release/5.2.47/coresight-tmc-etr-Fix-perf_data-check.patch

From 2088b4f0d8bb38e4b3f7f7f02e7f892df88cdd8f Mon Sep 17 00:00:00 2001
From: Yabin Cui <yabinc@google.com>
Date: Thu, 29 Aug 2019 14:28:39 -0600
Subject: [PATCH] coresight: tmc-etr: Fix perf_data check

commit bbedcb91cc3bf252e6031e199ab3d1f07107f7c5 upstream.

When tracing etm data of multiple threads on multiple cpus through
perf interface, each cpu has a unique etr_perf_buffer while sharing
the same etr device. There is no guarantee that the last cpu starts
etm tracing also stops last. This makes perf_data check fail.

Fix it by checking etr_buf instead of etr_perf_buffer.
Also move the code setting and clearing perf_buf to more suitable
places.

Fixes: 3147da92a8a8 ("coresight: tmc-etr: Allocate and free ETR memory buffers for CPU-wide scenarios")
Signed-off-by: Yabin Cui <yabinc@google.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20190829202842.580-15-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c
index 9f293b9dce8c..614c749ab511 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etr.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c
@@ -1476,7 +1476,7 @@ tmc_update_etr_buffer(struct coresight_device *csdev,
 		goto out;
 	}
 
-	if (WARN_ON(drvdata->perf_data != etr_perf)) {
+	if (WARN_ON(drvdata->perf_buf != etr_buf)) {
 		lost = true;
 		spin_unlock_irqrestore(&drvdata->spinlock, flags);
 		goto out;
@@ -1488,8 +1488,6 @@ tmc_update_etr_buffer(struct coresight_device *csdev,
 	tmc_sync_etr_buf(drvdata);
 
 	CS_LOCK(drvdata->base);
-	/* Reset perf specific data */
-	drvdata->perf_data = NULL;
 	spin_unlock_irqrestore(&drvdata->spinlock, flags);
 
 	size = etr_buf->len;
@@ -1543,7 +1541,6 @@ static int tmc_enable_etr_sink_perf(struct coresight_device *csdev, void *data)
 	}
 
 	etr_perf->head = PERF_IDX2OFF(handle->head, etr_perf);
-	drvdata->perf_data = etr_perf;
 
 	/*
 	 * No HW configuration is needed if the sink is already in
@@ -1559,6 +1556,7 @@ static int tmc_enable_etr_sink_perf(struct coresight_device *csdev, void *data)
 		/* Associate with monitored process. */
 		drvdata->pid = pid;
 		drvdata->mode = CS_MODE_PERF;
+		drvdata->perf_buf = etr_perf->etr_buf;
 		atomic_inc(csdev->refcnt);
 	}
 
@@ -1604,6 +1602,8 @@ static int tmc_disable_etr_sink(struct coresight_device *csdev)
 	/* Dissociate from monitored process. */
 	drvdata->pid = -1;
 	drvdata->mode = CS_MODE_DISABLED;
+	/* Reset perf specific data */
+	drvdata->perf_buf = NULL;
 
 	spin_unlock_irqrestore(&drvdata->spinlock, flags);
 
diff --git a/drivers/hwtracing/coresight/coresight-tmc.h b/drivers/hwtracing/coresight/coresight-tmc.h
index 503f1b3a3741..97b3415847e2 100644
--- a/drivers/hwtracing/coresight/coresight-tmc.h
+++ b/drivers/hwtracing/coresight/coresight-tmc.h
@@ -179,8 +179,8 @@ struct etr_buf {
  *		device configuration register (DEVID)
  * @idr:	Holds etr_bufs allocated for this ETR.
  * @idr_mutex:	Access serialisation for idr.
- * @perf_data:	PERF buffer for ETR.
- * @sysfs_data:	SYSFS buffer for ETR.
+ * @sysfs_buf:	SYSFS buffer for ETR.
+ * @perf_buf:	PERF buffer for ETR.
  */
 struct tmc_drvdata {
 	void __iomem		*base;
@@ -204,7 +204,7 @@ struct tmc_drvdata {
 	struct idr		idr;
 	struct mutex		idr_mutex;
 	struct etr_buf		*sysfs_buf;
-	void			*perf_data;
+	struct etr_buf		*perf_buf;
 };
 
 struct etr_buf_operations {
-- 
2.27.0