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=-8.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 80300C56202 for ; Thu, 29 Oct 2020 00:57:57 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3AFE020796 for ; Thu, 29 Oct 2020 00:57:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728117AbgJ2A54 (ORCPT ); Wed, 28 Oct 2020 20:57:56 -0400 Received: from mail.kernel.org ([198.145.29.99]:60502 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1731584AbgJ1WRd (ORCPT ); Wed, 28 Oct 2020 18:17:33 -0400 Received: from gaia (unknown [95.145.162.19]) (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 DDEF4246F2; Wed, 28 Oct 2020 12:15:09 +0000 (UTC) Date: Wed, 28 Oct 2020 12:15:07 +0000 From: Catalin Marinas To: Will Deacon Cc: linux-arm-kernel@lists.infradead.org, linux-arch@vger.kernel.org, Marc Zyngier , Greg Kroah-Hartman , Peter Zijlstra , Morten Rasmussen , Qais Yousef , Suren Baghdasaryan , kernel-team@android.com Subject: Re: [PATCH 5/6] arm64: Advertise CPUs capable of running 32-bit applcations in sysfs Message-ID: <20201028121506.GG13345@gaia> References: <20201027215118.27003-1-will@kernel.org> <20201027215118.27003-6-will@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20201027215118.27003-6-will@kernel.org> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-arch@vger.kernel.org On Tue, Oct 27, 2020 at 09:51:17PM +0000, Will Deacon wrote: > diff --git a/Documentation/ABI/testing/sysfs-devices-system-cpu b/Documentation/ABI/testing/sysfs-devices-system-cpu > index b555df825447..19893fb8e870 100644 > --- a/Documentation/ABI/testing/sysfs-devices-system-cpu > +++ b/Documentation/ABI/testing/sysfs-devices-system-cpu > @@ -472,6 +472,14 @@ Description: AArch64 CPU registers > 'identification' directory exposes the CPU ID registers for > identifying model and revision of the CPU. > > +What: /sys/devices/system/cpu/aarch32_el0 Nitpick: should we call this aarch32_el0_present? It's not exactly present as we populate it as CPUs come online but it's closer to this mask than to the online one. > +Date: October 2020 > +Contact: Linux ARM Kernel Mailing list > +Description: Identifies the subset of CPUs in the system that can execute > + AArch32 (32-bit ARM) applications. If absent, then all or none > + of the CPUs can execute AArch32 applications and execve() will > + behave accordingly. What does "accordingly" mean? Normally, we'd get ENOEXEC but here the execve() "succeeds" followed by a SIGKILL if it ends up on the wrong CPU. -- Catalin