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 17:53:08 +0200 [thread overview]
Message-ID: <20140605155307.GD16642@pd.tnic> (raw)
In-Reply-To: <CALCETrU2TZhxOZyCvBd1nLDiU4ceiSx_Sd2bsDUCX5arOFidBg@mail.gmail.com>
On Thu, Jun 05, 2014 at 08:44:20AM -0700, Andy Lutomirski wrote:
> Are there weird contexts from which EFI calls can happen? It looks
> like the current code isn't necessarily safe in things that aren't
> normal process context but aren't interrupts either (e.g. debug traps,
> #GP, etc).
The efi-pstore thing registers as a kmsg dumper which can be run in NMI
context and efi can be called there.
> I wonder if it would make sense at some point to maintain an explicit
> stack of kernel entries. There doesn't seem to be a reliable way to
> answer the question of "what context am I in" from C code right now.
So that you can ask int ctxt = what_context_Im_in() and then that
context can go and change right underneath you. :-)
--
Regards/Gruss,
Boris.
Sent from a fat crate under my desk. Formatting is fine.
--
next prev parent reply other threads:[~2014-06-05 15:55 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 [this message]
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
2014-06-05 16:44 ` Borislav Petkov
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