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=-9.9 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,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 357DFC2D0CA for ; Sat, 14 Dec 2019 01:47:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 2486D2077B for ; Sat, 14 Dec 2019 01:47:25 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=fb.com header.i=@fb.com header.b="TxZeYw5y" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726668AbfLNBrY (ORCPT ); Fri, 13 Dec 2019 20:47:24 -0500 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:57726 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726774AbfLNBrY (ORCPT ); Fri, 13 Dec 2019 20:47:24 -0500 Received: from pps.filterd (m0109334.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.42/8.16.0.42) with SMTP id xBE1hbhq016462 for ; Fri, 13 Dec 2019 17:47:23 -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=x/ft1qXOaG4vbwkOlFcjZBPsiOZZ6GJQmpe9ltjq3gU=; b=TxZeYw5yFWV69mny5Fz4W3O03GnWkDrumrAriI+m3Jo56vhmaWOvyGGdS4MzhTNTwNl9 tn6WS7z/yISZvwgjHjNoG6WVgsj/IYukgL9tRxjfHVl3GUwIGSNQKNvf+Pf6psGuBZVu 1aKFk0yXWWDA2SSW/lOGQI5YzuoqavnxiwE= Received: from maileast.thefacebook.com ([163.114.130.16]) by mx0a-00082601.pphosted.com with ESMTP id 2wvm79rhd6-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Fri, 13 Dec 2019 17:47:23 -0800 Received: from intmgw003.06.prn3.facebook.com (2620:10d:c0a8:1b::d) by mail.thefacebook.com (2620:10d:c0a8:83::5) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1713.5; Fri, 13 Dec 2019 17:47:22 -0800 Received: by devbig012.ftw2.facebook.com (Postfix, from userid 137359) id D66272EC1D7C; Fri, 13 Dec 2019 17:47:18 -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 v4 bpf-next 3/4] bpftool: generate externs datasec in BPF skeleton Date: Fri, 13 Dec 2019 17:47:09 -0800 Message-ID: <20191214014710.3449601-4-andriin@fb.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20191214014710.3449601-1-andriin@fb.com> References: <20191214014710.3449601-1-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=2019-12-13_09:2019-12-13,2019-12-13 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 malwarescore=0 suspectscore=8 bulkscore=0 priorityscore=1501 mlxscore=0 impostorscore=0 clxscore=1015 spamscore=0 adultscore=0 phishscore=0 mlxlogscore=999 lowpriorityscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-1910280000 definitions=main-1912140007 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 7379dae35dca..a07c80429c7a 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 26144706ba0b..c9f90bfd2f0d 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -7472,7 +7472,8 @@ 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; } @@ -7505,7 +7506,6 @@ 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; @@ -7530,9 +7530,9 @@ 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