From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wm1-x342.google.com (mail-wm1-x342.google.com [IPv6:2a00:1450:4864:20::342]) by sourceware.org (Postfix) with ESMTPS id 27E093857817 for ; Fri, 11 Dec 2020 18:14:10 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 27E093857817 Received: by mail-wm1-x342.google.com with SMTP id q75so9447654wme.2 for ; Fri, 11 Dec 2020 10:14:10 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:subject:from:to:cc:references:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=gseGhqoUn7k/D+BlvubDEhNC27IIWjf8fJTqutAq8cM=; b=biVJ9wDAZNIdHdNo9uPCthMO6akVuPZ449+IWANRf0s2hPzs1iVnIAaTPdLmpma7C0 1DvtCUVnTOcUs+wGNQLOhN3jCi67Skz4FfLzk9EflqNXbTDCkijmr67ELvTC8CT50sWH ql6op1euWruSWaysut+a9mLHC/e7OT7zAo5JK1dNYXKoySX6OYkT+D9JuYeLO/pZHGWs mo8+HNq/RgsnQaPpWFQ5/cmUO9jh8YT93E1dS/KS1ogRKuJG09/MztNWx6E660BBmElQ vyUE8G0BXmAM2mNdW/FFNlLcVuP4i7ffjt7Ly6Dh2OWqPJlQ0FTFwlG66cj7bGQAaHOi VCdg== X-Gm-Message-State: AOAM5331N4EiiGsVULaDuxUBFg+suTtfUpEBnD3ewUVtcf0xcB2co5Mr KawwlwgTpzXZogSydPzB5vc= X-Google-Smtp-Source: ABdhPJzTb3VVTlnfrihA56T0Gc4uDl2lZjWBr4MFImHr+mg/zMLtg75Gl2+H8IVD7arRaequCVbw0w== X-Received: by 2002:a1c:67c5:: with SMTP id b188mr15110759wmc.147.1607710449172; Fri, 11 Dec 2020 10:14:09 -0800 (PST) Received: from [192.168.1.143] ([170.253.51.130]) by smtp.gmail.com with ESMTPSA id z17sm15455966wrh.88.2020.12.11.10.14.08 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 11 Dec 2020 10:14:08 -0800 (PST) Subject: Re: cacheflush.2 From: "Alejandro Colomar (man-pages)" To: Heinrich Schuchardt , "Michael Kerrisk (man-pages)" Cc: linux-man@vger.kernel.org, gcc@gcc.gnu.org, cfe-users@lists.llvm.org, Dave Martin References: <794cf0d1-d528-4b5a-3ce0-b1b5f588dc6d@gmx.de> <5257a883-29f0-6eaa-5708-d1f47356a57a@gmx.de> <90152ea6-f2eb-b08f-7269-f8266ffb15d1@gmail.com> Message-ID: Date: Fri, 11 Dec 2020 19:14:07 +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: <90152ea6-f2eb-b08f-7269-f8266ffb15d1@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-3.2 required=5.0 tests=BAYES_00, BODY_8BITS, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, FREEMAIL_FROM, KAM_NUMSUBJECT, KAM_SHORT, NICE_REPLY_A, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=no autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: gcc@gcc.gnu.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Gcc mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Fri, 11 Dec 2020 18:14:11 -0000 It looks like GCC recently moved from 'char *' to 'void *'. This SO question[1] (4 years ago) quotes the GCC docs and they had 'char *'. Maybe Clang hasn't noticed the change. I'll report a bug. [1]: https://stackoverflow.com/q/35741814/6872717 On 12/9/20 8:15 PM, Alejandro Colomar (man-pages) wrote: > 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; https://www.kernel.org/doc/man-pages/ http://www.alejandro-colomar.es