From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S933797AbbBCMZ7 (ORCPT <rfc822;w@1wt.eu>);
	Tue, 3 Feb 2015 07:25:59 -0500
Received: from mail-la0-f43.google.com ([209.85.215.43]:44867 "EHLO
	mail-la0-f43.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S932933AbbBCMZ4 (ORCPT
	<rfc822;linux-kernel@vger.kernel.org>);
	Tue, 3 Feb 2015 07:25:56 -0500
From: Alex Kuleshov <kuleshovmail@gmail.com>
To: linux-kernel@vger.kernel.org
Subject: [x86_64] Question about early page tables initialization
Date: Tue, 03 Feb 2015 18:25:32 +0600
Message-ID: <87egq7dvwj.fsf@gmail.com>
MIME-Version: 1.0
Content-Type: text/plain
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

Hello All,

I have a question about page tables initialization in the
arch/x86/boot/compressed/head_64.S

After we clear memory for page tables, there is code which
build PML4:

	leal	pgtable + 0(%ebx), %edi
	leal	0x1007(%edi), %eax      
	movl	%eax, 0(%edi)
        
Why there is offset 0x1007 instead just 0x7? 0x1007 is
4k + 7bit (PML4E) flags as i understand correctly. But
why we skip first 4k here?

Thank you.