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Rob Herring
e201260081
Like x86, some users may want to disable userspace PMU counter altogether. Add a sysctl 'perf_user_access' file to control userspace counter access. The default is '0' which is disabled. Writing '1' enables access. Note that x86 supports globally enabling user access by writing '2' to /sys/bus/event_source/devices/cpu/rdpmc. As there's not existing userspace support to worry about, this shouldn't be necessary for Arm. It could be added later if the need arises. Cc: Peter Zijlstra <[email protected]> Cc: Ingo Molnar <[email protected]> Cc: Arnaldo Carvalho de Melo <[email protected]> Cc: Alexander Shishkin <[email protected]> Cc: Jiri Olsa <[email protected]> Cc: Namhyung Kim <[email protected]> Cc: Catalin Marinas <[email protected]> Cc: [email protected] Acked-by: Will Deacon <[email protected]> Reviewed-by: Mark Rutland <[email protected]> Signed-off-by: Rob Herring <[email protected]> Link: https://lore.kernel.org/r/[email protected] Signed-off-by: Will Deacon <[email protected]>