From mboxrd@z Thu Jan 1 00:00:00 1970 From: "H. Peter Anvin" Subject: Re: [PATCH V2] sparse: Allow override of sizeof(bool) warning Date: Thu, 27 Feb 2014 07:10:25 -0800 Message-ID: References: <530E6F76.1070605@zytor.com> <1393462087.24588.50.camel@joe-AO722> <530E8C2E.7080307@zytor.com> <1393466619.24588.65.camel@joe-AO722> <20140227022857.GC23659@thin> <1393469594.24588.71.camel@joe-AO722> <20140227025845.GA25145@thin> <530EB103.5070406@zytor.com> <1393472326.24588.82.camel@joe-AO722> <60797a1a-1a83-468e-9629-abf4e8712d65@email.android.com> <20140227082529.GA18210@pd.tnic> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Return-path: Received: from terminus.zytor.com ([198.137.202.10]:55990 "EHLO mail.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751192AbaB0PL0 (ORCPT ); Thu, 27 Feb 2014 10:11:26 -0500 In-Reply-To: <20140227082529.GA18210@pd.tnic> Sender: linux-sparse-owner@vger.kernel.org List-Id: linux-sparse@vger.kernel.org To: Borislav Petkov Cc: Joe Perches , Ben Pfaff , Christopher Li , Josh Triplett , linux-sparse@vger.kernel.org, Linux Kernel Mailing List Keep in mind, too, that for the kernel we don't care about the full C standard but a subset. We rely on extrastandard behavior all over the place. For all ABIs supported by the kernel, sizeof(_Book) == 1 and so everything is sane. On February 27, 2014 12:25:29 AM PST, Borislav Petkov wrote: >On Wed, Feb 26, 2014 at 07:42:37PM -0800, H. Peter Anvin wrote: >> sizeof(_Bool), like for many other types, is ABI-dependent, but that >> doesn't mean it is illegitimate. >> >> I don't think C99 says that it is invalid (which means C99 doesn't >> permit is to be a packed bitmap.) > >Ok, but what can be said about the __pcpu_size_call() use case where we >do sizeof(bool)? We have there accessors for sizes 1,2,4 and 8. Can we >simply assume that the ABI will give us a size of bool which is one of >those? > >What if sizeof(bool) is 3? > >Or, are we saying that sizeof(bool) will always be of some natural, >native size like byte, short, int or long so we're good there? > >Thanks. -- Sent from my mobile phone. Please pardon brevity and lack of formatting.