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=-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 100F1C433EF for ; Mon, 13 Sep 2021 15:51:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E51E360555 for ; Mon, 13 Sep 2021 15:51:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245243AbhIMPwv (ORCPT ); Mon, 13 Sep 2021 11:52:51 -0400 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:47780 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S245366AbhIMPwm (ORCPT ); Mon, 13 Sep 2021 11:52:42 -0400 Received: from pps.filterd (m0001303.ppops.net [127.0.0.1]) by m0001303.ppops.net (8.16.1.2/8.16.0.43) with SMTP id 18DF4LbB025505 for ; Mon, 13 Sep 2021 08:51:25 -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=KS8f6Q6ixnmoOVZg3nFdHUHQEapbW318b/XHh06i90s=; b=dPNmqipWetqJ3WPDLyJtHWDamzdshdoS3Exm6MQrNaGBt1TErPBOotTp6Pure1k39pRt Qz16FqsJebmb0+GcS/As+dTo75V//k7BXi2fbJ5TUsMeD7ODy5P6ZzZuZ+xcmWPYdeoF gGakuDub9Qdo8G55oLE+qsecUXQmW0gwONc= Received: from maileast.thefacebook.com ([163.114.130.16]) by m0001303.ppops.net with ESMTP id 3b215pjw0r-3 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Mon, 13 Sep 2021 08:51:25 -0700 Received: from intmgw001.25.frc3.facebook.com (2620:10d:c0a8:1b::d) by mail.thefacebook.com (2620:10d:c0a8:82::c) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.14; Mon, 13 Sep 2021 08:51:23 -0700 Received: by devbig003.ftw2.facebook.com (Postfix, from userid 128203) id 8681C7278F1B; Mon, 13 Sep 2021 08:51:22 -0700 (PDT) From: Yonghong Song To: CC: Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , Subject: [PATCH bpf-next v2 00/11] bpf: add support for new btf kind BTF_KIND_TAG Date: Mon, 13 Sep 2021 08:51:22 -0700 Message-ID: <20210913155122.3722704-1-yhs@fb.com> X-Mailer: git-send-email 2.30.2 X-FB-Internal: Safe Content-Type: text/plain X-FB-Source: Intern X-Proofpoint-GUID: IeiF2UAbDBdcwEixIDHjaDLz_ar6YrdU X-Proofpoint-ORIG-GUID: IeiF2UAbDBdcwEixIDHjaDLz_ar6YrdU Content-Transfer-Encoding: quoted-printable X-Proofpoint-UnRewURL: 0 URL was un-rewritten MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.182.1,Aquarius:18.0.790,Hydra:6.0.391,FMLib:17.0.607.475 definitions=2021-09-13_07,2021-09-09_01,2020-04-07_01 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 malwarescore=0 mlxlogscore=859 spamscore=0 bulkscore=0 impostorscore=0 adultscore=0 suspectscore=0 mlxscore=0 priorityscore=1501 clxscore=1015 lowpriorityscore=0 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2109030001 definitions=main-2109130103 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org 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], [4]). 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, Patches 1-2 had kernel support. Patches 3-4 added libbpf support. Patch 5 added bpftool support. Patches 6-10 added various selftests. Patch 11 added documentation for the new kind. [1] https://reviews.llvm.org/D106614 [2] https://reviews.llvm.org/D106621 [3] https://reviews.llvm.org/D106622 [4] https://reviews.llvm.org/D109560 Changelog: v1 -> v2: - BTF ELF format changed in llvm ([4] above), so cross-board change to use the new format. - Clarified in commit message that BTF_KIND_TAG is not emitted by bpftool btf dump format c. - Fix various comments from Andrii. Yonghong Song (11): btf: change BTF_KIND_* macros to enums 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: change NAME_NTH/IS_NAME_NTH for BTF_KIND_TAG format 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 | 27 +- include/uapi/linux/btf.h | 52 +-- kernel/bpf/btf.c | 120 +++++++ tools/bpf/bpftool/btf.c | 12 + tools/include/uapi/linux/btf.h | 52 +-- tools/lib/bpf/btf.c | 85 ++++- tools/lib/bpf/btf.h | 15 + tools/lib/bpf/btf_dump.c | 3 + tools/lib/bpf/libbpf.c | 31 +- tools/lib/bpf/libbpf.map | 5 + tools/lib/bpf/libbpf_internal.h | 2 + tools/testing/selftests/bpf/btf_helpers.c | 7 +- tools/testing/selftests/bpf/prog_tests/btf.c | 318 ++++++++++++++++-- .../selftests/bpf/prog_tests/btf_tag.c | 14 + .../selftests/bpf/prog_tests/btf_write.c | 21 ++ tools/testing/selftests/bpf/progs/tag.c | 39 +++ tools/testing/selftests/bpf/test_btf.h | 3 + 17 files changed, 736 insertions(+), 70 deletions(-) create mode 100644 tools/testing/selftests/bpf/prog_tests/btf_tag.c create mode 100644 tools/testing/selftests/bpf/progs/tag.c --=20 2.30.2