From patchwork Thu Aug 17 21:39:46 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tony Luck X-Patchwork-Id: 9907161 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 401C760386 for ; Thu, 17 Aug 2017 21:39:51 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 31F5728BDC for ; Thu, 17 Aug 2017 21:39:51 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 2684B28BDE; Thu, 17 Aug 2017 21:39:51 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 6461428BDC for ; Thu, 17 Aug 2017 21:39:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753299AbdHQVjt (ORCPT ); Thu, 17 Aug 2017 17:39:49 -0400 Received: from mga11.intel.com ([192.55.52.93]:6094 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753297AbdHQVjs (ORCPT ); Thu, 17 Aug 2017 17:39:48 -0400 Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by fmsmga102.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 17 Aug 2017 14:39:48 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.41,389,1498546800"; d="scan'208";a="891202026" Received: from agluck-desk.sc.intel.com ([10.3.52.160]) by FMSMGA003.fm.intel.com with ESMTP; 17 Aug 2017 14:39:48 -0700 From: "Luck, Tony" To: "Rafael J. Wysocki" Cc: Tony Luck , Len Brown , Boris Petkov , Tyler Baicar , Punit Agrawal , linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH] ACPI / sysfs: Extend ACPI sysfs to provide access to boot error region Date: Thu, 17 Aug 2017 14:39:46 -0700 Message-Id: <20170817213946.16939-1-tony.luck@intel.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: References: Sender: linux-acpi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-acpi@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Tony Luck The ACPI sysfs interface provides a way to read each ACPI table from userspace via entries in /sys/firmware/acpi/tables/ The BERT table simply provides the size and address of the error record in BIOS reserved memory and users may want access to this record. In an earlier age we might have used /dev/mem to retrieve this error record, but many systems disable /dev/mem for security reasons. Extend this driver to provide read-only access to the data via a file in a new directory /sys/firmware/acpi/tables/data/BERT Cc: Len Brown Cc: Boris Petkov Cc: Tyler Baicar Cc: Punit Agrawal Cc: linux-acpi@vger.kernel.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Tony Luck v4: (suggested by Punit Agrawal) extend the /sys/firmware/acpi code to provide this functionality. File/directory names changed to Rafael's suggestions Acked-by: Punit Agrawal --- drivers/acpi/sysfs.c | 79 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 79 insertions(+) diff --git a/drivers/acpi/sysfs.c b/drivers/acpi/sysfs.c index e414fabf7315..7c4eed0594d0 100644 --- a/drivers/acpi/sysfs.c +++ b/drivers/acpi/sysfs.c @@ -306,11 +306,13 @@ module_param_call(acpica_version, NULL, param_get_acpica_version, NULL, 0444); /* * ACPI table sysfs I/F: * /sys/firmware/acpi/tables/ + * /sys/firmware/acpi/tables-data/ * /sys/firmware/acpi/tables/dynamic/ */ static LIST_HEAD(acpi_table_attr_list); static struct kobject *tables_kobj; +static struct kobject *tables_data_kobj; static struct kobject *dynamic_tables_kobj; static struct kobject *hotplug_kobj; @@ -325,6 +327,11 @@ struct acpi_table_attr { struct list_head node; }; +struct acpi_data_attr { + struct bin_attribute attr; + u64 addr; +}; + static ssize_t acpi_table_show(struct file *filp, struct kobject *kobj, struct bin_attribute *bin_attr, char *buf, loff_t offset, size_t count) @@ -420,6 +427,70 @@ acpi_status acpi_sysfs_table_handler(u32 event, void *table, void *context) return AE_OK; } +static ssize_t acpi_data_show(struct file *filp, struct kobject *kobj, + struct bin_attribute *bin_attr, char *buf, + loff_t offset, size_t count) +{ + struct acpi_data_attr *data_attr; + void __iomem *base; + ssize_t rc; + + data_attr = container_of(bin_attr, struct acpi_data_attr, attr); + + base = acpi_os_map_memory(data_attr->addr, data_attr->attr.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; +} + +static int acpi_bert_data_init(void *th, struct acpi_data_attr *data_attr) +{ + struct acpi_table_bert *bert = th; + + if (bert->header.length < sizeof(struct acpi_table_bert) || + bert->region_length < sizeof(struct acpi_hest_generic_status)) { + kfree(data_attr); + return -EINVAL; + } + data_attr->addr = bert->address; + data_attr->attr.size = bert->region_length; + data_attr->attr.attr.name = "BERT"; + + return sysfs_create_bin_file(tables_data_kobj, &data_attr->attr); +} + +static struct acpi_data_obj { + char *name; + int (*fn)(void *, struct acpi_data_attr *); +} acpi_data_objs[] = { + { ACPI_SIG_BERT, acpi_bert_data_init }, +}; + +#define NUM_ACPI_DATA_OBJS ARRAY_SIZE(acpi_data_objs) + +static int acpi_table_data_init(struct acpi_table_header *th) +{ + struct acpi_data_attr *data_attr; + int i; + + for (i = 0; i < NUM_ACPI_DATA_OBJS; i++) { + if (ACPI_COMPARE_NAME(th->signature, acpi_data_objs[i].name)) { + data_attr = kzalloc(sizeof(*data_attr), GFP_KERNEL); + if (!data_attr) + return -ENOMEM; + sysfs_attr_init(&data_attr->attr.attr); + data_attr->attr.read = acpi_data_show; + data_attr->attr.attr.mode = 0400; + return acpi_data_objs[i].fn(th, data_attr); + } + } + return 0; +} + static int acpi_tables_sysfs_init(void) { struct acpi_table_attr *table_attr; @@ -432,6 +503,10 @@ static int acpi_tables_sysfs_init(void) if (!tables_kobj) goto err; + tables_data_kobj = kobject_create_and_add("data", tables_kobj); + if (!tables_data_kobj) + goto err_tables_data; + dynamic_tables_kobj = kobject_create_and_add("dynamic", tables_kobj); if (!dynamic_tables_kobj) goto err_dynamic_tables; @@ -456,13 +531,17 @@ static int acpi_tables_sysfs_init(void) return ret; } list_add_tail(&table_attr->node, &acpi_table_attr_list); + acpi_table_data_init(table_header); } kobject_uevent(tables_kobj, KOBJ_ADD); + kobject_uevent(tables_data_kobj, KOBJ_ADD); kobject_uevent(dynamic_tables_kobj, KOBJ_ADD); return 0; err_dynamic_tables: + kobject_put(tables_data_kobj); +err_tables_data: kobject_put(tables_kobj); err: return -ENOMEM;