From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752788Ab3BJIgU (ORCPT ); Sun, 10 Feb 2013 03:36:20 -0500 Received: from mail.skyhub.de ([78.46.96.112]:50662 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752373Ab3BJIgT (ORCPT ); Sun, 10 Feb 2013 03:36:19 -0500 Date: Sun, 10 Feb 2013 09:36:16 +0100 From: Borislav Petkov To: "H. Peter Anvin" Cc: X86 ML , LKML , Borislav Petkov Subject: Re: [PATCH 2/5 -v2.1] x86: Detect CPUID support early at boot Message-ID: <20130210083616.GA4878@pd.tnic> Mail-Followup-To: Borislav Petkov , "H. Peter Anvin" , X86 ML , LKML , Borislav Petkov References: <20130209231351.GB5556@pd.tnic> <1360451762-10175-1-git-send-email-bp@alien8.de> <5117236D.5000607@zytor.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <5117236D.5000607@zytor.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Feb 09, 2013 at 08:34:53PM -0800, H. Peter Anvin wrote: > I wouldn't really call it a "side effect". Perhaps the right thing > here is to say something like "we want to start out with %eflags > unambiguously clear". > > (Note also we have had to CLD earlier because we have already copied > the command line.) Ok, let's make it even more verbose so that people know in the future: "... we want to start out with EFLAGS unambiguously clear. That means DF in particular (even though we have cleared it earlier after copying the command line) because GCC expects it." How does that sound? Also, I was wondering about the whole reasoning behind that: do you know why DF=0 is a GCC requirement? I mean, nothing hurts GCC from issuing a CLD each time? Thanks. -- Regards/Gruss, Boris. Sent from a fat crate under my desk. Formatting is fine. --