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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS autolearn=ham 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 51141C43219 for ; Thu, 25 Apr 2019 15:32:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 886762088F for ; Thu, 25 Apr 2019 15:32:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729661AbfDYPc3 (ORCPT ); Thu, 25 Apr 2019 11:32:29 -0400 Received: from mail-qt1-f196.google.com ([209.85.160.196]:44074 "EHLO mail-qt1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387593AbfDYPcZ (ORCPT ); Thu, 25 Apr 2019 11:32:25 -0400 Received: by mail-qt1-f196.google.com with SMTP id s10so504701qtc.11; Thu, 25 Apr 2019 08:32:23 -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=vnOK55Hhpegmo/fnJEz+TCVV+Rtg/rYKGc4878e+cQM=; b=UKuOoUy+U/DhO1lrIpJzV4Ph/CephrAcf/jKCSeUIeDvoHjzvpEnXC65Ukf9h1Ml3O /s3B+ucBFA/SCZiwvcG8m44SU5vaLq+cSoUpr+v97MybACPI8xSw+tBqbMtGey3O/dwh 7k6dvRZqNSLErq6sAvUOfdrbS3QsRH/LAtzQL7ZCp3VEV4Xa+tJDCKHFqhG4eUmFBOoA TdH5uTW+6TRa6B8E0jLoEj97uvssKvZFAGT30Y1GHSjPupev46xs0A2EzYdpKp1K0Cnc ECJ5zIKvJo3lKjWIAoD4lKDuRognkIEVFH3Eb+w7nBaxIUaAv8axd6sFg84VH9IhHe+7 WZ5Q== X-Gm-Message-State: APjAAAWLh3mra7FsjsrItm2wXSJLHGYq1pNo9wSfDkOc4Mfvr6JR7F6K S2gD/7PIlEI9SIS02upAVCHeANw0CRkAyRlXWeA= X-Google-Smtp-Source: APXvYqwxk/2uu8237YdCHmRUJfKvMCqEAFuyKk69MJnoHNCwVO4ijAI41YQVvxcBEABnP8bt18E+q4gxBK6hSfckd+U= X-Received: by 2002:ac8:2924:: with SMTP id y33mr30625898qty.212.1556206343098; Thu, 25 Apr 2019 08:32:23 -0700 (PDT) MIME-Version: 1.0 References: <20190416202013.4034148-1-arnd@arndb.de> <20190416202701.127745-1-arnd@arndb.de> <20190425122153.450fc094@coco.lan> In-Reply-To: <20190425122153.450fc094@coco.lan> From: Arnd Bergmann Date: Thu, 25 Apr 2019 17:32:05 +0200 Message-ID: Subject: Re: [PATCH v3 12/26] compat_ioctl: move more drivers to compat_ptr_ioctl To: Mauro Carvalho Chehab Cc: Alexander Viro , Linux FS-devel Mailing List , y2038 Mailman List , Linux Kernel Mailing List , Jason Gunthorpe , Daniel Vetter , Greg Kroah-Hartman , David Sterba , Darren Hart , Jonathan Cameron , Bjorn Andersson , driverdevel , qat-linux@intel.com, "open list:HARDWARE RANDOM NUMBER GENERATOR CORE" , Linux Media Mailing List , dri-devel , linaro-mm-sig@lists.linaro.org, amd-gfx@lists.freedesktop.org, "open list:HID CORE LAYER" , linux-iio@vger.kernel.org, linux-rdma , linux-nvdimm@lists.01.org, linux-nvme@lists.infradead.org, linux-pci , Platform Driver , linux-remoteproc@vger.kernel.org, sparclinux , linux-scsi , USB list , linux-btrfs , ceph-devel , linux-wireless , Networking , Sean Young Content-Type: text/plain; charset="UTF-8" Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Apr 25, 2019 at 5:22 PM Mauro Carvalho Chehab wrote: > Em Tue, 16 Apr 2019 22:25:33 +0200 Arnd Bergmann escreveu: > > If I understand your patch description well, using compat_ptr_ioctl > only works if the driver is not for s390, right? No, the purpose of compat_ptr_ioctl() is to make sure it works everywhere including s390. Even on s390 it tends to work most of the time, but for correctness the upper bit of a 32-bit pointer needs to be cleared, as compat_ptr_ioctl does, in case some application passes a pointer with that bit set. [IIRC, in the instruction pointer, the high bit is set, in data references it is ignored but usually cleared, but it may be left on for IP-relative address generation] Arnd