From patchwork Thu Jun 15 22:41:21 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Tony Luck X-Patchwork-Id: 9790361 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 9A34A60384 for ; Thu, 15 Jun 2017 22:41:34 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 8B5BB2862E for ; Thu, 15 Jun 2017 22:41:34 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 8019F28631; Thu, 15 Jun 2017 22:41:34 +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 CBB042862E for ; Thu, 15 Jun 2017 22:41:33 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750899AbdFOWlc (ORCPT ); Thu, 15 Jun 2017 18:41:32 -0400 Received: from mga07.intel.com ([134.134.136.100]:28527 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750830AbdFOWlb (ORCPT ); Thu, 15 Jun 2017 18:41:31 -0400 Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by orsmga105.jf.intel.com with ESMTP; 15 Jun 2017 15:41:30 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.39,345,1493708400"; d="scan'208";a="115517757" Received: from agluck-desk.sc.intel.com ([10.3.52.160]) by fmsmga006.fm.intel.com with ESMTP; 15 Jun 2017 15:41:30 -0700 From: "Luck, Tony" To: "Rafael J . Wysocki" Cc: Tony Luck , Len Brown , Huang Ying , Borislav Petkov , Tomasz Nowicki , Jonathan Zhang , Tyler Baicar , linux-acpi@vger.kernel.org Subject: [PATCH v4] ACPI / APEI: Boot Error Record Table processing was needlessly complicated Date: Thu, 15 Jun 2017 15:41:21 -0700 Message-Id: <20170615224121.23949-1-tony.luck@intel.com> X-Mailer: git-send-email 2.11.0 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 Quoting version 6.1 of the ACPI specification. Section 18.3.1 "Boot Error Source" says: The Boot Error Region is a range of addressable memory OSPM can access during initialization to determine if an unhandled error condition occurred. System firmware must report this memory range as firmware reserved. The format of the Boot Error Region follow that of an Error Status Block, this is defined in Section 18.3.2.7. The format of the error status block is described by Table 18-342. This clarifies some points that were obfuscated in earlier versions. E.g. there is no longer a separate table to describe the format of the "Boot Error Region" (which was identical to the "Error Status Block"). Also saying "follow that of *an* Error Status Block" makes it clear that there is just one block (which can still contain multiple "Generic Error Data Entry structures"). The loop inside bert_print_all() is unnecessary (but probably harmless as the "while (remain > sizeof(struct acpi_bert_region))" loop should terminate after we skipped over the first entry. We can drop the "bert_print_all()" function and just move the four relevant lines inline in "bert_init()". Also this driver clears the "block_status" status field of the error status block in ACPI memory. I can see no justification for doing this in the ACPI spec. It is also highly kernel-ego-centric. There are user mode BERT harvesting tools that dig into /sys/firmware/acpi/tables/BERT which might like to see this summary value. Drop the: estatus->block_status = 0; Cc: Len Brown Cc: Huang Ying Cc: Borislav Petkov Cc: Tomasz Nowicki Cc: Jonathan (Zhixiong) Zhang Cc: Tyler Baicar Cc: linux-acpi@vger.kernel.org Signed-off-by: Tony Luck Reviewed-by: Borislav Petkov --- drivers/acpi/apei/bert.c | 59 ++++++++++-------------------------------------- 1 file changed, 12 insertions(+), 47 deletions(-) v4: don't clear block_status previous version was Reviewed-by: Borislav Petkov Tested-by: Tyler Baicar diff --git a/drivers/acpi/apei/bert.c b/drivers/acpi/apei/bert.c index 12771fcf0417..3b9b296dc84e 100644 --- a/drivers/acpi/apei/bert.c +++ b/drivers/acpi/apei/bert.c @@ -34,50 +34,6 @@ static int bert_disable; -static void __init bert_print_all(struct acpi_bert_region *region, - unsigned int region_len) -{ - struct acpi_hest_generic_status *estatus = - (struct acpi_hest_generic_status *)region; - int remain = region_len; - u32 estatus_len; - - if (!estatus->block_status) - return; - - while (remain > sizeof(struct acpi_bert_region)) { - if (cper_estatus_check(estatus)) { - pr_err(FW_BUG "Invalid error record.\n"); - return; - } - - estatus_len = cper_estatus_len(estatus); - if (remain < estatus_len) { - pr_err(FW_BUG "Truncated status block (length: %u).\n", - estatus_len); - return; - } - - pr_info_once("Error records from previous boot:\n"); - - cper_estatus_print(KERN_INFO HW_ERR, estatus); - - /* - * Because the boot error source is "one-time polled" type, - * clear Block Status of current Generic Error Status Block, - * once it's printed. - */ - estatus->block_status = 0; - - estatus = (void *)estatus + estatus_len; - /* No more error records. */ - if (!estatus->block_status) - return; - - remain -= estatus_len; - } -} - static int __init setup_bert_disable(char *str) { bert_disable = 1; @@ -89,7 +45,7 @@ __setup("bert_disable", setup_bert_disable); static int __init bert_check_table(struct acpi_table_bert *bert_tab) { if (bert_tab->header.length < sizeof(struct acpi_table_bert) || - bert_tab->region_length < sizeof(struct acpi_bert_region)) + bert_tab->region_length < sizeof(struct acpi_hest_generic_status)) return -EINVAL; return 0; @@ -98,7 +54,7 @@ static int __init bert_check_table(struct acpi_table_bert *bert_tab) static int __init bert_init(void) { struct apei_resources bert_resources; - struct acpi_bert_region *boot_error_region; + struct acpi_hest_generic_status *boot_error_region; struct acpi_table_bert *bert_tab; unsigned int region_len; acpi_status status; @@ -138,7 +94,16 @@ static int __init bert_init(void) goto out_fini; boot_error_region = ioremap_cache(bert_tab->address, region_len); if (boot_error_region) { - bert_print_all(boot_error_region, region_len); + if (boot_error_region->block_status) { + rc = cper_estatus_check(boot_error_region); + if (rc) { + pr_err(FW_BUG "Invalid error record.\n"); + iounmap(boot_error_region); + return rc; + } + pr_info("Error records from previous boot:\n"); + cper_estatus_print(KERN_INFO HW_ERR, boot_error_region); + } iounmap(boot_error_region); } else { rc = -ENOMEM;