linux-kernel - Re: [PATCH 06/23] x86/arch_prctl: Add controls for dynamic XSTATE components

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Message-ID: <YXXNa4FcvbGfCrxr@zn.tnic>
Date:   Sun, 24 Oct 2021 23:17:31 +0200
From:   Borislav Petkov <bp@...en8.de>
To:     "Chang S. Bae" <chang.seok.bae@...el.com>
Cc:     linux-kernel@...r.kernel.org, x86@...nel.org, tglx@...utronix.de,
        dave.hansen@...ux.intel.com, arjan@...ux.intel.com,
        ravi.v.shankar@...el.com
Subject: Re: [PATCH 06/23] x86/arch_prctl: Add controls for dynamic XSTATE
 components

On Thu, Oct 21, 2021 at 03:55:10PM -0700, Chang S. Bae wrote:
> +/**
> + * fpu_xstate_prctl - xstate permission operations
> + * @tsk:	Redundant pointer to current
> + * @option:	A subfunction of arch_prctl()
> + * @arg2:	option argument
> + * Return:	0 if successful; otherwise, an error code
> + *
> + * Option arguments:
> + *
> + * ARCH_GET_XCOMP_SUPP: Pointer to user space u64 to store the info
> + * ARCH_GET_XCOMP_PERM: Pointer to user space u64 to store the info
> + * ARCH_REQ_XCOMP_PERM: Facility number requested
> + *
> + * For facilities which require more than one XSTATE component, the request
> + * must be the highest state component number related to that facility,
> + * e.g. for AMX which requires XFEATURE_XTILE_CFG(17) and
> + * XFEATURE_XTILE_DATA(18) this would be XFEATURE_XTILE_DATA(18).
> + */

Can I pls get this new set of prctl()s documented properly ontop of this
patchset?

I guess Documentation/x86/xstate.rst or so.

Thx.

-- 
Regards/Gruss,
    Boris.

https://people.kernel.org/tglx/notes-about-netiquette