Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752574AbbDCRu3 (ORCPT ); Fri, 3 Apr 2015 13:50:29 -0400 Received: from mail.skyhub.de ([78.46.96.112]:58405 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751923AbbDCRu1 (ORCPT ); Fri, 3 Apr 2015 13:50:27 -0400 Date: Fri, 3 Apr 2015 19:48:24 +0200 From: Borislav Petkov To: Quentin Casasnovas Cc: X86 ML , LKML , "H. Peter Anvin" , Ingo Molnar , Thomas Gleixner , Oleg Nesterov , Andy Lutomirski Subject: Re: [PATCH] x86/xsave: Robustify and merge macros Message-ID: <20150403174824.GL3418@pd.tnic> References: <1427980282-25929-1-git-send-email-bp@alien8.de> <20150402155210.GB6703@chrystal.uk.oracle.com> <20150402161259.GE3483@pd.tnic> <20150403140630.GD14902@chrystal.uk.oracle.com> <20150403141426.GE14902@chrystal.uk.oracle.com> <20150403152324.GG3418@pd.tnic> <20150403154055.GF14902@chrystal.uk.oracle.com> <20150403170625.GJ3418@pd.tnic> <20150403173306.GG14902@chrystal.uk.oracle.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20150403173306.GG14902@chrystal.uk.oracle.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1338 Lines: 43 On Fri, Apr 03, 2015 at 07:33:06PM +0200, Quentin Casasnovas wrote: > > Basically, the idea was: > > > > .skip len(repl1) - len(orig), 0x90 > > .skip len(repl2) - len(repl1), 0x90 > > > > BUT!, for some reason I changed it to what's there now and I can't > > remember why anymore. > > I think it would not work in the case where repl1 is smaller or equal than > orig_insn (i.e. no padding in the first .skip) but orig_insn is strictly > smaller than repl2 (since we're never comparing repl2 with insn in this > new-old code). orig_insn=4 repl1=3 repl2=5 .skip 0, 0x90 .skip 2, 0x90 I think that still works, only the padding is larger than it needs to be. And it is so many bytes larger as len(abs(repl1 - orig_insn)) is. In the example above, we'll get two bytes padding while only 1 suffices. > Anything wrong with the two different approaches I've suggested in my > original mail? Right now, I want to have a minimal fix for obvious reasons. We can always improve stuff later when there's more time. -- Regards/Gruss, Boris. ECO tip #101: Trim your mails when you reply. -- -- 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/