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Commit 01f6569e authored by Markus Metzger's avatar Markus Metzger Committed by Ingo Molnar
Browse files

x86, ds: selftest each cpu 



Perform debug store selftests on each cpu.

Cover both the normal and the _noirq variant of the debug store interface.

Signed-off-by: default avatarMarkus Metzger <markus.t.metzger@intel.com>
Cc: roland@redhat.com
Cc: eranian@googlemail.com
Cc: oleg@redhat.com
Cc: juan.villacis@intel.com
Cc: ak@linux.jf.intel.com
LKML-Reference: <20090403144559.394583000@intel.com>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 84f20113

arch/x86/kernel/ds_selftest.c

+135 −47
Original line number Diff line number Diff line
@@ -11,13 +11,21 @@ 
#include <linux/kernel.h>

#include <linux/string.h>

#include <linux/smp.h>

#include <linux/cpu.h>



#include <asm/ds.h>





#define BUFFER_SIZE 1021 /* Intentionally chose an odd size. */

#define BUFFER_SIZE	521 /* Intentionally chose an odd size. */





struct ds_selftest_bts_conf {

	struct bts_tracer *tracer;

	int error;

	int (*suspend)(struct bts_tracer *);

	int (*resume)(struct bts_tracer *);

};



static int ds_selftest_bts_consistency(const struct bts_trace *trace)

{

	int error = 0;
@@ -125,36 +133,32 @@ static int ds_selftest_bts_read(struct bts_tracer *tracer, 
	return 0;

}



int ds_selftest_bts(void)

static void ds_selftest_bts_cpu(void *arg)

{

	struct ds_selftest_bts_conf *conf = arg;

	const struct bts_trace *trace;

	struct bts_tracer *tracer;

	int error = 0;

	void *top;

	unsigned char buffer[BUFFER_SIZE];



	printk(KERN_INFO "[ds] bts selftest...");



	tracer = ds_request_bts_cpu(smp_processor_id(), buffer, BUFFER_SIZE,

				    NULL, (size_t)-1, BTS_KERNEL);

	if (IS_ERR(tracer)) {

		error = PTR_ERR(tracer);

		tracer = NULL;

	if (IS_ERR(conf->tracer)) {

		conf->error = PTR_ERR(conf->tracer);

		conf->tracer = NULL;



		printk(KERN_CONT

		       "initialization failed (err: %d)...", error);

		goto out;

		       "initialization failed (err: %d)...", conf->error);

		return;

	}



	/* The return should already give us enough trace. */

	ds_suspend_bts(tracer);

	/* We should meanwhile have enough trace. */

	conf->error = conf->suspend(conf->tracer);

	if (conf->error < 0)

		return;



	/* Let's see if we can access the trace. */

	trace = ds_read_bts(tracer);

	trace = ds_read_bts(conf->tracer);



	error = ds_selftest_bts_consistency(trace);

	if (error < 0)

		goto out;

	conf->error = ds_selftest_bts_consistency(trace);

	if (conf->error < 0)

		return;



	/* If everything went well, we should have a few trace entries. */

	if (trace->ds.top == trace->ds.begin) {
@@ -168,10 +172,11 @@ int ds_selftest_bts(void) 
	}



	/* Let's try to read the trace we collected. */

	error = ds_selftest_bts_read(tracer, trace,

	conf->error =

		ds_selftest_bts_read(conf->tracer, trace,

				     trace->ds.begin, trace->ds.top);

	if (error < 0)

		goto out;

	if (conf->error < 0)

		return;



	/*

	 * Let's read the trace again.
@@ -179,26 +184,31 @@ int ds_selftest_bts(void) 
	 */

	top = trace->ds.top;



	trace = ds_read_bts(tracer);

	error = ds_selftest_bts_consistency(trace);

	if (error < 0)

		goto out;

	trace = ds_read_bts(conf->tracer);

	conf->error = ds_selftest_bts_consistency(trace);

	if (conf->error < 0)

		return;



	if (top != trace->ds.top) {

		printk(KERN_CONT "suspend not working...");

		error = -1;

		goto out;

		conf->error = -1;

		return;

	}



	/* Let's collect some more trace - see if resume is working. */

	ds_resume_bts(tracer);

	ds_suspend_bts(tracer);

	conf->error = conf->resume(conf->tracer);

	if (conf->error < 0)

		return;



	trace = ds_read_bts(tracer);

	conf->error = conf->suspend(conf->tracer);

	if (conf->error < 0)

		return;



	error = ds_selftest_bts_consistency(trace);

	if (error < 0)

		goto out;

	trace = ds_read_bts(conf->tracer);



	conf->error = ds_selftest_bts_consistency(trace);

	if (conf->error < 0)

		return;



	if (trace->ds.top == top) {

		/*
@@ -210,35 +220,113 @@ int ds_selftest_bts(void) 
		printk(KERN_CONT

		       "no resume progress/overflow...");



		error = ds_selftest_bts_read(tracer, trace,

		conf->error =

			ds_selftest_bts_read(conf->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,

		conf->error =

			ds_selftest_bts_read(conf->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);

		conf->error =

			ds_selftest_bts_read(conf->tracer, trace, top,

					     trace->ds.top);

	}

	if (conf->error < 0)

		return;



	conf->error = 0;

}



static int ds_suspend_bts_wrap(struct bts_tracer *tracer)

{

	ds_suspend_bts(tracer);

	return 0;

}



static int ds_resume_bts_wrap(struct bts_tracer *tracer)

{

	ds_resume_bts(tracer);

	return 0;

}



static void ds_release_bts_noirq_wrap(void *tracer)

{

	(void)ds_release_bts_noirq(tracer);

}



static int ds_selftest_bts_bad_release_noirq(int cpu,

					     struct bts_tracer *tracer)

{

	int error = -EPERM;



	/* Try to release the tracer on the wrong cpu. */

	get_cpu();

	if (cpu != smp_processor_id()) {

		error = ds_release_bts_noirq(tracer);

		if (error != -EPERM)

			printk(KERN_CONT "release on wrong cpu...");

	}

	put_cpu();



	return error ? 0 : -1;

}

	if (error < 0)



int ds_selftest_bts(void)

{

	struct ds_selftest_bts_conf conf;

	unsigned char buffer[BUFFER_SIZE];

	int cpu;



	printk(KERN_INFO "[ds] bts selftest...");

	conf.error = 0;



	get_online_cpus();

	for_each_online_cpu(cpu) {

		conf.suspend = ds_suspend_bts_wrap;

		conf.resume = ds_resume_bts_wrap;

		conf.tracer =

			ds_request_bts_cpu(cpu, buffer, BUFFER_SIZE,

					   NULL, (size_t)-1, BTS_KERNEL);

		ds_selftest_bts_cpu(&conf);

		ds_release_bts(conf.tracer);

		if (conf.error < 0)

			goto out;



	error = 0;

		conf.suspend = ds_suspend_bts_noirq;

		conf.resume = ds_resume_bts_noirq;

		conf.tracer =

			ds_request_bts_cpu(cpu, buffer, BUFFER_SIZE,

					   NULL, (size_t)-1, BTS_KERNEL);

		smp_call_function_single(cpu, ds_selftest_bts_cpu, &conf, 1);

		if (conf.error >= 0) {

			conf.error =

				ds_selftest_bts_bad_release_noirq(cpu,

								  conf.tracer);

			/* We must not release the tracer twice. */

			if (conf.error < 0)

				conf.tracer = NULL;

		}

		smp_call_function_single(cpu, ds_release_bts_noirq_wrap,

					 conf.tracer, 1);

		if (conf.error < 0)

			goto out;

	}



	/* The final test: release the tracer while tracing is suspended. */

	conf.error = 0;

 out:

	ds_release_bts(tracer);



	printk(KERN_CONT "%s.\n", (error ? "failed" : "passed"));

	put_online_cpus();

	printk(KERN_CONT "%s.\n", (conf.error ? "failed" : "passed"));



	return error;

	return conf.error;

}



int ds_selftest_pebs(void)