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=-2.3 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=no 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 1F8F2C2BA19 for ; Sat, 18 Apr 2020 08:30:46 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [203.11.71.2]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id C1B5521D82 for ; Sat, 18 Apr 2020 08:30:45 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=c-s.fr header.i=@c-s.fr header.b="YTZxs//j" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C1B5521D82 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=c-s.fr Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from lists.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 4945kp7589zDrnD for ; Sat, 18 Apr 2020 18:30:42 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=pass (sender SPF authorized) smtp.mailfrom=c-s.fr (client-ip=93.17.236.30; helo=pegase1.c-s.fr; envelope-from=christophe.leroy@c-s.fr; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=c-s.fr Authentication-Results: lists.ozlabs.org; dkim=pass (1024-bit key; unprotected) header.d=c-s.fr header.i=@c-s.fr header.a=rsa-sha256 header.s=mail header.b=YTZxs//j; dkim-atps=neutral Received: from pegase1.c-s.fr (pegase1.c-s.fr [93.17.236.30]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 4945hv61gqzDrLZ for ; Sat, 18 Apr 2020 18:29:03 +1000 (AEST) Received: from localhost (mailhub1-int [192.168.12.234]) by localhost (Postfix) with ESMTP id 4945hp6Yqlz9tyjt; Sat, 18 Apr 2020 10:28:58 +0200 (CEST) Authentication-Results: localhost; dkim=pass reason="1024-bit key; insecure key" header.d=c-s.fr header.i=@c-s.fr header.b=YTZxs//j; dkim-adsp=pass; dkim-atps=neutral X-Virus-Scanned: Debian amavisd-new at c-s.fr Received: from pegase1.c-s.fr ([192.168.12.234]) by localhost (pegase1.c-s.fr [192.168.12.234]) (amavisd-new, port 10024) with ESMTP id vrKjyk7ZXOGw; Sat, 18 Apr 2020 10:28:58 +0200 (CEST) Received: from messagerie.si.c-s.fr (messagerie.si.c-s.fr [192.168.25.192]) by pegase1.c-s.fr (Postfix) with ESMTP id 4945hp4gl7z9tyjs; Sat, 18 Apr 2020 10:28:58 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=c-s.fr; s=mail; t=1587198538; bh=Cv9xcT2aNarUu2KPbvEQ/kk1/fAyjgfRlS/UomgKUnw=; h=To:Cc:From:Subject:Date:From; b=YTZxs//j+oCFBUF9u2rxptftD+pmTlw0wnzEXcNYQtht2O44Tbp6Ns1YwyqRAP0Sc 2S8dM8vrC2mJIfNqdD1oKeWtaIeQbWZjuxR4PI00nULDCW4KwWToyrZXiuh8DSVthv w2GZIox397+mFP0ustIKm/qP1nySpKyFqmzTWXgU= Received: from localhost (localhost [127.0.0.1]) by messagerie.si.c-s.fr (Postfix) with ESMTP id CC9068B772; Sat, 18 Apr 2020 10:28:59 +0200 (CEST) X-Virus-Scanned: amavisd-new at c-s.fr Received: from messagerie.si.c-s.fr ([127.0.0.1]) by localhost (messagerie.si.c-s.fr [127.0.0.1]) (amavisd-new, port 10023) with ESMTP id mkoibPO_wpFm; Sat, 18 Apr 2020 10:28:59 +0200 (CEST) Received: from pc16570vm.idsi0.si.c-s.fr (unknown [192.168.4.90]) by messagerie.si.c-s.fr (Postfix) with ESMTP id 4768B8B75E; Sat, 18 Apr 2020 10:28:59 +0200 (CEST) To: Segher Boessenkool From: Christophe Leroy Subject: How to use "y" constraint in GCC inline powerpc assembly ? Message-ID: <9fd93f18-652e-c301-f110-d9f07201330d@c-s.fr> Date: Sat, 18 Apr 2020 08:28:53 +0000 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.7.0 MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 8bit X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "linuxppc-dev@lists.ozlabs.org" Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Hi Segher, I'd like to use cr instead of gpr to return error condition from __get_user(). I saw in GCC doc (https://gcc.gnu.org/onlinedocs/gcc/Machine-Constraints.html) that it is possible to use "y" as constraint to refer to "Any condition register field, cr0…cr7". I tried the test below, but it fails with "error: impossible register constraint in 'asm'" How does "y" has to be used ? int test(char *p) { struct { int r:1; } res = {0}; asm("crnot %0 * 4 + eq, %0 * 4 + eq": "=&y"(res.r)); if (res.r) return -14; return 0; } Christophe