[v4,5/6] coresight: Set and clear sink device handler for kdump node

Message ID 1522379724-30648-6-git-send-email-leo.yan@linaro.org
State New
Headers show
Series
  • Coresight: Support panic kdump
Related show

Commit Message

Leo Yan March 30, 2018, 3:15 a.m.
If Coresight path is enabled for specific CPU, the sink device handler
need to be set to kdump node; on the other hand we also need to clear
sink device handler when path is disabled.

This patch sets sink devices handler for kdump node for two separate
Coresight enabling modes: CS_MODE_SYSFS and CS_MODE_PERF; and clear the
handler when Coresight is disabled.

Signed-off-by: Leo Yan <leo.yan@linaro.org>

---
 drivers/hwtracing/coresight/coresight-etm-perf.c |  5 +++++
 drivers/hwtracing/coresight/coresight.c          | 16 ++++++++++++++--
 2 files changed, 19 insertions(+), 2 deletions(-)

-- 
2.7.4

Comments

Mathieu Poirier April 2, 2018, 9:34 p.m. | #1
On Fri, Mar 30, 2018 at 11:15:23AM +0800, Leo Yan wrote:
> If Coresight path is enabled for specific CPU, the sink device handler

> need to be set to kdump node; on the other hand we also need to clear

> sink device handler when path is disabled.

> 

> This patch sets sink devices handler for kdump node for two separate

> Coresight enabling modes: CS_MODE_SYSFS and CS_MODE_PERF; and clear the

> handler when Coresight is disabled.

> 

> Signed-off-by: Leo Yan <leo.yan@linaro.org>

> ---

>  drivers/hwtracing/coresight/coresight-etm-perf.c |  5 +++++

>  drivers/hwtracing/coresight/coresight.c          | 16 ++++++++++++++--

>  2 files changed, 19 insertions(+), 2 deletions(-)

> 

> diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c

> index 8a0ad77..f8b159c 100644

> --- a/drivers/hwtracing/coresight/coresight-etm-perf.c

> +++ b/drivers/hwtracing/coresight/coresight-etm-perf.c

> @@ -139,6 +139,8 @@ static void free_event_data(struct work_struct *work)

>  	for_each_cpu(cpu, mask) {

>  		if (!(IS_ERR_OR_NULL(event_data->path[cpu])))

>  			coresight_release_path(event_data->path[cpu]);

> +

> +		coresight_kdump_sink(cpu, NULL);

>  	}

>  

>  	kfree(event_data->path);

> @@ -238,6 +240,9 @@ static void *etm_setup_aux(int event_cpu, void **pages,

>  		event_data->path[cpu] = coresight_build_path(csdev, sink);

>  		if (IS_ERR(event_data->path[cpu]))

>  			goto err;

> +

> +		if (coresight_kdump_sink(cpu, sink))

> +			goto err;


I remember telling you to use free_event_data() and etm_setup_aux().  _Maybe_ it
made sense in the previous patchset but in this one it won't work.  We need to
reflect the current trace context, as such use etm_event_start() and
etm_event_stop().

In etm_event_start() call coresight_kdump_sink(cpu, sink) just before
source_ops(csdev)->enable().  Similarly call coresight_kdump_sink(cpu, NULL)
right after source_ops(csdev)->disable() in etm_event_stop().

Find me on IRC if you want more information on this.

>  	}

>  

>  	if (!sink_ops(sink)->alloc_buffer)

> diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c

> index 389c4ba..483a1f7 100644

> --- a/drivers/hwtracing/coresight/coresight.c

> +++ b/drivers/hwtracing/coresight/coresight.c

> @@ -272,6 +272,7 @@ static int coresight_enable_source(struct coresight_device *csdev, u32 mode)

>  static bool coresight_disable_source(struct coresight_device *csdev)

>  {

>  	if (atomic_dec_return(csdev->refcnt) == 0) {

> +


This newline shouldn't be part of this set.

>  		if (source_ops(csdev)->disable)

>  			source_ops(csdev)->disable(csdev, NULL);

>  		csdev->enable = false;

> @@ -612,6 +613,13 @@ int coresight_enable(struct coresight_device *csdev)

>  	if (ret)

>  		goto err_source;

>  

> +	cpu = source_ops(csdev)->cpu_id(csdev);

> +

> +	/* Set sink device handler into kdump node */

> +	ret = coresight_kdump_sink(cpu, sink);

> +	if (ret)

> +		goto err_kdump;

> +


Call coresight_kdump_sink() just before coresight_enable_source().  That way if
there is a dump just after coresight_enable_source() is called we get the chance
of getting some traces in the dump file. 

>  	switch (subtype) {

>  	case CORESIGHT_DEV_SUBTYPE_SOURCE_PROC:

>  		/*

> @@ -621,7 +629,6 @@ int coresight_enable(struct coresight_device *csdev)

>  		 * be a single session per tracer (when working from sysFS)

>  		 * a per-cpu variable will do just fine.

>  		 */

> -		cpu = source_ops(csdev)->cpu_id(csdev);

>  		per_cpu(tracer_path, cpu) = path;

>  		break;

>  	case CORESIGHT_DEV_SUBTYPE_SOURCE_SOFTWARE:

> @@ -636,6 +643,9 @@ int coresight_enable(struct coresight_device *csdev)

>  	mutex_unlock(&coresight_mutex);

>  	return ret;

>  

> +err_kdump:

> +	coresight_disable_source(csdev);

> +

>  err_source:

>  	coresight_disable_path(path);

>  

> @@ -659,9 +669,10 @@ void coresight_disable(struct coresight_device *csdev)

>  	if (!csdev->enable || !coresight_disable_source(csdev))

>  		goto out;

>  

> +	cpu = source_ops(csdev)->cpu_id(csdev);

> +

>  	switch (csdev->subtype.source_subtype) {

>  	case CORESIGHT_DEV_SUBTYPE_SOURCE_PROC:

> -		cpu = source_ops(csdev)->cpu_id(csdev);

>  		path = per_cpu(tracer_path, cpu);

>  		per_cpu(tracer_path, cpu) = NULL;

>  		break;

> @@ -674,6 +685,7 @@ void coresight_disable(struct coresight_device *csdev)

>  		break;

>  	}

>  

> +	coresight_kdump_sink(cpu, NULL);

>  	coresight_disable_path(path);

>  	coresight_release_path(path);

>  

> -- 

> 2.7.4

>

Patch

diff --git a/drivers/hwtracing/coresight/coresight-etm-perf.c b/drivers/hwtracing/coresight/coresight-etm-perf.c
index 8a0ad77..f8b159c 100644
--- a/drivers/hwtracing/coresight/coresight-etm-perf.c
+++ b/drivers/hwtracing/coresight/coresight-etm-perf.c
@@ -139,6 +139,8 @@  static void free_event_data(struct work_struct *work)
 	for_each_cpu(cpu, mask) {
 		if (!(IS_ERR_OR_NULL(event_data->path[cpu])))
 			coresight_release_path(event_data->path[cpu]);
+
+		coresight_kdump_sink(cpu, NULL);
 	}
 
 	kfree(event_data->path);
@@ -238,6 +240,9 @@  static void *etm_setup_aux(int event_cpu, void **pages,
 		event_data->path[cpu] = coresight_build_path(csdev, sink);
 		if (IS_ERR(event_data->path[cpu]))
 			goto err;
+
+		if (coresight_kdump_sink(cpu, sink))
+			goto err;
 	}
 
 	if (!sink_ops(sink)->alloc_buffer)
diff --git a/drivers/hwtracing/coresight/coresight.c b/drivers/hwtracing/coresight/coresight.c
index 389c4ba..483a1f7 100644
--- a/drivers/hwtracing/coresight/coresight.c
+++ b/drivers/hwtracing/coresight/coresight.c
@@ -272,6 +272,7 @@  static int coresight_enable_source(struct coresight_device *csdev, u32 mode)
 static bool coresight_disable_source(struct coresight_device *csdev)
 {
 	if (atomic_dec_return(csdev->refcnt) == 0) {
+
 		if (source_ops(csdev)->disable)
 			source_ops(csdev)->disable(csdev, NULL);
 		csdev->enable = false;
@@ -612,6 +613,13 @@  int coresight_enable(struct coresight_device *csdev)
 	if (ret)
 		goto err_source;
 
+	cpu = source_ops(csdev)->cpu_id(csdev);
+
+	/* Set sink device handler into kdump node */
+	ret = coresight_kdump_sink(cpu, sink);
+	if (ret)
+		goto err_kdump;
+
 	switch (subtype) {
 	case CORESIGHT_DEV_SUBTYPE_SOURCE_PROC:
 		/*
@@ -621,7 +629,6 @@  int coresight_enable(struct coresight_device *csdev)
 		 * be a single session per tracer (when working from sysFS)
 		 * a per-cpu variable will do just fine.
 		 */
-		cpu = source_ops(csdev)->cpu_id(csdev);
 		per_cpu(tracer_path, cpu) = path;
 		break;
 	case CORESIGHT_DEV_SUBTYPE_SOURCE_SOFTWARE:
@@ -636,6 +643,9 @@  int coresight_enable(struct coresight_device *csdev)
 	mutex_unlock(&coresight_mutex);
 	return ret;
 
+err_kdump:
+	coresight_disable_source(csdev);
+
 err_source:
 	coresight_disable_path(path);
 
@@ -659,9 +669,10 @@  void coresight_disable(struct coresight_device *csdev)
 	if (!csdev->enable || !coresight_disable_source(csdev))
 		goto out;
 
+	cpu = source_ops(csdev)->cpu_id(csdev);
+
 	switch (csdev->subtype.source_subtype) {
 	case CORESIGHT_DEV_SUBTYPE_SOURCE_PROC:
-		cpu = source_ops(csdev)->cpu_id(csdev);
 		path = per_cpu(tracer_path, cpu);
 		per_cpu(tracer_path, cpu) = NULL;
 		break;
@@ -674,6 +685,7 @@  void coresight_disable(struct coresight_device *csdev)
 		break;
 	}
 
+	coresight_kdump_sink(cpu, NULL);
 	coresight_disable_path(path);
 	coresight_release_path(path);