From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758093Ab0FKRns (ORCPT ); Fri, 11 Jun 2010 13:43:48 -0400 Received: from terminus.zytor.com ([198.137.202.10]:58617 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755744Ab0FKRnr (ORCPT ); Fri, 11 Jun 2010 13:43:47 -0400 Message-ID: <4C1275BF.3070605@zytor.com> Date: Fri, 11 Jun 2010 10:43:27 -0700 From: "H. Peter Anvin" User-Agent: Mozilla/5.0 (X11; U; Linux x86_64; en-US; rv:1.9.1.9) Gecko/20100430 Fedora/3.0.4-3.fc13 Thunderbird/3.0.4 MIME-Version: 1.0 To: Kenji Kaneshige CC: Thomas Gleixner , Ingo Molnar , linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org, jbarnes@virtuousgeek.org Subject: Re: [PATCH 2/4] x86: ioremap: fix physical address check References: <4C11FF10.4060203@jp.fujitsu.com> <4C11FFC0.1030006@jp.fujitsu.com> In-Reply-To: <4C11FFC0.1030006@jp.fujitsu.com> 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 06/11/2010 02:20 AM, Kenji Kaneshige wrote: > If the physical address is too high to be handled by ioremap() in > x86_32 PAE (e.g. more than 36-bit physical address), ioremap() must > return error (NULL). However, current x86 ioremap try to map this too > high physical address, and it causes unexpected behavior. What unexpected behavior? It is perfectly legitimately to map such a high address in PAE mode. We have a 36-bit kernel-imposed limit on *RAM* in 32-bit mode (because we can't manage more than that), but there is no reason it should apply to I/O. -hpa