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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,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 64E5FC2D0C4 for ; Wed, 11 Dec 2019 06:50:36 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 30CFD214AF for ; Wed, 11 Dec 2019 06:50:36 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fb.com header.i=@fb.com header.b="MvYa+DMh" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727851AbfLKGuY (ORCPT ); Wed, 11 Dec 2019 01:50:24 -0500 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:47704 "EHLO mx0b-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727796AbfLKGuY (ORCPT ); Wed, 11 Dec 2019 01:50:24 -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 xBB6oLRn011402 for ; Tue, 10 Dec 2019 22:50:22 -0800 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=3QFm4hGtsLP7Bvs82g3Rl4rViw0PjNvbSI+gFrrxaIQ=; b=MvYa+DMhmVcgJrPQXQ59LbqXYvWf0xm/v/ZDWSHRw58CBsiVvTPx15uGDlCcIMxM4Dti oWvl0+V0WlwAeZQGQ3wGJpWIe+fEQAu68bZ43Osct0Sddj/Hfunpr/Ib48NRCIOOgC1f kj+Ucase/AZysUiaaEPVU1C/mNgACyp+A9c= Received: from mail.thefacebook.com (mailout.thefacebook.com [199.201.64.23]) by mx0a-00082601.pphosted.com with ESMTP id 2wt831dks6-4 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-SHA384 bits=256 verify=NOT) for ; Tue, 10 Dec 2019 22:50:22 -0800 Received: from intmgw002.41.prn1.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; Tue, 10 Dec 2019 22:50:10 -0800 Received: by devbig012.ftw2.facebook.com (Postfix, from userid 137359) id 6E9342EC194D; Tue, 10 Dec 2019 22:50:10 -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 v2 bpf-next 2/3] bpftool: generate externs datasec in BPF skeleton Date: Tue, 10 Dec 2019 22:50:01 -0800 Message-ID: <20191211065002.2074074-3-andriin@fb.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20191211065002.2074074-1-andriin@fb.com> References: <20191211065002.2074074-1-andriin@fb.com> X-FB-Internal: Safe MIME-Version: 1.0 Content-Type: text/plain X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.95,18.0.572 definitions=2019-12-11_01:2019-12-10,2019-12-11 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 spamscore=0 clxscore=1015 mlxscore=0 impostorscore=0 suspectscore=8 malwarescore=0 adultscore=0 lowpriorityscore=0 phishscore=0 mlxlogscore=999 bulkscore=0 priorityscore=1501 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-1910280000 definitions=main-1912110058 X-FB-Internal: deliver Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org Add support for generation of mmap()-ed read-only view of libbpf-provided extern variables. As externs are not supposed to be provided by user code (that's what .data, .bss, and .rodata is for), don't mmap() it initially. Only after skeleton load is performed, map .extern contents as read-only memory. Signed-off-by: Andrii Nakryiko --- tools/bpf/bpftool/gen.c | 4 ++++ tools/lib/bpf/libbpf.c | 10 +++++----- 2 files changed, 9 insertions(+), 5 deletions(-) diff --git a/tools/bpf/bpftool/gen.c b/tools/bpf/bpftool/gen.c index ea2cb251af94..9b8b9c228c85 100644 --- a/tools/bpf/bpftool/gen.c +++ b/tools/bpf/bpftool/gen.c @@ -82,6 +82,8 @@ static const char *get_map_ident(const struct bpf_map *map) return "rodata"; else if (str_has_suffix(name, ".bss")) return "bss"; + else if (str_has_suffix(name, ".extern")) + return "externs"; /* extern is a C keyword */ else return NULL; } @@ -109,6 +111,8 @@ static int codegen_datasec_def(struct bpf_object *obj, sec_ident = "bss"; else if (strcmp(sec_name, ".rodata") == 0) sec_ident = "rodata"; + else if (strcmp(sec_name, ".extern") == 0) + sec_ident = "externs"; /* extern is a C keyword */ else return 0; diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 36b82463b467..7f3c1306faee 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -7392,7 +7392,8 @@ int bpf_object__open_skeleton(struct bpf_object_skeleton *s, return -ESRCH; } - if (mmaped) + /* externs shouldn't be pre-setup from user code */ + if (mmaped && (*map)->libbpf_type != LIBBPF_MAP_EXTERN) *mmaped = (*map)->mmaped; } @@ -7425,7 +7426,6 @@ int bpf_object__load_skeleton(struct bpf_object_skeleton *s) size_t mmap_sz = bpf_map_mmap_sz(map); int prot, map_fd = bpf_map__fd(map); void **mmaped = s->maps[i].mmaped; - void *remapped; if (!mmaped) continue; @@ -7450,9 +7450,9 @@ int bpf_object__load_skeleton(struct bpf_object_skeleton *s) * as per normal clean up procedure, so we don't need to worry * about it from skeleton's clean up perspective. */ - remapped = mmap(*mmaped, mmap_sz, prot, MAP_SHARED | MAP_FIXED, - map_fd, 0); - if (remapped == MAP_FAILED) { + *mmaped = mmap(map->mmaped, mmap_sz, prot, + MAP_SHARED | MAP_FIXED, map_fd, 0); + if (*mmaped == MAP_FAILED) { err = -errno; *mmaped = NULL; pr_warn("failed to re-mmap() map '%s': %d\n", -- 2.17.1