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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 36ECDC33CB6 for ; Wed, 22 Jan 2020 13:24:24 +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 A73D02468F for ; Wed, 22 Jan 2020 13:24:23 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A73D02468F Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=kernel.crashing.org 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 482mMm6bD8zDqNy for ; Thu, 23 Jan 2020 00:24:20 +1100 (AEDT) Authentication-Results: lists.ozlabs.org; spf=permerror (SPF Permanent Error: Unknown mechanism found: ip:192.40.192.88/32) smtp.mailfrom=kernel.crashing.org (client-ip=63.228.1.57; helo=gate.crashing.org; envelope-from=segher@kernel.crashing.org; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=kernel.crashing.org Received: from gate.crashing.org (gate.crashing.org [63.228.1.57]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by lists.ozlabs.org (Postfix) with ESMTPS id 482mFq01qLzDqSd for ; Thu, 23 Jan 2020 00:19:10 +1100 (AEDT) Received: from gate.crashing.org (localhost.localdomain [127.0.0.1]) by gate.crashing.org (8.14.1/8.14.1) with ESMTP id 00MDIsXk010897; Wed, 22 Jan 2020 07:18:54 -0600 Received: (from segher@localhost) by gate.crashing.org (8.14.1/8.14.1/Submit) id 00MDIsPK010895; Wed, 22 Jan 2020 07:18:54 -0600 X-Authentication-Warning: gate.crashing.org: segher set sender to segher@kernel.crashing.org using -f Date: Wed, 22 Jan 2020 07:18:54 -0600 From: Segher Boessenkool To: Christophe Leroy Subject: Re: GCC bug ? Re: [PATCH v2 10/10] powerpc/32s: Implement Kernel Userspace Access Protection Message-ID: <20200122131854.GK3191@gate.crashing.org> References: <87ftqfu7j1.fsf@concordia.ellerman.id.au> <20200121195501.GJ3191@gate.crashing.org> <8501a33e-6c76-b6bd-9d8e-985313f94579@c-s.fr> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <8501a33e-6c76-b6bd-9d8e-985313f94579@c-s.fr> User-Agent: Mutt/1.4.2.3i 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: linux-kernel@vger.kernel.org, Paul Mackerras , linuxppc-dev@lists.ozlabs.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" Hi! On Wed, Jan 22, 2020 at 07:57:15AM +0100, Christophe Leroy wrote: > GCC doc also says: > > "if you use it in an inlined function and pass an argument of the > function as the argument to the built-in, GCC never returns 1 when you > call the inline function with a string constant" > > Does GCC considers (void*)0 as a string constant ? No, because it isn't (it's a pointer, not an array of characters). Segher 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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 EC514C2D0DB for ; Wed, 22 Jan 2020 13:19:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C9D452071E for ; Wed, 22 Jan 2020 13:19:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729683AbgAVNT3 (ORCPT ); Wed, 22 Jan 2020 08:19:29 -0500 Received: from gate.crashing.org ([63.228.1.57]:38045 "EHLO gate.crashing.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728665AbgAVNTY (ORCPT ); Wed, 22 Jan 2020 08:19:24 -0500 Received: from gate.crashing.org (localhost.localdomain [127.0.0.1]) by gate.crashing.org (8.14.1/8.14.1) with ESMTP id 00MDIsXk010897; Wed, 22 Jan 2020 07:18:54 -0600 Received: (from segher@localhost) by gate.crashing.org (8.14.1/8.14.1/Submit) id 00MDIsPK010895; Wed, 22 Jan 2020 07:18:54 -0600 X-Authentication-Warning: gate.crashing.org: segher set sender to segher@kernel.crashing.org using -f Date: Wed, 22 Jan 2020 07:18:54 -0600 From: Segher Boessenkool To: Christophe Leroy Cc: Michael Ellerman , Benjamin Herrenschmidt , Paul Mackerras , ruscur@russell.cc, linux-kernel@vger.kernel.org, linuxppc-dev@lists.ozlabs.org Subject: Re: GCC bug ? Re: [PATCH v2 10/10] powerpc/32s: Implement Kernel Userspace Access Protection Message-ID: <20200122131854.GK3191@gate.crashing.org> References: <87ftqfu7j1.fsf@concordia.ellerman.id.au> <20200121195501.GJ3191@gate.crashing.org> <8501a33e-6c76-b6bd-9d8e-985313f94579@c-s.fr> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <8501a33e-6c76-b6bd-9d8e-985313f94579@c-s.fr> User-Agent: Mutt/1.4.2.3i Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi! On Wed, Jan 22, 2020 at 07:57:15AM +0100, Christophe Leroy wrote: > GCC doc also says: > > "if you use it in an inlined function and pass an argument of the > function as the argument to the built-in, GCC never returns 1 when you > call the inline function with a string constant" > > Does GCC considers (void*)0 as a string constant ? No, because it isn't (it's a pointer, not an array of characters). Segher