2 files changed, 37 insertions, 9 deletions

diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 94b8f7fc3310..817ce3365e20 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -985,8 +985,16 @@ void update_cpu_capabilities(const struct arm64_cpu_capabilities *caps,
  */
 void __init enable_cpu_capabilities(const struct arm64_cpu_capabilities *caps)
 {
-	for (; caps->matches; caps++)
-		if (caps->enable && cpus_have_cap(caps->capability))
+	for (; caps->matches; caps++) {
+		unsigned int num = caps->capability;
+
+		if (!cpus_have_cap(num))
+			continue;
+
+		/* Ensure cpus_have_const_cap(num) works */
+		static_branch_enable(&cpu_hwcap_keys[num]);
+
+		if (caps->enable) {
 			/*
 			 * Use stop_machine() as it schedules the work allowing
 			 * us to modify PSTATE, instead of on_each_cpu() which
@@ -994,6 +1002,8 @@ void __init enable_cpu_capabilities(const struct arm64_cpu_capabilities *caps)
 			 * we return.
 			 */
 			stop_machine(caps->enable, NULL, cpu_online_mask);
+		}
+	}
 }
 
 /*
@@ -1096,6 +1106,14 @@ static void __init setup_feature_capabilities(void)
 	enable_cpu_capabilities(arm64_features);
 }
 
+DEFINE_STATIC_KEY_FALSE(arm64_const_caps_ready);
+EXPORT_SYMBOL(arm64_const_caps_ready);
+
+static void __init mark_const_caps_ready(void)
+{
+	static_branch_enable(&arm64_const_caps_ready);
+}
+
 /*
  * Check if the current CPU has a given feature capability.
  * Should be called from non-preemptible context.
@@ -1131,6 +1149,7 @@ void __init setup_cpu_features(void)
 	/* Set the CPU feature capabilies */
 	setup_feature_capabilities();
 	enable_errata_workarounds();
+	mark_const_caps_ready();
 	setup_elf_hwcaps(arm64_elf_hwcaps);
 
 	if (system_supports_32bit_el0())
diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c
index bcc79471b38e..83a1b1ad189f 100644
--- a/arch/arm64/kernel/perf_event.c
+++ b/arch/arm64/kernel/perf_event.c
@@ -877,15 +877,24 @@ static int armv8pmu_set_event_filter(struct hw_perf_event *event,
 
 	if (attr->exclude_idle)
 		return -EPERM;
-	if (is_kernel_in_hyp_mode() &&
-	    attr->exclude_kernel != attr->exclude_hv)
-		return -EINVAL;
+
+	/*
+	 * If we're running in hyp mode, then we *are* the hypervisor.
+	 * Therefore we ignore exclude_hv in this configuration, since
+	 * there's no hypervisor to sample anyway. This is consistent
+	 * with other architectures (x86 and Power).
+	 */
+	if (is_kernel_in_hyp_mode()) {
+		if (!attr->exclude_kernel)
+			config_base |= ARMV8_PMU_INCLUDE_EL2;
+	} else {
+		if (attr->exclude_kernel)
+			config_base |= ARMV8_PMU_EXCLUDE_EL1;
+		if (!attr->exclude_hv)
+			config_base |= ARMV8_PMU_INCLUDE_EL2;
+	}
 	if (attr->exclude_user)
 		config_base |= ARMV8_PMU_EXCLUDE_EL0;
-	if (!is_kernel_in_hyp_mode() && attr->exclude_kernel)
-		config_base |= ARMV8_PMU_EXCLUDE_EL1;
-	if (!attr->exclude_hv)
-		config_base |= ARMV8_PMU_INCLUDE_EL2;
 
 	/*
 	 * Install the filter into config_base as this is used to