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=-7.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 E5594C4360F for ; Thu, 14 Mar 2019 17:39:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C042E2184C for ; Thu, 14 Mar 2019 17:39:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727012AbfCNRjc (ORCPT ); Thu, 14 Mar 2019 13:39:32 -0400 Received: from szxga06-in.huawei.com ([45.249.212.32]:51138 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726485AbfCNRjc (ORCPT ); Thu, 14 Mar 2019 13:39:32 -0400 Received: from DGGEMS407-HUB.china.huawei.com (unknown [172.30.72.60]) by Forcepoint Email with ESMTP id 4EC82A647B1B31D17CEB; Fri, 15 Mar 2019 01:39:29 +0800 (CST) Received: from [127.0.0.1] (10.202.227.238) by DGGEMS407-HUB.china.huawei.com (10.3.19.207) with Microsoft SMTP Server id 14.3.408.0; Fri, 15 Mar 2019 01:39:19 +0800 Subject: Re: [RFC PATCH 1/2] resource: Request IO port regions from children of ioport_resource To: Guenter Roeck References: <1552582516-70855-1-git-send-email-john.garry@huawei.com> <1552582516-70855-2-git-send-email-john.garry@huawei.com> <20190314171200.GC14159@roeck-us.net> CC: , , , , , , , , , , From: John Garry Message-ID: <57946772-f0e0-4099-3fa1-e59b216bad22@huawei.com> Date: Thu, 14 Mar 2019 17:39:12 +0000 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:45.0) Gecko/20100101 Thunderbird/45.3.0 MIME-Version: 1.0 In-Reply-To: <20190314171200.GC14159@roeck-us.net> Content-Type: text/plain; charset="windows-1252"; format=flowed Content-Transfer-Encoding: 7bit X-Originating-IP: [10.202.227.238] X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 14/03/2019 17:12, Guenter Roeck wrote: > On Fri, Mar 15, 2019 at 12:55:15AM +0800, John Garry wrote: >> Currently when we request an IO port region, the request is made directly >> to the top resource, ioport_resource. >> >> There is an issue here, in that drivers may request an IO port region even >> if the IO port region has not even been mapped in (in pci_remap_iospace()). >> >> This may lead to crashes when the PCI host has not enumerated prior to >> accessing the IO port region, as below: >> >> root@(none)$ insmod f71805f.ko >> [ 32.264016] Unable to handle kernel paging request at virtual address ffff7dfffee0002e >> [ 32.279936] Mem abort info: >> [ 32.285536] ESR = 0x96000046 >> [ 32.291657] Exception class = DABT (current EL), IL = 32 bits >> [ 32.303542] SET = 0, FnV = 0 >> [ 32.309661] EA = 0, S1PTW = 0 >> [ 32.315957] Data abort info: >> [ 32.321728] ISV = 0, ISS = 0x00000046 >> [ 32.329420] CM = 0, WnR = 1 >> [ 32.335367] swapper pgtable: 4k pages, 48-bit VAs, pgdp = (____ptrval____) >> [ 32.349174] [ffff7dfffee0002e] pgd=0000000001392003, pud=0000000001393003, pmd=0000000000000000 >> [ 32.366652] Internal error: Oops: 96000046 [#1] PREEMPT SMP >> [ 32.377835] Modules linked in: f71805f(+) >> [ 32.385876] CPU: 4 PID: 2681 Comm: insmod Not tainted 5.0.0-00003-ga6247cc0f8f2 #52 >> [ 32.401252] Hardware name: Huawei Taishan 2280 /D05, BIOS Hisilicon D05 IT21 Nemo 2.0 RC0 04/18/2018 >> [ 32.419597] pstate: 80000005 (Nzcv daif -PAN -UAO) >> [ 32.429213] pc : logic_outb+0x54/0xb8 >> [ 32.436556] lr : f71805f_find+0x2c/0x1b8 [f71805f] >> [ 32.446167] sp : ffff0000256bba90 >> [ 32.452808] x29: ffff0000256bba90 x28: ffff000008b544d0 >> [ 32.463468] x27: ffff0000256bbdf0 x26: 0000000000000100 >> [ 32.474127] x25: 000000000000002c x24: ffff000011396000 >> [ 32.484787] x23: ffff0000256bbb3e x22: ffff0000256bbb40 >> [ 32.495446] x21: ffff000008b591b8 x20: 0000000000000087 >> [ 32.506106] x19: 000000000000002e x18: ffffffffffffffff >> [ 32.516765] x17: 0000000000000000 x16: 0000000000000000 >> [ 32.527424] x15: 0000000000000400 x14: 0000000000000400 >> [ 32.538084] x13: 0000000000001832 x12: 0000000000000000 >> [ 32.548743] x11: ffff801ffbf08ac0 x10: 0000801fead02000 >> [ 32.559403] x9 : ffff801ffbffe840 x8 : 0000000000000001 >> [ 32.570062] x7 : 0000000000210d00 x6 : 0000000000000000 >> [ 32.580721] x5 : ffff801fb3eac380 x4 : ffff801ffbef4b20 >> [ 32.591381] x3 : 0000000000ffbffe x2 : ffff0000256bbb40 >> [ 32.602040] x1 : ffff7dfffee0002e x0 : ffff7dfffee00000 >> [ 32.612701] Process insmod (pid: 2681, stack limit = 0x(____ptrval____)) >> [ 32.626155] Call trace: >> [ 32.631050] logic_outb+0x54/0xb8 >> [ 32.637693] f71805f_find+0x2c/0x1b8 [f71805f] >> [ 32.646607] f71805f_init+0x38/0xe48 [f71805f] >> [ 32.655521] do_one_initcall+0x5c/0x178 >> [ 32.663212] do_init_module+0x58/0x1b0 >> [ 32.670728] load_module+0x1dc8/0x2178 >> [ 32.678243] __se_sys_init_module+0x14c/0x1e8 >> [ 32.686981] __arm64_sys_init_module+0x18/0x20 >> [ 32.695894] el0_svc_common+0x60/0x100 >> [ 32.703409] el0_svc_handler+0x2c/0x80 >> [ 32.710924] el0_svc+0x8/0xc >> [ 32.716693] Code: d2bfdc00 f2cfbfe0 f2ffffe0 8b000021 (39000034) >> [ 32.728925] ---[ end trace ddb5e493ee686685 ]--- >> Segmentation fault >> root@(none)$ >> >> This issue was originally reported in [1]. >> >> This patch changes the functionality of request_region() to request a >> region of the direct children of the top ioport_resource. >> >> In this, if the IO port region has not been mapped for a particular IO >> region, a suitable child region will not exist, and, as such, >> request_region() calls will fail. >> >> A side note: there are many drivers in the kernel which fail to even call >> request_region() prior to IO port accesses, and they also need to be fixed >> (to call request_region() as appropriate). >> Hi Guenter, > > Isn't that orthogonal to this problem ? Yes, it is really. I only added the f71805f driver fixup to illustrate the problem in resource.c and the potential system crash, and how this patch would fix it. > >> [1] https://www.spinics.net/lists/linux-pci/msg49821.html >> >> Signed-off-by: John Garry >> --- >> include/linux/ioport.h | 6 +++++- >> kernel/resource.c | 19 +++++++++++++++++++ >> 2 files changed, 24 insertions(+), 1 deletion(-) >> >> diff --git a/include/linux/ioport.h b/include/linux/ioport.h >> index da0ebaec25f0..cf40e1ed8211 100644 >> --- a/include/linux/ioport.h >> +++ b/include/linux/ioport.h >> @@ -217,7 +217,7 @@ static inline bool resource_contains(struct resource *r1, struct resource *r2) >> >> >> /* Convenience shorthand with allocation */ >> -#define request_region(start,n,name) __request_region(&ioport_resource, (start), (n), (name), 0) >> +#define request_region(start,n,name) __request_region_from_children(&ioport_resource, (start), (n), (name), 0) >> #define request_muxed_region(start,n,name) __request_region(&ioport_resource, (start), (n), (name), IORESOURCE_MUXED) >> #define __request_mem_region(start,n,name, excl) __request_region(&iomem_resource, (start), (n), (name), excl) >> #define request_mem_region(start,n,name) __request_region(&iomem_resource, (start), (n), (name), 0) > > I can't comment on the merits of the patch (though I am a bit concerned > about its impact and potential source of regressions),but I don't really > understand why it would only apply to request_region() and not to > request_muxed_region(). Is this an oversight or on purpose ? It's an oversight, which would be fixed. Thanks, John > > Guenter > > . >