1 files changed, 218 insertions, 0 deletions

diff --git a/arch/x86/kernel/cpu/mcheck/mce-severity.c b/arch/x86/kernel/cpu/mcheck/mce-severity.c
new file mode 100644
index 000000000000..ff0807f97056
--- /dev/null
+++ b/arch/x86/kernel/cpu/mcheck/mce-severity.c
@@ -0,0 +1,218 @@
+/*
+ * MCE grading rules.
+ * Copyright 2008, 2009 Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License
+ * as published by the Free Software Foundation; version 2
+ * of the License.
+ *
+ * Author: Andi Kleen
+ */
+#include <linux/kernel.h>
+#include <linux/seq_file.h>
+#include <linux/init.h>
+#include <linux/debugfs.h>
+#include <asm/mce.h>
+
+#include "mce-internal.h"
+
+/*
+ * Grade an mce by severity. In general the most severe ones are processed
+ * first. Since there are quite a lot of combinations test the bits in a
+ * table-driven way. The rules are simply processed in order, first
+ * match wins.
+ *
+ * Note this is only used for machine check exceptions, the corrected
+ * errors use much simpler rules. The exceptions still check for the corrected
+ * errors, but only to leave them alone for the CMCI handler (except for
+ * panic situations)
+ */
+
+enum context { IN_KERNEL = 1, IN_USER = 2 };
+enum ser { SER_REQUIRED = 1, NO_SER = 2 };
+
+static struct severity {
+        u64 mask;
+        u64 result;
+        unsigned char sev;
+        unsigned char mcgmask;
+        unsigned char mcgres;
+        unsigned char ser;
+        unsigned char context;
+        unsigned char covered;
+        char *msg;
+} severities[] = {
+#define KERNEL .context = IN_KERNEL
+#define USER .context = IN_USER
+#define SER .ser = SER_REQUIRED
+#define NOSER .ser = NO_SER
+#define SEV(s) .sev = MCE_ ## s ## _SEVERITY
+#define BITCLR(x, s, m, r...) { .mask = x, .result = 0, SEV(s), .msg = m, ## r }
+#define BITSET(x, s, m, r...) { .mask = x, .result = x, SEV(s), .msg = m, ## r }
+#define MCGMASK(x, res, s, m, r...) \
+        { .mcgmask = x, .mcgres = res, SEV(s), .msg = m, ## r }
+#define MASK(x, y, s, m, r...) \
+        { .mask = x, .result = y, SEV(s), .msg = m, ## r }
+#define MCI_UC_S (MCI_STATUS_UC|MCI_STATUS_S)
+#define MCI_UC_SAR (MCI_STATUS_UC|MCI_STATUS_S|MCI_STATUS_AR)
+#define MCACOD 0xffff
+
+        BITCLR(MCI_STATUS_VAL, NO, "Invalid"),
+        BITCLR(MCI_STATUS_EN, NO, "Not enabled"),
+        BITSET(MCI_STATUS_PCC, PANIC, "Processor context corrupt"),
+        /* When MCIP is not set something is very confused */
+        MCGMASK(MCG_STATUS_MCIP, 0, PANIC, "MCIP not set in MCA handler"),
+        /* Neither return not error IP -- no chance to recover -> PANIC */
+        MCGMASK(MCG_STATUS_RIPV|MCG_STATUS_EIPV, 0, PANIC,
+                "Neither restart nor error IP"),
+        MCGMASK(MCG_STATUS_RIPV, 0, PANIC, "In kernel and no restart IP",
+                KERNEL),
+        BITCLR(MCI_STATUS_UC, KEEP, "Corrected error", NOSER),
+        MASK(MCI_STATUS_OVER|MCI_STATUS_UC|MCI_STATUS_EN, MCI_STATUS_UC, SOME,
+             "Spurious not enabled", SER),
+
+        /* ignore OVER for UCNA */
+        MASK(MCI_UC_SAR, MCI_STATUS_UC, KEEP,
+             "Uncorrected no action required", SER),
+        MASK(MCI_STATUS_OVER|MCI_UC_SAR, MCI_STATUS_UC|MCI_STATUS_AR, PANIC,
+             "Illegal combination (UCNA with AR=1)", SER),
+        MASK(MCI_STATUS_S, 0, KEEP, "Non signalled machine check", SER),
+
+        /* AR add known MCACODs here */
+        MASK(MCI_STATUS_OVER|MCI_UC_SAR, MCI_STATUS_OVER|MCI_UC_SAR, PANIC,
+             "Action required with lost events", SER),
+        MASK(MCI_STATUS_OVER|MCI_UC_SAR|MCACOD, MCI_UC_SAR, PANIC,
+             "Action required; unknown MCACOD", SER),
+
+        /* known AO MCACODs: */
+        MASK(MCI_UC_SAR|MCI_STATUS_OVER|0xfff0, MCI_UC_S|0xc0, AO,
+             "Action optional: memory scrubbing error", SER),
+        MASK(MCI_UC_SAR|MCI_STATUS_OVER|MCACOD, MCI_UC_S|0x17a, AO,
+             "Action optional: last level cache writeback error", SER),
+
+        MASK(MCI_STATUS_OVER|MCI_UC_SAR, MCI_UC_S, SOME,
+             "Action optional unknown MCACOD", SER),
+        MASK(MCI_STATUS_OVER|MCI_UC_SAR, MCI_UC_S|MCI_STATUS_OVER, SOME,
+             "Action optional with lost events", SER),
+        BITSET(MCI_STATUS_UC|MCI_STATUS_OVER, PANIC, "Overflowed uncorrected"),
+        BITSET(MCI_STATUS_UC, UC, "Uncorrected"),
+        BITSET(0, SOME, "No match")     /* always matches. keep at end */
+};
+
+/*
+ * If the EIPV bit is set, it means the saved IP is the
+ * instruction which caused the MCE.
+ */
+static int error_context(struct mce *m)
+{
+        if (m->mcgstatus & MCG_STATUS_EIPV)
+                return (m->ip && (m->cs & 3) == 3) ? IN_USER : IN_KERNEL;
+        /* Unknown, assume kernel */
+        return IN_KERNEL;
+}
+
+int mce_severity(struct mce *a, int tolerant, char **msg)
+{
+        enum context ctx = error_context(a);
+        struct severity *s;
+
+        for (s = severities;; s++) {
+                if ((a->status & s->mask) != s->result)
+                        continue;
+                if ((a->mcgstatus & s->mcgmask) != s->mcgres)
+                        continue;
+                if (s->ser == SER_REQUIRED && !mce_ser)
+                        continue;
+                if (s->ser == NO_SER && mce_ser)
+                        continue;
+                if (s->context && ctx != s->context)
+                        continue;
+                if (msg)
+                        *msg = s->msg;
+                s->covered = 1;
+                if (s->sev >= MCE_UC_SEVERITY && ctx == IN_KERNEL) {
+                        if (panic_on_oops || tolerant < 1)
+                                return MCE_PANIC_SEVERITY;
+                }
+                return s->sev;
+        }
+}
+
+static void *s_start(struct seq_file *f, loff_t *pos)
+{
+        if (*pos >= ARRAY_SIZE(severities))
+                return NULL;
+        return &severities[*pos];
+}
+
+static void *s_next(struct seq_file *f, void *data, loff_t *pos)
+{
+        if (++(*pos) >= ARRAY_SIZE(severities))
+                return NULL;
+        return &severities[*pos];
+}
+
+static void s_stop(struct seq_file *f, void *data)
+{
+}
+
+static int s_show(struct seq_file *f, void *data)
+{
+        struct severity *ser = data;
+        seq_printf(f, "%d\t%s\n", ser->covered, ser->msg);
+        return 0;
+}
+
+static const struct seq_operations severities_seq_ops = {
+        .start  = s_start,
+        .next   = s_next,
+        .stop   = s_stop,
+        .show   = s_show,
+};
+
+static int severities_coverage_open(struct inode *inode, struct file *file)
+{
+        return seq_open(file, &severities_seq_ops);
+}
+
+static ssize_t severities_coverage_write(struct file *file,
+                                         const char __user *ubuf,
+                                         size_t count, loff_t *ppos)
+{
+        int i;
+        for (i = 0; i < ARRAY_SIZE(severities); i++)
+                severities[i].covered = 0;
+        return count;
+}
+
+static const struct file_operations severities_coverage_fops = {
+        .open           = severities_coverage_open,
+        .release        = seq_release,
+        .read           = seq_read,
+        .write          = severities_coverage_write,
+};
+
+static int __init severities_debugfs_init(void)
+{
+        struct dentry *dmce = NULL, *fseverities_coverage = NULL;
+
+        dmce = debugfs_create_dir("mce", NULL);
+        if (dmce == NULL)
+                goto err_out;
+        fseverities_coverage = debugfs_create_file("severities-coverage",
+                                                   0444, dmce, NULL,
+                                                   &severities_coverage_fops);
+        if (fseverities_coverage == NULL)
+                goto err_out;
+
+        return 0;
+
+err_out:
+        if (fseverities_coverage)
+                debugfs_remove(fseverities_coverage);
+        if (dmce)
+                debugfs_remove(dmce);
+        return -ENOMEM;
+}
+late_initcall(severities_debugfs_init);