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 638C7C4320A for ; Tue, 31 Aug 2021 17:19:43 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A6831611C6 for ; Tue, 31 Aug 2021 17:19:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240290AbhHaRUf (ORCPT ); Tue, 31 Aug 2021 13:20:35 -0400 Received: from mail-vs1-f46.google.com ([209.85.217.46]:36767 "EHLO mail-vs1-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S240116AbhHaRUf (ORCPT ); Tue, 31 Aug 2021 13:20:35 -0400 Received: by mail-vs1-f46.google.com with SMTP id f6so144423vsr.3; Tue, 31 Aug 2021 10:19:39 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=UMOX2To1IEOY2ZnzUeCxb0+BBk/jcmCPbhrdDzxJbcg=; b=sZ7uWxlzeUzmgbLH688QWiQjFRdZTH/FLRn9HPOMIFACKocPntakFs5ZRfmkQDek1q Gg1Aeenc897704wRSaSdZZAAeElRFdXeqrEa9GaSS1CvFovF+Sd/YKEAga1Pa0g/dfXS jzHb4CGyylMPfSjujzt6La0Ga5tgna8EIuhH/5Eev76u5ytQd5hZ+ZN/HOSvL50aa+18 02EmNsBX6OKEiRXNAEnwqCZckoGS+Goo9RLwuiU8N787HViLjDiF0D6Dz6JBwej9s9to V2NIel8Byqug/Rn0btbdv2p6FlITC9EYxcyu0ZF+rZQpmb/HOMoT5D1qQ0gJZ5kesQfb ETnw== X-Gm-Message-State: AOAM532aSr3K4iyzRS6qLxw3hR84jGWvQjEFIz+2LrPhu8ZIhfXhaQLj HeQkeF69fHGL5KQDNuVEOY4PrW3eZEmQ2as3Wuc= X-Google-Smtp-Source: ABdhPJzwIcYtEYXT+4ELrSXZhc7SGBnDBykZ6QWPifjhJFCJ02Jh+wK9QnEW6KWY0HcJvsALfiP7/h+mMWcZEJ7eWpI= X-Received: by 2002:a67:c789:: with SMTP id t9mr20435604vsk.60.1630430379297; Tue, 31 Aug 2021 10:19:39 -0700 (PDT) MIME-Version: 1.0 References: <000000000000815b9605c70e74f8@google.com> <131b24e5-ee31-6f7b-42b4-c34583711913@infradead.org> <2fccb5d3-191c-924e-159f-1c9d423e282f@i-love.sakura.ne.jp> <339bfb21-8e80-c7d9-46dd-c416f87c50c0@infradead.org> <535e404d-03bf-8e7a-b296-132a2a98c599@i-love.sakura.ne.jp> <5c6d2b95-31d7-0d59-5e62-2593d9a0e1fe@i-love.sakura.ne.jp> In-Reply-To: <5c6d2b95-31d7-0d59-5e62-2593d9a0e1fe@i-love.sakura.ne.jp> From: Geert Uytterhoeven Date: Tue, 31 Aug 2021 19:19:27 +0200 Message-ID: Subject: Re: [PATCH] fbmem: don't allow too huge resolutions To: Tetsuo Handa Cc: Daniel Vetter , syzbot , Andrew Morton , Bartlomiej Zolnierkiewicz , Colin King , DRI Development , Linux Fbdev development list , Linux Kernel Mailing List , Masahiro Yamada , syzkaller-bugs@googlegroups.com, Randy Dunlap Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-fbdev@vger.kernel.org Hi Handa-san, On Tue, Aug 31, 2021 at 5:24 PM Tetsuo Handa wrote: > On 2021/08/31 15:48, Geert Uytterhoeven wrote: > > Furthermore, this restricts the virtual frame buffer size on 64-bit, > > too, while graphics cards can have much more than 4 GiB of RAM. > > Excuse me, but do you mean that some hardware allows allocating more than > UINT_MAX bytes of memory for kernel frame buffer drivers? While smem_len is u32 (there have been complaints about such limitations on 64-bit platforms as far as 10 years ago), I see no reason why a graphics card with more than 4 GiB of RAM would not be able to provide a very large virtual screen. Of course e.g. vga16fb cannot, as it is limited to 64 KiB. Gr{oetje,eeting}s, Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that. -- Linus Torvalds