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=-17.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=unavailable 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 CBA28C47084 for ; Mon, 24 May 2021 20:21:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A80ED6140A for ; Mon, 24 May 2021 20:21:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233399AbhEXUXX (ORCPT ); Mon, 24 May 2021 16:23:23 -0400 Received: from mail.kernel.org ([198.145.29.99]:49010 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233009AbhEXUXW (ORCPT ); Mon, 24 May 2021 16:23:22 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 46E6B611B0; Mon, 24 May 2021 20:21:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1621887713; bh=6RQbeZvmHXBMt1SBEvj3/LaSGxCxDFKh6HhXV2ArOG8=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=lrk3isTbZPPXvOC+CovDArTMGcqXbhESJwjjvs5Lg3lcjHy0br1AINvTzwqRGHVie PGiNFnx/d8ZMAkTENyirJgidZ1KLVN/daTrLjqJ2yjOAxDezC8TOEC0LP7t1242mcV irhl2pgdxhRavUJ4MOcibx3NQJ0kSaHkEyS6Yo0gpzK9oB8pU9l/tXTbR9M5Qe6Elz 4bRHwxSIaWtVoKwjqQx9q0IqOn2p7LKV73bMX4s03AWvfx2vObgEmXCCzGcWKi/qJX TH3giUR/SK5oonVkFButmNZ9rWR7o0tA39JRRl/jaEWeguI99KwwCP5YQ73RzZ0Bo1 paS9ftr+WVSJg== Date: Mon, 24 May 2021 21:21:47 +0100 From: Will Deacon To: Qais Yousef 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: <20210524202146.GC15545@willie-the-truck> References: <20210518094725.7701-1-will@kernel.org> <20210518094725.7701-3-will@kernel.org> <20210521152255.tosr4jwok6cjg6sf@e107158-lin.cambridge.arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210521152255.tosr4jwok6cjg6sf@e107158-lin.cambridge.arm.com> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, May 21, 2021 at 04:22:55PM +0100, Qais Yousef wrote: > 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") Yup, cheers. I'll sort that out once we're at the stage where we're merging patches. Will