Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1758518AbaGOJD2 (ORCPT ); Tue, 15 Jul 2014 05:03:28 -0400 Received: from mail.active-venture.com ([67.228.131.205]:50267 "EHLO mail.active-venture.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751256AbaGOJDZ (ORCPT ); Tue, 15 Jul 2014 05:03:25 -0400 X-Originating-IP: 108.223.40.66 Message-ID: <53C4EE5C.5020407@roeck-us.net> Date: Tue, 15 Jul 2014 02:03:24 -0700 From: Guenter Roeck User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.6.0 MIME-Version: 1.0 To: Clemens Ladisch CC: Aravind Gopalakrishnan , Borislav Petkov , jdelvare@suse.de, rdunlap@infradead.org, bhelgaas@google.com, lm-sensors@lm-sensors.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pci@vger.kernel.org Subject: Re: [PATCH] hwmon, k10temp: Add support for AMD F15h M60h processor References: <1405369388-12729-1-git-send-email-Aravind.Gopalakrishnan@amd.com> <20140714195128.GA25124@pd.tnic> <53C43BDF.2070403@ladisch.de> <20140714203336.GA30926@roeck-us.net> <53C4DB2D.80406@ladisch.de> In-Reply-To: <53C4DB2D.80406@ladisch.de> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 07/15/2014 12:41 AM, Clemens Ladisch wrote: > Guenter Roeck wrote: >> On Mon, Jul 14, 2014 at 10:21:51PM +0200, Clemens Ladisch wrote: >>> Borislav Petkov wrote: >>>> On Mon, Jul 14, 2014 at 03:23:08PM -0500, Aravind Gopalakrishnan wrote: >>>>> + if (boot_cpu_data.x86 == 0x15 && boot_cpu_data.x86_model == 0x60) { >>>>> + pci_bus_write_config_dword(pdev->bus, PCI_DEVFN(0, 0), >>>>> + NB_SMU_IND_ADDR, IND_ADDR_OFFSET); >>>>> + pci_bus_read_config_dword(pdev->bus, PCI_DEVFN(0, 0), >>>>> + NB_SMU_IND_DATA, ®val); >>> >>> How do you prevent races with any other code that accesses some indirect >>> register? >>> >> I just wanted to ask exactly the same question. I think this will need >> locking. > > If there actually is any other code; these indirect SMU registers appear > to be mostly undocumented and to be intended to be used by the BIOS. > (Which makes me wonder why the temperature sensor was moved there.) > Scary. Does that mean there is a chance they may get used through ACPI ? > Anyway, if a lock is needed, it looks as if it could go into a helper > function such as "amd_nb_smu_ind_read()" in arch/x86/kernel/amd_nb.c. > Yes, something like that. Guenter -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/