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 15:48:25 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Wed, 24 Jan 2001 15:48:15 -0500 Received: from jump-isi.interactivesi.com ([207.8.4.2]:60399 "HELO dinero.interactivesi.com") by vger.kernel.org with SMTP id ; Wed, 24 Jan 2001 15:48:06 -0500 Date: Wed, 24 Jan 2001 14:48:05 -0600 From: Timur Tabi To: Linux Kernel Mailing list Cc: Linux MM mailing list In-Reply-To: <3A6F3E05.4090409@valinux.com> In-Reply-To: <20010124174824Z129401-18594+948@vger.kernel.org> <20010124203012Z129444-18594+1042@vger.kernel.org> Subject: Re: Page Attribute Table (PAT) support? X-Mailer: The Polarbar Mailer; version=1.19a; build=73 Message-Id: <20010124204811Z129375-18594+1059@vger.kernel.org> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org ** Reply to message from Jeff Hartmann on Wed, 24 Jan 2001 13:41:41 -0700 > When you mark a page UCWC, you better > have removed all cached mappings or your asking for REAL trouble. What exactly do you mean by "removed all cached mappings"? Does that mean that if one virtual address is a UCWC mapping of a physical page, then ALL virtual addresses mapped to that page must also be UCWC? In my driver, I use ioremap_nocache() on physical memory (real RAM) to create an uncached "alias" (a virtual address) to a physical page of RAM. When I access the memory via this virtual address, the memory access is not cached. What I reall need is to be able to also have that virtual address as Write Combined. Since all physical RAM is mapped as cached via the kernel (on a 1-to-1 basis), and since there can be several other virtual addresses that point to that memory (e.g. user virtual address), I can't see how these virtual addresses can be removed. -- Timur Tabi - ttabi@interactivesi.com Interactive Silicon - http://www.interactivesi.com When replying to a mailing-list message, please direct the reply to the mailing list only. Don't send another copy to me. - 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/