From patchwork Tue Jun 7 06:26:00 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Yonghong Song X-Patchwork-Id: 12871385 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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C2F7AC43334 for ; Tue, 7 Jun 2022 06:26:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236970AbiFGG0Q (ORCPT ); Tue, 7 Jun 2022 02:26:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:58398 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230086AbiFGG0O (ORCPT ); Tue, 7 Jun 2022 02:26:14 -0400 Received: from mx0a-00082601.pphosted.com (mx0a-00082601.pphosted.com [67.231.145.42]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3B402C967B for ; Mon, 6 Jun 2022 23:26:13 -0700 (PDT) Received: from pps.filterd (m0044010.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.17.1.5/8.17.1.5) with ESMTP id 25765CJi015479 for ; Mon, 6 Jun 2022 23:26:13 -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=G7+VrzFZBovgO4c96JDgzSX9u2glV/AK/7qDX9m2azI=; b=aT2z570gnQF/AAgyT1mhDA8t4WYSO9CxdnMxndvhNTNTk9K02O7BKC974tivx0TT7Hc6 98SznKkN1aNuDvnmmQP3fAPFAI6VDG/NQtbJ2Uc7A0aP8R0adV63HLaVbHWpVzE2b1dk vfxdAUGjHdCtubygWnyyOaA20KAR9rif63w= Received: from mail.thefacebook.com ([163.114.132.120]) by mx0a-00082601.pphosted.com (PPS) with ESMTPS id 3gj13cg2de-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Mon, 06 Jun 2022 23:26:12 -0700 Received: from twshared5413.23.frc3.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 15.1.2375.28; Mon, 6 Jun 2022 23:26:12 -0700 Received: by devbig309.ftw3.facebook.com (Postfix, from userid 128203) id 39510B520ED3; Mon, 6 Jun 2022 23:26:00 -0700 (PDT) From: Yonghong Song To: CC: Alexei Starovoitov , Andrii Nakryiko , Daniel Borkmann , Subject: [PATCH bpf-next v5 01/17] bpf: Add btf enum64 support Date: Mon, 6 Jun 2022 23:26:00 -0700 Message-ID: <20220607062600.3716578-1-yhs@fb.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220607062554.3716237-1-yhs@fb.com> References: <20220607062554.3716237-1-yhs@fb.com> X-FB-Internal: Safe X-Proofpoint-GUID: YwSWFFl9DItByl7iQAM_8kAeSUBC8u5g X-Proofpoint-ORIG-GUID: YwSWFFl9DItByl7iQAM_8kAeSUBC8u5g X-Proofpoint-UnRewURL: 0 URL was un-rewritten MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.874,Hydra:6.0.517,FMLib:17.11.64.514 definitions=2022-06-07_02,2022-06-03_01,2022-02-23_01 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net Currently, BTF only supports upto 32bit enum value with BTF_KIND_ENUM. But in kernel, some enum indeed has 64bit values, e.g., in uapi bpf.h, we have enum { BPF_F_INDEX_MASK = 0xffffffffULL, BPF_F_CURRENT_CPU = BPF_F_INDEX_MASK, BPF_F_CTXLEN_MASK = (0xfffffULL << 32), }; In this case, BTF_KIND_ENUM will encode the value of BPF_F_CTXLEN_MASK as 0, which certainly is incorrect. This patch added a new btf kind, BTF_KIND_ENUM64, which permits 64bit value to cover the above use case. The BTF_KIND_ENUM64 has the following three fields followed by the common type: struct bpf_enum64 { __u32 nume_off; __u32 val_lo32; __u32 val_hi32; }; Currently, btf type section has an alignment of 4 as all element types are u32. Representing the value with __u64 will introduce a pad for bpf_enum64 and may also introduce misalignment for the 64bit value. Hence, two members of val_hi32 and val_lo32 are chosen to avoid these issues. The kflag is also introduced for BTF_KIND_ENUM and BTF_KIND_ENUM64 to indicate whether the value is signed or unsigned. The kflag intends to provide consistent output of BTF C fortmat with the original source code. For example, the original BTF_KIND_ENUM bit value is 0xffffffff. The format C has two choices, printing out 0xffffffff or -1 and current libbpf prints out as unsigned value. But if the signedness is preserved in btf, the value can be printed the same as the original source code. The kflag value 0 means unsigned values, which is consistent to the default by libbpf and should also cover most cases as well. The new BTF_KIND_ENUM64 is intended to support the enum value represented as 64bit value. But it can represent all BTF_KIND_ENUM values as well. The compiler ([1]) and pahole will generate BTF_KIND_ENUM64 only if the value has to be represented with 64 bits. In addition, a static inline function btf_kind_core_compat() is introduced which will be used later when libbpf relo_core.c changed. Here the kernel shares the same relo_core.c with libbpf. [1] https://reviews.llvm.org/D124641 Acked-by: Andrii Nakryiko Signed-off-by: Yonghong Song --- include/linux/btf.h | 28 +++++++ include/uapi/linux/btf.h | 17 +++- kernel/bpf/btf.c | 142 +++++++++++++++++++++++++++++---- kernel/bpf/verifier.c | 2 +- tools/include/uapi/linux/btf.h | 17 +++- 5 files changed, 185 insertions(+), 21 deletions(-) diff --git a/include/linux/btf.h b/include/linux/btf.h index 2611cea2c2b6..1bfed7fa0428 100644 --- a/include/linux/btf.h +++ b/include/linux/btf.h @@ -177,6 +177,19 @@ static inline bool btf_type_is_enum(const struct btf_type *t) return BTF_INFO_KIND(t->info) == BTF_KIND_ENUM; } +static inline bool btf_is_any_enum(const struct btf_type *t) +{ + return BTF_INFO_KIND(t->info) == BTF_KIND_ENUM || + BTF_INFO_KIND(t->info) == BTF_KIND_ENUM64; +} + +static inline bool btf_kind_core_compat(const struct btf_type *t1, + const struct btf_type *t2) +{ + return BTF_INFO_KIND(t1->info) == BTF_INFO_KIND(t2->info) || + (btf_is_any_enum(t1) && btf_is_any_enum(t2)); +} + static inline bool str_is_empty(const char *s) { return !s || !s[0]; @@ -192,6 +205,16 @@ static inline bool btf_is_enum(const struct btf_type *t) return btf_kind(t) == BTF_KIND_ENUM; } +static inline bool btf_is_enum64(const struct btf_type *t) +{ + return btf_kind(t) == BTF_KIND_ENUM64; +} + +static inline u64 btf_enum64_value(const struct btf_enum64 *e) +{ + return ((u64)e->val_hi32 << 32) | e->val_lo32; +} + static inline bool btf_is_composite(const struct btf_type *t) { u16 kind = btf_kind(t); @@ -332,6 +355,11 @@ static inline struct btf_enum *btf_enum(const struct btf_type *t) return (struct btf_enum *)(t + 1); } +static inline struct btf_enum64 *btf_enum64(const struct btf_type *t) +{ + return (struct btf_enum64 *)(t + 1); +} + static inline const struct btf_var_secinfo *btf_type_var_secinfo( const struct btf_type *t) { diff --git a/include/uapi/linux/btf.h b/include/uapi/linux/btf.h index a9162a6c0284..ec1798b6d3ff 100644 --- a/include/uapi/linux/btf.h +++ b/include/uapi/linux/btf.h @@ -36,10 +36,10 @@ struct btf_type { * bits 24-28: kind (e.g. int, ptr, array...etc) * bits 29-30: unused * bit 31: kind_flag, currently used by - * struct, union and fwd + * struct, union, enum, fwd and enum64 */ __u32 info; - /* "size" is used by INT, ENUM, STRUCT, UNION and DATASEC. + /* "size" is used by INT, ENUM, STRUCT, UNION, DATASEC and ENUM64. * "size" tells the size of the type it is describing. * * "type" is used by PTR, TYPEDEF, VOLATILE, CONST, RESTRICT, @@ -63,7 +63,7 @@ enum { BTF_KIND_ARRAY = 3, /* Array */ BTF_KIND_STRUCT = 4, /* Struct */ BTF_KIND_UNION = 5, /* Union */ - BTF_KIND_ENUM = 6, /* Enumeration */ + BTF_KIND_ENUM = 6, /* Enumeration up to 32-bit values */ BTF_KIND_FWD = 7, /* Forward */ BTF_KIND_TYPEDEF = 8, /* Typedef */ BTF_KIND_VOLATILE = 9, /* Volatile */ @@ -76,6 +76,7 @@ enum { BTF_KIND_FLOAT = 16, /* Floating point */ BTF_KIND_DECL_TAG = 17, /* Decl Tag */ BTF_KIND_TYPE_TAG = 18, /* Type Tag */ + BTF_KIND_ENUM64 = 19, /* Enumeration up to 64-bit values */ NR_BTF_KINDS, BTF_KIND_MAX = NR_BTF_KINDS - 1, @@ -186,4 +187,14 @@ struct btf_decl_tag { __s32 component_idx; }; +/* BTF_KIND_ENUM64 is followed by multiple "struct btf_enum64". + * The exact number of btf_enum64 is stored in the vlen (of the + * info in "struct btf_type"). + */ +struct btf_enum64 { + __u32 name_off; + __u32 val_lo32; + __u32 val_hi32; +}; + #endif /* _UAPI__LINUX_BTF_H__ */ diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index 7bccaa4646e5..6c0d8480e15c 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -309,6 +309,7 @@ static const char * const btf_kind_str[NR_BTF_KINDS] = { [BTF_KIND_FLOAT] = "FLOAT", [BTF_KIND_DECL_TAG] = "DECL_TAG", [BTF_KIND_TYPE_TAG] = "TYPE_TAG", + [BTF_KIND_ENUM64] = "ENUM64", }; const char *btf_type_str(const struct btf_type *t) @@ -666,6 +667,7 @@ static bool btf_type_has_size(const struct btf_type *t) case BTF_KIND_ENUM: case BTF_KIND_DATASEC: case BTF_KIND_FLOAT: + case BTF_KIND_ENUM64: return true; } @@ -711,6 +713,11 @@ static const struct btf_decl_tag *btf_type_decl_tag(const struct btf_type *t) return (const struct btf_decl_tag *)(t + 1); } +static const struct btf_enum64 *btf_type_enum64(const struct btf_type *t) +{ + return (const struct btf_enum64 *)(t + 1); +} + static const struct btf_kind_operations *btf_type_ops(const struct btf_type *t) { return kind_ops[BTF_INFO_KIND(t->info)]; @@ -1019,6 +1026,7 @@ static const char *btf_show_name(struct btf_show *show) parens = "{"; break; case BTF_KIND_ENUM: + case BTF_KIND_ENUM64: prefix = "enum"; break; default: @@ -1834,6 +1842,7 @@ __btf_resolve_size(const struct btf *btf, const struct btf_type *type, case BTF_KIND_UNION: case BTF_KIND_ENUM: case BTF_KIND_FLOAT: + case BTF_KIND_ENUM64: size = type->size; goto resolved; @@ -3670,6 +3679,7 @@ static s32 btf_enum_check_meta(struct btf_verifier_env *env, { const struct btf_enum *enums = btf_type_enum(t); struct btf *btf = env->btf; + const char *fmt_str; u16 i, nr_enums; u32 meta_needed; @@ -3683,11 +3693,6 @@ static s32 btf_enum_check_meta(struct btf_verifier_env *env, return -EINVAL; } - if (btf_type_kflag(t)) { - btf_verifier_log_type(env, t, "Invalid btf_info kind_flag"); - return -EINVAL; - } - if (t->size > 8 || !is_power_of_2(t->size)) { btf_verifier_log_type(env, t, "Unexpected size"); return -EINVAL; @@ -3718,7 +3723,8 @@ static s32 btf_enum_check_meta(struct btf_verifier_env *env, if (env->log.level == BPF_LOG_KERNEL) continue; - btf_verifier_log(env, "\t%s val=%d\n", + fmt_str = btf_type_kflag(t) ? "\t%s val=%d\n" : "\t%s val=%u\n"; + btf_verifier_log(env, fmt_str, __btf_name_by_offset(btf, enums[i].name_off), enums[i].val); } @@ -3759,7 +3765,10 @@ static void btf_enum_show(const struct btf *btf, const struct btf_type *t, return; } - btf_show_type_value(show, "%d", v); + if (btf_type_kflag(t)) + btf_show_type_value(show, "%d", v); + else + btf_show_type_value(show, "%u", v); btf_show_end_type(show); } @@ -3772,6 +3781,109 @@ static struct btf_kind_operations enum_ops = { .show = btf_enum_show, }; +static s32 btf_enum64_check_meta(struct btf_verifier_env *env, + const struct btf_type *t, + u32 meta_left) +{ + const struct btf_enum64 *enums = btf_type_enum64(t); + struct btf *btf = env->btf; + const char *fmt_str; + u16 i, nr_enums; + u32 meta_needed; + + nr_enums = btf_type_vlen(t); + meta_needed = nr_enums * sizeof(*enums); + + if (meta_left < meta_needed) { + btf_verifier_log_basic(env, t, + "meta_left:%u meta_needed:%u", + meta_left, meta_needed); + return -EINVAL; + } + + if (t->size > 8 || !is_power_of_2(t->size)) { + btf_verifier_log_type(env, t, "Unexpected size"); + return -EINVAL; + } + + /* enum type either no name or a valid one */ + if (t->name_off && + !btf_name_valid_identifier(env->btf, t->name_off)) { + btf_verifier_log_type(env, t, "Invalid name"); + return -EINVAL; + } + + btf_verifier_log_type(env, t, NULL); + + for (i = 0; i < nr_enums; i++) { + if (!btf_name_offset_valid(btf, enums[i].name_off)) { + btf_verifier_log(env, "\tInvalid name_offset:%u", + enums[i].name_off); + return -EINVAL; + } + + /* enum member must have a valid name */ + if (!enums[i].name_off || + !btf_name_valid_identifier(btf, enums[i].name_off)) { + btf_verifier_log_type(env, t, "Invalid name"); + return -EINVAL; + } + + if (env->log.level == BPF_LOG_KERNEL) + continue; + + fmt_str = btf_type_kflag(t) ? "\t%s val=%lld\n" : "\t%s val=%llu\n"; + btf_verifier_log(env, fmt_str, + __btf_name_by_offset(btf, enums[i].name_off), + btf_enum64_value(enums + i)); + } + + return meta_needed; +} + +static void btf_enum64_show(const struct btf *btf, const struct btf_type *t, + u32 type_id, void *data, u8 bits_offset, + struct btf_show *show) +{ + const struct btf_enum64 *enums = btf_type_enum64(t); + u32 i, nr_enums = btf_type_vlen(t); + void *safe_data; + s64 v; + + safe_data = btf_show_start_type(show, t, type_id, data); + if (!safe_data) + return; + + v = *(u64 *)safe_data; + + for (i = 0; i < nr_enums; i++) { + if (v != btf_enum64_value(enums + i)) + continue; + + btf_show_type_value(show, "%s", + __btf_name_by_offset(btf, + enums[i].name_off)); + + btf_show_end_type(show); + return; + } + + if (btf_type_kflag(t)) + btf_show_type_value(show, "%lld", v); + else + btf_show_type_value(show, "%llu", v); + btf_show_end_type(show); +} + +static struct btf_kind_operations enum64_ops = { + .check_meta = btf_enum64_check_meta, + .resolve = btf_df_resolve, + .check_member = btf_enum_check_member, + .check_kflag_member = btf_enum_check_kflag_member, + .log_details = btf_enum_log, + .show = btf_enum64_show, +}; + static s32 btf_func_proto_check_meta(struct btf_verifier_env *env, const struct btf_type *t, u32 meta_left) @@ -4438,6 +4550,7 @@ static const struct btf_kind_operations * const kind_ops[NR_BTF_KINDS] = { [BTF_KIND_FLOAT] = &float_ops, [BTF_KIND_DECL_TAG] = &decl_tag_ops, [BTF_KIND_TYPE_TAG] = &modifier_ops, + [BTF_KIND_ENUM64] = &enum64_ops, }; static s32 btf_check_meta(struct btf_verifier_env *env, @@ -5299,7 +5412,7 @@ bool btf_ctx_access(int off, int size, enum bpf_access_type type, /* skip modifiers */ while (btf_type_is_modifier(t)) t = btf_type_by_id(btf, t->type); - if (btf_type_is_small_int(t) || btf_type_is_enum(t)) + if (btf_type_is_small_int(t) || btf_is_any_enum(t)) /* accessing a scalar */ return true; if (!btf_type_is_ptr(t)) { @@ -5763,7 +5876,7 @@ static int __get_type_size(struct btf *btf, u32 btf_id, if (btf_type_is_ptr(t)) /* kernel size of pointer. Not BPF's size of pointer*/ return sizeof(void *); - if (btf_type_is_int(t) || btf_type_is_enum(t)) + if (btf_type_is_int(t) || btf_is_any_enum(t)) return t->size; *bad_type = t; return -EINVAL; @@ -5911,7 +6024,7 @@ static int btf_check_func_type_match(struct bpf_verifier_log *log, * to context only. And only global functions can be replaced. * Hence type check only those types. */ - if (btf_type_is_int(t1) || btf_type_is_enum(t1)) + if (btf_type_is_int(t1) || btf_is_any_enum(t1)) continue; if (!btf_type_is_ptr(t1)) { bpf_log(log, @@ -6408,7 +6521,7 @@ int btf_prepare_func_args(struct bpf_verifier_env *env, int subprog, t = btf_type_by_id(btf, t->type); while (btf_type_is_modifier(t)) t = btf_type_by_id(btf, t->type); - if (!btf_type_is_int(t) && !btf_type_is_enum(t)) { + if (!btf_type_is_int(t) && !btf_is_any_enum(t)) { bpf_log(log, "Global function %s() doesn't return scalar. Only those are supported.\n", tname); @@ -6423,7 +6536,7 @@ int btf_prepare_func_args(struct bpf_verifier_env *env, int subprog, t = btf_type_by_id(btf, args[i].type); while (btf_type_is_modifier(t)) t = btf_type_by_id(btf, t->type); - if (btf_type_is_int(t) || btf_type_is_enum(t)) { + if (btf_type_is_int(t) || btf_is_any_enum(t)) { reg->type = SCALAR_VALUE; continue; } @@ -7335,6 +7448,7 @@ int __bpf_core_types_are_compat(const struct btf *local_btf, __u32 local_id, case BTF_KIND_UNION: case BTF_KIND_ENUM: case BTF_KIND_FWD: + case BTF_KIND_ENUM64: return 1; case BTF_KIND_INT: /* just reject deprecated bitfield-like integers; all other @@ -7387,10 +7501,10 @@ int __bpf_core_types_are_compat(const struct btf *local_btf, __u32 local_id, * field-based relocations. This function assumes that root types were already * checked for name match. Beyond that initial root-level name check, names * are completely ignored. Compatibility rules are as follows: - * - any two STRUCTs/UNIONs/FWDs/ENUMs/INTs are considered compatible, but + * - any two STRUCTs/UNIONs/FWDs/ENUMs/INTs/ENUM64s are considered compatible, but * kind should match for local and target types (i.e., STRUCT is not * compatible with UNION); - * - for ENUMs, the size is ignored; + * - for ENUMs/ENUM64s, the size is ignored; * - for INT, size and signedness are ignored; * - for ARRAY, dimensionality is ignored, element types are checked for * compatibility recursively; diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c index aedac2ac02b9..2d2872682278 100644 --- a/kernel/bpf/verifier.c +++ b/kernel/bpf/verifier.c @@ -10901,7 +10901,7 @@ static int check_btf_func(struct bpf_verifier_env *env, goto err_free; ret_type = btf_type_skip_modifiers(btf, func_proto->type, NULL); scalar_return = - btf_type_is_small_int(ret_type) || btf_type_is_enum(ret_type); + btf_type_is_small_int(ret_type) || btf_is_any_enum(ret_type); if (i && !scalar_return && env->subprog_info[i].has_ld_abs) { verbose(env, "LD_ABS is only allowed in functions that return 'int'.\n"); goto err_free; diff --git a/tools/include/uapi/linux/btf.h b/tools/include/uapi/linux/btf.h index a9162a6c0284..ec1798b6d3ff 100644 --- a/tools/include/uapi/linux/btf.h +++ b/tools/include/uapi/linux/btf.h @@ -36,10 +36,10 @@ struct btf_type { * bits 24-28: kind (e.g. int, ptr, array...etc) * bits 29-30: unused * bit 31: kind_flag, currently used by - * struct, union and fwd + * struct, union, enum, fwd and enum64 */ __u32 info; - /* "size" is used by INT, ENUM, STRUCT, UNION and DATASEC. + /* "size" is used by INT, ENUM, STRUCT, UNION, DATASEC and ENUM64. * "size" tells the size of the type it is describing. * * "type" is used by PTR, TYPEDEF, VOLATILE, CONST, RESTRICT, @@ -63,7 +63,7 @@ enum { BTF_KIND_ARRAY = 3, /* Array */ BTF_KIND_STRUCT = 4, /* Struct */ BTF_KIND_UNION = 5, /* Union */ - BTF_KIND_ENUM = 6, /* Enumeration */ + BTF_KIND_ENUM = 6, /* Enumeration up to 32-bit values */ BTF_KIND_FWD = 7, /* Forward */ BTF_KIND_TYPEDEF = 8, /* Typedef */ BTF_KIND_VOLATILE = 9, /* Volatile */ @@ -76,6 +76,7 @@ enum { BTF_KIND_FLOAT = 16, /* Floating point */ BTF_KIND_DECL_TAG = 17, /* Decl Tag */ BTF_KIND_TYPE_TAG = 18, /* Type Tag */ + BTF_KIND_ENUM64 = 19, /* Enumeration up to 64-bit values */ NR_BTF_KINDS, BTF_KIND_MAX = NR_BTF_KINDS - 1, @@ -186,4 +187,14 @@ struct btf_decl_tag { __s32 component_idx; }; +/* BTF_KIND_ENUM64 is followed by multiple "struct btf_enum64". + * The exact number of btf_enum64 is stored in the vlen (of the + * info in "struct btf_type"). + */ +struct btf_enum64 { + __u32 name_off; + __u32 val_lo32; + __u32 val_hi32; +}; + #endif /* _UAPI__LINUX_BTF_H__ */