From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932383AbbJHLLf (ORCPT ); Thu, 8 Oct 2015 07:11:35 -0400 Received: from foss.arm.com ([217.140.101.70]:33757 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932268AbbJHLLd (ORCPT ); Thu, 8 Oct 2015 07:11:33 -0400 Date: Thu, 8 Oct 2015 12:11:28 +0100 From: Catalin Marinas To: "Suzuki K. Poulose" Cc: linux-arm-kernel@lists.infradead.org, mark.rutland@arm.com, Vladimir.Murzin@arm.com, steve.capper@linaro.org, ard.biesheuvel@linaro.org, marc.zyngier@arm.com, will.deacon@arm.com, linux-kernel@vger.kernel.org, edward.nevill@linaro.org, aph@redhat.com, james.morse@arm.com, andre.przywara@arm.com, dave.martin@arm.com Subject: Re: [PATCH v2 16/22] arm64/debug: Make use of the system wide safe value Message-ID: <20151008111128.GH17192@e104818-lin.cambridge.arm.com> References: <1444064531-25607-1-git-send-email-suzuki.poulose@arm.com> <1444064531-25607-17-git-send-email-suzuki.poulose@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1444064531-25607-17-git-send-email-suzuki.poulose@arm.com> User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Oct 05, 2015 at 06:02:05PM +0100, Suzuki K. Poulose wrote: > @@ -137,13 +138,17 @@ extern struct pmu perf_ops_bp; > /* Determine number of BRP registers available. */ > static inline int get_num_brps(void) > { > - return ((read_cpuid(ID_AA64DFR0_EL1) >> 12) & 0xf) + 1; > + return 1 + > + cpuid_feature_extract_field(read_system_reg(SYS_ID_AA64DFR0_EL1), > + ID_AA64DFR0_BRPS_SHIFT); > } cpuid_feature_extract_field() is fine but we should we bother with read_system_reg vs just read_cpuid? Similar question for patch 17/22. -- Catalin