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coresight: tmc: Explicit type conversions to prevent integer overflow

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[ Upstream commit fd380097cd ]

Perf cs_etm session executed unexpectedly when AUX buffer > 1G.

  perf record -C 0 -m ,2G -e cs_etm// -- <workload>
  [ perf record: Captured and wrote 2.615 MB perf.data ]

Perf only collect about 2M perf data rather than 2G. This is becasuse
the operation, "nr_pages << PAGE_SHIFT", in coresight tmc driver, will
overflow when nr_pages >= 0x80000(correspond to 1G AUX buffer). The
overflow cause buffer allocation to fail, and TMC driver will alloc
minimal buffer size(1M). You can just get about 2M perf data(1M AUX
buffer + perf data header) at least.

Explicit convert nr_pages to 64 bit to avoid overflow.

Fixes: 22f429f19c ("coresight: etm-perf: Add support for ETR backend")
Fixes: 99443ea19e ("coresight: Add generic TMC sg table framework")
Fixes: 2e499bbc1a ("coresight: tmc: implementing TMC-ETF AUX space API")
Signed-off-by: Ruidong Tian <tianruidong@linux.alibaba.com>
Reviewed-by: James Clark <james.clark@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20230804081514.120171-2-tianruidong@linux.alibaba.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Ruidong Tian 2023-08-04 16:15:14 +08:00 • committed by Greg Kroah-Hartman
commit 7e1476f277
3 changed files with 5 additions and 4 deletions
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