From patchwork Thu Apr 7 10:51:20 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Lorenzo Pieralisi X-Patchwork-Id: 558886 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 56768C433F5 for ; Thu, 7 Apr 2022 10:51:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235597AbiDGKxd (ORCPT ); Thu, 7 Apr 2022 06:53:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44450 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230025AbiDGKxa (ORCPT ); Thu, 7 Apr 2022 06:53:30 -0400 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by lindbergh.monkeyblade.net (Postfix) with ESMTP id D34A3114DE9; Thu, 7 Apr 2022 03:51:29 -0700 (PDT) Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id 9FE5512FC; Thu, 7 Apr 2022 03:51:29 -0700 (PDT) Received: from e123427-lin.arm.com (unknown [10.57.6.208]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id C58153F5A1; Thu, 7 Apr 2022 03:51:27 -0700 (PDT) From: Lorenzo Pieralisi To: linux-kernel@vger.kernel.org Cc: Lorenzo Pieralisi , Ard Biesheuvel , Will Deacon , Hanjun Guo , Sudeep Holla , Catalin Marinas , "Rafael J. Wysocki" , linux-acpi@vger.kernel.org, linux-arm-kernel@lists.infradead.org, Veronika kabatova , Robin Murphy , Aristeu Rozanski Subject: [PATCH] ACPI: osl: Fix BERT error region memory mapping Date: Thu, 7 Apr 2022 11:51:20 +0100 Message-Id: <20220407105120.1280-1-lorenzo.pieralisi@arm.com> X-Mailer: git-send-email 2.31.0 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org Currently the sysfs interface maps the BERT error region as "memory" (through acpi_os_map_memory()) in order to copy the error records into memory buffers through memory operations (eg memory_read_from_buffer()). The OS system cannot detect whether the BERT error region is part of system RAM or it is "device memory" (eg BMC memory) and therefore it cannot detect which memory attributes the bus to memory support (and corresponding kernel mapping, unless firmware provides the required information). The acpi_os_map_memory() arch backend implementation determines the mapping attributes. On arm64, if the BERT error region is not present in the EFI memory map, the error region is mapped as device-nGnRnE; this triggers alignment faults since memcpy unaligned accesses are not allowed in device-nGnRnE regions. The ACPI sysfs code cannot therefore map by default the BERT error region with memory semantics but should use a safer default. Change the sysfs code to map the BERT error region as MMIO (through acpi_os_map_iomem()) and use the memcpy_fromio() interface to read the error region into the kernel buffer. Link: https://lore.kernel.org/linux-arm-kernel/31ffe8fc-f5ee-2858-26c5-0fd8bdd68702@arm.com Link: https://lore.kernel.org/linux-acpi/CAJZ5v0g+OVbhuUUDrLUCfX_mVqY_e8ubgLTU98=jfjTeb4t+Pw@mail.gmail.com Signed-off-by: Lorenzo Pieralisi Cc: Ard Biesheuvel Cc: Will Deacon Cc: Hanjun Guo Cc: Sudeep Holla Cc: Catalin Marinas Cc: "Rafael J. Wysocki" Tested-by: Veronika Kabatova Acked-by: Ard Biesheuvel --- drivers/acpi/sysfs.c | 25 ++++++++++++++++++------- 1 file changed, 18 insertions(+), 7 deletions(-) diff --git a/drivers/acpi/sysfs.c b/drivers/acpi/sysfs.c index a4b638bea6f1..cc2fe0618178 100644 --- a/drivers/acpi/sysfs.c +++ b/drivers/acpi/sysfs.c @@ -415,19 +415,30 @@ static ssize_t acpi_data_show(struct file *filp, struct kobject *kobj, loff_t offset, size_t count) { struct acpi_data_attr *data_attr; - void *base; - ssize_t rc; + void __iomem *base; + ssize_t size; data_attr = container_of(bin_attr, struct acpi_data_attr, attr); + size = data_attr->attr.size; + + if (offset < 0) + return -EINVAL; + + if (offset >= size) + return 0; - base = acpi_os_map_memory(data_attr->addr, data_attr->attr.size); + if (count > size - offset) + count = size - offset; + + base = acpi_os_map_iomem(data_attr->addr, size); if (!base) return -ENOMEM; - rc = memory_read_from_buffer(buf, count, &offset, base, - data_attr->attr.size); - acpi_os_unmap_memory(base, data_attr->attr.size); - return rc; + memcpy_fromio(buf, base + offset, count); + + acpi_os_unmap_iomem(base, size); + + return count; } static int acpi_bert_data_init(void *th, struct acpi_data_attr *data_attr)