linux-kernel - Re: [PATCH 0/3] Fix ACPI BGRT support for images located in EFI boot services memory

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Message-ID: <50466363.9010900@zytor.com>
Date:	Tue, 04 Sep 2012 13:24:03 -0700
From:	"H. Peter Anvin" <hpa@...or.com>
To:	Josh Triplett <josh@...htriplett.org>
CC:	Matt Fleming <matt.fleming@...el.com>,
	linux-kernel@...r.kernel.org, Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>, x86@...nel.org,
	Len Brown <lenb@...nel.org>, Olof Johansson <olof@...om.net>,
	Matthew Garrett <mjg@...hat.com>,
	David Howells <dhowells@...hat.com>,
	Rusty Russell <rusty@...tcorp.com.au>,
	Jim Cromie <jim.cromie@...il.com>,
	Peter Zijlstra <a.p.zijlstra@...llo.nl>,
	Pawel Moll <pawel.moll@....com>, linux-acpi@...r.kernel.org,
	linux-efi <linux-efi@...r.kernel.org>
Subject: Re: [PATCH 0/3] Fix ACPI BGRT support for images located in EFI boot
 services memory

On 09/04/2012 12:45 PM, Josh Triplett wrote:
>>
>> There are some platforms which have bugs in this area, so there are
>> other reasons to defer freeing up boot memory until as late in the
>> boot process as we can possibly get away with.
>>
>> free_initmem() is presuambly the place that makes most sense.
>
> You're suggesting a call from free_initmem() to
> efi_free_boot_services()?  Or, from init_post() right before the call to
> free_initmem()?
>

free_initmem() is arch-specific, so probably the latter.

>> This
>> is EFI-specific but not x86-specific, let's not commingle those
>> concepts, please...
>
> init/main.c already calls the x86-specific efi_enter_virtual_mode
> (defined in arch/x86/platform/efi/efi.c), and I split the call to the
> x86-specific efi_free_boot_services out of that.  Neither of those
> functions exists on non-x86 platforms, and thus I mirrored the #ifdef
> currently wrapped around efi_enter_virtual_mode for the new call to
> efi_free_boot_services.  While it might make sense for that code to
> exist on non-x86 EFI platforms, it currently doesn't.  At best, I could
> add static inline stubs to linux/efi.h for those functions to avoid the
> ifdefs, but as far as I can tell the same issue applies to quite a few
> more functions in efi.h.
>
> Would you like me to add the static inline stubs for the couple of
> functions called from init/main.c, or leave the #ifdefs?
>

I think that would really help clean things up.

	-hpa



-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.

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