[PATCH v11 RESEND 4/9] arm64: Kconfig: Detect toolchain support for LSUI

[Will Deacon]

On Sun, Dec 14, 2025 at 11:22:43AM +0000, Yeoreum Yun wrote:
> Since Armv9.6, FEAT_LSUI supplies the load/store instructions for
> previleged level to access to access user memory without clearing
> PSTATE.PAN bit.
> It's enough to add CONFIG_AS_HAS_LSUI only because the code for LSUI uses
> individual `.arch_extension` entries.
> 
> Signed-off-by: Yeoreum Yun <yeoreum.yun at arm.com>
> Reviewed-by: Catalin Marinas <catalin.marinas at arm.com>
> ---
>  arch/arm64/Kconfig | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index 93173f0a09c7..36e87a1a1b5c 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -2227,6 +2227,11 @@ config ARM64_GCS
> 
>  endmenu # "ARMv9.4 architectural features"
> 
> +config AS_HAS_LSUI
> +	def_bool $(as-instr,.arch_extension lsui)
> +	help
> +	  Supported by LLVM 20+ and binutils 2.45+.

This is an internal Kconfig variable so please drop the help text.

Will