From patchwork Thu May 8 16:44:20 2014 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Suravee Suthikulpanit X-Patchwork-Id: 347131 Return-Path: X-Original-To: incoming@patchwork.ozlabs.org Delivered-To: patchwork-incoming@bilbo.ozlabs.org Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by ozlabs.org (Postfix) with ESMTP id BB8AF140098 for ; Fri, 9 May 2014 02:46:00 +1000 (EST) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755301AbaEHQpa (ORCPT ); Thu, 8 May 2014 12:45:30 -0400 Received: from mail-bl2lp0206.outbound.protection.outlook.com ([207.46.163.206]:10625 "EHLO na01-bl2-obe.outbound.protection.outlook.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755102AbaEHQpB (ORCPT ); Thu, 8 May 2014 12:45:01 -0400 Received: from BY2PR02CA016.namprd02.prod.outlook.com (10.242.234.144) by BY2PR02MB124.namprd02.prod.outlook.com (10.242.43.149) with Microsoft SMTP Server (TLS) id 15.0.934.12; Thu, 8 May 2014 16:44:41 +0000 Received: from BN1BFFO11FD035.protection.gbl (2a01:111:f400:7c10::1:193) by BY2PR02CA016.outlook.office365.com (2a01:111:e400:2c2c::16) with Microsoft SMTP Server (TLS) id 15.0.939.12 via Frontend Transport; Thu, 8 May 2014 16:44:41 +0000 Received: from atltwp01.amd.com (165.204.84.221) by BN1BFFO11FD035.mail.protection.outlook.com (10.58.144.98) with Microsoft SMTP Server id 15.0.929.8 via Frontend Transport; Thu, 8 May 2014 16:44:40 +0000 X-WSS-ID: 0N59L6E-07-DX6-02 X-M-MSG: Received: from satlvexedge01.amd.com (satlvexedge01.amd.com [10.177.96.28]) (using TLSv1 with cipher AES128-SHA (128/128 bits)) (No client certificate requested) by atltwp01.amd.com (Axway MailGate 5.3.1) with ESMTPS id 29483CAE63A; Thu, 8 May 2014 11:44:38 -0500 (CDT) Received: from SATLEXDAG06.amd.com (10.181.40.13) by satlvexedge01.amd.com (10.177.96.28) with Microsoft SMTP Server (TLS) id 14.2.328.9; Thu, 8 May 2014 11:45:17 -0500 Received: from ssuthiku-fedora-lt.amd.com (10.180.168.240) by satlexdag06.amd.com (10.181.40.13) with Microsoft SMTP Server id 14.2.328.9; Thu, 8 May 2014 12:44:39 -0400 From: To: , CC: , Aravind Gopalakrishnan , Borislav Petkov , "Robert Richter" , Daniel J Blueman , Andreas Herrmann , Myron Stowe , Suravee Suthikulpanit Subject: [PATCH V4 3/4] ACPI/PCI: Warn if we have to "guess" host bridge node information Date: Thu, 8 May 2014 11:44:20 -0500 Message-ID: <1399567461-15928-4-git-send-email-suravee.suthikulpanit@amd.com> X-Mailer: git-send-email 1.9.0 In-Reply-To: <1399567461-15928-1-git-send-email-suravee.suthikulpanit@amd.com> References: <1399567461-15928-1-git-send-email-suravee.suthikulpanit@amd.com> MIME-Version: 1.0 X-EOPAttributedMessage: 0 X-Forefront-Antispam-Report: CIP:165.204.84.221; CTRY:US; IPV:NLI; IPV:NLI; EFV:NLI; SFV:NSPM; SFS:(10009001)(6009001)(428001)(46034005)(199002)(189002)(33646001)(84676001)(2009001)(99396002)(80022001)(4396001)(50466002)(50226001)(68736004)(48376002)(97736001)(50986999)(64706001)(19580395003)(87286001)(62966002)(20776003)(19580405001)(76176999)(87936001)(83322001)(89996001)(83072002)(85852003)(53416003)(93916002)(575784001)(46102001)(86362001)(92566001)(86152002)(47776003)(21056001)(77982001)(101416001)(74662001)(77156001)(36756003)(81542001)(31966008)(76482001)(15975445006)(88136002)(44976005)(92726001)(79102001)(81342001)(74502001); DIR:OUT; SFP:1101; SCL:1; SRVR:BY2PR02MB124; H:atltwp01.amd.com; FPR:; MLV:sfv; PTR:InfoDomainNonexistent; A:1; MX:1; LANG:en; X-Forefront-PRVS: 0205EDCD76 Received-SPF: None (: amd.com does not designate permitted sender hosts) Authentication-Results: spf=none (sender IP is 165.204.84.221) smtp.mailfrom=Suravee.Suthikulpanit@amd.com; X-OriginatorOrg: amd4.onmicrosoft.com Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@vger.kernel.org From: Myron Stowe The vast majority of platforms are not supplying ACPI _PXM (proximity) information corresponding to host bridge (PNP0A03/PNP0A08) devices resulting in sysfs "numa_node" values of -1 (NUMA_NO_NODE) [1]: # for i in /sys/devices/pci0000\:00/*/numa_node; do cat $i; done | uniq -1 # find /sys/ -name "numa_node" | while read fname; do cat $fname; \ done | uniq -1 AMD based platforms provide a fall-back for this situation via amd_bus.c. These platforms snoop out the information by directly reading specific registers from the Northbridge and caching them via 'alloc_pci_root_info'. Later during boot processing when host bridges are discovered - 'pci_acpi_scan_root' - the kernel looks for their corresponding ACPI _PXM method - drivers/acpi/numa.c::acpi_get_node(). If the BIOS supplied a _PXM method then that node (proximity) value is associated. If the BIOS did not supply a _PXM method *and* the platform is AMD based, the fall-back cached values obtained directly from the Northbridge are used; otherwise, "NUMA_NO_NODE" is associated. There are a number of issues with this fall-back mechanism the most notable being that amd_bus.c extracts a 3-bit number from a CPU register and uses it as the node number. The node numbers used by Linux are logical and there's no reason they need to be identical to settings in the CPU registers. So if we have some node information obtained in the normal way (from _PXM, SLIT, SRAT, etc.) and some from amd_bus.c, there's no reason to believe they will be compatible. This patch warns when this situation occurs: pci_root PNP0A08:00: [Firmware Bug]: no _PXM; falling back to node 0 from hardware (may be inconsistent with ACPI node numbers) [1] https://bugzilla.kernel.org/show_bug.cgi?id=72051 Signed-off-by: Myron Stowe Signed-off-by: Suravee Suthikulpanit --- arch/x86/pci/acpi.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/arch/x86/pci/acpi.c b/arch/x86/pci/acpi.c index 01edac6..5075371 100644 --- a/arch/x86/pci/acpi.c +++ b/arch/x86/pci/acpi.c @@ -489,8 +489,12 @@ struct pci_bus *pci_acpi_scan_root(struct acpi_pci_root *root) } node = acpi_get_node(device->handle); - if (node == NUMA_NO_NODE) + if (node == NUMA_NO_NODE) { node = x86_pci_root_bus_node(busnum); + if (node != 0 && node != NUMA_NO_NODE) + dev_info(&device->dev, FW_BUG "no _PXM; falling back to node %d from hardware (may be inconsistent with ACPI node numbers)\n", + node); + } if (node != NUMA_NO_NODE && !node_online(node)) node = NUMA_NO_NODE;