2022-11-28 03:27:40

by Anshuman Khandual

Subject: [PATCH] arm64/perf: Replace PMU version number '0' with ID_AA64DFR0_EL1_PMUVer_NI

__armv8pmu_probe_pmu() returns if detected PMU is either not implemented or
implementation defined. Extracted ID_AA64DFR0_EL1_PMUVer value, when PMU is
not implemented is '0' which can be replaced with ID_AA64DFR0_EL1_PMUVer_NI
defined as '0b0000'.

Cc: Arnaldo Carvalho de Melo <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Catalin Marinas <[email protected]>
Cc: [email protected]
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Anshuman Khandual <[email protected]>
---
This applies on v6.1-rc6

arch/arm64/kernel/perf_event.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c
index 85a3aaefc0fb..b638f584b4dd 100644
--- a/arch/arm64/kernel/perf_event.c
+++ b/arch/arm64/kernel/perf_event.c
@@ -1188,7 +1188,8 @@ static void __armv8pmu_probe_pmu(void *info)
dfr0 = read_sysreg(id_aa64dfr0_el1);
pmuver = cpuid_feature_extract_unsigned_field(dfr0,
ID_AA64DFR0_EL1_PMUVer_SHIFT);
- if (pmuver == ID_AA64DFR0_EL1_PMUVer_IMP_DEF || pmuver == 0)
+ if (pmuver == ID_AA64DFR0_EL1_PMUVer_IMP_DEF ||
+ pmuver == ID_AA64DFR0_EL1_PMUVer_NI)
return;

cpu_pmu->pmuver = pmuver;
--
2.25.1

2022-11-28 04:17:54

by Anshuman Khandual

Subject: Re: [PATCH] arm64/perf: Replace PMU version number '0' with ID_AA64DFR0_EL1_PMUVer_NI

On 11/28/22 08:24, Anshuman Khandual wrote:
> __armv8pmu_probe_pmu() returns if detected PMU is either not implemented or
> implementation defined. Extracted ID_AA64DFR0_EL1_PMUVer value, when PMU is
> not implemented is '0' which can be replaced with ID_AA64DFR0_EL1_PMUVer_NI
> defined as '0b0000'.
>
> Cc: Arnaldo Carvalho de Melo <[email protected]>
> Cc: Mark Rutland <[email protected]>
> Cc: Will Deacon <[email protected]>
> Cc: Catalin Marinas <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Signed-off-by: Anshuman Khandual <[email protected]>
> ---
> This applies on v6.1-rc6
>
> arch/arm64/kernel/perf_event.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c
> index 85a3aaefc0fb..b638f584b4dd 100644
> --- a/arch/arm64/kernel/perf_event.c
> +++ b/arch/arm64/kernel/perf_event.c
> @@ -1188,7 +1188,8 @@ static void __armv8pmu_probe_pmu(void *info)
> dfr0 = read_sysreg(id_aa64dfr0_el1);
> pmuver = cpuid_feature_extract_unsigned_field(dfr0,
> ID_AA64DFR0_EL1_PMUVer_SHIFT);
> - if (pmuver == ID_AA64DFR0_EL1_PMUVer_IMP_DEF || pmuver == 0)
> + if (pmuver == ID_AA64DFR0_EL1_PMUVer_IMP_DEF ||
> + pmuver == ID_AA64DFR0_EL1_PMUVer_NI)
> return;
>
> cpu_pmu->pmuver = pmuver;
> --

+ Marc Zyngier <[email protected]>

There are some KVM related pmuver not-implemented check as well, should they be
replaced in this patch or rather in a separate patch ?

arch/arm64/kvm/pmu-emul.c: if (pmu->pmuver == 0 || pmu->pmuver == ID_AA64DFR0_EL1_PMUVer_IMP_DEF)
arch/arm64/kvm/pmu-emul.c: if (pmu->pmuver == 0 ||
arch/arm64/kvm/pmu-emul.c: pmu->pmuver == ID_AA64DFR0_EL1_PMUVer_IMP_DEF)

- Anshuman

2022-11-28 09:06:40

by Marc Zyngier

Subject: Re: [PATCH] arm64/perf: Replace PMU version number '0' with ID_AA64DFR0_EL1_PMUVer_NI

On Mon, 28 Nov 2022 03:06:15 +0000,
Anshuman Khandual <[email protected]> wrote:
>
>
>
> On 11/28/22 08:24, Anshuman Khandual wrote:
> > __armv8pmu_probe_pmu() returns if detected PMU is either not implemented or
> > implementation defined. Extracted ID_AA64DFR0_EL1_PMUVer value, when PMU is
> > not implemented is '0' which can be replaced with ID_AA64DFR0_EL1_PMUVer_NI
> > defined as '0b0000'.
> >
> > Cc: Arnaldo Carvalho de Melo <[email protected]>
> > Cc: Mark Rutland <[email protected]>
> > Cc: Will Deacon <[email protected]>
> > Cc: Catalin Marinas <[email protected]>
> > Cc: [email protected]
> > Cc: [email protected]
> > Cc: [email protected]
> > Signed-off-by: Anshuman Khandual <[email protected]>
> > ---
> > This applies on v6.1-rc6
> >
> > arch/arm64/kernel/perf_event.c | 3 ++-
> > 1 file changed, 2 insertions(+), 1 deletion(-)
> >
> > diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c
> > index 85a3aaefc0fb..b638f584b4dd 100644
> > --- a/arch/arm64/kernel/perf_event.c
> > +++ b/arch/arm64/kernel/perf_event.c
> > @@ -1188,7 +1188,8 @@ static void __armv8pmu_probe_pmu(void *info)
> > dfr0 = read_sysreg(id_aa64dfr0_el1);
> > pmuver = cpuid_feature_extract_unsigned_field(dfr0,
> > ID_AA64DFR0_EL1_PMUVer_SHIFT);
> > - if (pmuver == ID_AA64DFR0_EL1_PMUVer_IMP_DEF || pmuver == 0)
> > + if (pmuver == ID_AA64DFR0_EL1_PMUVer_IMP_DEF ||
> > + pmuver == ID_AA64DFR0_EL1_PMUVer_NI)
> > return;
> >
> > cpu_pmu->pmuver = pmuver;
> > --
>
> + Marc Zyngier <[email protected]>
>
> There are some KVM related pmuver not-implemented check as well, should they be
> replaced in this patch or rather in a separate patch ?
>
> arch/arm64/kvm/pmu-emul.c: if (pmu->pmuver == 0 || pmu->pmuver == ID_AA64DFR0_EL1_PMUVer_IMP_DEF)
> arch/arm64/kvm/pmu-emul.c: if (pmu->pmuver == 0 ||
> arch/arm64/kvm/pmu-emul.c: pmu->pmuver == ID_AA64DFR0_EL1_PMUVer_IMP_DEF)

Separate patch please, as I have a large KVM PMU rework already
queued.

Thanks,

M.

--
Without deviation from the norm, progress is not possible.

2022-11-28 12:42:14

by Mark Rutland

Subject: Re: [PATCH] arm64/perf: Replace PMU version number '0' with ID_AA64DFR0_EL1_PMUVer_NI

On Mon, Nov 28, 2022 at 08:24:49AM +0530, Anshuman Khandual wrote:
> __armv8pmu_probe_pmu() returns if detected PMU is either not implemented or
> implementation defined. Extracted ID_AA64DFR0_EL1_PMUVer value, when PMU is
> not implemented is '0' which can be replaced with ID_AA64DFR0_EL1_PMUVer_NI
> defined as '0b0000'.
>
> Cc: Arnaldo Carvalho de Melo <[email protected]>
> Cc: Mark Rutland <[email protected]>
> Cc: Will Deacon <[email protected]>
> Cc: Catalin Marinas <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> Cc: [email protected]
> Signed-off-by: Anshuman Khandual <[email protected]>

This looks fine to me, so:

Acked-by: Mark Rutland <[email protected]>

I'll leave it to Will to pick this as his convenience.

Mark.

> ---
> This applies on v6.1-rc6
>
> arch/arm64/kernel/perf_event.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c
> index 85a3aaefc0fb..b638f584b4dd 100644
> --- a/arch/arm64/kernel/perf_event.c
> +++ b/arch/arm64/kernel/perf_event.c
> @@ -1188,7 +1188,8 @@ static void __armv8pmu_probe_pmu(void *info)
> dfr0 = read_sysreg(id_aa64dfr0_el1);
> pmuver = cpuid_feature_extract_unsigned_field(dfr0,
> ID_AA64DFR0_EL1_PMUVer_SHIFT);
> - if (pmuver == ID_AA64DFR0_EL1_PMUVer_IMP_DEF || pmuver == 0)
> + if (pmuver == ID_AA64DFR0_EL1_PMUVer_IMP_DEF ||
> + pmuver == ID_AA64DFR0_EL1_PMUVer_NI)
> return;
>
> cpu_pmu->pmuver = pmuver;
> --
> 2.25.1
>

2022-11-29 20:19:12

by Will Deacon

Subject: Re: [PATCH] arm64/perf: Replace PMU version number '0' with ID_AA64DFR0_EL1_PMUVer_NI

On Mon, 28 Nov 2022 08:24:49 +0530, Anshuman Khandual wrote:
> __armv8pmu_probe_pmu() returns if detected PMU is either not implemented or
> implementation defined. Extracted ID_AA64DFR0_EL1_PMUVer value, when PMU is
> not implemented is '0' which can be replaced with ID_AA64DFR0_EL1_PMUVer_NI
> defined as '0b0000'.
>
>

Applied to will (for-next/perf), thanks!

[1/1] arm64/perf: Replace PMU version number '0' with ID_AA64DFR0_EL1_PMUVer_NI
https://git.kernel.org/will/c/cc91b9481605

Cheers,
--
Will

https://fixes.arm64.dev
https://next.arm64.dev
https://will.arm64.dev