Re: [PATCH 1/2] arm64: topology: Prefer PE0 on NVIDIA Olympus SMT cores

diff --git a/arch/arm64/kernel/topology.c b/arch/arm64/kernel/topology.c
index d28438f8b83f1..e5a7a4b2e3844 100644
--- a/arch/arm64/kernel/topology.c
+++ b/arch/arm64/kernel/topology.c

@@ -19,6 +19,8 @@
 #include <linux/init.h>
 #include <linux/percpu.h>
 #include <linux/sched/isolation.h>
+#include <linux/sched/topology.h>
+#include <linux/smp.h>
 #include <linux/xarray.h>
 
 #include <asm/cpu.h>

@@ -44,6 +46,55 @@
 static DEFINE_PER_CPU_READ_MOSTLY(unsigned long, arch_max_freq_scale) =  1UL << (2 * SCHED_CAPACITY_SHIFT);
 static cpumask_var_t amu_fie_cpus;
 
+/*
+ * Switching the active PE on an NVIDIA Olympus SMT core can keep the core in
+ * two-thread active mode, with resources partitioned between the PEs.
+ *
+ * Prefer PE0 so PE1 can remain idle and the core can stay in full-resource
+ * mode. Firmware does not currently describe this preference, so detect
+ * Olympus by MIDR until a firmware interface is available.
+ */