Skip initialization of PMUv3 remap when EL2 is not available.
Initialization is harmless in EL1 but it is still a weird thing to do.

Signed-off-by: Nick Chan <towinchenmi@gmail.com>
---
 drivers/perf/apple_m1_cpu_pmu.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/perf/apple_m1_cpu_pmu.c b/drivers/perf/apple_m1_cpu_pmu.c
index df9a28ba69dcfad6f33a0d18b620276b910a36ca..b800da3f7f61ffa972fcab5f24b42127f2c55ac6 100644
--- a/drivers/perf/apple_m1_cpu_pmu.c
+++ b/drivers/perf/apple_m1_cpu_pmu.c
@@ -646,8 +646,10 @@ static int m1_pmu_init(struct arm_pmu *cpu_pmu, u32 flags)
 	cpu_pmu->reset		  = m1_pmu_reset;
 	cpu_pmu->set_event_filter = m1_pmu_set_event_filter;
 
-	cpu_pmu->map_pmuv3_event  = m1_pmu_map_pmuv3_event;
-	m1_pmu_init_pmceid(cpu_pmu);
+	if (is_hyp_mode_available()) {
+		cpu_pmu->map_pmuv3_event  = m1_pmu_map_pmuv3_event;
+		m1_pmu_init_pmceid(cpu_pmu);
+	}
 
 	bitmap_set(cpu_pmu->cntr_mask, 0, M1_PMU_NR_COUNTERS);
 	cpu_pmu->attr_groups[ARMPMU_ATTR_GROUP_EVENTS] = &m1_pmu_events_attr_group;

-- 
2.49.0

On Mon, Jun 16, 2025 at 09:31:51AM +0800, Nick Chan wrote:
> Skip initialization of PMUv3 remap when EL2 is not available.
> Initialization is harmless in EL1 but it is still a weird thing to do.

Why is that weird?

Will

Will Deacon 於 2025/7/14 夜晚11:11 寫道:
> On Mon, Jun 16, 2025 at 09:31:51AM +0800, Nick Chan wrote:
>> Skip initialization of PMUv3 remap when EL2 is not available.
>> Initialization is harmless in EL1 but it is still a weird thing to do.
> Why is that weird?

Maybe I could use better wording but if the check is not here, then for Apple A7 which has very
different event mappings, it either has to use the mappings for M1 which is wrong on the hardware,
or declare an a7_pmu_pmceid_map, which would just be dead code since A7's CPU does not
support EL2. Not initializing the mapping in EL1 avoid these problems.

>
> Will
>
Nick Chan

On Mon, Jul 14, 2025 at 11:37:46PM +0800, Nick Chan wrote:
> 
> Will Deacon 於 2025/7/14 夜晚11:11 寫道:
> > On Mon, Jun 16, 2025 at 09:31:51AM +0800, Nick Chan wrote:
> >> Skip initialization of PMUv3 remap when EL2 is not available.
> >> Initialization is harmless in EL1 but it is still a weird thing to do.
> > Why is that weird?
> 
> Maybe I could use better wording but if the check is not here, then for Apple A7 which has very
> different event mappings, it either has to use the mappings for M1 which is wrong on the hardware,
> or declare an a7_pmu_pmceid_map, which would just be dead code since A7's CPU does not
> support EL2. Not initializing the mapping in EL1 avoid these problems.

That's definitely more motivating than what you have :)

Will