From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263090AbVG3SAm (ORCPT ); Sat, 30 Jul 2005 14:00:42 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263069AbVG3R6f (ORCPT ); Sat, 30 Jul 2005 13:58:35 -0400 Received: from mailout1.vmware.com ([65.113.40.130]:36869 "EHLO mailout1.vmware.com") by vger.kernel.org with ESMTP id S263089AbVG3R5O (ORCPT ); Sat, 30 Jul 2005 13:57:14 -0400 Message-ID: <42EBBF26.3070101@vmware.com> Date: Sat, 30 Jul 2005 10:55:50 -0700 From: Zachary Amsden User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.2) Gecko/20040803 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Zwane Mwaikambo Cc: Pavel Machek , akpm@osdl.org, chrisl@vmware.com, davej@codemonkey.org.uk, hpa@zytor.com, linux-kernel@vger.kernel.org, pratap@vmware.com, Riley@Williams.Name Subject: Re: [PATCH] 2/6 i386 serialize-msr References: <200507300404.j6U44GSC005922@zach-dev.vmware.com> <20050730103207.GD1942@elf.ucw.cz> <42EBBC43.3080803@vmware.com> In-Reply-To: Content-Type: multipart/mixed; boundary="------------090503070909010902020205" X-OriginalArrivalTime: 30 Jul 2005 17:55:48.0718 (UTC) FILETIME=[EAEAB8E0:01C5952F] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org This is a multi-part message in MIME format. --------------090503070909010902020205 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit 'Apparently' I need to make some coffee :) Zwane Mwaikambo wrote: > wrmsr(MSR_IA32_UCODE_REV, 0, 0); >- __asm__ __volatile__ ("cpuid" : : : "ax", "bx", "cx", "dx"); >+ /* see 1.07. Apprent chip bug */ >+ serialize_cpu(); > >1.07 in which document? Also, please just spell 'apparent' correctly, >saving 1 byte really just looks lazy. > > > --------------090503070909010902020205 Content-Type: text/plain; name="serialize-msr" Content-Transfer-Encoding: 7bit Content-Disposition: inline; filename="serialize-msr" i386 arch cleanup. Introduce the serialize macro to serialize processor state. Why the microcode update needs it I am not quite sure, since wrmsr() is already a serializing instruction, but it is a microcode update, so I will keep the semantic the same, since this could be a timing workaround. As far as I can tell, this has always been there since the original microcode update source. Signed-off-by: Zachary Amsden Index: linux-2.6.13/arch/i386/kernel/microcode.c =================================================================== --- linux-2.6.13.orig/arch/i386/kernel/microcode.c 2005-07-29 15:26:04.000000000 -0700 +++ linux-2.6.13/arch/i386/kernel/microcode.c 2005-07-30 10:55:02.000000000 -0700 @@ -164,7 +164,8 @@ } wrmsr(MSR_IA32_UCODE_REV, 0, 0); - __asm__ __volatile__ ("cpuid" : : : "ax", "bx", "cx", "dx"); + /* see notes above for revision 1.07. Apparent chip bug */ + serialize_cpu(); /* get the current revision from MSR 0x8B */ rdmsr(MSR_IA32_UCODE_REV, val[0], uci->rev); pr_debug("microcode: collect_cpu_info : sig=0x%x, pf=0x%x, rev=0x%x\n", @@ -377,7 +378,9 @@ (unsigned long) uci->mc->bits >> 16 >> 16); wrmsr(MSR_IA32_UCODE_REV, 0, 0); - __asm__ __volatile__ ("cpuid" : : : "ax", "bx", "cx", "dx"); + /* see notes above for revision 1.07. Apparent chip bug */ + serialize_cpu(); + /* get the current revision from MSR 0x8B */ rdmsr(MSR_IA32_UCODE_REV, val[0], val[1]); Index: linux-2.6.13/include/asm-i386/processor.h =================================================================== --- linux-2.6.13.orig/include/asm-i386/processor.h 2005-07-29 15:26:53.000000000 -0700 +++ linux-2.6.13/include/asm-i386/processor.h 2005-07-30 10:32:44.000000000 -0700 @@ -277,6 +277,11 @@ outb((data), 0x23); \ } while (0) +static inline void serialize_cpu(void) +{ + __asm__ __volatile__ ("cpuid" : : : "ax", "bx", "cx", "dx"); +} + static inline void __monitor(const void *eax, unsigned long ecx, unsigned long edx) { --------------090503070909010902020205--