Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753370AbZA0F6P (ORCPT ); Tue, 27 Jan 2009 00:58:15 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751702AbZA0F57 (ORCPT ); Tue, 27 Jan 2009 00:57:59 -0500 Received: from rv-out-0506.google.com ([209.85.198.224]:38024 "EHLO rv-out-0506.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751666AbZA0F56 (ORCPT ); Tue, 27 Jan 2009 00:57:58 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type:content-transfer-encoding; b=JoYlM3VnEVSkGyl+kky7n0RaOvoI7Es87Iddd39voJMDN3wPNxoKICnd6qO2Av1pXx Uc/VRxva1Fwfi3olbzcrAgqTb6SAcSgTJ6+G0OWm4UklD1lGdc+uYcstlHyiPO0EbJCt 2joWofrFWUUoE3ZkdkMSRO10UI4i8xbSxXRys= MIME-Version: 1.0 In-Reply-To: <497E5F76.10301@goop.org> References: <497E5F76.10301@goop.org> Date: Tue, 27 Jan 2009 00:57:57 -0500 Message-ID: <73c1f2160901262157g3d281e62nb3ebafe01ab1dfe4@mail.gmail.com> Subject: Re: unified percpu stuff From: Brian Gerst To: Jeremy Fitzhardinge Cc: Tejun Heo , Ingo Molnar , Linux Kernel Mailing List Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1721 Lines: 48 On Mon, Jan 26, 2009 at 8:12 PM, Jeremy Fitzhardinge wrote: > I'm really pleased to see the unified percpu stuff in the kernel, but > unfortunately its breaking Xen at the moment. > It looks like this is just a matter of initializing %gs properly in > xen_start_kernel. Is there any problem with me doing a load_gs_base(0) > somewhere early in xen_start_kernel (arch/x86/xen/enlighten.c)? Some of the changes I did made the assumption that the percpu state is set up early in head_xx.S, which apparently is skipped for xen. Is there documentation anywhere for the xen bootstrap process? Try this patch (untested): diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c index bef941f..b90d061 100644 --- a/arch/x86/xen/enlighten.c +++ b/arch/x86/xen/enlighten.c @@ -1647,6 +1647,8 @@ asmlinkage void __init xen_start_kernel(void) have_vcpu_info_placement = 0; #endif + switch_to_new_gdt(); + xen_smp_init(); /* Get mfn list */ diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c index 7735e3d..00d9265 100644 --- a/arch/x86/xen/smp.c +++ b/arch/x86/xen/smp.c @@ -235,6 +235,8 @@ cpu_initialize_context(unsigned int cpu, struct task_struct *idle) ctxt->user_regs.ss = __KERNEL_DS; #ifdef CONFIG_X86_32 ctxt->user_regs.fs = __KERNEL_PERCPU; +#else + ctxt->gs_base_kernel = per_cpu_offset(cpu); #endif ctxt->user_regs.eip = (unsigned long)cpu_bringup_and_idle; ctxt->user_regs.eflags = 0x1000; /* IOPL_RING1 */ -- Brian Gerst -- 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/