linux-kernel - Re: [PATCH] arm64: Disallow combination of ARCH

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Date:	Thu, 28 Jan 2016 12:30:44 +0100
From:	Ard Biesheuvel <ard.biesheuvel@...aro.org>
To:	"Suzuki K. Poulose" <Suzuki.Poulose@....com>
Cc:	Will Deacon <will.deacon@....com>,
	Catalin Marinas <catalin.marinas@....com>,
	Feng Kan <fkan@....com>,
	dann frazier <dann.frazier@...onical.com>,
	Duc Dang <dhdang@....com>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	Loc Ho <lho@....com>, Kumar Sankaran <ksankaran@....com>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH] arm64: Disallow combination of ARCH_XGENE and 16K page size

On 28 January 2016 at 12:27, Suzuki K. Poulose <Suzuki.Poulose@....com> wrote:
> On 28/01/16 11:08, Will Deacon wrote:
>>
>> On Thu, Jan 28, 2016 at 10:34:41AM +0000, Catalin Marinas wrote:
>>>
>>> On Wed, Jan 27, 2016 at 04:10:30PM -0700, dann frazier wrote:
>>>>
>>>> 16K page size is an optional feature of the architecture, and is not
>>>> supported by the X-Gene SoC family.
>
>
>   This enables support for AppliedMicro X-Gene SOC Family
>>>
>>>
>>> This would be the case on Juno as well. But maybe at some point the
>>> X-Gene family would gain a CPU with such support.
>>>
>>> Anyway, I would rather make 16K pages depend on EXPERT, make it a bit
>>> harder to enable. We've had a few questions recently about enabling it
>>> on CPUs that don't have such feature.
>>
>>
>> I thought there was also a suggestion that we could fail gracefully in
>> the EFI stub if we detected an unsupported page size?
>
>
> Yes, there was. But then it was also recommended [1] to add a new stubbed
> function
> for both arm & arm64, where it got lost. May be we should revive it.
>
> https://lkml.org/lkml/2015/10/15/489
>

I can pick this up

-- 
Ard.