From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753302Ab0CYLGY (ORCPT ); Thu, 25 Mar 2010 07:06:24 -0400 Received: from s15228384.onlinehome-server.info ([87.106.30.177]:45525 "EHLO mail.x86-64.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751752Ab0CYLGW (ORCPT ); Thu, 25 Mar 2010 07:06:22 -0400 Date: Thu, 25 Mar 2010 12:06:49 +0100 From: Borislav Petkov To: Thomas Renninger Cc: akpm@linux-foundation.org, davej@redhat.com, linux@dominikbrodowski.net, mingo@elte.hu, hpa@zytor.com, tglx@linutronix.de, cpufreq@vger.kernel.org, x86@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 3/5] cpufreq: Add APERF/MPERF support for AMD processors Message-ID: <20100325110648.GA6060@aftab> References: <1269452783-966-1-git-send-email-bp@amd64.org> <1269452783-966-4-git-send-email-bp@amd64.org> <201003251043.04867.trenn@suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <201003251043.04867.trenn@suse.de> Organization: Advanced Micro Devices =?iso-8859-1?Q?GmbH?= =?iso-8859-1?Q?=2C_Karl-Hammerschmidt-Str=2E_34=2C_85609_Dornach_bei_M=FC?= =?iso-8859-1?Q?nchen=2C_Gesch=E4ftsf=FChrer=3A_Thomas_M=2E_McCoy=2C_Giuli?= =?iso-8859-1?Q?ano_Meroni=2C_Andrew_Bowd=2C_Sitz=3A_Dornach=2C_Gemeinde_A?= =?iso-8859-1?Q?schheim=2C_Landkreis_M=FCnchen=2C_Registergericht_M=FCnche?= =?iso-8859-1?Q?n=2C?= HRB Nr. 43632 User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Thomas Renninger Date: Thu, Mar 25, 2010 at 10:43:04AM +0100 Hi Thomas, > On Wednesday 24 March 2010 18:46:21 Borislav Petkov wrote: > > From: Mark Langsdorf > > > > Starting with model 10 of Family 0x10, AMD processors may have > > support for APERF/MPERF. Add support for identifying it and using > > it within cpufreq. Move the APERF/MPERF functions out of the > > acpi-cpufreq code and into their own file so they can easily be > > shared. > > > > Signed-off-by: Mark Langsdorf > > Signed-off-by: Borislav Petkov > > --- > > arch/x86/kernel/cpu/amd.c | 6 +++ > > arch/x86/kernel/cpu/cpufreq/Makefile | 4 +- > > arch/x86/kernel/cpu/cpufreq/acpi-cpufreq.c | 44 +----------------------- > > arch/x86/kernel/cpu/cpufreq/mperf.c | 50 ++++++++++++++++++++++++++++ > > arch/x86/kernel/cpu/cpufreq/mperf.h | 9 +++++ > > arch/x86/kernel/cpu/cpufreq/powernow-k8.c | 8 ++++ > > 6 files changed, 77 insertions(+), 44 deletions(-) > > create mode 100644 arch/x86/kernel/cpu/cpufreq/mperf.c > > create mode 100644 arch/x86/kernel/cpu/cpufreq/mperf.h > > > > diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c > > index e485825..796f662 100644 > > --- a/arch/x86/kernel/cpu/amd.c > > +++ b/arch/x86/kernel/cpu/amd.c > > @@ -537,6 +537,12 @@ static void __cpuinit init_amd(struct cpuinfo_x86 *c) > > set_cpu_cap(c, X86_FEATURE_MFENCE_RDTSC); > > } > > > > + if (c->cpuid_level >= 6) { > > + unsigned ecx = cpuid_ecx(6); > > + if (ecx & 0x01) > > + set_cpu_cap(c, X86_FEATURE_APERFMPERF); > > + } > > + > Can you put this into: > arch/x86/kernel/cpu/common.c (or wherever it fits in general x86 cpu init code) > and remove this (arch/x86/kernel/cpu/intel.c): > if (c->cpuid_level > 6) { > unsigned ecx = cpuid_ecx(6); > if (ecx & 0x01) > set_cpu_cap(c, X86_FEATURE_APERFMPERF); > } > > an x86 maintainer might want to double check, but I expect this should work > for all x86 machines? Yes, it should. However, there's the remote, far-fetched possibility that other x86 vendors besides AMD and Intel, might have/plan to have CPUID, base function 6, ECX[1] defined as a completely different feature flag. And then it becomes ugly. Besides, this is, strictly speaking, not x86 generic code but AMD- and Intel-generic (huh, is there something like that? :)) code. So, IMO, this is a judgement call based on the current settings of the duplication and bloating levels of the x86 maintainers' filters :) Let's have some more opinions, please... Thanks. -- Regards/Gruss, Boris. -- Advanced Micro Devices, Inc. Operating Systems Research Center