Re: [PATCH v3 5/7] arm64: cpufeature: Track 32bit EL0 support

From: Will Deacon
Date: Thu Apr 14 2016 - 12:43:12 EST


On Thu, Mar 31, 2016 at 06:27:33PM +0100, Suzuki K Poulose wrote:
> Add cpu_hwcap bit for keeping track of the support for 32bit EL0.
>
> Tested-by: Yury Norov <ynorov@xxxxxxxxxxxxxxxxxx>
> Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
> ---
> arch/arm64/include/asm/cpufeature.h | 8 +++++++-
> arch/arm64/kernel/cpufeature.c | 9 +++++++++
> 2 files changed, 16 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
> index 7f64285..ca8fb4b 100644
> --- a/arch/arm64/include/asm/cpufeature.h
> +++ b/arch/arm64/include/asm/cpufeature.h
> @@ -35,8 +35,9 @@
> #define ARM64_ALT_PAN_NOT_UAO 10
> #define ARM64_HAS_VIRT_HOST_EXTN 11
> #define ARM64_WORKAROUND_CAVIUM_27456 12
> +#define ARM64_HAS_32BIT_EL0 13
>
> -#define ARM64_NCAPS 13
> +#define ARM64_NCAPS 14
>
> #ifndef __ASSEMBLY__
>
> @@ -192,6 +193,11 @@ static inline bool cpu_supports_mixed_endian_el0(void)
> return id_aa64mmfr0_mixed_endian_el0(read_cpuid(ID_AA64MMFR0_EL1));
> }
>
> +static inline bool system_supports_32bit_el0(void)
> +{
> + return cpus_have_cap(ARM64_HAS_32BIT_EL0);
> +}
> +
> static inline bool system_supports_mixed_endian_el0(void)
> {
> return id_aa64mmfr0_mixed_endian_el0(read_system_reg(SYS_ID_AA64MMFR0_EL1));
> diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c
> index cfc0cfd..739314b 100644
> --- a/arch/arm64/kernel/cpufeature.c
> +++ b/arch/arm64/kernel/cpufeature.c
> @@ -733,6 +733,15 @@ static const struct arm64_cpu_capabilities arm64_features[] = {
> .capability = ARM64_HAS_VIRT_HOST_EXTN,
> .matches = runs_at_el2,
> },
> + {
> + .desc = "32bit EL0 Support",

Nit: missing hyphen (32-bit).

Will