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
 33static int bert_disable;
 34
 35static void __init bert_print_all(struct acpi_bert_region *region,
 36				  unsigned int region_len)
 37{
 38	struct acpi_hest_generic_status *estatus =
 39		(struct acpi_hest_generic_status *)region;
 40	int remain = region_len;
 41	u32 estatus_len;
 42
 43	while (remain >= sizeof(struct acpi_bert_region)) {
 44		estatus_len = cper_estatus_len(estatus);
 45		if (remain < estatus_len) {
 46			pr_err(FW_BUG "Truncated status block (length: %u).\n",
 47			       estatus_len);
 48			return;
 49		}
 50
 51		/* No more error records. */
 52		if (!estatus->block_status)
 53			return;
 54
 55		if (cper_estatus_check(estatus)) {
 56			pr_err(FW_BUG "Invalid error record.\n");
 57			return;
 58		}
 59
 60		pr_info_once("Error records from previous boot:\n");
 61
 62		cper_estatus_print(KERN_INFO HW_ERR, estatus);
 63
 64		/*
 65		 * Because the boot error source is "one-time polled" type,
 66		 * clear Block Status of current Generic Error Status Block,
 67		 * once it's printed.
 68		 */
 69		estatus->block_status = 0;
 70
 71		estatus = (void *)estatus + estatus_len;
 72		remain -= estatus_len;
 73	}
 74}
 75
 76static int __init setup_bert_disable(char *str)
 77{
 78	bert_disable = 1;
 79
 80	return 0;
 81}
 82__setup("bert_disable", setup_bert_disable);
 83
 84static int __init bert_check_table(struct acpi_table_bert *bert_tab)
 85{
 86	if (bert_tab->header.length < sizeof(struct acpi_table_bert) ||
 87	    bert_tab->region_length < sizeof(struct acpi_bert_region))
 88		return -EINVAL;
 89
 90	return 0;
 91}
 92
 93static int __init bert_init(void)
 94{
 95	struct apei_resources bert_resources;
 96	struct acpi_bert_region *boot_error_region;
 97	struct acpi_table_bert *bert_tab;
 98	unsigned int region_len;
 99	acpi_status status;
100	int rc = 0;
101
102	if (acpi_disabled)
103		return 0;
104
105	if (bert_disable) {
106		pr_info("Boot Error Record Table support is disabled.\n");
107		return 0;
108	}
109
110	status = acpi_get_table(ACPI_SIG_BERT, 0, (struct acpi_table_header **)&bert_tab);
111	if (status == AE_NOT_FOUND)
112		return 0;
113
114	if (ACPI_FAILURE(status)) {
115		pr_err("get table failed, %s.\n", acpi_format_exception(status));
116		return -EINVAL;
117	}
118
119	rc = bert_check_table(bert_tab);
120	if (rc) {
121		pr_err(FW_BUG "table invalid.\n");
122		goto out_put_bert_tab;
123	}
124
125	region_len = bert_tab->region_length;
126	apei_resources_init(&bert_resources);
127	rc = apei_resources_add(&bert_resources, bert_tab->address,
128				region_len, true);
129	if (rc)
130		goto out_put_bert_tab;
131	rc = apei_resources_request(&bert_resources, "APEI BERT");
132	if (rc)
133		goto out_fini;
134	boot_error_region = ioremap_cache(bert_tab->address, region_len);
135	if (boot_error_region) {
136		bert_print_all(boot_error_region, region_len);
137		iounmap(boot_error_region);
138	} else {
139		rc = -ENOMEM;
140	}
141
142	apei_resources_release(&bert_resources);
143out_fini:
144	apei_resources_fini(&bert_resources);
145out_put_bert_tab:
146	acpi_put_table((struct acpi_table_header *)bert_tab);
147
148	return rc;
149}
150
151late_initcall(bert_init);