[PATCH v4 10/29] arm64: enable the Permission Overlay Extension for EL0

[Dave Martin]

On Fri, May 03, 2024 at 02:01:28PM +0100, Joey Gouly wrote:
> Expose a HWCAP and ID_AA64MMFR3_EL1_S1POE to userspace, so they can be used to
> check if the CPU supports the feature.
> 
> Signed-off-by: Joey Gouly <joey.gouly at arm.com>
> Cc: Catalin Marinas <catalin.marinas at arm.com>
> Cc: Will Deacon <will at kernel.org>
> ---
> 
> This takes the last bit of HWCAP2, is this fine? What can we do about more features in the future?
> 
> 
>  Documentation/arch/arm64/elf_hwcaps.rst |  2 ++
>  arch/arm64/include/asm/hwcap.h          |  1 +
>  arch/arm64/include/uapi/asm/hwcap.h     |  1 +
>  arch/arm64/kernel/cpufeature.c          | 14 ++++++++++++++
>  arch/arm64/kernel/cpuinfo.c             |  1 +
>  5 files changed, 19 insertions(+)
> 
> diff --git a/Documentation/arch/arm64/elf_hwcaps.rst b/Documentation/arch/arm64/elf_hwcaps.rst
> index 448c1664879b..694f67fa07d1 100644
> --- a/Documentation/arch/arm64/elf_hwcaps.rst
> +++ b/Documentation/arch/arm64/elf_hwcaps.rst
> @@ -365,6 +365,8 @@ HWCAP2_SME_SF8DP2
>  HWCAP2_SME_SF8DP4
>      Functionality implied by ID_AA64SMFR0_EL1.SF8DP4 == 0b1.
>  
> +HWCAP2_POE
> +    Functionality implied by ID_AA64MMFR3_EL1.S1POE == 0b0001.

Nit: unintentionally dropped blank line before the section heading?

>  
>  4. Unused AT_HWCAP bits
>  -----------------------

[...]

Cheers
---Dave