From: Borislav Petkov <bp@alien8.de>
To: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>,
"H. Peter Anvin" <hpa@linux.intel.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
X86 ML <x86@kernel.org>
Subject: Re: STI architectural question (and lretq -- I'm not even kidding)
Date: Wed, 23 Jul 2014 11:40:38 +0200 [thread overview]
Message-ID: <20140723094038.GA23102@pd.tnic> (raw)
In-Reply-To: <CA+55aFyefnFjmOs-QZhFn68-6+tWO30VqU6ipP6BzAra=xOaFg@mail.gmail.com>
On Tue, Jul 22, 2014 at 06:03:35PM -0700, Linus Torvalds wrote:
> So I'm afraid that "sti; lret" is not guaranteed to be architecturally
> NMI-safe. But it *might* be safe on certain micro-architectures, and
> maybe somebody inside Intel or AMD can give us a hint about when it is
> safe and when it isn't.
>From AMD's APM, STI section:
"Sets the interrupt flag (IF) in the rFLAGS register to 1, thereby
allowing external interrupts received on the INTR input. Interrupts
received on the non-maskable interrupt (NMI) input are not affected by
this instruction."
--
Regards/Gruss,
Boris.
Sent from a fat crate under my desk. Formatting is fine.
--
next prev parent reply other threads:[~2014-07-23 9:40 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-23 0:10 STI architectural question (and lretq -- I'm not even kidding) Andy Lutomirski
2014-07-23 1:03 ` Linus Torvalds
2014-07-23 1:33 ` Andy Lutomirski
2014-07-23 10:49 ` Borislav Petkov
2014-07-23 15:12 ` Andy Lutomirski
2014-07-23 15:23 ` Borislav Petkov
2014-07-23 9:40 ` Borislav Petkov [this message]
2014-07-23 21:18 ` Andi Kleen
2014-07-23 21:52 ` Andy Lutomirski
2014-07-23 23:10 ` Andi Kleen
2014-07-24 22:15 ` H. Peter Anvin
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