From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1753876AbcCWDOw (ORCPT <rfc822;w@1wt.eu>);
	Tue, 22 Mar 2016 23:14:52 -0400
Received: from szxga02-in.huawei.com ([119.145.14.65]:29289 "EHLO
	szxga02-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S1750921AbcCWDOo (ORCPT
	<rfc822;linux-kernel@vger.kernel.org>);
	Tue, 22 Mar 2016 23:14:44 -0400
To: <linux-pci@vger.kernel.org>, <catalin.marinas@arm.com>,
        linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
        <wangkefeng.wang@huawei.com>
CC: Gabriele Paoloni <gabriele.paoloni@huawei.com>,
        Arnd Bergmann <arnd@arndb.de>, <linux-kernel@vger.kernel.org>,
        <Lorenzo.Pieralisi@arm.com>, Linuxarm <linuxarm@huawei.com>,
        Zhou Wang <wangzhou1@hisilicon.com>
From: Kefeng Wang <wangkefeng.wang@huawei.com>
Subject: Question about PCI I/O space in ARM64
Message-ID: <56F209A9.4040304@huawei.com>
Date: Wed, 23 Mar 2016 11:12:41 +0800
User-Agent: Mozilla/5.0 (Windows NT 6.1; WOW64; rv:38.0) Gecko/20100101
 Thunderbird/38.5.1
MIME-Version: 1.0
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: 8bit
X-Originating-IP: [10.177.19.180]
X-CFilter-Loop: Reflected
X-Mirapoint-Virus-RAPID-Raw: score=unknown(0),
	refid=str=0001.0A020205.56F209E8.00AC,ss=1,re=0.000,recu=0.000,reip=0.000,cl=1,cld=1,fgs=0,
	ip=0.0.0.0,
	so=2013-06-18 04:22:30,
	dmn=2013-03-21 17:37:32
X-Mirapoint-Loop-Id: 5f079c3483574cff0d01dd6e82291500
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

Hi all，

If no pci, the PCI I/O space(16M) is mapped into an irrelevant mem space(right ?), not a right IO space,
that is, no one call pci_remap_iospace() to remap the memory mapped I/O space, once driver
like f71805f loaded, write value to IO space(see f71805f_init->f71805f_find->superio_enter->outb),
we met following oops,
------------------------
Unable to handle kernel paging request at virtual address ffffffbffee0002e
pgd = ffffffc1d68d4000
[ffffffbffee0002e] *pgd=0000000000000000, *pud=0000000000000000
Internal error: Oops: 94000046 [#1] PREEMPT SMP
Modules linked in: f71805f(+) hwmon
CPU: 3 PID: 1659 Comm: insmod Not tainted 4.5.0+ #88
Hardware name: linux,dummy-virt (DT)
task: ffffffc1f6665400 ti: ffffffc1d6418000 task.ti: ffffffc1d6418000
PC is at f71805f_find+0x6c/0x358 [f71805f]
------------------------

I am not clear about PCI I/O, but if this is indeed a bug, how to solve this issue,
any advice will be appreciated.

Thanks
Kefeng