linux-kernel - Re: [patch V3 53/66] x86/fpu: Hook up PKRU into ptrace()

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Message-ID: <YNIXWFkGbJWr3Otv@zn.tnic>
Date:   Tue, 22 Jun 2021 19:01:12 +0200
From:   Borislav Petkov <bp@...e.de>
To:     Thomas Gleixner <tglx@...utronix.de>
Cc:     LKML <linux-kernel@...r.kernel.org>,
        Andy Lutomirski <luto@...nel.org>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Fenghua Yu <fenghua.yu@...el.com>,
        Tony Luck <tony.luck@...el.com>,
        Yu-cheng Yu <yu-cheng.yu@...el.com>,
        Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
        Peter Zijlstra <peterz@...radead.org>,
        Kan Liang <kan.liang@...ux.intel.com>
Subject: Re: [patch V3 53/66] x86/fpu: Hook up PKRU into ptrace()

On Fri, Jun 18, 2021 at 04:19:16PM +0200, Thomas Gleixner wrote:
> From: Dave Hansen <dave.hansen@...ux.intel.com>
> 
> One nice thing about having PKRU be XSAVE-managed is that it gets naturally
> exposed into the XSAVE-using ABIs.  Now that XSAVE will not be used to
> manage PKRU, these ABIs need to be manually enabled to deal with PKRU.
> 
> ptrace() uses copy_uabi_xstate_to_kernel() to collect the tracee's
> XSTATE. As PKRU is not in the task's XSTATE buffer, use task->thread.pkru
> for filling in up the ptrace buffer.
> 
> Signed-off-by: Dave Hansen <dave.hansen@...ux.intel.com>
> Signed-off-by: Thomas Gleixner <tglx@...utronix.de>
> ---
>  arch/x86/include/asm/fpu/xstate.h |    2 +-
>  arch/x86/kernel/fpu/regset.c      |   10 ++++------
>  arch/x86/kernel/fpu/xstate.c      |   25 ++++++++++++++++++-------
>  3 files changed, 23 insertions(+), 14 deletions(-)

Reviewed-by: Borislav Petkov <bp@...e.de>

-- 
Regards/Gruss,
    Boris.

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