-1-yhs@fb.com> X-Mailer: git-send-email 2.30.2 X-FB-Internal: Safe X-FB-Source: Intern X-Proofpoint-ORIG-GUID: vH0BFktLVBqHTNLhgXsQQIGwYW_gakg4 X-Proofpoint-GUID: vH0BFktLVBqHTNLhgXsQQIGwYW_gakg4 X-Proofpoint-UnRewURL: 0 URL was un-rewritten MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.391,18.0.790 definitions=2021-09-07_08:2021-09-07,2021-09-07 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 mlxscore=0 adultscore=0 suspectscore=0 phishscore=0 lowpriorityscore=0 malwarescore=0 priorityscore=1501 impostorscore=0 spamscore=0 clxscore=1015 mlxlogscore=693 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2109030001 definitions=main-2109070145 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net LLVM14 added support for a new C attribute ([1]) __attribute__((btf_tag("arbitrary_str"))) This attribute will be emitted to dwarf ([2]) and pahole will convert it to BTF. Or for bpf target, this attribute will be emitted to BTF directly ([3]). The attribute is intended to provide additional information for - struct/union type or struct/union member - static/global variables - static/global function or function parameter. This new attribute can be used to add attributes to kernel codes, e.g., pre- or post- conditions, allow/deny info, or any other info in which only the kernel is interested. Such attributes will be processed by clang frontend and emitted to dwarf, converting to BTF by pahole. Ultimiately the verifier can use these information for verification purpose. The new attribute can also be used for bpf programs, e.g., tagging with __user attributes for function parameters, specifying global function preconditions, etc. Such information may help verifier to detect user program bugs. After this series, pahole dwarf->btf converter will be enhanced to support new llvm tag for btf_tag attribute. With pahole support, we will then try to add a few real use case, e.g., __user/__rcu tagging, allow/deny list, some kernel function precondition, etc, in the kernel. In the rest of the series, Patch 1 had kernel support. Patches 2-3 added libbpf support. Patch 4 added bpftool support. Patch 5-8 added various selftests. Patch 9 added documentation for the new kind. [1] https://reviews.llvm.org/D106614 [2] https://reviews.llvm.org/D106621 [3] https://reviews.llvm.org/D106622 Yonghong Song (9): bpf: support for new btf kind BTF_KIND_TAG libbpf: rename btf_{hash,equal}_int to btf_{hash,equal}_int_tag libbpf: add support for BTF_KIND_TAG bpftool: add support for BTF_KIND_TAG selftests/bpf: test libbpf API function btf__add_tag() selftests/bpf: add BTF_KIND_TAG unit tests selftests/bpf: test BTF_KIND_TAG for deduplication selftests/bpf: add a test with a bpf program with btf_tag attributes docs/bpf: add documentation for BTF_KIND_TAG Documentation/bpf/btf.rst | 30 +- include/uapi/linux/btf.h | 15 +- kernel/bpf/btf.c | 115 +++++++ tools/bpf/bpftool/btf.c | 18 + tools/include/uapi/linux/btf.h | 15 +- tools/lib/bpf/btf.c | 77 ++++- tools/lib/bpf/btf.h | 13 + tools/lib/bpf/btf_dump.c | 3 + tools/lib/bpf/libbpf.c | 31 +- tools/lib/bpf/libbpf.map | 1 + tools/lib/bpf/libbpf_internal.h | 2 + tools/testing/selftests/bpf/btf_helpers.c | 7 +- tools/testing/selftests/bpf/prog_tests/btf.c | 314 +++++++++++++++++- .../selftests/bpf/prog_tests/btf_tag.c | 14 + .../selftests/bpf/prog_tests/btf_write.c | 23 ++ tools/testing/selftests/bpf/progs/tag.c | 39 +++ tools/testing/selftests/bpf/test_btf.h | 6 + 17 files changed, 686 insertions(+), 37 deletions(-) create mode 100644 tools/testing/selftests/bpf/prog_tests/btf_tag.c create mode 100644 tools/testing/selftests/bpf/progs/tag.c