From patchwork Thu Mar 18 19:40:24 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrii Nakryiko X-Patchwork-Id: 404561 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=-12.0 required=3.0 tests=BAYES_00,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 E9CC9C4332E for ; Thu, 18 Mar 2021 19:41:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A7ECF64F2A for ; Thu, 18 Mar 2021 19:41:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232903AbhCRTlU convert rfc822-to-8bit (ORCPT ); Thu, 18 Mar 2021 15:41:20 -0400 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:6272 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232904AbhCRTkt (ORCPT ); Thu, 18 Mar 2021 15:40:49 -0400 Received: from pps.filterd (m0148461.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.43/8.16.0.43) with SMTP id 12IJYS7S025637 for ; Thu, 18 Mar 2021 12:40:48 -0700 Received: from maileast.thefacebook.com ([163.114.130.16]) by mx0a-00082601.pphosted.com with ESMTP id 37bs1epbqg-2 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Thu, 18 Mar 2021 12:40:48 -0700 Received: from intmgw001.37.frc1.facebook.com (2620:10d:c0a8:1b::d) by mail.thefacebook.com (2620:10d:c0a8:83::7) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Thu, 18 Mar 2021 12:40:44 -0700 Received: by devbig012.ftw2.facebook.com (Postfix, from userid 137359) id CF97A2ED2588; Thu, 18 Mar 2021 12:40:41 -0700 (PDT) From: Andrii Nakryiko To: , , , CC: , Subject: [PATCH v4 bpf-next 00/12] BPF static linking Date: Thu, 18 Mar 2021 12:40:24 -0700 Message-ID: <20210318194036.3521577-1-andrii@kernel.org> X-Mailer: git-send-email 2.30.2 MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.369, 18.0.761 definitions=2021-03-18_12:2021-03-17,2021-03-18 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 suspectscore=0 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 priorityscore=1501 mlxscore=0 adultscore=0 mlxlogscore=999 malwarescore=0 impostorscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2009150000 definitions=main-2103180139 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org This patch set adds new libbpf APIs and their bpftool integration that allows to perform static linking of BPF object files. Currently no extern resolution across object files is performed. This is going to be the focus of the follow up patches. But, given amount of code and logic necessary to perform just basic functionality of linking together mostly independent BPF object files, it was decided to land basic BPF linker code and logic first and extend it afterwards. The motivation for BPF static linking is to provide the functionality that is naturally assumed for user-space development process: ability to structure application's code without artificial restrictions of having all the code and data (variables and maps) inside a single source code file. This enables better engineering practices of splitting code into well-encapsulated parts. It provides ability to hide internal state from other parts of the code base through static variables and maps. It is also a first steps towards having generic reusable BPF libraries. Please see individual patches (mostly #6 and #7) for more details. Patch #10 passes all test_progs' individual BPF .o files through BPF static linker, which is supposed to be a no-op operation, so is essentially validating that BPF static linker doesn't produce corrupted ELF object files. Patch #11 adds Makefile infra to be able to specify multi-file BPF object files and adds the first multi-file test to validate correctness. v3->v4: - fix Makefile copy/paste error of diff'ing invalid object files (Alexei); - fix uninitialized obj_name variable that could lead to bogus object names being used during skeleton generation (kernel-patches CI); v2->v3: - added F(F(F(X))) = F(F(X)) test for all linked BPF object files (Alexei); - used reallocarray() more consistently in few places (Alexei); - improved bash completions for `gen object` (Quentin); - dropped .bpfo extension, but had to add optional `name OBJECT_FILE` parameter (path #8) to `gen skeleton` command to specify desired object name during skeleton generation; - fixed bug of merging DATASECS of special "license" and "version" sections. Linker currently strictly validates that all versions and licenses matches exactly and keeps only ELF symbols and BTF DATASEC from the very first object file with license/version. For all other object files, we ignore ELF symbols, but weren't ignoring DATASECs, which caused further problems of not being able to find a corresponding ELF symbol, if variable name differs between two files (which we test deliberately in multi-file linking selftest). The fix is to ignore BTF DATASECS; v1->v2: - extracted `struct strset` to manage unique set of strings both for BTF and ELF SYMTAB (patch #4, refactors btf and btf_dedup logic as well) (Alexei); - fixed bugs in bpftool gen command; renamed it to `gen object`, added BASH completions and extended/updated man page (Quentin). Andrii Nakryiko (12): libbpf: expose btf_type_by_id() internally libbpf: generalize BTF and BTF.ext type ID and strings iteration libbpf: rename internal memory-management helpers libbpf: extract internal set-of-strings datastructure APIs libbpf: add generic BTF type shallow copy API libbpf: add BPF static linker APIs libbpf: add BPF static linker BTF and BTF.ext support bpftool: add ability to specify custom skeleton object name bpftool: add `gen object` command to perform BPF static linking selftests/bpf: re-generate vmlinux.h and BPF skeletons if bpftool changed selftests/bpf: pass all BPF .o's through BPF static linker selftests/bpf: add multi-file statically linked BPF object file test .../bpf/bpftool/Documentation/bpftool-gen.rst | 78 +- tools/bpf/bpftool/bash-completion/bpftool | 17 +- tools/bpf/bpftool/gen.c | 72 +- tools/lib/bpf/Build | 2 +- tools/lib/bpf/btf.c | 714 +++--- tools/lib/bpf/btf.h | 2 + tools/lib/bpf/btf_dump.c | 8 +- tools/lib/bpf/libbpf.c | 15 +- tools/lib/bpf/libbpf.h | 13 + tools/lib/bpf/libbpf.map | 5 + tools/lib/bpf/libbpf_internal.h | 38 +- tools/lib/bpf/linker.c | 1941 +++++++++++++++++ tools/lib/bpf/strset.c | 176 ++ tools/lib/bpf/strset.h | 21 + tools/testing/selftests/bpf/Makefile | 27 +- .../selftests/bpf/prog_tests/static_linked.c | 40 + .../selftests/bpf/progs/test_static_linked1.c | 30 + .../selftests/bpf/progs/test_static_linked2.c | 31 + 18 files changed, 2806 insertions(+), 424 deletions(-) create mode 100644 tools/lib/bpf/linker.c create mode 100644 tools/lib/bpf/strset.c create mode 100644 tools/lib/bpf/strset.h create mode 100644 tools/testing/selftests/bpf/prog_tests/static_linked.c create mode 100644 tools/testing/selftests/bpf/progs/test_static_linked1.c create mode 100644 tools/testing/selftests/bpf/progs/test_static_linked2.c