linux-kernel - [PATCH v2] coresight: tmc-etr: Fix perf

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Message-Id: <20190812190320.209988-1-yabinc@google.com>
Date:   Mon, 12 Aug 2019 12:03:20 -0700
From:   Yabin Cui <yabinc@...gle.com>
To:     Mathieu Poirier <mathieu.poirier@...aro.org>,
        Suzuki K Poulose <suzuki.poulose@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>
Cc:     linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Yabin Cui <yabinc@...gle.com>
Subject: [PATCH v2] coresight: tmc-etr: Fix perf_data check.

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.

Fixes: 3147da92a8a8 ("coresight: tmc-etr: Allocate and free ETR memory buffers for CPU-wide scenarios")
Signed-off-by: Yabin Cui <yabinc@...gle.com>
---

v1 -> v2: rename perf_data to perf_buf. Add fixes tag.

---
 drivers/hwtracing/coresight/coresight-tmc-etr.c | 6 +++---
 drivers/hwtracing/coresight/coresight-tmc.h     | 6 +++---
 2 files changed, 6 insertions(+), 6 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c
index 17006705287a..90d1548ad268 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etr.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c
@@ -1484,7 +1484,7 @@ 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;
@@ -1497,7 +1497,7 @@ tmc_update_etr_buffer(struct coresight_device *csdev,
 
 	CS_LOCK(drvdata->base);
 	/* Reset perf specific data */
-	drvdata->perf_data = NULL;
+	drvdata->perf_buf = NULL;
 	spin_unlock_irqrestore(&drvdata->spinlock, flags);
 
 	size = etr_buf->len;
@@ -1556,7 +1556,7 @@ 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;
+	drvdata->perf_buf = etr_perf->etr_buf;
 
 	/*
 	 * No HW configuration is needed if the sink is already in
diff --git a/drivers/hwtracing/coresight/coresight-tmc.h b/drivers/hwtracing/coresight/coresight-tmc.h
index 1ed50411cc3c..f9a0c95e9ba2 100644
--- a/drivers/hwtracing/coresight/coresight-tmc.h
+++ b/drivers/hwtracing/coresight/coresight-tmc.h
@@ -178,8 +178,8 @@ 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;
@@ -202,7 +202,7 @@ 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 {
-- 
2.23.0.rc1.153.gdeed80330f-goog