From mboxrd@z Thu Jan 1 00:00:00 1970 From: Len Brown Subject: Re: linux-next: build failure after merge of the tip tree Date: Sun, 19 Jan 2014 23:45:43 -0500 Message-ID: References: <20140116145829.5e4fcab103b1c5c77501ee77@canb.auug.org.au> <20140116121955.GQ31570@twins.programming.kicks-ass.net> <20140117074628.88698f59939c9002b7c12968@canb.auug.org.au> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Return-path: Received: from mail-wi0-f175.google.com ([209.85.212.175]:47984 "EHLO mail-wi0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752367AbaATEpp (ORCPT ); Sun, 19 Jan 2014 23:45:45 -0500 In-Reply-To: <20140117074628.88698f59939c9002b7c12968@canb.auug.org.au> Sender: linux-next-owner@vger.kernel.org List-ID: To: Stephen Rothwell Cc: Peter Zijlstra , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , linux-next@vger.kernel.org, "linux-kernel@vger.kernel.org" +static void mwait_idle(void) +{ + mwait_idle_with_hints(0, 0); +} + The reason the patch above will crash Core2 machines is because core2 machines don't support mwait_idle_with_hints(). The calling sequence for old and new MWAIT instructions is different. The former must be invoked with interrupts enabled, and the later can be invoked with interrupts disabled, which is a feature that Linux takes advantage of. thanks, -Len