Re: [PATCH 1/4] arm64: cpufeature: Effectively expose FRINT capability to userspace

[Will Deacon]

On Thu, Oct 03, 2019 at 12:12:08PM +0100, Julien Grall wrote:
> The HWCAP framework will detect a new capability based on the sanitized
> version of the ID registers.
> 
> Sanitization is based on a whitelist, so any field not described will end
> up to be zeroed.
> 
> At the moment, ID_AA64ISAR1_EL1.FRINTTS is not described in
> ftr_id_aa64isar1. This means the field will be zeroed and therefore the
> userspace will not be able to see the HWCAP even if the hardware
> supports the feature.
> 
> This can be fixed by describing the field in ftr_id_aa64isar1.
> 
> Fixes: ca9503fc9e98 ("arm64: Expose FRINT capabilities to userspace")
> Signed-off-by: Julien Grall <julien.grall@xxxxxxx>
> Cc: mark.brown@xxxxxxx
> ---
>  arch/arm64/kernel/cpufeature.c | 1 +
>  1 file changed, 1 insertion(+)

D'oh, we should've caught this in testing. Queued as a fix.

Will