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References: <20230123220500.21077-1-kirill.shutemov@linux.intel.com> <20230123220500.21077-9-kirill.shutemov@linux.intel.com>
In-Reply-To: <20230123220500.21077-9-kirill.shutemov@linux.intel.com>
From:   Alexander Potapenko <glider@google.com>
Date:   Thu, 9 Feb 2023 15:12:01 +0100
Message-ID: <CAG_fn=Wzs5341St=W+16OSaaZ711nymv2K+-C0fxqgOo45LwqQ@mail.gmail.com>
Subject: Re: [PATCHv15 08/17] x86/mm: Provide arch_prctl() interface for LAM
To:     "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc:     Dave Hansen <dave.hansen@linux.intel.com>,
        Andy Lutomirski <luto@kernel.org>,
        Peter Zijlstra <peterz@infradead.org>, x86@kernel.org,
        Kostya Serebryany <kcc@google.com>,
        Andrey Ryabinin <ryabinin.a.a@gmail.com>,
        Andrey Konovalov <andreyknvl@gmail.com>,
        Taras Madan <tarasmadan@google.com>,
        Dmitry Vyukov <dvyukov@google.com>,
        "H . J . Lu" <hjl.tools@gmail.com>,
        Andi Kleen <ak@linux.intel.com>,
        Rick Edgecombe <rick.p.edgecombe@intel.com>,
        Bharata B Rao <bharata@amd.com>,
        Jacob Pan <jacob.jun.pan@linux.intel.com>,
        Ashok Raj <ashok.raj@intel.com>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org
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On Mon, Jan 23, 2023 at 11:05 PM Kirill A. Shutemov
<kirill.shutemov@linux.intel.com> 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@linux.intel.com>
> Acked-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Tested-by: Alexander Potapenko <glider@google.com>