From mboxrd@z Thu Jan 1 00:00:00 1970 From: Al Viro Subject: Re: [PATCH v3 12/26] compat_ioctl: move more drivers to compat_ptr_ioctl Date: Thu, 25 Apr 2019 16:35:34 +0100 Message-ID: <20190425153534.GS2217@ZenIV.linux.org.uk> References: <20190416202013.4034148-1-arnd@arndb.de> <20190416202701.127745-1-arnd@arndb.de> <20190425122153.450fc094@coco.lan> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20190425122153.450fc094@coco.lan> Sender: linux-kernel-owner@vger.kernel.org To: Mauro Carvalho Chehab Cc: Arnd Bergmann , linux-fsdevel@vger.kernel.org, y2038@lists.linaro.org, linux-kernel@vger.kernel.org, Jason Gunthorpe , Daniel Vetter , Greg Kroah-Hartman , David Sterba , Darren Hart , Jonathan Cameron , Bjorn Andersson , devel@driverdev.osuosl.org, qat-linux@intel.com, linux-crypto@vger.kernel.org, linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, amd-gfx@lists.freedesktop.org, linux-input@vger.kernel.org, linux-iio@vger.kernel.org, linux-rdma@vger.kernel.org, linux-nvdimm@lists.01.org, linux-nvme@lists.infradead.org, linux-pci@vger.kernel.org List-Id: amd-gfx.lists.freedesktop.org On Thu, Apr 25, 2019 at 12:21:53PM -0300, Mauro Carvalho Chehab wrote: > If I understand your patch description well, using compat_ptr_ioctl > only works if the driver is not for s390, right? No; s390 is where "oh, just set ->compat_ioctl same as ->unlocked_ioctl and be done with that; compat_ptr() is a no-op anyway" breaks. IOW, s390 is the reason for having compat_ptr_ioctl() in the first place; that thing works on all biarch architectures, as long as all stuff handled by ->ioctl() takes pointer to arch-independent object as argument. IOW, argument ignored => OK any arithmetical type => no go, compat_ptr() would bugger it pointer to int => OK pointer to string => OK pointer to u64 => OK pointer to struct {u64 addr; char s[11];} => OK pointer to long => needs explicit handler pointer to struct {void *addr; char s[11];} => needs explicit handler pointer to struct {int x; u64 y;} => needs explicit handler on amd64 For "just use ->unlocked_ioctl for ->ioctl" we have argument ignored => OK any arithmetical type => OK any pointer => instant breakage on s390, in addtion to cases that break with compat_ptr_ioctl(). Probably some form of that ought to go into commit message for compat_ptr_ioctl() introduction... 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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 9BE85C43219 for ; Thu, 25 Apr 2019 15:36:07 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D48472081C for ; Thu, 25 Apr 2019 15:36:07 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727342AbfDYPfs (ORCPT ); Thu, 25 Apr 2019 11:35:48 -0400 Received: from zeniv.linux.org.uk ([195.92.253.2]:47236 "EHLO ZenIV.linux.org.uk" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726229AbfDYPfr (ORCPT ); Thu, 25 Apr 2019 11:35:47 -0400 Received: from viro by ZenIV.linux.org.uk with local (Exim 4.92 #3 (Red Hat Linux)) id 1hJgPO-0002EI-Tp; Thu, 25 Apr 2019 15:35:35 +0000 Date: Thu, 25 Apr 2019 16:35:34 +0100 From: Al Viro To: Mauro Carvalho Chehab Cc: Arnd Bergmann , linux-fsdevel@vger.kernel.org, y2038@lists.linaro.org, linux-kernel@vger.kernel.org, Jason Gunthorpe , Daniel Vetter , Greg Kroah-Hartman , David Sterba , Darren Hart , Jonathan Cameron , Bjorn Andersson , devel@driverdev.osuosl.org, qat-linux@intel.com, linux-crypto@vger.kernel.org, linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, amd-gfx@lists.freedesktop.org, linux-input@vger.kernel.org, linux-iio@vger.kernel.org, linux-rdma@vger.kernel.org, linux-nvdimm@lists.01.org, linux-nvme@lists.infradead.org, linux-pci@vger.kernel.org, platform-driver-x86@vger.kernel.org, linux-remoteproc@vger.kernel.org, sparclinux@vger.kernel.org, linux-scsi@vger.kernel.org, linux-usb@vger.kernel.org, linux-btrfs@vger.kernel.org, ceph-devel@vger.kernel.org, linux-wireless@vger.kernel.org, netdev@vger.kernel.org, Sean Young Subject: Re: [PATCH v3 12/26] compat_ioctl: move more drivers to compat_ptr_ioctl Message-ID: <20190425153534.GS2217@ZenIV.linux.org.uk> References: <20190416202013.4034148-1-arnd@arndb.de> <20190416202701.127745-1-arnd@arndb.de> <20190425122153.450fc094@coco.lan> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20190425122153.450fc094@coco.lan> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org On Thu, Apr 25, 2019 at 12:21:53PM -0300, Mauro Carvalho Chehab wrote: > If I understand your patch description well, using compat_ptr_ioctl > only works if the driver is not for s390, right? No; s390 is where "oh, just set ->compat_ioctl same as ->unlocked_ioctl and be done with that; compat_ptr() is a no-op anyway" breaks. IOW, s390 is the reason for having compat_ptr_ioctl() in the first place; that thing works on all biarch architectures, as long as all stuff handled by ->ioctl() takes pointer to arch-independent object as argument. IOW, argument ignored => OK any arithmetical type => no go, compat_ptr() would bugger it pointer to int => OK pointer to string => OK pointer to u64 => OK pointer to struct {u64 addr; char s[11];} => OK pointer to long => needs explicit handler pointer to struct {void *addr; char s[11];} => needs explicit handler pointer to struct {int x; u64 y;} => needs explicit handler on amd64 For "just use ->unlocked_ioctl for ->ioctl" we have argument ignored => OK any arithmetical type => OK any pointer => instant breakage on s390, in addtion to cases that break with compat_ptr_ioctl(). Probably some form of that ought to go into commit message for compat_ptr_ioctl() introduction... From mboxrd@z Thu Jan 1 00:00:00 1970 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: base64 Subject: [v3,12/26] compat_ioctl: move more drivers to compat_ptr_ioctl From: Al Viro Message-Id: <20190425153534.GS2217@ZenIV.linux.org.uk> Date: Thu, 25 Apr 2019 16:35:34 +0100 To: Mauro Carvalho Chehab Cc: Arnd Bergmann , linux-fsdevel@vger.kernel.org, y2038@lists.linaro.org, linux-kernel@vger.kernel.org, Jason Gunthorpe , Daniel Vetter , Greg Kroah-Hartman , David Sterba , Darren Hart , Jonathan Cameron , Bjorn Andersson , devel@driverdev.osuosl.org, qat-linux@intel.com, linux-crypto@vger.kernel.org, linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, amd-gfx@lists.freedesktop.org, linux-input@vger.kernel.org, linux-iio@vger.kernel.org, linux-rdma@vger.kernel.org, linux-nvdimm@lists.01.org, linux-nvme@lists.infradead.org, linux-pci@vger.kernel.org, platform-driver-x86@vger.kernel.org, linux-remoteproc@vger.kernel.org, sparclinux@vger.kernel.org, linux-scsi@vger.kernel.org, linux-usb@vger.kernel.org, linux-btrfs@vger.kernel.org, ceph-devel@vger.kernel.org, linux-wireless@vger.kernel.org, netdev@vger.kernel.org, Sean Young List-ID: T24gVGh1LCBBcHIgMjUsIDIwMTkgYXQgMTI6MjE6NTNQTSAtMDMwMCwgTWF1cm8gQ2FydmFsaG8g Q2hlaGFiIHdyb3RlOgoKPiBJZiBJIHVuZGVyc3RhbmQgeW91ciBwYXRjaCBkZXNjcmlwdGlvbiB3 ZWxsLCB1c2luZyBjb21wYXRfcHRyX2lvY3RsCj4gb25seSB3b3JrcyBpZiB0aGUgZHJpdmVyIGlz IG5vdCBmb3IgczM5MCwgcmlnaHQ/CgpObzsgczM5MCBpcyB3aGVyZSAib2gsIGp1c3Qgc2V0IC0+ Y29tcGF0X2lvY3RsIHNhbWUgYXMgLT51bmxvY2tlZF9pb2N0bAphbmQgYmUgZG9uZSB3aXRoIHRo YXQ7IGNvbXBhdF9wdHIoKSBpcyBhIG5vLW9wIGFueXdheSIgYnJlYWtzLiAgSU9XLApzMzkwIGlz IHRoZSByZWFzb24gZm9yIGhhdmluZyBjb21wYXRfcHRyX2lvY3RsKCkgaW4gdGhlIGZpcnN0IHBs YWNlOwp0aGF0IHRoaW5nIHdvcmtzIG9uIGFsbCBiaWFyY2ggYXJjaGl0ZWN0dXJlcywgYXMgbG9u ZyBhcyBhbGwgc3R1ZmYKaGFuZGxlZCBieSAtPmlvY3RsKCkgdGFrZXMgcG9pbnRlciB0byBhcmNo LWluZGVwZW5kZW50IG9iamVjdCBhcwphcmd1bWVudC4gIElPVywKCWFyZ3VtZW50IGlnbm9yZWQg PT4gT0sKCWFueSBhcml0aG1ldGljYWwgdHlwZSA9PiBubyBnbywgY29tcGF0X3B0cigpIHdvdWxk IGJ1Z2dlciBpdAoJcG9pbnRlciB0byBpbnQgPT4gT0sKCXBvaW50ZXIgdG8gc3RyaW5nID0+IE9L Cglwb2ludGVyIHRvIHU2NCA9PiBPSwoJcG9pbnRlciB0byBzdHJ1Y3Qge3U2NCBhZGRyOyBjaGFy IHNbMTFdO30gPT4gT0sKCXBvaW50ZXIgdG8gbG9uZyA9PiBuZWVkcyBleHBsaWNpdCBoYW5kbGVy Cglwb2ludGVyIHRvIHN0cnVjdCB7dm9pZCAqYWRkcjsgY2hhciBzWzExXTt9ID0+IG5lZWRzIGV4 cGxpY2l0IGhhbmRsZXIKCXBvaW50ZXIgdG8gc3RydWN0IHtpbnQgeDsgdTY0IHk7fSA9PiBuZWVk cyBleHBsaWNpdCBoYW5kbGVyIG9uIGFtZDY0CkZvciAianVzdCB1c2UgLT51bmxvY2tlZF9pb2N0 bCBmb3IgLT5pb2N0bCIgd2UgaGF2ZQoJYXJndW1lbnQgaWdub3JlZCA9PiBPSwoJYW55IGFyaXRo bWV0aWNhbCB0eXBlID0+IE9LCglhbnkgcG9pbnRlciA9PiBpbnN0YW50IGJyZWFrYWdlIG9uIHMz OTAsIGluIGFkZHRpb24gdG8gY2FzZXMgdGhhdCBicmVhawp3aXRoIGNvbXBhdF9wdHJfaW9jdGwo KS4KClByb2JhYmx5IHNvbWUgZm9ybSBvZiB0aGF0IG91Z2h0IHRvIGdvIGludG8gY29tbWl0IG1l c3NhZ2UgZm9yIGNvbXBhdF9wdHJfaW9jdGwoKQppbnRyb2R1Y3Rpb24uLi4K From mboxrd@z Thu Jan 1 00:00:00 1970 From: Al Viro Date: Thu, 25 Apr 2019 15:35:34 +0000 Subject: Re: [PATCH v3 12/26] compat_ioctl: move more drivers to compat_ptr_ioctl Message-Id: <20190425153534.GS2217@ZenIV.linux.org.uk> List-Id: References: <20190416202013.4034148-1-arnd@arndb.de> <20190416202701.127745-1-arnd@arndb.de> <20190425122153.450fc094@coco.lan> In-Reply-To: <20190425122153.450fc094@coco.lan> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Mauro Carvalho Chehab Cc: Arnd Bergmann , linux-fsdevel@vger.kernel.org, y2038@lists.linaro.org, linux-kernel@vger.kernel.org, Jason Gunthorpe , Daniel Vetter , Greg Kroah-Hartman , David Sterba , Darren Hart , Jonathan Cameron , Bjorn Andersson , devel@driverdev.osuosl.org, qat-linux@intel.com, linux-crypto@vger.kernel.org, linux-media@vger.kernel.org, dri-devel@lists.freedesktop.org, linaro-mm-sig@lists.linaro.org, amd-gfx@lists.freedesktop.org, linux-input@vger.kernel.org, linux-iio@vger.kernel.org, linux-rdma@vger.kernel.org, linux-nvdimm@lists.01.org, linux-nvme@lists.infradead.org, linux-pci@vger.kernel.org On Thu, Apr 25, 2019 at 12:21:53PM -0300, Mauro Carvalho Chehab wrote: > If I understand your patch description well, using compat_ptr_ioctl > only works if the driver is not for s390, right? No; s390 is where "oh, just set ->compat_ioctl same as ->unlocked_ioctl and be done with that; compat_ptr() is a no-op anyway" breaks. IOW, s390 is the reason for having compat_ptr_ioctl() in the first place; that thing works on all biarch architectures, as long as all stuff handled by ->ioctl() takes pointer to arch-independent object as argument. IOW, argument ignored => OK any arithmetical type => no go, compat_ptr() would bugger it pointer to int => OK pointer to string => OK pointer to u64 => OK pointer to struct {u64 addr; char s[11];} => OK pointer to long => needs explicit handler pointer to struct {void *addr; char s[11];} => needs explicit handler pointer to struct {int x; u64 y;} => needs explicit handler on amd64 For "just use ->unlocked_ioctl for ->ioctl" we have argument ignored => OK any arithmetical type => OK any pointer => instant breakage on s390, in addtion to cases that break with compat_ptr_ioctl(). Probably some form of that ought to go into commit message for compat_ptr_ioctl() introduction...