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From: Borislav Petkov <bp@alien8.de>
To: Andy Lutomirski <luto@amacapital.net>
Cc: Matt Fleming <matt.fleming@intel.com>,
	"H. Peter Anvin" <hpa@zytor.com>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	Ingo Molnar <mingo@kernel.org>,
	Ricardo Neri <ricardo.neri-calderon@linux.intel.com>,
	"tglx@linutronix.de" <tglx@linutronix.de>,
	"linux-tip-commits@vger.kernel.org" 
	<linux-tip-commits@vger.kernel.org>
Subject: Re: [tip:x86/efi] x86/efi: Check for unsafe dealing with FPU state in irq ctxt
Date: Thu, 5 Jun 2014 18:18:34 +0200	[thread overview]
Message-ID: <20140605161834.GF16642@pd.tnic> (raw)
In-Reply-To: <CALCETrUors-39hUxS9Bg-dh+DzMcmPOs=6t998sbCVjqXYgyug@mail.gmail.com>

On Thu, Jun 05, 2014 at 09:14:51AM -0700, Andy Lutomirski wrote:
> Is this NMI pstore thing done from any context that's supposed to be
> recoverable? It's always safe to use the FPU and then panic :)

Right :)

> Anyway, if we're just talking about EFI, there's an easier solution:
> just preallocate a per-cpu FPU context for EFI and make the whole mess
> be local to the EFI code.  For crypto, that's not so good.

This is probably something for Matt to decide but it sounds doable. If
I'd have to guess, sooner or later we will need to do proper FPU context
handling for EFI as I don't see anything stopping it from using FPU
insns. At least we won't. :-)

-- 
Regards/Gruss,
    Boris.

Sent from a fat crate under my desk. Formatting is fine.
--

  reply	other threads:[~2014-06-05 16:20 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <tip-baa916f39b50ad91661534652110df40396acda0@git.kernel.org>
2014-06-04 22:17 ` [tip:x86/efi] x86/efi: Check for unsafe dealing with FPU state in irq ctxt H. Peter Anvin
2014-06-04 22:49   ` Borislav Petkov
2014-06-04 22:52     ` H. Peter Anvin
2014-06-05  0:19     ` Andy Lutomirski
2014-06-05  7:18       ` Borislav Petkov
2014-06-05  8:49         ` Matt Fleming
2014-06-05  9:02           ` Borislav Petkov
2014-06-05 15:44             ` Andy Lutomirski
2014-06-05 15:53               ` Borislav Petkov
2014-06-05 16:01                 ` Andy Lutomirski
2014-06-05 16:08                   ` Borislav Petkov
2014-06-05 16:14                     ` Andy Lutomirski
2014-06-05 16:18                       ` Borislav Petkov [this message]
2014-06-05 16:31                         ` H. Peter Anvin
2014-06-05 16:35                           ` Andy Lutomirski
2014-06-05 16:43                             ` H. Peter Anvin
2014-06-05 16:37                           ` Borislav Petkov
2014-06-05 16:43                             ` H. Peter Anvin
2014-06-05 16:44                               ` Borislav Petkov

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