From mboxrd@z Thu Jan 1 00:00:00 1970 Received: with ECARTIS (v1.0.0; list linux-mips); Wed, 10 Mar 2010 11:45:18 +0100 (CET) Received: from ey-out-1920.google.com ([74.125.78.146]:18729 "EHLO ey-out-1920.google.com" rhost-flags-OK-OK-OK-OK) by eddie.linux-mips.org with ESMTP id S1492161Ab0CJKpM (ORCPT ); Wed, 10 Mar 2010 11:45:12 +0100 Received: by ey-out-1920.google.com with SMTP id 13so826430eye.52 for ; Wed, 10 Mar 2010 02:45:11 -0800 (PST) Received: by 10.213.104.89 with SMTP id n25mr4887336ebo.78.1268217908122; Wed, 10 Mar 2010 02:45:08 -0800 (PST) Received: from [192.168.2.2] (ppp85-140-114-94.pppoe.mtu-net.ru [85.140.114.94]) by mx.google.com with ESMTPS id 14sm3753633ewy.10.2010.03.10.02.45.06 (version=TLSv1/SSLv3 cipher=RC4-MD5); Wed, 10 Mar 2010 02:45:06 -0800 (PST) Message-ID: <4B977815.4000703@ru.mvista.com> Date: Wed, 10 Mar 2010 13:44:37 +0300 From: Sergei Shtylyov User-Agent: Thunderbird 2.0.0.23 (Windows/20090812) MIME-Version: 1.0 To: Wu Zhangjin CC: Ralf Baechle , Greg KH , linux-mips@linux-mips.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 1/3] Loongson-2F: Flush the branch target history such as BTB and RAS References: In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Return-Path: X-Envelope-To: <"|/home/ecartis/ecartis -s linux-mips"> (uid 0) X-Orcpt: rfc822;linux-mips@linux-mips.org Original-Recipient: rfc822;linux-mips@linux-mips.org X-archive-position: 26170 X-ecartis-version: Ecartis v1.0.0 Sender: linux-mips-bounce@linux-mips.org Errors-to: linux-mips-bounce@linux-mips.org X-original-sender: sshtylyov@mvista.com Precedence: bulk X-list: linux-mips Hello. Wu Zhangjin wrote: > From: Wu Zhangjin > > As the Chapter 15: "Errata: Issue of Out-of-order in loongson"[1] shows, to > workaround the Issue of Loongson-2F，We need to do: > > "When switching from user model to kernel model, you should flush the branch > target history such as BTB and RAS." > > This patch did clear BTB(branch target buffer), forbid RAS(row address strobe) > via Loongson-2F's 64bit diagnostic register. > > [1] Chinese Version: http://www.loongson.cn/uploadfile/file/200808211 > [2] English Version of Chapter 15: > http://groups.google.com.hk/group/loongson-dev/msg/e0d2e220958f10a6?dmode=source > > Signed-off-by: Wu Zhangjin > --- > arch/mips/include/asm/stackframe.h | 19 +++++++++++++++++++ > 1 files changed, 19 insertions(+), 0 deletions(-) > > diff --git a/arch/mips/include/asm/stackframe.h b/arch/mips/include/asm/stackframe.h > index 3b6da33..b84cfda 100644 > --- a/arch/mips/include/asm/stackframe.h > +++ b/arch/mips/include/asm/stackframe.h > @@ -121,6 +121,25 @@ > .endm > #else > .macro get_saved_sp /* Uniprocessor variation */ > +#ifdef CONFIG_CPU_LOONGSON2F > + /* > + * Clear BTB(branch target buffer), forbid RAS(row address > + * strobe) No spaces before the left paren... > to workaround the Out-of-oder Issue in Loongson2F > + * via it's diagnostic register. > Only "its". > + */ > + move k0, ra > Operands misalined... WBR, Sergei