According to the technical reference manual, the Cortex-A9
has a Perfomance Unit Monitor (PMU):
https://developer.arm.com/documentation/100511/0401/performance-monitoring-unit/about-the-performance-monitoring-unit
The Cortex-A8 does also.
We already already define the PMU registers when emulating the
Cortex-A8 and Cortex-A9, because we put them in v7_cp_reginfo[]
rather than guarding them behind ARM_FEATURE_PMU. So the only thing
that setting the feature bit changes is that the registers actually
do something.
Enable ARM_FEATURE_PMU for Cortex-A8 and Cortex-A9, to avoid
this anomaly.
(The A8 and A9 PMU predates the standardisation of ID_DFR0.PerfMon,
so the field there is 0, but the PMU is still present.)
Signed-off-by: Nikita Ostrenkov <n.ostrenkov@gmail.com>
Message-id: 20231112165658.2335-1-n.ostrenkov@gmail.com
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
[PMM: tweaked commit message; also enable PMU for A8]
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
FEAT_HPMN0 is a small feature which defines that it is valid for
MDCR_EL2.HPMN to be set to 0, meaning "no PMU event counters provided
to an EL1 guest" (previously this setting was reserved). QEMU's
implementation almost gets HPMN == 0 right, but we need to fix
one check in pmevcntr_is_64_bit(). That is enough for us to
advertise the feature in the 'max' CPU.
(We don't need to make the behaviour conditional on feature
presence, because the FEAT_HPMN0 behaviour is within the range
of permitted UNPREDICTABLE behaviour for a non-FEAT_HPMN0
implementation.)
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-id: 20230921185445.3339214-1-peter.maydell@linaro.org
