[PATCH 0/5] perf: oprofile spring cleanup

[PATCH 0/5] perf: oprofile spring cleanup

[Marc Zyngier]

This small series builds on top of the work that was started with [1].

It recently became apparent that KVM/arm64 is the last bit of the
kernel that still uses perf_num_counters().

As I went ahead to address this, it became obvious that all traces of
oprofile had been eradicated from all architectures but arm64, s390
and sh (plus a bit of cruft in the core perf code). With KVM fixed,
perf_num_counters() and perf_pmu_name() are finally gone.

Thanks,

	M.

[1] https://lore.kernel.org/lkml/20210215050618.hgftdmfmslbdrg3j@vireshk-i7

Marc Zyngier (5):
  KVM: arm64: Divorce the perf code from oprofile helpers
  arm64: Get rid of oprofile leftovers
  s390: Get rid of oprofile leftovers
  sh: Get rid of oprofile leftovers
  perf: Get rid of oprofile leftovers

 arch/arm64/kvm/perf.c         |  7 +------
 arch/arm64/kvm/pmu-emul.c     |  2 +-
 arch/s390/kernel/perf_event.c | 21 ---------------------
 arch/sh/kernel/perf_event.c   | 18 ------------------
 drivers/perf/arm_pmu.c        | 30 ------------------------------
 include/kvm/arm_pmu.h         |  4 ++++
 include/linux/perf_event.h    |  2 --
 kernel/events/core.c          |  5 -----
 8 files changed, 6 insertions(+), 83 deletions(-)

-- 
2.29.2
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[PATCH 1/5] KVM: arm64: Divorce the perf code from oprofile helpers

[Marc Zyngier]

KVM/arm64 is the sole user of perf_num_counters(), and really
could do without it. Stop using the obsolete API by relying on
the existing probing code.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kvm/perf.c     | 7 +------
 arch/arm64/kvm/pmu-emul.c | 2 +-
 include/kvm/arm_pmu.h     | 4 ++++
 3 files changed, 6 insertions(+), 7 deletions(-)

diff --git a/arch/arm64/kvm/perf.c b/arch/arm64/kvm/perf.c
index 739164324afe..b8b398670ef2 100644
--- a/arch/arm64/kvm/perf.c
+++ b/arch/arm64/kvm/perf.c
@@ -50,12 +50,7 @@ static struct perf_guest_info_callbacks kvm_guest_cbs = {
 
 int kvm_perf_init(void)
 {
-	/*
-	 * Check if HW_PERF_EVENTS are supported by checking the number of
-	 * hardware performance counters. This could ensure the presence of
-	 * a physical PMU and CONFIG_PERF_EVENT is selected.
-	 */
-	if (IS_ENABLED(CONFIG_ARM_PMU) && perf_num_counters() > 0)
+	if (kvm_pmu_probe_pmuver() != 0xf)
 		static_branch_enable(&kvm_arm_pmu_available);
 
 	return perf_register_guest_info_callbacks(&kvm_guest_cbs);
diff --git a/arch/arm64/kvm/pmu-emul.c b/arch/arm64/kvm/pmu-emul.c
index e32c6e139a09..fd167d4f4215 100644
--- a/arch/arm64/kvm/pmu-emul.c
+++ b/arch/arm64/kvm/pmu-emul.c
@@ -739,7 +739,7 @@ void kvm_pmu_set_counter_event_type(struct kvm_vcpu *vcpu, u64 data,
 	kvm_pmu_create_perf_event(vcpu, select_idx);
 }
 
-static int kvm_pmu_probe_pmuver(void)
+int kvm_pmu_probe_pmuver(void)
 {
 	struct perf_event_attr attr = { };
 	struct perf_event *event;
diff --git a/include/kvm/arm_pmu.h b/include/kvm/arm_pmu.h
index 6fd3cda608e4..864b9997efb2 100644
--- a/include/kvm/arm_pmu.h
+++ b/include/kvm/arm_pmu.h
@@ -61,6 +61,7 @@ int kvm_arm_pmu_v3_get_attr(struct kvm_vcpu *vcpu,
 int kvm_arm_pmu_v3_has_attr(struct kvm_vcpu *vcpu,
 			    struct kvm_device_attr *attr);
 int kvm_arm_pmu_v3_enable(struct kvm_vcpu *vcpu);
+int kvm_pmu_probe_pmuver(void);
 #else
 struct kvm_pmu {
 };
@@ -116,6 +117,9 @@ static inline u64 kvm_pmu_get_pmceid(struct kvm_vcpu *vcpu, bool pmceid1)
 {
 	return 0;
 }
+
+static inline int kvm_pmu_probe_pmuver(void) { return 0xf; }
+
 #endif
 
 #endif
-- 
2.29.2

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[PATCH 2/5] arm64: Get rid of oprofile leftovers

[Marc Zyngier]

perf_pmu_name() and perf_num_counters() are now unused. Drop them.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 drivers/perf/arm_pmu.c | 30 ------------------------------
 1 file changed, 30 deletions(-)

diff --git a/drivers/perf/arm_pmu.c b/drivers/perf/arm_pmu.c
index 2d10d84fb79c..d4f7f1f9cc77 100644
--- a/drivers/perf/arm_pmu.c
+++ b/drivers/perf/arm_pmu.c
@@ -581,33 +581,6 @@ static const struct attribute_group armpmu_common_attr_group = {
 	.attrs = armpmu_common_attrs,
 };
 
-/* Set at runtime when we know what CPU type we are. */
-static struct arm_pmu *__oprofile_cpu_pmu;
-
-/*
- * Despite the names, these two functions are CPU-specific and are used
- * by the OProfile/perf code.
- */
-const char *perf_pmu_name(void)
-{
-	if (!__oprofile_cpu_pmu)
-		return NULL;
-
-	return __oprofile_cpu_pmu->name;
-}
-EXPORT_SYMBOL_GPL(perf_pmu_name);
-
-int perf_num_counters(void)
-{
-	int max_events = 0;
-
-	if (__oprofile_cpu_pmu != NULL)
-		max_events = __oprofile_cpu_pmu->num_events;
-
-	return max_events;
-}
-EXPORT_SYMBOL_GPL(perf_num_counters);
-
 static int armpmu_count_irq_users(const int irq)
 {
 	int cpu, count = 0;
@@ -979,9 +952,6 @@ int armpmu_register(struct arm_pmu *pmu)
 	if (ret)
 		goto out_destroy;
 
-	if (!__oprofile_cpu_pmu)
-		__oprofile_cpu_pmu = pmu;
-
 	pr_info("enabled with %s PMU driver, %d counters available%s\n",
 		pmu->name, pmu->num_events,
 		has_nmi ? ", using NMIs" : "");
-- 
2.29.2

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[PATCH 3/5] s390: Get rid of oprofile leftovers

[Marc Zyngier]

perf_pmu_name() and perf_num_counters() are unused. Drop them.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/s390/kernel/perf_event.c | 21 ---------------------
 1 file changed, 21 deletions(-)

diff --git a/arch/s390/kernel/perf_event.c b/arch/s390/kernel/perf_event.c
index 1e75cc983546..ea7729bebaa0 100644
--- a/arch/s390/kernel/perf_event.c
+++ b/arch/s390/kernel/perf_event.c
@@ -23,27 +23,6 @@
 #include <asm/sysinfo.h>
 #include <asm/unwind.h>
 
-const char *perf_pmu_name(void)
-{
-	if (cpum_cf_avail() || cpum_sf_avail())
-		return "CPU-Measurement Facilities (CPU-MF)";
-	return "pmu";
-}
-EXPORT_SYMBOL(perf_pmu_name);
-
-int perf_num_counters(void)
-{
-	int num = 0;
-
-	if (cpum_cf_avail())
-		num += PERF_CPUM_CF_MAX_CTR;
-	if (cpum_sf_avail())
-		num += PERF_CPUM_SF_MAX_CTR;
-
-	return num;
-}
-EXPORT_SYMBOL(perf_num_counters);
-
 static struct kvm_s390_sie_block *sie_block(struct pt_regs *regs)
 {
 	struct stack_frame *stack = (struct stack_frame *) regs->gprs[15];
-- 
2.29.2

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[PATCH 4/5] sh: Get rid of oprofile leftovers

[Marc Zyngier]

perf_pmu_name() and perf_num_counters() are unused. Drop them.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/sh/kernel/perf_event.c | 18 ------------------
 1 file changed, 18 deletions(-)

diff --git a/arch/sh/kernel/perf_event.c b/arch/sh/kernel/perf_event.c
index 445e3ece4c23..1d2507f22437 100644
--- a/arch/sh/kernel/perf_event.c
+++ b/arch/sh/kernel/perf_event.c
@@ -57,24 +57,6 @@ static inline int sh_pmu_initialized(void)
 	return !!sh_pmu;
 }
 
-const char *perf_pmu_name(void)
-{
-	if (!sh_pmu)
-		return NULL;
-
-	return sh_pmu->name;
-}
-EXPORT_SYMBOL_GPL(perf_pmu_name);
-
-int perf_num_counters(void)
-{
-	if (!sh_pmu)
-		return 0;
-
-	return sh_pmu->num_events;
-}
-EXPORT_SYMBOL_GPL(perf_num_counters);
-
 /*
  * Release the PMU if this is the last perf_event.
  */
-- 
2.29.2

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[PATCH 5/5] perf: Get rid of oprofile leftovers

[Marc Zyngier]

perf_pmu_name() and perf_num_counters() are unused. Drop them.

Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 include/linux/perf_event.h | 2 --
 kernel/events/core.c       | 5 -----
 2 files changed, 7 deletions(-)

diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
index 3f7f89ea5e51..51154ed9a206 100644
--- a/include/linux/perf_event.h
+++ b/include/linux/perf_event.h
@@ -951,8 +951,6 @@ extern void perf_event_itrace_started(struct perf_event *event);
 extern int perf_pmu_register(struct pmu *pmu, const char *name, int type);
 extern void perf_pmu_unregister(struct pmu *pmu);
 
-extern int perf_num_counters(void);
-extern const char *perf_pmu_name(void);
 extern void __perf_event_task_sched_in(struct task_struct *prev,
 				       struct task_struct *task);
 extern void __perf_event_task_sched_out(struct task_struct *prev,
diff --git a/kernel/events/core.c b/kernel/events/core.c
index 03db40f6cba9..88cb0ba5690b 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -580,11 +580,6 @@ static u64 perf_event_time(struct perf_event *event);
 
 void __weak perf_event_print_debug(void)	{ }
 
-extern __weak const char *perf_pmu_name(void)
-{
-	return "pmu";
-}
-
 static inline u64 perf_clock(void)
 {
 	return local_clock();
-- 
2.29.2

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Re: [PATCH 4/5] sh: Get rid of oprofile leftovers

[Geert Uytterhoeven]

On Wed, Apr 14, 2021 at 3:53 PM Marc Zyngier <maz@kernel.org> wrote:
> perf_pmu_name() and perf_num_counters() are unused. Drop them.
>
> Signed-off-by: Marc Zyngier <maz@kernel.org>

Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>

Gr{oetje,eeting}s,

                        Geert

-- 
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
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Re: [PATCH 1/5] KVM: arm64: Divorce the perf code from oprofile helpers

[Keqian Zhu]

Hi Marc,

On 2021/4/14 21:44, Marc Zyngier wrote:
> KVM/arm64 is the sole user of perf_num_counters(), and really
> could do without it. Stop using the obsolete API by relying on
> the existing probing code.
> 
> Signed-off-by: Marc Zyngier <maz@kernel.org>
> ---
>  arch/arm64/kvm/perf.c     | 7 +------
>  arch/arm64/kvm/pmu-emul.c | 2 +-
>  include/kvm/arm_pmu.h     | 4 ++++
>  3 files changed, 6 insertions(+), 7 deletions(-)
> 
> diff --git a/arch/arm64/kvm/perf.c b/arch/arm64/kvm/perf.c
> index 739164324afe..b8b398670ef2 100644
> --- a/arch/arm64/kvm/perf.c
> +++ b/arch/arm64/kvm/perf.c
> @@ -50,12 +50,7 @@ static struct perf_guest_info_callbacks kvm_guest_cbs = {
>  
>  int kvm_perf_init(void)
>  {
> -	/*
> -	 * Check if HW_PERF_EVENTS are supported by checking the number of
> -	 * hardware performance counters. This could ensure the presence of
> -	 * a physical PMU and CONFIG_PERF_EVENT is selected.
> -	 */
> -	if (IS_ENABLED(CONFIG_ARM_PMU) && perf_num_counters() > 0)
> +	if (kvm_pmu_probe_pmuver() != 0xf)
The probe() function may be called many times (kvm_arm_pmu_v3_set_attr also calls it).
I don't know whether the first calling is enough. If so, can we use a static variable
in it, so the following calling can return the result right away?

Thanks,
Keqian
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Re: [PATCH 3/5] s390: Get rid of oprofile leftovers

[Heiko Carstens]

On Wed, Apr 14, 2021 at 02:44:07PM +0100, Marc Zyngier wrote:
> perf_pmu_name() and perf_num_counters() are unused. Drop them.
> 
> Signed-off-by: Marc Zyngier <maz@kernel.org>
> ---
>  arch/s390/kernel/perf_event.c | 21 ---------------------
>  1 file changed, 21 deletions(-)

Acked-by: Heiko Carstens <hca@linux.ibm.com>

...or do you want me to pick this up and route via the s390 tree(?).
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Re: [PATCH 1/5] KVM: arm64: Divorce the perf code from oprofile helpers

[Marc Zyngier]

On Thu, 15 Apr 2021 07:59:26 +0100,
Keqian Zhu <zhukeqian1@huawei.com> wrote:
> 
> Hi Marc,
> 
> On 2021/4/14 21:44, Marc Zyngier wrote:
> > KVM/arm64 is the sole user of perf_num_counters(), and really
> > could do without it. Stop using the obsolete API by relying on
> > the existing probing code.
> > 
> > Signed-off-by: Marc Zyngier <maz@kernel.org>
> > ---
> >  arch/arm64/kvm/perf.c     | 7 +------
> >  arch/arm64/kvm/pmu-emul.c | 2 +-
> >  include/kvm/arm_pmu.h     | 4 ++++
> >  3 files changed, 6 insertions(+), 7 deletions(-)
> > 
> > diff --git a/arch/arm64/kvm/perf.c b/arch/arm64/kvm/perf.c
> > index 739164324afe..b8b398670ef2 100644
> > --- a/arch/arm64/kvm/perf.c
> > +++ b/arch/arm64/kvm/perf.c
> > @@ -50,12 +50,7 @@ static struct perf_guest_info_callbacks kvm_guest_cbs = {
> >  
> >  int kvm_perf_init(void)
> >  {
> > -	/*
> > -	 * Check if HW_PERF_EVENTS are supported by checking the number of
> > -	 * hardware performance counters. This could ensure the presence of
> > -	 * a physical PMU and CONFIG_PERF_EVENT is selected.
> > -	 */
> > -	if (IS_ENABLED(CONFIG_ARM_PMU) && perf_num_counters() > 0)
> > +	if (kvm_pmu_probe_pmuver() != 0xf)
> The probe() function may be called many times
> (kvm_arm_pmu_v3_set_attr also calls it).  I don't know whether the
> first calling is enough. If so, can we use a static variable in it,
> so the following calling can return the result right away?

No, because that wouldn't help with crappy big-little implementations
that could have PMUs with different versions. We want to find the
version at the point where the virtual PMU is created, which is why we
call the probe function once per vcpu.

This of course is broken in other ways (BL+KVM is a total disaster
when it comes to PMU), but making this static would just make it
worse.

	M.

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Re: [PATCH 3/5] s390: Get rid of oprofile leftovers

[Marc Zyngier]

On Thu, 15 Apr 2021 11:38:52 +0100,
Heiko Carstens <hca@linux.ibm.com> wrote:
> 
> On Wed, Apr 14, 2021 at 02:44:07PM +0100, Marc Zyngier wrote:
> > perf_pmu_name() and perf_num_counters() are unused. Drop them.
> > 
> > Signed-off-by: Marc Zyngier <maz@kernel.org>
> > ---
> >  arch/s390/kernel/perf_event.c | 21 ---------------------
> >  1 file changed, 21 deletions(-)
> 
> Acked-by: Heiko Carstens <hca@linux.ibm.com>
> 
> ...or do you want me to pick this up and route via the s390 tree(?).

Either way work for me, but I just want to make sure the last patch
doesn't get applied before the previous ones.

Thanks,

	M.

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Re: [PATCH 1/5] KVM: arm64: Divorce the perf code from oprofile helpers

[Keqian Zhu]

Hi Marc,

On 2021/4/15 18:42, Marc Zyngier wrote:
> On Thu, 15 Apr 2021 07:59:26 +0100,
> Keqian Zhu <zhukeqian1@huawei.com> wrote:
>>
>> Hi Marc,
>>
>> On 2021/4/14 21:44, Marc Zyngier wrote:
>>> KVM/arm64 is the sole user of perf_num_counters(), and really
>>> could do without it. Stop using the obsolete API by relying on
>>> the existing probing code.
>>>
>>> Signed-off-by: Marc Zyngier <maz@kernel.org>
>>> ---
>>>  arch/arm64/kvm/perf.c     | 7 +------
>>>  arch/arm64/kvm/pmu-emul.c | 2 +-
>>>  include/kvm/arm_pmu.h     | 4 ++++
>>>  3 files changed, 6 insertions(+), 7 deletions(-)
>>>
>>> diff --git a/arch/arm64/kvm/perf.c b/arch/arm64/kvm/perf.c
>>> index 739164324afe..b8b398670ef2 100644
>>> --- a/arch/arm64/kvm/perf.c
>>> +++ b/arch/arm64/kvm/perf.c
>>> @@ -50,12 +50,7 @@ static struct perf_guest_info_callbacks kvm_guest_cbs = {
>>>  
>>>  int kvm_perf_init(void)
>>>  {
>>> -	/*
>>> -	 * Check if HW_PERF_EVENTS are supported by checking the number of
>>> -	 * hardware performance counters. This could ensure the presence of
>>> -	 * a physical PMU and CONFIG_PERF_EVENT is selected.
>>> -	 */
>>> -	if (IS_ENABLED(CONFIG_ARM_PMU) && perf_num_counters() > 0)
>>> +	if (kvm_pmu_probe_pmuver() != 0xf)
>> The probe() function may be called many times
>> (kvm_arm_pmu_v3_set_attr also calls it).  I don't know whether the
>> first calling is enough. If so, can we use a static variable in it,
>> so the following calling can return the result right away?
> 
> No, because that wouldn't help with crappy big-little implementations
> that could have PMUs with different versions. We want to find the
> version at the point where the virtual PMU is created, which is why we
> call the probe function once per vcpu.
I see.

But AFAICS the pmuver is placed in kvm->arch, and the probe function is called
once per VM. Maybe I miss something.

> 
> This of course is broken in other ways (BL+KVM is a total disaster
> when it comes to PMU), but making this static would just make it
> worse.
OK.

Thanks,
Keqian
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Re: [PATCH 3/5] s390: Get rid of oprofile leftovers

[Heiko Carstens]

On Thu, Apr 15, 2021 at 11:47:26AM +0100, Marc Zyngier wrote:
> On Thu, 15 Apr 2021 11:38:52 +0100,
> Heiko Carstens <hca@linux.ibm.com> wrote:
> > 
> > On Wed, Apr 14, 2021 at 02:44:07PM +0100, Marc Zyngier wrote:
> > > perf_pmu_name() and perf_num_counters() are unused. Drop them.
> > > 
> > > Signed-off-by: Marc Zyngier <maz@kernel.org>
> > > ---
> > >  arch/s390/kernel/perf_event.c | 21 ---------------------
> > >  1 file changed, 21 deletions(-)
> > 
> > Acked-by: Heiko Carstens <hca@linux.ibm.com>
> > 
> > ...or do you want me to pick this up and route via the s390 tree(?).
> 
> Either way work for me, but I just want to make sure the last patch
> doesn't get applied before the previous ones.

Ok, I applied this one to the s390 tree. Thanks!
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Re: [PATCH 1/5] KVM: arm64: Divorce the perf code from oprofile helpers

[Marc Zyngier]

On Thu, 15 Apr 2021 12:34:40 +0100,
Keqian Zhu <zhukeqian1@huawei.com> wrote:
> 
> Hi Marc,
> 
> On 2021/4/15 18:42, Marc Zyngier wrote:
> > On Thu, 15 Apr 2021 07:59:26 +0100,
> > Keqian Zhu <zhukeqian1@huawei.com> wrote:
> >>
> >> Hi Marc,
> >>
> >> On 2021/4/14 21:44, Marc Zyngier wrote:
> >>> KVM/arm64 is the sole user of perf_num_counters(), and really
> >>> could do without it. Stop using the obsolete API by relying on
> >>> the existing probing code.
> >>>
> >>> Signed-off-by: Marc Zyngier <maz@kernel.org>
> >>> ---
> >>>  arch/arm64/kvm/perf.c     | 7 +------
> >>>  arch/arm64/kvm/pmu-emul.c | 2 +-
> >>>  include/kvm/arm_pmu.h     | 4 ++++
> >>>  3 files changed, 6 insertions(+), 7 deletions(-)
> >>>
> >>> diff --git a/arch/arm64/kvm/perf.c b/arch/arm64/kvm/perf.c
> >>> index 739164324afe..b8b398670ef2 100644
> >>> --- a/arch/arm64/kvm/perf.c
> >>> +++ b/arch/arm64/kvm/perf.c
> >>> @@ -50,12 +50,7 @@ static struct perf_guest_info_callbacks kvm_guest_cbs = {
> >>>  
> >>>  int kvm_perf_init(void)
> >>>  {
> >>> -	/*
> >>> -	 * Check if HW_PERF_EVENTS are supported by checking the number of
> >>> -	 * hardware performance counters. This could ensure the presence of
> >>> -	 * a physical PMU and CONFIG_PERF_EVENT is selected.
> >>> -	 */
> >>> -	if (IS_ENABLED(CONFIG_ARM_PMU) && perf_num_counters() > 0)
> >>> +	if (kvm_pmu_probe_pmuver() != 0xf)
> >> The probe() function may be called many times
> >> (kvm_arm_pmu_v3_set_attr also calls it).  I don't know whether the
> >> first calling is enough. If so, can we use a static variable in it,
> >> so the following calling can return the result right away?
> > 
> > No, because that wouldn't help with crappy big-little implementations
> > that could have PMUs with different versions. We want to find the
> > version at the point where the virtual PMU is created, which is why we
> > call the probe function once per vcpu.
> I see.
> 
> But AFAICS the pmuver is placed in kvm->arch, and the probe function is called
> once per VM. Maybe I miss something.

You're right, I mis-remembered. This doesn't change much though.

Thanks,

	M.

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Re: [PATCH 1/5] KVM: arm64: Divorce the perf code from oprofile helpers

[Will Deacon]

On Wed, Apr 14, 2021 at 02:44:05PM +0100, Marc Zyngier wrote:
> KVM/arm64 is the sole user of perf_num_counters(), and really
> could do without it. Stop using the obsolete API by relying on
> the existing probing code.
> 
> Signed-off-by: Marc Zyngier <maz@kernel.org>
> ---
>  arch/arm64/kvm/perf.c     | 7 +------
>  arch/arm64/kvm/pmu-emul.c | 2 +-
>  include/kvm/arm_pmu.h     | 4 ++++
>  3 files changed, 6 insertions(+), 7 deletions(-)
> 
> diff --git a/arch/arm64/kvm/perf.c b/arch/arm64/kvm/perf.c
> index 739164324afe..b8b398670ef2 100644
> --- a/arch/arm64/kvm/perf.c
> +++ b/arch/arm64/kvm/perf.c
> @@ -50,12 +50,7 @@ static struct perf_guest_info_callbacks kvm_guest_cbs = {
>  
>  int kvm_perf_init(void)
>  {
> -	/*
> -	 * Check if HW_PERF_EVENTS are supported by checking the number of
> -	 * hardware performance counters. This could ensure the presence of
> -	 * a physical PMU and CONFIG_PERF_EVENT is selected.
> -	 */
> -	if (IS_ENABLED(CONFIG_ARM_PMU) && perf_num_counters() > 0)
> +	if (kvm_pmu_probe_pmuver() != 0xf)

Took me a while to figure out that this returns 0xf if the hardware has a
PMUVer of 0x0, so it's all good:

Acked-by: Will Deacon <will@kernel.org>

Will
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Re: [PATCH 2/5] arm64: Get rid of oprofile leftovers

[Will Deacon]

On Wed, Apr 14, 2021 at 02:44:06PM +0100, Marc Zyngier wrote:
> perf_pmu_name() and perf_num_counters() are now unused. Drop them.
> 
> Signed-off-by: Marc Zyngier <maz@kernel.org>
> ---
>  drivers/perf/arm_pmu.c | 30 ------------------------------
>  1 file changed, 30 deletions(-)

Nice! This was some of the first code I ever wrote in the kernel but I can't
say I miss it:

Acked-by: Will Deacon <will@kernel.org>

Will
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Re: [PATCH 5/5] perf: Get rid of oprofile leftovers

[Will Deacon]

On Wed, Apr 14, 2021 at 02:44:09PM +0100, Marc Zyngier wrote:
> perf_pmu_name() and perf_num_counters() are unused. Drop them.
> 
> Signed-off-by: Marc Zyngier <maz@kernel.org>
> ---
>  include/linux/perf_event.h | 2 --
>  kernel/events/core.c       | 5 -----
>  2 files changed, 7 deletions(-)

Acked-by: Will Deacon <will@kernel.org>

Will
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Re: [PATCH 0/5] perf: oprofile spring cleanup

[Marc Zyngier]

On Wed, 14 Apr 2021 14:44:04 +0100, Marc Zyngier wrote:
> This small series builds on top of the work that was started with [1].
> 
> It recently became apparent that KVM/arm64 is the last bit of the
> kernel that still uses perf_num_counters().
> 
> As I went ahead to address this, it became obvious that all traces of
> oprofile had been eradicated from all architectures but arm64, s390
> and sh (plus a bit of cruft in the core perf code). With KVM fixed,
> perf_num_counters() and perf_pmu_name() are finally gone.
> 
> [...]

Applied to kvm-arm64/kill_oprofile_dependency, thanks!

[1/5] KVM: arm64: Divorce the perf code from oprofile helpers
      commit: 5421db1be3b11c5e469cce3760d5c8a013a90f2c
[2/5] arm64: Get rid of oprofile leftovers
      commit: e9c74a686a45e54b2e1c4586b14c84f3ee2f2014
[3/5] s390: Get rid of oprofile leftovers
      commit: 8c3f7913a106aa8b94d331cb59709c84a9a1d55b
[4/5] sh: Get rid of oprofile leftovers
      commit: ac21ecf5ad32b89909bee2b50161ce93d6462b7d
[5/5] perf: Get rid of oprofile leftovers
      commit: 7f318847a0f37b96d8927e8d30ae7b8f149b11f1

Cheers,

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


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