From patchwork Thu Apr 21 00:38:58 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexander Lobakin X-Patchwork-Id: 12820958 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 29322C433EF for ; Thu, 21 Apr 2022 00:39:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1383469AbiDUAl5 (ORCPT ); Wed, 20 Apr 2022 20:41:57 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37472 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1383457AbiDUAlz (ORCPT ); Wed, 20 Apr 2022 20:41:55 -0400 Received: from mail-4322.protonmail.ch (mail-4322.protonmail.ch [185.70.43.22]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B39B0220ED; Wed, 20 Apr 2022 17:39:07 -0700 (PDT) Date: Thu, 21 Apr 2022 00:38:58 +0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=pm.me; s=protonmail2; t=1650501546; bh=h36ggskq9XGdjBzPQnssVWN6Wf4iatLNUirRoRiZBiw=; h=Date:To:From:Cc:Reply-To:Subject:Message-ID:In-Reply-To: References:Feedback-ID:From:To:Cc:Date:Subject:Reply-To: Feedback-ID:Message-ID; b=OPefelKWg3a3dc5CM+Llww0E8ejWJF79yrwH+/bMFAp0Vdv6ZMhndPKiLLkJhzfnc LvMJixUnblLiq/pjz3DQf+QJ/KQ/eUxdr242SV+sx5UKT9QwIXJekNU/04JIuPORn8 pa4tlEnFh2HIfI9h66mm4nrIQyX/XDOXaZ8qvB8r7YrjmvG5Kn0DJQzss47Zuj4buw Ve++O26D0XYWZ7AKDswIgatuWGqdnJGtuQJI8pXviQVdQJD97FlbWKR0OpX4Lvkjkc UHUm9ZGCjpyp6rWoew0zGtTUIlhR9rVqh8BbOJRu/FFQrWneE5Cw1fA2NqW4C7gBSi wjtnfMp8ViNAg== To: Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko From: Alexander Lobakin Cc: Alexander Lobakin , Maciej Fijalkowski , Song Liu , Kumar Kartikeya Dwivedi , bpf@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Reply-To: Alexander Lobakin Subject: [PATCH v2 bpf 02/11] bpftool: define a local bpf_perf_link to fix accessing its fields Message-ID: <20220421003152.339542-3-alobakin@pm.me> In-Reply-To: <20220421003152.339542-1-alobakin@pm.me> References: <20220421003152.339542-1-alobakin@pm.me> Feedback-ID: 22809121:user:proton MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net When building bpftool with !CONFIG_PERF_EVENTS: skeleton/pid_iter.bpf.c:47:14: error: incomplete definition of type 'struct bpf_perf_link' perf_link = container_of(link, struct bpf_perf_link, link); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ tools/bpf/bpftool/bootstrap/libbpf/include/bpf/bpf_helpers.h:74:22: note: expanded from macro 'container_of' ((type *)(__mptr - offsetof(type, member))); \ ^~~~~~~~~~~~~~~~~~~~~~ tools/bpf/bpftool/bootstrap/libbpf/include/bpf/bpf_helpers.h:68:60: note: expanded from macro 'offsetof' #define offsetof(TYPE, MEMBER) ((unsigned long)&((TYPE *)0)->MEMBER) ~~~~~~~~~~~^ skeleton/pid_iter.bpf.c:44:9: note: forward declaration of 'struct bpf_perf_link' struct bpf_perf_link *perf_link; ^ &bpf_perf_link is being defined and used only under the ifdef. Define struct bpf_perf_link___local with the `preserve_access_index` attribute inside the pid_iter BPF prog to allow compiling on any configs. CO-RE will substitute it with the real struct bpf_perf_link accesses later on. container_of() is not CO-REd, but it is a noop for bpf_perf_link <-> bpf_link and the local copy is a full mirror of the original structure. Fixes: cbdaf71f7e65 ("bpftool: Add bpf_cookie to link output") Suggested-by: Andrii Nakryiko Signed-off-by: Alexander Lobakin --- tools/bpf/bpftool/skeleton/pid_iter.bpf.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) -- 2.36.0 diff --git a/tools/bpf/bpftool/skeleton/pid_iter.bpf.c b/tools/bpf/bpftool/skeleton/pid_iter.bpf.c index e2af8e5fb29e..3a4c4f7d83d8 100644 --- a/tools/bpf/bpftool/skeleton/pid_iter.bpf.c +++ b/tools/bpf/bpftool/skeleton/pid_iter.bpf.c @@ -15,6 +15,11 @@ enum bpf_obj_type { BPF_OBJ_BTF, }; +struct bpf_perf_link___local { + struct bpf_link link; + struct file *perf_file; +} __attribute__((preserve_access_index)); + struct perf_event___local { u64 bpf_cookie; } __attribute__((preserve_access_index)); @@ -45,10 +50,10 @@ static __always_inline __u32 get_obj_id(void *ent, enum bpf_obj_type type) /* could be used only with BPF_LINK_TYPE_PERF_EVENT links */ static __u64 get_bpf_cookie(struct bpf_link *link) { + struct bpf_perf_link___local *perf_link; struct perf_event___local *event; - struct bpf_perf_link *perf_link; - perf_link = container_of(link, struct bpf_perf_link, link); + perf_link = container_of(link, struct bpf_perf_link___local, link); event = BPF_CORE_READ(perf_link, perf_file, private_data); return BPF_CORE_READ(event, bpf_cookie); }