From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755507Ab2LRWYk (ORCPT ); Tue, 18 Dec 2012 17:24:40 -0500 Received: from terminus.zytor.com ([198.137.202.10]:34419 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754840Ab2LRWYi (ORCPT ); Tue, 18 Dec 2012 17:24:38 -0500 Message-ID: <50D0ED00.60804@zytor.com> Date: Tue, 18 Dec 2012 14:24:00 -0800 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/17.0 Thunderbird/17.0 MIME-Version: 1.0 To: Andy Lutomirski CC: Stefani Seibold , linux-kernel@vger.kernel.org, x86@kernel.org, tglx@linutronix.de, mingo@redhat.com, ak@linux.intel.com, aarcange@redhat.com, john.stultz@linaro.org, xemul@parallels.com, gorcunov@openvz.org, andriy.shevchenko@linux.intel.com Subject: Re: [PATCH 6/6] Add 32 bit VDSO support for 32 and 64 bit kernels References: <1355823656-13902-1-git-send-email-stefani@seibold.net> <1355823656-13902-7-git-send-email-stefani@seibold.net> <50D09733.3080502@zytor.com> <1355849558.26967.24.camel@wall-e> <50D0B986.7020009@zytor.com> <1355862759.28056.14.camel@wall-e> In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 12/18/2012 12:37 PM, Andy Lutomirski wrote: >> >> There is no introduce of new fix address. There are still there for >> x86_64. If this will currently not a major problem on this architecture >> than it will not for x86_32 too. > > Not necessarily true. On x86-64 (non-compat) the fixmap address is in > kernel space (high bit set), so it can't conflict with anything in > user space. On true 32-bit mode, the same applies. In compat mode, > the fixed address is in *user* space and might conflict with existing > uses. > The other bit is that the fixmap isn't actually fixed on 32 bits, which creates its own set of problems. As such, I really would prefer a properly PIC solution. -hpa -- H. Peter Anvin, Intel Open Source Technology Center I work for Intel. I don't speak on their behalf.