linux-kernel - Re: [RFC v2 0/2] Early use of boot service memory

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Message-ID: <20131121230744.GA31592@srcf.ucam.org>
Date:	Thu, 21 Nov 2013 23:07:44 +0000
From:	Matthew Garrett <mjg59@...f.ucam.org>
To:	Jerry Hoemann <jerry.hoemann@...com>
Cc:	rob@...dley.net, tglx@...utronix.de, mingo@...hat.com,
	hpa@...or.com, x86@...nel.org, matt.fleming@...el.com,
	yinghai@...nel.org, akpm@...ux-foundation.org, bp@...e.de,
	linux-doc@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-efi@...r.kernel.org, penberg@...nel.org,
	mingo.kernel.org@...il.com, vgoyal@...hat.com
Subject: Re: [RFC v2 0/2] Early use of boot service memory

On Thu, Nov 21, 2013 at 02:01:24PM -0700, Jerry Hoemann wrote:
> 
> Some platform have firmware that violates the UEFI spec and access boot
> service code or data segments after the system has called ExitBootServices().
> The call to efi_reserve_boot_services in setup_arch is a workaround to
> avoid using boot service memory until after the kernel has done
> SetVirtualAddressMap.  However, this reservation fragments memory
> which can cause large allocations early in boot (e.g. crash kernel)
> to fail.

This is a problem we have to solve, but I don't think this is the right 
way to solve it. Why do we not just reattempt to perform the allocation 
immediately after we've freed the boot services regions?

-- 
Matthew Garrett | mjg59@...f.ucam.org
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