1 files changed, 68 insertions, 11 deletions

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;
 }