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=-3.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 7A287C432BE for ; Mon, 23 Aug 2021 21:58:05 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5A56361374 for ; Mon, 23 Aug 2021 21:58:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233003AbhHWV6r convert rfc822-to-8bit (ORCPT ); Mon, 23 Aug 2021 17:58:47 -0400 Received: from foss.arm.com ([217.140.110.172]:57436 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232898AbhHWV6o (ORCPT ); Mon, 23 Aug 2021 17:58:44 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id E99BD1042; Mon, 23 Aug 2021 14:58:00 -0700 (PDT) Received: from [127.0.0.1] (unknown [172.31.20.19]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 7ABFA3F766; Mon, 23 Aug 2021 14:58:00 -0700 (PDT) Date: Mon, 23 Aug 2021 22:57:56 +0100 From: Steven Price To: dri-devel@lists.freedesktop.org, Alyssa Rosenzweig CC: Alyssa Rosenzweig , Rob Herring , Tomeu Vizoso , David Airlie , Daniel Vetter , linux-kernel@vger.kernel.org, Chris Morgan Subject: Re: [PATCH 2/3] drm/panfrost: Use u64 for size in lock_region User-Agent: K-9 Mail for Android In-Reply-To: References: <20210820213117.13050-1-alyssa.rosenzweig@collabora.com> <20210820213117.13050-3-alyssa.rosenzweig@collabora.com> <71392001-a5a9-fee2-79a5-91df55ba3081@arm.com> Message-ID: <77CFD756-7F02-4CBA-9E58-3EDA2167620E@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 23 August 2021 22:11:09 BST, Alyssa Rosenzweig wrote: >> > Mali virtual addresses are 48-bit. Use a u64 instead of size_t to ensure >> > we can express the "lock everything" condition as ~0ULL without relying >> > on platform-specific behaviour. >> >> 'platform-specific behaviour' makes it sound like this is something to >> do with a particular board. This is 32bit/64bit - it's going to be >> broken on 32bit: large lock regions are not going to work. > >Oh, my. I used the term as a weasel word since the spec is loose on how >big a size_t actually is. But if this is causing actual breakage on >armv7 we're in trouble. I'll add a Cc stable tag on v2, unless the Fixes >implies that? The usual practice is to put CC: stable in the commit message or the fixes tag (no need to actually CC the stable email address). So just Fixes: should work >Thanks for pointing this out. It's not actually quite so bad as it could be as >4GB regions are unlikely (especially on 32bit), but the GPU does of course support such a thing. Thanks, Steve