From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-qv1-xf41.google.com (mail-qv1-xf41.google.com [IPv6:2607:f8b0:4864:20::f41]) by sourceware.org (Postfix) with ESMTPS id 479353957483 for ; Thu, 23 Apr 2020 21:35:03 +0000 (GMT) DMARC-Filter: OpenDMARC Filter v1.3.2 sourceware.org 479353957483 Received: by mail-qv1-xf41.google.com with SMTP id 59so1595417qva.13 for ; Thu, 23 Apr 2020 14:35:03 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:to:cc:references:from:autocrypt:subject :message-id:date:user-agent:mime-version:in-reply-to :content-language:content-transfer-encoding; bh=qenYTEjUwN71cuSB7HNZ3ovkngBXG6gcnNe2J4l/UTA=; b=nFlazqRXbI1RJqKbt6SkyuyehZaIV8XW2HQlz0S3aWUQV/9A3Ynu8bwRzcPOmZRUkW nO8Ia+YtIrUNr7uFNfXa9faB456Abk4x896XWyBjaFe+ubV/UrkjWw5pQDtJywqpu8mz DtOw/9D4aLRi++iV7vb7vgha7pOYMJM2aiAC45m7DpkjY/jR6eyCmEP3yWDfV/9VCm4w +TPyPCOr/aoZ31PhRtQzFbgXcdMvFUDBvcG9V0hZZAZQKPtzE6ueKg4xZnLab2Z7pbZ2 qf6Omv5Kxz46b7z1NnFzsb+KKX1ygZV4CLm1E+IhPROfarYS/0uorlleK1oIwrZ7LS39 15fg== X-Gm-Message-State: AGi0Puaw/rM8XyrYVqKtuC9dOccQVwa/g2a+9NXq9Zik2ICvBKP8GKgl NEWKOORVVPhxA28v+Q5387XbCqol9fOHzA== X-Google-Smtp-Source: APiQypLu7Gyv5eRSXZQQ3lvVg+NS6jJvSznb81S2Iw+Rfq2jurAxrWHa2t7r+g+4NoueKGJz+lxanw== X-Received: by 2002:a0c:b78e:: with SMTP id l14mr6395475qve.4.1587677702529; Thu, 23 Apr 2020 14:35:02 -0700 (PDT) Received: from [192.168.1.4] ([177.194.48.209]) by smtp.googlemail.com with ESMTPSA id b3sm2488028qtp.12.2020.04.23.14.35.01 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 23 Apr 2020 14:35:01 -0700 (PDT) To: Joseph Myers Cc: libc-alpha@sourceware.org References: <20200413175117.170042-1-hjl.tools@gmail.com> <20200413175117.170042-2-hjl.tools@gmail.com> <878sinls2q.fsf@mid.deneb.enyo.de> <65245414-5e9e-7682-12d6-84df7d970646@linaro.org> From: Adhemerval Zanella Autocrypt: addr=adhemerval.zanella@linaro.org; prefer-encrypt=mutual; keydata= xsFNBFcVGkoBEADiQU2x/cBBmAVf5C2d1xgz6zCnlCefbqaflUBw4hB/bEME40QsrVzWZ5Nq 8kxkEczZzAOKkkvv4pRVLlLn/zDtFXhlcvQRJ3yFMGqzBjofucOrmdYkOGo0uCaoJKPT186L NWp53SACXguFJpnw4ODI64ziInzXQs/rUJqrFoVIlrPDmNv/LUv1OVPKz20ETjgfpg8MNwG6 iMizMefCl+RbtXbIEZ3TE/IaDT/jcOirjv96lBKrc/pAL0h/O71Kwbbp43fimW80GhjiaN2y WGByepnkAVP7FyNarhdDpJhoDmUk9yfwNuIuESaCQtfd3vgKKuo6grcKZ8bHy7IXX1XJj2X/ BgRVhVgMHAnDPFIkXtP+SiarkUaLjGzCz7XkUn4XAGDskBNfbizFqYUQCaL2FdbW3DeZqNIa nSzKAZK7Dm9+0VVSRZXP89w71Y7JUV56xL/PlOE+YKKFdEw+gQjQi0e+DZILAtFjJLoCrkEX w4LluMhYX/X8XP6/C3xW0yOZhvHYyn72sV4yJ1uyc/qz3OY32CRy+bwPzAMAkhdwcORA3JPb kPTlimhQqVgvca8m+MQ/JFZ6D+K7QPyvEv7bQ7M+IzFmTkOCwCJ3xqOD6GjX3aphk8Sr0dq3 4Awlf5xFDAG8dn8Uuutb7naGBd/fEv6t8dfkNyzj6yvc4jpVxwARAQABzUlBZGhlbWVydmFs IFphbmVsbGEgTmV0dG8gKExpbmFybyBWUE4gS2V5KSA8YWRoZW1lcnZhbC56YW5lbGxhQGxp bmFyby5vcmc+wsF3BBMBCAAhBQJXFRpKAhsDBQsJCAcDBRUKCQgLBRYCAwEAAh4BAheAAAoJ EKqx7BSnlIjv0e8P/1YOYoNkvJ+AJcNUaM5a2SA9oAKjSJ/M/EN4Id5Ow41ZJS4lUA0apSXW NjQg3VeVc2RiHab2LIB4MxdJhaWTuzfLkYnBeoy4u6njYcaoSwf3g9dSsvsl3mhtuzm6aXFH /Qsauav77enJh99tI4T+58rp0EuLhDsQbnBic/ukYNv7sQV8dy9KxA54yLnYUFqH6pfH8Lly sTVAMyi5Fg5O5/hVV+Z0Kpr+ZocC1YFJkTsNLAW5EIYSP9ftniqaVsim7MNmodv/zqK0IyDB GLLH1kjhvb5+6ySGlWbMTomt/or/uvMgulz0bRS+LUyOmlfXDdT+t38VPKBBVwFMarNuREU2 69M3a3jdTfScboDd2ck1u7l+QbaGoHZQ8ZNUrzgObltjohiIsazqkgYDQzXIMrD9H19E+8fw kCNUlXxjEgH/Kg8DlpoYJXSJCX0fjMWfXywL6ZXc2xyG/hbl5hvsLNmqDpLpc1CfKcA0BkK+ k8R57fr91mTCppSwwKJYO9T+8J+o4ho/CJnK/jBy1pWKMYJPvvrpdBCWq3MfzVpXYdahRKHI ypk8m4QlRlbOXWJ3TDd/SKNfSSrWgwRSg7XCjSlR7PNzNFXTULLB34sZhjrN6Q8NQZsZnMNs TX8nlGOVrKolnQPjKCLwCyu8PhllU8OwbSMKskcD1PSkG6h3r0AqzsFNBFcVGkoBEACgAdbR Ck+fsfOVwT8zowMiL3l9a2DP3Eeak23ifdZG+8Avb/SImpv0UMSbRfnw/N81IWwlbjkjbGTu oT37iZHLRwYUFmA8fZX0wNDNKQUUTjN6XalJmvhdz9l71H3WnE0wneEM5ahu5V1L1utUWTyh VUwzX1lwJeV3vyrNgI1kYOaeuNVvq7npNR6t6XxEpqPsNc6O77I12XELic2+36YibyqlTJIQ V1SZEbIy26AbC2zH9WqaKyGyQnr/IPbTJ2Lv0dM3RaXoVf+CeK7gB2B+w1hZummD21c1Laua +VIMPCUQ+EM8W9EtX+0iJXxI+wsztLT6vltQcm+5Q7tY+HFUucizJkAOAz98YFucwKefbkTp eKvCfCwiM1bGatZEFFKIlvJ2QNMQNiUrqJBlW9nZp/k7pbG3oStOjvawD9ZbP9e0fnlWJIsj 6c7pX354Yi7kxIk/6gREidHLLqEb/otuwt1aoMPg97iUgDV5mlNef77lWE8vxmlY0FBWIXuZ yv0XYxf1WF6dRizwFFbxvUZzIJp3spAao7jLsQj1DbD2s5+S1BW09A0mI/1DjB6EhNN+4bDB SJCOv/ReK3tFJXuj/HbyDrOdoMt8aIFbe7YFLEExHpSk+HgN05Lg5TyTro8oW7TSMTk+8a5M kzaH4UGXTTBDP/g5cfL3RFPl79ubXwARAQABwsFfBBgBCAAJBQJXFRpKAhsMAAoJEKqx7BSn lIjvI/8P/jg0jl4Tbvg3B5kT6PxJOXHYu9OoyaHLcay6Cd+ZrOd1VQQCbOcgLFbf4Yr+rE9l mYsY67AUgq2QKmVVbn9pjvGsEaz8UmfDnz5epUhDxC6yRRvY4hreMXZhPZ1pbMa6A0a/WOSt AgFj5V6Z4dXGTM/lNManr0HjXxbUYv2WfbNt3/07Db9T+GZkpUotC6iknsTA4rJi6u2ls0W9 1UIvW4o01vb4nZRCj4rni0g6eWoQCGoVDk/xFfy7ZliR5B+3Z3EWRJcQskip/QAHjbLa3pml xAZ484fVxgeESOoaeC9TiBIp0NfH8akWOI0HpBCiBD5xaCTvR7ujUWMvhsX2n881r/hNlR9g fcE6q00qHSPAEgGr1bnFv74/1vbKtjeXLCcRKk3Ulw0bY1OoDxWQr86T2fZGJ/HIZuVVBf3+ gaYJF92GXFynHnea14nFFuFgOni0Mi1zDxYH/8yGGBXvo14KWd8JOW0NJPaCDFJkdS5hu0VY 7vJwKcyHJGxsCLU+Et0mryX8qZwqibJIzu7kUJQdQDljbRPDFd/xmGUFCQiQAncSilYOcxNU EMVCXPAQTteqkvA+gNqSaK1NM9tY0eQ4iJpo+aoX8HAcn4sZzt2pfUB9vQMTBJ2d4+m/qO6+ cFTAceXmIoFsN8+gFN3i8Is3u12u8xGudcBPvpoy4OoG Subject: Re: V2 [PATCH 1/2] Add SYSCALL_ULONG_ARG_[12] to pass long to syscall [BZ #25810] Message-ID: <864e3814-e170-ba00-cb3e-5647c9379d99@linaro.org> Date: Thu, 23 Apr 2020 18:34:59 -0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-GB Content-Transfer-Encoding: 8bit X-Spam-Status: No, score=-12.7 required=5.0 tests=BAYES_00, DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, DKIM_VALID_EF, RCVD_IN_DNSWL_NONE, SPF_HELO_NONE, SPF_PASS, TXREP autolearn=ham autolearn_force=no version=3.4.2 X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on server2.sourceware.org X-BeenThere: libc-alpha@sourceware.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Libc-alpha mailing list List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 23 Apr 2020 21:35:04 -0000 On 22/04/2020 19:01, Joseph Myers wrote: > On Wed, 22 Apr 2020, Adhemerval Zanella via Libc-alpha wrote: > >>> I must say that I find this really, really ugly. We should rewrite >>> this in Python as soon as possible (in a separate patch). >> >> And I think we should make long term gold to just get rid of this >> assembly macro and focus on automatic generation to a C code file >> as well. > > There are a couple of possible improvements in this area that might be in > tension here: > > * Simplifying how the syscall arguments are specified. The reason there > are so many different letters is not because of anything relevant to > assembly code generation now, it's because of the old support for bounded > pointers (removed from GCC in 2002, actual substantive uses in the glibc > syscall generation code removed in > ). > > * Generating debug info for the automatically generated syscall > implementations. For that, the C code should have actual meaningful > argument types, not just a sequence of integers that has the right ABI > (but may not even have the right number of arguments, in cases where a > 64-bit argument uses two letters for syscall arguments in the 32-bit > syscalls.list files). > > What this suggests to me is that automatically-generated C code should get > actual argument types from the header files in some way, and in the cases > where header file information isn't sufficient (including syscalls not > declared in header files or with different arguments to the public C > function, etc.), using some sort of internal header to give the types > might be better than having complicated encodings in syscalls.list. Maybe > syscalls.list doesn't need much more information than the conventions for > return value / error handling and the *number* of arguments, if types can > be extracted from C headers. My initial approach would be to extend the syscall argument definition on syscall file description (syscalls.list) with all the required information to synthesize the C implementation. It increases the verbose required in the argument description, but I think it would simpler than try infer from the header itself (which would require to parse the it and the this information). Something like, using wordsize-64 fstatfs syscalls.list entry: fstatfs fstatfs [sys/statfs.h] [const char *, struct statfs64 *] [fstatfs64:w, __fstatfs64:w] which would translate to: #define fstatfs64 __redirect_fstatfs64 #define __fstatfs64 __redirect___fstatfs64 #include #undef fstatfs64 #undef __fstatfs64 int __fstatfs (int arg1, struct statfs *arg2) { return INLINE_SYSCALL_CALL (fstatfs, arg1, arg2); } weak_alias (__fstatfs, fstatfs) weak_alias (__fstatfs, __fstatfs64) weak_alias (__fstatfs, fstatfs64) The alias would require some pre-defined logic to handle the LFS alias for __OFF_T_MATCHES_OFF64_T (and I am not sure if this example would be better handled in a C implementation in fact), to handle internal hidden alias, and version.