Enable PID_IN_CONTEXTIDR by default when Arm SPE is enabled. This flag is required to get PID data in the SPE trace. Without it the perf tool will report 0 for PID which isn't very useful, especially when doing system wide profiling or profiling applications that fork.
There is a small performance overhead when enabling PID_IN_CONTEXTIDR, but SPE itself is optional and not enabled by default so the impact is minimised. Cc: Will Deacon <[email protected]> Cc: Mark Rutland <[email protected]> Cc: Al Grant <[email protected]> Cc: Leo Yan <[email protected]> Cc: John Garry <[email protected]> Cc: Suzuki K Poulose <[email protected]> Cc: Mathieu Poirier <[email protected]> Cc: Catalin Marinas <[email protected]> Signed-off-by: James Clark <[email protected]> --- arch/arm64/Kconfig.debug | 1 + 1 file changed, 1 insertion(+) diff --git a/arch/arm64/Kconfig.debug b/arch/arm64/Kconfig.debug index 265c4461031f..b030bb21a0bb 100644 --- a/arch/arm64/Kconfig.debug +++ b/arch/arm64/Kconfig.debug @@ -2,6 +2,7 @@ config PID_IN_CONTEXTIDR bool "Write the current PID to the CONTEXTIDR register" + default y if ARM_SPE_PMU help Enabling this option causes the kernel to write the current PID to the CONTEXTIDR register, at the expense of some additional -- 2.28.0
