Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753201AbXEGBYn (ORCPT ); Sun, 6 May 2007 21:24:43 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753219AbXEGBYn (ORCPT ); Sun, 6 May 2007 21:24:43 -0400 Received: from smtp.ocgnet.org ([64.20.243.3]:45588 "EHLO smtp.ocgnet.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753201AbXEGBYm (ORCPT ); Sun, 6 May 2007 21:24:42 -0400 Date: Mon, 7 May 2007 10:24:18 +0900 From: Paul Mundt To: Greg Ungerer Cc: Robin Getz , linux-kernel@vger.kernel.org Subject: Re: [PATCH]: linux-2.6.21-uc0 (MMU-less updates) Message-ID: <20070507012418.GB25739@linux-sh.org> Mail-Followup-To: Paul Mundt , Greg Ungerer , Robin Getz , linux-kernel@vger.kernel.org References: <46382055.8030203@snapgear.com> <200705030655.36957.rgetz@blackfin.uclinux.org> <4639C164.5070908@snapgear.com> <200705030735.36879.rgetz@blackfin.uclinux.org> <4639E40D.6030809@snapgear.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4639E40D.6030809@snapgear.com> User-Agent: Mutt/1.5.13 (2006-08-11) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1905 Lines: 41 On Thu, May 03, 2007 at 11:30:53PM +1000, Greg Ungerer wrote: > Robin Getz wrote: > >>Its not an architecture problem. It can effect any board that > >>has RAM mapped at a large numerical addresses (larger than TASK_SIZE). > >>So it can effect any non-MMU platform. > > > >Depending on how TASK_SIZE is defined - it looks like everyone else forces > >it to end of memory, except 68k[nommu]. > > > >asm-arm/memory.h:#define TASK_SIZE (CONFIG_DRAM_SIZE) > >asm-blackfin/processor.h:#define TASK_SIZE (memory_end) > >asm-frv/mem-layout.h:#define TASK_SIZE __UL(0xFFFFFFFFUL) > > > >asm-m68k/processor.h:#define TASK_SIZE (0xF0000000UL) > >asm-m68k/processor.h:#define TASK_SIZE (0x0E000000) > >asm-m68k/processor.h:#define TASK_SIZE (0x0E000000UL) > >asm-m68knommu/processor.h:#define TASK_SIZE (0xF0000000UL) > > Probably too: > > asm-sh/processor.h:#define TASK_SIZE 0x7c000000UL > > which has some parts with MMU. > > There have been others out of tree that have it like this to. > It would be at 0x80000000UL on SH if it weren't for address space area limitations. The 0x7c000000 - 0x7fffffff space is used for shadowing P4 registers in the virtual address space (area 7) with the MMU and it's a reserved area without the MMU, so TASK_SIZE is trimmed right before this. However, I'm not sure that the patch Greg has in this set is sufficient for the problem described. do_mmap_pgoff() won't allow a > TASK_SIZE mapping anyways. In the SH case we certainly have address spaces that can be given user permissions well above TASK_SIZE, area 7 space is used as a bit of a hack for some of this in the MMU case.. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/