[PATCH] arm64/sysreg: Fix BWE field encoding in ID_AA64DFR2_EL1

[Oliver Upton]

On Tue, Jun 30, 2026 at 10:23:47PM +0000, Jia He wrote:
> Commit 93d7356e4b30 ("arm64: sysreg: Describe ID_AA64DFR2_EL1 fields")
> encodes the FEAT_BWE2 value of the BWE field as '0b0002'. Binary
> literals only accept the digits 0 and 1, so the intended value is 2,
> i.e. 0b0010.
> 
> The macro generated by gen-sysreg.awk currently expands to
> 	#define ID_AA64DFR2_EL1_BWE_FEAT_BWE2 UL(0b0002)
> is not legal C and would fail to compile if any in-tree code referenced
> it. At present no caller uses this enum value, so the kernel still
> builds cleanly, but the bug is latent.
> 
> Fix the typo by using the correct binary literal 0b0010.
> 
> Cc: Bin Guo <guobin at linux.alibaba.com>
> Fixes: 93d7356e4b30 ("arm64: sysreg: Describe ID_AA64DFR2_EL1 fields")
> Signed-off-by: Jia He <justin.he at arm.com>
> Reviewed-by: Mark Brown <broonie at kernel.org>

Hah, I screwed that up pretty good!

Reviewed-by: Oliver Upton <oupton at kernel.org>

> ---
>  arch/arm64/tools/sysreg | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/arm64/tools/sysreg b/arch/arm64/tools/sysreg
> index bc1788b1662b..7cb61aca3797 100644
> --- a/arch/arm64/tools/sysreg
> +++ b/arch/arm64/tools/sysreg
> @@ -1806,7 +1806,7 @@ Res0	15:8
>  UnsignedEnum	7:4	BWE
>  	0b0000	NI
>  	0b0001	FEAT_BWE
> -	0b0002	FEAT_BWE2
> +	0b0010	FEAT_BWE2
>  EndEnum
>  UnsignedEnum	3:0	STEP
>  	0b0000	NI
> -- 
> 2.34.1
>