On Mon, Sep 30, 2019 at 09:57:38AM +0800, Jia He wrote:
> We unconditionally set the HW_AFDBM capability and only enable it on
> CPUs which really have the feature. But sometimes we need to know
> whether this cpu has the capability of HW AF. So decouple AF from
> DBM by new helper cpu_has_hw_af().
>
> Signed-off-by: Jia He <justin.he@xxxxxxx>
> Suggested-by: Suzuki Poulose <Suzuki.Poulose@xxxxxxx>
> Reviewed-by: Catalin Marinas <catalin.marinas@xxxxxxx>
> ---
> arch/arm64/include/asm/cpufeature.h | 10 ++++++++++
> 1 file changed, 10 insertions(+)
>
> diff --git a/arch/arm64/include/asm/cpufeature.h b/arch/arm64/include/asm/cpufeature.h
> index 9cde5d2e768f..949bc7c85030 100644
> --- a/arch/arm64/include/asm/cpufeature.h
> +++ b/arch/arm64/include/asm/cpufeature.h
> @@ -659,6 +659,16 @@ static inline u32 id_aa64mmfr0_parange_to_phys_shift(int parange)
> default: return CONFIG_ARM64_PA_BITS;
> }
> }
> +
> +/* Check whether hardware update of the Access flag is supported */
> +static inline bool cpu_has_hw_af(void)
> +{
> + if (IS_ENABLED(CONFIG_ARM64_HW_AFDBM))
> + return read_cpuid(ID_AA64MMFR1_EL1) & 0xf;
0xf? I think we should have a mask in sysreg.h for this constant.
Will
