linux-kernel - Re: [PATCH V2 1/3] efi: arch, x86: arch, ia64: move efi_mem

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Date:	Fri, 5 Jun 2015 10:23:17 +0100
From:	Matt Fleming <matt@...eblueprint.co.uk>
To:	"Zhang, Jonathan Zhixiong" <zjzhang@...eaurora.org>
Cc:	Matt Fleming <matt.fleming@...el.com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Ingo Molnar <mingo@...hat.com>,
	"H. Peter Anvin" <hpa@...or.com>, x86@...nel.org,
	leif.lindholm@...aro.org, al.stone@...aro.org, fu.wei@...aro.org,
	linux-efi@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-arm-msm@...r.kernel.org, linaro-acpi@...ts.linaro.org,
	vgandhi@...eaurora.org, Tony Luck <tony.luck@...il.com>
Subject: Re: [PATCH V2 1/3] efi: arch, x86: arch, ia64: move
 efi_mem_attributes()

On Tue, 02 Jun, at 05:09:14PM, Zhang, Jonathan Zhixiong wrote:
> Thank you for the feedback, Matt.
> 
> Given that IA64 does not set EFI_MEMMAP, it appears to me there
> are following options:
> A. Keep status quota and copy x86's efi_mem_attributes() code
> to arm64.

Let's avoid this option.

> B. In efi subsystem, provide week default efi_mem_attributes().
> In the mean time, IA64 continues to have its own implementation.

While I'm not a huge fan of using __weak this makes the most sense to me
because the alternative is to rename either the ia64 or x86
implementation and that just seems silly.

> C. Add EFI_MEMMAP support (and related bits) in IA64.

C. isn't an option because the ia64 memory map doesn't work the same way
as x86 and arm64.
 
> Which option do you prefer? Once there is a consensus, I am
> willing to submit patch accordingly for review.

Let's go with B. but please provide a comment above the weak
implementation explaining *why* it's declared as weak and that any new
architecture probably doesn't want to override it. Explain that the ia64
EFI memory map is special.

-- 
Matt Fleming, Intel Open Source Technology Center
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