Re: [PATCH v3 2/3] arm64: sysreg: Correct sign definitions for EIESB and DoubleLock

[Mark Rutland <mark.rutland@arm.com>]

On Fri, Aug 29, 2025 at 10:51:42AM +0100, Fuad Tabba wrote:
> The `ID_AA64MMFR4_EL1.EIESB` field, is an unsigned enumeration, but was
> incorrectly defined as a `SignedEnum` when introduced in commit
> cfc680bb04c5 ("arm64: sysreg: Add layout for ID_AA64MMFR4_EL1"). This is
> corrected to `UnsignedEnum`.
> 
> Conversely, the `ID_AA64DFR0_EL1.DoubleLock` field, is a signed
> enumeration, but was incorrectly defined as an `UnsignedEnum`. This is
> corrected to `SignedEnum`, which wasn't correctly set when annotated as
> such in commit ad16d4cf0b4f ("arm64/sysreg: Initial unsigned annotations
> for ID registers").
> 
> Signed-off-by: Fuad Tabba <tabba@google.com>
> ---
> Note: No active users in the kernel for these two fields yet. pKVM
> checks DoubleLock, but only for protected VMs, which aren't enabled
> upstream yet. Hence no Fixes tag.

I have no strong feelings either way on that, so FWIW:

Acked-by: Mark Rutland <mark.rutland@arm.com>

Mark.

> ---
>  arch/arm64/tools/sysreg | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/arch/arm64/tools/sysreg b/arch/arm64/tools/sysreg
> index f1a012ee0db6..d396fa587ec1 100644
> --- a/arch/arm64/tools/sysreg
> +++ b/arch/arm64/tools/sysreg
> @@ -1693,7 +1693,7 @@ UnsignedEnum	43:40	TraceFilt
>  	0b0000	NI
>  	0b0001	IMP
>  EndEnum
> -UnsignedEnum	39:36	DoubleLock
> +SignedEnum	39:36	DoubleLock
>  	0b0000	IMP
>  	0b1111	NI
>  EndEnum
> @@ -2409,7 +2409,7 @@ UnsignedEnum	11:8	ASID2
>  	0b0000	NI
>  	0b0001	IMP
>  EndEnum
> -SignedEnum	7:4	EIESB
> +UnsignedEnum	7:4	EIESB
>  	0b0000	NI
>  	0b0001	ToEL3
>  	0b0010	ToELx
> -- 
> 2.51.0.338.gd7d06c2dae-goog
> 
>