xref: /kernel/linux/linux-5.10/drivers/acpi/apei/bert.c (revision 8c2ecf20) 
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/io.h>
27
28#include "apei-internal.h"
29
30#undef pr_fmt
31#define pr_fmt(fmt) "BERT: " fmt
32
33#define ACPI_BERT_PRINT_MAX_RECORDS 5
34#define ACPI_BERT_PRINT_MAX_LEN 1024
35
36static int bert_disable;
37
38/*
39 * Print "all" the error records in the BERT table, but avoid huge spam to
40 * the console if the BIOS included oversize records, or too many records.
41 * Skipping some records here does not lose anything because the full
42 * data is available to user tools in:
43 *	/sys/firmware/acpi/tables/data/BERT
44 */
45static void __init bert_print_all(struct acpi_bert_region *region,
46				  unsigned int region_len)
47{
48	struct acpi_hest_generic_status *estatus =
49		(struct acpi_hest_generic_status *)region;
50	int remain = region_len;
51	int printed = 0, skipped = 0;
52	u32 estatus_len;
53
54	while (remain >= sizeof(struct acpi_bert_region)) {
55		estatus_len = cper_estatus_len(estatus);
56		if (remain < estatus_len) {
57			pr_err(FW_BUG "Truncated status block (length: %u).\n",
58			       estatus_len);
59			break;
60		}
61
62		/* No more error records. */
63		if (!estatus->block_status)
64			break;
65
66		if (cper_estatus_check(estatus)) {
67			pr_err(FW_BUG "Invalid error record.\n");
68			break;
69		}
70
71		if (estatus_len < ACPI_BERT_PRINT_MAX_LEN &&
72		    printed < ACPI_BERT_PRINT_MAX_RECORDS) {
73			pr_info_once("Error records from previous boot:\n");
74			cper_estatus_print(KERN_INFO HW_ERR, estatus);
75			printed++;
76		} else {
77			skipped++;
78		}
79
80		/*
81		 * Because the boot error source is "one-time polled" type,
82		 * clear Block Status of current Generic Error Status Block,
83		 * once it's printed.
84		 */
85		estatus->block_status = 0;
86
87		estatus = (void *)estatus + estatus_len;
88		remain -= estatus_len;
89	}
90
91	if (skipped)
92		pr_info(HW_ERR "Skipped %d error records\n", skipped);
93}
94
95static int __init setup_bert_disable(char *str)
96{
97	bert_disable = 1;
98
99	return 1;
100}
101__setup("bert_disable", setup_bert_disable);
102
103static int __init bert_check_table(struct acpi_table_bert *bert_tab)
104{
105	if (bert_tab->header.length < sizeof(struct acpi_table_bert) ||
106	    bert_tab->region_length < sizeof(struct acpi_bert_region))
107		return -EINVAL;
108
109	return 0;
110}
111
112static int __init bert_init(void)
113{
114	struct apei_resources bert_resources;
115	struct acpi_bert_region *boot_error_region;
116	struct acpi_table_bert *bert_tab;
117	unsigned int region_len;
118	acpi_status status;
119	int rc = 0;
120
121	if (acpi_disabled)
122		return 0;
123
124	if (bert_disable) {
125		pr_info("Boot Error Record Table support is disabled.\n");
126		return 0;
127	}
128
129	status = acpi_get_table(ACPI_SIG_BERT, 0, (struct acpi_table_header **)&bert_tab);
130	if (status == AE_NOT_FOUND)
131		return 0;
132
133	if (ACPI_FAILURE(status)) {
134		pr_err("get table failed, %s.\n", acpi_format_exception(status));
135		return -EINVAL;
136	}
137
138	rc = bert_check_table(bert_tab);
139	if (rc) {
140		pr_err(FW_BUG "table invalid.\n");
141		goto out_put_bert_tab;
142	}
143
144	region_len = bert_tab->region_length;
145	apei_resources_init(&bert_resources);
146	rc = apei_resources_add(&bert_resources, bert_tab->address,
147				region_len, true);
148	if (rc)
149		goto out_put_bert_tab;
150	rc = apei_resources_request(&bert_resources, "APEI BERT");
151	if (rc)
152		goto out_fini;
153	boot_error_region = ioremap_cache(bert_tab->address, region_len);
154	if (boot_error_region) {
155		bert_print_all(boot_error_region, region_len);
156		iounmap(boot_error_region);
157	} else {
158		rc = -ENOMEM;
159	}
160
161	apei_resources_release(&bert_resources);
162out_fini:
163	apei_resources_fini(&bert_resources);
164out_put_bert_tab:
165	acpi_put_table((struct acpi_table_header *)bert_tab);
166
167	return rc;
168}
169
170late_initcall(bert_init);
171