1/*
  2 * APEI Boot Error Record Table (BERT) support
  3 *
  4 * Copyright 2011 Intel Corp.
  5 *   Author: Huang Ying <ying.huang@intel.com>
  6 *
  7 * Under normal circumstances, when a hardware error occurs, the error
  8 * handler receives control and processes the error. This gives OSPM a
  9 * chance to process the error condition, report it, and optionally attempt
 10 * recovery. In some cases, the system is unable to process an error.
 11 * For example, system firmware or a management controller may choose to
 12 * reset the system or the system might experience an uncontrolled crash
 13 * or reset.The boot error source is used to report unhandled errors that
 14 * occurred in a previous boot. This mechanism is described in the BERT
 15 * table.
 16 *
 17 * For more information about BERT, please refer to ACPI Specification
 18 * version 4.0, section 17.3.1
 19 *
 20 * This file is licensed under GPLv2.
 21 *
 22 */
 23
 24#include <linux/kernel.h>
 25#include <linux/module.h>
 26#include <linux/init.h>
 27#include <linux/acpi.h>
 28#include <linux/io.h>
 29
 30#include "apei-internal.h"
 31
 32#undef pr_fmt
 33#define pr_fmt(fmt) "BERT: " fmt
 34
 35static int bert_disable;
 36
 37static void __init bert_print_all(struct acpi_bert_region *region,
 38				  unsigned int region_len)
 39{
 40	struct acpi_hest_generic_status *estatus =
 41		(struct acpi_hest_generic_status *)region;
 42	int remain = region_len;
 43	u32 estatus_len;
 44
 45	if (!estatus->block_status)
 46		return;
 47
 48	while (remain > sizeof(struct acpi_bert_region)) {
 49		if (cper_estatus_check(estatus)) {
 50			pr_err(FW_BUG "Invalid error record.\n");
 51			return;
 52		}
 53
 54		estatus_len = cper_estatus_len(estatus);
 55		if (remain < estatus_len) {
 56			pr_err(FW_BUG "Truncated status block (length: %u).\n",
 57			       estatus_len);
 58			return;
 59		}
 60
 61		pr_info_once("Error records from previous boot:\n");
 62
 63		cper_estatus_print(KERN_INFO HW_ERR, estatus);
 64
 65		/*
 66		 * Because the boot error source is "one-time polled" type,
 67		 * clear Block Status of current Generic Error Status Block,
 68		 * once it's printed.
 69		 */
 70		estatus->block_status = 0;
 71
 72		estatus = (void *)estatus + estatus_len;
 73		/* No more error records. */
 74		if (!estatus->block_status)
 75			return;
 76
 77		remain -= estatus_len;
 78	}
 79}
 80
 81static int __init setup_bert_disable(char *str)
 82{
 83	bert_disable = 1;
 84
 85	return 0;
 86}
 87__setup("bert_disable", setup_bert_disable);
 88
 89static int __init bert_check_table(struct acpi_table_bert *bert_tab)
 90{
 91	if (bert_tab->header.length < sizeof(struct acpi_table_bert) ||
 92	    bert_tab->region_length < sizeof(struct acpi_bert_region))
 93		return -EINVAL;
 94
 95	return 0;
 96}
 97
 98static int __init bert_init(void)
 99{
100	struct apei_resources bert_resources;
101	struct acpi_bert_region *boot_error_region;
102	struct acpi_table_bert *bert_tab;
103	unsigned int region_len;
104	acpi_status status;
105	int rc = 0;
106
107	if (acpi_disabled)
108		return 0;
109
110	if (bert_disable) {
111		pr_info("Boot Error Record Table support is disabled.\n");
112		return 0;
113	}
114
115	status = acpi_get_table(ACPI_SIG_BERT, 0, (struct acpi_table_header **)&bert_tab);
116	if (status == AE_NOT_FOUND)
117		return 0;
118
119	if (ACPI_FAILURE(status)) {
120		pr_err("get table failed, %s.\n", acpi_format_exception(status));
121		return -EINVAL;
122	}
123
124	rc = bert_check_table(bert_tab);
125	if (rc) {
126		pr_err(FW_BUG "table invalid.\n");
127		return rc;
128	}
129
130	region_len = bert_tab->region_length;
131	apei_resources_init(&bert_resources);
132	rc = apei_resources_add(&bert_resources, bert_tab->address,
133				region_len, true);
134	if (rc)
135		return rc;
136	rc = apei_resources_request(&bert_resources, "APEI BERT");
137	if (rc)
138		goto out_fini;
139	boot_error_region = ioremap_cache(bert_tab->address, region_len);
140	if (boot_error_region) {
141		bert_print_all(boot_error_region, region_len);
142		iounmap(boot_error_region);
143	} else {
144		rc = -ENOMEM;
145	}
146
147	apei_resources_release(&bert_resources);
148out_fini:
149	apei_resources_fini(&bert_resources);
150
151	return rc;
152}
153
154late_initcall(bert_init);