From: "H. Peter Anvin" <hpa@zytor.com>
To: Borislav Petkov <bp@alien8.de>
Cc: Andy Lutomirski <luto@amacapital.net>,
Matt Fleming <matt.fleming@intel.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, 05 Jun 2014 09:43:50 -0700 [thread overview]
Message-ID: <53909E46.4020904@zytor.com> (raw)
In-Reply-To: <20140605163711.GG16642@pd.tnic>
On 06/05/2014 09:37 AM, Borislav Petkov wrote:
> On Thu, Jun 05, 2014 at 09:31:12AM -0700, H. Peter Anvin wrote:
>> The bottom line is that we can't call EFI from a context where we can't
>> use the FPU. Or specifically, we can't then resume execution.
>
> Can't we allocate a save-state area, stash the state there and let EFI
> scribble over it? When EFI returns, we scribble over it back assuming it
> has done the saving/restoring on its own.
I'm sorry I don't follow.
-hpa
next prev parent reply other threads:[~2014-06-05 16:44 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
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 [this message]
2014-06-05 16:44 ` Borislav Petkov
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