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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>
This commit is contained in:
Marc Zyngier 2015-06-12 12:06:36 +01:00 committed by Catalin Marinas
parent 73bf8412e4
commit 94a9e04aa1
2 changed files with 23 additions and 1 deletions
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8
arch/arm64/include/asm/cpufeature.h
View File

@ -24,8 +24,9 @@
#define ARM64_WORKAROUND_CLEAN_CACHE 0
#define ARM64_WORKAROUND_DEVICE_LOAD_ACQUIRE 1
#define ARM64_WORKAROUND_845719 2
#define ARM64_HAS_SYSREG_GIC_CPUIF 3
#define ARM64_NCAPS 3
#define ARM64_NCAPS 4
#ifndef __ASSEMBLY__
@ -38,6 +39,11 @@ struct arm64_cpu_capabilities {
u32 midr_model;
u32 midr_range_min, midr_range_max;
};
struct { /* Feature register checking */
u64 register_mask;
u64 register_value;
};
};
};

16
arch/arm64/kernel/cpufeature.c
View File

@ -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),
},
{},
};