On Tue, Dec 02, 2025 at 12:05:52PM +0000, Suzuki K Poulose wrote:

On 01/12/2025 11:22, Leo Yan wrote:

quoted

The overwrite erratum occurs only on wrap events, so apply the extra
wrap condition check in the workaround.

Signed-off-by: Leo Yan <leo.yan@arm.com>
---
  drivers/hwtracing/coresight/coresight-trbe.c | 4 ++--
  1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/hwtracing/coresight/coresight-trbe.c b/drivers/hwtracing/coresight/coresight-trbe.c
index e579ea98523c24d23a0cd265dcdd0a46b52b52da..2600af12a8fb94bb8c74efda2a101aacd01b0b34 100644
--- a/drivers/hwtracing/coresight/coresight-trbe.c
+++ b/drivers/hwtracing/coresight/coresight-trbe.c

@@ -714,7 +714,7 @@ static unsigned long trbe_get_trace_size(struct perf_output_handle *handle,
  	 * 64bytes. Thus we ignore the potential triggering of the erratum
  	 * on WRAP and limit the data to LIMIT.
  	 */
-	if (wrap)
+	if (wrap && trbe_may_overwrite_in_fill_mode(buf->cpudata))
  		write = get_trbe_limit_pointer();

This must be trbe_may_write_out_of_range() ?

SDEN (e.g., [1]) is ambiguous about how the write pointer acts for the
out-of-range erratum.

However, SDEN explicitly states for overwrite erratum: "The current
write pointer also increments by the same number of cache line
locations.

If this is still concerned, I can add check
trbe_may_write_out_of_range() in next spin.

Thanks,
Leo

[1] https://documentation-service.arm.com/static/636a660b4e6cf12278ad89c4?token=