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, 0, (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(&bert_resources);
150	rc = apei_resources_add(&bert_resources, bert_tab->address,
151				region_len, true);
152	if (rc)
153		goto out_put_bert_tab;
154	rc = apei_resources_request(&bert_resources, "APEI BERT");
155	if (rc)
156		goto out_fini;
157	boot_error_region = ioremap_cache(bert_tab->address, region_len);
158	if (boot_error_region) {
159		bert_print_all(boot_error_region, region_len);
160		iounmap(boot_error_region);
161	} else {
162		rc = -ENOMEM;
163	}
164
165	apei_resources_release(&bert_resources);
166out_fini:
167	apei_resources_fini(&bert_resources);
168out_put_bert_tab:
169	acpi_put_table((struct acpi_table_header *)bert_tab);
170
171	return rc;
172}
173
174late_initcall(bert_init);