Commit 4611a6fa authored by Huang Ying's avatar Huang Ying Committed by H. Peter Anvin

x86, mce: export MCE severities coverage via debugfs

The MCE severity judgement code is data-driven, so code coverage tools
such as gcov can not be used for measuring coverage. Instead a dedicated
coverage mechanism is implemented.  The kernel keeps track of rules
executed and reports them in debugfs.

This is useful for increasing coverage of the mce-test testsuite.

Right now it's unconditionally enabled because it's very little code.
Signed-off-by: default avatarHuang Ying <ying.huang@intel.com>
Signed-off-by: default avatarAndi Kleen <ak@linux.intel.com>
Signed-off-by: default avatarHidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Signed-off-by: default avatarH. Peter Anvin <hpa@zytor.com>
parent ed7290d0
...@@ -10,6 +10,9 @@ ...@@ -10,6 +10,9 @@
* Author: Andi Kleen * Author: Andi Kleen
*/ */
#include <linux/kernel.h> #include <linux/kernel.h>
#include <linux/seq_file.h>
#include <linux/init.h>
#include <linux/debugfs.h>
#include <asm/mce.h> #include <asm/mce.h>
#include "mce-internal.h" #include "mce-internal.h"
...@@ -37,6 +40,7 @@ static struct severity { ...@@ -37,6 +40,7 @@ static struct severity {
unsigned char mcgres; unsigned char mcgres;
unsigned char ser; unsigned char ser;
unsigned char context; unsigned char context;
unsigned char covered;
char *msg; char *msg;
} severities[] = { } severities[] = {
#define KERNEL .context = IN_KERNEL #define KERNEL .context = IN_KERNEL
...@@ -126,6 +130,7 @@ int mce_severity(struct mce *a, int tolerant, char **msg) ...@@ -126,6 +130,7 @@ int mce_severity(struct mce *a, int tolerant, char **msg)
continue; continue;
if (msg) if (msg)
*msg = s->msg; *msg = s->msg;
s->covered = 1;
if (s->sev >= MCE_UC_SEVERITY && ctx == IN_KERNEL) { if (s->sev >= MCE_UC_SEVERITY && ctx == IN_KERNEL) {
if (panic_on_oops || tolerant < 1) if (panic_on_oops || tolerant < 1)
return MCE_PANIC_SEVERITY; return MCE_PANIC_SEVERITY;
...@@ -133,3 +138,81 @@ int mce_severity(struct mce *a, int tolerant, char **msg) ...@@ -133,3 +138,81 @@ int mce_severity(struct mce *a, int tolerant, char **msg)
return s->sev; 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);
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