Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261630AbTIRQFT (ORCPT ); Thu, 18 Sep 2003 12:05:19 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S261585AbTIRQFT (ORCPT ); Thu, 18 Sep 2003 12:05:19 -0400 Received: from mail.jlokier.co.uk ([81.29.64.88]:51093 "EHLO mail.jlokier.co.uk") by vger.kernel.org with ESMTP id S261903AbTIRQFP (ORCPT ); Thu, 18 Sep 2003 12:05:15 -0400 Date: Thu, 18 Sep 2003 17:04:56 +0100 From: Jamie Lokier To: Andi Kleen Cc: Linus Torvalds , Nick Piggin , Andrew Morton , linux-kernel@vger.kernel.org, richard.brunner@amd.com Subject: Re: [PATCH] Athlon/Opteron Prefetch Fix for 2.6.0test5 + numbers Message-ID: <20030918160456.GC7548@mail.jlokier.co.uk> References: <20030917202100.GC4723@wotan.suse.de> <20030917211200.GA5997@wotan.suse.de> <20030918153831.GA7548@mail.jlokier.co.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20030918153831.GA7548@mail.jlokier.co.uk> User-Agent: Mutt/1.4.1i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 832 Lines: 21 Jamie Lokier wrote: > > + /* Don't check for LDT code segments because they could have > > + non zero bases. Better would be to add in the base in this case. */ > > + if (regs->xcs & (1<<2)) > > + return 0; > > It is possible to have a non-standard code segment in the GDT, too. > Thus a better to check is "unlikely((regs->xcs & 0xffff) != __USER_CS)". Ignore me here, I'm being dense - forgetting about __KERNEL_CS :) My point is simply that non-zero base GDT segments are possible in userspace, and whatever code you add later to add the base should be aware of that. -- Jamie - 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/