coresight: tmc-etr: Fix updating buffer in not-snapshot mode.

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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.

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>
Link: https://lore.kernel.org/r/20190829202842.580-14-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

...

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Yabin Cui 2019-08-29 14:28:38 -06:00 • committed by Greg Kroah-Hartman

parent 89e89b05ef

commit 13af88f312

1 changed files with 11 additions and 7 deletions

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drivers/hwtracing/coresight/coresight-tmc-etr.c

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