Messages in this thread Patch in this message | | | Date | Mon, 5 Aug 2019 16:37:38 -0700 | Subject | [PATCH] coresight: tmc-etr: Fix updating buffer in not-snapshot mode. | From | Yabin Cui <> |
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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.
Signed-off-by: Yabin Cui <yabinc@google.com> --- drivers/hwtracing/coresight/coresight-tmc-etr.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-)
diff --git a/drivers/hwtracing/coresight/coresight-tmc-etr.c b/drivers/hwtracing/coresight/coresight-tmc-etr.c index 17006705287a..697e68d492af 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; @@ -1423,7 +1424,6 @@ static void tmc_etr_sync_perf_buffer(struct etr_perf_buffer *etr_perf) pg_offset = head & (PAGE_SIZE - 1); dst_pages = (char **)etr_perf->pages; src_offset = etr_buf->offset; - to_copy = etr_buf->len; while (to_copy > 0) { /* @@ -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 -- 2.22.0.770.g0f2c4a37fd-goog
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