From patchwork Mon Jul 18 00:14:01 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Song Liu X-Patchwork-Id: 12920678 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 694CAC433EF for ; Mon, 18 Jul 2022 00:14:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231370AbiGRAOa convert rfc822-to-8bit (ORCPT ); Sun, 17 Jul 2022 20:14:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54766 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229621AbiGRAOa (ORCPT ); Sun, 17 Jul 2022 20:14:30 -0400 Received: from mx0a-00082601.pphosted.com (mx0b-00082601.pphosted.com [67.231.153.30]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id A025B7652 for ; Sun, 17 Jul 2022 17:14:29 -0700 (PDT) Received: from pps.filterd (m0001303.ppops.net [127.0.0.1]) by m0001303.ppops.net (8.17.1.5/8.17.1.5) with ESMTP id 26HIHZdb002308 for ; Sun, 17 Jul 2022 17:14:29 -0700 Received: from mail.thefacebook.com ([163.114.132.120]) by m0001303.ppops.net (PPS) with ESMTPS id 3hbxbg55ev-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Sun, 17 Jul 2022 17:14:28 -0700 Received: from twshared10560.18.frc3.facebook.com (2620:10d:c085:108::4) 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; Sun, 17 Jul 2022 17:14:27 -0700 Received: by devbig932.frc1.facebook.com (Postfix, from userid 4523) id 7B084A495CE3; Sun, 17 Jul 2022 17:14:17 -0700 (PDT) From: Song Liu To: , , CC: , , , , Song Liu Subject: [PATCH v3 bpf-next 0/4] ftrace: host klp and bpf trampoline together Date: Sun, 17 Jul 2022 17:14:01 -0700 Message-ID: <20220718001405.2236811-1-song@kernel.org> X-Mailer: git-send-email 2.30.2 X-FB-Internal: Safe X-Proofpoint-ORIG-GUID: GI-GBX4I9q1cNxpVJgqwzZ0X5u3l1ooG X-Proofpoint-GUID: GI-GBX4I9q1cNxpVJgqwzZ0X5u3l1ooG X-Proofpoint-UnRewURL: 0 URL was un-rewritten MIME-Version: 1.0 X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.883,Hydra:6.0.517,FMLib:17.11.122.1 definitions=2022-07-17_17,2022-07-15_01,2022-06-22_01 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net Changes v2 => v3: 1. Major rewrite after discussions with Steven Rostedt. [1] 2. Remove SHARE_IPMODIFY flag from ftrace code. Instead use the callback function to communicate this information. (Steven) 3. Add cleanup_direct_functions_after_ipmodify() to clear SHARE_IPMODIFY on the DIRECT ops when the IPMODIFY ops is removed. Changes v1 => v2: 1. Fix build errors for different config. (kernel test robot) Kernel Live Patch (livepatch, or klp) and bpf trampoline are important features for modern systems. This set allows the two to work on the same kernel function as the same time. live patch uses ftrace with IPMODIFY, while bpf trampoline use direct ftrace. Existing policy does not allow the two to attach to the same kernel function. This is changed by fine tuning ftrace IPMODIFY policy, and allows one IPMODIFY ftrace_ops and one DIRECT ftrace_ops on the same kernel function at the same time. Please see patch 2 and 4 for more details. Note that, one of the constraint here is to let bpf trampoline use direct call when it is not working on the same function as live patch. This is achieved by allowing ftrace code to ask bpf trampoline to make changes. [1] https://lore.kernel.org/all/20220602193706.2607681-2-song@kernel.org/ Jiri Olsa (1): bpf, x64: Allow to use caller address from stack Song Liu (3): ftrace: add modify_ftrace_direct_multi_nolock ftrace: allow IPMODIFY and DIRECT ops on the same function bpf: support bpf_trampoline on functions with IPMODIFY (e.g. livepatch) arch/x86/net/bpf_jit_comp.c | 13 +- include/linux/bpf.h | 13 ++ include/linux/ftrace.h | 43 ++++++ kernel/bpf/trampoline.c | 158 +++++++++++++++++--- kernel/trace/ftrace.c | 288 +++++++++++++++++++++++++++++++----- 5 files changed, 455 insertions(+), 60 deletions(-) --- 2.30.2