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 S1753660AbbIRObn (ORCPT <rfc822;w@1wt.eu>);
	Fri, 18 Sep 2015 10:31:43 -0400
Received: from foss.arm.com ([217.140.101.70]:46652 "EHLO foss.arm.com"
	rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
	id S1752342AbbIRObm (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
	Fri, 18 Sep 2015 10:31:42 -0400
Date: Fri, 18 Sep 2015 15:31:24 +0100
From: Mark Rutland <mark.rutland@arm.com>
To: Mark Salter <msalter@redhat.com>
Cc: Catalin Marinas <Catalin.Marinas@arm.com>,
        Will Deacon <Will.Deacon@arm.com>,
        Matt Fleming <matt.fleming@intel.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "linux-arm-kernel@lists.infradead.org" 
	<linux-arm-kernel@lists.infradead.org>,
        Ard Biesheuvel <ard.biesheuvel@linaro.org>
Subject: Re: [PATCH] arm64: dmi: initialize DMI earlier in boot
Message-ID: <20150918143124.GA31683@leverpostej>
References: <1442585666-14093-1-git-send-email-msalter@redhat.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <1442585666-14093-1-git-send-email-msalter@redhat.com>
User-Agent: Mutt/1.5.21 (2010-09-15)
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Fri, Sep 18, 2015 at 03:14:26PM +0100, Mark Salter wrote:
> Currently, DMI initialization takes place in a core initcall. This
> limits how early in boot the kernel can make DMI-based decisions
> about firmware/hardware quirks. This patch moves DMI initialization
> to setup_arch() so that DMI info is available before initcalls run.

Which firmware/hardware quirks in particular necessitate moving this?

> 
> ---
>  arch/arm64/include/asm/dmi.h | 19 ++++++++++++++++---
>  arch/arm64/kernel/efi.c      | 15 ---------------
>  arch/arm64/kernel/setup.c    |  5 +++++
>  3 files changed, 21 insertions(+), 18 deletions(-)
> 
> diff --git a/arch/arm64/include/asm/dmi.h b/arch/arm64/include/asm/dmi.h
> index 69d37d8..e6389fd 100644
> --- a/arch/arm64/include/asm/dmi.h
> +++ b/arch/arm64/include/asm/dmi.h
> @@ -16,16 +16,29 @@
>  
>  #include <linux/io.h>
>  #include <linux/slab.h>
> +#include <linux/memblock.h>

Nit: please keep includes ordered (given they were already).

[...]

> @@ -413,20 +412,6 @@ static int __init arm64_enable_runtime_services(void)
>  }
>  early_initcall(arm64_enable_runtime_services);
>  
> -static int __init arm64_dmi_init(void)
> -{
> -	/*
> -	 * On arm64, DMI depends on UEFI, and dmi_scan_machine() needs to
> -	 * be called early because dmi_id_init(), which is an arch_initcall
> -	 * itself, depends on dmi_scan_machine() having been called already.
> -	 */
> -	dmi_scan_machine();
> -	if (dmi_available)
> -		dmi_set_dump_stack_arch_desc();
> -	return 0;
> -}
> -core_initcall(arm64_dmi_init);
> -
>  static void efi_set_pgd(struct mm_struct *mm)
>  {
>  	if (mm == &init_mm)
> diff --git a/arch/arm64/kernel/setup.c b/arch/arm64/kernel/setup.c
> index dc9eb5f..200c2e9 100644
> --- a/arch/arm64/kernel/setup.c
> +++ b/arch/arm64/kernel/setup.c
> @@ -46,6 +46,7 @@
>  #include <linux/efi.h>
>  #include <linux/personality.h>
>  #include <linux/psci.h>
> +#include <linux/dmi.h>
>  
>  #include <asm/acpi.h>
>  #include <asm/fixmap.h>
> @@ -436,6 +437,10 @@ void __init setup_arch(char **cmdline_p)
>  	relocate_initrd();
>  	request_standard_resources();
>  
> +	dmi_scan_machine();
> +	if (dmi_available)
> +		dmi_set_dump_stack_arch_desc();

We should have a comment as to why this needs to happen so early (much
like we used to).

Mark.