Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757861AbaGWJkm (ORCPT ); Wed, 23 Jul 2014 05:40:42 -0400 Received: from mail.skyhub.de ([78.46.96.112]:38101 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757745AbaGWJkl (ORCPT ); Wed, 23 Jul 2014 05:40:41 -0400 Date: Wed, 23 Jul 2014 11:40:38 +0200 From: Borislav Petkov To: Linus Torvalds Cc: Andy Lutomirski , "H. Peter Anvin" , "linux-kernel@vger.kernel.org" , X86 ML Subject: Re: STI architectural question (and lretq -- I'm not even kidding) Message-ID: <20140723094038.GA23102@pd.tnic> References: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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. -- -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/