From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755239AbXLGMES (ORCPT ); Fri, 7 Dec 2007 07:04:18 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751127AbXLGMEG (ORCPT ); Fri, 7 Dec 2007 07:04:06 -0500 Received: from moutng.kundenserver.de ([212.227.126.186]:62519 "EHLO moutng.kundenserver.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751399AbXLGMEF convert rfc822-to-8bit (ORCPT ); Fri, 7 Dec 2007 07:04:05 -0500 From: Arnd Bergmann To: linuxppc-dev@ozlabs.org Subject: Re: [RFC][POWERPC] Provide a way to protect 4k subpages when using 64k pages Date: Fri, 7 Dec 2007 13:03:41 +0100 User-Agent: KMail/1.9.6 (enterprise 0.20070907.709405) Cc: Paul Mackerras , linux-kernel@vger.kernel.org References: <18264.58263.818005.757831@cargo.ozlabs.ibm.com> In-Reply-To: <18264.58263.818005.757831@cargo.ozlabs.ibm.com> X-Face: I@=L^?./?$U,EK.)V[4*>`zSqm0>65YtkOe>TFD'!aw?7OVv#~5xd\s,[~w]-J!)|%=]>=?utf-8?q?+=0A=09=7EohchhkRGW=3F=7C6=5FqTmkd=5Ft=3FLZC=23Q-=60=2E=60Y=2Ea=5E?= =?utf-8?q?3zb?=) =?utf-8?q?+U-JVN=5DWT=25cw=23=5BYo0=267C=26bL12wWGlZi=0A=09=7EJ=3B=5Cwg?= =?utf-8?q?=3B3zRnz?=,J"CT_)=\H'1/{?SR7GDu?WIopm.HaBG=QYj"NZD_[zrM\Gip^U MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 8BIT Content-Disposition: inline Message-Id: <200712071303.42413.arnd@arndb.de> X-Provags-ID: V01U2FsdGVkX19byRNl0qQQtlcmWO5xKO9o/IpwbIM6PZ14/7O MhGSzZi8/ywDCbjaCdXoG1wm3FgCHgeYdW11tP006kv1eXDOTs uInE2bUAlWzOrvDTx0uxA== Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Friday 07 December 2007, Paul Mackerras wrote: > I have re-purposed the ioperm system call for this.  The old ioperm > system call never did anything (except return an ENOSYS error) and in > fact never could have actually been useful for anything on the PowerPC > architecture, so nothing ever used it. Couldn't there be a program that relies on ioperm to return -ENOSYS on powerpc in order to fall back on some other method of I/O access? The risk of actually breaking something is certainly low, but I think you can never be sure here, so why not use a new syscall number? Arnd <><