From patchwork Fri May 31 20:21:28 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrii Nakryiko X-Patchwork-Id: 1108569 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="qdTqioI1"; dkim-atps=neutral Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id 45FwpW3Fgtz9s9N for ; Sat, 1 Jun 2019 06:21:55 +1000 (AEST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727556AbfEaUVy (ORCPT ); Fri, 31 May 2019 16:21:54 -0400 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:51082 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727459AbfEaUVy (ORCPT ); Fri, 31 May 2019 16:21:54 -0400 Received: from pps.filterd (m0109333.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.27/8.16.0.27) with SMTP id x4VKJufp013611 for ; Fri, 31 May 2019 13:21:53 -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=Hz/uYrVBA3zsJJJt5cGiSxPJ320YZfZ02wprCUKquW8=; b=qdTqioI1rEW8LEdi1Td0NYLnYxyH7e2y/QahOC3rK0ivz4s6Yv7dN0tqr1qLVzDq8zUQ JyHEizZQsrfzxcpwF/rDQwwUrPyl09elWu8J3PMisERAgl5DpIgc4Wa/44aDLjKCFWDi jOjij1JCLi3k4xYuP747jv6+SVqZPqSkq2Q= Received: from maileast.thefacebook.com ([163.114.130.16]) by mx0a-00082601.pphosted.com with ESMTP id 2su6aa9436-3 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Fri, 31 May 2019 13:21:52 -0700 Received: from mx-out.facebook.com (2620:10d:c0a8:1b::d) by mail.thefacebook.com (2620:10d:c0a8:83::7) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.1713.5; Fri, 31 May 2019 13:21:51 -0700 Received: by dev101.prn2.facebook.com (Postfix, from userid 137359) id 9EFF8861799; Fri, 31 May 2019 13:21:49 -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 4/8] libbpf: identify maps by section index in addition to offset Date: Fri, 31 May 2019 13:21:28 -0700 Message-ID: <20190531202132.379386-5-andriin@fb.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190531202132.379386-1-andriin@fb.com> References: <20190531202132.379386-1-andriin@fb.com> X-FB-Internal: Safe MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:, , definitions=2019-05-31_14:, , signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 priorityscore=1501 malwarescore=0 suspectscore=0 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-1905310123 X-FB-Internal: deliver Sender: bpf-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org To support maps to be defined in multiple sections, it's important to identify map not just by offset within its section, but section index as well. This patch adds tracking of section index. For global data, we record section index of corresponding .data/.bss/.rodata ELF section for uniformity, and thus don't need a special value of offset for those maps. Signed-off-by: Andrii Nakryiko --- tools/lib/bpf/libbpf.c | 42 ++++++++++++++++++++++++++---------------- 1 file changed, 26 insertions(+), 16 deletions(-) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index c931ee7e1fd2..5e7ea7dac958 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -207,7 +207,8 @@ static const char * const libbpf_type_to_btf_name[] = { struct bpf_map { int fd; char *name; - size_t offset; + int sec_idx; + size_t sec_offset; int map_ifindex; int inner_map_fd; struct bpf_map_def def; @@ -647,7 +648,9 @@ static int compare_bpf_map(const void *_a, const void *_b) const struct bpf_map *a = _a; const struct bpf_map *b = _b; - return a->offset - b->offset; + if (a->sec_idx != b->sec_idx) + return a->sec_idx - b->sec_idx; + return a->sec_offset - b->sec_offset; } static bool bpf_map_type__is_map_in_map(enum bpf_map_type type) @@ -800,14 +803,15 @@ static struct bpf_map *bpf_object__add_map(struct bpf_object *obj) static int bpf_object__init_internal_map(struct bpf_object *obj, struct bpf_map *map, - enum libbpf_map_type type, Elf_Data *data, - void **data_buff) + enum libbpf_map_type type, int sec_idx, + Elf_Data *data, void **data_buff) { struct bpf_map_def *def = &map->def; char map_name[BPF_OBJ_NAME_LEN]; map->libbpf_type = type; - map->offset = ~(typeof(map->offset))0; + map->sec_idx = sec_idx; + map->sec_offset = 0; snprintf(map_name, sizeof(map_name), "%.8s%.7s", obj->name, libbpf_type_to_btf_name[type]); map->name = strdup(map_name); @@ -815,6 +819,8 @@ bpf_object__init_internal_map(struct bpf_object *obj, struct bpf_map *map, pr_warning("failed to alloc map name\n"); return -ENOMEM; } + pr_debug("map '%s' (global data): at sec_idx %d, offset %zu.\n", + map_name, map->sec_idx, map->sec_offset); def->type = BPF_MAP_TYPE_ARRAY; def->key_size = sizeof(int); @@ -850,6 +856,7 @@ static int bpf_object__init_global_data_maps(struct bpf_object *obj) if (IS_ERR(map)) return PTR_ERR(map); err = bpf_object__init_internal_map(obj, map, LIBBPF_MAP_DATA, + obj->efile.data_shndx, obj->efile.data, &obj->sections.data); if (err) @@ -860,6 +867,7 @@ static int bpf_object__init_global_data_maps(struct bpf_object *obj) if (IS_ERR(map)) return PTR_ERR(map); err = bpf_object__init_internal_map(obj, map, LIBBPF_MAP_RODATA, + obj->efile.rodata_shndx, obj->efile.rodata, &obj->sections.rodata); if (err) @@ -870,6 +878,7 @@ static int bpf_object__init_global_data_maps(struct bpf_object *obj) if (IS_ERR(map)) return PTR_ERR(map); err = bpf_object__init_internal_map(obj, map, LIBBPF_MAP_BSS, + obj->efile.bss_shndx, obj->efile.bss, NULL); if (err) return err; @@ -953,7 +962,10 @@ static int bpf_object__init_user_maps(struct bpf_object *obj, bool strict) } map->libbpf_type = LIBBPF_MAP_UNSPEC; - map->offset = sym.st_value; + map->sec_idx = sym.st_shndx; + map->sec_offset = sym.st_value; + pr_debug("map '%s' (legacy): at sec_idx %d, offset %zu.\n", + map_name, map->sec_idx, map->sec_offset); if (sym.st_value + map_def_sz > data->d_size) { pr_warning("corrupted maps section in %s: last map \"%s\" too small\n", obj->path, map_name); @@ -1453,9 +1465,13 @@ bpf_program__collect_reloc(struct bpf_program *prog, GElf_Shdr *shdr, if (maps[map_idx].libbpf_type != type) continue; if (type != LIBBPF_MAP_UNSPEC || - maps[map_idx].offset == sym.st_value) { - pr_debug("relocation: find map %zd (%s) for insn %u\n", - map_idx, maps[map_idx].name, insn_idx); + (maps[map_idx].sec_idx == sym.st_shndx && + maps[map_idx].sec_offset == sym.st_value)) { + pr_debug("relocation: found map %zd (%s, sec_idx %d, offset %zu) for insn %u\n", + map_idx, maps[map_idx].name, + maps[map_idx].sec_idx, + maps[map_idx].sec_offset, + insn_idx); break; } } @@ -3472,13 +3488,7 @@ bpf_object__find_map_fd_by_name(struct bpf_object *obj, const char *name) struct bpf_map * bpf_object__find_map_by_offset(struct bpf_object *obj, size_t offset) { - int i; - - for (i = 0; i < obj->nr_maps; i++) { - if (obj->maps[i].offset == offset) - return &obj->maps[i]; - } - return ERR_PTR(-ENOENT); + return ERR_PTR(-ENOTSUP); } long libbpf_get_error(const void *ptr)