From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934614AbYBNBAB (ORCPT ); Wed, 13 Feb 2008 20:00:01 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S934254AbYBNA7i (ORCPT ); Wed, 13 Feb 2008 19:59:38 -0500 Received: from nf-out-0910.google.com ([64.233.182.191]:41331 "EHLO nf-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933651AbYBNA7f (ORCPT ); Wed, 13 Feb 2008 19:59:35 -0500 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=message-id:date:from:sender:to:subject:cc:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references:x-google-sender-auth; b=qHhjoka6pwkxolaA5MOskDTEgNGzqV885s81QfZeUOIkLRzlzrm3D4Jxw7g6CDMwzB81+Yqmq6dcUGpFUYIcYzZj7Fyjf7SMOu6SrgtT+quHt5ORwJqUe58T50f/6CZaUu28zsrSIdpb/rGkAgpdNBISOJAO+g6j8+iqcB7x91I= Message-ID: <12c511ca0802131659u6e4407d9w96148fe72d6e11d7@mail.gmail.com> Date: Wed, 13 Feb 2008 16:59:30 -0800 From: "Tony Luck" To: "David Miller" Subject: Re: Strange hang on ia64 with CONFIG_PRINTK_TIME=y Cc: mingo@elte.hu, rdreier@cisco.com, linux-kernel@vger.kernel.org In-Reply-To: <20080213.050340.64342037.davem@davemloft.net> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <20080212.230156.33759433.davem@davemloft.net> <20080213125725.GC6344@elte.hu> <20080213.050340.64342037.davem@davemloft.net> X-Google-Sender-Auth: 0b059e25c93b92a0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org > It is legal to access per-cpu data as early as you like, > it just evaluates to the static copy in the per-cpu section > of the kernel image until the per-cpu areas are setup. On ia64 per-cpu variables are mapped into the top 64K of the address space. Accessing them before the resources to handle the access to that virtual address have been set up would cause problems. -Tony