Re: [PATCHv15 08/17] x86/mm: Provide arch_prctl() interface for LAM

[Alexander Potapenko]

On Mon, Jan 23, 2023 at 11:05 PM Kirill A. Shutemov
<kirill.shutemov@xxxxxxxxxxxxxxx> wrote:
>
> Add a few of arch_prctl() handles:
>
>  - ARCH_ENABLE_TAGGED_ADDR enabled LAM. The argument is required number
>    of tag bits. It is rounded up to the nearest LAM mode that can
>    provide it. For now only LAM_U57 is supported, with 6 tag bits.
>
>  - ARCH_GET_UNTAG_MASK returns untag mask. It can indicates where tag
>    bits located in the address.
>
>  - ARCH_GET_MAX_TAG_BITS returns the maximum tag bits user can request.
>    Zero if LAM is not supported.
>
> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
> Acked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Tested-by: Alexander Potapenko <glider@xxxxxxxxxx>