On Wed, May 22, 2019 at 04:30:17PM +0100, 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@xxxxxxx>
> Reviewed-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
> ---
> 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);
Acked-by: Will Deacon <will.deacon@xxxxxxx>
Although if the definition of armv8pmu_evtype_is_chain() isn't going to
get any more complicated than a single evtype comparison, I'm not sure it's
worth this abstraction, to be honest.
Will
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