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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 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 0D36DC3405E for ; Wed, 19 Feb 2020 17:05:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id E2FDE24656 for ; Wed, 19 Feb 2020 17:05:23 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726791AbgBSRFW (ORCPT ); Wed, 19 Feb 2020 12:05:22 -0500 Received: from mail.kernel.org ([198.145.29.99]:39918 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726514AbgBSRFW (ORCPT ); Wed, 19 Feb 2020 12:05:22 -0500 Received: from gandalf.local.home (cpe-66-24-58-225.stny.res.rr.com [66.24.58.225]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 7F9AF2464E; Wed, 19 Feb 2020 17:05:20 +0000 (UTC) Date: Wed, 19 Feb 2020 12:05:19 -0500 From: Steven Rostedt To: "Paul E. McKenney" Cc: Peter Zijlstra , linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, mingo@kernel.org, joel@joelfernandes.org, gregkh@linuxfoundation.org, gustavo@embeddedor.com, tglx@linutronix.de, josh@joshtriplett.org, mathieu.desnoyers@efficios.com, jiangshanlai@gmail.com, luto@kernel.org, tony.luck@intel.com, frederic@kernel.org, dan.carpenter@oracle.com, mhiramat@kernel.org Subject: Re: [PATCH v3 04/22] x86/doublefault: Make memmove() notrace/NOKPROBE Message-ID: <20200219120519.22ba89c4@gandalf.local.home> In-Reply-To: <20200219162747.GX2935@paulmck-ThinkPad-P72> References: <20200219144724.800607165@infradead.org> <20200219150744.604459293@infradead.org> <20200219103614.2299ff61@gandalf.local.home> <20200219154031.GE18400@hirez.programming.kicks-ass.net> <20200219155715.GD14946@hirez.programming.kicks-ass.net> <20200219160442.GE14946@hirez.programming.kicks-ass.net> <20200219111228.44c2999b@gandalf.local.home> <20200219162747.GX2935@paulmck-ThinkPad-P72> X-Mailer: Claws Mail 3.17.3 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 19 Feb 2020 08:27:47 -0800 "Paul E. McKenney" wrote: > > Or, we could just cut and paste the current memmove and make a notrace > > version too. Then we don't need to worry bout bugs like this. > > OK, I will bite... > > Can we just make the core be an inline function and make a notrace and > a trace caller? Possibly going one step further and having one call > the other? (Presumably the traceable version invoking the notrace > version, but it has been one good long time since I have looked at > function preambles.) Sure. Looking at the implementation (which is big and ugly), we could have a static always_inline void __memmove(...) { [..] } __visible void *memmove(...) { return __memmove(...); } __visible notrace void *memmove_notrace(...) { return __memmove(...); } -- Steve