Re: [PATCH RESEND v7 3/6] arm64: Kconfig: add LSUI Kconfig

Catalin Marinas
2025-09-12T16:24:16Z

On Sat, Aug 16, 2025 at 04:19:26PM +0100, 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.

The subject could be improved slightly: Detect toolchain support for
LSUI.

>
> Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
> ---
> arch/arm64/Kconfig | 5 +++++
> 1 file changed, 5 insertions(+)
>
> diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig
> index e9bbfacc35a6..c474de3dce02 100644
> --- a/arch/arm64/Kconfig
> +++ b/arch/arm64/Kconfig
> @@ -2239,6 +2239,11 @@ config ARM64_GCS
>
> endmenu # "v9.4 architectural features"
>
> +config AS_HAS_LSUI
> + def_bool $(as-instr,.arch_extension lsui)
> + help
> + Supported by LLVM 20 and later, not yet supported by GNU AS.

binutils 2.45 added support for LSUI.

Nitpick: we tend to add a two-space indentation from "help".

Otherwise it looks fine:

Reviewed-by: Catalin Marinas <catalin.marinas@arm.com>