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=-3.9 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=no 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 0F588C10F14 for ; Tue, 8 Oct 2019 19:46:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D664621835 for ; Tue, 8 Oct 2019 19:45:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fb.com header.i=@fb.com header.b="IXOBO9jk" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730156AbfJHTp7 (ORCPT ); Tue, 8 Oct 2019 15:45:59 -0400 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:31958 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729647AbfJHTp7 (ORCPT ); Tue, 8 Oct 2019 15:45:59 -0400 Received: from pps.filterd (m0109333.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id x98Jj5Wr013380 for ; Tue, 8 Oct 2019 12:45:58 -0700 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=4ZqodNMNzZghFxCeYdYkqXUZ3wwf06nIFSa1OQsT53g=; b=IXOBO9jkEoF6ka4d5hBoZ2HKkIOEwCTZvk+F1pa401KYFSD4kegYH53vipq/Prvb0CRf HHHPOg7CnYL2hf6xLvtS7TJiizKUSnoxcGH9gcTiBbJkBMfJSJTn/U10vO7vyRYB94Z4 nlP5nnIUw7faVhsp+YGS8kR/1C+tuEYyyG4= Received: from maileast.thefacebook.com ([163.114.130.16]) by mx0a-00082601.pphosted.com with ESMTP id 2vgvc7swvv-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Tue, 08 Oct 2019 12:45:58 -0700 Received: from 2401:db00:30:6007:face:0:1:0 (2620:10d:c0a8:1b::d) by mail.thefacebook.com (2620:10d:c0a8:82::f) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1713.5; Tue, 8 Oct 2019 12:45:57 -0700 Received: by dev101.prn2.facebook.com (Postfix, from userid 137359) id 78B1E8618E0; Tue, 8 Oct 2019 12:45:56 -0700 (PDT) Smtp-Origin-Hostprefix: dev From: Andrii Nakryiko Smtp-Origin-Hostname: dev101.prn2.facebook.com To: , , , CC: , , Andrii Nakryiko Smtp-Origin-Cluster: prn2c23 Subject: [PATCH bpf-next 0/2] Track read-only map contents as known scalars in BPF verifiers Date: Tue, 8 Oct 2019 12:45:46 -0700 Message-ID: <20191008194548.2344473-1-andriin@fb.com> X-Mailer: git-send-email 2.17.1 X-FB-Internal: Safe MIME-Version: 1.0 Content-Type: text/plain X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.95,1.0.8 definitions=2019-10-08_07:2019-10-08,2019-10-08 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 mlxscore=0 malwarescore=0 phishscore=0 adultscore=0 clxscore=1015 priorityscore=1501 bulkscore=0 mlxlogscore=694 impostorscore=0 lowpriorityscore=0 spamscore=0 suspectscore=8 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-1908290000 definitions=main-1910080151 X-FB-Internal: deliver Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org With BPF maps supporting direct map access (currently, array_map w/ single element, used for global data) that are read-only both from system call and BPF side, it's possible for BPF verifier to track its contents as known constants. Now it's possible for user-space control app to pre-initialize read-only map (e.g., for .rodata section) with user-provided flags and parameters and rely on BPF verifier to detect and eliminate dead code resulting from specific combination of input parameters. Andrii Nakryiko (2): bpf: track contents of read-only maps as scalars selftests/bpf: add read-only map values propagation tests kernel/bpf/verifier.c | 58 ++++++++++- .../selftests/bpf/prog_tests/rdonly_maps.c | 99 +++++++++++++++++++ .../selftests/bpf/progs/test_rdonly_maps.c | 83 ++++++++++++++++ 3 files changed, 238 insertions(+), 2 deletions(-) create mode 100644 tools/testing/selftests/bpf/prog_tests/rdonly_maps.c create mode 100644 tools/testing/selftests/bpf/progs/test_rdonly_maps.c -- 2.17.1