From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1161070AbcA1LVC (ORCPT ); Thu, 28 Jan 2016 06:21:02 -0500 Received: from foss.arm.com ([217.140.101.70]:59506 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S966106AbcA1LU7 (ORCPT ); Thu, 28 Jan 2016 06:20:59 -0500 Date: Thu, 28 Jan 2016 11:20:33 +0000 From: Mark Rutland To: Will Deacon , ard.biesheuvel@linaro.org, jeremy.linton@arm.com Cc: Catalin Marinas , Feng Kan , dann frazier , Duc Dang , linux-kernel@vger.kernel.org, Loc Ho , Kumar Sankaran , linux-arm-kernel@lists.infradead.org Subject: Re: [PATCH] arm64: Disallow combination of ARCH_XGENE and 16K page size Message-ID: <20160128112033.GI17123@leverpostej> References: <1453936230-7305-1-git-send-email-dann.frazier@canonical.com> <20160128103441.GS14823@e104818-lin.cambridge.arm.com> <20160128110820.GE30928@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20160128110820.GE30928@arm.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Jan 28, 2016 at 11:08:20AM +0000, 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. > > > > > > Signed-off-by: dann frazier > > > --- > > > arch/arm64/Kconfig.platforms | 1 + > > > 1 file changed, 1 insertion(+) > > > > > > diff --git a/arch/arm64/Kconfig.platforms b/arch/arm64/Kconfig.platforms > > > index 21074f6..b241290 100644 > > > --- a/arch/arm64/Kconfig.platforms > > > +++ b/arch/arm64/Kconfig.platforms > > > @@ -133,6 +133,7 @@ config ARCH_VEXPRESS > > > > > > config ARCH_XGENE > > > bool "AppliedMicro X-Gene SOC Family" > > > + depends on !ARM64_16K_PAGES > > > help > > > 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? Yup. There are other things we could/should test, too. I believe Jeremy had a patch, but due to churn in that area it didn't get picked up. Mark.