From mboxrd@z Thu Jan 1 00:00:00 1970 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=-6.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS autolearn=no 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 F23A0C433E6 for ; Fri, 28 Aug 2020 13:46:50 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D38DF207DF for ; Fri, 28 Aug 2020 13:46:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726571AbgH1Nqn (ORCPT ); Fri, 28 Aug 2020 09:46:43 -0400 Received: from foss.arm.com ([217.140.110.172]:49632 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729482AbgH1No0 (ORCPT ); Fri, 28 Aug 2020 09:44:26 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 91FD81FB; Fri, 28 Aug 2020 06:31:52 -0700 (PDT) Received: from C02TD0UTHF1T.local (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 795CC3F66B; Fri, 28 Aug 2020 06:31:49 -0700 (PDT) Date: Fri, 28 Aug 2020 14:31:31 +0100 From: Mark Rutland To: Masami Hiramatsu Cc: linux-kernel@vger.kernel.org, Peter Zijlstra , Eddy_Wu@trendmicro.com, x86@kernel.org, davem@davemloft.net, rostedt@goodmis.org, naveen.n.rao@linux.ibm.com, anil.s.keshavamurthy@intel.com, linux-arch@vger.kernel.org, cameron@moodycamel.com, oleg@redhat.com, will@kernel.org, paulmck@kernel.org Subject: Re: [PATCH v4 04/23] arm64: kprobes: Use generic kretprobe trampoline handler Message-ID: <20200828133131.GA71981@C02TD0UTHF1T.local> References: <159861759775.992023.12553306821235086809.stgit@devnote2> <159861764221.992023.10214437014901668680.stgit@devnote2> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <159861764221.992023.10214437014901668680.stgit@devnote2> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, On Fri, Aug 28, 2020 at 09:27:22PM +0900, Masami Hiramatsu wrote: > Use the generic kretprobe trampoline handler, and use the > kernel_stack_pointer(regs) for framepointer verification. > > Signed-off-by: Masami Hiramatsu > --- > arch/arm64/kernel/probes/kprobes.c | 78 +----------------------------------- > 1 file changed, 3 insertions(+), 75 deletions(-) > + return (void *)kretprobe_trampoline_handler(regs, &kretprobe_trampoline, > + (void *)kernel_stack_pointer(regs)); > } > > void __kprobes arch_prepare_kretprobe(struct kretprobe_instance *ri, > struct pt_regs *regs) > { > ri->ret_addr = (kprobe_opcode_t *)regs->regs[30]; > + ri->fp = (void *)kernel_stack_pointer(regs); This is probably a nomenclature problem, but what exactly is kretprobe_instance::fp used for? I ask because arm64's frame pointer lives in x29 (and is not necessarily the same as the stack pointer at function boundaries), so the naming is potentially misleading and possibly worth a comment or rename. Thanks, Mark.