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=-8.5 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE, SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 D5D50C43461 for ; Thu, 3 Sep 2020 16:33:49 +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 940B920578 for ; Thu, 3 Sep 2020 16:33:49 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 940B920578 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=lst.de Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Received: from bilbo.ozlabs.org (lists.ozlabs.org [IPv6:2401:3900:2:1::3]) by lists.ozlabs.org (Postfix) with ESMTP id 4Bj5wT6ysfzDqxQ for ; Fri, 4 Sep 2020 02:33:45 +1000 (AEST) Authentication-Results: lists.ozlabs.org; spf=none (no SPF record) smtp.mailfrom=lst.de (client-ip=213.95.11.211; helo=verein.lst.de; envelope-from=hch@lst.de; receiver=) Authentication-Results: lists.ozlabs.org; dmarc=none (p=none dis=none) header.from=lst.de Received: from verein.lst.de (verein.lst.de [213.95.11.211]) (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 4Bj4x572zKzDrBH for ; Fri, 4 Sep 2020 01:49:13 +1000 (AEST) Received: by verein.lst.de (Postfix, from userid 2407) id 5E5A767357; Thu, 3 Sep 2020 17:49:09 +0200 (CEST) Date: Thu, 3 Sep 2020 17:49:09 +0200 From: Christoph Hellwig To: Christophe Leroy Subject: Re: [PATCH 14/14] powerpc: remove address space overrides using set_fs() Message-ID: <20200903154909.GA23023@lst.de> References: <20200903142242.925828-1-hch@lst.de> <20200903142242.925828-15-hch@lst.de> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.5.17 (2007-11-01) 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-arch@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, Kees Cook , x86@kernel.org, linux-kernel@vger.kernel.org, Alexey Dobriyan , Luis Chamberlain , Al Viro , linux-fsdevel@vger.kernel.org, Linus Torvalds , Christoph Hellwig Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Thu, Sep 03, 2020 at 05:43:25PM +0200, Christophe Leroy wrote: > > > Le 03/09/2020 à 16:22, Christoph Hellwig a écrit : >> Stop providing the possibility to override the address space using >> set_fs() now that there is no need for that any more. >> >> Signed-off-by: Christoph Hellwig >> --- > > >> -static inline int __access_ok(unsigned long addr, unsigned long size, >> - mm_segment_t seg) >> +static inline bool __access_ok(unsigned long addr, unsigned long size) >> { >> - if (addr > seg.seg) >> - return 0; >> - return (size == 0 || size - 1 <= seg.seg - addr); >> + if (addr >= TASK_SIZE_MAX) >> + return false; >> + return size == 0 || size <= TASK_SIZE_MAX - addr; >> } > > You don't need to test size == 0 anymore. It used to be necessary because > of the 'size - 1', as size is unsigned. > > Now you can directly do > > return size <= TASK_SIZE_MAX - addr; > > If size is 0, this will always be true (because you already know that addr > is not >= TASK_SIZE_MAX True. What do you think of Linus' comment about always using the ppc32 version on ppc64 as well with this?