3 files changed, 177 insertions, 11 deletions

diff --git a/arch/x86/kernel/cpu/mcheck/mce-apei.c b/arch/x86/kernel/cpu/mcheck/mce-apei.c
index 4eccd1fadb1..745b54f9be8 100644
--- a/arch/x86/kernel/cpu/mcheck/mce-apei.c
+++ b/arch/x86/kernel/cpu/mcheck/mce-apei.c
@@ -8,6 +8,9 @@
  * 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>
  *
@@ -50,3 +53,86 @@ void apei_mce_report_mem_error(int corrected, struct cper_sec_mem_err *mem_err)
         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_SER_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_SER_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;
+        ssize_t len;
+
+        len = erst_read_next(&rcd.hdr, sizeof(rcd));
+        if (len <= 0)
+                return len;
+        /* Can not skip other records in storage via ERST unless clear them */
+        else if (len != sizeof(rcd) ||
+                 uuid_le_cmp(rcd.hdr.creator_id, CPER_CREATOR_MCE)) {
+                if (printk_ratelimit())
+                        pr_warning(
+                        "MCE-APEI: Can not skip the unknown record in ERST");
+                return -EIO;
+        }
+
+        memcpy(m, &rcd.mce, sizeof(*m));
+        *record_id = rcd.hdr.record_id;
+
+        return sizeof(*m);
+}
+
+/* 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);
+}
diff --git a/arch/x86/kernel/cpu/mcheck/mce-internal.h b/arch/x86/kernel/cpu/mcheck/mce-internal.h
index 32996f9fab6..fefcc69ee8b 100644
--- a/arch/x86/kernel/cpu/mcheck/mce-internal.h
+++ b/arch/x86/kernel/cpu/mcheck/mce-internal.h
@@ -28,3 +28,26 @@ extern int mce_ser;
 
 extern struct mce_bank *mce_banks;
 
+#ifdef CONFIG_ACPI_APEI
+int apei_write_mce(struct mce *m);
+ssize_t apei_read_mce(struct mce *m, u64 *record_id);
+int apei_check_mce(void);
+int apei_clear_mce(u64 record_id);
+#else
+static inline int apei_write_mce(struct mce *m)
+{
+        return -EINVAL;
+}
+static inline ssize_t apei_read_mce(struct mce *m, u64 *record_id)
+{
+        return 0;
+}
+static inline int apei_check_mce(void)
+{
+        return 0;
+}
+static inline int apei_clear_mce(u64 record_id)
+{
+        return -EINVAL;
+}
+#endif
diff --git a/arch/x86/kernel/cpu/mcheck/mce.c b/arch/x86/kernel/cpu/mcheck/mce.c
index 8a6f0afa767..09535ca9b9d 100644
--- a/arch/x86/kernel/cpu/mcheck/mce.c
+++ b/arch/x86/kernel/cpu/mcheck/mce.c
@@ -264,7 +264,7 @@ static void wait_for_panic(void)
 
 static void mce_panic(char *msg, struct mce *final, char *exp)
 {
-        int i;
+        int i, apei_err = 0;
 
         if (!fake_panic) {
                 /*
@@ -287,8 +287,11 @@ static void mce_panic(char *msg, struct mce *final, char *exp)
                 struct mce *m = &mcelog.entry[i];
                 if (!(m->status & MCI_STATUS_VAL))
                         continue;
-                if (!(m->status & MCI_STATUS_UC))
+                if (!(m->status & MCI_STATUS_UC)) {
                         print_mce(m);
+                        if (!apei_err)
+                                apei_err = apei_write_mce(m);
+                }
         }
         /* Now print uncorrected but with the final one last */
         for (i = 0; i < MCE_LOG_LEN; i++) {
@@ -297,11 +300,17 @@ static void mce_panic(char *msg, struct mce *final, char *exp)
                         continue;
                 if (!(m->status & MCI_STATUS_UC))
                         continue;
-                if (!final || memcmp(m, final, sizeof(struct mce)))
+                if (!final || memcmp(m, final, sizeof(struct mce))) {
                         print_mce(m);
+                        if (!apei_err)
+                                apei_err = apei_write_mce(m);
+                }
         }
-        if (final)
+        if (final) {
                 print_mce(final);
+                if (!apei_err)
+                        apei_err = apei_write_mce(final);
+        }
         if (cpu_missing)
                 printk(KERN_EMERG "Some CPUs didn't answer in synchronization\n");
         print_mce_tail();
@@ -1493,6 +1502,43 @@ static void collect_tscs(void *data)
         rdtscll(cpu_tsc[smp_processor_id()]);
 }
 
+static int mce_apei_read_done;
+
+/* Collect MCE record of previous boot in persistent storage via APEI ERST. */
+static int __mce_read_apei(char __user **ubuf, size_t usize)
+{
+        int rc;
+        u64 record_id;
+        struct mce m;
+
+        if (usize < sizeof(struct mce))
+                return -EINVAL;
+
+        rc = apei_read_mce(&m, &record_id);
+        /* Error or no more MCE record */
+        if (rc <= 0) {
+                mce_apei_read_done = 1;
+                return rc;
+        }
+        rc = -EFAULT;
+        if (copy_to_user(*ubuf, &m, sizeof(struct mce)))
+                return rc;
+        /*
+         * In fact, we should have cleared the record after that has
+         * been flushed to the disk or sent to network in
+         * /sbin/mcelog, but we have no interface to support that now,
+         * so just clear it to avoid duplication.
+         */
+        rc = apei_clear_mce(record_id);
+        if (rc) {
+                mce_apei_read_done = 1;
+                return rc;
+        }
+        *ubuf += sizeof(struct mce);
+
+        return 0;
+}
+
 static ssize_t mce_read(struct file *filp, char __user *ubuf, size_t usize,
                         loff_t *off)
 {
@@ -1506,15 +1552,19 @@ static ssize_t mce_read(struct file *filp, char __user *ubuf, size_t usize,
                 return -ENOMEM;
 
         mutex_lock(&mce_read_mutex);
+
+        if (!mce_apei_read_done) {
+                err = __mce_read_apei(&buf, usize);
+                if (err || buf != ubuf)
+                        goto out;
+        }
+
         next = rcu_dereference_check_mce(mcelog.next);
 
         /* Only supports full reads right now */
-        if (*off != 0 || usize < MCE_LOG_LEN*sizeof(struct mce)) {
-                mutex_unlock(&mce_read_mutex);
-                kfree(cpu_tsc);
-
-                return -EINVAL;
-        }
+        err = -EINVAL;
+        if (*off != 0 || usize < MCE_LOG_LEN*sizeof(struct mce))
+                goto out;
 
         err = 0;
         prev = 0;
@@ -1562,10 +1612,15 @@ timeout:
                         memset(&mcelog.entry[i], 0, sizeof(struct mce));
                 }
         }
+
+        if (err)
+                err = -EFAULT;
+
+out:
         mutex_unlock(&mce_read_mutex);
         kfree(cpu_tsc);
 
-        return err ? -EFAULT : buf - ubuf;
+        return err ? err : buf - ubuf;
 }
 
 static unsigned int mce_poll(struct file *file, poll_table *wait)
@@ -1573,6 +1628,8 @@ static unsigned int mce_poll(struct file *file, poll_table *wait)
         poll_wait(file, &mce_wait, wait);
         if (rcu_dereference_check_mce(mcelog.next))
                 return POLLIN | POLLRDNORM;
+        if (!mce_apei_read_done && apei_check_mce())
+                return POLLIN | POLLRDNORM;
         return 0;
 }