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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS 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 6617CC43219 for ; Wed, 1 May 2019 19:00:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3E2A320866 for ; Wed, 1 May 2019 19:00:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726224AbfEATAa (ORCPT ); Wed, 1 May 2019 15:00:30 -0400 Received: from mail.kernel.org ([198.145.29.99]:33952 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726019AbfEATA3 (ORCPT ); Wed, 1 May 2019 15:00:29 -0400 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 C985E20675; Wed, 1 May 2019 19:00:26 +0000 (UTC) Date: Wed, 1 May 2019 15:00:25 -0400 From: Steven Rostedt To: Peter Zijlstra Cc: Linus Torvalds , Andy Lutomirski , Nicolai Stange , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H. Peter Anvin" , the arch/x86 maintainers , Josh Poimboeuf , Jiri Kosina , Miroslav Benes , Petr Mladek , Joe Lawrence , Shuah Khan , Konrad Rzeszutek Wilk , Tim Chen , Sebastian Andrzej Siewior , Mimi Zohar , Juergen Gross , Nick Desaulniers , Nayna Jain , Masahiro Yamada , Joerg Roedel , Linux List Kernel Mailing , live-patching@vger.kernel.org, "open list:KERNEL SELFTEST FRAMEWORK" Subject: Re: [RFC][PATCH v3] ftrace/x86_64: Emulate call function while updating in breakpoint handler Message-ID: <20190501150025.40169f1d@gandalf.local.home> In-Reply-To: <20190501185726.GR7905@worktop.programming.kicks-ass.net> References: <20190501113238.0ab3f9dd@gandalf.local.home> <20190501185726.GR7905@worktop.programming.kicks-ass.net> 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, 1 May 2019 20:57:26 +0200 Peter Zijlstra wrote: > On Wed, May 01, 2019 at 11:01:07AM -0700, Linus Torvalds wrote: > > This looks sane to me, although I'm surprised that we didn't already > > have an annotation for the nonstandard stack frame for asm files. That > > probably would be cleaner in a separate commit, but I guess it doesn't > > matter. > > > > Anyway, I'm willing to consider the entry code version if it looks a > > _lot_ simpler than this (so I'd like to see them side-by-side), but > > it's not like this looks all that complicated to me either. > > So I posted one earlier today: > > https://lkml.kernel.org/r/20190501131117.GW2623@hirez.programming.kicks-ass.net > > it's about a 1/3rd the number of lines and has 32bit support. It also > provides all the bits required to implement static_call(). That's the patch I started with. > > That is; I think I'm firmly in favour of the entry variant -- provided > it actually works of course. And it works. I ran it through tools/testing/selftests/ftrace/ftracetest and it passed as good as without that patch. I haven't ran it through my full test suite. I can do that and see how it makes out. -- Steve