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 S1757621Ab3ANT5h (ORCPT <rfc822;w@1wt.eu>);
	Mon, 14 Jan 2013 14:57:37 -0500
Received: from terminus.zytor.com ([198.137.202.10]:57308 "EHLO mail.zytor.com"
	rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
	id S1756149Ab3ANT5g (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
	Mon, 14 Jan 2013 14:57:36 -0500
Message-ID: <50F46304.3010108@zytor.com>
Date: Mon, 14 Jan 2013 11:56:52 -0800
From: "H. Peter Anvin" <hpa@zytor.com>
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/17.0 Thunderbird/17.0
MIME-Version: 1.0
To: Yinghai Lu <yinghai@kernel.org>
CC: Borislav Petkov <bp@alien8.de>, Thomas Gleixner <tglx@linutronix.de>,
        Ingo Molnar <mingo@elte.hu>,
        "Eric W. Biederman" <ebiederm@xmission.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Jan Kiszka <jan.kiszka@web.de>,
        Jason Wessel <jason.wessel@windriver.com>,
        linux-kernel@vger.kernel.org, Rob Landley <rob@landley.net>,
        Matt Fleming <matt.fleming@intel.com>,
        Gokul Caushik <caushik1@gmail.com>,
        Josh Triplett <josh@joshtriplett.org>,
        Joe Millenbach <jmillenbach@gmail.com>
Subject: Re: [PATCH v7u1 22/31] x86, boot: add fields to support load bzImage
 and ramdisk above 4G
References: <1357260531-11115-1-git-send-email-yinghai@kernel.org> <1357260531-11115-23-git-send-email-yinghai@kernel.org> <20130113214132.GB17200@liondog.tnic> <CAE9FiQVQRAOtw7kiPJO3xszJx9uPFjgK82PjbvTyqzJgujdicw@mail.gmail.com> <50F4452D.2060000@zytor.com> <CAE9FiQXkgoLKp3ZnOcM9gLDJNGNxUE8WSRXiQy1G_v5Os5_v2A@mail.gmail.com> <50F455A3.4070706@zytor.com> <CAE9FiQUtbpo0njyPjPED=esKKnSdFs9ry4pFjG1y0LvHxkqV4w@mail.gmail.com>
In-Reply-To: <CAE9FiQUtbpo0njyPjPED=esKKnSdFs9ry4pFjG1y0LvHxkqV4w@mail.gmail.com>
X-Enigmail-Version: 1.4.6
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 7bit
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On 01/14/2013 11:50 AM, Yinghai Lu wrote:
> On Mon, Jan 14, 2013 at 10:59 AM, H. Peter Anvin <hpa@zytor.com> wrote:
>> No, there were other fields that were also left uninitialized, per your
>> analysis from last year.  I don't remember the details, but I seem to
>> recall they included the EFI and graphics-related fields.
>>
>> So yes, just zero them all out.
> 
> ?
> 

Yep.

> +static void sanitize_real_mode(struct boot_params *real_mode)
> +{
> +       if (real_mode->sentinel) {
> +               /*fields in boot_params are not valid, clear them */
> +               memset(&real_mode->olpc_ofw_header, 0,
> +                      (char *)&real_mode->alt_mem_k -
> +                       (char *)&real_mode->olpc_ofw_header);
> +               memset(&real_mode->_pad7[0], 0,
> +                      (char *)&real_mode->edd_mbr_sig_buffer[0] -
> +                       (char *)&real_mode->_pad7[0]);
> +               memset(&real_mode->_pad8[0], 0,
> +                      (char *)&real_mode->eddbuf[0] -
> +                       (char *)&real_mode->_pad8[0]);
> +               memset(&real_mode->_pad9[0], 0, sizeof(real_mode->_pad9));
> +       }
> +}
> +
>