Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S934074AbcDTLV7 (ORCPT ); Wed, 20 Apr 2016 07:21:59 -0400 Received: from bombadil.infradead.org ([198.137.202.9]:49493 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933617AbcDTLV6 (ORCPT ); Wed, 20 Apr 2016 07:21:58 -0400 Date: Wed, 20 Apr 2016 13:21:52 +0200 From: Peter Zijlstra To: Andy Lutomirski Cc: Dmitry Safonov , "linux-kernel@vger.kernel.org" , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , X86 ML , Robert Richter , oprofile-list@lists.sf.net, Dmitry Safonov <0x7f454c46@gmail.com> Subject: Re: [PATCH 3/4] x86/intel lbr: down with test_thread_flag(TIF_IA32) Message-ID: <20160420112152.GA3408@twins.programming.kicks-ass.net> References: <1460657414-12530-1-git-send-email-dsafonov@virtuozzo.com> <1460657414-12530-4-git-send-email-dsafonov@virtuozzo.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2012-12-30) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 839 Lines: 19 On Thu, Apr 14, 2016 at 12:29:12PM -0700, Andy Lutomirski wrote: > On Thu, Apr 14, 2016 at 11:10 AM, Dmitry Safonov wrote: > > @@ -724,7 +727,7 @@ static int branch_type(unsigned long from, unsigned long to, int abort) > > * on 64-bit systems running 32-bit apps > > */ > > #ifdef CONFIG_X86_64 > > - is64 = kernel_ip((unsigned long)addr) || !test_thread_flag(TIF_IA32); > > + is64 = kernel_ip((unsigned long)addr) || user_64bit_mode(regs); > > Peterz, looking at this some more, would it make sense to pass > user_regs and interrupt_regs (or whatever we'd call it) all the way > through to here? Urgh; again, wtf wasn't I Cc'ed to these patches? And not sure; if we never need the user regs, calling perf_get_user_regs() to set all that up seems like a massive waste of cycles.