From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752407AbaCLVhu (ORCPT ); Wed, 12 Mar 2014 17:37:50 -0400 Received: from mga11.intel.com ([192.55.52.93]:57632 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751721AbaCLVhs (ORCPT ); Wed, 12 Mar 2014 17:37:48 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.97,641,1389772800"; d="scan'208";a="490797078" Message-ID: <5320D3AB.5060002@linux.intel.com> Date: Wed, 12 Mar 2014 14:37:47 -0700 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.3.0 MIME-Version: 1.0 To: Linus Torvalds , Stefani Seibold CC: Andy Lutomirski , "linux-kernel@vger.kernel.org" , the arch/x86 maintainers , Dave Jones , Martin Runge , Andreas Brief , Greg Kroah-Hartman Subject: Re: [PATCH v2] x86: Remove compat vdso support References: <531F365B.4060000@linux.intel.com> <531F3D02.30706@linux.intel.com> <1394613046.995.51.camel@wall-e.seibold.net> In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 03/12/2014 12:41 PM, Linus Torvalds wrote: > > So my reaction was "don't do that". > > But people pointing out that we can't do what x86-64 does made me > think: we could avoid the whole "nasty code for a legacy case" by > making it the *non*-legacy case. We could get rid of the fixmap > HPET/VVAR entirely - on x86-64 (which can use those addresses) a > PC-relative addressing is probably actually better anyway, so mapping > them together with the vdso code shouldn't hurt. > How would that deal with the legacy vsyscall case for x86-64? Just rely on the "legacy vsyscall emulation" (which seems to have its own class of problems...)? -hpa