Path: csiph.com!news.mixmin.net!aioe.org!gothmog.csi.it!bofh.it!news.nic.it!robomod From: Ard Biesheuvel Newsgroups: linux.kernel Subject: Re: [PATCH] arm64: Disallow combination of ARCH_XGENE and 16K page size Date: Thu, 28 Jan 2016 12:40:03 +0100 Message-ID: References: Dkim-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=lfNDCYRGckjzunacgnEkPMirz7k4I2onruTyX3I9oNY=; b=f3Pk5fiir6WFBD1j3nH8bOql7hKBn9ZIcTZhLdTs1pY2A+p8AFHT9upwuYkwpbgZ+N cYBOhFdO24lc7bAnRQg/J6jZKijSwG77lH4Keoc10Sr/n6JjNAdiKt7ieHd8tGSK/P1c H9L3OT8lXbTUaAjEQ92izgLqUwVEP9xDhMNqA= X-Google-Dkim-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:mime-version:in-reply-to:references:date :message-id:subject:from:to:cc:content-type; bh=lfNDCYRGckjzunacgnEkPMirz7k4I2onruTyX3I9oNY=; b=dpVGXdh77wSJJatAM1sAof/hSBZH8qd6kMAMgVLTgW9gahGnKztFMv31b1jtDT02vE CZS7awIIUWGdYTqNLRLjdLgsPYNi60FCM5r6zJaxBWCvCiYwWEr7bThR3ECsxDynrDMn neTqvB+/L38cS9QlpwBqXNTxYRZKNSqJhcrxnVU99CrJZbCZxSg/FVUPIVa6Jr4jHnYf LHXdfE/010CgzZY4hWmBuV322a+orx8/2NPlYJOchURhOlvRhDETgdAJnA0zFDu7A/HP bu7qwFZLJYYm843uC8QX8ij4Q/GFoRXRcdCQRunfTwn0e60f3HQ+AJEvYMgfs9WlmVpE orOw== X-Gm-Message-State: AG10YOTHQ/w4nzJ39Qel/SGWQkGBL1Ei1XvKea4NhXvpX6xQTtRVZcu4NNl3rOX931gNmoqM+wxoTraYUw1U7tzO MIME-Version: 1.0 X-Received: by 10.50.134.41 with SMTP id ph9mr2578995igb.71.1453980644480; Thu, 28 Jan 2016 03:30:44 -0800 (PST) Content-Type: text/plain; charset=UTF-8 Sender: robomod@news.nic.it List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Approved: robomod@news.nic.it Lines: 37 Organization: linux.* mail to news gateway X-Original-Cc: Will Deacon , Catalin Marinas , Feng Kan , dann frazier , Duc Dang , "linux-kernel@vger.kernel.org" , Loc Ho , Kumar Sankaran , "linux-arm-kernel@lists.infradead.org" X-Original-Date: Thu, 28 Jan 2016 12:30:44 +0100 X-Original-Message-ID: X-Original-References: <1453936230-7305-1-git-send-email-dann.frazier@canonical.com> <20160128103441.GS14823@e104818-lin.cambridge.arm.com> <20160128110820.GE30928@arm.com> <56A9FB15.1080203@arm.com> X-Original-Sender: linux-kernel-owner@vger.kernel.org Xref: csiph.com linux.kernel:1320595 On 28 January 2016 at 12:27, Suzuki K. Poulose 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.