[PATCH 0/2] Coresight: Fix for v5.3-rc5

[PATCH 0/2] Coresight: Fix for v5.3-rc5

[Mathieu Poirier]

Good day,

Please see if you can add the following fix to the current cycle.  If
you think it is a little late I'll simply lump them with the set I
have for v5.4.

Applies cleanly to your char-misc-linus (d1abaeb3be7b) branch.

Thanks,
Mathieu 


Yabin Cui (2):
  coresight: tmc-etr: Fix updating buffer in not-snapshot mode
  coresight: tmc-etr: Fix perf_data check

 .../hwtracing/coresight/coresight-tmc-etr.c   | 26 +++++++++++--------
 drivers/hwtracing/coresight/coresight-tmc.h   |  6 ++---
 2 files changed, 18 insertions(+), 14 deletions(-)

-- 
2.17.1


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[PATCH 1/2] coresight: tmc-etr: Fix updating buffer in not-snapshot mode

[Mathieu Poirier]

From: Yabin Cui <yabinc@google.com>

TMC etr always copies all available data to perf aux buffer, which
may exceed the available space in perf aux buffer. It isn't suitable
for not-snapshot mode, because:
1) It may overwrite previously written data.
2) It may make the perf_event_mmap_page->aux_head report having more
or less data than the reality.

So change to only copy the latest data fitting the available space in
perf aux buffer.

Signed-off-by: Yabin Cui <yabinc@google.com>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
---
 .../hwtracing/coresight/coresight-tmc-etr.c    | 18 +++++++++++-------
 1 file changed, 11 insertions(+), 7 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c
index 17006705287a..676dcb4cf0e2 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etr.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c
@@ -1410,9 +1410,10 @@ static void tmc_free_etr_buffer(void *config)
  * tmc_etr_sync_perf_buffer: Copy the actual trace data from the hardware
  * buffer to the perf ring buffer.
  */
-static void tmc_etr_sync_perf_buffer(struct etr_perf_buffer *etr_perf)
+static void tmc_etr_sync_perf_buffer(struct etr_perf_buffer *etr_perf,
+				     unsigned long to_copy)
 {
-	long bytes, to_copy;
+	long bytes;
 	long pg_idx, pg_offset, src_offset;
 	unsigned long head = etr_perf->head;
 	char **dst_pages, *src_buf;
@@ -1422,8 +1423,7 @@ static void tmc_etr_sync_perf_buffer(struct etr_perf_buffer *etr_perf)
 	pg_idx = head >> PAGE_SHIFT;
 	pg_offset = head & (PAGE_SIZE - 1);
 	dst_pages = (char **)etr_perf->pages;
-	src_offset = etr_buf->offset;
-	to_copy = etr_buf->len;
+	src_offset = etr_buf->offset + etr_buf->len - to_copy;
 
 	while (to_copy > 0) {
 		/*
@@ -1434,6 +1434,8 @@ static void tmc_etr_sync_perf_buffer(struct etr_perf_buffer *etr_perf)
 		 *  3) what is available in the destination page.
 		 * in one iteration.
 		 */
+		if (src_offset >= etr_buf->size)
+			src_offset -= etr_buf->size;
 		bytes = tmc_etr_buf_get_data(etr_buf, src_offset, to_copy,
 					     &src_buf);
 		if (WARN_ON_ONCE(bytes <= 0))
@@ -1454,8 +1456,6 @@ static void tmc_etr_sync_perf_buffer(struct etr_perf_buffer *etr_perf)
 
 		/* Move source pointers */
 		src_offset += bytes;
-		if (src_offset >= etr_buf->size)
-			src_offset -= etr_buf->size;
 	}
 }
 
@@ -1501,7 +1501,11 @@ tmc_update_etr_buffer(struct coresight_device *csdev,
 	spin_unlock_irqrestore(&drvdata->spinlock, flags);
 
 	size = etr_buf->len;
-	tmc_etr_sync_perf_buffer(etr_perf);
+	if (!etr_perf->snapshot && size > handle->size) {
+		size = handle->size;
+		lost = true;
+	}
+	tmc_etr_sync_perf_buffer(etr_perf, size);
 
 	/*
 	 * In snapshot mode we simply increment the head by the number of byte
-- 
2.17.1


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[PATCH 2/2] coresight: tmc-etr: Fix perf_data check

[Mathieu Poirier]

From: Yabin Cui <yabinc@google.com>

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>
---
 drivers/hwtracing/coresight/coresight-tmc-etr.c | 8 ++++----
 drivers/hwtracing/coresight/coresight-tmc.h     | 6 +++---
 2 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c
index 676dcb4cf0e2..ba644f444d4c 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;
@@ -1496,8 +1496,6 @@ 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;
@@ -1560,7 +1558,6 @@ 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
@@ -1576,6 +1573,7 @@ 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);
 	}
 
@@ -1621,6 +1619,8 @@ 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 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 {
-- 
2.17.1


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Re: [PATCH 0/2] Coresight: Fix for v5.3-rc5

[Mathieu Poirier]

On Tue, 20 Aug 2019 at 13:41, Mathieu Poirier
<mathieu.poirier@linaro.org> wrote:
>
> Good day,
>
> Please see if you can add the following fix to the current cycle.  If
> you think it is a little late I'll simply lump them with the set I
> have for v5.4.

I found an issue with a corner case - please ignore this request.

>
> Applies cleanly to your char-misc-linus (d1abaeb3be7b) branch.
>
> Thanks,
> Mathieu
>
>
> Yabin Cui (2):
>   coresight: tmc-etr: Fix updating buffer in not-snapshot mode
>   coresight: tmc-etr: Fix perf_data check
>
>  .../hwtracing/coresight/coresight-tmc-etr.c   | 26 +++++++++++--------
>  drivers/hwtracing/coresight/coresight-tmc.h   |  6 ++---
>  2 files changed, 18 insertions(+), 14 deletions(-)
>
> --
> 2.17.1
>

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Re: [PATCH 0/2] Coresight: Fix for v5.3-rc5

[Greg KH]

On Wed, Aug 21, 2019 at 01:28:43PM -0600, Mathieu Poirier wrote:
> On Tue, 20 Aug 2019 at 13:41, Mathieu Poirier
> <mathieu.poirier@linaro.org> wrote:
> >
> > Good day,
> >
> > Please see if you can add the following fix to the current cycle.  If
> > you think it is a little late I'll simply lump them with the set I
> > have for v5.4.
> 
> I found an issue with a corner case - please ignore this request.

Now dropped, thanks.

greg k-h

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