From patchwork Wed Sep 15 03:37:51 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Hou Tao X-Patchwork-Id: 512818 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=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, 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 8E90BC433EF for ; Wed, 15 Sep 2021 03:24:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 76EB761157 for ; Wed, 15 Sep 2021 03:24:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236165AbhIODZS (ORCPT ); Tue, 14 Sep 2021 23:25:18 -0400 Received: from szxga01-in.huawei.com ([45.249.212.187]:19977 "EHLO szxga01-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236078AbhIODZR (ORCPT ); Tue, 14 Sep 2021 23:25:17 -0400 Received: from dggemv703-chm.china.huawei.com (unknown [172.30.72.53]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4H8QSR4d1RzbmVT; Wed, 15 Sep 2021 11:19:51 +0800 (CST) Received: from dggpeml500025.china.huawei.com (7.185.36.35) by dggemv703-chm.china.huawei.com (10.3.19.46) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.8; Wed, 15 Sep 2021 11:23:51 +0800 Received: from huawei.com (10.175.124.27) by dggpeml500025.china.huawei.com (7.185.36.35) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.8; Wed, 15 Sep 2021 11:23:51 +0800 From: Hou Tao To: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko , Martin KaFai Lau CC: , , Subject: [RFC PATCH bpf-next 1/3] bpf: add dummy BPF STRUCT_OPS for test purpose Date: Wed, 15 Sep 2021 11:37:51 +0800 Message-ID: <20210915033753.1201597-2-houtao1@huawei.com> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20210915033753.1201597-1-houtao1@huawei.com> References: <20210915033753.1201597-1-houtao1@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.175.124.27] X-ClientProxiedBy: dggems703-chm.china.huawei.com (10.3.19.180) To dggpeml500025.china.huawei.com (7.185.36.35) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Currently the test of BPF STRUCT_OPS depends on the specific bpf implementation of tcp_congestion_ops, and it can not cover all basic functionalities (e.g, return value handling), so introduce a dummy BPF STRUCT_OPS for test purpose. Dummy BPF STRUCT_OPS may not being needed for release kernel, so adding a kconfig option BPF_DUMMY_STRUCT_OPS to enable it separatedly. Signed-off-by: Hou Tao --- include/linux/bpf_dummy_ops.h | 28 +++++ kernel/bpf/Kconfig | 7 ++ kernel/bpf/Makefile | 2 + kernel/bpf/bpf_dummy_struct_ops.c | 173 ++++++++++++++++++++++++++++++ kernel/bpf/bpf_struct_ops_types.h | 4 + 5 files changed, 214 insertions(+) create mode 100644 include/linux/bpf_dummy_ops.h create mode 100644 kernel/bpf/bpf_dummy_struct_ops.c diff --git a/include/linux/bpf_dummy_ops.h b/include/linux/bpf_dummy_ops.h new file mode 100644 index 000000000000..b2aad3e6e2fe --- /dev/null +++ b/include/linux/bpf_dummy_ops.h @@ -0,0 +1,28 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ +/* + * Copyright (C) 2021. Huawei Technologies Co., Ltd + */ +#ifndef _BPF_DUMMY_OPS_H +#define _BPF_DUMMY_OPS_H + +#ifdef CONFIG_BPF_DUMMY_STRUCT_OPS +#include + +struct bpf_dummy_ops_state { + int val; +}; + +struct bpf_dummy_ops { + int (*init)(struct bpf_dummy_ops_state *state); + struct module *owner; +}; + +extern struct bpf_dummy_ops *bpf_get_dummy_ops(void); +extern void bpf_put_dummy_ops(struct bpf_dummy_ops *ops); +#else +struct bpf_dummy_ops {}； +static inline struct bpf_dummy_ops *bpf_get_dummy_ops(void) { return NULL; } +static inline void bpf_put_dummy_ops(struct bpf_dummy_ops *ops) {} +#endif + +#endif diff --git a/kernel/bpf/Kconfig b/kernel/bpf/Kconfig index a82d6de86522..4a11eca42791 100644 --- a/kernel/bpf/Kconfig +++ b/kernel/bpf/Kconfig @@ -86,4 +86,11 @@ config BPF_LSM If you are unsure how to answer this question, answer N. +config BPF_DUMMY_STRUCT_OPS + bool "Enable dummy struct ops" + depends on BPF_SYSCALL && BPF_JIT + help + Enables dummy struct ops to test the basic functionalities of + BPF STRUCT_OPS. + endmenu # "BPF subsystem" diff --git a/kernel/bpf/Makefile b/kernel/bpf/Makefile index 7f33098ca63f..17e2bb59cceb 100644 --- a/kernel/bpf/Makefile +++ b/kernel/bpf/Makefile @@ -33,6 +33,8 @@ obj-$(CONFIG_DEBUG_INFO_BTF) += sysfs_btf.o endif ifeq ($(CONFIG_BPF_JIT),y) obj-$(CONFIG_BPF_SYSCALL) += bpf_struct_ops.o +obj-$(CONFIG_BPF_SYSCALL) += bpf_dummy_struct_ops.o obj-${CONFIG_BPF_LSM} += bpf_lsm.o endif +obj-$(CONFIG_BPF_DUMMY_STRUCT_OPS) += bpf_dummy_struct_ops.o obj-$(CONFIG_BPF_PRELOAD) += preload/ diff --git a/kernel/bpf/bpf_dummy_struct_ops.c b/kernel/bpf/bpf_dummy_struct_ops.c new file mode 100644 index 000000000000..f76c4a3733f0 --- /dev/null +++ b/kernel/bpf/bpf_dummy_struct_ops.c @@ -0,0 +1,173 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Copyright (C) 2021. Huawei Technologies Co., Ltd + */ +#include +#include +#include +#include +#include +#include + +static struct bpf_dummy_ops *bpf_dummy_ops_singletion; +static DEFINE_SPINLOCK(bpf_dummy_ops_lock); + +static const struct btf_type *dummy_ops_state; + +struct bpf_dummy_ops *bpf_get_dummy_ops(void) +{ + struct bpf_dummy_ops *ops; + + spin_lock(&bpf_dummy_ops_lock); + ops = bpf_dummy_ops_singletion; + if (ops && !bpf_try_module_get(ops, ops->owner)) + ops = NULL; + spin_unlock(&bpf_dummy_ops_lock); + + return ops ? ops : ERR_PTR(-ENXIO); +} +EXPORT_SYMBOL_GPL(bpf_get_dummy_ops); + +void bpf_put_dummy_ops(struct bpf_dummy_ops *ops) +{ + bpf_module_put(ops, ops->owner); +} +EXPORT_SYMBOL_GPL(bpf_put_dummy_ops); + +static int bpf_dummy_init(struct btf *btf) +{ + s32 type_id; + + type_id = btf_find_by_name_kind(btf, "bpf_dummy_ops_state", + BTF_KIND_STRUCT); + if (type_id < 0) + return -EINVAL; + + dummy_ops_state = btf_type_by_id(btf, type_id); + + return 0; +} + +static const struct bpf_func_proto * +bpf_dummy_ops_get_func_proto(enum bpf_func_id func_id, + const struct bpf_prog *prog) +{ + switch (func_id) { + case BPF_FUNC_map_lookup_elem: + return &bpf_map_lookup_elem_proto; + default: + return NULL; + } +} + +static bool bpf_dummy_ops_is_valid_access(int off, int size, + enum bpf_access_type type, + const struct bpf_prog *prog, + struct bpf_insn_access_aux *info) +{ + /* a common helper ? */ + if (off < 0 || off >= sizeof(__u64) * MAX_BPF_FUNC_ARGS) + return false; + if (type != BPF_READ) + return false; + if (off % size != 0) + return false; + + return btf_ctx_access(off, size, type, prog, info); +} + +static int bpf_dummy_ops_btf_struct_access(struct bpf_verifier_log *log, + const struct btf *btf, + const struct btf_type *t, int off, + int size, enum bpf_access_type atype, + u32 *next_btf_id) +{ + size_t end; + + if (atype == BPF_READ) + return btf_struct_access(log, btf, t, off, size, atype, + next_btf_id); + + if (t != dummy_ops_state) { + bpf_log(log, "only read is supported\n"); + return -EACCES; + } + + switch (off) { + case offsetof(struct bpf_dummy_ops_state, val): + end = offsetofend(struct bpf_dummy_ops_state, val); + break; + default: + bpf_log(log, "no write support to bpf_dummy_ops_state at off %d\n", + off); + return -EACCES; + } + + if (off + size > end) { + bpf_log(log, + "write access at off %d with size %d beyond the member of bpf_dummy_ops_state ended at %zu\n", + off, size, end); + return -EACCES; + } + + return NOT_INIT; +} + +static const struct bpf_verifier_ops bpf_dummy_verifier_ops = { + .get_func_proto = bpf_dummy_ops_get_func_proto, + .is_valid_access = bpf_dummy_ops_is_valid_access, + .btf_struct_access = bpf_dummy_ops_btf_struct_access, +}; + +static int bpf_dummy_check_member(const struct btf_type *t, + const struct btf_member *member) +{ + return 0; +} + + +static int bpf_dummy_init_member(const struct btf_type *t, + const struct btf_member *member, + void *kdata, const void *udata) +{ + return 0; +} + +static int bpf_dummy_reg(void *kdata) +{ + struct bpf_dummy_ops *ops = kdata; + int err = 0; + + spin_lock(&bpf_dummy_ops_lock); + if (!bpf_dummy_ops_singletion) + bpf_dummy_ops_singletion = ops; + else + err = -EEXIST; + spin_unlock(&bpf_dummy_ops_lock); + + return err; +} + +static void bpf_dummy_unreg(void *kdata) +{ + struct bpf_dummy_ops *ops = kdata; + + spin_lock(&bpf_dummy_ops_lock); + if (bpf_dummy_ops_singletion == ops) + bpf_dummy_ops_singletion = NULL; + else + WARN_ON(1); + spin_unlock(&bpf_dummy_ops_lock); +} + +extern struct bpf_struct_ops bpf_bpf_dummy_ops; + +struct bpf_struct_ops bpf_bpf_dummy_ops = { + .verifier_ops = &bpf_dummy_verifier_ops, + .init = bpf_dummy_init, + .init_member = bpf_dummy_init_member, + .check_member = bpf_dummy_check_member, + .reg = bpf_dummy_reg, + .unreg = bpf_dummy_unreg, + .name = "bpf_dummy_ops", +}; diff --git a/kernel/bpf/bpf_struct_ops_types.h b/kernel/bpf/bpf_struct_ops_types.h index 7ec458ead497..6d24c75f4d70 100644 --- a/kernel/bpf/bpf_struct_ops_types.h +++ b/kernel/bpf/bpf_struct_ops_types.h @@ -2,6 +2,10 @@ /* internal file - do not include directly */ #ifdef CONFIG_BPF_JIT +#ifdef CONFIG_BPF_DUMMY_STRUCT_OPS +#include +BPF_STRUCT_OPS_TYPE(bpf_dummy_ops) +#endif #ifdef CONFIG_INET #include BPF_STRUCT_OPS_TYPE(tcp_congestion_ops)