From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-19.1 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, 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 A7230C433FE for ; Tue, 14 Sep 2021 22:30:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 8733C6103B for ; Tue, 14 Sep 2021 22:30:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235505AbhINWbn (ORCPT ); Tue, 14 Sep 2021 18:31:43 -0400 Received: from mx0b-00082601.pphosted.com ([67.231.153.30]:10958 "EHLO mx0b-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235137AbhINWbn (ORCPT ); Tue, 14 Sep 2021 18:31:43 -0400 Received: from pps.filterd (m0109332.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.1.2/8.16.0.43) with SMTP id 18EG1gm0016116 for ; Tue, 14 Sep 2021 15:30:25 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : content-type : content-transfer-encoding : mime-version; s=facebook; bh=WofbbFgitWK2SZYfVbTTPTLk/uipJOFRf0OcvwZnl18=; b=jQjHfznARjILXmlHQiDxNQwZa9Ic7XXQfpMcB6CPVhvkxS2vL2vxCNp7gEhNcL7zE1Dn +KA10il99DmgJFuJuma2ozYMt8OQm75K2zFMTQ9qwA46zhrH5vdXtl+t9eGamJbENGog pm0/A+vXzxN3MfgzzZOFzmRtfEgeevXLgk0= Received: from mail.thefacebook.com ([163.114.132.120]) by mx0a-00082601.pphosted.com with ESMTP id 3b2s334m0x-6 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Tue, 14 Sep 2021 15:30:24 -0700 Received: from intmgw001.05.ash9.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 15.1.2308.14; Tue, 14 Sep 2021 15:30:20 -0700 Received: by devbig003.ftw2.facebook.com (Postfix, from userid 128203) id 1749C738218E; Tue, 14 Sep 2021 15:30:15 -0700 (PDT) From: Yonghong Song To: CC: Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , Subject: [PATCH bpf-next v3 02/11] bpf: support for new btf kind BTF_KIND_TAG Date: Tue, 14 Sep 2021 15:30:15 -0700 Message-ID: <20210914223015.245546-1-yhs@fb.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210914223004.244411-1-yhs@fb.com> References: <20210914223004.244411-1-yhs@fb.com> X-FB-Internal: Safe Content-Type: text/plain X-FB-Source: Intern X-Proofpoint-GUID: JgDSrB_BZamQoo5XwDPGaZNrbIpjhpCz X-Proofpoint-ORIG-GUID: JgDSrB_BZamQoo5XwDPGaZNrbIpjhpCz Content-Transfer-Encoding: quoted-printable X-Proofpoint-UnRewURL: 0 URL was un-rewritten MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.182.1,Aquarius:18.0.790,Hydra:6.0.391,FMLib:17.0.607.475 definitions=2021-09-14_08,2021-09-14_01,2020-04-07_01 X-Proofpoint-Spam-Details: rule=fb_default_notspam policy=fb_default score=0 impostorscore=0 priorityscore=1501 adultscore=0 clxscore=1015 lowpriorityscore=0 mlxlogscore=999 phishscore=0 spamscore=0 malwarescore=0 bulkscore=0 suspectscore=0 mlxscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2109030001 definitions=main-2109140129 X-FB-Internal: deliver Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org LLVM14 added support for a new C attribute ([1]) __attribute__((btf_tag("arbitrary_str"))) This attribute will be emitted to dwarf ([2]) and pahole will convert it to BTF. Or for bpf target, this attribute will be emitted to BTF directly ([3], [4]). The attribute is intended to provide additional information for - struct/union type or struct/union member - static/global variables - static/global function or function parameter. For linux kernel, the btf_tag can be applied in various places to specify user pointer, function pre- or post- condition, function allow/deny in certain context, etc. Such information will be encoded in vmlinux BTF and can be used by verifier. The btf_tag can also be applied to bpf programs to help global verifiable functions, e.g., specifying preconditions, etc. This patch added basic parsing and checking support in kernel for new BTF_KIND_TAG kind. [1] https://reviews.llvm.org/D106614 [2] https://reviews.llvm.org/D106621 [3] https://reviews.llvm.org/D106622 [4] https://reviews.llvm.org/D109560 Signed-off-by: Yonghong Song --- include/uapi/linux/btf.h | 14 +++- kernel/bpf/btf.c | 128 +++++++++++++++++++++++++++++++++ tools/include/uapi/linux/btf.h | 14 +++- 3 files changed, 154 insertions(+), 2 deletions(-) diff --git a/include/uapi/linux/btf.h b/include/uapi/linux/btf.h index 10e401073dd1..642b6ecb37d7 100644 --- a/include/uapi/linux/btf.h +++ b/include/uapi/linux/btf.h @@ -43,7 +43,7 @@ struct btf_type { * "size" tells the size of the type it is describing. * * "type" is used by PTR, TYPEDEF, VOLATILE, CONST, RESTRICT, - * FUNC, FUNC_PROTO and VAR. + * FUNC, FUNC_PROTO, VAR and TAG. * "type" is a type_id referring to another type. */ union { @@ -74,6 +74,7 @@ enum { BTF_KIND_VAR =3D 14, /* Variable */ BTF_KIND_DATASEC =3D 15, /* Section */ BTF_KIND_FLOAT =3D 16, /* Floating point */ + BTF_KIND_TAG =3D 17, /* Tag */ =20 NR_BTF_KINDS, BTF_KIND_MAX =3D NR_BTF_KINDS - 1, @@ -173,4 +174,15 @@ struct btf_var_secinfo { __u32 size; }; =20 +/* BTF_KIND_TAG is followed by a single "struct btf_tag" to describe + * additional information related to the tag applied location. + * If component_idx =3D=3D -1, the tag is applied to a struct, union, + * variable or function. Otherwise, it is applied to a struct/union + * member or a func argument, and component_idx indicates which member + * or argument (0 ... vlen-1). + */ +struct btf_tag { + __s32 component_idx; +}; + #endif /* _UAPI__LINUX_BTF_H__ */ diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index dfe61df4f974..c3d605b22473 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -281,6 +281,7 @@ static const char * const btf_kind_str[NR_BTF_KINDS] = =3D { [BTF_KIND_VAR] =3D "VAR", [BTF_KIND_DATASEC] =3D "DATASEC", [BTF_KIND_FLOAT] =3D "FLOAT", + [BTF_KIND_TAG] =3D "TAG", }; =20 const char *btf_type_str(const struct btf_type *t) @@ -459,6 +460,17 @@ static bool btf_type_is_datasec(const struct btf_type = *t) return BTF_INFO_KIND(t->info) =3D=3D BTF_KIND_DATASEC; } =20 +static bool btf_type_is_tag(const struct btf_type *t) +{ + return BTF_INFO_KIND(t->info) =3D=3D BTF_KIND_TAG; +} + +static bool btf_type_is_tag_target(const struct btf_type *t) +{ + return btf_type_is_func(t) || btf_type_is_struct(t) || + btf_type_is_var(t); +} + u32 btf_nr_types(const struct btf *btf) { u32 total =3D 0; @@ -537,6 +549,7 @@ const struct btf_type *btf_type_resolve_func_ptr(const = struct btf *btf, static bool btf_type_is_resolve_source_only(const struct btf_type *t) { return btf_type_is_var(t) || + btf_type_is_tag(t) || btf_type_is_datasec(t); } =20 @@ -563,6 +576,7 @@ static bool btf_type_needs_resolve(const struct btf_typ= e *t) btf_type_is_struct(t) || btf_type_is_array(t) || btf_type_is_var(t) || + btf_type_is_tag(t) || btf_type_is_datasec(t); } =20 @@ -616,6 +630,11 @@ static const struct btf_var *btf_type_var(const struct= btf_type *t) return (const struct btf_var *)(t + 1); } =20 +static const struct btf_tag *btf_type_tag(const struct btf_type *t) +{ + return (const struct btf_tag *)(t + 1); +} + static const struct btf_kind_operations *btf_type_ops(const struct btf_typ= e *t) { return kind_ops[BTF_INFO_KIND(t->info)]; @@ -3801,6 +3820,110 @@ static const struct btf_kind_operations float_ops = =3D { .show =3D btf_df_show, }; =20 +static s32 btf_tag_check_meta(struct btf_verifier_env *env, + const struct btf_type *t, + u32 meta_left) +{ + const struct btf_tag *tag; + u32 meta_needed =3D sizeof(*tag); + s32 component_idx; + const char *value; + + if (meta_left < meta_needed) { + btf_verifier_log_basic(env, t, + "meta_left:%u meta_needed:%u", + meta_left, meta_needed); + return -EINVAL; + } + + value =3D btf_name_by_offset(env->btf, t->name_off); + if (!value || !value[0]) { + btf_verifier_log_type(env, t, "Invalid value"); + return -EINVAL; + } + + if (btf_type_vlen(t)) { + btf_verifier_log_type(env, t, "vlen !=3D 0"); + return -EINVAL; + } + + if (btf_type_kflag(t)) { + btf_verifier_log_type(env, t, "Invalid btf_info kind_flag"); + return -EINVAL; + } + + component_idx =3D btf_type_tag(t)->component_idx; + if (component_idx < -1) { + btf_verifier_log_type(env, t, "Invalid component_idx"); + return -EINVAL; + } + + btf_verifier_log_type(env, t, NULL); + + return meta_needed; +} + +static int btf_tag_resolve(struct btf_verifier_env *env, + const struct resolve_vertex *v) +{ + const struct btf_type *next_type; + const struct btf_type *t =3D v->t; + u32 next_type_id =3D t->type; + struct btf *btf =3D env->btf; + s32 component_idx; + u32 vlen; + + next_type =3D btf_type_by_id(btf, next_type_id); + if (!next_type || !btf_type_is_tag_target(next_type)) { + btf_verifier_log_type(env, v->t, "Invalid type_id"); + return -EINVAL; + } + + if (!env_type_is_resolve_sink(env, next_type) && + !env_type_is_resolved(env, next_type_id)) + return env_stack_push(env, next_type, next_type_id); + + component_idx =3D btf_type_tag(t)->component_idx; + if (component_idx !=3D -1) { + if (btf_type_is_var(next_type)) { + btf_verifier_log_type(env, v->t, "Invalid component_idx"); + return -EINVAL; + } + + if (btf_type_is_struct(next_type)) { + vlen =3D btf_type_vlen(next_type); + } else { + /* next_type should be a function */ + next_type =3D btf_type_by_id(btf, next_type->type); + vlen =3D btf_type_vlen(next_type); + } + + if ((u32)component_idx >=3D vlen) { + btf_verifier_log_type(env, v->t, "Invalid component_idx"); + return -EINVAL; + } + } + + env_stack_pop_resolved(env, next_type_id, 0); + + return 0; +} + +static void btf_tag_log(struct btf_verifier_env *env, const struct btf_typ= e *t) +{ + btf_verifier_log(env, "type=3D%u component_idx=3D%d", t->type, + btf_type_tag(t)->component_idx); +} + +static const struct btf_kind_operations tag_ops =3D { + .check_meta =3D btf_tag_check_meta, + .resolve =3D btf_tag_resolve, + .check_member =3D btf_df_check_member, + .check_kflag_member =3D btf_df_check_kflag_member, + .log_details =3D btf_tag_log, + .show =3D btf_df_show, +}; + static int btf_func_proto_check(struct btf_verifier_env *env, const struct btf_type *t) { @@ -3935,6 +4058,7 @@ static const struct btf_kind_operations * const kind_= ops[NR_BTF_KINDS] =3D { [BTF_KIND_VAR] =3D &var_ops, [BTF_KIND_DATASEC] =3D &datasec_ops, [BTF_KIND_FLOAT] =3D &float_ops, + [BTF_KIND_TAG] =3D &tag_ops, }; =20 static s32 btf_check_meta(struct btf_verifier_env *env, @@ -4019,6 +4143,10 @@ static bool btf_resolve_valid(struct btf_verifier_en= v *env, return !btf_resolved_type_id(btf, type_id) && !btf_resolved_type_size(btf, type_id); =20 + if (btf_type_is_tag(t)) + return btf_resolved_type_id(btf, type_id) && + !btf_resolved_type_size(btf, type_id); + if (btf_type_is_modifier(t) || btf_type_is_ptr(t) || btf_type_is_var(t)) { t =3D btf_type_id_resolve(btf, &type_id); diff --git a/tools/include/uapi/linux/btf.h b/tools/include/uapi/linux/btf.h index 10e401073dd1..642b6ecb37d7 100644 --- a/tools/include/uapi/linux/btf.h +++ b/tools/include/uapi/linux/btf.h @@ -43,7 +43,7 @@ struct btf_type { * "size" tells the size of the type it is describing. * * "type" is used by PTR, TYPEDEF, VOLATILE, CONST, RESTRICT, - * FUNC, FUNC_PROTO and VAR. + * FUNC, FUNC_PROTO, VAR and TAG. * "type" is a type_id referring to another type. */ union { @@ -74,6 +74,7 @@ enum { BTF_KIND_VAR =3D 14, /* Variable */ BTF_KIND_DATASEC =3D 15, /* Section */ BTF_KIND_FLOAT =3D 16, /* Floating point */ + BTF_KIND_TAG =3D 17, /* Tag */ =20 NR_BTF_KINDS, BTF_KIND_MAX =3D NR_BTF_KINDS - 1, @@ -173,4 +174,15 @@ struct btf_var_secinfo { __u32 size; }; =20 +/* BTF_KIND_TAG is followed by a single "struct btf_tag" to describe + * additional information related to the tag applied location. + * If component_idx =3D=3D -1, the tag is applied to a struct, union, + * variable or function. Otherwise, it is applied to a struct/union + * member or a func argument, and component_idx indicates which member + * or argument (0 ... vlen-1). + */ +struct btf_tag { + __s32 component_idx; +}; + #endif /* _UAPI__LINUX_BTF_H__ */ --=20 2.30.2