Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751965AbdHCOth (ORCPT ); Thu, 3 Aug 2017 10:49:37 -0400 Received: from foss.arm.com ([217.140.101.70]:41518 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751134AbdHCOtc (ORCPT ); Thu, 3 Aug 2017 10:49:32 -0400 Date: Thu, 3 Aug 2017 15:49:27 +0100 From: Catalin Marinas To: Mark Rutland Cc: linux-arm-kernel@lists.infradead.org, linux-arch@vger.kernel.org, arnd@arndb.de, jiong.wang@arm.com, marc.zyngier@arm.com, yao.qi@arm.com, suzuki.poulose@arm.com, will.deacon@arm.com, linux-kernel@vger.kernel.org, Dave.Martin@arm.com, kernel-hardening@lists.openwall.com, kvmarm@lists.cs.columbia.edu, christoffer.dall@linaro.org Subject: Re: [PATCH 01/11] arm64: docs: describe ELF hwcaps Message-ID: <20170803144926.7eankdjmnyxw3zru@armageddon.cambridge.arm.com> References: <1500480092-28480-1-git-send-email-mark.rutland@arm.com> <1500480092-28480-2-git-send-email-mark.rutland@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1500480092-28480-2-git-send-email-mark.rutland@arm.com> User-Agent: NeoMutt/20170113 (1.7.2) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 511 Lines: 16 On Wed, Jul 19, 2017 at 05:01:22PM +0100, Mark Rutland wrote: > +3. The hwcaps exposed in AT_HWCAP > +--------------------------------- > + > +HWCAP_FP > + > + Functionality implied by ID_AA64PFR0_EL1.FP == 0b0000. Aren't these too restrictive? Linux would still present HWCAP_FP even when ID_AA64PFR0_EL1.FP == 1. I think we should replace the strict equal with greater than or equal, also mentioning that the field is signed (or refer to the cpuid where the sign of the fields is described). -- Catalin