1 // SPDX-License-Identifier: GPL-2.0-only
3 * APEI Boot Error Record Table (BERT) support
5 * Copyright 2011 Intel Corp.
6 * Author: Huang Ying <ying.huang@intel.com>
8 * Under normal circumstances, when a hardware error occurs, the error
9 * handler receives control and processes the error. This gives OSPM a
10 * chance to process the error condition, report it, and optionally attempt
11 * recovery. In some cases, the system is unable to process an error.
12 * For example, system firmware or a management controller may choose to
13 * reset the system or the system might experience an uncontrolled crash
14 * or reset.The boot error source is used to report unhandled errors that
15 * occurred in a previous boot. This mechanism is described in the BERT
18 * For more information about BERT, please refer to ACPI Specification
19 * version 4.0, section 17.3.1
22 #include <linux/kernel.h>
23 #include <linux/module.h>
24 #include <linux/init.h>
25 #include <linux/acpi.h>
28 #include "apei-internal.h"
31 #define pr_fmt(fmt) "BERT: " fmt
32 #define ACPI_BERT_PRINT_MAX_LEN 1024
34 static int bert_disable;
36 static void __init bert_print_all(struct acpi_bert_region *region,
37 unsigned int region_len)
39 struct acpi_hest_generic_status *estatus =
40 (struct acpi_hest_generic_status *)region;
41 int remain = region_len;
44 while (remain >= sizeof(struct acpi_bert_region)) {
45 estatus_len = cper_estatus_len(estatus);
46 if (remain < estatus_len) {
47 pr_err(FW_BUG "Truncated status block (length: %u).\n",
52 /* No more error records. */
53 if (!estatus->block_status)
56 if (cper_estatus_check(estatus)) {
57 pr_err(FW_BUG "Invalid error record.\n");
61 pr_info_once("Error records from previous boot:\n");
62 if (region_len < ACPI_BERT_PRINT_MAX_LEN)
63 cper_estatus_print(KERN_INFO HW_ERR, estatus);
65 pr_info_once("Max print length exceeded, table data is available at:\n"
66 "/sys/firmware/acpi/tables/data/BERT");
69 * Because the boot error source is "one-time polled" type,
70 * clear Block Status of current Generic Error Status Block,
73 estatus->block_status = 0;
75 estatus = (void *)estatus + estatus_len;
76 remain -= estatus_len;
80 static int __init setup_bert_disable(char *str)
86 __setup("bert_disable", setup_bert_disable);
88 static int __init bert_check_table(struct acpi_table_bert *bert_tab)
90 if (bert_tab->header.length < sizeof(struct acpi_table_bert) ||
91 bert_tab->region_length < sizeof(struct acpi_bert_region))
97 static int __init bert_init(void)
99 struct apei_resources bert_resources;
100 struct acpi_bert_region *boot_error_region;
101 struct acpi_table_bert *bert_tab;
102 unsigned int region_len;
110 pr_info("Boot Error Record Table support is disabled.\n");
114 status = acpi_get_table(ACPI_SIG_BERT, 0, (struct acpi_table_header **)&bert_tab);
115 if (status == AE_NOT_FOUND)
118 if (ACPI_FAILURE(status)) {
119 pr_err("get table failed, %s.\n", acpi_format_exception(status));
123 rc = bert_check_table(bert_tab);
125 pr_err(FW_BUG "table invalid.\n");
126 goto out_put_bert_tab;
129 region_len = bert_tab->region_length;
130 apei_resources_init(&bert_resources);
131 rc = apei_resources_add(&bert_resources, bert_tab->address,
134 goto out_put_bert_tab;
135 rc = apei_resources_request(&bert_resources, "APEI BERT");
138 boot_error_region = ioremap_cache(bert_tab->address, region_len);
139 if (boot_error_region) {
140 bert_print_all(boot_error_region, region_len);
141 iounmap(boot_error_region);
146 apei_resources_release(&bert_resources);
148 apei_resources_fini(&bert_resources);
150 acpi_put_table((struct acpi_table_header *)bert_tab);
155 late_initcall(bert_init);