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Groups > linux.kernel > #1550617
| From | Mark Rutland <mark.rutland@arm.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [RFC PATCH 01/10] arm64: cpufeature: allow for version discrepancy in PMU implementations |
| Date | 2017-01-04 11:30 +0100 |
| Message-ID | <sVQZr-3pc-3@gated-at.bofh.it> (permalink) |
| References | <sVBQJ-1Kc-7@gated-at.bofh.it> <sVBQJ-1Kc-23@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
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 <suzuki.poulose@arm.com>
> Signed-off-by: Will Deacon <will.deacon@arm.com>
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 <mark.rutland@arm.com>
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
>
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[RFC PATCH 00/10] Add support for the ARMv8.2 Statistical Profiling Extension Will Deacon <will.deacon@arm.com> - 2017-01-03 19:20 +0100
[RFC PATCH 02/10] arm64: cpufeature: Don't enforce system-wide SPE capability Will Deacon <will.deacon@arm.com> - 2017-01-03 19:20 +0100
Re: [RFC PATCH 02/10] arm64: cpufeature: Don't enforce system-wide SPE capability Mark Rutland <mark.rutland@arm.com> - 2017-01-04 12:10 +0100
[RFC PATCH 05/10] genirq: export irq_get_percpu_devid_partition to modules Will Deacon <will.deacon@arm.com> - 2017-01-03 19:20 +0100
[RFC PATCH 01/10] arm64: cpufeature: allow for version discrepancy in PMU implementations Will Deacon <will.deacon@arm.com> - 2017-01-03 19:20 +0100
Re: [RFC PATCH 01/10] arm64: cpufeature: allow for version discrepancy in PMU implementations Mark Rutland <mark.rutland@arm.com> - 2017-01-04 11:30 +0100
[RFC PATCH 04/10] arm64: head.S: Enable EL1 (host) access to SPE when entered at EL2 Will Deacon <will.deacon@arm.com> - 2017-01-03 19:20 +0100
[RFC PATCH 09/10] drivers/perf: Add support for ARMv8.2 Statistical Profiling Extension Will Deacon <will.deacon@arm.com> - 2017-01-03 19:20 +0100
Re: [RFC PATCH 09/10] drivers/perf: Add support for ARMv8.2 Statistical Profiling Extension Peter Zijlstra <peterz@infradead.org> - 2017-01-04 11:40 +0100
Re: [RFC PATCH 09/10] drivers/perf: Add support for ARMv8.2 Statistical Profiling Extension Will Deacon <will.deacon@arm.com> - 2017-01-04 20:20 +0100
Re: [RFC PATCH 09/10] drivers/perf: Add support for ARMv8.2 Statistical Profiling Extension Peter Zijlstra <peterz@infradead.org> - 2017-01-05 12:40 +0100
Re: [RFC PATCH 09/10] drivers/perf: Add support for ARMv8.2 Statistical Profiling Extension Kim Phillips <kim.phillips@arm.com> - 2017-01-10 23:10 +0100
Re: [RFC PATCH 09/10] drivers/perf: Add support for ARMv8.2 Statistical Profiling Extension Will Deacon <will.deacon@arm.com> - 2017-01-11 13:40 +0100
Re: [RFC PATCH 09/10] drivers/perf: Add support for ARMv8.2 Statistical Profiling Extension Kim Phillips <kim.phillips@arm.com> - 2017-01-11 22:10 +0100
Re: [RFC PATCH 09/10] drivers/perf: Add support for ARMv8.2 Statistical Profiling Extension Will Deacon <will.deacon@arm.com> - 2017-01-13 14:40 +0100
Re: [RFC PATCH 09/10] drivers/perf: Add support for ARMv8.2 Statistical Profiling Extension Marc Zyngier <marc.zyngier@arm.com> - 2017-01-12 12:40 +0100
[RFC PATCH 07/10] perf: Directly pass PERF_AUX_* flags to perf_aux_output_end Will Deacon <will.deacon@arm.com> - 2017-01-03 19:20 +0100
[RFC PATCH 03/10] arm64: KVM: Save/restore the host SPE state when entering/leaving a VM Will Deacon <will.deacon@arm.com> - 2017-01-03 19:20 +0100
[RFC PATCH 10/10] dt-bindings: Document devicetree binding for ARM SPE Will Deacon <will.deacon@arm.com> - 2017-01-03 19:20 +0100
[RFC PATCH 08/10] perf/core: Add PERF_AUX_FLAG_COLLISION to report colliding samples Will Deacon <will.deacon@arm.com> - 2017-01-03 19:20 +0100
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