+static size_t erst_reader(u64 *id, enum pstore_type_id *type,
+ struct timespec *time);
+static u64 erst_writer(enum pstore_type_id type, size_t size);
+
+static struct pstore_info erst_info = {
+ .owner = THIS_MODULE,
+ .name = "erst",
+ .read = erst_reader,
+ .write = erst_writer,
+ .erase = erst_clear
+};
+
+#define CPER_CREATOR_PSTORE \
+ UUID_LE(0x75a574e3, 0x5052, 0x4b29, 0x8a, 0x8e, 0xbe, 0x2c, \
+ 0x64, 0x90, 0xb8, 0x9d)
+#define CPER_SECTION_TYPE_DMESG \
+ UUID_LE(0xc197e04e, 0xd545, 0x4a70, 0x9c, 0x17, 0xa5, 0x54, \
+ 0x94, 0x19, 0xeb, 0x12)
+#define CPER_SECTION_TYPE_MCE \
+ UUID_LE(0xfe08ffbe, 0x95e4, 0x4be7, 0xbc, 0x73, 0x40, 0x96, \
+ 0x04, 0x4a, 0x38, 0xfc)
+
+struct cper_pstore_record {
+ struct cper_record_header hdr;
+ struct cper_section_descriptor sec_hdr;
+ char data[];
+} __packed;
+
+static size_t erst_reader(u64 *id, enum pstore_type_id *type,
+ struct timespec *time)
+{
+ int rc;
+ ssize_t len;
+ unsigned long flags;
+ u64 record_id;
+ struct cper_pstore_record *rcd = (struct cper_pstore_record *)
+ (erst_info.buf - sizeof(*rcd));
+
+ if (erst_disable)
+ return -ENODEV;
+
+ raw_spin_lock_irqsave(&erst_lock, flags);
+skip:
+ rc = __erst_get_next_record_id(&record_id);
+ if (rc) {
+ raw_spin_unlock_irqrestore(&erst_lock, flags);
+ return rc;
+ }
+ /* no more record */
+ if (record_id == APEI_ERST_INVALID_RECORD_ID) {
+ raw_spin_unlock_irqrestore(&erst_lock, flags);
+ return 0;
+ }
+
+ len = __erst_read(record_id, &rcd->hdr, sizeof(*rcd) +
+ erst_erange.size);
+ if (uuid_le_cmp(rcd->hdr.creator_id, CPER_CREATOR_PSTORE) != 0)
+ goto skip;
+ raw_spin_unlock_irqrestore(&erst_lock, flags);
+
+ *id = record_id;
+ if (uuid_le_cmp(rcd->sec_hdr.section_type,
+ CPER_SECTION_TYPE_DMESG) == 0)
+ *type = PSTORE_TYPE_DMESG;
+ else if (uuid_le_cmp(rcd->sec_hdr.section_type,
+ CPER_SECTION_TYPE_MCE) == 0)
+ *type = PSTORE_TYPE_MCE;
+ else
+ *type = PSTORE_TYPE_UNKNOWN;
+
+ if (rcd->hdr.validation_bits & CPER_VALID_TIMESTAMP)
+ time->tv_sec = rcd->hdr.timestamp;
+ else
+ time->tv_sec = 0;
+ time->tv_nsec = 0;
+
+ return len - sizeof(*rcd);
+}
+
+static u64 erst_writer(enum pstore_type_id type, size_t size)
+{
+ struct cper_pstore_record *rcd = (struct cper_pstore_record *)
+ (erst_info.buf - sizeof(*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 valid. platform_id, partition_id are invalid */
+ rcd->hdr.validation_bits = CPER_VALID_TIMESTAMP;
+ rcd->hdr.timestamp = get_seconds();
+ rcd->hdr.record_length = sizeof(*rcd) + size;
+ rcd->hdr.creator_id = CPER_CREATOR_PSTORE;
+ 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 = sizeof(*rcd);
+ rcd->sec_hdr.section_length = size;
+ 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;
+ switch (type) {
+ case PSTORE_TYPE_DMESG:
+ rcd->sec_hdr.section_type = CPER_SECTION_TYPE_DMESG;
+ break;
+ case PSTORE_TYPE_MCE:
+ rcd->sec_hdr.section_type = CPER_SECTION_TYPE_MCE;
+ break;
+ default:
+ return -EINVAL;
+ }
+ rcd->sec_hdr.section_severity = CPER_SEV_FATAL;
+
+ erst_write(&rcd->hdr);
+
+ return rcd->hdr.record_id;
+}
+