linux-kernel - Re: [tip:x86/fpu] x86/fpu: Don't export __kernel_fpu

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Message-ID: <20181203220841.GB4794@zn.tnic>
Date:   Mon, 3 Dec 2018 23:08:41 +0100
From:   Borislav Petkov <bp@...en8.de>
To:     Ard Biesheuvel <ard.biesheuvel@...aro.org>,
        Sebastian Andrzej Siewior <bigeasy@...utronix.de>
Cc:     Dave Hansen <dave.hansen@...ux.intel.com>,
        Ingo Molnar <mingo@...hat.com>,
        the arch/x86 maintainers <x86@...nel.org>, nstange@...e.de,
        Rik van Riel <riel@...riel.com>,
        KVM devel mailing list <kvm@...r.kernel.org>,
        "Jason A. Donenfeld" <Jason@...c4.com>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Ingo Molnar <mingo@...nel.org>,
        Radim Krčmář <rkrcmar@...hat.com>,
        "H. Peter Anvin" <hpa@...or.com>,
        Thomas Gleixner <tglx@...utronix.de>,
        Andy Lutomirski <luto@...nel.org>,
        Borislav Petkov <bp@...e.de>,
        linux-efi <linux-efi@...r.kernel.org>,
        Paolo Bonzini <pbonzini@...hat.com>,
        linux-tip-commits@...r.kernel.org
Subject: Re: [tip:x86/fpu] x86/fpu: Don't export __kernel_fpu_{begin,end}()

On Mon, Dec 03, 2018 at 10:12:19PM +0100, Ard Biesheuvel wrote:
> > + * Using the FPU in hardirq is not allowed.
> 
> According to the documentation in x86/kernel/fpu/core.c, this is not
> true. So which one is accurate?

I think you mean the irq from user mode... Yap, we do allow that.

Sebastian?

Thx.

-- 
Regards/Gruss,
    Boris.

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