coresight: etm3x: Don't trace PID for non-root PID namespace

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ETMv3 driver enables PID tracing by directly using perf config from
userspace, this means the tracer will capture PID packets from root
namespace but the profiling session runs in non-root PID namespace.
Finally, the recorded packets can mislead perf reporting with the
mismatched PID values.

This patch changes to only enable PID tracing for root PID namespace.
Note, the hardware supports VMID tracing from ETMv3.5, but the driver
never enables VMID trace, this patch doesn't handle VMID trace (bit 30
in ETMCR register) particularly.

Signed-off-by: Leo Yan <leo.yan@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20220204152403.71775-5-leo.yan@linaro.org

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Leo Yan 2022-02-04 23:24:03 +08:00 • committed by Suzuki K Poulose

parent aab473867f

commit ec70b05d5d

1 changed files with 4 additions and 0 deletions

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drivers/hwtracing/coresight/coresight-etm3x-core.c

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