From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754630AbaI2OME (ORCPT ); Mon, 29 Sep 2014 10:12:04 -0400 Received: from outbound-smtp04.blacknight.com ([81.17.249.35]:54505 "EHLO outbound-smtp04.blacknight.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754595AbaI2OMB (ORCPT ); Mon, 29 Sep 2014 10:12:01 -0400 Message-ID: <542968AE.3090407@nexus-software.ie> Date: Mon, 29 Sep 2014 15:11:58 +0100 From: "Bryan O'Donoghue" User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.1.2 MIME-Version: 1.0 To: Dave Jones , tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, x86@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/1] x86: Quark: Enable correct cache size/type reporting References: <1411956372-16469-1-git-send-email-pure.logic@nexus-software.ie> <1411956372-16469-2-git-send-email-pure.logic@nexus-software.ie> <20140929134008.GA7764@redhat.com> In-Reply-To: <20140929134008.GA7764@redhat.com> Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 29/09/14 14:40, Dave Jones wrote: > On Mon, Sep 29, 2014 at 03:06:12AM +0100, Bryan O'Donoghue wrote: > > Quark X1000 lacks cpuid(4). It has cpuid(2) but returns no cache > > descriptors we can work with i.e. cpuid(2) returns > > eax=0x00000001 ebx=0x00000000 ecx=0x00000000 edx=0x00000000 > > > > Quark X1000 contains a 16k 4-way set associative unified L1 cache > > with 256 sets > > > > This patch emulates cpuid(4) in a similar way to other x86 > > processors like AMDs which don't support cpuid(4). The Quark code > > is based on the existing AMD code. > > This looks like it would work, but I wonder if it would be a lot > simpler to do something like what we do in centaur_size_cache() > which is the other case I recall where we had to override > the CPUs definition of cache size. Hi Dave. It's working alright :) My feeling is that we'll probably end up with less changes/new code taking the approach of quirking.