0211bf43ce
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 <peterz@infradead.org> Cc: Ingo Molnar <mingo@redhat.com> Cc: Arnaldo Carvalho de Melo <acme@kernel.org> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com> Cc: Jiri Olsa <jolsa@redhat.com> Cc: Namhyung Kim <namhyung@kernel.org> Cc: Catalin Marinas <catalin.marinas@arm.com> Cc: linux-perf-users@vger.kernel.org Acked-by: Will Deacon <will@kernel.org> Reviewed-by: Mark Rutland <mark.rutland@arm.com> Signed-off-by: Rob Herring <robh@kernel.org> Link: https://lore.kernel.org/r/20211208201124.310740-4-robh@kernel.org Signed-off-by: Will Deacon <will@kernel.org> Bug: 230559577 (cherry picked from commit e2012600810c9ded81f6f63a8d04781be3c300ad) Change-Id: Iea14f96122992944e1d97b9f6f6f821d54c1def1 Signed-off-by: Srinivasarao Pathipati <quic_spathi@quicinc.com>