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/*
* 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;
}
}
#ifdef CONFIG_DEBUG_FS
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,
.llseek = seq_lseek,
};
static int __init severities_debugfs_init(void)
{
struct dentry *dmce = NULL, *fseverities_coverage = NULL;
dmce = mce_get_debugfs_dir();
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:
return -ENOMEM;
}
late_initcall(severities_debugfs_init);
#endif
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