From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261409AbVG3Ro4 (ORCPT ); Sat, 30 Jul 2005 13:44:56 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263085AbVG3Ro4 (ORCPT ); Sat, 30 Jul 2005 13:44:56 -0400 Received: from mailout1.vmware.com ([65.113.40.130]:15109 "EHLO mailout1.vmware.com") by vger.kernel.org with ESMTP id S261409AbVG3Roz (ORCPT ); Sat, 30 Jul 2005 13:44:55 -0400 Message-ID: <42EBBC43.3080803@vmware.com> Date: Sat, 30 Jul 2005 10:43:31 -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: Pavel Machek Cc: 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> In-Reply-To: <20050730103207.GD1942@elf.ucw.cz> Content-Type: multipart/mixed; boundary="------------030403070700070407040105" X-OriginalArrivalTime: 30 Jul 2005 17:43:31.0234 (UTC) FILETIME=[33579820:01C5952E] Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org This is a multi-part message in MIME format. --------------030403070700070407040105 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Pavel Machek wrote: >Hi! > > > >>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. >> >> > >Can we get better name, like "serialize_cpu()"? > Pavel > > No objections to changing the name by me. In fact, looks like serialize was a rather poor choice in the context of the microcode update source, since there are already references to lock based serialization right around the same code. Updated comments as well. Zach --------------030403070700070407040105 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 10:35:27.000000000 -0700 @@ -164,7 +164,8 @@ } wrmsr(MSR_IA32_UCODE_REV, 0, 0); - __asm__ __volatile__ ("cpuid" : : : "ax", "bx", "cx", "dx"); + /* see 1.07. Apprent 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 1.07. Apprent 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) { --------------030403070700070407040105--