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Commit c38a9ec2 authored by Mathieu Poirier's avatar Mathieu Poirier Committed by Greg Kroah-Hartman
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coresight: etm4x: moving etm_drvdata::enable to atomic field 



Similarly to ETMv3, moving etmv4_drvdata::enable to an atomic
type that gives the 'mode' of a tracer and prevents multiple,
simultanious access by different subsystems.

Signed-off-by: default avatarMathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 66bbbb77

drivers/hwtracing/coresight/coresight-etm4x.c

+60 −9
Original line number Diff line number Diff line
@@ -34,6 +34,7 @@ 
#include <linux/pm_runtime.h>

#include <linux/perf_event.h>

#include <asm/sections.h>

#include <asm/local.h>



#include "coresight-etm4x.h"
@@ -76,7 +77,7 @@ static int etm4_trace_id(struct coresight_device *csdev) 
	unsigned long flags;

	int trace_id = -1;



	if (!drvdata->enable)

	if (!local_read(&drvdata->mode))

		return drvdata->trcid;



	spin_lock_irqsave(&drvdata->spinlock, flags);
@@ -188,8 +189,7 @@ static void etm4_enable_hw(void *info) 
	dev_dbg(drvdata->dev, "cpu: %d enable smp call done\n", drvdata->cpu);

}



static int etm4_enable(struct coresight_device *csdev,

		       struct perf_event_attr *attr, u32 mode)

static int etm4_enable_sysfs(struct coresight_device *csdev)

{

	struct etmv4_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);

	int ret;
@@ -204,18 +204,46 @@ static int etm4_enable(struct coresight_device *csdev, 
				       etm4_enable_hw, drvdata, 1);

	if (ret)

		goto err;

	drvdata->enable = true;

	drvdata->sticky_enable = true;



	drvdata->sticky_enable = true;

	spin_unlock(&drvdata->spinlock);



	dev_info(drvdata->dev, "ETM tracing enabled\n");

	return 0;



err:

	spin_unlock(&drvdata->spinlock);

	return ret;

}



static int etm4_enable(struct coresight_device *csdev,

		       struct perf_event_attr *attr, u32 mode)

{

	int ret;

	u32 val;

	struct etmv4_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);



	val = local_cmpxchg(&drvdata->mode, CS_MODE_DISABLED, mode);



	/* Someone is already using the tracer */

	if (val)

		return -EBUSY;



	switch (mode) {

	case CS_MODE_SYSFS:

		ret = etm4_enable_sysfs(csdev);

		break;

	default:

		ret = -EINVAL;

	}



	/* The tracer didn't start */

	if (ret)

		local_set(&drvdata->mode, CS_MODE_DISABLED);



	return ret;

}



static void etm4_disable_hw(void *info)

{

	u32 control;
@@ -238,7 +266,7 @@ static void etm4_disable_hw(void *info) 
	dev_dbg(drvdata->dev, "cpu: %d disable smp call done\n", drvdata->cpu);

}



static void etm4_disable(struct coresight_device *csdev)

static void etm4_disable_sysfs(struct coresight_device *csdev)

{

	struct etmv4_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);
@@ -256,7 +284,6 @@ static void etm4_disable(struct coresight_device *csdev) 
	 * ensures that register writes occur when cpu is powered.

	 */

	smp_call_function_single(drvdata->cpu, etm4_disable_hw, drvdata, 1);

	drvdata->enable = false;



	spin_unlock(&drvdata->spinlock);

	put_online_cpus();
@@ -264,6 +291,30 @@ static void etm4_disable(struct coresight_device *csdev) 
	dev_info(drvdata->dev, "ETM tracing disabled\n");

}



static void etm4_disable(struct coresight_device *csdev)

{

	u32 mode;

	struct etmv4_drvdata *drvdata = dev_get_drvdata(csdev->dev.parent);



	/*

	 * For as long as the tracer isn't disabled another entity can't

	 * change its status.  As such we can read the status here without

	 * fearing it will change under us.

	 */

	mode = local_read(&drvdata->mode);



	switch (mode) {

	case CS_MODE_DISABLED:

		break;

	case CS_MODE_SYSFS:

		etm4_disable_sysfs(csdev);

		break;

	}



	if (mode)

		local_set(&drvdata->mode, CS_MODE_DISABLED);

}



static const struct coresight_ops_source etm4_source_ops = {

	.cpu_id		= etm4_cpu_id,

	.trace_id	= etm4_trace_id,
@@ -531,7 +582,7 @@ static int etm4_cpu_callback(struct notifier_block *nfb, unsigned long action, 
			etmdrvdata[cpu]->os_unlock = true;

		}



		if (etmdrvdata[cpu]->enable)

		if (local_read(&etmdrvdata[cpu]->mode))

			etm4_enable_hw(etmdrvdata[cpu]);

		spin_unlock(&etmdrvdata[cpu]->spinlock);

		break;
@@ -544,7 +595,7 @@ static int etm4_cpu_callback(struct notifier_block *nfb, unsigned long action, 


	case CPU_DYING:

		spin_lock(&etmdrvdata[cpu]->spinlock);

		if (etmdrvdata[cpu]->enable)

		if (local_read(&etmdrvdata[cpu]->mode))

			etm4_disable_hw(etmdrvdata[cpu]);

		spin_unlock(&etmdrvdata[cpu]->spinlock);

		break;

drivers/hwtracing/coresight/coresight-etm4x.h

+3 −2
Original line number Diff line number Diff line
@@ -13,6 +13,7 @@ 
#ifndef _CORESIGHT_CORESIGHT_ETM_H

#define _CORESIGHT_CORESIGHT_ETM_H



#include <asm/local.h>

#include <linux/spinlock.h>

#include "coresight-priv.h"
@@ -290,6 +291,7 @@ struct etmv4_config { 
 * @dev:        The device entity associated to this component.

 * @csdev:      Component vitals needed by the framework.

 * @spinlock:   Only one at a time pls.

 * @mode:	This tracer's mode, i.e sysFS, Perf or disabled.

 * @cpu:        The cpu this component is affined to.

 * @arch:       ETM version number.

 * @nr_pe:	The number of processing entity available for tracing.
@@ -316,7 +318,6 @@ struct etmv4_config { 
 *		supported for the corresponding Exception level.

 * @ns_ex_level:In non-secure state, indicates whether instruction tracing is

 *		supported for the corresponding Exception level.

 * @enable:	Is this ETM currently tracing.

 * @sticky_enable: true if ETM base configuration has been done.

 * @boot_enable:True if we should start tracing at boot time.

 * @os_unlock:  True if access to management registers is allowed.
@@ -346,6 +347,7 @@ struct etmv4_drvdata { 
	struct device			*dev;

	struct coresight_device		*csdev;

	spinlock_t			spinlock;

	local_t				mode;

	int				cpu;

	u8				arch;

	u8				nr_pe;
@@ -368,7 +370,6 @@ struct etmv4_drvdata { 
	u8				ccitmin;

	u8				s_ex_level;

	u8				ns_ex_level;

	bool				enable;

	bool				sticky_enable;

	bool				boot_enable;

	bool				os_unlock;