On Wed, 04 Aug 2021 09:58:14 +0100,
Oliver Upton <oupton@xxxxxxxxxx> wrote:
>
> Introduce a new cpucap to indicate if the system supports full enhanced
> counter virtualization (i.e. ID_AA64MMFR0_EL1.ECV==0x2).
>
> Signed-off-by: Oliver Upton <oupton@xxxxxxxxxx>
> ---
> arch/arm64/include/asm/sysreg.h | 2 ++
> arch/arm64/kernel/cpufeature.c | 10 ++++++++++
> arch/arm64/tools/cpucaps | 1 +
> 3 files changed, 13 insertions(+)
>
> diff --git a/arch/arm64/include/asm/sysreg.h b/arch/arm64/include/asm/sysreg.h
> index 7b9c3acba684..4dfc44066dfb 100644
> --- a/arch/arm64/include/asm/sysreg.h
> +++ b/arch/arm64/include/asm/sysreg.h
> @@ -847,6 +847,8 @@
> #define ID_AA64MMFR0_ASID_SHIFT 4
> #define ID_AA64MMFR0_PARANGE_SHIFT 0
>
> +#define ID_AA64MMFR0_ECV_VIRT 0x1
> +#define ID_AA64MMFR0_ECV_PHYS 0x2
> #define ID_AA64MMFR0_TGRAN4_NI 0xf
> #define ID_AA64MMFR0_TGRAN4_SUPPORTED 0x0
> #define ID_AA64MMFR0_TGRAN64_NI 0xf
> diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
> index 0ead8bfedf20..94c349e179d3 100644
> --- a/arch/arm64/kernel/cpufeature.c
> +++ b/arch/arm64/kernel/cpufeature.c
> @@ -2301,6 +2301,16 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
> .matches = has_cpuid_feature,
> .min_field_value = 1,
> },
> + {
> + .desc = "Enhanced Counter Virtualization (Physical)",
> + .capability = ARM64_ECV,
> + .type = ARM64_CPUCAP_SYSTEM_FEATURE,
> + .sys_reg = SYS_ID_AA64MMFR0_EL1,
> + .sign = FTR_UNSIGNED,
> + .field_pos = ID_AA64MMFR0_ECV_SHIFT,
> + .matches = has_cpuid_feature,
> + .min_field_value = ID_AA64MMFR0_ECV_PHYS,
> + },
> {},
> };
>
> diff --git a/arch/arm64/tools/cpucaps b/arch/arm64/tools/cpucaps
> index 49305c2e6dfd..d819ea614da5 100644
> --- a/arch/arm64/tools/cpucaps
> +++ b/arch/arm64/tools/cpucaps
> @@ -3,6 +3,7 @@
> # Internal CPU capabilities constants, keep this list sorted
>
> BTI
> +ECV
> # Unreliable: use system_supports_32bit_el0() instead.
> HAS_32BIT_EL0_DO_NOT_USE
> HAS_32BIT_EL1
As discussed in another context, we probably want both ECV and ECV2 to
distinguish the two feature sets that ECV has so far.
Thanks,
M.
--
Without deviation from the norm, progress is not possible.
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