From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 38585C10F0C for ; Thu, 4 Apr 2019 16:00:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 092012082E for ; Thu, 4 Apr 2019 16:00:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729110AbfDDQA2 (ORCPT ); Thu, 4 Apr 2019 12:00:28 -0400 Received: from szxga06-in.huawei.com ([45.249.212.32]:42716 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1728159AbfDDQA1 (ORCPT ); Thu, 4 Apr 2019 12:00:27 -0400 Received: from DGGEMS414-HUB.china.huawei.com (unknown [172.30.72.59]) by Forcepoint Email with ESMTP id D3E89F261A06665AAF7B; Fri, 5 Apr 2019 00:00:23 +0800 (CST) Received: from localhost.localdomain (10.67.212.75) by DGGEMS414-HUB.china.huawei.com (10.3.19.214) with Microsoft SMTP Server id 14.3.408.0; Fri, 5 Apr 2019 00:00:17 +0800 From: John Garry To: , , , CC: , , , , , , , , , , John Garry Subject: [PATCH v3 0/4] Fix system crash for accessing unmapped IO port regions Date: Thu, 4 Apr 2019 23:59:58 +0800 Message-ID: <1554393602-152448-1-git-send-email-john.garry@huawei.com> X-Mailer: git-send-email 2.8.1 MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.67.212.75] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org It was reported some time ago that arm64 systems will crash if a driver attempts to access IO port addresses when the PCI IO port region has not been mapped [1]. More recently, a similar crash is where the system PCI host probe fails, and the IPMI driver crashes the system while attempting to do some IO port accesses [2]. This patchset attempts to keep the kernel alive in such situations by 2 complementary methods: 1. Rejecting IO port resource requests until PCI IO port regions have been mapped (in a pci_remap_iospace() call). 2. Rejecting logic PIO access to PCI IO regions until, again, PCI IO port regions have been mapped About 1: Currently the PCI IO port region is initialized to the full range, {0, IO_SPACE_LIMIT}. As such, any IO port region requests would not fail because of PCI IO port regions not being mapped. Patch 1/4 looks to remedy this issue by ensuring IO port requests are made to direct children of ioport_resource (PCI host IO port regions), similar to Arnd's solution, mentioned in [1]: "I see that ioport_resource gets initialized to the {0, IO_SPACE_LIMIT} range. If we could change it so that pci_remap_iospace() hooks up to ioport_resource and extends it whenever something gets mapped there up to IO_SPACE_LIMIT, we can change the default range to {0,0}, which would fail for any request_region call before the first pci_remap_iospace." I didn't use this solution, as logical PIO space is sparse in {0, IO_SPACE_LIMIT}, so we cannot simply grow the region. *As discussed with Bjorn in v2 series, we doubt that this approach is sound, as legacy ISA devices do not necessarily reply on PCI.* However I will keep the patch in the series as a reference and as a topic of debate. It's also an RFC as the implementation solution is not idea. About 2: Some drivers - like f71805f hwmon driver - do not call request_{muxed_}region() prior to accessing IO port regions, as they should do. So patches 2-3/4 adds a safeguard against this, in that unwarranted PIO IO accesses will be discarded in the low-level accessors. About the issue of f71805f driver not requesting the IO port region - many drivers do this, and need to be fixed up separately. 1. https://lore.kernel.org/linux-pci/56F209A9.4040304@huawei.com 2. https://lore.kernel.org/linux-arm-kernel/e6995b4a-184a-d8d4-f4d4-9ce75d8f47c0@huawei.com/ Differences to v2 patchset: https://lkml.org/lkml/2019/3/20/788 - Add a patch to use logical PIO accessors for !CONFIG_INDIRECT_PIO - Some tidy-up according to Andy's review Differences to v1 patchset: https://lkml.org/lkml/2019/3/14/630 - Drop f71805f fix - it can be done in a separate patchset - Change implementation in resource.c patch to check if parent of region is ioport_resource - Add patch to fix some logic_pio.c prints John Garry (4): resource: Request IO port regions from children of ioport_resource lib: logic_pio: Use logical PIO low-level accessors for !CONFIG_INDIRECT_PIO lib: logic_pio: Reject accesses to unregistered CPU MMIO regions lib: logic_pio: Fix up some prints include/linux/ioport.h | 11 ++- include/linux/logic_pio.h | 7 +- kernel/resource.c | 28 +++++++ lib/logic_pio.c | 157 +++++++++++++++++++++++++++++--------- 4 files changed, 159 insertions(+), 44 deletions(-) -- 2.17.1