Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754286AbbGXQ0e (ORCPT ); Fri, 24 Jul 2015 12:26:34 -0400 Received: from wtarreau.pck.nerim.net ([62.212.114.60]:9576 "EHLO 1wt.eu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753373AbbGXQ0d (ORCPT ); Fri, 24 Jul 2015 12:26:33 -0400 Date: Fri, 24 Jul 2015 18:25:50 +0200 From: Willy Tarreau To: Andy Lutomirski Cc: Peter Zijlstra , Linus Torvalds , Steven Rostedt , X86 ML , "linux-kernel@vger.kernel.org" , Borislav Petkov , Thomas Gleixner , Brian Gerst Subject: Re: Dealing with the NMI mess Message-ID: <20150724162550.GG3612@1wt.eu> References: <20150723173105.6795c0dc@gandalf.local.home> <20150724081326.GO25159@twins.programming.kicks-ass.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.4.2.3i Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 906 Lines: 19 On Fri, Jul 24, 2015 at 08:48:57AM -0700, Andy Lutomirski wrote: > So by the time we detect that we've hit a watchpoint, the instruction > that tripped it is done and we don't need RF. Furthermore, after > reading 17.3.1.1: I *think* that regs->flags withh have RF *clear* if > we hit a watchpoint. Apparently after reading 17.3.1.1, it seems like RF can still be set if a data breakpoint triggers in a repeated string instruction before the last iteration. However I don't think we care because as long as we return to the string instruction, since the data location was already visited it won't trigger again so the loss of the flag should be safe. Willy -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/