[PATCH V6 3/7] arm64/perf: Add branch stack support in struct arm_pmu

[Anshuman Khandual]

This updates 'struct arm_pmu' for branch stack sampling support later. This
adds a new 'features' element in the structure to track supported features,
and another 'hw_attr' element to encapsulate implementation attributes on a
given 'struct arm_pmu'. These updates here will help in tracking any branch
stack sampling support, which is being added later. This also adds a helper
arm_pmu_branch_stack_supported().

Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Cc: Mark Rutland <mark.rutland@xxxxxxx>
Cc: linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
Signed-off-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
---
 include/linux/perf/arm_pmu.h | 9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/include/linux/perf/arm_pmu.h b/include/linux/perf/arm_pmu.h
index 60d4e4c9b3ea..8c4f42189904 100644
--- a/include/linux/perf/arm_pmu.h
+++ b/include/linux/perf/arm_pmu.h
@@ -80,11 +80,14 @@ enum armpmu_attr_groups {
 	ARMPMU_NR_ATTR_GROUPS
 };
 
+#define ARM_PMU_BRANCH_STACK	BIT(0)
+
 struct arm_pmu {
 	struct pmu	pmu;
 	cpumask_t	supported_cpus;
 	char		*name;
 	int		pmuver;
+	int		features;
 	irqreturn_t	(*handle_irq)(struct arm_pmu *pmu);
 	void		(*enable)(struct perf_event *event);
 	void		(*disable)(struct perf_event *event);
@@ -119,8 +122,14 @@ struct arm_pmu {
 
 	/* Only to be used by ACPI probing code */
 	unsigned long acpi_cpuid;
+	void		*hw_attr;
 };
 
+static inline bool arm_pmu_branch_stack_supported(struct arm_pmu *armpmu)
+{
+	return armpmu->features & ARM_PMU_BRANCH_STACK;
+}
+
 #define to_arm_pmu(p) (container_of(p, struct arm_pmu, pmu))
 
 u64 armpmu_event_update(struct perf_event *event);
-- 
2.25.1