Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932142AbWHVIx1 (ORCPT ); Tue, 22 Aug 2006 04:53:27 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932143AbWHVIx1 (ORCPT ); Tue, 22 Aug 2006 04:53:27 -0400 Received: from wx-out-0506.google.com ([66.249.82.228]:44659 "EHLO wx-out-0506.google.com") by vger.kernel.org with ESMTP id S932142AbWHVIx1 (ORCPT ); Tue, 22 Aug 2006 04:53:27 -0400 DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references; b=lcVHmr58TgGyP0WTg98hojqAwOLjfTgQs2gkzCe5kJ9ff03PRnVl3UsePdzDl5Bsja+BD86jMwmajq9PFv08gHhx2m96Ixl4ezWMWgbXK6W6S9wxrQXfAj0xbVG7JCik2T4T19r6JNjZr/v7xt6+qWbel60w42AyhWtM0FeLeFc= Message-ID: Date: Tue, 22 Aug 2006 17:53:26 +0900 From: "Magnus Damm" To: "Eric W. Biederman" Subject: Re: [Fastboot] [PATCH] x86_64: Reload CS when startup_64 is used. Cc: "Andi Kleen" , "Magnus Damm" , fastboot@lists.osdl.org, linux-kernel@vger.kernel.org In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <20060821095328.3132.40575.sendpatchset@cherry.local> <1156208306.21411.85.camel@localhost> <200608221003.12608.ak@suse.de> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1156 Lines: 29 Hi Eric, On 8/22/06, Eric W. Biederman wrote: > > In long mode the %cs is largely a relic. However there are a few cases > like lret where it matters that we have a valid value. Without this > patch it is possible to enter the kernel in startup_64 without setting > %cs to a valid value. With this patch we don't care what %cs value > we enter the kernel with, so long as the cs shadow register indicates > it is a privileged code segment. > > Thanks to Magnus Damm for finding this problem and posting the > first workable patch. I have moved the jump to set %cs down a > few instructions so we don't need to take an extra jump. Which > keeps the code simpler. > > Signed-of-by: Eric W. Biederman While at it, could you please fix up the purgatory code in kexec-tools to include this fix so we can boot older versions of the kernel too? Thanks, / magnus - 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/