From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757388AbXGBKXc (ORCPT ); Mon, 2 Jul 2007 06:23:32 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751298AbXGBKXX (ORCPT ); Mon, 2 Jul 2007 06:23:23 -0400 Received: from nf-out-0910.google.com ([64.233.182.185]:54682 "EHLO nf-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751368AbXGBKXW (ORCPT ); Mon, 2 Jul 2007 06:23:22 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=beta; h=received:date:to:cc:subject:message-id:references:mime-version:content-type:content-disposition:in-reply-to:user-agent:from; b=WBvbM+9QAjqqyF7gstdUvcdCtQJuZhidffzVaMTGgPitGZuVG/yO5xaLlUbCG+oCzaKFqI07H5Vl8tv4DLe4QoLMAGYft4/uA55xBhCa37n4Sg/IJ3LqbNxSvyAvyAIJCqHsQADajtKaqlsoshb4VTAZU/nFgsdeFAlD28MWKHg= Date: Mon, 2 Jul 2007 13:23:03 +0300 To: Andreas Schwab Cc: Jeremy Fitzhardinge , linux-kernel@vger.kernel.org Subject: Re: [i386] Questions regarding provisional page tables initialization Message-ID: <20070702102303.GA17533@Ahmed> References: <20070701203833.GA3498@Ahmed> <46882872.7040005@goop.org> <20070702011332.GA3503@Ahmed> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.11 From: "Ahmed S. Darwish" Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Hi Andreas, On Mon, Jul 02, 2007 at 11:18:08AM +0200, Andreas Schwab wrote: > "Ahmed S. Darwish" writes: > > > yes, but isn't the displacement here (0x007) a _bytes_ displacement ?. so > > effectively, %ecx now contains physical address of pg0 + 7bytes. Is it A > > meaningful place/address ?. > > It's not pg0 + 7bytes, it is pg0 plus 3 flag bits. Since a page address > is always page aligned, the low bits are reused for flags. > I'm sure there's a problem in _my_ understanding, but isn't the displacement - as specified by AT&T syntax - represented in bytes ?. I've wrote a small assembly function to be sure: .data integer: .string "%d\n" .text test_func: push %ebp mov %esp, %ebp push 0x008(%ebp) ## 8 bytes displacement (the first arg), right ? push $integer call printf mov %ebp, %esp pop %ebp ret The above method works fine and prints "5" to stdout by the code: .global main main: mov $5, %eax push %eax call test_func movl $1, %eax movl $0, %ebx int $0x80 now back to head.S code: leal 0x007(%edi),%ecx /* Create PDE entry */ Isn't the above line the same condition (bytes, not bits displacement) ?. Thanks for your patience !. (For other kind replies, don't understand me wrong. I did my homework and studied the pte format before asking ;). It's just the bytes/bits issue above that confuses me). -- Ahmed S. Darwish HomePage: http://darwish.07.googlepages.com Blog: http://darwish-07.blogspot.com