From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932106AbbG1Jua (ORCPT ); Tue, 28 Jul 2015 05:50:30 -0400 Received: from mail.skyhub.de ([78.46.96.112]:53218 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932552AbbG1JuY (ORCPT ); Tue, 28 Jul 2015 05:50:24 -0400 Date: Tue, 28 Jul 2015 11:50:19 +0200 From: Borislav Petkov To: Andy Lutomirski Cc: X86 ML , linux-kernel@vger.kernel.org, Brian Gerst , Steven Rostedt , Willy Tarreau , Thomas Gleixner , Peter Zijlstra , Linus Torvalds Subject: Re: [PATCH v2 2/3] x86/entry/64: Teach idtentry to use the IRQ stack Message-ID: <20150728095019.GD1612@nazgul.tnic> References: <74421f7102368e3396a652bb7ed49afb65f07e09.1437803711.git.luto@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <74421f7102368e3396a652bb7ed49afb65f07e09.1437803711.git.luto@kernel.org> 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 Fri, Jul 24, 2015 at 10:57:05PM -0700, Andy Lutomirski wrote: > We don't specifically need IST for things like kprobes, but we do > want to avoid rare, surprising extra stack usage if a kprobe hits > with a deep stack. > > Teach idtentry to use the IRQ stack for selected entries. > > This implementation uses the IRQ stack even if we entered from user > mode. This disallows tricks like ist_begin_non_atomic. If we ever > need such a trick in one of these entries, we can rework this. For > now, let's keep it simple. > > Signed-off-by: Andy Lutomirski > --- > arch/x86/entry/entry_64.S | 14 +++++++++++++- > 1 file changed, 13 insertions(+), 1 deletion(-) Reviewed-by: Borislav Petkov -- Regards/Gruss, Boris. ECO tip #101: Trim your mails when you reply. --