From patchwork Tue Jun 11 04:35:02 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrii Nakryiko X-Patchwork-Id: 1113437 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Original-To: incoming-bpf@patchwork.ozlabs.org Delivered-To: patchwork-incoming-bpf@bilbo.ozlabs.org Authentication-Results: ozlabs.org; spf=none (mailfrom) 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="howp55/R"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 45NHHH6Vx6z9s4Y for ; Tue, 11 Jun 2019 14:35:23 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391022AbfFKEfW (ORCPT ); Tue, 11 Jun 2019 00:35:22 -0400 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:45856 "EHLO mx0b-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390985AbfFKEfW (ORCPT ); Tue, 11 Jun 2019 00:35:22 -0400 Received: from pps.filterd (m0148460.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x5B4XbxH001561 for ; Mon, 10 Jun 2019 21:35:20 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-type; s=facebook; bh=AYJBxbod3aKifNwgTVgPBUcBvNE6JScxe741jkomWoE=; b=howp55/RMuHo20oJ6XeLKMEBSk/3EIoDYv1OWMVmho9TzlSIBfvnQ+IicNltI/MoxVnT 3XpkQTEIqONdSiOtqkWF5ino7hmORzli9nqCm3GvbafzVd7Oakq4hiSd+zpGTtpiyXca +gRaCXRBWyi+2e2GRDWhGiQOI1PBAzGUBjQ= Received: from mail.thefacebook.com (mailout.thefacebook.com [199.201.64.23]) by mx0a-00082601.pphosted.com with ESMTP id 2t2480g5nr-3 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-SHA384 bits=256 verify=NOT) for ; Mon, 10 Jun 2019 21:35:20 -0700 Received: from mx-out.facebook.com (2620:10d:c081:10::13) by mail.thefacebook.com (2620:10d:c081:35::130) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA) id 15.1.1713.5; Mon, 10 Jun 2019 21:35:19 -0700 Received: by dev101.prn2.facebook.com (Postfix, from userid 137359) id EE7B386184B; Mon, 10 Jun 2019 21:35:18 -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: [RFC PATCH bpf-next 5/8] libbpf: split initialization and loading of BTF Date: Mon, 10 Jun 2019 21:35:02 -0700 Message-ID: <20190611043505.14664-6-andriin@fb.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190611043505.14664-1-andriin@fb.com> References: <20190611043505.14664-1-andriin@fb.com> X-FB-Internal: Safe MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:, , definitions=2019-06-11_02:, , signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 priorityscore=1501 malwarescore=0 suspectscore=2 phishscore=0 bulkscore=0 spamscore=0 clxscore=1015 lowpriorityscore=0 mlxscore=0 impostorscore=0 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.0.1-1810050000 definitions=main-1906110031 X-FB-Internal: deliver Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Libbpf does sanitization of BTF before loading it into kernel, if kernel doesn't support some of newer BTF features. This removes some of the important information from BTF (e.g., DATASEC and VAR description), which will be used for map construction. This patch splits BTF processing into initialization step, in which BTF is initialized from ELF and all the original data is still preserved; and sanitization/loading step, which ensures that BTF is safe to load into kernel. This allows to use full BTF information to construct maps, while still loading valid BTF into older kernels. Signed-off-by: Andrii Nakryiko --- tools/lib/bpf/libbpf.c | 34 ++++++++++++++++++++++++---------- 1 file changed, 24 insertions(+), 10 deletions(-) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 5e7ea7dac958..79a8143240d7 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -1118,7 +1118,7 @@ static void bpf_object__sanitize_btf_ext(struct bpf_object *obj) } } -static int bpf_object__load_btf(struct bpf_object *obj, +static int bpf_object__init_btf(struct bpf_object *obj, Elf_Data *btf_data, Elf_Data *btf_ext_data) { @@ -1137,13 +1137,6 @@ static int bpf_object__load_btf(struct bpf_object *obj, BTF_ELF_SEC, err); goto out; } - bpf_object__sanitize_btf(obj); - err = btf__load(obj->btf); - if (err) { - pr_warning("Error loading %s into kernel: %d.\n", - BTF_ELF_SEC, err); - goto out; - } } if (btf_ext_data) { if (!obj->btf) { @@ -1159,7 +1152,6 @@ static int bpf_object__load_btf(struct bpf_object *obj, obj->btf_ext = NULL; goto out; } - bpf_object__sanitize_btf_ext(obj); } out: if (err || IS_ERR(obj->btf)) { @@ -1170,6 +1162,26 @@ static int bpf_object__load_btf(struct bpf_object *obj, return 0; } +static int bpf_object__sanitize_and_load_btf(struct bpf_object *obj) +{ + int err = 0; + + if (!obj->btf) + return 0; + + bpf_object__sanitize_btf(obj); + bpf_object__sanitize_btf_ext(obj); + + err = btf__load(obj->btf); + if (err) { + pr_warning("Error loading %s into kernel: %d.\n", + BTF_ELF_SEC, err); + btf__free(obj->btf); + obj->btf = NULL; + } + return 0; +} + static int bpf_object__elf_collect(struct bpf_object *obj, int flags) { Elf *elf = obj->efile.elf; @@ -1301,9 +1313,11 @@ static int bpf_object__elf_collect(struct bpf_object *obj, int flags) pr_warning("Corrupted ELF file: index of strtab invalid\n"); return -LIBBPF_ERRNO__FORMAT; } - err = bpf_object__load_btf(obj, btf_data, btf_ext_data); + err = bpf_object__init_btf(obj, btf_data, btf_ext_data); if (!err) err = bpf_object__init_maps(obj, flags); + if (!err) + err = bpf_object__sanitize_and_load_btf(obj); if (!err) err = bpf_object__init_prog_names(obj); return err;