From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752361AbcELHZu (ORCPT ); Thu, 12 May 2016 03:25:50 -0400 Received: from merlin.infradead.org ([205.233.59.134]:60559 "EHLO merlin.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751587AbcELHZt (ORCPT ); Thu, 12 May 2016 03:25:49 -0400 Date: Thu, 12 May 2016 09:25:42 +0200 From: Peter Zijlstra To: Vineet Gupta Cc: linux-perf-users@vger.kernel.org, Vince Weaver , linux-kernel@vger.kernel.org, acme@redhat.com, linux-snps-arc@lists.infradead.org, mingo@kernel.org Subject: Re: [RFC 2/2] perf/core: change errno for sampling event not supported in hardware Message-ID: <20160512072542.GM3192@twins.programming.kicks-ass.net> References: <1462786660-2900-1-git-send-email-vgupta@synopsys.com> <1462786660-2900-3-git-send-email-vgupta@synopsys.com> <5730C79F.3060307@synopsys.com> <20160511193627.GH3190@twins.programming.kicks-ass.net> <5734229B.90706@synopsys.com> <20160512064201.GL3192@twins.programming.kicks-ass.net> <573428A1.3060402@synopsys.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <573428A1.3060402@synopsys.com> 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 On Thu, May 12, 2016 at 12:24:25PM +0530, Vineet Gupta wrote: > On Thursday 12 May 2016 12:12 PM, Peter Zijlstra wrote: > >> Tried that and doesn't even compile. Reconfirms what Vince said, ENOTSUPP is not > >> > exposed to userspace (being in include/linux and not include/uapi/linux) > > Durr, so what does userspace see? > > It sees the "value" of ENOTSUPP, i.e. 524 but there is no symbolic reference to it :-) Ah.. which might be a hint that nobody is actually explicitly testing for this and we might just get away with changing the ABI. Vince, what say you; shall we try and get away with it? ;-)