From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-14.0 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 90AB2C433DB for ; Mon, 22 Mar 2021 20:36:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5848261992 for ; Mon, 22 Mar 2021 20:36:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231703AbhCVUgT (ORCPT ); Mon, 22 Mar 2021 16:36:19 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43808 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230377AbhCVUfb (ORCPT ); Mon, 22 Mar 2021 16:35:31 -0400 Received: from mail-ed1-x52f.google.com (mail-ed1-x52f.google.com [IPv6:2a00:1450:4864:20::52f]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 29D09C061574 for ; Mon, 22 Mar 2021 13:35:30 -0700 (PDT) Received: by mail-ed1-x52f.google.com with SMTP id bx7so20965859edb.12 for ; Mon, 22 Mar 2021 13:35:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:date:from:to:cc:subject:message-id:references:mime-version :content-disposition:content-transfer-encoding:in-reply-to; bh=KU4nfRvbfNbUHO2h9TXLz9JlUbED5OGOV5WQblopDQo=; b=bSS/BFvjqUh4ve7QgLOGNgSV7lHkbjP/3jU+f0FgTH8iN5jHMtDVAh3degFW0znI3p dOahxo2ijK3WL05Zq8M8HaTJCN4nUR+Z99+MmedHZzg+b4bsJb6Ql+rTVtuNS31ZuQVh u0evnJF+rQj5c76/e0GaZQIOnoeuUTKFNdf1mSx5GPHVlGBRz1UA2YN83njqyT8fvoBT v/6T2jOpjbpG/tfN3MbAt+v6qaEfcIxBZUo8vrveX1qS4QGgK5ch07lGHwsbjZRGwDSf T3GvQO6lx9YC83pFn14hwVdPY98JCLVdUKKbBL/HyxwrHY2wMY48EyeTdMyVwIvlOPUK t12g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:date:from:to:cc:subject:message-id :references:mime-version:content-disposition :content-transfer-encoding:in-reply-to; bh=KU4nfRvbfNbUHO2h9TXLz9JlUbED5OGOV5WQblopDQo=; b=HlB39UbxzqrXRMTr9tMXH1hukV8rKpqDS0N4kuYItOwvUk2jRSGgKHykoiyErKJeKX R8NVaoen3gjY/YLbKIL3h4E8A14ps4usUEWRQPxBHlKi77xfNQoVk5KC8ENd2ObMtMVg HikNDtKQxO4EApZe+XpdpCdW1L/cG7J92QD/ce7CxwyaLPtJQVghl5oFUu7NsqxIBoNo QH/OI8Lxe+hH5UaqIzhZtvkLaLJexegK0oSf6M8rewj+2s5PSDqOKP1xmpyfc9HtoAlf dZHZ8K4X6MQSSmWSJb4oX4BhyeP0AHTAM6g//5jcSQBEAe/sOovgWw6P6/YejVC6TmvB 8K/w== X-Gm-Message-State: AOAM533fjsqjnCBlJ8yYfVjbnR1jMGCQPmAVp5JeT16MgpNTp+mgAr3m AQGgNtFp0TkEOHAfwaG5w85fCt84QzQ= X-Google-Smtp-Source: ABdhPJz9HKNxk90KYQN/7EX0UqXQeXg4rdNg+q5uDAh4XwlSqT3XDEWUdZHamCupqp948j8yNVDwqw== X-Received: by 2002:aa7:c4d1:: with SMTP id p17mr1381110edr.387.1616445328908; Mon, 22 Mar 2021 13:35:28 -0700 (PDT) Received: from gmail.com (54033286.catv.pool.telekom.hu. [84.3.50.134]) by smtp.gmail.com with ESMTPSA id p24sm11880965edt.5.2021.03.22.13.35.27 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 22 Mar 2021 13:35:28 -0700 (PDT) Sender: Ingo Molnar Date: Mon, 22 Mar 2021 21:35:26 +0100 From: Ingo Molnar To: Arnd Bergmann Cc: Bill Metzenthen , Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, Arnd Bergmann , "H. Peter Anvin" , "Gustavo A. R. Silva" , linux-kernel@vger.kernel.org Subject: Re: [PATCH] x86: math-emu: Fix function cast warning Message-ID: <20210322203526.GB1955909@gmail.com> References: <20210322170610.1823153-1-arnd@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20210322170610.1823153-1-arnd@kernel.org> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Arnd Bergmann wrote: > From: Arnd Bergmann > > Building with 'make W=1', gcc points out that casting between > incompatible function types can be dangerous: > > arch/x86/math-emu/fpu_trig.c:1638:60: error: cast between incompatible function types from ‘int (*)(FPU_REG *, u_char)’ {aka ‘int (*)(struct fpu__reg *, unsigned char)’} to ‘void (*)(FPU_REG *, u_char)’ {aka ‘void (*)(struct fpu__reg *, unsigned char)’} [-Werror=cast-function-type] > 1638 | fprem, fyl2xp1, fsqrt_, fsincos, frndint_, fscale, (FUNC_ST0) fsin, fcos > | ^ > > This one seems harmless, but it is easy enough to work around it by > adding an intermediate function that adjusts the return type. > > Signed-off-by: Arnd Bergmann > --- > arch/x86/math-emu/fpu_trig.c | 11 ++++++++--- > 1 file changed, 8 insertions(+), 3 deletions(-) > > diff --git a/arch/x86/math-emu/fpu_trig.c b/arch/x86/math-emu/fpu_trig.c > index 4a9887851ad8..aebfdb244cb4 100644 > --- a/arch/x86/math-emu/fpu_trig.c > +++ b/arch/x86/math-emu/fpu_trig.c > @@ -547,7 +547,7 @@ static void frndint_(FPU_REG *st0_ptr, u_char st0_tag) > single_arg_error(st0_ptr, st0_tag); > } > > -static int fsin(FPU_REG *st0_ptr, u_char tag) > +static int do_fsin(FPU_REG *st0_ptr, u_char tag) > { > u_char arg_sign = getsign(st0_ptr); > > @@ -608,6 +608,11 @@ static int fsin(FPU_REG *st0_ptr, u_char tag) > } > } > > +static void fsin(FPU_REG *st0_ptr, u_char tag) > +{ > + fsin(st0_ptr, tag); > +} > + > static int f_cos(FPU_REG *st0_ptr, u_char tag) > { > u_char st0_sign; The existing nomenclature in that code is: static int f_cos(FPU_REG *st0_ptr, u_char tag) static void fcos(FPU_REG *st0_ptr, u_char st0_tag) So I'd suggest naming the variant with a return value f_sin(). Thanks, Ingo