arm64: alternative: Introduce feature for GICv3 CPU interface
Add a new item to the feature set (ARM64_HAS_SYSREG_GIC_CPUIF)
to indicate that we have a system register GIC CPU interface
This will help KVM switching to alternative instruction patching.
Reviewed-by: Andre Przywara <andre.przywara@arm.com>
Reviewed-by: Christoffer Dall <christoffer.dall@linaro.org>
Acked-by: Will Deacon <will.deacon@arm.com>
Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
Signed-off-by: Catalin Marinas <catalin.marinas@arm.com>
diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
index 3d9967e..5ad86ce 100644
--- a/arch/arm64/kernel/cpufeature.c
+++ b/arch/arm64/kernel/cpufeature.c
@@ -22,7 +22,23 @@
#include <asm/cpu.h>
#include <asm/cpufeature.h>
+static bool
+has_id_aa64pfr0_feature(const struct arm64_cpu_capabilities *entry)
+{
+ u64 val;
+
+ val = read_cpuid(id_aa64pfr0_el1);
+ return (val & entry->register_mask) == entry->register_value;
+}
+
static const struct arm64_cpu_capabilities arm64_features[] = {
+ {
+ .desc = "GIC system register CPU interface",
+ .capability = ARM64_HAS_SYSREG_GIC_CPUIF,
+ .matches = has_id_aa64pfr0_feature,
+ .register_mask = (0xf << 24),
+ .register_value = (1 << 24),
+ },
{},
};