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

From: Josh Triplett <josh@joshtriplett.org>
To: "H. Peter Anvin" <hpa@zytor.com>
Cc: Matt Fleming <matt.fleming@intel.com>,
	linux-kernel@vger.kernel.org,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>,
	x86@kernel.org, Len Brown <lenb@kernel.org>,
	Olof Johansson <olof@lixom.net>, Matthew Garrett <mjg@redhat.com>,
	David Howells <dhowells@redhat.com>,
	Rusty Russell <rusty@rustcorp.com.au>,
	Jim Cromie <jim.cromie@gmail.com>,
	Peter Zijlstra <a.p.zijlstra@chello.nl>,
	Pawel Moll <pawel.moll@arm.com>,
	linux-acpi@vger.kernel.org, linux-efi <linux-efi@vger.kernel.org>
Subject: Re: [PATCH 0/3] Fix ACPI BGRT support for images located in EFI boot services memory
Date: Tue, 4 Sep 2012 13:29:26 -0700	[thread overview]
Message-ID: <20120904202925.GA5805@jtriplet-mobl1> (raw)
In-Reply-To: <50466363.9010900@zytor.com>

On Tue, Sep 04, 2012 at 01:24:03PM -0700, H. Peter Anvin wrote:
> 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.

OK, will do.

> >>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.

Fair enough.  I'll send v2 shortly.

- Josh Triplett