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=-9.2 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING, NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 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 A4980C4361B for ; Wed, 9 Dec 2020 19:16:09 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6186223AAC for ; Wed, 9 Dec 2020 19:16:09 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387521AbgLITQJ (ORCPT ); Wed, 9 Dec 2020 14:16:09 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52512 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387426AbgLITQB (ORCPT ); Wed, 9 Dec 2020 14:16:01 -0500 Received: from mail-wm1-x341.google.com (mail-wm1-x341.google.com [IPv6:2a00:1450:4864:20::341]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2976BC0613D6 for ; Wed, 9 Dec 2020 11:15:21 -0800 (PST) Received: by mail-wm1-x341.google.com with SMTP id x22so2505370wmc.5 for ; Wed, 09 Dec 2020 11:15:21 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=subject:to:cc:references:from:message-id:date:user-agent :mime-version:in-reply-to:content-language:content-transfer-encoding; bh=1rZt/k3t9CzXf4RKhZkrfsXMIKx82mw0UDClNj3a1sc=; b=PaflzcjsLdj8g0xw9ngvZJg8jp2mjX4hkeVYyd5yz+Ps/QLe8Bq5VuZi5kHZu7N2xb q5PICbWjmQQ1HVEKNJQwPECXp5QGrQZYJjTZQM0CZH1JtnNrijrqlp8Zud20aur16iXL 34zPuVl5l7Hk1ijT7bKg7YKiTFe15QCg4wFIX6wn+ePoS3CdlAWCr5FylPRQHZgUgZ4Z W+P9O8lK9LxxezQoBL9fXH7e1jbzBEf96rXtVUZDAS+MaOVCeCXxgqMc850iBzt7eAG6 KgDelvHCve3aDO4TG9NnRUVVndDBYuNVTDOf95otJRFOzeuyrcHnFXkcKBAJVMvNS92F vm6g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:to:cc:references:from:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=1rZt/k3t9CzXf4RKhZkrfsXMIKx82mw0UDClNj3a1sc=; b=mJbXufHcJGgm07QNgUD/O8eskpKXQdhPtIBMUw/7d3LP4Yg40spDWY5pl/fH/eH0l3 SM8k8kmiKPzBh/DX3aLc/SSjkhbHkyDuRgDJJgKlFTZBKG5C7vhShr2YfnbuWN7okD5H 8ZU4vWDMs7vmISj+yELUI7Jz2SFQZIYIW0NK4JZLosSBvFP0iVSY2bGzFnu3yKD3UIzt WTp+XcKS/e/Ym/jlMya0/snXPRh4fn1Ejg0+CIhV3HswqKf1hLHs4BgREEoQ43L129oD S5gIacwhAy3+oSlMylsVS6XVWrv3oZ8UYCS2VqraMXyACiU/wLBwvcIeBx2W0kI8IJzV dnGQ== X-Gm-Message-State: AOAM530XxAkqJZMZxrj7G3DpvahhEeg4D9QT8dq3Gt6EKh05PPb1MDX0 Lh4f6ic2TG8a0bIWvwrwm7U= X-Google-Smtp-Source: ABdhPJw6ILk2qBb3ziNNLB0at17WJU4kbR1Gg7f558vkUcXkUTaSUgJ+bj6gtBwwMR7a1ZfFUwQ/Eg== X-Received: by 2002:a7b:c157:: with SMTP id z23mr4312713wmi.35.1607541319960; Wed, 09 Dec 2020 11:15:19 -0800 (PST) Received: from [192.168.1.143] ([170.253.51.130]) by smtp.gmail.com with ESMTPSA id u66sm5542098wmg.30.2020.12.09.11.15.18 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 09 Dec 2020 11:15:19 -0800 (PST) Subject: Re: cacheflush.2 To: Heinrich Schuchardt , "Michael Kerrisk (man-pages)" Cc: linux-man@vger.kernel.org, gcc@gcc.gnu.org, cfe-users@lists.llvm.org References: <794cf0d1-d528-4b5a-3ce0-b1b5f588dc6d@gmx.de> <5257a883-29f0-6eaa-5708-d1f47356a57a@gmx.de> From: "Alejandro Colomar (man-pages)" Message-ID: <90152ea6-f2eb-b08f-7269-f8266ffb15d1@gmail.com> Date: Wed, 9 Dec 2020 20:15:18 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.5.1 MIME-Version: 1.0 In-Reply-To: <5257a883-29f0-6eaa-5708-d1f47356a57a@gmx.de> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-man@vger.kernel.org Hi Heinrich, It looks like a bug (or at least an undocumented divergence from GCC) in Clang/LLVM. Or I couldn't find the documentation for it. Clang uses 'char *': https://github.com/llvm/llvm-project/blob/7faf62a80bfc3a9dfe34133681fcc31f8e8d658b/clang/include/clang/Basic/Builtins.def#L583 GCC uses 'void *': https://gcc.gnu.org/onlinedocs/gcc/Other-Builtins.html I CCd Clang and GCC lists; maybe they know about that divergence. Cheers, Alex On 12/9/20 7:48 PM, Heinrich Schuchardt wrote: > On 12/9/20 7:34 PM, Alejandro Colomar (man-pages) wrote: >> Hi Heinrich & Michael, >> >> What about the following?: >> >> [ >> NOTES >>         GCC provides a similar function, which may be useful on  archi‐ >>         tectures that lack this system call: >> >>             void __builtin___clear_cache(void *begin, void *end); >> ] > > I just checked building with Clang/LLVM. There the arguments are of type > (char *). See the following error output: > > +arch/sandbox/cpu/cache.c:19:26: error: passing 'uint8_t *' (aka > 'unsigned char *') to parameter of type 'char *' converts between > pointers to integer types with different sign [-Werror,-Wpointer-sign] > +        __builtin___clear_cache(state->ram_buf, > +                                ^~~~~~~~~~~~~~ > +arch/sandbox/cpu/cache.c:20:12: error: passing 'uint8_t *' (aka > 'unsigned char *') to parameter of type 'char *' converts between > pointers to integer types with different sign [-Werror,-Wpointer-sign] > +                                state->ram_buf + state->ram_size); > +                                ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > Best regards > > Heinrich > >> >> Cheers, >> >> Alex >> >> On 12/9/20 7:04 PM, Heinrich Schuchardt wrote: >>> Hello Michael, >>> >>> function cacheflush() does not exist on many architectures. >>> >>> It would have saved me a lot of time if the man-page had referenced >>> GCC's >>> >>> void __builtin___clear_cache(void *begin, void *end) >>> >>> Maybe you can add it to NOTES. >>> >>> Best regards >>> >>> heirnich >> > -- Alejandro Colomar Linux man-pages comaintainer; http://www.kernel.org/doc/man-pages/ http://www.alejandro-colomar.es