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Commit 3994a5c1 authored by Arve Hjønnevåg's avatar Arve Hjønnevåg Committed by Ruchi Kandoi
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ARM: etm: Add some missing locks and error checks 



It is not safe to call etm_lock or etb_lock without holding the
mutex since another thread may also have unlocked the registers.

Also add some missing checks for valid etb_regs in the etm sysfs
entries.

Change-Id: I939f76a6ea7546a8fc0d4ddafa2fd2b6f38103bb
Signed-off-by: default avatarArve Hjønnevåg <arve@android.com>
parent ae815d26

arch/arm/kernel/etm.c

+39 −18
Original line number Diff line number Diff line
@@ -264,8 +264,13 @@ static void etm_dump(void) 


static void sysrq_etm_dump(int key)

{

	if (!mutex_trylock(&tracer.mutex)) {

		printk(KERN_INFO "Tracing hardware busy\n");

		return;

	}

	dev_dbg(tracer.dev, "Dumping ETB buffer\n");

	etm_dump();

	mutex_unlock(&tracer.mutex);

}



static struct sysrq_key_op sysrq_etm_op = {
@@ -374,6 +379,7 @@ static int etb_probe(struct amba_device *dev, const struct amba_id *id) 
	if (ret)

		goto out;



	mutex_lock(&t->mutex);

	t->etb_regs = ioremap_nocache(dev->res.start, resource_size(&dev->res));

	if (!t->etb_regs) {

		ret = -ENOMEM;
@@ -382,6 +388,16 @@ static int etb_probe(struct amba_device *dev, const struct amba_id *id) 


	amba_set_drvdata(dev, t);



	etb_unlock(t);

	t->etb_bufsz = etb_readl(t, ETBR_DEPTH);

	dev_dbg(&dev->dev, "Size: %x\n", t->etb_bufsz);



	/* make sure trace capture is disabled */

	etb_writel(t, 0, ETBR_CTRL);

	etb_writel(t, 0x1000, ETBR_FORMATTERCTRL);

	etb_lock(t);

	mutex_unlock(&t->mutex);



	etb_miscdev.parent = &dev->dev;



	ret = misc_register(&etb_miscdev);
@@ -395,24 +411,18 @@ static int etb_probe(struct amba_device *dev, const struct amba_id *id) 
	else

		clk_enable(t->emu_clk);



	etb_unlock(t);

	t->etb_bufsz = etb_readl(t, ETBR_DEPTH);

	dev_dbg(&dev->dev, "Size: %x\n", t->etb_bufsz);



	/* make sure trace capture is disabled */

	etb_writel(t, 0, ETBR_CTRL);

	etb_writel(t, 0x1000, ETBR_FORMATTERCTRL);

	etb_lock(t);



	dev_dbg(&dev->dev, "ETB AMBA driver initialized.\n");



out:

	return ret;



out_unmap:

	mutex_lock(&t->mutex);

	iounmap(t->etb_regs);

	t->etb_regs = NULL;



out_release:

	mutex_unlock(&t->mutex);

	amba_release_regions(dev);



	return ret;
@@ -472,6 +482,9 @@ static ssize_t trace_running_store(struct kobject *kobj, 
		return -EINVAL;



	mutex_lock(&tracer.mutex);

	if (!tracer.etb_regs)

		ret = -ENODEV;

	else

		ret = value ? trace_start(&tracer) : trace_stop(&tracer);

	mutex_unlock(&tracer.mutex);
@@ -488,6 +501,8 @@ static ssize_t trace_info_show(struct kobject *kobj, 
	u32 etb_wa, etb_ra, etb_st, etb_fc, etm_ctrl, etm_st;

	int datalen;



	mutex_lock(&tracer.mutex);

	if (tracer.etb_regs) {

		etb_unlock(&tracer);

		datalen = etb_getdatalen(&tracer);

		etb_wa = etb_readl(&tracer, ETBR_WRITEADDR);
@@ -495,11 +510,16 @@ static ssize_t trace_info_show(struct kobject *kobj, 
		etb_st = etb_readl(&tracer, ETBR_STATUS);

		etb_fc = etb_readl(&tracer, ETBR_FORMATTERCTRL);

		etb_lock(&tracer);

	} else {

		etb_wa = etb_ra = etb_st = etb_fc = ~0;

		datalen = -1;

	}



	etm_unlock(&tracer);

	etm_ctrl = etm_readl(&tracer, ETMR_CTRL);

	etm_st = etm_readl(&tracer, ETMR_STATUS);

	etm_lock(&tracer);

	mutex_unlock(&tracer.mutex);



	return sprintf(buf, "Trace buffer len: %d\nComparator pairs: %d\n"

			"ETBR_WRITEADDR:\t%08x\n"
@@ -649,7 +669,6 @@ static int etm_probe(struct amba_device *dev, const struct amba_id *id) 


	amba_set_drvdata(dev, t);



	mutex_init(&t->mutex);

	t->dev = &dev->dev;

	t->flags = TRACER_CYCLE_ACC | TRACER_TRACE_DATA;

	t->etm_portsz = 1;
@@ -740,6 +759,8 @@ static int __init etm_init(void) 
{

	int retval;



	mutex_init(&tracer.mutex);



	retval = amba_driver_register(&etb_driver);

	if (retval) {

		printk(KERN_ERR "Failed to register etb\n");