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authorLeo Yan <leo.yan@linaro.org>2021-08-09 14:14:00 +0300
committerMathieu Poirier <mathieu.poirier@linaro.org>2021-10-27 20:44:36 +0300
commit26701ceb4c2c6bfa5f8c8984fa1a1ea08fa0f02c (patch)
tree1a6e53f4871c2945f0d165b66569a1d274a526e5 /drivers/hwtracing
parent4d5d88baa6c838bf92ed6a63c50dd3167c5a4956 (diff)
downloadlinux-26701ceb4c2c6bfa5f8c8984fa1a1ea08fa0f02c.tar.xz
coresight: tmc-etr: Add barrier after updating AUX ring buffer
Since a memory barrier is required between AUX trace data store and aux_head store, and the AUX trace data is filled with memcpy(), it's sufficient to use smp_wmb() so can ensure the trace data is visible prior to updating aux_head. Signed-off-by: Leo Yan <leo.yan@linaro.org> Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com> Link: https://lore.kernel.org/r/20210809111407.596077-3-leo.yan@linaro.org Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Diffstat (limited to 'drivers/hwtracing')
-rw-r--r--drivers/hwtracing/coresight/coresight-tmc-etr.c8
1 files changed, 8 insertions, 0 deletions
diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c
index 0ac2a611110b..7f4654b72314 100644
--- a/drivers/hwtracing/coresight/coresight-tmc-etr.c
+++ b/drivers/hwtracing/coresight/coresight-tmc-etr.c
@@ -1564,6 +1564,14 @@ tmc_update_etr_buffer(struct coresight_device *csdev,
*/
if (etr_perf->snapshot)
handle->head += size;
+
+ /*
+ * Ensure that the AUX trace data is visible before the aux_head
+ * is updated via perf_aux_output_end(), as expected by the
+ * perf ring buffer.
+ */
+ smp_wmb();
+
out:
/*
* Don't set the TRUNCATED flag in snapshot mode because 1) the