From patchwork Fri Apr 16 20:23:48 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrii Nakryiko X-Patchwork-Id: 12208711 X-Patchwork-Delegate: bpf@iogearbox.net 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=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 80937C433ED for ; Fri, 16 Apr 2021 20:24:16 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4FE34613CE for ; Fri, 16 Apr 2021 20:24:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245560AbhDPUYk convert rfc822-to-8bit (ORCPT ); Fri, 16 Apr 2021 16:24:40 -0400 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:35430 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245434AbhDPUYi (ORCPT ); Fri, 16 Apr 2021 16:24:38 -0400 Received: from pps.filterd (m0148461.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.43/8.16.0.43) with SMTP id 13GKJ9vo020367 for ; Fri, 16 Apr 2021 13:24:13 -0700 Received: from maileast.thefacebook.com ([163.114.130.16]) by mx0a-00082601.pphosted.com with ESMTP id 37y6tykqj6-3 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Fri, 16 Apr 2021 13:24:13 -0700 Received: from intmgw006.03.ash8.facebook.com (2620:10d:c0a8:1b::d) by mail.thefacebook.com (2620:10d:c0a8:82::f) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Fri, 16 Apr 2021 13:24:11 -0700 Received: by devbig012.ftw2.facebook.com (Postfix, from userid 137359) id 330632ED4EE0; Fri, 16 Apr 2021 13:24:07 -0700 (PDT) From: Andrii Nakryiko To: , , , CC: , Subject: [PATCH v2 bpf-next 01/17] bpftool: support dumping BTF VAR's "extern" linkage Date: Fri, 16 Apr 2021 13:23:48 -0700 Message-ID: <20210416202404.3443623-2-andrii@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210416202404.3443623-1-andrii@kernel.org> References: <20210416202404.3443623-1-andrii@kernel.org> MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-ORIG-GUID: 81h59ozKE2_-7isHVaFV-xxm40efoStI X-Proofpoint-GUID: 81h59ozKE2_-7isHVaFV-xxm40efoStI X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.391,18.0.761 definitions=2021-04-16_09:2021-04-16,2021-04-16 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 clxscore=1015 priorityscore=1501 malwarescore=0 bulkscore=0 adultscore=0 lowpriorityscore=0 mlxlogscore=952 mlxscore=0 phishscore=0 suspectscore=0 impostorscore=0 spamscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2104060000 definitions=main-2104160143 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net Add dumping of "extern" linkage for BTF VAR kind. Also shorten "global-allocated" to "global" to be in line with FUNC's "global". Signed-off-by: Andrii Nakryiko Acked-by: Yonghong Song --- tools/bpf/bpftool/btf.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/tools/bpf/bpftool/btf.c b/tools/bpf/bpftool/btf.c index 62953bbf68b4..001749a34899 100644 --- a/tools/bpf/bpftool/btf.c +++ b/tools/bpf/bpftool/btf.c @@ -71,7 +71,9 @@ static const char *btf_var_linkage_str(__u32 linkage) case BTF_VAR_STATIC: return "static"; case BTF_VAR_GLOBAL_ALLOCATED: - return "global-alloc"; + return "global"; + case BTF_VAR_GLOBAL_EXTERN: + return "extern"; default: return "(unknown)"; } From patchwork Fri Apr 16 20:23:49 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrii Nakryiko X-Patchwork-Id: 12208707 X-Patchwork-Delegate: bpf@iogearbox.net 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=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 50AF6C433ED for ; Fri, 16 Apr 2021 20:24:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2FFE16124B for ; Fri, 16 Apr 2021 20:24:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245430AbhDPUYh convert rfc822-to-8bit (ORCPT ); Fri, 16 Apr 2021 16:24:37 -0400 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:5972 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245269AbhDPUYh (ORCPT ); Fri, 16 Apr 2021 16:24:37 -0400 Received: from pps.filterd (m0044012.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.43/8.16.0.43) with SMTP id 13GKKDJm021875 for ; Fri, 16 Apr 2021 13:24:12 -0700 Received: from mail.thefacebook.com ([163.114.132.120]) by mx0a-00082601.pphosted.com with ESMTP id 37yb5j2f5v-3 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Fri, 16 Apr 2021 13:24:11 -0700 Received: from intmgw001.05.ash9.facebook.com (2620:10d:c085:208::f) 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; Fri, 16 Apr 2021 13:24:10 -0700 Received: by devbig012.ftw2.facebook.com (Postfix, from userid 137359) id 3F9A52ED4EE0; Fri, 16 Apr 2021 13:24:09 -0700 (PDT) From: Andrii Nakryiko To: , , , CC: , Subject: [PATCH v2 bpf-next 02/17] bpftool: dump more info about DATASEC members Date: Fri, 16 Apr 2021 13:23:49 -0700 Message-ID: <20210416202404.3443623-3-andrii@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210416202404.3443623-1-andrii@kernel.org> References: <20210416202404.3443623-1-andrii@kernel.org> MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-GUID: bImegzXa42RYFHWRjRpQAlmwgejKvqid X-Proofpoint-ORIG-GUID: bImegzXa42RYFHWRjRpQAlmwgejKvqid X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.391,18.0.761 definitions=2021-04-16_09:2021-04-16,2021-04-16 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 clxscore=1034 phishscore=0 priorityscore=1501 mlxlogscore=999 spamscore=0 bulkscore=0 lowpriorityscore=0 impostorscore=0 adultscore=0 suspectscore=0 mlxscore=0 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2104060000 definitions=main-2104160143 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net Dump succinct information for each member of DATASEC: its kinds and name. This is extremely helpful to see at a quick glance what is inside each DATASEC of a given BTF. Without this, one has to jump around BTF data to just find out the name of a VAR or FUNC. DATASEC's var_secinfo member is special in that regard because it doesn't itself contain the name of the member, delegating that to the referenced VAR and FUNC kinds. Other kinds, like STRUCT/UNION/FUNC/ENUM, encode member names directly and thus are clearly identifiable in BTF dump. The new output looks like this: [35] DATASEC '.bss' size=0 vlen=6 type_id=8 offset=0 size=4 (VAR 'input_bss1') type_id=13 offset=0 size=4 (VAR 'input_bss_weak') type_id=16 offset=0 size=4 (VAR 'output_bss1') type_id=17 offset=0 size=4 (VAR 'output_data1') type_id=18 offset=0 size=4 (VAR 'output_rodata1') type_id=20 offset=0 size=8 (VAR 'output_sink1') [36] DATASEC '.data' size=0 vlen=2 type_id=9 offset=0 size=4 (VAR 'input_data1') type_id=14 offset=0 size=4 (VAR 'input_data_weak') [37] DATASEC '.kconfig' size=0 vlen=2 type_id=25 offset=0 size=4 (VAR 'LINUX_KERNEL_VERSION') type_id=28 offset=0 size=1 (VAR 'CONFIG_BPF_SYSCALL') [38] DATASEC '.ksyms' size=0 vlen=1 type_id=30 offset=0 size=1 (VAR 'bpf_link_fops') [39] DATASEC '.rodata' size=0 vlen=2 type_id=12 offset=0 size=4 (VAR 'input_rodata1') type_id=15 offset=0 size=4 (VAR 'input_rodata_weak') [40] DATASEC 'license' size=0 vlen=1 type_id=24 offset=0 size=4 (VAR 'LICENSE') Signed-off-by: Andrii Nakryiko Acked-by: Yonghong Song --- tools/bpf/bpftool/btf.c | 26 ++++++++++++++++++-------- 1 file changed, 18 insertions(+), 8 deletions(-) diff --git a/tools/bpf/bpftool/btf.c b/tools/bpf/bpftool/btf.c index 001749a34899..385d5c955cf3 100644 --- a/tools/bpf/bpftool/btf.c +++ b/tools/bpf/bpftool/btf.c @@ -100,26 +100,28 @@ static const char *btf_str(const struct btf *btf, __u32 off) return btf__name_by_offset(btf, off) ? : "(invalid)"; } +static int btf_kind_safe(int kind) +{ + return kind <= BTF_KIND_MAX ? kind : BTF_KIND_UNKN; +} + static int dump_btf_type(const struct btf *btf, __u32 id, const struct btf_type *t) { json_writer_t *w = json_wtr; - int kind, safe_kind; - - kind = BTF_INFO_KIND(t->info); - safe_kind = kind <= BTF_KIND_MAX ? kind : BTF_KIND_UNKN; + int kind = btf_kind(t); if (json_output) { jsonw_start_object(w); jsonw_uint_field(w, "id", id); - jsonw_string_field(w, "kind", btf_kind_str[safe_kind]); + jsonw_string_field(w, "kind", btf_kind_str[btf_kind_safe(kind)]); jsonw_string_field(w, "name", btf_str(btf, t->name_off)); } else { - printf("[%u] %s '%s'", id, btf_kind_str[safe_kind], + printf("[%u] %s '%s'", id, btf_kind_str[btf_kind_safe(kind)], btf_str(btf, t->name_off)); } - switch (BTF_INFO_KIND(t->info)) { + switch (kind) { case BTF_KIND_INT: { __u32 v = *(__u32 *)(t + 1); const char *enc; @@ -302,7 +304,8 @@ static int dump_btf_type(const struct btf *btf, __u32 id, break; } case BTF_KIND_DATASEC: { - const struct btf_var_secinfo *v = (const void *)(t+1); + const struct btf_var_secinfo *v = (const void *)(t + 1); + const struct btf_type *vt; __u16 vlen = BTF_INFO_VLEN(t->info); int i; @@ -324,6 +327,13 @@ static int dump_btf_type(const struct btf *btf, __u32 id, } else { printf("\n\ttype_id=%u offset=%u size=%u", v->type, v->offset, v->size); + + if (v->type <= btf__get_nr_types(btf)) { + vt = btf__type_by_id(btf, v->type); + printf(" (%s '%s')", + btf_kind_str[btf_kind_safe(btf_kind(vt))], + btf_str(btf, vt->name_off)); + } } } if (json_output) From patchwork Fri Apr 16 20:23:50 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrii Nakryiko X-Patchwork-Id: 12208709 X-Patchwork-Delegate: bpf@iogearbox.net 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=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 43647C43462 for ; Fri, 16 Apr 2021 20:24:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1A0DC6124B for ; Fri, 16 Apr 2021 20:24:14 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244549AbhDPUYi convert rfc822-to-8bit (ORCPT ); Fri, 16 Apr 2021 16:24:38 -0400 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:11004 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245498AbhDPUYh (ORCPT ); Fri, 16 Apr 2021 16:24:37 -0400 Received: from pps.filterd (m0044012.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.43/8.16.0.43) with SMTP id 13GKKI53022045 for ; Fri, 16 Apr 2021 13:24:12 -0700 Received: from mail.thefacebook.com ([163.114.132.120]) by mx0a-00082601.pphosted.com with ESMTP id 37yb5j2f62-2 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Fri, 16 Apr 2021 13:24:12 -0700 Received: from intmgw001.25.frc3.facebook.com (2620:10d:c085:208::f) by mail.thefacebook.com (2620:10d:c085:21d::5) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Fri, 16 Apr 2021 13:24:12 -0700 Received: by devbig012.ftw2.facebook.com (Postfix, from userid 137359) id 4B53C2ED4EE0; Fri, 16 Apr 2021 13:24:11 -0700 (PDT) From: Andrii Nakryiko To: , , , CC: , Subject: [PATCH v2 bpf-next 03/17] libbpf: suppress compiler warning when using SEC() macro with externs Date: Fri, 16 Apr 2021 13:23:50 -0700 Message-ID: <20210416202404.3443623-4-andrii@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210416202404.3443623-1-andrii@kernel.org> References: <20210416202404.3443623-1-andrii@kernel.org> MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-GUID: lnFcmY9Ysjn0MdSmH6hwRUAVpWrwzHDR X-Proofpoint-ORIG-GUID: lnFcmY9Ysjn0MdSmH6hwRUAVpWrwzHDR X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.391,18.0.761 definitions=2021-04-16_09:2021-04-16,2021-04-16 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 clxscore=1015 phishscore=0 priorityscore=1501 mlxlogscore=999 spamscore=0 bulkscore=0 lowpriorityscore=0 impostorscore=0 adultscore=0 suspectscore=0 mlxscore=0 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2104060000 definitions=main-2104160143 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net When used on externs SEC() macro will trigger compilation warning about inapplicable `__attribute__((used))`. That's expected for extern declarations, so suppress it with the corresponding _Pragma. Signed-off-by: Andrii Nakryiko Acked-by: Yonghong Song --- tools/lib/bpf/bpf_helpers.h | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-) diff --git a/tools/lib/bpf/bpf_helpers.h b/tools/lib/bpf/bpf_helpers.h index b904128626c2..75c7581b304c 100644 --- a/tools/lib/bpf/bpf_helpers.h +++ b/tools/lib/bpf/bpf_helpers.h @@ -25,9 +25,16 @@ /* * Helper macro to place programs, maps, license in * different sections in elf_bpf file. Section names - * are interpreted by elf_bpf loader + * are interpreted by libbpf depending on the context (BPF programs, BPF maps, + * extern variables, etc). + * To allow use of SEC() with externs (e.g., for extern .maps declarations), + * make sure __attribute__((unused)) doesn't trigger compilation warning. */ -#define SEC(NAME) __attribute__((section(NAME), used)) +#define SEC(name) \ + _Pragma("GCC diagnostic push") \ + _Pragma("GCC diagnostic ignored \"-Wignored-attributes\"") \ + __attribute__((section(name), used)) \ + _Pragma("GCC diagnostic pop") \ /* Avoid 'linux/stddef.h' definition of '__always_inline'. */ #undef __always_inline From patchwork Fri Apr 16 20:23:51 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrii Nakryiko X-Patchwork-Id: 12208713 X-Patchwork-Delegate: bpf@iogearbox.net 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=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 15E74C433B4 for ; Fri, 16 Apr 2021 20:24:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E291F613CD for ; Fri, 16 Apr 2021 20:24:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245567AbhDPUYl convert rfc822-to-8bit (ORCPT ); Fri, 16 Apr 2021 16:24:41 -0400 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:26620 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245518AbhDPUYj (ORCPT ); Fri, 16 Apr 2021 16:24:39 -0400 Received: from pps.filterd (m0109334.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.43/8.16.0.43) with SMTP id 13GKI1VC001256 for ; Fri, 16 Apr 2021 13:24:14 -0700 Received: from mail.thefacebook.com ([163.114.132.120]) by mx0a-00082601.pphosted.com with ESMTP id 37ydj4sjcw-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Fri, 16 Apr 2021 13:24:14 -0700 Received: from intmgw002.25.frc3.facebook.com (2620:10d:c085:208::f) by mail.thefacebook.com (2620:10d:c085:21d::4) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Fri, 16 Apr 2021 13:24:14 -0700 Received: by devbig012.ftw2.facebook.com (Postfix, from userid 137359) id 561942ED4EE0; Fri, 16 Apr 2021 13:24:13 -0700 (PDT) From: Andrii Nakryiko To: , , , CC: , Subject: [PATCH v2 bpf-next 04/17] libbpf: mark BPF subprogs with hidden visibility as static for BPF verifier Date: Fri, 16 Apr 2021 13:23:51 -0700 Message-ID: <20210416202404.3443623-5-andrii@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210416202404.3443623-1-andrii@kernel.org> References: <20210416202404.3443623-1-andrii@kernel.org> MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-GUID: EvHCU6dhlZcckROlkybpBvvbG6rbtxi5 X-Proofpoint-ORIG-GUID: EvHCU6dhlZcckROlkybpBvvbG6rbtxi5 X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.391,18.0.761 definitions=2021-04-16_09:2021-04-16,2021-04-16 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 clxscore=1015 suspectscore=0 phishscore=0 lowpriorityscore=0 impostorscore=0 bulkscore=0 spamscore=0 priorityscore=1501 malwarescore=0 mlxscore=0 adultscore=0 mlxlogscore=999 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2104060000 definitions=main-2104160143 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net Define __hidden helper macro in bpf_helpers.h, which is a short-hand for __attribute__((visibility("hidden"))). Add libbpf support to mark BPF subprograms marked with __hidden as static in BTF information to enforce BPF verifier's static function validation algorithm, which takes more information (caller's context) into account during a subprogram validation. Signed-off-by: Andrii Nakryiko --- tools/lib/bpf/bpf_helpers.h | 8 ++++++ tools/lib/bpf/btf.c | 5 ---- tools/lib/bpf/libbpf.c | 45 ++++++++++++++++++++++++++++++++- tools/lib/bpf/libbpf_internal.h | 6 +++++ 4 files changed, 58 insertions(+), 6 deletions(-) diff --git a/tools/lib/bpf/bpf_helpers.h b/tools/lib/bpf/bpf_helpers.h index 75c7581b304c..9720dc0b4605 100644 --- a/tools/lib/bpf/bpf_helpers.h +++ b/tools/lib/bpf/bpf_helpers.h @@ -47,6 +47,14 @@ #define __weak __attribute__((weak)) #endif +/* + * Use __hidden attribute to mark a non-static BPF subprogram effectively + * static for BPF verifier's verification algorithm purposes, allowing more + * extensive and permissive BPF verification process, taking into account + * subprogram's caller context. + */ +#define __hidden __attribute__((visibility("hidden"))) + /* When utilizing vmlinux.h with BPF CO-RE, user BPF programs can't include * any system-level headers (such as stddef.h, linux/version.h, etc), and * commonly-used macros like NULL and KERNEL_VERSION aren't available through diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index d30e67e7e1e5..d57e13a13798 100644 --- a/tools/lib/bpf/btf.c +++ b/tools/lib/bpf/btf.c @@ -1605,11 +1605,6 @@ static void *btf_add_type_mem(struct btf *btf, size_t add_sz) btf->hdr->type_len, UINT_MAX, add_sz); } -static __u32 btf_type_info(int kind, int vlen, int kflag) -{ - return (kflag << 31) | (kind << 24) | vlen; -} - static void btf_type_inc_vlen(struct btf_type *t) { t->info = btf_type_info(btf_kind(t), btf_vlen(t) + 1, btf_kflag(t)); diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index 9cc2d45b0080..ce5558d0a61b 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -71,6 +71,7 @@ static struct bpf_map *bpf_object__add_map(struct bpf_object *obj); static const struct btf_type * skip_mods_and_typedefs(const struct btf *btf, __u32 id, __u32 *res_id); +static bool prog_is_subprog(const struct bpf_object *obj, const struct bpf_program *prog); static int __base_pr(enum libbpf_print_level level, const char *format, va_list args) @@ -274,6 +275,7 @@ struct bpf_program { bpf_program_clear_priv_t clear_priv; bool load; + bool mark_btf_static; enum bpf_prog_type type; enum bpf_attach_type expected_attach_type; int prog_ifindex; @@ -698,6 +700,15 @@ bpf_object__add_programs(struct bpf_object *obj, Elf_Data *sec_data, if (err) return err; + /* if function is a global/weak symbol, but has hidden + * visibility (or any non-default one), mark its BTF FUNC as + * static to enable more permissive BPF verification mode with + * more outside context available to BPF verifier + */ + if (GELF_ST_BIND(sym.st_info) != STB_LOCAL + && GELF_ST_VISIBILITY(sym.st_other) != STV_DEFAULT) + prog->mark_btf_static = true; + nr_progs++; obj->nr_programs = nr_progs; @@ -2618,7 +2629,7 @@ static int bpf_object__sanitize_and_load_btf(struct bpf_object *obj) { struct btf *kern_btf = obj->btf; bool btf_mandatory, sanitize; - int err = 0; + int i, err = 0; if (!obj->btf) return 0; @@ -2632,6 +2643,38 @@ static int bpf_object__sanitize_and_load_btf(struct bpf_object *obj) return 0; } + /* Even though some subprogs are global/weak, user might prefer more + * permissive BPF verification process that BPF verifier performs for + * static functions, taking into account more context from the caller + * functions. In such case, they need to mark such subprogs with + * __attribute__((visibility("hidden"))) and libbpf will adjust + * corresponding FUNC BTF type to be marked as static and trigger more + * involved BPF verification process. + */ + for (i = 0; i < obj->nr_programs; i++) { + struct bpf_program *prog = &obj->programs[i]; + struct btf_type *t; + const char *name; + int j, n; + + if (!prog->mark_btf_static || !prog_is_subprog(obj, prog)) + continue; + + n = btf__get_nr_types(obj->btf); + for (j = 1; j <= n; j++) { + t = btf_type_by_id(obj->btf, j); + if (!btf_is_func(t) || btf_func_linkage(t) != BTF_FUNC_GLOBAL) + continue; + + name = btf__str_by_offset(obj->btf, t->name_off); + if (strcmp(name, prog->name) != 0) + continue; + + t->info = btf_type_info(BTF_KIND_FUNC, BTF_FUNC_STATIC, 0); + break; + } + } + sanitize = btf_needs_sanitization(obj); if (sanitize) { const void *raw_data; diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h index 6017902c687e..92b7eae10c6d 100644 --- a/tools/lib/bpf/libbpf_internal.h +++ b/tools/lib/bpf/libbpf_internal.h @@ -19,6 +19,7 @@ #pragma GCC poison reallocarray #include "libbpf.h" +#include "btf.h" #ifndef EM_BPF #define EM_BPF 247 @@ -132,6 +133,11 @@ struct btf_type; struct btf_type *btf_type_by_id(struct btf *btf, __u32 type_id); +static inline __u32 btf_type_info(int kind, int vlen, int kflag) +{ + return (kflag << 31) | (kind << 24) | vlen; +} + void *libbpf_add_mem(void **data, size_t *cap_cnt, size_t elem_sz, size_t cur_cnt, size_t max_cnt, size_t add_cnt); int libbpf_ensure_mem(void **data, size_t *cap_cnt, size_t elem_sz, size_t need_cnt); From patchwork Fri Apr 16 20:23:52 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrii Nakryiko X-Patchwork-Id: 12208715 X-Patchwork-Delegate: bpf@iogearbox.net 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=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 49BABC433B4 for ; Fri, 16 Apr 2021 20:24:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 25692613CF for ; Fri, 16 Apr 2021 20:24:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245600AbhDPUYr convert rfc822-to-8bit (ORCPT ); Fri, 16 Apr 2021 16:24:47 -0400 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:34462 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245636AbhDPUYq (ORCPT ); Fri, 16 Apr 2021 16:24:46 -0400 Received: from pps.filterd (m0044010.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.43/8.16.0.43) with SMTP id 13GKLVTi021272 for ; Fri, 16 Apr 2021 13:24:21 -0700 Received: from mail.thefacebook.com ([163.114.132.120]) by mx0a-00082601.pphosted.com with ESMTP id 37yb9y2dpr-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Fri, 16 Apr 2021 13:24:21 -0700 Received: from intmgw001.38.frc1.facebook.com (2620:10d:c085:108::4) by mail.thefacebook.com (2620:10d:c085:21d::5) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Fri, 16 Apr 2021 13:24:20 -0700 Received: by devbig012.ftw2.facebook.com (Postfix, from userid 137359) id 614C72ED4EE0; Fri, 16 Apr 2021 13:24:15 -0700 (PDT) From: Andrii Nakryiko To: , , , CC: , Subject: [PATCH v2 bpf-next 05/17] libbpf: allow gaps in BPF program sections to support overriden weak functions Date: Fri, 16 Apr 2021 13:23:52 -0700 Message-ID: <20210416202404.3443623-6-andrii@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210416202404.3443623-1-andrii@kernel.org> References: <20210416202404.3443623-1-andrii@kernel.org> MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-ORIG-GUID: IEbVvZ21w8mc4-9lQW0moKBWeCZuy-DS X-Proofpoint-GUID: IEbVvZ21w8mc4-9lQW0moKBWeCZuy-DS X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.391,18.0.761 definitions=2021-04-16_09:2021-04-16,2021-04-16 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 malwarescore=0 spamscore=0 priorityscore=1501 phishscore=0 adultscore=0 lowpriorityscore=0 bulkscore=0 mlxscore=0 suspectscore=0 impostorscore=0 mlxlogscore=999 clxscore=1015 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2104060000 definitions=main-2104160143 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net Currently libbpf is very strict about parsing BPF program isnstruction sections. No gaps are allowed between sequential BPF programs within a given ELF section. Libbpf enforced that by keeping track of the next section offset that should start a new BPF (sub)program and cross-checks that by searching for a corresponding STT_FUNC ELF symbol. But this is too restrictive once we allow to have weak BPF programs and link together two or more BPF object files. In such case, some weak BPF programs might be "overriden" by either non-weak BPF program with the same name and signature, or even by another weak BPF program that just happened to be linked first. That, in turn, leaves BPF instructions of the "lost" BPF (sub)program intact, but there is no corresponding ELF symbol, because no one is going to be referencing it. Libbpf already correctly handles such cases in the sense that it won't append such dead code to actual BPF programs loaded into kernel. So the only change that needs to be done is to relax the logic of parsing BPF instruction sections. Instead of assuming next BPF (sub)program section offset, iterate available STT_FUNC ELF symbols to discover all available BPF subprograms and programs. Signed-off-by: Andrii Nakryiko Acked-by: Yonghong Song --- tools/lib/bpf/libbpf.c | 56 ++++++++++++++++-------------------------- 1 file changed, 21 insertions(+), 35 deletions(-) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index ce5558d0a61b..a0e6d6bc47f3 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -502,8 +502,6 @@ static Elf_Scn *elf_sec_by_name(const struct bpf_object *obj, const char *name); static int elf_sec_hdr(const struct bpf_object *obj, Elf_Scn *scn, GElf_Shdr *hdr); static const char *elf_sec_name(const struct bpf_object *obj, Elf_Scn *scn); static Elf_Data *elf_sec_data(const struct bpf_object *obj, Elf_Scn *scn); -static int elf_sym_by_sec_off(const struct bpf_object *obj, size_t sec_idx, - size_t off, __u32 sym_type, GElf_Sym *sym); void bpf_program__unload(struct bpf_program *prog) { @@ -644,10 +642,12 @@ static int bpf_object__add_programs(struct bpf_object *obj, Elf_Data *sec_data, const char *sec_name, int sec_idx) { + Elf_Data *symbols = obj->efile.symbols; struct bpf_program *prog, *progs; void *data = sec_data->d_buf; size_t sec_sz = sec_data->d_size, sec_off, prog_sz; - int nr_progs, err; + size_t n = symbols->d_size / sizeof(GElf_Sym); + int nr_progs, err, i; const char *name; GElf_Sym sym; @@ -655,14 +655,16 @@ bpf_object__add_programs(struct bpf_object *obj, Elf_Data *sec_data, nr_progs = obj->nr_programs; sec_off = 0; - while (sec_off < sec_sz) { - if (elf_sym_by_sec_off(obj, sec_idx, sec_off, STT_FUNC, &sym)) { - pr_warn("sec '%s': failed to find program symbol at offset %zu\n", - sec_name, sec_off); - return -LIBBPF_ERRNO__FORMAT; - } + for (i = 0; i < n; i++) { + if (!gelf_getsym(symbols, i, &sym)) + continue; + if (sym.st_shndx != sec_idx) + continue; + if (GELF_ST_TYPE(sym.st_info) != STT_FUNC) + continue; prog_sz = sym.st_size; + sec_off = sym.st_value; name = elf_sym_str(obj, sym.st_name); if (!name) { @@ -711,8 +713,6 @@ bpf_object__add_programs(struct bpf_object *obj, Elf_Data *sec_data, nr_progs++; obj->nr_programs = nr_progs; - - sec_off += prog_sz; } return 0; @@ -2825,26 +2825,6 @@ static Elf_Data *elf_sec_data(const struct bpf_object *obj, Elf_Scn *scn) return data; } -static int elf_sym_by_sec_off(const struct bpf_object *obj, size_t sec_idx, - size_t off, __u32 sym_type, GElf_Sym *sym) -{ - Elf_Data *symbols = obj->efile.symbols; - size_t n = symbols->d_size / sizeof(GElf_Sym); - int i; - - for (i = 0; i < n; i++) { - if (!gelf_getsym(symbols, i, sym)) - continue; - if (sym->st_shndx != sec_idx || sym->st_value != off) - continue; - if (GELF_ST_TYPE(sym->st_info) != sym_type) - continue; - return 0; - } - - return -ENOENT; -} - static bool is_sec_name_dwarf(const char *name) { /* approximation, but the actual list is too long */ @@ -3723,11 +3703,16 @@ bpf_object__collect_prog_relos(struct bpf_object *obj, GElf_Shdr *shdr, Elf_Data int err, i, nrels; const char *sym_name; __u32 insn_idx; + Elf_Scn *scn; + Elf_Data *scn_data; GElf_Sym sym; GElf_Rel rel; + scn = elf_sec_by_idx(obj, sec_idx); + scn_data = elf_sec_data(obj, scn); + relo_sec_name = elf_sec_str(obj, shdr->sh_name); - sec_name = elf_sec_name(obj, elf_sec_by_idx(obj, sec_idx)); + sec_name = elf_sec_name(obj, scn); if (!relo_sec_name || !sec_name) return -EINVAL; @@ -3745,7 +3730,8 @@ bpf_object__collect_prog_relos(struct bpf_object *obj, GElf_Shdr *shdr, Elf_Data relo_sec_name, (size_t)GELF_R_SYM(rel.r_info), i); return -LIBBPF_ERRNO__FORMAT; } - if (rel.r_offset % BPF_INSN_SZ) { + + if (rel.r_offset % BPF_INSN_SZ || rel.r_offset >= scn_data->d_size) { pr_warn("sec '%s': invalid offset 0x%zx for relo #%d\n", relo_sec_name, (size_t)GELF_R_SYM(rel.r_info), i); return -LIBBPF_ERRNO__FORMAT; @@ -3769,9 +3755,9 @@ bpf_object__collect_prog_relos(struct bpf_object *obj, GElf_Shdr *shdr, Elf_Data prog = find_prog_by_sec_insn(obj, sec_idx, insn_idx); if (!prog) { - pr_warn("sec '%s': relo #%d: program not found in section '%s' for insn #%u\n", + pr_debug("sec '%s': relo #%d: couldn't find program in section '%s' for insn #%u, probably overridden weak function, skipping...\n", relo_sec_name, i, sec_name, insn_idx); - return -LIBBPF_ERRNO__RELOC; + continue; } relos = libbpf_reallocarray(prog->reloc_desc, From patchwork Fri Apr 16 20:23:53 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrii Nakryiko X-Patchwork-Id: 12208717 X-Patchwork-Delegate: bpf@iogearbox.net 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 31BCAC433B4 for ; Fri, 16 Apr 2021 20:24:27 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0E42161166 for ; Fri, 16 Apr 2021 20:24:27 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245624AbhDPUYv convert rfc822-to-8bit (ORCPT ); Fri, 16 Apr 2021 16:24:51 -0400 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:43970 "EHLO mx0b-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245537AbhDPUYs (ORCPT ); Fri, 16 Apr 2021 16:24:48 -0400 Received: from pps.filterd (m0148460.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.43/8.16.0.43) with SMTP id 13GKIujl026839 for ; Fri, 16 Apr 2021 13:24:23 -0700 Received: from maileast.thefacebook.com ([163.114.130.16]) by mx0a-00082601.pphosted.com with ESMTP id 37yb5e2dh0-19 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Fri, 16 Apr 2021 13:24:22 -0700 Received: from intmgw002.06.ash9.facebook.com (2620:10d:c0a8:1b::d) by mail.thefacebook.com (2620:10d:c0a8:83::4) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Fri, 16 Apr 2021 13:24:21 -0700 Received: by devbig012.ftw2.facebook.com (Postfix, from userid 137359) id 6BC2A2ED4EE0; Fri, 16 Apr 2021 13:24:17 -0700 (PDT) From: Andrii Nakryiko To: , , , CC: , Subject: [PATCH v2 bpf-next 06/17] libbpf: refactor BTF map definition parsing Date: Fri, 16 Apr 2021 13:23:53 -0700 Message-ID: <20210416202404.3443623-7-andrii@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210416202404.3443623-1-andrii@kernel.org> References: <20210416202404.3443623-1-andrii@kernel.org> MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-GUID: Bfsrctn0N3L4Vfug9PHK0Qa7oTOwzmKa X-Proofpoint-ORIG-GUID: Bfsrctn0N3L4Vfug9PHK0Qa7oTOwzmKa X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.391,18.0.761 definitions=2021-04-16_09:2021-04-16,2021-04-16 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 bulkscore=0 adultscore=0 mlxlogscore=999 spamscore=0 clxscore=1015 malwarescore=0 priorityscore=1501 lowpriorityscore=0 impostorscore=0 phishscore=0 suspectscore=0 mlxscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2104060000 definitions=main-2104160143 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net Refactor BTF-defined maps parsing logic to allow it to be nicely reused by BPF static linker. Further, at least for BPF static linker, it's important to know which attributes of a BPF map were defined explicitly, so provide a bit set for each known portion of BTF map definition. This allows BPF static linker to do a simple check when dealing with extern map declarations. The same capabilities allow to distinguish attributes explicitly set to zero (e.g., __uint(max_entries, 0)) vs the case of not specifying it at all (no max_entries attribute at all). Libbpf is currently not utilizing that, but it could be useful for backwards compatibility reasons later. Signed-off-by: Andrii Nakryiko --- tools/lib/bpf/libbpf.c | 256 ++++++++++++++++++-------------- tools/lib/bpf/libbpf_internal.h | 32 ++++ 2 files changed, 177 insertions(+), 111 deletions(-) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index a0e6d6bc47f3..f6f4126389ac 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -2025,255 +2025,262 @@ static int build_map_pin_path(struct bpf_map *map, const char *path) return bpf_map__set_pin_path(map, buf); } - -static int parse_btf_map_def(struct bpf_object *obj, - struct bpf_map *map, - const struct btf_type *def, - bool strict, bool is_inner, - const char *pin_root_path) +int parse_btf_map_def(const char *map_name, struct btf *btf, + const struct btf_type *def_t, bool strict, + struct btf_map_def *map_def, struct btf_map_def *inner_def) { const struct btf_type *t; const struct btf_member *m; + bool is_inner = inner_def == NULL; int vlen, i; - vlen = btf_vlen(def); - m = btf_members(def); + vlen = btf_vlen(def_t); + m = btf_members(def_t); for (i = 0; i < vlen; i++, m++) { - const char *name = btf__name_by_offset(obj->btf, m->name_off); + const char *name = btf__name_by_offset(btf, m->name_off); if (!name) { - pr_warn("map '%s': invalid field #%d.\n", map->name, i); + pr_warn("map '%s': invalid field #%d.\n", map_name, i); return -EINVAL; } if (strcmp(name, "type") == 0) { - if (!get_map_field_int(map->name, obj->btf, m, - &map->def.type)) + if (!get_map_field_int(map_name, btf, m, &map_def->map_type)) return -EINVAL; - pr_debug("map '%s': found type = %u.\n", - map->name, map->def.type); + map_def->parts |= MAP_DEF_MAP_TYPE; } else if (strcmp(name, "max_entries") == 0) { - if (!get_map_field_int(map->name, obj->btf, m, - &map->def.max_entries)) + if (!get_map_field_int(map_name, btf, m, &map_def->max_entries)) return -EINVAL; - pr_debug("map '%s': found max_entries = %u.\n", - map->name, map->def.max_entries); + map_def->parts |= MAP_DEF_MAX_ENTRIES; } else if (strcmp(name, "map_flags") == 0) { - if (!get_map_field_int(map->name, obj->btf, m, - &map->def.map_flags)) + if (!get_map_field_int(map_name, btf, m, &map_def->map_flags)) return -EINVAL; - pr_debug("map '%s': found map_flags = %u.\n", - map->name, map->def.map_flags); + map_def->parts |= MAP_DEF_MAP_FLAGS; } else if (strcmp(name, "numa_node") == 0) { - if (!get_map_field_int(map->name, obj->btf, m, &map->numa_node)) + if (!get_map_field_int(map_name, btf, m, &map_def->numa_node)) return -EINVAL; - pr_debug("map '%s': found numa_node = %u.\n", map->name, map->numa_node); + map_def->parts |= MAP_DEF_NUMA_NODE; } else if (strcmp(name, "key_size") == 0) { __u32 sz; - if (!get_map_field_int(map->name, obj->btf, m, &sz)) + if (!get_map_field_int(map_name, btf, m, &sz)) return -EINVAL; - pr_debug("map '%s': found key_size = %u.\n", - map->name, sz); - if (map->def.key_size && map->def.key_size != sz) { + if (map_def->key_size && map_def->key_size != sz) { pr_warn("map '%s': conflicting key size %u != %u.\n", - map->name, map->def.key_size, sz); + map_name, map_def->key_size, sz); return -EINVAL; } - map->def.key_size = sz; + map_def->key_size = sz; + map_def->parts |= MAP_DEF_KEY_SIZE; } else if (strcmp(name, "key") == 0) { __s64 sz; - t = btf__type_by_id(obj->btf, m->type); + t = btf__type_by_id(btf, m->type); if (!t) { pr_warn("map '%s': key type [%d] not found.\n", - map->name, m->type); + map_name, m->type); return -EINVAL; } if (!btf_is_ptr(t)) { pr_warn("map '%s': key spec is not PTR: %s.\n", - map->name, btf_kind_str(t)); + map_name, btf_kind_str(t)); return -EINVAL; } - sz = btf__resolve_size(obj->btf, t->type); + sz = btf__resolve_size(btf, t->type); if (sz < 0) { pr_warn("map '%s': can't determine key size for type [%u]: %zd.\n", - map->name, t->type, (ssize_t)sz); + map_name, t->type, (ssize_t)sz); return sz; } - pr_debug("map '%s': found key [%u], sz = %zd.\n", - map->name, t->type, (ssize_t)sz); - if (map->def.key_size && map->def.key_size != sz) { + if (map_def->key_size && map_def->key_size != sz) { pr_warn("map '%s': conflicting key size %u != %zd.\n", - map->name, map->def.key_size, (ssize_t)sz); + map_name, map_def->key_size, (ssize_t)sz); return -EINVAL; } - map->def.key_size = sz; - map->btf_key_type_id = t->type; + map_def->key_size = sz; + map_def->key_type_id = t->type; + map_def->parts |= MAP_DEF_KEY_SIZE | MAP_DEF_KEY_TYPE; } else if (strcmp(name, "value_size") == 0) { __u32 sz; - if (!get_map_field_int(map->name, obj->btf, m, &sz)) + if (!get_map_field_int(map_name, btf, m, &sz)) return -EINVAL; - pr_debug("map '%s': found value_size = %u.\n", - map->name, sz); - if (map->def.value_size && map->def.value_size != sz) { + if (map_def->value_size && map_def->value_size != sz) { pr_warn("map '%s': conflicting value size %u != %u.\n", - map->name, map->def.value_size, sz); + map_name, map_def->value_size, sz); return -EINVAL; } - map->def.value_size = sz; + map_def->value_size = sz; + map_def->parts |= MAP_DEF_VALUE_SIZE; } else if (strcmp(name, "value") == 0) { __s64 sz; - t = btf__type_by_id(obj->btf, m->type); + t = btf__type_by_id(btf, m->type); if (!t) { pr_warn("map '%s': value type [%d] not found.\n", - map->name, m->type); + map_name, m->type); return -EINVAL; } if (!btf_is_ptr(t)) { pr_warn("map '%s': value spec is not PTR: %s.\n", - map->name, btf_kind_str(t)); + map_name, btf_kind_str(t)); return -EINVAL; } - sz = btf__resolve_size(obj->btf, t->type); + sz = btf__resolve_size(btf, t->type); if (sz < 0) { pr_warn("map '%s': can't determine value size for type [%u]: %zd.\n", - map->name, t->type, (ssize_t)sz); + map_name, t->type, (ssize_t)sz); return sz; } - pr_debug("map '%s': found value [%u], sz = %zd.\n", - map->name, t->type, (ssize_t)sz); - if (map->def.value_size && map->def.value_size != sz) { + if (map_def->value_size && map_def->value_size != sz) { pr_warn("map '%s': conflicting value size %u != %zd.\n", - map->name, map->def.value_size, (ssize_t)sz); + map_name, map_def->value_size, (ssize_t)sz); return -EINVAL; } - map->def.value_size = sz; - map->btf_value_type_id = t->type; + map_def->value_size = sz; + map_def->value_type_id = t->type; + map_def->parts |= MAP_DEF_VALUE_SIZE | MAP_DEF_VALUE_TYPE; } else if (strcmp(name, "values") == 0) { + char inner_map_name[128]; int err; if (is_inner) { pr_warn("map '%s': multi-level inner maps not supported.\n", - map->name); + map_name); return -ENOTSUP; } if (i != vlen - 1) { pr_warn("map '%s': '%s' member should be last.\n", - map->name, name); + map_name, name); return -EINVAL; } - if (!bpf_map_type__is_map_in_map(map->def.type)) { + if (!bpf_map_type__is_map_in_map(map_def->map_type)) { pr_warn("map '%s': should be map-in-map.\n", - map->name); + map_name); return -ENOTSUP; } - if (map->def.value_size && map->def.value_size != 4) { + if (map_def->value_size && map_def->value_size != 4) { pr_warn("map '%s': conflicting value size %u != 4.\n", - map->name, map->def.value_size); + map_name, map_def->value_size); return -EINVAL; } - map->def.value_size = 4; - t = btf__type_by_id(obj->btf, m->type); + map_def->value_size = 4; + t = btf__type_by_id(btf, m->type); if (!t) { pr_warn("map '%s': map-in-map inner type [%d] not found.\n", - map->name, m->type); + map_name, m->type); return -EINVAL; } if (!btf_is_array(t) || btf_array(t)->nelems) { pr_warn("map '%s': map-in-map inner spec is not a zero-sized array.\n", - map->name); + map_name); return -EINVAL; } - t = skip_mods_and_typedefs(obj->btf, btf_array(t)->type, - NULL); + t = skip_mods_and_typedefs(btf, btf_array(t)->type, NULL); if (!btf_is_ptr(t)) { pr_warn("map '%s': map-in-map inner def is of unexpected kind %s.\n", - map->name, btf_kind_str(t)); + map_name, btf_kind_str(t)); return -EINVAL; } - t = skip_mods_and_typedefs(obj->btf, t->type, NULL); + t = skip_mods_and_typedefs(btf, t->type, NULL); if (!btf_is_struct(t)) { pr_warn("map '%s': map-in-map inner def is of unexpected kind %s.\n", - map->name, btf_kind_str(t)); + map_name, btf_kind_str(t)); return -EINVAL; } - map->inner_map = calloc(1, sizeof(*map->inner_map)); - if (!map->inner_map) - return -ENOMEM; - map->inner_map->fd = -1; - map->inner_map->sec_idx = obj->efile.btf_maps_shndx; - map->inner_map->name = malloc(strlen(map->name) + - sizeof(".inner") + 1); - if (!map->inner_map->name) - return -ENOMEM; - sprintf(map->inner_map->name, "%s.inner", map->name); - - err = parse_btf_map_def(obj, map->inner_map, t, strict, - true /* is_inner */, NULL); + snprintf(inner_map_name, sizeof(inner_map_name), "%s.inner", map_name); + err = parse_btf_map_def(inner_map_name, btf, t, strict, inner_def, NULL); if (err) return err; + + map_def->parts |= MAP_DEF_INNER_MAP; } else if (strcmp(name, "pinning") == 0) { __u32 val; - int err; if (is_inner) { - pr_debug("map '%s': inner def can't be pinned.\n", - map->name); + pr_warn("map '%s': inner def can't be pinned.\n", map_name); return -EINVAL; } - if (!get_map_field_int(map->name, obj->btf, m, &val)) + if (!get_map_field_int(map_name, btf, m, &val)) return -EINVAL; - pr_debug("map '%s': found pinning = %u.\n", - map->name, val); - - if (val != LIBBPF_PIN_NONE && - val != LIBBPF_PIN_BY_NAME) { + if (val != LIBBPF_PIN_NONE && val != LIBBPF_PIN_BY_NAME) { pr_warn("map '%s': invalid pinning value %u.\n", - map->name, val); + map_name, val); return -EINVAL; } - if (val == LIBBPF_PIN_BY_NAME) { - err = build_map_pin_path(map, pin_root_path); - if (err) { - pr_warn("map '%s': couldn't build pin path.\n", - map->name); - return err; - } - } + map_def->pinning = val; + map_def->parts |= MAP_DEF_PINNING; } else { if (strict) { - pr_warn("map '%s': unknown field '%s'.\n", - map->name, name); + pr_warn("map '%s': unknown field '%s'.\n", map_name, name); return -ENOTSUP; } - pr_debug("map '%s': ignoring unknown field '%s'.\n", - map->name, name); + pr_debug("map '%s': ignoring unknown field '%s'.\n", map_name, name); } } - if (map->def.type == BPF_MAP_TYPE_UNSPEC) { - pr_warn("map '%s': map type isn't specified.\n", map->name); + if (map_def->map_type == BPF_MAP_TYPE_UNSPEC) { + pr_warn("map '%s': map type isn't specified.\n", map_name); return -EINVAL; } return 0; } +static void fill_map_from_def(struct bpf_map *map, const struct btf_map_def *def) +{ + map->def.type = def->map_type; + map->def.key_size = def->key_size; + map->def.value_size = def->value_size; + map->def.max_entries = def->max_entries; + map->def.map_flags = def->map_flags; + + map->numa_node = def->numa_node; + map->btf_key_type_id = def->key_type_id; + map->btf_value_type_id = def->value_type_id; + + if (def->parts & MAP_DEF_MAP_TYPE) + pr_debug("map '%s': found type = %u.\n", map->name, def->map_type); + + if (def->parts & MAP_DEF_KEY_TYPE) + pr_debug("map '%s': found key [%u], sz = %u.\n", + map->name, def->key_type_id, def->key_size); + else if (def->parts & MAP_DEF_KEY_SIZE) + pr_debug("map '%s': found key_size = %u.\n", map->name, def->key_size); + + if (def->parts & MAP_DEF_VALUE_TYPE) + pr_debug("map '%s': found value [%u], sz = %u.\n", + map->name, def->value_type_id, def->value_size); + else if (def->parts & MAP_DEF_VALUE_SIZE) + pr_debug("map '%s': found value_size = %u.\n", map->name, def->value_size); + + if (def->parts & MAP_DEF_MAX_ENTRIES) + pr_debug("map '%s': found max_entries = %u.\n", map->name, def->max_entries); + if (def->parts & MAP_DEF_MAP_FLAGS) + pr_debug("map '%s': found map_flags = %u.\n", map->name, def->map_flags); + if (def->parts & MAP_DEF_PINNING) + pr_debug("map '%s': found pinning = %u.\n", map->name, def->pinning); + if (def->parts & MAP_DEF_NUMA_NODE) + pr_debug("map '%s': found numa_node = %u.\n", map->name, def->numa_node); + + if (def->parts & MAP_DEF_INNER_MAP) + pr_debug("map '%s': found inner map definition.\n", map->name); +} + static int bpf_object__init_user_btf_map(struct bpf_object *obj, const struct btf_type *sec, int var_idx, int sec_idx, const Elf_Data *data, bool strict, const char *pin_root_path) { + struct btf_map_def map_def = {}, inner_def = {}; const struct btf_type *var, *def; const struct btf_var_secinfo *vi; const struct btf_var *var_extra; const char *map_name; struct bpf_map *map; + int err; vi = btf_var_secinfos(sec) + var_idx; var = btf__type_by_id(obj->btf, vi->type); @@ -2327,7 +2334,34 @@ static int bpf_object__init_user_btf_map(struct bpf_object *obj, pr_debug("map '%s': at sec_idx %d, offset %zu.\n", map_name, map->sec_idx, map->sec_offset); - return parse_btf_map_def(obj, map, def, strict, false, pin_root_path); + err = parse_btf_map_def(map->name, obj->btf, def, strict, &map_def, &inner_def); + if (err) + return err; + + fill_map_from_def(map, &map_def); + + if (map_def.pinning == LIBBPF_PIN_BY_NAME) { + err = build_map_pin_path(map, pin_root_path); + if (err) { + pr_warn("map '%s': couldn't build pin path.\n", map->name); + return err; + } + } + + if (map_def.parts & MAP_DEF_INNER_MAP) { + map->inner_map = calloc(1, sizeof(*map->inner_map)); + if (!map->inner_map) + return -ENOMEM; + map->inner_map->fd = -1; + map->inner_map->name = malloc(strlen(map_name) + sizeof(".inner") + 1); + if (!map->inner_map->name) + return -ENOMEM; + sprintf(map->inner_map->name, "%s.inner", map_name); + + fill_map_from_def(map->inner_map, &inner_def); + } + + return 0; } static int bpf_object__init_user_btf_maps(struct bpf_object *obj, bool strict, diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h index 92b7eae10c6d..17883073710c 100644 --- a/tools/lib/bpf/libbpf_internal.h +++ b/tools/lib/bpf/libbpf_internal.h @@ -138,6 +138,38 @@ static inline __u32 btf_type_info(int kind, int vlen, int kflag) return (kflag << 31) | (kind << 24) | vlen; } +enum map_def_parts { + MAP_DEF_MAP_TYPE = 0x001, + MAP_DEF_KEY_TYPE = 0x002, + MAP_DEF_KEY_SIZE = 0x004, + MAP_DEF_VALUE_TYPE = 0x008, + MAP_DEF_VALUE_SIZE = 0x010, + MAP_DEF_MAX_ENTRIES = 0x020, + MAP_DEF_MAP_FLAGS = 0x040, + MAP_DEF_NUMA_NODE = 0x080, + MAP_DEF_PINNING = 0x100, + MAP_DEF_INNER_MAP = 0x200, + + MAP_DEF_ALL = 0x3ff, /* combination of all above */ +}; + +struct btf_map_def { + enum map_def_parts parts; + __u32 map_type; + __u32 key_type_id; + __u32 key_size; + __u32 value_type_id; + __u32 value_size; + __u32 max_entries; + __u32 map_flags; + __u32 numa_node; + __u32 pinning; +}; + +int parse_btf_map_def(const char *map_name, struct btf *btf, + const struct btf_type *def_t, bool strict, + struct btf_map_def *map_def, struct btf_map_def *inner_def); + void *libbpf_add_mem(void **data, size_t *cap_cnt, size_t elem_sz, size_t cur_cnt, size_t max_cnt, size_t add_cnt); int libbpf_ensure_mem(void **data, size_t *cap_cnt, size_t elem_sz, size_t need_cnt); From patchwork Fri Apr 16 20:23:54 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrii Nakryiko X-Patchwork-Id: 12208727 X-Patchwork-Delegate: bpf@iogearbox.net 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 4FAFEC43470 for ; Fri, 16 Apr 2021 20:24:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2E02A613CF for ; Fri, 16 Apr 2021 20:24:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245537AbhDPUY7 convert rfc822-to-8bit (ORCPT ); Fri, 16 Apr 2021 16:24:59 -0400 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:3336 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S245269AbhDPUY6 (ORCPT ); Fri, 16 Apr 2021 16:24:58 -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 13GKI3dg018903 for ; Fri, 16 Apr 2021 13:24:33 -0700 Received: from mail.thefacebook.com ([163.114.132.120]) by m0001303.ppops.net with ESMTP id 37yf0m0xhw-11 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Fri, 16 Apr 2021 13:24:32 -0700 Received: from intmgw001.05.ash9.facebook.com (2620:10d:c085:208::f) by mail.thefacebook.com (2620:10d:c085:11d::4) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Fri, 16 Apr 2021 13:24:28 -0700 Received: by devbig012.ftw2.facebook.com (Postfix, from userid 137359) id 7707C2ED4EE0; Fri, 16 Apr 2021 13:24:19 -0700 (PDT) From: Andrii Nakryiko To: , , , CC: , Subject: [PATCH v2 bpf-next 07/17] libbpf: factor out symtab and relos sanity checks Date: Fri, 16 Apr 2021 13:23:54 -0700 Message-ID: <20210416202404.3443623-8-andrii@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210416202404.3443623-1-andrii@kernel.org> References: <20210416202404.3443623-1-andrii@kernel.org> MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-GUID: yHmjIymrgHoguK6WINc_wI9yatCHg8cr X-Proofpoint-ORIG-GUID: yHmjIymrgHoguK6WINc_wI9yatCHg8cr X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.391,18.0.761 definitions=2021-04-16_09:2021-04-16,2021-04-16 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 lowpriorityscore=0 suspectscore=0 bulkscore=0 phishscore=0 spamscore=0 priorityscore=1501 malwarescore=0 impostorscore=0 mlxscore=0 clxscore=1015 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2104060000 definitions=main-2104160143 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net Factor out logic for sanity checking SHT_SYMTAB and SHT_REL sections into separate sections. They are already quite extensive and are suffering from too deep indentation. Subsequent changes will extend SYMTAB sanity checking further, so it's better to factor each into a separate function. No functional changes are intended. Signed-off-by: Andrii Nakryiko Acked-by: Yonghong Song --- tools/lib/bpf/linker.c | 233 ++++++++++++++++++++++------------------- 1 file changed, 127 insertions(+), 106 deletions(-) diff --git a/tools/lib/bpf/linker.c b/tools/lib/bpf/linker.c index 4e08bc07e635..0bb927226370 100644 --- a/tools/lib/bpf/linker.c +++ b/tools/lib/bpf/linker.c @@ -131,6 +131,8 @@ static int init_output_elf(struct bpf_linker *linker, const char *file); static int linker_load_obj_file(struct bpf_linker *linker, const char *filename, struct src_obj *obj); static int linker_sanity_check_elf(struct src_obj *obj); +static int linker_sanity_check_elf_symtab(struct src_obj *obj, struct src_sec *sec); +static int linker_sanity_check_elf_relos(struct src_obj *obj, struct src_sec *sec); static int linker_sanity_check_btf(struct src_obj *obj); static int linker_sanity_check_btf_ext(struct src_obj *obj); static int linker_fixup_btf(struct src_obj *obj); @@ -663,8 +665,8 @@ static bool is_pow_of_2(size_t x) static int linker_sanity_check_elf(struct src_obj *obj) { - struct src_sec *sec, *link_sec; - int i, j, n; + struct src_sec *sec; + int i, err; if (!obj->symtab_sec_idx) { pr_warn("ELF is missing SYMTAB section in %s\n", obj->filename); @@ -692,43 +694,11 @@ static int linker_sanity_check_elf(struct src_obj *obj) return -EINVAL; switch (sec->shdr->sh_type) { - case SHT_SYMTAB: { - Elf64_Sym *sym; - - if (sec->shdr->sh_entsize != sizeof(Elf64_Sym)) - return -EINVAL; - if (sec->shdr->sh_size % sec->shdr->sh_entsize != 0) - return -EINVAL; - - if (!sec->shdr->sh_link || sec->shdr->sh_link >= obj->sec_cnt) { - pr_warn("ELF SYMTAB section #%zu points to missing STRTAB section #%zu in %s\n", - sec->sec_idx, (size_t)sec->shdr->sh_link, obj->filename); - return -EINVAL; - } - link_sec = &obj->secs[sec->shdr->sh_link]; - if (link_sec->shdr->sh_type != SHT_STRTAB) { - pr_warn("ELF SYMTAB section #%zu points to invalid STRTAB section #%zu in %s\n", - sec->sec_idx, (size_t)sec->shdr->sh_link, obj->filename); - return -EINVAL; - } - - n = sec->shdr->sh_size / sec->shdr->sh_entsize; - sym = sec->data->d_buf; - for (j = 0; j < n; j++, sym++) { - if (sym->st_shndx - && sym->st_shndx < SHN_LORESERVE - && sym->st_shndx >= obj->sec_cnt) { - pr_warn("ELF sym #%d in section #%zu points to missing section #%zu in %s\n", - j, sec->sec_idx, (size_t)sym->st_shndx, obj->filename); - return -EINVAL; - } - if (ELF64_ST_TYPE(sym->st_info) == STT_SECTION) { - if (sym->st_value != 0) - return -EINVAL; - } - } + case SHT_SYMTAB: + err = linker_sanity_check_elf_symtab(obj, sec); + if (err) + return err; break; - } case SHT_STRTAB: break; case SHT_PROGBITS: @@ -739,87 +709,138 @@ static int linker_sanity_check_elf(struct src_obj *obj) break; case SHT_NOBITS: break; - case SHT_REL: { - Elf64_Rel *relo; - struct src_sec *sym_sec; + case SHT_REL: + err = linker_sanity_check_elf_relos(obj, sec); + if (err) + return err; + break; + case SHT_LLVM_ADDRSIG: + break; + default: + pr_warn("ELF section #%zu (%s) has unrecognized type %zu in %s\n", + sec->sec_idx, sec->sec_name, (size_t)sec->shdr->sh_type, obj->filename); + return -EINVAL; + } + } - if (sec->shdr->sh_entsize != sizeof(Elf64_Rel)) - return -EINVAL; - if (sec->shdr->sh_size % sec->shdr->sh_entsize != 0) - return -EINVAL; + return 0; +} - /* SHT_REL's sh_link should point to SYMTAB */ - if (sec->shdr->sh_link != obj->symtab_sec_idx) { - pr_warn("ELF relo section #%zu points to invalid SYMTAB section #%zu in %s\n", - sec->sec_idx, (size_t)sec->shdr->sh_link, obj->filename); - return -EINVAL; - } +static int linker_sanity_check_elf_symtab(struct src_obj *obj, struct src_sec *sec) +{ + struct src_sec *link_sec; + Elf64_Sym *sym; + int i, n; - /* SHT_REL's sh_info points to relocated section */ - if (!sec->shdr->sh_info || sec->shdr->sh_info >= obj->sec_cnt) { - pr_warn("ELF relo section #%zu points to missing section #%zu in %s\n", - sec->sec_idx, (size_t)sec->shdr->sh_info, obj->filename); - return -EINVAL; - } - link_sec = &obj->secs[sec->shdr->sh_info]; + if (sec->shdr->sh_entsize != sizeof(Elf64_Sym)) + return -EINVAL; + if (sec->shdr->sh_size % sec->shdr->sh_entsize != 0) + return -EINVAL; + + if (!sec->shdr->sh_link || sec->shdr->sh_link >= obj->sec_cnt) { + pr_warn("ELF SYMTAB section #%zu points to missing STRTAB section #%zu in %s\n", + sec->sec_idx, (size_t)sec->shdr->sh_link, obj->filename); + return -EINVAL; + } + link_sec = &obj->secs[sec->shdr->sh_link]; + if (link_sec->shdr->sh_type != SHT_STRTAB) { + pr_warn("ELF SYMTAB section #%zu points to invalid STRTAB section #%zu in %s\n", + sec->sec_idx, (size_t)sec->shdr->sh_link, obj->filename); + return -EINVAL; + } - /* .rel -> pattern is followed */ - if (strncmp(sec->sec_name, ".rel", sizeof(".rel") - 1) != 0 - || strcmp(sec->sec_name + sizeof(".rel") - 1, link_sec->sec_name) != 0) { - pr_warn("ELF relo section #%zu name has invalid name in %s\n", - sec->sec_idx, obj->filename); + n = sec->shdr->sh_size / sec->shdr->sh_entsize; + sym = sec->data->d_buf; + for (i = 0; i < n; i++, sym++) { + if (sym->st_shndx + && sym->st_shndx < SHN_LORESERVE + && sym->st_shndx >= obj->sec_cnt) { + pr_warn("ELF sym #%d in section #%zu points to missing section #%zu in %s\n", + i, sec->sec_idx, (size_t)sym->st_shndx, obj->filename); + return -EINVAL; + } + if (ELF64_ST_TYPE(sym->st_info) == STT_SECTION) { + if (sym->st_value != 0) return -EINVAL; - } + continue; + } + } - /* don't further validate relocations for ignored sections */ - if (link_sec->skipped) - break; + return 0; +} - /* relocatable section is data or instructions */ - if (link_sec->shdr->sh_type != SHT_PROGBITS - && link_sec->shdr->sh_type != SHT_NOBITS) { - pr_warn("ELF relo section #%zu points to invalid section #%zu in %s\n", - sec->sec_idx, (size_t)sec->shdr->sh_info, obj->filename); - return -EINVAL; - } +static int linker_sanity_check_elf_relos(struct src_obj *obj, struct src_sec *sec) +{ + struct src_sec *link_sec, *sym_sec; + Elf64_Rel *relo; + int i, n; - /* check sanity of each relocation */ - n = sec->shdr->sh_size / sec->shdr->sh_entsize; - relo = sec->data->d_buf; - sym_sec = &obj->secs[obj->symtab_sec_idx]; - for (j = 0; j < n; j++, relo++) { - size_t sym_idx = ELF64_R_SYM(relo->r_info); - size_t sym_type = ELF64_R_TYPE(relo->r_info); - - if (sym_type != R_BPF_64_64 && sym_type != R_BPF_64_32) { - pr_warn("ELF relo #%d in section #%zu has unexpected type %zu in %s\n", - j, sec->sec_idx, sym_type, obj->filename); - return -EINVAL; - } + if (sec->shdr->sh_entsize != sizeof(Elf64_Rel)) + return -EINVAL; + if (sec->shdr->sh_size % sec->shdr->sh_entsize != 0) + return -EINVAL; - if (!sym_idx || sym_idx * sizeof(Elf64_Sym) >= sym_sec->shdr->sh_size) { - pr_warn("ELF relo #%d in section #%zu points to invalid symbol #%zu in %s\n", - j, sec->sec_idx, sym_idx, obj->filename); - return -EINVAL; - } + /* SHT_REL's sh_link should point to SYMTAB */ + if (sec->shdr->sh_link != obj->symtab_sec_idx) { + pr_warn("ELF relo section #%zu points to invalid SYMTAB section #%zu in %s\n", + sec->sec_idx, (size_t)sec->shdr->sh_link, obj->filename); + return -EINVAL; + } - if (link_sec->shdr->sh_flags & SHF_EXECINSTR) { - if (relo->r_offset % sizeof(struct bpf_insn) != 0) { - pr_warn("ELF relo #%d in section #%zu points to missing symbol #%zu in %s\n", - j, sec->sec_idx, sym_idx, obj->filename); - return -EINVAL; - } - } - } - break; + /* SHT_REL's sh_info points to relocated section */ + if (!sec->shdr->sh_info || sec->shdr->sh_info >= obj->sec_cnt) { + pr_warn("ELF relo section #%zu points to missing section #%zu in %s\n", + sec->sec_idx, (size_t)sec->shdr->sh_info, obj->filename); + return -EINVAL; + } + link_sec = &obj->secs[sec->shdr->sh_info]; + + /* .rel -> pattern is followed */ + if (strncmp(sec->sec_name, ".rel", sizeof(".rel") - 1) != 0 + || strcmp(sec->sec_name + sizeof(".rel") - 1, link_sec->sec_name) != 0) { + pr_warn("ELF relo section #%zu name has invalid name in %s\n", + sec->sec_idx, obj->filename); + return -EINVAL; + } + + /* don't further validate relocations for ignored sections */ + if (link_sec->skipped) + return 0; + + /* relocatable section is data or instructions */ + if (link_sec->shdr->sh_type != SHT_PROGBITS && link_sec->shdr->sh_type != SHT_NOBITS) { + pr_warn("ELF relo section #%zu points to invalid section #%zu in %s\n", + sec->sec_idx, (size_t)sec->shdr->sh_info, obj->filename); + return -EINVAL; + } + + /* check sanity of each relocation */ + n = sec->shdr->sh_size / sec->shdr->sh_entsize; + relo = sec->data->d_buf; + sym_sec = &obj->secs[obj->symtab_sec_idx]; + for (i = 0; i < n; i++, relo++) { + size_t sym_idx = ELF64_R_SYM(relo->r_info); + size_t sym_type = ELF64_R_TYPE(relo->r_info); + + if (sym_type != R_BPF_64_64 && sym_type != R_BPF_64_32) { + pr_warn("ELF relo #%d in section #%zu has unexpected type %zu in %s\n", + i, sec->sec_idx, sym_type, obj->filename); + return -EINVAL; } - case SHT_LLVM_ADDRSIG: - break; - default: - pr_warn("ELF section #%zu (%s) has unrecognized type %zu in %s\n", - sec->sec_idx, sec->sec_name, (size_t)sec->shdr->sh_type, obj->filename); + + if (!sym_idx || sym_idx * sizeof(Elf64_Sym) >= sym_sec->shdr->sh_size) { + pr_warn("ELF relo #%d in section #%zu points to invalid symbol #%zu in %s\n", + i, sec->sec_idx, sym_idx, obj->filename); return -EINVAL; } + + if (link_sec->shdr->sh_flags & SHF_EXECINSTR) { + if (relo->r_offset % sizeof(struct bpf_insn) != 0) { + pr_warn("ELF relo #%d in section #%zu points to missing symbol #%zu in %s\n", + i, sec->sec_idx, sym_idx, obj->filename); + return -EINVAL; + } + } } return 0; From patchwork Fri Apr 16 20:23:55 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrii Nakryiko X-Patchwork-Id: 12208725 X-Patchwork-Delegate: bpf@iogearbox.net 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 90B3AC43461 for ; Fri, 16 Apr 2021 20:24:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6D758613CE for ; Fri, 16 Apr 2021 20:24:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343492AbhDPUY5 convert rfc822-to-8bit (ORCPT ); Fri, 16 Apr 2021 16:24:57 -0400 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:28936 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245714AbhDPUY4 (ORCPT ); Fri, 16 Apr 2021 16:24:56 -0400 Received: from pps.filterd (m0109333.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.43/8.16.0.43) with SMTP id 13GKKKqD024106 for ; Fri, 16 Apr 2021 13:24:31 -0700 Received: from mail.thefacebook.com ([163.114.132.120]) by mx0a-00082601.pphosted.com with ESMTP id 37wv9qr9rx-2 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Fri, 16 Apr 2021 13:24:30 -0700 Received: from intmgw002.25.frc3.facebook.com (2620:10d:c085:108::4) by mail.thefacebook.com (2620:10d:c085:21d::5) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Fri, 16 Apr 2021 13:24:29 -0700 Received: by devbig012.ftw2.facebook.com (Postfix, from userid 137359) id 7B3DA2ED4EE0; Fri, 16 Apr 2021 13:24:21 -0700 (PDT) From: Andrii Nakryiko To: , , , CC: , Subject: [PATCH v2 bpf-next 08/17] libbpf: make few internal helpers available outside of libbpf.c Date: Fri, 16 Apr 2021 13:23:55 -0700 Message-ID: <20210416202404.3443623-9-andrii@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210416202404.3443623-1-andrii@kernel.org> References: <20210416202404.3443623-1-andrii@kernel.org> MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-GUID: TyNix1rw7KNZnbWBv3CGUGmn5xFOT7nN X-Proofpoint-ORIG-GUID: TyNix1rw7KNZnbWBv3CGUGmn5xFOT7nN X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.391,18.0.761 definitions=2021-04-16_09:2021-04-16,2021-04-16 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 spamscore=0 suspectscore=0 clxscore=1015 adultscore=0 mlxscore=0 lowpriorityscore=0 malwarescore=0 impostorscore=0 phishscore=0 priorityscore=1501 mlxlogscore=999 bulkscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2104060000 definitions=main-2104160143 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net Make skip_mods_and_typedefs(), btf_kind_str(), and btf_func_linkage() helpers available outside of libbpf.c, to be used by static linker code. Also do few cleanups (error code fixes, comment clean up, etc) that don't deserve their own commit. Signed-off-by: Andrii Nakryiko Acked-by: Yonghong Song --- tools/lib/bpf/libbpf.c | 13 +++---------- tools/lib/bpf/libbpf_internal.h | 7 +++++++ tools/lib/bpf/linker.c | 14 ++++++-------- 3 files changed, 16 insertions(+), 18 deletions(-) diff --git a/tools/lib/bpf/libbpf.c b/tools/lib/bpf/libbpf.c index f6f4126389ac..82b1946a0802 100644 --- a/tools/lib/bpf/libbpf.c +++ b/tools/lib/bpf/libbpf.c @@ -69,8 +69,6 @@ #define __printf(a, b) __attribute__((format(printf, a, b))) static struct bpf_map *bpf_object__add_map(struct bpf_object *obj); -static const struct btf_type * -skip_mods_and_typedefs(const struct btf *btf, __u32 id, __u32 *res_id); static bool prog_is_subprog(const struct bpf_object *obj, const struct bpf_program *prog); static int __base_pr(enum libbpf_print_level level, const char *format, @@ -1906,7 +1904,7 @@ static int bpf_object__init_user_maps(struct bpf_object *obj, bool strict) return 0; } -static const struct btf_type * +const struct btf_type * skip_mods_and_typedefs(const struct btf *btf, __u32 id, __u32 *res_id) { const struct btf_type *t = btf__type_by_id(btf, id); @@ -1961,16 +1959,11 @@ static const char *__btf_kind_str(__u16 kind) } } -static const char *btf_kind_str(const struct btf_type *t) +const char *btf_kind_str(const struct btf_type *t) { return __btf_kind_str(btf_kind(t)); } -static enum btf_func_linkage btf_func_linkage(const struct btf_type *t) -{ - return (enum btf_func_linkage)BTF_INFO_VLEN(t->info); -} - /* * Fetch integer attribute of BTF map definition. Such attributes are * represented using a pointer to an array, in which dimensionality of array @@ -7035,7 +7028,7 @@ static bool insn_is_helper_call(struct bpf_insn *insn, enum bpf_func_id *func_id return false; } -static int bpf_object__sanitize_prog(struct bpf_object* obj, struct bpf_program *prog) +static int bpf_object__sanitize_prog(struct bpf_object *obj, struct bpf_program *prog) { struct bpf_insn *insn = prog->insns; enum bpf_func_id func_id; diff --git a/tools/lib/bpf/libbpf_internal.h b/tools/lib/bpf/libbpf_internal.h index 17883073710c..ee426226928f 100644 --- a/tools/lib/bpf/libbpf_internal.h +++ b/tools/lib/bpf/libbpf_internal.h @@ -132,6 +132,13 @@ struct btf; struct btf_type; struct btf_type *btf_type_by_id(struct btf *btf, __u32 type_id); +const char *btf_kind_str(const struct btf_type *t); +const struct btf_type *skip_mods_and_typedefs(const struct btf *btf, __u32 id, __u32 *res_id); + +static inline enum btf_func_linkage btf_func_linkage(const struct btf_type *t) +{ + return (enum btf_func_linkage)(int)btf_vlen(t); +} static inline __u32 btf_type_info(int kind, int vlen, int kflag) { diff --git a/tools/lib/bpf/linker.c b/tools/lib/bpf/linker.c index 0bb927226370..1263641e8b97 100644 --- a/tools/lib/bpf/linker.c +++ b/tools/lib/bpf/linker.c @@ -123,9 +123,7 @@ struct bpf_linker { }; #define pr_warn_elf(fmt, ...) \ -do { \ - libbpf_print(LIBBPF_WARN, "libbpf: " fmt ": %s\n", ##__VA_ARGS__, elf_errmsg(-1)); \ -} while (0) + libbpf_print(LIBBPF_WARN, "libbpf: " fmt ": %s\n", ##__VA_ARGS__, elf_errmsg(-1)) static int init_output_elf(struct bpf_linker *linker, const char *file); @@ -284,7 +282,7 @@ static int init_output_elf(struct bpf_linker *linker, const char *file) /* ELF header */ linker->elf_hdr = elf64_newehdr(linker->elf); - if (!linker->elf_hdr){ + if (!linker->elf_hdr) { pr_warn_elf("failed to create ELF header"); return -EINVAL; } @@ -925,13 +923,13 @@ static int init_sec(struct bpf_linker *linker, struct dst_sec *dst_sec, struct s scn = elf_newscn(linker->elf); if (!scn) - return -1; + return -ENOMEM; data = elf_newdata(scn); if (!data) - return -1; + return -ENOMEM; shdr = elf64_getshdr(scn); if (!shdr) - return -1; + return -ENOMEM; dst_sec->scn = scn; dst_sec->shdr = shdr; @@ -1221,7 +1219,7 @@ static int linker_append_elf_relos(struct bpf_linker *linker, struct src_obj *ob return err; } } else if (!secs_match(dst_sec, src_sec)) { - pr_warn("Secs %s are not compatible\n", src_sec->sec_name); + pr_warn("sections %s are not compatible\n", src_sec->sec_name); return -1; } From patchwork Fri Apr 16 20:23:56 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrii Nakryiko X-Patchwork-Id: 12208719 X-Patchwork-Delegate: bpf@iogearbox.net 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=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 5D0D9C43460 for ; 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Fri, 16 Apr 2021 13:24:25 -0700 Received: by devbig012.ftw2.facebook.com (Postfix, from userid 137359) id 844192ED4EE0; Fri, 16 Apr 2021 13:24:23 -0700 (PDT) From: Andrii Nakryiko To: , , , CC: , Subject: [PATCH v2 bpf-next 09/17] libbpf: extend sanity checking ELF symbols with externs validation Date: Fri, 16 Apr 2021 13:23:56 -0700 Message-ID: <20210416202404.3443623-10-andrii@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210416202404.3443623-1-andrii@kernel.org> References: <20210416202404.3443623-1-andrii@kernel.org> MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-GUID: Pk3gcADb7XQYdI1yKVLqppcqTMRmJYYS X-Proofpoint-ORIG-GUID: Pk3gcADb7XQYdI1yKVLqppcqTMRmJYYS X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.391,18.0.761 definitions=2021-04-16_09:2021-04-16,2021-04-16 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 lowpriorityscore=0 suspectscore=0 bulkscore=0 phishscore=0 spamscore=0 priorityscore=1501 malwarescore=0 impostorscore=0 mlxscore=0 clxscore=1015 mlxlogscore=999 adultscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2104060000 definitions=main-2104160143 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net Add logic to validate extern symbols, plus some other minor extra checks, like ELF symbol #0 validation, general symbol visibility and binding validations. Signed-off-by: Andrii Nakryiko --- tools/lib/bpf/linker.c | 43 +++++++++++++++++++++++++++++++++--------- 1 file changed, 34 insertions(+), 9 deletions(-) diff --git a/tools/lib/bpf/linker.c b/tools/lib/bpf/linker.c index 1263641e8b97..283249df9831 100644 --- a/tools/lib/bpf/linker.c +++ b/tools/lib/bpf/linker.c @@ -750,14 +750,39 @@ static int linker_sanity_check_elf_symtab(struct src_obj *obj, struct src_sec *s n = sec->shdr->sh_size / sec->shdr->sh_entsize; sym = sec->data->d_buf; for (i = 0; i < n; i++, sym++) { - if (sym->st_shndx - && sym->st_shndx < SHN_LORESERVE - && sym->st_shndx >= obj->sec_cnt) { + int sym_type = ELF64_ST_TYPE(sym->st_info); + int sym_bind = ELF64_ST_BIND(sym->st_info); + + if (i == 0) { + if (sym->st_name != 0 || sym->st_info != 0 + || sym->st_other != 0 || sym->st_shndx != 0 + || sym->st_value != 0 || sym->st_size != 0) { + pr_warn("ELF sym #0 is invalid in %s\n", obj->filename); + return -EINVAL; + } + continue; + } + if (sym_bind != STB_LOCAL && sym_bind != STB_GLOBAL && sym_bind != STB_WEAK) { + pr_warn("ELF sym #%d is section #%zu has unsupported symbol binding %d\n", + i, sec->sec_idx, sym_bind); + return -EINVAL; + } + if (sym->st_shndx == 0) { + if (sym_type != STT_NOTYPE || sym_bind == STB_LOCAL + || sym->st_value != 0 || sym->st_size != 0) { + pr_warn("ELF sym #%d is invalid extern symbol in %s\n", + i, obj->filename); + + return -EINVAL; + } + continue; + } + if (sym->st_shndx < SHN_LORESERVE && sym->st_shndx >= obj->sec_cnt) { pr_warn("ELF sym #%d in section #%zu points to missing section #%zu in %s\n", i, sec->sec_idx, (size_t)sym->st_shndx, obj->filename); return -EINVAL; } - if (ELF64_ST_TYPE(sym->st_info) == STT_SECTION) { + if (sym_type == STT_SECTION) { if (sym->st_value != 0) return -EINVAL; continue; @@ -1135,16 +1160,16 @@ static int linker_append_elf_syms(struct bpf_linker *linker, struct src_obj *obj size_t dst_sym_idx; int name_off; - /* we already have all-zero initial symbol */ - if (sym->st_name == 0 && sym->st_info == 0 && - sym->st_other == 0 && sym->st_shndx == SHN_UNDEF && - sym->st_value == 0 && sym->st_size ==0) + /* We already validated all-zero symbol #0 and we already + * appended it preventively to the final SYMTAB, so skip it. + */ + if (i == 0) continue; sym_name = elf_strptr(obj->elf, str_sec_idx, sym->st_name); if (!sym_name) { pr_warn("can't fetch symbol name for symbol #%d in '%s'\n", i, obj->filename); - return -1; + return -EINVAL; } if (sym->st_shndx && sym->st_shndx < SHN_LORESERVE) { From patchwork Fri Apr 16 20:23:57 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrii Nakryiko X-Patchwork-Id: 12208721 X-Patchwork-Delegate: bpf@iogearbox.net 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=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 05897C433B4 for ; Fri, 16 Apr 2021 20:24:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DBE76613CD for ; 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Fri, 16 Apr 2021 13:24:30 -0700 Received: by devbig012.ftw2.facebook.com (Postfix, from userid 137359) id 882B52ED4EE0; Fri, 16 Apr 2021 13:24:25 -0700 (PDT) From: Andrii Nakryiko To: , , , CC: , Subject: [PATCH v2 bpf-next 10/17] libbpf: tighten BTF type ID rewriting with error checking Date: Fri, 16 Apr 2021 13:23:57 -0700 Message-ID: <20210416202404.3443623-11-andrii@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210416202404.3443623-1-andrii@kernel.org> References: <20210416202404.3443623-1-andrii@kernel.org> MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-ORIG-GUID: vk1krfk6x9ItOEsuyK-oqLLebgjL0Z3_ X-Proofpoint-GUID: vk1krfk6x9ItOEsuyK-oqLLebgjL0Z3_ X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.391,18.0.761 definitions=2021-04-16_09:2021-04-16,2021-04-16 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 malwarescore=0 spamscore=0 priorityscore=1501 phishscore=0 adultscore=0 lowpriorityscore=0 bulkscore=0 mlxscore=0 suspectscore=0 impostorscore=0 mlxlogscore=871 clxscore=1034 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2104060000 definitions=main-2104160143 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net It should never fail, but if it does, it's better to know about this rather than end up with nonsensical type IDs. Signed-off-by: Andrii Nakryiko --- tools/lib/bpf/linker.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/tools/lib/bpf/linker.c b/tools/lib/bpf/linker.c index 283249df9831..d5dc1d401f57 100644 --- a/tools/lib/bpf/linker.c +++ b/tools/lib/bpf/linker.c @@ -1423,6 +1423,15 @@ static int linker_fixup_btf(struct src_obj *obj) static int remap_type_id(__u32 *type_id, void *ctx) { int *id_map = ctx; + int new_id = id_map[*type_id]; + + if (*type_id == 0) + return 0; + + if (new_id == 0) { + pr_warn("failed to find new ID mapping for original BTF type ID %u\n", *type_id); + return -EINVAL; + } *type_id = id_map[*type_id]; From patchwork Fri Apr 16 20:23:58 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrii Nakryiko X-Patchwork-Id: 12208723 X-Patchwork-Delegate: bpf@iogearbox.net 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=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 61025C433ED for ; Fri, 16 Apr 2021 20:24:32 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 333ED61166 for ; Fri, 16 Apr 2021 20:24:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S245717AbhDPUY4 convert rfc822-to-8bit (ORCPT ); Fri, 16 Apr 2021 16:24:56 -0400 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:21132 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S245712AbhDPUYz (ORCPT ); Fri, 16 Apr 2021 16:24:55 -0400 Received: from pps.filterd (m0044010.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.43/8.16.0.43) with SMTP id 13GKLVlu021285 for ; Fri, 16 Apr 2021 13:24:30 -0700 Received: from mail.thefacebook.com ([163.114.132.120]) by mx0a-00082601.pphosted.com with ESMTP id 37yb9y2dqn-3 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Fri, 16 Apr 2021 13:24:30 -0700 Received: from intmgw001.37.frc1.facebook.com (2620:10d:c085:208::11) by mail.thefacebook.com (2620:10d:c085:11d::7) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Fri, 16 Apr 2021 13:24:29 -0700 Received: by devbig012.ftw2.facebook.com (Postfix, from userid 137359) id 953052ED4EE0; Fri, 16 Apr 2021 13:24:27 -0700 (PDT) From: Andrii Nakryiko To: , , , CC: , Subject: [PATCH v2 bpf-next 11/17] libbpf: add linker extern resolution support for functions and global variables Date: Fri, 16 Apr 2021 13:23:58 -0700 Message-ID: <20210416202404.3443623-12-andrii@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210416202404.3443623-1-andrii@kernel.org> References: <20210416202404.3443623-1-andrii@kernel.org> MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-ORIG-GUID: R-hkU6PQZGetbtg_a0Y6t7LIwF76GM-y X-Proofpoint-GUID: R-hkU6PQZGetbtg_a0Y6t7LIwF76GM-y X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.391,18.0.761 definitions=2021-04-16_09:2021-04-16,2021-04-16 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 malwarescore=0 spamscore=0 priorityscore=1501 phishscore=0 adultscore=0 lowpriorityscore=0 bulkscore=0 mlxscore=0 suspectscore=0 impostorscore=0 mlxlogscore=999 clxscore=1015 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2104060000 definitions=main-2104160143 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net Add BPF static linker logic to resolve extern variables and functions across multiple linked together BPF object files. For that, linker maintains a separate list of struct glob_sym structures, which keeps track of few pieces of metadata (is it extern or resolved global, is it a weak symbol, which ELF section it belongs to, etc) and ties together BTF type info and ELF symbol information and keeps them in sync. With adding support for extern variables/funcs, it's now possible for some sections to contain both extern and non-extern definitions. This means that some sections may start out as ephemeral (if only externs are present and thus there is not corresponding ELF section), but will be "upgraded" to actual ELF section as symbols are resolved or new non-extern definitions are appended. Additional care is taken to not duplicate extern entries in sections like .kconfig and .ksyms. Given libbpf requires BTF type to always be present for .kconfig/.ksym externs, linker extends this requirement to all the externs, even those that are supposed to be resolved during static linking and which won't be visible to libbpf. With BTF information always present, static linker will check not just ELF symbol matches, but entire BTF type signature match as well. That logic is stricter that BPF CO-RE checks. It probably should be re-used by .ksym resolution logic in libbpf as well, but that's left for follow up patches. To make it unnecessary to rewrite ELF symbols and minimize BTF type rewriting/removal, ELF symbols that correspond to externs initially will be updated in place once they are resolved. Similarly for BTF type info, VAR/FUNC and var_secinfo's (sec_vars in struct bpf_linker) are staying stable, but types they point to might get replaced when extern is resolved. This might leave some left-over types (even though we try to minimize this for common cases of having extern funcs with not argument names vs concrete function with names properly specified). That can be addresses later with a generic BTF garbage collection. That's left for a follow up as well. Given BTF type appending phase is separate from ELF symbol appending/resolution, special struct glob_sym->underlying_btf_id variable is used to communicate resolution and rewrite decisions. 0 means underlying_btf_id needs to be appended (it's not yet in final linker->btf), <0 values are used for temporary storage of source BTF type ID (not yet rewritten), so -glob_sym->underlying_btf_id is BTF type id in obj-btf. But by the end of linker_append_btf() phase, that underlying_btf_id will be remapped and will always be > 0. This is the uglies part of the whole process, but keeps the other parts much simpler due to stability of sec_var and VAR/FUNC types, as well as ELF symbol, so please keep that in mind while reviewing. BTF-defined maps require some extra custom logic and is addressed separate in the next patch, so that to keep this one smaller and easier to review. Signed-off-by: Andrii Nakryiko --- tools/lib/bpf/linker.c | 844 ++++++++++++++++++++++++++++++++++++++--- 1 file changed, 785 insertions(+), 59 deletions(-) diff --git a/tools/lib/bpf/linker.c b/tools/lib/bpf/linker.c index d5dc1d401f57..67d2d06e3cb6 100644 --- a/tools/lib/bpf/linker.c +++ b/tools/lib/bpf/linker.c @@ -22,6 +22,8 @@ #include "libbpf_internal.h" #include "strset.h" +#define BTF_EXTERN_SEC ".extern" + struct src_sec { const char *sec_name; /* positional (not necessarily ELF) index in an array of sections */ @@ -74,11 +76,36 @@ struct btf_ext_sec_data { void *recs; }; +struct glob_sym { + /* ELF symbol index */ + int sym_idx; + /* associated section id for .ksyms, .kconfig, etc, but not .extern */ + int sec_id; + /* extern name offset in STRTAB */ + int name_off; + /* optional associated BTF type ID */ + int btf_id; + /* BTF type ID to which VAR/FUNC type is pointing to; used for + * rewriting types when extern VAR/FUNC is resolved to a concrete + * definition + */ + int underlying_btf_id; + /* sec_var index in the corresponding dst_sec, if exists */ + int var_idx; + + /* extern or resolved/global symbol */ + bool is_extern; + /* weak or strong symbol, never goes back from strong to weak */ + bool is_weak; +}; + struct dst_sec { char *sec_name; /* positional (not necessarily ELF) index in an array of sections */ int id; + bool ephemeral; + /* ELF info */ size_t sec_idx; Elf_Scn *scn; @@ -120,6 +147,10 @@ struct bpf_linker { struct btf *btf; struct btf_ext *btf_ext; + + /* global (including extern) ELF symbols */ + int glob_sym_cnt; + struct glob_sym *glob_syms; }; #define pr_warn_elf(fmt, ...) \ @@ -136,6 +167,8 @@ static int linker_sanity_check_btf_ext(struct src_obj *obj); static int linker_fixup_btf(struct src_obj *obj); static int linker_append_sec_data(struct bpf_linker *linker, struct src_obj *obj); static int linker_append_elf_syms(struct bpf_linker *linker, struct src_obj *obj); +static int linker_append_elf_sym(struct bpf_linker *linker, struct src_obj *obj, + Elf64_Sym *sym, const char *sym_name, int src_sym_idx); static int linker_append_elf_relos(struct bpf_linker *linker, struct src_obj *obj); static int linker_append_btf(struct bpf_linker *linker, struct src_obj *obj); static int linker_append_btf_ext(struct bpf_linker *linker, struct src_obj *obj); @@ -941,6 +974,7 @@ static int init_sec(struct bpf_linker *linker, struct dst_sec *dst_sec, struct s dst_sec->sec_sz = 0; dst_sec->sec_idx = 0; + dst_sec->ephemeral = src_sec->ephemeral; /* ephemeral sections are just thin section shells lacking most parts */ if (src_sec->ephemeral) @@ -1004,6 +1038,9 @@ static struct dst_sec *find_dst_sec_by_name(struct bpf_linker *linker, const cha static bool secs_match(struct dst_sec *dst, struct src_sec *src) { + if (dst->ephemeral || src->ephemeral) + return true; + if (dst->shdr->sh_type != src->shdr->sh_type) { pr_warn("sec %s types mismatch\n", dst->sec_name); return false; @@ -1029,13 +1066,33 @@ static bool sec_content_is_same(struct dst_sec *dst_sec, struct src_sec *src_sec return true; } -static int extend_sec(struct dst_sec *dst, struct src_sec *src) +static int extend_sec(struct bpf_linker *linker, struct dst_sec *dst, struct src_sec *src) { void *tmp; - size_t dst_align = dst->shdr->sh_addralign; - size_t src_align = src->shdr->sh_addralign; + size_t dst_align, src_align; size_t dst_align_sz, dst_final_sz; + int err; + + /* Ephemeral source section doesn't contribute anything to ELF + * section data. + */ + if (src->ephemeral) + return 0; + + /* Some sections (like .maps) can contain both externs (and thus be + * ephemeral) and non-externs (map definitions). So it's possible that + * it has to be "upgraded" from ephemeral to non-ephemeral when the + * first non-ephemeral entity appears. In such case, we add ELF + * section, data, etc. + */ + if (dst->ephemeral) { + err = init_sec(linker, dst, src); + if (err) + return err; + } + dst_align = dst->shdr->sh_addralign; + src_align = src->shdr->sh_addralign; if (dst_align == 0) dst_align = 1; if (dst_align < src_align) @@ -1131,10 +1188,7 @@ static int linker_append_sec_data(struct bpf_linker *linker, struct src_obj *obj /* record mapped section index */ src_sec->dst_id = dst_sec->id; - if (src_sec->ephemeral) - continue; - - err = extend_sec(dst_sec, src_sec); + err = extend_sec(linker, dst_sec, src_sec); if (err) return err; } @@ -1145,21 +1199,16 @@ static int linker_append_sec_data(struct bpf_linker *linker, struct src_obj *obj static int linker_append_elf_syms(struct bpf_linker *linker, struct src_obj *obj) { struct src_sec *symtab = &obj->secs[obj->symtab_sec_idx]; - Elf64_Sym *sym = symtab->data->d_buf, *dst_sym; - int i, n = symtab->shdr->sh_size / symtab->shdr->sh_entsize; + Elf64_Sym *sym = symtab->data->d_buf; + int i, n = symtab->shdr->sh_size / symtab->shdr->sh_entsize, err; int str_sec_idx = symtab->shdr->sh_link; + const char *sym_name; obj->sym_map = calloc(n + 1, sizeof(*obj->sym_map)); if (!obj->sym_map) return -ENOMEM; for (i = 0; i < n; i++, sym++) { - struct src_sec *src_sec = NULL; - struct dst_sec *dst_sec = NULL; - const char *sym_name; - size_t dst_sym_idx; - int name_off; - /* We already validated all-zero symbol #0 and we already * appended it preventively to the final SYMTAB, so skip it. */ @@ -1172,41 +1221,623 @@ static int linker_append_elf_syms(struct bpf_linker *linker, struct src_obj *obj return -EINVAL; } - if (sym->st_shndx && sym->st_shndx < SHN_LORESERVE) { - src_sec = &obj->secs[sym->st_shndx]; - if (src_sec->skipped) + err = linker_append_elf_sym(linker, obj, sym, sym_name, i); + if (err) + return err; + } + + return 0; +} + +static Elf64_Sym *get_sym_by_idx(struct bpf_linker *linker, size_t sym_idx) +{ + struct dst_sec *symtab = &linker->secs[linker->symtab_sec_idx]; + Elf64_Sym *syms = symtab->raw_data; + + return &syms[sym_idx]; +} + +static struct glob_sym *find_glob_sym(struct bpf_linker *linker, const char *sym_name) +{ + struct glob_sym *glob_sym; + const char *name; + int i; + + for (i = 0; i < linker->glob_sym_cnt; i++) { + glob_sym = &linker->glob_syms[i]; + name = strset__data(linker->strtab_strs) + glob_sym->name_off; + + if (strcmp(name, sym_name) == 0) + return glob_sym; + } + + return NULL; +} + +static struct glob_sym *add_glob_sym(struct bpf_linker *linker) +{ + struct glob_sym *syms, *sym; + + syms = libbpf_reallocarray(linker->glob_syms, linker->glob_sym_cnt + 1, + sizeof(*linker->glob_syms)); + if (!syms) + return NULL; + + sym = &syms[linker->glob_sym_cnt]; + memset(sym, 0, sizeof(*sym)); + sym->var_idx = -1; + + linker->glob_syms = syms; + linker->glob_sym_cnt++; + + return sym; +} + +static bool glob_sym_btf_matches(const char *sym_name, bool exact, + const struct btf *btf1, __u32 id1, + const struct btf *btf2, __u32 id2) +{ + const struct btf_type *t1, *t2; + bool is_static1, is_static2; + const char *n1, *n2; + int i, n; + +recur: + n1 = n2 = NULL; + t1 = skip_mods_and_typedefs(btf1, id1, &id1); + t2 = skip_mods_and_typedefs(btf2, id2, &id2); + + /* check if only one side is FWD, otherwise handle with common logic */ + if (!exact && btf_is_fwd(t1) != btf_is_fwd(t2)) { + n1 = btf__str_by_offset(btf1, t1->name_off); + n2 = btf__str_by_offset(btf2, t2->name_off); + if (strcmp(n1, n2) != 0) { + pr_warn("global '%s': incompatible forward declaration names '%s' and '%s'\n", + sym_name, n1, n2); + return false; + } + /* validate if FWD kind matches concrete kind */ + if (btf_is_fwd(t1)) { + if (btf_kflag(t1) && btf_is_union(t2)) + return true; + if (!btf_kflag(t1) && btf_is_struct(t2)) + return true; + pr_warn("global '%s': incompatible %s forward declaration and concrete kind %s\n", + sym_name, btf_kflag(t1) ? "union" : "struct", btf_kind_str(t2)); + } else { + if (btf_kflag(t2) && btf_is_union(t1)) + return true; + if (!btf_kflag(t2) && btf_is_struct(t1)) + return true; + pr_warn("global '%s': incompatible %s forward declaration and concrete kind %s\n", + sym_name, btf_kflag(t2) ? "union" : "struct", btf_kind_str(t1)); + } + return false; + } + + if (btf_kind(t1) != btf_kind(t2)) { + pr_warn("global '%s': incompatible BTF kinds %s and %s\n", + sym_name, btf_kind_str(t1), btf_kind_str(t2)); + return false; + } + + switch (btf_kind(t1)) { + case BTF_KIND_STRUCT: + case BTF_KIND_UNION: + case BTF_KIND_ENUM: + case BTF_KIND_FWD: + case BTF_KIND_FUNC: + case BTF_KIND_VAR: + n1 = btf__str_by_offset(btf1, t1->name_off); + n2 = btf__str_by_offset(btf2, t2->name_off); + if (strcmp(n1, n2) != 0) { + pr_warn("global '%s': incompatible %s names '%s' and '%s'\n", + sym_name, btf_kind_str(t1), n1, n2); + return false; + } + break; + default: + break; + } + + switch (btf_kind(t1)) { + case BTF_KIND_UNKN: /* void */ + case BTF_KIND_FWD: + return true; + case BTF_KIND_INT: + case BTF_KIND_FLOAT: + case BTF_KIND_ENUM: + /* ignore encoding for int and enum values for enum */ + if (t1->size != t2->size) { + pr_warn("global '%s': incompatible %s '%s' size %u and %u\n", + sym_name, btf_kind_str(t1), n1, t1->size, t2->size); + return false; + } + return true; + case BTF_KIND_PTR: + /* just validate overall shape of the referenced type, so no + * contents comparison for struct/union, and allowd fwd vs + * struct/union + */ + exact = false; + id1 = t1->type; + id2 = t2->type; + goto recur; + case BTF_KIND_ARRAY: + /* ignore index type and array size */ + id1 = btf_array(t1)->type; + id2 = btf_array(t2)->type; + goto recur; + case BTF_KIND_FUNC: + /* extern and global linkages are compatible */ + is_static1 = btf_func_linkage(t1) == BTF_FUNC_STATIC; + is_static2 = btf_func_linkage(t2) == BTF_FUNC_STATIC; + if (is_static1 != is_static2) { + pr_warn("global '%s': incompatible func '%s' linkage\n", sym_name, n1); + return false; + } + + id1 = t1->type; + id2 = t2->type; + goto recur; + case BTF_KIND_VAR: + /* extern and global linkages are compatible */ + is_static1 = btf_var(t1)->linkage == BTF_VAR_STATIC; + is_static2 = btf_var(t2)->linkage == BTF_VAR_STATIC; + if (is_static1 != is_static2) { + pr_warn("global '%s': incompatible var '%s' linkage\n", sym_name, n1); + return false; + } + + id1 = t1->type; + id2 = t2->type; + goto recur; + case BTF_KIND_STRUCT: + case BTF_KIND_UNION: { + const struct btf_member *m1, *m2; + + if (!exact) + return true; + + if (btf_vlen(t1) != btf_vlen(t2)) { + pr_warn("global '%s': incompatible number of %s fields %u and %u\n", + sym_name, btf_kind_str(t1), btf_vlen(t1), btf_vlen(t2)); + return false; + } + + n = btf_vlen(t1); + m1 = btf_members(t1); + m2 = btf_members(t2); + for (i = 0; i < n; i++, m1++, m2++) { + n1 = btf__str_by_offset(btf1, m1->name_off); + n2 = btf__str_by_offset(btf2, m2->name_off); + if (strcmp(n1, n2) != 0) { + pr_warn("global '%s': incompatible field #%d names '%s' and '%s'\n", + sym_name, i, n1, n2); + return false; + } + if (m1->offset != m2->offset) { + pr_warn("global '%s': incompatible field #%d ('%s') offsets\n", + sym_name, i, n1); + return false; + } + if (!glob_sym_btf_matches(sym_name, exact, btf1, m1->type, btf2, m2->type)) + return false; + } + + return true; + } + case BTF_KIND_FUNC_PROTO: { + const struct btf_param *m1, *m2; + + if (btf_vlen(t1) != btf_vlen(t2)) { + pr_warn("global '%s': incompatible number of %s params %u and %u\n", + sym_name, btf_kind_str(t1), btf_vlen(t1), btf_vlen(t2)); + return false; + } + + n = btf_vlen(t1); + m1 = btf_params(t1); + m2 = btf_params(t2); + for (i = 0; i < n; i++, m1++, m2++) { + /* ignore func arg names */ + if (!glob_sym_btf_matches(sym_name, exact, btf1, m1->type, btf2, m2->type)) + return false; + } + + /* now check return type as well */ + id1 = t1->type; + id2 = t2->type; + goto recur; + } + + case BTF_KIND_TYPEDEF: + case BTF_KIND_VOLATILE: + case BTF_KIND_CONST: + case BTF_KIND_RESTRICT: + case BTF_KIND_DATASEC: + default: + pr_warn("global '%s': unsupported BTF kind %s\n", + sym_name, btf_kind_str(t1)); + return false; + } +} + +static bool glob_syms_match(const char *sym_name, + struct bpf_linker *linker, struct glob_sym *glob_sym, + struct src_obj *obj, Elf64_Sym *sym, size_t sym_idx, int btf_id) +{ + const struct btf_type *src_t; + + /* if we are dealing with externs, BTF types describing both global + * and extern VARs/FUNCs should be completely present in all files + */ + if (!glob_sym->btf_id || !btf_id) { + pr_warn("BTF info is missing for global symbol '%s'\n", sym_name); + return false; + } + + src_t = btf__type_by_id(obj->btf, btf_id); + if (!btf_is_var(src_t) && !btf_is_func(src_t)) { + pr_warn("only extern variables and functions are supported, but got '%s' for '%s'\n", + btf_kind_str(src_t), sym_name); + return false; + } + + if (!glob_sym_btf_matches(sym_name, true /*exact*/, + linker->btf, glob_sym->btf_id, obj->btf, btf_id)) + return false; + + return true; +} + +static bool btf_is_non_static(const struct btf_type *t) +{ + return (btf_is_var(t) && btf_var(t)->linkage != BTF_VAR_STATIC) + || (btf_is_func(t) && btf_func_linkage(t) != BTF_FUNC_STATIC); +} + +static int find_glob_sym_btf(struct src_obj *obj, Elf64_Sym *sym, const char *sym_name, + int *out_btf_sec_id, int *out_btf_id) +{ + int i, j, n = btf__get_nr_types(obj->btf), m, btf_id = 0; + const struct btf_type *t; + const struct btf_var_secinfo *vi; + const char *name; + + for (i = 1; i <= n; i++) { + t = btf__type_by_id(obj->btf, i); + + /* some global and extern FUNCs and VARs might not be associated with any + * DATASEC, so try to detect them in the same pass + */ + if (btf_is_non_static(t)) { + name = btf__str_by_offset(obj->btf, t->name_off); + if (strcmp(name, sym_name) != 0) continue; - dst_sec = &linker->secs[src_sec->dst_id]; - /* allow only one STT_SECTION symbol per section */ - if (ELF64_ST_TYPE(sym->st_info) == STT_SECTION && dst_sec->sec_sym_idx) { - obj->sym_map[i] = dst_sec->sec_sym_idx; + /* remember and still try to find DATASEC */ + btf_id = i; + continue; + } + + if (!btf_is_datasec(t)) + continue; + + vi = btf_var_secinfos(t); + for (j = 0, m = btf_vlen(t); j < m; j++, vi++) { + t = btf__type_by_id(obj->btf, vi->type); + name = btf__str_by_offset(obj->btf, t->name_off); + + if (strcmp(name, sym_name) != 0) + continue; + if (btf_is_var(t) && btf_var(t)->linkage == BTF_VAR_STATIC) continue; + if (btf_is_func(t) && btf_func_linkage(t) == BTF_FUNC_STATIC) + continue; + + if (btf_id && btf_id != vi->type) { + pr_warn("global/extern '%s' BTF is ambiguous: both types #%d and #%u match\n", + sym_name, btf_id, vi->type); + return -EINVAL; } + + *out_btf_sec_id = i; + *out_btf_id = vi->type; + + return 0; } + } - name_off = strset__add_str(linker->strtab_strs, sym_name); - if (name_off < 0) - return name_off; + /* free-floating extern or global FUNC */ + if (btf_id) { + *out_btf_sec_id = 0; + *out_btf_id = btf_id; + return 0; + } - dst_sym = add_new_sym(linker, &dst_sym_idx); - if (!dst_sym) - return -ENOMEM; + pr_warn("failed to find BTF info for global/extern symbol '%s'\n", sym_name); + return -ENOENT; +} - dst_sym->st_name = name_off; - dst_sym->st_info = sym->st_info; - dst_sym->st_other = sym->st_other; - dst_sym->st_shndx = src_sec ? dst_sec->sec_idx : sym->st_shndx; - dst_sym->st_value = (src_sec ? src_sec->dst_off : 0) + sym->st_value; - dst_sym->st_size = sym->st_size; +static struct src_sec *find_src_sec_by_name(struct src_obj *obj, const char *sec_name) +{ + struct src_sec *sec; + int i; - obj->sym_map[i] = dst_sym_idx; + for (i = 1; i < obj->sec_cnt; i++) { + sec = &obj->secs[i]; - if (ELF64_ST_TYPE(sym->st_info) == STT_SECTION && dst_sym) { - dst_sec->sec_sym_idx = dst_sym_idx; - dst_sym->st_value = 0; + if (strcmp(sec->sec_name, sec_name) == 0) + return sec; + } + + return NULL; +} + +static int complete_extern_btf_info(struct btf *dst_btf, int dst_id, + struct btf *src_btf, int src_id) +{ + struct btf_type *dst_t = btf_type_by_id(dst_btf, dst_id); + struct btf_type *src_t = btf_type_by_id(src_btf, src_id); + struct btf_param *src_p, *dst_p; + const char *s; + int i, n, off; + + /* We already made sure that source and destination types (FUNC or + * VAR) match in terms of types and argument names. + */ + if (btf_is_var(dst_t)) { + btf_var(dst_t)->linkage = BTF_VAR_GLOBAL_ALLOCATED; + return 0; + } + + dst_t->info = btf_type_info(BTF_KIND_FUNC, BTF_FUNC_GLOBAL, 0); + + /* now onto FUNC_PROTO types */ + src_t = btf_type_by_id(src_btf, src_t->type); + dst_t = btf_type_by_id(dst_btf, dst_t->type); + + /* Fill in all the argument names, which for extern FUNCs are missing. + * We'll end up with two copies of FUNCs/VARs for externs, but that + * will be taken care of by BTF dedup at the very end. + * It might be that BTF types for extern in one file has less/more BTF + * information (e.g., FWD instead of full STRUCT/UNION information), + * but that should be (in most cases, subject to BTF dedup rules) + * handled and resolved by BTF dedup algorithm as well, so we won't + * worry about it. Our only job is to make sure that argument names + * are populated on both sides, otherwise BTF dedup will pedantically + * consider them different. + */ + src_p = btf_params(src_t); + dst_p = btf_params(dst_t); + for (i = 0, n = btf_vlen(dst_t); i < n; i++, src_p++, dst_p++) { + if (!src_p->name_off) + continue; + + /* src_btf has more complete info, so add name to dst_btf */ + s = btf__str_by_offset(src_btf, src_p->name_off); + off = btf__add_str(dst_btf, s); + if (off < 0) + return off; + dst_p->name_off = off; + } + return 0; +} + +static void sym_update_bind(Elf64_Sym *sym, int sym_bind) +{ + sym->st_info = ELF64_ST_INFO(sym_bind, ELF64_ST_TYPE(sym->st_info)); +} + +static void sym_update_type(Elf64_Sym *sym, int sym_type) +{ + sym->st_info = ELF64_ST_INFO(ELF64_ST_BIND(sym->st_info), sym_type); +} + +static void sym_update_visibility(Elf64_Sym *sym, int sym_vis) +{ + /* libelf doesn't provide setters for ST_VISIBILITY, + * but it is stored in the lower 2 bits of st_other + */ + sym->st_other &= 0x03; + sym->st_other |= sym_vis; +} + +static int linker_append_elf_sym(struct bpf_linker *linker, struct src_obj *obj, + Elf64_Sym *sym, const char *sym_name, int src_sym_idx) +{ + struct src_sec *src_sec = NULL; + struct dst_sec *dst_sec = NULL; + struct glob_sym *glob_sym = NULL; + int name_off, sym_type, sym_bind, sym_vis, err; + int btf_sec_id = 0, btf_id = 0; + size_t dst_sym_idx; + Elf64_Sym *dst_sym; + bool sym_is_extern; + + sym_type = ELF64_ST_TYPE(sym->st_info); + sym_bind = ELF64_ST_BIND(sym->st_info); + sym_vis = ELF64_ST_VISIBILITY(sym->st_other); + sym_is_extern = sym->st_shndx == SHN_UNDEF; + + if (sym_is_extern) { + if (!obj->btf) { + pr_warn("externs without BTF info are not supported\n"); + return -ENOTSUP; + } + } else if (sym->st_shndx < SHN_LORESERVE) { + src_sec = &obj->secs[sym->st_shndx]; + if (src_sec->skipped) + return 0; + dst_sec = &linker->secs[src_sec->dst_id]; + + /* allow only one STT_SECTION symbol per section */ + if (sym_type == STT_SECTION && dst_sec->sec_sym_idx) { + obj->sym_map[src_sym_idx] = dst_sec->sec_sym_idx; + return 0; + } + } + + if (sym_bind == STB_LOCAL) + goto add_sym; + + /* find matching BTF info */ + err = find_glob_sym_btf(obj, sym, sym_name, &btf_sec_id, &btf_id); + if (err) + return err; + + if (sym_is_extern && btf_sec_id) { + const char *sec_name = NULL; + const struct btf_type *t; + + t = btf__type_by_id(obj->btf, btf_sec_id); + sec_name = btf__str_by_offset(obj->btf, t->name_off); + + /* Clang puts unannotated extern vars into + * '.extern' BTF DATASEC. Treat them the same + * as unannotated extern funcs (which are + * currently not put into any DATASECs). + * Those don't have associated src_sec/dst_sec. + */ + if (strcmp(sec_name, BTF_EXTERN_SEC) != 0) { + src_sec = find_src_sec_by_name(obj, sec_name); + if (!src_sec) { + pr_warn("failed to find matching ELF sec '%s'\n", sec_name); + return -ENOENT; + } + dst_sec = &linker->secs[src_sec->dst_id]; + } + } + + glob_sym = find_glob_sym(linker, sym_name); + if (glob_sym) { + /* Preventively resolve to existing symbol. This is + * needed for further relocation symbol remapping in + * the next step of linking. + */ + obj->sym_map[src_sym_idx] = glob_sym->sym_idx; + + /* If both symbols are non-externs, at least one of + * them has to be STB_WEAK, otherwise they are in + * a conflict with each other. + */ + if (!sym_is_extern && !glob_sym->is_extern + && !glob_sym->is_weak && sym_bind != STB_WEAK) { + pr_warn("conflicting non-weak symbol #%d (%s) definition in '%s'\n", + src_sym_idx, sym_name, obj->filename); + return -EINVAL; } + if (!glob_syms_match(sym_name, linker, glob_sym, obj, sym, src_sym_idx, btf_id)) + return -EINVAL; + + dst_sym = get_sym_by_idx(linker, glob_sym->sym_idx); + + /* If new symbol is strong, then force dst_sym to be strong as + * well; this way a mix of weak and non-weak extern + * definitions will end up being strong. + */ + if (sym_bind == STB_GLOBAL) { + /* We still need to preserve type (NOTYPE or + * OBJECT/FUNC, depending on whether the symbol is + * extern or not) + */ + sym_update_bind(dst_sym, STB_GLOBAL); + glob_sym->is_weak = false; + } + + /* Non-default visibility is "contaminating", with stricter + * visibility overwriting more permissive ones, even if more + * permissive visibility comes from just an extern definition + */ + if (sym_vis > ELF64_ST_VISIBILITY(dst_sym->st_other)) + sym_update_visibility(dst_sym, sym_vis); + + /* If the new symbol is extern, then regardless if + * existing symbol is extern or resolved global, just + * keep the existing one untouched. + */ + if (sym_is_extern) + return 0; + + /* If existing symbol is a strong resolved symbol, bail out, + * because we lost resolution battle have nothing to + * contribute. We already checked abover that there is no + * strong-strong conflict. We also already tightened binding + * and visibility, so nothing else to contribute at that point. + */ + if (!glob_sym->is_extern && sym_bind == STB_WEAK) + return 0; + + /* At this point, new symbol is strong non-extern, + * so overwrite glob_sym with new symbol information. + * Preserve binding and visibility. + */ + sym_update_type(dst_sym, sym_type); + dst_sym->st_shndx = dst_sec->sec_idx; + dst_sym->st_value = src_sec->dst_off + sym->st_value; + dst_sym->st_size = sym->st_size; + + /* see comment below about dst_sec->id vs dst_sec->sec_idx */ + glob_sym->sec_id = dst_sec->id; + glob_sym->is_extern = false; + /* never relax strong to weak binding */ + if (sym_bind == STB_GLOBAL) + glob_sym->is_weak = false; + + if (complete_extern_btf_info(linker->btf, glob_sym->btf_id, + obj->btf, btf_id)) + return -EINVAL; + + /* request updating VAR's/FUNC's underlying BTF type when appending BTF type */ + glob_sym->underlying_btf_id = 0; + + obj->sym_map[src_sym_idx] = glob_sym->sym_idx; + return 0; + } + +add_sym: + name_off = strset__add_str(linker->strtab_strs, sym_name); + if (name_off < 0) + return name_off; + + dst_sym = add_new_sym(linker, &dst_sym_idx); + if (!dst_sym) + return -ENOMEM; + + dst_sym->st_name = name_off; + dst_sym->st_info = sym->st_info; + dst_sym->st_other = sym->st_other; + dst_sym->st_shndx = dst_sec ? dst_sec->sec_idx : sym->st_shndx; + dst_sym->st_value = (src_sec ? src_sec->dst_off : 0) + sym->st_value; + dst_sym->st_size = sym->st_size; + + obj->sym_map[src_sym_idx] = dst_sym_idx; + + if (sym_type == STT_SECTION && dst_sym) { + dst_sec->sec_sym_idx = dst_sym_idx; + dst_sym->st_value = 0; + } + + if (sym_bind != STB_LOCAL) { + glob_sym = add_glob_sym(linker); + if (!glob_sym) + return -ENOMEM; + + glob_sym->sym_idx = dst_sym_idx; + /* we use dst_sec->id (and not dst_sec->sec_idx), because + * ephemeral sections (.kconfig, .ksyms, etc) don't have + * sec_idx (as they don't have corresponding ELF section), but + * still have id. .extern doesn't have even ephemeral section + * associated with it, so dst_sec->id == dst_sec->sec_idx == 0. + */ + glob_sym->sec_id = dst_sec ? dst_sec->id : 0; + glob_sym->name_off = name_off; + /* we will fill btf_id in during BTF merging step */ + glob_sym->btf_id = 0; + glob_sym->is_extern = sym_is_extern; + glob_sym->is_weak = sym_bind == STB_WEAK; } return 0; @@ -1256,7 +1887,7 @@ static int linker_append_elf_relos(struct bpf_linker *linker, struct src_obj *ob dst_sec->shdr->sh_info = dst_linked_sec->sec_idx; src_sec->dst_id = dst_sec->id; - err = extend_sec(dst_sec, src_sec); + err = extend_sec(linker, dst_sec, src_sec); if (err) return err; @@ -1309,21 +1940,6 @@ static int linker_append_elf_relos(struct bpf_linker *linker, struct src_obj *ob return 0; } -static struct src_sec *find_src_sec_by_name(struct src_obj *obj, const char *sec_name) -{ - struct src_sec *sec; - int i; - - for (i = 1; i < obj->sec_cnt; i++) { - sec = &obj->secs[i]; - - if (strcmp(sec->sec_name, sec_name) == 0) - return sec; - } - - return NULL; -} - static Elf64_Sym *find_sym_by_name(struct src_obj *obj, size_t sec_idx, int sym_type, const char *sym_name) { @@ -1378,12 +1994,32 @@ static int linker_fixup_btf(struct src_obj *obj) t->size = sec->shdr->sh_size; } else { /* BTF can have some sections that are not represented - * in ELF, e.g., .kconfig and .ksyms, which are used - * for special extern variables. Here we'll - * pre-create "section shells" for them to be able to - * keep track of extra per-section metadata later - * (e.g., BTF variables). + * in ELF, e.g., .kconfig, .ksyms, .extern, which are used + * for special extern variables. + * + * For all but one such special (ephemeral) + * sections, we pre-create "section shells" to be able + * to keep track of extra per-section metadata later + * (e.g., those BTF extern variables). + * + * .extern is even more special, though, because it + * contains extern variables that need to be resolved + * by static linker, not libbpf and kernel. When such + * externs are resolved, we are going to remove them + * from .extern BTF section and might end up not + * needing it at all. Each resolved extern should have + * matching non-extern VAR/FUNC in other sections. + * + * We do support leaving some of the externs + * unresolved, though, to support cases of building + * libraries, which will later be linked against final + * BPF applications. So if at finalization we still + * see unresolved externs, we'll create .extern + * section on our own. */ + if (strcmp(sec_name, BTF_EXTERN_SEC) == 0) + continue; + sec = add_src_sec(obj, sec_name); if (!sec) return -ENOMEM; @@ -1442,6 +2078,7 @@ static int linker_append_btf(struct bpf_linker *linker, struct src_obj *obj) { const struct btf_type *t; int i, j, n, start_id, id; + const char *name; if (!obj->btf) return 0; @@ -1454,12 +2091,40 @@ static int linker_append_btf(struct bpf_linker *linker, struct src_obj *obj) return -ENOMEM; for (i = 1; i <= n; i++) { + struct glob_sym *glob_sym = NULL; + t = btf__type_by_id(obj->btf, i); /* DATASECs are handled specially below */ if (btf_kind(t) == BTF_KIND_DATASEC) continue; + if (btf_is_non_static(t)) { + /* there should be glob_sym already */ + name = btf__str_by_offset(obj->btf, t->name_off); + glob_sym = find_glob_sym(linker, name); + + /* VARs without corresponding glob_sym are those that + * belong to skipped/deduplicated sections (i.e., + * license and version), so just skip them + */ + if (!glob_sym) + continue; + + if (glob_sym->underlying_btf_id == 0) + glob_sym->underlying_btf_id = -t->type; + + /* globals from previous object files that match our + * VAR/FUNC already have a corresponding associated + * BTF type, so just make sure to use it + */ + if (glob_sym->btf_id) { + /* reuse existing BTF type for global var/func */ + obj->btf_type_map[i] = glob_sym->btf_id; + continue; + } + } + id = btf__add_type(linker->btf, obj->btf, t); if (id < 0) { pr_warn("failed to append BTF type #%d from file '%s'\n", i, obj->filename); @@ -1467,6 +2132,12 @@ static int linker_append_btf(struct bpf_linker *linker, struct src_obj *obj) } obj->btf_type_map[i] = id; + + /* record just appended BTF type for var/func */ + if (glob_sym) { + glob_sym->btf_id = id; + glob_sym->underlying_btf_id = -t->type; + } } /* remap all the types except DATASECs */ @@ -1478,6 +2149,22 @@ static int linker_append_btf(struct bpf_linker *linker, struct src_obj *obj) return -EINVAL; } + /* Rewrite VAR/FUNC underlying types (i.e., FUNC's FUNC_PROTO and VAR's + * actual type), if necessary + */ + for (i = 0; i < linker->glob_sym_cnt; i++) { + struct glob_sym *glob_sym = &linker->glob_syms[i]; + struct btf_type *glob_t; + + if (glob_sym->underlying_btf_id >= 0) + continue; + + glob_sym->underlying_btf_id = obj->btf_type_map[-glob_sym->underlying_btf_id]; + + glob_t = btf_type_by_id(linker->btf, glob_sym->btf_id); + glob_t->type = glob_sym->underlying_btf_id; + } + /* append DATASEC info */ for (i = 1; i < obj->sec_cnt; i++) { struct src_sec *src_sec; @@ -1505,6 +2192,42 @@ static int linker_append_btf(struct bpf_linker *linker, struct src_obj *obj) n = btf_vlen(t); for (j = 0; j < n; j++, src_var++) { void *sec_vars = dst_sec->sec_vars; + int new_id = obj->btf_type_map[src_var->type]; + struct glob_sym *glob_sym = NULL; + + t = btf_type_by_id(linker->btf, new_id); + if (btf_is_non_static(t)) { + name = btf__str_by_offset(linker->btf, t->name_off); + glob_sym = find_glob_sym(linker, name); + if (glob_sym->sec_id != dst_sec->id) { + pr_warn("global '%s': section mismatch %d vs %d\n", + name, glob_sym->sec_id, dst_sec->id); + return -EINVAL; + } + } + + /* If there is already a member (VAR or FUNC) mapped + * to the same type, don't add a duplicate entry. + * This will happen when multiple object files define + * the same extern VARs/FUNCs. + */ + if (glob_sym && glob_sym->var_idx >= 0) { + __s64 sz; + + dst_var = &dst_sec->sec_vars[glob_sym->var_idx]; + /* Because underlying BTF type might have + * changed, so might its size have changed, so + * re-calculate and update it in sec_var. + */ + sz = btf__resolve_size(linker->btf, glob_sym->underlying_btf_id); + if (sz < 0) { + pr_warn("global '%s': failed to resolve size of underlying type: %d\n", + name, (int)sz); + return -EINVAL; + } + dst_var->size = sz; + continue; + } sec_vars = libbpf_reallocarray(sec_vars, dst_sec->sec_var_cnt + 1, @@ -1519,6 +2242,9 @@ static int linker_append_btf(struct bpf_linker *linker, struct src_obj *obj) dst_var->type = obj->btf_type_map[src_var->type]; dst_var->size = src_var->size; dst_var->offset = src_sec->dst_off + src_var->offset; + + if (glob_sym) + glob_sym->var_idx = dst_sec->sec_var_cnt - 1; } } From patchwork Fri Apr 16 20:23:59 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrii Nakryiko X-Patchwork-Id: 12208735 X-Patchwork-Delegate: bpf@iogearbox.net 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 68E06C433ED for ; Fri, 16 Apr 2021 20:24:52 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4FDFC6124B for ; Fri, 16 Apr 2021 20:24:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343676AbhDPUZQ convert rfc822-to-8bit (ORCPT ); Fri, 16 Apr 2021 16:25:16 -0400 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:26058 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343689AbhDPUZH (ORCPT ); Fri, 16 Apr 2021 16:25:07 -0400 Received: from pps.filterd (m0044010.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.43/8.16.0.43) with SMTP id 13GKLVKO021279 for ; Fri, 16 Apr 2021 13:24:42 -0700 Received: from maileast.thefacebook.com ([163.114.130.16]) by mx0a-00082601.pphosted.com with ESMTP id 37yb9y2drc-7 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Fri, 16 Apr 2021 13:24:42 -0700 Received: from intmgw001.05.ash7.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 15.1.2176.2; Fri, 16 Apr 2021 13:24:30 -0700 Received: by devbig012.ftw2.facebook.com (Postfix, from userid 137359) id 9F2F62ED4EE0; Fri, 16 Apr 2021 13:24:29 -0700 (PDT) From: Andrii Nakryiko To: , , , CC: , Subject: [PATCH v2 bpf-next 12/17] libbpf: support extern resolution for BTF-defined maps in .maps section Date: Fri, 16 Apr 2021 13:23:59 -0700 Message-ID: <20210416202404.3443623-13-andrii@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210416202404.3443623-1-andrii@kernel.org> References: <20210416202404.3443623-1-andrii@kernel.org> MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-ORIG-GUID: Ttn5nCBxCOAWc6NftLdMKI84U9-pVwax X-Proofpoint-GUID: Ttn5nCBxCOAWc6NftLdMKI84U9-pVwax X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.391,18.0.761 definitions=2021-04-16_09:2021-04-16,2021-04-16 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 malwarescore=0 spamscore=0 priorityscore=1501 phishscore=0 adultscore=0 lowpriorityscore=0 bulkscore=0 mlxscore=0 suspectscore=0 impostorscore=0 mlxlogscore=999 clxscore=1015 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2104060000 definitions=main-2104160143 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net Add extra logic to handle map externs (only BTF-defined maps are supported for linking). Re-use the map parsing logic used during bpf_object__open(). Map externs are currently restricted to always match complete map definition. So all the specified attributes will be compared (down to pining, map_flags, numa_node, etc). In the future this restriction might be relaxed with no backwards compatibility issues. If any attribute is mismatched between extern and actual map definition, linker will report an error, pointing out which one mismatches. The original intent was to allow for extern to specify attributes that matters (to user) to enforce. E.g., if you specify just key information and omit value, then any value fits. Similarly, it should have been possible to enforce map_flags, pinning, and any other possible map attribute. Unfortunately, that means that multiple externs can be only partially overlapping with each other, which means linker would need to combine their type definitions to end up with the most restrictive and fullest map definition. This requires an extra amount of BTF manipulation which at this time was deemed unnecessary and would require further extending generic BTF writer APIs. So that is left for future follow ups, if there will be demand for that. But the idea seems intresting and useful, so I want to document it here. Weak definitions are also supported, but are pretty strict as well, just like externs: all weak map definitions have to match exactly. In the follow up patches this most probably will be relaxed, with __weak map definitions being able to differ between each other (with non-weak definition always winning, of course). Signed-off-by: Andrii Nakryiko Acked-by: Yonghong Song --- tools/lib/bpf/linker.c | 132 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 132 insertions(+) diff --git a/tools/lib/bpf/linker.c b/tools/lib/bpf/linker.c index 67d2d06e3cb6..84d444427b65 100644 --- a/tools/lib/bpf/linker.c +++ b/tools/lib/bpf/linker.c @@ -1463,6 +1463,134 @@ static bool glob_sym_btf_matches(const char *sym_name, bool exact, } } +static bool map_defs_match(const char *sym_name, + const struct btf *main_btf, + const struct btf_map_def *main_def, + const struct btf_map_def *main_inner_def, + const struct btf *extra_btf, + const struct btf_map_def *extra_def, + const struct btf_map_def *extra_inner_def) +{ + const char *reason; + + if (main_def->map_type != extra_def->map_type) { + reason = "type"; + goto mismatch; + } + + /* check key type/size match */ + if (main_def->key_size != extra_def->key_size) { + reason = "key_size"; + goto mismatch; + } + if (!!main_def->key_type_id != !!extra_def->key_type_id) { + reason = "key type"; + goto mismatch; + } + if ((main_def->parts & MAP_DEF_KEY_TYPE) + && !glob_sym_btf_matches(sym_name, true /*exact*/, + main_btf, main_def->key_type_id, + extra_btf, extra_def->key_type_id)) { + reason = "key type"; + goto mismatch; + } + + /* validate value type/size match */ + if (main_def->value_size != extra_def->value_size) { + reason = "value_size"; + goto mismatch; + } + if (!!main_def->value_type_id != !!extra_def->value_type_id) { + reason = "value type"; + goto mismatch; + } + if ((main_def->parts & MAP_DEF_VALUE_TYPE) + && !glob_sym_btf_matches(sym_name, true /*exact*/, + main_btf, main_def->value_type_id, + extra_btf, extra_def->value_type_id)) { + reason = "key type"; + goto mismatch; + } + + if (main_def->max_entries != extra_def->max_entries) { + reason = "max_entries"; + goto mismatch; + } + if (main_def->map_flags != extra_def->map_flags) { + reason = "map_flags"; + goto mismatch; + } + if (main_def->numa_node != extra_def->numa_node) { + reason = "numa_node"; + goto mismatch; + } + if (main_def->pinning != extra_def->pinning) { + reason = "pinning"; + goto mismatch; + } + + if ((main_def->parts & MAP_DEF_INNER_MAP) != (extra_def->parts & MAP_DEF_INNER_MAP)) { + reason = "inner map"; + goto mismatch; + } + + if (main_def->parts & MAP_DEF_INNER_MAP) { + char inner_map_name[128]; + + snprintf(inner_map_name, sizeof(inner_map_name), "%s.inner", sym_name); + + return map_defs_match(inner_map_name, + main_btf, main_inner_def, NULL, + extra_btf, extra_inner_def, NULL); + } + + return true; + +mismatch: + pr_warn("global '%s': map %s mismatch\n", sym_name, reason); + return false; +} + +static bool glob_map_defs_match(const char *sym_name, + struct bpf_linker *linker, struct glob_sym *glob_sym, + struct src_obj *obj, Elf64_Sym *sym, int btf_id) +{ + struct btf_map_def dst_def = {}, dst_inner_def = {}; + struct btf_map_def src_def = {}, src_inner_def = {}; + const struct btf_type *t; + int err; + + t = btf__type_by_id(obj->btf, btf_id); + if (!btf_is_var(t)) { + pr_warn("global '%s': invalid map definition type [%d]\n", sym_name, btf_id); + return false; + } + t = skip_mods_and_typedefs(obj->btf, t->type, NULL); + + err = parse_btf_map_def(sym_name, obj->btf, t, true /*strict*/, &src_def, &src_inner_def); + if (err) { + pr_warn("global '%s': invalid map definition\n", sym_name); + return false; + } + + /* re-parse existing map definition */ + t = btf__type_by_id(linker->btf, glob_sym->btf_id); + t = skip_mods_and_typedefs(linker->btf, t->type, NULL); + err = parse_btf_map_def(sym_name, linker->btf, t, true /*strict*/, &dst_def, &dst_inner_def); + if (err) { + /* this should not happen, because we already validated it */ + pr_warn("global '%s': invalid dst map definition\n", sym_name); + return false; + } + + /* Currently extern map definition has to be complete and match + * concrete map definition exactly. This restriction might be lifted + * in the future. + */ + return map_defs_match(sym_name, linker->btf, &dst_def, &dst_inner_def, + obj->btf, &src_def, &src_inner_def); +} + static bool glob_syms_match(const char *sym_name, struct bpf_linker *linker, struct glob_sym *glob_sym, struct src_obj *obj, Elf64_Sym *sym, size_t sym_idx, int btf_id) @@ -1484,6 +1612,10 @@ static bool glob_syms_match(const char *sym_name, return false; } + /* deal with .maps definitions specially */ + if (glob_sym->sec_id && strcmp(linker->secs[glob_sym->sec_id].sec_name, MAPS_ELF_SEC) == 0) + return glob_map_defs_match(sym_name, linker, glob_sym, obj, sym, btf_id); + if (!glob_sym_btf_matches(sym_name, true /*exact*/, linker->btf, glob_sym->btf_id, obj->btf, btf_id)) return false; From patchwork Fri Apr 16 20:24:00 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrii Nakryiko X-Patchwork-Id: 12208733 X-Patchwork-Delegate: bpf@iogearbox.net 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 079F6C43461 for ; Fri, 16 Apr 2021 20:24:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E095161166 for ; Fri, 16 Apr 2021 20:24:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343586AbhDPUZO convert rfc822-to-8bit (ORCPT ); Fri, 16 Apr 2021 16:25:14 -0400 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:15266 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343541AbhDPUZF (ORCPT ); Fri, 16 Apr 2021 16:25:05 -0400 Received: from pps.filterd (m0044012.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.43/8.16.0.43) with SMTP id 13GKKCG5021851 for ; Fri, 16 Apr 2021 13:24:40 -0700 Received: from mail.thefacebook.com ([163.114.132.120]) by mx0a-00082601.pphosted.com with ESMTP id 37yb5j2f9f-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Fri, 16 Apr 2021 13:24:40 -0700 Received: from intmgw001.37.frc1.facebook.com (2620:10d:c085:208::f) by mail.thefacebook.com (2620:10d:c085:21d::4) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Fri, 16 Apr 2021 13:24:40 -0700 Received: by devbig012.ftw2.facebook.com (Postfix, from userid 137359) id AA5242ED4EE0; Fri, 16 Apr 2021 13:24:31 -0700 (PDT) From: Andrii Nakryiko To: , , , CC: , Subject: [PATCH v2 bpf-next 13/17] selftests/bpf: use -O0 instead of -Og in selftests builds Date: Fri, 16 Apr 2021 13:24:00 -0700 Message-ID: <20210416202404.3443623-14-andrii@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210416202404.3443623-1-andrii@kernel.org> References: <20210416202404.3443623-1-andrii@kernel.org> MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-GUID: uJyRrMQ0hgwrkqzeRQ-2CxmxHTgq1-gl X-Proofpoint-ORIG-GUID: uJyRrMQ0hgwrkqzeRQ-2CxmxHTgq1-gl X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.391,18.0.761 definitions=2021-04-16_09:2021-04-16,2021-04-16 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 clxscore=1034 phishscore=0 priorityscore=1501 mlxlogscore=999 spamscore=0 bulkscore=0 lowpriorityscore=0 impostorscore=0 adultscore=0 suspectscore=0 mlxscore=0 malwarescore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2104060000 definitions=main-2104160143 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net While -Og is designed to work well with debugger, it's still inferior to -O0 in terms of debuggability experience. It will cause some variables to still be inlined, it will also prevent single-stepping some statements and otherwise interfere with debugging experience. So switch to -O0 which turns off any optimization and provides the best debugging experience. Signed-off-by: Andrii Nakryiko Acked-by: Yonghong Song --- tools/testing/selftests/bpf/Makefile | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-) diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile index c45ae13b88a0..4ff4dc3710cd 100644 --- a/tools/testing/selftests/bpf/Makefile +++ b/tools/testing/selftests/bpf/Makefile @@ -21,7 +21,7 @@ endif BPF_GCC ?= $(shell command -v bpf-gcc;) SAN_CFLAGS ?= -CFLAGS += -g -Og -rdynamic -Wall $(GENFLAGS) $(SAN_CFLAGS) \ +CFLAGS += -g -O0 -rdynamic -Wall $(GENFLAGS) $(SAN_CFLAGS) \ -I$(CURDIR) -I$(INCLUDE_DIR) -I$(GENDIR) -I$(LIBDIR) \ -I$(TOOLSINCDIR) -I$(APIDIR) -I$(OUTPUT) \ -Dbpf_prog_load=bpf_prog_test_load \ @@ -206,7 +206,7 @@ $(DEFAULT_BPFTOOL): $(wildcard $(BPFTOOLDIR)/*.[ch] $(BPFTOOLDIR)/Makefile) \ $(HOST_BPFOBJ) | $(HOST_BUILD_DIR)/bpftool $(Q)$(MAKE) $(submake_extras) -C $(BPFTOOLDIR) \ CC=$(HOSTCC) LD=$(HOSTLD) \ - EXTRA_CFLAGS='-g -Og' \ + EXTRA_CFLAGS='-g -O0' \ OUTPUT=$(HOST_BUILD_DIR)/bpftool/ \ prefix= DESTDIR=$(HOST_SCRATCH_DIR)/ install @@ -224,7 +224,7 @@ $(BPFOBJ): $(wildcard $(BPFDIR)/*.[ch] $(BPFDIR)/Makefile) \ ../../../include/uapi/linux/bpf.h \ | $(INCLUDE_DIR) $(BUILD_DIR)/libbpf $(Q)$(MAKE) $(submake_extras) -C $(BPFDIR) OUTPUT=$(BUILD_DIR)/libbpf/ \ - EXTRA_CFLAGS='-g -Og' \ + EXTRA_CFLAGS='-g -O0' \ DESTDIR=$(SCRATCH_DIR) prefix= all install_headers ifneq ($(BPFOBJ),$(HOST_BPFOBJ)) @@ -232,7 +232,7 @@ $(HOST_BPFOBJ): $(wildcard $(BPFDIR)/*.[ch] $(BPFDIR)/Makefile) \ ../../../include/uapi/linux/bpf.h \ | $(INCLUDE_DIR) $(HOST_BUILD_DIR)/libbpf $(Q)$(MAKE) $(submake_extras) -C $(BPFDIR) \ - EXTRA_CFLAGS='-g -Og' \ + EXTRA_CFLAGS='-g -O0' \ OUTPUT=$(HOST_BUILD_DIR)/libbpf/ CC=$(HOSTCC) LD=$(HOSTLD) \ DESTDIR=$(HOST_SCRATCH_DIR)/ prefix= all install_headers endif From patchwork Fri Apr 16 20:24:01 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrii Nakryiko X-Patchwork-Id: 12208729 X-Patchwork-Delegate: bpf@iogearbox.net 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=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 3B46FC433B4 for ; Fri, 16 Apr 2021 20:24:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 23AC86124B for ; Fri, 16 Apr 2021 20:24:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343636AbhDPUZF convert rfc822-to-8bit (ORCPT ); Fri, 16 Apr 2021 16:25:05 -0400 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:54316 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343531AbhDPUZA (ORCPT ); Fri, 16 Apr 2021 16:25:00 -0400 Received: from pps.filterd (m0109334.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.43/8.16.0.43) with SMTP id 13GKI72J002049 for ; Fri, 16 Apr 2021 13:24:35 -0700 Received: from mail.thefacebook.com ([163.114.132.120]) by mx0a-00082601.pphosted.com with ESMTP id 37ydj4sjf5-2 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Fri, 16 Apr 2021 13:24:35 -0700 Received: from intmgw002.25.frc3.facebook.com (2620:10d:c085:208::11) by mail.thefacebook.com (2620:10d:c085:21d::4) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Fri, 16 Apr 2021 13:24:34 -0700 Received: by devbig012.ftw2.facebook.com (Postfix, from userid 137359) id B79622ED4EE0; Fri, 16 Apr 2021 13:24:33 -0700 (PDT) From: Andrii Nakryiko To: , , , CC: , Subject: [PATCH v2 bpf-next 14/17] selftests/bpf: omit skeleton generation for multi-linked BPF object files Date: Fri, 16 Apr 2021 13:24:01 -0700 Message-ID: <20210416202404.3443623-15-andrii@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210416202404.3443623-1-andrii@kernel.org> References: <20210416202404.3443623-1-andrii@kernel.org> MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-GUID: AjHZGnN2Dfkjnt0GTMHRVuHYMRsyPB5M X-Proofpoint-ORIG-GUID: AjHZGnN2Dfkjnt0GTMHRVuHYMRsyPB5M X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.391,18.0.761 definitions=2021-04-16_09:2021-04-16,2021-04-16 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 clxscore=1015 suspectscore=0 phishscore=0 lowpriorityscore=0 impostorscore=0 bulkscore=0 spamscore=0 priorityscore=1501 malwarescore=0 mlxscore=0 adultscore=0 mlxlogscore=999 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2104060000 definitions=main-2104160143 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net Skip generating individual BPF skeletons for files that are supposed to be linked together to form the final BPF object file. Very often such files are "incomplete" BPF object files, which will fail libbpf bpf_object__open() step, if used individually, thus failing BPF skeleton generation. This is by design, so skip individual BPF skeletons and only validate them as part of their linked final BPF object file and skeleton. Signed-off-by: Andrii Nakryiko Acked-by: Yonghong Song --- tools/testing/selftests/bpf/Makefile | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile index 4ff4dc3710cd..666b462c1218 100644 --- a/tools/testing/selftests/bpf/Makefile +++ b/tools/testing/selftests/bpf/Makefile @@ -312,6 +312,8 @@ LINKED_SKELS := test_static_linked.skel.h test_static_linked.skel.h-deps := test_static_linked1.o test_static_linked2.o +LINKED_BPF_SRCS := $(patsubst %.o,%.c,$(foreach skel,$(LINKED_SKELS),$($(skel)-deps))) + # Set up extra TRUNNER_XXX "temporary" variables in the environment (relies on # $eval()) and pass control to DEFINE_TEST_RUNNER_RULES. # Parameters: @@ -330,7 +332,7 @@ TRUNNER_TESTS_HDR := $(TRUNNER_TESTS_DIR)/tests.h TRUNNER_BPF_SRCS := $$(notdir $$(wildcard $(TRUNNER_BPF_PROGS_DIR)/*.c)) TRUNNER_BPF_OBJS := $$(patsubst %.c,$$(TRUNNER_OUTPUT)/%.o, $$(TRUNNER_BPF_SRCS)) TRUNNER_BPF_SKELS := $$(patsubst %.c,$$(TRUNNER_OUTPUT)/%.skel.h, \ - $$(filter-out $(SKEL_BLACKLIST), \ + $$(filter-out $(SKEL_BLACKLIST) $(LINKED_BPF_SRCS),\ $$(TRUNNER_BPF_SRCS))) TRUNNER_BPF_SKELS_LINKED := $$(addprefix $$(TRUNNER_OUTPUT)/,$(LINKED_SKELS)) TEST_GEN_FILES += $$(TRUNNER_BPF_OBJS) From patchwork Fri Apr 16 20:24:02 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrii Nakryiko X-Patchwork-Id: 12208731 X-Patchwork-Delegate: bpf@iogearbox.net 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=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 3E2BDC433ED for ; Fri, 16 Apr 2021 20:24:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1550D613CD for ; Fri, 16 Apr 2021 20:24:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343560AbhDPUZN convert rfc822-to-8bit (ORCPT ); Fri, 16 Apr 2021 16:25:13 -0400 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:41294 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1343632AbhDPUZE (ORCPT ); Fri, 16 Apr 2021 16:25:04 -0400 Received: from pps.filterd (m0044010.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.0.43/8.16.0.43) with SMTP id 13GKMacs024601 for ; Fri, 16 Apr 2021 13:24:39 -0700 Received: from mail.thefacebook.com ([163.114.132.120]) by mx0a-00082601.pphosted.com with ESMTP id 37yb9y2drj-2 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Fri, 16 Apr 2021 13:24:39 -0700 Received: from intmgw002.25.frc3.facebook.com (2620:10d:c085:208::f) by mail.thefacebook.com (2620:10d:c085:21d::5) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Fri, 16 Apr 2021 13:24:39 -0700 Received: by devbig012.ftw2.facebook.com (Postfix, from userid 137359) id C03312ED4EE0; Fri, 16 Apr 2021 13:24:36 -0700 (PDT) From: Andrii Nakryiko To: , , , CC: , Subject: [PATCH v2 bpf-next 15/17] selftests/bpf: add function linking selftest Date: Fri, 16 Apr 2021 13:24:02 -0700 Message-ID: <20210416202404.3443623-16-andrii@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210416202404.3443623-1-andrii@kernel.org> References: <20210416202404.3443623-1-andrii@kernel.org> MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-ORIG-GUID: 1w7pdA6gzMoYlxFcGH9Z3FQ6NDvb_Pra X-Proofpoint-GUID: 1w7pdA6gzMoYlxFcGH9Z3FQ6NDvb_Pra X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.391,18.0.761 definitions=2021-04-16_09:2021-04-16,2021-04-16 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 malwarescore=0 spamscore=0 priorityscore=1501 phishscore=0 adultscore=0 lowpriorityscore=0 bulkscore=0 mlxscore=0 suspectscore=0 impostorscore=0 mlxlogscore=999 clxscore=1015 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2104060000 definitions=main-2104160143 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net Add selftest validating various aspects of statically linking functions: - no conflicts and correct resolution for name-conflicting static funcs; - correct resolution of extern functions; - correct handling of weak functions, both resolution itself and libbpf's handling of unused weak function that "lost" (it leaves gaps in code with no ELF symbols); - correct handling of hidden visibility to turn global function into "static" for the purpose of BPF verification. Signed-off-by: Andrii Nakryiko Acked-by: Yonghong Song --- tools/testing/selftests/bpf/Makefile | 3 +- .../selftests/bpf/prog_tests/linked_funcs.c | 42 +++++++++++ .../selftests/bpf/progs/linked_funcs1.c | 73 +++++++++++++++++++ .../selftests/bpf/progs/linked_funcs2.c | 73 +++++++++++++++++++ 4 files changed, 190 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/bpf/prog_tests/linked_funcs.c create mode 100644 tools/testing/selftests/bpf/progs/linked_funcs1.c create mode 100644 tools/testing/selftests/bpf/progs/linked_funcs2.c diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile index 666b462c1218..427ccfec1a6a 100644 --- a/tools/testing/selftests/bpf/Makefile +++ b/tools/testing/selftests/bpf/Makefile @@ -308,9 +308,10 @@ endef SKEL_BLACKLIST := btf__% test_pinning_invalid.c test_sk_assign.c -LINKED_SKELS := test_static_linked.skel.h +LINKED_SKELS := test_static_linked.skel.h linked_funcs.skel.h test_static_linked.skel.h-deps := test_static_linked1.o test_static_linked2.o +linked_funcs.skel.h-deps := linked_funcs1.o linked_funcs2.o LINKED_BPF_SRCS := $(patsubst %.o,%.c,$(foreach skel,$(LINKED_SKELS),$($(skel)-deps))) diff --git a/tools/testing/selftests/bpf/prog_tests/linked_funcs.c b/tools/testing/selftests/bpf/prog_tests/linked_funcs.c new file mode 100644 index 000000000000..03bf8ef131ce --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/linked_funcs.c @@ -0,0 +1,42 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2021 Facebook */ + +#include +#include +#include "linked_funcs.skel.h" + +void test_linked_funcs(void) +{ + int err; + struct linked_funcs *skel; + + skel = linked_funcs__open(); + if (!ASSERT_OK_PTR(skel, "skel_open")) + return; + + skel->rodata->my_tid = syscall(SYS_gettid); + skel->rodata->syscall_id = SYS_getpgid; + + err = linked_funcs__load(skel); + if (!ASSERT_OK(err, "skel_load")) + goto cleanup; + + err = linked_funcs__attach(skel); + if (!ASSERT_OK(err, "skel_attach")) + goto cleanup; + + /* trigger */ + syscall(SYS_getpgid); + + ASSERT_EQ(skel->bss->output_val1, 2000 + 2000, "output_val1"); + ASSERT_EQ(skel->bss->output_ctx1, SYS_getpgid, "output_ctx1"); + ASSERT_EQ(skel->bss->output_weak1, 42, "output_weak1"); + + ASSERT_EQ(skel->bss->output_val2, 2 * 1000 + 2 * (2 * 1000), "output_val2"); + ASSERT_EQ(skel->bss->output_ctx2, SYS_getpgid, "output_ctx2"); + /* output_weak2 should never be updated */ + ASSERT_EQ(skel->bss->output_weak2, 0, "output_weak2"); + +cleanup: + linked_funcs__destroy(skel); +} diff --git a/tools/testing/selftests/bpf/progs/linked_funcs1.c b/tools/testing/selftests/bpf/progs/linked_funcs1.c new file mode 100644 index 000000000000..cc621d4e4d82 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/linked_funcs1.c @@ -0,0 +1,73 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2021 Facebook */ + +#include "vmlinux.h" +#include +#include + +/* weak and shared between two files */ +const volatile int my_tid __weak = 0; +const volatile long syscall_id __weak = 0; + +int output_val1 = 0; +int output_ctx1 = 0; +int output_weak1 = 0; + +/* same "subprog" name in all files, but it's ok because they all are static */ +static __noinline int subprog(int x) +{ + /* but different formula */ + return x * 1; +} + +/* Global functions can't be void */ +int set_output_val1(int x) +{ + output_val1 = x + subprog(x); + return x; +} + +/* This function can't be verified as global, as it assumes raw_tp/sys_enter + * context and accesses syscall id (second argument). So we mark it as + * __hidden, so that libbpf will mark it as static in the final object file, + * right before verifying it in the kernel. + * + * But we don't mark it as __hidden here, rather at extern site. __hidden is + * "contaminating" visibility, so it will get propagated from either extern or + * actual definition (including from the losing __weak definition). + */ +void set_output_ctx1(__u64 *ctx) +{ + output_ctx1 = ctx[1]; /* long id, same as in BPF_PROG below */ +} + +/* this weak instance should win because it's the first one */ +__weak int set_output_weak(int x) +{ + output_weak1 = x; + return x; +} + +extern int set_output_val2(int x); + +/* here we'll force set_output_ctx2() to be __hidden in the final obj file */ +__hidden extern void set_output_ctx2(__u64 *ctx); + +SEC("raw_tp/sys_enter") +int BPF_PROG(handler1, struct pt_regs *regs, long id) +{ + if (my_tid != (u32)bpf_get_current_pid_tgid() || id != syscall_id) + return 0; + + set_output_val2(1000); + set_output_ctx2(ctx); /* ctx definition is hidden in BPF_PROG macro */ + + /* keep input value the same across both files to avoid dependency on + * handler call order; differentiate by output_weak1 vs output_weak2. + */ + set_output_weak(42); + + return 0; +} + +char LICENSE[] SEC("license") = "GPL"; diff --git a/tools/testing/selftests/bpf/progs/linked_funcs2.c b/tools/testing/selftests/bpf/progs/linked_funcs2.c new file mode 100644 index 000000000000..a5a935a4f748 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/linked_funcs2.c @@ -0,0 +1,73 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2021 Facebook */ + +#include "vmlinux.h" +#include +#include + +/* weak and shared between both files */ +const volatile int my_tid __weak = 0; +const volatile long syscall_id __weak = 0; + +int output_val2 = 0; +int output_ctx2 = 0; +int output_weak2 = 0; /* should stay zero */ + +/* same "subprog" name in all files, but it's ok because they all are static */ +static __noinline int subprog(int x) +{ + /* but different formula */ + return x * 2; +} + +/* Global functions can't be void */ +int set_output_val2(int x) +{ + output_val2 = 2 * x + 2 * subprog(x); + return 2 * x; +} + +/* This function can't be verified as global, as it assumes raw_tp/sys_enter + * context and accesses syscall id (second argument). So we mark it as + * __hidden, so that libbpf will mark it as static in the final object file, + * right before verifying it in the kernel. + * + * But we don't mark it as __hidden here, rather at extern site. __hidden is + * "contaminating" visibility, so it will get propagated from either extern or + * actual definition (including from the losing __weak definition). + */ +void set_output_ctx2(__u64 *ctx) +{ + output_ctx2 = ctx[1]; /* long id, same as in BPF_PROG below */ +} + +/* this weak instance should lose, because it will be processed second */ +__weak int set_output_weak(int x) +{ + output_weak2 = x; + return 2 * x; +} + +extern int set_output_val1(int x); + +/* here we'll force set_output_ctx1() to be __hidden in the final obj file */ +__hidden extern void set_output_ctx1(__u64 *ctx); + +SEC("raw_tp/sys_enter") +int BPF_PROG(handler2, struct pt_regs *regs, long id) +{ + if (my_tid != (u32)bpf_get_current_pid_tgid() || id != syscall_id) + return 0; + + set_output_val1(2000); + set_output_ctx1(ctx); /* ctx definition is hidden in BPF_PROG macro */ + + /* keep input value the same across both files to avoid dependency on + * handler call order; differentiate by output_weak1 vs output_weak2. + */ + set_output_weak(42); + + return 0; +} + +char LICENSE[] SEC("license") = "GPL"; From patchwork Fri Apr 16 20:24:03 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrii Nakryiko X-Patchwork-Id: 12208737 X-Patchwork-Delegate: bpf@iogearbox.net 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=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 842C8C43461 for ; Fri, 16 Apr 2021 20:24:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6426B613D4 for ; Fri, 16 Apr 2021 20:24:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S244867AbhDPUZR convert rfc822-to-8bit (ORCPT ); Fri, 16 Apr 2021 16:25:17 -0400 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:64804 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1343703AbhDPUZJ (ORCPT ); Fri, 16 Apr 2021 16:25:09 -0400 Received: from pps.filterd (m0089730.ppops.net [127.0.0.1]) by m0089730.ppops.net (8.16.0.43/8.16.0.43) with SMTP id 13GKOeDq026614 for ; Fri, 16 Apr 2021 13:24:43 -0700 Received: from maileast.thefacebook.com ([163.114.130.16]) by m0089730.ppops.net with ESMTP id 37yb39jfxw-3 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Fri, 16 Apr 2021 13:24:43 -0700 Received: from intmgw006.03.ash8.facebook.com (2620:10d:c0a8:1b::d) by mail.thefacebook.com (2620:10d:c0a8:82::d) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Fri, 16 Apr 2021 13:24:42 -0700 Received: by devbig012.ftw2.facebook.com (Postfix, from userid 137359) id CC51B2ED4EE0; Fri, 16 Apr 2021 13:24:38 -0700 (PDT) From: Andrii Nakryiko To: , , , CC: , Subject: [PATCH v2 bpf-next 16/17] selftests/bpf: add global variables linking selftest Date: Fri, 16 Apr 2021 13:24:03 -0700 Message-ID: <20210416202404.3443623-17-andrii@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210416202404.3443623-1-andrii@kernel.org> References: <20210416202404.3443623-1-andrii@kernel.org> MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-ORIG-GUID: ybBNvfpG7s-kL_dSD4TDPDYgaZCe2pNS X-Proofpoint-GUID: ybBNvfpG7s-kL_dSD4TDPDYgaZCe2pNS X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.391,18.0.761 definitions=2021-04-16_09:2021-04-16,2021-04-16 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 adultscore=0 mlxlogscore=999 lowpriorityscore=0 suspectscore=0 malwarescore=0 clxscore=1015 impostorscore=0 mlxscore=0 priorityscore=1501 spamscore=0 bulkscore=0 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2104060000 definitions=main-2104160144 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net Add selftest validating various aspects of statically linking global variables: - correct resolution of extern variables across .bss, .data, and .rodata sections; - correct handling of weak definitions; - correct de-duplication of repeating special externs (.kconfig, .ksyms). Signed-off-by: Andrii Nakryiko Acked-by: Yonghong Song --- tools/testing/selftests/bpf/Makefile | 3 +- .../selftests/bpf/prog_tests/linked_vars.c | 43 +++++++++++++++ .../selftests/bpf/progs/linked_vars1.c | 54 ++++++++++++++++++ .../selftests/bpf/progs/linked_vars2.c | 55 +++++++++++++++++++ 4 files changed, 154 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/bpf/prog_tests/linked_vars.c create mode 100644 tools/testing/selftests/bpf/progs/linked_vars1.c create mode 100644 tools/testing/selftests/bpf/progs/linked_vars2.c diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile index 427ccfec1a6a..d8f176b55c01 100644 --- a/tools/testing/selftests/bpf/Makefile +++ b/tools/testing/selftests/bpf/Makefile @@ -308,10 +308,11 @@ endef SKEL_BLACKLIST := btf__% test_pinning_invalid.c test_sk_assign.c -LINKED_SKELS := test_static_linked.skel.h linked_funcs.skel.h +LINKED_SKELS := test_static_linked.skel.h linked_funcs.skel.h linked_vars.skel.h test_static_linked.skel.h-deps := test_static_linked1.o test_static_linked2.o linked_funcs.skel.h-deps := linked_funcs1.o linked_funcs2.o +linked_vars.skel.h-deps := linked_vars1.o linked_vars2.o LINKED_BPF_SRCS := $(patsubst %.o,%.c,$(foreach skel,$(LINKED_SKELS),$($(skel)-deps))) diff --git a/tools/testing/selftests/bpf/prog_tests/linked_vars.c b/tools/testing/selftests/bpf/prog_tests/linked_vars.c new file mode 100644 index 000000000000..f3d6ba31ef99 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/linked_vars.c @@ -0,0 +1,43 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2021 Facebook */ + +#include +#include +#include "linked_vars.skel.h" + +void test_linked_vars(void) +{ + int err; + struct linked_vars *skel; + + skel = linked_vars__open(); + if (!ASSERT_OK_PTR(skel, "skel_open")) + return; + + skel->bss->input_bss1 = 1000; + skel->bss->input_bss2 = 2000; + skel->bss->input_bss_weak = 3000; + + err = linked_vars__load(skel); + if (!ASSERT_OK(err, "skel_load")) + goto cleanup; + + err = linked_vars__attach(skel); + if (!ASSERT_OK(err, "skel_attach")) + goto cleanup; + + /* trigger */ + syscall(SYS_getpgid); + + ASSERT_EQ(skel->bss->output_bss1, 1000 + 2000 + 3000, "output_bss1"); + ASSERT_EQ(skel->bss->output_bss2, 1000 + 2000 + 3000, "output_bss2"); + /* 10 comes from "winner" input_data_weak in first obj file */ + ASSERT_EQ(skel->bss->output_data1, 1 + 2 + 10, "output_bss1"); + ASSERT_EQ(skel->bss->output_data2, 1 + 2 + 10, "output_bss2"); + /* 10 comes from "winner" input_rodata_weak in first obj file */ + ASSERT_EQ(skel->bss->output_rodata1, 11 + 22 + 100, "output_weak1"); + ASSERT_EQ(skel->bss->output_rodata2, 11 + 22 + 100, "output_weak2"); + +cleanup: + linked_vars__destroy(skel); +} diff --git a/tools/testing/selftests/bpf/progs/linked_vars1.c b/tools/testing/selftests/bpf/progs/linked_vars1.c new file mode 100644 index 000000000000..bc96eff9b8c1 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/linked_vars1.c @@ -0,0 +1,54 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2021 Facebook */ + +#include "vmlinux.h" +#include +#include + +extern int LINUX_KERNEL_VERSION __kconfig; +/* this weak extern will be strict due to the other file's strong extern */ +extern bool CONFIG_BPF_SYSCALL __kconfig __weak; +extern const void bpf_link_fops __ksym __weak; + +int input_bss1 = 0; +int input_data1 = 1; +const volatile int input_rodata1 = 11; + +int input_bss_weak __weak = 0; +/* these two definitions should win */ +int input_data_weak __weak = 10; +const volatile int input_rodata_weak __weak = 100; + +extern int input_bss2; +extern int input_data2; +extern const int input_rodata2; + +int output_bss1 = 0; +int output_data1 = 0; +int output_rodata1 = 0; + +long output_sink1 = 0; + +static __noinline int get_bss_res(void) +{ + /* just make sure all the relocations work against .text as well */ + return input_bss1 + input_bss2 + input_bss_weak; +} + +SEC("raw_tp/sys_enter") +int BPF_PROG(handler1) +{ + output_bss1 = get_bss_res(); + output_data1 = input_data1 + input_data2 + input_data_weak; + output_rodata1 = input_rodata1 + input_rodata2 + input_rodata_weak; + + /* make sure we actually use above special externs, otherwise compiler + * will optimize them out + */ + output_sink1 = LINUX_KERNEL_VERSION + + CONFIG_BPF_SYSCALL + + (long)&bpf_link_fops; + return 0; +} + +char LICENSE[] SEC("license") = "GPL"; diff --git a/tools/testing/selftests/bpf/progs/linked_vars2.c b/tools/testing/selftests/bpf/progs/linked_vars2.c new file mode 100644 index 000000000000..946c0ce4f505 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/linked_vars2.c @@ -0,0 +1,55 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2021 Facebook */ + +#include "vmlinux.h" +#include +#include + +extern int LINUX_KERNEL_VERSION __kconfig; +/* when an extern is defined as both strong and weak, resulting symbol will be strong */ +extern bool CONFIG_BPF_SYSCALL __kconfig; +extern const void __start_BTF __ksym; + +int input_bss2 = 0; +int input_data2 = 2; +const volatile int input_rodata2 = 22; + +int input_bss_weak __weak = 0; +/* these two weak variables should lose */ +int input_data_weak __weak = 20; +const volatile int input_rodata_weak __weak = 200; + +extern int input_bss1; +extern int input_data1; +extern const int input_rodata1; + +int output_bss2 = 0; +int output_data2 = 0; +int output_rodata2 = 0; + +int output_sink2 = 0; + +static __noinline int get_data_res(void) +{ + /* just make sure all the relocations work against .text as well */ + return input_data1 + input_data2 + input_data_weak; +} + +SEC("raw_tp/sys_enter") +int BPF_PROG(handler2) +{ + output_bss2 = input_bss1 + input_bss2 + input_bss_weak; + output_data2 = get_data_res(); + output_rodata2 = input_rodata1 + input_rodata2 + input_rodata_weak; + + /* make sure we actually use above special externs, otherwise compiler + * will optimize them out + */ + output_sink2 = LINUX_KERNEL_VERSION + + CONFIG_BPF_SYSCALL + + (long)&__start_BTF; + + return 0; +} + +char LICENSE[] SEC("license") = "GPL"; From patchwork Fri Apr 16 20:24:04 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Andrii Nakryiko X-Patchwork-Id: 12208739 X-Patchwork-Delegate: bpf@iogearbox.net 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 DD8C9C43462 for ; Fri, 16 Apr 2021 20:24:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id AE73C613D1 for ; Fri, 16 Apr 2021 20:24:53 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1343777AbhDPUZR convert rfc822-to-8bit (ORCPT ); Fri, 16 Apr 2021 16:25:17 -0400 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:5276 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1343707AbhDPUZK (ORCPT ); Fri, 16 Apr 2021 16:25:10 -0400 Received: from pps.filterd (m0089730.ppops.net [127.0.0.1]) by m0089730.ppops.net (8.16.0.43/8.16.0.43) with SMTP id 13GKOgZH026679 for ; Fri, 16 Apr 2021 13:24:44 -0700 Received: from maileast.thefacebook.com ([163.114.130.16]) by m0089730.ppops.net with ESMTP id 37yb39jfxv-7 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Fri, 16 Apr 2021 13:24:44 -0700 Received: from intmgw006.03.ash8.facebook.com (2620:10d:c0a8:1b::d) by mail.thefacebook.com (2620:10d:c0a8:83::6) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Fri, 16 Apr 2021 13:24:42 -0700 Received: by devbig012.ftw2.facebook.com (Postfix, from userid 137359) id D058F2ED4EE0; Fri, 16 Apr 2021 13:24:40 -0700 (PDT) From: Andrii Nakryiko To: , , , CC: , Subject: [PATCH v2 bpf-next 17/17] sleftests/bpf: add map linking selftest Date: Fri, 16 Apr 2021 13:24:04 -0700 Message-ID: <20210416202404.3443623-18-andrii@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210416202404.3443623-1-andrii@kernel.org> References: <20210416202404.3443623-1-andrii@kernel.org> MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-ORIG-GUID: 6rZSQGun9S3lIL2Cke5Kffppb_xI1D_K X-Proofpoint-GUID: 6rZSQGun9S3lIL2Cke5Kffppb_xI1D_K X-Proofpoint-Virus-Version: vendor=fsecure engine=2.50.10434:6.0.391,18.0.761 definitions=2021-04-16_09:2021-04-16,2021-04-16 signatures=0 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 adultscore=0 mlxlogscore=999 lowpriorityscore=0 suspectscore=0 malwarescore=0 clxscore=1015 impostorscore=0 mlxscore=0 priorityscore=1501 spamscore=0 bulkscore=0 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2104060000 definitions=main-2104160144 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net Add selftest validating various aspects of statically linking BTF-defined map definitions. Legacy map definitions do not support extern resolution between object files. Some of the aspects validated: - correct resolution of extern maps against concrete map definitions; - extern maps can currently only specify map type and key/value size and/or type information; - weak concrete map definitions are resolved properly. Static map definitions are not yet supported by libbpf, so they are not explicitly tested, though manual testing showes that BPF linker handles them properly. Signed-off-by: Andrii Nakryiko Acked-by: Yonghong Song --- tools/testing/selftests/bpf/Makefile | 4 +- .../selftests/bpf/prog_tests/linked_maps.c | 30 +++++++ .../selftests/bpf/progs/linked_maps1.c | 82 +++++++++++++++++++ .../selftests/bpf/progs/linked_maps2.c | 76 +++++++++++++++++ 4 files changed, 191 insertions(+), 1 deletion(-) create mode 100644 tools/testing/selftests/bpf/prog_tests/linked_maps.c create mode 100644 tools/testing/selftests/bpf/progs/linked_maps1.c create mode 100644 tools/testing/selftests/bpf/progs/linked_maps2.c diff --git a/tools/testing/selftests/bpf/Makefile b/tools/testing/selftests/bpf/Makefile index d8f176b55c01..9c031db16b25 100644 --- a/tools/testing/selftests/bpf/Makefile +++ b/tools/testing/selftests/bpf/Makefile @@ -308,11 +308,13 @@ endef SKEL_BLACKLIST := btf__% test_pinning_invalid.c test_sk_assign.c -LINKED_SKELS := test_static_linked.skel.h linked_funcs.skel.h linked_vars.skel.h +LINKED_SKELS := test_static_linked.skel.h linked_funcs.skel.h \ + linked_vars.skel.h linked_maps.skel.h test_static_linked.skel.h-deps := test_static_linked1.o test_static_linked2.o linked_funcs.skel.h-deps := linked_funcs1.o linked_funcs2.o linked_vars.skel.h-deps := linked_vars1.o linked_vars2.o +linked_maps.skel.h-deps := linked_maps1.o linked_maps2.o LINKED_BPF_SRCS := $(patsubst %.o,%.c,$(foreach skel,$(LINKED_SKELS),$($(skel)-deps))) diff --git a/tools/testing/selftests/bpf/prog_tests/linked_maps.c b/tools/testing/selftests/bpf/prog_tests/linked_maps.c new file mode 100644 index 000000000000..85dcaaaf2775 --- /dev/null +++ b/tools/testing/selftests/bpf/prog_tests/linked_maps.c @@ -0,0 +1,30 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2021 Facebook */ + +#include +#include +#include "linked_maps.skel.h" + +void test_linked_maps(void) +{ + int err; + struct linked_maps *skel; + + skel = linked_maps__open_and_load(); + if (!ASSERT_OK_PTR(skel, "skel_open")) + return; + + err = linked_maps__attach(skel); + if (!ASSERT_OK(err, "skel_attach")) + goto cleanup; + + /* trigger */ + syscall(SYS_getpgid); + + ASSERT_EQ(skel->bss->output_first1, 2000, "output_first1"); + ASSERT_EQ(skel->bss->output_second1, 2, "output_second1"); + ASSERT_EQ(skel->bss->output_weak1, 2, "output_weak1"); + +cleanup: + linked_maps__destroy(skel); +} diff --git a/tools/testing/selftests/bpf/progs/linked_maps1.c b/tools/testing/selftests/bpf/progs/linked_maps1.c new file mode 100644 index 000000000000..2f4bab565e64 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/linked_maps1.c @@ -0,0 +1,82 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2021 Facebook */ + +#include "vmlinux.h" +#include +#include + +struct my_key { long x; }; +struct my_value { long x; }; + +struct { + __uint(type, BPF_MAP_TYPE_HASH); + __type(key, struct my_key); + __type(value, struct my_value); + __uint(max_entries, 16); +} map1 SEC(".maps"); + + /* Matches map2 definition in linked_maps2.c. Order of the attributes doesn't + * matter. + */ +typedef struct { + __uint(max_entries, 8); + __type(key, int); + __type(value, int); + __uint(type, BPF_MAP_TYPE_ARRAY); +} map2_t; + +extern map2_t map2 SEC(".maps"); + +/* This should be the winning map definition, but we have no way of verifying, + * so we just make sure that it links and works without errors + */ +struct { + __uint(type, BPF_MAP_TYPE_ARRAY); + __type(key, int); + __type(value, int); + __uint(max_entries, 16); +} map_weak __weak SEC(".maps"); + +int output_first1 = 0; +int output_second1 = 0; +int output_weak1 = 0; + +SEC("raw_tp/sys_enter") +int BPF_PROG(handler_enter1) +{ + /* update values with key = 1 */ + int key = 1, val = 1; + struct my_key key_struct = { .x = 1 }; + struct my_value val_struct = { .x = 1000 }; + + bpf_map_update_elem(&map1, &key_struct, &val_struct, 0); + bpf_map_update_elem(&map2, &key, &val, 0); + bpf_map_update_elem(&map_weak, &key, &val, 0); + + return 0; +} + +SEC("raw_tp/sys_exit") +int BPF_PROG(handler_exit1) +{ + /* lookup values with key = 2, set in another file */ + int key = 2, *val; + struct my_key key_struct = { .x = 2 }; + struct my_value *value_struct; + + value_struct = bpf_map_lookup_elem(&map1, &key_struct); + if (value_struct) + output_first1 = value_struct->x; + + val = bpf_map_lookup_elem(&map2, &key); + if (val) + output_second1 = *val; + + val = bpf_map_lookup_elem(&map_weak, &key); + if (val) + output_weak1 = *val; + + return 0; +} + +char LICENSE[] SEC("license") = "GPL"; diff --git a/tools/testing/selftests/bpf/progs/linked_maps2.c b/tools/testing/selftests/bpf/progs/linked_maps2.c new file mode 100644 index 000000000000..3f1490ea8f37 --- /dev/null +++ b/tools/testing/selftests/bpf/progs/linked_maps2.c @@ -0,0 +1,76 @@ +// SPDX-License-Identifier: GPL-2.0 +/* Copyright (c) 2021 Facebook */ + +#include "vmlinux.h" +#include +#include + +/* modifiers and typedefs are ignored when comparing key/value types */ +typedef struct my_key { long x; } key_type; +typedef struct my_value { long x; } value_type; + +extern struct { + __uint(max_entries, 16); + __type(key, key_type); + __type(value, value_type); + __uint(type, BPF_MAP_TYPE_HASH); +} map1 SEC(".maps"); + +struct { + __uint(type, BPF_MAP_TYPE_ARRAY); + __type(key, int); + __type(value, int); + __uint(max_entries, 8); +} map2 SEC(".maps"); + +/* this definition will lose, but it has to exactly match the winner */ +struct { + __uint(type, BPF_MAP_TYPE_ARRAY); + __type(key, int); + __type(value, int); + __uint(max_entries, 16); +} map_weak __weak SEC(".maps"); + +int output_first2 = 0; +int output_second2 = 0; +int output_weak2 = 0; + +SEC("raw_tp/sys_enter") +int BPF_PROG(handler_enter2) +{ + /* update values with key = 2 */ + int key = 2, val = 2; + key_type key_struct = { .x = 2 }; + value_type val_struct = { .x = 2000 }; + + bpf_map_update_elem(&map1, &key_struct, &val_struct, 0); + bpf_map_update_elem(&map2, &key, &val, 0); + bpf_map_update_elem(&map_weak, &key, &val, 0); + + return 0; +} + +SEC("raw_tp/sys_exit") +int BPF_PROG(handler_exit2) +{ + /* lookup values with key = 1, set in another file */ + int key = 1, *val; + key_type key_struct = { .x = 1 }; + value_type *value_struct; + + value_struct = bpf_map_lookup_elem(&map1, &key_struct); + if (value_struct) + output_first2 = value_struct->x; + + val = bpf_map_lookup_elem(&map2, &key); + if (val) + output_second2 = *val; + + val = bpf_map_lookup_elem(&map_weak, &key); + if (val) + output_weak2 = *val; + + return 0; +} + +char LICENSE[] SEC("license") = "GPL";