text: /*
   * Bridge between MCE and APEI
   *
   * On some machine, corrected memory errors are reported via APEI
   * generic hardware error source (GHES) instead of corrected Machine
   * Check. These corrected memory errors can be reported to user space
   * through /dev/mcelog via faking a corrected Machine Check, so that
   * the error memory page can be offlined by /sbin/mcelog if the error
   * count for one page is beyond the threshold.
   *
   * For fatal MCE, save MCE record into persistent storage via ERST, so
   * that the MCE record can be logged after reboot via ERST.
   *
   * Copyright 2010 Intel Corp.
   *   Author: Huang Ying <ying.huang@intel.com>
   *
   * This program is free software; you can redistribute it and/or
   * modify it under the terms of the GNU General Public License version
   * 2 as published by the Free Software Foundation.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
   */
  
  #include <linux/export.h>
  #include <linux/kernel.h>
  #include <linux/acpi.h>
  #include <linux/cper.h>
  #include <acpi/apei.h>
  #include <asm/mce.h>
  
  #include "mce-internal.h"
  
  void apei_mce_report_mem_error(int corrected, struct cper_sec_mem_err *mem_err)
  {
  	struct mce m;
  
  	/* Only corrected MC is reported */
  	if (!corrected || !(mem_err->validation_bits &
  				CPER_MEM_VALID_PHYSICAL_ADDRESS))
  		return;
  
  	mce_setup(&m);
  	m.bank = 1;
  	/* Fake a memory read corrected error with unknown channel */
  	m.status = MCI_STATUS_VAL | MCI_STATUS_EN | MCI_STATUS_ADDRV | 0x9f;
  	m.addr = mem_err->physical_addr;
  	mce_log(&m);
  	mce_notify_irq();
  }
  EXPORT_SYMBOL_GPL(apei_mce_report_mem_error);
  
  #define CPER_CREATOR_MCE						\
  	UUID_LE(0x75a574e3, 0x5052, 0x4b29, 0x8a, 0x8e, 0xbe, 0x2c,	\
  		0x64, 0x90, 0xb8, 0x9d)
  #define CPER_SECTION_TYPE_MCE						\
  	UUID_LE(0xfe08ffbe, 0x95e4, 0x4be7, 0xbc, 0x73, 0x40, 0x96,	\
  		0x04, 0x4a, 0x38, 0xfc)
  
  /*
   * CPER specification (in UEFI specification 2.3 appendix N) requires
   * byte-packed.
   */
  struct cper_mce_record {
  	struct cper_record_header hdr;
  	struct cper_section_descriptor sec_hdr;
  	struct mce mce;
  } __packed;
  
  int apei_write_mce(struct mce *m)
  {
  	struct cper_mce_record rcd;
  
  	memset(&rcd, 0, sizeof(rcd));
  	memcpy(rcd.hdr.signature, CPER_SIG_RECORD, CPER_SIG_SIZE);
  	rcd.hdr.revision = CPER_RECORD_REV;
  	rcd.hdr.signature_end = CPER_SIG_END;
  	rcd.hdr.section_count = 1;
  	rcd.hdr.error_severity = CPER_SEV_FATAL;
  	/* timestamp, platform_id, partition_id are all invalid */
  	rcd.hdr.validation_bits = 0;
  	rcd.hdr.record_length = sizeof(rcd);
  	rcd.hdr.creator_id = CPER_CREATOR_MCE;
  	rcd.hdr.notification_type = CPER_NOTIFY_MCE;
  	rcd.hdr.record_id = cper_next_record_id();
  	rcd.hdr.flags = CPER_HW_ERROR_FLAGS_PREVERR;
  
  	rcd.sec_hdr.section_offset = (void *)&rcd.mce - (void *)&rcd;
  	rcd.sec_hdr.section_length = sizeof(rcd.mce);
  	rcd.sec_hdr.revision = CPER_SEC_REV;
  	/* fru_id and fru_text is invalid */
  	rcd.sec_hdr.validation_bits = 0;
  	rcd.sec_hdr.flags = CPER_SEC_PRIMARY;
  	rcd.sec_hdr.section_type = CPER_SECTION_TYPE_MCE;
  	rcd.sec_hdr.section_severity = CPER_SEV_FATAL;
  
  	memcpy(&rcd.mce, m, sizeof(*m));
  
  	return erst_write(&rcd.hdr);
  }
  
  ssize_t apei_read_mce(struct mce *m, u64 *record_id)
  {
  	struct cper_mce_record rcd;
  	int rc, pos;
  
  	rc = erst_get_record_id_begin(&pos);
  	if (rc)
  		return rc;
  retry:
  	rc = erst_get_record_id_next(&pos, record_id);
  	if (rc)
  		goto out;
  	/* no more record */
  	if (*record_id == APEI_ERST_INVALID_RECORD_ID)
  		goto out;
  	rc = erst_read(*record_id, &rcd.hdr, sizeof(rcd));
  	/* someone else has cleared the record, try next one */
  	if (rc == -ENOENT)
  		goto retry;
  	else if (rc < 0)
  		goto out;
  	/* try to skip other type records in storage */
  	else if (rc != sizeof(rcd) ||
  		 uuid_le_cmp(rcd.hdr.creator_id, CPER_CREATOR_MCE))
  		goto retry;
  	memcpy(m, &rcd.mce, sizeof(*m));
  	rc = sizeof(*m);
  out:
  	erst_get_record_id_end();
  
  	return rc;
  }
  
  /* Check whether there is record in ERST */
  int apei_check_mce(void)
  {
  	return erst_get_record_count();
  }
  
  int apei_clear_mce(u64 record_id)
  {
  	return erst_clear(record_id);
  }
  