Hi Marc,
On Thu, Feb 16, 2023 at 6:21 AM Marc Zyngier <maz@xxxxxxxxxx> wrote:
>
> Add the probing code for the FEAT_ECV variant that implements CNTPOFF_EL2.
> Why is it optional is a mystery, but let's try and detect it.
>
> Signed-off-by: Marc Zyngier <maz@xxxxxxxxxx>
> ---
> arch/arm64/kernel/cpufeature.c | 11 +++++++++++
> arch/arm64/tools/cpucaps | 1 +
> 2 files changed, 12 insertions(+)
>
> diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
> index 23bd2a926b74..36852f96898d 100644
> --- a/arch/arm64/kernel/cpufeature.c
> +++ b/arch/arm64/kernel/cpufeature.c
> @@ -2186,6 +2186,17 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
> .sign = FTR_UNSIGNED,
> .min_field_value = 1,
> },
> + {
> + .desc = "Enhanced Counter Virtualization (CNTPOFF)",
> + .capability = ARM64_HAS_ECV_CNTPOFF,
> + .type = ARM64_CPUCAP_SYSTEM_FEATURE,
> + .matches = has_cpuid_feature,
> + .sys_reg = SYS_ID_AA64MMFR0_EL1,
> + .field_pos = ID_AA64MMFR0_EL1_ECV_SHIFT,
> + .field_width = 4,
> + .sign = FTR_UNSIGNED,
> + .min_field_value = 2,
Nit: You might want to use ID_AA64MMFR0_EL1_ECV_CNTPOFF (instead of 2) ?
Reviewed-by: Reiji Watanabe <reijiw@xxxxxxxxxx>
Thank you,
Reiji
> + },
> #ifdef CONFIG_ARM64_PAN
> {
> .desc = "Privileged Access Never",
> diff --git a/arch/arm64/tools/cpucaps b/arch/arm64/tools/cpucaps
> index 82c7e579a8ba..6a26a4678406 100644
> --- a/arch/arm64/tools/cpucaps
> +++ b/arch/arm64/tools/cpucaps
> @@ -23,6 +23,7 @@ HAS_DCPOP
> HAS_DIT
> HAS_E0PD
> HAS_ECV
> +HAS_ECV_CNTPOFF
> HAS_EPAN
> HAS_GENERIC_AUTH
> HAS_GENERIC_AUTH_ARCH_QARMA3
> --
> 2.34.1
>
>
