Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754982AbYAaI2a (ORCPT ); Thu, 31 Jan 2008 03:28:30 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1764127AbYAaI1z (ORCPT ); Thu, 31 Jan 2008 03:27:55 -0500 Received: from mga02.intel.com ([134.134.136.20]:11174 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1762051AbYAaI1j (ORCPT ); Thu, 31 Jan 2008 03:27:39 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.25,283,1199692800"; d="scan'208";a="255965285" Subject: Re: [PATCH 2/5] x86: c_p_a clflush_cache_range fix From: "Huang, Ying" To: Andi Kleen Cc: Ingo Molnar , "H. Peter Anvin" , Thomas Gleixner , linux-kernel@vger.kernel.org In-Reply-To: <200801310840.25221.ak@suse.de> References: <1201764962.12950.23.camel@caritas-dev.intel.com> <200801310840.25221.ak@suse.de> Content-Type: text/plain Content-Transfer-Encoding: 7bit Date: Thu, 31 Jan 2008 16:27:53 +0800 Message-Id: <1201768073.21226.2.camel@caritas-dev.intel.com> Mime-Version: 1.0 X-Mailer: Evolution 2.12.3 X-OriginalArrivalTime: 31 Jan 2008 08:26:51.0354 (UTC) FILETIME=[076F9BA0:01C863E3] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1963 Lines: 54 On Thu, 2008-01-31 at 08:40 +0100, Andi Kleen wrote: > On Thursday 31 January 2008 08:36:02 Huang, Ying wrote: > > Because in i386 early boot stage, boot_cpu_data may be not available, > > which makes clflush_cach_range() into infinite loop, which is called > > by change_page_attr(). This patch fixes this by providing a default > > clflush_size of 64. But the better method may be providing a > > early_identify_cpu() for i386. > > There already is one. arch/x86/kernel/cpu/common.c:early_cpu_detect > Just set it to 64 there. Thanks. The following is a new patch based on your reminding. -------------------------------------------------------------------- Because in i386 early boot stage, boot_cpu_data may be not available, which makes clflush_cach_range() into infinite loop, which is called by change_page_attr(). This patch fixes this by setting boot_cpu_data.x86_clflush_size in early_cpu_detect(). Signed-off-by: Huang Ying --- arch/x86/kernel/cpu/common.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -274,8 +274,10 @@ void __init cpu_detect(struct cpuinfo_x8 if (c->x86 >= 0x6) c->x86_model += ((tfms >> 16) & 0xF) << 4; c->x86_mask = tfms & 15; - if (cap0 & (1<<19)) + if (cap0 & (1<<19)) { c->x86_cache_alignment = ((misc >> 8) & 0xff) * 8; + c->x86_clflush_size = ((misc >> 8) & 0xff) * 8; + } } } static void __cpuinit early_get_cap(struct cpuinfo_x86 *c) @@ -317,6 +319,7 @@ static void __init early_cpu_detect(void struct cpuinfo_x86 *c = &boot_cpu_data; c->x86_cache_alignment = 32; + c->x86_clflush_size = 32; if (!have_cpuid_p()) return; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/