From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Wed, 24 Jan 2001 13:46:39 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Wed, 24 Jan 2001 13:46:30 -0500 Received: from cmn2.cmn.net ([206.168.145.10]:5450 "EHLO cmn2.cmn.net") by vger.kernel.org with ESMTP id ; Wed, 24 Jan 2001 13:46:13 -0500 Message-ID: <3A6F22D7.3000709@valinux.com> Date: Wed, 24 Jan 2001 11:45:43 -0700 From: Jeff Hartmann User-Agent: Mozilla/5.0 (X11; U; Linux 2.2.12-20smp i686; en-US; m18) Gecko/20001107 Netscape6/6.0 X-Accept-Language: en MIME-Version: 1.0 To: Timur Tabi CC: Linux Kernel Mailing list , Linux MM mailing list Subject: Re: Page Attribute Table (PAT) support? In-Reply-To: <20010124174824Z129401-18594+948@vger.kernel.org> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Timur Tabi wrote: > The Page Attribute Table (PAT) is an extension to the x86 page table format > that lets you enable Write Combining on a per-page basis. Details can be found > in chapter 9.13 of the Intel Architecture Software Developer's Manual, Volume 3 > (System Programming). > > I noticed that 2.4 doesn't support the Page Attribute Table, despite the fact > that it has a X86_FEATURE_PAT macro in processor.h. Are there any plans to add > this support? Ideally, I'd like it to be as a parameter for ioremap. I'm actually writing support for the PAT as we speak. I already have working code for PAT setup. Just having a parameter for ioremap is not enough, unfortunately. According to the Intel Architecture Software Developer's Manual we have to remove all mappings of the page that are cached. Only then can they be mapped with per page write combining. I should have working code by the 2.5.x timeframe. I can also discuss the planned interface if anyone is interested. -Jeff - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org Please read the FAQ at http://www.tux.org/lkml/