From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S266352AbUGOWGZ (ORCPT ); Thu, 15 Jul 2004 18:06:25 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266357AbUGOWGZ (ORCPT ); Thu, 15 Jul 2004 18:06:25 -0400 Received: from cantor.suse.de ([195.135.220.2]:18142 "EHLO Cantor.suse.de") by vger.kernel.org with ESMTP id S266352AbUGOWGU (ORCPT ); Thu, 15 Jul 2004 18:06:20 -0400 Date: Fri, 16 Jul 2004 00:06:18 +0200 From: Andi Kleen To: Roland McGrath Cc: akpm@osdl.org, torvalds@osdl.org, linux-kernel@vger.kernel.org, jparadis@redhat.com, cagney@redhat.com, discuss@x86-64.org Subject: Re: [PATCH] x86-64 singlestep through sigreturn system call Message-Id: <20040716000618.0441d268.ak@suse.de> In-Reply-To: <200407152113.i6FLDFfB013246@magilla.sf.frob.com> References: <20040715074618.4c33bd31.ak@suse.de> <200407152113.i6FLDFfB013246@magilla.sf.frob.com> X-Mailer: Sylpheed version 0.9.11 (GTK+ 1.2.10; i686-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thu, 15 Jul 2004 14:13:15 -0700 Roland McGrath wrote: > > Anyways, I don't have any plans to change the 64bit behaviour. gdb will > > have to live with a few minor inconsistencies as price for faster system > > calls. > > My patch doesn't slow anything down beyond one comparison and branch not > taken in the rt_sigreturn system call. Does that negligible meaning of > "faster" really warrant the inconsistent user behavior? I meant as a general side effect of using SYSRET and not always IRET. In the later case it would be consistently like i386. Anyways, even if I applied your patch there would be still inconsistency because there are several other system calls that use IRET. So I don't see much advantage in adding a special case just for sigreturn. -Andi