From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.6 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 14476C5519F for ; Thu, 12 Nov 2020 17:36:35 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9F23721D7F for ; Thu, 12 Nov 2020 17:36:34 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="ML1g3jZr" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726249AbgKLRgd (ORCPT ); Thu, 12 Nov 2020 12:36:33 -0500 Received: from mail.kernel.org ([198.145.29.99]:52108 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726157AbgKLRgc (ORCPT ); Thu, 12 Nov 2020 12:36:32 -0500 Received: from willie-the-truck (236.31.169.217.in-addr.arpa [217.169.31.236]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id 31764206CA; Thu, 12 Nov 2020 17:36:29 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1605202591; bh=0wdqaLJO8vq/+dObf9RCcuo7JHilHrGILJwWHpaMIAE=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=ML1g3jZrJ+S1rqnJFWA99AXd1DfIr9WbquLrJM8C7404gynzj361HwuFO/+rVFMPI Sx+GnpZi2qUNJoXZjBaJyqHqkyupowUd+P5MA1YCFBS6vCMwIvPBMScfU6DJkT3Qyy k3tWTAr+LIAcR9y6zbkr+rr/vP00z5l9Zfkvv3jo= Date: Thu, 12 Nov 2020 17:36:25 +0000 From: Will Deacon To: Qais Yousef Cc: Catalin Marinas , "linux-arm-kernel@lists.infradead.org" , "linux-arch@vger.kernel.org" , Marc Zyngier , Greg Kroah-Hartman , Peter Zijlstra , Morten Rasmussen , Suren Baghdasaryan , "kernel-team@android.com" Subject: Re: [PATCH 2/6] arm64: Allow mismatched 32-bit EL0 support Message-ID: <20201112173625.GA20000@willie-the-truck> References: <20201102114444.GC21082@gaia> <20201105213846.GA8600@willie-the-truck> <20201106125425.u6qoswsjfskyxtoo@e107158-lin.cambridge.arm.com> <20201106130007.GA10605@willie-the-truck> <20201106144835.q363ezyse4vc5kdg@e107158-lin.cambridge.arm.com> <20201109135259.GA14526@willie-the-truck> <20201111162700.p4sem2fup5qjjbqz@e107158-lin.cambridge.arm.com> <20201112102424.GB19506@willie-the-truck> <20201112115555.65sfsod6uf6xm5gy@e107158-lin.cambridge.arm.com> <20201112164943.7kdskvxcnuodphow@e107158-lin.cambridge.arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201112164943.7kdskvxcnuodphow@e107158-lin.cambridge.arm.com> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-arch@vger.kernel.org On Thu, Nov 12, 2020 at 04:49:43PM +0000, Qais Yousef wrote: > On 11/12/20 11:55, Qais Yousef wrote: > > On 11/12/20 10:24, Will Deacon wrote: > > > On Wed, Nov 11, 2020 at 04:27:00PM +0000, Qais Yousef wrote: > > > > On 11/09/20 13:52, Will Deacon wrote: > > > > > On Fri, Nov 06, 2020 at 02:48:35PM +0000, Qais Yousef wrote: > > > > > > On 11/06/20 13:00, Will Deacon wrote: > > > > > > > On Fri, Nov 06, 2020 at 12:54:25PM +0000, Qais Yousef wrote: > > > > > > > > FWIW I have my v3 over here in case it's of any help. It solves the problem of > > > > > > > > HWCAP discovery when late AArch32 CPU is booted by populating boot_cpu_date > > > > > > > > with 32bit features then. > > > > > > > > > > > > > > > > git clone https://git.gitlab.arm.com/linux-arm/linux-qy.git -b asym-aarch32-upstream-v3 origin/asym-aarch32-upstream-v3 > > > > > > > > > > > > > > Cheers, I've done something similar. I was hoping to post it today, but I've > > > > > > > been side-tracked with bug fixing this morning. The main headache I ended up > > > > > > > with was allowing late-onlining of 64-bit-only CPUs if all the boot CPUs > > > > > > > are 32-bit capable. What do you do in that case? > > > > > > > > > > > > Do you mean if CPUs 0-3 were 32bit capable and we boot with maxcpus=4 then > > > > > > attempt to bring the remaining 64bit-only cpus online later? > > > > > > > > > > Right. I think we will refuse to online them. I'll post my attempt at > > > > > handling that shortly. > > > > > > > > Sorry for the delayed response. > > > > > > > > You're right, I tried that and they refuse to come online. We missed that tbh. > > > > > > > > Haven't thought what we should do yet. I tried your v2 and it failed similarly. > > > > > > Hmm, it shouldn't do. Please could you provide the log? My hunch is that you > > > are blatting 32-bit EL1 support as well, and we can't handle a mismatch for > > > that with a late CPU. Do you know if the CPUs being integrated into these > > > broken designs have a mismatch at EL1 as well? > > > > Hmm my test could have been invalid then. We shouldn't have mismatch at EL1, > > for ease of testing I used a hacked up patch to fake asymmetry on Juno. Testing > > on FVP now, it takes time to boot up though.. > > > > Let me re-run this and get you the log from proper environment. Assuming it > > still fails. > > Still fails the same on FVP. dmesg attached. There's a splat shortly after > attempting to online CPU 4. > > # cat /sys/devices/system/cpu/online > 0-3 > # cat /sys/devices/system/cpu/aarch32_el0 > 0-3 > > Now while writing this I just realized I tell the FVP to disable aarch32 > support at EL0. So this might still make the kernel thinks there's AArch32 > support at EL1 - which seems is what makes your series get confused? | CPU features: CPU4: Detected conflict for capability 53 (32-bit EL1 Support), System: 1, CPU: 0 So we're doing the right thing here. I've already queued fixes for the splat in for-next/fixes, as it's unrelated. Will