From: Arnd Bergmann <arnd@arndb.de>
To: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
Cc: linux-nvme@lists.infradead.org, Sean Young <sean@mess.org>,
linux-iio@vger.kernel.org, Daniel Vetter <daniel.vetter@ffwll.ch>,
linux-pci <linux-pci@vger.kernel.org>,
dri-devel <dri-devel@lists.freedesktop.org>,
Bjorn Andersson <bjorn.andersson@linaro.org>,
sparclinux <sparclinux@vger.kernel.org>,
driverdevel <devel@driverdev.osuosl.org>,
linux-scsi <linux-scsi@vger.kernel.org>,
linux-nvdimm@lists.01.org,
linux-rdma <linux-rdma@vger.kernel.org>,
qat-linux@intel.com, amd-gfx@lists.freedesktop.org,
Jason Gunthorpe <jgg@mellanox.com>,
"open list:HID CORE LAYER" <linux-input@vger.kernel.org>,
Darren Hart <dvhart@infradead.org>,
Linux Media Mailing List <linux-media@vger.kernel.org>,
linux-remoteproc@vger.kernel.org, linaro-mm-sig@lists.linaro.org,
Alexander Viro <viro@zeniv.linux.org.uk>,
Jonathan Cameron <Jonathan.Cameron@huawei.com>,
David Sterba <dsterba@suse.com>,
ceph
Subject: Re: [PATCH v3 12/26] compat_ioctl: move more drivers to compat_ptr_ioctl
Date: Thu, 25 Apr 2019 17:32:05 +0200 [thread overview]
Message-ID: <CAK8P3a1qCQJEkne3uAw-Ep-taNU9t5Y2ZmgoiCGmOz1BSwmzEw@mail.gmail.com> (raw)
In-Reply-To: <20190425122153.450fc094@coco.lan>
On Thu, Apr 25, 2019 at 5:22 PM Mauro Carvalho Chehab
<mchehab+samsung@kernel.org> wrote:
> Em Tue, 16 Apr 2019 22:25:33 +0200 Arnd Bergmann <arnd@arndb.de> 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
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next prev parent reply other threads:[~2019-04-25 15:32 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-04-16 20:19 [PATCH v3 00/26] compat_ioctl: cleanups Arnd Bergmann
2019-04-16 20:19 ` [PATCH v3 09/26] compat_ioctl: move drivers to compat_ptr_ioctl Arnd Bergmann
2019-04-16 20:31 ` Jiri Kosina
2019-04-18 11:10 ` Stefan Hajnoczi
2019-04-19 23:16 ` Michael S. Tsirkin
2019-04-20 8:03 ` Winkler, Tomas
[not found] ` <20190416202013.4034148-1-arnd-r2nGTMty4D4@public.gmane.org>
2019-04-16 20:25 ` [PATCH v3 12/26] compat_ioctl: move more " Arnd Bergmann
2019-04-25 15:21 ` Mauro Carvalho Chehab
2019-04-25 15:32 ` Arnd Bergmann [this message]
2019-04-25 15:35 ` Al Viro
2019-04-25 15:53 ` Mauro Carvalho Chehab
[not found] ` <20190425153534.GS2217-3bDd1+5oDREiFSDQTTA3OLVCufUGDwFn@public.gmane.org>
2019-04-25 15:55 ` Arnd Bergmann
2019-04-25 16:42 ` Al Viro
[not found] ` <CAK8P3a2HmiYQJ2FV2FgLiFsD8M9UKteC9Jetx7ja06PQVZWYfA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2019-04-25 21:25 ` Johannes Berg
[not found] ` <5511420228cb38d08a67c0f6a614b7671d7d23d4.camel-cdvu00un1VgdHxzADdlk8Q@public.gmane.org>
2019-04-26 7:46 ` Arnd Bergmann
2019-04-16 22:33 ` [PATCH v3 00/26] compat_ioctl: cleanups Douglas Gilbert
2019-04-17 9:26 ` Arnd Bergmann
2019-05-06 9:03 ` Andy Shevchenko
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