From patchwork Thu Apr 22 01:45:53 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrii Nakryiko X-Patchwork-Id: 426209 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=-17.0 required=3.0 tests=BAYES_00, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=unavailable 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 56CD9C43600 for ; Thu, 22 Apr 2021 01:46:19 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 38D8561435 for ; Thu, 22 Apr 2021 01:46:19 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234342AbhDVBqw convert rfc822-to-8bit (ORCPT ); Wed, 21 Apr 2021 21:46:52 -0400 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:26432 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S234235AbhDVBqr (ORCPT ); Wed, 21 Apr 2021 21:46:47 -0400 Received: from pps.filterd (m0001303.ppops.net [127.0.0.1]) by m0001303.ppops.net (8.16.0.43/8.16.0.43) with SMTP id 13M1h5nY023371 for ; Wed, 21 Apr 2021 18:46:12 -0700 Received: from mail.thefacebook.com ([163.114.132.120]) by m0001303.ppops.net with ESMTP id 38270e08tf-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Wed, 21 Apr 2021 18:46:12 -0700 Received: from intmgw001.37.frc1.facebook.com (2620:10d:c085:108::4) by mail.thefacebook.com (2620:10d:c085:11d::6) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Wed, 21 Apr 2021 18:46:11 -0700 Received: by devbig012.ftw2.facebook.com (Postfix, from userid 137359) id BE80E2ED59F8; Wed, 21 Apr 2021 18:46:04 -0700 (PDT) From: Andrii Nakryiko To: , , , CC: , Subject: [PATCH bpf-next 3/6] libbpf: support static map definitions Date: Wed, 21 Apr 2021 18:45:53 -0700 Message-ID: <20210422014556.3451936-4-andrii@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210422014556.3451936-1-andrii@kernel.org> References: <20210422014556.3451936-1-andrii@kernel.org> MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-ORIG-GUID: fSc8HH1yJBOzoCswChukYhz_twMDOWls X-Proofpoint-GUID: fSc8HH1yJBOzoCswChukYhz_twMDOWls X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.391, 18.0.761 definitions=2021-04-21_08:2021-04-21,2021-04-21 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 priorityscore=1501 lowpriorityscore=0 bulkscore=0 spamscore=0 impostorscore=0 mlxlogscore=994 phishscore=0 suspectscore=0 malwarescore=0 mlxscore=0 adultscore=0 clxscore=1015 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2104060000 definitions=main-2104220014 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Change libbpf relocation logic to support references to static map definitions. This allows to use static maps and, combined with static linking, hide internal maps from other files, just like static variables. User-space will still be able to look up and modify static maps. Signed-off-by: Andrii Nakryiko --- tools/lib/bpf/libbpf.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 82b1946a0802..a7c3bcb8e5ea 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -3632,6 +3632,8 @@ static int bpf_program__record_reloc(struct bpf_program *prog, /* generic map reference relocation */ if (type == LIBBPF_MAP_UNSPEC) { + size_t map_offset = sym->st_value + insn->imm; + if (!bpf_object__shndx_is_maps(obj, shdr_idx)) { pr_warn("prog '%s': bad map relo against '%s' in section '%s'\n", prog->name, sym_name, sym_sec_name); @@ -3641,7 +3643,7 @@ static int bpf_program__record_reloc(struct bpf_program *prog, map = &obj->maps[map_idx]; if (map->libbpf_type != type || map->sec_idx != sym->st_shndx || - map->sec_offset != sym->st_value) + map->sec_offset != map_offset) continue; pr_debug("prog '%s': found map %zd (%s, sec %d, off %zu) for insn #%u\n", prog->name, map_idx, map->name, map->sec_idx, @@ -3656,7 +3658,8 @@ static int bpf_program__record_reloc(struct bpf_program *prog, reloc_desc->type = RELO_LD64; reloc_desc->insn_idx = insn_idx; reloc_desc->map_idx = map_idx; - reloc_desc->sym_off = 0; /* sym->st_value determines map_idx */ + /* sym->st_value + insn->imm determines map_idx */ + reloc_desc->sym_off = 0; return 0; }