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 S1755465AbdEKLSh (ORCPT <rfc822;w@1wt.eu>);
        Thu, 11 May 2017 07:18:37 -0400
Received: from mail.skyhub.de ([5.9.137.197]:60800 "EHLO mail.skyhub.de"
        rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
        id S1753303AbdEKLSg (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
        Thu, 11 May 2017 07:18:36 -0400
Date: Thu, 11 May 2017 13:18:28 +0200
From: Borislav Petkov <bp@alien8.de>
To: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
Cc: linux-efi@vger.kernel.org, linux-kernel@vger.kernel.org,
        Ricardo Neri <ricardo.neri@intel.com>,
        Matt Fleming <matt@codeblueprint.co.uk>,
        Ard Biesheuvel <ard.biesheuvel@linaro.org>,
        Ravi Shankar <ravi.v.shankar@intel.com>
Subject: Re: [PATCH] x86/efi: Add EFI_PGT_DUMP support for x86_32, kexec and
 efi=old_map
Message-ID: <20170511111828.pu2i3pn6lyiukgaf@pd.tnic>
References: <1494456545-26300-1-git-send-email-sai.praneeth.prakhya@intel.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
In-Reply-To: <1494456545-26300-1-git-send-email-sai.praneeth.prakhya@intel.com>
User-Agent: NeoMutt/20170113 (1.7.2)
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Wed, May 10, 2017 at 03:49:05PM -0700, Sai Praneeth Prakhya wrote:
> From: Sai Praneeth <sai.praneeth.prakhya@intel.com>
> 
> EFI_PGT_DUMP, as the name suggests dumps efi page tables to dmesg during
> kernel boot. This feature is very useful while debugging page
> faults/null pointer dereferences to efi related addresses. Presently,
> this feature is limited only to x86_64, so let's extend it to other efi
> configurations like kexec kernel, efi=old_map and to x86_32 as well.
> This doesn't effect normal boot path because this config option should
> be used only for debug purposes.
> 
> Signed-off-by: Sai Praneeth Prakhya <sai.praneeth.prakhya@intel.com>
> Cc: Borislav Petkov <bp@alien8.de>
> Cc: Ricardo Neri <ricardo.neri@intel.com>
> Cc: Matt Fleming <matt@codeblueprint.co.uk>
> Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
> Cc: Ravi Shankar <ravi.v.shankar@intel.com>
> ---
>  arch/x86/platform/efi/efi.c    | 2 ++
>  arch/x86/platform/efi/efi_32.c | 9 ++++++++-
>  arch/x86/platform/efi/efi_64.c | 5 ++++-
>  3 files changed, 14 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/x86/platform/efi/efi.c b/arch/x86/platform/efi/efi.c
> index 217dc166c649..a6d6cd8fe78a 100644
> --- a/arch/x86/platform/efi/efi.c
> +++ b/arch/x86/platform/efi/efi.c
> @@ -890,6 +890,8 @@ static void __init kexec_enter_virtual_mode(void)
>  	if (efi_enabled(EFI_OLD_MEMMAP) && (__supported_pte_mask & _PAGE_NX))
>  		runtime_code_page_mkexec();
>  
> +	efi_dump_pagetable();

You can call that only once at the end of efi_enter_virtual_mode()
instead of adding it here and leaving it in __efi_enter_virtual_mode().

-- 
Regards/Gruss,
    Boris.

Good mailing practices for 400: avoid top-posting and trim the reply.