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/*
* Debug Store support - selftest
*
*
* Copyright (C) 2009 Intel Corporation.
* Markus Metzger <markus.t.metzger@intel.com>, 2009
*/
#include "ds_selftest.h"
#include <linux/kernel.h>
#include <linux/string.h>
#include <asm/ds.h>
#define DS_SELFTEST_BUFFER_SIZE 1021 /* Intentionally chose an odd size. */
static int ds_selftest_bts_consistency(const struct bts_trace *trace)
{
int error = 0;
if (!trace) {
printk(KERN_CONT "failed to access trace...");
/* Bail out. Other tests are pointless. */
return -1;
}
if (!trace->read) {
printk(KERN_CONT "bts read not available...");
error = -1;
}
/* Do some sanity checks on the trace configuration. */
if (!trace->ds.n) {
printk(KERN_CONT "empty bts buffer...");
error = -1;
}
if (!trace->ds.size) {
printk(KERN_CONT "bad bts trace setup...");
error = -1;
}
if (trace->ds.end !=
(char *)trace->ds.begin + (trace->ds.n * trace->ds.size)) {
printk(KERN_CONT "bad bts buffer setup...");
error = -1;
}
if ((trace->ds.top < trace->ds.begin) ||
(trace->ds.end <= trace->ds.top)) {
printk(KERN_CONT "bts top out of bounds...");
error = -1;
}
return error;
}
static int ds_selftest_bts_read(struct bts_tracer *tracer,
const struct bts_trace *trace,
const void *from, const void *to)
{
const unsigned char *at;
/*
* Check a few things which do not belong to this test.
* They should be covered by other tests.
*/
if (!trace)
return -1;
if (!trace->read)
return -1;
if (to < from)
return -1;
if (from < trace->ds.begin)
return -1;
if (trace->ds.end < to)
return -1;
if (!trace->ds.size)
return -1;
/* Now to the test itself. */
for (at = from; (void *)at < to; at += trace->ds.size) {
struct bts_struct bts;
size_t index;
int error;
if (((void *)at - trace->ds.begin) % trace->ds.size) {
printk(KERN_CONT
"read from non-integer index...");
return -1;
}
index = ((void *)at - trace->ds.begin) / trace->ds.size;
memset(&bts, 0, sizeof(bts));
error = trace->read(tracer, at, &bts);
if (error < 0) {
printk(KERN_CONT
"error reading bts trace at [%lu] (0x%p)...",
index, at);
return error;
}
switch (bts.qualifier) {
case BTS_BRANCH:
break;
default:
printk(KERN_CONT
"unexpected bts entry %llu at [%lu] (0x%p)...",
bts.qualifier, index, at);
return -1;
}
}
return 0;
}
int ds_selftest_bts(void)
{
const struct bts_trace *trace;
struct bts_tracer *tracer;
int error = 0;
void *top;
unsigned char buffer[DS_SELFTEST_BUFFER_SIZE];
printk(KERN_INFO "[ds] bts selftest...");
tracer = ds_request_bts(NULL, buffer, DS_SELFTEST_BUFFER_SIZE,
NULL, (size_t)-1, BTS_KERNEL);
if (IS_ERR(tracer)) {
error = PTR_ERR(tracer);
tracer = NULL;
printk(KERN_CONT
"initialization failed (err: %d)...", error);
goto out;
}
/* The return should already give us enough trace. */
ds_suspend_bts(tracer);
/* Let's see if we can access the trace. */
trace = ds_read_bts(tracer);
error = ds_selftest_bts_consistency(trace);
if (error < 0)
goto out;
/* If everything went well, we should have a few trace entries. */
if (trace->ds.top == trace->ds.begin) {
/*
* It is possible but highly unlikely that we got a
* buffer overflow and end up at exactly the same
* position we started from.
* Let's issue a warning, but continue.
*/
printk(KERN_CONT "no trace/overflow...");
}
/* Let's try to read the trace we collected. */
error = ds_selftest_bts_read(tracer, trace,
trace->ds.begin, trace->ds.top);
if (error < 0)
goto out;
/*
* Let's read the trace again.
* Since we suspended tracing, we should get the same result.
*/
top = trace->ds.top;
trace = ds_read_bts(tracer);
error = ds_selftest_bts_consistency(trace);
if (error < 0)
goto out;
if (top != trace->ds.top) {
printk(KERN_CONT "suspend not working...");
error = -1;
goto out;
}
/* Let's collect some more trace - see if resume is working. */
ds_resume_bts(tracer);
ds_suspend_bts(tracer);
trace = ds_read_bts(tracer);
error = ds_selftest_bts_consistency(trace);
if (error < 0)
goto out;
if (trace->ds.top == top) {
/*
* It is possible but highly unlikely that we got a
* buffer overflow and end up at exactly the same
* position we started from.
* Let's issue a warning and check the full trace.
*/
printk(KERN_CONT
"no resume progress/overflow...");
error = ds_selftest_bts_read(tracer, trace,
trace->ds.begin, trace->ds.end);
} else if (trace->ds.top < top) {
/*
* We had a buffer overflow - the entire buffer should
* contain trace records.
*/
error = ds_selftest_bts_read(tracer, trace,
trace->ds.begin, trace->ds.end);
} else {
/*
* It is quite likely that the buffer did not overflow.
* Let's just check the delta trace.
*/
error = ds_selftest_bts_read(tracer, trace,
top, trace->ds.top);
}
if (error < 0)
goto out;
error = 0;
/* The final test: release the tracer while tracing is suspended. */
out:
ds_release_bts(tracer);
printk(KERN_CONT "%s.\n", (error ? "failed" : "passed"));
return error;
}
int ds_selftest_pebs(void)
{
return 0;
}
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