Re: [PATCH v7 4/5] arm64: perf: extract chain helper into header

[Suzuki K Poulose <suzuki.poulose@arm.com>]

On 21/05/2019 16:52, Andrew Murray wrote:
> The ARMv8 Performance Monitors Extension includes an architectural
> event type named CHAIN which allows for chaining counters together.
> 
> Let's extract the test for this event into a header file such that
> other users, such as KVM (for PMU emulation) can make use of.
> 
> Signed-off-by: Andrew Murray <andrew.murray@arm.com>
> ---
>   arch/arm64/include/asm/perf_event.h | 5 +++++
>   arch/arm64/kernel/perf_event.c      | 2 +-
>   2 files changed, 6 insertions(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/include/asm/perf_event.h b/arch/arm64/include/asm/perf_event.h
> index c593761ba61c..cd13f3fd1055 100644
> --- a/arch/arm64/include/asm/perf_event.h
> +++ b/arch/arm64/include/asm/perf_event.h
> @@ -219,6 +219,11 @@
>   #define ARMV8_PMU_USERENR_CR	(1 << 2) /* Cycle counter can be read at EL0 */
>   #define ARMV8_PMU_USERENR_ER	(1 << 3) /* Event counter can be read at EL0 */
>   
> +static inline bool armv8pmu_evtype_is_chain(u64 evtype)
> +{
> +	return (evtype == ARMV8_PMUV3_PERFCTR_CHAIN);
> +}
> +
>   #ifdef CONFIG_PERF_EVENTS
>   struct pt_regs;
>   extern unsigned long perf_instruction_pointer(struct pt_regs *regs);
> diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c
> index 314b1adedf06..265bd835a724 100644
> --- a/arch/arm64/kernel/perf_event.c
> +++ b/arch/arm64/kernel/perf_event.c
> @@ -879,7 +879,7 @@ static int armv8pmu_set_event_filter(struct hw_perf_event *event,
>   static int armv8pmu_filter_match(struct perf_event *event)
>   {
>   	unsigned long evtype = event->hw.config_base & ARMV8_PMU_EVTYPE_EVENT;
> -	return evtype != ARMV8_PMUV3_PERFCTR_CHAIN;
> +	return !armv8pmu_evtype_is_chain(evtype);
>   }
>   
>   static void armv8pmu_reset(void *info)
> 

Reviewed-by: Suzuki K Poulose <suzuki.poulose@arm.com>
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