Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933785AbbENRIF (ORCPT ); Thu, 14 May 2015 13:08:05 -0400 Received: from mail-ig0-f179.google.com ([209.85.213.179]:33649 "EHLO mail-ig0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932923AbbENRIC (ORCPT ); Thu, 14 May 2015 13:08:02 -0400 MIME-Version: 1.0 In-Reply-To: References: <1431622519-19718-1-git-send-email-dvlasenk@redhat.com> Date: Thu, 14 May 2015 10:08:01 -0700 X-Google-Sender-Auth: 3FV5AnyvWteZkaql_N8AQlRkhPI Message-ID: Subject: Re: [PATCH] x86/asm/entry/64: Use shorter MOVs from segmers registers From: Linus Torvalds To: Denys Vlasenko Cc: Ingo Molnar , Steven Rostedt , Borislav Petkov , "H. Peter Anvin" , Andy Lutomirski , Oleg Nesterov , Frederic Weisbecker , Alexei Starovoitov , Will Drewry , Kees Cook , "the arch/x86 maintainers" , Linux Kernel Mailing List Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 916 Lines: 20 On Thu, May 14, 2015 at 10:05 AM, Linus Torvalds wrote: > > I don't object to the patch, but did we actually confirm that it > always overwrites all of %ecx? Just to clarify: I don't object to the patch because the code doesn't actually end up *depending* on the high bits anyway, and does word-sized compares etc. And the instruction size and speed things I don't doubt. So it's just the commit message I wanted to check wrt that whole "always overwrites all of %ecx". Because older CPU's didn't necessarily (things like partial register writes are much less of an issue when you're in-order and stupid ;) Linus -- 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/