Re: [PATCH] arm64: Disallow combination of ARCH_XGENE and 16K page size

From: Suzuki K. Poulose
Date: Thu Jan 28 2016 - 06:27:26 EST


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


Thanks
Suzuki