From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933129AbcFBXGU (ORCPT ); Thu, 2 Jun 2016 19:06:20 -0400 Received: from mga14.intel.com ([192.55.52.115]:63083 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932166AbcFBXGT (ORCPT ); Thu, 2 Jun 2016 19:06:19 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.26,408,1459839600"; d="scan'208";a="994178010" From: Andi Kleen To: x86@kernel.org Cc: linux-kernel@vger.kernel.org, Andi Kleen , hmh@hmh.eng.br Subject: [PATCH] x86: Report Intel platform_id in /proc/cpuinfo Date: Thu, 2 Jun 2016 08:51:27 -0700 Message-Id: <20160602155127.76987-1-andi@firstfloor.org> X-Mailer: git-send-email 2.8.3 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Andi Kleen We have a need to distinguish systems based on their platform ID. For example this is useful to distinguish systems with L4 cache versus ones without. There is a 3 bit identifier (also called processor flags) in the IA32_PLATFORM_ID MSR that can give a more fine grained identification of the CPU than just the model number/stepping. IA32_PLATFORM_ID is architectural. The processor flags are already used in the microcode driver. The MSR can be also accessed through /dev/cpu/*/msr, but that requires root and is awkward. This patch just exports the value retrieved by the microcode driver in /proc/cpuinfo. If the microcode driver is disabled it won't be shown, but that seems reasonable. v2: Handle 0 platform_id. Fix commit message. Cc: hmh@hmh.eng.br Signed-off-by: Andi Kleen --- arch/x86/include/asm/processor.h | 2 ++ arch/x86/kernel/cpu/microcode/intel.c | 2 ++ arch/x86/kernel/cpu/proc.c | 2 ++ 3 files changed, 6 insertions(+) diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index 20c11d1..270209c 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -136,6 +136,8 @@ struct cpuinfo_x86 { /* Index into per_cpu list: */ u16 cpu_index; u32 microcode; + u32 platform_id; + u8 has_platform_id; }; #define X86_VENDOR_INTEL 0 diff --git a/arch/x86/kernel/cpu/microcode/intel.c b/arch/x86/kernel/cpu/microcode/intel.c index ee81c54..bcd3f59 100644 --- a/arch/x86/kernel/cpu/microcode/intel.c +++ b/arch/x86/kernel/cpu/microcode/intel.c @@ -812,6 +812,8 @@ static int collect_cpu_info(int cpu_num, struct cpu_signature *csig) /* get processor flags from MSR 0x17 */ rdmsr(MSR_IA32_PLATFORM_ID, val[0], val[1]); csig->pf = 1 << ((val[1] >> 18) & 7); + cpu_data(cpu_num).platform_id = (val[1] >> 18) & 7; + cpu_data(cpu_num).has_platform_id = true; } csig->rev = c->microcode; diff --git a/arch/x86/kernel/cpu/proc.c b/arch/x86/kernel/cpu/proc.c index 18ca99f..5345d50 100644 --- a/arch/x86/kernel/cpu/proc.c +++ b/arch/x86/kernel/cpu/proc.c @@ -76,6 +76,8 @@ static int show_cpuinfo(struct seq_file *m, void *v) seq_puts(m, "stepping\t: unknown\n"); if (c->microcode) seq_printf(m, "microcode\t: 0x%x\n", c->microcode); + if (c->has_platform_id) + seq_printf(m, "platform_id\t: %d\n", c->platform_id); if (cpu_has(c, X86_FEATURE_TSC)) { unsigned int freq = cpufreq_quick_get(cpu); -- 2.8.3