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=-13.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=ham 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 49B8CC47076 for ; Fri, 21 May 2021 15:23:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2F7D2613E6 for ; Fri, 21 May 2021 15:23:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234650AbhEUPYX (ORCPT ); Fri, 21 May 2021 11:24:23 -0400 Received: from foss.arm.com ([217.140.110.172]:49722 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232199AbhEUPYX (ORCPT ); Fri, 21 May 2021 11:24:23 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id CEEB211B3; Fri, 21 May 2021 08:22:59 -0700 (PDT) Received: from e107158-lin.cambridge.arm.com (unknown [10.1.195.57]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 7F8DD3F73B; Fri, 21 May 2021 08:22:57 -0700 (PDT) Date: Fri, 21 May 2021 16:22:55 +0100 From: Qais Yousef To: Will Deacon Cc: linux-arm-kernel@lists.infradead.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, Catalin Marinas , Marc Zyngier , Greg Kroah-Hartman , Peter Zijlstra , Morten Rasmussen , Suren Baghdasaryan , Quentin Perret , Tejun Heo , Li Zefan , Johannes Weiner , Ingo Molnar , Juri Lelli , Vincent Guittot , "Rafael J. Wysocki" , kernel-team@android.com Subject: Re: [PATCH v6 02/21] arm64: Allow mismatched 32-bit EL0 support Message-ID: <20210521152255.tosr4jwok6cjg6sf@e107158-lin.cambridge.arm.com> References: <20210518094725.7701-1-will@kernel.org> <20210518094725.7701-3-will@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20210518094725.7701-3-will@kernel.org> Precedence: bulk List-ID: X-Mailing-List: linux-arch@vger.kernel.org On 05/18/21 10:47, Will Deacon wrote: > When confronted with a mixture of CPUs, some of which support 32-bit > applications and others which don't, we quite sensibly treat the system > as 64-bit only for userspace and prevent execve() of 32-bit binaries. > > Unfortunately, some crazy folks have decided to build systems like this > with the intention of running 32-bit applications, so relax our > sanitisation logic to continue to advertise 32-bit support to userspace > on these systems and track the real 32-bit capable cores in a cpumask > instead. For now, the default behaviour remains but will be tied to > a command-line option in a later patch. > > Signed-off-by: Will Deacon > --- > arch/arm64/include/asm/cpucaps.h | 3 +- Heads up. I just tried to apply this on 5.13-rc2 and it failed because cpucaps. was removed; it's autogenerated now. See commit 0c6c2d3615ef: ()"arm64: Generate cpucaps.h") Cheers -- Qais Youesf