Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755036Ab1DROwr (ORCPT ); Mon, 18 Apr 2011 10:52:47 -0400 Received: from db3ehsobe006.messaging.microsoft.com ([213.199.154.144]:21872 "EHLO DB3EHSOBE006.bigfish.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753449Ab1DROwm (ORCPT ); Mon, 18 Apr 2011 10:52:42 -0400 X-SpamScore: -28 X-BigFish: VPS-28(zzbb2dK9371O1432N98dKzz1202hzz15d4Rz32i637h668h839h62h) X-Spam-TCS-SCL: 1:0 X-Forefront-Antispam-Report: KIP:(null);UIP:(null);IPVD:NLI;H:ausb3twp02.amd.com;RD:none;EFVD:NLI X-WSS-ID: 0LJURZM-02-ASN-02 X-M-MSG: Date: Mon, 18 Apr 2011 16:52:30 +0200 From: "Roedel, Joerg" To: "H. Peter Anvin" CC: Ingo Molnar , Thomas Gleixner , "x86@kernel.org" , "linux-kernel@vger.kernel.org" , "stable@kernel.org" Subject: Re: [PATCH 4/4] x86, gart: Make sure GART does not map physmem above 1TB Message-ID: <20110418145230.GH2192@amd.com> References: <1303134346-5805-1-git-send-email-joerg.roedel@amd.com> <1303134346-5805-5-git-send-email-joerg.roedel@amd.com> <4DAC4EC0.80008@zytor.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: <4DAC4EC0.80008@zytor.com> User-Agent: Mutt/1.5.20 (2009-06-14) X-OriginatorOrg: amd.com Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 994 Lines: 28 On Mon, Apr 18, 2011 at 10:46:24AM -0400, H. Peter Anvin wrote: > On 04/18/2011 06:45 AM, Joerg Roedel wrote: > > The GART can only map physical memory below 1TB. Make sure > > the gart driver in the kernel does not try to map memory > > above 1TB. > > Where does this limit come from? >From the hardware. A GART PTE is only 32 bits in size so that it cannot be expanded. The physical address bits 32-39 are mapped 11:4 in the PTE. This can not be architecturally expanded to more than 40 physical bits. Regards, Joerg -- AMD Operating System Research Center Advanced Micro Devices GmbH Einsteinring 24 85609 Dornach General Managers: Alberto Bozzo, Andrew Bowd Registration: Dornach, Landkr. Muenchen; Registerger. Muenchen, HRB Nr. 43632 -- 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/