1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * APEI Boot Error Record Table (BERT) support
4 *
5 * Copyright 2011 Intel Corp.
6 * Author: Huang Ying <ying.huang@intel.com>
7 *
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
16 * table.
17 *
18 * For more information about BERT, please refer to ACPI Specification
19 * version 4.0, section 17.3.1
20 */
21
22#include <linux/kernel.h>
23#include <linux/module.h>
24#include <linux/init.h>
25#include <linux/acpi.h>
26#include <linux/cper.h>
27#include <linux/io.h>
28
29#include "apei-internal.h"
30
31#undef pr_fmt
32#define pr_fmt(fmt) "BERT: " fmt
33
34#define ACPI_BERT_PRINT_MAX_RECORDS 5
35#define ACPI_BERT_PRINT_MAX_LEN 1024
36
37static int bert_disable __initdata;
38
39/*
40 * Print "all" the error records in the BERT table, but avoid huge spam to
41 * the console if the BIOS included oversize records, or too many records.
42 * Skipping some records here does not lose anything because the full
43 * data is available to user tools in:
44 * /sys/firmware/acpi/tables/data/BERT
45 */
46static void __init bert_print_all(struct acpi_bert_region *region,
47 unsigned int region_len)
48{
49 struct acpi_hest_generic_status *estatus =
50 (struct acpi_hest_generic_status *)region;
51 int remain = region_len;
52 int printed = 0, skipped = 0;
53 u32 estatus_len;
54
55 while (remain >= sizeof(struct acpi_bert_region)) {
56 estatus_len = cper_estatus_len(estatus);
57 if (remain < estatus_len) {
58 pr_err(FW_BUG "Truncated status block (length: %u).\n",
59 estatus_len);
60 break;
61 }
62
63 /* No more error records. */
64 if (!estatus->block_status)
65 break;
66
67 if (cper_estatus_check(estatus)) {
68 pr_err(FW_BUG "Invalid error record.\n");
69 break;
70 }
71
72 if (estatus_len < ACPI_BERT_PRINT_MAX_LEN &&
73 printed < ACPI_BERT_PRINT_MAX_RECORDS) {
74 pr_info_once("Error records from previous boot:\n");
75 cper_estatus_print(KERN_INFO HW_ERR, estatus);
76 printed++;
77 } else {
78 skipped++;
79 }
80
81 /*
82 * Because the boot error source is "one-time polled" type,
83 * clear Block Status of current Generic Error Status Block,
84 * once it's printed.
85 */
86 estatus->block_status = 0;
87
88 estatus = (void *)estatus + estatus_len;
89 remain -= estatus_len;
90 }
91
92 if (skipped)
93 pr_info(HW_ERR "Skipped %d error records\n", skipped);
94
95 if (printed + skipped)
96 pr_info("Total records found: %d\n", printed + skipped);
97}
98
99static int __init setup_bert_disable(char *str)
100{
101 bert_disable = 1;
102
103 return 1;
104}
105__setup("bert_disable", setup_bert_disable);
106
107static int __init bert_check_table(struct acpi_table_bert *bert_tab)
108{
109 if (bert_tab->header.length < sizeof(struct acpi_table_bert) ||
110 bert_tab->region_length < sizeof(struct acpi_bert_region))
111 return -EINVAL;
112
113 return 0;
114}
115
116static int __init bert_init(void)
117{
118 struct apei_resources bert_resources;
119 struct acpi_bert_region *boot_error_region;
120 struct acpi_table_bert *bert_tab;
121 unsigned int region_len;
122 acpi_status status;
123 int rc = 0;
124
125 if (acpi_disabled)
126 return 0;
127
128 if (bert_disable) {
129 pr_info("Boot Error Record Table support is disabled.\n");
130 return 0;
131 }
132
133 status = acpi_get_table(ACPI_SIG_BERT, instance: 0, out_table: (struct acpi_table_header **)&bert_tab);
134 if (status == AE_NOT_FOUND)
135 return 0;
136
137 if (ACPI_FAILURE(status)) {
138 pr_err("get table failed, %s.\n", acpi_format_exception(status));
139 return -EINVAL;
140 }
141
142 rc = bert_check_table(bert_tab);
143 if (rc) {
144 pr_err(FW_BUG "table invalid.\n");
145 goto out_put_bert_tab;
146 }
147
148 region_len = bert_tab->region_length;
149 apei_resources_init(resources: &bert_resources);
150 rc = apei_resources_add(resources: &bert_resources, start: bert_tab->address,
151 size: region_len, iomem: true);
152 if (rc)
153 goto out_put_bert_tab;
154 rc = apei_resources_request(resources: &bert_resources, desc: "APEI BERT");
155 if (rc)
156 goto out_fini;
157 boot_error_region = ioremap_cache(offset: bert_tab->address, size: region_len);
158 if (boot_error_region) {
159 bert_print_all(region: boot_error_region, region_len);
160 iounmap(addr: boot_error_region);
161 } else {
162 rc = -ENOMEM;
163 }
164
165 apei_resources_release(resources: &bert_resources);
166out_fini:
167 apei_resources_fini(resources: &bert_resources);
168out_put_bert_tab:
169 acpi_put_table(table: (struct acpi_table_header *)bert_tab);
170
171 return rc;
172}
173
174late_initcall(bert_init);
175

source code of linux/drivers/acpi/apei/bert.c