On Tue, Jan 03, 2017 at 06:10:18PM +0000, Will Deacon wrote: > Perf already supports multiple PMU instances for heterogeneous systems, > so there's no need to be strict in the cpufeature checking, particularly > as the PMU extension is optional in the architecture. > > Reviewed-by: Suzuki K Poulose <[email protected]> > Signed-off-by: Will Deacon <[email protected]>
There are remaining issues with PMU support exposed to KVM guests in hetereogeneous systems, but I think that's a larger issue with KVM and heterogeneous CPUs (and we're already aware of it), so FWIW: Acked-by: Mark Rutland <[email protected]> Thanks, Mark. > --- > arch/arm64/kernel/cpufeature.c | 6 +++++- > 1 file changed, 5 insertions(+), 1 deletion(-) > > diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c > index fdf8f045929f..47d0226620e8 100644 > --- a/arch/arm64/kernel/cpufeature.c > +++ b/arch/arm64/kernel/cpufeature.c > @@ -184,7 +184,11 @@ static const struct arm64_ftr_bits ftr_id_aa64dfr0[] = { > ARM64_FTR_BITS(FTR_STRICT, FTR_LOWER_SAFE, ID_AA64DFR0_CTX_CMPS_SHIFT, > 4, 0), > ARM64_FTR_BITS(FTR_STRICT, FTR_LOWER_SAFE, ID_AA64DFR0_WRPS_SHIFT, 4, > 0), > ARM64_FTR_BITS(FTR_STRICT, FTR_LOWER_SAFE, ID_AA64DFR0_BRPS_SHIFT, 4, > 0), > - S_ARM64_FTR_BITS(FTR_STRICT, FTR_EXACT, ID_AA64DFR0_PMUVER_SHIFT, 4, 0), > + /* > + * We can instantiate multiple PMU instances with different levels > + * of support. > + * */ > + S_ARM64_FTR_BITS(FTR_NONSTRICT, FTR_EXACT, ID_AA64DFR0_PMUVER_SHIFT, 4, > 0), > ARM64_FTR_BITS(FTR_STRICT, FTR_EXACT, ID_AA64DFR0_TRACEVER_SHIFT, 4, 0), > ARM64_FTR_BITS(FTR_STRICT, FTR_EXACT, ID_AA64DFR0_DEBUGVER_SHIFT, 4, > 0x6), > ARM64_FTR_END, > -- > 2.1.4 >
