linux-kernel - Re: [patch 01/10] x86/fpu/signal: Clarify exception handling in restore_fpregs_from

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Message-ID: <87o89ccmyu.ffs@tglx>
Date:   Wed, 01 Sep 2021 17:52:25 +0200
From:   Thomas Gleixner <tglx@...utronix.de>
To:     Linus Torvalds <torvalds@...ux-foundation.org>,
        Al Viro <viro@...iv.linux.org.uk>,
        Dan Williams <dan.j.williams@...el.com>
Cc:     Borislav Petkov <bp@...en8.de>,
        LKML <linux-kernel@...r.kernel.org>,
        the arch/x86 maintainers <x86@...nel.org>,
        Jarkko Sakkinen <jarkko@...nel.org>,
        Sean Christopherson <seanjc@...gle.com>,
        Dave Hansen <dave.hansen@...ux.intel.com>
Subject: Re: [patch 01/10] x86/fpu/signal: Clarify exception handling in
 restore_fpregs_from_user()

On Wed, Sep 01 2021 at 14:00, Thomas Gleixner wrote:
>
> commit b2f9d678e28c ("x86/mce: Check for faults tagged in
> EXTABLE_CLASS_FAULT exception table entries") made use of this in MCE to
> allow in kernel recovery. The only thing it uses is checking the
> exception handler type.
>
> Bah. I'll fix that up to make that less obscure.
>
> The remaining two use cases (SGX and FPU) make use of the stored trap
> number.

Though while for the FPU use case we really want to handle the #MC case,
it's not clear to me whether this is actually correct for SGX.

Jarkko, Sean, Dave?

Thanks,

        tglx