From patchwork Thu May 6 03:44:58 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexei Starovoitov X-Patchwork-Id: 12241583 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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, 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 4727AC43460 for ; Thu, 6 May 2021 03:45:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 28F12611CB for ; Thu, 6 May 2021 03:45:26 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230198AbhEFDqW (ORCPT ); Wed, 5 May 2021 23:46:22 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:45436 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230078AbhEFDqT (ORCPT ); Wed, 5 May 2021 23:46:19 -0400 Received: from mail-pf1-x435.google.com (mail-pf1-x435.google.com [IPv6:2607:f8b0:4864:20::435]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 158D9C061574 for ; Wed, 5 May 2021 20:45:22 -0700 (PDT) Received: by mail-pf1-x435.google.com with SMTP id v191so4113338pfc.8 for ; Wed, 05 May 2021 20:45:22 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=v5dOt2ICV2YMuXw6Q5/9wTf1h3zkV9EcQfwC4XhpWXk=; b=UrkITXY4BE0w7Lvxr/GYnlmLv4e6BtEY0rSjai3OAP2nPQxcGFsOkF+6yRARjMLIND 1cYFN2Q++u/u/3UaIYaXs+9YJYZ7CE7aeRfT7FbhkQNvkA0wffjkk0NiyXQlYOLNSdF2 FYvirOZTx6D1XLynPPe0dCXyw29eCUH48DrsQ+43Yebqo4Su5gK+lKu8DUdvqi8HNi0R ThtrcatDBdFD663HPLQT6Eotu5MUsjuBG+viH0qJwnicefdkfYlA2XxKEI2oQF8FEsCd q+aDhca9zANxF5iAAQSJ4ax3ZcSc12ho946lvIbCSIi1996/7TaGbL1fJS8u1wIiMcWe BQEQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=v5dOt2ICV2YMuXw6Q5/9wTf1h3zkV9EcQfwC4XhpWXk=; b=i37jXeoQbDi1wZw7P2jyNyblKTZJoPX3U3Q+kZwB3Vdm3hdgL0wxESNmY4IFFpbP2n gcx0y6UXTOMhzjKJ0mQlXd3Mmc0pdjFHe4u4b+BcllKdec1tP065RxCB7qW1qgPZpqve Nkc6Ne9/MVSO8SJ+DQ9xdERG+NN5SJIE/rysbU5cNgrHIQJrRMosSdulvctQKESkq6bP gcpL99nsDxyPNsGWp48YsoAyF2NzSFClvSVa7Js5ssjYVAqNPlgmS0E9bdNWLDv6b1+I FVuKDfLEzRM5Uiw4JKiWOGd7tB07CkAIFhIAr58zYcGd0ZRl9pN8uYNtpl/hRO5f6ggZ bdMg== X-Gm-Message-State: AOAM5304IutcY5fcQufq8n46EYgwxB73fpuGurz56S+z4fp0dr+mWylS kocfgfBCMkW4JMqj/r/X0Vs= X-Google-Smtp-Source: ABdhPJzYZFwsdm1M/+Sdp5WkaUKrJ/H9Yu5x1BqyUca3qMX4iS+31mX/shaLDVb8IVtnZjO0hW80ig== X-Received: by 2002:a63:1a47:: with SMTP id a7mr2106760pgm.437.1620272721663; Wed, 05 May 2021 20:45:21 -0700 (PDT) Received: from ast-mbp.thefacebook.com ([163.114.132.7]) by smtp.gmail.com with ESMTPSA id r22sm578997pgr.1.2021.05.05.20.45.20 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Wed, 05 May 2021 20:45:21 -0700 (PDT) From: Alexei Starovoitov To: davem@davemloft.net Cc: daniel@iogearbox.net, andrii@kernel.org, john.fastabend@gmail.com, bpf@vger.kernel.org, kernel-team@fb.com Subject: [PATCH v3 bpf-next 10/17] bpf: Add bpf_btf_find_by_name_kind() helper. Date: Wed, 5 May 2021 20:44:58 -0700 Message-Id: <20210506034505.25979-11-alexei.starovoitov@gmail.com> X-Mailer: git-send-email 2.13.5 In-Reply-To: <20210506034505.25979-1-alexei.starovoitov@gmail.com> References: <20210506034505.25979-1-alexei.starovoitov@gmail.com> Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net From: Alexei Starovoitov Add new helper: long bpf_btf_find_by_name_kind(char *name, int name_sz, u32 kind, int flags) Description Find BTF type with given name and kind in vmlinux BTF or in module's BTFs. Return Returns btf_id and btf_obj_fd in lower and upper 32 bits. It will be used by loader program to find btf_id to attach the program to and to find btf_ids of ksyms. Signed-off-by: Alexei Starovoitov --- include/linux/bpf.h | 1 + include/uapi/linux/bpf.h | 7 ++++ kernel/bpf/btf.c | 62 ++++++++++++++++++++++++++++++++++ kernel/bpf/syscall.c | 2 ++ tools/include/uapi/linux/bpf.h | 7 ++++ 5 files changed, 79 insertions(+) diff --git a/include/linux/bpf.h b/include/linux/bpf.h index 7fd53380c981..9dc44ba97584 100644 --- a/include/linux/bpf.h +++ b/include/linux/bpf.h @@ -1974,6 +1974,7 @@ extern const struct bpf_func_proto bpf_get_socket_ptr_cookie_proto; extern const struct bpf_func_proto bpf_task_storage_get_proto; extern const struct bpf_func_proto bpf_task_storage_delete_proto; extern const struct bpf_func_proto bpf_for_each_map_elem_proto; +extern const struct bpf_func_proto bpf_btf_find_by_name_kind_proto; const struct bpf_func_proto *bpf_tracing_func_proto( enum bpf_func_id func_id, const struct bpf_prog *prog); diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h index de58a714ed36..3cc07351c1cf 100644 --- a/include/uapi/linux/bpf.h +++ b/include/uapi/linux/bpf.h @@ -4748,6 +4748,12 @@ union bpf_attr { * Execute bpf syscall with given arguments. * Return * A syscall result. + * + * long bpf_btf_find_by_name_kind(char *name, int name_sz, u32 kind, int flags) + * Description + * Find BTF type with given name and kind in vmlinux BTF or in module's BTFs. + * Return + * Returns btf_id and btf_obj_fd in lower and upper 32 bits. */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -4917,6 +4923,7 @@ union bpf_attr { FN(for_each_map_elem), \ FN(snprintf), \ FN(sys_bpf), \ + FN(btf_find_by_name_kind), \ /* */ /* integer value in 'imm' field of BPF_CALL instruction selects which helper diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c index fbf6c06a9d62..85716327c375 100644 --- a/kernel/bpf/btf.c +++ b/kernel/bpf/btf.c @@ -6085,3 +6085,65 @@ struct module *btf_try_get_module(const struct btf *btf) return res; } + +BPF_CALL_4(bpf_btf_find_by_name_kind, char *, name, int, name_sz, u32, kind, int, flags) +{ + struct btf *btf; + long ret; + + if (flags) + return -EINVAL; + + if (name_sz <= 1 || name[name_sz - 1]) + return -EINVAL; + + btf = bpf_get_btf_vmlinux(); + if (IS_ERR(btf)) + return PTR_ERR(btf); + + ret = btf_find_by_name_kind(btf, name, kind); + /* ret is never zero, since btf_find_by_name_kind returns + * positive btf_id or negative error. + */ + if (ret < 0) { + struct btf *mod_btf; + int id; + + /* If name is not found in vmlinux's BTF then search in module's BTFs */ + spin_lock_bh(&btf_idr_lock); + idr_for_each_entry(&btf_idr, mod_btf, id) { + if (!btf_is_module(mod_btf)) + continue; + /* linear search could be slow hence unlock/lock + * the IDR to avoiding holding it for too long + */ + btf_get(mod_btf); + spin_unlock_bh(&btf_idr_lock); + ret = btf_find_by_name_kind(mod_btf, name, kind); + if (ret > 0) { + int btf_obj_fd; + + btf_obj_fd = __btf_new_fd(mod_btf); + if (btf_obj_fd < 0) { + btf_put(mod_btf); + return btf_obj_fd; + } + return ret | (((u64)btf_obj_fd) << 32); + } + spin_lock_bh(&btf_idr_lock); + btf_put(mod_btf); + } + spin_unlock_bh(&btf_idr_lock); + } + return ret; +} + +const struct bpf_func_proto bpf_btf_find_by_name_kind_proto = { + .func = bpf_btf_find_by_name_kind, + .gpl_only = false, + .ret_type = RET_INTEGER, + .arg1_type = ARG_PTR_TO_MEM, + .arg2_type = ARG_CONST_SIZE, + .arg3_type = ARG_ANYTHING, + .arg4_type = ARG_ANYTHING, +}; diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c index da7dc2406470..f93ff2ebf96d 100644 --- a/kernel/bpf/syscall.c +++ b/kernel/bpf/syscall.c @@ -4584,6 +4584,8 @@ syscall_prog_func_proto(enum bpf_func_id func_id, const struct bpf_prog *prog) switch (func_id) { case BPF_FUNC_sys_bpf: return &bpf_sys_bpf_proto; + case BPF_FUNC_btf_find_by_name_kind: + return &bpf_btf_find_by_name_kind_proto; default: return tracing_prog_func_proto(func_id, prog); } diff --git a/tools/include/uapi/linux/bpf.h b/tools/include/uapi/linux/bpf.h index 6c8e178d8ffa..8a892231a1ae 100644 --- a/tools/include/uapi/linux/bpf.h +++ b/tools/include/uapi/linux/bpf.h @@ -4748,6 +4748,12 @@ union bpf_attr { * Execute bpf syscall with given arguments. * Return * A syscall result. + * + * long bpf_btf_find_by_name_kind(char *name, int name_sz, u32 kind, int flags) + * Description + * Find BTF type with given name and kind in vmlinux BTF or in module's BTFs. + * Return + * Returns btf_id and btf_obj_fd in lower and upper 32 bits. */ #define __BPF_FUNC_MAPPER(FN) \ FN(unspec), \ @@ -4917,6 +4923,7 @@ union bpf_attr { FN(for_each_map_elem), \ FN(snprintf), \ FN(sys_bpf), \ + FN(btf_find_by_name_kind), \ /* */ /* integer value in 'imm' field of BPF_CALL instruction selects which helper