From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751689AbdBEKur (ORCPT ); Sun, 5 Feb 2017 05:50:47 -0500 Received: from mail.skyhub.de ([78.46.96.112]:37375 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751261AbdBEKuq (ORCPT ); Sun, 5 Feb 2017 05:50:46 -0500 From: Borislav Petkov To: X86 ML Cc: LKML Subject: [PATCH 2/2] x86/CPU/AMD: Fix Zen SMT topology Date: Sun, 5 Feb 2017 11:50:22 +0100 Message-Id: <20170205105022.8705-2-bp@alien8.de> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20170205105022.8705-1-bp@alien8.de> References: <20170205105022.8705-1-bp@alien8.de> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Yazen Ghannam After a33d331761bc ("x86/CPU/AMD: Fix Bulldozer topology"), SMT scheduling topology for Fam17h systems is broken because the ThreadId is included in the ApicId when SMT is enabled. So, without further decoding cpu_core_id is unique for each thread rather than the same for threads on the same core. This didn't affect systems with SMT disabled. Make cpu_core_id be what it is defined to be. Signed-off-by: Yazen Ghannam Signed-off-by: Borislav Petkov Cc: # 4.9 --- arch/x86/kernel/cpu/amd.c | 7 +++++++ 1 file changed, 7 insertions(+) diff --git a/arch/x86/kernel/cpu/amd.c b/arch/x86/kernel/cpu/amd.c index 8eda008c68ed..4e95b2e0d95f 100644 --- a/arch/x86/kernel/cpu/amd.c +++ b/arch/x86/kernel/cpu/amd.c @@ -319,6 +319,13 @@ static void amd_get_topology(struct cpuinfo_x86 *c) if (c->x86 == 0x15) c->cu_id = ebx & 0xff; + if (c->x86 >= 0x17) { + c->cpu_core_id = ebx & 0xff; + + if (smp_num_siblings > 1) + c->x86_max_cores /= smp_num_siblings; + } + /* * We may have multiple LLCs if L3 caches exist, so check if we * have an L3 cache by looking at the L3 cache CPUID leaf. -- 2.11.0