From patchwork Sun Dec 15 07:08:42 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrii Nakryiko X-Patchwork-Id: 1209850 Return-Path: X-Original-To: incoming-bpf@patchwork.ozlabs.org Delivered-To: patchwork-incoming-bpf@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (no SPF record) smtp.mailfrom=vger.kernel.org (client-ip=209.132.180.67; helo=vger.kernel.org; envelope-from=bpf-owner@vger.kernel.org; receiver=) Authentication-Results: ozlabs.org; dmarc=pass (p=none dis=none) header.from=fb.com Authentication-Results: ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=fb.com header.i=@fb.com header.b="eCgWoUjP"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 47bFr60xRYz9sP6 for ; Sun, 15 Dec 2019 18:08:53 +1100 (AEDT) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1725861AbfLOHIu (ORCPT ); Sun, 15 Dec 2019 02:08:50 -0500 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:57120 "EHLO mx0b-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725827AbfLOHIu (ORCPT ); Sun, 15 Dec 2019 02:08:50 -0500 Received: from pps.filterd (m0109332.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id xBF753qO031158 for ; Sat, 14 Dec 2019 23:08:49 -0800 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : mime-version : content-type; s=facebook; bh=kHZMS/PwvMTKOTlmmhL8ngUxDS3HYRtf2MSxDrn7VaE=; b=eCgWoUjPOiRHVCNo+XbjEcG3kAUKTCRC1fRHAx9YwGmyqSJ0uAiDAZRSJJAWlxvxX3KB Nb2lDUx9v4lW+pWPg3wbewoKMriXHmpd3aF6bfinWvbF7K5lbKk89DAuTlHB7mEaJbEa UNH5rv+jjWgHv6vGJbGUsVplRpOYUmiKw10= Received: from mail.thefacebook.com (mailout.thefacebook.com [199.201.64.23]) by mx0a-00082601.pphosted.com with ESMTP id 2wvxbvag6y-2 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-SHA384 bits=256 verify=NOT) for ; Sat, 14 Dec 2019 23:08:49 -0800 Received: from intmgw004.05.ash5.facebook.com (2620:10d:c081:10::13) by mail.thefacebook.com (2620:10d:c081:35::128) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA) id 15.1.1713.5; Sat, 14 Dec 2019 23:08:47 -0800 Received: by devbig012.ftw2.facebook.com (Postfix, from userid 137359) id 042182EC1683; Sat, 14 Dec 2019 23:08:46 -0800 (PST) Smtp-Origin-Hostprefix: devbig From: Andrii Nakryiko Smtp-Origin-Hostname: devbig012.ftw2.facebook.com To: , , , CC: , , Andrii Nakryiko Smtp-Origin-Cluster: ftw2c04 Subject: [PATCH bpf-next 0/2] CO-RE relocation support for flexible arrays Date: Sat, 14 Dec 2019 23:08:42 -0800 Message-ID: <20191215070844.1014385-1-andriin@fb.com> X-Mailer: git-send-email 2.17.1 X-FB-Internal: Safe MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.95, 18.0.572 definitions=2019-12-15_01:2019-12-13, 2019-12-15 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 bulkscore=0 phishscore=0 malwarescore=0 suspectscore=8 lowpriorityscore=0 mlxlogscore=595 mlxscore=0 spamscore=0 adultscore=0 clxscore=1015 priorityscore=1501 impostorscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-1910280000 definitions=main-1912150066 X-FB-Internal: deliver Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Add support for flexible array accesses in a relocatable manner in BPF CO-RE. It's a typical pattern in C, and kernel in particular, to provide a fixed-length struct with zero-sized or dimensionless array at the end. In such cases variable-sized array contents follows immediately after the end of a struct. This patch set adds support for such access pattern by allowing accesses to such arrays. Patch #1 adds libbpf support. Patch #2 adds few test cases for validation. Andrii Nakryiko (2): libbpf: support flexible arrays in CO-RE selftests/bpf: add flexible array relocation tests tools/lib/bpf/libbpf.c | 34 +++++++++++++--- .../selftests/bpf/prog_tests/core_reloc.c | 4 ++ ...f__core_reloc_arrays___equiv_zero_sz_arr.c | 3 ++ ..._core_reloc_arrays___err_bad_zero_sz_arr.c | 3 ++ .../btf__core_reloc_arrays___fixed_arr.c | 3 ++ .../selftests/bpf/progs/core_reloc_types.h | 39 +++++++++++++++++++ .../bpf/progs/test_core_reloc_arrays.c | 8 ++-- 7 files changed, 85 insertions(+), 9 deletions(-) create mode 100644 tools/testing/selftests/bpf/progs/btf__core_reloc_arrays___equiv_zero_sz_arr.c create mode 100644 tools/testing/selftests/bpf/progs/btf__core_reloc_arrays___err_bad_zero_sz_arr.c create mode 100644 tools/testing/selftests/bpf/progs/btf__core_reloc_arrays___fixed_arr.c