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

Yeoreum Yun
2025-09-15T11:42:30Z

Hi Will,

> On Mon, Sep 15, 2025 at 11:42:12AM +0100, Yeoreum Yun wrote:
> > > 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>
> >
> > Thanks! I'll change the Nitpick and send again.
>
> Please don't resend until we've concluded on the CAS discussion.

Yes. so I'm waiting for your comment for:
- https://lore.kernel.org/all/aMfZI2VVV5zEsTna@e129823.arm.com/
- https://lore.kernel.org/all/aMfrR0vserl%2FhfZ3@e129823.arm.com/

Thanks.

--
Sincerely,
Yeoreum Yun