[PATCH v6 5/5] arm64: futex: support futex with FEAT_LSUI

[Yeoreum Yun]

Hi Catalin,
> On Mon, Aug 11, 2025 at 05:36:35PM +0100, Yeoreum Yun wrote:
> > +#ifdef CONFIG_AS_HAS_LSUI
> > +
> > +#define __LSUI_PREAMBLE	".arch_extension lsui\n"
> > +
> > +#define LSUI_FUTEX_ATOMIC_OP(op, asm_op, mb)				\
> > +static __always_inline int						\
> > +__lsui_futex_atomic_##op(int oparg, u32 __user *uaddr, int *oval)	\
> > +{									\
> > +	int ret = 0;							\
> > +	int val;							\
> > +									\
> > +	mte_enable_tco();						\
>

> The reason uaccess_disable_privileged() sets the MTE TCO (tag check
> override) is because the user and the kernel may have different settings
> for tag checking. If we use the user instructions provided by FEAT_LSUI,
> we leave the MTE checking as is.
>
> The same comment for all the other functions here.

You're right. Thanks for catching this :)

--
Sincerely,
Yeoreum Yun