From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751312AbdBXLnE (ORCPT ); Fri, 24 Feb 2017 06:43:04 -0500 Received: from terminus.zytor.com ([65.50.211.136]:56364 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751082AbdBXLm5 (ORCPT ); Fri, 24 Feb 2017 06:42:57 -0500 Subject: Re: [PATCH] x86: Implement __WARN using UD0 To: Borislav Petkov , Ingo Molnar References: <20170223132813.GB6515@twins.programming.kicks-ass.net> <20170223145751.GE6515@twins.programming.kicks-ass.net> <20170224074325.GA4095@gmail.com> <20170224083115.GK6515@twins.programming.kicks-ass.net> <20170224091537.GA18182@gmail.com> <20170224094644.ify3fpzw33o754ra@pd.tnic> Cc: Peter Zijlstra , Arjan van de Ven , Thomas Gleixner , linux-kernel@vger.kernel.org, torvalds@linux-foundation.org, jpoimboe@redhat.com, richard.weinberger@gmail.com, Andrew Morton From: "H. Peter Anvin" Message-ID: <446217f9-147d-17e7-9033-845088f67806@zytor.com> Date: Fri, 24 Feb 2017 01:52:44 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.6.0 MIME-Version: 1.0 In-Reply-To: <20170224094644.ify3fpzw33o754ra@pd.tnic> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02/24/17 01:46, Borislav Petkov wrote: > On Fri, Feb 24, 2017 at 10:15:37AM +0100, Ingo Molnar wrote: >> With thousands of call sites a one byte opcode would be preferred, that's why INT3 >> is so nice. > > ICEBP is also a single-byte: F1. And should be pretty unused :) > That would make debugging preproduction hardware on Linux a living nightmare. -hpa