From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753255AbdHJQqO (ORCPT ); Thu, 10 Aug 2017 12:46:14 -0400 Received: from terminus.zytor.com ([65.50.211.136]:57151 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753094AbdHJQqL (ORCPT ); Thu, 10 Aug 2017 12:46:11 -0400 Date: Thu, 10 Aug 2017 09:42:36 -0700 From: tip-bot for Suravee Suthikulpanit Message-ID: Cc: hpa@zytor.com, bp@suse.de, linux-kernel@vger.kernel.org, mingo@kernel.org, tglx@linutronix.de, torvalds@linux-foundation.org, peterz@infradead.org, Yazen.Ghannam@amd.com, suravee.suthikulpanit@amd.com Reply-To: tglx@linutronix.de, torvalds@linux-foundation.org, mingo@kernel.org, linux-kernel@vger.kernel.org, hpa@zytor.com, bp@suse.de, suravee.suthikulpanit@amd.com, Yazen.Ghannam@amd.com, peterz@infradead.org In-Reply-To: <20170731085159.9455-2-bp@alien8.de> References: <20170731085159.9455-2-bp@alien8.de> To: linux-tip-commits@vger.kernel.org Subject: [tip:x86/cpu] x86/cpu/amd: Limit cpu_core_id fixup to families older than F17h Git-Commit-ID: b89b41d0b8414690ec0030c134b8bde209e6d06c X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: b89b41d0b8414690ec0030c134b8bde209e6d06c Gitweb: http://git.kernel.org/tip/b89b41d0b8414690ec0030c134b8bde209e6d06c Author: Suravee Suthikulpanit AuthorDate: Mon, 31 Jul 2017 10:51:58 +0200 Committer: Ingo Molnar CommitDate: Thu, 10 Aug 2017 17:37:43 +0200 x86/cpu/amd: Limit cpu_core_id fixup to families older than F17h Current cpu_core_id fixup causes downcored F17h configurations to be incorrect: NODE: 0 processor 0 core id : 0 processor 1 core id : 1 processor 2 core id : 2 processor 3 core id : 4 processor 4 core id : 5 processor 5 core id : 0 NODE: 1 processor 6 core id : 2 processor 7 core id : 3 processor 8 core id : 4 processor 9 core id : 0 processor 10 core id : 1 processor 11 core id : 2 Code that relies on the cpu_core_id, like match_smt(), for example, which builds the thread siblings masks used by the scheduler, is mislead. So, limit the fixup to pre-F17h machines. The new value for cpu_core_id for F17h and later will represent the CPUID_Fn8000001E_EBX[CoreId], which is guaranteed to be unique for each core within a socket. This way we have: NODE: 0 processor 0 core id : 0 processor 1 core id : 1 processor 2 core id : 2 processor 3 core id : 4 processor 4 core id : 5 processor 5 core id : 6 NODE: 1 processor 6 core id : 8 processor 7 core id : 9 processor 8 core id : 10 processor 9 core id : 12 processor 10 core id : 13 processor 11 core id : 14 Signed-off-by: Suravee Suthikulpanit [ Heavily massaged. ] Signed-off-by: Borislav Petkov Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Cc: Yazen Ghannam Link: http://lkml.kernel.org/r/20170731085159.9455-2-bp@alien8.de Signed-off-by: Ingo Molnar --- arch/x86/kernel/cpu/amd.c | 24 +++++++++++++++++------- 1 file changed, 17 insertions(+), 7 deletions(-) diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c index 3b9e220..82d571c 100644 --- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -298,6 +298,22 @@ static int nearby_node(int apicid) #endif /* + * Fix up cpu_core_id for pre-F17h systems to be in the + * [0 .. cores_per_node - 1] range. Not really needed but + * kept so as not to break existing setups. + */ +static void legacy_fixup_core_id(struct cpuinfo_x86 *c) +{ + u32 cus_per_node; + + if (c->x86 >= 0x17) + return; + + cus_per_node = c->x86_max_cores / nodes_per_socket; + c->cpu_core_id %= cus_per_node; +} + +/* * Fixup core topology information for * (1) AMD multi-node processors * Assumption: Number of cores in each internal node is the same. @@ -354,15 +370,9 @@ static void amd_get_topology(struct cpuinfo_x86 *c) } else return; - /* fixup multi-node processor information */ if (nodes_per_socket > 1) { - u32 cus_per_node; - set_cpu_cap(c, X86_FEATURE_AMD_DCM); - cus_per_node = c->x86_max_cores / nodes_per_socket; - - /* core id has to be in the [0 .. cores_per_node - 1] range */ - c->cpu_core_id %= cus_per_node; + legacy_fixup_core_id(c); } } #endif