From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-wr1-x42a.google.com (mail-wr1-x42a.google.com [IPv6:2a00:1450:4864:20::42a]) by sourceware.org (Postfix) with ESMTPS id 6FB353858010 for ; Fri, 18 Dec 2020 10:42:51 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 6FB353858010 Received: by mail-wr1-x42a.google.com with SMTP id a12so1612385wrv.8 for ; Fri, 18 Dec 2020 02:42:51 -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:references:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=C7Pircx+KXcK6zkuz9WQ0wrPyIlrxZ6ddDM/TlPxGas=; b=jn82dksvEQdBWEtV8tqsTPxlRlFA4V8VOnkyCwtNHZ5tD+5UlCMUq+vkZ0Yz4jWNT8 eNKDXQHztbxCrwilSZtahbUmMWJinGSIa5td3kdB0adhvyE9tpJ2Sgyql0x5Ci+iOTWU BUnlTjthwxw1dGdKwXYrfZE68e4YNDLSOesNkZOZEwgoOAelPZO1LoK0/Hlrqp8DarPd IO61jsO2NbSnSZ2BwBZVAnPEV5LTuhgzwOQcZocNDaSdFzFr0IIveFT0hDksVV9ElF6S pwGtoFFvvl3F0R2ekiItc/LHSRuMAyqWjOiohEKWoM98onu1akoLTrDmiEzwOOFHUpRu HAGw== X-Gm-Message-State: AOAM5315CkfKjY8TSUzDzcZmrpllyw4rOHj72NJw76fbwbh3QWUjBORt C0aPb84xYfekSQ6Riqpc4v0= X-Google-Smtp-Source: ABdhPJyjV+QVp2QSRGFS6ypbqNGlIZ8MAe4zHVSHAOdYIn0+T4SVIPFbm9cZcN+C6Ure2qbh+rRmLg== X-Received: by 2002:adf:e990:: with SMTP id h16mr3748171wrm.307.1608288170180; Fri, 18 Dec 2020 02:42:50 -0800 (PST) Received: from [192.168.1.143] ([170.253.51.130]) by smtp.gmail.com with ESMTPSA id h4sm12430627wrt.65.2020.12.18.02.42.48 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 18 Dec 2020 02:42:49 -0800 (PST) Subject: Ping: cacheflush.2 From: "Alejandro Colomar (man-pages)" To: Martin Sebor , Heinrich Schuchardt , "Michael Kerrisk (man-pages)" , gcc@gcc.gnu.org, Dave Martin , cfe-users@lists.llvm.org, linux-man@vger.kernel.org References: <794cf0d1-d528-4b5a-3ce0-b1b5f588dc6d@gmx.de> <5257a883-29f0-6eaa-5708-d1f47356a57a@gmx.de> <90152ea6-f2eb-b08f-7269-f8266ffb15d1@gmail.com> <52a37c46-3488-957c-fc50-6caca177cb3c@gmail.com> <64bd5678-4c25-668d-39b2-31c825253d1b@gmail.com> Message-ID: <6ed5bc42-1d18-e963-fecc-cc9b1bfb2a2c@gmail.com> Date: Fri, 18 Dec 2020 11:42:48 +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: <64bd5678-4c25-668d-39b2-31c825253d1b@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-2.8 required=5.0 tests=BAYES_00, BODY_8BITS, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, FREEMAIL_FROM, KAM_NUMSUBJECT, KAM_SHORT, 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, 18 Dec 2020 10:42:53 -0000 Hi Martin, I sent you an email, but I received a "delivery failure". If you're reading this from a list, could you answer, please? Thanks, Alex On 12/14/20 11:34 PM, Alejandro Colomar (man-pages) wrote: > Hello Martin, > > Thanks for the correction! > Then the prototypes that changes from 'char *' to 'void *' in r269082 > were not exposed to the user, right? > I guess then those are just internal implementation where GCC did use > 'char *'. > > Where is the actual prototype exposed to the user declared? > > Thanks, > > Alex > > P.S.: Michael, wait for a patch revision (v6). > > On 12/14/20 10:13 PM, Martin Sebor wrote: >> On 12/11/20 11:14 AM, Alejandro Colomar (man-pages) via Gcc wrote: >>> 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 *'. >> >> __builtin___clear_cache in GCC has always been declared to take >> void*.  The signature in the manual was recently corrected to match >> the implementation, i.e., from char* to void*, in r269082. >> >> Martin >> >>> 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/