linux-kernel - Re: [PATCH 4/4] x86/efi: Allocate a trampoline if needed in efi_free_boot

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Message-ID: <5389d894-64c0-5f5f-6ed6-e08077f1dc8e@zytor.com>
Date:	Sun, 31 Jul 2016 22:07:07 -0700
From:	"H. Peter Anvin" <hpa@...or.com>
To:	Andy Lutomirski <luto@...nel.org>, x86@...nel.org
Cc:	Mario Limonciello <mario_limonciello@...l.com>,
	Matthew Garrett <mjg59@...f.ucam.org>,
	Borislav Petkov <bp@...en8.de>,
	Matt Fleming <mfleming@...e.de>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 4/4] x86/efi: Allocate a trampoline if needed in
 efi_free_boot_services()

On 07/26/16 15:55, Andy Lutomirski wrote:
> +		/*
> +		 * Nasty quirk: if all sub-1MB memory is used for boot
> +		 * services, we can get here without having allocated the
> +		 * real mode trampoline.  It's too late to hand boot services
> +		 * memory back to the memblock allocator, so instead
> +		 * try to reclaim a single page if needed.
> +		 *

This comment makes no sense.  Nowhere is there a dependency on a single
page, and this refers to allocation, not reclaim...

	-hpa