Re: [PATCH v2 2/2] arm64: Expose Arm v8.4 features

From: Will Deacon
Date: Mon Feb 26 2018 - 13:05:29 EST


On Wed, Feb 07, 2018 at 02:21:06PM +0000, Suzuki K Poulose wrote:
> Expose the new features introduced by Arm v8.4 extensions to
> Arm v8-A profile.
>
> These include :
>
> 1) Data indpendent timing of instructions. (DIT, exposed as HWCAP_DIT)
> 2) Unaligned atomic instructions and Single-copy atomicity of loads
> and stores. (AT, expose as HWCAP_USCAT)
> 3) LDAPR and STLR instructions with immediate offsets (extension to
> LRCPC, exposed as HWCAP_ILRCPC)
> 4) Flag manipulation instructions (TS, exposed as HWCAP_FLAGM).

Please resend this but continuing with the default of FTR_STRICT, as we
currently have. That way this can be merged while we work out what we want
to do there.

> While at it get rid of the RES0 entries in the cpu-feature-registers.txt
> documentation, as:
> 1) We care only about the user visible fields.
> 2) The field may not be up-to-date
> 3) We already explain the rules of the fields if it is not visible.

Please spin this part as a separate patch.

Will