Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756263AbcLALPo (ORCPT ); Thu, 1 Dec 2016 06:15:44 -0500 Received: from mail.skyhub.de ([78.46.96.112]:37657 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755492AbcLALPl (ORCPT ); Thu, 1 Dec 2016 06:15:41 -0500 Date: Thu, 1 Dec 2016 12:15:39 +0100 From: Borislav Petkov To: Thomas Gleixner Cc: Peter Zijlstra , Andy Lutomirski , x86@kernel.org, One Thousand Gnomes , "linux-kernel@vger.kernel.org" , Brian Gerst , Matthew Whitehead , Henrique de Moraes Holschuh , Denys Vlasenko , "H . Peter Anvin" , Josh Poimboeuf , Linus Torvalds Subject: [PATCH] x86/CPU: Add X86_FEATURE_CPUID Message-ID: <20161201111539.xsvvcymbb2lvqyvb@pd.tnic> References: <56690623af05784f41a4efbe1b25b1e2c43fdefb.1480536936.git.luto@kernel.org> <20161201055350.GH3092@twins.programming.kicks-ass.net> <20161201090211.nrlyjt5uklcva3pd@pd.tnic> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: User-Agent: NeoMutt/20161014 (1.7.1) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2480 Lines: 71 On Thu, Dec 01, 2016 at 11:07:21AM +0100, Thomas Gleixner wrote: > Yes, that makes a lot of sense. Here it is: --- From: Borislav Petkov Date: Thu, 1 Dec 2016 12:11:37 +0100 Subject: [PATCH] x86/CPU: Add X86_FEATURE_CPUID Add a synthetic CPUID flag denoting whether the CPU sports the CPUID instruction or not. This will come useful later when accomodating CPUID-less CPUs. Signed-off-by: Borislav Petkov --- arch/x86/include/asm/cpufeatures.h | 2 +- arch/x86/kernel/cpu/common.c | 7 ++++--- 2 files changed, 5 insertions(+), 4 deletions(-) diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h index 53e27a12ceb6..cb49dd31c3b2 100644 --- a/arch/x86/include/asm/cpufeatures.h +++ b/arch/x86/include/asm/cpufeatures.h @@ -100,7 +100,7 @@ #define X86_FEATURE_XTOPOLOGY ( 3*32+22) /* cpu topology enum extensions */ #define X86_FEATURE_TSC_RELIABLE ( 3*32+23) /* TSC is known to be reliable */ #define X86_FEATURE_NONSTOP_TSC ( 3*32+24) /* TSC does not stop in C states */ -/* free, was #define X86_FEATURE_CLFLUSH_MONITOR ( 3*32+25) * "" clflush reqd with monitor */ +#define X86_FEATURE_CPUID ( 3*32+25) /* CPU has CPUID instruction itself */ #define X86_FEATURE_EXTD_APICID ( 3*32+26) /* has extended APICID (8 bits) */ #define X86_FEATURE_AMD_DCM ( 3*32+27) /* multi-node processor */ #define X86_FEATURE_APERFMPERF ( 3*32+28) /* APERFMPERF */ diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index 90c007447507..8dcdcdeec569 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -800,14 +800,12 @@ static void __init early_identify_cpu(struct cpuinfo_x86 *c) memset(&c->x86_capability, 0, sizeof c->x86_capability); c->extended_cpuid_level = 0; - if (!have_cpuid_p()) - identify_cpu_without_cpuid(c); - /* cyrix could have cpuid enabled via c_identify()*/ if (have_cpuid_p()) { cpu_detect(c); get_cpu_vendor(c); get_cpu_cap(c); + setup_force_cpu_cap(X86_FEATURE_CPUID); if (this_cpu->c_early_init) this_cpu->c_early_init(c); @@ -817,6 +815,9 @@ static void __init early_identify_cpu(struct cpuinfo_x86 *c) if (this_cpu->c_bsp_init) this_cpu->c_bsp_init(c); + } else { + identify_cpu_without_cpuid(c); + setup_clear_cpu_cap(X86_FEATURE_CPUID); } setup_force_cpu_cap(X86_FEATURE_ALWAYS); -- 2.10.0 -- Regards/Gruss, Boris. Good mailing practices for 400: avoid top-posting and trim the reply.