linux/arch/arm64/kernel/cpufeature.c
Marc Zyngier 94a9e04aa1 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>
2015-06-12 15:11:50 +01:00

64 lines
1.6 KiB
C

/*
* Contains CPU feature definitions
*
* Copyright (C) 2015 ARM Ltd.
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with this program. If not, see <http://www.gnu.org/licenses/>.
*/
#define pr_fmt(fmt) "alternatives: " fmt
#include <linux/types.h>
#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),
},
{},
};
void check_cpu_capabilities(const struct arm64_cpu_capabilities *caps,
const char *info)
{
int i;
for (i = 0; caps[i].desc; i++) {
if (!caps[i].matches(&caps[i]))
continue;
if (!cpus_have_cap(caps[i].capability))
pr_info("%s %s\n", info, caps[i].desc);
cpus_set_cap(caps[i].capability);
}
}
void check_local_cpu_features(void)
{
check_cpu_capabilities(arm64_features, "detected feature");
}