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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 MCESEV(s, m, c...) { .sev = MCE_ ## s ## _SEVERITY, .msg = m, ## c }
#define KERNEL .context = IN_KERNEL
#define USER .context = IN_USER
#define SER .ser = SER_REQUIRED
#define NOSER .ser = NO_SER
#define BITCLR(x) .mask = x, .result = 0
#define BITSET(x) .mask = x, .result = x
#define MCGMASK(x, y) .mcgmask = x, .mcgres = y
#define MASK(x, y) .mask = x, .result = y
#define MCI_UC_S (MCI_STATUS_UC|MCI_STATUS_S)
#define MCI_UC_SAR (MCI_STATUS_UC|MCI_STATUS_S|MCI_STATUS_AR)
#define MCI_ADDR (MCI_STATUS_ADDRV|MCI_STATUS_MISCV)
MCESEV(
NO, "Invalid",
BITCLR(MCI_STATUS_VAL)
),
MCESEV(
NO, "Not enabled",
BITCLR(MCI_STATUS_EN)
),
MCESEV(
PANIC, "Processor context corrupt",
BITSET(MCI_STATUS_PCC)
),
/* When MCIP is not set something is very confused */
MCESEV(
PANIC, "MCIP not set in MCA handler",
MCGMASK(MCG_STATUS_MCIP, 0)
),
/* Neither return not error IP -- no chance to recover -> PANIC */
MCESEV(
PANIC, "Neither restart nor error IP",
MCGMASK(MCG_STATUS_RIPV|MCG_STATUS_EIPV, 0)
),
MCESEV(
PANIC, "In kernel and no restart IP",
KERNEL, MCGMASK(MCG_STATUS_RIPV, 0)
),
MCESEV(
KEEP, "Corrected error",
NOSER, BITCLR(MCI_STATUS_UC)
),
/* ignore OVER for UCNA */
MCESEV(
KEEP, "Uncorrected no action required",
SER, MASK(MCI_UC_SAR, MCI_STATUS_UC)
),
MCESEV(
PANIC, "Illegal combination (UCNA with AR=1)",
SER,
MASK(MCI_STATUS_OVER|MCI_UC_SAR, MCI_STATUS_UC|MCI_STATUS_AR)
),
MCESEV(
KEEP, "Non signalled machine check",
SER, BITCLR(MCI_STATUS_S)
),
MCESEV(
PANIC, "Action required with lost events",
SER, BITSET(MCI_STATUS_OVER|MCI_UC_SAR)
),
/* known AR MCACODs: */
#ifdef CONFIG_MEMORY_FAILURE
MCESEV(
KEEP, "Action required but unaffected thread is continuable",
SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR|MCI_ADDR, MCI_UC_SAR|MCI_ADDR),
MCGMASK(MCG_STATUS_RIPV|MCG_STATUS_EIPV, MCG_STATUS_RIPV)
),
MCESEV(
AR, "Action required: data load error in a user process",
SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR|MCI_ADDR|MCACOD, MCI_UC_SAR|MCI_ADDR|MCACOD_DATA),
USER
),
MCESEV(
AR, "Action required: instruction fetch error in a user process",
SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR|MCI_ADDR|MCACOD, MCI_UC_SAR|MCI_ADDR|MCACOD_INSTR),
USER
),
#endif
MCESEV(
PANIC, "Action required: unknown MCACOD",
SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR, MCI_UC_SAR)
),
/* known AO MCACODs: */
MCESEV(
AO, "Action optional: memory scrubbing error",
SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR|MCACOD_SCRUBMSK, MCI_UC_S|MCACOD_SCRUB)
),
MCESEV(
AO, "Action optional: last level cache writeback error",
SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR|MCACOD, MCI_UC_S|MCACOD_L3WB)
),
MCESEV(
SOME, "Action optional: unknown MCACOD",
SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR, MCI_UC_S)
),
MCESEV(
SOME, "Action optional with lost events",
SER, MASK(MCI_STATUS_OVER|MCI_UC_SAR, MCI_STATUS_OVER|MCI_UC_S)
),
MCESEV(
PANIC, "Overflowed uncorrected",
BITSET(MCI_STATUS_OVER|MCI_STATUS_UC)
),
MCESEV(
UC, "Uncorrected",
BITSET(MCI_STATUS_UC)
),
MCESEV(
SOME, "No match",
BITSET(0)
) /* always matches. keep at end */
};
/*
* If mcgstatus indicated that ip/cs on the stack were
* no good, then "m->cs" will be zero and we will have
* to assume the worst case (IN_KERNEL) as we actually
* have no idea what we were executing when the machine
* check hit.
* If we do have a good "m->cs" (or a faked one in the
* case we were executing in VM86 mode) we can use it to
* distinguish an exception taken in user from from one
* taken in the kernel.
*/
static int error_context(struct mce *m)
{
return ((m->cs & 3) == 3) ? IN_USER : IN_KERNEL;
}
int mce_severity(struct mce *m, int tolerant, char **msg)
{
enum context ctx = error_context(m);
struct severity *s;
for (s = severities;; s++) {
if ((m->status & s->mask) != s->result)
continue;
if ((m->mcgstatus & s->mcgmask) != s->mcgres)
continue;
if (s->ser == SER_REQUIRED && !mca_cfg.ser)
continue;
if (s->ser == NO_SER && mca_cfg.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, *fsev;
dmce = mce_get_debugfs_dir();
if (!dmce)
goto err_out;
fsev = debugfs_create_file("severities-coverage", 0444, dmce, NULL,
&severities_coverage_fops);
if (!fsev)
goto err_out;
return 0;
err_out:
return -ENOMEM;
}
late_initcall(severities_debugfs_init);
#endif /* CONFIG_DEBUG_FS */