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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C33EAC2BA4C for ; Wed, 26 Jan 2022 10:36:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238450AbiAZKgv (ORCPT ); Wed, 26 Jan 2022 05:36:51 -0500 Received: from foss.arm.com ([217.140.110.172]:58514 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232441AbiAZKgu (ORCPT ); Wed, 26 Jan 2022 05:36:50 -0500 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 6AD6F1FB; Wed, 26 Jan 2022 02:36:50 -0800 (PST) Received: from bogus (unknown [10.57.39.189]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id AE2C53F766; Wed, 26 Jan 2022 02:36:48 -0800 (PST) Date: Wed, 26 Jan 2022 10:36:14 +0000 From: Sudeep Holla To: Kohei Tarumizu Cc: catalin.marinas@arm.com, will@kernel.org, tglx@linutronix.de, Sudeep Holla , mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 5/8] arm64: Create cache sysfs directory without ACPI PPTT for hardware prefetch control Message-ID: <20220126103614.pcrcuc2kzklkq3xa@bogus> References: <20220125071414.811344-1-tarumizu.kohei@fujitsu.com> <20220125071414.811344-6-tarumizu.kohei@fujitsu.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20220125071414.811344-6-tarumizu.kohei@fujitsu.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, Jan 25, 2022 at 04:14:11PM +0900, Kohei Tarumizu wrote: > This patch will create a cache sysfs directory without ACPI PPTT if > the CONFIG_HWPF_CONTROL is true. > > Hardware prefetch control driver need cache sysfs directory and cache > level/type information. In ARM processor, these information can be > obtained from the register even without PPTT. Therefore, we set the > cpu_map_populated to true to create cache sysfs directory if the > machine doesn't have PPTT. I am assuming this is ACPI enabled system. This looks bit hacky in my opinion. Before I explore better way of adding it, I would like to check if you have explored ways to add PPTT reading these registers from UEFI/EDK2 as PPTT has other topology information which you will need anyways. That would simplify handling of these cacheinfo sysfs in the kernel. Let me know what are your thoughts ? -- Regards, Sudeep