[PATCH v1 1/2] perf/x86: Avoid inadvertent casts to x86_hybrid_pmu

[Ian Rogers]

The patch:
https://lore.kernel.org/lkml/20260311075201.2951073-2-dapeng1.mi@xxxxxxxxxxxxxxx/
showed it was pretty easy to accidentally cast non-x86 PMUs to
x86_hybrid_pmus. Add a BUG_ON for that case. Restructure is_x86_event
and add an is_x86_pmu to facilitate this.

Signed-off-by: Ian Rogers <irogers@xxxxxxxxxx>
---
Only build tested.
---
 arch/x86/events/core.c       | 16 ----------------
 arch/x86/events/perf_event.h | 19 ++++++++++++++++++-
 2 files changed, 18 insertions(+), 17 deletions(-)

diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c
index 03ce1bc7ef2e..6c6567dc6c88 100644
--- a/arch/x86/events/core.c
+++ b/arch/x86/events/core.c
@@ -774,22 +774,6 @@ void x86_pmu_enable_all(int added)
 	}
 }
 
-int is_x86_event(struct perf_event *event)
-{
-	/*
-	 * For a non-hybrid platforms, the type of X86 pmu is
-	 * always PERF_TYPE_RAW.
-	 * For a hybrid platform, the PERF_PMU_CAP_EXTENDED_HW_TYPE
-	 * is a unique capability for the X86 PMU.
-	 * Use them to detect a X86 event.
-	 */
-	if (event->pmu->type == PERF_TYPE_RAW ||
-	    event->pmu->capabilities & PERF_PMU_CAP_EXTENDED_HW_TYPE)
-		return true;
-
-	return false;
-}
-
 struct pmu *x86_get_pmu(unsigned int cpu)
 {
 	struct cpu_hw_events *cpuc = &per_cpu(cpu_hw_events, cpu);
diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h
index fad87d3c8b2c..f1123c95d174 100644
--- a/arch/x86/events/perf_event.h
+++ b/arch/x86/events/perf_event.h
@@ -115,7 +115,23 @@ static inline bool is_topdown_event(struct perf_event *event)
 	return is_metric_event(event) || is_slots_event(event);
 }
 
-int is_x86_event(struct perf_event *event);
+static inline bool is_x86_pmu(struct pmu *pmu)
+{
+	/*
+	 * For a non-hybrid platforms, the type of X86 pmu is
+	 * always PERF_TYPE_RAW.
+	 * For a hybrid platform, the PERF_PMU_CAP_EXTENDED_HW_TYPE
+	 * is a unique capability for the X86 PMU.
+	 * Use them to detect a X86 event.
+	 */
+	return pmu->type == PERF_TYPE_RAW ||
+	      (pmu->capabilities & PERF_PMU_CAP_EXTENDED_HW_TYPE);
+}
+
+static inline bool is_x86_event(struct perf_event *event)
+{
+	return is_x86_pmu(event->pmu);
+}
 
 static inline bool check_leader_group(struct perf_event *leader, int flags)
 {
@@ -779,6 +795,7 @@ struct x86_hybrid_pmu {
 
 static __always_inline struct x86_hybrid_pmu *hybrid_pmu(struct pmu *pmu)
 {
+	BUG_ON(!is_x86_pmu(pmu));
 	return container_of(pmu, struct x86_hybrid_pmu, pmu);
 }
 
-- 
2.53.0.851.ga537e3e6e9-goog